Agenda packet — Aliso Viejo City Council, October 21, 2026 (part 6 of 8)

TIME OF CONCENTRATION(MIN.) = 9.34
RAINFALL INTENSITY(INCH/HR) = 3.39
AREA-AVERAGED Fm(INCH/HR) = 0.04 AREA-AVERAGED Fp(INCH/HR) = 0.20 AREA-AVERAGED Ap = 0.20
EFFECTIVE STREAM AREA(ACRES) = 0.40
TOTAL STREAM AREA(ACRES) = 0.40
PEAK FLOW RATE(CFS) AT CONFLUENCE = 1.24
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 1.46 11.18 3.060 0.20( 0.20) 1.00 0.6 300.00 2 1.24 9.34 3.387 0.20( 0.04) 0.20 0.4 400.00

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
1177
11 NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE 1 2.59 9.34 3.387 0.20( 0.13) 0.63 0.9 400.00 2 2.57 11.18 3.060 0.20( 0.13) 0.67 1.0 300.00 COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 2.59 Tc(MIN.) = 9.34
EFFECTIVE AREA(ACRES) = 0.87 AREA-AVERAGED Fm(INCH/HR) = 0.13 AREA-AVERAGED Fp(INCH/HR) = 0.20 AREA-AVERAGED Ap = 0.63 TOTAL AREA(ACRES) = 1.0
LONGEST FLOWPATH FROM NODE 300.00 TO NODE 305.00 = 383.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 305.00 TO NODE 310.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 349.30 DOWNSTREAM(FEET) = 345.00 FLOW LENGTH(FEET) = 144.00 MANNING'S N = 0.012
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 4.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 7.56
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 2.59
PIPE TRAVEL TIME(MIN.) = 0.32 Tc(MIN.) = 9.65
LONGEST FLOWPATH FROM NODE 300.00 TO NODE 310.00 = 527.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 310.00 TO NODE 310.00 IS CODE = 10 ---------------------------------------------------------------------------- >>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 2 <<<<< ============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 500.00 TO NODE 501.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 144.00
ELEVATION DATA: UPSTREAM(FEET) = 370.00 DOWNSTREAM(FEET) = 361.00 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 8.974
* 25 YEAR RAINFALL INTENSITY(INCH/HR) = 3.464
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)

NATURAL FAIR COVER
"OPEN BRUSH" D 0.16 0.20 1.000 83 8.97
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.20
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 1.000
SUBAREA RUNOFF(CFS) = 0.47
TOTAL AREA(ACRES) = 0.16 PEAK FLOW RATE(CFS) = 0.47
12 **************************************************************************** FLOW PROCESS FROM NODE 501.00 TO NODE 505.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 349.00 DOWNSTREAM(FEET) = 347.00 FLOW LENGTH(FEET) = 175.00 MANNING'S N = 0.012
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 2.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 3.25
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 0.47
PIPE TRAVEL TIME(MIN.) = 0.90 Tc(MIN.) = 9.87
LONGEST FLOWPATH FROM NODE 500.00 TO NODE 505.00 = 319.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 505.00 TO NODE 505.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 9.87
RAINFALL INTENSITY(INCH/HR) = 3.28
AREA-AVERAGED Fm(INCH/HR) = 0.20 AREA-AVERAGED Fp(INCH/HR) = 0.20 AREA-AVERAGED Ap = 1.00
EFFECTIVE STREAM AREA(ACRES) = 0.16
TOTAL STREAM AREA(ACRES) = 0.16
PEAK FLOW RATE(CFS) AT CONFLUENCE = 0.47
**************************************************************************** FLOW PROCESS FROM NODE 502.00 TO NODE 503.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 263.00
ELEVATION DATA: UPSTREAM(FEET) = 356.50 DOWNSTREAM(FEET) = 352.70 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 7.024
* 25 YEAR RAINFALL INTENSITY(INCH/HR) = 3.980
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.) APARTMENTS D 0.50 0.20 0.200 75 7.02 SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.20
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.200
SUBAREA RUNOFF(CFS) = 1.77
TOTAL AREA(ACRES) = 0.50 PEAK FLOW RATE(CFS) = 1.77
**************************************************************************** FLOW PROCESS FROM NODE 503.00 TO NODE 504.00 IS CODE = 31 1178
13 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 347.50 DOWNSTREAM(FEET) = 347.40 FLOW LENGTH(FEET) = 23.00 MANNING'S N = 0.012
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 6.0 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 3.42
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 1.77
PIPE TRAVEL TIME(MIN.) = 0.11 Tc(MIN.) = 7.14
LONGEST FLOWPATH FROM NODE 502.00 TO NODE 504.00 = 286.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 504.00 TO NODE 504.00 IS CODE = 81 ---------------------------------------------------------------------------- >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================ MAINLINE Tc(MIN.) = 7.14
* 25 YEAR RAINFALL INTENSITY(INCH/HR) = 3.944
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN APARTMENTS D 0.25 0.20 0.200 75 SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.20
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.200
SUBAREA AREA(ACRES) = 0.25 SUBAREA RUNOFF(CFS) = 0.88
EFFECTIVE AREA(ACRES) = 0.75 AREA-AVERAGED Fm(INCH/HR) = 0.04 AREA-AVERAGED Fp(INCH/HR) = 0.20 AREA-AVERAGED Ap = 0.20 TOTAL AREA(ACRES) = 0.8 PEAK FLOW RATE(CFS) = 2.64
**************************************************************************** FLOW PROCESS FROM NODE 504.00 TO NODE 505.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 347.40 DOWNSTREAM(FEET) = 347.00 FLOW LENGTH(FEET) = 45.00 MANNING'S N = 0.012
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 6.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.93
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 2.64
PIPE TRAVEL TIME(MIN.) = 0.15 Tc(MIN.) = 7.29
LONGEST FLOWPATH FROM NODE 502.00 TO NODE 505.00 = 331.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 505.00 TO NODE 505.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
14 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 7.29
RAINFALL INTENSITY(INCH/HR) = 3.90
AREA-AVERAGED Fm(INCH/HR) = 0.04 AREA-AVERAGED Fp(INCH/HR) = 0.20 AREA-AVERAGED Ap = 0.20
EFFECTIVE STREAM AREA(ACRES) = 0.75
TOTAL STREAM AREA(ACRES) = 0.75
PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.64
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 0.47 9.87 3.282 0.20( 0.20) 1.00 0.2 500.00 2 2.64 7.29 3.897 0.20( 0.04) 0.20 0.8 502.00

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 3.05 7.29 3.897 0.20( 0.06) 0.31 0.9 502.00 2 2.69 9.87 3.282 0.20( 0.07) 0.34 0.9 500.00 COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 3.05 Tc(MIN.) = 7.29
EFFECTIVE AREA(ACRES) = 0.87 AREA-AVERAGED Fm(INCH/HR) = 0.06 AREA-AVERAGED Fp(INCH/HR) = 0.20 AREA-AVERAGED Ap = 0.31 TOTAL AREA(ACRES) = 0.9
LONGEST FLOWPATH FROM NODE 502.00 TO NODE 505.00 = 331.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 505.00 TO NODE 506.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 347.00 DOWNSTREAM(FEET) = 346.80 FLOW LENGTH(FEET) = 25.00 MANNING'S N = 0.012
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 6.9 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.94
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 3.05
PIPE TRAVEL TIME(MIN.) = 0.08 Tc(MIN.) = 7.37
LONGEST FLOWPATH FROM NODE 502.00 TO NODE 506.00 = 356.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 506.00 TO NODE 506.00 IS CODE = 81 ---------------------------------------------------------------------------- >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================ MAINLINE Tc(MIN.) = 7.37
* 25 YEAR RAINFALL INTENSITY(INCH/HR) = 3.872
1179
15 SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN APARTMENTS D 0.81 0.20 0.200 75 SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.20
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.200
SUBAREA AREA(ACRES) = 0.81 SUBAREA RUNOFF(CFS) = 2.79
EFFECTIVE AREA(ACRES) = 1.68 AREA-AVERAGED Fm(INCH/HR) = 0.05 AREA-AVERAGED Fp(INCH/HR) = 0.20 AREA-AVERAGED Ap = 0.26 TOTAL AREA(ACRES) = 1.7 PEAK FLOW RATE(CFS) = 5.77
**************************************************************************** FLOW PROCESS FROM NODE 506.00 TO NODE 507.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 346.80 DOWNSTREAM(FEET) = 345.70 FLOW LENGTH(FEET) = 139.00 MANNING'S N = 0.012
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 9.9 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 5.80
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 5.77
PIPE TRAVEL TIME(MIN.) = 0.40 Tc(MIN.) = 7.77
LONGEST FLOWPATH FROM NODE 502.00 TO NODE 507.00 = 495.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 507.00 TO NODE 507.00 IS CODE = 81 ---------------------------------------------------------------------------- >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================ MAINLINE Tc(MIN.) = 7.77
* 25 YEAR RAINFALL INTENSITY(INCH/HR) = 3.758
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN APARTMENTS D 0.96 0.20 0.200 75 SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.20
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.200
SUBAREA AREA(ACRES) = 0.96 SUBAREA RUNOFF(CFS) = 3.21
EFFECTIVE AREA(ACRES) = 2.64 AREA-AVERAGED Fm(INCH/HR) = 0.05 AREA-AVERAGED Fp(INCH/HR) = 0.20 AREA-AVERAGED Ap = 0.24 TOTAL AREA(ACRES) = 2.7 PEAK FLOW RATE(CFS) = 8.81
**************************************************************************** FLOW PROCESS FROM NODE 507.00 TO NODE 310.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 345.70 DOWNSTREAM(FEET) = 345.00 FLOW LENGTH(FEET) = 87.00 MANNING'S N = 0.012
DEPTH OF FLOW IN 18.0 INCH PIPE IS 13.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.36
16 ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 8.81
PIPE TRAVEL TIME(MIN.) = 0.23 Tc(MIN.) = 8.00
LONGEST FLOWPATH FROM NODE 502.00 TO NODE 310.00 = 582.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 310.00 TO NODE 310.00 IS CODE = 11 ---------------------------------------------------------------------------- >>>>>CONFLUENCE MEMORY BANK # 2 WITH THE MAIN-STREAM MEMORY<<<<< ============================================================================ ** MAIN STREAM CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 8.81 8.00 3.697 0.20( 0.05) 0.24 2.6 502.00 2 7.58 10.61 3.152 0.20( 0.05) 0.25 2.7 500.00 LONGEST FLOWPATH FROM NODE 502.00 TO NODE 310.00 = 582.00 FEET. ** MEMORY BANK # 2 CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 2.59 9.65 3.324 0.20( 0.13) 0.63 0.9 400.00 2 2.57 11.49 3.011 0.20( 0.13) 0.67 1.0 300.00 LONGEST FLOWPATH FROM NODE 300.00 TO NODE 310.00 = 527.00 FEET. ** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 11.21 8.00 3.697 0.20( 0.06) 0.32 3.4 502.00 2 10.62 9.65 3.324 0.20( 0.07) 0.34 3.5 400.00 3 10.16 10.61 3.152 0.20( 0.07) 0.35 3.6 500.00 4 9.81 11.49 3.011 0.20( 0.07) 0.36 3.6 300.00 TOTAL AREA(ACRES) = 3.6
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 11.21 Tc(MIN.) = 7.999
EFFECTIVE AREA(ACRES) = 3.36 AREA-AVERAGED Fm(INCH/HR) = 0.06 AREA-AVERAGED Fp(INCH/HR) = 0.20 AREA-AVERAGED Ap = 0.32 TOTAL AREA(ACRES) = 3.6
LONGEST FLOWPATH FROM NODE 502.00 TO NODE 310.00 = 582.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 310.00 TO NODE 315.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 345.00 DOWNSTREAM(FEET) = 342.30 FLOW LENGTH(FEET) = 275.00 MANNING'S N = 0.012
DEPTH OF FLOW IN 21.0 INCH PIPE IS 12.7 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 7.40
ESTIMATED PIPE DIAMETER(INCH) = 21.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 11.21
PIPE TRAVEL TIME(MIN.) = 0.62 Tc(MIN.) = 8.62
LONGEST FLOWPATH FROM NODE 502.00 TO NODE 315.00 = 857.00 FEET. 1180
17 **************************************************************************** FLOW PROCESS FROM NODE 315.00 TO NODE 315.00 IS CODE = 81 ---------------------------------------------------------------------------- >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================ MAINLINE Tc(MIN.) = 8.62
* 25 YEAR RAINFALL INTENSITY(INCH/HR) = 3.544
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN APARTMENTS D 0.76 0.20 0.200 75 SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.20
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.200
SUBAREA AREA(ACRES) = 0.76 SUBAREA RUNOFF(CFS) = 2.40
EFFECTIVE AREA(ACRES) = 4.12 AREA-AVERAGED Fm(INCH/HR) = 0.06 AREA-AVERAGED Fp(INCH/HR) = 0.20 AREA-AVERAGED Ap = 0.30 TOTAL AREA(ACRES) = 4.4 PEAK FLOW RATE(CFS) = 12.91
**************************************************************************** FLOW PROCESS FROM NODE 315.00 TO NODE 110.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 342.30 DOWNSTREAM(FEET) = 342.00 FLOW LENGTH(FEET) = 24.00 MANNING'S N = 0.012
DEPTH OF FLOW IN 21.0 INCH PIPE IS 12.8 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.39
ESTIMATED PIPE DIAMETER(INCH) = 21.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 12.91
PIPE TRAVEL TIME(MIN.) = 0.05 Tc(MIN.) = 8.67
LONGEST FLOWPATH FROM NODE 502.00 TO NODE 110.00 = 881.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 110.00 TO NODE 110.00 IS CODE = 11 ---------------------------------------------------------------------------- >>>>>CONFLUENCE MEMORY BANK # 1 WITH THE MAIN-STREAM MEMORY<<<<< ============================================================================ ** MAIN STREAM CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 12.91 8.67 3.533 0.20( 0.06) 0.30 4.1 502.00 2 12.14 10.35 3.195 0.20( 0.06) 0.31 4.3 400.00 3 11.69 11.31 3.040 0.20( 0.06) 0.32 4.4 500.00 4 11.30 12.20 2.912 0.20( 0.07) 0.33 4.4 300.00 LONGEST FLOWPATH FROM NODE 502.00 TO NODE 110.00 = 881.00 FEET. ** MEMORY BANK # 1 CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 6.44 6.86 4.032 0.20( 0.06) 0.30 1.7 210.00 2 7.77 12.91 2.820 0.20( 0.06) 0.30 3.1 200.00 3 7.54 13.72 2.724 0.20( 0.06) 0.31 3.1 100.00 18 LONGEST FLOWPATH FROM NODE 100.00 TO NODE 110.00 = 1157.00 FEET. ** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 18.13 6.86 4.032 0.20( 0.06) 0.30 5.0 210.00 2 19.75 8.67 3.533 0.20( 0.06) 0.30 6.3 502.00 3 19.34 10.35 3.195 0.20( 0.06) 0.31 6.8 400.00 4 19.11 11.31 3.040 0.20( 0.06) 0.32 7.1 500.00 5 18.91 12.20 2.912 0.20( 0.06) 0.32 7.3 300.00 6 18.70 12.91 2.820 0.20( 0.06) 0.32 7.5 200.00 7 18.09 13.72 2.724 0.20( 0.06) 0.32 7.5 100.00 TOTAL AREA(ACRES) = 7.5
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 19.75 Tc(MIN.) = 8.666
EFFECTIVE AREA(ACRES) = 6.26 AREA-AVERAGED Fm(INCH/HR) = 0.06 AREA-AVERAGED Fp(INCH/HR) = 0.20 AREA-AVERAGED Ap = 0.30 TOTAL AREA(ACRES) = 7.5
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 110.00 = 1157.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 110.00 TO NODE 115.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 342.00 DOWNSTREAM(FEET) = 341.40 FLOW LENGTH(FEET) = 57.00 MANNING'S N = 0.012
DEPTH OF FLOW IN 24.0 INCH PIPE IS 16.3 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.68
ESTIMATED PIPE DIAMETER(INCH) = 24.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 19.75
PIPE TRAVEL TIME(MIN.) = 0.11 Tc(MIN.) = 8.78
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 115.00 = 1214.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 115.00 TO NODE 115.00 IS CODE = 81 ---------------------------------------------------------------------------- >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================ MAINLINE Tc(MIN.) = 8.78
* 25 YEAR RAINFALL INTENSITY(INCH/HR) = 3.508
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN APARTMENTS D 0.42 0.20 0.200 75 SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.20
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.200
SUBAREA AREA(ACRES) = 0.42 SUBAREA RUNOFF(CFS) = 1.31
EFFECTIVE AREA(ACRES) = 6.68 AREA-AVERAGED Fm(INCH/HR) = 0.06 AREA-AVERAGED Fp(INCH/HR) = 0.20 AREA-AVERAGED Ap = 0.29 TOTAL AREA(ACRES) = 7.9 PEAK FLOW RATE(CFS) = 20.75
**************************************************************************** 1181
19 FLOW PROCESS FROM NODE 115.00 TO NODE 120.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 341.40 DOWNSTREAM(FEET) = 341.00 FLOW LENGTH(FEET) = 45.00 MANNING'S N = 0.012
DEPTH OF FLOW IN 24.0 INCH PIPE IS 18.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.13
ESTIMATED PIPE DIAMETER(INCH) = 24.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 20.75
PIPE TRAVEL TIME(MIN.) = 0.09 Tc(MIN.) = 8.87
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 120.00 = 1259.00 FEET. ============================================================================ END OF STUDY SUMMARY:

TOTAL AREA(ACRES) = 7.9 TC(MIN.) = 8.87
EFFECTIVE AREA(ACRES) = 6.68 AREA-AVERAGED Fm(INCH/HR)= 0.06 AREA-AVERAGED Fp(INCH/HR) = 0.20 AREA-AVERAGED Ap = 0.292 PEAK FLOW RATE(CFS) = 20.75
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 19.24 7.07 3.966 0.20( 0.06) 0.29 5.4 210.00 2 20.75 8.87 3.488 0.20( 0.06) 0.29 6.7 502.00 3 20.27 10.55 3.160 0.20( 0.06) 0.30 7.2 400.00 4 19.99 11.51 3.009 0.20( 0.06) 0.31 7.5 500.00 5 19.75 12.40 2.885 0.20( 0.06) 0.31 7.7 300.00 6 19.50 13.11 2.795 0.20( 0.06) 0.31 7.9 200.00 7 18.88 13.93 2.701 0.20( 0.06) 0.32 7.9 100.00 ============================================================================ ============================================================================

END OF RATIONAL METHOD ANALYSIS
1182
Proactive Engineering City of Aliso Viejo

APPENDIX C
Unit Hydrograph

1183
Proactive Engineering City of Aliso Viejo
C.1

EXISTING LOSS CALCULATIONS

1184
100 50 25 10 5 2 10 25 100
HC
II I III 4.49 4.03 3.68 3.03 2.12 1.44 3.68 4.49 5.63 > 5 5 2 all

1.40 D Open Brush 83 67 96 0.85 0.80 0.77 0.68 0.51 0.34 0.77 0.85 1.28 1.00 0.20 0.420 0.700 0.840 0.2806.03 D Commercial 75 57 91 5.42 5.36 5.32 5.21 4.97 4.66 5.32 5.42 5.69 0.10 0.20 0.181 0.302 0.362 0.1217.43 0.157 0.170 0.182 0.208 0.262 0.327 0.182 0.157 0.062 0.081 0.135 0.162 0.054 EV
maximum loss rate, Fm
{in/h}
P24 (Inches)
high confidence {HC}
Orange County Precipitation Loss Calculations
Shea - Aliso Existing
Ap Fp
low loss fraction (1-Y) for selected year-storm frequencies area
{acres}
land
use
soil
typesubarea
curve number
CN
AMC
expected value {EV}
year-storm frequency
1185
Proactive Engineering City of Aliso Viejo
C.2
EXISTING 25 YEAR UNIT HYDROGRAPH

1186
EXISTING 25 YEAR UNIT HYDROGRAPH
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 7.43
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.054
LOW LOSS FRACTION = 0.157
TIME OF CONCENTRATION(MIN.) = 12.46

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 25
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.40
30-MINUTE POINT RAINFALL VALUE(INCHES) = 0.87
1-HOUR POINT RAINFALL VALUE(INCHES) = 1.15
3-HOUR POINT RAINFALL VALUE(INCHES) = 1.94
6-HOUR POINT RAINFALL VALUE(INCHES) = 2.71
24-HOUR POINT RAINFALL VALUE(INCHES) = 4.49
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 2.17
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.61
**************************************************************************** TIME VOLUME Q 0. 5.0 10.0 15.0 20.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.01 0.0000 0.00 Q . . . .

0.22 0.0033 0.38 Q . . . .

0.42 0.0099 0.39 Q . . . .

0.63 0.0166 0.39 Q . . . .

0.84 0.0234 0.40 Q . . . .

1.05 0.0302 0.40 Q . . . .

1.26 0.0370 0.40 Q . . . .

1.46 0.0440 0.40 Q . . . .

1.67 0.0509 0.41 Q . . . .
1187

1.88 0.0580 0.41 Q . . . .

2.09 0.0651 0.42 Q . . . .

2.29 0.0723 0.42 Q . . . .

2.50 0.0795 0.43 Q . . . .

2.71 0.0869 0.43 Q . . . .

2.92 0.0943 0.43 Q . . . .

3.12 0.1017 0.44 Q . . . .

3.33 0.1093 0.44 Q . . . .

3.54 0.1169 0.45 Q . . . .

3.75 0.1246 0.45 Q . . . .

3.96 0.1324 0.46 Q . . . .

4.16 0.1402 0.46 Q . . . .

4.37 0.1482 0.47 Q . . . .

4.58 0.1562 0.47 Q . . . .

4.79 0.1644 0.48 Q . . . .

4.99 0.1726 0.48 Q . . . .

5.20 0.1809 0.49 Q . . . .

5.41 0.1894 0.50 Q . . . .

5.62 0.1979 0.50 Q . . . .

5.82 0.2065 0.51 .Q . . . .

6.03 0.2153 0.51 .Q . . . .

6.24 0.2242 0.52 .Q . . . .

6.45 0.2332 0.53 .Q . . . .

6.65 0.2423 0.54 .Q . . . .

6.86 0.2515 0.54 .Q . . . .

7.07 0.2609 0.55 .Q . . . .

7.28 0.2704 0.56 .Q . . . .

7.49 0.2800 0.57 .Q . . . .

7.69 0.2898 0.57 .Q . . . .

7.90 0.2998 0.59 .Q . . . .

8.11 0.3099 0.59 .Q . . . .

8.32 0.3202 0.61 .Q . . . .

8.52 0.3306 0.61 .Q . . . .

8.73 0.3412 0.63 .Q . . . .

8.94 0.3521 0.63 .Q . . . .

9.15 0.3631 0.65 .Q . . . .

9.35 0.3743 0.66 .Q . . . .

9.56 0.3858 0.68 .Q . . . .
1188

9.77 0.3974 0.69 .Q . . . .

9.98 0.4094 0.70 .Q . . . .

10.19 0.4216 0.71 .Q . . . .

10.39 0.4340 0.74 .Q . . . .

10.60 0.4467 0.75 .Q . . . .

10.81 0.4598 0.77 .Q . . . .

11.02 0.4732 0.79 .Q . . . .

11.22 0.4869 0.81 .Q . . . .

11.43 0.5010 0.83 .Q . . . .

11.64 0.5155 0.86 .Q . . . .

11.85 0.5304 0.88 .Q . . . .

12.05 0.5458 0.92 .Q . . . .

12.26 0.5640 1.20 . Q . . . .

12.47 0.5853 1.28 . Q . . . .

12.68 0.6076 1.31 . Q . . . .

12.88 0.6305 1.37 . Q . . . .

13.09 0.6543 1.40 . Q . . . .

13.30 0.6788 1.47 . Q . . . .

13.51 0.7044 1.51 . Q . . . .

13.72 0.7309 1.59 . Q . . . .

13.92 0.7587 1.64 . Q . . . .

14.13 0.7877 1.74 . Q . . . .

14.34 0.8181 1.80 . Q . . . .

14.55 0.8504 1.96 . Q . . . .

14.75 0.8850 2.07 . Q . . . .

14.96 0.9230 2.36 . Q . . . .

15.17 0.9650 2.54 . Q . . . .

15.38 1.0131 3.06 . Q . . . .

15.58 1.0648 2.97 . Q . . . .

15.79 1.1281 4.40 . Q . . . .

16.00 1.2203 6.35 . . Q . . .

16.21 1.4359 18.78 . . . . Q .

16.42 1.6262 3.40 . Q . . . .

16.62 1.6791 2.77 . Q . . . .

16.83 1.7218 2.20 . Q . . . .

17.04 1.7568 1.87 . Q . . . .

17.25 1.7874 1.70 . Q . . . .

17.45 1.8152 1.55 . Q . . . .
1189

17.66 1.8408 1.43 . Q . . . .

17.87 1.8645 1.34 . Q . . . .

18.08 1.8868 1.26 . Q . . . .

18.28 1.9053 0.90 .Q . . . .

18.49 1.9202 0.84 .Q . . . .

18.70 1.9343 0.80 .Q . . . .

18.91 1.9477 0.76 .Q . . . .

19.11 1.9605 0.73 .Q . . . .

19.32 1.9726 0.69 .Q . . . .

19.53 1.9843 0.67 .Q . . . .

19.74 1.9956 0.64 .Q . . . .

19.95 2.0064 0.62 .Q . . . .

20.15 2.0169 0.60 .Q . . . .

20.36 2.0270 0.58 .Q . . . .

20.57 2.0368 0.56 .Q . . . .

20.78 2.0463 0.55 .Q . . . .

20.98 2.0555 0.53 .Q . . . .

21.19 2.0645 0.52 .Q . . . .

21.40 2.0732 0.50 .Q . . . .

21.61 2.0818 0.49 Q . . . .

21.81 2.0901 0.48 Q . . . .

22.02 2.0983 0.47 Q . . . .

22.23 2.1062 0.46 Q . . . .

22.44 2.1140 0.45 Q . . . .

22.65 2.1216 0.44 Q . . . .

22.85 2.1291 0.43 Q . . . .

23.06 2.1364 0.42 Q . . . .

23.27 2.1436 0.41 Q . . . .

23.48 2.1506 0.41 Q . . . .

23.68 2.1576 0.40 Q . . . .

23.89 2.1644 0.39 Q . . . .

24.10 2.1711 0.39 Q . . . .

24.31 2.1744 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
1190
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1445.4
10% 149.5
20% 37.4
30% 24.9
40% 12.5
50% 12.5
60% 12.5
70% 12.5
80% 12.5
90% 12.5
1191
Proactive Engineering City of Aliso Viejo
C.3

PROPSED LOSS CALCULATIONS

1192
100 50 25 10 5 2 10 25 100
HC
II I III 4.49 4.03 3.68 3.03 2.12 1.44 3.68 4.49 5.63 > 5 5 2 all

1.14 D Open Brush 83 67 96 0.69 0.65 0.62 0.55 0.42 0.27 0.62 0.69 1.04 1.00 0.20 0.342 0.570 0.684 0.2286.78 D Apartments 75 57 91 5.76 5.68 5.61 5.45 5.13 4.74 5.61 5.76 6.30 0.20 0.20 0.407 0.678 0.814 0.2717.92 0.186 0.201 0.213 0.242 0.300 0.367 0.213 0.186 0.073 0.095 0.158 0.189 0.063 Orange County Precipitation Loss Calculations
Shea - Aliso Proposed
area
{acres} subarea
soil
type
land
use
curve number
CN
low loss fraction (1-Y) for selected year-storm frequencies Ap Fp
maximum loss rate, Fm
{in/h} expected value {EV} high confidence {HC}
year-storm frequency
AMC P24 (Inches) EV
1193
Proactive Engineering City of Aliso Viejo
C.4
PROPOSED 25 YEAR HYDROGRAPH
1194
PROPOSED 25 YEAR UNIT HYDROGRAPH
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 7.92
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.063
LOW LOSS FRACTION = 0.186
TIME OF CONCENTRATION(MIN.) = 8.87

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 25
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.40
30-MINUTE POINT RAINFALL VALUE(INCHES) = 0.87
1-HOUR POINT RAINFALL VALUE(INCHES) = 1.15
3-HOUR POINT RAINFALL VALUE(INCHES) = 1.94
6-HOUR POINT RAINFALL VALUE(INCHES) = 2.71
24-HOUR POINT RAINFALL VALUE(INCHES) = 4.49
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 2.26
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.71
**************************************************************************** TIME VOLUME Q 0. 7.5 15.0 22.5 30.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.03 0.0000 0.00 Q . . . .

0.18 0.0024 0.40 Q . . . .

0.33 0.0073 0.40 Q . . . .

0.48 0.0122 0.40 Q . . . .

0.63 0.0171 0.40 Q . . . .

0.77 0.0220 0.41 Q . . . .

0.92 0.0270 0.41 Q . . . .

1.07 0.0320 0.41 Q . . . .

1.22 0.0370 0.41 Q . . . .

1.36 0.0421 0.42 Q . . . .
1195

1.51 0.0472 0.42 Q . . . .

1.66 0.0523 0.42 Q . . . .

1.81 0.0575 0.42 Q . . . .

1.96 0.0627 0.43 Q . . . .

2.10 0.0679 0.43 Q . . . .

2.25 0.0732 0.43 Q . . . .

2.40 0.0785 0.44 Q . . . .

2.55 0.0839 0.44 Q . . . .

2.70 0.0893 0.44 Q . . . .

2.84 0.0947 0.45 Q . . . .

2.99 0.1001 0.45 Q . . . .

3.14 0.1056 0.45 Q . . . .

3.29 0.1112 0.45 Q . . . .

3.43 0.1167 0.46 Q . . . .

3.58 0.1224 0.46 Q . . . .

3.73 0.1280 0.47 Q . . . .

3.88 0.1337 0.47 Q . . . .

4.03 0.1395 0.47 Q . . . .

4.17 0.1453 0.48 Q . . . .

4.32 0.1511 0.48 Q . . . .

4.47 0.1570 0.48 Q . . . .

4.62 0.1629 0.49 Q . . . .

4.76 0.1689 0.49 Q . . . .

4.91 0.1749 0.50 Q . . . .

5.06 0.1810 0.50 Q . . . .

5.21 0.1871 0.50 Q . . . .

5.36 0.1933 0.51 Q . . . .

5.50 0.1996 0.51 Q . . . .

5.65 0.2059 0.52 Q . . . .

5.80 0.2122 0.52 Q . . . .

5.95 0.2186 0.53 Q . . . .

6.10 0.2251 0.53 Q . . . .

6.24 0.2316 0.54 Q . . . .

6.39 0.2382 0.54 Q . . . .

6.54 0.2449 0.55 Q . . . .

6.69 0.2516 0.55 Q . . . .

6.83 0.2584 0.56 Q . . . .

6.98 0.2653 0.57 Q . . . .
1196

7.13 0.2722 0.57 Q . . . .

7.28 0.2792 0.58 Q . . . .

7.43 0.2863 0.58 Q . . . .

7.57 0.2934 0.59 Q . . . .

7.72 0.3007 0.59 Q . . . .

7.87 0.3080 0.60 Q . . . .

8.02 0.3154 0.61 Q . . . .

8.16 0.3229 0.62 Q . . . .

8.31 0.3304 0.62 Q . . . .

8.46 0.3381 0.63 Q . . . .

8.61 0.3459 0.64 Q . . . .

8.76 0.3537 0.65 Q . . . .

8.90 0.3617 0.65 Q . . . .

9.05 0.3698 0.67 Q . . . .

9.20 0.3779 0.67 Q . . . .

9.35 0.3862 0.68 Q . . . .

9.50 0.3946 0.69 Q . . . .

9.64 0.4031 0.70 Q . . . .

9.79 0.4118 0.71 Q . . . .

9.94 0.4206 0.73 Q . . . .

10.09 0.4295 0.73 Q . . . .

10.23 0.4385 0.75 Q . . . .

10.38 0.4477 0.76 .Q . . . .

10.53 0.4571 0.77 .Q . . . .

10.68 0.4666 0.78 .Q . . . .

10.83 0.4762 0.80 .Q . . . .

10.97 0.4861 0.81 .Q . . . .

11.12 0.4961 0.83 .Q . . . .

11.27 0.5063 0.84 .Q . . . .

11.42 0.5167 0.86 .Q . . . .

11.57 0.5273 0.88 .Q . . . .

11.71 0.5382 0.90 .Q . . . .

11.86 0.5493 0.91 .Q . . . .

12.01 0.5606 0.94 .Q . . . .

12.16 0.5733 1.14 .Q . . . .

12.30 0.5882 1.30 .Q . . . .

12.45 0.6042 1.32 .Q . . . .

12.60 0.6205 1.35 .Q . . . .
1197

12.75 0.6371 1.37 .Q . . . .

12.90 0.6542 1.42 .Q . . . .

13.04 0.6717 1.44 .Q . . . .

13.19 0.6896 1.49 .Q . . . .

13.34 0.7080 1.52 . Q . . . .

13.49 0.7269 1.58 . Q . . . .

13.63 0.7463 1.61 . Q . . . .

13.78 0.7664 1.68 . Q . . . .

13.93 0.7871 1.72 . Q . . . .

14.08 0.8085 1.79 . Q . . . .

14.23 0.8306 1.82 . Q . . . .

14.37 0.8536 1.93 . Q . . . .

14.52 0.8775 2.00 . Q . . . .

14.67 0.9030 2.17 . Q . . . .

14.82 0.9301 2.27 . Q . . . .

14.97 0.9592 2.51 . Q . . . .

15.11 0.9907 2.65 . Q . . . .

15.26 1.0254 3.01 . Q . . . .

15.41 1.0636 3.25 . Q . . . .

15.56 1.1036 3.29 . Q . . . .

15.70 1.1467 3.77 . Q . . . .

15.85 1.2062 5.97 . Q . . . .

16.00 1.2929 8.22 . Q . . .

16.15 1.4915 24.28 . . . . Q .

16.30 1.6679 4.61 . Q . . . .

16.44 1.7149 3.07 . Q . . . .

16.59 1.7509 2.82 . Q . . . .

16.74 1.7826 2.38 . Q . . . .

16.89 1.8098 2.08 . Q . . . .

17.03 1.8340 1.87 . Q . . . .

17.18 1.8562 1.76 . Q . . . .

17.33 1.8769 1.64 . Q . . . .

17.48 1.8964 1.55 . Q . . . .

17.63 1.9148 1.47 .Q . . . .

17.77 1.9323 1.40 .Q . . . .

17.92 1.9490 1.34 .Q . . . .

18.07 1.9649 1.28 .Q . . . .

18.22 1.9784 0.93 .Q . . . .
1198

18.37 1.9895 0.89 .Q . . . .

18.51 2.0001 0.85 .Q . . . .

18.66 2.0104 0.82 .Q . . . .

18.81 2.0202 0.79 .Q . . . .

18.96 2.0297 0.76 .Q . . . .

19.10 2.0389 0.74 Q . . . .

19.25 2.0478 0.72 Q . . . .

19.40 2.0565 0.70 Q . . . .

19.55 2.0649 0.68 Q . . . .

19.70 2.0730 0.66 Q . . . .

19.84 2.0810 0.64 Q . . . .

19.99 2.0888 0.63 Q . . . .

20.14 2.0963 0.61 Q . . . .

20.29 2.1037 0.60 Q . . . .

20.43 2.1110 0.59 Q . . . .

20.58 2.1181 0.57 Q . . . .

20.73 2.1250 0.56 Q . . . .

20.88 2.1318 0.55 Q . . . .

21.03 2.1384 0.54 Q . . . .

21.17 2.1450 0.53 Q . . . .

21.32 2.1514 0.52 Q . . . .

21.47 2.1577 0.51 Q . . . .

21.62 2.1639 0.50 Q . . . .

21.77 2.1700 0.49 Q . . . .

21.91 2.1759 0.49 Q . . . .

22.06 2.1818 0.48 Q . . . .

22.21 2.1876 0.47 Q . . . .

22.36 2.1933 0.46 Q . . . .

22.50 2.1989 0.46 Q . . . .

22.65 2.2045 0.45 Q . . . .

22.80 2.2099 0.44 Q . . . .

22.95 2.2153 0.44 Q . . . .

23.10 2.2206 0.43 Q . . . .

23.24 2.2259 0.43 Q . . . .

23.39 2.2310 0.42 Q . . . .

23.54 2.2361 0.41 Q . . . .

23.69 2.2412 0.41 Q . . . .

23.84 2.2461 0.40 Q . . . .
1199

23.98 2.2510 0.40 Q . . . .

24.13 2.2559 0.40 Q . . . .

24.28 2.2583 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1445.8
10% 106.4
20% 26.6
30% 17.7
40% 8.9
50% 8.9
60% 8.9
70% 8.9
80% 8.9
90% 8.9
1200
Proactive Engineering City of Aliso Viejo

APPENDIX D
Orifice Calculations
1201
Q 18.8 cfs
Cd 0.6 0.6 is conservative
h1 1.75 ft upstream WSE above orfice centroid
h2 1.25 downstream WSE above orifice centroid
g 32.2 ft/s2
A 5.52 sf
d 2.65 ft
Orifice Design (Submerged)
Using trial and error we get to this solution, where the diameter of the orifice is roughly the size of the downstream pipe. In the submerged orifice situation the downstream 30" pipe acts as an orifice restricting the flow to the existing conditon. This will be further proved during final design. We will model the hydraulic grade line and balance that with the orifice size. d=
1202
Appendix H:

Water Quality Management Plan
1203
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo
SHEA HOMES Owner’s Certification
Water Quality
Management Plan
(WQMP)
Project Name:

Shea – Aliso Viejo
Prepared for:

Shea Homes
15261 Laguna Canyon Rd, Suite 100
Irvine, CA 92618
(949) 526-8800
Prepared by:

Proactive Engineering
Engineer: Amy Jaramillo
Registration No. 94608
27051 Towne Centre Dr, Suite 270
Foothill Ranch, CA 92610
(949) 716-7460
Engineer’s Seal
Prepared on:

PC #1 June 30, 2025
PC #2 October 14, 2025
PC #3 January 9, 2026
12, 2026
1204
Project Owner’s Certification
Permit/Application No. TBD Grading Permit No. TBD
Tract/Parcel Map No. TBD Building Permit No. TBD
CUP, SUP, and/or APN (Specify Lot Numbers if Portions of Tract) APN 623-124-08 This Water Quality Management Plan (WQMP) has been prepared for Shea Homes by Proactive Engineering. The WQMP is intended to comply with the requirements of the local NPDES Stormwater Program requiring the preparation of the plan.

The undersigned, while it owns the subject property, is responsible for the implementation of the provisions of this plan and will ensure that this plan is amended as appropriate to reflect up-to-date conditions on the site consistent with the current Orange County Drainage Area Management Plan (DAMP) and the intent of the non-point source NPDES Permit for Waste Discharge Requirements for the County of Orange, Orange County Flood Control District and the incorporated Cities of Orange County within the San Diego Region (South Orange County).

Once the undersigned transfers its interest in the property, its successors-in-interest shall bear the aforementioned responsibility to implement and amend the WQMP. An appropriate number of approved and signed copies of this document shall be available on the subject site in perpetuity.

Owner:

Title
Company Shea Homes
Address 15261 Laguna Canyon Rd, Suite 100 Irvine, CA 92618 Email
Telephone # 949-526-8800
Signature Date 3/9/26
Director of Forward Planning
[email protected]
Shea Homes Limited Partnership (Attn: Emilie Simard)
c~s~ I 1
1205
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 1

Page 3 ends

Contents Page No.

Section 1 Discretionary Permit(s) and Water Quality Conditions ...................... 5 Section 2 Project Description ........................................................................... 6

2.1 General Description ............................................................................ 6

2.3 Property Ownership/Management .................................................... 7 Section 3 Site & Watershed Characterization ................................................... 8

3.1 Site Conditions .................................................................................... 8

3.1.1 Existing Site Conditions ...................................................................................... 8

3.1.2 Infiltration-Related Characteristics ................................................................... 8

3.2 Proposed Site Development Activities ............................................. 9

3.2.1 Overview of Site Development Activities ..................................................... 9

3.2.2 Project Attributes Influencing Stormwater Management.......................... 9

3.2.3 Effects on Infiltration and Harvest and Use Feasibility ............................ 10

3.3 Receiving Waterbodies ...................................................................... 10

3.4 Stormwater Pollutants or Conditions of Concern ........................... 11

3.5 Hydrologic Conditions of Concern ..................................................... 11

3.6 Critical Course Sediment Yield Areas .............................................. 12 Section 4 Site Plan and Drainage Plan ............................................................ 13

4.1 Drainage Management Area Delineation ........................................ 13

4.2 Overall Site Design BMPs .................................................................. 13

4.3 DMA Characteristics and Site Design BMPs .................................... 13

4.3.1 DMA Summary ............................................................................................ 14

4.4 Source Control BMPs ......................................................................... 16 Section 5 Low Impact Development BMPs ..................................................... 20

5.1 LID BMPs ............................................................................................. 20

5.1.1 Hydrologic Source Controls .............................................................................. 20

5.1.2 Structural LID BMP ........................................................................................... 21 Section 6 Hydromodification BMPs ................................................................ 23

6.1 Points of Compliance ......................................................................... 23

6.2 Pre-Development (Natural) Conditions .......................................... 23

6.3 Post-Development Conditions and Hydromodification BMPs ...... 23

6.4 Measures for Avoidance of Critical Coarse Sediment Yield Areas 23

6.5 Hydrologic Modeling and Hydromodification Compliance ............ 23 Section 7 Educational Materials Index ........................................................... 25 Attachment A: WQMP Site Plan ........................................................................ 26 Attachment B: BMP Calculations ...................................................................... 27 Attachment C: Educational Materials ............................................................... 28 Attachment D: Operations and Maintenance Plan ............................................... 29 1206
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 1

Page 4 ends

Attachment E: Geotechnical Report ..................................................................... 30 Attachment F: SOCHM Model .............................................................................. 31 1207
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 1

Page 5 ends

Section 1 Discretionary Permit(s) and Water
Quality Conditions
Project Infomation
Permit/Application No. TBD
Site Address or
Tract/Parcel Map
No.

APN 632-124-08
Additional Information/
Comments:

Parcel 1 of Parcel Map No. 93-196
Water Quality Conditions
Water Quality
Conditions from prior
approvals or applicable
watershed-based plans
TBD – none currently.
1208
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 2

Page 6 ends

Section 2 Project Description

2.1 General Description
Description of Proposed Project
Site Location
The project is located at 2718 Aliso Creek Rd in Aliso Viejo. APN 632-124-

08. Parcel 1 of Parcel Map No. 93-196. The project borders Pacific Park Dr, Journey and Aliso Creek Rd.

Project Area (ft2): 367,650 Number of Dwelling Units: 137 SIC Code: 1522 Narrative Project
Description:

The project proposes the redevelopment of three existing commercial office buildings and associated parking lots into 137 town home and garden court condos with associated private streets, wet and dry utilities, landscaping, rec center and amenities.

Project Area
Pervious Impervious
Area
(acres or sq ft)
Percentage
Area
(acres or sq ft)
Percentage
Pre-Project Conditions 2.0 acres 24% 6.5 acres 76%
Post-Project Conditions 3.2 acres 38% 5.3 acres 62%
1209
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 2

Page 7 ends

2.2 Post Development Drainage Characteristics
The site drains from all directions to a low point on the eastern edge. Onsite catch basins, inlets and private storm drain pipes connect to an existing 30” RCP that traverses the adjacent property (APN:
631-124-07). The western edge of the property is an existing landscaped 2:1 slope that will primarily remain untouched. The runoff from the slopes is picked up by a series of v-ditches and downdrains which in turn will tie into the private on-site storm drain system.

2.3 Property Ownership/Management
The proposed project consists of for-sale condominium units. Homeowners will only own the airspace within their unit. Everything outside of the condominium air-space will be owned and maintained by a homeowner’s association (HOA) created specifically for this development.

Mainline sewer and water will be publicly owned and maintained by Moulton Niguel Water District. The HOA will be responsible for maintenance of all the common areas within the development including the amenities, streets and proposed storm water facilities. 1210
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 3

Page 8 ends

Section 3 Site & Watershed Characterization

3.1 Site Conditions

3.1.1 Existing Site Conditions
The existing property contains three two-story office buildings and surface parking. These areas are fairly flat, with a slope between 1-3%. The western edge of the property is an existing landscaped 2:1 slope. The runoff from the slopes is picked up by a series of v-ditches and downdrains which in turn tie into the private on-site storm drain system. There are a series of onsite inlets that take the site surface drainage and run it to the point of connection at the eastern edge. The flows continue into a 30” RCP that runs through the adjacent property (APN 632-124-07).

Existing Land Uses
Land Use Description Total Area
(acres)
Impervious
Area
(acres)
Pervious Area
(acres)
Imperviousness
(%)
Office Buildings &
Parking

6.5 6.5 0.0 100%
Landscaped Slopes 2.0 0.0 2.0 0%
Total 8.5 6.5 2.0 76%

3.1.2 Infiltration-Related Characteristics

3.1.2.1 Hydrogeologic Conditions
Groundwater is not anticipated to be encountered during grading on construction. Given this is a redevelopment, the likelihood of groundwater is even lower.

3.1.2.2 Soil and Geologic Infiltration Characteristics
The entire site consists of soil type “D”
Based on the NMG due diligence report “due to the conditions of compacted fill over bedrock the subject site is not considered feasible for infiltration.”

3.1.2.3 Geotechnical Conditions
Based on NMG’s initial exploration the following conditions exist on the project site:
• Variable soil conditions with moisture contents from 2-35% • Expansion potential very low to low, with the possibility of higher expansive soils during demo and grading
1211
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 3

Page 9 ends

• 2:1 existing slopes on the western edge to remain

3.1.2.4 Summary of Infiltration Opportunities and Constraints of Existing Site Due to the nature of a redevelopment site and the soil type D infiltration does not seem feasible on the project site.

3.2 Proposed Site Development Activities

3.2.1 Overview of Site Development Activities
The project proposes the redevelopment of three existing commercial office buildings and associated parking lots into 137 town home and garden court condos. The overall drainage pattern will be very similar, still draining to the east and connecting to the existing offsite 30” RCP. The western landscaped slopes will primarily stay untouched. The grades along the boundaries will not significantly change. The streets will drain at approximately 0.7-2.0% across the site.

3.2.2 Project Attributes Influencing Stormwater Management • Potential pollutant generating activities are those typical of residential developments.

Possible sources include fertilizers from improperly managed landscape areas, pet waste, improper homeowner disposal of trash and debris, uncovered on-street parking and dry weather flows such as irrigation overspray and car washing activities. • Proposed buildings are condos, attached townhomes/garden courts for single family dwelling. There will be a recreation building for community use at the center of the site. • The majority of the landscaping will be the 2:1 slopes along the western edge of the property which will remain primarily untouched. Additional landscape areas between the garden courts and the town homes will be maintained by the HOA. • Existing drainage patterns will be largely unchanged with the site flowing from the north/south and west to the east. Cut/fill in any area will not be substantial. The streets will slope primarily at 1%.
• Land uses include areas of residential development and HOA maintained 2:1 landscaped slopes.
1212
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 3

Page 10 ends

Proposed Land Uses
Land Use Description Total Area
(acres)
Impervious
Area (acres)
Pervious Area
(acres)
Imperviousness
(%)
Residential Development 6.9 5.3 1.6 77%
Landscaped Slopes 1.6 0.0 1.6 0%
Total 8.5 5.3 3.2 62%

3.2.3 Effects on Infiltration and Harvest and Use Feasibility Due to the nature of redevelopment and compacted fills over bedrock infiltration is not feasible onsite. The irrigation demands are not great enough to implement harvest and use.

3.3 Receiving Waterbodies
The project drainage is collected by a series of onsite inlets and private storm drain which eventually connects to an existing 30” RCP at the eastern boundary of the site. The 30” RCP runs through the adjacent parcel (existing gas station at the corner of Aliso Creek and Pacific Park). From there the storm drain connects to a catch basin in Aliso Creek Rd and in turn enters an existing 42” RCP in Aliso Creek. That pipe joins an existing 72” RCP in Pacific Park which continues down Woodfield. Along Woodfield the pipe upsizes to a 96” RCP and eventually outlets into Aliso Creek Channel. The drainage flows along Aliso Creek Channel, through Aliso Creek (mouth) to the Pacific Ocean Shoreline at Aliso Creek Mouth. The following are the 303(d) listings for the drainage:
• Aliso Creek
o Benthic Community Effects (125926)
o Indicator Bacteria (79858)
o Malathion (81901)
o Nitrogen (127601)
o Phosphorus (111092)
o Selenium (111093)
o Toxicity (111095)
• Aliso Creek (mouth)
o Indicator Bacteria (70046)
o Toxicity (95760)
• Pacific Ocean Shoreline
o Indicator Bacteria (132167)
o Toxicity (84122)

1213
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo
SHEA HOMES Section 3

Page 11 ends

3.4 Stormwater Pollutants or Conditions of Concern
Pollutants or Conditions of Concern
Pollutant
Expected from
Proposed Land
Uses/Activities
(Yes or No)
Receiving
Waterbody
Impaired
(Yes or No)
Priority
Pollutant
from WQIP
or other
Water
Quality
Condition?
(Yes or No)
Pollutant of
Concern
(Primary, Other,
or No)
Suspended-Solids Yes No No Other
Nutrients Yes Yes No Primary
Heavy Metals No No No No
Bacteria/Virus/Pathogens Yes Yes No Primary
Pesticides Yes No No Other
Oil and Grease Yes No No Other
Toxic Organic
Compounds No Yes No No
Trash and Debris Yes No No Other
Dry Weather Runoff Yes No No Other

3.5 Hydrologic Conditions of Concern
Does a hydrologic condition of concern exist for this project No – An HCOC does not exist for this receiving water because:

Project discharges directly to a protected conveyance (bed and bank are concrete lined the entire way from the point(s) of discharge to a receiving lake, reservoir, embayment, or the Ocean
Project discharges directly to storm drains which discharge directly to a reservoir, lake, embayment, ocean or protected conveyance (as described above) The project discharges to an area identified in the WMAA as exempt from hydromodification concerns
Yes – An HCOC does exist for this receiving water because none of the above are applicable. □
□
□
□
1214
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 3

Page 12 ends

Repeat this checklist for each different receiving water to which the project would discharge.

3.6 Critical Course Sediment Yield Areas
Critical coarse sediment provisions do not apply to redevelopment of an existing developed site. 1215
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 4

Page 13 ends

Section 4 Site Plan and Drainage Plan

4.1 Drainage Management Area Delineation
The WQMP Exhibit contained in this report shows the breakup of the project site into 10 DMA’s.

The site was divided up based on the layout of the inlets onsite. Where possible two inlets will be connected to one BMP in order to reduce the number of BMPs needed.

4.2 Overall Site Design BMPs
Minimize Impervious Area – Common area HOA maintained landscape will be incorporated where feasible on site, in the middle of the garden court units, between the townhome buildings, around the entries and rec center.

Maximize Natural Infiltration Capacity – Landscape areas have been provided for incidental infiltration and evapotranspiration.

Preserve Existing Drainage Patterns and Time of Concentration – the project follows the existing drainage pattern and Tc as much as possible. The western edge 2:1 slopes are the further reaches of the flow path and travel through onsite storm drain pipes to the existing point of connection on the eastern side.

Disconnect Impervious Areas - Landscaping will be provided throughout the project to minimize the amount of directly connected impervious areas.

Protect Existing Vegetation and Sensitive Areas – Existing slopes will be maintained and protected. No sensitive areas.

Revegetate Disturbed Areas – slopes that are impacted will be replanted.

Soil Stockpiling and Site Generated Organics - The site earthwork is expected to balance. If stockpiling is necessary, then proper stockpiling, storage, and reapplication of disturbed topsoil is recommended. Proper stockpiling generally includes protecting the stockpile to prevent excessive compaction and covering the stockpile to prevent significant erosion and leaching of nutrients.

Firescaping - Correct zone plant selection and spacing will be integrated Water Efficient Landscaping - Efficient irrigation and drought tolerant plants will be integrated Slopes and Channel Buffers – Existing 2:1 slopes will be protected and maintained. Existing vditches will be utilized and will be tied into the onsite storm drain.

4.3 DMA Characteristics and Site Design BMPs
The site is broken up into 14 different DMA’s. See summary table below for the individual areas. 1216
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo
SHEA HOMES Section 4

Page 14 ends

4.3.1 DMA Summary
Drainage Management Areas
DMA
(Number/Description)
Total
Area
(acres)
Imperviousness
(%)
Infiltration
Feasibility
Category
(Full, Partial, or No
Infiltration)
Hydrologic Source
Controls Used
A1 0.49 37% No Infiltration Impervious area
dispersion
A2 0.25 17% No Infiltration Impervious area
dispersion
B1 0.44 35% No Infiltration Impervious area
dispersion
B2 0.38 28% No Infiltration
Impervious area
dispersion
C1 0.83 66% No Infiltration Impervious area
dispersion
C2 0.12 8% No Infiltration Impervious area
dispersion
D1 0.35 26% No Infiltration Impervious area
dispersion
D2 0.05 4% No Infiltration Impervious area
dispersion
E 0.51 34% No Infiltration Impervious area
dispersion
F 0.95 73% No Infiltration Impervious area
dispersion
G 0.93 76% No Infiltration Impervious area
dispersion
H 0.29 24% No Infiltration Impervious area
dispersion
D
D
D
D
D
D
D
D
D
D
D
D
1217
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo
SHEA HOMES Section 4

Page 15 ends

I 0.42 31% No Infiltration Impervious area
dispersion
J 0.76 66% No Infiltration Impervious area
dispersion
D I
1218
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo
SHEA HOMES Section 4

Page 16 ends

4.4 Source Control BMPs
Non-Structural Source Control BMPs
Identifier Name
Check One
Reason Source Control is
Not Applicable Included Not
Applicable
N1 Education for Property Owners,
Tenants and Occupants
N2 Activity Restrictions
N3 Common Area Landscape
Management
N4 BMP Maintenance
N5 Title 22 CCR Compliance (How
development will comply) No hazardous waste on-site
N6 Local Industrial Permit Compliance Not an industrial project N7 Spill Contingency Plan No hazardous waste on-site
N8 Underground Storage Tank
Compliance
No underground storage tanks
on-site
N9 Hazardous Materials Disclosure
Compliance
No hazardous waste on-site
N10 Uniform Fire Code Implementation No toxic gases on-site N11 Common Area Litter Control
N12
Employee Training
No employees for residential
development
N13 Housekeeping of Loading Docks No loading docks on-site N14 Common Area Catch Basin Inspection
N15 Street Sweeping Private Streets and
Parking Lots

N16 Retail Gasoline Outlets No retail gasoline on-site
The following is a description of how each non-structural source control BMP will be implemented:

N1 – Education for Property Owners 66%
Educational materials will be provided to homeowners at close of escrow by owner/developer and periodically thereafter by the HOA to inform them of their actions and the potential impacts to downstream water quality. Materials include those described in Section 7 of this WQMP and any updates to educational materials.
b
[8:1 □
............................................................................. ······· l:8J······· ·········o ...................................................... . , .................................................................................................................................................................. . [8:1 □ , .................................................................................................................................................................. . [8:1 □ □ [8:1
······················································································o················~·········································· .................................................................................... o······· ......... l:8J ...................................................... . , .................................................................................................................................................................. . □
□
[8:1
[8:1
.................................................................................... o······· ......... l:8J ...................................................... . , .................................................................................................................................................................. . [8:1 □ □ [8:1
······················································································o················~·········································· ............................................................................. ······· l:8J······· ·········o ...................................................... . [8:1 □
, .................................................................................................................................................................. . □ [8:1 1219
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 4

Page 17 ends

N2 – Activity Restrictions
Activity restrictions to minimize potential impacts to water quality and with the purpose of protecting water quality will be prescribed by the project’s Covenant, Conditions and Restrictions (CC&Rs), or other equally effective measure.

N3 – Common Area Landscape Management
Maintenance activities for landscape areas shall be consistent with City and manufacturer guidelines for fertilizer and pesticide use (OC DAMP Section 5.5). Maintenance includes trimming, weeding and debris removal and vegetation planting and replacement and shall be consistent with the City’s Landscape Ordinance. Stockpiled materials during maintenance activities shall be placed away from drain inlets and runoff conveyance devices. Wastes shall be properly disposed of or recycled.

N4 – BMP Maintenance
The Owner shall be responsible for implementation of each applicable non-structural, structural and LID BMPs as well as scheduling inspection and maintenance cleaning of all applicable structural BMP facilities. The Owner shall be responsible for inspection and maintenance activities in landscape areas.

N11 – Common Area Litter Control
Litter control onsite will include the use of litter patrols, violation reporting and clean up during landscaping maintenance activities and as needed to ensure good housekeeping of the project’s common areas.

N14 – Common Area Catch Basin Inspection
As required by the TGD, at least 80% of all drainage facilities shall be inspected each year and, if necessary, cleaned and maintained prior to the storm season, no later than October 15th each year; with 100% of all drainage facilities inspected, cleaned and maintained within a two-year period.

Drainage facilities include catch basins and inlets, detention vaults and the project’s LID BMPs.

N15 – Street Sweeping Private Streets and Parking Lots
Private streets shall be vacuum swept on a regular basis consistent with the HOA’s schedule. 1220
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo
SHEA HOMES Section 4

Page 18 ends

Structural Source Control BMPs
Identifier Name
Check One
Reason Source Control is Not
Applicable Included Not
Applicable
S1 Provide storm drain system stenciling
and signage
S2
Design and construct outdoor material
storage areas to reduce pollution
introduction
No outdoor storage proposed
S3
Design and construct trash and waste
storage areas to reduce pollution
introduction
No trash enclosures proposed
S4
Use efficient irrigation systems &
landscape design, water conservation,
smart controllers, and source control

S5 Protect slopes and channels and
provide energy dissipation
Incorporate requirements applicable to
individual priority project categories
(from SDRWQCB NPDES Permit)

S6 Dock areas No dock areas proposed
S7 Maintenance bays No maintenance bays proposed
S8 Vehicle wash areas No vehicle wash areas proposed
S9 Outdoor processing areas
No outdoor processing areas
proposed
S10 Equipment wash areas
No equipment wash areas
proposed.

S11 Fueling areas No fueling areas proposed
S12 Hillside landscaping
S13 Wash water control for food
preparation areas No food prep areas proposed
S14 Community car wash racks
No community car wash racks
proposed
The following is a description of how each structural source control BMP will be implemented:

S1 – Provide Storm Drain System Stenciling and Signage (CASQA SD-13) ~ □
□ ~
□ ~
~ □
~ □
□ □
□ ~
□ ~
□ ~
□ ~
□ ~
□ ~
~ □
□ ~
□ ~
1221
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 4

Page 19 ends

Storm drain stenciling with a brief message or graphical icons with symbols, prohibiting the dumping of improper materials into the storm drain system shall be placed in highly visible areas adjacent to all storm drain inlets. The BMP is designed to alert and educate homeowners and guests of the destination of pollutants discharged into storm drain systems. Legibility of stencils and signs shall be maintained.

S4 – Efficient Irrigation System & Landscape Design (CASQA SD-10 & SD-12) Landscaping will be designed to consist of native species or drought tolerant, water conserving landscaping. Irrigation system will be designed, constructed and adjusted to eliminate overspray to hardscape areas, with timing and cycle lengths adjusted in accordance with water demands, given time of year, weather, day or night time temperatures based on system specifications and local climate patterns.

S5 – Protect Slopes & Channels
Existing v-ditches on the western edge slopes will be protected and maintained. Existing landscaping will be maintained and any areas of construction will be replanted to reduce erosion susceptibility.

S12 – Hillside Landscaping (CASQA SD-10)
Hillside areas that are disturbed by project development shall be landscaped with deep-rooted, drought tolerant plant species selected for erosion control, satisfactory to the local permitting authority.
1222
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 5

Page 20 ends

Section 5 Low Impact Development BMPs
The site is broken up into 10 different DMA’s but each is relatively small and contains similar land use and imperviousness. Each area is treated by the same type of BMP’s so a summary of those is contained below.

5.1 LID BMPs
• Infiltration is not feasible due to very low measured infiltration rates (see geotechnical report in Attachment E).
• Harvest and use are not feasible due to insufficient demand o Given the nature of the project is 137 individual town homes with small yards it is infeasible to expect each individual homeowner to harvest and reuse their water. o Alternatively, the HOA maintained landscape areas are spread out throughout the site without a sufficiently large area to capture and reuse. • Bioretention BMPs with partial infiltration are infeasible given the project site’s inability to infiltrate
• Biotreatment BMP’s without infiltration
o Bioretention with Underdrain & Impervious Liner
 In order to use a traditional bioretention system without infiltration we would need to construct an open air basin at the downstream end of the storm drain system. Unfortunately, by the time the storm drain gets to the downstream end it is already significantly deep. Outletting that storm drain at the surface of a basin and allowing for gravity biotreatment would not work to connect to the existing point of connection.

5.1.1 Hydrologic Source Controls
HSC-1 Localized On-Lot Infiltration
On-lot infiltration will not be used. These are multifamily buildings so the downspouts will be tied into the area drain system.

HSC-2 Impervious Area Dispersion
Runoff from the project’s walkway areas will be directed to adjacent landscaping areas for filtration, evapotranspiration and incidental infiltration of runoff and volume reduction, prior to discharging to the storm drain system. This will take place in the rear of the lots, draining to the garden courtyards and the paseo between the townhomes.

HSC-3 Street Trees
Trees will be planted in the common spaces, including the garden courts, paseos between townhomes and along parking area.

HSC-4 Residential Rain Barrels
There is not sufficient irrigation demand to make rain barrels feasible. 1223
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 5

Page 21 ends

HSC-5 Green Roof/Brown Roof
Green/brown roofs are not part of the structural and architectural design at this time.

HSC-6 Self Retaining Areas
None of the DMA’s are self retaining, they all create more runoff than the natural condition.

Note: DCV reduction credit has not been determined for these areas as their benefits are incidental and the areas not specifically designed to retain runoff.

5.1.2 Structural LID BMP
The project site in its existing condition is made up of 3 large office buildings and surface parking lots. The soil on site is compacted fill over siltstone and sandstone and not suitable for infiltration.

Therefore, BMPs designed for full or partial infiltration are not applicable or appropriate.

The project LID selection and sizing criteria is the following, “Third Priority – Biotreatment with Negligible Retention”.

LID BMPs must be implemented that are designed to meet the following criteria:
1) Maximize volume retention through the incorporation of all applicable HSCs.

Note: Due to their more distributed nature, some HSCs may allow incidental volume reduction in marginal conditions where no volume reduction is permissible within LID BMPs.

AND
2) Size biotreatment BMPs to meet one of the following equivalent criteria:
d) Treat 1.5 times the DCV.

OR
e) Treat 80 percent of average annual runoff volume, and apply a multiplier of 1.5 to the resultant required volume and footprint.

OR
f) Design a biofiltration BMP that has a static biofiltration volume (bowl volume plus media pore spaces) of at least 0.75 times the DCV.

NOTE: Option (d) and (e) do not have a specific static storage volume requirement and allow routing to be considered; Option (f) specifies a minimum static storage volume and does not require or allow routing to be considered
The following BMP was selected based on site constraints and infiltration feasibility:

BIO-7: Proprietary Biotreatment, see Attachment G for fact sheet.

The BMP sizing methodology used was based on the “Biotreatment with No Infiltration” category for a proprietary compact biofiltration system. See Worksheet 9: Flow-Based Compact Biofiltration with Supplemental Retention Method for sizing calculations of the biofiltration system.

Biofiltration BMPs are a class of structural BMPs that treat suspended solids and dissolved pollutants in storm water using mechanisms characteristic of biologically active systems. These 1224
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 5

Page 22 ends

BMPs are considered treat and release facilities and include treatment mechanisms that employ soil microbes and plants. To address the project’s pollutants of concern, a proprietary biotreatment BMP by Modular Wetland Systems(MWS) will be utilized with a nutrient sensitive media, which will allow the units to provide a medium to high level of effectiveness at removing the project’s storm water pollutants.

The biofiltration system will include 10 MWS Linear units (one in each DMA). The units will provide decentralized treatment to collect street, common area and roof drain flows. Treated flows will then be conveyed to the main storm drain system for outlet into the existing storm at the eastern edge of the site.
1225
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 6

Page 23 ends

Section 6 Hydromodification BMPs

6.1 Points of Compliance
The entire project site drains to an existing storm drain pipe on the eastern side of the property.

From there the 30” RCP runs through the adjacent parcel (existing gas station at the corner of Aliso Creek and Pacific Park) and then the storm drain connects to a catch basin in Aliso Creek Rd and in turn enters an existing 42” RCP in Aliso Creek Rd. That pipe joins an existing 72” RCP in Pacific Park Dr which continues down Woodfield. Along Woodfield the pipe upsizes to a 96” RCP and eventually outlets into Aliso Creek Channel. The drainage flows along Aliso Creek Channel, through Aliso Creek (mouth) to the Pacific Ocean Shoreline at Aliso Creek Mouth. Aliso Creek Channel, Aliso Creek (mouth) and the Pacific Ocean Shoreline at Aliso Creek Mouth are all considered natural drainage conveyance systems to some extent and therefore cause a hydraulic condition of concern.

6.2 Pre-Development (Natural) Conditions
The site is currently developed with 3 office buildings and surface parking. The western edge is primarily 20-30’ 2:1 landscaped slopes. In the natural (pre-development) condition the site was barren, covered with open brush. The site was naturally composed of steep slopes as noted in the geotechnical report (Attachment E).

6.3 Post-Development Conditions and Hydromodification BMPs In the post-development condition the site is 62% impervious compared to the existing site which is 76% impervious. It can easily be seen that this redevelopment project increases the pervious area by adding landscape space throughout the project.

6.4 Measures for Avoidance of Critical Coarse Sediment Yield Areas
Per WIHMP map, Critical Coarse Sediment Yield Areas are not applicable to this project.

6.5 Hydrologic Modeling and Hydromodification Compliance The South Orange County Hydromodification Management Plan (SOCHM) establishes criteria to ensure that new development and redevelopment projects do not increase downstream erosion, sedimentation, or habitat degradation due to altered stormwater flow. Projects that create or replace one acre or more of impervious surface must evaluate post-project runoff against preproject (natural) conditions. Where feasible, reducing stormwater flows to natural conditions is achieved through on-site retention/detention facilities or other low-impact development (LID) practices.
1226
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Section 6

Page 24 ends

The entire project site drains out to one point of connection and thus was modeled as one basin. The natural conditions of the site were input into the SOCHM software as open brush very steep and all impervious. The proposed condition was broken into pervious land use, urban very steep for the perimeter slopes and urban flat for the internal landscape areas. The proposed impervious includes the buildings, flatwork, streets, etc and is flat.

From there, a vault was modeled through an iterative process was used to determine the necessary detention volume to required to reduce stormwater flows to the natural condition. Compliance is defined as not exceeding the natural runoff flow rates and durations by more than 10% of the time, for flow rates from 10% of the 2 year flowrate up to the 10 year flow rate. The flows will be detained in an underground vault and released through an orifice opening which was also sized through the SOCHM model. The vault will be approximately 28’x130’x5’ deep. Full SOCHM model results can be found in Attachment F.
1227
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo
SHEA HOMES Section 7

Page 25 ends

Section 7 Educational Materials Index
Educational Materials
Residential Material
(http://www.ocwatersheds.com)
Check If
Applicable
Business Material
(http://www.ocwatersheds.com)
Check If
Applicable
The Ocean Begins at Your Front Door Tips for the Automotive Industry Tips for Car Wash Fund-raisers Tips for Using Concrete and Mortar Tips for the Home Mechanic Tips for the Food Service Industry Homeowners Guide for Sustainable
Water Use
Proper Maintenance Practices for Your
Business
Household Tips
Compliance BMPs for Mobile
Businesses
Proper Disposal of Household
Hazardous Waste
Other Material
Check If
Recycle at Your Local Used Oil Attached
Collection Center (North County)
Recycle at Your Local Used Oil
Collection Center (Central County)
Recycle at Your Local Used Oil
Collection Center (South County)
Tips for Maintaining a Septic Tank
System
Responsible Pest Control
Sewer Spill
Tips for the Home Improvement Projects
Tips for Horse Care
Tips for Landscaping and Gardening
Tips for Pet Care
Tips for Projects Using Paint
D I
~ □
□ □
□ □
~ □
~ □
~
□
□ □
~ □
□ □
~ □
□ □
~ □
~ □
~ □
~ □
~ □
1228
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Appendix

Attachment A: WQMP Site Plan
1229
P3 P3 P3 P2 P2 P1 P3 P2 P1 P2 P1 P3 P2 P2 P1 P1 P3 P3 P2 P2 P1 P3 P2 P2 P1 P3 P2 P2 P1 P3 P2 P2 P1 P3 P3 P3 P2 P2 P1
P3 P2 P2 P1 P1 P1 P2 P2 P2 P2 P3 P4 P4 P4 P4 P5 P5 P5 P5 SD SD SD SD SD

SD SD SD SD SD SD SD SD SD SD SD
SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD PREPARED FOR: PREPARED BY: WQMP EXHIBIT LEGEND =•t 390.4 390.5 390.3. 8 +390.6 388.6 >- 386.5 w z 0::: =i 0 385.7 + 384.3 I I ,~ I I I I ' ,. 1. I' f I I I I I 392.5 I!] 392t -- -P 391.6 + 391.6 )- ·' ;;:=~~~ ...... \ + 391.6 =:',;:I t 391.5 CONC 391.4 391.:'.f- \A/A 391.7 \ \ w Q_ <( u Cf) \ \ 0 z <( _J \ w \ g, \ \ \ \ \ \ ' - --=----------- l-'---r-Hb"2 ld ld 1----+'I A A LJLJ LJLJ 1717 1717 1717 1717 17 17 111------'-'I VV VV VV VV V V l-'--,,-ffb"2 1717 V V I Ql~ CJ 1717 1717 1717 17 1717 V V I w Q_ <( u Cf) 0 z <( _J w Q_ 0 _J Cf) -- 11--------4-"' V V V V V V V SLOPE LANDSCAPE !-'--,,-ff b "2 , -~--~-- 1 --~ j LJALJA l-'---r-lb"2 t'l;;;jj:::1aa-~~1--1~ rd~ A A A: '; A !1!A~~ d=k-~ ~ -_d:_dc_~ ~ -~ J_:_b_4:_JJ_ ~ _~~-~ ~-=-i-~~-=-~-~~ _ _:: __ j. }=bALJ~LJ~LJ~LJ~LJ~LJ~LJ~LJ~ I I ! 7lE::~~~~ ::EiI:~~ I~ 11----------0! 17 17 17 17 17 17 17 j VV VV VV V I I j l~~-t-;.t I j ~-~ -!:~ d A A I j I I j I LJLJ LJ 1717 1717 1717 1717 1717 vv vv vv vv vv E9 1717 1717 1717 1717 1717 V V V V V V V V V V 63 60 60 6J 11-------"1 17 17 17 17 1717 17 17 17 j VV VV VV VV V 1717 1717 1717 1717 1717 V V V V V V V V V V 1717 1717 1717 1717 V V V V V V V V I I j_ 1-,---1-1 I I j ~-- E9 E9 38~ 5 lr"t'1rnii~ffitimt~~~===t:=~~~~~3;;;;"'-~~~~~ir~- --:~~~~~~~~ 1~:1~=re, "'" ~·- '·1,~ -360.-3 -36-0.2 A-SPIJ ~------~.~,R----- 59.8 + 359.5 A A A2 LJLJ 0.2 355 1717 1717 V V V V • ,J IC :, ) 1 J ) 1717 17 1717 1717 1717 V V V V V V V V V c9 A AA AA AA LJ LJLJ LJLJ LJLJ 63 60 60 6J A A A A A A A A A A LJLJ LJLJ LJLJ LJLJ LJLJ 1717 1717 1717 17 J 0.. l. V V V V V V V V ASPI PIPE- 0 PROPOSED MODULAR WETLAND SYSTEM == PROPOSED STORM DRAIN SYSTEM PROPOSED CATCH BASIN WITH STENCILING - LANDSCAPED AREAS (EFFICIENT IRRIGATION, IMPERVIOUS AREA DISPERSION, STREET TREES) CONC - SLOPES (HILLSIDE LANDSCAPING, PROTECT SLOPES) 345.5 344.6 :!,A-'=> + - HYDROMOD DETENTION i i 16 0 344.4 3~5 \ 345.3 \ CONC 343.4 t ANK E9 ~---LJ - - 63 60 6J A A A A A A A A A A LJLJ LJLJ LJLJ LJLJ LJLJ --:-93 17 1717 1717 1717 1717 1717 V V V V V V V V V V V V E9 0 " I I I I I I ! I i I ! \ \ 0 " I I I ! I I 341. C: = C: = c:= c:= c:= ---- c:= c:= c:= c:= c:= c:= - I I 337.5 338., 33! 3. 341.6 [ .----------------~----------------,------------------r---------1-"' SHEA Hat.ES 2 ADA, SUITE 200 IRVINE, CA 92618 (949) 526-8800

PROACTIVE

ENGINEERING & SURVEYING
27051 Towne Ce ntre Drive, Suite 270
Foothill Rancti, CA 92610 949,716.7460
27181 ALISO CREEK RD
<O
!?. PLAN PREPARATION: "
JAI\UARY 2026 C
0 ,
SHEET _1 OF _1 i a:
------------------------------------------------------------------------------------------------------------------- ....
1230
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Appendix

Attachment B: BMP Calculations
1231
Worksheet 9: Flow-Based Compact Biofiltration with Supplemental Retention Method ALL A1 A2 B1 B2 C1 C2 D1 D2 E F G H I J
1 Enter the time of concentration, Tc (min) (See E.2.3) Tc= min 9.3 7 6 7.7 7.6 7.6 5.5 9 5.5 8.6 8 8.5 7 6.5 7.62 Using Figure E-7, determine the design intensity at which the estimated time of concentration (Tc) achieves 80% capture efficiency, I 1 I1= in/hr

0.23 0.24 0.25 0.24 0.24 0.24 0.25 0.23 0.25 0.23 0.24 0.23 0.24 0.25 0.24 3 Enter capture efficiency corresponding to the upstream HSCs and/or upstream BMPs, Y2 Y
2 = inches 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
4 Using Figure E-7, determine the design intensity at which the time of concentration (Tc) achieves the upstream capture efficiency(Y2), I 2 I2= % 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
5 Determine the design intensity that must be provided by BMP, I design= I 1 -I 2 Idesign_80%= in/hr

0.23 0.24 0.25 0.24 0.24 0.24 0.25 0.23 0.25 0.23 0.24 0.23 0.24 0.25 0.24 6a Enter DMA area tributary to BMP (s), A (acres) A= acres 7.92 0.49 0.25 0.44 0.38 0.83 0.12 0.35 0.05 0.51 0.95 0.93 0.29 0.42 0.766b Enter DMA Imperviousness, imp (unitless) imp= 0.66 0.37 0.17 0.35 0.28 0.66 0.08 0.26 0.04 0.34 0.73 0.76 0.24 0.31 0.66 6c Calculate runoff coefficient, C= (0.75 x imp) + 0.15 c= 0.65 0.43 0.28 0.41 0.36 0.65 0.21 0.35 0.18 0.41 0.70 0.72 0.33 0.38 0.656d Calculate flowrate to achieve 80 percent capture, Q 80% = (c x I design x A)
Q80%
= cfs 1.17 0.05 0.02 0.04 0.03 0.13 0.01 0.03 0.00 0.05 0.16 0.15 0.02 0.04 0.12 7 Calculate design flowrate,
Q design= Q 80% x 150% Qdesign
= cfs 1.76 0.08 0.03 0.07 0.05 0.19 0.01 0.04 0.00 0.07 0.24 0.23 0.03 0.06 0.18 4x8 4x4 4x8 4x4 8x8 4x4 4x4 4x4 4x6 8x12 8x8 4x4 4x6 8x8 Step 1: Determine the design capture storm depth used for calculating volumeStep 2: Calculate the design flowrateSupporting Calculations MWS Unit
Describe system:Proprietary biofiltration units will be used to meet the required treatment design flowrate.Provide time of concentration assumptions:Used the nomograph in the TGD 1232
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Appendix

Attachment C: Educational Materials
Will be provided with FWQMP
1233
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Appendix

Attachment D: Operations and Maintenance
Plan
Will be provided with FWQMP
1234
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Appendix

Attachment E: Geotechnical Report
1235
17991 Fitch • Irvine, California 92614 • PHONE (949) 442-2442 • FAX (949) 476-8322 • www.nmggeotechnical.com November 25, 2025
Project No. 24074-02
To: Shea Homes
15261 Laguna Canyon Road, Suite 100
Irvine, California 92618
Attention: Ms. Danielle Prigmore
Subject: Preliminary Geotechnical Investigation and Review of Vesting Tentative Tract Map 19442, Proposed Residential Redevelopment, Aliso Viejo, California

EXECUTIVE SUMMARY
In accordance with your request and authorization, NMG Geotechnical, Inc. (NMG) has reviewed the Vesting Tentative Tract Map (VTTM) 19442 and Engineering Site Plan and performed a preliminary geotechnical investigation for the proposed redevelopment at the subject site. Our study focused on evaluating the existing geotechnical conditions with respect to the proposed residential development. The project will consist of the demolition of the existing office park, regrading of the site, and construction of 137 new residential homes. The project will require minor modification of the existing perimeter slopes and includes addition of retaining walls at the top of existing slopes up to 6 feet tall along the eastern and southeastern perimeter and retaining walls at the toe of slopes up to 8 feet tall along the western and northern perimeter. The project construction will also include new utility and interior street infrastructure. The VTTM reviewed for this report was prepared by Proactive Engineering Consultants (Proactive).

This geotechnical study included a review of background reports and maps, review of a prior geotechnical investigation report covering the subject site and surrounding area prepared by Jack G. Raub Company (1987), field reconnaissance, drilling of six hollow-stem-auger borings, excavation of four geotechnical test pits, laboratory testing, preliminary geotechnical analysis of the collected data, and preparation of this report.

The site is predominantly underlain by a thin mantle of compacted fill over sedimentary bedrock consisting of interbedded sandstone, siltstone and diatomaceous siltstone. Quaternary-age alluvial deposits were encountered in the southeast corner of the property, at depths of approximately 40 feet. The compacted fill thickness varies from about 2.5 to 5 feet over the majority of the site, with the thickest fills (20 to 40 feet thick) located in the southern portion of the site.

No active or potentially active faults are mapped beneath the property. The nearest known seismogenic source is the San Joaquin Hills blind thrust fault, located approximately 2.5 miles to the northeast. Furthermore, the site is not located within a mapped seismic hazard zone for ~ ~~~hnical, Inc.
1236
24074-02
November 25, 2025
251125 NMG VTTM Rpt ii
NMG
liquefaction or earthquake-induced landsliding (CDMG, 2001). The seismic design parameters were prepared in accordance with the 2025 California Building Code.

The main geotechnical issues impacting the project development include:
• Removal of the existing fill and weathered bedrock in the upper 5 feet to provide a uniform cap of certified engineered fill for the building pads. The demolition of existing structures and utilities may require deeper excavations and would result in additional loose, disturbed soil that will need to be removed and replaced as compacted fill. • The finer grade bedrock (siltstone and claystone) is more plastic, expansive, corrosive, and generally poorer subgrade material than the existing fill and coarse-grained bedrock.

Additional mixing and blending of fill materials may be needed to reduce the impact on the project design (i.e. building foundations). Additionally, deepened removals may be required where finer grained bedrock is exposed to mitigate differential expansion. • Retaining wall backcuts into the existing ascending slopes should be mapped to document the existing bedrock conditions and determine the extent of the compacted fill cover for the slope. • Deeper utility excavations into the bedrock may encounter siltstone and claystone layers with adverse bedding conditions which may adversely impact trench stability. This condition should be closely monitored during construction. Excess spoils from the siltstone bedrock should not be placed near the edge of the trench, especially on the up-dip side of the bedding. • Potential for strong seismic shaking during an earthquake on a regionally active fault. • Addition of design fill and retaining wall at the top of slope along the eastern perimeter may cause surcharge loading to the existing retaining wall for the gas station. This condition will require further evaluation once retaining wall plans are made available. • The varying deep and shallow bedrock conditions will influence the seismic and foundation design and will also need to be taken into account during the site grading/earthwork operations and underground utility construction.
• Due to the presence of shallow bedrock, the site is considered unsuitable for stormwater infiltration.

This report presents our geotechnical findings, conclusions and preliminary recommendations for project planning and preliminary design related to the tentative tract plan. The report includes a Geotechnical Map (Plate 1) which depicts the boring and test pit locations by NMG, and the subsurface geologic conditions based on prior mapping by others. Cross section A-A’ (Figure 4) depicts the existing and design conditions and was used for our preliminary slope stability analysis where a portion of the slope below the fire station exposed bedrock, and in a second location along the eastern perimeter where design fill is proposed above an existing slope with a retaining wall at the toe of slope. The geotechnical boring and trench logs and laboratory test data from our subsurface exploration are included in Appendices B and C, respectively. Appendix D includes 1237
24074-02
November 25, 2025
251125 NMG VTTM Rpt iii
NMG
the code-based seismic analysis. The results of our slope stability analysis are presented in Appendix E. Appendix F includes NMG's general earthwork and grading specifications.

The proposed residential redevelopment at the site is considered geotechnically acceptable, providing the recommendations provided in this report and future reports are incorporated into the design, grading and construction. The recommendations in this report are preliminary and final geotechnical recommendations will be provided based on review of the future grading, foundation, and improvement plans. Additional testing of the subgrade and foundation soils will need to be performed after completion of the site grading for confirmation of the recommendations.

NMG's expertise and scope of services did not include assessment of potential subsurface environmental contaminants or environmental health hazards.

If you have any questions regarding this report, please contact us. We appreciate the opportunity to provide our services.

Respectfully submitted,
NMG GEOTECHNICAL, INC.

William Goodman, CEG 1577 Karlos Markouizos, RCE 50312
Principal Geologist Principal Engineer
WG/KGM/je
Email Distribution: Addressee
Ms. Emilie Simard, Shea Homes
Mr. Peter Carlson, Carlson Strategic Land Solutions
1238
24074-02
November 25, 2025
251125 NMG VTTM Rpt iv
NMG

TABLE OF CONTENTS

1.0 INTRODUCTION ...............................................................................................................1

1.1 Scope of Work .....................................................................................................................1

1.2 Site Location and Existing Conditions ................................................................................1

1.3 Site Reconnaissance .............................................................................................................2

1.4 Site History ..........................................................................................................................2

1.5 Prior Geotechnical Work .....................................................................................................3

1.6 Proposed Development ........................................................................................................3

1.7 Subsurface Exploration ........................................................................................................3

1.8 Infiltration Potential .............................................................................................................4

1.9 Laboratory Testing ...............................................................................................................4

2.0 GEOLOGIC CONDITIONS ................................................................................................5

2.1 Geologic Units .....................................................................................................................5

2.2 Geologic Structure/Faulting .................................................................................................5

2.3 Seismic Hazards ...................................................................................................................6

2.4 Groundwater ........................................................................................................................6

2.5 Engineering Soil Properties .................................................................................................7

2.6 Liquefaction Potential ..........................................................................................................7

2.7 Settlement Potential .............................................................................................................8

2.8 Slope Stability ......................................................................................................................8

2.9 Existing Asphalt Pavement ..................................................................................................8

2.10 Corrosivity Testing ..............................................................................................................8

2.11 Earthwork Factors ................................................................................................................9

3.0 CONCLUSION AND PRELIMINARY RECOMMENDATIONS ..................................10

3.1 General Conclusion ............................................................................................................10

3.2 Demolition of Existing Structures .....................................................................................10

3.3 Site Preparation and Earthwork .........................................................................................10

3.4 Infiltration ..........................................................................................................................11

3.5 Settlement Potential ...........................................................................................................11

3.6 Foundation and Slab Design Guidelines ............................................................................11

3.7 Foundation Setbacks ..........................................................................................................12

3.8 Seismic Design Guidelines ................................................................................................12

3.9 Pavement Design ...............................................................................................................13

3.10 Exterior Concrete ...............................................................................................................14

3.11 Soil Corrosivity and Cement Type .....................................................................................14

3.12 Pipelines, Trench Excavations, Temporary Shoring, and Backfill ....................................14

4.0 PLANNING AND DESIGN RECOMMENDATIONS ....................................................16

5.0 LIMITATIONS ..................................................................................................................17 1239
24074-02
November 25, 2025
251125 NMG VTTM Rpt v
NMG
TABLE OF CONTENTS (Cont'd)
Figures & Illustrations
Figure 1 – Site Location Map – Rear of Text
Figure 2 – Seismic Hazards Map – Rear of text
Figure 3 – Regional Fault Map – Rear of Text
Figure 4 – Cross Section A-A' – Rear of Text
Plate 1– Geotechnical Map – Rear of Text
Appendices
Appendix A – References
Appendix B – Geotechnical Boring and Test Pit Logs
Appendix C – Summary of Laboratory Test Results
Appendix D – Seismic Parameters
Appendix E – Slope Stability Analysis
Appendix F – General Earthwork and Grading Specifications 1240
24074-02
November 25, 2025
251125 NMG VTTM Rpt 1
NMG

1.0 INTRODUCTION

1.1 Scope of Work
The purpose of our geotechnical study was to evaluate the existing subsurface conditions in light of the proposed residential redevelopment at the subject site. Our investigation and this report are based upon our review of the Vesting Tentative Tract Map and Engineering Site Plan prepared by Proactive Engineering (received November 14, 2025).

Our scope of work included the following:
• Background review of available published and unpublished reports and maps (Appendix A). • Review of available historic aerial photographs and topographic maps pertinent to the site and surrounding area.
• Drilling, logging, sampling, and backfilling of six hollow-stem-auger borings (H-1 to H-6) to approximate depths ranging from 11 to 51 feet deep below ground surface (bgs). Approximate boring locations are shown on Plate 1, and the boring logs are included in Appendix B. • Excavation of four geotechnical test pits to confirm the geologic and as-graded conditions of a portion of the perimeter slope below the fire station. Approximate test pit locations are shown on Plate 1, and the logs are included in Appendix B.
• Laboratory testing of relatively undisturbed ring and bulk soil samples. Test results are summarized in Appendix C. Soil test results from the prior investigation in the area were also utilized in our engineering assessment of the soil properties. • Geotechnical evaluation and analysis of the compiled data with respect to the proposed residential development. This included seismic design analysis (Appendix D) and preliminary slope stability analysis (Appendix E).
• Preparation of this report including our findings, conclusions, recommendations, and accompanying illustrations. The report includes a Geotechnical Map (Plate 1) and geologic Cross-Section A-A' (Figure 4).

1.2 Site Location and Existing Conditions
The subject site is located in the city of Aliso Viejo, Orange County, California, south of Pacific Park Drive, west of Aliso Creek Road and bounded to the northwest by an existing fire station and Journey street, northeast by an existing gas station and south by an existing office complex (Figure 1).

The roughly 8.4-acre site consists of generally flat ground with elevations ranging between 346 mean sea level (msl) at the southeast corner to 388 msl in the northwest corner. This measurement includes slope areas within the property. The relief across the site for the building area is about 8 feet. A 25- to 35-foot ascending, vegetated slope is present on the west to northwest area of the site with a descending slope on the eastern area bordering Aliso Creek Road that is up to 16 feet tall. Along the northeast perimeter of the site, adjacent to the gas station, there is a combination of 1241
24074-02
November 25, 2025
251125 NMG VTTM Rpt 2
NMG
descending slopes and retaining walls up to approximately 6 feet tall. These slopes are generally constructed at 2H:1V slope ratios. The majority of the site is developed as paved parking lots with three, two-story office buildings, with the exception of the ascending and descending slopes.

1.3 Site Reconnaissance
Our site reconnaissance was initially performed on November 26, 2024 and more recently on October 13, 2025. The site was accessed from Aliso Creek Road and the primary field observations are listed below:
• Three large two-story office buildings are present on the site. The majority of the site is covered in asphalt pavement and hardscape.
• An approximately 2:1 (H:V) descending slope up to 16 feet tall is present from the at-grade building and parking lot area down to Aliso Creek Road and a southern access street. The slopes are covered in vegetation and large trees.
• At the southeastern corner of the subject site, there is an existing 5-foot retaining wall that is tilting 13 degrees to the southeast.
• A retaining wall up to approximately 6 feet high is present on the northeastern boundary associated with the Shell gas station car wash facility. • An ascending 2H:1V slope up to approximately 35 feet high is present on the northwestern and western boundary of the site. The slopes have one concrete stormwater v-ditch and are covered with vegetation and large trees. Bedding was observed dipping into slope at the surface in the northern portion of this slope. As the slope extends to the west, bedding was no longer visible at the surface and a subdrain outlet was observed at the slope face. • Minor cracking was observed in the asphalt pavement across the site. Some cracking and separations were observed in the curbs and hardscape and were generally associated with root systems from nearby trees.

1.4 Site History
The following site history is based on available historic aerial photographs dating back to 1938. • In 1938, the subject property was vacant natural hillside area with two canyons draining southward. This status continued until 1987-1988.
• In 1987, dirt roads are observed crossing the site with associated local drill pads. • In 1988, mass grading at the site was in progress and both small canyons were being filled in. • Between 1988 and 1991, the site became a finished mass graded pad, with a fire station constructed on the northwest border bounded by an ascending 25- to 35-foot-high slope, an office complex constructed on the southern border, a surface drainage detention basin at the 1242
24074-02
November 25, 2025
251125 NMG VTTM Rpt 3
NMG
northeast corner, and both Pacific Park Drive, and Aliso Creek Road being constructed on the north and east borders.
• Between 1996 and 1997, the gas station was constructed on the northeast border of the site.

The gas station was constructed approximately 10 feet below the elevations at the subject site, with a descending slope from the subject site.
• Construction of the office buildings began between 1998 and 1999 and was completed by 2000. • Between 2011 and 2012, the eastern descending slope to the existing gas station was cut back, and an approximately 6-foot-high retaining wall was constructed for the addition of a driveway and carwash.
• The site has remained essentially unchanged since 2012.

1.5 Prior Geotechnical Work
The original geotechnical investigation that included this site was performed by the Jack G. Raub Company in 1987 (Appendix A). They provided the results of their subsurface exploration and geologic field mapping and provided recommendations for mass grading.

Based on our review of city files, the report of mass grading that occurred between 1988 and 1991 and the reports related to design, grading and construction for the existing commercial development were not available for review.

1.6 Proposed Development
According to the architectural site plan, prepared by Woodley Architectural Group, Inc., received November 17, 2025, and the tentative tract map prepared by Proactive Engineering received November 14, 2025, the proposed residential development consists of 3-story attached residential units, open space landscape areas, and an interior street network with parking stalls for guest parking. The total unit count for the development is 137 units with approximately 70 units consisting of a 3-story townhome row style product and the remaining 67 units consisting of a 3-story garden-court-style product. Retaining walls up to 8 feet high are planned at the toe of slopes descending from the fire station and from Journey Street along the west side of the project site, and at the top of slopes descending to the gas station and Aliso Creek Road along the northeastern perimeter. Primary access to the site will be from Pacific Park at the north end of the development and a secondary access from Aliso Creek Road at the southeast corner.

The preliminary cut-fill map prepared by Proactive, shows design grading to consist of 4,200 cubic yards (CY) of cut and 9,800 CY of fill, for a net import of 5,600 CY. We do not anticipate site grades to change significantly.

1.7 Subsurface Exploration
Our initial subsurface exploration was performed on December 6, 2024, and included excavation of six hollow-stem-auger borings (H-1 through H-6) to depths ranging from 11 to 51 feet below 1243
24074-02
November 25, 2025
251125 NMG VTTM Rpt 4
NMG
ground surface (bgs). The hollow-stem borings were initially excavated with a hand-auger to 5 feet deep to confirm no conflicts with shallow utilities and then sampled and geotechnically surface-logged by a geologist to evaluate soil stratigraphy and groundwater conditions. Soil samples were taken at selected intervals with a 2.5-inch-inside-diameter California split-barrel sampler and were also used to obtain a measure of resistance of the soil to penetration (recorded as blows-per-foot on our geotechnical boring logs). Drive weights were with a 140-pound automatic hammer for all borings. Bulk samples of onsite soils were collected from the cuttings and used for additional soil identification purposes and laboratory testing. Soil samples were visually classified in accordance with the Unified Soil Classification System (USCS). The depths of the pavement sections were recorded with each boring and are presented on the logs in Appendix B. The approximate locations of the borings are shown on the Geotechnical Map (Plate 1).

Recently, NMG excavated four geotechnical test pits (T-1 through T-4) with a backhoe at the toe of the slope ascending to the fire station at the northwest corner of the site. The purpose of these excavations was to evaluate the limits of compacted fill and bedrock conditions exposed in the lower portion of the slope. The approximate location of the test pits is depicted on the geotechnical map (Plate 1), and the logs are provided in Appendix B.

1.8 Infiltration Potential
Percolation testing was not performed during subsurface exploration since the site consists of compacted fill over siltstone and sandstone bedrock. This condition is not suitable for infiltration.

1.9 Laboratory Testing
The laboratory testing performed is listed below. The test results provide soil engineering properties for the selected samples of the onsite soils. Existing laboratory test results from prior geotechnical studies in the area were also reviewed and utilized for this study. • In-situ density and moisture content.
• Soluble sulfate
• Expansion index
• Atterberg limits
• Hydrometer
• Sieve analysis
• Maximum density
• Consolidation
• Direct shear
• Corrosion testing
• R-Value
Laboratory test results are included in Appendix C. In-situ density and moisture contents are presented on our boring logs in Appendix B.
1244
24074-02
November 25, 2025
251125 NMG VTTM Rpt 5
NMG

2.0 GEOLOGIC CONDITIONS
The site is located within the San Joaquin Hills of the western Peninsular Ranges geomorphic province. This province is characterized by Cretaceous-age granitic bedrock and Mesozoic-age metamorphic rock overlain by various terrestrial and marine deposits. Structurally, the San Joaquin Hills are bounded by the Newport-Inglewood-Rose Canyon Fault Zone to the west and the Elsinore Fault Zone to the east.

According to mapping by (Morton and Miller, 2006; Raub Company, 1987), the primary geologic unit at the subject site is Miocene age deposits of the Monterey and Capistrano Formations.

2.1 Geologic Units
Based on available geologic maps (Morton and Miller, 2006; Raub Company, 1987), NMG site reconnaissance, and NMG hollow-stem borings (Appendix B), the site is covered by artificial fill and underlain by Miocene Monterey/Capistrano Formations. The northwestern ascending slope bordering Pacific Park Drive exposes diatomaceous siltstone bedrock of the Monterey Formation.

Based on NMG hollow-stem borings, the artificial fill generally consists of light olive brown, grayish brown and light yellowish-brown silty/clayey sand and sand that is fine to coarse grained, medium dense to dense, and generally ranges in moisture content from 14.2 to 18.1 percent in the upper 6 feet. Locally, moisture was found to be as high as 34.6 percent. The underlying Miocene Monterey Formation generally consists of light grey to very dark grey diatomaceous siltstones and claystones that are moist to wet, hard and have trace fish scales. Locally, we observed light olive brown to pale yellow silty fine sandstones that were moist, dense/very dense and friable in the Monterey formation. The underlying Tertiary Capistrano Formation, Oso Member generally consists of light gray to pale olive clean fine sandstone that is moist, dense/very dense, micaceous and friable. Quaternary-aged alluvium was encountered in the southeast corner of the site in boring H-2, between 40 and 50 feet deep below the existing ground surface. The alluvium consists of olive gray clayey fine to medium sand that was damp to moist and very dense.

During our limited subsurface exploration, significant cementation was not encountered in the Capistrano or Monterrey Formations. However, it is not uncommon to encounter cemented beds within these formations. Thin cemented beds may be encountered locally in deeper excavations that may cause difficult ripping.

2.2 Geologic Structure/Faulting
Based on published mapping by the State of California (CGS, 2010), there are no active faults that transect the site, and the site is not located within an Alquist-Priolo Earthquake Zone of Required Investigation (CGS, 2018). Also, no evidence of active faulting was observed during the prior investigation by the Jack G. Raub Company (1987). The closest major active faults identified by the state are the San Joaquin Hills Thrust Fault located approximately 2.5 miles to the northeast and the Newport Inglewood-Rose Canyon Fault zone (Dana Point Section) located approximately

6.1 miles to the southwest and the Glen Ivy section of the Elsinore Fault Zone located 19.2 miles to the northeast.
1245
24074-02
November 25, 2025
251125 NMG VTTM Rpt 6
NMG
Based on the California Geological Survey, there are no active faults in or near the subject site.

2.3 Seismic Hazards
Using the USGS computer program (USGS, 2025) and the site coordinates of 33.5695 degrees north latitude and 117.7247 degrees west longitude, the controlling fault at the site is the San Joaquin Hills Fault located 4.1 kilometers (2.5 miles) northeast of the site. The maximum Moment Magnitude for the Controlling Fault is 7.27 MW. The other faults noted that can produce strong ground shaking at the site include the Newport-Inglewood (Offshore), and Elsinore (Glen Ivy section) Faults. Based on review of published maps, historic aerial photographs and topographic maps, the potential for primary ground rupture due to an earthquake is considered very low.

Seismicity: Properties in southern California are subject to seismic hazards of varying degrees depending upon the proximity, degree of activity, and capability of nearby faults. These hazards can be primary (i.e., directly related to the energy release of an earthquake, such as surface rupture and ground shaking) or secondary (i.e., related to the effect of earthquake energy on the physical world, which can cause phenomena such as liquefaction and ground lurching). The site is not located in a seismic hazard zone for liquefaction potential (CDMG, 2001), as shown in Figure 2.

Liquefaction potential is discussed further in Section 2.5. Secondary seismic hazards, such as tsunami and seiche, need not be considered since the site is located approximately 4 miles from the ocean or any confined bodies of water and at elevations well above mean sea level.

As with the majority of sites in Southern California, the primary seismic hazard for this site is ground shaking due to a future earthquake on one of the major regional active faults, such as the San Joaquin Hills Blind Thrust, Newport-Inglewood, or the Elsinore-Glen Ivy Faults. We anticipate the site will be designated as Class CD. However, due to the lack of seismic data at depth, we are unable to determine the Vs (30) shear wave velocity at this time and the default category has been used to develop the preliminary seismic design parameters. The seismic design parameters are presented in the Conclusions and Recommendations section of this report. Seismic design parameters were calculated based on a computer program by the Structural Engineers Association/Office of Statewide Health Planning and Development (2025). The results are tabulated in Section 3.5 and the data is included in Appendix D.

2.4 Groundwater
Groundwater was not encountered by NMG during our subsurface exploration to a depth of 51.5 feet. Also, based on information on the GeoTracker website there were several borings excavated at the 76-gas station in 2009 that were drilled from 40 to 51 feet deep and did not encounter groundwater. This gas station is located approximately 800 feet north of the subject site.

Therefore, based on our subsurface investigation and publicly available well data groundwater is expected to be greater than 51.5 feet deep.
1246
24074-02
November 25, 2025
251125 NMG VTTM Rpt 7
NMG

2.5 Engineering Soil Properties
Based on the borings at the site, the moisture content of the existing fill generally ranges from 14.2 to 18.1 percent and in-place dry density ranged from approximately 85.4 to 124.8 pcf. Locally, moisture was found to be as high as 34.6 percent. The near-surface fill material (upper 5 feet) is generally moist. The grain size testing indicates 30 to 59 percent fines content (passing No 200 sieve). Most of the soils are non-plastic however, some soils are clayey and had Liquid Limits of 28 to 41 percent and Plasticity Index of 9 to 16 percent. Maximum density testing was performed on one bulk samples collected from the upper 5 to 10 feet that consisted of clayey sand (USCS classification of SC). The maximum dry density test result was 114 pcf with optimum moisture content of 15.5 percent.

Based on the USCS classification, the existing fill consists of crudely layered SP, SC, CL, SM, and ML soils. The soil sample descriptions, classification (USCS group symbol), in-situ soil dry density and moisture content are presented on the boring logs (Appendix B).

Direct shear testing was performed on one sample remolded to 90 percent (based on ASTM Test Method D1557) to evaluate the strength of reworked onsite soils, to assess the strength of the future fill material. The selected sample was a clayey sand material sampled in the upper 5 feet. The test result indicated peak cohesion of 375 psf and a soil friction angle of 27 degrees, and ultimate cohesion of 180 psf and a soil friction angle of 26 degrees. The original direct shear testing of the bedrock in the area indicated friction angles of 27 to 47 degrees and cohesion of 80 to 625 psf.

Expansion index tests were performed on selected bulk samples from the existing fill to evaluate the expansion potential of onsite soils. Based on the laboratory test results, the expansion index (EI) varies from 9 to 23 which corresponds to "Very Low" to "Low" expansion potential. However, due to the presence of the Monterrey Formation bedrock in the shallow subsurface, higher expansive soils should be expected during demolition and grading.

R-value testing was performed on a sample of the clayey sand fill and indicated a minimum value of 29 (by expansion).

The direct shear, Atterberg Limit, and maximum density/optimum moisture content test results for the bedrock materials in the area included in the investigation report (JGR, 1987) were also reviewed and utilized.

2.6 Liquefaction Potential
The subject site is not located within a zone of liquefaction potential as mapped by the State (Figure 2). According to mapping by CDMG (2201) Historic high groundwater at the site is 20 feet below ground surface (bgs). However, groundwater was not encountered while drilling during prior investigations by others or during the current investigation to depths up to 51.5 feet bgs.

Liquefaction potential at the subject site is considered very low to nil due to the significant depth to groundwater and relatively shallow bedrock across the majority of the site. 1247
24074-02
November 25, 2025
251125 NMG VTTM Rpt 8
NMG

2.7 Settlement Potential
We anticipate the future compacted fill and underlying bedrock will have low compressibility.

Based on the minor design grading and the light structural loads, we anticipate only minor settlement. The potential settlement due to seismic shaking should also be minor.

2.8 Slope Stability
The slopes around the perimeter of the site consist mainly of fill slopes or stabilization fill slopes with a limited window of exposed bedrock below the fire station. The bedrock bedding is generally favorable with respect to slope stability. The existing slopes are 2H:1V and up to 35 feet in height.

Slope stability was performed utilizing Cross-Section A-A’ (Figure 4) for the western perimeter ascending slope and the eastern descending slope. The western slope will have a proposed retaining wall cut into the toe of slope. This wall will have a maximum height of 8 feet. A temporary cut slope will be required for construction of the proposed retaining wall at toe of slope. The existing descending eastern slope has an existing retaining wall at the bottom next to the car wash. The height of the slope and retaining wall combination is 9 feet. To accommodate the design finish grades for the new development a retaining wall up to 6 feet in high is proposed at the top of slope.

The results of the preliminary slope stability indicate the revised slope with the new retaining walls have a global factor of safety greater than 1.5. The factor of safety for the pseudostatic slope stability analysis has a factor of safety greater than 1.1. The temporary slope for the new retaining wall construction is anticipated to expose competent bedrock. The results of the slope stability analysis is presented in Appendix E.

2.9 Existing Asphalt Pavement
The existing asphalt encountered during our subsurface exploration within the parking lot area varied from 3 to 4.5 inches of asphalt concrete (AC) over 5 to 9 inches of aggregate base (AB).

The actual pavement section measurements were obtained during our subsurface exploration and are provided on the boring logs (Appendix B).

2.10 Corrosivity Testing
Corrosion testing was performed by Keegan Labs on three samples provided by NMG to evaluate Resistivity, pH, Sulfate content, and Chloride content. One of the soil samples was of the fine grained (silty) bedrock and the other two samples were of the existing fill (clayey sand/sandy clay).

As a result of the varied soil types, the corrosion potential ranged from corrosive to severely corrosive to metals, negligible to severely corrosive to concrete, and low to moderate chloride exposure. Soil pH values indicate slight to medium alkalinity. The soil analysis lab test results are presented in Appendix C and summarized below.
1248
24074-02
November 25, 2025
251125 NMG VTTM Rpt 9
NMG
Soil Corrosion Test Test Results
Minimum Resistivity (ohm-cm) 322 -1660
pH 7.0-7.7
Sulfate Content (ppm) 96 – 5,220
Chloride Content (ppm) 44 – 1,061

2.11 Earthwork Factors
The loss or gain of volume (shrinkage or bulking, respectively) of excavated natural materials and re-compaction as fill varies according to earth material type and location. This volume change is represented as a percentage shrinkage (volume loss) and as a percentage bulking (volume gain) after re-compaction of a unit volume of cut in this same material in its natural state. We anticipate the existing fill materials and near-surface bedrock will vary from 2 percent bulk (bedrock) to 1 percent shrinkage (existing fill). The loss of volume due to demolition is not included in our earthwork factors. Due to prior site use, subsidence at the site is anticipated to be negligible. 1249
24074-02
November 25, 2025
251125 NMG VTTM Rpt 10
NMG

3.0 CONCLUSION AND PRELIMINARY RECOMMENDATIONS

3.1 General Conclusion
Based on review of the VTTM and Engineering Site Plan, the proposed residential redevelopment at the site is considered geotechnically feasible. This report provides the collected site-specific subsurface information and preliminary recommendations that can be used for planning and initial design at the site. Specific geotechnical recommendations for design, grading, and construction will be provided in future reports based on review of the design plans for the project.

Our subsurface investigation confirmed that most of the site has between 2.5 and 5 feet of fill over bedrock. The southeastern and southwestern perimeter of the site have thicker compacted fills and alluvium where canyons were filled during prior grading. The variable as-graded and geologic subsurface conditions will influence the seismic design parameters, foundation design, grading and earthwork, and underground utility construction. The recommended remedial grading and deeper utility excavations will encounter bedrock across the majority of the site. Where bedrock is encountered, grading may require extra mixing and blending locally to produce a uniform fill and foundation soil conditions. Testing during and at the completion of grading will be required to confirm the engineering soil properties. Groundwater is in excess of 50 feet below ground surface and is not anticipated to impact the subject development.

3.2 Demolition of Existing Structures
Demolition of the three office buildings, existing utilities, walls and pavement will be performed prior to grading. We are anticipating a five-foot removal in the design fill areas and a five-foot over-excavation in the design cut areas. If any of the building foundations, underground utilities or retaining wall footings extend below the anticipated removal bottoms then the deeper areas need to be cleaned out of loose materials and replace with compacted fill to the depth of the anticipated removal bottom.

There will be large quantities of asphalt and concrete generated during demolition of the existing improvements. We understand this material will be exported offsite for disposal.

3.3 Site Preparation and Earthwork
General earthwork and grading specifications are provided below and in Appendix F. Grading will also have to satisfy the requirements of the City of Aliso Viejo. Prior to grading, deleterious material (highly organic topsoil, vegetation, trash, construction debris), if any, should be cleared from the site and disposed of offsite. The existing structures to be demolished and the buried utilities within the site should be removed, the loose soil cleaned out and the areas below the planned remedial removal bottoms be properly backfilled with compacted fill. The demolition operation should minimize disturbing/loosening existing soils and should protect existing improvements to remain.

Although not encountered during our limited exploration, there is the potential for cemented bedrock to be encountered locally in the deeper excavation that may be difficult to rip and may generate some oversize material (greater than 12 inches in diameter. Due to the shallow fills anticipated across the 1250
24074-02
November 25, 2025
251125 NMG VTTM Rpt 11
NMG
site, any oversize material generated will need to be crushed onsite prior to placement in fill or exported offsite.

We recommend a minimum of 5-foot-deep remedial removals in the design fill areas and 5-footdeep overexcavation in the design cut areas for the site to provide a new, uniform compacted fill blanket. Deeper remedial removals may be recommended during grading in areas where diatomaceous siltstone and claystone are encountered in removal bottoms to mitigate the potential for differential heave beneath building pads. The demolition operation and local variations in soil conditions may result in the need for deeper removals. Some of the existing utility lines may be locally deeper than the recommended remedial removals; therefore, special excavation for these lines may be necessary if encountered and backfilled accordingly with compacted fill.

Onsite materials that are relatively free of deleterious material should be suitable for use as compacted fill. Prior to placement of fill, the removal bottoms should be scarified a minimum of 6 inches, moisture-conditioned as needed, and compacted to minimum 90 percent relative compaction. The relative compaction should be based upon ASTM Test Method D1557-91.

The moisture content of the fill soil should be over optimum moisture content and consideration should be given to placing fill at higher moisture contents to facilitate the future presoaking process for slab-on-grade foundations. Fill material should be placed in loose lifts no greater than 8 inches in thickness and compacted prior to placement of the next lift. Ground sloping steeper than 5:1 (horizontal to vertical) should be prepared by benching into firm competent material as fill is placed.

If diatomaceous soils are encountered, additional measures may be needed to achieve compaction.

3.4 Infiltration
Due to the subsurface conditions of compacted fill over shallow, low-permeability bedrock, stormwater infiltration is not feasible at this site.

3.5 Settlement Potential
For preliminary foundation design purposes, we estimate total consolidation (static) settlement would not exceed 1 inch and differential settlement on the order of 1 inch over a span of 40 feet.

Additional evaluation of the settlement should be performed once a grading plan and structural loads become available.

3.6 Foundation and Slab Design Guidelines
Slab-on-grade foundations will be acceptable for the subject development. The design of shallow footings and slab-on-grade foundations will require collaboration between the geotechnical and structural engineers based on the anticipated structural loading conditions and considering the requirements of the 2025 CBC. For expansive soils, the CBC requires slab-on-grade foundations to be designed in accordance with the Post-Tension Institute (PTI) or Wire Reinforcement Institute (WRI) methodology. The foundation design for the shallow fill area will need to consider the potential for higher expansion and differential heave due to siltstone and claystone bedrock. This will be evaluated in more detail with the future design and during the site grading. 1251
24074-02
November 25, 2025
251125 NMG VTTM Rpt 12
NMG

3.7 Foundation Setbacks
The footings of structures located above descending slopes should be set back from the slope face in accordance with the minimum requirements of the City of Aliso Viejo, County of Orange, and 2025 CBC criteria, whichever is greater. The setback distance is measured from the outside edge of the footing bottom along a horizontal line to the face of the slope.

The tables below summarize the minimum setback criteria for structures above descending slopes:

Structural Setback Requirements
Building and Retaining Wall Footings
Above Descending Slopes
Slope Height [H] (feet) Minimum Setback
from Slope face (feet)
Less than 10 5
10 to 20 ½ * H
20 to 30 10
More than 30 ⅓ * H (maximum of 40')
For freestanding walls and other structures that are sensitive to lateral movement (e.g., smooth stucco finish, glass screens, etc.), NMG recommends that the structural setback requirements above be followed or that additional design measures be used to help control the potential for cracking and displacements.

Additionally, foundations for the new retaining wall above the existing retaining wall will need further evaluation for potential surcharge loading.

3.8 Seismic Design Guidelines
The following table summarizes the seismic design criteria for the subject site. The seismic design parameters are developed in accordance with 2025 CBC and ASCE 7-22. Due to the variable depths to bedrock across the overall site and the lack of shear wave velocities at depth, the seismic parameters were determined using the Default Site Class per ASCE 7-22. A geophysical study may be warranted in the future in order to obtain shear wave velocities in the upper 100 feet (Vs (30)) and determine the seismic site class.
1252
24074-02
November 25, 2025
251125 NMG VTTM Rpt 13
NMG
Selected Seismic Design Parameters
from 2025 CBC/ASCE 7-22
Seismic Design
Values
Reference
Latitude 33.5695 North
Longitude 117.7247 West
Controlling Seismic Source San Joaquin Hills USGS, 2025 Distance to Controlling Seismic Source 2.5 mi (4.1 km) USGS, 2025 Site Class per Table 20.3 and 11.4.2 of ASCE 7-22 Default SEA/OSHPD, 2025 Ss, Spectral Acceleration for Short Periods 1.41 g SEA/OSHPD, 2025 S1, Spectral Accelerations for 1-Second Periods 0.45 g SEA/OSHPD, 2025 SDS, Design Spectral Response Acceleration at Short
Periods from Equation 11.4-1 of ASCE 7-22 1.09 g SEA/OSHPD, 2025 SD1, Design Spectral Response Acceleration at 1-Second
Period from Equation 11.4-2 of ASCE 7-22 0.73 g SEA/OSHPD, 2025 TS, SD1/ SDS, Section 11.4.5.2 of ASCE 7-22 0.67 sec SEA/OSHPD, 2025 TL, Long-Period Transition Period 8 sec SEA/OSHPD, 2025 PGAM, Peak Ground Acceleration Corrected for Site
Class Effects from Equation 11.8.3 of ASCE 7-22 0.64 g SEA/OSHPD, 2025 Seismic Design Category, Section 11.6 of ASCE 7-22 D SEA/OSHPD, 2025

3.9 Pavement Design
We anticipate the future subgrade soils for pavements will have a minimum R-value of 20. Final structural pavement sections should be based on R-value testing after the completion of grading.

The following preliminary pavement sections are for the assumed traffic indices (TIs). The final structural pavement design should be based on the actual design TIs and the actual subgrade soil once the grading and utilities are completed. Lower R-values could be present if the fine grained bedrock ends up near the design pavement subgrade elevation.

Minimum Structural Pavement Section (Preliminary)
Location TI Composite Section Full-Depth Section
Parking Stalls 4.5 0.25' AC over 0.50' AB* 0.50' AC
Private Courts 5.5 0.35' AC over 0.60' AB 0.55' AC
Drives 6.0 0.35' AC over 0.65' AB 0.60' AC
AC = Asphalt Concrete; AB = Aggregate Base
*In accordance with County of Orange/City of Aliso Viejo design minimums.

Asphalt concrete should also be compacted to a minimum relative compaction of 95 percent. Please note that for two-stage paving operations, the initial based asphalt pavement layer should be a minimum of 0.25-foot AC and the final cap should be a minimum of 0.10 foot thick.

Prior to construction of pavement sections, the subgrade soils should be scarified to a minimum depth of 6 inches, moisture-conditioned as needed, and recompacted in place to a minimum of 90 percent relative compaction per ASTM D1557. The full-depth pavement area will require 1253
24074-02
November 25, 2025
251125 NMG VTTM Rpt 14
NMG
subgrade to have a minimum of 95 percent relative compaction in the upper 1 foot. Subgrade for the proposed pavements should be uniform, firm, and unyielding.

AB materials can be crushed aggregate base or crushed miscellaneous base in accordance with the Greenbook (Section 200-2). The materials should be free of any deleterious materials. Aggregate base materials should be placed in 6- to 8-inch-thick loose lifts, moisture-conditioned as necessary, and compacted to a minimum of 95 percent relative compaction (per ASTM D1557).

3.10 Exterior Concrete
The recommendations provided below should be used for design and construction measures of the concrete pavements/hardscape. These recommendations are considered minimum and may be superseded by more stringent requirements/standards of the City of Aliso Viejo, the Standard Specifications for Public Work Construction "Greenbook" or other designers. The public pavements and other exterior concrete improvements (within the street right-of-way) should be constructed in accordance with City of Aliso Viejo standards.

3.11 Soil Corrosivity and Cement Type
The soil soluble sulfates exposures at the site as found to vary from "negligible" to "severe" per Table 19.3.1.1 of ACI-318-19. The existing sandy fill is generally classified as "S0" and the clayey fill is classified as "S2". Finer grained bedrock soil is generally classified as "S2". The chloride levels within the soils are classified as Class C1. The chloride content in the bedrock exceeded 500 ppm. The onsite soils are corrosive to severely corrosive to ferrous metals.

Concrete mix requirements for structural concrete will require additional sulfate testing once the project grading is complete. Otherwise, the concrete mix requirements for structural concrete should be based on the "S2" exposure class. Table 19.3.2.1 in ACI-318-19 lists the appropriate type of cement, maximum water-cement ratio, and minimum concrete compressive strength. The city or other agency may have additional concrete requirements.

Structural concrete elements in contact with soil include footings and building slabs-on-grade.

Concrete improvements for streets, sidewalk and hardscape typically are not considered structural elements.

3.12 Pipelines, Trench Excavations, Temporary Shoring, and Backfill Excavations should conform to the latest edition of OSHA requirements (shoring or layback of trench or wall excavations). The near-surface soils across most of the site are anticipated to be classified as Type B in compacted fill soils (upper 5 feet) and Type C in bedrock (below a depth of 5 feet) for CalOSHA trenching and shoring excavation requirements. Excavations deeper than approximately 5 feet below existing ground surface will encounter siltstone and sandstone bedrock. The bedding conditions may be adverse to the trench wall and shoring may be needed during utility installation. Trench spoils should not be placed immediately adjacent to the trenches, especially on the up-dip side.
1254
24074-02
November 25, 2025
251125 NMG VTTM Rpt 15
NMG
The existing fill should generally be suitable for use as trench backfill. Excavations into bedrock may have chunky siltstone and cemented sandstone fragments and may need to be broken down to comply with trench backfill requirements. Backfill materials should not have rocks greater than 6 inches in the maximum dimension and should be compacted to a minimum relative compaction of 90 percent (per ASTM D1557). We recommend that moisture content of native backfill to be over optimum moisture content. Select backfill may be used in lieu of native soils.

If a high-density, polyethylene (HDPE) pipe is proposed for the development, then excavation, installation, bedding, shading, and backfilling should be in strict accordance with the project and manufacturer's requirements. HDPE pipe has specific requirements for the width of the trench excavation.
1255
24074-02
November 25, 2025
251125 NMG VTTM Rpt 16
NMG

4.0 PLANNING AND DESIGN RECOMMENDATIONS

1. The future rough grading plan should be reviewed by the geotechnical consultant once available, and specific recommendations provided as necessary for the project. Additional subsurface exploration and laboratory testing may be needed based on final design.

2. A geophysical survey may be needed in the future in order to properly determine the seismic site class based on the 2025 California Building Code.

3. A geotechnical rough grading plan review report should be prepared for the site-specific conditions and submitted to the City for their review and approval.

4. The model and production precise grading plans should be reviewed, and reports prepared to provide geotechnical recommendations and foundation design parameters in accordance with the most recent CBC code.

5. The structural and foundation plans, once available, should be reviewed to confirm the geotechnical parameters pertinent to the site are used for design.

6. The retaining and perimeter wall plans, once available, should be reviewed and recommendations provided for future design, grading, and construction. The existing retaining wall in the southeast corner that is tilting will need further evaluation.

7. Additional soil testing should be performed to confirm the final soil conditions related to the foundation design parameters after the completion of rough grading.

8. The street improvement and utility plans should be reviewed, and recommendations provided as needed. Trench excavations in the native bedrock may encounter friable material and/or adverse bedding that should be evaluated for safety compliance. 1256
24074-02
November 25, 2025
251125 NMG VTTM Rpt 17
NMG

5.0 LIMITATIONS
This report has been prepared for the exclusive use of our client, Shea Homes, within the specific scope of services requested by them for the subject residential development in Aliso Viejo, California. This report or its contents should not be used or relied upon for other projects or purposes or by other parties without the written consent of NMG and the involvement of a geotechnical professional. The means and methods used by NMG for this study are based on local geotechnical standards of practice, care, and requirements of governing agencies. No warranty or guarantee, express or implied is given.

The findings, conclusions, and recommendations herein are professional opinions based on interpretations and inferences made from geologic and engineering data from specific locations and depths, observed or collected at a given time. By nature, geologic conditions can vary from point to point, can be very different in between points, and can also change over time. Our conclusions and recommendations are subject to verification and/or modification during excavation and construction when more subsurface conditions are exposed. 1257
Chevron
SoCal Gas
Company -
Aliso Base
Autumnglen
Deerhurst
Journey
City Lights Dr
Barbados
Dr
Pacific Park Dr
Chevron
Aliso Viejo
Library
Ralphs
Western Digital
CVS Pharmacy
Staples
Shell
Del Taco
Circle K
Cafe río
PetSmart
Aliso Viejo
Journey
Liberty
Deerhurst
Aliso Viejo Pkwy
Orange County
Sheriff's
Department
Aliso Viejo
Station
Service Layer Credits: World Imagery: Vantor
World Topographic Map: County of Los Angeles, Bureau
of Land Management, Esri, HERE, Garmin, INCREMENT

P, USGS, METI/NASA, NGA, EPA, USDA
Hybrid Reference Layer: Sources: Esri, TomTom, Garmin,

PACIFIC CORPORATE PLAZA
27061 ALISO CREEK ROAD

SHEA HOMES DEVELOPMENT

CITY OF ALISO VIEJO, CALIFORNIA
Project Number: 24074-02
Project Name: Shea Aliso Viejo
Date: 11/25/2025
By: KGM/WG
Figure 1

SITE LOCATION MAP
P:\2024\24074-01 Shea Homes - DD\Drafting\GIS\SiteLocation.aprx 0 400
Feet
1 inch =400 feet ±
Subject Site
NMG
~
1258
Chevron
SoCal Gas
Company -
Aliso Base
rpus Christi
Catholic
Church
A
utu
m
nglen Deerhurst
Journey
City Lights Dr
Barbados Dr
P
acif
ic P
ark
Dr
Chevron
Aliso Viejo
Library
Ralphs
Western Digital
CVS Pharmacy
Staples
Shell
Del Taco
Circle K
Cafe río
Aliso ViejoJourney
Liberty
Aliso Viejo Pkwy
Orange County
Sheriff's
Department
Aliso Viejo
Station
Service Layer Credits: Hybrid Reference Layer: Sources:

Esri, TomTom, Garmin, FAO, NOAA, USGS, (c)
OpenStreetMap contributors, and the GIS User Community
World Imagery: Vantor
California Department of Conservation:
http://data-cadoc.opendata.arcgis.com/datasets/
SHEA HOMES RESIDENTIAL DEVELOPMENT 27181 ALISO CREEK ROAD TENTATIVE TRACK MAP 19442

CITY OF ALISO VIEJO, CALIFORNIA
Project Number: 24074-02 Project Name: Shea Aliso Viejo Date: 11/25/2025
By: KGM/WG Figure 2

SEISMIC HAZARD ZONE MAP
Source: https://maps.conservation.ca.gov/cgs/informationwarehouse/eqzapp/ Subject Site
P:\2024\24074-01 Shea Homes - DD\Drafting\GIS\SeismicHazards.aprx Legend
±
0 200 400
Feet
1 inch =400 feet
Liquefaction Zones
Landslide Zones
1111
CJ
NMG
~
1259
91 S18
Tustin
Santa Ana
Anaheim
Fullerton
Orange
Garden Grove
5 405
O r a n g e
Laguna Beach
Newport
Beach
Fountain
Valley
Costa Mesa
Irvine
261
91 15
Temescal
Valley
El Sobrante
74 74
405
Rancho Santa
Margarita
San Juan
Capistrano
Coto de Caza
Laguna Niguel
Mission Viejo
Lake Forest
Laguna Hills
Aliso Viejo
Service Layer Credits: Hybrid Reference Layer: Sources: Esri, TomTom, Garmin, FAO, NOAA, USGS, (c) OpenStreetMap contributors, and the GIS User Community
World Imagery: Earthstar Geographics
California Department of Conservation:
http://data-cadoc.opendata.arcgis.com/datasets/
b70a766a60ad4c0688babdd47497dbad_0
Subject Site
fault, approx. located
fault, approx. located, queried
fault, certain
fault, concealed
fault, concealed, queried
fault, inferred, queried
thrust fault, certain
thrust fault, approx. located
thrust fault, concealed
dextral fault, certain
dextral fault, approx. located
dextral fault, concealed
sinistral fault, certain
sinistral fault, approx. located
sinistral fault, concealed
thrust fault, certain (2)
thrust fault, approx. located (2)
thrust fault, concealed (2)
fault, certain (ball and bar)
fault, approx. located (ball and bar)
fault, concealed (ball and bar)
dextral fault, certain (ball and bar)
fault, concealed, queried (ball and bar)
fault, concealed, queried (ball and bar,
fault, certain (dip)
fault, approx. located (dip)
fault, concealed (dip)

SHEA HOMES RESIDENTIAL DEVELOPMENT
27181 ALISO CREEK ROAD
TENTATIVE TRACK MAP 19442

CITY OF ALISO VIEJO, CALIFORNIA
Project Number: 24074-01
Project Name: Shea Aliso Viejo
Date: 11/25/2025
By: KGM/WG
Figure 3

REGIONAL FAULT ACTIVITY MAP
Base: California Geological Survey, Fault Activity Map of California, 2010 O:\NMGGIS\Templates\ArcGIS PRO Templates\RegionalFault_20230420.aprx 0 10,000 20,000
Feet
1 inch =20,000 Feet ±
Quaternary
Late Quaternary
Holocene
Legend Regency of Movement

NEWPORT-INGLEWOOD

PELICAN-HILL

ELSINORE FAULT ZONE
-
-
-
NMG
~
1260
----
/ 0 I
390.J
I +390.6
i9.5
BASE MAP: PROACTIVE ENGINEERING
LEGEND

EARTH UNITS - CIRCLED WHERE BURIED
Af
Qal
Tc+Tm

ARTIFICIAL FILL

ALLUVIUM

INTERFINGERED CAPISTRANO AND MONTEREY FORMATION

SYMBOLS - LOCATIONS ARE APPROX/MA TE, QUERIED WHERE UNCERTAIN - - -• • • • • GEOLOGIC CONTACT, DOTTED WHERE BURIED
---F • • FAULT, DOTTED WHERE BURIED
--- t --- ANTICLINAL FOLD AXIS, SHOWING DIRECTION OF PLUNGE C ___ DESIGN CUT/ FILL/ EXISTING/ NATURAL LINE -0---0
F

OTHER SYMBOLS - LOCATIONS ARE APPROXIMATE
~H-6
T.D.11'
[email protected]'
[email protected]'
NoY.
•T-4
T.D.5' Tco@O'
OJGR-33
T.D.67'
•TR-21

HOLLOW-STEM AUGER BORING, SHOWING TOTAL DEPTH,

DEPTH TO EARTH UNIT AND DEPTH TO GROUNDWATER

GEOTECHNICAL TEST PIT THIS INVESTIGATION, SHOWING TOTAL

DEPTH AND DEPTH TO EARTH UNIT
PRIOR BORING BY JGR (1987) SHOWING TOTAL DEPTH
PRIOR GEOTECHNICAL TEST PIT BY JGR (1987)

GEOLOGIC ATTITUDES-LOCATIONS ARE APPROXIMATE, DASHED WHERE BURIED A li--------11 A I

BEDDING ATTITUDE

CROSS-SECTION
LIMITS OF EXISTING BULIDINGS (3 TOTAL)

GRAPHIC SCALE
20 4-0 80
( IN FEET )
1 inch = 40 ft.

PLATE 1

GEOTECHNICAL MAP
VESTING TENTATIVE TRACT MAP 19390
27181 ALISO CREEK ROAD

CITY OF ALISO VIEJO, CALIFORNIA
1-----------------~----~----------l
"' ctJ
(r,
CJ
-...J -Cc
::,
CJ
-...J
Q
Project No.: 24074-02 By: KGM/WG Project Name: Shea/Aliso Viejo DD ti, NMG 1
Date: 11/25/2025 SCALE: 1" = 40' Geotechnical, Inc.
1261
A A'
420
380 340
............... ___,____.__.____.__ __._ ............... -..+-+-..+-+---<-- •-- Existin~ t + t t t t t t t t t t .............................. _._ __._ ............... -..+-+-..+-+---<-- 1----+-+-+---+-+-++-+--+-+r r-i------1-i'f E~i~:i~~ 7 I 1 111 I Profile Proposed 1--1--11---1--1- 1--1--11---1--1- Retaining Existing T-3 + + + + + 1 Proi. _1_ 26, Retaining + + ~-__,_ ~--+-+- rrnvya[,11 rTp1asfT 11 • 111 l~xi:ti~g,~ire_1 • 11,
~¾tt -t1 vwa~ ~ (P~ot11:-o·)' j j It ~!-----+--+---+-+-+H--1::-~r~~~s~~ l _ _j_S!afiohL ~ 420 Tfff ~,tation Area ffir1 . nrr ::: ,_,_,_ F etammg + I + Desi n i i t + t t L L +-----+--+--+----I Wall + r t t t t t t t t t t t J~ t I Prn 1~0 ______ t
_
t
_
t -~ _ Existinq ____ LJ_ .J I I I I r I 380 I / v r "- t t + \ . 1 1 1 1 2-Story -LI I J LI --:-t±±tt-1 L flt t .............................. ___.___._ ___.__._-+--+-+ V ? ? ,,-- / >r>--.. ' --1..1---ll' 1 1 +, ,L -1Ltf f Office Build ng ___._1._ _l_l___Lff' t rf-W _ , _ / / ~0&-Y 9 .... gv T , , 1- ,,,.,v /+ /[),- ?f'jY;v' "-?-?---- -?_iU. ..:....U 11 .....JU. -?-+-- - .llj ?-' __ L - I t t f/ / / I Teo/" m' \ • I I • T r\--1-1 Cl Teo/Tm T~<t~1~)rr=ff1 1 ·1 I I I I 1---r==r~mL~ 1- h-:: 340 '/ " t t --· - --------- -It ~L!-t--~ 1urr= 'LLJ-Lt: _ _1:::1:cLLLLl + + +
+
! ! : 11 1 t : I ! ! : I ! ! : ! ! : [ [ : +1~~ ~t_;-"!!/~ J. T<,OfT~ 1 1............... ; --1--1--1---1 300 __._!.,___!._,____!,___!___!__.___j_____.!.,_____!,__,!__!__--i--__!____!__!.__!__-l----!,__!.,___!___cC---j___!___!____!,__,!_---+---!,____.!,__!__!._--+-__!,___!,_!.,___!__-+--,----'-------'--'----'----+----=---:---;--++-++-+-+-+-+-t-+-11-+-1-+-t-+-+-++-++-+--+--+-+-+-+-+-1 ++-+-+-t--300 I +--1-+--1-1--1--1-1
+ + + + + + + + + + + + + +
W-E
7 CROSS-SECTION A-A'
+ + + +
+ + + +
Project No.: 24074-02 Project Name: Shea Aliso Viejo
Date: 11/25/2025
+ + + +
BY:KGM/WG
SCALE: 1 "-40'
FIGURE 4
NMG
1262

APPENDIX A
1263
24074-02
November 25, 2025
251125 NMG VTTM Rpt A-1
NMG

APPENDIX A

REFERENCES
AMI_OC_84, 11929, 1984, Courtesy of UCSB Library Geospatial Collection. https://mil.library.ucsb.edu/ ap_indexes/FrameFinder/
AMI_OC_86, 12237, 1986, Courtesy of UCSB Library Geospatial Collection. https://mil.library.ucsb.edu/ap_indexes/FrameFinder/
California Department of Conservation, Division of Mines and Geology, 2000, Recommended Criteria for Delineating Seismic Hazard Zones: California Division of Mines and Geology, Special Publication 118, 12 p.

California Department of Conservation, Division of Mines and Geology, 2001, State of California Seismic Hazard Zones, San Juan Capistrano Quadrangle, Official Map Released December 21, 2001, Scale 1:24,000.

California Geological Survey (CGS), 2008, Guidelines for Evaluating and Mitigating Seismic Hazards in California, Special Publication 117, Originally Adopted March 13, 1997, Revised and Re-adopted September 11, 2008.

California Geological Survey (CGS), 2010, Fault Activity Map of California and Adjacent Areas (Scale 1: 750,000), Geologic Data Map No. 6, Compiled and Interpreted by Charles W.

Jennings and William Z. Bryant.

California Geological Survey (CGS), 2018, Earthquake Fault Zones, A Guide for Government Agencies, Property Owners / Developers, and Geoscience Practitioners for Assessing Fault Rupture Hazards in California, Special Publication 42, Revised 2018.

EAG_OC_93, 921, 1993, Courtesy of UCSB Library Geospatial Collection. https://mil.library.ucsb.edu/ap_indexes/FrameFinder/
Jack G. Raub Company, 1987, Preliminary Geotechnical Investigation, Planning Areas 52 and 26, Vesting Tentative Map Track T.T. 11795, Area Plan AP 86-21P, City of Aliso Viejo, California, dated April 15, 1987.

Morton, P.K., and Miller, R.V., 2006, Geologic map of the San Bernardino and Santa Ana 30' x 60' quadrangles, California, U.S. Geological Survey, Open-File Report OF-2006-1217, 1:100,000.

Morton, P.K., and Miller, R.V., 1981, Geologic Map of Orange County, California, showing mines and mineral deposits, California Division of Mines and Geology, Bulletin B-204, 1:48,000.

Netra Online, 2024, Historic Aerials, website address: https://www.historicaerials.com/viewer

1264
24074-02
November 25, 2025
251125 NMG VTTM Rpt A-2
NMG
REFERENCES (Continued)
Structural Engineers Association/Office of Statewide Health Planning and Development (SEA/OSHPD), 2025, U.S. Seismic Design Maps, web site address: https://seismicmaps.org/ U.S. Geological Survey (USGS), 2025, USGS Earthquake Hazard Toolbox, NSHM 2018 Dynamic Disaggregation and Hazard Curves Program; Date Accessed: November 13, 2025, web site address: https://earthquake.usgs.gov/nshmp/
1265

APPENDIX B
1266
Surface: Asphalt Pavement, 4.5" AC over 9" AB.

Artificial Fill (Af)
@ 1-5': Light olive brown clayey fine to coarse SAND, damp to moist, few sandstone/claystone clasts up to 1", trace roots, trace rusted metal, trace concrete, crystalline rock clast encountered @4.5'.
@ 5': Light olive brown clayey fine SAND, damp to moist, medium dense, few sandstone/siltstone clasts up to 1", FeO staining in bedrock fragments.
@ 10': Light olive brown clayey fine to medium SAND, damp to moist, medium dense to dense, few sandstone/siltstone clasts up to 1", FeO staining in bedrock fragments.
@ 15': Light olive brown clayey fine to medium SAND, moist, medium dense, few sandstone/siltstone clasts up to 1", FeO staining in bedrock fragments, some layers of more clay. @ 20': Grayish brown to yellowish brown clayey SILT to silty CLAY, moist to wet, very stiff, trace FeO and MnO staining, upper rings contain few sandstone/siltstone clasts up to 1/2".

SC
ML-CL
39 45
29 26
B-1
D-1
D-2
D-3
D-4
110.1
110.6
105.8

99.5 B-1 @ 1-5'

14.2 13.3

17.9 22.2
Date(s)
Drilled
Drilling
Company
Drill Rig
Type
Sampling
Method(s)
Approximate Groundwater Depth:

Comments Hand Augered First 5 Feet.

Modified California, Bulk
CME 75
2R Drilling
12/6/24 Logged
By
Drill Bit
Size/Type
Hammer
Data
8"
SHC
140 lbs @ 30 inch drop
Approximate Ground
Surface Elevation (ft)
Total Depth
Drilled (ft) 30.8
359.0 msl
Sheet 1 of 2
H- 1
No Groundwater Encountered
Type
Elevation (ft) SAMPLES OTHER
TESTS
and
REMARKS USCS Depth (ft) Moisture Content (%) Dry Density (pcf) MATERIAL DESCRIPTION Number Blows per foot Graphic Log
Aliso Viejo, CA
PROJECT NO. 24074-01

LOG OF BORING
Shea/ Aliso Viejo
0 5
10 15
20 25
350
340
Report: HOLLOW STEM; Project: 24074-01.GPJ; Data Template: NMG_GINT_2016.GDT; Printed: 11/18/25 1--------->-----I -------II
-
>-
~ NMG
1267
Tertiary Capistrano Formation, Oso Member (Tco)
@ 30': Upper: Grayish brown sandy SILTSTONE, damp, hard, trace clay laminations, trace MnO staining, minimal mica.

Lower: Light gray clean fine SANDSTONE, damp, very dense, trace FeO staining.

Notes:

Total Depth: 30.8 Feet.

No Groundwater Encountered.

Backfilled with Cuttings and Tamped.

Upper 6" Patched with Quick-Set Concrete and Black Dye.

ML
SC
D-5 90/10" 4.9 107.6
Shea/ Aliso Viejo Aliso Viejo, CA H- 1 Sheet 2 of 2
Template: HOLLOW STEM; Prj ID: 24074-01.GPJ; Printed: 11/18/25 Type
Elevation (ft) SAMPLES OTHER
TESTS
and
REMARKS USCS Depth (ft) Moisture Content (%) Dry Density (pcf) MATERIAL DESCRIPTION Number Blows per foot Graphic Log
Aliso Viejo, CA
PROJECT NO. 24074-01

LOG OF BORING
Shea/ Aliso Viejo
25 30
35 40
45 50
55 330
320
310
Report: HOLLOW STEM; Project: 24074-01.GPJ; Data Template: NMG_GINT_2016.GDT; Printed: 11/18/25 -. ______ -----+',...._.--:-7--=-+- •._--_1 (..+----+----+--------t ___________________________ J
I
>-
- -
- -
~ NMG
1268
Surface: Asphalt Pavement, 4" AC over 7" AB.

Artificial Fill (Af)
@ 1-5': Light grayish brown to olive yellow clayey fine to medium SAND , moist, few sandstone/siltstone clasts up to 1", trace FeO staining.
@ 5': Grayish brown fine sandy CLAY, wet, very stiff, few sandstone/siltstone clasts up to 1", trace FeO staining. @ 10': Light olive brown to orange sandy silty CLAY, wet, very stiff, few sandstone/siltstone clasts up to 1", trace medium to coarse sand, trace FeO staining.
@ 15': Brownish yellow clayey fine to medium SAND, damp, dense, few sandstone/siltstone clasts up to 1", trace FeO and MnO staining.
@ 20': Light olive brown clayey fine SAND, damp, dense, trace to few sandstone/siltstone clasts up to 1", trace FeO staining.

SC
CL
SC
34 25
61 50
B-1
D-1
D-2
D-3
D-4

85.4 96.4
116.1
109.3
B-1 @ 1-5'

34.6 -200, AL, CN

26.6 9.2

9.6 Date(s)
Drilled
Drilling
Company
Drill Rig
Type
Sampling
Method(s)
Approximate Groundwater Depth:

Comments Hand Augered First 5 Feet.

Modified California, Bulk
CME 75
2R Drilling
12/6/24 Logged
By
Drill Bit
Size/Type
Hammer
Data
8"
SHC
140 lbs @ 30 inch drop
Approximate Ground
Surface Elevation (ft)
Total Depth
Drilled (ft) 50.9
352.0 msl
Sheet 1 of 2
H- 2
No Groundwater Encountered
Type
Elevation (ft) SAMPLES OTHER
TESTS
and
REMARKS USCS Depth (ft) Moisture Content (%) Dry Density (pcf) MATERIAL DESCRIPTION Number Blows per foot Graphic Log
Aliso Viejo, CA
PROJECT NO. 24074-01

LOG OF BORING
Shea/ Aliso Viejo
0 5
10 15
20 25
350
340
330
Report: HOLLOW STEM; Project: 24074-01.GPJ; Data Template: NMG_GINT_2016.GDT; Printed: 11/18/25 I
I
I
~ NMG
1269
@ 30':Upper: Black to dark Grayish brown silty CLAY to clayey SILT, damp to moist, hard, low plasticity, few sandstone/siltstone clasts up to 1", trace FeO and MnO staining.

Lower: Yellowish brown clayey fine SAND, damp to moist, dense, trace to few sandstone/siltstone clasts up to 1", trace FeO staining.

Quaternary Alluvium (Qal)
@ 40': Olive gray clayey fine to medium SAND, damp to moist, very dense, trace to few highly weathered sandstone/siltstone clasts up to 1", trace coarse sand, trace pinhole pores.

Tertiary Monterey Formation (Tm)
@ 50': Upper: Light gray diatomaceous SILTSTONE, wet, hard, trace joints, trace fish scales, well bedded.

Lower: Light yellowish brown silty fine SANDSTONE, wet, very dense, trace FeO staining, minimal mica, friable.

Notes:

Total Depth: 50.9 Feet.

No Groundwater Encountered.

Backfilled with Cuttings and Tamped.

Upper 6" Patched with Quick-Set Concrete and Black Dye.

ML-CL
SC
ML
SM
65 85/11"
70/11"
D-5
D-6
D-7
124.8
120.1

82.8 12.4

11.7 40.5
Shea/ Aliso Viejo Aliso Viejo, CA H- 2 Sheet 2 of 2
Template: HOLLOW STEM; Prj ID: 24074-01.GPJ; Printed: 11/18/25 Type
Elevation (ft) SAMPLES OTHER
TESTS
and
REMARKS USCS Depth (ft) Moisture Content (%) Dry Density (pcf) MATERIAL DESCRIPTION Number Blows per foot Graphic Log
Aliso Viejo, CA
PROJECT NO. 24074-01

LOG OF BORING
Shea/ Aliso Viejo
25 30
35 40
45 50
55 320
310
300
Report: HOLLOW STEM; Project: 24074-01.GPJ; Data Template: NMG_GINT_2016.GDT; Printed: 11/18/25 I I I ___________________________ J
I
___________________________ J I.+--+----+---------,
~ NMG
1270
Surface: Asphalt Pavement, 3" AC over 5" AB.

Artificial Fill (Af)
@ 1-2.5': Yellowish brown silty clayey fine SAND, damp, few sandstone/siltstone clasts up to 1", trace FeO staining.

Tertiary Monterey Formation (Tm)
@ 2.5': Grayish brown fine sandy CLAYSTONE, wet, stiff, moderately bedded, trace FeO staining, trace fish scales, diatomaceous.
@ 5' Upper: Grayish brown clayey fine SANDSTONE, wet, dense, moderately bedded, trace FeO and MnO staining, micaceous.

Lower: Light grayish brown very fine clean SANDSTONE, wet, dense, trace FeO and MnO staining, friable.
@ 10': Upper: Light grayish brown very fine clean SANDSTONE, dry to damp, dense, trace FeO and MnO staining, friable.

Lower: Light grayish brown silty CLAYSTONE, damp, hard, low plasticity, trace fish scales, trace FeO and MnO staining.

Notes:

Total Depth: 11.5 Feet.

No Groundwater Encountered.

Backfilled with Cuttings and Tamped.

Upper 6" Patched with Quick-Set Concrete and Black Dye.

SC
CL
SC
SP
CL
18 68
56 B-1
D-1
D-2
D-3

86.4 90.1
112.7
B-1 @ 1-2.5'

32.9 27.7

4.2 Date(s)
Drilled
Drilling
Company
Drill Rig
Type
Sampling
Method(s)
Approximate Groundwater Depth:

Comments Hand Augered First 5 Feet.

Modified California, Bulk
CME 75
2R Drilling
12/6/24 Logged
By
Drill Bit
Size/Type
Hammer
Data
8"
SHC
140 lbs @ 30 inch drop
Approximate Ground
Surface Elevation (ft)
Total Depth
Drilled (ft) 11.5
355.0 msl
Sheet 1 of 1
H- 3
No Groundwater Encountered
Type
Elevation (ft) SAMPLES OTHER
TESTS
and
REMARKS USCS Depth (ft) Moisture Content (%) Dry Density (pcf) MATERIAL DESCRIPTION Number Blows per foot Graphic Log
Aliso Viejo, CA
PROJECT NO. 24074-01

LOG OF BORING
Shea/ Aliso Viejo
0 5
10 15
20 25
350
340
330
Report: HOLLOW STEM; Project: 24074-01.GPJ; Data Template: NMG_GINT_2016.GDT; Printed: 11/18/25 I ~~- ~ ---------------------- -
· .... '
·. :·.·.;
.. •. ·. ~
- -
\~ _____________ ___,r
\~ _____________ ___,
~ NMG
1271
Surface: Asphalt Pavement, 3" AC oer 5" AB.

Artificial Fill (Af)
@ 1': Grayish brown silty fine SAND, damp.
@ 2': Light gray clean fine SAND, damp, minimal mica, trace medium sand.

Tertiary Capistrano Formation, Oso member (Tco)
@ 5': Pale olive clean fine SANDSTONE, dense, dry to damp, minimal mica, friable.
@ 10': Pale olive clean fine to medium SANDSTONE, medium dense, dry to damp, trace coarse sand, minimal mica, trace FeO staining, friable.

Notes:

Total Depth: 11.5 Feet.

No Groundwater Encountered.

Backfilled with Cuttings and Tamped.

Upper 6" Patched with Quick-Set Concrete and Black Dye.

SM
SP
SP
53 38
B-1
D-1
D-2
110.8
108.2
B-1 @ 1-5'

2.1 2.3
Date(s)
Drilled
Drilling
Company
Drill Rig
Type
Sampling
Method(s)
Approximate Groundwater Depth:

Comments Hand Augered First 5 Feet.

Modified California, Bulk
CME 75
2R Drilling
12/6/24 Logged
By
Drill Bit
Size/Type
Hammer
Data
8"
SHC
140 lbs @ 30 inch drop
Approximate Ground
Surface Elevation (ft)
Total Depth
Drilled (ft) 11.5
354.0 msl
Sheet 1 of 1
H- 4
No Groundwater Encountered
Type
Elevation (ft) SAMPLES OTHER
TESTS
and
REMARKS USCS Depth (ft) Moisture Content (%) Dry Density (pcf) MATERIAL DESCRIPTION Number Blows per foot Graphic Log
Aliso Viejo, CA
PROJECT NO. 24074-01

LOG OF BORING
Shea/ Aliso Viejo
0 5
10 15
20 25
350
340
330
Report: HOLLOW STEM; Project: 24074-01.GPJ; Data Template: NMG_GINT_2016.GDT; Printed: 11/18/25 ~:
~-------------------------------
-
.·.··.'.··
- -
~ NMG
1272
Surface: Asphalt Pavement, 4" AC over 9" AB.

Artificial Fill (Af)
@ 1': Light olive brown fine SAND, damp, trace clay.
@ 3': Light olive brown silty clayey fine SAND, damp, trace sandstone/siltstone clasts up to 1".

Tertiary Monterey Formation (Tm)
@ 3.5': Thinly bedded very dark gray SILTSTONE clasts in cuttings, damp.
@ 5': Upper: Very dark gray clayey SILTSTONE, wet, hard, moderately bedded, diatomaceous.

Lower: Light olive brown very fine sandy SILTSTONE/silty very fine SANDSTONE, moist to wet, hard/dense, minimal mica.
@ 8.5 Increase in clay content.
@ 10': Upper: Very dark gray cemented SILTSTONE, moist, hard, highly oxidized w/ FeO staining, 3" claystone layer in upper three rings.

Lower: Pale yellow silty very fine SANDSTONE, dense to very dense, moist, moderately bedded, trace FeO and MnO staining, minimal mica.

Notes:

Total Depth: 11 Feet.

No Groundwater Encountered.

Backfilled with Cuttings and Tamped.

Upper 6" Patched with Quick-Set Concrete and Black Dye.

SP
SC
ML
SM-ML
ML
SC
62 63
B-1
D-1
D-2

93.0 101.2
B-1 @ 1-5', GS,

AL,MD, EI, CC, DS

32.4 15.0
Date(s)
Drilled
Drilling
Company
Drill Rig
Type
Sampling
Method(s)
Approximate Groundwater Depth:

Comments Hand Augered First 5 Feet.

Modified California, Bulk
CME 75
2R Drilling
12/6/24 Logged
By
Drill Bit
Size/Type
Hammer
Data
8"
SHC
140 lbs @ 30 inch drop
Approximate Ground
Surface Elevation (ft)
Total Depth
Drilled (ft) 11.0
360.0 msl
Sheet 1 of 1
H- 5
No Groundwater Encountered
Type
Elevation (ft) SAMPLES OTHER
TESTS
and
REMARKS USCS Depth (ft) Moisture Content (%) Dry Density (pcf) MATERIAL DESCRIPTION Number Blows per foot Graphic Log
Aliso Viejo, CA
PROJECT NO. 24074-01

LOG OF BORING
Shea/ Aliso Viejo
0 5
10 15
20 25
360
350
340
Report: HOLLOW STEM; Project: 24074-01.GPJ; Data Template: NMG_GINT_2016.GDT; Printed: 11/18/25 -
t7.7).---------------------------------
• • ''----------------~{
.... -
~~~---n r =~--- ~---------------------------1 ~ ..... ~ t-:-::-:-=-:-
;_:/ ... ~
1-:--::-:---=-:-
·::::::.
~=:·.
; .. :/ ... ~ ~----=--~ - -~ - - - - - - - - - - - - - - - - - - - - - - - - - - - - -1 ~::z---n ,. -L---+-----11'-" _. ~-+-----+,\ ___________________________ J .+---+--+----------, ~ NMG
1273
Surface: Asphalt Pavement, 4" AC over 8" AB.

Artificial Fill (Af)
@ 1-5': Light brown to light gray clayey fine SAND, moist, few sandstone/siltstone clasts up to 1".
@ 5': Olive yellow clayey fine to medium SAND, moist, medium dense, few siltstone clasts up to 1", trace FeO and MnO staining. @ 10': Mottled yellowish brown and light olive gray clayey medium to coarse SAND, damp to moist, medium dense, orange clayey coarse sand in upper rings.
@15': Light yellowish brown silty fine to medium SAND, moist to wet, medium dense, few siltstone clasts up to 1", trace FeO staining.
@ 20': Upper: Light yellowish brown clayey SAND, damp, dense, few siltstone clasts up to 1".

Tertiary Capistrano Formation, Oso Member (Tco)
Lower: Light gray clean fine SANDSTONE, damp, very dense, abundant FeO staining, trace MnO staining, friable, minimal mica.

SC
SM
SC
SP
39 28
28 75/11"
B-1
D-1
D-2
D-3
D-4
109.4
113.8
101.6
105.9
B-1 @ 1-5', GS, AL, EI,
CC

18.1 12.7

22.8 6.1
Date(s)
Drilled
Drilling
Company
Drill Rig
Type
Sampling
Method(s)
Approximate Groundwater Depth:

Comments Hand Augered First 5 Feet.

Modified California, Bulk
CME 75
2R Drilling
12/6/24 Logged
By
Drill Bit
Size/Type
Hammer
Data
8"
SHC
140 lbs @ 30 inch drop
Approximate Ground
Surface Elevation (ft)
Total Depth
Drilled (ft) 30.9
361.0 msl
Sheet 1 of 2
H- 6
No Groundwater Encountered
Type
Elevation (ft) SAMPLES OTHER
TESTS
and
REMARKS USCS Depth (ft) Moisture Content (%) Dry Density (pcf) MATERIAL DESCRIPTION Number Blows per foot Graphic Log
Aliso Viejo, CA
PROJECT NO. 24074-01

LOG OF BORING
Shea/ Aliso Viejo
0 5
10 15
20 25
360
350
340
Report: HOLLOW STEM; Project: 24074-01.GPJ; Data Template: NMG_GINT_2016.GDT; Printed: 11/18/25 -
...
~}7- ~,.____ ____ ____,;
(:/··;·
·.:·.·.;
(:i/
· ...
:::.-::.
~ NMG
1274
@ 30': Light gray clean fine SANDSTONE, dry to damp, very dense, abundant FeO staining, minimal mica, friable.

Notes:

Total Depth: 30.9 Feet.

No Groundwater Encountered.

Backfilled with Cuttings and Tamped.

Upper 6" Patched with Quick-Set Concrete and Black Dye.

SP D-5 84/11" 3.5 108.6
Shea/ Aliso Viejo Aliso Viejo, CA H- 6 Sheet 2 of 2
Template: HOLLOW STEM; Prj ID: 24074-01.GPJ; Printed: 11/18/25 Type
Elevation (ft) SAMPLES OTHER
TESTS
and
REMARKS USCS Depth (ft) Moisture Content (%) Dry Density (pcf) MATERIAL DESCRIPTION Number Blows per foot Graphic Log
Aliso Viejo, CA
PROJECT NO. 24074-01

LOG OF BORING
Shea/ Aliso Viejo
25 30
35 40
45 50
55 330
320
310
Report: HOLLOW STEM; Project: 24074-01.GPJ; Data Template: NMG_GINT_2016.GDT; Printed: 11/18/25 -
- -
- -
~ NMG
1275
-,
a.
(!)
..,. ~ "' J:
u
z
w
0::
>--
~
Project Name: Shea - Aliso Viejo Logged By: ASC
Project Number: 24074-02 Elevation: 361
NMG Equipment: John Deere 310SL Location: Northeast of Building K

GEOLOGIC
ATTITUDES DESCRIPTION: I DATE: 11/7/25
Surface: Fill Slope
Artificial Fill (Af)
@ 0-2': Olive gray and very dark gray clayey sandy SILT, damp, stiff, abundant roots up to 1.5-inches in diameter, abundant rootlets, scattered bedrock clasts comprised of siltstone and sandstone, weathered in the upper foot. @ 2'-5.5': Alternating layers of yellowish brown to olive brown clayey SAND and very dark brown sandy CLAY, moist, medium dense to dense/very stiff to hard, scattered rootlets and root hairs, abundant bedrock clasts up to 2-inches in diameter.

Notes:

Total Depth 5.5 Feet.

Partially Backfilled with Cuttings and Tamped.

Portion of Trench Left Open for Landscapers to Repair Electrical Lines for Irrigation.

GRAPHIC REPRESENTATION: West Wall SCALE: 1" = 3' SURFACE SLOPE: 24° ,- -
~
-f-
,- -- -f-
...... -- --
I-
- f-
.~ -- I ' I ' ' ' ' ' I ' I ' I I ' I ' ' ' ' ' ' ' I ' I -P---{ ~I , ~ ' o.' f I I I - -- - 11 I -- -
--
C> ( ', ~-: ( - (I -t 0 ~ - - I /
,) -- C I - / - - -{ .,,;;,r ·~ ,,. 0 -- ( o\ I
l:l.it.-1-r.c.ol"=:.. I I r_ __1/ 1-- -- LiAtS l=or -<- f-- - - ~~o-hotl\
--
1-- --
-
-
--
- fTRENCH NO.: ENGINEERING PROPERTIES T-1 Wt- >- ~ c.=- (/) w O:::z -I ci ~ci :Jw~ !;;~ e:, 0::: Cl) 0 GEOLOGIC (/) <Cz O z a. ::i oo w~ UNIT Cl) ~<.) Q ML SC/CL TREND: N4°E ---- ' I I I I I ' I ' ' I ' ' ' I I I I ' I ' ' ' -------- :J 0 . 5 G) 0 "Tl .., ::0 m z () :J: z q -;-I .... 1276
~
Project Name: Shea - Aliso Vieio Logged By: ASC TRENCH NO.: ENGINEERING PROPERTIES Project Number: 24074-02 Elevation: 363 T-2 W1- NMG Equipment: >-~c en w O:::z John Deere 310SL West of Building H ....I Location: c_j a.. • ::::>w~ 20 t;~~ 0::: Cl) u GEOLOGIC I DATE: 1117/25 GEOLOGIC en <Cz O z c. ::::i oo w~ ATTITUDES DESCRIPTION: UNIT Cl) 20 a Surface: Fill Slope
Artificial Fill (Af)
@ 0-1 .5': Yellowish brown to olive brown silty fine SAND, damp, medium dense, trace roots up to 1/4-inch in diameter, SM abundant root hairs and rootlets, scattered bedrock clasts composed of mostly sandstone with some siltstone, highly weathered with trace -
@ 1 ------------------------------------------------- .5'-5.5': Yellowish brown to olive brown silty SAND and grayish brown fine - sandy SILT, damp to moist, medium SM/ML dense/stiff, scattered rootlets and roothairs, scattered bedrock clasts. MB-1 Notes:

Total Depth 5.5 Feet.

Backfilled with Cuttings and Compacted with Backhoe-Mounted Compaction Wheel.

GRAPHIC REPRESENTATION: West Wall SCALE: 1" = 3' SURFACE SLOPE: 30° TREND: N25°W -
-
--
-
-
- -~ - ~ --
~
_,_
-
f-- - f- _,_
-
I I I I I I ' ' ' I I I ' I I I I I I I I I I ..,_ 'JU\ 'I '1' I I I I I I I I I ' I ' I I I ' I >-- - t- /2 f,F~ 1, I_ / I _,_ - -
--~1"
~ l' ~• , - - 1'\S-, •,_ c:::- -- -
-
.,, ( ~ ~'~·-·/ - - - ~ ..... r -~,_,!-r rot ~ - ( . ' - /
~ ' , ' /:;/ - - - Roo~
-
--
-
-
-
-
--
-
-
- -
- -
-
z
31:

G')
G')
(1)
0 ct
(")
::::r
:::s
(")
I» ~ -
:::s
(")
.
r0
G)
0 "T1
-I
::0
m
z
0 :I:
z
q ~
1277
...,

0..
(!) ~ ...

I:, ~ :r:
u
z
LlJ
Cr'.
t-
~
Project Name: Shea - Aliso Viejo Logged By: ASC TRENCH NO.: ENGINEERING PROPERTIES Project Number: 24074-02 Elevation: 363 T-3 UJ1- NMG (/) UJ C:::z >- John Deere 310SL West of Building D ....I >- !::: c;=- Equipment: Location: cj a. . ::J UJ ~ ::i!:o 1-t-~ c::: (/) u GEOLOGIC I GEOLOGIC (/) <( z ~z~ O z a. DATE: 11/7/25 :::j oo UJ~ ATTITUDES DESCRIPTION: UNIT (/) ::i1,0 0 Surface: Fill Slope
1: Bedding- Artificial Fill (Af)
N30"W/1 0"NE (N Wall)
2: Bedding A: Very dark brown clayey sandy SILT, dry to damp, medium stiff, abundant roots and rootlets, highly weathered. SM - N50°W/2°SW (S Wall) ~ ------------- -------------- ----------------------- 3: Bedding- Capistrano Formation, Oso Member (Teo) SM
N20"E/19"NW B: Reddish yellow silty fine SANDSTONE, Damp to moist, abundant FeO staining, bioturbations infilled with gray fine sandstone and highlighted with FeO staining.

C: Thinly bedded Olive gray SILTSTONE with trace fine reddish yellow SANDSTONE laminations, moist, very stiff to ML hard, Siltstone beds generally between 1/2- and 1-inch thick. Locally, Siltstone bed is undulatory in the upper foot.

Notes:

Total Depth 6.3 Feet.

Backfilled with Cuttings and Compacted with Backhoe-Mounted Compaction Wheel.

GRAPHIC REPRESENTATION: South Wall SCALE: 1" = 3' SURFACE SLOPE: 25° TREND: N85°E f- - >-
f'.~
~ ~~® -- - I- ->-
. . ..
-
-
~
.· . C - - ~ ~~-. .. , .. - - a .. - - - - I ' I I I I I I I I I •I • ' i • 1 I I I I I I I I I ' ' \ -:.._-.::::;:··.: ·· .. ' I I I I ' I I I - - • .. ·.: .•~~-- .. ... - r--- - ... , .. · .... r:-- -- - \
•. ·:-re~.·:._: .. -
.. -,- -
-,~ :.:®:: -· - - . + - -
.. ., . ; .. . , . • ' '--.:_". . . . - / ,-...
--
-
I- ->- ->-
-
,__
--
- >-
-
I- --
-
-
z
31:

G')
G')
CD
0 ....

CD
0 ':J'
:::s
0 -·
m ~ -
:::s
0 r
0 G)
0 "Tl
;ti
m
z
(")
:::t
z
q ~
1278
:;j: ~ "' ~ ~ -,
Cl.
(!)
N
9 v
r--
0 v
N
:c
(.)
z
w
a:
f-
~ Project Name:
- Project Number:

Shea - Aliso Vieio
24074-02
Logged By: _A~S~C _ __________ _
Elevation:
_
3~6~2
_ _ _______ ___ _ NMG Equipment:

GEOLOGIC

ATTITUDES
1: BeddingN4°E/16°NW
2: BeddingN1°W/15°NE
3: Fault- N26°E/66°SE
4: Fault- NB0 W/46°SW
5: Joint- N6°W/82°NE
John Deere 310SL Location: West of Building C
DESCRIPTION: DATE: 11/7/25
Surface: Cut Slope
Capistrano Formation, Oso Member (Teo)
A:Pale brownish yellow silty fine SANDSTONE, damp, dense, slightly micaceous, trace FeO staining.

B: Pale brownish gray to olive gray thinly bedded SILTSTONE, damp, very stiff to hard, trace laminations of pale gray fine SANDSTONE.

Faulting and Joints:Steeply dipping faults and joints were obseNed in the excavation. The faults were generally highlighted with FeO staining and had abundant rootlets and roothairs lining the surface. SILTSTONE within the trench had an apparen
Notes:

Total Depth 5 Feet.

Backfilled with Cuttings and Compacted with Backhoe-Mounted Compaction Wheel.

GRAPHIC REPRESENTATION: South Wall SCALE: 1" = 2' SURFACE SLOPE: 29° TRENCH NO.: ENGINEERING PROPERTIES
T-4

GEOLOGIC
UNIT
c,j
cj
c,j
:::i
SM
ML
TREND:
w Wt-
>- ~ c;=-- ...J O::z a. . ::::iw~ ~o t;!z~ a::: (I'.) 0 c(z O z o.. oo w~ (I'.) ~(..) 0 N85°E
z
:s:

G)
G)
(1)
0 -
(1)
(')
=r
::::,
(')
0)
::::,
(')
r0
G)
0 "Tl
-I
;o
m
z
C)
:r:
z
9 -t
I
.i:,,.
1279

APPENDIX C
1280
H- 1 D-1 5.0 354.0 39 125.8 110.1 14.2 72.4
H- 1 D-2 10.0 349.0 45 125.2 110.6 13.3 68.4
H- 1 D-3 15.0 344.0 29 124.7 105.8 17.9 81.6
H- 1 D-4 20.0 339.0 26 121.6 99.5 22.2 86.5
H- 1 D-5 30.0 329.0 90/10" 112.9 107.6 4.9 23.2
H- 2 D-1 5.0 347.0 34 115.0 85.4 34.6 96.1 59 41 16 CL CN H- 2 D-2 10.0 342.0 25 122.1 96.4 26.6 96.2
H- 2 D-3 15.0 337.0 61 126.8 116.1 9.2 55.0
H- 2 D-4 20.0 332.0 50 119.8 109.3 9.6 47.8
H- 2 D-5 30.0 322.0 65 140.2 124.8 12.4 95.3
H- 2 D-6 40.0 312.0 85/11" 134.2 120.1 11.7 78.4
H- 2 D-7 50.0 302.0 70/11" 116.3 82.8 40.5 100.0
H- 3 B-1 1.0 5.0 354.0 29 CC
H- 3 D-1 2.5 352.5 18 114.7 86.4 32.9 93.3
H- 3 D-2 5.0 350.0 68 115.0 90.1 27.7 86.0
H- 3 D-3 10.0 345.0 56 117.5 112.7 4.2 23.1
H- 4 D-1 5.0 349.0 53 113.1 110.8 2.1 11.1
H- 4 D-2 10.0 344.0 38 110.7 108.2 2.3 11.2
H- 5 B-1 1.0 5.0 359.0 102.6 26.7 45 11 32 11 SC 180 26 375 27.0 114.0 15.5 23 0.21 H- 5 D-1 5.0 355.0 62 123.2 93.0 32.4 100.0
H- 5 D-2 10.0 350.0 63 116.3 101.2 15.0 60.9
H- 6 B-1 1.0 5.0 360.0 30 8 28 9 SC 6 0.05 CC
H- 6 D-1 5.0 356.0 39 129.2 109.4 18.1 90.5
H- 6 D-2 10.0 351.0 28 128.3 113.8 12.7 71.3
H- 6 D-3 15.0 346.0 28 124.8 101.6 22.8 93.4
H- 6 D-4 20.0 341.0 75/11" 112.4 105.9 6.1 27.9
H- 6 D-5 30.0 331.0 84/11" 112.4 108.6 3.5 17.2
T-2 MB-1 3.0 360.0 CC
Printed: 11/24/25; Template: SUM_SOIL_LAB_ALL; Proj ID: 24074-01.GPJ Shea/ Aliso Viejo DD Aliso Viejo, CA

SUMMARY OF SOIL LABORATORY DATA
Sheet 1 of 1
Project Number: 24074-01

APPENDIX C
Boring/Sample Information
Boring
No.

Sample
No.

Depth
(feet) (feet)
Remarks
Soluble
Sulfate
Content
(% by wt)
Expansion R-Value
Index
Compaction
Optimum
Moisture
Content
(%)
Depth
Maximum
Dry
Density
(pcf)
Count
(N)
Direct Shear
Peak
Friction
Angle ( )
Cohesion
(psf)
Friction
Ultimate
Angle ( )
Cohesion
(psf)
USCS
Group
(%) Symbol
Atterberg
Limits
LL
(%)
PI
Content
(% pass.
2µ)
Hydrometer
Fines o o BlowClay
Sieve/
Content
(% pass.
#200)
Degree
of
Sat.
(%)
Field
Dry
Density
(pcf)
Field
Moisture
Content
(%)
Field
Density
(pcf)
End Wet
(feet)
Elevation
Geotechnical, Inc.
iii
NMG 1281
0 10
20 30
40 50
60 70
80 90
100
1,000 100 10 1 0.1 0.01 0.001
36 SIEVE OPENING IN INCHES
100 200 PERCENT PASSING
U.S. STANDARD

PARTICLE SIZE DISTRIBUTION
CL
SC
SC
Passing
2µ (%)
Passing
Sieve (%)
59 45
30 C
Activity
PI/-2µ Moisture Sample Depth(feet)

BOULDERS COBBLES
GRAVEL
coarse
LL
41 32
28 Field
35 16
11 9
11 8

1.00 1.13
6 SILT OR CLAY
1-1/2 3/4 3/8
fine
PARTICLE SIZE (mm)
Symbol PI u Cc No. 200 USCS
(%)
SAND
fine
U.S. STANDARD SIEVE NUMBERS HYDROMETER
12 8
coarse medium
3 4 16 30 50
Boring
Number
H- 2
H- 5
H- 6
Number
D-1
B-1
B-1

5.0 1.0 - 5.0

1.0 - 5.0
Shea/ Aliso Viejo DD
Aliso Viejo, CA
PROJECT NO. 24074-01
Template: NMSIV; Prj ID: 24074-01.GPJ; Printed: 1/10/25 Geotechnical, Inc.

I
0 IZI
~
I ~1 -------+-----------------i
I
I II
\
'

I II I I
I
I II
\
\
\
\
I
\
\
1 "'
NMG--=====================
1282
0 10
20 30
40 50
60 70
0 20 40 60 80 100 120

PLASTICITY CHART
LIQUID LIMIT(%)
PLASTICITY INDEX (%)

U-LINE A-LINE
CL- ML ML or OL
16 7
4 CL or OL
MH or OH
CH or OH
Shea/ Aliso Viejo DD
Aliso Viejo, CA
PROJECT NO. 24074-01
Template: NMATT; Prj ID: 24074-01.GPJ; Printed: 1/10/25 Geotechnical, Inc.

Symbol LL
41 32
28 Passing
No. 200
Sieve (%)
59 45
30 Description
Number
(Af) Pale gray sandy CLAY
(Af) Yellowish brown clayey SAND
(Af) Light brown clayey SAND
USCS
CL
SC
SC
PI
16 11
9 Boring
H- 2
H- 5
H- 6
Number
Sample Depth
(feet)
D-1
B-1
B-1

5.0 1.0 - 5.0

1.0 - 5.0
0 IZI
~
/ ,,, • v
••••• /:'::/ /:/:{:/ :/::::::::7
17 I
NMG--================= 1283
140 ,--,--,----.---,-..--..,.....-,-"'T'T"---,. \ \ \.

I\ \
Maximum Dry Density (pcf) 114.0
Optimum Moisture Content (%) 15.5
\ \ I\ G/S/F= 4 I 51 / 45
I\ \ \. 130 t--+--+--+--+--+--+--+--+--+->r,+--'!.-1'\-f-ll.\ t--+--+--+--+-+--+---+----+--+----+-'\--+l '\_-+-'1\-..+- \I\.-'\,. Zero Air Voids Curves 1---+--+--i------1f---l---1---1---+---+--+--+~I\.--P''\ -.-+-i\.~~ Gs = 2. 80 t-+--+--+--+--+--+--+--+--+--+--+---+-1 "'-'rl-----1\. \ Gs = 2. 70 120 i\":I"-<:~ Gs= 2.60
"~K .'\
C'
0 C.
>-
t::
en 110
z
w
0 >- V
a:::
0 100
90 t---t--+--t--;-+---t--+--+--i-+--+--+--t---if--+--+--+--+-f--+--+--+--+-l--+--+--+--+-+---1 80 0~..,___.__...__._5~..,___.__...__.___,1...,.o---1,_,___...___.__1 ... 5--'-.__..,___.__2 .... o----'-.__-'-....... -2 ... 5----'-..__-'-....... _.30 MOISTURE CONTENT (%)
Boring No. H- 5 Sample No. B-1 Depth: 1.0 - 5.0 ft
Sample Description: (Af) Yellowish brown clayey SAND uses: SC Liquid Limit: 32 J Plasticity Index: 11 Percent Passing 45 No. 200 Sieve:

Comments: 1557A
~

COMPACTION TEST RESULTS
Shea Homes DD
Aliso Viejo, CA
PROJECT NO. 24074-01
NMG Geotechnical Inc.

Template: NMCOMP _21; Prj ID: 24074-01.GPJ; Pnnted: 1/10/25 1284
-1
0 1
2 3
4 5
6 7
8 9
10 0.1 1 10 100

CONSOLIDATION TEST RESULTS
STRAIN (%)
STRESS (ksf)
Shea/ Aliso Viejo DD
Aliso Viejo, CA
PROJECT NO. 24074-01
Template: NMCONS; Prj ID: 24074-01.GPJ; Printed: 1/13/25 Geotechnical, Inc.

86.3 Degree of
Saturation (%)

89.7 98.7
Void
Ratio

0.966

0.952
Boring No. H- 2
Liquid Limit: 41 Plasticity Index: 16
Test
Sample Description:

Stage
Initial
USCS:

Percent Passing
Final
Moisture
Content (%)

32.1 34.8
Dry
Density (pcf)

85.7 Sample No. D-1
(Af) Pale gray sandy CLAY
No. 200 Sieve: 59
CL
Depth: 5.0 ft
LEGEND
= initial moisture
= after saturation
% Collapse (-)
or % Swell (+) +0.04
~
0 ~--+---+-+-+--+--------+-----+-+------+I •
- --- -,
-r-- ',
r---_ "'- - -----.

I
I I I
NMG--======
1285
0 1,000
2,000
3,000
4,000
5,000
0 1,000 2,000 3,000 4,000 5,000 6,000

DIRECT SHEAR TEST RESULTS
NORMAL STRESS (psf)
SHEAR STRENGTH (psf)
Shea/ Aliso Viejo DD
Aliso Viejo, CA
PROJECT NO. 24074-01
Template: NMDS; Prj ID: 24074-01.GPJ; Printed: 1/13/25
Geotechnical, Inc.

27.0 Cohesion (psf) 375 180
Parameter Peak Ultimate

SHEAR STRENGTH PARAMETERS
Sample Type: Remolded @ 90%RC Rate of Shear (in./min.):

26.7 102.6 Saturation (%):

Degree of 100
Liquid Limit: Percent Passing
Sample No. B-1
Final Moisture
Content (%):

Final Dry
Friction Angle (degrees) 26.0
32 Plasticity Index: 11 45 No. 200 Sieve:

Sample Description: (Af) Yellowish brown clayey SAND USCS: SC Boring No. H- 5

0.005
Density (pcf):

Depth: 1.0 - 5.0 ft
• 0
~ NMG--============== 1286
Sample
Compacted
Moisture
(%)
Compacted
Dry Density
(pcf)
Final
Moisture
(%)
Volumetric
Swell
(%)
Expansion
Index1
Value/Method
Expansive
Classification2
Soluble
Sulfate
(%)
Sulfate
Exposure3
H-5
B-1
1-5'

15.0 97.0 23.7 2.07 23 B Low 0.21 S2
H-6
B-1
1-5'

11.0 105.0 18.8 0.56 6 A Very Low 0.05 S0
Test Method:

ASTM D4829

HACH SF-1 (Turbidimetric)
Notes:

1. Expansion Index (EI) method of determination:
[A] E.I. determined by adjusting water content to achieve a 50 ±2% degree of saturation [B] E.I. calculated based on measured saturation within the range of 40% and 60%

2. ASTM D4829 (Classification of Expansive Soil)

3. ACI-318-14 Table 19.3.1.1 (Requirement for Concrete Exposed to Sulfate-Containing Solutions) Expansion Index
and Soluble
Sulfate
Test Results
(FRM001 Rev.5)
Project No. 24074-01
Project Name: Shea/ Aliso Viejo DD
~ NMG
1287
Sample ID
Resistivity
saturated
pH
Electrical
Conductivity
Table 1 - Laboratory Tests on Soil Samples
NMG Geotechnical, Inc.

Shea/Aliso Viejo
Keegan Labs #25-0203, Your #24074-02
19-Nov-25
Units
ohm-cm
mS/cm
T-2, MB-1 H-3, B-1
@ 3' @ 1-5'
322

7.0 2.04
573

7.6 0.51
H-6, B-1
@ 1-5'
1,660

7.7 0.10
Chemical Analyses (Total Salts)
Cations
sodium Na1+ mg/kg 1,051 459
ammonium NH41+ mg/kg ND ND
potassium Kl+ mg/kg 24 15
magnesium Mg2+ mg/kg 281 9.8
calcium Ca2+ mg/kg 898 31
Anions
carbonate C032- mg/kg ND ND
bicarbonate HCO/-mg/kg 21 92
fluoride Fl- mg/kg 5.4 5.6
chloride Cl i- mg/kg 1,061 505
nitrate N031- mg/kg 7.0 15
phosphate PO4 3- mg/kg 19 ND
sulfate SO4 2- mg/kg 5,220 437
Other Tests
sulfide s2- mg/kg na na
Redox mV na na
9- Moisture H2O 0 9-
0 na na
For test methods refer to Laboratory Test Methods attachment Conductivity in millisi emens/cm and chemical analyses were made mg/kg= milligrams per kilogram (parts per million) of dry soi l.

ND= not detected
na = not analyzed
on
465 W Alvarado St., Pomona, CA 91768
Phone: 9 51 -203-6581
89 ND

1. 4
0 ND
ND
43 7.0
44 7.1
ND
96 na
na
na
a 1:5 soil-to-water extract .
1288

APPENDIX D
1289
Announcement
ASCE 7-22 is now available.

OSHPD
Latitude, Longitude: 33.5695, -117.7247
Pacific Park Dr Pacific Park Dr Shell fl
'9 Sushi Kizuna
Journey
Q Aliso Viejo Ice Palace
~
in'
0 C')
...
(ti
(ti
'1'
;c
Q.
~
Foxborough Park 0
-
Q
Pacific Park Plaza Q
Map data ©2025
Date 11/13/2025, 2:47:14 PM
Design Code Reference Document
Risk Category
ASCE7-22
II
Site Class Default
Type Value Description (Data)
Ss 1.41 The MCER spectral response acceleration at 0.2 seconds for Site Class BC, in units of g.

S1
SMs
SM1
Sos
So1
Type
SDC

0.45 1.64

1.1 1.09

0.73 The MCER spectral response acceleration at 1 second for Site Class BC, in units of g.

SMs = 1.5 x Sos, the Risk-Targeted Maximum Considered Earthquake (MCER) spectral response acceleration for short periods (of the two-period spectrum) and the user-specified Site Class.

SM1 = 1.5 x S01 , the MCER spectral response acceleration for 1 second (of the two-period spectrum) and the user-specified Site Class.

The design spectral response acceleration for short periods (of the two-period spectrum) and the user-specified Site Class, in units of g.

The design spectral response acceleration for 1 second (of the two-period spectrum) and the user-specified Site Class, in units of g Value Description (Data Contd.)
D Seismic design category
PGAM 0.64 PGAM, the Geometric-Mean Maximum Considered Earthquake (MCEG) peak ground acceleration for the user-specified Site Class, in units of g Ts 0.672 Ts = S01/S0s, in seconds, for construction of the two-period design spectrum TO 0.134 TO = 0.2 x Ts, in seconds, for construction of the two-period design response spectrum 8 TL• the long-period transition period, in seconds, for construction of the two-period design response spectrum 1290
Type
PGAuh
PGA84th
Vs30
Spatial Interpolation
Method
PG~Floor
riskTargetedSpectrum
eightyFourthSpectrum
Value
See underlying data for Site
Classes C, CD, and D
See underlying data for Site
Classes C, CD, and D
260
linearloglinear
Description (Underlying Data and Metadata)
Probabilistic uniform-hazard (2%-in-50-years), geometric-mean peak ground acceleration, in units of g.

Deterministic 84th-percentile, geometric-mean peak ground acceleration (without deterministic lower limit), in units of g.

The shear-wave velocity used for the user-specified Site Class, in units of m/s Identifier for spatial interpolation method used to obtain values for location of interest from underlying gridded values: "linearloglinear" for bilinear of natural logarithm of values.

Deterministic lower limit peak ground acceleration (PGA8 ) for the user-specified Site Class, in units of g.

Probabilistic risk-targeted, maximum direction response spectrum (for 1 %-in-50-years collapse risk)
Deterministic 841h-percentile, maximum-direction response spectrum (without deterministic lower limit)
1291
Click to CORY.

Period
T(s)
0 Design Spectrum Ordinates (g)

0.48 0.01

0.02 0.03

0.05 0.075

0.1 0.15

0.2 0.25

0.3 0.4

0.5 0.75

1.5 2
3 4
5 7.5
10 Click to CORY.

Period T(s)
0 0.025

0.05 0.1

0.13 0.15

0.2 0.25

0.3 0.35

0.4 0.45

0.5 0.55

0.6 0.65

0.67 0.7

0.75 0.8

0.85 0.9

0.95 0.48

0.48 0.51

0.62 0.8

0.93 1.07

1.15 1.18

1.21 1.19

1.13 0.9

0.73 0.51

0.38 0.24

0.17 0.13

0.077

0.052
Design Spectrum Ordinates (g)

0.44 0.56

0.68 0.93

1.09 1.09

1.09 1.05

0.98 0.92

0.86 0.82

0.77 Multi Period
Two Period
MCER Spectrum Ordinates (g)

0.72 0.72

0.73 0.76

0.93 1.2

1.4 1.61

1.73 1.77

1.82 1.78

1.69 1.35

1.1 0.77

0.57 0.36

0.25 0.19

0.12 0.079
MCER Spectrum Ordinates (g)

0.66 0.84

1.02 1.39

1.64 1.64

1.64 1.57

1.47 1.38

1.3 1.22

1.16 1292
Period T(s) Design Spectrum Ordinates (g) MCER Spectrum Ordinates (g) 1 0.73 1.1

1.05 0.7 1.05

1.1 0.67

1.15 0.64 0.96

1.2 0.61 0.92

1.25 0.59 0.88

1.3 0.56 0.85

1.35 0.54 0.82

1.4 0.52 0.79

1.45 0.51 0.76

1.5 0.49 0.73

1.55 0.47 0.71

1.6 0.46 0.69

1.65 0.44 0.67

1.7 0.43 0.65

1.75 0.42 0.63

1.8 0.41 0.61

1.85 0.4 0.6

1.9 0.39 0.58

1.95 0.38 0.56
2 0.37 0.55

2.05 0.36 0.54

2.1 0.35 0.52

2.15 0.34 0.51

2.2 0.33 0.5

2.25 0.33 0.49

2.3 0.32 0.48

2.35 0.31 0.47

2.4 0.31 0.46

2.45 0.3 0.45

2.5 0.29 0.44

2.55 0.29 0.43

2.6 0.28 0.42

2.65 0.28 0.42

2.7 0.27 0.41

2.75 0.27 0.4

2.8 0.26 0.39

2.85 0.26 0.39

2.9 0.25 0.38

2.95 0.25 0.37
3 0.24 0.37

3.05 0.24 0.36

3.1 0.24 0.36

3.15 0.23 0.35

3.2 0.23 0.34

3.25 0.23 0.34

3.3 0.22 0.33

3.35 0.22 0.33

3.4 0.22 0.32

3.45 0.21 0.32
1293
Period T(s) Design Spectrum Ordinates (g) MCER Spectrum Ordinates (g)

3.5 0.21 0.31

3.55 0.21 0.31

3.6 0.2 0.31

3.65 0.2 0.3

3.7 0.2 0.3

3.75 0.2 0.29

3.8 0.19 0.29

3.85 0.19 0.29

3.9 0.19 0.28

3.95 0.19 0.28
4 0.18 0.28

4.05 0.18 0.27

4.1 0.18 0.27

4.15 0.18 0.27

4.2 0.17 0.26

4.25 0.17 0.26

4.3 0.17 0.26

4.35 0.17 0.25

4.4 0.17 0.25

4.45 0.16 0.25

4.5 0.16 0.24

4.55 0.16 0.24

4.6 0.16 0.24

4.65 0.16 0.24

4.7 0.16 0.23

4.75 0.15 0.23

4.8 0.15 0.23

4.85 0.15 0.23

4.9 0.15 0.22

4.95 0.15 0.22
5 0.15 0.22

5.05 0.15 0.22

5.1 0.14 0.22

5.15 0.14 0.21

5.2 0.14 0.21

5.25 0.14 0.21

5.3 0.14 0.21

5.35 0.14 0.21

5.4 0.14 0.2

5.45 0.13 0.2

5.5 0.13 0.2

5.55 0.13 0.2

5.6 0.13 0.2

5.65 0.13 0.19

5.7 0.13 0.19

5.75 0.13 0.19

5.8 0.13 0.19

5.85 0.13 0.19

5.9 0.12 0.19

5.95 0.12 0.19
1294
Period T(s) Design Spectrum Ordinates (g) MCER Spectrum Ordinates (g) 6 0.12 0.18

6.05 0.12 0.18

6.1 0.12 0.18

6.15 0.12 0.18

6.2 0.12 0.18

6.25 0.12 0.18

6.3 0.12 0.17

6.35 0.12 0.17

6.4 0.11 0.17

6.45 0.11 0.17

6.5 0.11 0.17

6.55 0.11 0.17

6.6 0.11 0.17

6.65 0.11 0.17

6.7 0.11 0.16

6.75 0.11 0.16

6.8 0.11 0.16

6.85 0.11 0.16

6.9 0.11 0.16

6.95 0.11 0.16
7 0.1 0.16

7.05 0.1 0.16

7.1 0.1 0.16

7.15 0.1 0.15

7.2 0.1 0.15

7.25 0.1 0.15

7.3 0.1 0.15

7.35 0.1 0.15

7.4 0.099 0.15

7.45 0.099 0.15

7.5 0.098 0.15

7.55 0.097 0.15

7.6 0.097 0.14

7.65 0.096 0.14

7.7 0.095 0.14

7.75 0.095 0.14

7.8 0.094 0.14

7.85 0.094 0.14

7.9 0.093 0.14

7.95 0.092 0.14
8 0.092 0.14

8.05 0.091 0.14

8.1 0.09 0.13

8.15 0.088 0.13

8.2 0.087 0.13

8.25 0.086 0.13

8.3 0.085 0.13

8.35 0.084 0.13

8.4 0.083 0.12

8.45 0.082 0.12
1295
Period T{s)

8.5 8.55

8.6 8.65

8.7 8.75

8.8 8.85

8.9 8.95
9 Click to CORY.

Period T{s)
Design Spectrum Ordinates (g)

0.081

0.08 0.079

0.078

0.077

0.076

0.075

0.074

0.073

0.073
Risk Targeted Spectrum Ordinates (g)
Probabilistic & Deterministic

DISCLAIMER
MCER Spectrum Ordinates (g)

0.12 0.12

0.11 0.11

0.11 84th Spectrum Ordinates(g)
While the information presented on this website is believed to be correct, SEAOC /OSHPD and its sponsors and contributors assume no responsibility or liability for its accuracy. The material presented in this web application should not be used or relied upon for any specific application without competent examination and verification of its accuracy, suitability and applicability by engineers or other licensed professionals. SEAOC / OSHPD do not intend that the use of this information replace the sound judgment of such competent professionals, having experience and knowledge in the field of practice, nor to substitute for the standard of care required of such professionals in interpreting and applying the results of the seismic data provided by this website. Users of the information from this website assume all liability arising from such use. Use of the output of this website does not imply approval by the governing building code bodies responsible for building code approval and interpretation for the building site described by latitude/longitude location in the search results of this website. 1296
Disaggregation Report
Disaggregation
~ co
0 N
N
'°LO I,-
0 -C:
.2o '5.-
.0
·;::
-
C:

CLO
u
?s
•
.. •
•• ••
• • • • • •
• •• .•
•• ••
• • •
•
• •
• •
•
• •
■ s = (-oo .. -2.5)
■ s = (-2.5 .. -2)
■ s = (-2 .. -1.5)
s=(-1 5 .. -1)
□ s = (-1 .. -0.5)
□ s = (-0.5 .. 0)
□ s = (0 .. 0.5)
Ds=[0.5 .. 1)
□ s = (1 .. 1.5)
■ s = (1 .5 .. 2)
■ s = (2 .. 2.5)
■ s = (2.5 .. +oo)
1297
Geographical Disaggregation
Parameter Summary
Model: NSHM Conterminous U.S. 2023
Latitude: 33.5695 °
Longitude: -117. 724 7 °
Site Class: CD (Vs30 365)
Intensity Measure Type: PGA
Return Period: 2475 (2% in 50)
Component: Total
1298
Disaggregation Summary: Total
Disaggregation targets
Return period : 2475 yrs
Exceedance rate : 4.040e-4 yr-•
PGA ground motion : 6.223e-1 g
Totals
Binned : 1 00 %
Residual : 0 %
Trace : 0.12 %
Mode {largest m-r bin)
m : 7.47
r : 5.35 km
&0 : 0.01 a
Contribution : 11 . 79 %
Discretization
r: min = 0.0, max = 1000.0, l::.. = 20.0 km
m : min = 4.4, max = 9.4, l::.. = 0.2
& : min= -3.0, max= 3.0, l::.. = 0.5 a
Recovered targets
Return period : 2456. 1 29 yrs
Exceedance rate : 4.071 e-4 yr- 1
Mean (over all sources)
m : 6.83
r : 13.31 km
&0 : 0.91 a
Mode {largest m-r-e0 bin)
m : 7.47
r : 5.2 km
&0 : 0.17cr
Contribution : 3.68 %
Epsilon keys
&0: [-oo .. -2.5)
&1 : [-2.5 .. -2.0)
&2: [-2.0 .. -1.5)
&3: [-1.5 .. -1 .0)
&4: [-1.0 .. -0.5)
&5 : [-0.5 .. 0.0)
&6 : [0 .0 .. 0.5)
&7 : [0 .5 .. 1 .0)
&8 : [1 .0 .. 1 .5)
&9 : [1 .5 .. 2.0)
&10 : [2.0 .. 2.5)
&11 : [2.5 .. +oo]
1299
Disaggregation Contributions: Total
Source Set L+ Source Type m Eo Ion lat az %
WUS Branch Average FaultSystem 65.36
San Joaquin Hills (2) 4.08 7.27 -0.13 117.699°W 33.588°N 48.73 28.36 Newport - Inglewood (offshore) (3) 9.75 7.17 0.86 111.190•w 33.507°N 224.61 11.29 Elsinore (Glen Ivy) (1) 30.87 7.32 1.97 117_495•w 33.770"N 43.52 2.99 Chino (3) 29.55 7.43 1.70 117.571 ·w 33.821 "N 26.88 2.94 Compton (0) 33.54 7.60 1.60 118.043"W 33.703"N 296.72 2.58 Lausuen Knoll (2) 11.17 7.27 0.47 117.896"W 33.421 "N 223.96 2.42 San Joaquin Hills (1) 7.40 7.29 0.35 117.758"W 33.632"N 336.30 2.3 Palos Verdes (3) 33.58 7.30 2.06 118.019"W 33.394"N 234.54 1.94 Newport - Inglewood (offshore) (1) 11.11 6.92 1.16 117.837°W 33.535"N 249.95 1.79 Elsinore (stepover) (0) 35.07 7.35 2.07 117_373•w 33.685°N 68.36 1.01 WUS Branch Average (opt) Grid 34.64
PointSourceFinite: -117.725, 33.628 7.44 5.76 1.17 117_725•w 33.628°N 0.00 1.4 PointSourceFinite: -117.725, 33.61 0 6.24 5.70 1.01 117.725°W 33.610°N 0.00 1.39 PointSourceFinite: -117.725, 33.637 8.04 5.80 1.24 117_725•w 33.637°N 0.00 1.29 PointSourceFinite: -117.725, 33.619 6.82 5.73 1.09 111.125•w 33.619°N 0.00 1.26 PointSourceFinite: -117.725, 33.61 0 7.20 5.71 1.05 111.125•w 33.610°N 0.00 1.23 PointSourceFinite: -117.725, 33.646 8.68 5.84 1.31 117_725•w 33.646°N 0.00 1.22 PointSourceFinite: -117.725, 33.628 8.49 5.77 1.22 117.725°W 33.628°N 0.00 1.21 PointSourceFinite: -117.725, 33.601 5.74 5.67 0.93 117.725"W 33.601 'N 0.00 1.19 PointSourceFinite: -117.725, 33.583 4.88 5.68 0.77 117.725°w 33.583°N 0.00 1.17 PointSourceFinite: -117.725, 33.637 9.15 5.81 1.28 111.125•w 33.637°N 0.00 1.11 PointSourceFinite: -117.725, 33.583 5.52 5.69 0.80 111.125•w 33.583'N 0.00 1.1 PointSourceFinite: -117.725, 33.619 7.83 5.74 1.14 117_725•w 33.619°N 0.00 1.1 PointSourceFinite: -117.725, 33.655 9.29 5.90 1.36 117_725•w 33.655'N 0.00 1.07 PointSourceFinite: -117.725, 33.601 6.60 5.68 0.97 117_725•w 33.601 °N 0.00 1.07 PointSourceFinite: -117.725, 33.646 9.82 5.85 1.35 111.125•w 33.646°N 0.00 1.06 1300
Application Metadata
Application: Disaggregation
URL: https://earthquake.usgs.gov/nshmp/hazard/disagg
Repository: nshmp-apps
Version: 20.8.0
URL: https://code.usgs.gov/ghsc/nshmp/nshmp-apps
Repository : nshmp-haz
Version: 2.7.0
URL: https://code.usgs.gov/ghsc/nshmp/nshmp-haz
Repository : nshmp-lib
Version: 1.7.15
URL: https://code.usgs.gov/ghsc/nshmp/nshmp-lib
Repository : nshm-conus
Version: 6.1.1
URL: https://code.usgs.gov/ghsc/nshmp/nshms/nshm-conus
November 13, 2025, 02:41 PM
1301

APPENDIX E
1302

1.9 Ru
Value
Water
Surface
Phi
(°)
Cohesion
(psf)
Strength
Type
Unit Weight
(lbs/ft3) Color Material Name
150 27 None 0 Mohr- Coulomb Af 120200 30 None 0 Mohr- Coulomb Tco 120 Method Name Min FS
Janbu corrected 1.9
PL
RW

34.7 450 400 350 300
0 50 100 150 200 250 300
Analysis By

FEO/KGM
Analysis
Static, Slope H=35', RW at Toe
File Path & Name
P:\2024\24074-02 Shea Aliso Viejo\Slide2\A-A'' Design Slope.slmd Date
11/25/2025
Project Number
24074-02
Cross Section
Cross Section A-A', West Side
Project
Shea/Aliso Viejo
SLIDEINTERPRET 9.038
~~~hnical. Inc.-----------------------
1303

1.6 34.8
PL
RW
Ru
Value
Water
Surface
Phi
(°)
Cohesion
(psf)
Strength
Type
Unit Weight (lbs/
ft3) Color Material Name
180 30 None 0 Mohr- Coulomb P-Static Af 125250 35 None 0 Mohr- Coulomb P-Static Tco 125 Method Name Min FS
Janbu corrected 1.6

0.19 450 400 350 300
0 50 100 150 200 250 300
Analysis By

FEO/KGM
Analysis
P-Static, Slope H=35', RW at Toe
File Path & Name
P:\2024\24074-02 Shea Aliso Viejo\Slide2\A-A'' Design Slope.slmd Date
11/25/2025
Project Number
24074-02
Cross Section
Cross Section A-A', West Side
Project
Shea/Aliso Viejo
SLIDEINTERPRET 9.038
I 1~1 I I 11 I I
~~~hnical. lnc .-------------+----------1
1304

1.5 Ru
Value
Water
Surface
Phi
(°)
Cohesion
(psf) Strength Type Unit Weight (lbs/ ft3) Color Material Name 150 27 None 0 Mohr- Coulomb Af 120200 30 None 0 Mohr- Coulomb Tco 120

14.8 RW
RW
Method Name Min FS
Janbu corrected 1.5
400 350 300
250 275 300 325 350 375 400 425 450 475 500 525
Analysis By

FEO/KGM
Analysis
Static, Slope H=15', RW Top of Slope
File Path & Name
P:\2024\24074-02 Shea Aliso Viejo\Slide2\A-A'' East Side - Design Slope.slmd Date
11/25/2025
Project Number
24074-02
Cross Section
Cross Section A-A' East Side
Project
Shea/Aliso Viejo
SLIDEINTERPRET 9.038
-
-
I I I I/ - ) r' +
L ' 1~ [J -
T
-
-
-

I I I I I I I I I I I I I I I I I I I I I I I
~~~hnical. Inc.
1305

1.2 14.8
Ru
Value
Water
Surface
Phi
(°)
Cohesion
(psf)
Strength
Type
Unit Weight (lbs/
ft3) Color Material Name
180 30 None 0 Mohr- Coulomb P-Static Af 125250 35 None 0 Mohr- Coulomb P-Static Tco 125 RW RW

0.19 Method Name Min FS
Janbu corrected 1.2
400 350 300
250 275 300 325 350 375 400 425 450 475 500 525
Analysis By

FEO/KGM
Analysis
P-Static, Slope H=15', RW Top of Slope
File Path & Name
P:\2024\24074-02 Shea Aliso Viejo\Slide2\A-A'' East Side - Design Slope.slmd Date
11/25/2025
Project Number
24074-02
Cross Section
Cross Section A-A' East Side
Project
Shea/Aliso Viejo
SLIDEINTERPRET 9.038
- ,;
-
I )/ rr I I - • ' "--JI~ [J - If
-
-
-

I I I I I I I I I I I I I I I I I I I I I I I
~~~hnical. Inc.
1306

APPENDIX F
1307
O:\NMGDOC\Reports\Appendices\Appendix F - Grading Specifications.doc F-1

APPENDIX F

GENERAL EARTHWORK AND GRADING SPECIFICATIONS

1.0 General

1.1 Intent: These General Earthwork and Grading Specifications are for the grading and earthwork shown on the approved grading plan(s) and/or indicated in the geotechnical report(s). These Specifications are a part of the recommendations contained in the geotechnical report(s). In case of conflict, the specific recommendations in the geotechnical report shall supersede these more general Specifications. Observations of the earthwork by the project Geotechnical Consultant during the course of grading may result in new or revised recommendations that could supersede these specifications or the recommendations in the geotechnical report(s).

1.2 Geotechnical Consultant: Prior to commencement of work, the owner shall employ a geotechnical consultant. The geotechnical consultant shall be responsible for reviewing the approved geotechnical report(s) and accepting the adequacy of the preliminary geotechnical findings, conclusions, and recommendations prior to the commencement of the grading.

Prior to commencement of grading, the Geotechnical Consultant shall review the "work plan" prepared by the Earthwork Contractor (Contractor) and schedule sufficient personnel to perform the appropriate level of observation, mapping, and compaction testing.

During the grading and earthwork operations, the Geotechnical Consultant shall observe, map, and document the subsurface exposures to verify the geotechnical design assumptions. If the observed conditions are found to be significantly different than the interpreted assumptions during the design phase, the Geotechnical Consultant shall inform the owner, recommend appropriate changes in design to accommodate the observed conditions, and notify the review agency where required. Subsurface areas to be geotechnically observed, mapped, elevations recorded, and/or tested include natural ground after it has been cleared for receiving fill but before fill is placed, bottoms of all "remedial removal" areas, all key bottoms, and benches made on sloping ground to receive fill.

The Geotechnical Consultant shall observe the moisture-conditioning and processing of the subgrade and fill materials and perform relative compaction testing of fill to determine the attained level of compaction. The Geotechnical Consultant shall provide the test results to the owner and the Contractor on a routine and frequent basis.
1308
O:\NMGDOC\Reports\Appendices\Appendix F - Grading Specifications.doc F-2

1.3 The Earthwork Contractor: The Earthwork Contractor (Contractor) shall be qualified, experienced, and knowledgeable in earthwork logistics, preparation and processing of ground to receive fill, moisture-conditioning and processing of fill, and compacting fill. The Contractor shall review and accept the plans, geotechnical report(s), and these Specifications prior to commencement of grading. The Contractor shall be solely responsible for performing the grading in accordance with the plans and specifications.

The Contractor shall prepare and submit to the owner and the Geotechnical Consultant a work plan that indicates the sequence of earthwork grading, the number of "spreads" of work and the estimated quantities of daily earthwork contemplated for the site prior to commencement of grading. The Contractor shall inform the owner and the Geotechnical Consultant of changes in work schedules and updates to the work plan at least 24 hours in advance of such changes so that appropriate observations and tests can be planned and accomplished. The Contractor shall not assume that the Geotechnical Consultant is aware of all grading operations.

The Contractor shall have the sole responsibility to provide adequate equipment and methods to accomplish the earthwork in accordance with the applicable grading codes and agency ordinances, these Specifications, and the recommendations in the approved geotechnical report(s) and grading plan(s). If, in the opinion of the Geotechnical Consultant, unsatisfactory conditions, such as unsuitable soil, improper moisture condition, inadequate compaction, insufficient buttress key size, adverse weather, etc., are resulting in a quality of work less than required in these specifications, the Geotechnical Consultant shall reject the work and may recommend to the owner that construction be stopped until the conditions are rectified.

2.0 Preparation of Areas to be Filled

2.1 Clearing and Grubbing: Vegetation, such as brush, grass, roots, and other deleterious material shall be sufficiently removed and properly disposed of in a method acceptable to the owner, governing agencies, and the Geotechnical Consultant.

The Geotechnical Consultant shall evaluate the extent of these removals depending on specific site conditions. Earth fill material shall not contain more than 1 percent of organic materials (by volume). No fill lift shall contain more than 5 percent of organic matter. Nesting of the organic materials shall not be allowed.

If potentially hazardous materials are encountered, the Contractor shall stop work in the affected area, and a hazardous material specialist shall be informed immediately for proper evaluation and handling of these materials prior to continuing to work in that area.
1309
O:\NMGDOC\Reports\Appendices\Appendix F - Grading Specifications.doc F-3 As presently defined by the State of California, most refined petroleum products (gasoline, diesel fuel, motor oil, grease, coolant, etc.) have chemical constituents that are considered to be hazardous waste. As such, the indiscriminate dumping or spillage of these fluids onto the ground may constitute a misdemeanor, punishable by fines and/or imprisonment, and shall not be allowed.

2.2 Processing: Existing ground that has been declared satisfactory for support of fill by the Geotechnical Consultant shall be scarified to a minimum depth of 6 inches.

Existing ground that is not satisfactory shall be overexcavated as specified in the following section. Scarification shall continue until soils are broken down and free of large clay lumps or clods and the working surface is reasonably uniform, flat, and free of uneven features that would inhibit uniform compaction.

2.3 Overexcavation: In addition to removals and overexcavations recommended in the approved geotechnical report(s) and the grading plan, soft, loose, dry, saturated, spongy, organic-rich, highly fractured or otherwise unsuitable ground shall be overexcavated to competent ground as evaluated by the Geotechnical Consultant during grading.

2.4 Benching: Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical units), the ground shall be stepped or benched. Please see the Standard Details for a graphic illustration. The lowest bench or key shall be a minimum of 15 feet wide and at least 2 feet deep, into competent material as evaluated by the Geotechnical Consultant. Other benches shall be excavated a minimum height of 4 feet into competent material or as otherwise recommended by the Geotechnical Consultant. Fill placed on ground sloping flatter than 5:1 shall also be benched or otherwise overexcavated to provide a flat subgrade for the fill.

2.5 Evaluation/Acceptance of Fill Areas: All areas to receive fill, including removal and processed areas, key bottoms, and benches, shall be observed, mapped, elevations recorded, and/or tested prior to being accepted by the Geotechnical Consultant as suitable to receive fill. The Contractor shall obtain a written acceptance from the Geotechnical Consultant prior to fill placement. A licensed surveyor shall provide the survey control for determining elevations of processed areas, keys, and benches.
1310
O:\NMGDOC\Reports\Appendices\Appendix F - Grading Specifications.doc F-4

3.0 Fill Material

3.1 General: Material to be used as fill shall be essentially free of organic matter and other deleterious substances evaluated and accepted by the Geotechnical Consultant prior to placement. Soils of poor quality, such as those with unacceptable gradation, high expansion potential, or low strength shall be placed in areas acceptable to the Geotechnical Consultant or mixed with other soils to achieve satisfactory fill material.

3.2 Oversize: Oversize material defined as rock, or other irreducible material with a maximum dimension greater than 12 inches, shall not be buried or placed in fill unless location, materials, and placement methods are specifically accepted by the Geotechnical Consultant. Placement operations shall be such that nesting of oversized material does not occur and such that oversize material is completely surrounded by compacted or densified fill. Oversize material shall not be placed within 10 vertical feet of finish grade or within 2 feet of future utilities or underground construction.

3.3 Import: If importing of fill material is required for grading, proposed import material shall meet the requirements of Section 3.1. The potential import source shall be given to the Geotechnical Consultant at least 48 hours (2 working days) before importing begins so that its suitability can be determined and appropriate tests performed.

4.0 Fill Placement and Compaction

4.1 Fill Layers: Approved fill material shall be placed in areas prepared to receive fill (per Section 3.0) in near-horizontal layers not exceeding 8 inches in loose thickness. The Geotechnical Consultant may accept thicker layers if testing indicates the grading procedures can adequately compact the thicker layers. Each layer shall be spread evenly and mixed thoroughly to attain relative uniformity of material and moisture throughout.

4.2 Fill Moisture Conditioning: Fill soils shall be watered, dried back, blended, and/or mixed, as necessary to attain a relatively uniform moisture content at or slightly over optimum. Maximum density and optimum soil moisture content tests shall be performed in accordance with the American Society of Testing and Materials (ASTM Test Method D1557-91).

4.3 Compaction of Fill: After each layer has been moisture-conditioned, mixed, and evenly spread, it shall be uniformly compacted to not less than 90 percent of maximum dry density (ASTM Test Method D1557-91). Compaction equipment shall be adequately sized and be either specifically designed for soil compaction or of proven reliability to efficiently achieve the specified level of compaction with uniformity.
1311
O:\NMGDOC\Reports\Appendices\Appendix F - Grading Specifications.doc F-5

4.4 Compaction of Fill Slopes: In addition to normal compaction procedures specified above, compaction of slopes shall be accomplished by backrolling of slopes with sheepsfoot rollers at increments of 3 to 4 feet in fill elevation, or by other methods producing satisfactory results acceptable to the Geotechnical Consultant. Upon completion of grading, relative compaction of the fill, out to the slope face, shall be at least 90 percent of maximum density per ASTM Test Method D1557-91.

4.5 Compaction Testing: Field tests for moisture content and relative compaction of the fill soils shall be performed by the Geotechnical Consultant. Location and frequency of tests shall be at the Consultant’s discretion based on field conditions encountered. Compaction test locations will not necessarily be selected on a random basis. Test locations shall be selected to verify adequacy of compaction levels in areas that are judged to be prone to inadequate compaction (such as close to slope faces and at the fill/bedrock benches).

4.6 Frequency of Compaction Testing: Tests shall be taken at intervals not exceeding 2 feet in vertical rise and/or 1,000 cubic yards of compacted fill soils embankment. In addition, as a guideline, at least one test shall be taken on slope faces for each 5,000 square feet of slope face and/or each 10 feet of vertical height of slope. The Contractor shall assure that fill construction is such that the testing schedule can be accomplished by the Geotechnical Consultant. The Contractor shall stop or slow down the earthwork construction if these minimum standards are not met.

4.7 Compaction Test Locations: The Geotechnical Consultant shall document the approximate elevation and horizontal coordinates of each test location. The Contractor shall coordinate with the project surveyor to assure that sufficient grade stakes are established so that the Geotechnical Consultant can determine the test locations with sufficient accuracy. At a minimum, two grade stakes within a horizontal distance of 100 feet and vertically less than 5 feet apart from potential test locations shall be provided.

5.0 Subdrain Installation
Subdrain systems shall be installed in accordance with the approved geotechnical report(s), the grading plan, and the Standard Details. The Geotechnical Consultant may recommend additional subdrains and/or changes in subdrain extent, location, grade, or material depending on conditions encountered during grading. All subdrains shall be surveyed by a land surveyor/civil engineer for line and grade after installation and prior to burial. Sufficient time should be allowed by the Contractor for these surveys. 1312
O:\NMGDOC\Reports\Appendices\Appendix F - Grading Specifications.doc F-6

6.0 Excavation
Excavations, as well as over-excavation for remedial purposes, shall be evaluated by the Geotechnical Consultant during grading. Remedial removal depths shown on geotechnical plans are estimates only. The actual extent of removal shall be determined by the Geotechnical Consultant based on the field evaluation of exposed conditions during grading. Where fill-over-cut slopes are to be graded, the cut portion of the slope shall be made, evaluated, and accepted by the Geotechnical Consultant prior to placement of materials for construction of the fill portion of the slope, unless otherwise recommended by the Geotechnical Consultant.

7.0 Trench Backfills

7.1 Contractor shall follow all OHSA and Cal/OSHA requirements for safety of trench excavations.

7.2 Bedding and backfill of utility trenches shall be done in accordance with the applicable provisions of Standard Specifications of Public Works Construction.

Bedding material shall have a Sand Equivalent greater than 30 (SE>30). The bedding shall be placed to 1 foot over the top of the conduit and densified by jetting. Backfill shall be placed and densified to a minimum 90 percent of maximum from 1 foot above the top of the conduit to the surface, except in traveled ways (see Section 7.6 below).

7.3 Jetting of the bedding around the conduits shall be observed by the Geotechnical Consultant.

7.4 Geotechnical Consultant shall test the trench backfill for relative compaction. At least one test should be made for every 300 feet of trench and 2 feet of fill.

7.5 Lift thickness of trench backfill shall not exceed those allowed in the Standard Specifications of Public Works Construction unless the Contractor can demonstrate to the Geotechnical Consultant that the fill lift can be compacted to the minimum relative compaction by his alternative equipment and method.

7.6 Trench backfill in the upper foot measured from finish grade/subgrade within existing or future traveled way, shoulder, and other paved areas (or areas to receive pavement) should be placed to a minimum 95 percent relative compaction unless specified differently by the governing agency.
1313
NMG
Geotechnical, Inc.

TYPICAL FILL KEY ABOVE NATURAL SLOPE

MINIMUM STANDARD GRADING DETAILS

DESIGN FINISH GRADE
BROW
BERM

COMPETENT

MATERIAL
MAINTAIN 9' MIN. HORIZONTAL WIDTH

FROM SLOPE FACE TO BENCH/BACKCUT

NATURAL
GRADE

TOE OF SLOPE SHOWN

ON GRADING PLAN

PROJECTED SLOPE GRADIENT
(1:1 MAXIMUM)

BACKCUT -- VARIES
2' MINIMUM

KEY DEPTH

PLACE COMPACTED BACKFILL

TO ORIGINAL GRADE
MINIMUM 1' TILT BACK OR 2% SLOPE
(WHICHEVER IS GREATER)
NOTE: BENCHING SHALL BE REQUIRED WHEN NATURAL SLOPES ARE EQUAL TO OR STEEPER THAN 5:1 OR WHEN RECOMMENDED BY THE SOIL ENGINEER. WHERE THE

NATURAL SLOPE APPROACHES OR EXCEEDS THE DESIGN SLOPE RATIO, SPECIAL RECOMMENDATIONS WILL BE PROVIDED BY THE GEOTECHNICAL ENGINEER.

VARIABLE

COMPACTED FILL

KEY IN COMPETENT
MATERIAL. MINIMUM
WIDTH OF 15 FEET OR

AS RECOMMENDED BY

THE GEOTECHNICAL
CONSULTANT.

FIGURE 1
4' TYPICAL
8/96 FILL KEY ABOVE NAT. SLOPE.ai

REMOVE UNSUITABLE MATERIAL
--
1314
NMG
Geotechnical, Inc.

TYPICAL FILL ABOVE CUT SLOPE

MINIMUM STANDARD GRADING DETAILS
FIGURE 2

DESIGN FINISH GRADE COMPACTED FILL

COMPETENT

MATERIAL
BROW
BERM
4'

TYPICAL

CUT/FILL SHOWN ON

GRADING PLAN

NATURAL GRADE

CUT SLOPE TO BE CONSTRUCTED

PRIOR TO PLACEMENT OF FILL

TYPICAL HEIGHT OF BENCHES IS
4 FEET OR AS RECOMMENDED BY

THE GEOTECHNICAL CONSULTANT
MINIMUM 1' TILT BACK OR 2% SLOPE
(WHICHEVER IS GREATER)

VARIABLE

KEYWAY IN COMPETENT
MATERIAL. MINIMUM
WIDTH OF 15 FEET OR

AS RECOMMENDED BY

THE GEOTECHNICAL

CONSULTANT
2'
NOTE: THE FILL PORTION OF THE SLOPE SHALL BE COMPACTED
AS STATED IN THE PROJECT SPECIFICATIONS.
9' MIN.
8/03 TYP FILL ABOVE CUT SLOPE.ai

REMOVE UNSUITABLE MATERIAL
---
-- --
-- -- -- -- -- -- ::a,::

I
1315
NMG
Geotechnical, Inc.

TYPICAL BUTTRESS FILL

MINIMUM STANDARD GRADING DETAILS

TERRACE DRAIN
BROW
BERM

IN-PLACE EARTH MATERIAL
KEYWAY

COMPACTED FILL

BLANKET FILL IF RECOMMENDED

BY THE GEOTECHNICAL
CONSULTANT (3' TYPICAL)

DESIGN FINISH GRADE
30' MAX
W
D
MINIMUM 1' TILT BACK
OR 2 % SLOPE
(WHICHEVER IS GREATER)
2% TYP

SLOPE OF INTERFACE TO BE MAXIMUM PERMITTED

FOR SAFE WORKING CONDITIONS, AS RECOMMENDED
BY GEOTECHNICAL CONSULTANT. TYPICAL HEIGHT OF
BENCHES 4 FEET.

KEY IN COMPETENT
MATERIAL. MINIMUM

WIDTH (W) AND DEPTH (D)

OF BUTTRESS KEY AS

RECOMMENDED BY THE

GEOTECHNICAL
CONSULTANT.

NOTE: SUBDRAIN DETAILS, SEE FIGURE 5.

FIGURE 3
1/04 TYP BUTTRESS FILL.ai
---
---
f ----------
--------
-- --- --
-- - -- ---
I
1316
NMG
Geotechnical, Inc.

TYPICAL STABILIZATION FILL

MINIMUM STANDARD GRADING DETAILS

COMPETENT MATERIAL

ACCEPTABLE TO THE

GEOTECHNICAL CONSULTANT
TYPICAL HEIGHT OF BENCHES IS 4'

OR AS RECOMMENDED BY THE

GEOTECHNICAL CONSULTANT
MAINTAIN A 9' MINIMUM HORIZONTAL WIDTH

FROM SLOPE FACE TO BACKCUT OR BENCH
MINIMUM 1' TILT BACK
2' MIN.

KEY BOTTOM

COMPACTED FILL

TERRACE DRAIN

BLANKET FILL IF RECOMMENDED

BY THE GEOTECHNICAL
CONSULTANT (3' TYPICAL)
FIGURE 4
15' MINIMUM BACKCUT

AT TOP OF SLOPE

VARIABLE
15' MINIMUM

KEY WIDTH
9/96 STABILIZATION FILL.ai

DESIGN FINISH
GRADE
NOTE:

SEE FIGURE 5 FOR TYPICAL SUBDRAIN DETAILS FOR

STABILIZATION FILLS
1317
NMG
Geotechnical, Inc.

TYPICAL STABILIZATION AND BUTTRESS FILL SUBDRAINS

MINIMUM STANDARD GRADING DETAILS
OUTLETS TO BE SPACED AT 100'
MAXIMUM INTERVALS. EXTEND 12 INCHES

BEYOND FACE OF SLOPE AT TIME OF ROUGH
GRADING CONSTRUCTION.

DESIGN
FINISH
SLOPE
BROW
BERM

BLANKET FILL IF RECOMMENDED BY

GEOTECHNICAL CONSULTANT
(3' TYPICAL)
2' CLEAR
10' MIN
30' MAX

COMPACTED
FILL
2%
2%
4-INCH DIAMETER NON-PERFORATED OUTLET PIPE

TO BE LOCATED IN FIELD BY THE GEOTECHNICAL CONSULTANT
NOTE:

TRENCH FOR OUTLET PIPES TO BE
BACKFILLED WITH ON-SITE SOIL.
"FILTER MATERIAL" TO MEET

FOLLOWING SPECIFICATION
OR APPROVED EQUIVALENT.

SIEVE SIZE
1"
3/4"
3/8"
NO. 4
NO. 8
NO. 30
NO. 50
NO. 200

PERCENTAGE

PASSING
100
90-100
40-100
25-40
18-33
5-15
0-7
0-3
FILTER MATERIAL - MINIMUM OF THREE CUBIC FEET PER FOOT OF PIPE.

SEE FILTER MATERIAL SPECIFICATION.

ALTERNATE: IN LIEU OF FILTER MATERIAL, THREE CUBIC FEET OF GRAVEL PER FOOT OF SUBDRAIN (WITHOUT PIPE) MAY BE ENCASED IN FILTER FABRIC.

SEE GRAVEL SPECIFICATION, AND FIGURE 6 FOR

FILTER FABRIC SPECIFICATION
"GRAVEL" TO CONSIST OF 1/2" TO 1" CRUSHED ROCK

PER STANDARD SPECIFICATIONS FOR PUBLIC
WORKS CONSTRUCTION.

FILTER FABRIC SHALL BE LAPPED A MINIMUM OF 12 INCHES
ON ALL JOINTS.

MINIMUM 4-INCH DIAMETER SCHEDULE 40
ASTM D1527 OR D1785 OR SDR 35 ASTM D2751
OR D 3034. FOR FILL DEPTH OF 90 FEET OR
GREATER, USE ONLY SCHEDULE 40 OR
EQUIVALENT. THERE SHALL BE A MINIMUM OF
8 UNIFORMLY SPACED PERFORATIONS PER

FOOT OF PIPE INSTALLED WITH
PERFORATIONS ON BOTTOM OF PIPE.

PROVIDE CAP AT UPSTREAM END OF PIPE.

SLOPE AT 2 PERCENT TO OUTLET PIPE.

FIGURE 5

SEE DETAIL BELOW
DETAIL

OUTLET PIPE TO BE

CONNECTED TO

SUBDRAIN PIPE WITH

TEE OR ELBOW
8/96 STAB. BUTTRESS FILL SUBDRAINS.ai
30' MAX
I
1318
NMG
Geotechnical, Inc.

TYPICAL CANYON SUBDRAIN

MINIMUM STANDARD GRADING DETAILS
FIGURE 6
NOTES: DOWNSTREAM 20' OF PIPE AT OUTLET SHALL BE NON-PERFORATED AND BACKFILLED WITH

FINE-GRAINED MATERIAL
PIPE SHALL BE A MINIMUM OF 4-INCH DIAMETER. FOR RUNS OF 500 FEET OR MORE, USE 6-INCH

DIAMETER PIPE, OR AS RECOMMENDED BY THE GEOTECHNICAL CONSULTANT .

TYPICAL

BENCHING

SEE DETAIL BELOW

COMPETENT MATERIAL

NATURAL GRADE

FILTER FABRICS SHALL BE PERMEABLE NON-WOVEN POLYESTER, NYLON, OR POLYPROPYLENE MATERIAL CONFORMING TO THE FOLLOWING:
1) GRAB TENSILE STRENGTH. POUNDS, MIN. ASTM D 4632......................................................90 2) ELONGATION, AT PEAK LOAD, PERCENT, MIN. ASTM D 4632.................................................50 3) PUNCTURE STRENGTH, LBS., MIN. ASTM D 3787....................................................................45 4) COEFFICIENT OF WATER PERMITTIVITY, 1/SEC. ASTM D 4491............................................>0.7 5) BURST STRENGTH, P.S.I., MIN. ASTM D 3786..........................................................................180 6" MIN.
18" MIN.
3' TYPICAL

DEPTH AND

BEDDING MAY VARY

WITH PIPE AND LOAD
CHARACTERISTICS.
3' TYPICAL
DETAIL

FILTER MATERIAL - MINIMUM OF NINE CUBIC FEET PER FOOT
OF PIPE. SEE FIGURE 5 FOR FILTER MATERIAL SPECIFICATIONS.

ALTERNATE: IN LIEU OF FILTER MATERIAL, NINE CUBIC FEET OF

GRAVEL PER FOOT OF SUBDRAIN (WITHOUT PIPE) MAY BE
ENCASED IN FILTER FABRIC. SEE FIGURE 5 TO GRAVEL
SPECIFICATION. SEE ABOVE FOR FILTER FABRIC SPECIFICATION.

FILTER FABRIC SHALL BE LAPPED MINIMUM OF 12 INCHES ON
ALL JOINTS.

MINIMUM 4 INCH DIAMETER SCHEDULE 40 ASTM D 1527, OR
D 1785, OR SDR 35 ASTM 2751 OR D 3034. FOR FILL DEPTH OF 90 FEET OR GREATER, USE ONLY SCHEDULE 40 OR APPROVED
EQUIVALENT. THERE SHALL BE A MINIMUM OF 8 UNIFORMLY

SPACED PERFORATIONS PER FOOT OF PIPE INSTALLED WITH
PERFORATIONS ON BOTTOM OF PIPE.

COMPACTED FILL

MINIMUM

CLEARANCE

DIMENSIONS
Rev. 8/96 CANYON SUBDRAIN.ai

REMOVE UNSUITABLE MATERIAL
... ...
----
1319

TYPICAL OVERSIZE ROCK PLACEMENT METHOD

MINIMUM STANDARD GRADING DETAIL

FOR STRUCTURAL FILL
PLACE OVERSIZE MATERIAL IN TRENCH.

FALSE SLOPE OR CUT SLOT INTO APPROVED
MATERIAL. OVERSIZE MATERIAL MAY BE PLACED
SIDE BY SIDE IF SIZE PERMITS. (NOT TO EXCEED
A WIDTH OF 4 FEET)

FILL VOIDS WITH

SELECT GRANULAR

SOIL PLACED BY
WATER

DENSIFICATION

AND MECHANICAL
COMPACTION.

NESTING OR

STACKING OF

OVERSIZE

MATERIAL
IS NOT ACCEPTABLE.

FIGURE 7
4’
4’
4' MIN.
15' MIN.
15' MIN.

NOTES:

A) OVERSIZED ROCK IS DEFINED AS LARGER THAN 12" IN SIZE (IN GREATEST DIMENSION).

B) SPACE BETWEEN ROCKROWS SHOULD BE ONE EQUIPMENT WIDTH OR A MINIMUM OF 15 FEET.

C) THE WIDTH AND HEIGHT OF THE ROCKROW SHALL BE LIMITED TO FOUR FEET AND THE LENGTH LIMITED TO 300 FEET UNLESS APPROVED OTHERWISE BY THE GEOTECHNICAL CONSULTANT. OVERSIZE SHOULD BE PLACED WITH FLATEST SIDE ON THE BOTTOM.

D) OVERSIZE MATERIAL EXCEEDING FOUR FEET MAY BE PLACED ON AN INDIVIDUAL BASIS IF APPROVED BY THE GEOTECHNICAL CONSULTANT.

E) FILLING OF VOIDS WILL REQUIRE SELECT GRANULAR SOIL (SE > 20, OR LESS THAN 20 PERCENT FINES) AS APPROVED BY THE GEOTECHNICAL CONSULTANT. VOIDS IN THE ROCKROW TO BE FILLED BY WATER DENSIFYING GRANULAR SOIL INTO PLACE ALONG WITH MECHANICAL COMPACTION EFFORT.

F) IF APPROVED BY THE GEOTECHNICAL CONSULTANT, ROCKROWS MAY BE PLACED DIRECTLY ON COMPETENT MATERIALS OR BEDROCK, PROVIDED ADEQUATE SPACE IS AVAILABLE FOR COMPACTION.

G) THE FIRST LIFT OF MATERIAL ABOVE THE ROCKROW SHALL CONSIST OF GRANULAR MATERIAL AND SHALL BE PROOF-ROLLED WITH A D-8 OR LARGER DOZER OR EQUIVALENT.

H) ROCKROWS NEAR SLOPES SHOULD BE ORIENTED PARALLEL TO SLOPE FACE.

I) NESTING OR STACKING OF ROCKS IS NOT ACCEPTABLE.

FINISH GRADE

TYPICAL

ROCK ROW
FINISH
SLOPE
FACE
3/04 TYP OVERSIZE ROCK PLACEMENT.ai

PROFILE ALONG ROCKROW
300’ MAX.

SECTION THROUGH ROCKROW
4’ MAX.

NMG
Geotechnical, Inc.
10’ MIN.
10’ MIN.
4’
MAX.
4’
MAX.
1320
NMG
Geotechnical, Inc.

TYPICAL OVEREXCAVATION OF DAYLIGHT LINE

MINIMUM STANDARD GRADING DETAILS
FIGURE 8
NOTE: DEEPER THAN THE 3-FOOT OVEREXCAVATION MAY BE RECOMMENDED BY THE GEOTECHNICAL CONSULTANT IN STEEP TRANSITIONS.

COMPETENT MATERIAL ACCEPTABLE

TO THE GEOTECHNICAL CONSULTANT

OVEREXCAVATE AND RECOMPACT

UNSUITABLE

MATERIAL

NATURAL GRADE

COMPACTED FILL
5' MIN.

CUT LOT

OVEREXCAVATE AND RECOMPACT

UNSUITABLE

MATERIAL

NATURAL GRADE
COMPACTED FILL 3' MIN.

SEE NOTE
3' MIN.

SEE NOTE
5' MIN.

CUT FILL LOT (TRANSITION)

COMPETENT MATERIAL ACCEPTABLE

TO THE GEOTECHNICAL CONSULTANT

TYPICAL BENCHING

TYPICAL BENCHING
DESIGN

FINISH GRADE
DESIGN

FINISH GRADE
8/96 OVEREXCAVATION OF DAYLIGHT LINE.ai
----- -------- ----- ------- ------ ----- ---
I
1321
Preliminary Water Quality Management Plan (PWQMP)
Shea – Aliso Viejo

SHEA HOMES Appendix

Attachment F: SOCHM Model
1322
SOHM

PROJECT REPORT
1323
DRAFT
Aliso Viejo 1/9/2026 10:32:46 AM Page 2
General Model Information
Project Name: Aliso Viejo
Site Name:

Site Address: 2718 Aliso Creek Rd
City: Aliso Viejo
Report Date: 1/9/2026
Gage: Laguna Beach
Data Start: 10/01/1949
Data End: 09/30/2006
Timestep: 15 Minute
Precip Scale: 1.000
Version Date: 2021/05/25
POC Thresholds
Low Flow Threshold for POC1: 10 Percent of the 2 Year
High Flow Threshold for POC1: 10 Year
1324
DRAFT
Aliso Viejo 1/9/2026 10:32:46 AM Page 3
Landuse Basin Data
Predeveloped Land Use
Basin 1
Bypass: No
GroundWater: No
Pervious Land Use acre
D,Open Brush,VSteep 7.92
Pervious Total 7.92
Impervious Land Use acre
Impervious Total 0
Basin Total 7.92
Element Flows To:

Surface Interflow Groundwater
1325
DRAFT
Aliso Viejo 1/9/2026 10:32:46 AM Page 4
Mitigated Land Use
Basin 1
Bypass: No
GroundWater: No
Pervious Land Use acre
D,Urban,VSteep(>15%) 1.14
D,Urban,Flat(0-5%) 1.53
Pervious Total 2.67
Impervious Land Use acre
Impervious,Flat(0-5) 5.25
Impervious Total 5.25
Basin Total 7.92
Element Flows To:

Surface Interflow Groundwater
Vault 1 Vault 1
1326
DRAFT
Aliso Viejo 1/9/2026 10:32:46 AM Page 5
Routing Elements
Predeveloped Routing
1327
DRAFT
Aliso Viejo 1/9/2026 10:32:46 AM Page 6
Mitigated Routing
Vault 1
Width: 28 ft.

Length: 130 ft.

Depth: 5 ft.

Discharge Structure
Riser Height: 4 ft.

Riser Diameter: 54 in.

Notch Type: Rectangular
Notch Width: 4.186 ft.

Notch Height: 0.341 ft.

Orifice 1 Diameter: 1.45 in. Elevation:0 ft.

Element Flows To:

Outlet 1 Outlet 2
Vault Hydraulic Table
Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs)

0.0000 0.083 0.000 0.000 0.000

0.0556 0.083 0.004 0.013 0.000

0.1111 0.083 0.009 0.019 0.000

0.1667 0.083 0.013 0.023 0.000

0.2222 0.083 0.018 0.026 0.000

0.2778 0.083 0.023 0.030 0.000

0.3333 0.083 0.027 0.032 0.000

0.3889 0.083 0.032 0.035 0.000

0.4444 0.083 0.037 0.038 0.000

0.5000 0.083 0.041 0.040 0.000

0.5556 0.083 0.046 0.042 0.000

0.6111 0.083 0.051 0.044 0.000

0.6667 0.083 0.055 0.046 0.000

0.7222 0.083 0.060 0.048 0.000

0.7778 0.083 0.065 0.050 0.000

0.8333 0.083 0.069 0.052 0.000

0.8889 0.083 0.074 0.053 0.000

0.9444 0.083 0.078 0.055 0.000

1.0000 0.083 0.083 0.057 0.000

1.0556 0.083 0.088 0.058 0.000

1.1111 0.083 0.092 0.060 0.000

1.1667 0.083 0.097 0.061 0.000

1.2222 0.083 0.102 0.063 0.000

1.2778 0.083 0.106 0.064 0.000

1.3333 0.083 0.111 0.065 0.000

1.3889 0.083 0.116 0.067 0.000

1.4444 0.083 0.120 0.068 0.000

1.5000 0.083 0.125 0.069 0.000

1.5556 0.083 0.130 0.071 0.000

1.6111 0.083 0.134 0.072 0.000

1.6667 0.083 0.139 0.073 0.000

1.7222 0.083 0.143 0.074 0.000

1.7778 0.083 0.148 0.076 0.000

1.8333 0.083 0.153 0.077 0.000

1.8889 0.083 0.157 0.078 0.000

1.9444 0.083 0.162 0.079 0.000

2.0000 0.083 0.167 0.080 0.000
1328
DRAFT
Aliso Viejo 1/9/2026 10:32:46 AM Page 7

2.0556 0.083 0.171 0.081 0.000

2.1111 0.083 0.176 0.082 0.000

2.1667 0.083 0.181 0.084 0.000

2.2222 0.083 0.185 0.085 0.000

2.2778 0.083 0.190 0.086 0.000

2.3333 0.083 0.195 0.087 0.000

2.3889 0.083 0.199 0.088 0.000

2.4444 0.083 0.204 0.089 0.000

2.5000 0.083 0.208 0.090 0.000

2.5556 0.083 0.213 0.091 0.000

2.6111 0.083 0.218 0.092 0.000

2.6667 0.083 0.222 0.093 0.000

2.7222 0.083 0.227 0.094 0.000

2.7778 0.083 0.232 0.095 0.000

2.8333 0.083 0.236 0.096 0.000

2.8889 0.083 0.241 0.097 0.000

2.9444 0.083 0.246 0.097 0.000

3.0000 0.083 0.250 0.098 0.000

3.0556 0.083 0.255 0.099 0.000

3.1111 0.083 0.260 0.100 0.000

3.1667 0.083 0.264 0.101 0.000

3.2222 0.083 0.269 0.102 0.000

3.2778 0.083 0.273 0.103 0.000

3.3333 0.083 0.278 0.104 0.000

3.3889 0.083 0.283 0.105 0.000

3.4444 0.083 0.287 0.105 0.000

3.5000 0.083 0.292 0.106 0.000

3.5556 0.083 0.297 0.107 0.000

3.6111 0.083 0.301 0.108 0.000

3.6667 0.083 0.306 0.117 0.000

3.7222 0.083 0.311 0.329 0.000

3.7778 0.083 0.315 0.678 0.000

3.8333 0.083 0.320 1.123 0.000

3.8889 0.083 0.325 1.645 0.000

3.9444 0.083 0.329 2.234 0.000

4.0000 0.083 0.334 2.885 0.000

4.0556 0.083 0.338 3.511 0.000

4.1111 0.083 0.343 4.654 0.000

4.1667 0.083 0.348 6.134 0.000

4.2222 0.083 0.352 7.884 0.000

4.2778 0.083 0.357 9.866 0.000

4.3333 0.083 0.362 12.05 0.000

4.3889 0.083 0.366 14.42 0.000

4.4444 0.083 0.371 16.95 0.000

4.5000 0.083 0.376 19.63 0.000

4.5556 0.083 0.380 22.45 0.000

4.6111 0.083 0.385 25.38 0.000

4.6667 0.083 0.390 28.41 0.000

4.7222 0.083 0.394 31.52 0.000

4.7778 0.083 0.399 34.71 0.000

4.8333 0.083 0.403 37.95 0.000

4.8889 0.083 0.408 41.22 0.000

4.9444 0.083 0.413 44.52 0.000

5.0000 0.083 0.417 47.83 0.000

5.0556 0.083 0.422 51.12 0.000

5.1111 0.000 0.000 54.39 0.000
1329
DRAFT
Aliso Viejo 1/9/2026 10:32:46 AM Page 8
Analysis Results
POC 1
+ Predeveloped x Mitigated
Predeveloped Landuse Totals for POC #1
Total Pervious Area: 7.92
Total Impervious Area: 0
Mitigated Landuse Totals for POC #1
Total Pervious Area: 2.67
Total Impervious Area: 5.25
Flow Frequency Method: Cunnane
Flow Frequency Return Periods for Predeveloped. POC #1
Return Period Flow(cfs)
2 year 4.604602
5 year 5.788406
10 year 7.300378
25 year 9.762206
Flow Frequency Return Periods for Mitigated. POC #1
Return Period Flow(cfs)
2 year 4.542625
5 year 5.966315
10 year 6.624831
25 year 9.051075
730 ... , 1eu.-... ""' ..... " 1 ...
• ..
~

5.59 .., •• +..,::;,: ~~ .. , .. s 3.88 i
0 l " .. J
!I. 217
~ .,

0.46 IIE-5 lCE-4 10 100 .,.,. .... ... .. . P e.r c....,nt Tim -e E.x.cee.din g •• ' ' " " 30 " ,. • " .. • .... ' 1330
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 9
Duration Flows
The Facility PASSED
Flow(cfs) Predev Mit Percentage Pass/Fail

0.4605 3616 3530 97 Pass

0.5296 3266 3208 98 Pass

0.5986 2940 2934 99 Pass

0.6677 2642 2656 100 Pass

0.7368 2400 2380 99 Pass

0.8059 2175 2159 99 Pass

0.8750 1978 1958 98 Pass

0.9441 1819 1796 98 Pass

1.0132 1683 1646 97 Pass

1.0823 1553 1518 97 Pass

1.1514 1421 1370 96 Pass

1.2205 1306 1269 97 Pass

1.2895 1205 1179 97 Pass

1.3586 1107 1072 96 Pass

1.4277 1031 999 96 Pass

1.4968 958 922 96 Pass

1.5659 896 850 94 Pass

1.6350 827 784 94 Pass

1.7041 757 716 94 Pass

1.7732 711 651 91 Pass

1.8423 664 604 90 Pass

1.9114 602 561 93 Pass

1.9804 562 525 93 Pass

2.0495 520 482 92 Pass

2.1186 492 454 92 Pass

2.1877 467 429 91 Pass

2.2568 430 398 92 Pass

2.3259 398 370 92 Pass

2.3950 375 348 92 Pass

2.4641 355 327 92 Pass

2.5332 335 317 94 Pass

2.6023 314 302 96 Pass

2.6713 298 282 94 Pass

2.7404 282 268 95 Pass

2.8095 273 251 91 Pass

2.8786 261 236 90 Pass

2.9477 241 223 92 Pass

3.0168 227 207 91 Pass

3.0859 216 194 89 Pass

3.1550 204 179 87 Pass

3.2241 196 173 88 Pass

3.2932 183 167 91 Pass

3.3622 172 163 94 Pass

3.4313 164 153 93 Pass

3.5004 156 146 93 Pass

3.5695 146 139 95 Pass

3.6386 138 131 94 Pass

3.7077 129 126 97 Pass

3.7768 121 116 95 Pass

3.8459 118 109 92 Pass

3.9150 112 105 93 Pass

3.9841 106 100 94 Pass

4.0531 100 94 94 Pass
1331
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 10

4.1222 96 87 90 Pass

4.1913 90 80 88 Pass

4.2604 85 79 92 Pass

4.3295 81 73 90 Pass

4.3986 79 69 87 Pass

4.4677 73 67 91 Pass

4.5368 67 65 97 Pass

4.6059 66 59 89 Pass

4.6750 60 57 95 Pass

4.7440 57 53 92 Pass

4.8131 53 48 90 Pass

4.8822 49 44 89 Pass

4.9513 46 41 89 Pass

5.0204 45 40 88 Pass

5.0895 45 39 86 Pass

5.1586 42 38 90 Pass

5.2277 41 37 90 Pass

5.2968 39 34 87 Pass

5.3659 32 33 103 Pass

5.4349 29 29 100 Pass

5.5040 29 27 93 Pass

5.5731 27 26 96 Pass

5.6422 26 25 96 Pass

5.7113 23 23 100 Pass

5.7804 22 20 90 Pass

5.8495 22 20 90 Pass

5.9186 22 20 90 Pass

5.9877 22 19 86 Pass

6.0568 20 18 90 Pass

6.1258 19 16 84 Pass

6.1949 19 15 78 Pass

6.2640 18 14 77 Pass

6.3331 16 14 87 Pass

6.4022 16 13 81 Pass

6.4713 16 13 81 Pass

6.5404 15 13 86 Pass

6.6095 15 11 73 Pass

6.6786 14 10 71 Pass

6.7477 14 10 71 Pass

6.8167 14 10 71 Pass

6.8858 149 64 Pass

6.9549 149 64 Pass

7.0240 139 69 Pass

7.0931 129 75 Pass

7.1622 119 81 Pass

7.2313 119 81 Pass

7.3004 119 81 Pass
1332
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 11
Water Quality
1333
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 12
Model Default Modifications
Total of 0 changes have been made.

PERLND Changes
No PERLND changes have been made.

IMPLND Changes
No IMPLND changes have been made.
1334
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 13
Appendix
Predeveloped Schematic
1335
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 14
Mitigated Schematic
1336
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 15
Predeveloped UCI File
RUN
GLOBAL
WWHM4 model simulation
START 1949 10 01 END 2006 09 30
RUN INTERP OUTPUT LEVEL 3 0
RESUME 0 RUN 1 UNIT SYSTEM 1

END GLOBAL
FILES
<File> <Un#> <-----------File Name------------------------------>*** <-ID-> ***
WDM 26 Aliso Viejo.wdm
MESSU 25 PreAliso Viejo.MES
27 PreAliso Viejo.L61
28 PreAliso Viejo.L62
30 POCAliso Viejo1.dat

END FILES

OPN SEQUENCE
INGRP INDELT 00:15
PERLND 44
COPY 501
DISPLY 1

END INGRP

END OPN SEQUENCE
DISPLY
DISPLY-INFO1
# - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 MAX 1 2 30 9
END DISPLY-INFO1

END DISPLY
COPY

TIMESERIES
# - # NPT NMN ***
1 1 1
501 1 1

END TIMESERIES

END COPY
GENER
OPCODE
# # OPCD ***

END OPCODE
PARM
# # K ***

END PARM

END GENER
PERLND

GEN-INFO
<PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr ***
in out ***
44 D,Open Brush,VSteep 1 1 1 1 27 0

END GEN-INFO
*** Section PWATER***

ACTIVITY
<PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 44 0 0 1 0 0 0 0 0 0 0 0 0

END ACTIVITY

PRINT-INFO
<PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 44 0 0 4 0 0 0 0 0 0 0 0 0 1 9

END PRINT-INFO
1337
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 16
PWAT-PARM1
<PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 44 0 0 0 1 0 0 0 0 1 0 0
END PWAT-PARM1
PWAT-PARM2
<PLS > PWATER input info: Part 2 ***
# - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC
44 0 3.7 0.012 250 0.2 0.8 0.955
END PWAT-PARM2
PWAT-PARM3
<PLS > PWATER input info: Part 3 ***
# - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 44 40 35 4 2 0 0.03 0
END PWAT-PARM3
PWAT-PARM4
<PLS > PWATER input info: Part 4 ***
# - # CEPSC UZSN NSUR INTFW IRC LZETP ***
44 0 0.25 0.25 0.3 0.3 0
END PWAT-PARM4

MON-LZETPARM
<PLS > PWATER input info: Part 3 ***
# - # JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC *** 44 0.4 0.4 0.4 0.5 0.55 0.55 0.55 0.55 0.55 0.55 0.45 0.4

END MON-LZETPARM

MON-INTERCEP
<PLS > PWATER input info: Part 3 ***
# - # JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC *** 44 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12

END MON-INTERCEP
PWAT-STATE1
<PLS > *** Initial conditions at start of simulation
ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 ***
# - # *** CEPS SURS UZS IFWS LZS AGWS GWVS
44 0 0 0.025 0 0.74 0.3 0.01
END PWAT-STATE1

END PERLND
IMPLND

GEN-INFO
<PLS ><-------Name-------> Unit-systems Printer ***
# - # User t-series Engl Metr ***
in out ***

END GEN-INFO
*** Section IWATER***

ACTIVITY
<PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL ***

END ACTIVITY

PRINT-INFO
<ILS > ******** Print-flags ******** PIVL PYR
# - # ATMP SNOW IWAT SLD IWG IQAL *********

END PRINT-INFO
IWAT-PARM1
<PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI ***
END IWAT-PARM1
IWAT-PARM2
<PLS > IWATER input info: Part 2 ***
# - # *** LSUR SLSUR NSUR RETSC
END IWAT-PARM2
1338
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 17
IWAT-PARM3
<PLS > IWATER input info: Part 3 ***
# - # ***PETMAX PETMIN
END IWAT-PARM3
IWAT-STATE1
<PLS > *** Initial conditions at start of simulation
# - # *** RETS SURS
END IWAT-STATE1

END IMPLND

SCHEMATIC
<-Source-> <--Area--> <-Target-> MBLK ***
<Name> # <-factor-> <Name> # Tbl# ***
Basin 1***
PERLND 44 7.92 COPY 501 12
PERLND 44 7.92 COPY 501 13
******Routing******

END SCHEMATIC

NETWORK
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # ***

END NETWORK
RCHRES

GEN-INFO
RCHRES Name Nexits Unit Systems Printer ***
# - #<------------------><---> User T-series Engl Metr LKFG *** in out ***

END GEN-INFO
*** Section RCHRES***

ACTIVITY
<PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG ***

END ACTIVITY

PRINT-INFO
<PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR *********

END PRINT-INFO
HYDR-PARM1
RCHRES Flags for each HYDR Section ***
# - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * ***
END HYDR-PARM1
HYDR-PARM2
# - # FTABNO LEN DELTH STCOR KS DB50 ***
<------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2

HYDR-INIT
RCHRES Initial conditions for each HYDR section ***
# - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><--->

END HYDR-INIT

END RCHRES
1339
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 18

SPEC-ACTIONS

END SPEC-ACTIONS

FTABLES

END FTABLES

EXT SOURCES
<-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC
WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC
WDM 1 EVAP ENGL 1 PERLND 1 999 EXTNL PETINP
WDM 1 EVAP ENGL 1 IMPLND 1 999 EXTNL PETINP

END EXT SOURCES

EXT TARGETS
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL

END EXT TARGETS

MASS-LINK
<Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #***
MASS-LINK 12
PERLND PWATER SURO 0.083333 COPY INPUT MEAN
END MASS-LINK 12
MASS-LINK 13
PERLND PWATER IFWO 0.083333 COPY INPUT MEAN
END MASS-LINK 13

END MASS-LINK

END RUN
1340
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 19
Mitigated UCI File
RUN
GLOBAL
WWHM4 model simulation
START 1949 10 01 END 2006 09 30
RUN INTERP OUTPUT LEVEL 3 0
RESUME 0 RUN 1 UNIT SYSTEM 1

END GLOBAL
FILES
<File> <Un#> <-----------File Name------------------------------>*** <-ID-> ***
WDM 26 Aliso Viejo.wdm
MESSU 25 MitAliso Viejo.MES
27 MitAliso Viejo.L61
28 MitAliso Viejo.L62
30 POCAliso Viejo1.dat

END FILES

OPN SEQUENCE
INGRP INDELT 00:15
PERLND 64
PERLND 61
IMPLND 1
RCHRES 1
COPY 1
COPY 501
DISPLY 1

END INGRP

END OPN SEQUENCE
DISPLY
DISPLY-INFO1
# - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Vault 1 MAX 1 2 30 9
END DISPLY-INFO1

END DISPLY
COPY

TIMESERIES
# - # NPT NMN ***
1 1 1
501 1 1

END TIMESERIES

END COPY
GENER
OPCODE
# # OPCD ***

END OPCODE
PARM
# # K ***

END PARM

END GENER
PERLND

GEN-INFO
<PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr ***
in out ***
64 D,Urban,VSteep(>15%) 1 1 1 1 27 0
61 D,Urban,Flat(0-5%) 1 1 1 1 27 0

END GEN-INFO
*** Section PWATER***

ACTIVITY
<PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 64 0 0 1 0 0 0 0 0 0 0 0 0
61 0 0 1 0 0 0 0 0 0 0 0 0

END ACTIVITY
1341
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 20

PRINT-INFO
<PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 64 0 0 4 0 0 0 0 0 0 0 0 0 1 9
61 0 0 4 0 0 0 0 0 0 0 0 0 1 9

END PRINT-INFO
PWAT-PARM1
<PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 64 0 0 0 1 0 0 0 0 1 0 0
61 0 0 0 1 0 0 0 0 1 0 0
END PWAT-PARM1
PWAT-PARM2
<PLS > PWATER input info: Part 2 ***
# - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC
64 0 3.6 0.012 250 0.2 0.8 0.955
61 0 4.4 0.04 400 0.05 0.8 0.955
END PWAT-PARM2
PWAT-PARM3
<PLS > PWATER input info: Part 3 ***
# - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 64 40 35 4 2 0 0.03 0
61 40 35 4 2 0 0.03 0
END PWAT-PARM3
PWAT-PARM4
<PLS > PWATER input info: Part 4 ***
# - # CEPSC UZSN NSUR INTFW IRC LZETP ***
64 0 0.2 0.25 1 0.3 0
61 0 0.7 0.25 3 0.7 0
END PWAT-PARM4

MON-LZETPARM
<PLS > PWATER input info: Part 3 ***
# - # JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC *** 64 0.5 0.5 0.5 0.6 0.65 0.65 0.65 0.65 0.65 0.65 0.55 0.5 61 0.5 0.5 0.5 0.6 0.65 0.65 0.65 0.65 0.65 0.65 0.55 0.5

END MON-LZETPARM

MON-INTERCEP
<PLS > PWATER input info: Part 3 ***
# - # JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC *** 64 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 61 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12

END MON-INTERCEP
PWAT-STATE1
<PLS > *** Initial conditions at start of simulation
ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 ***
# - # *** CEPS SURS UZS IFWS LZS AGWS GWVS
64 0 0 0.02 0 0.72 0.3 0.01
61 0 0 0.07 0 0.88 0.3 0.01
END PWAT-STATE1

END PERLND
IMPLND

GEN-INFO
<PLS ><-------Name-------> Unit-systems Printer ***
# - # User t-series Engl Metr ***
in out ***
1 Impervious,Flat(0-5) 1 1 1 27 0

END GEN-INFO
*** Section IWATER***

ACTIVITY
<PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL ***
1 0 0 1 0 0 0

END ACTIVITY
1342
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 21

PRINT-INFO
<ILS > ******** Print-flags ******** PIVL PYR
# - # ATMP SNOW IWAT SLD IWG IQAL *********
1 0 0 4 0 0 0 1 9

END PRINT-INFO
IWAT-PARM1
<PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI ***
1 0 0 0 0 0
END IWAT-PARM1
IWAT-PARM2
<PLS > IWATER input info: Part 2 ***
# - # *** LSUR SLSUR NSUR RETSC
1 100 0.05 0.1 0.1
END IWAT-PARM2
IWAT-PARM3
<PLS > IWATER input info: Part 3 ***
# - # ***PETMAX PETMIN
1 0 0
END IWAT-PARM3
IWAT-STATE1
<PLS > *** Initial conditions at start of simulation
# - # *** RETS SURS
1 0 0
END IWAT-STATE1

END IMPLND

SCHEMATIC
<-Source-> <--Area--> <-Target-> MBLK ***
<Name> # <-factor-> <Name> # Tbl# ***
Basin 1***
PERLND 64 1.14 RCHRES 1 2
PERLND 64 1.14 RCHRES 1 3
PERLND 61 1.53 RCHRES 1 2
PERLND 61 1.53 RCHRES 1 3
IMPLND 1 5.25 RCHRES 1 5
******Routing******
PERLND 64 1.14 COPY 1 12
PERLND 61 1.53 COPY 1 12
IMPLND 1 5.25 COPY 1 15
PERLND 64 1.14 COPY 1 13
PERLND 61 1.53 COPY 1 13
RCHRES 1 1 COPY 501 16

END SCHEMATIC

END NETWORK
RCHRES

GEN-INFO
RCHRES Name Nexits Unit Systems Printer ***
# - #<------------------><---> User T-series Engl Metr LKFG *** in out ***
1 Vault 1 1 1 1 1 28 0 1

END GEN-INFO
1343
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 22
*** Section RCHRES***

ACTIVITY
<PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0

END ACTIVITY

PRINT-INFO
<PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9

END PRINT-INFO
HYDR-PARM1
RCHRES Flags for each HYDR Section ***
# - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * ***
1 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2
END HYDR-PARM1
HYDR-PARM2
# - # FTABNO LEN DELTH STCOR KS DB50 ***
<------><--------><--------><--------><--------><--------><--------> *** 1 1 0.02 0.0 0.0 0.5 0.0
END HYDR-PARM2

END HYDR-INIT

END RCHRES

SPEC-ACTIONS

END SPEC-ACTIONS

FTABLES
FTABLE 1
92 4
Depth Area Volume Outflow1 Velocity Travel Time***
(ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)***

0.000000 0.083563 0.000000 0.000000

0.055556 0.083563 0.004642 0.013448

0.111111 0.083563 0.009285 0.019018

0.166667 0.083563 0.013927 0.023293

0.222222 0.083563 0.018570 0.026896

0.277778 0.083563 0.023212 0.030071

0.333333 0.083563 0.027854 0.032941

0.388889 0.083563 0.032497 0.035580

0.444444 0.083563 0.037139 0.038037

0.500000 0.083563 0.041781 0.040344

0.555556 0.083563 0.046424 0.042526

0.611111 0.083563 0.051066 0.044602

0.666667 0.083563 0.055709 0.046585

0.722222 0.083563 0.060351 0.048488

0.777778 0.083563 0.064993 0.050318

0.833333 0.083563 0.069636 0.052084

0.888889 0.083563 0.074278 0.053792

0.944444 0.083563 0.078921 0.055448

1.000000 0.083563 0.083563 0.057055

1.055556 0.083563 0.088205 0.058619

1.111111 0.083563 0.092848 0.060141

1.166667 0.083563 0.097490 0.061627

1.222222 0.083563 0.102132 0.063077

1.277778 0.083563 0.106775 0.064494

1.333333 0.083563 0.111417 0.065882

1.388889 0.083563 0.116060 0.067240

1.444444 0.083563 0.120702 0.068572
1344
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 23

1.500000 0.083563 0.125344 0.069878

1.555556 0.083563 0.129987 0.071160

1.611111 0.083563 0.134629 0.072420

1.666667 0.083563 0.139272 0.073658

1.722222 0.083563 0.143914 0.074875

1.777778 0.083563 0.148556 0.076074

1.833333 0.083563 0.153199 0.077253

1.888889 0.083563 0.157841 0.078415

1.944444 0.083563 0.162483 0.079560

2.000000 0.083563 0.167126 0.080688

2.055556 0.083563 0.171768 0.081801

2.111111 0.083563 0.176411 0.082899

2.166667 0.083563 0.181053 0.083983

2.222222 0.083563 0.185695 0.085053

2.277778 0.083563 0.190338 0.086109

2.333333 0.083563 0.194980 0.087153

2.388889 0.083563 0.199622 0.088185

2.444444 0.083563 0.204265 0.089204

2.500000 0.083563 0.208907 0.090212

2.555556 0.083563 0.213550 0.091209

2.611111 0.083563 0.218192 0.092195

2.666667 0.083563 0.222834 0.093171

2.722222 0.083563 0.227477 0.094136

2.777778 0.083563 0.232119 0.095092

2.833333 0.083563 0.236762 0.096038

2.888889 0.083563 0.241404 0.096975

2.944444 0.083563 0.246046 0.097903

3.000000 0.083563 0.250689 0.098822

3.055556 0.083563 0.255331 0.099733

3.111111 0.083563 0.259973 0.100636

3.166667 0.083563 0.264616 0.101530

3.222222 0.083563 0.269258 0.102417

3.277778 0.083563 0.273901 0.103296

3.333333 0.083563 0.278543 0.104168

3.388889 0.083563 0.283185 0.105032

3.444444 0.083563 0.287828 0.105890

3.500000 0.083563 0.292470 0.106740

3.555556 0.083563 0.297113 0.107584

3.611111 0.083563 0.301755 0.108421

3.666667 0.083563 0.306397 0.117943

3.722222 0.083563 0.311040 0.329709

3.777778 0.083563 0.315682 0.678800

3.833333 0.083563 0.320324 1.123028

3.888889 0.083563 0.324967 1.645112

3.944444 0.083563 0.329609 2.234785

4.000000 0.083563 0.334252 2.885025

4.055556 0.083563 0.338894 3.511273

4.111111 0.083563 0.343536 4.654699

4.166667 0.083563 0.348179 6.134009

4.222222 0.083563 0.352821 7.883988

4.277778 0.083563 0.357464 9.865995

4.333333 0.083563 0.362106 12.05266

4.388889 0.083563 0.366748 14.42232

4.444444 0.083563 0.371391 16.95643

4.500000 0.083563 0.376033 19.63815

4.555556 0.083563 0.380675 22.45157

4.611111 0.083563 0.385318 25.38119

4.666667 0.083563 0.389960 28.41162

4.722222 0.083563 0.394603 31.52738

4.777778 0.083563 0.399245 34.71287

4.833333 0.083563 0.403887 37.95224

4.888889 0.083563 0.408530 41.22946

4.944444 0.083563 0.413172 44.52832

5.000000 0.083563 0.417815 47.83252

5.055556 0.083563 0.422457 51.12577
END FTABLE 1

END FTABLES

EXT SOURCES
<-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** 1345
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 24
<Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC
WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC
WDM 1 EVAP ENGL 1 PERLND 1 999 EXTNL PETINP
WDM 1 EVAP ENGL 1 IMPLND 1 999 EXTNL PETINP
WDM 22 IRRG ENGL 0.7 SAME PERLND 64 EXTNL SURLI
WDM 22 IRRG ENGL 0.7 SAME PERLND 61 EXTNL SURLI

END EXT SOURCES

EXT TARGETS
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 1 HYDR RO 1 1 1 WDM 1004 FLOW ENGL REPL
RCHRES 1 HYDR STAGE 1 1 1 WDM 1005 STAG ENGL REPL
COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL
COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL

END EXT TARGETS

MASS-LINK
<Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #***
MASS-LINK 2
PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL
END MASS-LINK 2
MASS-LINK 3
PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL
END MASS-LINK 3
MASS-LINK 5
IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL
END MASS-LINK 5
MASS-LINK 12
PERLND PWATER SURO 0.083333 COPY INPUT MEAN
END MASS-LINK 12
MASS-LINK 13
PERLND PWATER IFWO 0.083333 COPY INPUT MEAN
END MASS-LINK 13
MASS-LINK 15
IMPLND IWATER SURO 0.083333 COPY INPUT MEAN
END MASS-LINK 15
MASS-LINK 16

RCHRES ROFLOW COPY INPUT MEAN
END MASS-LINK 16

END MASS-LINK

END RUN
1346
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 25
Predeveloped HSPF Message File
1347
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 26
Mitigated HSPF Message File
1348
DRAFT
Aliso Viejo 1/9/2026 10:33:04 AM Page 27
Disclaimer
Legal Notice
This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2026; All Rights Reserved.

Clear Creek Solutions, Inc.
6200 Capitol Blvd. Ste F
Olympia, WA. 98501
Toll Free 1(866)943-0304
Local (360)943-0304
www.clearcreeksolutions.com
1349
Appendix I:

Pacific Park Drive Townhome Project
Noise Impact Study
1350
RK1234 // 1234-2024-01
Pacific Park Drive Townhome Project
Noise Impact Study
City of Aliso Viejo, California
May 19, 2026
1351
RK1234 // 1234-2024-01
Pacific Park Drive Townhome Project
Noise Impact Study
City of Aliso Viejo, California
Prepared for:

Mr. Peter Carlson

CARLSON STRATEGIC LAND SOLUTIONS
27134A Paseo Espada, Suite 323
San Juan Capistrano, CA 92675
Prepared by:

RK Engineering Group, Inc.
1401 Dove Street, Ste. 540
Newport Beach, CA 92660
Bryan Estrada, T.E.

Becca Morrison
Claire Stokes
W////,1////////ff/////////,1///////l//ll//////;1/#//////;1////////ff/////////ff/////////l////////////////;1/////////ff//////;1/////////////// R1< I =~~•NG rkengineer.com 1401 Dove Street I Suite 540 I Newport Beach, CA 92660 I +949.474.0809 1352
RK20938.2 // 2827-2025-02
Table of Contents
Section Page

1.0 Introduction................................................................................................................. 1-1

1.1 Purpose of Report & Study Objectives ............................................................................. 1-1

1.2 Site Location & Project Description .................................................................................. 1-1

1.3 Sensitive Receptors............................................................................................................. 1-2

1.4 Summary of Analysis Results.............................................................................................. 1-2

2.0 Fundamentals of Noise ................................................................................................ 2-1

2.1 Sound, Noise, and Acoustics ............................................................................................. 2-1

2.2 Frequency and Hertz .......................................................................................................... 2-1

2.3 Sound Pressure Levels and Decibels................................................................................ 2-1

2.4 Addition of Decibels ........................................................................................................... 2-1

2.5 Human Response to Changes in Noise Levels ................................................................ 2-1

2.6 Noise Descriptors................................................................................................................ 2-2

2.7 Sound Propagation............................................................................................................. 2-3

2.8 Vibration Descriptors.......................................................................................................... 2-5

2.9 Vibration Perception........................................................................................................... 2-5

2.10 Vibration Propagation ........................................................................................................ 2-5

2.11 Construction-Related Vibration Level Prediction ............................................................ 2-6

3.0 Regulatory Setting....................................................................................................... 3-1

3.1 State Regulations ................................................................................................................ 3-1

3.2 City of Aliso Viejo Noise Regulations................................................................................ 3-1

3.2.1 General Plan Noise Standards .............................................................................. 3-2

3.2.2 Municipal Code Noise Standards......................................................................... 3-3

4.0 Study Method and Procedures..................................................................................... 4-5

4.1 Noise Measurement Procedures and Criteria ................................................................. 4-5 ,//////////////////////////////////#///////////////////////////////////////////////////////////////////////////////////////////////////// ~ ~g/,~~~ING rkengineer.com 1353
RK20938.2 // 2827-2025-02
Table of Contents
Section Page

4.2 Stationary Noise Source Modeling ................................................................................... 4-6

4.3 Interior Noise Modeling ..................................................................................................... 4-6

4.4 Construction Noise Modeling ........................................................................................... 4-7

4.5 Construction Vibration Modeling...................................................................................... 4-8

5.0 Existing Noise Environment......................................................................................... 5-9

5.1 Noise Measurement Results .............................................................................................. 5-9

6.0 Operational Noise Impacts .......................................................................................... 6-1

6.1 Stationary Noise Source Impacts....................................................................................... 6-1

6.2 Mobile Source Noise Impacts............................................................................................ 6-3

6.2.1 Roadway Noise ....................................................................................................... 6-3

6.2.2 Airport Noise........................................................................................................... 6-3

6.3 Noise/Land Use Compatibility........................................................................................... 6-3

6.3.1 Exterior Noise/Land Use Compatibility ............................................................... 6-4

6.3.2 Interior Noise/Land Use Compatibility ................................................................ 6-5

7.0 Construction Noise and Vibration Impacts................................................................... 7-1

7.1 Typical Construction Noise Levels .................................................................................... 7-1

7.2 Construction Noise Impact Analysis ................................................................................. 7-3

7.3 Construction Vibration ....................................................................................................... 7-4 ,//////////////////////////////////#///////////////////////////////////////////////////////////////////////////////////////////////////// ~ ~g/,~~~ING rkengineer.com 1354
RK20938.2 // 2827-2025-02
List of Exhibits
Exhibit No.

Location Map ............................................................................................................................................................... A Site Plan ......................................................................................................................................................................... B Noise Monitoring Locations....................................................................................................................................... C ,//////////////////////////////////#///////////////////////////////////////////////////////////////////////////////////////////////////// ~ ~g/,~~~ING rkengineer.com 1355
RK20938.2 // 2827-2025-02
List of Tables
Table No. Page
Table 1-1 | CEQA Noise Impact Criteria ................................................................................................ 1-3 Table 2-1 | Vibration Damage Potential Threshold Criteria ................................................................ 2-6 Table 2-2 | Suggested “n” Values Based on Soil Classes..................................................................... 2-7 Table 3-1 | City of Aliso Viejo Land Use Compatibility Guidelines1.................................................... 3-2 Table 3-2 | City of Aliso Viejo General Plan Noise Standards - Residential1...................................... 3-3 Table 3-3 | City of Aliso Viejo Municipal Code Noise Standards1....................................................... 3-4 Table 4-1 | Referenced Stationary Noise Levels.................................................................................... 4-6 Table 5-1 | 24-Hour Noise Measurement Results – L-1
1 ..................................................................... 5-10 Table 5-2 | 24-Hour Noise Measurement Results – L-2
1 ..................................................................... 5-11 Table 5-3 | 24-Hour Noise Measurement Results – L-3
1 ..................................................................... 5-12 Table 6-1 | Stationary Noise Impacts – Daytime Hours ........................................................................ 6-2 Table 6-2 | Stationary Noise Impacts – Nighttime Hours...................................................................... 6-2 Table 6-3 | Exterior Noise/Land Use Compatibility (dBA CNEL)......................................................... 6-4 Table 6-4 | Future Interior Noise Levels (dBA CNEL) ........................................................................... 6-5 Table 7-1 | Typical Construction Noise Levels (dBA Leq)1................................................................... 7-2 Table 7-2 | Project Construction Noise Levels ...................................................................................... 7-3 Table 7-3 | Typical Construction Vibration Levels1............................................................................... 7-5 Table 7-4 | Construction Vibration Impact Analysis – Nearest Commercial Structure ..................... 7-6 Table 7-5 | Construction Vibration Impact Analysis – Nearest Residential Structure........................ 7-6 ,//////////////////////////////////#///////////////////////////////////////////////////////////////////////////////////////////////////// ~ ~g/,~~~ING rkengineer.com 1356
RK20938.2 // 2827-2025-02
List of Appendices
Appendix ID
City of Aliso Viejo General Plan Noise Element and Municipal Code Chapter 8.12 – Noise Control ........ A Photographs, Field Sheets, and Measured Noise Data ....................................................................................... B Stationary Noise Calculation Worksheets ............................................................................................................... C Exterior Land Use Compatibility Calculation Worksheets ................................................................................... D Construction Noise and Vibration Calculation Worksheets ................................................................................ E ,//////////////////////////////////#///////////////////////////////////////////////////////////////////////////////////////////////////// ~ ~g/,~~~ING rkengineer.com 1357
RK20938.2 // 2827-2025-02 1-1

1.0 Introduction

1.1 Purpose of Report & Study Objectives
The purpose of this report is to evaluate the potential noise impacts from the proposed Pacific Park Drive Townhome Project (hereinafter referred to as “project”) and provide recommendations, if necessary, to minimize any project noise impacts.

The assessment was conducted within the context of the California Environmental Quality Act (CEQA, California Public Resources Code Sections 21000, et seq.) and the standards and methodology follow the City of Aliso Viejo Municipal Code and General Plan requirements.

The following is provided in this report:
• A description of the study area and the proposed project; • Information regarding the fundamentals of noise;
• Identification of the regulatory setting and applicable noise standards; • Establishment of the existing ambient noise environment at the project site; • Analysis of the project’s construction and operational noise impact to adjacent receptors; • Analysis of the project’s noise/land use compatibility and preliminary interior noise levels; and

1.2 Site Location & Project Description
The proposed project site is generally located south of Pacific Park Drive, between Journey and Aliso Creek Road, in the City of Aliso Viejo. The project site is approximately 8.44 acres and is currently occupied by three (3) 2-story commercial office buildings and associated parking lots. Exhibit A shows the location map of the proposed project.

The proposed project consists of demolishing the existing commercial buildings and constructing 137 residential townhome dwelling units.

During construction, the project will demolish approximately 64,350 square feet of building area, 217,550 square feet of hardscape, and 41,200 square feet of landscaping. The project will require the import of approximately 5,700 cubic yards of earthwork material for grading purposes.

Exhibit B shows the proposed site plan used for this analysis. ,//////////////////////////////////#///////////////////////////////////////////////////////////////////////////////////////////////////// ~ ~g/,~~~ING rkengineer.com 1358
RK20938.2 // 2827-2025-02 1-2

1.3 Sensitive Receptors
Sensitive receptors are considered land uses or other types of population groups that are more sensitive to noise exposure. There are several sensitive land uses adjacent to the project site, including the following.

A project site location map, including sensitive receptor locations, is provided in Exhibit A.

Receptor-1 Existing multifamily residential land uses located to the northeast of the project site.

The nearest point of Receptor-1 (marked as circle “1” on Exhibit A) is located approximately 400 feet northeast of the northeastern corner of the project site.

Receptor-2 Existing multifamily residential land uses located to the east of the project site. The point of Receptor-2 (marked as circle “2” on Exhibit A) is located approximately 210 feet east of the project site’s eastern boundary.

Receptor-3 Existing educational land uses located to the south of the project site, including the Preschool of Aliso Viejo and the Alive Church Orange County’s daycare services. The nearest point of Receptor-3 (marked as circle “3” on Exhibit A) is located approximately 50 feet south of the project site’s southern boundary.

Receptor-4 Existing medical office land uses located to the west of the project site. The nearest point of Receptor-4 (marked as circle “4” on Exhibit A) is located approximately 80 feet west of the project site’s western boundary.

Receptor-5 Existing Orange County Fire Station 57 located to the west-northwest of the project site. The nearest point of Receptor-5 (marked as circle “5” on Exhibit A) is located directly adjacent to the project site’s western boundary.

Receptor-6 Existing multifamily residential land uses located to the northwest of the project site.

The nearest point of Receptor-6 (marked as circle “6” on Exhibit A) is located approximately 375 feet northwest of the northwestern corner of the project site.

1.4 Summary of Analysis Results
Table 1-1 provides a summary of the noise analysis results, per the CEQA impact criteria checklist. ,//////////////////////////////////#///////////////////////////////////////////////////////////////////////////////////////////////////// ~ ~g/,~~~ING rkengineer.com 1359
RK20938.2 // 2827-2025-02 1-3
Table 1-1 | CEQA Noise Impact Criteria
Noise Impact Criteria Potentially
Significant
Potentially
Significant
Unless
Mitigated
Less Than
Significant No Impact
Would the project result in:
a) Generation of a substantial temporary or
permanent increase in ambient noise levels in
the vicinity of the project in excess of standards
established in the local general plan or noise
ordinance, or applicable standards of other
agencies?
X
b) Generation of excessive groundborne vibration
or groundborne noise levels? X
c) For a project located within the vicinity of a
private airstrip or an airport land use plan or,
where such a plan has not been adopted, within
two miles of a public airport or public use airport,
would the project expose people residing or
working in the project area to excessive noise
levels?
X
,//////////////////////////////////#///////////////////////////////////////////////////////////////////////////////////////////////////// ~ ~g/,'~~~ING rkengineer.com 1360
Exhibit A Location Map 2827-2025-02 PACIFIC PARK DRIVE TOWNHOME PROJECT NOISE IMPACT STUDY // CITY OF ALISO VIEJO ENGINEERING GROUP INC. Legend N 1 = Sensitive Receptor Location = Project Site Boundary 1 4 2 3 5 6 0 /////////////////!?///////////////////!?//////////!?//////////////////////////////////////////!?/////////////////////!?///////////////////!?///////////,/////////////////////////////////////// 1361
Exhibit B Site Plan 2827-2025-02 PACIFIC PARK DRIVE TOWNHOME PROJECT NOISE IMPACT STUDY // CITY OF ALISO VIEJO ENGINEERING GROUP INC. N ///////////////// IRK I r , ,-
i-J
l ¥u
I "
..
+u,
.
,, .
-'-< 'F ol-.
,. t\_oL -I=-
~-
s:.. __ w -=- ------"""
\
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// 1362
RK20938.2 // 2827-2025-02 2-1

2.0 Fundamentals of Noise
This section of the report provides basic information about noise and presents some of the terms used within the report.

2.1 Sound, Noise, and Acoustics
Sound is a disturbance created by a moving or vibrating source and is capable of being detected by the hearing organs. Sound may be thought of as mechanical energy of a moving object transmitted by pressure waves through a medium to a human ear. For traffic, or stationary noise, the medium of concern is air. Noise is defined as sound that is loud, unpleasant, unexpected, or unwanted.

2.2 Frequency and Hertz
A continuous sound is described by its frequency (pitch) and its amplitude (loudness). Frequency relates to the number of pressure oscillations per second. Low-frequency sounds are low in pitch (bass sounding) and high-frequency sounds are high in pitch (squeak). These oscillations per second (cycles) are commonly referred to as Hertz (Hz). The human ear can hear from the bass pitch starting out at 20 Hz all the way to the high pitch of 20,000 Hz.

2.3 Sound Pressure Levels and Decibels
The amplitude of a sound determines its loudness. The loudness of sound increases or decreases, as the amplitude increases or decreases. Sound pressure amplitude is measured in units of microNewton per square inch meter (N/m2), also called micro-Pascal (µPa). One µPa is approximately one hundred billionths (0.00000000001) of normal atmospheric pressure. Sound pressure level (SPL or Lp) is used to describe in logarithmic units the ratio of actual sound pressures to a reference pressure squared. These units are called decibels and abbreviated dB.

2.4 Addition of Decibels
Because decibels are on a logarithmic scale, sound pressure levels cannot be added or subtracted by simple plus or minus addition. When two (2) sounds of equal SPL are combined, they will produce an SPL 3 dB greater than the original single SPL. In other words, sound energy must be doubled to produce a 3 dB increase. If two (2) sounds differ by approximately 10 dB the higher sound level is the predominant sound.

2.5 Human Response to Changes in Noise Levels
In general, the healthy human ear is most sensitive to sounds between 1,000 Hz and 5,000 Hz, (Aweighted scale) and it perceives a sound within that range as being more intense than a sound with a higher or lower frequency with the same magnitude. For purposes of this report as well as with most environmental documents, the A-scale weighting is typically reported in terms of A-weighted decibel (dBA). Typically, the human ear can barely perceive the change in noise level of 3 dB. A change in 5 W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1363 RK20938.2 // 2827-2025-02 2-2
dB is readily perceptible, and a change in 10 dB is perceived as being twice or half as loud . As previously discussed, a doubling of sound energy results in a 3 dB increase in sound, which means that a doubling of sound energy (e.g. doubling the volume of traffic on a highway), would result in a barely perceptible change in sound level.

2.6 Noise Descriptors
Noise in our daily environment fluctuates over time. Some noise levels occur in regular patterns, others are random. Some noise levels are constant, while others are sporadic. Noise descriptors were created to describe the different time-varying noise levels. The following are the most commonly used noise descriptors along with brief definitions.
• A-Weighted Sound Level. The sound pressure level in decibels as measured on a sound level meter using the A-weighted filter network. The A-weighting filter de-emphasizes the very low and very high frequency components of the sound in a manner similar to the response of the human ear. A numerical method of rating human judgment of loudness. • Ambient Noise Level. The composite of noise from all sources, near and far. In this context, the ambient noise level constitutes the normal or existing level of environmental noise at a given location.
• Community Noise Equivalent Level (CNEL). The average equivalent A-weighted sound level during a 24-hour day, obtained after addition of five (5) decibels to sound levels in the evening from 7:00 to 10:00 PM and after addition of ten (10) decibels to sound levels in the night before 7:00 AM and after 10:00 PM.
• Decibel (dB). A unit for measuring the amplitude of a sound, equal to 20 times the logarithm to the base 10 of the ratio of the pressure of the sound measured to the reference pressure, which is 20 micro-pascals.
• dBA. A-weighted sound level (see definition above).
• Equivalent Sound Level (Leq). The sound level corresponding to a steady noise level over a given sample period with the same amount of acoustic energy as the actual time varying noise level. The energy average noise level during the sample period. • Habitable Room. Any room meeting the requirements of the Uniform Building Code or other applicable regulations which is intended to be used for sleeping, living, cooking or dining purposes, excluding such enclosed spaces as closets, pantries, bath or toilet rooms, service rooms, connecting corridors, laundries, unfinished attics, foyers, storage spaces, cellars, utility rooms, and similar spaces.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1364 RK20938.2 // 2827-2025-02 2-3
• L(n). The A-weighted sound level exceeded during a certain percentage of the sample time. For example, L10 is the sound level exceeded 10 percent of the sample time.

Similarly, L50, L90 and L99, etc.
• Noise. Any unwanted sound or sound which is undesirable because it interferes with speech and hearing, or is intense enough to damage hearing, or is otherwise annoying.

The State Noise Control Act defines noise as "...excessive undesirable sound...". • Outdoor Living Area. Outdoor spaces that are associated with residential land uses typically used for passive recreational activities or other noise-sensitive uses. Such spaces include patio areas, barbecue areas, jacuzzi areas, etc. associated with residential uses; outdoor patient recovery or resting areas associated with hospitals, convalescent hospitals, or rest homes; outdoor areas associated with places of worship which have a significant role in services or other noise-sensitive activities; and outdoor school facilities routinely used for educational purposes which may be adversely impacted by noise. Outdoor areas usually not included in this definition are: front yard areas, driveways, greenbelts, maintenance areas and storage areas associated with residential land uses; exterior areas at hospitals that are not used for patient activities; outdoor areas associated with places of worship and principally used for short-term social gatherings; and, outdoor areas associated with school facilities that are not typically associated with educational uses prone to adverse noise impacts (for example, school play yard areas). • Percent Noise Levels. See L(n).
• Sound Level (Noise Level). The weighted sound pressure level obtained by use of a sound level meter having a standard frequency-filter for attenuating part of the sound spectrum. • Sound Level Meter. An instrument, including a microphone, an amplifier, an output meter, and frequency weighting networks for the measurement and determination of noise and sound levels.
• Single Event Noise Exposure Level (SENEL). The dBA level which, if it lasted for one (1) second, would produce the same A-weighted sound energy as the actual event.

2.7 Sound Propagation
As sound propagates from a source it spreads geometrically. Sound from a small, localized source (i.e., a point source) radiates uniformly outward as it travels away from the source in a spherical pattern.

The sound level attenuates at a rate of 6 dB per doubling of distance. The movement of vehicles down a roadway makes the source of the sound appear to propagate from a line (i.e., line source) rather than a point source. This line source results in the noise propagating from a roadway in a cylindrical spreading versus a spherical spreading that results from a point source. The sound level attenuates for a line source at a rate of 3 dB per doubling of distance.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1365 RK20938.2 // 2827-2025-02 2-4
As noise propagates from the source, it is affected by the ground and atmosphere. Noise models use hard site (reflective surfaces) and soft site (absorptive surfaces) to help calculate predicted noise levels.

Hard site conditions assume no excessive ground absorption between the noise source and the receiver. Soft site conditions such as grass, soft dirt or landscaping attenuate noise at an additional rate of 1.5 dB per doubling of distance. When added to the geometric spreading, the excess ground attenuation results in an overall noise attenuation of 3 dB per doubling of distance for a line source and 6.0 dB per doubling of distance for a point source.

Figure 1-1 | Typical Sound Levels from Indoor and Outdoor Noise Sources1 1 Source: AASHSTO. 1993. Guide on Evaluation and Abatement of Traffic Noise

COMMON OUTDOOR

NOISE LEVELS
Jet Flyover at 1000 ft.

Gos Lown Mower at 3 ft.

Diesel Truck at 50 ft.

Noise Urban Daytime
Gas Lawn Mower at 100 ft.

Commercial Area
Heavy Traffic at 300 ft.

Quiet Urban Daytime
Quiet Urban Nighttime
Quiet Suburban Nighttime
Quiet Rural Nighttime

NOISE LEVEL
(dBA)

COMMON INDOOR

NOISE LEVELS
110 Rock Bond
100 Inside Subway Train (New York)
90 80
70 60
50 40
30 20
10 0
Food Blender at 3 ft.

Garbage Disposal at 3 ft.

Shouting at 3 ft.

Vacuum Cleaner at 10 ft.

Normal Speech at 3 ft.

Large Business Office
Dishwasher Next Room
Small Theatre, Lorge Conference
Room (Background)
Library
Bedroom at Night
Concert Holl (Background)
Recording Studio
Threshold of Hearing
W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1366 RK20938.2 // 2827-2025-02 2-5

2.8 Vibration Descriptors
Ground-borne vibrations consist of rapidly fluctuating motions within the ground that have an average motion of zero. The effects of ground-borne vibrations typically only cause a nuisance to people, but at extreme vibration levels, damage to buildings may occur. Although ground-borne vibration can be felt outdoors, it is typically only an annoyance to people indoors where the associated effects of the shaking of a building can be notable. Ground-borne noise is an effect of ground-borne vibration that only exists indoors since it is produced from noise radiated from the motion of the walls and floors of a room and may also consist of the rattling of windows or dishes on shelves.

Several different methods are used to quantify vibration amplitude:
• PPV. Known as the peak particle velocity (PPV) which is the maximum instantaneous peak in vibration velocity, typically given in inches per second. • RMS. Known as the root mean squared (RMS) can be used to denote vibration amplitude. • VdB. A commonly used abbreviation to describe the vibration level (VdB) for a vibration source.

2.9 Vibration Perception
Typically, developed areas are continuously affected by vibration velocities of 50 VdB or lower. These continuous vibrations are not noticeable to humans whose threshold of perception is around 65 VdB.

Outdoor sources that may produce perceptible vibrations are usually caused by construction equipment, steel-wheeled trains, and traffic on rough roads, while smooth roads rarely produce perceptible ground-borne noise or vibration. To counter the effects of ground-borne vibration, the Federal Transit Administration (FTA) has published guidance relative to vibration impacts.

2.10 Vibration Propagation
There are three main types of vibration propagation: surface, compression, and shear waves. Surface waves, or Rayleigh waves, travel along the ground’s surface. These waves carry most of their energy along an expanding circular wavefront, similar to ripples produced by throwing a rock into a pool of water. P-waves, or compression waves, are body waves that carry their energy along an expanding spherical wavefront. The particle motion in these waves is longitudinal (i.e., in a “push-pull” fashion).

P-waves are analogous to airborne sound waves. S-waves, or shear waves, are also body waves that carry energy along an expanding spherical wavefront. However, unlike P-waves, the particle motion is transverse, or side-to-side and perpendicular to the direction of propagation.

As vibration waves propagate from a source, the vibration energy decreases in a logarithmic nature and the vibration levels typically decrease by 6 VdB per doubling of the distance from the vibration source. As stated above, this drop-off rate can vary greatly depending on the soil but has been shown W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1367 RK20938.2 // 2827-2025-02 2-6
to be effective enough for screening purposes in order to identify potential vibration impacts that may need to be studied through actual field tests.

2.11 Construction-Related Vibration Level Prediction2
Operational activities are separated into two different categories. The vibration can be transient or continuous in nature. Each category can result in varying degrees of ground vibration, depending on the equipment used on the site. Operation of equipment causes ground vibrations that spread through the ground and diminish in strength with distance. Buildings in the vicinity of the project area site respond to these vibrations with varying results ranging from no perceptible effects at the low levels to slight damage at the highest levels. The thresholds from Caltrans Transportation and Construction Vibration Guidance Manual, April 2020, in the table below provide general guidelines as to the maximum vibration limits for when vibration becomes potentially damaging to structures.

The Caltrans Transportation and Construction Vibration Guidance Manual, April 2020 provides general thresholds and guidelines as to the vibration damage potential from vibratory impacts. Table 2-1 provides general vibration damage potential thresholds.

Table 2-1 | Vibration Damage Potential Threshold Criteria Structure and Condition
PPV (in./sec.)
Transient Sources Continuous/Frequent
Intermittent Sources
Extremely fragile historic buildings, ruins,
ancient monuments

0.12 0.08
Fragile buildings 0.20 0.10
Historic and some old buildings 0.50 0.25
Older residential structures 0.50 0.30
New residential structures 1.00 0.50
Modern industrial/commercial buildings 2.00 0.50
Soil conditions have an impact on how vibration propagates through the ground. The Caltrans Transportation and Construction Vibration Guidance Manual, April 2020 provides suggested “n” values based on soil class. Table 2-2 outlines the manual’s suggested values and description. 2 Source: Caltrans Transportation and Construction Vibration Guidance Manual, April 2020.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1368 RK20938.2 // 2827-2025-02 2-7
Table 2-2 | Suggested “n” Values Based on Soil Classes
Soil Class Description of Soil Material Suggested Value of “n”
I
Weak or soft soils: loose soils, dry or partially saturated peat and muck, mud, loose beach sand, and dune sand. 1.4
II Most sands, sandy clays, silty clays, gravel, silts, and weathered rock. 1.3
III Hard soils: densely compacted sand, dry consolidated clay, consolidated glacial till, and some exposed rock. 1.1
IV Hard, component rock: bedrock, freshly exposed hard rock. 1.0 W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1369 RK20938.2 // 2827-2025-02 3-1

3.0 Regulatory Setting
The proposed project is located in the City of Aliso Viejo, and the agencies responsible for regulating noise are discussed below.

3.1 State Regulations
The State of California has established noise insulation standards as outlined in Title 24 of the Building Standards Code which in some cases requires acoustical analyses to outline exterior noise levels and to ensure interior noise levels do not exceed the interior threshold.

Noise insulation design standards for residential dwellings are established in the 2022 California Building Code, Title 24, Part 2, Volume 1, Section 1206 Sound Transmission. The City is required by the State Housing Law to adopt these State codes as minimum performance standards. The City may enact stricter noise standards throughout the city or on a case-by-case basis if deemed necessary. In brief, the Title 24 noise standards require the following for allowable interior noise levels:

1. Interior noise levels due to exterior sources must not exceed a community noise equivalent level (CNEL) or a day-night level (LDN) of 45 dBA, in any habitable room.

2. Party wall and floor-ceiling assembly designs must provide a minimum STC of 50, based on lab tests. Field tested assemblies must provide a minimum noise isolation class (NIC) of

45. 3. Floor-ceiling assembly designs must provide for a minimum impact insulation class (IIC) of 50, based on lab tests. Field tested assemblies must provide a minimum FIIC of 45.

4. Penetrations or openings in sound rated assemblies must be treated to maintain required ratings.

3.2 City of Aliso Viejo Noise Regulations
The proposed project is located in the City of Aliso Viejo and is subject to the standards and regulations established by the City of Aliso Viejo General Plan Noise Element and Municipal Code Chapter 8.12 – Noise Control, as discussed below.

A copy of the City of Aliso Viejo General Plan and Municipal Code standards are provided in Appendix A.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1370 RK20938.2 // 2827-2025-02 3-2

3.2.1 General Plan Noise Standards

3.2.1.1 Noise/Land Use Compatibility
The City of Aliso Viejo General Plan establishes planning criteria for determining a development’s noise/land use compatibility based on the community noise equivalent level (CNEL). CNEL noise levels are typically used to evaluate mobile noise source impacts such as those from roadways.

Table 3-1 shows the City of Aliso Viejo noise/land use compatibility standards for the land uses on and adjacent to the proposed project site, as prescribed in the General Plan.

Table 3-1 | City of Aliso Viejo Land Use Compatibility Guidelines1 Land Use Category
Community Noise Exposure
(dBA CNEL)2
Normally
Acceptable
Conditionally
Acceptable
Normally
Unacceptable
Clearly
Unacceptable
Residential 60 and below 60 – 70 70 – 75 75 and above
Schools, Libraries, Churches,
Hospitals, Nursing Homes 60 and below 60 – 70 70 – 80 80 and above 1 Source: City of Aliso Viejo General Plan Noise Element, Table N-2: Noise/Land Use Compatibility Matrix. 2Notes:

Normally Acceptable: Specified land use is satisfactory, based upon the assumption that any buildings involved meet conventional Title 24 construction standards. No special noise insulation requirements.

Conditionally Acceptable: New construction or development shall be undertaken only after a detailed noise analysis is made and noise reduction measures are identified and included in the project design.

Normally Unacceptable: New construction or development is discouraged. If new construction is proposed, a detailed analysis is required, noise reduction measures must be identified, and noise insulation features included in the design.

Clearly Unacceptable: New construction or development clearly should not be undertaken.

3.2.1.2 Stationary Noise Standards
In addition to the above noise/land use compatibility guidelines, the General Plan has established the following stationary noise standards. Stationary noise standards represent the maximum acceptable noise levels as measured from any residential property in the City. Accordingly, it is unlawful to cause the noise level on any residential property to exceed the exterior noise standards listed in Table 3-2:

1. For a cumulative period of more than 30 minutes in any hour;

2. Plus five (5) dBA for a cumulative period of more than 15 minutes in any hour;

3. Plus ten (10) dBA for a cumulative period of more than five (5) minutes in any hour; or

4. Plus 20 dBA for any period of time.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1371 RK20938.2 // 2827-2025-02 3-3
In addition, it is unlawful to cause the noise level on any residential property to exceed the interior noise standards listed in Table 3-2:

1. For a cumulative period of more than five (5) minutes in any hour;

2. Plus five (5) dBA for a cumulative period of more than one (1) minute in any hour; or

3. Plus ten (10) dBA for any period of time.

Table 3-2 | City of Aliso Viejo General Plan Noise Standards - Residential1 Location
Allowable Noise Level
(dBA Leq)
Daytime
(7:00 a.m. to 10:00 p.m.)
Nighttime
(10:00 p.m. to 7:00 a.m.)
Interior 55.0 45.0
Exterior 55.0 50.0
1 Source: City of Aliso Viejo General Plan Noise Element, Table N-1: Orange County Residential Noise Standards.

For the purposes of this analysis, the noise levels listed in Table 3-1 are used to evaluate the project’s noise/land use compatibility, and the noise levels listed in Table 3-2 are used to evaluate the project’s consistency with established plans, policies, and programs for noise control within the City.

It should be noted that the City’s General Plan Noise Element also places the following provisions on multifamily land uses within the City:
“The City of Aliso Viejo will continue to enforce the provisions of the California Energy Code.

Energy Code standards specify that combined indoor noise for multi-family living spaces shall not exceed 45 dBA CNEL and must be implemented when the outdoor noise level exceeds 60 dBA CNEL. The Noise Policy Map (Figure N-1) can be used to determine when and where it is appropriate to implement this standard. This standard must be applied to all new hotels, motels, and multifamily residential development.”

3.2.2 Municipal Code Noise Standards

3.2.2.1 Noise Standards
Table 3-3 shows the exterior noise standards established in Chapter 8.12 of the City of Aliso Viejo Municipal Code.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1372 RK20938.2 // 2827-2025-02 3-4
Table 3-3 | City of Aliso Viejo Municipal Code Noise Standards1 Location
Exterior Noise Level Thresholds
(dBA Leq)
Daytime
(7:00 a.m. – 10:00 p.m.)
Nighttime
(10:00 p.m. – 7:00 a.m.)
Residential – Density of less
than 10 DU/AC 50.0 45.0
Residential – Density of
10 DU/AC or more 55.0 50.0
Commercial 65.0 60.0
1 Source: City of Aliso Viejo Municipal Code Chapter 8.12 – Noise Control.

Per the Municipal Code, it is unlawful for any person at any location within the City to create any noise, or to allow the creation of any noise on property owned, leased, occupied, or otherwise controlled by the person, when the foregoing causes the noise level, when measured on any other parcel, to exceed:

1. The noise standard for a cumulative period of more than 30 minutes in any hour;

2. The noise standard plus five (5) dBA for a cumulative period of more than 15 minutes in any hour;

3. The noise standard plus ten (10) dBA for a cumulative period of more than five (5) minutes in any hour;

4. The noise standard plus 15 dBA for a cumulative period of more than one (1) minute in any hour; or

5. The noise standard plus 20 dBA for any period of time.

3.2.2.2 Construction Noise Standards
Per the Municipal Code, noise sources associated with construction, repair, remodeling, or grading of any real property shall be exempted from the provisions of Chapter 8.12, provided said activities do not take place between the hours of eight p.m. and seven a.m. on weekdays, eight p.m. and eight a.m. on Saturday, or at any time on Sunday or a federal holiday.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1373 RK20938.2 // 2827-2025-02 4-5

4.0 Study Method and Procedures
The following section describes the noise measurement procedures and locations, noise modeling procedures, and assumptions used in this analysis.

4.1 Noise Measurement Procedures and Criteria
Noise measurements are taken to determine the existing noise levels. A noise receiver or receptor is any location in the noise analysis in which noise might produce an impact. The following criteria are used to select measurement locations and receptors:
• Locations expected to receive the highest noise impacts, such as the nearest houses to the project site;
• Locations that are acoustically representative and equivalent to the area of concern; • Human land usage; and
• Sites clear of major obstructions and contamination.

RK conducted the sound level measurements in accordance with Caltrans technical noise specifications. All measurement equipment meets American National Standards Institute (ANSI) specifications for sound level meters (ANSI S1.4: Specification for Sound Level Meter, 1983).

Piccolo-II Type 2 integrating-averaging level meters were used to conduct noise measurements at the project site and property boundaries.

The Leq, Lmin, Lmax, L2, L8, L25, and L50 statistical data were recorded over the measurement time intervals and the information was utilized to define the noise characteristics for the project. The following gives a brief description of the procedures for sound level measurements:
• Microphones for sound level meters were placed five (5) feet above the ground; • Sound level meters were calibrated before each measurement; • Following the calibration of equipment, a windscreen was placed over the microphone; • Frequency weighting was set on “A” and slow response; and • Temperature and sky conditions were observed and documented.

Appendix B includes photographs, field sheets, and measured noise data. '1//////////////////////////kW////////////////////////////////////////////////////////////////////////////////////////////////////////// ~ ~:;"g~~- rkenglneer.com 1374
RK20938.2 // 2827-2025-02 4-6

4.2 Stationary Noise Source Modeling
Stationary noise generated by the project was modeled using a computer program that replicates the FHWA Noise Prediction Model (FHWA-RD-77-108). The FHWA model arrives at a predicted noise level through a series of adjustments to the reference energy noise level. For stationary sources, the following noise levels were applied to the model. The model outputs the projected noise level based on the following key parameters:
• Referenced noise level (i.e., how loud a source is at a specific distance); • Vertical and horizontal distances of sensitive receptor from the noise source; • Vertical and horizontal distances of noise barriers from the noise source and receptor; • Typical noise source spectra; and
• Topography.

The primary source of onsite noise generated by the proposed project would be the operation of HVAC equipment. Potential HVAC/condenser equipment noise is modeled assuming that equipment would be located at ground level and shielded behind noise barrier walls/enclosures. It is assumed that the project will include one HVAC unit per townhouse dwelling unit. To be conservative, noise impacts are modeled based on the simultaneous operation of five (5) HVAC units.

To model HVAC noise, reference noise levels for typical residential HVAC units are used. Table 4-1 indicates the referenced noise levels used in this analysis.

Table 4-1 | Referenced Stationary Noise Levels
Noise Source Distance from Source
(Feet)
Noise Levels
(dBA Leq and Lmax)
HVAC1 3.28 65.0
1Noise level is representative of a single unit.

4.3 Interior Noise Modeling
The interior noise level is the difference between the projected exterior noise level at the structure’s façade and the noise reduction provided by the structure itself. Typical building construction will provide a conservative 12 dBA noise level reduction with a “windows open” condition and a very conservative 20 dBA noise level reduction with “windows closed”. The interior noise level is estimated by subtracting the building shell design from the estimated exterior noise level. '1//////////////////////////kW////////////////////////////////////////////////////////////////////////////////////////////////////////// ~ ~:;"g~~- rkenglneer.com 1375
RK20938.2 // 2827-2025-02 4-7
The interior noise analysis is based on industry standards for building noise reduction established by the Federal Highway Administration (FHWA), the 2013 Caltrans Technical Noise Supplement to the Traffic Noise Analysis Protocol (TeNS), the California Office of Noise Control Catalog of STC and IIC Ratings for Wall and Floor/Ceiling Assemblies, and the California Building Standards Code, Title 24.

The TeNS manual shows that the noise reduction due to building exteriors with ordinary sash windows (windows closed) is at least 20 decibels. By providing upgraded STC rated windows, the project design is considered adequate to meet interior noise standards. The building’s exterior walls will be constructed per the latest building code insulation requirements and provide occupants with the most protection from exterior noise. Insulated exterior walls, designed per the latest California Building Standards, would provide a minimum of STC 35-40. Windows, on the other hand, are one of the acoustically weakest parts of the structure. Therefore, for a conservative estimate of preliminary interior noise, the building’s noise reduction potential is limited to the STC of the windows.

4.4 Construction Noise Modeling
The construction noise vibration assessment is based on the General Assessment methodology set forth by the FTA’s Transit Noise and Vibration Impact Assessment Manual, Section 7 – Noise and Vibration during Construction. This analysis utilizes the Federal Highway Administration (FHWA) Roadway Construction Noise Model, together with several key construction parameters, to estimate future construction noise levels during each phase of construction. Consistent with the FTA General Assessment methodology, the following assumptions have been utilized in the construction noise model:
• Noise emission level (Lemission) – Determine the emission level at 50 feet according to noise from typical construction equipment.
• Usage factor (AdjUsage) – Assume a usage factor of one (1). This assumes a time period of one-hour with full power operation.
• Distance (D) – Assume that all equipment operates at the center of the project, or centerline for guideway or highway construction projects.
• Ground effect (G) – G equals zero (0) assuming free-field conditions and ignoring ground effects.
• The Leq.equip is determined only for the two noisiest pieces of equipment expected to be used in each phase of construction. The equipment noise levels are summed for each phase of construction using decibel addition.

Noise levels were projected from the center of the project site to the adjacent sensitive receptor property lines. Although some construction activity may occur closer to the adjacent receptors than the center of the project site, noise levels are based on an average distance from the center of the site per FTA General Assessment recommendations.
'1//////////////////////////kW////////////////////////////////////////////////////////////////////////////////////////////////////////// ~ ~:;"g~~- rkenglneer.com 1376
RK20938.2 // 2827-2025-02 4-8

4.5 Construction Vibration Modeling
The construction vibration assessment is based on the methodology set forth within the Caltrans Transportation and Construction Induced Vibration Guidance Manual. The vibration impacts from bulldozers, heavy truck loading, vibratory rollers and compactors, and caisson drilling activity are analyzed. All vibratory activity is analyzed as a continuous and/or frequent event and is required to comply with the applicable guidance threshold criteria. It is expected that vibration levels will be highest during the paving phase. No impact pile driving is expected as part of this project.

Vibratory impacts were calculated from the nearest expected location of on-site construction to the nearest sensitive receptors and structures using the reference vibration levels, soil conditions, and the reference equation PPV= PPV ref (25/D)^n (in/sec) (from Caltrans Manual) where:
• PPV = reference measurement at 25 feet from the vibration source; • D = distance from equipment to property line; and
• n = vibration attenuation rate through ground (n = 1.1 was utilized for this study). '1//////////////////////////kW////////////////////////////////////////////////////////////////////////////////////////////////////////// ~ ~:;"g~~- rkenglneer.com 1377
RK20938.2 // 2827-2025-02
5-9

5.0 Existing Noise Environment
The existing noise environment for the project site and surrounding areas has been established based on noise measurement data collected by RK. The project setting is residential and commercial, and the primary sources of environmental noise impacting the project site are commercial activity at adjacent properties, fire station activity, and roadway activity along Aliso Viejo Parkway and Pacific Park Drive.

5.1 Noise Measurement Results
To determine the existing noise level environment, RK conducted three (3) 24-hour noise measurements at the project site and receptors.

Noise levels were measured on August 7, 2025, using Piccolo-II Type 2 integrating-averaging sound level meters. The information was utilized to establish the noise characteristics of the existing ambient environment.

The noise monitoring locations were selected based on the proximity and location of adjacent sensitive receptors. Exhibit C graphically illustrates the location of the noise measurements. • Noise Monitoring Location 1 (L-1) was taken near the northern boundary of the project site, approximately 155 feet south of the centerline of Pacific Park Drive. • Noise Monitoring Location 2 (L-2) was taken near the eastern boundary of the project site, approximately 150 feet west of the centerline of Aliso Creek Road. • Noise Monitoring Location 3 (L-3) was taken near the western boundary of the project site, approximately 155 feet east of the centerline of Journey.

Noise measurements were conducted at the above-selected locations to determine the existing ambient noise environment at the project site and nearby sensitive receptors.

Results of the ambient noise measurements are shown in Tables 5-1, 5-2 and 5-3. Appendix B includes photographs, field sheets, and measured noise data.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1378 RK20938.2 // 2827-2025-02
5-10
Table 5-1 | 24-Hour Noise Measurement Results – L-1
1 Time dBA Leq Time dBA Leq
12:00 AM 51.6 12:00 PM 61.6
1:00 AM 49.1 1:00 PM 55.8
2:00 AM 62.9 2:00 PM 56.5
3:00 AM 47.7 3:00 PM 59.0
4:00 AM 51.1 4:00 PM 61.1
5:00 AM 54.5 5:00 PM 59.1
6:00 AM 56.9 6:00 PM 57.0
7:00 AM 58.4 7:00 PM 63.0
8:00 AM 62.1 8:00 PM 58.3
9:00 AM 59.6 9:00 PM 56.3
10:00 AM 57.3 10:00 PM 55.3
11:00 AM 57.4 11:00 PM 58.1
24-Hour CNEL 64.0
1 L-1 was measured on August 7, 2025.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1379 RK20938.2 // 2827-2025-02
5-11
Table 5-2 | 24-Hour Noise Measurement Results – L-2
1 Time dBA Leq Time dBA Leq
12:00 AM 53.0 12:00 PM 62.7
1:00 AM 52.1 1:00 PM 61.9
2:00 AM 52.4 2:00 PM 61.9
3:00 AM 53.8 3:00 PM 61.3
4:00 AM 54.9 4:00 PM 61.6
5:00 AM 57.5 5:00 PM 62.0
6:00 AM 61.6 6:00 PM 62.9
7:00 AM 63.0 7:00 PM 61.3
8:00 AM 63.7 8:00 PM 60.5
9:00 AM 64.1 9:00 PM 60.1
10:00 AM 62.4 10:00 PM 60.0
11:00 AM 62.5 11:00 PM 61.4
24-Hour CNEL 65.6
1 L-2 was measured on August 7, 2025.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1380 RK20938.2 // 2827-2025-02
5-12
Table 5-3 | 24-Hour Noise Measurement Results – L-3
1 Time dBA Leq Time dBA Leq
12:00 AM 45.4 12:00 PM 51.2
1:00 AM 45.3 1:00 PM 51.7
2:00 AM 56.1 2:00 PM 51.8
3:00 AM 44.4 3:00 PM 51.9
4:00 AM 44.9 4:00 PM 55.4
5:00 AM 51.3 5:00 PM 53.5
6:00 AM 52.4 6:00 PM 49.7
7:00 AM 55.8 7:00 PM 50.0
8:00 AM 52.4 8:00 PM 47.6
9:00 AM 54.1 9:00 PM 47.7
10:00 AM 51.8 10:00 PM 47.7
11:00 AM 49.6 11:00 PM 47.3
24-Hour CNEL 57.2
1 L-3 was measured on August 7, 2025.

As shown in Table 5-1, Table 5-2 and Table 5-3, the existing ambient noise levels at the proposed project site range from approximately 57.2 dBA CNEL to 65.6 dBA CNEL.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1381 Exhibit C Noise Monitoring Locations 2827-2025-02 PACIFIC PARK DRIVE TOWNHOME PROJECT NOISE IMPACT STUDY // CITY OF ALISO VIEJO ENGINEERING GROUP INC. Legend N 1 = Noise Monitoring Location = Project Site Boundary 3 1 2 0 /////////////////!?///////////////////!?//////////!?//////////////////////////////////////////!?/////////////////////!?///////////////////!?///////////,/////////////////////////////////////// 1382
RK20938.2 // 2827-2025-02 6-1

6.0 Operational Noise Impacts
The following noise impact analysis has been performed to determine whether the proposed project would result in a substantial increase in ambient noise levels in the vicinity of the site. Additionally, the noise analysis examines whether the project can meet the City of Aliso Viejo and State of California requirements for residential exterior and interior noise exposure.

6.1 Stationary Noise Source Impacts
The proposed project consists of constructing and operating 137 single-family attached dwelling units. The primary sources of potential on-site noise would be HVAC equipment and other general residential activity.

These types of on-site stationary noises would not typically be categorized as loud, unnecessary, or unusual noise that disturbs the peace or quiet of any neighborhood, or that causes discomfort or annoyance to any person of normal sensitiveness. In particular, social activities and vehicle-related noise are generally substantially less during the noise sensitive nighttime hours.

To help ensure onsite noise levels do not exceed the City of Aliso Viejo General Plan and Municipal Code noise standards, the following stationary noise impact analysis has been prepared. The analysis assumes that onsite HVAC units will be operating continuously during daytime hours (7:00 a.m. to 10:00 p.m.) and nighttime hours (10:00 p.m. to 7:00 a.m.). The result is a worst-case assessment of impacts, as HVAC units would likely only operate intermittently throughout the day.

The referenced noise level used for this analysis is indicative of the noise level generated by a typical HVAC unit at the noise source location. Onsite HVAC noise is modeled assuming that equipment would be located at ground level and shielded behind noise barrier walls/enclosures.

The closest potential daytime HVAC location to the adjacent residential receptors will be near the southern boundary of the project site, approximately 70 feet from Receptor-3, which consists of educational land uses. Although the City of Aliso Viejo Municipal Code does not include stationary noise thresholds for educational buildings, these land uses are considered sensitive for the purposes of this analysis. Therefore, potential noise impacts are conservatively estimated at a distance of 70 feet from the nearest potential HVAC location and are compared with the City’s stationary noise thresholds for residential land uses. It is assumed that the educational land uses located at Receptor-3 are only occupied and operational during daytime hours. Therefore, this analysis compares the worst-case noise levels at Receptor-3 to the City’s daytime noise level threshold only.

Potential noise level impacts during nighttime hours are assessed at the property line of Receptor-5, which is the nearest adjacent receptor that is assumed to be occupied and operational during nighttime hours. Receptor-5 is located approximately 125 feet from the nearest potential onsite HVAC location.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1383 RK20938.2 // 2827-2025-02 6-2
To estimate noise level impacts at the adjacent receptors, the referenced noise level is input into the FHWA model and projected from the nearest potential HVAC locations to the nearest receptor property lines, at a distance of approximately 70 feet from Receptor-3, and 125 feet from Receptor-5.

The model projections take into account the noise attenuation effects from distance, local topography, and ground effects. In addition, potential HVAC/condenser equipment noise is modeled assuming that the equipment would be located at ground level and shielded behind noise barrier walls/enclosures.

Table 6-1 shows the projected noise levels during daytime hours at the nearest adjacent residential receptors. Table 6-2 shows the projected noise levels during nighttime hours at the nearest adjacent residential receptors. Stationary noise calculation worksheets are provided in Appendix C.

Table 6-1 | Stationary Noise Impacts – Daytime Hours
Noise Source
Receptor Distance from
Noise Source
(feet)
Noise Level at Receptor (dBA Leq)
Daytime
(Leq / Lmax
7 a.m. – 10 p.m.)
HVAC1 70.0 37.8 / 37.8
Noise Level Threshold 55.0 / 75.0
Noise Level Exceeds Threshold? No / No
1Noise level is indicative of five (5) units.

Table 6-2 | Stationary Noise Impacts – Nighttime Hours
Noise Source
Receptor Distance from
Noise Source
(feet)
Noise Level at Receptor (dBA Leq)
Nighttime
(Leq / Lmax
10 p.m. – 7 a.m.)
HVAC1 125.0 32.8 / 32.8
Noise Level Threshold 50.0 / 70.0
Noise Level Exceeds Threshold? No / No
1Noise level is indicative of five (5) units.

As shown in the tables above, noise levels generated by the project are not expected to exceed the City’s daytime or nighttime noise standards at any of the adjacent sensitive receptor locations.

As a result, the project will not generate stationary noise levels in excess of the noise standards established by the City, and the impact is considered less than significant.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1384 RK20938.2 // 2827-2025-02 6-3

6.2 Mobile Source Noise Impacts

6.2.1 Roadway Noise
The project is not expected to cause a substantial increase in ambient noise levels in the vicinity of the site as a result of increased traffic volumes along adjacent roadways. Typically, it takes a doubling of traffic volume along a roadway to cause a significant increase in ambient noise levels of more than 3 dBA.

The main source of roadway noise affecting the proposed project site and adjacent receptors is activity along Pacific Park Drive and Aliso Creek Road. Annual average daily traffic (AADT) along these roadways were obtained from Streetlight, an online transportation analytics platform that derives traffic data from location-based services and GPS sources. Streetlight provides validated AADT estimates for roadway segments, which can be used in environmental analyses to establish existing, baseline conditions.

Per 2024 Streetlight data, the segments of Pacific Park Drive adjacent to the proposed project site have an existing annual average daily traffic (AADT) of approximately 16,074 vehicles. The segment of Aliso Creek Road adjacent to the proposed project site has an existing annual average daily traffic (AADT) of approximately 16,664 vehicles.

Based on the ITE Trip Generation Manual, 11th Edition trip generation rates for Land Use 215: SingleFamily Attached Housing, the proposed project is forecast to generate approximately 986 daily trips.

Hence, the amount of traffic generated by the project will not double the amount of traffic along Pacific Park Drive or Aliso Creek Road, either directly or cumulatively, and therefore the increase in roadway noise levels as a result of the project will be less than significant.

6.2.2 Airport Noise
John Wayne Airport, located in Santa Ana, California, is the nearest airport to the proposed project site at a distance of approximately 10 miles. The project site is not located within the John Wayne Airport, or any other airport’s, area of influence.

Furthermore, as described above, the proposed project is not expected to expose people residing or working in the project area to excessive noise levels. Therefore, the project will have no impact on airport-adjacent land uses.

6.3 Noise/Land Use Compatibility
The project proposes to site new single-family attached dwelling units located near the southwest corner of Pacific Park Drive and Aliso Creek Road. Traffic noise from these roadways will be the primary source of noise impacting the project site and may expose future residents to noise levels above the City of Aliso Viejo exterior noise thresholds for residential uses.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1385 RK20938.2 // 2827-2025-02 6-4

6.3.1 Exterior Noise/Land Use Compatibility
A noise/land use compatibility assessment has been prepared to help determine whether existing exterior noise levels affecting the project site exceed the City’s noise/land use compatibility threshold for residential land uses. Exterior ambient noise levels are assessed at the first-row residential building façades of each dwelling unit facing Pacific Park Drive and Aliso Creek Road.

Future exterior noise levels are estimated based on the existing ambient noise level measurements collected by RK. The measured noise levels were adjusted to reflect the minimum distance from adjacent roadways to the nearest project building façades. To account for future increases in roadway volumes, a three-decibel increase has been applied to the measured noise levels. This is a conservative estimate, as a doubling of traffic volume along a roadway would be required to increase ambient noise levels by 3 dBA or more3.

Table 6-3 shows the anticipated exterior noise levels at the first-row residential building façades.

Future exterior noise calculation worksheets are provided in Appendix D.

Table 6-3 | Exterior Noise/Land Use Compatibility (dBA CNEL) Receptor Location Noise Monitoring Location Estimated Future Exterior Noise Levels
First-row building façades facing
Pacific Park Dr. L-1 72.5
First-row building façades facing
Aliso Creek Rd. L-2 72.1
As shown in Table 6-3, future exterior ambient noise levels are expected to range from approximately

72.1 dBA CNEL to 72.5 dBA CNEL and fall within the Normally Unacceptable noise/land use compatibility category.

Per the City of Aliso Viejo General Plan, new construction or development of Normally Unacceptable land uses requires a detailed noise analysis, identification of noise reduction measures, and noise insulation features included in the design.

In order to ensure that interior noise levels comply with County and State standards, the following preliminary interior noise analysis is provided.
3 Source: Technical Noise Supplement to the Traffic Noise Analysis Protocol, California Department of Transportation (Caltrans), September 2013.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1386 RK20938.2 // 2827-2025-02 6-5

6.3.2 Interior Noise/Land Use Compatibility
The project must show that interior noise levels at the project site will not exceed the City of Aliso Viejo and State of California noise/land use compatibility threshold for residential land uses. A preliminary interior noise analysis has been performed for the first row of habitable dwellings facing the adjacent roadways using a typical “windows open” and “windows closed” condition. A “windows open” condition assumes 12 dBA of noise attenuation from the exterior noise level. A “windows closed” condition” assumes 20 dBA of noise attenuation from the exterior noise level.

Table 6-4 indicates the future interior noise levels along the adjacent roadways.

Table 6-4 | Future Interior Noise Levels (dBA CNEL)
Exterior Façade
Study Location
Projected
Exterior
Noise
Level1
Interior
Noise
Standard
Required
Building Shell
Noise
Reduction
Interior Noise Level
with Standard Windows
(STC ~ 25) Required
STC Rating “Windows
Open”2
“Windows
Closed”3
First-row dwelling units
facing Pacific Park Dr. 72.5

45.0 27.5 60.5 52.5 33
First-row dwelling units
facing Aliso Creek Rd. 72.1 27.1 60.1 52.1 33
1Worst-case future exterior noise levels are based on existing ambient noise level measurements collected by RK. 2 A minimum of 12 dBA noise reduction is assumed with the “windows open” condition. 3 A minimum of 20 dBA noise reduction is assumed with the “windows closed" condition.

The project is expected to require a “windows closed” condition and upgraded STC-rated windows for all residential units facing adjacent roadways. To accommodate windows closed conditions, all residential units facing the adjacent roadways shall be equipped with adequate fresh air ventilation.

Exterior walls, designed per the latest California Building Standards are typically rated between STC 35-40. In order to ensure adequate noise attenuation is provided from the building shell, exterior walls should be designed to meet the required sound attenuation targets. Attic vents and other openings should be baffled and oriented away from facing the adjacent roadways.

Prior to issuance of building permits, the project proponent should demonstrate to the City Building Department that the proposed building shell and window assemblies will achieve exterior to interior noise reduction necessary to meet the State of California and City of Aliso Viejo requirements.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1387 RK20938.2 // 2827-2025-02 7-1

7.0 Construction Noise and Vibration Impacts
Temporary construction noise and vibration impacts have been assessed from the project site to the surrounding adjacent land uses. The degree of construction noise and vibration will vary depending on the type of construction activity taking place and the location of the activity relative to the surrounding properties.

During the construction period, the contractors will be required to comply with the City of Aliso Viejo Municipal Code Chapter 8.12. Per the Municipal Code, noise sources associated with construction, repair, remodeling, or grading of any real property shall be exempted from the provisions of Chapter

8.12, provided said activities do not take place between the hours of eight p.m. and seven a.m. on weekdays, eight p.m. and eight a.m. on Saturday, or at any time on Sunday or a federal holiday. The Municipal Code does not include specific noise level limits for construction activities.

Because the City of Aliso Viejo does not establish quantitative thresholds for construction-related noise, the proposed project’s potential construction noise impacts have been evaluated using the Federal Transit Administration (FTA) Transit Noise and Vibration Impact Assessment (2006) criteria.

The FTA provides criteria for assessing construction noise impacts based on the potential for adverse community reaction. For residential uses, the daytime noise threshold is 90 dBA Leq for a 1-hour period. It is assumed that no project-related construction would occur during the noise-sensitive nighttime hours.

Construction phasing and equipment usage assumptions are referenced from the Pacific Park Drive Townhome Project Air Quality, Greenhouse Gas, and Energy Study, City of Aliso Viejo, prepared by RK.

7.1 Typical Construction Noise Levels
Table 7-1 shows typical construction noise levels compiled by the Environmental Protection Agency (EPA) for common-type construction equipment. Typical construction noise levels are used to estimate potential project construction noise levels at the adjacent sensitive receptors.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1388 RK20938.2 // 2827-2025-02 7-2
Table 7-1 | Typical Construction Noise Levels (dBA Leq)1 Equipment Type Noise Level at 50 Feet
Earth Moving
Compactors (Rollers) 73 - 76
Front Loaders 73 - 84
Backhoes 73 - 92
Tractors 75 - 95
Scrapers, Graders 78 - 92
Pavers 85 - 87
Trucks 81 - 94
Materials Handling
Concrete Mixers 72 - 87
Concrete Pumps 81 - 83
Cranes (Movable) 72 - 86
Cranes (Derrick) 85 - 87
Stationary
Pumps 68 - 71
Generators 71 - 83
Compressors 75 - 86
Impact Equipment
Pneumatic Wrenches 82 - 87
Jack Hammers, Rock Drills 80 - 99
Pile Drivers (Peak) 95-105
Other
Vibrators 68 - 82
Saws 71 - 82
1 Referenced noise levels from the Environmental Protection Agency (EPA).

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1389 RK20938.2 // 2827-2025-02 7-3

7.2 Construction Noise Impact Analysis
This assessment analyzes potential noise impacts of the two noisiest pieces of equipment during all expected phases of construction, including demolition, site preparation, grading, building construction, paving, and architectural coating. Noise levels are calculated based on an average distance of equipment over a 1-hour period to the nearest adjacent residential receptors. The project’s estimated construction noise levels have been calculated using the Federal Highway Administration Roadway Construction Noise Model Version 1.1.

Table 7-2 shows the noise level impacts from the center of the project site to the nearest receptor property line at Receptor-5. Construction noise calculation worksheets are provided in Appendix E.

Table 7-2 | Project Construction Noise Levels
Phase Equipment Quantity
Equipment
Noise Level at
250 ft.
(dBA Leq)
Combined
Noise Level
(dBA Leq)
Demolition
Concrete/Industrial Saws 1 75.6

76.3 Rubber Tired Dozers 1 67.7
Site Preparation Tractors/Loaders/Backhoes 2 70.0 73.0
Grading
Graders 1 71.0

73.6 Tractors/Loaders/Backhoes 1 70.0
Building Construction Tractors/Loaders/Backhoes 2 70.0 73.0 Paving Rollers 2 66.0 69.0
Architectural Coating Air Compressors 1 63.7 63.7
Worst-Case Construction Phase Noise Level (dBA Leq) 76.3 FTA Daytime General Assessment Construction Noise Criteria (dBA Leq)1 90.0 Noise level exceeds criteria? No
1 Source: Federal Transit Administration (FTA). Transit Noise and Vibration Impact Assessment Manual, Section 7: Noise and Vibration During Construction.

As shown in Table 7-2, the project is not expected to generate noise levels which exceed the FTA General Assessment construction noise threshold for residential land uses. As a result, the project impact is considered less than significant.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1390 RK20938.2 // 2827-2025-02 7-4

7.3 Construction Vibration
To determine the vibratory impacts during construction, reference construction equipment vibration levels were utilized and then extrapolated to the façade of the nearest adjacent structures.

The nearest structure to the project site is the existing gas station located to the east of the proposed project site. This structure is considered a “modern industrial/commercial building” and is located approximately 30 feet from the nearest expected area of onsite construction activity.

The nearest residential structures to the project site are the existing homes located to the east of the proposed project site. These structures are considered “new residential homes” are located approximately 215 feet from the nearest expected areas of onsite construction activity.

The construction of the proposed project is not expected to require the use of substantial vibrationinducing equipment or activities, such as pile drivers or blasting. The main source of vibration impacts during the construction of the project would be the operation of equipment such as bulldozer activity during site preparation and loading trucks during grading and excavation.

The construction vibration assessment utilizes the referenced vibration levels and methodology set forth within the Transit Noise and Vibration Impact Assessment Manual, Federal Transit Administration, September 2018. Table 7-3 shows the FTA-referenced vibration levels.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1391 RK20938.2 // 2827-2025-02 7-5
Table 7-3 | Typical Construction Vibration Levels1
Equipment
Peak Particle Velocity (PPV) at
25 Feet
(in./sec.)
Approximate Vibration Level
(LV) at 25 feet
Piledriver (impact)

1.518 (upper range) 112

0.644 (typical) 104
Piledriver (sonic)

0.734 upper range 105

0.170 typical 93
Clam shovel drop (slurry wall) 0.202 94
Hydromill 0.008 in soil 66
(slurry wall) 0.017 in rock 75
Vibratory Roller 0.210 94
Hoe Ram 0.089 87
Large bulldozer 0.089 87
Caisson drill 0.089 87
Loaded trucks 0.076 86
Jackhammer 0.035 79
Small bulldozer 0.003 58
1 Source: Federal Transit Administration (FTA). Transit Noise and Vibration Impact Assessment Manual, Section 7: Noise and Vibration During Construction.

Table 7-4 shows the project’s construction-related vibration analysis at the nearest commercial structure to the project construction area. Table 7-5 shows the project’s construction-related vibration analysis at the nearest residential structure to the project’s construction area. Construction vibration calculation worksheets are provided in Appendix E.

W/////////////////////////////////////////////////,7//////////////////////////////////////////////////////////////////////////////////// ~ ~~~~NG rkengineer.com 1392 RK20938.2 // 2827-2025-02 7-6
Table 7-4 | Construction Vibration Impact Analysis – Nearest Commercial Structure
Construction Activity
Distance to Nearest
Structure
(Feet)
Duration
Calculated Vibration
Level (PPV)
(in./sec.)
Large Bulldozer
30 Continuous/Frequent 0.073
Loaded Trucks Continuous/Frequent 0.062
Vibratory Rollers Continuous/Frequent 0.172
Worst-Case Construction Vibration Level 0.172
Vibration Damage Potential Threshold1 0.500
Vibration level exceeds threshold? No
1 Source: Caltrans Transportation and Construction Vibration Guidance Manual (April 2020) vibration damage potential threshold for “new residential structures”.

Table 7-5 | Construction Vibration Impact Analysis – Nearest Residential Structure
Construction Activity
Distance to Nearest
Structure
(Feet)
Duration
Calculated Vibration
Level (PPV)
(in./sec.)
Large Bulldozer
215
Continuous/Frequent 0.008
Loaded Trucks Continuous/Frequent 0.007
Vibratory Rollers Continuous/Frequent 0.020
Worst-Case Construction Vibration Level 0.020
Vibration Damage Potential Threshold1 0.500
Vibration level exceeds threshold? No
1 Source: Caltrans Transportation and Construction Vibration Guidance Manual (April 2020) vibration damage potential threshold for “new residential structures”.

Based on the tables above, project-related construction activity is not expected to cause any potential damage to the nearest structures. Hence, the impact from construction-related vibration will be less than significant.

NOISE ELEMENT

ALISO VIEJO GENERAL P LAN
N-1

INTRODUCTION
The City of Aliso Viejo desires to achieve and maintain an environment free from objectionable, excessive, or harmful noise to protect and enhance quality of life for residents. In addition to causing irritation, high noise levels can be a source of stress for those working and residing nearby. Creating effective strategies that reduce excessive noise and limit the community’s exposure to loud noise sources is the central objective of the General Plan Noise Element.

PURPOSE OF THE NOISE ELEMENT
The purpose of the Noise Element is to identify current and potential future sources of noise so that future land uses can be organized and new development adequately designed in a manner that minimizes noise impacts to community residents and businesses. This Element contains policies and programs to achieve and maintain a safe noise environment within Aliso Viejo.

SCOPE AND CONTENT OF THE NOISE ELEMENT
The Noise Element is a mandatory component of the General Plan as outlined in the State Government Code. Noise exposure contours in the Element present quantified projections of future noise conditions associated with both short- and long-term growth. This noise information serves as the basis for guidelines describing compatible land uses.

The Noise Element has three sections: 1) this Introduction; 2) Issues, Goals and Policies; and 3) the Noise Plan. In the second section (Issues, Goals and Policies), goals and policies are established which address identified noise issues. The goals identify overall City desires and consist of broad statements of purpose and direction. The policies are guidelines aimed to reduce or avoid adverse noise effects on residents and businesses. The Noise Plan describes how goals and policies will be achieved, or implemented. Specific implementation for the Noise Element is provided in the General Plan Implementation Program, located in Appendix A.

RELATED PLANS AND PROGRAMS
Many plans and programs enacted through State and local legislation directly relate to the Noise Element.

These plans and programs are administered by agencies with powers to enforce State and local laws.

California Environmental Quality Act (CEQA) and Guidelines The California Environmental Quality Act (CEQA) was adopted by the State legislature in response to a public mandate for thorough environmental analysis of projects that might affect the environment. The provisions of the law and environmental review procedure are described in the CEQA Statutes and the CEQA Guidelines. Excessive noise is considered an environmental impact under CEQA. Implementation of G NERALPI.AN
1396

NOISE ELEMENT

ALISO VIEJO GENERAL P LAN
N-2
CEQA ensures that during the decision making stage of development, City officials and the general public will be able to assess the potential noise impacts associated with private and public development projects.

California Noise Insulation Standards (Title 24)
The California Commission of Housing and Community Development officially adopted noise insulation standards in 1974. In 1988, the Building Standards Commission approved revisions to the standards (Title 24, Part 2, California Code of Regulations). As revised, Title 24 establishes an interior noise standard of 45 dB(A) for residential space (CNEL or Ldn). Acoustical studies must be prepared for residential structures to be located within noise contours of 60 dB(A) or greater (CNEL or Ldn) from freeways, major streets, thoroughfares, rail lines, rapid transit lines, or industrial noise sources. The studies must demonstrate that the building is designed to reduce interior noise to 45 dB(A) or lower (CNEL or Ldn).

City of Aliso Viejo Noise Control Ordinance
Upon incorporation, Aliso Viejo adopted the Orange County Noise Control Ordinance. The Ordinance establishes interior and exterior noise standards, controls for nuisance and business-related noise, and specific standards for acceptable daytime and nighttime noise levels. Requirements of the Noise Control Ordinance are identified in this Element.

RELATIONSHIP TO OTHER GENERAL PLAN ELEMENTS
State planning law requires the Noise Element to be consistent with other General Plan elements. The Land Use, Circulation and Conservation/Open Space Elements are most closely related to the Noise Element.

Policies and plans developed in the Noise Element are intended to protect current and planned land uses identified in the Land Use Element from excessive noise. Potential noise sources are identified in the Noise Element and programs are established to avoid or mitigate noise impacts from planned development. At the same time, policies contained in the Land Use Element ensure that environmental conditions, including noise, are considered in all land use decisions. Preventing the intrusion of negative environmental conditions, such as excessive noise, in order to create a healthy environment is a central objective of the Land Use Element.

The transportation issues discussed in the Circulation Element are also directly related to the Noise Element. Noise from transportation is largely responsible for excessive noise levels in certain locations in urban environments. Projected noise distribution, depicted as noise contours, is corollary to the Circulation Plan. Noise policies and implementation are largely based on the Circulation Element and are aimed to minimize the effects of transportation noise on current and planned land uses.

The Conservation/Open Space Element is also related to the Noise Element. Enjoyment of parks and open spaces can be diminished by excessive noise, and noise information provided in the Noise Element should be considered in planning new recreational areas. At the same time, where appropriate, open space areas can serve as effective buffers between sensitive land uses and noise producers. 1397

NOISE ELEMENT

ALISO VIEJO GENERAL P LAN
N-3

ISSUES, GOALS, AND POLICIES
Some parts of Aliso Viejo are subject to high noise levels, which can reduce quality of life in residential neighborhoods and for certain other sensitive uses, like churches and schools. Consideration of noise sources in the planning process, combined with identification of affected areas can minimize the impacts of noise on the community.

Noise Element goals, policies and implementation address three issues: (1) avoiding the negative impacts of noise through land use planning and noise reduction measures; (2) minimizing the impact of transportation related noise; and (3) minimizing the impact of non-transportation related noise.

NOISE AND LAND USE PLANNING
Consideration of the sources and recipients of noise early in the land use planning and development process can be an effective way to reduce the impact of noise on the community. Consideration should be given to both reducing noise in severely impacted areas through rehabilitative improvements and avoiding potential noise impacts through effective land use planning.

Policy N-1.1 Ensure that construction and occupancy of new development are compatible with, and do not exceed thresholds defining the acceptable noise environment in surrounding areas.

Policy N-1.2 Require inclusion of noise-reducing design features in development projects to address the impact of noise on residential development.

TRANSPORTATION RELATED NOISE
Excessive noise levels in Aliso Viejo are caused primarily by traffic on the San Joaquin Hills Transportation Corridor (SR-73) and major thoroughfares. Reduction of transportation-related noise levels is desired to improve quality of life in all neighborhoods and for other noise-sensitive land uses.

Goal
N-2 Minimize transportation-related noise impacts.

Policy N-2.1 Ensure noise impacts generated by motorized vehicles are minimized through the use of noise attenuation measures on City streets.

Policy N-2.2 Control truck traffic routing within the City.

Goal
N-1
Minimize the impact of point source noise and ambient noise levels throughout the community.
1398

NOISE ELEMENT

ALISO VIEJO GENERAL P LAN
N-4
Policy N-2.3 Require inclusion of sound-reducing design measures in development projects impacted by transportation-related noise.

Policy N-2.4 Encourage use of alternative transportation technologies that minimize noise impacts.

NON-TRANSPORTATION RELATED NOISE
Noise is also associated with construction activity, manufacturing or business operations, and everyday activities in Aliso Viejo neighborhoods, such as leafblowing and lawnmowing.

Goal
N-3 Minimize noise impacts from sources other than transportation.

Policy N-3.1 Ensure stationary noise impacts on sensitive receptors and noise emanating from construction activities, private developments/residences, landscaping activities and special events are minimized.

Policy N-3.2 Require that mixed-use structures and areas be designed to prevent transfer of noise and vibration from commercial uses to residential uses.
1399

NOISE ELEMENT

ALISO VIEJO GENERAL P LAN
N-5

NOISE PLAN
As the population of Aliso Viejo and the surrounding region increases, noise levels associated with transportation and non-transportation related sources will also increase. The City has established goals and policies (listed in the previous section) to safeguard the community from excessive noise levels as the ambient noise level in the community rises. The Noise Plan describes the approach for achieving this aim and provides a general outline of action programs. As an extension of the Noise Plan, noise implementation contained in Appendix A of the General Plan describes specific actions that the City will take to protect the overall quality of life in the community.

NOISE POLICY MAP
Figure N-1 presents graphically the City’s noise policies and plan. The Noise Policy Map presents the locations of future noise contours surrounding City roadways, within which land use compatibility and noise mitigation requirements outlined in the Noise Plan will be evaluated and required as needed as a part of development review. In addition, the map identifies the location of several “sensitive receptors”.

These schools, child care facilities, senior housing complexes, churches, and other similar facilities should be protected from additional noise intrusions associated with new development or roadway improvements, to the extent feasible. As applicable, the Noise Plan refers to the Policy Map for identification of significant locations, conditions, or development requirements.

NOISE AND LAND USE PLANNING
Accumulation of noise from transportation activities and stationary sources determines the overall noise environment within a community. Noise generated from automobile use, trucking, airport and rail operations is referred to as transportation related noise, while noise from stationary sources such as commercial establishments, machinery, air conditioning systems, compressors and landscape maintenance equipment is typically referred to as non-transportation noise. Noise is most problematic when it affects noise sensitive land uses that include, but are not limited to residences, schools, hospitals, religious meetings and recreational areas. These uses are considered sensitive because the presence of excessive noise may interrupt normal activities typically associated with the use. Sensitive receptor sites in Aliso Viejo are identified in the Noise Policy Map (Figure N-1). Consideration of noise sources, sensitive land uses, and information regarding the future noise environment leads to implementation of effective ways to avoid noise impacts.

Measuring Noise
Noise generally is defined as unwanted or intrusive sound. Because noise consists of pitch, loudness, and duration, describing noise with a single unit of measure presents a challenge. The A-weighted decibel scale (dB(A)) has been developed to describe the loudness of a sound or sound environment based on the sensitivity of the human ear.
1400

NOISE ELEMENT

ALISO VIEJO GENERAL P LAN
N-6
The dB(A) descriptor only reports noise from a single source or combination of sources at a point in time.

To allow a more comprehensive description of the noise environment, Federal and State agencies have established noise and land use compatibility guidelines that use averaging approaches to noise measurement. Two measurement scales commonly used in California are the Community Noise Equivalent Level (CNEL) and the day-night level (Ldn). To account for increased human sensitivity at night, the CNEL level includes a 5-decibel penalty on noise during the 7:00 a.m. to 10:00 p.m. time period and a 10-decibel penalty on noise during the 10:00 p.m. to 7:00 a.m. time period. The Ldn level includes only the 10 decibel weighting for late-night noise. These values are nearly identical for all but unusual noise sources.

Noise Standards and Land Use Compatibility
Table N-1 summarizes County of Orange residential noise standards adopted by the City of Aliso Viejo.

The standards represent the maximum acceptable noise levels as measured from any residential property in the City. Accordingly, it is unlawful to cause the noise level on any residential property to exceed the exterior noise standards: 1) for a cumulative period of more than thirty minutes in any hour; 2) plus five dB(A) for a cumulative period of more than 15 minutes in any hour; 3) plus 10 dB(A) for a cumulative period of more than five minutes in any hour; 4) plus 15 dB(A) for a cumulative period of more than one minute in any hour; or 5) plus 20 dB(A) for any period of time. In addition, any noise that exceeds the interior noise standards established for residential uses: 1) for a cumulative period of more than five minutes in any hour; 2) plus five dB(A) for a cumulative period of more than one minute in any hour; or 3) plus 10 dB(A) for any period of time, is unlawful.

Table N-1
Orange County Residential Noise Standards

Daytime Noise Standards
(7am to 10pm)
Nighttime Noise Standards
(10pm to 7am)
Interior Noise Standards 55 dB(A) 45 dB(A)
Exterior Noise Standards 55 dB(A) 50 dB(A)
Source: County of Orange Code of Ordinances, 2003.

Note: Standards are based on measurements taken from any residential property in the City. 1401

NOISE ELEMENT

ALISO VIEJO GENERAL P LAN
N-7
Figure N-1
Noise Policy Map
11x17” Color
1402

NOISE ELEMENT

ALISO VIEJO GENERAL P LAN
N-8
Back Side of 11x17” Page
1403

NOISE ELEMENT

ALISO VIEJO GENERAL P LAN
N-9
The City’s noise standards serve as the basis for the land use compatibility guidelines presented in Table N-2. A project is considered to be compatible with the noise environment if the noise level generated by the project falls within Zone A or Zone B. If the anticipated noise level of a proposed project falls into Zone A, typically no mitigation is needed and if it falls into Zone B, minor mitigation may be required to meet City and State Title 24 noise standards. All project proponents must demonstrate that noise standards have been met prior to human occupation of a building.

If the noise level of a proposed project falls within Zone C, substantial mitigation is likely needed to meet City noise standards. Mitigation may include construction of noise barriers, and/or the inclusion of substantial building sound insulation. Projects in Zone C can be successfully mitigated; however, project proponents with a project in Zone C must demonstrate that the noise standards can be met prior to issuance of a building permit. If noise levels of a proposed project fall within Zone D, the project is clearly incompatible with the noise environment and should not be approved.

The City Planning Director acts as the noise control coordinator, while Aliso Viejo Police Services is responsible for abating nuisance noises. This delegation of responsibility allows consistent and continual enforcement of the noise standards.

Noise Contours and Impacted Areas

Noise contours, based on the location of major noise sources, describe the noise environment within the community. These contours outline areas of equal noise exposure. Information about existing and projected land use development and transportation activity has been used to estimate future noise contours for Aliso Viejo.

Future noise contours for Aliso Viejo are displayed on the Noise Policy Map (Figure N-1). These contours will guide land use and development decisions to address potential noise issues. Noise impacted areas are those areas that fall within the 60 dB(A) CNEL or greater noise contours. An acoustical analysis must be prepared prior to approval of a noise sensitive project proposed within an identified noise impact area in order to assess the impact in more detail. The analysis must show that the project is designed to attenuate noise to meet the City’s noise standards as set forth in Tables N-1 and N-2 in order to receive approval.

In addition, noise producing land uses will be evaluated using the standards in Tables N-1 and N-2 to ensure that proposed land uses do not adversely impact the current noise environment. If proposed project designs do not meet noise standards, mitigation will be recommended. If the analysis demonstrates that the noise standards can be met by implementing the mitigation measures, the project can be approved conditioned upon those measures. Noise attenuation measures may include soundwalls, berms, and other noise-reducing devices.
1404

NOISE ELEMENT

ALISO VIEJO GENERAL P LAN
N-10
Table N-2
Noise/Land Use Compatibility Matrix

Community Noise Exposure (Ldn or CNEL) Land Use 50 55 60 65 70 75 80 85

Residential

Transient Lodging – Motel, Hotel

Schools, Libraries, Churches,
Hospitals, Nursing Homes

Auditoriums, Concert Halls,
Amphitheaters
Sports Arena, Outdoor Spectator
Sports

Playgrounds, Parks

Golf Course, Riding Stables,
Water Recreation, Cemeteries

Office Buildings, Business
Commercial, and Professional

Industrial, Manufacturing,
Utilities, Agriculture
Source: Modified by CBA from 1998 State of California General Plan Guidelines.

ZONE A - Normally Acceptable: Specified land use is satisfactory, based upon the assumption that any buildings involved meet conventional Title 24 construction standards. No special noise insulation requirements.

ZONE B - Conditionally Acceptable: New construction or development shall be undertaken only after a detailed noise analysis is made and noise reduction measures are identified and included in the project design.

ZONE C- Normally Unacceptable: New construction or development is discouraged. If new construction is proposed, a detailed analysis is required, noise reduction measures must be identified, and noise insulation features included in the design.

ZONE D- Clearly Unacceptable: New construction or development clearly should not be undertaken.

1405

NOISE ELEMENT

ALISO VIEJO GENERAL P LAN
N-11
Portions of the community fall within the 65 dB(A) CNEL noise contour as depicted in the Airport Environs Land Use Plan (AELUP) for the former Marine Corps Air Station El Toro. At the time this land was developed, the type and intensity of uses were restricted due to noise impacts from the former Air Station. Impacted areas include a broad spectrum of land uses such as business parks, residential areas, and open spaces. Based on provisions within the AELUP, all types of residential uses are normally unacceptable in 65 dB(A) CNEL areas.

Opportunities to intensify areas that were previously within this unacceptable noise contour have emerged in neighboring communities following closure of the Air Station, and future opportunities for such redevelopment exist within portions of Aliso Viejo. The City will continue to monitor the status of the El Toro AELUP and opportunities for appropriate redevelopment of areas within the contour at higher intensities, or with uses that would not have been permitted before closure of the Air Station.

Construction Standards

The City of Aliso Viejo will continue to enforce the provisions of the California Energy Code. Energy Code standards specify that combined indoor noise for multi-family living spaces shall not exceed 45 dB(A) CNEL and must be implemented when the outdoor noise level exceeds 60 dB(A) CNEL. The Noise Policy Map (Figure N-1) can be used to determine when and where it is appropriate to implement this standard.

The standard must be applied to all new hotels, motels, and multifamily residential development.

TRANSPORTATION RELATED NOISE

Transportation activity is a significant contributor of noise to the overall noise environment within Aliso Viejo. Transportation related noise is primarily concentrated along the transportation corridors that traverse the community such as State Route 73, major arterials and collector roads.

Noise Control at Reception Sites
The City has little direct control over noise produced by transportation sources since the State is responsible for regulating motor vehicle noise. Therefore, City noise programs focus on reducing the impact of transportation noise on the community.

The most effective ways to mitigate transportation noise impacts on the community are through utilization of a design review process, and implementation of the California Environmental Quality Act (CEQA).

Identification of potential impacts from transportation noise will occur during these stages of the development process and mitigation measures may be required to meet City noise standards identified in this Element. The most common ways to reduce transportation-related noise impacts are through site planning, landscaping, use of natural topography, and the design and construction of noise barriers. Small noise reductions can also be achieved by use of setbacks and landscaping.
1406

NOISE ELEMENT

ALISO VIEJO GENERAL P LAN
N-12
Noise barriers should be included in roadway and freeway designs and improvements. The City supports efforts by Caltrans and the Transportation Corridor Authority (TCA) to provide acoustical protection for noise sensitive uses along transportation corridors. Additionally, the City will request that barriers be included in any future improvement projects along SR-73 to mitigate identified or potential long- and short-term noise impacts to nearby residences and businesses from roadway expansion or construction related activity. The City continues to promote the use of berms, embankments, landscaping, setbacks, and architectural design where appropriate and effective, rather than conventional wall barriers to enhance community aesthetics.

Noise Control at the Source

Reducing noise at the source is the most efficient and effective way to control noise from transportation systems. The California Vehicle Code contains noise regulations pertaining to the operation of all vehicles on public roads, which are enforced through coordination with the California Highway Patrol and the Orange County Sheriff’s Department. While the City is ultimately limited in its ability to restrict noise at the source, Aliso Viejo regulates traffic flow and coordinates with the California Highway Patrol and the Orange County Sheriff’s Department to enforce speed limits to reduce traffic noise.

NON-TRANSPORTATION RELATED NOISE

In addition to transportation related noise, excessive noise generated by non-transportation sources, such as commercial and industrial centers, agricultural activities, and restaurants and bars, have the potential to impact sensitive receptors. Enforcement of City noise requirements, analysis of potential noise impacts during the site design review process, and compliance with CEQA are the best means to protect sensitive receptors. Potential noise impacts can be identified during the preliminary stages of the development process and mitigation measures can be imposed.

When reviewing proposed non-residential projects, the City considers noise generation and potential impacts to surrounding development. New development can be made compatible with the noise environment by utilizing noise/land use compatibility standards and the Noise Policy Map as a guide for future planning and development decisions. An acoustical analysis is required for projects that will generate noise potentially affecting sensitive receptors. Where significant impacts are identified, mitigation measures are required. Mitigation measures that could be applied when reviewing projects include acoustically treated and/or quiet designs for furnaces, fans, motors, compressors, valves, pumps and other mechanical equipment. Noise resulting from special one-time events should be minimized as well. The City may also require limited delivery hours and/or hours of operation in order to minimize impacts to adjacent residential uses. In addition, all City departments must comply with State and federal OSHA standards. Any new equipment or vehicles purchased by the City will comply with local, State and federal noise standards, and the City will encourage landscaping contractors to utilize modern noisereducing equipment. 1407

NOISE ELEMENT

ALISO VIEJO GENERAL P LAN
N-13
Noise Control Ordinance

Upon incorporation, the City adopted the County of Orange Noise Control Ordinance. This Ordinance is designed to protect people from non-transportation related noise sources such as construction activity, machinery and pumps, and air conditioners. Enforcing the Ordinance requiring proposed development projects to demonstrate compliance ensures that adjacent properties are not exposed to excessive noise from stationary sources or nuisances. The Ordinance will be reviewed periodically for adequacy and amended as needed to address community needs and development patterns.

The City also has the opportunity to control noise and vibration transfers between adjacent land uses.

Particular problems arise in cases where noise-producing uses are located immediately adjacent to sensitive uses, such as business park areas near residences or schools. Mixed use projects also present unique problems in this area, such as when restaurants with nighttime entertainment are located below residential units. The City’s Zoning Ordinance or any Specific Plan developed following adoption of the General Plan will include standards regulating noise and vibration transfers within mixed use development projects.
1408

NOISE ELEMENT

ALISO VIEJO GENERAL P LAN
N-14
This page is left intentionally blank.
1409
Chapter 8.12

NOISE CONTROL
1 Sections:

8.12.010 Purpose.

8.12.020 Declaration of policy.

8.12.030 Definitions.

8.12.040 Noise level measurement criteria.

8.12.050 Exterior noise standards.

8.12.060 Interior noise standards.

8.12.070 Exemptions.

8.12.080 Schools, hospitals and churches – Special provisions.

8.12.090 Manner of enforcement.

8.12.100 Violations.

Prior legislation: Ord. 2002-033.

8.12.010 Purpose.

The purpose of this chapter is to establish noise standards and to protect the health, safety, welfare, and living/working environments in the city. [Ord. 2010-126 § 1 (Exh. A)].

8.12.020 Declaration of policy.

A. It is hereby declared to be the policy of the city to control unnecessary, excessive, and annoying sounds from all sources as specified in this chapter.

B. It is determined that certain sound levels are detrimental to the public health, welfare, and safety, and contrary to public interest. [Ord. 2010-126 § 1 (Exh. A)].

8.12.030 Definitions.

The following definitions apply to the use of these terms for the purposes of this chapter:
“Ambient noise level” means the all-encompassing noise level associated with a given environment, being a composite of sounds from all sources, excluding the alleged offensive noise, at the location and approximate time at which a comparison with the alleged offensive noise is to be made.

The Aliso Viejo Municipal Code is current through Ordinance 2025-244, passed March 5, 2025.

Aliso Viejo Chapter 8.12 NOISE CONTROL1 Page 1 of 6
1410
“Cumulative period” means an additive period of time composed of individual time segments which may be continuous or interrupted.
“Decibel (dB)” means a unit which denotes the ratio between two quantities which are proportional to power:
the number of decibels corresponding to the ratio of two amounts of power to 10 times the logarithm to the base 10 of this ratio.
“Density” means the number of dwelling units per gross acre of land as established in AVMC Title 15. “Dwelling unit” means a single unit providing complete, independent living facilities for one or more persons including permanent provisions for living, sleeping, eating, cooking and sanitation. “Emergency machinery, vehicle, or work” means any machinery, vehicle, or work used, employed, or performed in an effort to protect, provide, or restore safe conditions in the community or for the citizenry, or work by private or public utilities when restoring utility service. “Fixed noise source” means a stationary device which creates sounds while fixed or motionless, including but not limited to industrial and commercial machinery and equipment, pumps, fans, compressors, generators, air conditioners, leaf blowers, public address systems and refrigeration equipment. “Grading” means any excavating or filling of earth material, or any combination thereof, conducted at a site to prepare the site for construction or other improvements thereon. “Impact noise source” means the noise produced by the collision of one mass in motion with a second mass which may be either in motion or at rest.
“Mobile noise source” means any noise source other than a fixed noise source. “Noise level” means the “A” weighted sound pressure level in decibels obtained by using a sound level meter at slow response with a reference pressure of 20 micronewtons per square meter. The unit of measurement shall be designated as dB(A).
“Nonresidential property” means any parcel of real property other than residential property. “Residential property” means a parcel of real property which is developed and used either in part or in whole for residential purposes, other than transient uses such as hotels and motels. “Simple tone noise” means a noise characterized by a predominant frequency or frequencies so that other frequencies cannot be readily distinguished.
“Sound level meter” means an instrument meeting American National Standard Institute’s Standard S1.4-1971 for Type 1 or Type 2 sound level meters or an instrument and the associated recording and analyzing equipment which will provide equivalent data.
“Sound pressure level, in decibels” means 20 times the logarithm to the base 10 of the ratio of the pressure of The Aliso Viejo Municipal Code is current through Ordinance 2025-244, passed March 5, 2025.

Aliso Viejo Chapter 8.12 NOISE CONTROL1 Page 2 of 6
1411
the sound to a reference pressure, which reference pressure shall be explicitly stated. [Ord. 2010-126 § 1 (Exh. A)].

Cross-reference: definitions generally, AVMC 1.02.010.

8.12.040 Noise level measurement criteria.

Any noise level measurements made pursuant to the provisions of this chapter shall be performed using a sound level meter. Exterior noise levels shall be measured at any point on the affected property. Interior noise levels shall be measured within the affected dwelling unit at a point at least four feet from the wall, ceiling, or floor nearest the alleged noise source with the windows of the affected dwelling unit closed. [Ord. 2010-126 § 1 (Exh. A)].

8.12.050 Exterior noise standards.

A. The following exterior noise standards, unless otherwise specifically indicated, shall apply to all residential property within the city:

Residential Exterior Noise
Standards
Noise
Level
Time
Period
Density of
less than 10
DU/acre
50 dB(A) 7:00 a.m. –
10:00 p.m.
45 dB(A) 10:00 p.m.
– 7:00 a.m.

Density of
10 DU/acre
or more
55 dB(A) 7:00 a.m. –
10:00 p.m.
50 dB(A) 10:00 p.m.
– 7:00 a.m.

In the event the noise consists entirely of impact noise, simple tone noise, speech, music, or any combination thereof, each of the above noise levels shall be reduced by five dB(A).

B. The following exterior noise standards, unless otherwise specifically indicated, shall apply to all nonresidential property within the city. If a noise affects both residential and nonresidential property, then the applicable noise standard shall be the arithmetic mean of the applicable standards that apply to residential and nonresidential property.

Nonresidential Exterior Noise
Standards
Noise Time
The Aliso Viejo Municipal Code is current through Ordinance 2025-244, passed March 5, 2025.

Aliso Viejo Chapter 8.12 NOISE CONTROL1 Page 3 of 6
I I I
1412
Noise
Level
Time
Period
Commercial 65
dB(A)
7:00
a.m. –
10:00
p.m.
60 dB(A)
10:00
p.m. –
7:00
a.m.

Manufacturing/Industrial 70
dB(A)
24 hours
per
day
In the event the noise consists entirely of impact noise, simple tone noise, speech, music, or any combination thereof, each of the above noise levels shall be reduced by five dB(A).

C. It shall be unlawful for any person at any location within the city to create any noise, or to allow the creation of any noise on property owned, leased, occupied, or otherwise controlled by the person, when the foregoing causes the noise level, when measured on any other parcel, to exceed:

1. The noise standard for a cumulative period of more than 30 minutes in any hour.

2. The noise standard plus five dB(A) for a cumulative period of more than 15 minutes in any hour.

3. The noise standard plus 10 dB(A) for a cumulative period of more than five minutes in any hour.

4. The noise standard plus 15 dB(A) for a cumulative period of more than one minute in any hour.

5. The noise standard plus 20 dB(A) for any period of time.

6. In the event the ambient noise level exceeds any of the applicable standards when the source of the noise is not operating, the ambient noise level shall become the standard. [Ord. 2013-151 § 3 (Exh. A); Ord. 2013-149 § 1; Ord. 2010-126 § 1 (Exh. A)].

8.12.060 Interior noise standards.

A. The following interior noise standards, unless otherwise specifically indicated, shall apply to all residential property within the city:

Residential Interior Noise
Standards
The Aliso Viejo Municipal Code is current through Ordinance 2025-244, passed March 5, 2025.

Aliso Viejo Chapter 8.12 NOISE CONTROL1 Page 4 of 6
1413
Noise Level Time Period
55 dB(A) 7:00 a.m. – 10:00
p.m.
45 dB(A) 10:00 p.m. – 7:00
a.m.

In the event the noise consists entirely of impact noise, simple tone noise, speech, music, or any combination thereof, each of the above noise levels shall be reduced by five dB(A).

B. It shall be unlawful for any person at any location within the city to create any noise, or to allow the creation of any noise on property owned, leased, occupied, or otherwise controlled by the person, when the foregoing causes the noise level, when measured within the interior of any other dwelling unit on any residential parcel within the city to exceed:

1. The interior noise standard for a cumulative period of more than five minutes in any hour.

2. The interior noise standard plus five dB(A) for a cumulative period of more than one minute in any hour.

3. The interior noise standard plus 10 dB(A) for any period of time.

C. In the event the ambient noise level exceeds either of the first two noise level categories above, the cumulative period applicable to the category shall be increased to reflect the ambient noise level. In the event the ambient noise level exceeds the third noise limit category, the maximum allowable noise level under that category shall be increased to reflect the maximum ambient noise level. [Ord. 2010-126 § 1 (Exh. A)].

8.12.070 Exemptions.

The following activities shall be exempt from the provisions of this chapter:

A. Activities conducted on the grounds of any public or private nursery, elementary, intermediate or secondary school or college, or day care home.

B. “Special events” as defined in AVMC 11.05.020 provided said events are conducted pursuant to a special events permit issued pursuant to Chapter 11.05 AVMC.

C. Outdoor gatherings, public dances and shows, provided the events are conducted pursuant to a permit issued by the city.

D. Any mechanical device, apparatus, or equipment used, related to or connected with emergency machinery, vehicle or work.

E. Noise sources associated with construction, repair, remodeling, or grading of any real property, provided the activities do not take place between the hours of 8:00 p.m. and 7:00 a.m. on weekdays, 8:00 p.m. and 8:00 The Aliso Viejo Municipal Code is current through Ordinance 2025-244, passed March 5, 2025.

Aliso Viejo Chapter 8.12 NOISE CONTROL1 Page 5 of 6
1414
1 a.m. on Saturday, or at any time on Sunday or a federal holiday.

F. Noise sources associated with the maintenance of real property, provided the activities take place between the hours of 7:00 a.m. and 8:00 p.m. on any day except Sunday or a federal holiday, or between the hours of 9:00 a.m. and 8:00 p.m. on Sunday or a federal holiday.

G. Any activity to the extent regulation thereof has been preempted by state or federal law.

H. Noise sources associated with solid waste collection and removal, provided such activities take place between 7:00 a.m. and 6:00 p.m. Monday through Friday where audible in residential areas; or between 7:00 a.m. and 6:00 p.m. on Saturdays where audible in residential areas; or between 5:00 a.m. and 9:00 p.m. any day where such activity is not audible in residential areas; or as otherwise provided in an approved franchise agreement between a waste hauler and the city. [Ord. 2010-126 § 1 (Exh. A)].

8.12.080 Schools, hospitals and churches – Special provisions.

It shall be unlawful for any person to create any noise which causes the noise level at any school, hospital or church while the same is in use for its intended purpose to exceed the noise limits as specified in AVMC

8.12.050(A) or which causes the noise level to unreasonably interfere with the use of such institutions for their intended purpose or which unreasonably disturbs or annoys students, patients, or attendees in such institutions, provided conspicuous signs are displayed in three separate locations within one-tenth of a mile of the institution indicating the presence of a school, church or hospital. [Ord. 2010-126 § 1 (Exh. A)].

8.12.090 Manner of enforcement.

A. The chief of police services, or designee, is directed to enforce the provisions of this chapter.

B. No person shall interfere with, oppose, or resist any authorized person charged with the enforcement of this chapter while the person is engaged in the performance of his/her duty. [Ord. 2010-126 § 1 (Exh. A)].

Cross-reference: interference with public officers prohibited, AVMC 8.20.040.

8.12.100 Violations.

Any person violating any of the provisions of this chapter shall be deemed guilty of a misdemeanor and/or such violation shall constitute a public nuisance. [Ord. 2010-126 § 1 (Exh. A)].

Cross-reference: violations and penalties generally, Chapter 1.06 AVMC.

Cross-references: animal noise nuisances, AVMC 6.04.030; solid waste collection vehicles, AVMC

7.05.150; disturbances in residential areas during sleeping hours, Chapter 8.10 AVMC.

The Aliso Viejo Municipal Code is current through Ordinance 2025-244, passed March 5, 2025.

Aliso Viejo Chapter 8.12 NOISE CONTROL1 Page 6 of 6
1415
Appendix B
Photographs, Field Sheets, and Measured Noise Data
1416
Project: Engineer: C. Stokes Date: 8/6/2025
JN:

City: Aliso Viejo, CA
Sound Level Meter: Calibration Record: Conditions:

Piccolo II Meter Input (dB) Time Date H: 88, L: 62
Serial #: P0222082204 1 94 1:21 PM 8/6/2025 Varies
P0222082205 2 94 1:23 PM 8/6/2025 Varies
P0221010801 3 94 1:24 PM 8/6/2025 Clear
4 -- --
Calibrator:

BSWA
Serial #: 500732
Meter Settings:

A-Weighted Linear Slow 1/1 Octave 60 Minute Intervals
C-Weighted Impulse Fast 1/3 Octave L(n) Percentile Values Notes: Measurement Type:

Long-term (24-hour)
Short-term
= Noise Monitoring Location
Wind Direction:

Skies:

Noise measurements were taken at one-hour intervals for a duration of 24 hours. The primary sources of environmental noise impacting the project site are commercial activity at adjacent properties, fire station activity, and roadway activity along Aliso Viejo Parkway and Pacific Park Drive.

Field Sheet
Pacific Park Townhome Project
Measurement Address: 27061-081 Aliso Creek Road
Temperature (°F):

Windspeed (m.p.h.):
2827-2025-
02 1
2 1
3 G
□
0 ENGINEERING
GROUP INC.
□ G □ G
□ □ □ G
1417
Project: Engineer: C. Stokes Date: 8/6/2025
JN:

City: Aliso Viejo, CA
Notes:

47.0 Field Photos - Noise Monitoring Location 1 (L-1)
Pacific Park Townhome Project
Measurement Address: 27071 Aliso Creek Road
Noise Monitoring Location 1 (L-1) was taken near the northern boundary of the project site, approximately 155 feet south of the centerline of Pacific Park Drive. 2827-2025-
02 Meter 1

ENGINEERING
GROUP INC.
1418
Time Leq CNEL
12:00 AM 51.6 64.0
1:00 AM 49.1 64.0
2:00 AM 62.9 64.0
3:00 AM 47.7 64.0
4:00 AM 51.1 64.0
5:00 AM 54.5 64.0
6:00 AM 56.9 64.0
7:00 AM 58.4 64.0
8:00 AM 62.1 64.0
9:00 AM 59.6 64.0
10:00 AM 57.3 64.0
11:00 AM 57.4 64.0
12:00 PM 61.6 64.0
1:00 PM 55.8 64.0
2:00 PM 56.5 64.0
3:00 PM 59.0 64.0
4:00 PM 61.1 64.0
5:00 PM 59.1 64.0
6:00 PM 57.0 64.0
7:00 PM 63.0 64.0
8:00 PM 58.3 64.0
9:00 PM 56.3 64.0
10:00 PM 55.3 64.0
11:00 PM 58.1 64.0
Day Min: 55.8
Night Min 47.7
Noise Monitoring Location 1 Noise Monitoring Results (dBA Leq and CNEL)

0.0 10.0

20.0 30.0

40.0 50.0

60.0 70.0

80.0 90.0
100.0
12:00 AM
1:00 AM2:00 AM3:00 AM4:00 AM5:00 AM6:00 AM7:00 AM8:00 AM9:00 AM 10:00 AM11:00 AM
12:00 PM
1:00 PM2:00 PM3:00 PM4:00 PM5:00 PM6:00 PM7:00 PM8:00 PM9:00 PM 10:00 PM11:00 PM
Noise Level (dBA)
L-1 DBA LEQ AND CNEL
Leq CNEL

ENGINEERING
GROUP INC.
--
1419
PROJECT: Pacific Park Townhome Project JOB #: 2827-25-2 NOISE METER: Piccolo II SLM, 24-Hour Measurement DATE: 06-Aug-25 LOCATION: 1 BY: C. Stokes
Time Leq Lmax Lmin L2 L8 L25 L50
12:00 AM 51.6 66.6 41.9 59.4 56.1 51.2 47.8
1:00 AM 49.1 66.3 39.0 58.3 52.4 46.9 43.8
2:00 AM 62.9 91.9 41.0 61.7 52.9 47.2 44.6
3:00 AM 47.7 68.0 40.5 55.6 50.8 46.4 44.0
4:00 AM 51.1 68.2 41.6 59.6 55.5 49.7 46.7
5:00 AM 54.5 76.8 44.9 60.7 58.3 54.5 51.5
6:00 AM 56.9 68.6 49.5 62.7 60.7 57.8 55.0
7:00 AM 58.4 67.9 51.1 64.5 61.9 59.3 56.5
8:00 AM 62.1 91.0 49.0 64.9 62.3 59.4 56.5
9:00 AM 59.6 82.5 49.0 65.4 61.2 58.7 56.2
10:00 AM 57.3 74.1 47.7 63.5 60.4 57.9 55.2
11:00 AM 57.4 75.4 47.9 63.7 60.9 57.9 55.1
12:00 PM 61.6 90.7 47.6 65.1 61.2 58.1 55.4
1:00 PM 55.8 68.2 46.1 62.1 59.3 56.5 54.0
2:00 PM 56.5 73.8 46.5 63.5 59.7 57.1 54.2
3:00 PM 59.0 85.7 46.1 63.4 60.0 56.8 54.1
4:00 PM 61.1 91.6 46.7 63.5 60.0 57.0 54.6
5:00 PM 59.1 81.6 46.5 65.1 61.3 58.1 55.3
6:00 PM 57.0 72.9 45.9 63.0 60.5 57.9 55.0
7:00 PM 63.0 93.1 45.7 64.7 60.9 57.4 54.4
8:00 PM 58.3 82.5 48.1 63.9 60.2 57.6 54.9
9:00 PM 56.3 73.3 48.4 62.0 59.6 56.9 54.5
10:00 PM 55.3 74.2 46.1 61.5 58.5 55.5 52.8
11:00 PM 58.1 83.7 42.9 64.0 59.3 56.2 51.4
Daytime 59.2 93.1 45.7 63.9 60.6 57.7 55.0
Nighttime 56.7 91.9 39.0 60.9 56.9 53.2 49.9
Noise Monitoring Location 1 Noise Monitoring Results (dBA Leq and Ln)

0.0 10.0

20.0 30.0

40.0 50.0

60.0 70.0

ENGINEERING
GROUP INC.
-- -- -- -- -- -- --
1420
Project: Engineer: C. Stokes Date: 8/6/2025
JN:

City: Aliso Viejo, CA
Notes:

47.0 Field Photos - Noise Monitoring Location 2 (L-2)
Pacific Park Townhome Project
Measurement Address: 27061 Aliso Creek Road
Noise Monitoring Location 2 (L-2) was taken near the eastern boundary of the project site, approximately 150 feet west of the centerline of Aliso Creek Road. 2827-2025-
02 Meter 2

ENGINEERING
GROUP INC.
1421
Time Leq CNEL
12:00 AM 53.0 65.6
1:00 AM 52.1 65.6
2:00 AM 52.4 65.6
3:00 AM 53.8 65.6
4:00 AM 54.9 65.6
5:00 AM 57.5 65.6
6:00 AM 61.6 65.6
7:00 AM 63.0 65.6
8:00 AM 63.7 65.6
9:00 AM 64.1 65.6
10:00 AM 62.4 65.6
11:00 AM 62.5 65.6
12:00 PM 62.7 65.6
1:00 PM 61.9 65.6
2:00 PM 61.9 65.6
3:00 PM 61.3 65.6
4:00 PM 61.6 65.6
5:00 PM 62.0 65.6
6:00 PM 62.9 65.6
7:00 PM 61.3 65.6
8:00 PM 60.5 65.6
9:00 PM 60.1 65.6
10:00 PM 60.0 65.6
11:00 PM 61.4 65.6
Day Min: 60.1
Night Min 52.1
Noise Monitoring Location 2 Noise Monitoring Results (dBA Leq and CNEL)

0.0 10.0

20.0 30.0

40.0 50.0

60.0 70.0

ENGINEERING
GROUP INC.
--
1422
PROJECT: Pacific Park Townhome Project JOB #: 2827-25-2 NOISE METER: Piccolo II SLM, 24-Hour Measurement DATE: 06-Aug-25 LOCATION: 2 BY: C. Stokes
Time Leq Lmax Lmin L2 L8 L25 L50
12:00 AM 53.0 66.6 42.0 61.4 57.9 51.7 48.6
1:00 AM 52.1 72.5 39.8 61.3 56.3 49.3 46.6
2:00 AM 52.4 71.2 40.4 61.1 56.9 49.4 45.1
3:00 AM 53.8 71.7 40.8 64.1 58.7 49.1 45.6
4:00 AM 54.9 74.5 41.5 63.9 59.8 52.6 48.0
5:00 AM 57.5 69.9 46.3 65.0 62.1 58.2 53.7
6:00 AM 61.6 72.6 50.7 68.0 65.9 62.8 59.4
7:00 AM 63.0 72.0 52.3 68.3 66.6 64.4 61.7
8:00 AM 63.7 73.8 51.0 68.8 67.2 64.9 62.5
9:00 AM 64.1 86.9 48.9 68.7 66.9 64.3 61.5
10:00 AM 62.4 72.3 48.1 67.9 66.1 64.0 61.0
11:00 AM 62.5 75.4 49.3 67.8 66.2 63.8 61.1
12:00 PM 62.7 73.5 46.2 68.5 66.8 64.3 60.8
1:00 PM 61.9 77.5 45.8 68.5 65.5 62.7 59.8
2:00 PM 61.9 78.5 45.7 67.1 65.2 62.8 60.2
3:00 PM 61.3 69.9 45.0 66.2 64.6 62.7 60.5
4:00 PM 61.6 74.5 46.6 66.2 64.6 63.0 60.7
5:00 PM 62.0 75.1 48.8 66.6 65.2 63.5 61.2
6:00 PM 62.9 83.2 48.0 67.6 65.3 63.4 61.1
7:00 PM 61.3 71.7 47.5 66.6 65.0 62.8 60.0
8:00 PM 60.5 70.6 47.6 66.2 64.2 61.8 59.0
9:00 PM 60.1 72.6 48.7 66.1 63.8 61.3 58.3
10:00 PM 60.0 83.7 46.7 65.3 62.6 59.7 56.5
11:00 PM 61.4 89.8 45.3 64.7 61.6 58.1 53.2
Daytime 62.1 86.9 45.0 67.4 65.5 63.3 60.6
Nighttime 57.5 89.8 39.8 64.3 61.0 56.8 52.9
Noise Monitoring Location 2 Noise Monitoring Results (dBA Leq and Ln)

0.0 10.0

20.0 30.0

40.0 50.0

60.0 70.0

ENGINEERING
GROUP INC.
-- -- -- -- -- -- --
1423
Project: Engineer: C. Stokes Date: 8/6/2025
JN:

City: Aliso Viejo, CA
Notes:

47.0 Field Photos - Noise Monitoring Location 3 (L-3)
Pacific Park Townhome Project
Measurement Address: 27081 Aliso Creek Road
Noise Monitoring Location 3 (L-3) was taken near the western boundary of the project site, approximately 155 feet east of the centerline of Journey. 2827-2025-
02 Meter 3

ENGINEERING
GROUP INC.
1424
Time Leq CNEL
12:00 AM 45.4 57.2
1:00 AM 45.3 57.2
2:00 AM 56.1 57.2
3:00 AM 44.4 57.2
4:00 AM 44.9 57.2
5:00 AM 51.3 57.2
6:00 AM 52.4 57.2
7:00 AM 55.8 57.2
8:00 AM 52.4 57.2
9:00 AM 54.1 57.2
10:00 AM 51.8 57.2
11:00 AM 49.6 57.2
12:00 PM 51.2 57.2
1:00 PM 51.7 57.2
2:00 PM 51.8 57.2
3:00 PM 51.9 57.2
4:00 PM 55.4 57.2
5:00 PM 53.5 57.2
6:00 PM 49.7 57.2
7:00 PM 50.0 57.2
8:00 PM 47.6 57.2
9:00 PM 47.7 57.2
10:00 PM 47.7 57.2
11:00 PM 47.3 57.2
Day Min: 47.6
Night Min 44.4
Noise Monitoring Location 3 Noise Monitoring Results (dBA Leq and CNEL)

0.0 10.0

20.0 30.0

40.0 50.0

60.0 70.0

ENGINEERING
GROUP INC.
--
1425
PROJECT: Pacific Park Townhome Project JOB #: 2827-25-2 NOISE METER: Piccolo II SLM, 24-Hour Measurement DATE: 06-Aug-25 LOCATION: 3 BY: C. Stokes
Time Leq Lmax Lmin L2 L8 L25 L50
12:00 AM 45.4 58.9 43.8 47.9 46.1 45.3 45.0
1:00 AM 45.3 56.0 43.5 46.9 45.9 45.4 45.1
2:00 AM 56.1 81.8 43.3 52.6 48.6 46.5 45.4
3:00 AM 44.4 52.2 43.2 46.9 44.9 44.4 44.1
4:00 AM 44.9 54.5 43.1 47.0 45.9 45.1 44.6
5:00 AM 51.3 67.2 44.3 61.0 51.2 48.8 48.1
6:00 AM 52.4 66.9 47.0 61.6 54.1 50.8 49.6
7:00 AM 55.8 72.4 49.0 63.2 58.8 55.0 52.0
8:00 AM 52.4 66.3 47.4 57.6 55.5 53.4 50.5
9:00 AM 54.1 73.3 46.5 61.6 57.3 53.7 50.9
10:00 AM 51.8 71.0 46.6 59.4 55.1 51.1 49.0
11:00 AM 49.6 64.8 46.5 54.3 51.8 49.8 48.5
12:00 PM 51.2 69.3 46.6 57.0 53.3 50.3 48.9
1:00 PM 51.7 72.4 46.6 56.9 53.3 50.8 49.1
2:00 PM 51.8 64.0 46.2 60.1 54.7 51.1 49.1
3:00 PM 51.9 72.2 46.5 58.8 54.8 51.4 49.2
4:00 PM 55.4 81.2 46.4 56.7 53.3 50.7 49.2
5:00 PM 53.5 71.8 45.5 59.9 57.3 52.9 49.9
6:00 PM 49.7 65.7 43.5 56.5 53.0 49.8 47.2
7:00 PM 50.0 68.9 43.5 58.6 52.3 49.2 46.4
8:00 PM 47.6 68.1 44.0 52.5 49.7 47.3 45.9
9:00 PM 47.7 62.3 44.2 54.4 49.6 47.0 46.2
10:00 PM 47.7 68.8 44.2 50.6 48.5 46.4 45.7
11:00 PM 47.3 64.3 44.0 52.0 50.6 47.2 45.6
Daytime 52.1 81.2 43.5 58.5 54.5 51.2 49.0
Nighttime 50.5 81.8 43.1 56.1 49.6 47.2 46.4
Noise Monitoring Location 3 Noise Monitoring Results (dBA Leq and Ln)

0.0 10.0

20.0 30.0

40.0 50.0

60.0 70.0

ENGINEERING
GROUP INC.
-- -- -- -- -- -- --
1426
Appendix C
Stationary Noise Calculation Worksheets
1427
Project: Date: 2/10/2026
JN: 2827-2025-02
Noise Source: HVAC Units Engineer: B. Morrison
Location: Nearest adjacent receptor (Nighttime)
OBS DIST= 70.0
DT WALL= 3.0
DT W/OB= 67.0
HTH WALL= 5.0 ********
BARRIER = 0.0 (0=WALL,1=BERM)
OBS HTH= 5.0
NOISE HTH= 3.5 BARRIER+
OBS EL = 0.0 TOPO SHIELDING = -7.60
NOISE EL = 0.0 NOISE HTH EL= 3.5
DROP-OFF= 20.0 (20 = 6 dBA PER DOUBLING OF DISTANCE)
Distance (ft.) Leq Lmax L2 L8 L25 L50
REF LEVEL 3.28 65.0 65.0 65.0 65.0 65.0 65.0
PROJ LEVEL 70 38.4 38.4 38.4 38.4 38.4 38.4
SHIELDING 70 -7.6 -7.6 -7.6 -7.6 -7.6 -7.6
ADJ LEVEL 70 30.8 30.8 30.8 30.8 30.8 30.8
NOISE LEVEL REDUCTION DUE TO DISTANCE = -26.58448393
Stationary Noise Calculations - Based on FHWA-RD-77-108 Pacific Park Townhome Project
Noise Input Data
Noise Output Data (dBA)
D
~ ENGINEERING GROUP INC.
1428
Project: Date: 2/10/2026
JN: 2827-2025-02
Noise Source: HVAC Units Engineer: B. Morrison
Location: Nearest adjacent receptor (Nighttime)
OBS DIST= 125.0
DT WALL= 3.0
DT W/OB= 122.0
HTH WALL= 5.0 ********
BARRIER = 0.0 (0=WALL,1=BERM)
OBS HTH= 5.0
NOISE HTH= 3.5 BARRIER+
OBS EL = 0.0 TOPO SHIELDING = -7.60
NOISE EL = 0.0 NOISE HTH EL= 3.5
DROP-OFF= 20.0 (20 = 6 dBA PER DOUBLING OF DISTANCE)
Distance (ft.) Leq Lmax L2 L8 L25 L50
REF LEVEL 3.28 65.0 65.0 65.0 65.0 65.0 65.0
PROJ LEVEL 125 33.4 33.4 33.4 33.4 33.4 33.4
SHIELDING 125 -7.6 -7.6 -7.6 -7.6 -7.6 -7.6
ADJ LEVEL 125 25.8 25.8 25.8 25.8 25.8 25.8
NOISE LEVEL REDUCTION DUE TO DISTANCE = -31.62072339
Stationary Noise Calculations - Based on FHWA-RD-77-108 Pacific Park Townhome Project
Noise Input Data
Noise Output Data (dBA)
D
~ ENGINEERING GROUP INC.
1429
Project: Date: 2/10/2026
JN: 2827-2025-02
Noise Source: HVAC Units Engineer: B. Morrison
Location: Nearest adjacent receptor (Daytime)
Noise Source Leq Lmax L2 L8 L25 L50
HVAC Unit 30.8 30.8 30.8 30.8 30.8 30.8
HVAC Unit 30.8 30.8 30.8 30.8 30.8 30.8
HVAC Unit 30.8 30.8 30.8 30.8 30.8 30.8
HVAC Unit 30.8 30.8 30.8 30.8 30.8 30.8
HVAC Unit 30.8 30.8 30.8 30.8 30.8 30.8
Total 37.8 37.8 37.8 37.8 37.8 37.8
dB Adder
Pacific Park Townhome Project
Noise Levels (dBA)

ENGINEERING
GROUP INC.
1430
Project: Date: 2/10/2026
JN: 2827-2025-02
Noise Source: HVAC Units Engineer: B. Morrison
Location: Nearest adjacent receptor (Nighttime)
Noise Source Leq Lmax L2 L8 L25 L50
HVAC Unit 25.8 25.8 25.8 25.8 25.8 25.8
HVAC Unit 25.8 25.8 25.8 25.8 25.8 25.8
HVAC Unit 25.8 25.8 25.8 25.8 25.8 25.8
HVAC Unit 25.8 25.8 25.8 25.8 25.8 25.8
HVAC Unit 25.8 25.8 25.8 25.8 25.8 25.8
Total 32.8 32.8 32.8 32.8 32.8 32.8
dB Adder
Noise Levels (dBA)
Pacific Park Townhome Project

ENGINEERING
GROUP INC.
1431
Appendix D
Exterior Land Use Compatibility Calculation
Worksheets
1432
Project: Date: 2/10/2026
JN: 2827-2025-02
Noise Source: Existing Exterior Ambient Noise Levels Engineer: B. Morrison Location: Building facades facing Pacific Park Drive (Noise Monitoring Location 1) OBS DIST= 80.0
DT WALL= 0.0
DT W/OB= 80.0
HTH WALL= 0.0 ********
BARRIER = 0.0 (0=WALL,1=BERM)
OBS HTH= 5.0
NOISE HTH= 5.0 BARRIER+
OBS EL = 0.0 TOPO SHIELDING = 0.00
NOISE EL = 0.0 NOISE HTH EL= 5.0
DROP-OFF= 20.0 (20 = 6 dBA PER DOUBLING OF DISTANCE)
Distance (ft.) CNEL Leq L2 L8 L25 L50
REF LEVEL 150 64.0 -- -- -- -- --
PROJ LEVEL 80 69.5 5.5 5.5 5.5 5.5 5.5
SHIELDING 80 0.0 0.0 0.0 0.0 0.0 0.0
ADJ LEVEL 80 69.5 -- -- -- -- --
NOISE LEVEL REDUCTION DUE TO DISTANCE = 5.460025441
Stationary Noise Calculations - Based on FHWA-RD-77-108 Pacific Park Townhome Project
Noise Input Data
Noise Output Data (dBA)
D
~ ENGINEERING GROUP INC.
1433
Project: Date: 2/10/2026
JN: 2827-2025-02
Noise Source: Existing Exterior Ambient Noise Levels Engineer: B. Morrison Location: Building facades facing Aliso Creek Road (Noise Monitoring Location 2) OBS DIST= 90.0
DT WALL= 0.0
DT W/OB= 90.0
HTH WALL= 0.0 ********
BARRIER = 0.0 (0=WALL,1=BERM)
OBS HTH= 5.0
NOISE HTH= 5.0 BARRIER+
OBS EL = 0.0 TOPO SHIELDING = 0.00
NOISE EL = 0.0 NOISE HTH EL= 5.0
DROP-OFF= 20.0 (20 = 6 dBA PER DOUBLING OF DISTANCE)
Distance (ft.) CNEL Leq L2 L8 L25 L50
REF LEVEL 135 65.6 -- -- -- -- --
PROJ LEVEL 90 69.1 3.5 3.5 3.5 3.5 3.5
SHIELDING 90 0.0 0.0 0.0 0.0 0.0 0.0
ADJ LEVEL 90 69.1 -- -- -- -- --
NOISE LEVEL REDUCTION DUE TO DISTANCE = 3.521825181
Stationary Noise Calculations - Based on FHWA-RD-77-108 Pacific Park Townhome Project
Noise Input Data
Noise Output Data (dBA)
D
~ ENGINEERING GROUP INC.
1434
Appendix E
Construction Noise and Vibration Calculation
Worksheets
1435
Report date: 8/4/2025
Case Description: Pacific Park Townhome Project
Description Land Use Daytime Evening Night
Demolition Residential 65 65 65
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Concrete Saw No 100 89.6 250 0
Dozer No 100 81.7 250 0
Equipment *Lmax Leq
Concrete Saw 75.6 75.6
Dozer 67.7 67.7
Total 75.6 76.3
*Calculated Lmax is the Loudest value.

Roadway Construction Noise Model (RCNM),Version 1.1
---- Receptor #1 ----
Baselines (dBA)
Equipment
Results
Calculated (dBA)
1436
Report date: 8/4/2025
Case Description: Pacific Park Townhome Project
Description Land Use Daytime Evening Night
Site Preparation Residential 65 65 65
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Tractor No 100 84 250 0
Tractor No 100 84 250 0
Equipment *Lmax Leq
Tractor 70 70
Tractor 70 70
Total 70 73
*Calculated Lmax is the Loudest value.

Roadway Construction Noise Model (RCNM),Version 1.1
---- Receptor #1 ----
Baselines (dBA)
Equipment
Results
Calculated (dBA)
1437
Report date: 8/4/2025
Case Description: Pacific Park Townhome Project
Description Land Use Daytime Evening Night
Grading Residential 65 65 65
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Grader No 100 85 250 0
Tractor No 100 84 250 0
Calculated (dBA)
Equipment *Lmax Leq
Grader 71 71
Tractor 70 70
Total 71 73.6
*Calculated Lmax is the Loudest value.

Roadway Construction Noise Model (RCNM),Version 1.1
---- Receptor #1 ----
Baselines (dBA)
Equipment
Results
1438
Report date: 8/4/2025
Case Description: Pacific Park Townhome Project
Description Land Use Daytime Evening Night
Building Construction Residential 65 65 65
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Tractor No 100 84 250 0
Tractor No 100 84 250 0
Equipment *Lmax Leq
Tractor 70 70
Tractor 70 70
Total 70 73
*Calculated Lmax is the Loudest value.

Roadway Construction Noise Model (RCNM),Version 1.1
---- Receptor #1 ----
Baselines (dBA)
Equipment
Results
Calculated (dBA)
1439
Report date: 8/4/2025
Case Description: Pacific Park Townhome Project
Description Land Use Daytime Evening Night
Paving Residential 65 65 65
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Roller No 100 80 250 0
Roller No 100 80 250 0
Equipment *Lmax Leq
Roller 66 66
Roller 66 66
Total 66 69
*Calculated Lmax is the Loudest value.

Roadway Construction Noise Model (RCNM),Version 1.1
---- Receptor #1 ----
Baselines (dBA)
Equipment
Results
Calculated (dBA)
1440
Report date: 8/4/2025
Case Description: Pacific Park Townhome Project
Description Land Use Daytime Evening Night
Architectural Coating Residential 65 65 65
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Compressor (air) No 100 77.7 250 0
Equipment *Lmax Leq
Compressor (air) 63.7 63.7
Total 63.7 63.7
*Calculated Lmax is the Loudest value.

Roadway Construction Noise Model (RCNM),Version 1.1
---- Receptor #1 ----
Baselines (dBA)
Equipment
Results
Calculated (dBA)
1441
Project: Pacific Park Townhome Project Date: 8/8/2025
Activity: Construction Vibration JN: 2827-2025-02
Location: Nearest adjacent commercial structure Engineer: C. Stokes PPV = 0.062 in/sec
Equipment Type = 4 Loaded Trucks
PPVref = 0.076 Reference PPV at 25 ft.

D = 30.00 Distance from Equipment to receiver in ft.
n = 1.10 Vibration attenuation rate through the ground
Type
1 2
3 4
5 6
7 Crack and Seat 2.400
Loaded Trucks 0.076
Jackhammer 0.035
Small Bulldozer 0.003
Vibratory Roller 0.210
Large Bulldozer 0.089
Caisson Drilling 0.089
Vibration Impact Analysis
Vibration Input/Output Data
PPV = PPVref(25/D)n (in/sec)
Equipment PPV Reference Levels
Equipment Reference PPV
c:,
~ ENGINEERING GROUP INC.

I I
1442
Project: Pacific Park Townhome Project Date: 8/8/2025
Activity: Construction Vibration JN: 2827-2025-02
Location: Nearest adjacent commercial structure Engineer: C. Stokes PPV = 0.073 in/sec
Equipment Type = 2 Large Bulldozer
PPVref = 0.089 Reference PPV at 25 ft.

I I
1443
Project: Pacific Park Townhome Project Date: 8/8/2025
Activity: Construction Vibration JN: 2827-2025-02
Location: Nearest adjacent commercial structure Engineer: C. Stokes PPV = 0.172 in/sec
Equipment Type = 1 Vibratory Roller
PPVref = 0.210 Reference PPV at 25 ft.

D = 30.00 Distance from Equipment to receiver in ft.
n = 1.10 Vibration attenuation rate through the ground
Type
1 2
3 4
5 6
7 Vibratory Roller 0.210
Large Bulldozer 0.089
Small Bulldozer 0.003
Crack and Seat 2.400
Vibration Impact Analysis
Vibration Input/Output Data
PPV = PPVref(25/D)n (in/sec)
Equipment PPV Reference Levels
Caisson Drilling 0.089
Loaded Trucks 0.076
Jackhammer 0.035
Equipment Reference PPV
c:,
~ ENGINEERING GROUP INC.

I I
1444
Project: Pacific Park Townhome Project Date: 8/8/2025
Activity: Construction Vibration JN: 2827-2025-02
Location: Nearest adjacent residential structure Engineer: C. Stokes PPV = 0.062 in/sec
Equipment Type = 4 Loaded Trucks
PPVref = 0.076 Reference PPV at 25 ft.

I I
1445
Project: Pacific Park Townhome Project Date: 8/8/2025
Activity: Construction Vibration JN: 2827-2025-02
Location: Nearest adjacent residential structure Engineer: C. Stokes PPV = 0.073 in/sec
Equipment Type = 2 Large Bulldozer
PPVref = 0.089 Reference PPV at 25 ft.

I I
1446
Project: Pacific Park Townhome Project Date: 8/8/2025
Activity: Construction Vibration JN: 2827-2025-02
Location: Nearest adjacent residential structure Engineer: C. Stokes PPV = 0.172 in/sec
Equipment Type = 1 Vibratory Roller
PPVref = 0.210 Reference PPV at 25 ft.

I I
1447
Appendix J:

Pacific Park Drive Townhomes Project
Vehicle Miles Traveled (VMT) Screening Analysis,
City of Aliso Viejo
1448
NOVEMBER 24, 2025
Mr. Peter Carlson

CARLSON STRATEGIC LAND SOLUTIONS
27124A Paseo Espada, Suite 323
San Juan Capistrano, CA 92675
SUBJECT: PACIFIC PARK DRIVE TOWNHOMES PROJECT VEHICLE MILES TRAVELED (VMT)

SCREENING ANALYSIS, CITY OF ALISO VIEJO
Dear Mr. Carlson:

INTRODUCTION
RK ENGINEERING GROUP, INC. (RK) is pleased to provide this Vehicle Miles Traveled (VMT) Screening Analysis for the proposed Pacific Park Drive Townhomes Project (hereinafter referred to as “project”).

The purpose of this study is to utilize the City of Aliso Viejo Transportation Impact Guidelines for CEQA and General Plan Consistency, for determining VMT impacts under the California Environmental Quality Act (CEQA), to determine if the project will require a detailed VMT modeling analysis.

PROJECT DESCRIPTION
The proposed project site is generally located south of Pacific Park Drive, between Journey and Aliso Creek Road, in the City of Aliso Viejo. The project site is approximately 8.44 acres and is currently occupied by three (3) 2-story commercial office buildings totaling approximately 125,166 square feet, plus associated parking lots.

The proposed project consists of demolishing the existing commercial buildings and constructing 137 residential townhome dwelling units.

Primary access to the project is proposed to be provided via two (2) existing driveways. The first is a dedicated right-in/right-out driveway located along Pacific Park Drive, and the second is a shared fullaccess driveway located along Aliso Creek Road. The site can also be accessed via a third existing driveway located along Journey, however, only a small portion of project traffic is expected to utilize this driveway. None of the project entries are proposed to be gated.

The project is anticipated to open in 2027 and will be evaluated in one (1) single phase.

Exhibit A shows the location map of the project site. Exhibit B shows the proposed site plan.

ENGINEERING
GROUP INC.
1////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// rkengineer.com 1401 Dove Street I Suite 540 I Newport Beach, CA 92660 I 94 9.474.0809 1449

ENGINEERING
GROUP INC.

Exhibit A
Location Map
2827-2025-01

PACIFIC PARK DRIVE TOWNHOME PROJECT // CITY OF ALISO VIEJO Legend
= Project Site Boundary
N
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// 1450 ENGINEERING GROUP INC. Exhibit B Site Plan 2827-2025-01 PACIFIC PARK DRIVE TOWNHOME PROJECT// CITY OF ALISO VIEJO N ,-------------- 1 ///////////////// RI< I ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// 1451
RK21112 // 2827-2025-01 2

VEHICLE MILES TRAVELED (VMT) SCREENING
The City of Aliso Viejo Transportation Impact Guidelines for CEQA and General Plan Consistency provides recommendations in the form of thresholds of significance and methodologies for identifying VMT related impacts. The proposed project is subject to a VMT screening analysis and will adhere to the recommendations and practices described in the City’s guidelines.

The City of Aliso Viejo has developed three (3) types of screening criteria that can be applied to effectively screen projects from project-level assessment. The screening steps are identified below:
• Step 1: Transit Priority Area (TPA) Screening
• Step 2: Low VMT Area Screening
• Step 3: Project Type Screening
Step 1: Transit Priority Area (TPA) Screening
Based on the City of Aliso Viejo Transportation Impact Guidelines for CEQA and General Plan Consistency “Projects located within a TPA may be presumed to have a less than significant impact absent substantial evidence to the contrary.” However, this presumption may not be appropriate if the project:
• Has a Floor Area Ratio (FAR) of less than 0.75;
• Includes more parking for use by residents, customers, or employees of the project than required by the jurisdiction (if the jurisdiction requires the project to supply parking); • Is inconsistent with the applicable Sustainable Communities Strategy (as determined by the lead agency, with input from the Metropolitan Planning Organization); or • Replaces affordable residential units with a smaller number of moderate or high-income residential units.

A transit priority area is defined as a half mile area around an existing major transit stop or a highquality transit corridor. A major transit stop refers to a site containing an existing rail transit station, a ferry terminal served by either a bus or rail transit service, or the intersection of two or more major bus routes with a frequency service interval of 20 minutes or less during the morning and afternoon peak commute periods. A high-quality transit corridor refers to a corridor with fixed route bus service intervals no longer than 15 minutes during peak commute hours.

As indicated in the City’s VMT Guidelines, there are no TPA’s within Aliso Viejo. Therefore, the proposed project does not satisfy the screening criteria based on Step 1: Transit Priority Area (TPA) Screening.
,1//////////////////////////////////#/////////////////////////////////////////////////////////,W///////////////////////////////////////// ~ ~g/,'~~~ING rkengineer.com 1452
RK21112 // 2827-2025-01 3
Step 2: Low VMT Area Screening
Per the City of Aliso Viejo Guidelines, residential and office projects located within a low VMTgenerating area are presumed to have a less than significant impact absent substantial evidence to the contrary. To identify if the project is in a low VMT-generating area, Appendix A from the City’s VMT guidelines was used which provides a map showing the locations of low VMT-generating zones in Aliso Viejo.

As shown on Exhibit C, the proposed project is located in an area with a higher VMT per service population than city average (2045). Therefore, the proposed project does not satisfy the screening criteria based on Step 2: Low VMT Area Screening
Step 3: Low Project Type Screening
The City of Aliso Viejo Transportation Impact Guidelines for CEQA and General Plan Consistency specify that certain project types are eligible to screen from a project-level VMT assessment because they can be presumed to have a less than significant impact absent substantial evidence to the contrary as their uses are local serving in nature. These types of projects include:
• Local Serving Retail Less than 50,000 square feet (e.g., gas stations, banks, restaurants, shopping centers, etc.)
• Local-Serving K-12 schools
• Local parks
• Day Care Centers
• Local-serving hotels (e.g., non-destination hotels)
• Student housing projects on or adjacent to college campuses • Local-serving assembly uses (places of worship, community organizations) • Community institutions (Public libraries, fire stations, local government) • Local serving community colleges that are consistent with the assumptions noted in the

RTP/SCS
• Affordable or supportive housing
• Assisted Living Facilities
• Senior Housing (as defined by HUD)
• Projects generating less than 110 daily vehicle trips • Other local-serving projects as approved by the Planning Manager and Director of Community Development
The proposed project consists of razing the existing office building to construct 137 single-family attached residential dwelling units. As such, ITE Land Use Code 215: Single-Family Attached Housing ,1//////////////////////////////////#/////////////////////////////////////////////////////////,W///////////////////////////////////////// ~ ~g/,'~~~ING rkengineer.com 1453
2827-2025-01

PACIFIC PARK DRIVE TOWNHOME PROJECT // CITY OF ALISO VIEJO

ENGINEERING
GROUP INC.

Exhibit C
Low VMT-Generating Areas in Aliso Viejo
SITE
1,S1!i ·
iO 111 ~1511,; .
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// 1454 RK21112 // 2827-2025-01 4
and ITE Land Use Code 710: General Office Building trip rates accurately reflect the proposed and existing land uses, respectively.

The project proposes to demolish the existing 125,166 square feet of office and construct 137 residential townhome dwelling units. As such ITE Land Use: 215 Single-Family Attached Housing and ITE Land Use Code 710: General Office Building are the most appropriate trip rates to reflect the proposed and existing land uses, respectively.

It should be noted that for this CEQA Transportation Assessment, full trip credits for the existing entitled office buildings (utilizing ITE trip rates) have been utilized. Trip credits for an existing entitled use are based on the legal/entitled capacity of the site, not on its current level of activity or vacancy.

Even if an office building is temporarily vacant, the full trip credit still applies.

Table 1 shows the project trip generation rates and forecast for the CEQA Transportation Assessment with trip credits. The upper portion of Table 1 shows the trip generation rates utilized based on the ITE Trip Generation Manual (12th Edition, 2025) and the lower portion of Table 1 shows a comparison of the trips generated by the existing entitled land use to the trips generated by the proposed project.

Table 1 | Project Trip Generation Rates & Forecast1
For CEQA Transportation Assessment (With Existing Trip Credits) Land Use (ITE Code) Quantity Units2
Weekday
Daily AM Peak Hour PM Peak Hour
In Out Total In Out Total
ITE Trip Generation Rate
Single-Family Attached Housing (215) -- DU 25% 75% 0.47 57% 43% 0.51 6.57 General Office Building (710) -- TSF 88% 12% 1.24 16% 84% 1.18 7.83 Trip Generation Forecast
Proposed Project Trip Generation Forecast
Pacific Park Drive Townhomes (215) [A] 137 DU 16 48 64 40 30 70 900 Existing Entitled Land Use Trip Generation Forecast
Office Building (710) [B] 125.166 TSF 137 18 155 24 124 148 980 Total Net Trip Generation Forecast [A] – [B] -121 +30 -91 +16 -94 -78 -80 1 Source: ITE Trip Generation Manual (12th Edition, 2025). 2 TSF = 1,000 square feet
DU = Dwelling Units
As shown in Table 1, the proposed project is forecasted to generate approximately 80 fewer weekday daily trips. Therefore, the proposed project satisfies the screening criteria based on Step 3:

Project Type Screening and may be presumed to have less than significant impact on VMT under CEQA and no further VMT analysis is required.
,1//////////////////////////////////#/////////////////////////////////////////////////////////,W///////////////////////////////////////// ~ ~g/,'~~~ING rkengineer.com 1455
RK21112 // 2827-2025-01 5

CONCLUSIONS
RK Engineering Group, Inc. has completed this Trip Generation and Vehicle Miles Traveled (VMT) Screening Assessment for the proposed Pacific Park Drive Townhomes Project.

As specified in the City of Aliso Viejo Transportation Impact Guidelines for CEQA and General Plan Consistency, the proposed project is screened out from a full VMT analysis based on the Step 3:

Project Type Screening and may be presumed to have a less than significant impact on VMT under CEQA Therefore, no additional VMT analysis is required.

RK Engineering Group, Inc. appreciates this opportunity to work with the CARLSON STRATEGIC LAND SOLUTIONS on the Pacific Park Townhomes Project. If you have any questions regarding this review, or need further clarification, please contact us at (949) 474-0809.

Sincerely,
RK ENGINEERING GROUP, INC.

Justin Tucker, P.E., T.E. Bryant Medina
Principal Engineer I
Attachments
W/////////////////////////////////,-'/////////////////////////////////////////////////////////,1/////////////////////////////////////////// R1< I ~g',~~~ING rkengineer.com 1456
Appendix K:

Moulton Niguel Water District Engineering
Feasibility Letter
1457
February 5, 2025
Brandon Dieda [email protected]
RE: Proposed Development located at Aliso Creek Road 27231 Aliso Viejo- Shea Townhomes Dear Customer:

Moulton Niguel Water District (MNWD/District) has investigated the proposed development at the above referenced location. A Will Serve Letter will be sent to the City of Aliso Viejo, once Development plans have been reviewed and approved, and all required permitting steps are complete with MNWD Engineering. This letter is not to be interpreted as a District approval for a municipal Grading or Building permit.

Moulton Niguel Water District will service the above-mentioned project for water, recycled, and wastewater service, and preliminary review suggests available water supply and sewer capacity to support the project. This project is completely within MNWD's boundaries. As this project’s water use is expected to be less than the equivalent of 500 dwelling units, a Water Supply Assessment under Senate bill 610 is not required. The availability of water service is subject to the suppliers of water to Moulton Niguel Water District continuing to honor their contractual obligation relative to the amount of water to be supplied. Moulton Niguel Water District can make no representations as to the future intention of said suppliers in this regard. This indication of MNWD’s ability to serve the above-referenced project is conditional upon the following MNWD Permitting requirements:

Improvement Plans
Available capacity in the existing infrastructure will be determined once this development has received an Orange County Fire Authority (OCFA) Water Availability Form with required fire flows identified, and have this form submitted to the District for processing. This will be used to assess whether water system upgrades/upsizing is required. Water main upsizing and looping is anticipated for this location. Sewer main upsizing is not anticipated for this location.

Additional items required for submittal from the developer or project manager are:
• Will need to confirm via hydraulic modeling that fire flow demands will be met. • Any existing MNWD improvements not being used shall be demolished and removed.
• Each dwelling unit shall have its own independent water meter and fire sprinkler system. Developer shall reserve sufficient space to support the installation of meters and backflows.
• A new water main line connection at Pacific Park may be required to complete a sufficient water loop.
• MNWD will own and maintain a public sewer line in the major streets, but not within the alley ways in the proximity of the garages.

BOARD OF

DIRECTORS
Duane D. Cave

PRESIDENT
Richard Fiore

DIRECTOR
moulton niguel water district
Donald Froelich

DIRECTOR
Bill Moorhead

DIRECTOR
Brian S. Probolsky Diane Rifkin Sherry Wanninger

VICE PRESIDENT VICE PRESIDENT DIRECTOR
P.O. Box 30203 I Laguna Niguel, CA 92607 I 949. 831. 2500 I mnwd.com 1458 • Recycled water shall be required for irrigation over common HOA areas. Existing use sites at the project location shall be amended accordingly. • Completed Application for Water/Sewer Service
• Complete Insurance and Bonding Requirements per District requirements. • PDF plans showing locations of proposed potable water connections for domestic use and fire suppression, recycled water connections for dedicated irrigation use, wastewater connections, and grading over existing facilities.
• Engineer’s Estimate – materials and construction cost for facilities to be built and dedicated to the District. This will be used to determine Plancheck and Inspection fees, and used for construction performance bonding if required. • The fire suppression/sprinkler system water demand (gallons-per-minute calculation) from this project’s Fire Suppression/Sprinkler System designer. • Backflow installation on dedicated potable irrigation, homes with an ejector pump or subterranean plumbing, and irrigation services.
• Easement documents, and Title Report if applicable (if any facilities to be dedicated to the District will be located on private property). Easement Encroachment Agreement required if any surface improvements are proposed within the District easement. • PDF of Irrigation plans. The proposed project location is identified as Use Sites: D1511 and D1512.
• Completion of an OCFA Water Availability Form, and Proof of OCFA Review and Approval.
• Hydraulic Analysis for fireflow (while keeping pipeline flows under the maximum velocities allowed), and/or for wastewater flows (while keeping sewer pipeline capacities within allowable tolerances), to determine any required facility upsizing if required. • The use of recycled water will be required for construction. • All plan sets submitted to MNWD shall be in PDF format.

Fee Schedule
The fee schedule and applicable costs that may be required are as follows:
• Commercial, Residential, Irrigation
Meter Size Water Capacity Fee Wastewater Capacity Fee
¾” $2,405 $1,597
1” $2,405 $1,597

1.5” $4,810 $3,195
2” $7,695 $5,112

2.5” $12,265 $8,147
3” $16,834 $11,182
4” $30,301 $20,128
6” $67,335 $44,730
8” $115,432 $76,680
10” $182,767 $121,410
P.O. Box 30203 I Laguna Niguel, CA 92607 I 949. 831 . 2500 I mnwd.com 1459 • Potable Irrigation- Residential Development $1,479 per 1000 sq. ft. irrigated NonResidential Development $1,210 per 1000 sq, ft. irrigated • Plan check and Inspection Fees Minimum $800 plancheck and/or inspection; projects will require an initial deposit outlined in Resolution 18-13 • Construction Costs (both onsite and off-site improvements) • Reimbursement agreement fees, Developer Impact Fees, and/or Special Assessments, if applicable.

Fees are subject to change.

Record Drawings
As-Built Drawings of existing facilities will be provided once project design commences. Design Engineer or Project Manager may request these drawings on the District website, at https://mnwdca.seamlessdocs.com/f/requestdrawings.

MNWD will approve the plans after all remaining concerns have been addressed, easements are executed for facilities to be located on private property and after all applicable fees for this project are paid in full.

MNWD’s latest Standard Specifications are available online at: https://www.mnwd.com/wpcontent/uploads/Standard-Specifications-for-Construction-of-PW-RW-and-WW-Facilities-August2024-1.pdf MNWD’s latest Development Requirements are available online at: https://www.mnwd.com/wpcontent/uploads/2021/12/Complete-Doc-DEVELOPMENT-REQUIREMENTS-SIG-PAGE-PART-IAPENDICES-AND-PART-II-FINAL-2021.pdf If you have any questions or require further assistance, please do not hesitate in contacting Sheldon Yu ([email protected]) at your earliest convenience.

Regards,

MOULTON NIGUEL WATER DISTRICT
Mark H. Mountford, P.E.

Engineering Manager
P.O. Box 30203 I Laguna Niguel, CA 92607 I 949. 831. 2500 I mnwd.com 1460 Appendix L:

Fire Master Plan
1461
Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community Powered by Esri ALISO VIEJO FIRE ACCESS MASTER PLAN

PROJECT SITE

PACIFIC PARK DRIVE

ALISO VIEJO PARKWAY
ALISO CREEK ROAD CITY LIGHTS DRIVE CMMMB CM8/4/2025 N/A 7/30/2025 VICINITY MAP UPDATE D
m
m
ITT
m
N
ITT
N
0 N
' " ' 0

ORANGE COUNTY FIRE AUTHORITY

FIRE MASTER PLAN

VICINITY MAP OCFASTAMP
1------------------------------... -----------------------------------------------------------------------------------------------------------""'-------------------------------1~ W ~ V ~ ~ - ~

PRO JECT INFORMATION REQUIREMENTS
PROJECT LOCATION: 2718 1 Aliso Creek Rd
PARCEL MAP NUMBER: 632-124-0B
TRACT NUMBER:

LOT NUMBER:
0 EMERGENCY ACCESS EASEMENTS

DETAILED SCOPE OF WORK
NOTE: OCFA WILL ONLY REVIEW WORK OUTLINED IN SCOPE OF WORK Fire master plan of a residential townhome development and pool amenities with an accessory building.

NUMBER OF UNI TS OR HOMES IN DEVELOPMENT

SPECIAL CONDITIONS
0 FIRE HAZARD SEVERITY ZONE O STATE RESPONSE AREA O LOCAL RESPONSE AREA 0 STATE LICENSED FACILI TY
0 AM&M O PENDING O COMPLETE SR:
0 METHANE MITIGATION
NUMBER OF STORIES 3Stories
BUILDING HEIGHT MaximumHeioht 40' 11"
BUILDING AREA < 3,600sqft
OCCUPANCY TYPE (CHECK ALL THAT APPLY}
• INDICATES SFM REGULATED OCCUPANCY. OCFA PLAN SUBMITTAL REQUIRED # GROUP S MOTOR VEHICLE REPAIR AND AIRCRAFT REPAIR REQUIRE OCFA PLAN

SUBMITTAL
0 GROUP A 1' 0 GROUP A2' 0 GROUP A3• 0 GROUP A4• 0 GROUP 0 GROUP B 0 GROUP c• 0 GROUP Fl 0 GROUP F2 0 GROUP
0 GROUP H2• 0 GROUP H3• 0 GROUP H4• 0 GROUP HS' 0 GROUP 0 GROUP 12' 0 GROUP 13' 0 GROUP 14' 0 GROUP M 0 GROUP
0 GROUP R2• 0 GROUP R2.1 0 GROUP R2.2 ~ GROUP R3 0 GROUP 0 GROUP R4• 0 GROUP 51 # 0 GROUP S2# 0 GROUP u

TYPE OF CONSTRUCTION
0 TYPE IA O TYPE IB
0 TYPE IIA O TYPE 11 B
0 TYPE IIIA O TYPE II IB
0 TYPE IV
0 TYPE VA e TYPE VB
MIXED USE AN D OCCUPANCY (PER CBC 508 & 509)
0 ACCESSORY OCCUPA NCIES (CBC 508.2)
(ACCESSORY OCCUPANCY < 10% OF STORY)
O INCIDENTAL USES (CBC 509)
It NONSEPARATED OCCUPANCIES (CBC 508.3)
0 SEPARATED OCCU P ANCIES (CBC 508.4)

SPECIAL DE TAILED REQUIREMENTS
0 HIGH RISE (CBC 403)
0 ATRIUM (CBC 404)
0 OPEN PARKING GARAGE (CBC 4 06.5)
0 GROUP 12 (CBC 407) SMOKE COMPARTMENTS REFUGE AREAS
0 HAZARDOUS MATERIALS (CBC 4 14, CFC CHAPTER 50)

SPRINKLERS
• NEW O MANDATORY O VOLUN TARY
0 TENAN T IM P ROVEMENT
TYPE
0 NFPA 13
• NFPA 13D
0 NFPA 13R
0 FIRE PUMP
0 STANDPIPES

FIRE ALARM

O NEW O MANDATORY O VOLUNTARY
0 TENAN T IM PROVEM ENT
0 VOICE EVACUATION
FIRE FLOW REQUIREMEN T PER OCFA GUIDELINE B-01 A TTACHM ENT 23 FLOW (IN GPM @ 20 PSI): 1500 DURATION: 2

WATER AVAILIBI LI TY
A5•
Hl •
11'
Rl'
R3.1
*PROVIDE COPY OF OCFA WATER AVAILABILI TY FORM COMPLETED BY WATER DISTRIC T ON FIRE MASTER PLAN*
FLOW: 3895
PRESSURE: 121
~ ON SI TE FIRE HYDRAN TS
TOTAL NUM BER : 6

EMERGENCY RESPONDER RA DIO COVERAGR (BOA)

O THIS BUILDING SHALL BE EQU IPP ED WITH AN EMERGENCY RESPONDER DIGITAL RADIO SYSTEM PER THE REQUIREMEN TS OF m E ORANGE COUNTY SHERIFF'S DEPARTM ENT-COMMUNICATIONS & TECH NOLOGY DIVISION. FOR THE IN ITI AL SUBMITTAL. OCSD/COMM REQUIRES THE ERRCS/BDA/DAS SYSTEM DESIGNER TO PROVIDE THE FOLLOWING FOR PRE- EVALUATION: A. PROJECT NAME. B. SITE ADDRESS. C. PROJECT DESCRIP TION. D. CONTRACTOR CONTACT INFORMATION. E. BOA MODEL (S/N IF AVAI L ABLE). F . PROPOSED MODE OF OPERATION (CLASS A/B). G.

PROPOSED PROJECT TIM ELINE. THIS INFORMATION IS TO BE SUBMITTED BY TH E DESIGNER VIA EMAI L TO ERRCSOOCSD.ORG AND BDACERTOOCFA.ORG. CFC 510

OCFA STANDARD FIRE MASTER PLAN NOTES

INSPECTION REQUIREMEN TS

1. OCFA SITE INSPECTIONS ARE REQUIRED FOR THIS PROJECT. PLEASE SCHEDULE ALL FIELD INSPECTIONS AT LEAST 48 HOURS IN ADVANCE. INSPECTIONS CANCELED AFTER 1 P.M . ON THE DAY BEFORE THE SCHEDULED DATE WILL BE SUBJECT TO A RE-INSPECTION FEE. CALL OCFA INSPECTION SCHEDULING AT (714) 573-6150.

2. A LUMBER DROP INSPECTION SHALL BE PERFORMED PRIOR TO BRINGING COMBUSTIBLE MATERIALS (OR COMBUSTIBLE FIXTURES ANO FINISHES FOR STRUCTURES OF NON-COMBUSTIBLE CONSTRUCTION). ALL-WEATHER ACCESS ROADS CAPABLE OF SUPPORTING 94,000 LBS., TOPPED WITH ASPHALT, CONCRETE, OR EQUIVALENT SHALL BE IN PLACE AND HYDRANTS OPERATIONAL AT TIME OF LUMBER DROP INSPECTION. .3. FOR PROJECTS WITH FUEL MODIFICA1lON. A VEGETATION CLEARANCE INSPECTION IS REQUIRED PRIOR TO A LUMBER DROP INSPECTION. USE THE FUEL MODIFICATION PLAN SERVICE REQUEST NUMBER TO SCHEDULE THE VEGETATION CLEARANCE INSPECTION.

4. PHASED INSTALLATION OF FIRE ACCESS ROADS REQUIRES ADDITIONAL INSPECTIONS NOT COVERED BY THE FEES PAID AT PLAN SUBMITTAL. CONTACT INSPECTION SCHEDULING TO ARRANGE FOR ADDITIONAL INSPEC1lONS THAT MAY BE NEEDED AND ANY FEES THAT MAY BE DUE.

5. AN ORIGINAL APPROVED, SIGNED, WET- STAMPED OCFA FIRE MASTER PLAN SHALL BE AVAILABLE ON - SITE AT TIME OF INSPECTION.

6. ACCESS ROADS AND HYDRANTS SHALL BE MAINTAINED AND REMAIN CLEAR OF OBSTRUCTIONS AT ALL TIMES DURING AND AFTER CONSTRUCTION. AREAS WHERE PARKING IS NOT PERMITTED SHALL BE CLEARLY IDENTIFIED AT ALL TIMES. OBSTRUCTION OF FIRE LANES AND HYDRANTS MAY RESULT IN CANCELLATION OR SUSPENSION OF INSPECTIONS.

7. TEMPORARY FUEL TANKS OF 60 OR MORE GALLONS SHALL BE REVIEWED. INSPECTED, AND PERMITTED BY THE OCFA PRIOR TO USE.

8. THE PROJECT ADDRESS SHALL BE CLEARLY POSTED AND VISIBLE FROM THE PUBLIC ROAD DURING CONSTRUCTION.

9. ALL GATES IN CONSTRUCTION FENCING SHALL BE EQU IPPED WITH EITHER A KNOX OR BREAKAWAY PADLOCK.

10. BUILDINGS OF FOUR OR MORE STORIES SHALL BE PROVIDED WITH STAIRS AND A STANDPIPE BEFORE REACHING 40 FEET IN HEIGHT.

GENERAL REQUIREMENTS
11 . FIRE LANE WIDTHS SHALL BE MEASURED FROM TOP FACE OF THE CURB TO TOP FACE OF THE CURB FOR FIRE

LANES WITH STANDARD CURBS AND GU TTERS AND FROM FLOW-LINE TO FLOW-LINE FOR FIRE LANES WITH MODIFIED CURB DESIGNS (E.G. , ROLLED, RAMPED, ETC.). THE DEVELOPER IS RESPONSIBLE TO VERIFY THAT ALL

APPROVED PUBLIC WORKS OR GRADING DEPAR TMENT STREET IMPROVEMENT PLANS OR PRECISE GRADING

PLANS CONFORM TO THE MINIMUM STREET WIDTH MEASUREMEN TS PER THE APPROVED OCFA FIRE MASTER PLAN AND STANDARDS IDENTIFIED IN OCFA GUIDELINE 8-01 FOR ALL PORTIONS OF THE FIRE ACCESS ROADS.

12. PERMANENT, TEMPORARY, AND PHASED EMERGENCY ACCESS ROADS SHALL BE DESIGNED AND MAINTAINED TO SUPPORT AN IMPOSED LOAD OF 94,DOO LBS. AND SURFACED TO PROVIDE ALL-WEATHER DRIVING CAPABILITIES.

13. FIRE LANE SIGNS AND RED CURBS SHALL MEET THE SPECIFICATIONS SHOWN IN OCFA GUIDELINE B-01 AND SHALL BE INSTALLED AS DESCRIBED THEREIN. ADDITIONAL FIRE LANE MARKINGS MAY BE REQUIRED AT THE TIME OF INSPECTION DEPENDING ON FIELD CONDITIONS.

14. ALL FIRE HYDRAN TS SHALL HAVE A "BLUE REFLECTIVE PAVEMENT MARKER"" INDICATING THEIR LOCATION PER THE OCFA STANDARD. ON PRIVATE PROPERTY MARKERS ARE TO BE MAINTAINED IN GOOD CONDITION BY THE PROPERTY OWNER.

15. ADDRESS NUMBERS SHALL BE LOCATED AND BE OF A COLOR AND SIZE SO AS TO BE PLAINLY VISIBLE AN D

LEGIBLE FROM THE ROADWAY FROM WHICH THE BUILDING IS ADDRESSED IN ACCORDANCE WITH OCFA GUIDELINE B-01. WAYFINOING SIGNS, WHEN REQUIRED BY THE LOCAL AHJ, SHALL COMPLY WITH THE STANDARDS OF THAT AGEN CY. WHEN WAYFINDING SIGNS ARE ALSO REQUIRED BY THE DCFA, THEY MAY BE DESIGNED TO

LOCAL AHJ REQUIREMEN TS PROVIDED THA T SUCH STANDARDS FACILI TATE LOCATION OF STRUCTURES, SUITES, ANO DWELLING UNITS BY EMERGENCY PERSONNEL.

16. ACCESS GATES SHALL BE APPROVED PRIOR TD INSTALLA TION AND SHALL BE IN COMPLIANCE WITH CHAPTER 5 OF THE CFC AND OCF A GUIDELINES.

17. APPROVED ACCESS WALKWAYS SHALL BE PROVIDED TO ALL REQUIRED OPENINGS AND ALL RESCUE WINDOWS.

18. VEGETATION SHALL BE SELECTED ANO MAINTAIN ED IN SUCH A MANNER AS TO ALLOW IM MEDIATE ACCESS TO

ALL HYDRANTS, VALVES, FIRE DEPARTMENT CONNECTIONS, PULL STATIONS, EXTINGUISHERS, SPRINKLER RISERS,

ALARM CONTROL PANELS, RESCUE WINDOWS, AND OTHER DEVICES OR AREAS USED FOR FIREFIGHTING PURPOSES. VEGETATION OR BUILDING FEATURES SHALL NOT OBSTRUCT ADDRESS NUMBERS OR INHIBIT THE FUNCTIONING OF ALARM BELLS, HORNS, OR STROBES.

19. DUMPSTERS AND TRASH CONTAINERS LARGER THAN 1.5 CUBIC YARDS SHALL NOT BE STORED IN BUILDINGS OR PLACED WITHIN 5 FEET OF COMBUSTIBLE WALLS, OPENINGS OR COMBUSTIBLE ROOF EAVE LINES UNLESS PROTECTED BY AN APPROVED SPRINKLER SYSTEM.

20. ANY FUTURE MODIFICATION TO THE APPROVED FIRE MASTER PLAN OR APPROVED SITE PLAN, INCLUDING BUT NOT LIMITED TO ROAD WIDTH, GRADE, SPEED HUMPS, TURNING RADII. GATES OR OTHER OBSTRUCTIONS, SHALL REQUIRE REVIEW, INSPECTION. AND APPROVAL BY THE OCFA.

21. APPROVAL OF THIS PLAN SHALL NOT BE CONSTRUED AS APPROVAL OF ANY INFORMATION OR PROJECT CONDl1lONS OTHER THAN THOSE ITEMS AND REQUIREMENTS IDEN1lFIED IN OCFA GUIDELINE 8-01 AND RELATED PORTIONS OF THE 2022 CFC AND CBC. THIS PROJECT MAY BE SUBJECT TD ADDITIONAL REQUIREMENTS NOT

STATED HEREIN UPON EXAMINATION OF ACTUAL SITE AND PROJECT CONDITIONS OR DISCLOSURE OF ADDITIONAL INFORMATION .

PROJECT-SPECIFI C REQUIREMENTS

22. AN UNDERGROUND PIPING PLAN IS REQUIRED FOR THE INSTALLATION OF AN AUTOMATIC FIRE SPRINKLER SYSTEM OR FOR A PRIVATE FIRE HYDRANT SYSTEM. A SEPARATE PLAN SUBMITTAL 15 REQUIRED.

23. AN ARCHITECTURAL PLAN IS REQUIRED TO BE SUBMITTED TO THE OCFA FOR REVIEW AND APPROVAL FOR PROJEClS CON l AINING A, C, E, F, H, I, L, AND R-4 OCCUPANCIES. A PLAN MAY ALSO BE REQUIRED FOR R-1 AND R-2 OCCUPANCIES OVER TINO STORIES OR THOSE UTILIZING SPRINKLERS OR FIRE WALLS TO INCREASE THE MAXIMUM BUILDING SIZE ALLOWED--SEE OCFA INFO BULLETIN 02-13.

24. A CHEMICAL CLASSIFICATION AND HAZARDOUS MATERIALS COMPLIANCE PLAN SHALL BE APPROVED BY THE

OCFA PRIOR TO ANY HAZARDOUS MATERIALS BEING STORED OR USED ON SITE A SEPARATE PLAN SUBMITTAL IS REQUIRED.

25. BUILDINGS USED FOR HIGH-PILED STORAGE SHALL COMPLY WITH CFC REQUIREMENTS. A SEPARATE PLAN SUBMITTAL IS REQUIRED IF MATER IALS WILL BE STORED HIGHER THAN 12 FEET FOR LOWER- HAZARD

COMMODITIES, OR HIGHER THAN SIX FEET FOR HIGH-HAZARD COMMODITIES SUCH AS PLASTICS, RUBBER, FLAMMABLE/COMBUSTIBLE LIQUIDS, TIRES. CARPET, ETC.

26. AN AUTOMATIC FIRE SPRINKLER SYSTEM SHALL BE INSTALLED IN ACCORDANCE WITH APPLICABLE CODES AND LOCAL ORDINANCES, AMENDMENTS, AND GUIDELINES. SPRINKLER SYSTEMS, OTHER THAN THOSE LISTED IN CFC 903.4, SHALL BE MONITORED BY AN APPROVED CEN TRAL STATION. SEPARATE PLAN SUBMI TTAL$ FOR THE SPRINKLER AND MONITORING SYSTEMS ARE REQUIRED.

27. BUILDINGS CONTAINING INDUSTRIAL REFRIGERATION SYSTEMS SHALL COMPLY WITH CFC REQUIREMENTS. A SEPARATE PLAN SUBMITTAL IS REQUIRED IF REFRIGERANT QUANTI1lES EXCEED THRESHOLDS.

28. A FIRE ALARM SYSTEM SHALL BE INSTALLED IN ACCORDANCE WITH APPLICABLE CODES AND LOCAL ORDINANCES, AMENDMENTS, AND GUIDELINES. A SEPARATE PLAN SUBMITTAL IS REQUIRED.

29. STRUCTURES LOCATED IN A FIRE HAZARD SEVERITY ZONE OR WILDLAND - URBAN IN TERFACE AREA ARE SUBJECT TO THE CONSTRUCTION REQUIREMENTS PRESCRIBED IN CHAPTER 7A OF THE 2022 CBC AND/OR SECTION 337 OF THE 2022 CRC. CONSTRUCTION MATERIALS/METHODS ARE REVIEWED AND INSPECTED BY THE BUILDING DEPAR TMENT.

30. ONE OR MORE STRUCTURES SHOWN ON THIS PLAN ARE LOCATED ADJACENT TO A FUEL MODIFICATION AREA.

CHANGES TO THE FUEL MODIFlCATION ZONE LANDSCAPING, NEW STRUCTURES, OR ADDITlON/ALTERATION TO EXISTING STRUCTURES REQUIRES REVIEW AND APPROVAL BY THE OCFA.

31. PROJECTS LOCATED IN STATE RESPONSIBILITY AREAS AND IN LOCAL RESPONSIBILITY AREA VHFHSZ SHALL ALSO COMPLY WITH ALL APPLICABLE REQUIREMENTS FROM 1lTLE 14. DIV. 1.5. CH. 7, SUBCH. 2 "SRA FIRE SAFE REGULATIONS" AND GUIDELINE 8-0lA

32. STRUCTURES MEETING THE CRITERIA IN CFC 510.1 SHALL BE PROVIDED WITH AN EMERGENCY RESPONDER RADIO SYSTEM. REFER TO CFC 510.2 THROUGH 510.6,3 AND DAS/BOA GUIDELINES PUBLISHED BY QC SHERIFF'S COMMUNICATION AND TECHNOLOGY DIVISION FOR TECHNICAL AND SUBMITTAL INFORMATION.

GATES
0 MANUAL Q ELECTRIC

OCFA NOTES FOR ELECTRIC VEHICLE GATES

1. A REMOTE OPENING DEVICE IS REQUIRED. THE REMOTE GATE OPENING DEVICE THAT WILL BE INSTALLED IS (CHECK ONE),
0 3M OPTICOM
0 CLICK2ENTER* (SINGLE-PULSE MODE WITH 1.5 SECOND TRANSMISSION WINDOW) 0 FIRE STROBE ACCESS PRODUCTS, INC.
0 TOMAR

2. IN THE EVENT OF LOSS OF NORMAL POWER TO THE GATE OPERATING MECHANISM, IT SHALL BE

AUTOMATICALLY TRANSFERRED TO A FAIL- SAFE MODE ALLOWING THE GATE TO BE PUSHED OPEN BY A SINGLE FIREFIGHTER 'MTHOUT ANY OTHER AC1lON5, KNOWLEDGE, OR MANIPULATION OF THE OPERATING MECHANISM BEING NECESSARY.

A) A BATTERY MAY ONLY BE USED IN PLACE OF FAIL-SAFE MANUAL OPERATION WHEN THE GATE OPERATOR HAS A FAIL-OPEN MODE THAT WILL AUTOMA1lCALLY, IMMEDIATELY, AND COMPLETELY OPEN

THE GATE AND KEEP IT OPEN UPON REACHING A LOW POWER THRESHOLD, REGARDLESS OF THE

PRESENCE OF NORMAL POWER

B) SHOULD THE GATE BE TOO LARGE OR HEAVY FOR A SINGLE FIREFIGHTER TO OPEN MANUALLY, A

SECONDARY SOURCE OF RELIABLE POWER BY MEANS OF AN EMERGENCY GENERATOR OR A CAPACITOR WITH ENOUGH RESERVE TO AUTOMATICALLY. IMMEDIATELY, AND COMPLETELY OPEN THE GATE UPON LOSS OF PRIMARY POWER SHALL BE PROVIDED FOR FAIL-OPEN OPERATION.

3. IN ADDITION TO TI-ff REMOTE OPERATOR, THE GATE CONTROL SHALL BE OPERABLE BY A KNOX EMERGENCY OVERRIDE KEY SWITCH EQUIPPED WITH A DUST COVER. UPON ACTIVATION OF THE KEY SWITCH, THE GATE SHALL OPEN AND REMAIN OPEN UNTIL RETURNED TO NORMAL OPERATION BY MEANS OF THE KEY SWITCH.

WHERE A GATE CONSISTS OF TWO LEAVES. THE KEY SWITCH SHALL OPEN BOTH SIMULTANEOUSLY IF OPERATION OF A SINGLE LEAF ON THE INGRESS SIDE DOES NOT PROVIDE FOR THE WIDTH. TURNING RADII. OR SETBACKS NECESSARY FOR FIRE APPARATUS TO NAVIGATE THE VEHICLE ENTRY POINT.

4. THE KEY SWITCH SHALL BE PLACED BETWEEN 42"' AND 48" ABOVE THE ROADWAY SURFACE AT THE RIGHT SIDE OF THE ACCESS GATE WITHIN TWO FEET OF THE EDGE OF TH E ROADWAY. IN IRVIN E. THE SWITCH SHALL BE ON THE LEFT SIDE IN ACCORDANCE WITH IRVI NE'S UN IFORM SECURITY ORDINANCE.

5. THE KEY SWITCH SHALL BE READILY VISIBLE AND UNOBSTRUCTED FROM THE FIRE LANE LEADING TO THE CATE.

6. TH E KEY SWITCH SHALL BE LABELED WITH A PERMANENT RED SIGN WITH NOT LESS THAN ½" CONTRASTING LETTERS READING "FIRE DEPT" OR WITH A "KNOX" DECAL

STAKEHOLDERS
BUILD ING DEPARTMENT: CitvofAlisoVieio
PLANNING DEPARTMENT: Citv of Aliso Vieio
PUBLIC WORKS DEPAR TMEN T: CitvofAlisoVieio
WATER DISTR ICT: Moulton Niouel Water District
ALLOWABL E AREA FACTOR PER 2022 CBC TABLE 506.2:

Ao = ALLOWABLE AREA (SQUARE FEIT)
Al = TABULAR ALLOWABLE AREA FACTOR (NS, S1 JD, OR SM VALUE AS APPLICABLE) IN ACCORDANCE WITH TABLE 506.2
NS = TABULAR ALLOWABLE AREA FACTOR IN ACCORDANCE WITH TABLE 506.2 FDR A NON-SPRINKLERED BUILDING, REGARDLESS OF WHITHER THE BUILDING IS SPRINKLERED.

If = AREA FACTOR INCREASE DUE TO FRONTAGE (PERCENT) AS CALCULATED IN ACCORDANCE WITH SECTION 506.3

APPLICABLE CODES
e 2022 CALIFORNIA FIRE CODE
@I 2022 CALIFORNIA BUILDING CODE
• 2022 CALIFORNIA RESIDENTIAL CODE
• 2022 CALIFORNIA GREEN BUILDING STANDARDS CODE
• 2022 CALI FORNIA MECHANICAL CODE
e 2022 CALIFORNIA ELECTRICAL CODE
• 2022 CALIFORNIA PLUMBING CODE
• 2022 CALIFORNIA BU ILDING ENERGY EFFICIENCY STANDARDS • APPLICABLE NFPA STANDARDS
• LOCALLY ADOPTED ORDINANCES CITY:
• OCFA GUIDELI NES
• CONDITIONS OF APPROVAL CITY:

DEFERRED SUBMITTALS (CHECK ALL THAT APPLY)
THIS P ROJECT HAS BEEN PERM ITTED \NITHOUT REVIEW AND/OR APPROVAL OF THE FOLLOWING DEFERRED SUBMITTALS. PLANS APPROVED BY OCFA SHALL BE OBTAINED FOR

EACH DEFERRED ITEM LISTED BEL OW PRIOR TO COM MENCING ANY WORK WITHIN THE SCOPE OF SUCH DEFERRAL. DEFERRALS MUST BE REVI EWED AND ACCEPTED BY THE ARCHITECT OR ENGINEER OF RECORD PRIOR TO SUBM ITTING FOR REVIEW WITH OCFA.

POR TIONS OF THE PROJEC T mAT ARE DEFERRED SHALL BE SUBJECT TO THE CODES,

STANDARDS, AND OTHER APPLICABLE REQUI REMEN TS IN FORCE ON THE DATE THAT TH E DEFERRED PLAN IS SUBMITTED TO OCFA.
(ii ARCHITECTURAL PLAN

O HIGH P ILED COMBUSTIBLE STORAGE

O CHEMICAL USE AND/OR STORAGE
0 FUEL TANK (FOR GENERATOR, IF OVER 60 GALLONS)

O BATTERY /ENERGY STORAGE SYSTEM
0 UN DERGROUND SYSTEM SERVING SPRINK LERS, STANDPIPES, AND/OR

PRIVATE HYDRANTS
lit SPRINKLER SYSTEM
0 STANDPIPE SYSTEM
0 FIRE PUMP
0 HOOD AND DUCT EXTINGUISH ING SYSTEM

O ALARM SYSTEM

PREREQUISITE PLANS
0 PLANNING APPLICATION SR:
0 METHANE MITIGATION SR:
0 FUEL MODIFICATION PLAN SR:

REVISION
0 ORIGINAL PLAN SR:

COPY OF ORIGINAL APPROVED PLAN REQUIRED TO BE SUBMITTED WITH ALL REVISED PLANS.

REVISION SCOPE OF WORK

PROJECT DIRECTORY

ARCHITECT /ENGINEER
BU SIN ESS NAME: Woodlev Architectural Grouo. Inc
CONT ACT NAME: Mike Fuller -~~~~---------
ADDRESS: 2943 Pullman St. Suite A
CITY: Santa Ana STATE:~ZIP: 92705
----
PHON E: 949-553-8919
EMAI L: [email protected]
PROPERTY OWNER~HOA
BUSINESS NAME: = hcecaaHsom= es~----------
CONTACT NAME: miie imar ,==----------- ADDRESS: 2 Ada Suite 200 CITY: Irvine STATE:

PHON E: 949-526 8800
ZIP: ___ _
EMAIL: emU1e.s1mard(dlsheahomes.com
TENANT
BUSINESS NAME: ___________ _
CONTACT NAME: _____________ _
ADDRESS: _____________ _
CITY: ________ STATE: ZIP: ___ _
PHON E: ____ _
EMAIL: __________ _
0 w
z
a
a
w
0 z
0 <
"
D
~ z
0 w
u,
C,
;t
0 0
u,
z
0 >'
0 w
~
0 w
rr
C,
0 w
rr
u,
z "
w
0 5
z
<{
w
"' "
w
5 w
rr
<{
<{
~
0 0
0 z ~
0 0 D
~
Ill
C
::::,
C
z
0 >-
0 w
~
u,
z
r
~ 0
z z
0 <{
" " w w
> 5
w w
rr rr
z z
5 5 ~ ~
□ D
SHEET 1
1462
1"=100' @ 24X36 2
SR #
SHEET OF 5
SERVICE REQUEST NUMBERORANGE COUNTY FIRE AUTHORITY COMMUNITY RISK REDUCTION - PLANNING AND DEVELOPMENT SECTION OCFA REVIEW AND INSPECTIONS (OCFA USE ONLY) NO OCFA REVIEW REQUIRED PLAN REVIEW ONLY PLAN REVIEW AND INSPECTION DESIGNED: DRAWN: CHECKED: DATE: SCALE: 7654321NO. DATE REVISIONS ALISO VIEJO FIRE ACCESS MASTER PLAN CMMMB CM8/4/2025

PROJECT VICINITY MAP
Existing Fire Hydrant Locations

FIRE MASTER PLAN SUBMITTAL CHECKLIST
350-FOOT BUFFER

FROM SITE
LEGEND

1. TYPES OF OCCUPANCY THAT WILL BE HOUSED IN

THE STRUCTURES AS LISTED IN CALIFORNIA
BUILDING CODE (CBC) 2022 EDITION: R-3, U.

2. CONSTRUCTION TYPE: VB.

3. BUILDING HEIGHT: MAXIMUM BUILDING HEIGHT OF
40'-11".

BUILDING DATA

1. EXISTING LAND USE: COMMERCIAL (EX. PROFESSIONAL
OFFICE).

2. PROPOSED LAND USE: PROP: 137 ATTACHED RESIDENTIAL
CONDOMINIUM DWELLING UNITS.

3. EXISTING ZONING: PROFESSIONAL OFFICE.

4. WATER SERVICE PROVIDED BY: MOULTON NIGUEL WATER
DISTRICT.

5. SANITARY SEWER SERVICE PROVIDED BY: MOULTON NIGUEL
WATER DISTRICT.

6. ELECTRIC SERVICE PROVIDED BY: SOUTHERN CALIFORNIA
EDISON COMPANY.

7. GAS SERVICE PROVIDED BY: SOUTHERN CALIFORNIA GAS
COMPANY.

8. APN# 632-124 (8.44 ACRES)

GENERAL NOTES

OCFA WATER AVAILABILITY FORM JOURNEY ALISO CREEK ROAD
PACIFIC PARK DRIVE CITY LIGHTS DRIVE 7/30/2025 PROJECT VICINITY MAP UPDATE 8/4/2025 FMP SUBMITTAL CHECKLIST UPDATE .Q,
.,
5 0
en
<(
.,
E
0 I
0 .,
.c
Vl
" <D
,n
a:,
~ ~
en
.,
L
0 L..

I:
0 ..0
L
::,
a "' ?-
en
~
u
.'!1,
0 L
()._
/
0 ~
0 ~ ~
I:
.,,
.,
-0
:,
-0
-:;
Guideline B-01 January 01 , 2023

ATTACHMENTS
Attachment 1 - Fire Master Plan Submittal Checklist

PROJECT INFORMATION
Scope of project is clearly defined on the plan?
Conditional Use Permit conditions included with submittal? Tract/Tentative TracUParcel Map Number has been provided? Standard OCFA fire master plan notes are included?
i,ZI Yes
D Yes D N/A (CUP was not required by city/county)
i,ZI Yes
Building area, construction, occupancy, sprinkler type noted on plan? Allowable area calculation provided on plan?
QI Yes (Notes are tailored to this project, where applicable) i,ZI Yes
D Yes D No (<6,000 sf unsprinklered; <18,000 w/ sprink.) Sheets not relevant to fire master plan removed from plan set? i;z1 Yes Access/hydrant phasing plan provided?

WATER AND HYDRANTS
Water avai lability form completed and provided?
All hydrants within 350' of the site are shown on plan? Are hydrants provided/spaced per Gu
ideline B-01 , Attachment 3?

ACCESS AND ROADWAYS
Extent of the access roadway is clearly shown on the plan? Turning radii and width (incl. road sections) shown on the plan? Exterior of all structures within 150' hose pull distance? Engineer's certification provided for new paving?
Walkable suriace provided to required openings?
Road and walkway grades >10% shown on plan?

FIRE LANE IDENTIFICATION
Red curbs are identified on plan with bold . dashed, or red lines? Location of each "Fire Lane-No Parking" sign shown?
Fire lane entrance sign provided at each vehicle entrance? Drawings of red curbs/"No Parking"/entrance
signs provided?

GATES AND OBSTRUCTIONS
Are all gates, fences, and planters shown?
Are vehicle gates identified as manual or electric?
Gate operator specs showing emergency operation provided? Manual vehicle gates have "No Parking" sign noted?
Knox boxes/locks/switches are noted on plans?
OCFA gate notes/specifications included on plan?

OTHER REQUIREMENTS
AM&M request letter scanned onto plan?
Premises ID/address monument location shown on plan?
Trash enclosures are located at least 5' from buildings? Two entry points provided for 150 or more residences?
Buildings > 75' to highest occupiable floor called out? Parking enforcement letter provided?
Project located in methane zone(s) (portions of Yorba Linda, Buena Park.

Seal Beach, San Clemente, and Unincorporated Orange County)? 24 D Yes ~ N/A (No phasing of access/hydrant installation) ~ Yes D No (in progress) D No (no change in demand)
6Z1 Yes
[;z1 Yes
[;z1 Yes
i,ZI Yes
i,ZI Yes D No (AM&M proposed) D No (sprinklered R-3)
i;z'.I Yes D N/A (No new paving) 0 Yes
D Yes i,11 NIA (Grade <10%)
i;z'.I Yes D N/A ("Fire Lane-No Parking" signs provided) i;z'.I Yes D N/A (Red curbs provided)
l;z1 Yes D N/A (All roads at least 36 feet wide)
l;z1 Yes D N/A (All roads at least 36 feet wide)
i,ZI Yes
D Yes [;z1 NIA (No gates proposed)
D Yes ~ N/A (No electric gates proposed)
D Yes g NIA (No manual gates proposed)
D Yes IZ'l NIA (No gates proposed)
D Yes i,11 NIA (No gates proposed)
D Yes &'.'.l N/A (No alternate methods proposed)
l;zl Yes D N/A (Single family homes)
QI Yes D No (Enclosures are existing or sprinklered)
i;2I Yes D N/A (Non-residential project)
D Yes [Y1 N/A (No high-rise structures)
D Yes D N/A (Public streets only)
D Yes EZI No
NOTE: This is only a listing of basic fire master plan submittal requirements Other information or requirements may be necessary,
depending on conditions specific to each project

OCF A WATER AVAILABILITY FORM
SECTION A: To be completed by customer
Project Name: Shea Homes - Aliso Viejo OCFASR#: ASS
IGNED UPON Pu\"J SUBMITTAL
Project Address: 27181 Aliso Creek Rd
Applicant Phone #: ('-_8_58_~)._3'-5'-3--5'-8-'0"'2 _______ _ City: Aliso Viejo
Fax#:

Area of largest building 5800 ft'; Construction type? (check one) 0GJI 11All~ll111Allmsll:2JI vAII q Is this building sprinklered throughout? (check one) 0 ~ SECTION B: To be completed by local water department/district Customer to provide results to OCFA
Water Department/District: Moulton Niguel Water District Test location (indicate address or cross-streets & provide reference map): 27181 Aliso Creek Rd, Aliso Viejo CA Hydrant number(s) (if applicable): _F_H_D_16_0_3_6 ______________________ _ Elevation of test hydrant: ___ 3_6_2_' __________________ feet above sea level pateofTest1: 6/12/2025 Timeoftest
1:
laml lrml
Test to be performed as close as possible to the lime that the lowest flows and pressures are expected (e.g., M-F, 6:00 - 9:00 am and 5:00- 9:00 pm)

FLOW TEST RES UL TS
TEST INFORMATION IS VALID FOR 6 MONTHS FROM DATE TESTIS PERFORMED Static pressure: 121 psi Residual pressure: 104
Observed flow: 3,895 gpm Flow calc'd at 20 psi: See Note [x] Check the box if the test information above was obtained in a manner other than an actual flow test (i.e. by computer modeling) Note: Flow at 20 PSI exceeds District velocity criteria; flow beyond 3,895 GPM exceeds District velocity psi
gpm
Based on fluctuations known to exist at the site of the test, provide estimated values for the following:

Maximum static pressure I psi Minimum static pressure I psi Minimum residual pressure I psi Minimum residual flow I gpm I have witnessed and/or reviewed this water flow information and by personal knowledge and/or on-site observation certify that the above information is correct.

Name: Sean Phayakapong Company/Agency: Moulton Niguel Water District Signature: / G / Title: _S_r_._G_I_S_A_n_a_ly~s_t ________ _ Date: 6/12/2~252}
--------------------
Revised 117116 ese
•
----
---
I
I
• I
\~=,t:: I
I
I
'~ fl~
1 ~lilll!IIIIIII~ ~lllllllil~
~ ~llllllillllilll· ~IIIIIIUII~ ~
•
\
'
'
-<~
;\ II
sc:,c .•• ,..,
" .
•
□ □ □
240
I

SCALE IN FEET
1463
1 2
2 2 2
2 2 2
2 2 2
2 2
2 2
2 2
2 2
2 2
2 2
2 2
2 2 2
2 2
2 2
2 2 2 2 2 2 2 2
2 2
2 2
2 2
2 2 2
2 2
2 2 2
2 2
2 2 2
2 2 2
2 1
2 2
2 2
2 2 2 2 2
2 2 2 2 2
2 2 2 2 2 2 2 2
2 1
2 INSTALL "FIRE LANE ENTRANCE SIGN" PER DETAIL H ON SHEET 5 INSTALL "FIRE LANE SIGN" PER DETAIL I ON SHEET 5
INSTALL "FIRE LANE SIGN (WALL MOUNTED)" PER DETAIL I ON SHEET 5 RED CURB, SEE DETAIL E ON SHEET 4
LEGEND
R=20'
R=40'

FIRE LANE TURNING
RADIUS

FIRE HOSE PULL

FIRE ENGINE

PROPOSED FIRE HYDRANT
INSTALL "ADDRESS MONUMENT" PER OCFA GUIDELINE B-09
FIRE LANE ACCESS - POTENTIAL FOR PARKING ON ONE SIDE, 30 FT WIDE FIRE LANE ACCESS - THRU ACCESS / LOOPED, 25 FT WIDE
FIRE LANE ACCESS - DEAD END, 23 FT WIDE 2 AS SHOWN
3 SR #
SHEET OF 5
SERVICE REQUEST NUMBERORANGE COUNTY FIRE AUTHORITY COMMUNITY RISK REDUCTION - PLANNING AND DEVELOPMENT SECTION OCFA REVIEW AND INSPECTIONS (OCFA USE ONLY) NO OCFA REVIEW REQUIRED PLAN REVIEW ONLY PLAN REVIEW AND INSPECTION DESIGNED: DRAWN: CHECKED: DATE: SCALE:
7654321NO. DATE REVISIONS ALISO VIEJO FIRE ACCESS MASTER PLAN CMMMB CM8/4/2025

FIRE ACCESS PLAN ALISO CREEK ROAD
PACIFIC PARK DRIVE 8/4/2025 FIRE ACCESS PLAN UPDATE
SEE PAGE 6: "FIRE LADDERING ANGLE
ANALYSIS - EAST TOWNHOUSE"
SEE PAGE 6: "FIRE LADDERING ANGLE
ANALYSIS - WEST TOWNHOUSE"
10/4/2025 2: 20: 41 AM \ \dudek.int\data\Projects\320.UrbanForestry\18567 Shea Home Aliso Viejo DDAFMP\03 GIS_Graphics\FMP\Alisa Viejo FMP 20250714 I '~
l- y
X
I
U)
(")
)>
r
01 z
;;i
01 ---i
0 0 "'
~o,
0 \
' ' J
T
i
T
?
-
...
u, ------11 : 5-' - - .. '---'--'.J -1=
-~
'
__,.
•
D
.ri. iL I fl,,
•
.. I
-
~r J
t;; h .___,
J
-
i
L =.
"-
..
"'
-
J
j tr·
7 ~-
1-, .r.

L I
rr
~1
-I _Lt')
.I
,/ /
.//
/ .
-
__,.
•
•
.
,;1 • ill ~ ,;' 1---1~
~111 I t ...
,...
[ ? 1 ~ --~
·~ \~ 1ll[j ,_
oll 1
0 f
-
"-
..
18 ""
..
- I II~
>~I~ G l
-- '~In
•
II,..
-
I
0 -1 1 I
,...
r·-
-
-
-
"" ..
l
I
h
__,.
•
El
•
•
J Ji
r;
"'"
V
IK\\I I 11 I
' " \\
·, ' \
\\ ·, \. \
I I I
I
I
I
IJ
I I
,,
,,
,,,
I
11 ' I
\,
'\
~,
11 o·
- I
t El
sl[ ?
1~
:
--
-
I 11 -
0 ~I
1r ?
Ir ,f~
e;f f
I I •
I I
H !
105'
I) r-ri.... _ __. e:---.l.-,--- i[:-•.J. __ __, 1 oo·
"L i 11
11 .. r
r j o;I
1 I I
I..
_
W
jl
I
-
' [~:: ••• _ --,,,
'· ... ··' \
,..'',
/ ·., /// ·• ' J I I
I ·-.
0~ 1
,j I I
..
~ I
H; I
f
JI
::\\
,_ '
-
J .........
,_
• •
t &
gi, , ::i(I
1r ? --~
0 ~,\
--~ <\
lh •
1~~t __ I r \\
.

I
•
•
ft) '
r
I
...
~-
-
,..
..

I§
11 l!ji f----r-
'11
J
.,
I
!
1 J 1' t: I
,...
0 ....., r
•
f-----i j
t '
t--- ._ ___ , - r-
~" ..
0 -
~-
:::::( ::::/ :::>,
-
17 6 \\ ..... L......,--,l
p
~ !
-
....... . ____.. ,~
r
• •
L
..
----"I I' -
7 t
.
i
I
..

J J
f.
[
J.
~ IL"' J:]~
·----
~;;
f~Jt;
r- II---"
g
I
oll L
0 f
I
I r
I D
- .
f
llJI • _j i L., r" ~ i I IIi =::::!.'"t-; . I ~r----f.1..,,1,=-, \ ...

I I l r ~\ ,-
-
qo j Ii
1:::::
air , L sl1' , t ,...
... '\ G J
1r ?
N
0 ,_
I i
I
\
·\
-..
-
• •
-
., I 11--,.

I P. ~11 • r
I
,~ ,~
•
•
a J
di~ ~I b L 11
~Jr 5 =
...

I[ ?
1~ CD 0
I ... ~\
,... ? " 111,
,~ ;}¾Jf \
~rim
rr- ~ ...
\ .
\ \, 0
0 - •

1.1- I I µ .,_
f- l
I - 100'
'- 120'
-~
'tj---
,_ '11 l I I \
Q . 0 t?%11i1
- •
... • ...
...r, LI- I I I --f
~ \ ,I
~.b==,a,,!I~ 1-
120'
PLANS PREPARED BY:

DUDEK
605 Third Street Encinitas, CA 92024
760.942.5147 Fax 760,942.9976
120·
1-L
,_ \
105'
105'
I i o II I '- f ,
ll
1464

AS SHOWN
4 SR #
SHEET OF 5
SERVICE REQUEST NUMBERORANGE COUNTY FIRE AUTHORITY COMMUNITY RISK REDUCTION - PLANNING AND DEVELOPMENT SECTION OCFA REVIEW AND INSPECTIONS (OCFA USE ONLY) NO OCFA REVIEW REQUIRED PLAN REVIEW ONLY PLAN REVIEW AND INSPECTION DESIGNED: DRAWN: CHECKED: DATE: SCALE:
7654321NO. DATE REVISIONS ALISO VIEJO FIRE ACCESS MASTER PLAN CMMMB CM8/4/2025 2 SEE SHEET 5

FIRE LANE WIDTHS AFIRE LANE S-CURVES BTURN-AROUND DIMENSIONS C

FIRE HYDRANT MARKER LOCATIONS DRED CURB MARKINGS ELADDER PAD F ALL DETAILS FROM OCFA GUIDELINE B-01
"FIRE MASTER PLANS FOR COMMERCIAL AND
RESIDENTIAL DEVELOPMENT"
-
" 0
IO
N
0 N
a.
::,;
Ii.
.Q_
Q)
5 0
rn
<(
/
a.
~ rn
.,!
.c
a.
0 L
'-'1
(/)
(!)
"' 0
/
a.
::,;
Ii.
<(
0 0
,Q_
Q)
5 0
rn
<(
Q)
E
0 :r:
0 Q)
.c
(/)
" <D
IO
IXl
< L
-rn
Q)
L
0 Ii.

C
0 -e
:::,
0 N
,.
rn
-u
.!!!,
e
[]._
/
0 -0
";!,
-C
.:,,
Q)
" ::,
;;
::;
<(
..-
"' 0
N
N
IO
N
0 ~ 0
®

FIRE LANE
20' minimum
ROADWAY LESS THAN 28'
Parl.i11g pro/1ibited.

Roadtray is required 10 be posted as afire la11e.
®

PARKING
8' minimum
ROADWAY AT LEAST 28' BUT LESS THAN 36'
Parking permitted on one side only.

Roadway is required to be posted as s fire lane.

PARKING
8' mlnlmum

FIRE LANE
20i m1nlmum
ROADWAY 36' OR WIDER
Pm-kl11x pem,irred 011 boil, sides
Figure 1-
Minimum Road
Widths

PARKING
81 mfnlmum
Figure 15 - "Blue Dot" Reflective Hydrant Marker Location TWO LANE STREET MUL Tl-LANE STREET
□ □

INTERSECTION INTERSECTION WITH TURN
_J □ L _J □ L □
7 _ .I

MULTILANE STREET WITH TURN LANE FREEWAYS AND EXPRESSWAYS □
I
Figure 2 - ''S'' Turns
40'
i
20'
____ _l 60'
4!0'
Drawings not to scale, for illustration purposes only.

NOT PERMITTED PERMITTED
Figure 4 - Fire Lane Identification, Red Curbs

STANDARD CURB ROLLED CURB
• Curbs shall be painted OSHA safety red.

NO CURB/

FLARED CURB
• "FIRE LANE - NO PARKING" shall be painted on /QQ of curb in 3" white lettering at a spacing of 30' on center or portion thereof
T
20'
_J_
20'
20'
T
29'
25'
t
20'
40'
25•-· I L ...______.
20'
..---50 ---,,,. 20 ,.l ---50'---..

Figure 17 - Ladder Pad Setback at Rescue Openings
Rescue windows are required ro optm
directly lo a p11blic street, public alley,
yard, or exir court.
h
~d 3•+ 1 (h/5)+2 • d Laddering
Pad
Dz+3'
Overa II width of pad is
Laddering Pad from D, to a point 3'
behind D,
□ □ □
1465

2.50' BUILDING SETBACK FROM THRU ACCESS FIRE 2.50' BUILDING SETBACK FROM THRU ACCESS FIRE LANE LANE AS SHOWN 5 SR #
SHEET OF 5
SERVICE REQUEST NUMBERORANGE COUNTY FIRE AUTHORITY COMMUNITY RISK REDUCTION - PLANNING AND DEVELOPMENT SECTION OCFA REVIEW AND INSPECTIONS (OCFA USE ONLY) NO OCFA REVIEW REQUIRED PLAN REVIEW ONLY PLAN REVIEW AND INSPECTION DESIGNED: DRAWN: CHECKED: DATE: SCALE:
7654321NO. DATE REVISIONS ALISO VIEJO FIRE ACCESS MASTER PLAN CMMMB CM8/4/2025

FIRE LANE SIGN LOCATIONS GFIRE LANE ENTRY SIGN HFIRE LANE SIGN I

TOW COMPANY INFORMATION SIGN JFIRE LANE SIGN MOUNTING K DETAILS G-K FROM OCFA GUIDELINE B-01
"FIRE MASTER PLANS FOR COMMERCIAL AND
RESIDENTIAL DEVELOPMENT"

BUILDING TO FIRE LANE SETBACK L
sj-
-r--
0 "' N
0 N
Q_
:::.

LL
.Q,
.,
>
0 Ill
5-
Q_
:::.
> Ill
u
.c
Q_
0 L
Cl
I
Cf)
Cl
,,.,
;;,
Q_
:::.

LL
<(
0 0
.Q,
.,
>
0 Ill
<(
.,
E
0 I
0 .,
.c
Cf)
r--
"' "' 00
< L
-Ill
:ii
0 LL
C
0 ..c
L
::::,
0 N
?-
Ill
-u
.!!I.,
0 L
~ 0
-0
-c:,
./
-C
-"'-
.,
-c:,
::,
;::
::!'
<(
sj- "' 0
N
N
"' N
0 ~ v
'--
Figure 12 - Fire Lane No Parking Sign Locations
SO'max.--►
50'
- -
_ Fire Lane Sign
• (post mounted)
Figure 7 - Alternate Location of
Towing Company Information
NOTICE
0 NO PARKING IN

AREAS MARKED AS

VIOLATING VEHICLES

WILL BE CITED

OR TOWED AT
0WNER'SOEXPENSE
Fire lane entrance
sign shall meet al I
OCFA standards
detailed in this
guideline
LAW AGENCY NAME & PHONE#
eve 22658(a) eve 22soo.1

TOWING COMPANY NAME
0 TOWING COMPANY PHONE#
0 ~
Minimum 1" red
lettering on white
reflective
background
-
Figure 6 - Fire Lane Entrance Signs
1J
NOTICE

NO PARIKING IIN

AREAS MARKED AS

FIRE LANE

VIOLATING VEHICLES

WILL BE CITED
OR TOWED Al

OWN ER'S EXPENSE
LAW AGENCY NAME & PHONE #
TOWING COMPANY NAME & PHONE#
r 1-3/8" bold red
lettering on white
reflective
background
1- - 2-3/4" bold White
reflective lette~ing
ori red backgro,und
1-3/8" bold red
lettering on white
reflective
background
eve 22658(a) eve 22soo.1 '---- 1" red lettering on
Fire Lane Sign
(wall mounted)
Figure 13- Mounting Specifications for Fire Lane Entrance and No Parking Signs

NO PARKING IN AREAS
I.IARKEDAS

FIRE LANE
VIOU,.TIM (l VEIICl.£S
ll'l l1-BE£11ED
OR lll'ft'ED /IT
ow,mn EYJ'EN SE
LAYrA""rt::l""""E • FtlOOE
• ~C'l\'ING co..,,ANr NM<E.

PHO ....
eve Zlt>B:!!f:::CV~ :z:l!<Kl.1
NOTICE

NO PARKING IN AREAS
~1ARKEDAS

FIRE LANE
\'IOU.TING l'EHICLES
l\'lll_BE-C IIED

OR TOWED AT

OWNER'S E)'J'ENSE
LAYf-rt::r ..,,..,E. Ft<l»<E
• TC"l<JNG CO MPANr NM<E 0
Pll<l ....

CVC22ti5"<- CV~:z:'l:,Ql;l.1
Pedestrian areas: 7'
All other areas: 5'
Pedestrian areas: 7'
All other areas: 5'
118" -
24"
' i~ l-,/,,i~ ~~
L.t:.:.~ '

STANDARD CURB
-- 2 4" ----
Concrete footing or
other approved means
of stabilization
24"

ROLLED CURB
white reflecbive
background
• I □• • II ~ i II I
I! !
I'
Figure 5 - Fire Lane No Parking Signs
18"
□

FIRE LANE
NO

PARKING

VIOLATING VEHICLES

WILL BE CITED

ORTOWEDAT

OWNER'S EXPENSE
CVC22500.1
eve 22658(a)
f----·
I
I
!
'
"-2" bold, condensed
white reflective
lettering on red
background
~ 2" bold, condensed
red lettering on
white reflective
background
1" red lettering on
white reflective
background
O~------

S CALE IN FEET
0 6 9 12
□ □ □
~ iu, a, ,._
a,
W t5~
-.... ~ a,
C ~g
·u ..... ;.: C M
., '-" C
-~ iii ~
::, ~!;;;:
~ "' - UJ "' "E "' il: ·- ....

C .ca,
"' ,- d
~ "' "' 0 ,._
"'
~ L--------------------------------------------------------------------------------------------------------------- 1466 13'-7"
23'-10"
73°
73° 4'-0"6'-10" 3'-2" LADDER PAD
6'-0"

FENCE LINE

SILL HEIGHT

SILL HEIGHT
4'-6" ADJACENT PROPERTY
13'-7"
23'-10"
73°

SILL HEIGHT

SILL HEIGHT
4'-6" ADJACENT PROPERTY
73° 4'-0"6'-10" 22'-2" FIRE ACCESS ROAD - 25 FT WIDE SR # SHEET OF 5 SERVICE REQUEST NUMBERORANGE COUNTY FIRE AUTHORITY

COMMUNITY RISK REDUCTION - PLANNING AND DEVELOPMENT SECTION

OCFA REVIEW AND INSPECTIONS (OCFA USE ONLY)

NO OCFA REVIEW REQUIRED

PLAN REVIEW ONLY

PLAN REVIEW AND INSPECTION
DESIGNED:

DRAWN:

CHECKED:

DATE:

SCALE:
7 6
5 4
3 2
1 NO. DATE REVISIONS

ALISO VIEJO FIRE ACCESS MASTER PLAN
CM
MMB
CM
8/4/2025 FIRE LADDERING ANGLE ANALYSIS - WEST TOWNHOUSE

B FIRE LADDERING ANGLE ANALYSIS - EAST TOWNHOUSE
A
6 1D/4/2O25 2: 20: 12 AM \ \dudek.int\data\Projects\32O.UrbanForestry\18567 Shea Home Aliso Viejo DDAFMP\O3 GIS_Graphics\FMP\Alisa Viejo FMP 20250714 0 (fl
)>
"
r
r'l
"' .-, z
.,,
r'l
r'l
;-J ' ' -<
"'
~
0 '!: I l.,1 1\171 ''I/:
r ',~fl•-··
./ l~ l .. ~ ,f, _r,11-:"'j . • FJ:,.
' if 1:1:"lii,:.;, .' J ,\~(,~,,,,!Y"l'
11 l''~L. :1:, l"jl .\_t_ 1,u_,.1:·' I •• , r I•~ ' 1 ' ~ 'I! '
,' ·.'. l,ftt ,;',~-I l"tt.' , 1f '\ti lll(,11/J ,\"\~ ,,j\' -~~f /i)~:~~J·/\f'l:,·..,., · ;-,-,- ~r,...,... il""" }'.. 1rn,,:,] f '(:, ,,~,:,J•, ,:r1h ;J't
I 'J_:v ,ll:1_ It_'.1\111 ,\p 1
1 ~1••_1,_·•~.~I- ~\11:. '.i~hlllti•1~:J 1i1;,'}1;,r: Jll'.i f •':;lit,:,;J,'~ \)f \'~';,;J'l i;;!tl\;.Y'J
I
1 11714i_ L l,, ii,. 1 ·il._ t~,-iti]i.°f'll'll_'
, 'fr ·1·, ... ··1- -~-. ·•w••fh ,1,· ·, •1r.. _ 1 ,it r •.. i' 1 __ ,;·r1rt\ 1Y.,_ ,, ,. ;)· J · 'f 1'' . • , fi·'I ~ ~- -1 f 1:l•i,:11 ·11 ,,",,i,,;, :t i\i~:F:l'f
I
1 ·71.- -~ll)1 11·'f_,~·-'i)l',jlfi_-~_'. •-- U\)1: , t _ r ?i', 1·.: 1ir~.r ;c •. '.t'r1;11i: 1 1{}}'
'I· 1 ... 'I fii·•I. 'f i· l'W.t:
'fli/i;, jl~{~•,;j 't\:n,1,,;-].1
I 11:1, ~ ~L), ,l~I 1't•
l,1 ·'·. ,; t HI li.1 'f I • J. .} ! l'l ' • '- i ~-- j -~( P)lt\ \\;I-~ J .i:
, .. i1 ... :H /t -~; •<ih 't,::1/ f 1::, ltl1,1l/J ,, ,,,,:,,:l,-''l; ~; !.['' :1:l,J , Ii ~ \ J_,)i F}1 "j 1 ".;I
··t•i,: __ .r_·.-_,r '?l ·1·•. •1~_,·r,,i1rs1l/'.,, , _l,1i~, J~. It!_, ~!,·li;_, 'r~f1~1.'J,n)f !\~;,,~,.,,~):.f :a:f { • - '
/ ,!-. Lt - • 1\, [ l)i • ,, l u1 :n_r41_ ,·: i1_7111~• t 1•:,1t"'' •• " ''\l ''I '~ "W ,It 'J J II± , 1 1
'-;:i' 11 _,• •:,.·1e __ ;'!r1,.::J'"11f.i i I i i
,,;,~1r1~:t1~1~:::1:11:·1·1:1·r,j !!I 11111111 l
1 I 11111111 1! 1 I I 11
, I I 1 l1
f / 1'k ,J1' • 1""1"' -,,, • ~ 1p ,LJ I 1\._,I ~ ,
'• '• II I --------
PLANS PREPARED BY:

DUDEK
605 Third Street Encinitas, CA 92024
760.942.5147 Fax 760.942.9976
0 U>-.""I
;-J '
"'
0 □
□
□
'
(fl
)>
"
r
r'l
z
.,,
r'l
r'l
-<
,' I~.,! .·/ ·~. ;' ~-' J lf 11
J ;-\~"11 '': ,.,, \~,,:,. ~
' Ii' 1\!"' t'.)•I ?ii ,' I ~1, 1 1 ' '
, - -, I' ,, -. I ' ·, J. , ; ' :, r,·, M' .i : r . ' '• - '_"·1. ·-"~--. '_'._-'j •'_·j' '_•·i· .. •-... ,1·1 ) - ,_ ,_J·•ir,.~· !,.:· -.

I ,!1 \~:,,J' f- '\, \~'\ l _'.;, i~' ,;
' I'' l_\ ·"'_ ,_1_.~_/; ,1 __ 1_ 1.i-' 'l' .,., 1 1 i'-._,_ '.-~\ '• • _'1!. 'j~ ',,~••·1- '· ':··, ,lh ·,, • I ' i'. I ' ,l ' I t ~ . ,:J•!j ., ~,• J,t:,, .. J' "t "' I.,,,.,_,.~\). 1,,,·,,tl" 1, i.•.,,
' I" 1··;-41:(1~,1 1i ,IJ:h'l\1: ,,_~· ·•;-_ilP~\· . ·1·· ,, ')•! ' J' ••.•. ,_,r·,·,.~1•1, ·1 ·r· ~-' '.- ••fr·•·.- ir_· ,i •~--tP,·-1
~ , -':/..'•'· ~ ·. {, 1.-:.~· ' '·1 'i ,l(f - t , .. I, (,!,,f_ - ' ·I ~.,.Y. f ,, I I l,• Y:

I ,lt1 '\, ])\ ' L ]_~'J, "1 •L ], 1 .bl_ ,hJ_~ 1 -.lnl ' ,' ;'i\ _,; '._J,., ,1 "'I \ 'I:'_ 1_,,., -~',_ • .,. __ I ,l_ I { dl;\llr __ ''t\_ 'J>j .'_f ,,~_ '_:', :Ir 1
.'-·1 l ~f; , ~--1 ' ~f 1 . f I J 1'' ~ !t,l,.',\Vt~ ,,.,,:,:!•J ,".n ,, ,, -,], I 41Ll~I 11itln l}-1·~,',p l' ''"'';•_!r(,it,_A_lk'-•r ',1'_.·i_·, ,_1.f ,,,_, J,,j_~J,, w- ~.-~' .{ ,lg ,, 1 q,!,,;l :, •71; 1 ,,, .• 1. 1 , -.-0 1, L,J. '.~Lll. l.
1 ,1 71 '.;l I ~1• ,, t'\!l Jl , ,·,t1•111,1.~' 't"l '.j·_- r,l' ·_;' /_I· ;~! , ~- I ( , ,~ I ; , r. ~1- 1·i ,,, •. ·11 S!:[1 ~,1.
!1 .. -[':'l'•.'·1 -~...; 1,'"•'l; -l' •11 ,- ·'1
• lnJ l
1 .. · •, h ll]' · 1h. \!ip_ , ·, 1 •1.i'll,11'' ·., :'J I.''!''. , ' " 1··1r{'~, /~1~i~: , Xtk:'.r J
,R4 f, 1,,,:.i~ ~, 1~
• 1:1 )1 \!~, l_\ ~,1'j 11
• ' 1 7l' 1 I 1 1 • HP~ Ir' c•1 J /-,.-i,lt! h., 1-~~ I ~ 1
' '), '."i..r- 1 i_~1;,,·. /
\, • 111 ' L! 7 J '' fH ) ' 11' 7 j 'it I j ~-,·,, I I :
0 • ., .. • •• 1• , ·f ,;\'·, ■ ..._ I ■ I
.,.. _•l""l ,• l:'l 'i _r:i'''. , ~, ,f ~ ',,~11,1,!;,11•:, IY'\1.,,;;1 I f •n H--1 \\,,' n. 1\, ·11 . ., , L,11 "'iv,,., L:ll' I [OJ
1467
Aliso Creek Residential Development Project
Draft IS/MND Response to Comments
July 21, 2026
Letter No. 1 – Caltrans (July 8, 2026)
1-1 The comment is introductory and does not provide specic comments on the environmental analysis. The comment is noted.
1-2 The comment states there is link between transportation and land use and Caltrans supports collaborating with local agencies. The comment does not provide specic comments on the environmental analysis. The comment is noted. 1-3 The comment indicates that improving access to multimodal transportation (i.e. walking, biking, and transit) can reduce greenhouse gas emissions (GHG) and vehicle miles traveled (VMT). The comment does not provide specic comments on the environmental analysis. It should be noted that the Project provides walking trails and sidewalks through the community and connects to existing sidewalks. Furthermore, the Project reduces VMT compared to the existing office land use.
1-4 The comment suggests providing secure short-term bike parking within the Project. The Project is a residential community where each dwelling unit has its own garage with space for bicycle parking. Furthermore, bicycle parking is provided at the recreation center for community use. Therefore, the design of the community incorporates facilities for bicycle parking.
1-5 The comment requests incorporating high visibility crosswalks and ADA curb ramps. Internal to the Project, the low volume and low speed internal streets do not warrant high visibility crosswalks. External to the Project site, no analysis has shown that the Project would generate the need for high visibility crosswalks at existing intersections adjacent to the Project site. Crosswalks currently exist at surrounding intersections within public right-of-way. The City could upgrade those crosswalks through a capital improvement project, however there is no evidence of nexus to the Project to upgrade crosswalks. 1-6 The comment requests that future residents and workers of the development use transit. This request is noted, but controlling human behavior is beyond the 1468
control of the development project. The Project has been designed as inll, near existing commercial and recreational uses. Furthermore, compared to existing office use, the Project would reduce trip generation and VMT. 1-7 The comment requests “a discussion on existing bus route services and future transit improvement opportunities including intercounty and regional connectivity.” The IS/MND provides a discussion on existing bus routes in Section

5.17 on Page 93. The information provided references bus routes 177 and 90.

Based on comments received from OCTA, the discussion includes the following edits.

Transit Facilities
Public transportation services within the Project site and surrounding area are provided by Orange County Transportation Authority (OCTA). The primary OCTA bus routes serving the Project area are Routes 177 and 90.

Route 177 provides service between Foothill Ranch Mission Viejo and Laguna Hills, traveling via Alicia Parkway with key stops serving the Aliso Viejo Town Center to the north of the Project across Pacic Park. Route 90 connects Tustin to Dana Point, passing through Aliso Viejo along Aliso Creek Road Moulton Parkway. There are no existing or planned transit facilities adjacent to the Project site. Project implementation would not conict with a program plan, ordinance, or policy addressing transit facilities.

The comment also requests information on future transit improvement opportunities. Details of future transit improvement opportunities are beyond the scope of the IS/MND and more appropriately provided by the transit operator, such as OCTA, Metrolink, etc.
1-8 The comment suggests providing waynding signage to nearby transit services within the Project. The Project is not large enough and existing transit is not located close enough to the Project site to warrant waynding signs. Those who are interested in using transit would do so intentionally and would not need to rely on waynding to reach transit, unlike a larger project site with multiple transit options where waynding would facilitate the use of transit. 1-9 The comment suggests that internal streets and driveways are wide enough for truck turning movements. The Project has been designed to accommodate 1469
trucks, including trash and re truck, turning movements, which has been conrmed through City plan check.
1-10 The comment encourages the inclusion of shared package drop-off areas. The Project is not large enough or contain high enough density housing to warrant shared package drop-off areas.
1-11 The comment requests detours, signage, and safety measures be incorporated into the construction phase. The comment is noted. The majority of construction work would occur on the Project site and not interrupt vehicle, pedestrian, or bicycle traffic. Where utility connections are required, the Project would be required to obtain an encroachment permit from the City, which requires detour and traffic control plans to ensure vehicle, pedestrian, and bicycle safety. 1-12 The comment describes Caltrans requirements for construction haul activities.

The comment is noted. All construction truck loads and deliveries are subject to vehicle code requirements.
1-13 The comment states that construction-related traffic must not adversely impact operations on the State Highway System. The Project site is not located adjacent to the State Highway System, and no improvements would be made to the State Highway System. Therefore, construction of the Project would not cause a direct adverse impact on the State Highway System.

Letter No. 2 – OCTA (July 8, 2026)
2-1 The comment provides corrections to bus Route 177 and Route 90. The corrections have been incorporated into the following edits found on Page 93 of the Draft IS/MND. The edits provide correction of information only and do not change the analysis or conclusions presented in the Draft IS/MND.

Route 177 provides service between Foothill Ranch Mission Viejo and Laguna Hills, traveling via Alicia Parkway with key stops serving the Aliso Viejo Town Center to the north of the Project across Pacic Park. Route 90 1470
connects Tustin to Dana Point, passing through Aliso Viejo along Aliso Creek Road Moulton Parkway. There are no existing or planned transit facilities adjacent to the Project site. Project implementation would not conict with a program plan, ordinance, or policy addressing transit facilities.

Letter No. 3 – Orange County Fire Authority (July 14, 2026) 3-1 The comment is introductory and does not provide specic comments on the environmental analysis. The comment is noted.
3-2 The comment is introductory and does not provide specic comments on the environmental analysis. The comment is noted.
3-3 The comment states that after review of the Project the Commentor has concluded the Project would have a less than signicant impact associated with re protection. The comment is noted.
1471

"
#$%$$%$"$&

)*
+,(#-$.'(

)*
+,(

/

01122
1

,

,
1

3
4+"

(

526 -

071 8$

4

((&

4:$
;
<
,=$,

(,*((

3

4

*">5!2+

$
;
<"$&
(
(

526 "

?4:

:

:

'

)

@:
5

%

:
$

><
:
4:$
;
<2

:

2
<

*
,

4@

2
<

@ ::

4
"

,4@@
'
@

,4B

'(
@

*'
*)2

4
<

:

?A
@

:

::

:

2

"

:

::
A

A
: 2

A
@

@?@:
"
:

"

"
,

?
:
"
A

' 2
2 @
?

"A ?

"

)2>

C

"

A

A4

B'B9B)

"

"
;

';5)2

1472

!
!

"
#$%!

!
(

')

)
$*!
(

')

)

! '

!

'

! '

+"
,
,

!

-
$$

!

$.$/!!

0 ')

')

)

!

'

,
!
')

-
$$
')
')
,!

$.$

23

')

)

!

!
4

5)

)
"

-
)

637
!
700,,,$'$
0'

.$

+$

!

!!

'

, )

6
'

)

'!$

8$

,
)

!
9

: $

&

'

$
%!

5
;
<==5
;
>

?
@
09

9

)*
$

$

:
,

,!
!

,
$

,
)$

=$

!

!

)

$

$4

!

!

)

(

-
$$

)

!!(

$

1473

"
"

#
$%&
!

!
"

'
"
( !!

! (!!

)% !

!"

"
*
+",*

(

%

"

!

!

-

.

,"!"

'
/

*
"",
,

!

'

!1

(

/

"
!

!

%

!
!1

" (
!

%

))%2"

!
"

"!

!/

"
*
+",*

%

!!

,"

!

"",

"",

" !
,""

!

"

3 4
2
!
&

5
342&6

%2"

!
"

"
( !

(

!

!%

!
!

,"

"%
7 %!%
%

*!

*!*"

8 !""
9! &

,/
"

&

!)
;<=>>;?@AA@BCDEAFGHIHJKJLMNLOHPQRS
1474

AFFILIATED AGENCIES

Orange County
Transit District
Local Transportation
Authority
Service Authority for
Freeway Emergencies
Consolidated
Transportation
Service Agency
Congestion Management
Agency

Orange County Transportation Authority
550 South Main Street / P.O Box 14184 / Orange / California 92863-1584 / (714) 560-OCTA (6282) July 8, 2026
Ms. So Kim
Director of Community Development
City of Aliso Viejo
12 Journey, Suite 100
Aliso Viejo, CA 92656
Via Email: [email protected]
Subject: Aliso Creek Residential Development Project Initial Study/Mitigated Negative Declaration (No. CEQA-2026-01000) Dear Ms. Kim:

Thank you for providing the Orange County Transportation Authority with the opportunity to review the Initial Study/Mitigated Negative Declaration (IS/MND) for the Aliso Creek Residential Development Project. The following comments are provided for your consideration:
• On Page 93 of the IS/MND, under ‘Transit Facilities’, please revise the transit service descriptions as follows:
o Change "Route 177 provides service between Foothill Ranch and Laguna Hills" to "Route 177 provides service between Mission Viejo and Laguna Hills."
o Change "Route 90 connects Tustin to Dana Point, passing through Aliso Viejo along Aliso Creek Road" to "Route 90 connects Tustin to Dana Point, passing through Aliso Viejo along Moulton." Thank you for the opportunity to review this document. Should you have any questions or comments, please contact me at (714) 560-5907 or at [email protected].

Sincerely,
Dan Phu
Director, Transportation Planning and Analysis
DP:pv
1475

O R A N G E C O U N T Y F I R E A U T H O R I T Y
P. O. Box 57115, Irvine, CA 92619-7115 • 1 Fire Authority Road, Irvine, CA 92602-0125 TJ McGovern, Fire Chief (714) 573-6000 www.ocfa.org
Serving the Cities of: Aliso Viejo • Buena Park • Cypress • Dana Point • Garden Grove • Irvine • Laguna Hills • Laguna Niguel • Laguna Woods Lake Forest • La Palma • Los Alamitos • Mission Viejo • Rancho Santa Margarita •San Clemente • San Juan Capistrano • Santa Ana Seal Beach • Stanton • Tustin • Villa Park • Westminster • Yorba Linda • and Unincorporated Areas of Orange County

RESIDENTIAL SPRINKLERS AND SMOKE ALARMS SAVE LIVES
July 14th, 2026 (SR 26003300)
So Kim, Community Development Director
Aliso Viejo
[email protected]
Subject: Aliso Creek Residential Development Project
Dear So,
Thank you for the opportunity to review the subject document. The Orange County Fire Authority (OCFA) provides fire protection and emergency medical services response to 23 cities in Orange County and all unincorporated areas. The OCFA operates 78 fire stations throughout Orange County.

Per Ttile14 CCR § 15164 Would the project result in substantial adverse physical impacts associated with the provision of new or physically altered governmental facilities, need for new or physically altered governmental facilities, the construction of which could cause significant environmental impacts, in order to maintain acceptable service ratios, response times or other performance objectives for any of the public services:

We believe that the project will have less than a significant impact.

Please contact me at 714-573-6102 if you have any questions.

Sincerely.

Todd Letterman
Assistant Fire Marshal
Planning and Development
[email protected]
www.ocfa.org
1476

Page 1 of 7 ends

Aliso Viejo City CouncilOctober 21, 2026

Aliso Viejo City Council
October 21, 2026