N:\3709 - Pico Apts\Report\Updated Memo.3709.doc
Boulevard, it is built as a 6-lane divided roadway. The posted speed limit is 45 mph.
On-street parking is prohibited. Curb, gutter and sidewalks are provided on both sides of the roadway. Class II bike lanes are provided east of Pico Avenue.
San Marcos Boulevard
San Marcos Boulevard is currently constructed as a 4-lane divided roadway. The posted speed limit is 40 mph. On-street parking is prohibited. Sidewalks are provided on both sides of the roadway. Class II bike lanes are provided.
Figure 2 depicts the Existing conditions.
B. EXISTING TRAFFIC VOLUMES
Peak hour intersection turning movement volume counts were conducted on Thursday, January 12, 2023, and 24-hour segment volumes counts were conducted at Thursday, January 26, 2023, when schools were in session.
Figure 3 contains the Existing traffic volumes. Attachment A contains the fieldwork count sheets. Table 1 summarizes the existing segment volumes.
TABLE 1
EXISTING SEGMENT VOLUMES
Street Segment Existing a
Mission Road
Knoll Road to Pico Avenue 14,510
San Marcos Boulevard
Pico Avenue to Twin Oaks Valley Road 5.860
Pico Avenue
Mission Road to San Marcos Boulevard 31,200
Footnotes:
a. Counts conducted on January 26, 2023.
Mr. Ryan Binns
February 3, 2023
N:\3709 - Pico Apts\Report\Updated Memo.3709.doc
C. VMT ASSESSMENT
The regional VMT per capita is 18.9. Per the City’s Transportation Impact Analysis Guidelines (November 16, 2020), the Project would not have a significant VMT impact if VMT per capita for the Project is below the threshold of 85% of the regional VMT per Capita, or 16.1 VMT per capita.
Using the SANDAG screening map for residential projects under VMT per capita, the Project would be expected to generate 11.9 VMT/capita for census tract 200.28. The Project’s VMT per capita is below the threshold and hence the Project is presumed to have less than significant VMT impact.
Table 2 shows the VMT analysis results. Attachment B includes the result of the SANDAG screening map.
TABLE 2
PROJECT VEHICLE MILES TRAVELED ANALYSIS
Geography VMT per Capita
San Diego Region 18.9
Significance Threshold (85% of the San Diego regional Average) 16.1 Project Site - Pico Avenue Apartments 11.9
Exceeds Threshold? No
D. PROJECT TRIP GENERATION AND ASSIGNMENT
The Project trip generation calculations were conducted using the trip generation rates published in SANDAG’s (Not So) Brief Guide of Vehicular Traffic Generation Rates for San Diego Region (April 2002). Based on the project description, the condominium category was used which SANDAG specifies as 8 trips / unit.
Table 3 summarizes the Project trip generation calculations. As shown in Table 3, the proposed Project is calculated to generate 128 daily trips with 10 AM peak hour trips (2 inbound / 8 outbound) and 13 PM peak hour trips (9 inbound / 4 outbound).
The Project traffic was distributed and assigned along Mission Road and San Marcos Boulevard based on the site location, access to SR78, existing traffic patterns in the area and anticipated traffic patterns to and from the site. Based on the above, 25% Mr. Ryan Binns
February 3, 2023
N:\3709 - Pico Apts\Report\Updated Memo.3709.doc
were assumed to be oriented to the north of the Project site and 75% were assumed to be oriented to the south of the Project site.
Table 4 summarizes the Existing + Project segment volumes. Figure 4 depicts the Project traffic distribution and Figure 5 depicts the Project traffic volumes and Figure 6 contains the Existing + Project traffic volumes.
TABLE 4
EXISTING + PROJECT SEGMENT VOLUMES
Street Segment Existing Existing + Project
Mission Road
Knoll Road to Pico Avenue 14,510 14,536
San Marcos Boulevard
Pico Avenue to Twin Oaks Valley Road 5.860 5,956
Pico Avenue
Mission Road to San Marcos Boulevard 31,200 31,277
E. PROJECT ACCESS ASSESSMENT
Table 5 summarizes the Existing and Existing + Project intersection operations. As shown in Table 5, with the addition of Project traffic volumes, both Project driveways are calculated to operate at LOS B.
Attachment C contains the Existing and Existing + Project intersection analysis worksheets.
Mr. Ryan Binns
February 3, 2023 Page 5 N:\3709 - Pico Apts\Report\Updated Memo.3709.doc TABLE 3
TRIP GENERATION SUMMARY
Land Use Size Daily Trip Ends (ADTs) AM Peak Hour PM Peak Hour Rate a Volume % of
ADT
In:Out
Split a
Volume % of
ADT
In:Out
Split a
Volume
In Out Total In Out Total
Multifamily Attached Units 16 dwelling units 8 / DUb 128 8% 20:80 2 8 10 10% 70:30 9 4 13 Footnotes: a. Rates are based on SANDAG’s (Not So) Brief Guide of Vehicular Traffic Generation Rates for the San Diego Region, April 2002. b. Rates are based on condominium rate of 8 / DU.
Mr. Ryan Binns
February 3, 2023
N:\3709 - Pico Apts\Report\Updated Memo.3709.doc
TABLE 5
EXISTING + PROJECT INTERSECTION OPERATIONS
Intersection Control
Type
Peak
Hour
Existing Existing + Project
Delaya LOSb Delay LOS
1. Pico Ave / Project North Dwy DNE c
AM – – 10.1 B
PM – – 11.1 B
2. Pico Ave / Project South Dwy / San
Marcos Unified School District Dwy
TWSCd AM 11.3 B 11.4 B
PM 14.2 B 14.5 B
Footnotes:
a. Average delay expressed in seconds per vehicle
b. Level of Service
c. This driveway does currently exist and will be built by the Project as a TWSC intersection. d. TWSC – Two-Way Stop Controlled intersection. Worst-case movement approach delay and LOS reported.
General Notes:
DNE – does not exist.
UNSIGNALIZED
Delay LOS
0.0 ≤ 10.0 A
10.1 to 15.0 B
15.1 to 25.0 C
25.1 to 35.0 D
35.1 to 50.0 E
≥ 50.1 F
A. CONCLUSIONS
Based on the analysis conducted for the Project, no CEQA VMT impacts were calculated. No Project-induced deficiencies were calculated at the Project access driveways and no improvements are necessary to accommodate Project traffic.
Please let us know if you have any questions. Thank you.
Sincerely,
Linscott, Law & Greenspan, Engineers
John Boarman, P. E. Narasimha Prasad
Principal Senior Transportation Engineer
cc: File
Mr. Ryan Binns
February 3, 2023
N:\3709 - Pico Apts\Report\Updated Memo.3709.doc
FIGURES
Figure 1: Project Site Plan
Figure 2: Existing Conditions Diagram
Figure 3: Existing Traffic Volumes
Figure 4: Project Traffic Distribution
Figure 5: Project Traffic Volumes
Figure 6: Existing + Project Traffic Volumes
TABLES
Table 1: Existing Segment Volumes
Table 2: VMT Analysis Results
Table 3: Project Trip Generation
Table 4: Existing + Project Segment Volumes
Table 5: Existing + Project Intersection Operations
ATTACHMENTS
Attachment A: Fieldwork count sheets
Attachment B: SANDAG screening map
Attachment C: Existing and Existing + Project intersection analysis worksheets LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-22-3709 Pico Avenue Apartments
N:\3709 - Pico Apts\Report\Attachments.3709.doc
ATTACHMENT A
FIELDWORK COUNT SHEETS
Pico Avenue Apartments
Date: 12‐Jan‐23
Day: Thursday
Pear Hour: AM
Time
Left Right Left Through Right Through
7:30 0 0 6 33 7 24
7:45 0 0 6 56 17 35
8:00 2 1 6 54 10 34
8:15 3 3 3 47 4 37
Total 5 4 21 190 38 130
Pear Hour: PM
4:30 8 1 1 41 3 52
4:45 8 1 0 51 0 48
5:00 6 0 0 82 0 59
5:15 3 1 0 49 0 45
Total 25 3 1 223 3 204
WB
Traffic Counts
School District Driveway Pico Avenue
SB NB
Location: BC 23-006 #01 East Mission Road between Knoll Road & Pico Avenue Date: Thursday, January 26, 2023 Total Daily Volume: Description: Total Volume 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 42 28 19 44 75 193 444 973 1108 580 525 540 631 737 934 1727 1782 1870 969 465 352 272 118 84 12 7 6 7 10 27 62 165 304 173 130 133 124 167 157 345 454 472 333 131 94 83 39 32 14 9 4 10 14 32 107 193 319 137 129 130 154 203 199 418 443 457 285 88 84 75 26 18 5 5 5 10 22 54 104 295 249 123 134 130 181 191 273 494 422 467 185 119 100 57 25 25 11 7 4 17 29 80 171 320 236 147 132 147 172 176 305 470 463 474 166 127 74 57 28 9 Date: Thursday, January 26, 2023 Total Daily Volume: Description: Eastbound Volume 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 25 15 9 19 31 82 165 425 456 260 256 278 308 387 587 1160 1230 1264 634 265 210 158 75 57 6 5 2 4 5 10 29 71 139 72 63 68 59 80 86 261 322 329 229 76 52 53 24 19 9 5 3 5 6 13 37 80 121 63 65 57 79 108 100 302 307 309 197 48 52 41 18 15 4 3 3 4 6 22 38 126 100 51 66 70 91 98 195 316 279 302 116 67 55 31 17 18 6 2 1 6 14 37 61 148 96 74 62 83 79 101 206 281 322 324 92 74 51 33 16 5 Date: Thursday, January 26, 2023 Total Daily Volume: Description: Westbound Volume 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 17 13 10 25 44 111 279 548 652 320 269 262 323 350 347 567 552 606 335 200 142 114 43 27 6 2 4 3 5 17 33 94 165 101 67 65 65 87 71 84 132 143 104 55 42 30 15 13 5 4 1 5 8 19 70 113 198 74 64 73 75 95 99 116 136 148 88 40 32 34 8 3 1 2 2 6 16 32 66 169 149 72 68 60 90 93 78 178 143 165 69 52 45 26 8 7 5 5 3 11 15 43 110 172 140 73 70 64 93 75 99 189 141 150 74 53 23 24 12 4 6156
Report Generated by "Count Data" all rights reserved
Linscott, Law & Greenspan, Engineers
4542 Ruffner Street, Suite 100, San Diego, CA 92111
Average Daily Traffic
14512
8356
Location: BC 23-006 #02 East San Marcos Boulevard between Pico Avenue & Twin Oaks Valley Road Date: Thursday, January 26, 2023 Total Daily Volume: Description: Total Volume 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 139 96 74 130 302 682 1178 1936 2075 1545 1654 1753 1978 1735 2102 2602 2745 2887 1921 1272 975 703 472 241 36 32 21 29 39 94 260 375 532 434 390 475 483 415 442 622 653 728 609 353 263 159 161 66 48 27 22 31 73 146 254 455 553 369 399 431 523 427 497 664 664 743 532 292 243 221 94 57 20 14 16 33 108 223 323 489 521 366 406 408 486 434 547 674 720 722 364 260 223 199 125 62 35 23 15 37 82 219 341 617 469 376 459 439 486 459 616 642 708 694 416 367 246 124 92 56 Date: Thursday, January 26, 2023 Total Daily Volume: Description: Eastbound Volume 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 71 47 22 35 86 214 552 808 938 615 656 742 832 837 1064 1443 1399 1405 976 634 484 376 217 137 20 17 4 9 14 23 137 140 232 152 157 189 150 189 212 352 355 345 329 188 143 96 71 40 25 13 10 9 17 47 118 181 252 158 171 161 222 202 243 379 352 352 273 141 127 117 45 33 8 9 3 5 28 73 148 213 245 165 158 205 237 212 270 385 345 340 200 123 98 102 52 35 18 8 5 12 27 71 149 274 209 140 170 187 223 234 339 327 347 368 174 182 116 61 49 29 Date: Thursday, January 26, 2023 Total Daily Volume: Description: Westbound Volume 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 68 49 52 95 216 468 626 1128 1137 930 998 1011 1146 898 1038 1159 1346 1482 945 638 491 327 255 104 16 15 17 20 25 71 123 235 300 282 233 286 333 226 230 270 298 383 280 165 120 63 90 26 23 14 12 22 56 99 136 274 301 211 228 270 301 225 254 285 312 391 259 151 116 104 49 24 12 5 13 28 80 150 175 276 276 201 248 203 249 222 277 289 375 382 164 137 125 97 73 27 17 15 10 25 55 148 192 343 260 236 289 252 263 225 277 315 361 326 242 185 130 63 43 27 16607
Report Generated by "Count Data" all rights reserved
Linscott, Law & Greenspan, Engineers
4542 Ruffner Street, Suite 100, San Diego, CA 92111
Average Daily Traffic
31197
14590
Location: BC 23-006 #03 Pico Avenue between East Mission Road & East San Marcos Boulevard Date: Thursday, January 26, 2023 Total Daily Volume: Description: Total Volume 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 26 9 14 13 31 79 219 393 439 250 259 285 357 315 363 495 611 599 355 288 208 147 62 41 6 3 5 2 7 9 50 69 147 61 73 80 94 74 77 103 155 165 125 83 81 45 25 7 11 4 4 2 8 10 43 92 120 56 52 70 99 90 86 119 127 131 73 66 51 43 10 7 2 1 3 4 10 19 59 114 95 69 77 63 83 76 89 121 176 167 71 67 33 33 15 13 7 1 2 5 6 41 67 118 77 64 57 72 81 75 111 152 153 136 86 72 43 26 12 14 Date: Thursday, January 26, 2023 Total Daily Volume: Description: Northbound Volume 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 14 8 8 11 11 36 95 176 196 122 130 134 170 163 175 218 290 267 174 153 110 67 32 25 5 3 2 1 2 6 17 30 80 35 34 26 44 45 38 44 71 71 52 40 36 19 10 5 7 4 3 2 3 1 20 43 52 26 25 43 49 57 45 45 62 68 36 30 27 16 7 2 0 1 1 4 4 7 27 51 33 31 44 26 37 26 44 52 74 58 35 46 20 16 11 10 2 0 2 4 2 22 31 52 31 30 27 39 40 35 48 77 83 70 51 37 27 16 4 8 Date: Thursday, January 26, 2023 Total Daily Volume: Description: Southbound Volume 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 12 1 6 2 20 43 124 217 243 128 129 151 187 152 188 277 321 332 181 135 98 80 30 16 1 0 3 1 5 3 33 39 67 26 39 54 50 29 39 59 84 94 73 43 45 26 15 2 4 0 1 0 5 9 23 49 68 30 27 27 50 33 41 74 65 63 37 36 24 27 3 5 2 0 2 0 6 12 32 63 62 38 33 37 46 50 45 69 102 109 36 21 13 17 4 3 5 1 0 1 4 19 36 66 46 34 30 33 41 40 63 75 70 66 35 35 16 10 8 6 3073
Report Generated by "Count Data" all rights reserved
Linscott, Law & Greenspan, Engineers
4542 Ruffner Street, Suite 100, San Diego, CA 92111
Average Daily Traffic
5858
2785
LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-22-3709 Pico Avenue Apartments
N:\3709 - Pico Apts\Report\Attachments.3709.doc
ATTACHMENT B
SANDAG SCREENING MAP
LINSCOTT, LAW & GREENSPAN, engineers LLG Ref. 3-22-3709 Pico Avenue Apartments
N:\3709 - Pico Apts\Report\Attachments.3709.doc
ATTACHMENT C
EXISTING AND EXISTING + PROJECT INTERSECTION
ANALYSIS WORKSHEETS
HCM 6th TWSC Existing AM
2: Pico Ave & Project South Dwy/San Marcos Unified School District Dwy 01/26/2023 Pico Avenue Apartments Synchro 11 Report
3-22-3709 Page 2
Intersection
Int Delay, s/veh 1
Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations
Traffic Vol, veh/h 0 0 0 5 0 4 0 130 38 21 190 0
Future Vol, veh/h 0 0 0 5 0 4 0 130 38 21 190 0
Conflicting Peds, #/hr 10 0 10 10 0 10 10 0 10 10 0 10
Sign Control Stop Stop Stop Stop Stop Stop Free Free Free Free Free Free RT Channelized - - None - - None - - None - - None
Storage Length - - - - - - 30 - - 30 - -
Veh in Median Storage, # - 0 - - 0 - - 0 - - 0 -
Grade, % - 0 - - 0 - - 0 - - 0 -
Peak Hour Factor 92 92 92 38 38 38 81 81 81 85 85 85
Heavy Vehicles, % 2 22222222222
Mvmt Flow 0 0 0 13 0 11 0 160 47 25 224 0
Major/Minor Minor2 Minor1 Major1 Major2
Conflicting Flow All 374 501 244 478 478 124 234 0 0 217 0 0 Stage 1 284 284 - 194 194 -------
Stage 2 90 217 - 284 284 -------
Critical Hdwy 7.33 6.53 6.23 7.33 6.53 6.93 4.13 - - 4.13 - - Critical Hdwy Stg 1 6.13 5.53 - 6.53 5.53 -------
Critical Hdwy Stg 2 6.53 5.53 - 6.13 5.53 -------
Follow-up Hdwy 3.519 4.019 3.319 3.519 4.019 3.319 2.219 - - 2.219 - - Pot Cap-1 Maneuver 570 471 794 484 486 904 1332 - - 1351 - - Stage 1 722 676 - 790 740 -------
Stage 2 908 723 - 722 676 -------
Platoon blocked, % - - - -
Mov Cap-1 Maneuver 545 453 779 468 467 887 1319 - - 1338 - - Mov Cap-2 Maneuver 545 453 - 468 467 -------
Stage 1 715 656 - 782 733 -------
Stage 2 889 716 - 702 656 -------
Approach EB WB NB SB
HCM Control Delay, s 0 11.3 0 0.8
HCM LOS A B
Minor Lane/Major Mvmt NBL NBT NBR EBLn1WBLn1 SBL SBT SBR Capacity (veh/h) 1319 - - - 592 1338 - -
HCM Lane V/C Ratio ---- 0.04 0.018 - -
HCM Control Delay (s) 0 - - 0 11.3 7.7 - -
HCM Lane LOS A - - A B A - -
HCM 95th %tile Q(veh) 0 - - - 0.1 0.1 - -
HCM 6th TWSC Existing PM
2: Pico Ave & Project South Dwy/San Marcos Unified School District Dwy 01/26/2023 Pico Avenue Apartments Synchro 11 Report
3-22-3709 Page 2
Intersection
Int Delay, s/veh 0.8
Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations
Traffic Vol, veh/h 0 0 0 25 0 3 0 204 3 1 223 0
Future Vol, veh/h 0 0 0 25 0 3 0 204 3 1 223 0
Conflicting Peds, #/hr 10 0 10 10 0 10 10 0 10 10 0 10
Sign Control Stop Stop Stop Stop Stop Stop Free Free Free Free Free Free RT Channelized - - None - - None - - None - - None
Storage Length - - - - - - 30 - - 30 - -
Veh in Median Storage, # - 0 - - 0 - - 0 - - 0 -
Grade, % - 0 - - 0 - - 0 - - 0 -
Peak Hour Factor 92 92 92 78 78 78 88 88 88 68 68 68
Heavy Vehicles, % 2 22222222222
Mvmt Flow 0 0 0 32 0 4 0 232 3 1 328 0
Major/Minor Minor2 Minor1 Major1 Major2
Conflicting Flow All 466 585 348 584 584 138 338 0 0 245 0 0 Stage 1 340 340 - 244 244 -------
Stage 2 126 245 - 340 340 -------
Critical Hdwy 7.33 6.53 6.23 7.33 6.53 6.93 4.13 - - 4.13 - - Critical Hdwy Stg 1 6.13 5.53 - 6.53 5.53 -------
Critical Hdwy Stg 2 6.53 5.53 - 6.13 5.53 -------
Follow-up Hdwy 3.519 4.019 3.319 3.519 4.019 3.319 2.219 - - 2.219 - - Pot Cap-1 Maneuver 493 422 694 409 423 886 1220 - - 1320 - - Stage 1 674 639 - 739 703 -------
Stage 2 865 703 - 674 639 -------
Platoon blocked, % - - - -
Mov Cap-1 Maneuver 481 413 681 401 414 869 1208 - - 1307 - - Mov Cap-2 Maneuver 481 413 - 401 414 -------
Stage 1 667 632 - 732 696 -------
Stage 2 853 696 - 667 632 -------
Approach EB WB NB SB
HCM Control Delay, s 0 14.2 0 0
HCM LOS A B
Minor Lane/Major Mvmt NBL NBT NBR EBLn1WBLn1 SBL SBT SBR Capacity (veh/h) 1208 - - - 426 1307 - -
HCM Lane V/C Ratio ---- 0.084 0.001 - -
HCM Control Delay (s) 0 - - 0 14.2 7.8 - -
HCM Lane LOS A - - A B A - -
HCM 95th %tile Q(veh) 0 - - - 0.3 0 - -
HCM 6th TWSC Existing + P AM
1: Pico Ave & Project North Dwy 01/26/2023
Pico Avenue Apartments Synchro 11 Report
Intersection
Int Delay, s/veh 0.1
Movement EBL EBR NBL NBT SBT SBR
Lane Configurations
Traffic Vol, veh/h 1 3 1 135 211 0
Future Vol, veh/h 1 3 1 135 211 0
Conflicting Peds, #/hr 10 10 10 0 0 10
Sign Control Stop Stop Free Free Free Free
RT Channelized - None - None - None
Storage Length 0 - 30 - - -
Veh in Median Storage, # 0 - - 0 0 -
Grade, % 0 - - 0 0 -
Peak Hour Factor 92 92 81 81 85 85
Heavy Vehicles, % 2 22222
Mvmt Flow 1 3 1 167 248 0
Major/Minor Minor2 Major1 Major2
Conflicting Flow All 354 268 258 0 - 0
Stage 1 258 -----
Stage 2 96 -----
Critical Hdwy 6.63 6.23 4.13 - - -
Critical Hdwy Stg 1 5.43 -----
Critical Hdwy Stg 2 5.83 -----
Follow-up Hdwy 3.519 3.319 2.219 - - -
Pot Cap-1 Maneuver 631 770 1305 - - -
Stage 1 784 -----
Stage 2 917 -----
Platoon blocked, % - - -
Mov Cap-1 Maneuver 618 755 1293 - - -
Mov Cap-2 Maneuver 618 -----
Stage 1 775 -----
Stage 2 908 -----
Approach EB NB SB
HCM Control Delay, s 10.1 0.1 0
HCM LOS B
Minor Lane/Major Mvmt NBL NBT EBLn1 SBT SBR
Capacity (veh/h) 1293 - 715 - -
HCM Lane V/C Ratio 0.001 - 0.006 - -
HCM Control Delay (s) 7.8 - 10.1 - -
HCM Lane LOS A - B - -
HCM 95th %tile Q(veh) 0 - 0 - -
HCM 6th TWSC Existing + P AM
2: Pico Ave & Project South Dwy/San Marcos Unified School District Dwy 01/26/2023 Pico Avenue Apartments Synchro 11 Report
Intersection
Int Delay, s/veh 1.1
Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations
Traffic Vol, veh/h 1 0 3 5 0 4 1 131 38 21 193 0
Future Vol, veh/h 1 0 3 5 0 4 1 131 38 21 193 0
Conflicting Peds, #/hr 10 0 10 10 0 10 10 0 10 10 0 10
Sign Control Stop Stop Stop Stop Stop Stop Free Free Free Free Free Free RT Channelized - - None - - None - - None - - None
Storage Length - - - - - - 30 - - 30 - -
Veh in Median Storage, # - 0 - - 0 - - 0 - - 0 -
Grade, % - 0 - - 0 - - 0 - - 0 -
Peak Hour Factor 92 92 92 38 38 38 81 81 81 85 85 85
Heavy Vehicles, % 2 22222222222
Mvmt Flow 1 0 3 13 0 11 1 162 47 25 227 0
Major/Minor Minor2 Minor1 Major1 Major2
Conflicting Flow All 380 508 247 487 485 125 237 0 0 219 0 0 Stage 1 287 287 - 198 198 -------
Stage 2 93 221 - 289 287 -------
Critical Hdwy 7.33 6.53 6.23 7.33 6.53 6.93 4.13 - - 4.13 - - Critical Hdwy Stg 1 6.13 5.53 - 6.53 5.53 -------
Critical Hdwy Stg 2 6.53 5.53 - 6.13 5.53 -------
Follow-up Hdwy 3.519 4.019 3.319 3.519 4.019 3.319 2.219 - - 2.219 - - Pot Cap-1 Maneuver 565 467 791 477 481 903 1329 - - 1349 - - Stage 1 720 674 - 786 737 -------
Stage 2 904 720 - 718 674 -------
Platoon blocked, % - - - -
Mov Cap-1 Maneuver 540 449 776 459 462 886 1316 - - 1336 - - Mov Cap-2 Maneuver 540 449 - 459 462 -------
Stage 1 713 654 - 778 729 -------
Stage 2 884 712 - 695 654 -------
Approach EB WB NB SB
HCM Control Delay, s 10.2 11.4 0 0.8
HCM LOS B B
Minor Lane/Major Mvmt NBL NBT NBR EBLn1WBLn1 SBL SBT SBR Capacity (veh/h) 1316 - - 700 584 1336 - -
HCM Lane V/C Ratio 0.001 - - 0.006 0.041 0.018 - -
HCM Control Delay (s) 7.7 - - 10.2 11.4 7.7 - -
HCM Lane LOS A - - B B A - -
HCM 95th %tile Q(veh) 0 - - 0 0.1 0.1 - -
HCM 6th TWSC Existing + P PM
1: Pico Ave & Project North Dwy 01/26/2023
Pico Avenue Apartments Synchro 11 Report
Intersection
Int Delay, s/veh 0.1
Movement EBL EBR NBL NBT SBT SBR
Lane Configurations
Traffic Vol, veh/h 1 1 3 207 225 1
Future Vol, veh/h 1 1 3 207 225 1
Conflicting Peds, #/hr 10 10 10 0 0 10
Sign Control Stop Stop Free Free Free Free
RT Channelized - None - None - None
Storage Length 0 - 30 - - -
Veh in Median Storage, # 0 - - 0 0 -
Grade, % 0 - - 0 0 -
Peak Hour Factor 92 92 88 88 68 68
Heavy Vehicles, % 2 22222
Mvmt Flow 1 1 3 235 331 1
Major/Minor Minor2 Major1 Major2
Conflicting Flow All 476 352 342 0 - 0
Stage 1 342 -----
Stage 2 134 -----
Critical Hdwy 6.63 6.23 4.13 - - -
Critical Hdwy Stg 1 5.43 -----
Critical Hdwy Stg 2 5.83 -----
Follow-up Hdwy 3.519 3.319 2.219 - - -
Pot Cap-1 Maneuver 532 691 1215 - - -
Stage 1 718 -----
Stage 2 879 -----
Platoon blocked, % - - -
Mov Cap-1 Maneuver 520 678 1203 - - -
Mov Cap-2 Maneuver 520 -----
Stage 1 709 -----
Stage 2 870 -----
Approach EB NB SB
HCM Control Delay, s 11.1 0.1 0
HCM LOS B
Minor Lane/Major Mvmt NBL NBT EBLn1 SBT SBR
Capacity (veh/h) 1203 - 589 - -
HCM Lane V/C Ratio 0.003 - 0.004 - -
HCM Control Delay (s) 8 - 11.1 - -
HCM Lane LOS A - B - -
HCM 95th %tile Q(veh) 0 - 0 - -
HCM 6th TWSC Existing + P PM
2: Pico Ave & Project South Dwy/San Marcos Unified School District Dwy 01/26/2023 Pico Avenue Apartments Synchro 11 Report
Intersection
Int Delay, s/veh 0.9
Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations
Traffic Vol, veh/h 0 0 2 25 0 3 4 207 3 1 224 1
Future Vol, veh/h 0 0 2 25 0 3 4 207 3 1 224 1
Conflicting Peds, #/hr 10 0 10 10 0 10 10 0 10 10 0 10
Sign Control Stop Stop Stop Stop Stop Stop Free Free Free Free Free Free RT Channelized - - None - - None - - None - - None
Storage Length - - - - - - 30 - - 30 - -
Veh in Median Storage, # - 0 - - 0 - - 0 - - 0 -
Grade, % - 0 - - 0 - - 0 - - 0 -
Peak Hour Factor 92 92 92 78 78 78 88 88 88 68 68 68
Heavy Vehicles, % 2 22222222222
Mvmt Flow 0 0 2 32 0 4 5 235 3 1 329 1
Major/Minor Minor2 Minor1 Major1 Major2
Conflicting Flow All 480 600 350 600 599 139 340 0 0 248 0 0 Stage 1 342 342 - 257 257 -------
Stage 2 138 258 - 343 342 -------
Critical Hdwy 7.33 6.53 6.23 7.33 6.53 6.93 4.13 - - 4.13 - - Critical Hdwy Stg 1 6.13 5.53 - 6.53 5.53 -------
Critical Hdwy Stg 2 6.53 5.53 - 6.13 5.53 -------
Follow-up Hdwy 3.519 4.019 3.319 3.519 4.019 3.319 2.219 - - 2.219 - - Pot Cap-1 Maneuver 482 414 693 399 414 884 1217 - - 1316 - - Stage 1 672 637 - 726 694 -------
Stage 2 851 694 - 671 637 -------
Platoon blocked, % - - - -
Mov Cap-1 Maneuver 469 404 680 389 404 867 1205 - - 1303 - - Mov Cap-2 Maneuver 469 404 - 389 404 -------
Stage 1 663 630 - 716 684 -------
Stage 2 836 684 - 662 630 -------
Approach EB WB NB SB
HCM Control Delay, s 10.3 14.5 0.1 0
HCM LOS B B
Minor Lane/Major Mvmt NBL NBT NBR EBLn1WBLn1 SBL SBT SBR Capacity (veh/h) 1205 - - 680 413 1303 - -
HCM Lane V/C Ratio 0.004 - - 0.003 0.087 0.001 - -
HCM Control Delay (s) 8 - - 10.3 14.5 7.8 - -
HCM Lane LOS A - - B B A - -
HCM 95th %tile Q(veh) 0 - - 0 0.3 0 - -
Appendix C. Archaeological and Historic Resources Survey Report – Positive Findings
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ARCHAEOLOGICAL AND HISTORIC RESOURCES
SURVEY REPORT – POSITIVE FINDINGS
Pico Avenue Residential Project
Lead Agency:
City of San Marcos
1 Civic Center Drive
San Marcos, CA 92069
Preparers:
Donna Beddow, RPA, and Robert Bolger, RPA
Harris & Associates
600 B Street, Suite 2000
San Diego, CA 92101
(619) 236-1778
Project Proponent:
Pico Investments 7, LLC
2950 Paseo Sedano
San Juan Capistrano, CA 92675
July 2023
National Archaeological Data Base Information
Authors: Donna Beddow and Robert Bolger
Firm: Harris & Associates
600 B Street, Suite 2000
San Diego, CA 92101
(619) 236-1778
Client/Project Proponent: Pico Investments 7, LLC
2950 Paseo Sedano
San Juan Capistrano, CA 92675
Report Date: July 2023
Report Title: Archaeological and Historic Resources Survey Report – Positive Findings for the Pico Avenue Residential Project
Type of Study: Intensive Pedestrian/Phase I
New Sites: None
Updated Sites: P-37-014081
USGS Quad: San Marcos
Acreage: 0.68 acre
Key Words: Pedestrian Survey, Historic Structures, Luiseño Traditional Use Area
Acronyms
AB Assembly Bill
AD anno Domini
ADA Americans with Disabilities Act
APN Assessor’s Parcel Number
BP before present
CCR California Code of Regulations
CEQA California Environmental Quality Act
CHRIS California Historical Resources Inventory System
City City of San Marcos
CRHR California Register of Historical Resources
DPR California Department of Parks & Recreation
EIR Environmental Impact Report
MLD most likely descendant
NAHC Native American Heritage Commission
NETR Nationwide Environmental Title Research
NPS National Park Service
NRHP National Register of Historical Places
PRC California Public Resources Code
project Pico Avenue Residential Project
RPA Register of Professional Archaeologists
SB Senate Bill
SCIC South Coastal Information Center
USGS U.S. Geological Survey
WEAP Worker’s Environmental Awareness Program
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Archaeological and Historic Resources
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Pico Avenue Residential Project
TABLE OF CONTENTS
EXECUTIVE SUMMARY ...........................................................................................................1
1.0 INTRODUCTION.....................................................................................................2
1.1 Project Description ...............................................................................................2
1.2 Existing Conditions ..............................................................................................6
1.2.1 Environmental Setting ..............................................................................6
1.2.2 Records Search Results...........................................................................11
1.3 Applicable Regulations.......................................................................................14
1.3.1 State Level Regulations ..........................................................................14
1.3.2 City of San Marcos Regulations.............................................................18
1.3.3 Native American Traditional Cultural Properties...................................19
2.0 GUIDELINES FOR DETERMINING IMPACT SIGNIFICANCE..................20
3.0 ANALYSIS OF PROJECT EFFECTS .................................................................21
3.1 Methods ..............................................................................................................21
3.1.1 Survey Methods......................................................................................21
3.1.2 Laboratory and Cataloging Procedures...................................................21
3.1.3 Artifact Conveyance ...............................................................................21
3.1.4 Native American Participation/Consultation ..........................................22
3.2 Results.................................................................................................................22
4.0 INTERPRETATION OF RESOURCE IMPORTANCE AND IMPACT
IDENTIFICATION ................................................................................................23
4.1 Resource Importance ..........................................................................................23
4.1.1 Archaeological Resources.......................................................................23
4.1.2 Historic Resources..................................................................................23
4.1.3 Native American Heritage Resources/Traditional Cultural Properties...24
4.2 Impact Identification...........................................................................................24
5.0 MANAGEMENT CONSIDERATIONS – MITIGATION MEASURES
AND DESIGN CONSIDERATIONS....................................................................25
5.1 Worker’s Environmental Awareness Training ...................................................25
5.2 Pre-Excavation Agreement.................................................................................25
5.3 Construction Monitoring ....................................................................................26
5.4 Unanticipated Discoveries..................................................................................27
5.5 Human Remains..................................................................................................28
6.0 REFERENCES........................................................................................................30 Archaeological and Historic Resources
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7.0 LIST OF PREPARERS AND PERSONS AND ORGANIZATIONS
CONTACTED.........................................................................................................33
8.0 LIST OF MITIGATION MEASURES AND DESIGN
CONSIDERATIONS..............................................................................................34
FIGURES
Figure 1 – Regional Location ..........................................................................................................3 Figure 2 – Project Site......................................................................................................................4 Figure 3 – Site Plan..........................................................................................................................5 Figure 4 – Historic Aerial ..............................................................................................................15 TABLES
Table 1. Previous Studies within a 0.5-Mile Radius......................................................................12 Table 2. Previously Recorded Cultural Resources within a 0.5-Mile Radius ...............................12 Table 3. Previously Recorded Historic Addresses within a 0.5-Mile Radius................................14
APPENDICES
Appendix A. Photographs
Appendix C. DPR Forms
CONFIDENTIAL APPENDICES
(Bound Separately – Not for Public Review)
Confidential Appendix B. CHRIS Background Data
Confidential Appendix D. Sacred Lands File Check and Tribal Outreach Archaeological and Historic Resources
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Pico Avenue Residential Project
EXECUTIVE SUMMARY
The Pico Avenue Residential Project (project) is the development of a 16-unit multi-family residential condominium complex on 0.68 acre. Amenities would include a dog run and landscaped open space common areas. The site consists of two lots with three parcel numbers and is mostly undeveloped with two unoccupied structures on one of the parcels. Civic and commercial properties surround the parcels in all directions. The project is north of East San Marcos Boulevard, west of the North Coastal Consortium Schools and San Marcos Unified School District, east of Tiger Way and commercial development, and south of East Mission Road. The project is at 236– 244 Pico Avenue in the Richmar neighborhood of the City of San Marcos (City) in Section 11 of Township 12S, Range 03W, on the San Marcos U.S. Geological Survey quadrangle.
The cultural resources study consisted of a cultural resources survey of the project site, as well as documentation and evaluation of identified resources. Outreach to the list of Tribes provided by the Native American Heritage Commission (NAHC) was conducted, and none of the Tribes requested to participate in the survey within the 30-day comment period. The San Luis Rey Band of Mission Indians requested to participate in the survey if it had not been already conducted. Their response was received after the 30-day comment period and after the survey had been conducted.
One known historic resource, the San Marcos Forest Fire Station (P-37-014081), was relocated on site. It was documented, and California Department of Parks and Recreation (DPR) forms were updated. This site was determined to not be a significant resource under the California Environmental Quality Act (CEQA). The research potential of this resource has been fulfilled through documentation. No mitigation measures are required for this resource which would be subject to direct impacts.
The project is in an area with archaeological and cultural sensitivity. Therefore, a monitoring program should be implemented for any grading or other ground-disturbing activities as detailed in this report.
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1.0 INTRODUCTION
1.1 Project Description
The Pico Avenue Residential Project (project) is the development of a 16-unit multi-family residential condominium complex on 0.68 acre in northern San Diego County (Figure 1, Regional Location).
The project site is at 236–244 Pico Avenue in the City of San Marcos (City) on Assessor’s Parcel Numbers (APNs) 220-140-05-00, 220-140-06-00, and 220-140-16-00. The project site is bounded by the Boys and Girls Club and City Gym to the north, San Marcos Unified School District Offices to the east, the commercial enterprise Tasty Pizza and San Marcos Boulevard to the south, and a daycare center and existing parking lot to the west (Figure 2, Project Site). Regional access is provided via State Route 78, approximately 0.3 mile south of the project site. The project site is also approximately 0.25 mile west from the Civic Center Transit Station, which is served by the SPRINTER, the City’s light-rail system. The project site has an elevation of 560 feet above mean sea level, is relatively flat, and is within Section 11 of Township 12S, Range 03W, on the San Marcos U.S.
Geological Survey quadrangle. The property is suburban with close access to highways, employment, services, and amenities. The project site consists of two lots with three parcel numbers and is mostly undeveloped with two unoccupied structures on one of the parcels.
The project would consist of 16 two-bedroom units in four buildings on 0.68 acre, with each building composed of three floors with two-car garages on the first floor (Figure 3, Site Plan). The height of the four buildings would be 37.25 feet. The four buildings footprint would comprise 0.2 acre of the project site, the parking and drives would comprise 0.22 acre, and the remaining 0.26 acre would be landscaping and open space. The total square footage of the four buildings would be 18,656 square feet, including the area of all three floors in each two-bedroom unit. The project would provide 38 parking spaces, including 32 covered garage parking spaces and six guest parking spaces. The 32 covered garage parking spaces would be on the first floor of the units (two per unit), and the six guest parking spaces would be in an uncovered lot and include one Americans with Disabilities Act (ADA) parking space. The project would provide 8,527 square feet of common open space and 2,824 square feet of private open space in six units with private courtyards and balconies. A dog run would be along the northern edge of the project site, that would be accessible to the public and consist of turf to reduce water use on site. The common open space along the northern edge of the project site would also include an area with children’s play equipment. A 4-foot-tall decorative block wall (consisting of a 2- foot retaining and 2-foot freestanding wall) with a 4-foot-tall tubular steel fence would be constructed along the eastern and portions of the northern perimeter of the property, and a 6-foot-tall block wall would be constructed along the western perimeter and portions of the southern perimeter of the property. Sidewalk improvements would be made along the southern perimeter of the property.
The project would make improvements to the sidewalk along Pico Avenue frontage to improve pedestrian access to nearby sites. Further improvements would include native or drought-tolerant landscaping consisting of various street trees along the project frontage, as well as parking lot trees, accent flowers, and shrubs throughout the common areas.
The study consists of a field survey of the project site and evaluation of resources, as well as documentation and recordation. Harris senior archaeologist Donna Beddow served as the principal investigator. Robert Bolger (archaeologist) served as the field crew leader, and Jasmine Alvarez-Ceja (junior archaeologist) assisted with the survey and evaluation.
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1.2 Existing Conditions
1.2.1 Environmental Setting
Natural Environment
The project is in the northern valley ecological subregion and within the Coastal Climate Zone.
The area is characterized as “Mediterranean hot summer” (Griner and Pryde 1976), with average summer high temperatures ranging from high 70s to low 80s (June through September) and average winter low temperatures in the high 40s (December, January, February) (Weather U.S. 2023). The northern half of the project site is undeveloped and contains disturbed habitat; the southern portion contains two unoccupied structures and a circular driveway. The surrounding area is primarily civic and commercial development. One parcel of undeveloped land is east and across Pico Avenue from the project site.
Cultural Environment
Prehistoric
Cultural resources are found throughout San Diego County and are reminders of the county’s 10,000-year-old historical record. Cultural resources are the tangible or intangible remains or traces left by prehistoric or historical people who inhabited the San Diego region. They encompass both the built (post-1769) and the archaeological environments. Cultural resources are typically in protected areas near water sources and multiple ecoregions and can include Traditional Cultural Places, such as gathering areas, landmarks, and ethnographic locations.
The following provides a brief cultural background for San Diego County and the City of San Marcos.
Paleoindian Period (pre-5500 BC)
Several terms are used for the early occupation of the San Diego region and include Paleoindian period, Early Archaic period, Initial period, and Scraper Maker period (Moratto 1984). This period dates from 9000 to 5500 BC (Chartkoff and Chartkoff 1984; Moratto 1984; Rogers 1966; Taylor and Meighan 1978; Warren and True 1961). Early humans have been characterized as an early nomadic, hunting culture whose settlements were located on mesas and ridge tops and in deserts (Erlandson and Colton 1991; Rogers 1966; Wallace 1978; Warren et al. 1961). During this period, inhabitants relied on large game for subsistence (Rogers 1966; Warren et al. 1961) and produced “finely worked blades, spear points, choppers, and scrapers out of fine-grained volcanics” (Carrico 1977). In addition, leaf-shaped knives, foliate to ovoid bifaces, foliate to shortbladed shoulder points, crescents, engraving tools, core hammers, pebble hammers, and cores were part of the tool assemblage (Moratto 1984; Wahoff and Dolan 2000). Pottery and milling stones were missing from the assemblage, confirming the assumption that hunting was an economic focus for the culture (Moriarty 1967; Warren and True 1961). Because the tool assemblage was similar to desert cultures of the Mojave Desert, it is believed that this culture migrated west from the desert into California (Gallegos 1995; Rogers 1939). However, no single hypothesis is universally accepted. Other hypotheses identify the movement of people into California from the south and north down the coast (Taylor and Meighan 1978; Chartkoff and Chartkoff 1984).
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Archaic Period (8000 BC–AD 500)
According to Hale et al. (2018), “the more than 1500-year overlap between the presumed age of Paleoindian occupations and the Archaic period highlights the difficulty in defining a cultural chronology in the San Diego region.” The Archaic period is also known as La Jollan, Millingstone Horizon and Encinitas Tradition. This period is characterized by the presence of dart points, milling, equipment, scattered hearths, shell middens, and flexed burials (Carrico 1977).
Subsistence strategies placed an emphasis on gathering, possibly as a result of environmental change (Wahoff and Dolan 2000; Wallace 1978). The assemblage was composed of milling implements and cobble/core-based tools. The flaked tools do not appear to be as refined as those of the Paleoindian period. Mortuary goods included shell beads and ornaments, projectile points, and milling implements. Wallace (1978) interpreted archaeological sites of this period as an indication of an increase in population and permanence. Site types included coastal shell habitation bases, quarries, resource exploitation, and milling (Gallegos 1995). The sites are typified by an abundance of shellfish remains and are situated near sloughs and lagoons and on the open coast (Carrico 1977; Masters and Gallegos 1997; Moratto 1984; Wallace 1978). An inland manifestation identified as the Pauma complex is known to have existed (True 1958). Unlike the coastal people, this complex occupied “transverse valleys and sheltered canyons of inland San Diego County, ha[d] an emphasis on hunting and gathering, had a greater diversity of tool types, and lacked shellfish remains” (Masters and Gallegos 1997:12).
Similar to the Paleoindian period, controversy surrounds the origins of the Archaic culture. Several hypotheses have been postulated. Kaldenberg (1976) and Moriarty (1967) proposed that the transition from the Paleoindian to the Archaic culture was an in-situ adaptation. In contrast, Warren and True (1961) viewed this transition as a migration from the desert to the coast due to the adverse environmental condition of the Altithermal. Taylor and Meighan (1978:36) did not take a single position regarding the transition to the Archaic culture but, rather, incorporated all of the hypotheses as identified below:
The artifact inventory and cultural activities argue strongly that this stage began in the desert inland and spread toward the Pacific Coast, reaching it about 8500 years ago. There is no evidence to show whether the Milling Stone Stage involved movement of the people or a conquest of earlier residents; perhaps the early hunters simply adopted this way of life as game animals became scarce.
The population of this period focused on lagoonal resources and moved up and down the river valleys exploiting a variety of inland and coastal resources (Masters and Gallegos 1997).
Late Prehistoric (AD 500-1769)
The Late Prehistoric period is an antecedent to Spanish contact (AD 1000–1769). It was a “time of cultural transformations brought about by trait diffusion, immigration, and in-situ adaptation to environmental changes” (Moratto 1984:153). Subsistence strategies involved a focus on terrestrial collection and hunting (Christenson 1992); however, shellfish and other maritime resources were also used. Settlement included large villages near permanent water sources, temporary campsites, quarries, and resource exploitation sites. Small triangular points, pottery, and Obsidian Butte obsidian are characteristic of this period (Christenson 1992; Masters and Gallegos 1997; True 1966, 1970). Cremations replaced flexed inhumations, and mortuary goods became more Archaeological and Historic Resources
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Pico Avenue Residential Project
elaborate (Wallace 1955). Cremations are believed to have been introduced into the area during the Late Prehistoric period and are the result of Shoshonean intrusion (1500 BP) from the deserts (True 1966) into northern San Diego County. However, in the southern part of the County, this practice has been attributed to a “Colorado River origin that may have had an influence as far reaching as the Hohokam [current day Pima people and Tohono O’odham Nation] in southwestern Arizona” (True 1970:58). Kaldenberg (1976:67) had a different opinion on the origin and timing of the entrance of cremation practices into the region. He noted that the practice of cremation was introduced at the terminus of the Archaic culture (3000 BP) with the “migration of Yuman people into the San Diego coastal region.” By 2000 BP, inhumations were replaced by cremations (Kaldenberg 1976).
Two complexes (San Luis Rey and Cuyamaca) are identified with the Late Prehistoric period. True (1966) believed that the San Luis Rey complex was a precursor to the ethnographic Luiseño.
Similarly, he suggested that the Cuyamaca complex was the predecessor to the ethnographic Kumeyaay. Through the examination of both geographic regions, True identified specific characteristics unique to each; however, he noted that, although geographically similar, these two cultures were distinctly different.
Ethnohistoric Period (post-AD 1769)
The Ethnohistoric period begins with the first permanent European settlements. Early Ethnohistoric accounts and mission documents have been used to reconstruct this period (Hale et al. 2018). Florence Shipek (1993) delineated the boundaries between the Luiseño and the Kumeyaay as follows:
In 1769, the Kumeyaay national territory started at the coast about 100 miles south of the Mexican border (below Santo Tomas), thence north to the coast at the drainage divide south of the San Luis Rey River including its tributaries. Using the U.S.
Geological Survey topographic maps, the boundary with the Luiseño then follows that divide inland. The boundary continues on the divide separating Valley Center from Escondido and then up along Bear Ridge to the 2240 contour line and then north across the divide between Valley Center and Woods Valley up to the 1880-foot peak, then curving around east along the divide above Woods Valley.
Various archaeologists and ethnographers use slightly different boundaries. In addition, traditional stories and songs of the Native people also describe the extent of traditional use areas. The project site is in the traditional territory of the Luiseño people.
According to Hale et al. (2018):
Ethnohistorical and ethnographic evidence indicates that the Shoshonean-speaking group that occupied the northern portion of San Diego County were the Luiseño. Along the coast, the Luiseño made use of the marine resources available by fishing and collecting molluscs for food. Seasonally available terrestrial resources, including acorns and game, were also sources of nourishment for Luiseño groups. The elaborate kinship and clan systems between the Luiseño and other groups facilitated a widereaching trade network that included trade of Obsidian Butte obsidian, resources from the eastern deserts, and steatite from the Channel Islands.
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When contacted by the Spanish in the sixteenth century, the Luiseño occupied a territory bounded on the west by the Pacific Ocean, on the east by the Peninsular Range mountains, including Palomar Mountain to the south and Santiago Peak to the north, on the south by Agua Hedionda Lagoon, and on the north by Aliso Creek in presentday San Juan Capistrano. The Luiseño shared boundaries with the Gabrieleño to the west and northwest, the Cahuilla to the east, the Cupeño to the southeast, and the Ipai to the south. The Luiseño were a Takic-speaking people more closely related linguistically and ethnographically to the Cahuilla, Gabrielino, and Cupeño to the north and east rather than to the Kumeyaay, a Yuman-speaking group who occupied territory to the south. The Luiseño had an abundance of social statuses, a system of ruling families that provided ethnic cohesion within the territory, a distinct world view, and an elaborate religion that included ritualized sand paintings of the sacred being “Chingichngish” (Bean and Shipek 1978; Kroeber 1925).
The Luiseño were organized into patrilineal clans or bands centered on a chief, comprised of 25–30 people (Kroeber 1925), each of which had their own territorial land or range where food and other resources were collected at different locations throughout the year (Sparkman 1908). The title of chief was heritable along family lines. Inter-band conflict was most common over trespassing. Sparkman observed that “when questioned as to when or how the land was divided and sub-divided, the Indians say they cannot tell, that their fathers told them that it had always been thus.” (1908).
Place names were assigned to each territory, often reflecting common animals, plants, physical landmarks, or cosmological elements that were understood as being related to that location.
The general area was used by the Luise o as evidenced by the presence of cultural sites that have been recorded. These sites include bedrock milling, habitation, lithic and ceramic scatters, and shell scatters.
Historic Period (post-AD 1542)
The Historic period can be divided into three phases (Spanish, Mexican, and American).
Each phase is identified with a change in political power. Common goals in each phase included land gain, assimilation of the native population, and the attainment of wealth. However, these periods were dissimilar in the rationale behind these goals. Rationale included defense (Spain), independence and secularization (Mexico), and expansion and economics (United States).
Assimilation of Native Californians was a desire of each government that came to power; however, the greatest misfortune of this period was the large decline in Native American populations (Phillips 1981).
Spanish Period (AD 1769–1821)
Although the first Spanish contact occurred in 1542, it was not until 1769 that the first permanent settlement was established. The Spanish period was a time of European expansionism and is typically identified with the mission system. In addition, presidios (military defense) and pueblos (city government) played an important role in the structuring of the community (Campbell 1977).
The mission system was the institution designated for the assimilation and exploitation of native people (Campbell 1977; Cline 1979; Jackson and Castillo 1995; Phillips 1981). Jackson and Castillo (1995:6) identified this exploitation as an extension of the “sixteenth-century policy of Archaeological and Historic Resources
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congregacion/reduction.” In contrast, Costo (1987) noted that the transference of the Spanish Inquisition (originally established in 1478) to the New World was the mechanism for this exploitation because the Inquisition contained economic and religious incentives. The Spanish stronghold in California declined with Spain’s loss of the Napoleonic Wars (1803–1815), which eliminated funding to the mission.
Mexican Period (AD 1821–1859)
Mexican independence from Spain occurred in 1821, and in 1833, Mexico secularized the missions. After secularization, large tracts of land were granted to private citizens. “The secularization of the missions during the Mexican period is usually regarded as a watershed in California History because it resulted in the replacement of one Hispanic institution by another – the rancho for the mission” (Phillips 1981:33). Like the mission, the rancho became the institution of native exploitation. This period experienced an increase in cattle ranching and the hide and tallow trade (Gallegos 1995; Wahoff and Dolan 2000). The passage of the Treaty of Guadalupe Hidalgo that ended the Mexican–American War in 1848 was the final event that culminated the Mexican period in California.
American Period (Post-AD 1850)
The concept of a two-ocean economy and the California Gold Rush were the impetus that brought about the annexation of California (1850) to the United States. A large number of immigrants entered California with the discovery of gold and the availability of free land with the passage of the Homestead Act (1863). This population increase caused the displacement of Native Californians and brought about a deterioration in their rituals and traditions (Carrico 1986; Gallegos 1995). During this period, the ranchos experienced a decline primarily in response to their inability to validate land ownership as a result of the California Land Claims Act of 1851. “With the discovery of gold, the building of the transcontinental railroad, and the development of crops and cities, people in massive numbers from all parts of the world began to inhabit the region” (Phillips 1981: editors’ introduction).
City of San Marcos
The following history of San Marcos is from the San Marcos General Plan (City of San Marcos 2012).
According to legend, San Luis Rey Mission livestock were robbed by a small band of Native Americans in the late 1700s. Fleeing the Spanish troops, the Native Americans escaped to the hills.
While in pursuit of their livestock, the Spaniards came upon a fertile valley in 1797, which was named Los Vallecitos de San Marcos (Little Valleys of Saint Mark) to honor the day of discovery:
April 25, or “St. Mark’s Day.” On April 22, 1840, Governor Juan Bautista Alvarado granted Los Vallecitos de San Marcos to his relative, Jose Mario Alvarado. In 1846, Jose Alvarado was killed, and the land was left to his wife. She then sold the land to Lorenzo Soto. In the late 1850s, Soto sold part of his land to Cave Couts. Soon his family was raising livestock. Although Cave Couts owned the land, Major Gustavus French Merriam from Topeka, Kansas, made the first permanent settlement. Merriam homesteaded 160 acres in the North Twin Oaks Valley area and began wine and honey production.
After Major Merriam’s settlement, German and Dutch immigrants began moving into the area in the early 1880s. In 1883, a few miles south of the settlement, John H. Barham founded the first Archaeological and Historic Resources
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town in the area, aptly naming it Barham. By 1884, the town of Barham had a post office, blacksmith, feed store, and weekly newspaper. In 1887, the San Marcos Land Company bought almost all of the San Marcos land formerly owned by the Couts family and promptly divided the land into tracts. Soon the beautiful hills began attracting home-seekers.
The original town of San Marcos was at the intersection of what is now Grand Avenue and Rancho Santa Fe Road. In 1887, the Santa Fe Railroad announced that it was going to lay tracks through the valley, but, to the disappointment of the citizens, the tracks were laid 1 mile away from the center of the town. By 1896, San Marcos was a community with its own stores, post office, blacksmith, and railroad depot. In 1903, the town appeared to be going downhill, so the people picked up and moved along the railroad tracks to what now are Mission Road and Pico Avenue.
In 1905, the town had every convenience, including rural mail delivery and telephone service.
The first school in the area, which had started in Barham in 1880, was moved in 1889 to San Marcos. Later that same year, the Richland School was built, being the second school in San Marcos. The main business in San Marcos in the 1800s and early 1900s was farming. Then in the mid-1900s, dairies and poultry production became a big part of the economy in the town.
San Marcos initially started to grow rapidly in 1956 when the first water from the Colorado River arrived. After the arrival of water, several small businesses started, and the population increased to 2,500. In 1950, the first dirt was turned for construction of what is now State Route 78.
San Marcos’ first high school was completed in June 1961. San Marcos incorporated as a city on January 28, 1963. Through the 1960s, the City grew by a few thousand new residents, but by the 1970s, San Marcos was flourishing as the third fastest growing city in the state, with a population of 17,479 by 1980. Between the years of 1980 and 1990, San Marcos more than doubled its population to 38,974. By 2010, the population of the City had grown to 83,781, a 52 percent growth from the 2000 population.
Along with more people came the need for more schools. The City now has 11 elementary schools, an English-Learner Academy, 3 middle schools, and 3 high schools. San Marcos also has one charter school and one adult school. Higher education has become a benchmark for the City, as the home to Palomar Community College, California State University San Marcos, and several private higher education institutes specializing in the high technology and medical fields.
1.2.2 Records Search Results
Harris staff conducted a records search of the surrounding area using the California Historical Resources Inventory System (CHRIS) (Confidential Appendix B, CHRIS Background Data).
Six studies have been conducted within a half-mile radius (Table 1, Previous Studies within a 0.5-Mile Radius), and 17 sites were identified (Table 2, Previously Recorded Cultural Resources within a 0.5-Mile Radius). One study (Thornton 1994) has been conducted for the project site or portion thereof. The Thornton study was positive for the presence of one historic resource (San Marcos Forest Fire Station Gas & Oil House).
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Table 1. Previous Studies within a 0.5-Mile Radius
Report ID Title Author Year
SD-01031
Archaeological Report for Business/Industrial,
Richmar, Lake San Marcos and Barham/Discovery
Community Plan, San Marcos, California
Dennis Gallegos 1983
SD-02043
Draft Environmental Impact Report San Marco Flood
Control Channel San Marcos Creek/Las Posas
Reach SCH #88061505
Michael Brandman Associates, Inc. 1989
SD-07729 Management Plan for CDF’s Historic Buildings and Archaeological Sites Daniel G. Foster and Mark Thornton 2000 SD-07751 A Survey and Historic Significance Evaluation of the CDF Building Inventory Mark Thornton 1994
SD-14140
Archaeological Records Search and Literature
Review, Vallecitos Water District Master Plan
Update, San Diego County, California
Mary Robbins-Wade 2003
N/A Westlake Village Archaeological Monitoring Mary Robbins-Wade 2012 Notes: ID = identification; CDF = California Department of Forestry and Fire Protection; N/A = not available Table 2. Previously Recorded Cultural Resources within a 0.5-Mile Radius Primary
Number Trinomial
Chronological
Placement Site Type Size Recorder, Date
P-37-005632 CA-SDI-5632 Prehistoric BRM with Lithic &
Shell Scatter
50x70 yards Randy Franklin, 1977;
Unknown, 1996;
S. Briggs,
T. Stonebumer,
M. Robbins-Wade, 2012
P-37-008720 CA-SDI-8720 Prehistoric BRM Not Provided C. Carrillo, H. Price, 1981;
Ron Bissell, 1991;
Shelby Castells, 2011;
Shelby Castells, 2014
P-37-012095 CA-SDI-12095 Prehistoric Temporary Camp 100x40 meters Andrew Pigniolo, Bert Rader, 1991;
D. Gallegos, M.
Guerrero, 2007
P-37-012098 CA-SDI-12098 Prehistoric Lithic Scatter 30x30 meters Ron Bissell, 1991; Andrew Pigniolo,
Steven H. Briggs, 1991
P-37-012210 CA-SDI-12210 Prehistoric Isolate – Lithics 10x4 meters Kathie Joyner, 1990 P-37-014081 N/A Historic Building – San
Marcos Forest Fire
Station
1,344 square
feet
Mark V. Thornton, 1994
P-37-015578 N/A Prehistoric Isolate – Mano N/A Delman James, Rich Bark, Ted Cooley, 1996
P-37-015579 N/A Prehistoric Isolate – Mano N/A Delman James, Rich Bark, Ted Cooley, 1996
P-37-030656 CA-SDI-19475 Prehistoric Lithic Scatter 60x60 meters M. Sivba, T. Biegger, K. Knabb, 2006
P-37-030657 N/A Prehistoric Isolate – Lithic N/A M. Sivba, T. Biegger, K. Knabb, 2008
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Table 2. Previously Recorded Cultural Resources within a 0.5-Mile Radius Primary
Number Trinomial
Chronological
Placement Site Type Size Recorder, Date
P-37-030745 CA-SDI-19524 Prehistoric Lithic & Ceramic
Scatter
25x10 meters A. Giletti, J. Meriwether,
N.Cox, M. Sivba,
S. Mojado, 2009
P-37-033557 N/A Historic Highway 395 190x20 feet Larry Tift, 2013; Kent Manchen,
Matt DeCarlo,2015;
Haley Chateene, 2017;
A. Foglia, K. Keckeisen,
2017;
Sarah Stringer-Bowsher,
2018
P-37-033844 CA-SDI-21254 Multi-Component Lithic Scatter Human Remains
House Ruins
25x20 meters T. Quach, S. StringerBowsher, 2014;
Shelby Castells,
Lucas Piek, Matthew M.
DeCarlo, 2015
P-37-036140 N/A Historic Commercial
Building – 304 West
Mission Road
Not Provided Jennifer Gorman &
Shelby Castells, 2014
P-37-036141 N/A Historic Commercial
Building – 312-318
West Mission Road
Not Provided Jennifer Gorman &
Shelby Castells, 2014
P-37-039597 CA-SDI-23151 Prehistoric Lithic Scatter 3x3 meters Brian F. Smith, 2021 P-37-039617 CA-SDI-23161 Multi-Component BRM
Historic Features
P-37-039617 CA-SDI-23161
Notes: BRM = bedrock milling; N/A = not applicable
Three historic addresses, which are also identified as previous resources, were identified (Table 3, Previously Recorded Historic Addresses within a 0.5-Mile Radius). Of the previously recorded sites, eight are prehistoric (P-37-005632/CA-SDI-5632, P-37-008720/CA-SDI-8720, P-37-012095/CA-SDI-12095, P-37-012098/CA-SDI-12098, P-37-030656/CA-SDI-19475, P-37-030745/CA-SDI-19524, P-37-039597/CA-SDI-23151, and P-37-039617/CA-SDI-23161), three are historic (P-37-014081, P-37-033557, and P-37-036140), two are multi-component (P-37-014081 and P-37-036141), and four are prehistoric isolates (P-37-12210, P-37-015578, P-37-015579, and P-37-030657). The nearest archaeological resources (lithic scatter) are approximately 0.25 mile west (P-37-012098) and north (P-37-012210) of the project site.
One historic resource, the San Marcos Forest Fire Station Gas & Oil House is present on site.
The San Marcos Forest Fire Station Gas & Oil House is located at 236 Pico Avenue. This resource was originally documented in 1994 by Mark Thornton. It was identified as a 1939 combination barracks and two-bay truck garage. The structure is described as a single-story wood-frame building that was constructed in an “L” floor plan in a Craftsman Bungalow architectural style. The structure has been remodeled and enlarged since its original construction.
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Table 3. Previously Recorded Historic Addresses within a 0.5-Mile Radius Primary Number Address Historic Name Common Name
P-37-014081 236 Pico Avenue San Marcos Fire Control
Station Combination
Barracks
San Marcos Forest Fire
Station Gas & Oil House
Not Provided 341 Richmar Avenue Unknown Unknown
Not Provided 358 Fitzpatrick Road Unknown Unknown
In addition to the South Coastal Information Center (SCIC) records search, Harris conducted an online review of historic aerial photographs of the project site and general vicinity, to identify the historic development of the project site (Figure 4, Historic Aerial). Historic aerials were available for 1938, 1947, 1953, 1964, 1967, 1978, 1980-1991, 1993–2000, 2002, 2003, 2005, 2009, 2010, 2012, 2014, 2016, 2018, and 2020 (NETR Online 2023).
The historic aerial from 1938 indicates no development for the project site; however, by 1947 structures and a circular driveway are present. In 1953 adjacent properties were in agricultural use, and by 1964 development in the surrounding area is present. By the mid-1980s, major roadways and additional development are extant. The early 1990s illustrate commercial development around the project site.
The area remains essentially the same until 2009, when civic uses are introduced east of the project.
Historic topographic maps of the project site were also reviewed (earliest map available is 1872). The historical topographic maps from 1942, 1948, and 2019 identify structures on the project site.
1.3 Applicable Regulations
Cultural resource regulations that apply to the project site are CEQA, California Health and Safety Code, and provisions of the California Register of Historical Resources. Historic and archaeological districts, sites, buildings, structures, and objects are assigned significance based on their exceptional value or quality in illustrating or interpreting the heritage of San Marcos in history, architecture, archaeology, engineering, and culture. A number of criteria are used in demonstrating resource importance.
1.3.1 State Level Regulations
California Environmental Quality Act
According to CEQA, a resource shall be considered by the lead agency to be “historically significant” if the resource meets the criteria for listing on the California Register of Historical Resources (California Public Resources Code, Section 5024.1; California Code of Regulations, Title 14, Section 4852) including the following:
1. Is associated with events that have made a significant contribution to the broad patterns of California’s history and cultural heritage
2. Is associated with the lives of persons important in our past
3. Embodies the distinctive characteristics of a type, period, region, or method of construction, or represents the work of an important creative individual, or possesses high artistic values
4. Has yielded, or may be likely to yield, information important in prehistory or history Figure 4. Historic Aerial
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The fact that a resource is not listed in or determined to be eligible for listing in the California Register of Historical Resources (CRHR), not included in a local register of historical resources (pursuant to Section 5020.1(k) of the California Public Resources Code), or not identified in an historical resources survey (meeting the criteria in Section 5024.1[g] of the CEQA Guidelines) does not preclude a lead agency from determining that the resource may be an historical resource as defined in California Public Resources Code, Section 5020.1(j) or 5024.1.
California Register of Historical Resources (California Public Resources Code, Section 5020 et seq.) In California, the term “historical resource” includes but is not limited to “any object, building, structure, site, area, place, record, or manuscript which is historically or archaeologically significant, or is significant in the architectural, engineering, scientific, economic, agricultural, educational, social, political, military, or cultural annals of California” (California Public Resources Code, Section 5020.1[j]). In 1992, the California legislature established the CRHR “to be used by state and local agencies, private groups, and citizens to identify the state’s historical resources and to indicate what properties are to be protected, to the extent prudent and feasible, from substantial adverse change” (California Public Resources Code, Section 5024.1[a]).
A resource is eligible for listing in the CRHR if the State Historical Resources Commission determines that it is a significant resource and that it meets any of the following National Register of Historic Places (NRHP) criteria (California Public Resources Code, Section 5024.1[c]):
1. Associated with events that have made a significant contribution to the broad patterns of California’s history and cultural heritage
2. Associated with the lives of persons important in our past
3. Embodies the distinctive characteristics of a type, period, region, or method of construction, or represents the work of an important creative individual, or possesses high artistic values
4. Has yielded, or may be likely to yield, information important in prehistory or history Resources less than 50 years old are not considered for listing in the CRHR but may be considered if it can be demonstrated that sufficient time has passed to understand the historical importance of the resources (refer to California Code of Regulations, Title 14, Section 4852[d][2]).
The CRHR protects cultural resources by requiring evaluations of the significance of prehistoric and historical resources. The criteria for the CRHR are nearly identical to those for the NRHP, and properties listed or formally designated as eligible for listing on the NRHP are automatically listed on the CRHR, as are the state landmarks and points of interest. The CRHR also includes properties designated under local ordinances or identified through local historical resource surveys. The State Historic Preservation Officer maintains the CRHR.
California Points of Historic Interest
California Points of Historical Interest are buildings, structures, sites, or features of local (city and county) significance that have anthropological, cultural, military, political, architectural, economic, scientific/technical, religious, experimental, or other value. Points of Historical Interest designated after December 1997 are recommended by the State Historical Resources Commission to also be listed in the CRHR. The criteria for designation of Points of Historical Interest are the same as those that govern the California Historical Landmarks program.
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California Health and Safety Code, Section 7050.5
California law protects Native American burials, skeletal remains, and associated grave goods, regardless of their antiquity, and provides for the sensitive treatment and disposition of those remains. California Health and Safety Code, Section 7050.5, requires that if human remains are discovered in any place other than a dedicated cemetery, no further disturbance or excavation of the site or nearby area reasonably suspected to contain human remains shall occur until the county coroner has examined the remains (Section 7050.5b). If the coroner determines or has reason to believe the remains are those of a Native American, the coroner must contact the NAHC within 24 hours (Section 7050.5c). The NAHC will notify the most likely descendant (MLD). With the permission of the landowner, the MLD may inspect the site of discovery. The inspection must be completed within 24 hours of notification of the MLD by the NAHC. The MLD may recommend means of treating or disposing of, with appropriate dignity, the human remains and items associated with Native Americans.
California Health and Safety Code, Section 8010–8011
This code is intended to provide consistent state policy to ensure that all California Native American human remains and cultural material are treated with dignity and respect. The code extends policy coverage to non-federally recognized Tribes and federally recognized groups.
Native American Historic Cultural Sites (California Public Resources Code, Section 5097 et. seq.) State law addresses the disposition of Native American burials in archaeological sites and protects such remains from disturbance, vandalism, or inadvertent destruction; establishes procedures to be implemented if Native American skeletal remains are discovered during construction of a project; and establishes the NAHC to resolve disputes regarding the disposition of such remains.
In addition, the Native American Historic Resource Protection Act makes it a misdemeanor punishable by up to 1 year in jail to deface or destroy Native American historic or cultural site that is listed or may be eligible for listing in the CRHR.
Assembly Bill 2461
Assembly Bill (AB) 2461 provides procedures for private landowners to follow upon discovering Native American human remains. Landowners are encouraged to consider culturally appropriate measures if they discover Native American human remains as set forth in California Public Resources Code, Section 5097.98
Senate Bill 18
Senate Bill (SB) 18, approved in 2004, amends the California Civil Code and the California Government Code, requiring cities and counties to contact and consult with California Native American Tribes prior to adopting or amending any general plan or specific plan, or designating land as open space in order to preserve or mitigate impacts to specified Native American places, features, and objects that are located within the city’s or county’s jurisdiction. SB 18 also requires cities and counties to hold in strict confidence any information about the specific identity, location, character or use of these resources. In 2005, the Governor’s Office of Planning and Research published Tribal Consultation Guidelines to guide cities and counties on the process of engaging in consultation in accordance with SB 18. The NAHC maintains a list of California Native American Tribes with whom cities and counties must consult pursuant to SB 18.
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Assembly Bill 52
AB 52 was approved in 2014 and adds new requirements regarding consultation with California Native American Tribes and consideration of tribal cultural resources. The law went into effect on July 1, 2015, and after that date, if requested by a California Native American Tribe, lead agencies must consult prior to the release of a negative declaration, mitigated negative declaration, or draft Environmental Impact Report (EIR).
1.3.2 City of San Marcos Regulations
General Plan
The Conservation and Open Space Element of the San Marcos General Plan (City of San Marcos 2012) includes the following cultural resources goals:
Goal COS-2 The City is committed to conserving, protecting, and maintaining open space, agricultural, and limited resources for future generations. By working with property owners, local organizations, and state and federal agencies, the City can limit the conversion of resource lands to urban uses.
Policy COS-2.5 Continue to review future development proposals to ensure that cultural resources (including prehistoric, historic, paleontological, and Senate Bill 18 Tribal resources) are analyzed and conserved in compliance with CEQA requirements.
Goal COS-11 Continue to identify and evaluate cultural, historic, archeological, paleontological, and architectural resources for protection from demolition and inappropriate actions.
Policy COS-11.1 Identify and protect historic and cultural resources including individual properties, districts, and sites (e.g., archaeological sites) in compliance with CEQA.
Policy COS-11.2 Prohibit the demolition or removal of a historic structure without evaluation of the condition of the structure, the cost of rehabilitation, and the feasibility of alternatives to preservation in place including but not limited to relocation, or reconstruction offsite, and/or photopreservation.
Policy COS-11.3 Identify opportunities for adaptive reuse of historic sites and buildings to preserve and maintain their viability.
Mills Act
The Mills Act Historical Property Contract Program allows qualifying owners to receive a potential property tax reduction and use the savings to help rehabilitate, restore, and maintain their buildings. The Mills Act is the single most important economic incentive program in California for the restoration and preservation of historic buildings by private property owners. Enacted in 1972, the Mills Act legislation grants participating local governments (cities and counties) authority to enter into contracts with owners of qualified historic properties who actively participate in the restoration and maintenance of their properties to receive property tax relief.
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The City of San Marcos authorized the creation of a Mills Act Program in 2005 (Resolution 2005- 6539) for the preservation of historically significant properties.
1.3.3 Native American Traditional Cultural Properties
Native American Heritage Values
Federal and state laws mandate that consideration be given to the concerns of contemporary Native Americans with regard to potentially ancestral human remains associated funerary objects and items of cultural patrimony. Consequently, an important element in assessing the significance of the study site has been to evaluate the likelihood that these classes of items are present in areas that would be affected by the proposed project.
Also, potentially relevant to prehistoric archaeological sites is the category termed Traditional Cultural Properties in discussions of cultural resources management performed under federal auspices. According to Parker and King (1998), “Traditional” in this context refers to those beliefs, customs, and practices of a living community of people that have been passed down through the generations, usually orally or through practice. The traditional cultural significance of a historic property, then, is significance derived from the role the property plays in a community’s historically rooted beliefs, customs, and practices. Examples of properties possessing such significance include the following:
1. A location associated with the traditional beliefs of a Native American group about its origins, its cultural history, or the nature of the world;
2. A rural community whose organization, buildings and structures, or patterns of land use reflect the cultural traditions valued by its long-term residents;
3. An urban neighborhood that is the traditional home of a particular cultural group, and that reflects its beliefs and practices;
4. A location where Native American religious practitioners have historically gone, and are known or thought to go today, to perform ceremonial activities in accordance with traditional cultural rules of practice; and
5. A location where a community has traditionally carried out economic, artistic, or other cultural practices important in maintaining its historic identity.
A Traditional Cultural Property, then, can be defined generally as one that is eligible for inclusion in the NRHP because of its association with cultural practices or beliefs of a living community that (a) are rooted in that community’s history and (b) are important in maintaining the continuing cultural identity of the community.
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2.0 GUIDELINES FOR DETERMINING IMPACT SIGNIFICANCE
For the purposes of this technical report, any of the following will be considered a potentially significant environmental impact to cultural resources:
1. The project causes a substantial adverse change in the significance of a historical resource pursuant to §15064.5.
2. The project causes a substantial adverse change in the significance of an archaeological resource pursuant to §15064.5.
3. The project disturbs any human remains, including those interred outside of formal cemeteries.
Guidelines 1 and 2 are derived directly from CEQA. Sections 21083.2 of CEQA and 15064.5 of the CEQA Guidelines recommend evaluating historical and archaeological resources to determine whether or not a proposed action would have a significant effect on unique historical or archaeological resources. Guideline 3 is included because human remains must be treated with dignity and respect, and CEQA requires consultation with the “Most Likely Descendant” as identified by the NAHC for any project in which human remains have been identified.
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3.0 ANALYSIS OF PROJECT EFFECTS
3.1 Methods
3.1.1 Survey Methods
The goal of this survey was to provide a constraints-level survey to identify the location of any cultural resource that may be present on site. Harris & Associates archaeologist Robert Bolger, RPA, and junior archaeologist Jasmine Alvarez-Ceja conducted the survey on April 4, 2023.
Records searches were conducted for the project site and a 0.5-mile buffer. In addition, the NAHC was contacted for a Sacred Lands File check. Tribes were invited to participate in the survey; however, none of the Tribes requested to be involved within the 30-day response period.
The San Luis Rey Band of Mission Indians’ request for a Luiseño Native American monitor be involved in the survey if it had not already been conducted was received after the 30-day response period.
The field survey was conducted using standard archaeological procedures and techniques, which included close interval transects to make up for a lack of ground visibility in much of the survey area. The survey area included the 1.1 combined acres of parcels 220-140-05-00, 220-140-06-00, and 220-140-16-00. Continuous 3-meter parallel transects were walked in an east–west orientation.
The northern parcels of the survey consisted of a vacant lot in an otherwise developed area that was heavily overgrown with vegetation that severely limited visibility to less than 4 percent.
The parcel did show signs of significant bioturbation from ground squirrel activity whose burrows accounted for almost all areas of clear ground visibility. The southern parcel, containing a known historical resource (two buildings), was closely surveyed throughout all open areas for potential unidentified resources before a detailed evaluation of the exterior of both buildings was conducted.
Refer to Sections 3.2 and 4.1 for results and significance determination.
The survey area was photographed (Appendix A, Photographs) to document the environmental setting and existing status of the historical resource. A California DPR Continuation Sheet was completed for the known historical resource (P-37-014081) (Appendix C, DPR Forms).
The updated DPR form was submitted to the SCIC.
3.1.2 Laboratory and Cataloging Procedures
All cultural material assessed during the survey was evaluated in the field and left in place.
No individual artifacts were identified, and the cultural materials evaluated consisted of two historic buildings that had been previously documented and assessed in 1994. Updated DPR forms were completed for the on-site structures. Copies of DPR forms have been submitted to the SCIC.
3.1.3 Artifact Conveyance
No artifacts were identified during the survey.
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3.1.4 Native American Participation/Consultation
Harris contacted the NAHC on January 19, 2023, for a Sacred Lands File check to determine whether sacred lands are present on site. The NAHC response was negative for resources and recommended that the list of Tribes provided be contacted for more information. All Tribal bands on the list provided by the NAHC were contacted for any information they may have regarding Sacred Sites that may be present on site (Confidential Appendix D, Sacred Lands File Check and Tribal Outreach).
Five Tribes (Barona Group of Capitan Grande, Jamul Indian Village, Rincon Band of Luiseño Indians, San Luis Rey Band of Mission Indians, and Viejas Band of Kumeyaay Indians) responded to the outreach efforts. The Barona Group of Capitan Grande responded on March 27, 2023, requesting to be informed of any identified resources. Jamul Indian Village also responded (March 10, 2023) and deferred to San Pasqual Band of Diegueño Mission Indians.
The Rincon Band of Luiseño Indians responded on March 9, 2023, and identified that the project site is within the Tribe’s Traditional Use Area. They researched their database, and no known Tribal Cultural Resources or Traditional Cultural Properties were identified. However, the Rincon Band of Luiseño Indians did identify a post-contact structure. They requested to consult directly with the lead agency regarding project impacts and requested a copy of the final study.
The San Luis Rey Band of Mission Indians responded on April 26, 2023, that they are traditionally and culturally affiliated (TCA) with the area of San Marcos. They identified that there are cultural sites within proximity to the project. They requested that caution be used in assessing the project, and that a Luiseño Native American monitor be present during all ground-disturbing activities.
The San Luis Rey Band of Mission Indians requested that they be provided with a copy of the study and, if the survey has not been completed, that a Luiseño Native American monitor be a part of the survey. The survey was conducted on April 4, 2023, after the 30-day response period and before the request was received from San Luis Rey Band of Mission Indians.
Viejas Band of Kumeyaay Indians responded on March 15, 2023, identifying that the project site has cultural significance or ties to the Tribe and that cultural resources have been located within or adjacent to the project site. They requested that a monitor be on site for ground-disturbing activities and that they be informed of any inadvertent discoveries. They identified that they have monitors available; however, if a Tribe in closer proximity to the project requests to perform monitoring, the Viejas Band of Kumeyaay Indians will defer to them.
3.2 Results
No new cultural materials were located during a detailed survey of the area. A known historic resource (P-37-014081) consisting of two buildings associated with the San Marcos Forest Fire Station were re-evaluated to assess their current historical value.
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4.0 INTERPRETATION OF RESOURCE IMPORTANCE AND
IMPACT IDENTIFICATION
4.1 Resource Importance
4.1.1 Archaeological Resources
No prehistoric or historic archaeological resources were encountered on the survey.
4.1.2 Historic Resources
The known historic resource (P-37-014081) was re-evaluated by Harris to assess the status of its current historical integrity. The structures have modern additions, modifications, and damage that has impacted the historic integrity.
The site consists of two buildings, one garage and one barrack, both originally built in 1939, that serviced the San Marcos Forest Fire Station. Both buildings have been boarded up and been without necessary maintenance and upkeep for some time prior to the 2023 re-evaluation.
The re-evaluation found that both structures are in notable disrepair, extensively damaged by vandalism and the elements, and have undergone significant modernization prior to abandonment that changed the outward appearance and historical character of the resource. Specific issues with the structures are provided below:
1. Both buildings show significant dilapidation, with severely peeling paint throughout, modern spray paint graffiti, the asphalt roof disintegrating on the south-facing sides, the flashing and fascia of the eaves being mostly missing, multiple locations of exterior cladding either damaged or completely removed, and the in-ground sign and mailbox area having been destroyed. In addition, the rear porch roof of the barracks is collapsing due to a now-missing vertical support beam.
2. Numerous examples of modern additions, added before disuse of the property, also impact the historic character of the structures, including:
a) Both the barracks and the garage have been updated with modern exterior lights. b) The south face of the garage has been updated with a modern surface-mounted ½ inch PVC water line servicing a modern eyewash station near the west end of the building and a 1 ½ inch water output and standard ½ inch hose spigot along the east end of the building. c) The west side of the garage has a modern, surface-mounted electrical service running into a trench cut through the concrete, connecting it to the barracks. d) Both the barracks and the garage display surface-mounted modern low-voltage services and junction boxes surface mounted to the side of the buildings. e) The south side of the barracks (prominently) displays a modern sprinkler control system surface-mounted to the side of the building.
f) The north side of the barracks displays a surface-mounted modern circuit breaker box and electrical service, replacing the original fuse-box service still located on the west side of the structure.
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g) The east (front) face of the barracks has an attached and prominent modern radio antenna atop a pole made of modern interior fire sprinkler piping. h) The garage has a modern garage door that replaced the original.
The combination of visible damage (including spray paint graffiti, missing or damaged exterior cladding and fascia, a collapsing rear porch roof, and a destroyed entrance sign/mailbox area) and obvious modern upgrades (including a plastic eyewash station, surface-mounted PVC water lines, modern lighting, modern electrical and sprinkler control systems, modern radio antenna, and modern garage door) were found to significantly decrease the historical importance of the resource.
4.1.3 Native American Heritage Resources/Traditional Cultural Properties No information has been obtained from Native American outreach. No Traditional Cultural Properties that currently serve religious or other community practices are known to exist within the project site. During the current archaeological evaluation, no artifacts or remains were identified or recovered that could be reasonably associated with such practices.
4.2 Impact Identification
No previously unrecorded resources were located within the survey area. The on-site structures will be demolished; however, they are not significant historic resources. Due to the very poor visibility in the northern parcels and the possibility of additional subsurface historic resources in the southern parcel, it is recommended that a construction monitoring program be implemented that includes that both an archaeological monitor and a TCA Native American monitor be engaged to provide monitoring for earth-disturbing activities.
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5.0 MANAGEMENT CONSIDERATIONS –
MITIGATION MEASURES AND DESIGN CONSIDERATIONS
Due to the poor visibility and sensitivity of the area, it is recommended that both an archaeological monitor and a TCA Native American monitor be engaged to provide monitoring for earthdisturbing activities during project construction. Harris recommends that all staff complete a Worker’s Environmental Awareness Program (WEAP) training prior to the start of ground disturbance for the project and archaeological and Native American monitoring take place during initial project-related ground disturbance. In addition, the City has an agreement with the Tribes to include a Pre-Excavation Agreement, construction monitoring, unanticipated discovery procedures, and human remain procedures as mitigation measures. Mitigation measures are discussed below.
5.1 Worker’s Environmental Awareness Training
A qualified archaeologist should be retained to conduct WEAP training on archaeological sensitivity for all construction personnel prior to the commencement of any ground-disturbing activities. The archaeologist should meet or exceed the Secretary of the Interior’s professional qualifications standards for archaeology (NPS 1983). Archaeological sensitivity training should include a description of the types of cultural material that may be encountered, cultural sensitivity issues, regulatory issues, and the proper protocol for treatment of the materials in the event of a find.
5.2 Pre-Excavation Agreement
Details of the Pre-Excavation Agreement are provided below:
• A Pre-Excavation Agreement is required by the City as a mitigation measure and must be satisfied prior to issuance of a Grading Permit or ground disturbance. The Pre-Excavation Agreement requires that the applicant/owner enter into an agreement with a TCA Native American Tribe to formalize protocols and procedures to be followed for the protection, treatment, and repatriation of Native American human remains, funerary objects, cultural and/or religious landscapes, ceremonial items, traditional gathering areas, and other Tribal Cultural Resources. Such resources may be located within and/or discovered during grounddisturbing and/or construction activities for the proposed project, including any additional culturally appropriate archaeological studies, excavations, geotechnical investigations, grading, preparation for wet and dry infrastructure, and other ground-disturbing activities.
Any project-specific Monitoring Plans and/or Excavation Plans prepared by the project archaeologist shall include the TCA Tribe requirements for protocols and protection of Tribal Cultural Resources that were agreed to during the Tribal consultation. • The landowner is required to relinquish ownership of all non-burial related Tribal Cultural Resources collected during construction monitoring and from any previous archaeological studies or excavations on the project site to the TCA Tribe for proper treatment and disposition per the Pre-Excavation Agreement, unless ordered to do otherwise by the responsible agency or court of competent jurisdiction. The requirement and timing of such release of ownership, and the recipient thereof, shall be reflected in the Pre-Excavation Archaeological and Historic Resources
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Agreement. If the TCA Tribe does not accept the return of the cultural resources, then the cultural resources shall be subject to curation.
5.3 Construction Monitoring
Details of construction monitoring are provided below:
• Prior to the issuance of a Grading Permit or ground-disturbing activities, the applicant/owner or grading contractor shall provide written documentation (either as signed letters, contracts, or emails) to the City’s Planning Division stating that a qualified archaeologist and TCA Native American monitor have been retained at the applicant/owner or grading contractor’s expense to implement the construction monitoring program, as described in the Pre-Excavation Agreement.
• The qualified archaeologist and TCA Native American monitor shall be invited to attend all applicable pre-construction meetings with the general contractor and/or associated subcontractors to present the construction monitoring program. The qualified archaeologist and TCA Native American monitor shall be present on site during grubbing, grading, trenching, and/or other ground-disturbing activities that occur in areas of native soil or other permeable natural surfaces that have the potential to unearth any evidence of potential archaeological resources or Tribal Cultural Resources. In areas of artificial paving, the qualified archaeologist and TCA Native American monitor shall be present on site during grubbing, grading, trenching, and/or other ground-disturbing activities that have the potential to disturb more than 6 inches below the original pre-project ground surface to identify any evidence of potential archaeological or Tribal Cultural Resources. No monitoring of fill material, existing or imported, shall be required if the general contractor or developer can provide documentation to the satisfaction of the City that all fill materials being used at the site are either (1) from existing commercial (previously permitted) sources of materials or (2) are from private or other non-commercial sources that have been determined to be absent of Tribal Cultural Resources by the qualified archaeologist and TCA Native American monitor.
• The qualified archaeologist and TCA Native American monitor shall maintain ongoing collaborative coordination with one another during all ground-disturbing activities. The requirement for the construction monitoring program shall be noted on all applicable construction documents, including demolition plans and grading plans. The applicant/owner or grading contractor shall provide written notice to the Planning Division and the TCA Tribe, preferably through email, of the start and end of all ground-disturbing activities. • Prior to the release of any grading bonds, or prior to the issuance of any project Certificate of Occupancy, an Archaeological Monitoring Report, which describes the results, analysis, and conclusions of the construction monitoring, shall be submitted by the qualified archaeologist, along with any TCA Native American monitor’s notes and comments received by the qualified archaeologist, to the Planning Division Manager for approval. Once approved, a final copy of the Archaeological Monitoring Report shall be retained in a confidential City project file and may be released, as a formal condition of Assembly Bill 52 consultation, to a TCA Tribe or any parties involved in the project-specific monitoring or consultation process. A final copy of the report, with all confidential site records and appendices, shall also be submitted to the South Coastal Information Center after approval by the City.
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5.4 Unanticipated Discoveries
Details of unanticipated discoveries protocols and procedures are provided below:
• Both the qualified archaeologist and the TCA Native American monitor may temporarily halt or divert ground-disturbing activities if potential archaeological resources or Tribal Cultural Resources are discovered during construction activities. Ground-disturbing activities shall be temporarily directed away from the area of discovery for a reasonable amount of time to allow a determination of the resource’s potential significance. Isolates and clearly non-significant archaeological resources (as determined by the qualified archaeologist, in consultation with the TCA Native American monitor) shall be minimally documented in the field. All unearthed archaeological resources or Tribal Cultural Resources shall be collected, temporarily stored in a secure location (or as otherwise agreed upon by the qualified archaeologist and the TCA Tribe), and repatriated according to the terms of the Pre-Excavation Agreement, unless ordered to do otherwise by responsible agency or court of competent jurisdiction.
• If a determination is made that the archaeological resources or Tribal Cultural Resources are considered potentially significant by the qualified archaeologist, the TCA Tribe, and the TCA Native American monitor, then the City and the TCA Tribe shall determine, in consultation with the applicant/owner and the qualified archaeologist, the culturally appropriate treatment of those resources.
• If the qualified archaeologist, the TCA Tribe, and the TCA Native American monitor cannot agree on the significance or mitigation for such resources, these issues shall be presented to the Planning Division manager for decision. The Planning Division manager shall make a determination based upon the provisions of CEQA and California Public Resources Code, Section 21083.2(b), with respect to archaeological resources and California Public Resources Code, Sections 21704 and 21084.3, with respect to Tribal Cultural Resources, and shall take into account the religious beliefs, cultural beliefs, customs, and practices of the TCA Tribe.
• All sacred sites, significant Tribal Cultural Resources, and/or unique archaeological resources encountered on the project site shall be avoided and preserved as the preferred mitigation. If avoidance of the resource is determined to be infeasible by the City as the lead agency, then the City shall require additional culturally appropriate mitigation to address the negative impact to the resource, such as, but not limited to, the funding of an Ethnographic Study and/or a Data Recovery Plan, as determined by the City in consultation with the qualified archaeologist and the TCA Tribe. The TCA Tribe shall be notified and consulted regarding the determination and implementation of culturally appropriate mitigation and the drafting and finalization of any Ethnographic Study and/or Data Recovery Plan, and/or other culturally appropriate mitigation. Any archaeological isolates or other cultural materials that cannot be avoided or preserved in place as the preferred mitigation shall be temporarily stored in a secure location on site (or as otherwise agreed upon by the qualified archaeologist and TCA Tribe) and repatriated according to the terms of the Pre-Excavation Agreement, unless ordered to do otherwise by responsible agency or court of competent jurisdiction. The removal of any artifacts from the project site shall be inventoried with oversight by the TCA Native American monitor.
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• If a Data Recovery Plan is authorized as indicated above and the TCA Tribe does not object, then an adequate artifact sample to address research avenues previously identified for sites in the area shall be collected using professional archaeological collection methods.
If the qualified archaeologist collects such resources, the TCA Native American monitor must be present during any testing or cataloging of those resources. Moreover, if the qualified archaeologist does not collect the cultural resources that are unearthed during the ground-disturbing activities, the TCA Native American monitor may, at their discretion, collect said resources for later reburial or storage at a local curation facility, as described in the Pre-Excavation Agreement.
• In the event that curation of archaeological resources or Tribal Cultural Resources is required by a superseding regulatory agency, curation shall be conducted by an approved local facility within San Diego County and the curation shall be guided by California State Historical Resources Commission’s Guidelines for the Curation of Archaeological Collections. The City shall provide the applicant/owner final curation language and guidance on the project grading plans prior to issuance of the grading permit, if applicable, during project construction. The applicant/owner shall be responsible for all repatriation and curation costs and provide to the City written documentation from the TCA Tribe or the curation facility, whichever is most applicable, that the repatriation and/or curation have been completed.
5.5 Human Remains
Details of human remains protocols and procedures are provided below:
• As specified by California Health and Safety Code, Section 7050.5, if human remains, or remains that are potentially human, are found on the project site during ground-disturbing activities or during archaeological work, the person responsible for the excavation, or their authorized representative, shall immediately notify the San Diego County Medical Examiner’s Office by telephone. No further excavation or disturbance of the discovery or any nearby area reasonably suspected to overlie adjacent remains (as determined by the qualified archaeologist and/or the TCA Native American monitor) shall occur until the medical examiner has made the necessary findings as to origin and disposition pursuant to California Public Resources Code, Section 5097.98.
• If such a discovery occurs, a temporary construction exclusion zone shall be established surrounding the area of the discovery so that the area would be protected (as determined by the qualified archaeologist and/or the TCA Native American monitor), and consultation and treatment could occur as prescribed by law. As further defined by state law, the medical examiner shall determine within 2 working days of being notified if the remains are subject to their authority. If the medical examiner recognizes the remains to be Native American, and not under their jurisdiction, then they shall contact the NAHC by telephone within 24 hours. The NAHC shall make a determination as to the most likely descendent, who shall be afforded 48 hours from the time access is granted to the discovery site to make recommendations regarding culturally appropriate treatment. • If suspected Native American remains are discovered, the remains shall be kept in situ (in place) until after the medical examiner makes their determination and notifications and until after the most likely descendent is identified, at which time the archaeological Archaeological and Historic Resources
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examination of the remains shall only occur on site in the presence of the most likely descendent. The specific locations of Native American burials and reburials shall be proprietary and not disclosed to the general public. According to California Health and Safety Code, six or more human burials at one location constitute a cemetery (Section 8100), and disturbance of Native American cemeteries is a felony (Section 7052). In the event that the applicant/owner and the most likely descendant are in disagreement regarding the disposition of the remains, state law shall apply, and the mediation process shall occur with the NAHC. In the event that mediation is not successful, the landowner shall rebury the remains at a location free from future disturbance (refer to California Public Resources Code, Sections 5097.98[e] and 5097.94[k]).
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6.0 REFERENCES
Bean, Lowell John and Florence Shipek. 1978. “Luiseño.” Handbook of North American Indians Vol 8. California. Edited by R.F. Heizer. Smithsonian Institution, Washington D.C.
Campbell, Leon G. 1977. “The Spanish Presidio in Alta California During the Mission Period 1769–1784.” Journal of the West 16(4):63–77.
Carrico, Richard L. 1977. Archaeological/Historical Survey of the Oaks North Villa PRD/Bernardo Trails No. 5 Projects. Unpublished manuscript on file at the South Coastal Information Center.
Carrico, Richard L. 1986. “Before the Strangers: American Indians in San Diego at the Dawn of Contact.” In The Impact of European Exploration and Settlement on Local Native Americans. San Diego: Cabrillo Historical Association. 5–12.
Chartkoff, Joseph L., and Kerry Kona Chartkoff. 1984. The Archaeology of California. Stanford:
Stanford University Press.
Christenson, Lynne E. 1992. “The Late Prehistoric Yuman Settlement and Subsistence System:
Coastal Adaptation.” In Essays on the Prehistory of Maritime California. Terry L. Jones, ed. Davis: University of California, Davis, Center for Archaeological Research. 217–230.
City of San Marcos. 2012. General Plan. Accessed July 2023. https://www.sanmarcos.net/home/showpublisheddocument/8482/636570702255970000.
Cline, Lora L. 1979. The Kwaaymii: Reflections on a Lost Culture. El Centro: Imperial Valley Museum.
Costo, Jeanette Henry. 1987. “The Sword and the Cross: The Missions of California.” In The Missions of California: A Legacy of Genocide. Rupert Costo and Jeanette Henry Costo, eds. San Francisco: Indian Historian Press. 49–66.
Erlandson, Jon M., and Roger H. Colton. 1991. “An Archaeological Context for Early Holocene Studies on the California Coast.” In Hunter-Gatherers of the Early Holocene Coastal California. Jon M. Erlandson and Roger H. Colton, eds. Los Angeles: University of California, Los Angeles, Institute of Archaeology. 1–10.
Gallegos, Dennis. 1995. Cultural Resource Phase I Boundary Test for the Jamul Shopping Center Project. Unpublished manuscript on file at the County of San Diego, Planning and Development Services.
Griner, E. Lee, and Philip R. Pryde. 1976. “Climate, Soils, and Vegetation.” In San Diego: An Introduction to the Region. Edited by Philip R. Pryde. 4th edition. Kendall/Hunt Publishing Company. Dubuque, Iowa. 29–46.
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Hale, Micah, Brad Comeau, Adrienne Dorrler, and Adam Giacinto. 2018. Cultural Resources Report for the Newland Sierra Project, San Diego County, California. Unpublished manuscript on file at the County of San Diego, Planning and Development Services.
Jackson, Robert H., and Edward Castillo. 1995. Indians, Franciscans, and Spanish Colonization:
The Impact of the Mission System on California Indians. Albuquerque: University of New Mexico Press.
Kaldenberg, Russell L. 1976. “Paleo-Technological Change at Rancho Park North, San Diego County, California.” Master’s thesis, San Diego State University.
Kroeber, A.L. 1925. Handbook of the Indians of California: Bureau of American Ethnology Bulletin 78. Smithsonian Institution, Washington D.C.
Masters, Patricia M., and Dennis R. Gallegos. 1997. “Environmental Change and Coastal Adaptations in San Diego County During the Middle Holocene.” In Archaeology of the California Coast During the Middle Holocene. Jon Erlandson and Michael Glassow, eds.
Los Angeles: University of California, Los Angeles, Institute of Archaeology. 11–22.
Moratto, Michael. 1984. California Archaeology. San Francisco: Academic Press.
Moriarty, James R. 1967. “Transitional Pre-Desert Phase in San Diego County, California.” Science 155:553–556.
NETR (Nationwide Environmental Title Research, LLC) Online. 2023. Historic Aerials. Accessed July 2023. http://www.historicaerials.com.
NPS (National Park Service). 1983. Archaeology and Historic Preservation: Secretary of Interior’s Standards and Guidelines. Accessed July 2023 – https://www.nps.gov/subjects/historicpreservation/upload/standards-guidelinesarcheology-historic-preservation.pdf.
Parker, Patricia L., and Thomas F. King. 1998. Guidelines for Evaluating and Documenting Traditional Cultural Properties. U.S. Department of the Interior, National Park Service, National Register, History and Education, National Register of Historic Places. 1990, revised 1992.
Phillips, George H. 1981. The Enduring Struggle: Indians in California History. San Francisco:
Boyd and Fraser Publishing Company.
Rogers, Malcolm. 1939. San Diego Museum Papers No. 3. San Diego: San Diego Museum of Man.
Rogers, Malcolm. 1966. Ancient Hunters of the Far West. San Diego: Copley Press.
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Shipek, F.C. 1993. “Kumeyaay Plant Husbandry: Fire Water, and Erosion Management Systems.” In Before the Wilderness: Native American Environmental Management. Thomas C.
Blackburn and Kat Anderson, eds. Menlo Park: Ballena Press. 78–388.
Sparkman, Philip S. 1908. “The Culture of the Luiseno Indians.” University of California Publications in Archaeology and Ethnology 8(4): 187-234.
Taylor, R.E., and Clement Meighan. 1978. Chronologies in New World Archaeology. New York:
Academic Press.
Thornton, Mark. 1994. A Survey and Historic Significance Evaluation of the CDF Building Inventory. Unpublished manuscript on file with the South Coastal Information Center, San Diego.
True, Delbert. L. 1958. “An Early Complex in San Diego County, California.” American Antiquity 23(3):255–263.
True, Delbert. L. 1966. “Archaeological Differentiation of Shoshonean and Yuman Speaking Groups in Southern California.” PhD. diss. University of California, Los Angeles.
True, Delbert. L. 1970. Investigation of a Late Prehistoric Complex in the Cuyamaca Rancho State Park, San Diego County, California. Los Angeles: University of California, Los Angeles, Department of Anthropology, Archaeological Survey Monograph.
Wahoff, Tanya, and Christy Dolan. 2000. Environmental Assessment for the Rincon San Luiseño Band of Mission Indians, Rincon Casino. Unpublished manuscript on file at the County of San Diego, Planning and Development Services.
Wallace, William J. 1955. “A Suggested Chronology for Southern California Coastal Archaeology.” Southwestern Journal of Anthropology 11:214–230.
Wallace, William J. 1978. “Post-Pleistocene Archaeology, 9000–2000 B.C.” In Handbook of North American Indians. Vol. 8. Robert F. Heizer, ed. Washington, DC: Smithsonian Institution. 25–36.
Warren, Claude N., and D.L. True. 1961. UCLA Archaeological Annual Survey Reports, 1960– 1961. Los Angeles: University of California, Los Angeles.
Warren, Claude N., D.L. True, and A. Eudy. 1961. “Early Gathering Complexes if Western San Diego County.” In University of California, Los Angeles, Archaeological Annual Survey Reports, 1960–1961. Los Angeles: University of California, Los Angeles.
Weather U.S. 2023. Climate and Monthly Weather Forecast for San Marcos, CA. Accessed July 2023. https://www.weather-us.com/en/california-usa/san marcos-climate.
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7.0 LIST OF PREPARERS AND PERSONS AND ORGANIZATIONS CONTACTED The following persons participated in the preparation of this report:
Harris & Associates
Donna Beddow Principal Investigator
Robert Bolger Archaeologist
Jasmine Alvarez-Ceja Junior Archaeologist
The following agencies, organizations, and individuals were contacted:
Native American Heritage Commission
South Coastal Information Center
Raymond Welch Barona Group of Capitan Grande
Ralph Goff Campo Band of Diegueño Mission Indians
Michael Garcia Ewiiaapaayp Band of Kumeyaay Indians
Robert Pinto Ewiiaapaayp Band of Kumeyaay Indians
Virgil Perez Iipay Nation of Santa Ysabel
Clint Linton Iipay Nation of Santa Ysabel
Rebecca Osuna Inaja-Cosmit Band of Indians
Erica Pinto Jamul Indian Village
Lisa Cumper Jamul Indian Village
Carmen Lucas Kwaaymii Laguna Band of Mission Indians
Norma Contreras La Jolla Band of Luiseño Indians
Javaughn Miller La Posta Band of Diegueño Mission Indians Gwendolyn Parada La Posta Band of Diegueño Mission Indians Angela Elliott Santos Manzanita Band of Kumeyaay Nation Michael Linton Mesa Grande Band of Diegueño Mission Indians Shasta Gaughen, Ph.D. Pala Band of Mission Indians
Temet Aguilar Pauma Band of Luiseño Indians
Mark Macarro Pechanga Band of Indians
Paul Macarro Pechanga Band of Indians
Cheryl Madrigal Rincon Band of Luiseño Indians
Bo Mazzetti Rincon Band of Luiseño Indians
Cami Mojado San Luis Rey Band of Mission Indians
Allen Lawson San Pasqual Band of Diegueño Mission Indians John Flores San Pasqual Band of Diegueño Mission Indians Joseph Ontiveros Soboba Band of Luiseño Indians
Isaiah Vivanco Soboba Band of Luiseño Indians
Cody Martinez Sycuan Band of the Kumeyaay Nation
Kristie Orosco Sycuan Band of the Kumeyaay Nation
John Christman Viejas Band of Kumeyaay Indians
Ernest Pingleton Viejas Band of Kumeyaay Indians
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8.0 LIST OF MITIGATION MEASURES AND DESIGN CONSIDERATIONS The following mitigation measures and design considerations will serve to mitigate project impacts to below a level of significance.
Site No. Direct Impacts Mitigation Measures Design Considerations P-37-014081 Yes None – Not a significant
resource
None – Not a significant
resource
Unidentified Buried
Resources
Unknown Pre-Excavation
Agreement,
Construction Monitoring,
Unanticipated Discoveries
Human Remains
Appendix A. Photographs
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Photograph 1: Northern parcels.
Photograph 2: Southern parcel.
Photograph 3: Barracks, east elevation (front).
Photograph 4: Barracks, west elevation (rear), graffiti, collapsed porch roof.
Photograph 5: Barracks, west elevation, missing/damaged exterior cladding.
Photograph 6: Barracks, south elevation, modern irrigation system.
Photograph 7: Garage, south elevation, collapsed and missing fascia.
Photograph 8: Garage, east elevation, modern garage door.
Appendix B. CHRIS Background Data
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Appendix C. DPR Forms
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age of *Resource Name or # (Assigned by recorder)
*Recorded by: *Date Continuation
Update
DPR 523L (9/2013
State of California - The Resources Agency Primary# 37-014081 DEPARTMENT OF PARKS AND RECREATION HRI #
Trinomial
CONTINUATION SHEET
Property Name:_San Marcos Forest Fire Station_______________________________________________________________ Page of _____
A reevaluation of the exteriors of the buildings of P-37-014081 conducted in 2023 found that many modern additions, modifications, and damages have impacted the historic nature and appearance of the both the Barracks and the Garage elements of the site.
These elements include:
1. Both buildings have had all windows and doors boarded up with plywood due to planned disuse of the buildings.
2. Both building show significant dilapidation, with severely peeling paint throughout, modern spray paint graffiti, the asphalt roof disintegrating on the south-facing sides, the flashing and fascia of the eaves being mostly missing, multiple locations of exterior cladding either damaged or completely removed, and the in-ground sign and mailbox area having been destroyed. In addition, the rear porch roof of the Barracks is collapsing due to a now-missing vertical support beam.
3. Numerous examples of modern additions added before disuse of the property also impact the historic character of the structures, including:
a) Both the Barracks and the Garage buildings have been updated with modern exterior lights b) The south face of the garage has been updated with a modern surface-mounted ½” PVC water line servicing a modern eyewash station near the west end of the building and a 1 ½” water output and standard ½” hose spigot along the east end of the building. c) The west side of the garage has a modern, surface mounted electrical service running into a trench cut through the concrete, connecting it to the Barracks. d) Both the Barracks and the Garage display surface-mounted modern low voltage services and junction boxes surface mounted to the side of the buildings. e) The south side of the Barracks (prominently) displays a modern sprinkler control system surface-mounted to the side of the building.
f) The north side of the Barracks displays a surface-mounted modern circuit breaker box and electrical service, replacing the original fuse box service still located on the west side of the structure.
g) The Barracks east (front) face of the Barracks building has an attached and prominent modern radio antenna atop a pole made of modern interior fire sprinkler piping. age of *Resource Name or # (Assigned by recorder)
*Recorded by: *Date Continuation
Update
DPR 523L (9/2013
State of California - The Resources Agency Primary# 37-014081 DEPARTMENT OF PARKS AND RECREATION HRI #
Trinomial
CONTINUATION SHEET
Property Name:_San Marcos Forest Fire Station_______________________________________________________________ Page of _____
East (front) entrance to Barracks. Boarded windows, fading paint, damaged roof, and modern radio antenna shown.
South entrance to Garage. Modern surface-mounted eye wash station visible. age of *Resource Name or # (Assigned by recorder)
*Recorded by: *Date Continuation
Update
DPR 523L (9/2013
State of California - The Resources Agency Primary# 37-014081 DEPARTMENT OF PARKS AND RECREATION HRI #
Trinomial
CONTINUATION SHEET
Property Name:_San Marcos Forest Fire Station_______________________________________________________________ Page of _____
West (rear) face of Barracks showing both modern graffiti and collapsing rear porch roof.
South face of Barracks showing modern surface-mounted sprinkler controller system. age of *Resource Name or # (Assigned by recorder)
*Recorded by: *Date Continuation
Update
DPR 523L (9/2013
State of California - The Resources Agency Primary# 37-014081 DEPARTMENT OF PARKS AND RECREATION HRI #
Trinomial
CONTINUATION SHEET
Property Name:_San Marcos Forest Fire Station_______________________________________________________________ Page of _____
West (rear) face of Barracks with significant missing/damaged exterior cladding.
Front signage and mailbox area now in disrepair and overgrown.
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Appendix D. Geotechnical Investigation
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GLOBAL GEO-ENGINEERING, ING.
February 16, 2023
Project 9421-04
DMS Consultants, Inc.
12377 Lewis Street, Suite 203
Garden Grove, California 92840
Attention: Mr. Surender Dewan, P. E.
President
Subject: Geotechnical Investigation
Proposed Multi-Family Residential Development
236 and 244 Pico Avenue
San Marcos, California
References: See Appendix A
Dear Mr. Dewan:
1. INTRODUCTION
a) In accordance with your request, we have conducted a geotechnical investigation for the proposed residential development located in San Marcos, California. b) We understand that the proposed development will consist of the construction of four 3-story, multi-family residential structures, each unit approximately 1,170- squarefoot, with related parking/driveway areas on a 0.67-acre parcel of land. In addition, an infiltration system is planned to be installed for potential stormwater runoff.
c) Grading and structural plans are not available at present. We are assuming that the existing grades will remain unchanged. We anticipate the loads from the proposed structures will not exceed 3 kip/ft for the continuous footings and 50 kips for the column footings.
2. SCOPE
The scope of services we provided were as follows:
a) Preliminary planning and evaluations, and review of geotechnical reports related to the project site and nearby surrounding area (See References — Appendix A); 3 Corporate Park, Suite 270, Irvine, California 92606 Office (949) 221-0900 Fax (949) 221-0091 Email: [email protected] DMS Consultants, Inc.
February 16, 2023
Project 9421-04
b)
)
d)
g
Excavation of three (3) borings utilizing a hollow stem auger drill rig to a maximum depth of 40 feet below ground surface. One of the borings was drilled to a depth of 5 feet below ground surface for the purpose of percolation testing; Sampling and logging of subsurface materials encountered in the borings; Field percolation testing to determine the infiltrations rate; Laboratory testing of samples representative of those obtained in the field, in order to evaluate relevant engineering properties;
Engineering and geologic analyses of the field and laboratory data; Preparation of a report presenting our findings, conclusions and recommendations.
FIELD EXPLORATION AND LABORATORY TESTING
The field exploration program is given in Appendix B, which includes the Logs of Borings.
The results of the laboratory testing are included in Appendix C.
SITE DESCRIPTION
4.1 42
Location
a) The project site is located along the southwest side of Pico Avenue, approximately 280 feet northwest of San Marcos Boulevard, in the city of San Marcos, California.
b) The approximate site location is shown on the Location Map, Figure 1.
Existing Surface Conditions
a) The subject property is currently vacant and void of any building structures. b) The ground surface throughout the project site is relatively level. The natural topography of the site area descends to the south at an approximate gradient of one percent.
c); Surface drainage consists of sheet flow runoff of incident rainfall water derived primarily within the property boundaries and adjacent properties.
LOCAT. 10N
BT TR
BASE MAP: USGS 7.5-Minute Topographic Map,
San Marcos Quadrangle, 1999
2000 0 2000 4000
SCALE FEET
GLOBAL GEO-ENGINEERING, INGC.
244 Pico Avenue
San Marcos, California
GEOLOGIC AND SOILS ENGINEERING IRVINE, CALIFORNIA Date: February 2023 Project No.: 9421-04
Figure No:
1 DMS Consultants, Inc.
February 16, 2023
Project 9421-04
43 44
Geology
4.3.1 Regional Geologic Setting
The subject property is located within the Peninsular Ranges Geomorphic Province of California. The Peninsular Ranges consist of a series of mountain ranges separated by longitudinal valleys. The ranges trend northwest-southeast and are sub parallel to faults branching from the San Andreas Fault. The Peninsular Ranges extend from the southern side of the Santa Monica and San Gabriel Mountains into Baja California, Mexico (CDMG, 1997).
Local Geologic Setting
In general, the project site area is underlain by Recent- to Older-aged alluvial deposits which overlie granitic bedrock.
Subsurface Conditions
a)
b)
4.4.1 The subsurface conditions, as encountered in our explorations, are described in the following sections.
More detailed descriptions of the subsurface conditions are presented in our Logs of Borings, which are enclosed as Figures B-2 through B-4 in Appendix B. The locations of the borings are shown on our Boring Location Plan, Figure B-5.
Alluvium
a) Alluvial deposits were encountered in all of our borings excavated on-site.
b) The alluvium was found to generally consist of interlayers of Silty SAND, SAND and Sandy to Clayey SILT.
c) The Silty SAND and SAND sediments were generally found to be fine to coarse grained, slightly moist to very moist and medium dense.
d) The Sandy to Clayey SILT deposits were observed to be slightly moist to moist and stiff.
DMS Consultants, Inc.
February 16, 2023
Project 9421-04
5. Bedrock
a) Bedrock, classified as Tonalite, was encountered at a depth of 37 feet below ground surface in Boring B-1.
b) The bedrock encountered in our boring was noted to be fine textured and hard.
Groundwater
a) Groundwater was encountered in our deeper boring (Boring B-1) at a depth of 24 feet below ground surface. The static water level was measured at a depth of 23.5 feet below ground surface approximately 30 minutes after termination of drilling.
b) No nearby groundwater wells were found to be listed during our review of the California Department of Water Resources internet website.
The property is located in the general proximity of several active and potentially active faults, which are typical for sites in the Southern California region. Earthquakes occurring on active faults within a 70-mile radius are capable of generating ground shaking of engineering significance to the proposed construction.
In Southern California, most of the seismic damage to manmade structures results from ground shaking and, to a lesser degree, from liquefaction and ground rupture caused by earthquakes along active fault zones. In general, the greater the magnitude of the earthquake, greater is the potential damage.
442
443
SEISMICITY
531 General
a)
b)
52 Ground Surface Rupture
a)
b)
The closest known active fault is the Elsinore Fault, located at a distance of about 16.3 miles northeast of the project site. Other nearby active or potentially active faults include the Rose Canyon Fault and the San Jacinto Fault located at distances of about 20.8 miles and 40.8 miles, respectively, from the subject property.
Due to the distance of the closest active fault to the site, ground rupture is not considered a significant hazard at the site.
DMS Consultants, Inc.
February 16, 2023
Project 9421-04
53 5.4
Ground Shaking
a)
b)
We utilized the California Office of Statewide Health Planning and Development (OSHPD) Seismic Design Maps internet program to calculate the peak ground acceleration (PGA) at the project site location.
Using the ASCE 7-16 standard and Site Class D, the PGA at the subject property resulted to be 0.47g.
Figure 2 shows the geographical relationships among the site locations, nearby faults and the epicenters of significant occurrences. The project site is not located within any State of California delineated Earthquake Fault Zone; however, during historic times, a number of major earthquakes have occurred along the active faults in Southern California. From the seismic history of the region and proximity, the Elsinore Fault and Rose Canyon Fault have the greatest potential for causing earthquake damage related to ground shaking at this site.
Liquefaction
The subject site is underlain by dense soil layers overlying a Tonalite bedrock.
The potential for the liquefaction is considered to be low.
6. CONCLUSIONS AND RECOMMENDATIONS
6.1 General
a)
b)
©)
d
It is our opinion that the site will be suitable for the proposed development, from a geotechnical aspect, assuming that our recommendations are implemented.
We are of the opinion that the proposed structures can be supported on shallow spread footings founded in the existing competent soils.
We consider that the anticipated grading will not adversely affect, nor be adversely affected by adjoining property, with due precautions being taken.
The final grading plans and foundation plans/design loads should be reviewed by the Geotechnical Engineer.
The design recommendations in the report should be reviewed during the construction phase.
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February 16, 2023 Project 9421-04
6.2 Grading
6.2.1 622
Processing of On-Site Soils
a)
b)
)
d
e)
To provide uniform support conditions, the subgrade soils should be overexcavated to a depth of one foot below the foundation bottom and three feet below the slab-on-grade, subject to review during construction. The overexcavation should laterally extend for adistance of 5 feet.
There should be at least one foot of reworked soils or compacted fill below the pavements.
Wherever structural fills are to be placed, the upper 6 to 8 inches of the subgrade should, after stripping or overexcavation, first be scarified, reworked and wetted down thoroughly.
Any loosening of reworked or native material, consequent to the passage of construction traffic, weathering, etc., should be made good prior to further construction.
The depths of overexcavation should be reviewed by the
Geotechnical Engineer during the actual construction. Any surface or subsurface obstructions, or questionable material encountered during grading should be brought immediately to the attention of the Geotechnical Engineer for proper exposure, removal or processing as directed. No underground obstructions or facilities should remain in any structural areas. Depressions and/or cavities created as a result of the removal of obstructions should be backfilled properly with suitable material, and compacted.
Material Selection
After the site has been stripped of any debris, vegetation and organic soils, excavated on-site soils are considered satisfactory for reuse in the construction of on-site fills, with the following provisions:
a)
b)
)
Significant water will be required to be added to the existing soils; The organic content does not exceed 3 percent by volume; Large size rocks greater than 8 inches in diameter should not be incorporated in compacted fill;
DMS Consultants, Inc.
February 16, 2023
Project 9421-04
6213
6.2.4 6.2.5
6.2.6 d) Rocks greater than 4 inches in diameter should not be incorporated in compacted fill to within one foot of the underside of the footings and slabs.
Compaction Requirements
a) Reworking/compaction shall include moisture-conditioning as needed to bring the soils to slightly above the optimum moisture content. All reworked soils and structural fills should be densified to achieve at least 90 percent relative compaction with reference to laboratory compaction standard. The optimum moisture content and maximum dry density should be determined in the laboratory in accordance with ASTM Test Designation D1557.
b) Fill should be compacted in lifts not exceeding 8 inches (loose).
Excavating Conditions
a) Excavation of on-site materials may be accomplished with standard earthmoving or trenching equipment. No hard rock was encountered which will require blasting.
b) Ground water was encountered at a depth of 24 feet below ground surface in our deeper boring. Dewatering is not anticipated in excavations shallower than 24 feet below ground surface.
Shrinkage
For preliminary earthwork calculation, an average shrinkage factor of approximately 5 percent is recommended for the soils (this does not include handling losses).
Expansion Potential
a) Based upon our visual observations, the expansion potential for the on-site soils is considered to be medium. The recommendations provided in the following sections will reduce the effects of the expansive subgrade soils.
b) Any imported material, or doubtful material exposed during grading, should be evaluated for its expansive properties. c) In any event, the subgrade soils should be tested for their expansion potential or during the final stages of grading.
DMS Consultants, Inc.
February 16, 2023
Project 9421-04
6.2.7 6.2.8
6.2.9 6.2.10
Sulphate Content
a) The sulphate contents of representative samples of the soil are less than 0.1%. The sulphate exposure is considered to be negligible.
Type 11 Portland cement is recommended for the construction. a) The fill materials should be tested for their sulphate content during the final stage of rough grading.
Utility Trenching
a) The walls of temporary construction trenches in fill should stand nearly vertical, with only minor sloughing, provided the total depth does not exceed 3 feet (approximately). Shoring of excavation walls or flattening of slopes may be required, if greater depths are necessary.
b) Trenches should be located so as not to impair the bearing capacity or to cause settlement under foundations. As a guide, trenches should be clear of a 45-degree plane, extending outward and downward from the edge of foundations. Shoring should comply with Cal-OSHA regulations.
c) Existing soils may be utilized for trenching backfill, provided they are free of organic materials.
d) All work associated with trench shoring must conform to the state and federal safety codes.
Surface Drainage Provisions
Positive surface gradients should be provided adjacent to the buildings to direct surface water run-off away from structural foundations and to suitable discharge facilities.
Grading Control
All grading and earthwork should be performed under the observation of a Geotechnical Engineer in order to achieve proper subgrade preparation, selection of satisfactory materials, placement and compaction of all structural fill. Sufficient notification prior to stripping and earthwork construction is essential to make certain that the work will be adequately observed and tested.
DMS Consultants, Inc.
February 16, 2023
Project 9421-04
6.3 Slab-on-Grade
a) Concrete floor slabs may be founded on the reworked existing soils or compacted fill.
b) The slab should be underlain by four inches of granular material. A plastic vapor barrier is recommended to be placed at the mid-height of the base layer.
c) It is recommended that #4 bars on 12-inch center, both ways, or equivalent be provided as minimum reinforcement in slabs-on-grade. Joints should be provided and slabs supporting no vehicular traffic should be at least 5 inches thick.
d) The FFL should be at least 6 inches above highest adjacent grade. e) The subgrade soils should be kept moist prior to the concrete pour.
6.4 Spread Foundations
The proposed structures can be founded on shallow spread footings. The criteria presented as follows should be adopted:
6.4.1 Dimensions/Embedment Depths
g - o Minimum Footing Minimum Embedment INITIUEROS I || AT A Thickness Below Lowest Finished Surface (floors supported) (ft.) : (in.) (ft.) 3 s 3 Perin.—neter 2.5
Interior 2.5
Square Column Footings 2 . 25
To 50 kip
6.4.2 Allowable Bearing Capacity
Embedment Depth ‘Allowable Bearing Capacity
(ft.) (Ib/ft?)
1.0 2,000
(Notes:
o The allowable bearing capacity may be increased by 800 Ib/ft for each additional foot increase in the depth or by 200 Ib/ft® he width to a maximum value of 4,000 Ib/ft?;
DMS Consultants, Inc.
February 16, 2023
Project 9421-04
6.4.3 These values may be increased by one-third in the case of shortduration loads, such as induced by wind or seismic forces; At least 2x#4 bars should be provided in wall footings, one on top and one at the bottom;
In the event that footings are founded in structural fills consisting of imported materials, the allowable bearing capacities will depend on the type of these materials, and should be re-evaluated;
Bearing capacities should be re-evaluated when loads have been obtained and footings sized during the preliminary design; Planter areas should not be sited adjacent to walls;
Footing excavations should be observed by the Geotechnical Engineer; Footing excavations should be kept moist prior to the concrete pour; It should be insured that the embedment depths do not become reduced or adversely affected by erosion, softening, planting, digging, etc.) Settlements
Total and differential settlements under spread footings are expected to be within tolerable limits and are not expected to exceed 1 and ¥ inches in a horizontal distance of 40 feet, respectively.
6.5 a)
Lateral Pre: ssures
The following lateral pressures are recommended for the design of retaining structures.
Pressure (Ib/ft*/ft depth)
Lateral Force Soil Profile Unrestrained Wall Rigidly Supported Wall Active Pressure Level 36 =
At-Rest Pressure Level - 65
Passive Resistance - am B
(ignore upper 1.5 ft. )
DMS Consultants, Inc.
February 16, 2023
Project 9421-04
b)
)
d)
Friction coefficient: 0.35 (includes a Factor of Safety of 1.5). While combining friction with passive resistance, reduce passive by 1/3.
These values apply to the existing soil, and to compacted backfill generated from in-situ material. Imported material should be evaluated separately. It is recommended that where feasible, imported granular backfill be utilized, for a width equal to approximately one-quarter the wall height, and not less than 1.5 feet.
Backfill should be placed under engineering control.
Subdrains comprised of 4-inch perforated SDR-35 or equivalent PVC pipe covered in a minimum of one cubic foot per linear foot of filter rock and wrapped in Mirafi 140N filter fabric should be provided behind retaining walls.
6.6 Seismic Coefficients and Liquefaction Potential
a) For seismic analysis of the proposed project in accordance with the seismic provisions of ASCE 7-16, we recommend the following:
ITEM VALUE
Site Latitude (Decimal-degrees) 33.14197
Site Longitude (Decimal-degrees) -117.16598
Site Class D
Risk Category 1l
Mapped Spectral Response Acceleration-Short Period (0.2 Sec) - Ss 0.897 Mapped Spectral Response Acceleration-1 Second Period — S 0.33 Short Period Site Coefficient-F, 1.141
Long Period Site Coefficient F, 1.90
Adjusted Spectral Response Acceleration @ 0.2 Sec. Period (Sms) 1.024 Adjusted Spectral Response Acceleration @ 1Sec.Period (Smi) 0.627 Design Spectral Response Acceleration @ 0.2 Sec. Period (Sps) 0.682 Design Spectral Response Acceleration @ 1-Sec. Period (Spi) 0.418 b) Ground water was encountered at a depth of 24 feet below ground surface, however, the subject site is underlain by dense soil layers. The potential for liquefaction is considered to be low.
DMS Consultants, Inc.
February 16, 2023
Project 9421-04
6.7 Pavement Design
6.7.1 Asphalt Pavement Section
a) Based on Traffic Indices (T.I) and on the anticipated “R” — Value of 42 of the subgrade, the following tentative structural pavement sections are recommended.
6.7:2
6.73 6.7.4
Poeation T Asphs{lic Concrete Aggr_egme Base
(inches) (inches)
Parking and Driveways Upto 5.0 3 4
Driveway (light truck traffic) 60 g 4
b) The subgrade soils should be tested for R-Value at the conclusion of rough grading and the pavement sections should be finalized then.
Subgrade Preparation
Subgrade soils within the upper 12 inches of finished grade shall be moisture-conditioned where necessary, shall be compacted to at least 90 percent relative compaction per ASTM D1557, and shall be free of any loose or soft areas.
Base Preparation
Unless otherwise specified, the base shall consist of Class II %-inch aggregate base or approved Crushed Miscellaneous Base. The base shall be compacted to a minimum of 95 percent relative compaction in accordance with the procedures described in ASTM Test Method D1557.
Concrete Pavement
If proposed, the concrete pavement should be at least 5 inches thick, reinforced with #4 bars on 12 inches center bothways, underlain by 4 inches thick base as recommended above. Thicker concrete section will be required for traffic greater than T.I. of 6.0.
6.8 Corrosion Potential
a) Soil Corrosion potential for metal and concrete was estimated by performing water-soluble sulfate, chloride, pH, and electrical resistivity tests during this investigation.
DMS Consultants, Inc.
February 16, 2023
Project 9421-04
b) Electrical resistivity is a measure of soil resistance to the flow of corrosion currents. Corrosion currents are generally high in low resistivity soils.
The electrical resistivity of a soil decreases primarily with an increase in its chemical and moisture contents.
A commonly accepted correlation between electrical resistivity and corrosivity for buried ferrous metals is presented below:
L Electrical Resistivity, Ohm-cm Corrosion Potential =| Less than 1,000 Severe
1,000-2,000 Corrosive
2,000-10,000 Moderate Greater than 10,000 Mild
d) Results of electrical resistivity test indicate a value of 3,339 ohm-cm for the near-surface soils. Based on this data, it is our opinion that, in general, on-site near-surface soils are considered moderately corrosive in nature.
This potential should be considered in design of underground metal pipes.
6.9 Percolation Study
a)
b)
A borehole percolation tests as outlines in San Marcos BMP design manual, appendix D, section D.3.2.2 was used to conduct percolation testing.
Approximate location of Boring P-1 as shown on the boring location plan enclosed as Figure B-5. The filed percolation rate can be converted to 20 minutes/inch.
The soils in the upper 5 feet were Clayey Silty SAND underlain by Silty SAND/Sandy SILT. We recommend the basin to be at least 6 feet deep.
As more granular soils are anticipated at that depth, we estimate the following infiltration rate. During the grading operation, a percolation test should be conducted to verify the infiltration rate.
Boring No. Percolation Rate (inch/hour)
P-1 3.0
d) These rates are calculated using a factor of safety of 1.0. Appropriate factor of safety should be utilized while designing the basin.
DMS Consultants, Inc.
February 16, 2023
Project 9421-04
7. LIMITATIONS
a)
b)
Soils and bedrock over an area show variations in geological structure, type, strength and other properties from what can be observed, sampled and tested from specimens extracted from necessarily limited exploratory borings. Therefore, there are natural limitations inherent in making geologic and soil engineering studies and analyses. Our findings, interpretations, analyses and recommendations are based on observation, laboratory data and our professional experience; and the projections we make are professional judgments conforming to the usual standards of the profession. No other warranty is herein expressed or implied.
In the event that during construction, conditions are exposed which are significantly different from those described in this report, they should be brought to the attention of the Geotechnical Engineer.
The opportunity to be of service is sincerely appreciated. If you have any questions or if we can be of further assistance, please call.
Very truly yours,
RGE 2301
(Exp. March 31, 2023)
Principal Engineerin@iGis ist
CEG 2253
(Exp. October 31, 2023)
MBU/KBY: fdg
Enclosures:
Location Map - Figure 1
Seismicity Map - Figure 2
References - Appendix A
Field Exploration - Appendix B
Unified Soils Classification System Figure B-1
Logs of Borings
Boring Location Plan
Laboratory Testing
Figures B-2 through B-4
Figure B-5
- Appendix C
Project 9421-04
APPENDIX A
References
California Geological Survey, Earthquake Fault Zones of Required Investigation, (Internet).
California Division of Mines and Geology, 1996, Geologic Maps of the Northwestern Part of San Diego County, California, CDMG Open File Report 96-02.
California Office of Statewide Health Planning and Development, Seismic Design Maps Web Tool, ASCE 7-16 Standard (Internet).
United States Geological Survey, 1948, San Marcos Quadrangle, 7.5-Minute Topographic Series.
United States Geological Survey, 1968, San Marcos Quadrangle, 7.5-Minute Topographic Series.
United States Geological Survey, 1968 photorevised 1983, San Marcos Quadrangle, 7.5- Minute Topographic Series.
a)
b)
)
d
e)
Project 9421-04
APPENDIX B
Field Exploration
The site was explored on May 17, 2022, utilizing a B-61 Mobile hollow stem drill rig to excavate three borings to a maximum depth of 40 feet below the existing ground surface.
One of the borings were subsequently backfilled. Three-inch diameter perforated pipe with gravel rock encasement was installed in Boring P-1 for the purpose of percolation testing The soils encountered in the excavations were logged and sampled by our Engineering Geologist. The soils were classified in accordance with the Unified Soil Classification System described in Figure B-1. The Logs of Borings are presented in Figures B-2 through B-4. The approximate locations of the borings are shown on the Boring Location Plan, Plate
1. The logs, as presented, are based on the field logs, modified as required from the results of the laboratory tests. Driven ring and bulk samples were obtained from the excavations for laboratory inspection and testing. The depths at which the samples were obtained are indicated on the logs.
The number of blows of the driving weight during sampling was recorded, together with the depth of penetration, the driving weight and the height of fall. The blows required per foot of penetration for given samples was then calculated and shown on the logs.
Groundwater was encountered at a depth of 24 feet below ground surface in Boring B-1.
Caving occurred in all of the borings to the depths noted on the logs.
UNIFIED SOILS CLASSIFICATION (ASTM D-2487)
PRIMARY DIVISION GROUP SYMBOL SECONDARY DIVISIONS
” . G?:vaef"s GW Well graded gravels, gravel-sand mixture, little o no fines = 1] 23 g 2 8 @ E B58| (<5% fines) GP Poorly graded gravels or gravel-sand mixtures, little or no fines 7R >E£82 agg P % Gravel with GM Silty gravels, gravel-sand-silt mixture. Non-plastic fines. Wwes ©Os5°38¢8 zES 2 8= Fines £58 , & GC Clayey gravels, gravel-sand-clay mixtures. Plastic fines [ 8 t§ 5, Clean Sands sw Well-graded gravels, gravel-sand mixtures, little or no fines. § Qet |[Bce ¥/ % 5 |SEs GS%iines) sp Poorly graded sands or gravelly sands, litle or o fines. 55 |38 IS 28 |5 235 Sands with SM Silty sands, sand-silt mixtures. Non-Plastic fines. = Fines sc Clayey sands, sand-clay mixtures. Plastic fines. . £2 ML Inorganic silts and very fine sands, rock flour, silty or clayey fine 28 2, £t sands or clayey silts, with slight plasticity 3 kS g ;‘)E 3 g cL Inorganic clays of low to medium plasticity, gravelly clays, sandy 582 23 59 clays, silty clays, lean clays. ATl 2° g4 aE2 @« Sa oL Organic silts and organic silty clays of low plasticity. o' s T z28 s Ex MH Inorganic silts, micaceous or diatomaceous fine sandy or silty & * 2o 2¢8 soils, elastic silts. 5 x| &=l o§E 23 o é z CH Inorganic clays of high plasticity, fat clays we 5o 36% 8 7° BoF % g E & S50 OH Organic clays of medium to high plasticity, organic silts = - . K Highly Organic Soils PT Peat and other highly organic soils. ighly
CLASSIFICATION BASED ON FIELD TESTS
PENETRATION RESISTANCE (PR) Clays and Silts
*Numbers of blows of 140 Ib hammer Sands and Gravels Consistency Blows/foot* Strength** falling 30 inches to drive a 2-inch O.D. g (13/8 in. 1.D.) Split Barrel sampler Relative Density Blows/foot Very Soft 0-2 0% (ASTM-1568 Standard Penetration Test) Very loose 04 Soft 24 Yt Loose 410 Firm 48 % - - = E **Unconfined Compressive strength in | Medium Dense 10-30 Stiff 8-15 12 tons/sq. ft. Read from pocket Dense 30-50 Very Stiff 15-30 24 penetrometer Very Dense Over 50 Hard Over 30 Over 4
CLASSIFICATION CRITERIA BASED ON LAB TESTS
GW and SW — C,= Dgo/D1o greater than 4 for GW and 6 for SW; C. = (Do) 2/D1ox Dgo between 1 and 3 GP and SP - Clean gravel or sand not meeting requirement for GW and SW GM and SM — Atterberg limit below “A” line or P.1. less than 4 Plasticity Index
!
GC and SC — Atterberg limit above “A” line P.1. greater than 7 K
0 10 2 3 40 50 @ M s 9 w0 CLASSIFICATION OF EARTH MATERIAL IS BASED ON FIELD INSPECTION Liquid Limit AND SHOULD NOT BE CONSTRUED TO IMPLY LABORATORY ANALYSIS o UNLESS SO STATED. ion of Fine-grained soils
Fines (Silty or Clay) Fine Sand | Medium Sand | Coarse Sand | Fine Gravel | Coarse Gravel | Cobbles | Boulders Sieve Sizes 200 40 10 4 w B 10"
244 Pico Avenue
GLOBAL GEO-ENGINEERING, INC. SanMacos Califomis
GEOLOGIC AND SOILS ENGINEERING, IRVINE, CALIFORNIA Date: February 2023 Figure No.:
Project No.: 9421-04 B-1
) ) Drilling Method Hollow Stem Global Geo-Engineering, Inc. LOG OF BORING B-1 Sampling Method ~ : California Modiified Irvine, California Hammer Weight (Ibs) : 140 Geologists and Geotechnical Engineers Hammer Drop (in) 30 Date May 17, 2022 244 Pico Avenue Logged By KBY
San Marcos, California Diameter of Boring 6" Driling Company Cal Pac Drilling Driling Rig Mobile B-61 Project 9421-04
i Sample Type Water Levels
2 51 Ring W Groundwater Encountered
= vz g [Z4 Buk 7 Seepage Encountered 8 28|z.1z2| 8 |= B Standard Penetration Testing 2 3<|5] o |3 o < o |83 [ 20| 3 o |8 I s |2|22|1853|2| 2 |5 @ T 5 |E[Zc| 8| e 13} < g laleslzs| 2 sl g z DESCRIPTION [ Clayey Silty SAND: fine to medium grained, light reddish brown, | ’ slightly moist, medium dense /4 18 SM "/:{ 76 | 1167 | 55
1 Silty SAND: fine grained, yellow brown, slightly moist, medium dense with SILT interbeds
6.8 112.6 29
1 SM/ML
x 129 | 1162 | 100 10
1 Clayey SILT: light reddish to reddish brown, slightly moist to moist, 40 stiff 1 V’,‘ P 150 | 1155 | 39 7%
1 ML
. @19' moist IX 19.3 | 1006 | 38 20
] v m 150 | 1154 | 23 sp SAND: medium to coarse grained, reddish brown, very moist to 25 . . wet, medium dense, water encountered Figure B-2.1
. " Drilling Method : Hollow Stem Global Geo-Engineering, Inc. LOG OF BORING B-1 Sampiing Method : Calfornia Mocified Irvine, California Hammer Weight (Ibs) : 140 Geologists and Geotechnical Engineers Hammer Drop (in) ~ :30 Date : May 17, 2022
244 Pico Avenue Logged By :KBY San Marcos, California Diameter of Boring ~: 6" Drilling Company : Cal Pac Drilling
Drilling Rig * Mobile B-61 Project 9421-04
_ Sample Type Water Levels
2 5] Ring W Groundwater Encountered - v g [Z2 Buk 7 Seepage Encountered fid 28|28 | 8 |3 o B Standard Penetration Testing £ o |83 (20| 3 o |3 I = 2228382 2 |% @ T
a El5|25|828| o LR[S | @ T 2 |2 |8 =) 8 5] g DESCRIPTION 25 1 sP
N 19.5 106.0 18 a X
4 SPIML
J @34’ medium grained, olive brown
& 17.2 104.9 12 35
1 ALLUVIUM
1 TONALITE: fine textured, hard ] N GR
] 91 | 1203 | 100 BASEMENT ROCK
40 Bottom of Boring at 40 feet
il Notes: ] 1. aving to 23 feet ater augers were removed 2. Water encountered at 24', Static water level measured at 23.5' ] 3. Boring backfilled 45 50|
Figure B-2.2
Global Geo-Engi . Drilling Method Hollow Stem obal Geo-Engineering, Inc. LOG OF BORING B-2 Sampling Method ~ : California Modified Irvine, California Hammer Weight (Ibs) : 140 Geologists and Geotechnical Engineers Hammer Drop (in) ~ :30 Date May 17, 2022 244 Pico Avenue Logged By 1KBY San Marcos, California Diameter of Boring ~: 6" Drillng Company : Cal Pac Drilling Driling Rig Mobile B-61 Project 9421-04
_ Sample Type Water Levels
-%’ X Ring W Groundwater Encountered 8 5 vz g [ZA Buk 7 Seepage Encountered i 22|28 | 8 |32 B Standard Penetration Testing 2 Z=|5| o |& ) Sl 1822503 ¢ |3 2 s 222|882 2 |5 = z S glE[35|=228|2| |8 |E2x|&s|a| & 8 |2 (3] 8 2 F 5 DESCRIPTION 0 Sandy Silty CLAY: reddish brown, slightly moist, medium stff with | Clayey SILT interbeds CuUML
185 | 1138 | 20
Sandy SILT: yellow to light reddish brown, slightly moist, stiff 110 [ 1072 | 45 ML
112 | 1125 | 35 @9' with Silty SAND interbeds
MLU/SM
Clayey SILT: olive gray to light reddish brown, slightly maist, stift & 140 | 1142 | 48 15+
ML
Clayey Silty SAND: fine to medium grained, light reddish brown, moist, medium dense ALLUVIUM M 120 | 1134 | 20 SM 20 Bottom of Boring at 20 feat:
Notes: 1 1. Caving to 15.5 feet after augers were removed 2. No groundwater or seepage encountered 4 3. Boring backfilled 25—
Figure B-3
. N Drilling Method Hollow Stem Global Ge_0~Eng!fleeflng, Inc. LOG OF BORING P-1 Sampling Method ~ : California Modified Irvine, California Hammer Weight (Ibs) : 140 Geologists and Geotechnical Engineers Hammer Drop (in) ~ : 30 Date : May 17, 2022 244 Pico Avenue Logged By {KBY, San Marcos, California Diameter of Boring 8" Drilling Company : Cal Pac Drilling
Drilling Rig : Mobile B-61
Project 9421-04
_ Sample Type Water Levels
2 = Ring W Groundwater Encountered & _ vz 3 74 Buk Z_ Seepage Encountered 8 2 § ze| e 8 g o B Standard Penetration Testing < ] 25| 3 = = |8]22(85(S| 2 |5 = F a Els|25|53|28| o R |o8| @ T 3 |2 |8 > 8 o g DESCRIPTION 0 ] Clayey Sity SAND: fine grained, reddish brown, slightly moist, d medium dense SM
| ALLUVIUM
& Bottom of Boring at 5 feet:
i Notes: d 1. No groundwater or seepage encountered 2. 3-inch perforated pipe installed; Pipe encased with 3/4-inch ] diameter gravel rock 10|
15 20—
25 Figure B-4
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Project 9421-04
APPENDIX C
Laboratory Testing Program
The laboratory-testing program was directed towards providing quantitative data relating to the relevant engineering properties of the soils. Samples considered representative of site conditions were tested as described below.
a)
b)
Moisture and Density
Moisture-density information usually provides a gross indication of soil consistency.
Local variations at the time of the investigation can be delineated, and a correlation obtained between soils found on this site and nearby sites. The dry unit weights and field moisture contents were determined for selected samples. The results are shown on the Logs of Borings.
Compaction
A representative soil sample was tested in the laboratory to determine the maximum dry density and optimum moisture content, using the ASTM D1557 compaction test method.
This test procedure requires 25 blows of a 10-pound hammer falling a height of 18 inches on each of five layers, in a 1/30 cubic foot cylinder. The results of the test are presented below.
Optimum - 8 Maximum Boring No. SampleDepth Soil Deseription pIoOare Dry Density (ft.) Content Ib/ft ) i) B-1 13 Clayey Silty SAND 9.9 127.3
Appendix C
Project 9421-04
) Direct Shear
Direct shear tests were made on remolded samples, using a direct shear machine at a constant rate of strain. Variable normal or confining loads are applied vertically and the soil shear strengths are obtained at these loads. The angle of internal friction and the cohesion are then evaluated. The samples were tested at saturated moisture contents. The results are shown below in terms of the Coulomb shear strength parameters.
Angle of g Coulomb Boring No. | Stmple Depth Soil Cohesion Internal | posy Residual (ft) Description Friction (b/fe2) e ©) Ho 250 29 Peak B-1 13 Clayey Silty SAND = - i
d) Sulfate Content
A representative soil sample was analyzed for its sulphate content. The results are given below:
. Sample Depth g Aty Sulphate Content Boring No. 7o Soil Description o B-1 13 Clayey Silty SAND 0.0026
e) Chloride Content
A representative soil sample was analyzed for chloride content in accordance with California Test Method CA422. The result is given below:
— Sample Depth Soil Chloride Content Boring No. (i) Description (%) B-1 13 Clayey Silty SAND 0.0023
Appendix C
Project 9421-04
) Resistivity and pH
A representative soil sample was analyzed in accordance with California Test Methods CAS532 and CA643 to determine the minimum resistivity and pH. The result is provided below:
o Minimum Boring No. S""“’(I:t)l)ep‘h oo o pH Resistivity P! (Ohm-cm)
B-1 13 Clayey Silty SAND 8.1 3,339
g) Expansion Potential
Surface soils were collected in the field and tested in the laboratory in accordance with the ASTM Test Designation D4829. The degree of expansion potential is determined from soil volume changes occurring during saturation of the specimen. The results of the tests are presented below:
Sample Depth Soil Expansion Expansion Boring No. (ft) Description Index Potential B-2 2 Sandy Silty CLAY 70 Medium
Appendix E. Project Climate Action Plan Consistency Review Checklist This page intentionally left blank.
Appendix F. Hydromodification Technical Memorandum
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TECHNICAL MEMORANDUM:
SWMM Modeling for
Hydromodification Compliance of:
Pico Place
Prepared For:
DMS Consultants, Inc.
Prepared by:
Luis Parra, PhD, CPSWQ, ToR, D.WRE.
R.C.E. 66377
November 3, 2022
REC Consultants
2442 Second Avenue
San Diego, CA 92101
Telephone: (619) 232-9200
TECHNICAL MEMORANDUM
TO: DMS Consultants, Inc.
FROM: Luis Parra, PhD, PE, CPSWQ, ToR, D.WRE, CFM.
David Edwards, MS, PE, CFM.
DATE: November 3, 2022
RE: Summary of SWMM Modeling for Hydromodification Compliance for Pico Place, San Marcos, CA.
INTRODUCTION
This memorandum summarizes the approach used to model the proposed residential development project site in the City of San Marcos using the Environmental Protection Agency (EPA) Storm Water Management Model 5.0 (SWMM). SWMM models were prepared for the pre and post‐developed conditions at the site in order to determine if the proposed LID facilities have sufficient volume to meet Order R9‐2013‐001 requirements of the California Regional Water Quality Control Board San Diego Region (SDRWQCB), as explained in the Final Hydromodification Management Plan (HMP), dated March 2011, prepared for the County of San Diego by Brown and Caldwell.
SWMM MODEL DEVELOPMENT
The Pico Place project comprises of a multi0family development inclusive of a private drive accessway and vegetated landscaped areas. Two (2) SWMM models were prepared for this study: the first for the pre‐development and the second for the post‐developed conditions. The project site drains to one (1) overall Point of Compliance (POC‐1), located at the existing storm drain system to the eastern boundary of the project site within the adjacent Pico Avenue.
Per Section G.1.2 in Appendix G of the 2016 City of San Marcos’ BMP Design Manual, the EPA SWMM model was used to perform the continuous hydrologic simulation. For both SWMM models, flow duration curves were prepared to determine if the proposed HMP facility is sufficient to meet the current HMP requirements.
The inputs required to develop SWMM models include rainfall, watershed characteristics, and BMP configurations. The Poway gauge from the Project Clean Water website was used for this study, since it is the most representative of the project site precipitation due to elevation and proximity to the project site. Please see gauge location and project location map on Attachment 5.
The Escondido gage is not recommended for continuous simulation because (a) 22% of the intensities higher than 0.4 in/hr have data problems, and (b) the highest intensities measured in this station do not belong to the location of the gage (were copied from Wolford, at an elevation 850 ft higher than Escondido). Similarly, Wohlford data was not used mainly because the difference in elevation. At this point, we decided that the closest gage, with no significant data problems at similar elevation than the project elevation, was the most appropriate, therefore we used Poway precipitation.
Pico Place
November 3, 2022
2 Per the California Irrigation Management Information System “Reference Evaporation Zones” (CIMIS ETo Zone Map), the project site is located within the Zone 6 Evapotranspiration Area. Thus evapotranspiration values for the site were modeled using Zone 9 average monthly values from Table G.1‐1 from the City of San Marcos’ 2016 BMP Design Manual. The site was modeled with type C hydrologic soil per the site‐specific geotechnical report undertaken for the project site (please refer to Attachment 8 of this memo).
Soils have been assumed to be compacted in the existing condition to represent the current developed condition of the site. In the post developed conditions, the soils have been modeled as fully compacted.
Other SWMM inputs for the subareas are discussed in the appendices to this document, where the selection of the parameters is explained in detail.
HMP MODELING
PRE DEVELOPED CONDITIONS
The current property consists on a developed residential site that drains via overland flow to a receiving storm drain system (POC‐1) located within Pico Avenue to the east of the project site. Table 1 below illustrates the pre‐developed area to be developed and impervious percentage accordingly.
TABLE 1 – SUMMARY OF PRE‐DEVELOPED CONDITIONS
POC DMA Tributary Area, A
(Ac)
Impervious Percentage,
Ip(1)
POC‐1 DMA‐1C 0.675 0%
TOTAL ‐‐ 0.675 0%
Notes: (1) – Per the 2013 RWQCB permit, existing condition impervious surfaces are not to be accounted for in existing conditions analysis.
DEVELOPED CONDITIONS
Runoff from the developed project site is drained to one (1) onsite receiving LID Infiltration BMP. Once flows are routed via the proposed LID BMPs, developed onsite flows are then conveyed to the aforementioned POC. Table 2 below summarizes the DMAs for the developed site.
TABLE 2 – SUMMARY OF DEVELOPED CONDITIONS
POC DMA Tributary Area, A
(Ac) Impervious Percentage, Ip
POC‐1 DMA‐1C 0.675 74.79%
TOTAL ‐‐ 0.675 ‐‐
Developed flows from the project site are conveyed to one (1) onsite detention facility prior to discharging to the existing storm drain system. The vault system is approximately 9‐feet deep with a width of 8‐feet and length of 45‐feet. Due to the limited grade on the project site and utility constraints, the vault is to be located several feet below the existing storm drain invert in Pico Avenue such that the vault can only be drained via the use of pumps. Due to HMP criteria, two (2) separate pumps will be employed on the project site, a low flow pump outlet will be located at 3.2 feet from the bottom of the Pico Place
November 3, 2022
3 basin invert while the peak Q100 flow pump will be located at 7.25 feet from the basin invert. A secondary pump will be provided on site should the primary pump fail and in an extreme event, flows will outlet via the surface private drive to Pico Avenue without risk of flooding the residential structures and also providing single vehicular lane access.
Due to the high rate of measured infiltration onsite experienced during the geotechnical investigation, the base of the vault will be unlined such that flows can infiltrate into the underlying base. The filtration basin has been modeled directly as basins within SWMM can have infiltration associated with the base footprint accordingly.
Water Quality BMP Sizing &Drawdown Calculations
It is assumed all storm water quality requirements for the project will be met by the LID BMPs detailed in the SWQMP and other BMPs included within the site design. However, detailed water quality requirements are not discussed within this technical memo. For further information in regards to storm water quality requirements for the project (including sizing and drawdown) please refer to the site‐ specific Storm Water Quality Management Plan (SWQMP).
BMP MODELING FOR HMP PURPOSES
Modeling of HMP BMPs
One (1) LID BMP basin is proposed for hydromodification conformance for the project site. Tables 4 and 5 illustrates the dimensions required for HMP compliance according to the SWMM model that was undertaken for the project. It should be noted that pumps are the only possible outlet structure such that an elevation and flow will be identified for the system.
TABLE 4 – SUMMARY OF BIOFILTRATION / PARTIAL INFILTRATION BMP
BMP DIMENSIONS
Tributary
Area (ft2) Vault Width (ft) Vault Length (ft) Vault Depth (ft) Total VaultVolume (ft3) Vault 30,596 8 45 9 3,240
TABLE 5 – SUMMARY OF OUTLET PUMP DETAILS
BMP
Low Flow Pump Peak Flow Pump
Flow Rate (cfs) Elevation(1) (ft) Flow Rate (cfs) Elevation(1) (ft) Vault 0.02 3.2 1.9 7.25
Notes: (1): Basin ground surface elevation assumed to be 0.00 ft elevation..
Pico Place
November 3, 2022
4 FLOW DURATION CURVE COMPARISON
The Flow Duration Curve (FDC) for the site was compared at the POCs by exporting the hourly runoff time series results from SWMM to a spreadsheet.
Q2 and Q10 were determined with a partial duration statistical analysis of the runoff time series in an Excel spreadsheet using the Cunnane plotting position method (which is the preferred plotting methodology in the HMP Permit). As the SWMM Model includes a statistical analysis based on the Weibull Plotting Position Method, the Weibull Method was also used within the spreadsheet to ensure that the results were similar to those obtained by the SWMM Model.
The range between 10% of Q2 and Q10 was divided into 100 equal time intervals; the number of hours that each flow rate was exceeded was counted from the hourly series. Additionally, the intermediate peaks with a return period “i” were obtained (Qi with i=3 to 9). For the purpose of the plot, the values were presented as percentage of time exceeded for each flow rate. FDC comparison at the POC is illustrated in Figure 1 in both normal and logarithmic scale.
As can be seen in Figure 1, the FDC for the proposed condition with the HMP BMPs is within 110% of the curve for the existing condition in both peak flows and durations. The additional runoff volume generated from developing the site will be released to the existing point of discharge at a flow rate below the 10% Q2 lower threshold for the POC. Additionally, the project will also not increase peak flow rates between the Q2 and the Q10, as shown in the peak flow table in Attachment 1.
Discussion of the Manning’s coefficient (Pervious Areas) for Pre and Post‐Development Conditions Typically, the Manning’s coefficient is selected as n = 0.10 for pervious areas and n = 0.012 for impervious areas. However, due to the impact that n has in the continuous simulation a more accurate value of the Manning’s coefficient has been chosen for pervious areas. Taken into consideration the study prepared by TRWE (Reference [6]) a value of n = 0.05 has been selected (see Table 1 of Reference [6] included in Attachment 7). An average n value between average grass plus pasture (0.04) and dense grass (0.06) has been selected per the reference cited, for light rain (<0.8 in/hr) as more than 99% of the rainfall has been measured with this intensity.
SUMMARY
This study has demonstrated that the proposed HMP BMP provided for the Pico Place site is sufficient to meet the current HMP criteria if the cross‐section areas and volumes recommended within this technical memorandum, and the respective orifice and outlet structure are incorporated as specified within the proposed project site.
Pico Place
November 3, 2022
5 KEY ASSUMPTIONS
1. Type C Soil is representative of the existing condition site. This is based on the site‐specific geotechnical investigation undertaken for the project site.
ATTACHMENTS
1. Q2 to Q10 Comparison Tables
2. FDC Plots (log and natural “x” scale) and Flow Duration Table.
3. List of the “n” largest Peaks: Pre‐Development and Post‐Development Conditions
4. Elevations vs. Discharge Curves to be used in SWMM
5. Pre & Post Development Maps, Project plan and section sketches
6. SWMM Input Data in Input Format (Existing and Proposed Models)
7. SWMM Screens and Explanation of Significant Variables
8. Geotechnical Documentation
9. Summary files from the SWMM Model
REFERENCES
[1] – “Review and Analysis of San Diego County Hydromodification Management Plan (HMP):
Assumptions, Criteria, Methods, & Modeling Tools – Prepared for the Cities of San Marcos, Oceanside & Vista”, May 2012, TRW Engineering.
[2] – “Final Hydromodification Management Plan (HMP) prepared for the County of San Diego”, March 2011, Brown and Caldwell.
[3] ‐ Order R9‐2013‐001, California Regional Water Quality Control Board San Diego Region (SDRWQCB).
[4] – “Handbook of Hydrology”, David R. Maidment, Editor in Chief. 1992, McGraw Hill. [5] – “City of San Marcos BMP Design Manual”, February 2016. [6] – “Improving Accuracy in Continuous Hydrologic Modeling: Guidance for Selecting Pervious Overland Flow Manning’s n Values in the San Diego Region”, TRWE, 2016.
Pico Place
November 3, 2022
6 Figure 1a and 1b. Flow Duration Curve Comparison (logarithmic and normal “x” scale) Pico Place
November 3, 2022
7 ATTACHMENT 1.
Q2 to Q10 Comparison Table – POC 1
Return Period Existing Condition (cfs) Mitigated Condition (cfs) Reduction, Exist ‐ Mitigated (cfs)
2‐year 0.225 0.020 0.205
3‐year 0.270 0.020 0.250
4‐year 0.294 0.020 0.274
5‐year 0.309 0.020 0.289
6‐year 0.339 0.020 0.319
7‐year 0.339 0.020 0.319
8‐year 0.341 0.020 0.321
9‐year 0.363 0.072 0.291
10‐year 0.383 0.137 0.246
ATTACHMENT 2
FLOW DURATION CURVE ANALYSIS
1) Flow duration curve shall not exceed the existing conditions by more than 10%, neither in peak flow nor duration.
The figures on the following pages illustrate that the flow duration curve in post‐development conditions after the proposed BMP is below the existing flow duration curve. The flow duration curve table following the curve shows that if the interval 0.10Q2 – Q10 is divided in 100 sub‐ intervals, then a) the post development divided by pre‐development durations are never larger than 110% (the permit allows up to 110%); and b) there are no more than 10 intervals in the range 101%‐110% which would imply an excess over 10% of the length of the curve (the permit allows less than 10% of excesses measured as 101‐110%).
Consequently, the design passes the hydromodification test.
It is important to note that the flow duration curve can be expressed in the “x” axis as percentage of time, hours per year, total number of hours, or any other similar time variable. As those variables only differ by a multiplying constant, their plot in logarithmic scale is going to look exactly the same, and compliance can be observed regardless of the variable selected.
However, in order to satisfy the City of San Marcos HMP example, % of time exceeded is the variable of choice in the flow duration curve. The selection of a logarithmic scale in lieu of the normal scale is preferred, as differences between the pre‐development and post‐development curves can be seen more clearly in the entire range of analysis. Both graphics are presented just to prove the difference.
In terms of the “y” axis, the peak flow value is the variable of choice. As an additional analysis performed by REC, not only the range of analysis is clearly depicted (10% of Q2 to Q10) but also all intermediate flows are shown (Q2, Q3, Q4, Q5, Q6, Q7, Q8 and Q9) in order to demonstrate compliance at any range Qx – Qx+1. It must be pointed out that one of the limitations of both the SWMM and SDHM models is that the intermediate analysis is not performed (to obtain Qi from i = 2 to 10). REC performed the analysis using the Cunnane Plotting position Method (the preferred method in the HMP permit) from the “n” largest independent peak flows obtained from the continuous time series.
The largest “n” peak flows are attached in this appendix, as well as the values of Qi with a return period “i”, from i=2 to 10. The Qi values are also added into the flow‐duration plot.
0.00 0.020.040.060.080.100.120.140.160.180.200.220.240.260.280.300.320.340.360.380.40
0.001 0.01 0.1
Q (cfs)
Percentage of time exceeded (%)
POC‐1 Pico Place ‐ Flow Duration Curve
ExistingProposedQx
0 0.020.040.060.08
0.1 0.120.140.160.18
0.2 0.220.240.260.28
0.3 0.320.340.360.38
0.4 0 0.02 0.04 0.06
Q (cfs)
Percentage of time exceeded (%)
POC‐1 Pico Place ‐ Flow Duration Curve
ExistingProposedQx
Flow Duration Curve Data for Pico Place POC 1 ‐ San Marcos, CA Q2 = 0.225 cfs Fraction 10 %
Q10 = 0.38 cfs
Step = 0.0036 cfs
Count = 394487 hours
45.00 years
Pass or
Q (cfs) Hours > Q% time Hours>Q % time Post/Pre Fail?
1 0.023 283 7.17E‐02 5 1.27E‐03 2% Pass
2 0.026 262 6.64E‐02 5 1.27E‐03 2% Pass
3 0.030 255 6.46E‐02 5 1.27E‐03 2% Pass
4 0.033 243 6.16E‐02 5 1.27E‐03 2% Pass
5 0.037 229 5.81E‐02 5 1.27E‐03 2% Pass
6 0.041 220 5.58E‐02 5 1.27E‐03 2% Pass
7 0.044 209 5.30E‐02 5 1.27E‐03 2% Pass
8 0.048 199 5.04E‐02 5 1.27E‐03 3% Pass
9 0.052 192 4.87E‐02 5 1.27E‐03 3% Pass
10 0.055 176 4.46E‐02 5 1.27E‐03 3% Pass
11 0.059 171 4.33E‐02 5 1.27E‐03 3% Pass
12 0.063 159 4.03E‐02 5 1.27E‐03 3% Pass
13 0.066 150 3.80E‐02 5 1.27E‐03 3% Pass
14 0.070 138 3.50E‐02 5 1.27E‐03 4% Pass
15 0.073 129 3.27E‐02 5 1.27E‐03 4% Pass
16 0.077 125 3.17E‐02 5 1.27E‐03 4% Pass
17 0.081 118 2.99E‐02 5 1.27E‐03 4% Pass
18 0.084 108 2.74E‐02 5 1.27E‐03 5% Pass
19 0.088 102 2.59E‐02 5 1.27E‐03 5% Pass
20 0.092 95 2.41E‐02 5 1.27E‐03 5% Pass
21 0.095 94 2.38E‐02 5 1.27E‐03 5% Pass
22 0.099 92 2.33E‐02 5 1.27E‐03 5% Pass
23 0.103 89 2.26E‐02 5 1.27E‐03 6% Pass
24 0.106 81 2.05E‐02 5 1.27E‐03 6% Pass
25 0.110 79 2.00E‐02 5 1.27E‐03 6% Pass
26 0.113 73 1.85E‐02 5 1.27E‐03 7% Pass
27 0.117 72 1.83E‐02 5 1.27E‐03 7% Pass
28 0.121 71 1.80E‐02 4 1.01E‐03 6% Pass
29 0.124 69 1.75E‐02 4 1.01E‐03 6% Pass
30 0.128 67 1.70E‐02 4 1.01E‐03 6% Pass
31 0.132 64 1.62E‐02 4 1.01E‐03 6% Pass
32 0.135 61 1.55E‐02 4 1.01E‐03 7% Pass
33 0.139 59 1.50E‐02 4 1.01E‐03 7% Pass
34 0.143 59 1.50E‐02 4 1.01E‐03 7% Pass
35 0.146 57 1.44E‐02 4 1.01E‐03 7% Pass
36 0.150 55 1.39E‐02 4 1.01E‐03 7% Pass
Detention Optimized
Interval
Existing Condition
Pass or
Q (cfs) Hours > Q% time Hours>Q % time Post/Pre Fail?
Detention Optimized
Interval
Existing Condition
37 0.153 55 1.39E‐02 4 1.01E‐03 7% Pass
38 0.157 51 1.29E‐02 4 1.01E‐03 8% Pass
39 0.161 50 1.27E‐02 4 1.01E‐03 8% Pass
40 0.164 46 1.17E‐02 4 1.01E‐03 9% Pass
41 0.168 45 1.14E‐02 4 1.01E‐03 9% Pass
42 0.172 45 1.14E‐02 4 1.01E‐03 9% Pass
43 0.175 43 1.09E‐02 4 1.01E‐03 9% Pass
44 0.179 43 1.09E‐02 4 1.01E‐03 9% Pass
45 0.183 40 1.01E‐02 4 1.01E‐03 10% Pass
46 0.186 40 1.01E‐02 4 1.01E‐03 10% Pass
47 0.190 40 1.01E‐02 4 1.01E‐03 10% Pass
48 0.193 38 9.63E‐03 4 1.01E‐03 11% Pass
49 0.197 38 9.63E‐03 4 1.01E‐03 11% Pass
50 0.201 34 8.62E‐03 4 1.01E‐03 12% Pass
51 0.204 30 7.60E‐03 4 1.01E‐03 13% Pass
52 0.208 29 7.35E‐03 4 1.01E‐03 14% Pass
53 0.212 27 6.84E‐03 4 1.01E‐03 15% Pass
54 0.215 27 6.84E‐03 4 1.01E‐03 15% Pass
55 0.219 27 6.84E‐03 4 1.01E‐03 15% Pass
56 0.223 27 6.84E‐03 4 1.01E‐03 15% Pass
57 0.226 24 6.08E‐03 4 1.01E‐03 17% Pass
58 0.230 24 6.08E‐03 4 1.01E‐03 17% Pass
59 0.233 23 5.83E‐03 4 1.01E‐03 17% Pass
60 0.237 23 5.83E‐03 4 1.01E‐03 17% Pass
61 0.241 21 5.32E‐03 4 1.01E‐03 19% Pass
62 0.244 21 5.32E‐03 4 1.01E‐03 19% Pass
63 0.248 20 5.07E‐03 4 1.01E‐03 20% Pass
64 0.252 20 5.07E‐03 4 1.01E‐03 20% Pass
65 0.255 19 4.82E‐03 4 1.01E‐03 21% Pass
66 0.259 17 4.31E‐03 4 1.01E‐03 24% Pass
67 0.263 16 4.06E‐03 4 1.01E‐03 25% Pass
68 0.266 15 3.80E‐03 4 1.01E‐03 27% Pass
69 0.270 15 3.80E‐03 4 1.01E‐03 27% Pass
70 0.274 14 3.55E‐03 4 1.01E‐03 29% Pass
71 0.277 14 3.55E‐03 4 1.01E‐03 29% Pass
72 0.281 14 3.55E‐03 4 1.01E‐03 29% Pass
73 0.284 12 3.04E‐03 4 1.01E‐03 33% Pass
74 0.288 12 3.04E‐03 4 1.01E‐03 33% Pass
75 0.292 12 3.04E‐03 4 1.01E‐03 33% Pass
76 0.295 10 2.53E‐03 4 1.01E‐03 40% Pass
77 0.299 10 2.53E‐03 4 1.01E‐03 40% Pass
78 0.303 9 2.28E‐03 4 1.01E‐03 44% Pass
79 0.306 9 2.28E‐03 4 1.01E‐03 44% Pass
80 0.310 9 2.28E‐03 4 1.01E‐03 44% Pass
81 0.314 9 2.28E‐03 4 1.01E‐03 44% Pass
Pass or
Q (cfs) Hours > Q% time Hours>Q % time Post/Pre Fail?
Detention Optimized
Interval
Existing Condition
82 0.317 8 2.03E‐03 4 1.01E‐03 50% Pass
83 0.321 8 2.03E‐03 4 1.01E‐03 50% Pass
84 0.324 8 2.03E‐03 4 1.01E‐03 50% Pass
85 0.328 8 2.03E‐03 4 1.01E‐03 50% Pass
86 0.332 8 2.03E‐03 4 1.01E‐03 50% Pass
87 0.335 8 2.03E‐03 4 1.01E‐03 50% Pass
88 0.339 8 2.03E‐03 4 1.01E‐03 50% Pass
89 0.343 5 1.27E‐03 4 1.01E‐03 80% Pass
90 0.346 5 1.27E‐03 4 1.01E‐03 80% Pass
91 0.350 5 1.27E‐03 4 1.01E‐03 80% Pass
92 0.354 5 1.27E‐03 4 1.01E‐03 80% Pass
93 0.357 5 1.27E‐03 4 1.01E‐03 80% Pass
94 0.361 5 1.27E‐03 4 1.01E‐03 80% Pass
95 0.364 5 1.27E‐03 4 1.01E‐03 80% Pass
96 0.368 5 1.27E‐03 4 1.01E‐03 80% Pass
97 0.372 5 1.27E‐03 4 1.01E‐03 80% Pass
98 0.375 5 1.27E‐03 4 1.01E‐03 80% Pass
99 0.379 5 1.27E‐03 4 1.01E‐03 80% Pass
100 0.383 4 1.01E‐03 4 1.01E‐03 100% Pass
Peak Flows calculated with Cunnane Plotting Position
Return Period
(years) Pre‐dev. Q (cfs) Post‐Dev. Q
(cfs)
Reduction
(cfs)
10 0.383 0.137 0.246
9 0.363 0.072 0.291
8 0.341 0.020 0.321
7 0.339 0.020 0.319
6 0.339 0.020 0.319
5 0.309 0.020 0.289
4 0.294 0.020 0.274
3 0.270 0.020 0.250
2 0.225 0.020 0.205
ATTACHMENT 3
List of the “n” Largest Peaks: Pre & Post‐Developed Conditions Basic Probabilistic Equation:
R = 1/P R: Return period (years).
P: Probability of a flow to be equaled or exceeded any given year (dimensionless).
Cunnane Equation: Weibull Equation:
Pൌ ୧ି.ସ
୬ା.ଶ Pൌ ୧୬ାଵ
i: Position of the peak whose probability is desired (sorted from large to small) n: number of years analyzed.
Explanation of Variables for the Tables in this Attachment Peak: Refers to the peak flow at the date given, taken from the continuous simulation hourly results of the n year analyzed.
Posit: If all peaks are sorted from large to small, the position of the peak in a sorting analysis is included under the variable Posit.
Date: Date of the occurrence of the peak at the outlet from the continuous simulation Note: all peaks are not annual maxima; instead they are defined as event maxima, with a threshold to separate peaks of at least 12 hours. In other words, any peak P in a time series is defined as a value where dP/dt = 0, and the peak is the largest value in 25 hours (12 hours before, the hour of occurrence and 12 hours after the occurrence, so it is in essence a daily peak).
List of Peak events and Determination of P2 and P10 (Pre‐Development) Pico Place POC 1 ‐ San Marcos
T
(Year)
Cunnane
(cfs)
Weibull
(cfs)
10 0.38 0.39 Date Posit Weibull Cunnane
9 0.36 0.38 0.155 12/6/1966 45 1.02 1.01
8 0.34 0.35 0.157 2/15/1992 44 1.05 1.04
7 0.34 0.34 0.157 2/8/1993 43 1.07 1.06
6 0.34 0.34 0.158 4/14/2003 42 1.10 1.09
5 0.31 0.31 0.163 4/1/1982 41 1.12 1.11
4 0.29 0.29 0.163 1/9/1998 40 1.15 1.14
3 0.27 0.27 0.174 12/5/1966 39 1.18 1.17
2 0.23 0.23 0.179 11/29/1982 38 1.21 1.20
0.182 2/21/2005 37 1.24 1.23
0.191 2/21/2000 36 1.28 1.27
Note: 0.198 3/8/1974 35 1.31 1.31
Cunnane is the preferred 0.198 1/18/1993 34 1.35 1.35
method by the HMP permit. 0.199 2/17/1998 33 1.39 1.39
0.2 1/4/1995 32 1.44 1.43
0.201 2/6/1976 31 1.48 1.48
0.201 9/10/1976 30 1.53 1.53
0.201 2/16/1980 29 1.59 1.58
0.204 4/21/1988 28 1.64 1.64
0.205 11/16/1972 27 1.70 1.70
0.209 11/23/1965 26 1.77 1.77
0.224 2/27/2001 25 1.84 1.84
0.224 2/12/2003 24 1.92 1.92
0.225 3/17/1963 23 2.00 2.00
0.24 1/29/1980 22 2.09 2.09
0.24 4/18/1995 21 2.19 2.19
0.246 1/6/1979 20 2.30 2.31
0.253 3/1/1983 19 2.42 2.43
0.257 1/9/2005 18 2.56 2.57
0.26 2/8/1983 17 2.71 2.72
0.266 11/30/1982 16 2.88 2.90
0.273 1/7/1974 15 3.07 3.10
0.282 2/28/1970 14 3.29 3.32
0.284 11/12/1976 13 3.54 3.59
0.294 12/18/1978 12 3.83 3.90
0.294 12/29/1978 11 4.18 4.26
0.302 2/14/1998 10 4.60 4.71
0.315 11/5/1987 9 5.11 5.26
0.339 2/3/1998 8 5.75 5.95
0.339 2/8/1998 7 6.57 6.85
0.341 12/29/2004 6 7.67 8.07
0.382 3/17/1982 5 9.20 9.83
0.392 1/10/1978 4 11.50 12.56
0.413 1/25/1995 3 15.33 17.38
0.423 3/24/1983 2 23.00 28.25
0.472 2/21/1980 1 46.00 75.33
Peaks (cfs)
Period of Return
(Years)
List of Peak events and Determination of P2 and P10 (Post‐Development) Cranston POC 1 ‐ Escondido
T
(Year)
Cunnane
(cfs)
Weibull
(cfs)
10 0.14 0.22 Date Posit Weibull Cunnane
9 0.07 0.11 0.02 2/9/1963 45 1.02 1.01
8 0.02 0.04 0.02 2/9/1963 44 1.05 1.04
7 0.02 0.02 0.02 2/9/1963 43 1.07 1.06
6 0.02 0.02 0.02 2/9/1963 42 1.10 1.09
5 0.02 0.02 0.02 2/10/1963 41 1.12 1.11
4 0.02 0.02 0.02 2/10/1963 40 1.15 1.14
3 0.02 0.02 0.02 2/10/1963 39 1.18 1.17
2 0.02 0.02 0.02 2/10/1963 38 1.21 1.20
0.02 2/10/1963 37 1.24 1.23
0.02 2/10/1963 36 1.28 1.27
Note: 0.02 2/10/1963 35 1.31 1.31
Cunnane is the preferred 0.02 2/10/1963 34 1.35 1.35
method by the HMP permit. 0.02 2/11/1963 33 1.39 1.39
0.02 2/11/1963 32 1.44 1.43
0.02 2/11/1963 31 1.48 1.48
0.02 2/11/1963 30 1.53 1.53
0.02 2/11/1963 29 1.59 1.58
0.02 2/11/1963 28 1.64 1.64
0.02 3/17/1963 27 1.70 1.70
0.02 3/17/1963 26 1.77 1.77
0.02 3/17/1963 25 1.84 1.84
0.02 3/17/1963 24 1.92 1.92
0.02 3/17/1963 23 2.00 2.00
0.02 11/21/1963 22 2.09 2.09
0.02 11/21/1963 21 2.19 2.19
0.02 11/16/1965 20 2.30 2.31
0.02 11/16/1965 19 2.42 2.43
0.02 11/16/1965 18 2.56 2.57
0.02 11/16/1965 17 2.71 2.72
0.02 11/17/1965 16 2.88 2.90
0.02 11/17/1965 15 3.07 3.10
0.02 11/23/1965 14 3.29 3.32
0.02 12/9/1965 13 3.54 3.59
0.02 12/9/1965 12 3.83 3.90
0.02 12/9/1965 11 4.18 4.26
0.02 12/9/1965 10 4.60 4.71
0.02 12/9/1965 9 5.11 5.26
0.02 12/9/1965 8 5.75 5.95
0.02 12/9/1965 7 6.57 6.85
0.02 12/9/1965 6 7.67 8.07
0.118 1/6/1979 5 9.20 9.83
0.415 12/5/1966 4 11.50 12.56
1.164 12/18/1978 3 15.33 17.38
1.185 1/15/1978 2 23.00 28.25
1.92 11/23/1965 1 46.00 75.33
Peaks (cfs)
Period of Return
(Years)
ATTACHMENT 4
AREA VS ELEVATION
The storage provided by the detention vault is entered into the Storage Module within SWMM – please refer to Attachment 7 for further information. It should be noted that all facilities are walled; as such the stage‐area relationship is a constant. A stage‐storage calculation is provided on the following page for verification.
DISCHARGE VS ELEVATION
Due to elevation constraints on the project site, the outlets from the vault are pumps – as such a constant flow out from the vault is experienced when the volume within the basin exceeds the invert elevation of the pump outlet invert.
Stage‐Storage‐Discharge Summary Table
Depth (ft) Area (ft2) Volume (ft3) Ac‐Ft Q‐out (cfs)
0 360 0 0 0
1 360 360 0.008264 0
2 360 720 0.016529 0
3 360 1080 0.024793 0
3.2 360 1152 0.026446 0.02
4 360 1440 0.033058 0.02
5 360 1800 0.041322 0.02
6 360 2160 0.049587 0.02
7 360 2520 0.057851 0.02
7.25 360 2610 0.059917 1.902
8 360 2880 0.066116 1.902
9 360 3240 0.07438 1.902
ATTACHMENT 5
Pre & Post‐Developed Maps, Project Plan and Detention
Section Sketches
1 DMA/BMP PLAN - PROPOSED
PICO PLACE
236-244 SAN MARCOS PICO AVENUE
SAN MARCOS, CA 92069
ATTACHMENT 6
SWMM Input Data in Input Format (Existing & Proposed Models)
PRE_DEV
[TITLE]
[OPTIONS]
FLOW_UNITS CFS
INFILTRATION GREEN_AMPT
FLOW_ROUTING KINWAVE
START_DATE 10/05/1962
START_TIME 00:00:00
REPORT_START_DATE 10/05/1962
REPORT_START_TIME 00:00:00
END_DATE 10/05/2007
END_TIME 23:00:00
SWEEP_START 01/01
SWEEP_END 12/31
DRY_DAYS 0
REPORT_STEP 01:00:00
WET_STEP 00:15:00
DRY_STEP 04:00:00
ROUTING_STEP 0:01:00
ALLOW_PONDING NO
INERTIAL_DAMPING PARTIAL
VARIABLE_STEP 0.75
LENGTHENING_STEP 0
MIN_SURFAREA 0
NORMAL_FLOW_LIMITED BOTH
SKIP_STEADY_STATE NO
FORCE_MAIN_EQUATION H-W
LINK_OFFSETS DEPTH
MIN_SLOPE 0
[EVAPORATION]
;;Type Parameters
;;---------- ----------
MONTHLY 0.07 0.1 0.13 0.17 0.19 0.22 0.24 0.22 0.19 0.13 0.09 0.06 DRY_ONLY NO
[RAINGAGES]
;; Rain Time Snow Data
;;Name Type Intrvl Catch Source
;;-------------- --------- ------ ------ ----------
Poway INTENSITY 1:00 1.0 TIMESERIES Poway
[SUBCATCHMENTS]
;; Total Pcnt. Pcnt. Curb Snow
;;Name Raingage Outlet Area Imperv Width Slope Length Pack ;;-------------- ---------------- ---------------- -------- -------- -------- -------- -------- -------- DMA-1-C Poway POC-1 0.675 0 114 1 0
[SUBAREAS]
;;Subcatchment N-Imperv N-Perv S-Imperv S-Perv PctZero RouteTo PctRouted ;;-------------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- DMA-1-C 0.012 0.05 0.05 0.1 25 OUTLET
[INFILTRATION]
;;Subcatchment Suction HydCon IMDmax
;;-------------- ---------- ---------- ----------
DMA-1-C 6 0.075 0.32
[OUTFALLS]
;; Invert Outfall Stage/Table Tide
;;Name Elev. Type Time Series Gate
;;-------------- ---------- ---------- ---------------- ---- POC-1 0 FREE NO
[TIMESERIES]
;;Name Date Time Value
;;-------------- ---------- ---------- ----------
Poway FILE "PowayRain.prn"
[REPORT]
INPUT NO
PRE_DEV
CONTROLS NO
SUBCATCHMENTS ALL
NODES ALL
LINKS ALL
[TAGS]
[MAP]
DIMENSIONS -2332.031 5700.000 3253.906 12300.000
Units None
[COORDINATES]
;;Node X-Coord Y-Coord
;;-------------- ------------------ ------------------
POC-1 -1889.283 9043.612
[VERTICES]
;;Link X-Coord Y-Coord
;;-------------- ------------------ ------------------
[Polygons]
;;Subcatchment X-Coord Y-Coord
;;-------------- ------------------ ------------------
DMA-1-C -2819.679 11253.304
[SYMBOLS]
;;Gage X-Coord Y-Coord
;;-------------- ------------------ ------------------
Poway 3324.814 11388.987
POST_DEV
[TITLE]
[OPTIONS]
FLOW_UNITS CFS
INFILTRATION GREEN_AMPT
FLOW_ROUTING KINWAVE
START_DATE 10/05/1962
START_TIME 00:00:00
REPORT_START_DATE 10/05/1962
REPORT_START_TIME 00:00:00
END_DATE 10/05/2007
END_TIME 23:00:00
SWEEP_START 01/01
SWEEP_END 12/31
DRY_DAYS 0
REPORT_STEP 01:00:00
WET_STEP 00:15:00
DRY_STEP 04:00:00
ROUTING_STEP 0:01:00
ALLOW_PONDING NO
INERTIAL_DAMPING PARTIAL
VARIABLE_STEP 0.75
LENGTHENING_STEP 0
MIN_SURFAREA 0
NORMAL_FLOW_LIMITED BOTH
SKIP_STEADY_STATE NO
FORCE_MAIN_EQUATION H-W
LINK_OFFSETS DEPTH
MIN_SLOPE 0
[EVAPORATION]
;;Type Parameters
;;---------- ----------
MONTHLY 0.07 0.1 0.13 0.17 0.19 0.22 0.24 0.22 0.19 0.13 0.09 0.06 DRY_ONLY NO
[RAINGAGES]
;; Rain Time Snow Data
;;Name Type Intrvl Catch Source
;;-------------- --------- ------ ------ ----------
Poway INTENSITY 1:00 1.0 TIMESERIES Poway
[SUBCATCHMENTS]
;; Total Pcnt. Pcnt. Curb Snow
;;Name Raingage Outlet Area Imperv Width Slope Length Pack ;;-------------- ---------------- ---------------- -------- -------- -------- -------- -------- -------- DMA-1-C Poway 1 0.675 74.79 114 1 0
[SUBAREAS]
;;Subcatchment N-Imperv N-Perv S-Imperv S-Perv PctZero RouteTo PctRouted ;;-------------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- DMA-1-C 0.012 0.05 0.05 0.1 25 OUTLET
[INFILTRATION]
;;Subcatchment Suction HydCon IMDmax
;;-------------- ---------- ---------- ----------
DMA-1-C 6 0.075 0.32
[OUTFALLS]
;; Invert Outfall Stage/Table Tide
;;Name Elev. Type Time Series Gate
;;-------------- ---------- ---------- ---------------- ---- POC-1 0 FREE NO
[STORAGE]
;; Invert Max. Init. Storage Curve Ponded Evap.
;;Name Elev. Depth Depth Curve Params Area Frac. Infiltration Parameters
;;-------------- -------- -------- -------- ---------- -------- -------- -------- -------- -------- ----------------- ------
1 0 9 0 TABULAR Vault 360 0 6 1.5
0.32 POST_DEV
[OUTLETS]
;; Inlet Outlet Outflow Outlet Qcoeff/ Flap
;;Name Node Node Height Type QTable Qexpon Gate
;;-------------- ---------------- ---------------- ---------- --------------- ---------------- ---------- ---- 1 1 POC-1 0 TABULAR/DEPTH Out NO
[CURVES]
;;Name Type X-Value Y-Value
;;-------------- ---------- ---------- ----------
Out Rating 0 0
Out 0.49 0
Out 0.5 0
Out 1 0
Out 2 0
Out 3 0
Out 3.19 0.0001
Out 3.2 0.02
Out 4 0.02
Out 5 0.02
Out 6 0.02
Out 7 0.02
Out 7.24 0.02
Out 7.25 1.920
Out 8 1.922
Out 9 1.923
Vault Storage 0 360
Vault 9 360
[TIMESERIES]
;;Name Date Time Value
;;-------------- ---------- ---------- ----------
Poway FILE "PowayRain.prn"
[REPORT]
INPUT NO
CONTROLS NO
SUBCATCHMENTS ALL
NODES ALL
LINKS ALL
[TAGS]
[MAP]
DIMENSIONS -2332.031 5700.000 3253.906 12300.000
Units None
[COORDINATES]
;;Node X-Coord Y-Coord
;;-------------- ------------------ ------------------
POC-1 -1889.283 9043.612
1 -2383.226 10232.685
[VERTICES]
;;Link X-Coord Y-Coord
;;-------------- ------------------ ------------------
[Polygons]
;;Subcatchment X-Coord Y-Coord
;;-------------- ------------------ ------------------
DMA-1-C -2819.679 11253.304
[SYMBOLS]
;;Gage X-Coord Y-Coord
;;-------------- ------------------ ------------------
Poway 22.077 10601.554
ATTACHMENT 7
EPA SWMM FIGURES AND EXPLANATIONS
Per the attached, the reader can see the screens associated with the EPA‐SWMM Model in both pre‐development and post‐development conditions. Each portion, i.e., sub‐catchments, outfalls, storage units, weir as a discharge, and outfalls (point of compliance), are also shown.
Variables for modeling are associated with typical recommended values by the EPA‐SWMM model, typical values found in technical literature (such as Maidment’s Handbook of Hydrology). Recommended values for the SWMM model have been attained from Appendix G of the 2016 City of San Marcos BMP Design Manual.
Soil characteristics of the existing soils were determined from the NRCS Web Soil Survey and site specific geotechnical report (located in Attachment 8 of this report).
A Technical document prepared by Tory R Walker Engineering for the Cities of San Marcos, Oceanside and Vista (Reference [1]) can also be consulted for additional information regarding typical values for SWMM parameters.
Manning’s roughness coefficients have been based upon the findings of the “Improving Accuracy in Continuous Hydrologic Modeling: Guidance for Selecting Pervious Overland Flow Manning’s n Values in the San Diego Region” date 2016 by TRW Engineering (Reference [6]).
PRE‐DEVELOPED CONDITION
POST‐DEVELOPED CONDITION
Detention Basin
EXPLANATION OF SELECTED VARIABLES
Sub Catchment Areas:
Please refer to the attached diagrams that indicate the DMA and detention BMPs (BMP) sub areas modeled within the project site at both the pre and post developed conditions draining to the POC.
Parameters for the pre‐ and post‐developed models include soil type C as determined from the NRCS websoil survey review (attached at the end of this appendix). Suction head, conductivity and initial deficit corresponds to average values expected for these soils types, according to Appendix G of the 2016 City of San Marcos BMP Design Manual.
For surface runoff infiltration values, REC selected infiltration values per Appendix G of the 2016 City of San Marcos BMP Design Manual corresponding to hydrologic soil type.
Selection of a Kinematic Approach: As the continuous model is based on hourly rainfall, and the time of concentration for the pre‐development and post‐development conditions is significantly smaller than 60 minutes, precise routing of the flows through the impervious surfaces, the underdrain pipe system, and the discharge pipe was considered unnecessary. The truncation error of the precipitation into hourly steps is much more significant than the precise routing in a system where the time of concentration is much smaller than 1 hour.
Overland Flow Manning’s Coefficient per TRWE (Reference [6]) 3 Further discussion is provided on page 6 under “Discussion of Differences Between Manning’s n Values” 3 appeal of a de facto value, we anticipate that jurisdictions will not be inclined to approve land surfaces other than short prairie grass. Therefore, in order to provide SWMM users with a wider range of land surfaces suitable for local application and to provide Copermittees with confidence in the design parameters, we recommend using the values published by Yen and Chow in Table 3-5 of the EPA SWMM Reference Manual Volume I – Hydrology.
SWMM-Endorsed Values Will Improve Model Quality
In January 2016, the EPA released the SWMM Reference Manual Volume I – Hydrology (SWMM Hydrology Reference Manual). The SWMM Hydrology Reference Manual complements the SWMM 5 User’s Manual and SWMM 5 Applications Manual by providing an in-depth description of the program’s hydrologic components (EPA 2016). Table 3-5 of the SWMM Hydrology Reference Manual expounds upon SWMM 5 User’s Manual Table A.6 by providing Manning’s n values for additional overland flow surfaces3
. The values are provided in Table 1:
Table 1: Manning’s n Values for Overland Flow (EPA, 2016; Yen 2001; Yen and Chow, 1983).
Overland Surface Light Rain
(< 0.8 in/hr)
Moderate Rain
(0.8-1.2 in/hr)
Heavy Rain
(> 1.2 in/hr)
Smooth asphalt pavement 0.010 0.012 0.015
Smooth impervious surface 0.011 0.013 0.015
Tar and sand pavement 0.012 0.014 0.016
Concrete pavement 0.014 0.017 0.020
Rough impervious surface 0.015 0.019 0.023
Smooth bare packed soil 0.017 0.021 0.025
Moderate bare packed soil 0.025 0.030 0.035
Rough bare packed soil 0.032 0.038 0.045
Gravel soil 0.025 0.032 0.045
Mowed poor grass 0.030 0.038 0.045
Average grass, closely clipped sod 0.040 0.050 0.060
Pasture 0.040 0.055 0.070
Timberland 0.060 0.090 0.120
Dense grass 0.060 0.090 0.120
Shrubs and bushes 0.080 0.120 0.180
Land Use
Business 0.014 0.022 0.035
Semibusiness 0.022 0.035 0.050
Industrial 0.020 0.035 0.050
Dense residential 0.025 0.040 0.060
Suburban residential 0.030 0.055 0.080
Parks and lawns 0.040 0.075 0.120
For purposes of local hydromodification management BMP design, these Manning’s n values are an improvement upon the values presented by Engman (1986) in SWMM 5 User’s Manual Table A.6. Values from SWMM 5 User’s Manual Table A.6, while completely suitable for the intended application to certain agricultural land covers, comes with the disclaimer that the provided Manning’s n values are valid for shallow-depth overland flow that match the conditions in the experimental plots (Engman, ATTACHMENT 8
Geotechnical Documentation
3 Corporate Park, Suite 270, Irvine, California 92606
Office (949) 221-0900 Fax (949) 221-0091
Email: [email protected]
August 31, 2022
Project 9421-04
DMS Consultants, Inc.
12377 Lewis Street, Suite 203
Garden Grove, California 92840
Attention: Mr. Surender Dewan, P. E.
President
Subject: Geotechnical Investigation
Proposed Multi-Family Residential Development
236 and 244 Pico Avenue
San Marcos, California
References: See Appendix A
Dear Mr. Dewan:
1. INTRODUCTION
a) In accordance with your request, we have conducted a geotechnical investigation for the proposed residential development located in San Marcos, California. b) We understand that the proposed development will consist of the construction of four 3-story, multi-family residential structures, each unit approximately 1,170- squarefoot, with related parking/driveway areas on a 0.67-acre parcel of land. In addition, an infiltration system is planned to be installed for potential stormwater runoff.
c) Grading and structural plans are not available at present. We are assuming that the existing grades will remain unchanged. We anticipate the loads from the proposed structures will not exceed 3 kip/ft for the continuous footings and 50 kips for the column footings.
2. SCOPE
The scope of services we provided were as follows:
a) Preliminary planning and evaluations, and review of geotechnical reports related to the project site and nearby surrounding area (See References – Appendix A); GLOBAL GEO-ENGINEERING, INC.
DMS Consultants, Inc.
August 31, 2022
Project 9421-04
b) Excavation of three (3) borings utilizing a hollow stem auger drill rig to a maximum depth of 40 feet below ground surface. One of the borings was drilled to a depth of 5 feet below ground surface for the purpose of percolation testing; c) Sampling and logging of subsurface materials encountered in the borings; d) Field percolation testing to determine the infiltrations rate; e) Laboratory testing of samples representative of those obtained in the field, in order to evaluate relevant engineering properties;
f) Engineering and geologic analyses of the field and laboratory data; g) Preparation of a report presenting our findings, conclusions and recommendations.
3. FIELD EXPLORATION AND LABORATORY TESTING
The field exploration program is given in Appendix B, which includes the Logs of Borings.
The results of the laboratory testing are included in Appendix C.
4. SITE DESCRIPTION
4.1 Location
a) The project site is located along the southwest side of Pico Avenue, approximately 280 feet northwest of San Marcos Boulevard, in the city of San Marcos, California.
b) The approximate site location is shown on the Location Map, Figure 1.
4.2 Existing Surface Conditions
a) The subject property is currently vacant and void of any building structures. b) The ground surface throughout the project site is relatively level. The natural topography of the site area descends to the south at an approximate gradient of one percent.
c) Surface drainage consists of sheet flow runoff of incident rainfall water derived primarily within the property boundaries and adjacent properties.
LOCATION MAP
244 Pico Avenue
San Marcos, California
Date: August 2022
Project No.: 9421-04
Figure No:
GLOBAL GEO-ENGINEERING, INC.
GEOLOGIC AND SOILS ENGINEERING IRVINE, CALIFORNIA
1 2000 0 2000 4000
SCALE FEET
BASE MAP: USGS 7.5-Minute Topographic Map,
San Marcos Quadrangle, 1999 N
O
R
T
H
SITE
DMS Consultants, Inc.
August 31, 2022
Project 9421-04
4.3 Geology
4.3.1 Regional Geologic Setting
The subject property is located within the Peninsular Ranges Geomorphic Province of California. The Peninsular Ranges consist of a series of mountain ranges separated by longitudinal valleys. The ranges trend northwest-southeast and are sub parallel to faults branching from the San Andreas Fault. The Peninsular Ranges extend from the southern side of the Santa Monica and San Gabriel Mountains into Baja California, Mexico (CDMG, 1997).
4.3.2 Local Geologic Setting
In general, the project site area is underlain by Recent- to Older-aged alluvial deposits which overlie granitic bedrock.
4.4 Subsurface Conditions
a) The subsurface conditions, as encountered in our explorations, are described in the following sections.
b) More detailed descriptions of the subsurface conditions are presented in our Logs of Borings, which are enclosed as Figures B-2 through B-4 in Appendix B. The locations of the borings are shown on our Boring Location Plan, Figure B-5.
4.4.1 Alluvium
a) Alluvial deposits were encountered in all of our borings excavated on-site.
b) The alluvium was found to generally consist of interlayers of Silty SAND, SAND and Sandy to Clayey SILT.
c) The Silty SAND and SAND sediments were generally found to be fine to coarse grained, slightly moist to very moist and medium dense.
d) The Sandy to Clayey SILT deposits were observed to be slightly moist to moist and stiff.
DMS Consultants, Inc.
August 31, 2022
Project 9421-04
4.4.2 Bedrock
a) Bedrock, classified as Tonalite, was encountered at a depth of 37 feet below ground surface in Boring B-1.
b) The bedrock encountered in our boring was noted to be fine textured and hard.
4.4.3 Groundwater
a) Groundwater was encountered in our deeper boring (Boring B-1) at a depth of 24 feet below ground surface. The static water level was measured at a depth of 23.5 feet below ground surface approximately 30 minutes after termination of drilling.
b) No nearby groundwater wells were found to be listed during our review of the California Department of Water Resources internet website.
5. SEISMICITY
5.1 General
a) The property is located in the general proximity of several active and potentially active faults, which are typical for sites in the Southern California region. Earthquakes occurring on active faults within a 70-mile radius are capable of generating ground shaking of engineering significance to the proposed construction.
b) In Southern California, most of the seismic damage to manmade structures results from ground shaking and, to a lesser degree, from liquefaction and ground rupture caused by earthquakes along active fault zones. In general, the greater the magnitude of the earthquake, greater is the potential damage.
5.2 Ground Surface Rupture
a) The closest known active fault is the Elsinore Fault, located at a distance of about 16.3 miles northeast of the project site. Other nearby active or potentially active faults include the Rose Canyon Fault and the San Jacinto Fault located at distances of about 20.8 miles and 40.8 miles, respectively, from the subject property.
b) Due to the distance of the closest active fault to the site, ground rupture is not considered a significant hazard at the site.
DMS Consultants, Inc.
August 31, 2022
Project 9421-04
5.3 Ground Shaking
a) We utilized the California Office of Statewide Health Planning and Development (OSHPD) Seismic Design Maps internet program to calculate the peak ground acceleration (PGA) at the project site location.
Using the ASCE 7-16 standard and Site Class D, the PGA at the subject property resulted to be 0.47g.
b) Figure 2 shows the geographical relationships among the site locations, nearby faults and the epicenters of significant occurrences. The project site is not located within any State of California delineated Earthquake Fault Zone; however, during historic times, a number of major earthquakes have occurred along the active faults in Southern California. From the seismic history of the region and proximity, the Elsinore Fault and Rose Canyon Fault have the greatest potential for causing earthquake damage related to ground shaking at this site.
5.4 Liquefaction
The subject site is underlain by dense soil layers overlying a Tonalite bedrock.
The potential for the liquefaction is considered to be low.
6. CONCLUSIONS AND RECOMMENDATIONS
6.1 General
a) It is our opinion that the site will be suitable for the proposed development, from a geotechnical aspect, assuming that our recommendations are implemented.
b) We are of the opinion that the proposed structures can be supported on shallow spread footings founded in the existing competent soils. c) We consider that the anticipated grading will not adversely affect, nor be adversely affected by adjoining property, with due precautions being taken.
d) The final grading plans and foundation plans/design loads should be reviewed by the Geotechnical Engineer.
e) The design recommendations in the report should be reviewed during the construction phase.
244 Pico Avenue
San Marcos, California
Date: August 2022
Project No: 9421-04
Figure No:
2 GLOBAL GEO-ENGINEERING, INC.
GEOLOGIC AND SOILS ENGINEERING
IRVINE, CALIFORNIA
MAJOR EARTHQUAKES AND RECENTLY ACTIVE FAULTS IN THE
SOUTHERN CALIFORNIA REGION
EXPLANATION
EARTHQUAKE LOCATIONS
Approximate epicentral area of earthquakes that
occurred 1769-1933. magnitudes not recorded by
instruments prior to 1906 were estimated from
damage reports assigned on Intensity VII (Modified
Mercali scale) or greater; this is roughly equivalent
to Richter M 6.0. 31 moderate**earthquakes, 7 major
and one great earthquake (1857) were reported in the
164-year period 1769-1933.
Earthquake epicenters since 1933, plotted from
instruments. 33 moderate** and five major
earthquakes were in the 66-year period 1933 to 1999.
ACTIVE FAULTS
Total length of fault zone that breaks
Halocene deposits or that has had
seismic activity.
Fault segment with surface rupture
during an historic earthquake, or with
aseismic fault creep.
Halocene volcanic activity
(Amboy, Pisgah, Cerro Prieto and Salton
Buttes
1899
M7+
1952
M7.7
**Code recommendations by the Structural Engineers Association of California define a great earthquake as one that has a Richter Magnitude of 7 ¾ or greater; a major earthquake 7 to 7 ¾; a moderate earthquake 6 to 7.
Compiled by Richard J. Proctor mainly from published and unpublished data of the California Division of Mines and Geology; California Department of Water Resources Bulletin 116-2 (1964); selections from bulletins of the Geological and Seismological Societies of America; from C.F. Richter, Elementary Seismology (1958); and the National Atlas, p. 66, and from Working Group on California Earthquake Probabilities- SSA Bulletin V 85.
SITE
DMS Consultants, Inc.
August 31, 2022
Project 9421-04
6.2 Grading
6.2.1 Processing of On-Site Soils
a) To provide uniform support conditions, the subgrade soils should be overexcavated to a depth of one foot below the foundation bottom and three feet below the slab-on-grade, subject to review during construction. The overexcavation should laterally extend for a distance of 5 feet.
b) There should be at least one foot of reworked soils or compacted fill below the pavements.
c) Wherever structural fills are to be placed, the upper 6 to 8 inches of the subgrade should, after stripping or overexcavation, first be scarified, reworked and wetted down thoroughly.
d) Any loosening of reworked or native material, consequent to the passage of construction traffic, weathering, etc., should be made good prior to further construction.
e) The depths of overexcavation should be reviewed by the Geotechnical Engineer during the actual construction. Any surface or subsurface obstructions, or questionable material encountered during grading should be brought immediately to the attention of the Geotechnical Engineer for proper exposure, removal or processing as directed. No underground obstructions or facilities should remain in any structural areas. Depressions and/or cavities created as a result of the removal of obstructions should be backfilled properly with suitable material, and compacted.
6.2.2 Material Selection
After the site has been stripped of any debris, vegetation and organic soils, excavated on-site soils are considered satisfactory for reuse in the construction of on-site fills, with the following provisions:
a) Significant water will be required to be added to the existing soils; b) The organic content does not exceed 3 percent by volume; c) Large size rocks greater than 8 inches in diameter should not be incorporated in compacted fill;
DMS Consultants, Inc.
August 31, 2022
Project 9421-04
d) Rocks greater than 4 inches in diameter should not be incorporated in compacted fill to within one foot of the underside of the footings and slabs.
6.2.3 Compaction Requirements
a) Reworking/compaction shall include moisture-conditioning as needed to bring the soils to slightly above the optimum moisture content. All reworked soils and structural fills should be densified to achieve at least 90 percent relative compaction with reference to laboratory compaction standard. The optimum moisture content and maximum dry density should be determined in the laboratory in accordance with ASTM Test Designation D1557.
b) Fill should be compacted in lifts not exceeding 8 inches (loose).
6.2.4 Excavating Conditions
a) Excavation of on-site materials may be accomplished with standard earthmoving or trenching equipment. No hard rock was encountered which will require blasting.
b) Ground water was encountered at a depth of 24 feet below ground surface in our deeper boring. Dewatering is not anticipated in excavations shallower than 24 feet below ground surface.
6.2.5 Shrinkage
For preliminary earthwork calculation, an average shrinkage factor of approximately 5 percent is recommended for the soils (this does not include handling losses).
6.2.6 Expansion Potential
a) Based upon our visual observations, the expansion potential for the on-site soils is considered to be medium. The recommendations provided in the following sections will reduce the effects of the expansive subgrade soils.
b) Any imported material, or doubtful material exposed during grading, should be evaluated for its expansive properties. c) In any event, the subgrade soils should be tested for their expansion potential or during the final stages of grading.
DMS Consultants, Inc.
August 31, 2022
Project 9421-04
6.2.7 Sulphate Content
a) The sulphate contents of representative samples of the soil are less than 0.1%. The sulphate exposure is considered to be negligible.
Type II Portland cement is recommended for the construction. a) The fill materials should be tested for their sulphate content during the final stage of rough grading.
6.2.8 Utility Trenching
a) The walls of temporary construction trenches in fill should stand nearly vertical, with only minor sloughing, provided the total depth does not exceed 3 feet (approximately). Shoring of excavation walls or flattening of slopes may be required, if greater depths are necessary.
b) Trenches should be located so as not to impair the bearing capacity or to cause settlement under foundations. As a guide, trenches should be clear of a 45-degree plane, extending outward and downward from the edge of foundations. Shoring should comply with Cal-OSHA regulations.
c) Existing soils may be utilized for trenching backfill, provided they are free of organic materials.
d) All work associated with trench shoring must conform to the state and federal safety codes.
6.2.9 Surface Drainage Provisions
Positive surface gradients should be provided adjacent to the buildings to direct surface water run-off away from structural foundations and to suitable discharge facilities.
6.2.10 Grading Control
All grading and earthwork should be performed under the observation of a Geotechnical Engineer in order to achieve proper subgrade preparation, selection of satisfactory materials, placement and compaction of all structural fill. Sufficient notification prior to stripping and earthwork construction is essential to make certain that the work will be adequately observed and tested.
DMS Consultants, Inc.
August 31, 2022
Project 9421-04
6.3 Slab-on-Grade
a) Concrete floor slabs may be founded on the reworked existing soils or compacted fill.
b) The slab should be underlain by four inches of granular material. A plastic vapor barrier is recommended to be placed at the mid-height of the base layer.
c) It is recommended that #4 bars on 12-inch center, both ways, or equivalent be provided as minimum reinforcement in slabs-on-grade. Joints should be provided and slabs supporting no vehicular traffic should be at least 5 inches thick.
d) The FFL should be at least 6 inches above highest adjacent grade. e) The subgrade soils should be kept moist prior to the concrete pour.
6.4 Spread Foundations
The proposed structures can be founded on shallow spread footings. The criteria presented as follows should be adopted:
6.4.1 Dimensions/Embedment Depths
Number of Stories
(floors supported)
Minimum Width
(ft.)
Minimum Footing
Thickness
(in.)
Minimum Embedment
Below Lowest Finished Surface
(ft.)
3 1.5 6 Perimeter 2.5
Interior 2.5
Square Column
Footings
To 50 kip
2 - 2.5
6.4.2 Allowable Bearing Capacity
Embedment Depth
(ft.)
Allowable Bearing Capacity
(lb/ft2)
1.0 2,000
(Notes:
• The allowable bearing capacity may be increased by 800 lb/ft2 for each additional foot increase in the depth or by 200 lb/ft2 he width to a maximum value of 4,000 lb/ft2
;
DMS Consultants, Inc.
August 31, 2022
Project 9421-04
• These values may be increased by one-third in the case of shortduration loads, such as induced by wind or seismic forces; • At least 2x#4 bars should be provided in wall footings, one on top and one at the bottom;
• In the event that footings are founded in structural fills consisting of imported materials, the allowable bearing capacities will depend on the type of these materials, and should be re-evaluated;
• Bearing capacities should be re-evaluated when loads have been obtained and footings sized during the preliminary design; • Planter areas should not be sited adjacent to walls;
• Footing excavations should be observed by the Geotechnical Engineer; • Footing excavations should be kept moist prior to the concrete pour; • It should be insured that the embedment depths do not become reduced or adversely affected by erosion, softening, planting, digging, etc.)
6.4.3 Settlements
Total and differential settlements under spread footings are expected to be within tolerable limits and are not expected to exceed 1 and ¾ inches in a horizontal distance of 40 feet, respectively.
6.5 Lateral Pressures
a) The following lateral pressures are recommended for the design of retaining structures.
Pressure (lb/ft2/ft depth)
Lateral Force Soil Profile Unrestrained Wall Rigidly Supported Wall Active Pressure Level 36 -
At-Rest Pressure Level - 65
Passive Resistance
(ignore upper 1.5 ft.) Level 300 -
DMS Consultants, Inc.
August 31, 2022
Project 9421-04
b) Friction coefficient: 0.35 (includes a Factor of Safety of 1.5). While combining friction with passive resistance, reduce passive by 1/3. c) These values apply to the existing soil, and to compacted backfill generated from in-situ material. Imported material should be evaluated separately. It is recommended that where feasible, imported granular backfill be utilized, for a width equal to approximately one-quarter the wall height, and not less than 1.5 feet.
d) Backfill should be placed under engineering control. e) Subdrains comprised of 4-inch perforated SDR-35 or equivalent PVC pipe covered in a minimum of one cubic foot per linear foot of filter rock and wrapped in Mirafi 140N filter fabric should be provided behind retaining walls.
6.6 Seismic Coefficients and Liquefaction Potential
a) For seismic analysis of the proposed project in accordance with the seismic provisions of ASCE 7-16, we recommend the following:
ITEM VALUE
Site Latitude (Decimal-degrees) 33.14197
Site Longitude (Decimal-degrees) -117.16598
Site Class D
Risk Category II
Mapped Spectral Response Acceleration-Short Period (0.2 Sec) - SS 0.897 Mapped Spectral Response Acceleration-1 Second Period – S1 0.33 Short Period Site Coefficient-Fa 1.141
Long Period Site Coefficient Fv 1.90
Adjusted Spectral Response Acceleration @ 0.2 Sec. Period (Sms) 1.024 Adjusted Spectral Response Acceleration @ 1Sec.Period (Sm1) 0.627 Design Spectral Response Acceleration @ 0.2 Sec. Period (SDs) 0.682 Design Spectral Response Acceleration @ 1-Sec. Period (SD1) 0.418 b) Ground water was encountered at a depth of 24 feet below ground surface, however, the subject site is underlain by dense soil layers. The potential for liquefaction is considered to be low.
DMS Consultants, Inc.
August 31, 2022
Project 9421-04
6.7 Pavement Design
6.7.1 Asphalt Pavement Section
a) Based on Traffic Indices (T.I) and on the anticipated “R” – Value of 42 of the subgrade, the following tentative structural pavement sections are recommended.
b) The subgrade soils should be tested for R-Value at the conclusion of rough grading and the pavement sections should be finalized then.
6.7.2 Subgrade Preparation
Subgrade soils within the upper 12 inches of finished grade shall be moisture-conditioned where necessary, shall be compacted to at least 90 percent relative compaction per ASTM D1557, and shall be free of any loose or soft areas.
6.7.3 Base Preparation
Unless otherwise specified, the base shall consist of Class II ¾-inch aggregate base or approved Crushed Miscellaneous Base. The base shall be compacted to a minimum of 95 percent relative compaction in accordance with the procedures described in ASTM Test Method D1557.
6.7.4 Concrete Pavement
If proposed, the concrete pavement should be at least 5 inches thick, reinforced with #4 bars on 12 inches center bothways, underlain by 4 inches thick base as recommended above. Thicker concrete section will be required for traffic greater than T.I. of 6.0.
6.8 Corrosion Potential
a) Soil Corrosion potential for metal and concrete was estimated by performing water-soluble sulfate, chloride, pH, and electrical resistivity tests during this investigation.
Location T.I. Asphaltic Concrete
(inches)
Aggregate Base
(inches)
Parking and Driveways Up to 5.0 3 4
Driveway
(light truck traffic) 6.0 3 6
DMS Consultants, Inc.
August 31, 2022
Project 9421-04
b) Electrical resistivity is a measure of soil resistance to the flow of corrosion currents. Corrosion currents are generally high in low resistivity soils.
The electrical resistivity of a soil decreases primarily with an increase in its chemical and moisture contents.
c) A commonly accepted correlation between electrical resistivity and corrosivity for buried ferrous metals is presented below:
Electrical Resistivity, Ohm-cm Corrosion Potential
Less than 1,000 Severe
1,000-2,000 Corrosive
2,000-10,000 Moderate
Greater than 10,000 Mild
d) Results of electrical resistivity test indicate a value of 3,339 ohm-cm for the near-surface soils. Based on this data, it is our opinion that, in general, on-site near-surface soils are considered moderately corrosive in nature.
This potential should be considered in design of underground metal pipes.
6.9 Percolation Study
a) The soils in the upper 5 feet were Clayey Silty SAND underlain by Silty SAND/Sandy SILT. We recommend the basin to be at least 6 feet deep. b) As more granular soils are anticipated at that depth, we estimate the following infiltration rate. During the grading operation, a percolation test should be conducted to verify the infiltration rate.
Boring No. Percolation Rate (inch/hour)
P-1 3.0
c) These rates are calculated using a factor of safety of 1.0. Appropriate factor of safety should be utilized while designing the basin.
DMS Consultants, Inc.
August 31, 2022
Project 9421-04
7. LIMITATIONS
a) Soils and bedrock over an area show variations in geological structure, type, strength and other properties from what can be observed, sampled and tested from specimens extracted from necessarily limited exploratory borings. Therefore, there are natural limitations inherent in making geologic and soil engineering studies and analyses.
Our findings, interpretations, analyses and recommendations are based on observation, laboratory data and our professional experience; and the projections we make are professional judgments conforming to the usual standards of the profession. No other warranty is herein expressed or implied. b) In the event that during construction, conditions are exposed which are significantly different from those described in this report, they should be brought to the attention of the Geotechnical Engineer.
The opportunity to be of service is sincerely appreciated. If you have any questions or if we can be of further assistance, please call.
Very truly yours,
GLOBAL GEO-ENGINEERING, INC.
Mohan B. Upasani Kevin B. Young
Principal Geotechnical Engineer Principal Engineering Geologist RGE 2301 CEG 2253
(Exp. March 31, 2023) (Exp. October 31, 2023)
MBU/KBY: fdg
Enclosures:
Location Map
Seismicity Map
References
Field Exploration
Unified Soils Classification System
Logs of Borings
- Figure 1
- Figure 2
- Appendix A
- Appendix B
Figure B-1
Figures B-2 through B-3
Boring Location Plan Figure B-4
Laboratory Testing - Appendix C
Project 9421-04
APPENDIX A
References
1. California Geological Survey, Earthquake Fault Zones of Required Investigation, (Internet).
2. California Division of Mines and Geology, 1996, Geologic Maps of the Northwestern Part of San Diego County, California, CDMG Open File Report 96-02.
3. California Office of Statewide Health Planning and Development, Seismic Design Maps Web Tool, ASCE 7-16 Standard (Internet).
4. United States Geological Survey, 1948, San Marcos Quadrangle, 7.5-Minute Topographic Series.
5. United States Geological Survey, 1968, San Marcos Quadrangle, 7.5-Minute Topographic Series.
6. United States Geological Survey, 1968 photorevised 1983, San Marcos Quadrangle, 7.5- Minute Topographic Series.
Project 9421-04
APPENDIX B
Field Exploration
a) The site was explored on May 17, 2022, utilizing a B-61 Mobile hollow stem drill rig to excavate three borings to a maximum depth of 40 feet below the existing ground surface.
One of the borings were subsequently backfilled. Three-inch diameter perforated pipe with gravel rock encasement was installed in Boring P-1 for the purpose of percolation testing b) The soils encountered in the excavations were logged and sampled by our Engineering Geologist. The soils were classified in accordance with the Unified Soil Classification System described in Figure B-1. The Logs of Borings are presented in Figures B-2 through B-4. The approximate locations of the borings are shown on the Boring Location Plan, Plate
1. The logs, as presented, are based on the field logs, modified as required from the results of the laboratory tests. Driven ring and bulk samples were obtained from the excavations for laboratory inspection and testing. The depths at which the samples were obtained are indicated on the logs.
c) The number of blows of the driving weight during sampling was recorded, together with the depth of penetration, the driving weight and the height of fall. The blows required per foot of penetration for given samples was then calculated and shown on the logs. d) Groundwater was encountered at a depth of 24 feet below ground surface in Boring B-1. e) Caving occurred in all of the borings to the depths noted on the logs.
UNIFIED SOILS CLASSIFICATION (ASTM D-2487)
PRIMARY DIVISION GROUP SYMBOL SECONDARY DIVISIONS
COARSE GRAINED SOILS
More than half of materials is
larger than #200 sieve size
GRAVELS
More than half
of coarse
fraction is larger
than #4 sieve
Clean
Gravels
(<5% fines)
GW Well graded gravels, gravel-sand mixture, little or no fines GP Poorly graded gravels or gravel-sand mixtures, little or no fines Gravel with
Fines
GM Silty gravels, gravel-sand-silt mixture. Non-plastic fines.
GC Clayey gravels, gravel-sand-clay mixtures. Plastic fines SANDS
More than half
of coarse
fraction is
smaller than
#4 sieve
Clean Sands
(<5% fines)
SW Well-graded gravels, gravel-sand mixtures, little or no fines.
SP Poorly graded sands or gravelly sands, little or no fines.
Sands with
Fines
SM Silty sands, sand-silt mixtures. Non-Plastic fines.
SC Clayey sands, sand-clay mixtures. Plastic fines.
FINE GRAINED SOILS
More than half of material is
smaller than #200 sieve size
SILTS AND
CLAYS
LIQUID LIMIT
IS LESS THAN
50 ML Inorganic silts and very fine sands, rock flour, silty or clayey fine sands or clayey silts, with slight plasticity
CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays.
OL Organic silts and organic silty clays of low plasticity.
SILTS AND
CLAYS
LIQUID LIMIT
IS GREATER
THAN 50
MH Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts.
CH Inorganic clays of high plasticity, fat clays
OH Organic clays of medium to high plasticity, organic silts.
Highly Organic Soils PT Peat and other highly organic soils.
CLASSIFICATION BASED ON FIELD TESTS
CLASSIFICATION CRITERIA BASED ON LAB TESTS
PENETRATION RESISTANCE (PR)
Sands and Gravels
Relative Density Blows/foot
Very loose 0-4
Loose 4-10
Medium Dense 10-30
Dense 30-50
Very Dense Over 50
Clays and Silts
Consistency Blows/foot* Strength**
Very Soft 0-2 0-½
Soft 2-4 ¼-½
Firm 4-8 ½-1
Stiff 8-15 1-2
Very Stiff 15-30 2-4
Hard Over 30 Over 4
*Numbers of blows of 140 lb hammer
falling 30 inches to drive a 2-inch O.D.
(1 3/8 in. I.D.) Split Barrel sampler
(ASTM-1568 Standard Penetration Test)
**Unconfined Compressive strength in
tons/sq. ft. Read from pocket
penetrometer
Liquid Limit
Plasticity chart for laboratory
Classification of Fine-grained soils
0 10 20 30 40 50 60 70 80 90 100
60 50
40 30
20 10
0 Plasticity Index
Comparing soils at equal liquid limit
Toughness and dry strength increase with
increasing plasticity index
Fines (Silty or Clay) Fine Sand Medium Sand Coarse Sand Fine Gravel Coarse Gravel Cobbles Boulders Sieve Sizes 200 40 10 4 ¾” 3” 10”
GW and SW – Cu= D60/D10 greater than 4 for GW and 6 for SW; Cc = (D30) 2/D10x D60 between 1 and 3
GP and SP – Clean gravel or sand not meeting requirement for GW and SW GM and SM – Atterberg limit below “A” line or P.I. less than 4 GC and SC – Atterberg limit above “A” line P.I. greater than 7
CLASSIFICATION OF EARTH MATERIAL IS BASED ON FIELD INSPECTION
AND SHOULD NOT BE CONSTRUED TO IMPLY LABORATORY ANALYSIS UNLESS SO STATED.
C
L
CL
CL-ML
OH
Or
MH
OL
or
ML ML
CH
GLOBAL GEO-ENGINEERING, INC.
GEOLOGIC AND SOILS ENGINEERING, IRVINE, CALIFORNIA
244 Pico Avenue
San Marcos, California
Date: August 2022
Project No.: 9421-04
Figure No.:
B-1
Global Geo-Engineering, Inc.
Irvine, California
Geologists and Geotechnical Engineers
Project 9421-04
San Marcos, California
244 Pico Avenue
Figure B-2.1
LOG OF BORING B-1
Date : May 17, 2022
Logged By : KBY
Diameter of Boring : 6''
Drilling Company : Cal Pac Drilling
Drilling Rig : Mobile B-61
Drilling Method : Hollow Stem
Sampling Method : California Modified
Hammer Weight (lbs) : 140
Hammer Drop (in) : 30
Depth in Feet
0 5
10 15
20 25
Sample
Field Moisture% Dry Weight
7.6 6.8
12.9 15.0
19.3 15.0
Dry Densitylb./cubic ft.
116.7
112.6
116.2
115.5
109.6
115.4
Blow Count
55 29
100
39 38
23 Relative Compaction
Water Level
USCS
SM
SM/ML
ML
SP
GRAPHIC
DESCRIPTION
Sample Type
Ring
Bulk
Standard Penetration Testing
Water Levels
Groundwater Encountered
Seepage Encountered
Clayey Silty SAND: fine to medium grained, light reddish brown, slightly moist, medium dense
Silty SAND: fine grained, yellow brown, slightly moist, medium dense with SILT interbeds
Clayey SILT: light reddish to reddish brown, slightly moist to moist, stiff
@19' moist
SAND: medium to coarse grained, reddish brown, very moist to wet, medium dense, water encountered
Global Geo-Engineering, Inc.
Irvine, California
Geologists and Geotechnical Engineers
Project 9421-04
San Marcos, California
244 Pico Avenue
Figure B-2.2
LOG OF BORING B-1
Date : May 17, 2022
Logged By : KBY
Diameter of Boring : 6''
Drilling Company : Cal Pac Drilling
Drilling Rig : Mobile B-61
Drilling Method : Hollow Stem
Sampling Method : California Modified
Hammer Weight (lbs) : 140
Hammer Drop (in) : 30
Depth in Feet
25 30
35 40
45 50
Sample
Field Moisture% Dry Weight
19.5 17.2
9.1 Dry Densitylb./cubic ft.
106.0
104.9
129.3
Blow Count
18 12
100
Relative Compaction
Water Level
USCS
SP
SP/ML
GR
GRAPHIC
DESCRIPTION
Sample Type
Ring
Bulk
Standard Penetration Testing
Water Levels
Groundwater Encountered
Seepage Encountered
@29' fine to medium grained with SILT interbeds
@34' medium grained, olive brown
ALLUVIUM
TONALITE: fine textured, hard
BASEMENT ROCK
Bottom of Boring at 40 feet:
Notes:
1. Caving to 23 feet after augers were removed
2. Water encountered at 24', Static water level measured at 23.5'
3. Boring backfilled
Global Geo-Engineering, Inc.
Irvine, California
Geologists and Geotechnical Engineers
Project 9421-04
San Marcos, California
244 Pico Avenue
Figure B-3
LOG OF BORING B-2
Date : May 17, 2022
Logged By : KBY
Diameter of Boring : 6''
Drilling Company : Cal Pac Drilling
Drilling Rig : Mobile B-61
Drilling Method : Hollow Stem
Sampling Method : California Modified
Hammer Weight (lbs) : 140
Hammer Drop (in) : 30
Depth in Feet
0 5
10 15
20 25
Sample
Field Moisture% Dry Weight
13.5 11.0
11.2 14.0
12.0 Dry Densitylb./cubic ft.
113.8
107.2
112.5
114.2
113.4
Blow Count
20 45
35 48
20 Relative Compaction
Water Level
USCS
CL/ML
ML
ML/SM
ML
SM
GRAPHIC
DESCRIPTION
Sample Type
Ring
Bulk
Standard Penetration Testing
Water Levels
Groundwater Encountered
Seepage Encountered
Sandy Silty CLAY: reddish brown, slightly moist, medium stiff with Clayey SILT interbeds
Sandy SILT: yellow to light reddish brown, slightly moist, stiff @9' with Silty SAND interbeds
Clayey SILT: olive gray to light reddish brown, slightly moist, stiff Clayey Silty SAND: fine to medium grained, light reddish brown, moist, medium dense ALLUVIUM
Bottom of Boring at 20 feet:
Notes:
1. Caving to 15.5 feet after augers were removed
2. No groundwater or seepage encountered
3. Boring backfilled
244 Pico Avenue
San Marcos, California
Date: August 2022
Project No.: 9421-04
Figure No:
GLOBAL GEO-ENGINEERING, INC.
GEOLOGIC AND SOILS ENGINEERING IRVINE, CALIFORNIA B-4
BORING LOCATION PLAN
KEY
N
B-2
20’
B-1
39.5 ’
Approximate Location of Boring,
Showing Total Depth
B-2
20’
Not to Scale
Project 9421-04
APPENDIX C
Laboratory Testing Program
The laboratory-testing program was directed towards providing quantitative data relating to the relevant engineering properties of the soils. Samples considered representative of site conditions were tested as described below.
a) Moisture and Density
Moisture-density information usually provides a gross indication of soil consistency.
Local variations at the time of the investigation can be delineated, and a correlation obtained between soils found on this site and nearby sites. The dry unit weights and field moisture contents were determined for selected samples. The results are shown on the Logs of Borings.
b) Compaction
A representative soil sample was tested in the laboratory to determine the maximum dry density and optimum moisture content, using the ASTM D1557 compaction test method.
This test procedure requires 25 blows of a 10-pound hammer falling a height of 18 inches on each of five layers, in a 1/30 cubic foot cylinder. The results of the test are presented below.
Boring No. Sample Depth
(ft.) Soil Description
Optimum
Moisture
Content
(%)
Maximum
Dry Density
(lb/ft3
)
B-1 1-3 Clayey Silty SAND 9.9 127.3
Appendix C
Project 9421-04
c) Direct Shear
Direct shear tests were made on remolded samples, using a direct shear machine at a constant rate of strain. Variable normal or confining loads are applied vertically and the soil shear strengths are obtained at these loads. The angle of internal friction and the cohesion are then evaluated. The samples were tested at saturated moisture contents. The results are shown below in terms of the Coulomb shear strength parameters.
Boring No. Sample Depth
(ft)
Soil
Description
Coulomb
Cohesion
(lb/ft2
)
Angle of
Internal
Friction
(°)
Peak/Residual
B-1 1-3 Clayey Silty SAND 250
250
29 29
Peak
Ultimate
d) Sulfate Content
A representative soil sample was analyzed for its sulphate content. The results are given below:
Boring No. Sample Depth
(ft.) Soil Description Sulphate Content
(%)
B-1 1-3 Clayey Silty SAND 0.0026
e) Chloride Content
A representative soil sample was analyzed for chloride content in accordance with California Test Method CA422. The result is given below:
Boring No. Sample Depth
(ft)
Soil
Description
Chloride Content
(%)
B-1 1-3 Clayey Silty SAND 0.0023
Appendix C
Project 9421-04
f) Resistivity and pH
A representative soil sample was analyzed in accordance with California Test Methods CA532 and CA643 to determine the minimum resistivity and pH. The result is provided below:
Boring No. Sample Depth
(ft)
Soil
Description pH
Minimum
Resistivity
(Ohm-cm)
B-1
1-3 Clayey Silty SAND 8.1 3,339
g) Expansion Potential
Surface soils were collected in the field and tested in the laboratory in accordance with the ASTM Test Designation D4829. The degree of expansion potential is determined from soil volume changes occurring during saturation of the specimen. The results of the tests are presented below:
Boring No. Sample Depth
(ft)
Soil
Description
Expansion
Index
Expansion
Potential
B-2 2 Sandy Silty CLAY 70 Medium
ATTACHMENT 9
Summary Files from the SWMM Model
PRE_DEV
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.0 (Build 5.0.022) --------------------------------------------------------------
********************************************************* NOTE: The summary statistics displayed in this report are based on results found at every computational time step, not just on results from each reporting time step.
*********************************************************
****************
Analysis Options
****************
Flow Units ............... CFS
Process Models:
Rainfall/Runoff ........ YES
Snowmelt ............... NO
Groundwater ............ NO
Flow Routing ........... NO
Water Quality .......... NO
Infiltration Method ...... GREEN_AMPT
Starting Date ............ OCT-05-1962 00:00:00
Ending Date .............. OCT-05-2007 23:00:00
Antecedent Dry Days ...... 0.0
Report Time Step ......... 01:00:00
Wet Time Step ............ 00:15:00
Dry Time Step ............ 04:00:00
************************** Volume Depth
Runoff Quantity Continuity acre-feet inches
************************** --------- -------
Total Precipitation ...... 30.777 547.150
Evaporation Loss ......... 0.477 8.477
Infiltration Loss ........ 28.588 508.225
Surface Runoff ........... 1.944 34.554
Final Surface Storage .... 0.000 0.000
Continuity Error (%) ..... -0.750
************************** Volume Volume
Flow Routing Continuity acre-feet 10^6 gal
************************** --------- ---------
Dry Weather Inflow ....... 0.000 0.000
Wet Weather Inflow ....... 1.944 0.633
Groundwater Inflow ....... 0.000 0.000
RDII Inflow .............. 0.000 0.000
External Inflow .......... 0.000 0.000
External Outflow ......... 1.944 0.633
Internal Outflow ......... 0.000 0.000
Storage Losses ........... 0.000 0.000
Initial Stored Volume .... 0.000 0.000
Final Stored Volume ...... 0.000 0.000
Continuity Error (%) ..... 0.000
***************************
Subcatchment Runoff Summary
***************************
-------------------------------------------------------------------------------------------------------- Total Total Total Total Total Total Peak Runoff
Precip Runon Evap Infil Runoff Runoff Runoff Coeff
Subcatchment in in in in in 10^6 gal CFS
-------------------------------------------------------------------------------------------------------- DMA-1-C 547.15 0.00 8.48 508.22 34.55 0.63 0.47 0.063
Analysis begun on: Sat Nov 05 10:52:00 2022
Analysis ended on: Sat Nov 05 10:52:24 2022
Total elapsed time: 00:00:24
POST_DEV
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.0 (Build 5.0.022) --------------------------------------------------------------
********************************************************* NOTE: The summary statistics displayed in this report are based on results found at every computational time step, not just on results from each reporting time step.
*********************************************************
****************
Analysis Options
****************
Flow Units ............... CFS
Process Models:
Rainfall/Runoff ........ YES
Snowmelt ............... NO
Groundwater ............ NO
Flow Routing ........... YES
Ponding Allowed ........ NO
Water Quality .......... NO
Infiltration Method ...... GREEN_AMPT
Flow Routing Method ...... KINWAVE
Starting Date ............ OCT-05-1962 00:00:00
Ending Date .............. OCT-05-2007 23:00:00
Antecedent Dry Days ...... 0.0
Report Time Step ......... 01:00:00
Wet Time Step ............ 00:15:00
Dry Time Step ............ 04:00:00
Routing Time Step ........ 60.00 sec
************************** Volume Depth
Runoff Quantity Continuity acre-feet inches
************************** --------- -------
Total Precipitation ...... 30.777 547.150
Evaporation Loss ......... 4.429 78.736
Infiltration Loss ........ 7.152 127.142
Surface Runoff ........... 19.497 346.620
Final Surface Storage .... 0.000 0.000
Continuity Error (%) ..... -0.977
************************** Volume Volume
Flow Routing Continuity acre-feet 10^6 gal
************************** --------- ---------
Dry Weather Inflow ....... 0.000 0.000
Wet Weather Inflow ....... 19.497 6.354
Groundwater Inflow ....... 0.000 0.000
RDII Inflow .............. 0.000 0.000
External Inflow .......... 0.000 0.000
External Outflow ......... 2.531 0.825
Internal Outflow ......... 0.000 0.000
Storage Losses ........... 17.144 5.587
Initial Stored Volume .... 0.000 0.000
Final Stored Volume ...... 0.000 0.000
Continuity Error (%) ..... -0.910
********************************
Highest Flow Instability Indexes
********************************
All links are stable.
*************************
Routing Time Step Summary
*************************
Minimum Time Step : 60.00 sec
Average Time Step : 60.00 sec
POST_DEV
Maximum Time Step : 60.00 sec
Percent in Steady State : 0.00
Average Iterations per Step : 1.00
***************************
Subcatchment Runoff Summary
***************************
-------------------------------------------------------------------------------------------------------- Total Total Total Total Total Total Peak Runoff
Precip Runon Evap Infil Runoff Runoff Runoff Coeff
Subcatchment in in in in in 10^6 gal CFS
-------------------------------------------------------------------------------------------------------- DMA-1-C 547.15 0.00 78.74 127.14 346.62 6.35 0.53 0.634
******************
Node Depth Summary
******************
--------------------------------------------------------------------- Average Maximum Maximum Time of Max
Depth Depth HGL Occurrence
Node Type Feet Feet Feet days hr:min
--------------------------------------------------------------------- POC-1 OUTFALL 0.00 0.00 0.00 0 00:00
1 STORAGE 0.05 7.29 7.29 5576 07:03
*******************
Node Inflow Summary
*******************
------------------------------------------------------------------------------------- Maximum Maximum Lateral Total
Lateral Total Time of Max Inflow Inflow
Inflow Inflow Occurrence Volume Volume
Node Type CFS CFS days hr:min 10^6 gal 10^6 gal
------------------------------------------------------------------------------------- POC-1 OUTFALL 0.00 1.92 5576 07:03 0.000 0.825
1 STORAGE 0.53 0.53 6348 00:00 6.353 6.353
**********************
Node Surcharge Summary
**********************
Surcharging occurs when water rises above the top of the highest conduit. --------------------------------------------------------------------- Max. Height Min. Depth
Hours Above Crown Below Rim
Node Type Surcharged Feet Feet
--------------------------------------------------------------------- 1 STORAGE 394487.02 7.292 1.708
*********************
Node Flooding Summary
*********************
No nodes were flooded.
**********************
Storage Volume Summary
**********************
-------------------------------------------------------------------------------------------- Average Avg E&I Maximum Max Time of Max Maximum
Volume Pcnt Pcnt Volume Pcnt Occurrence Outflow
POST_DEV
Storage Unit 1000 ft3 Full Loss 1000 ft3 Full days hr:min CFS -------------------------------------------------------------------------------------------- 1 0.018 1 88 2.643 82 5576 07:03 1.92
***********************
Outfall Loading Summary
***********************
----------------------------------------------------------- Flow Avg. Max. Total
Freq. Flow Flow Volume
Outfall Node Pcnt. CFS CFS 10^6 gal
----------------------------------------------------------- POC-1 0.33 0.02 1.92 0.825
----------------------------------------------------------- System 0.33 0.02 1.92 0.825
********************
Link Flow Summary
********************
----------------------------------------------------------------------------- Maximum Time of Max Maximum Max/ Max/
|Flow| Occurrence |Veloc| Full Full
Link Type CFS days hr:min ft/sec Flow Depth
----------------------------------------------------------------------------- 1 DUMMY 1.92 5576 07:03
*************************
Conduit Surcharge Summary
*************************
No conduits were surcharged.
Analysis begun on: Sat Nov 05 10:53:04 2022
Analysis ended on: Sat Nov 05 10:53:34 2022
Total elapsed time: 00:00:30
Appendix G. Stormwater Quality Management Plan
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CITY OF SAN MARCOS
PRIORITY DEVELOPMENT PROJECT (PDP)
STORM WATER QUALITY MANAGEMENT PLAN (SWQMP)
FOR
PICO PLACE
236‐244 PICO AVENUE
CITY OF SAN MARCOS, CALIFORNIA 92069
ASSESSOR'S PARCEL NUMBER(S):
220‐140‐05‐00 & 220‐140‐16‐00
ENGINEER OF WORK:
___________________________________________________________________________________ Dr. Luis Parra – R.C.E. 66377
PREPARED FOR:
PICO INVESTMENTS 7, LLC.
29250 PASEO SEDANO
SAN JAN CAPISTRANO, CALIFORNIA 92675
(951) 801‐0888
PDP SWQMP PREPARED BY:
REC CONSULTANTS
2442 SECOND AVENUE
SAN DIEGO, CALIFORNIA 92102
(619) 323‐9200
DATE OF SWQMP:
NOVEMBER 6, 2022
Revised APRIL 14, 2023
PLANS PREPARED BY:
DMS CONSULTANTS
12731 LEWIS ST #203
GARDEN GROVE, CALIFORNIA 92840
(714) 740‐8840
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City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
TABLE OF CONTENTS
Acronym Sheet
PDP SWQMP Preparer's Certification Page
PDP SWQMP Project Owner's Certification Page
Submittal Record
Project Vicinity Map
FORM I‐1 Applicability of Storm Water BMP Requirements
FORM I‐2 Project Type Determination Checklist (Standard Project or PDP) FORM I‐3B Site Information Checklist for PDPs
FORM I‐4 Source Control BMP Checklist for All Development Projects FORM I‐5 Site Design BMP Checklist for All Development Projects FORM I‐6 Summary of PDP Structural BMPs
Attachment 1: Backup for PDP Pollutant Control BMPs
Attachment 1a: DMA Exhibit
Attachment 1b: Tabular Summary of DMAs and Design Capture Volume Calculations Attachment 1c: Harvest and Use Feasibility Screening (when applicable) Attachment 1d: Categorization of Infiltration Feasibility Condition (when applicable) Attachment 1e: Pollutant Control BMP Design Worksheets / Calculations Attachment 2: Backup for PDP Hydromodification Control Measures Attachment 2a: Hydromodification Management Exhibit
Attachment 2b: Management of Critical Coarse Sediment Yield Areas Attachment 2c: Geomorphic Assessment of Receiving Channels Attachment 2d: Flow Control Facility Design
Attachment 3: Structural BMP Maintenance Plan
Attachment 3a: B Structural BMP Maintenance Thresholds and Actions Attachment 3b: Draft Maintenance Agreement (when applicable) Attachment 4: Copy of Plan Sheets Showing Permanent Storm Water BMPs
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City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
ACRONYMS
APN Assessor's Parcel Number
BMP Best Management Practice
HMP Hydromodification Management Plan
HSG Hydrologic Soil Group
MS4 Municipal Separate Storm Sewer System
N/A Not Applicable
NRCS Natural Resources Conservation Service
PDP Priority Development Project
PE Professional Engineer
SC Source Control
SD Site Design
SDRWQCB San Diego Regional Water Quality Control Board
SIC Standard Industrial Classification
SWQMP Storm Water Quality Management Plan
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City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
PDP SWQMP PREPARER'S CERTIFICATION PAGE
Project Name: Pico Place
Permit Application Number: GPA22‐0005
PREPARER'S CERTIFICATION
I hereby declare that I am the Engineer in Responsible Charge of design of storm water best management practices (BMPs) for this project, and that I have exercised responsible charge over the design of the BMPs as defined in Section 6703 of the Business and Professions Code, and that the design is consistent with the PDP requirements of the County of San Diego BMP Design Manual, which is a design manual for compliance with local City of San Marcos and regional MS4 Permit (California Regional Water Quality Control Board San Diego Region Order No. R9‐2015‐0100) requirements for storm water management.
I have read and understand that the [City Engineer] has adopted minimum requirements for managing urban runoff, including storm water, from land development activities, as described in the BMP Design Manual. I certify that this PDP SWQMP has been completed to the best of my ability and accurately reflects the project being proposed and the applicable BMPs proposed to minimize the potentially negative impacts of this project's land development activities on water quality. I understand and acknowledge that the plan check review of this PDP SWQMP by the [City Engineer] is confined to a review and does not relieve me, as the Engineer in Responsible Charge of design of storm water BMPs for this project, of my responsibilities for project design. ______________________________RCE 66377 Exp 6‐30‐24______ Engineer of Work's Signature, PE Number & Expiration Date ________________________________________________________ Dr. Luis A. Parra
________________________________________________________ REC‐Consultants
4/14/23
____________________________
Date
Engineer's Seal:
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City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
PDP SWQMP PROJECT OWNER'S CERTIFICATION PAGE
Project Name: Pico Place
Permit Application Number: GPA22‐0005
PROJECT OWNER'S CERTIFICATION
This PDP SWQMP has been prepared for Pico Investments 7, LLC by REC Consultants, Inc. The PDP SWQMP is intended to comply with the PDP requirements of the County of San Diego BMP Design Manual, which is a design manual for compliance with the 2013 Municipal Storm Water Permit and regional MS4 Permit (California Regional Water Quality Control Board San Diego Region Order No. R9‐ 2015‐0100) requirements for storm water management.
The undersigned, while it owns the subject property, is responsible for the implementation of the provisions of this plan. Once the undersigned transfers its interests in the property, its successor‐in‐ interest shall bear the aforementioned responsibility to implement the best management practices (BMPs) described within this plan, including ensuring on‐going operation and maintenance of structural BMPs. A signed copy of this document shall be available on the subject property into perpetuity. ________________________________________________________ Project Owner's Signature
________________________________________________________ Print Name
________________________________________________________ Company
____________________________
Date
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City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
SUBMITTAL RECORD
Use this Table to keep a record of submittals of this PDP SWQMP. Each time the PDP SWQMP is re‐ submitted, provide the date and status of the project. In column 4 summarize the changes that have been made or indicate if response to plancheck comments is included. When applicable, insert response to plancheck comments behind this page.
Submittal
Number
Date Project Status Summary of Changes
1 November 6, 2022 ☒Preliminary Design /
Planning/ CEQA
☐ Final Design
Initial Submittal
2 February 21, 2023 ☒Preliminary Design /
Planning/ CEQA
☐ Final Design
2nd submittal
3 April 14, 2023 ☒Preliminary Design /
Planning/ CEQA
☐ Final Design
3rd submittal
4 ☐Preliminary Design /
Planning/ CEQA
☐ Final Design
5 ☐Preliminary Design /
Planning/ CEQA
☐ Final Design
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City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
PROJECT VICINITY MAP
Project Name: Pico Place
Permit Application Number: GPA22‐0005
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1 City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Applicability of Storm Water Best Management Practices (BMP) Requirements
(Storm Water Intake Form for all Development Permit Applications) For detailed information please visit:
http://www.san‐marcos.net/departments/development‐services/stormwater/development‐ planning
Form I‐1
[March 15, 2016]
Project Identification
Project Name: Pico Place
Description: Multi‐family residential development
Permit Application Number (if applicable): GPA22‐0005 Date: November 6, 2022
Project Address: 236‐244 Pico Avenue, San Marcos, CA 92069 Determination of Requirements
This form is required as part of the City’s application process. The purpose of this form is to identify potential land development planning storm water requirements that apply to development projects.
Development projects are defined as construction, rehabilitation, redevelopment, or reconstruction of any public or private projects. In addition, the identification of a development project, as it relates to storm water regulations, would truly apply to development and redevelopment activities that have the potential to contact storm water and contribute a source of pollutants, or reduce the natural absorption and infiltration abilities of the land.
To access the BMP Design Manual, Storm Water Quality Management Plan (SWQMP) templates, and other pertinent information related to this program please refer to:
http://www.san‐marcos.net/departments/development‐services/stormwater/development‐planning Please answer each of the following steps below, starting with Step 1 and progressing through each step until reaching "Stop".
Step Answer Progression
Step 1: Based on the above, Is the project a
"development project" (See definition above)?
See Section 1.3 of the BMP Design Manual for
further guidance if necessary.
☒ Yes Go to Step 2.
No Permanent BMP requirements do not apply. No
SWQMP will be required. Provide brief discussion
below. STOP.
Discussion / justification if the project is not a "development project" (e.g., the project includes only interior remodels within an existing building):
Step 2: Is the project a Standard Project,
Priority Development Project (PDP), or
exception to PDP definitions?
To answer this item, complete Form I‐2,
Project Type Determination. See Section 1.4
of the BMP Design Manual in its entirety for
guidance.
In addition to Section 1.4, please refer to the
City’s SWQMP Submittal Requirements form.
Standard Project Only Standard Project requirements apply, including Standard Project SWQMP. STOP.
☒PDP Standard and PDP requirements apply, including
PDP SWQMP. Go to Step 3 on the following
page.
Exception to PDP
definitions
Standard Project requirements apply, and
any additional requirements specific to the
type of project. Provide discussion and list
any additional requirements below. Prepare
Standard Project SWQMP. STOP.
Discussion / justification, and additional requirements for exceptions to PDP definitions, if applicable:
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I-1 Page 2, Form Date: March 15, 2016
Step 3 (PDPs only). Please answer the list of questions in this section to determine if hydromodification requirements reply to the proposed PDP. Does the project:
Step 3a. Discharge
storm water runoff directly
to the Pacific Ocean?
☐ Yes STOP. Hydromodification requirements do not apply. ☒ No Continue to Step 3b.
Step 3b. Discharge
storm water runoff directly
to an enclosed
embayment, not within
protected areas?
☐ Yes STOP. Hydromodification requirements do not apply. ☒ No Continue to Step 3c.
Step 3c. Discharge
storm water runoff directly
to a water storage
reservoir or lake, below
spillway or normal
operating level?
☐ Yes STOP. Hydromodification requirements do not apply. ☒ No Continue to Step 3d.
Step 3d. Discharge
storm water runoff directly
to an area identified in
WMAA?
☐ Yes STOP. Hydromodification requirements do not apply. ☒ No Hydromodification requirements apply to the project.
Go to Step 4.
Discussion / justification if hydromodification control requirements do not apply:
Step 4 (PDPs subject to
hydromodification
control requirements
only). Does protection of
critical coarse sediment
yield areas apply based
on review of WMAA
Potential Critical Coarse
Sediment Yield Area
Map?
See Section 6.2 of the
BMP Design Manual for
guidance.
☐ Yes Management measures required for protection of critical coarse sediment yield areas (Chapter 6.2).
Stop.
☒ No Management measures not required for protection of critical coarse sediment yield areas.
Provide brief discussion below.
Stop.
*Project site is not located in, or adjacent to Critical coarse sediment yield areas.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Project Type Determination Checklist Form I‐2
[March 15, 2016]
Project Information
Project Name/Description: Pico Place
Permit Application Number (if applicable): GPA22‐0005 Date: November 6, 2022 Project Address: 236‐244 Pico Avenue, San Marcos, CA 92069 Project Type Determination: Standard Project or Priority Development Project (PDP) The project is (select one): ☒ New Development ☐ Redevelopment The total proposed newly created or replaced impervious area is: 21,975 ft2 (0.504 acres) Is the project in any of the following categories, (a) through (f)? Yes
☒
No
☐
(a) New development projects that create 10,000 square feet or more of impervious surfaces (collectively over the entire project site). This includes commercial, industrial, residential, mixed‐use, and public development projects on public or private land.
Yes
☐
No
☒
(b) Redevelopment projects that create and/or replace 5,000 square feet or more of impervious surface (collectively over the entire project site on an existing site of 10,000 square feet or more of impervious surfaces). This includes commercial, industrial, residential, mixed‐use, and public development projects on public or private land.
Yes
☒
No
☐
(c) New and redevelopment projects that create and/or replace 5,000 square feet or more of impervious surface (collectively over the entire project site), and support one or more of the following uses:
(i) Restaurants. This category is defined as a facility that sells prepared foods and drinks for consumption, including stationary lunch counters and refreshment stands selling prepared foods and drinks for immediate consumption (Standard Industrial Classification (SIC) code 5812). (ii) Hillside development projects. This category includes development on any natural slope that is twenty‐five percent or greater.
(iii) Parking lots. This category is defined as a land area or facility for the temporary parking or storage of motor vehicles used personally, for business, or for commerce.
(iv) Streets, roads, highways, freeways, and driveways. This category is defined as any paved impervious surface used for the transportation of automobiles, trucks, motorcycles, and other vehicles.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐2 Page 2, Form Date: March 15, 2016
Yes
☐
No
☒
(d) New or redevelopment projects that create and/or replace 2,500 square feet or more of impervious surface (collectively over the entire project site), and discharging directly to an Environmentally Sensitive Area (ESA). “Discharging directly to” includes flow that is conveyed overland a distance of 200 feet or less from the project to the ESA, or conveyed in a pipe or open channel any distance as an isolated flow from the project to the ESA (i.e. not commingled with flows from adjacent lands).
Note: ESAs are areas that include but are not limited to all Clean Water Act Section 303(d) impaired water bodies; areas designated as Areas of Special Biological Significance by the State Water Board and San Diego Water Board; State Water Quality Protected Areas; water bodies designated with the RARE beneficial use by the State Water Board and San Diego Water Board; and any other equivalent environmentally sensitive areas which have been identified by the Copermittees. See BMP Design Manual Section 1.4.2 for additional guidance.
Yes
☐
No
☒
(e) New development projects, or redevelopment projects that create and/or replace 5,000 square feet or more of impervious surface, that support one or more of the following uses:
(i) Automotive repair shops. This category is defined as a facility that is categorized in any one of the following SIC codes: 5013, 5014, 5541, 7532‐ 7534, or 7536‐7539.
(ii) Retail gasoline outlets (RGOs). This category includes RGOs that meet the following criteria: (a) 5,000 square feet or more or (b) a projected Average Daily Traffic (ADT) of 100 or more vehicles per day.
Yes
☐
No
☒
(f) New or redevelopment projects that result in the disturbance of one or more acres of land and are expected to generate pollutants post construction.
Note: See BMP Design Manual Section 1.4.2 for additional guidance.
Does the project meet the definition of one or more of the Priority Development Project categories (a) through (f) listed above?
☐ No – the project is not a Priority Development Project (Standard Project). ☒ Yes – the project is a Priority Development Project (PDP).
The following is for redevelopment PDPs only:
The area of existing (pre‐project) impervious area at the project site is: ________ ft2 (A) The total proposed newly created or replaced impervious area is ________ ft2 (B) Percent impervious surface created or replaced (B/A)*100: _______% The percent impervious surface created or replaced is (select one based on the above calculation):
less than or equal to fifty percent (50%) – only new impervious areas are considered PDP OR
greater than fifty percent (50%) – the entire project site is a PDP
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Site Information Checklist
For PDPs
Form I‐3B (PDPs)
[March 15, 2016]
Project Summary Information
Project Name Pico Place
Project Address 236‐244 Pico Avenue, San Marcos, CA 92069 Assessor's Parcel Number(s) (APN(s)) 220‐140‐05‐00, 220‐140‐16‐00 Permit Application Number GPA22‐0005
Project Hydrologic Unit Select One:
☐ Santa Margarita 902
☐ San Luis Rey 903
☒ Carlsbad 904
☐ San Dieguito 905
☐ Penasquitos 906
☐ San Diego 907
☐ Pueblo San Diego 908
☐ Sweetwater 909
☐ Otay 910
☐ Tijuana 911
Project Watershed(Complete Hydrologic Unit,
Area, and Subarea Name with Numeric
Identifier)
Carlsbad Hydrologic Unit (904)
San Marcos Hydrologic Area (904.5)
Richland Hydraulic Sub‐Area (904.52)
Parcel Area
(total area of Assessor's Parcel(s) associated
with the project)
0.675 Acres (29,403 Square Feet)
Area to be Disturbed by the Project
(Project Area) 0.675 Acres (29,403 Square Feet)
Project Proposed Impervious Area
(subset of Project Area) 0.504 Acres (21,975 Square Feet) Project Proposed Pervious Area
(subset of Project Area) 0.17 Acres (7,407 Square Feet) Note: Proposed Impervious Area + Proposed Pervious Area = Area to be Disturbed by the Project.
This may be less than the Parcel Area.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐3B Page 2 of 10, Form Date: March 15, 2016
Description of Existing Site Condition
Current Status of the Site (select all that apply):
☒Existing development
☒ Previously graded but not built out
☐ Demolition completed without new construction
☐ Agricultural or other non‐impervious use
☐ Vacant, undeveloped/natural
Description / Additional Information:
The existing project site comprises of a developed single‐family residence and an adjoining graded, undeveloped lot.
Existing Land Cover Includes (select all that apply):
☐ Vegetative Cover
☒ Non‐Vegetated Pervious Areas
☒ Impervious Areas
Description / Additional Information:
The existing site incorporates a single residential structure, garage and paved driveway.
Underlying Soil belongs to Hydrologic Soil Group (select all that apply):
☐ NRCS Type A
☐ NRCS Type B
☒ NRCS Type C
☐ NRCS Type D
Approximate Depth to Groundwater (GW):
☐ GW Depth < 5 feet
☐ 5 feet < GW Depth < 10 feet
☐ 10 feet < GW Depth < 20 feet
☒ GW Depth > 20 feet
Existing Natural Hydrologic Features (select all that apply):
☐ Watercourses
☐ Seeps
☐ Springs
☐ Wetlands
☒ None
Description / Additional Information:
The existing site has no natural existing hydrological features.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐3B Page 3 of 10, Form Date: March 15, 2016
Description of Existing Site Drainage Patterns
How is storm water runoff conveyed from the site? At a minimum, this description should answer:
(1) whether existing drainage conveyance is natural or urban; (2) Is runoff from offsite conveyed through the site? if yes, quantify all offsite drainage areas, design flows, and locations where offsite flows enter the project site, and summarize how such flows are conveyed through the site;
(3)Provide details regarding existing project site drainage conveyance network, including any existing storm drains, concrete channels, swales, detention facilities, storm water treatment facilities, natural or constructed channels; and
(4) Identify all discharge locations from the existing project site along with a summary of conveyance system size and capacity for each of the discharge locations. Provide summary of the pre‐project drainage areas and design flows to each of the existing runoff discharge locations.
Describe existing site drainage patterns:
In existing conditions, the Pico Place project site is a developed residential lot featuring a single residential structure including several paved surface areas with an adjoining undeveloped lot to the north that is sparsely vegetated.
Runoff from the existing site flows overland to two (2) points of discharge; POC‐1, an existing RCP storm drain located at the eastern boundary of the project site within Pico Avenue and POC‐2, the westerly boundary of the site. The project site ultimately drains to the San Marcos Creek located to the south of the project site. The following table shows the existing condition flows discharging from the project site (and adjacent run‐on from a neighboring site to the west of the project site).
SUMMARY OF EXISTING ONSITE CONDITION FLOWS
Discharge Location Drainage Area
(Ac) 100‐Year Peak Flow (cfs)
Pico Avenue Storm Drain
(POC‐1) 0.234 1.57
Western Property Boundary
(POC‐2) 0.44 0.67
Please refer to the “TM Drainage Study for Pico Place” by REC Consultants dated April 2023 for further details and calculations.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐3B Page 4 of 10, Form Date: March 15, 2016
Description of Proposed Site Development
Project Description / Proposed Land Use and/or Activities:
The proposed project consists of a multi‐family development including landscaped open space, sidewalks and an access drive.
List/describe proposed impervious features of the project (e.g., buildings, roadways, parking lots, courtyards, athletic courts, other impervious features):
Proposed impervious surfaces include: buildings, roadways, parking lots, and sidewalks.
List/describe proposed pervious features of the project (e.g., landscape areas):
Proposed pervious features include: landscape areas.
Does the project include grading and changes to site topography? ☒ Yes
☐ No
Description / Additional Information:
Proposed grading activities are such that project runoff will be conveyed both overland and through a storm drain network to one (1) proposed BMP. Runoff will reach the project’s point of discharge (POC‐1) as in existing conditions.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐3B Page 5 of 10, Form Date: March 15, 2016
Description of Proposed Site Drainage Patterns
Does the project include changes to site drainage (e.g., installation of new storm water conveyance systems)?
☒ Yes
☐ No
If yes, provide details regarding the proposed project site drainage conveyance network, including storm drains, concrete channels, swales, detention facilities, storm water treatment facilities, natural or constructed channels, and the method for conveying offsite flows through or around the proposed project site. Identify all discharge locations from the proposed project site along with a summary of the conveyance system size and capacity for each of the discharge locations. Provide a summary of pre‐ and post‐project drainage areas and design flows to each of the runoff discharge locations. Reference the drainage study for detailed calculations.
Describe proposed site drainage patterns::
The Pico Place project proposes the construction of multi‐ family residences, inclusive of a servicing drive and associated landscaping. Runoff from the project is drained to one (1) receiving multiple purpose water quality/HMP/Q100 detention vault. Detained flows are drained from the BMP facility and discharged to the existing storm drain system within the adjacent Pico Avenue.
Peak developed flows from the project site are conveyed to one (1) onsite detention facility prior to discharging to the existing storm drain system. The vault system is approximately 9‐feet deep with a width of 9‐feet and length of 54‐feet. Due to the limited grade on the project site and utility constraints, the vault is to be located several feet below the existing storm drain invert in Pico Avenue such that the vault can only be drained via the use of pumps. Due to HMP criteria, two (2) separate pumps will be employed on the project site, a low flow pump outlet will be located at 3.0 feet from the bottom of the basin invert while the peak Q100 flow pump will be located at 7.25 feet from the basin invert. In an extreme event, flows will outlet via the surface private drive to Pico Avenue without risk of flooding the residential structures and also providing single vehicular lane access.
SUMMARY OF ONSITE PEAK FLOWS
Discharge
Location
Area (ac) 100 Year Peak Flow (cfs)
Existing Developed Difference Existing Developed Difference POC‐1 0.234 0.674 +0.44 1.57 1.50 ‐0.07
POC‐2 0.44 0.0 ‐0.44 0.67 0.00 ‐0.67
As shown in the above table, the proposed Pico Place project site will result in a decrease of peak flows discharged from the project site by approximately 0.07cfs at POC‐1 while fully removing flows tributary to the western boundary location POC‐2.
Please refer to the “TM Drainage Study for Pico Place” by REC Consultants dated April 2023 for further details and calculations.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐3B Page 6 of 10, Form Date: March 15, 2016
Identify whether any of the following features, activities, and/or pollutant source areas will be present (select all that apply):
☒ On‐site storm drain inlets
☒ Interior floor drains and elevator shaft sump pumps
☒ Interior parking garages
☐ Need for future indoor & structural pest control
☒ Landscape/Outdoor Pesticide Use
☐ Pools, spas, ponds, decorative fountains, and other water features ☐ Food service
☒ Refuse areas
☐ Industrial processes
☐ Outdoor storage of equipment or materials
☐ Vehicle and Equipment Cleaning
☐ Vehicle/Equipment Repair and Maintenance
☐ Fuel Dispensing Areas
☐ Loading Docks
☐ Fire Sprinkler Test Water
☐ Miscellaneous Drain or Wash Water
☒ Plazas, sidewalks, and parking lots
Description / Additional Information:
On site Storm Drains
Onsite storm drain inlets will be stenciled with prohibitive language in accordance with County Requirements. Inlet markings will be maintained and periodically repainted or replaces when necessary.
Storm water pollution prevention information will be provided to new site owners, lessees, or operators. The following will be included in in lease agreements “Tenants shall not allow anyone to discharge anything to storm drains or to store or deposit materials so as to create a potential discharge to storm drains.”
Landscape/Outdoor Pesticide Use
Any pesticides (indoor or outdoor) shall be applied in accordance with the manufacturer instructions and not within 72 hours of an actual or predicted rain event. Landscaping will be maintained using minimum or no pesticides. Provide information to new owners, lessees, and operators.
Refuse Area
Garbage bins will remain covered when not in use. No hazardous materials will be placed inside the bins.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐3B Page 6 of 10, Form Date: March 15, 2016
Description / Additional Information Continuation:
Plazas, sidewalks, and parking lots
Runoff from plazas, sidewalks and parking lots will be collected by the onsite storm drain system and conveyed to the proposed infiltration BMP to address water quality and hydromodification prior to offsite discharge. Plazas, sidewalks, and parking lots will be swept regularly to prevent the accumulation of litter and debris.
The following features are not part of the subject development:
Outdoor material/equipment storage, food service and vehicle/equipment cleaning, repair and/or maintenance.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐3B Page 7 of 10, Form Date: March 15, 2016
Identification and Narrative of Receiving Water and Pollutants of Concern Describe flow path of storm water from the project site discharge location(s), through urban storm conveyance systems as applicable, to receiving creeks, rivers, and lagoons as applicable, and ultimate discharge to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable):
Project runoff will be conveyed via proposed urban storm conveyance network to the adjacent San Marcos Creek, located to the south of the project site. The San Marcos Creek ultimately discharges into San Marcos Lake.
List any 303(d) impaired water bodies within the path of storm water from the project site to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable), identify the pollutant(s)/stressor(s) causing impairment, and identify any TMDLs and/or Highest Priority Pollutants from the WQIP for the impaired water bodies:
303(d) Impaired Water Body Pollutant(s)/Stressor(s)
TMDLs / WQIP Highest Priority
Pollutant
San Marcos Creek
DDE, Phosphorous, Sediment
Toxicity, Selenium, TDS,
Turbidity
Nutrients
San Marcos Lake Ammonia as Nitrogen, Nutrients,
Phosphorous Nutrients
Identification of Project Site Pollutants*
*Identification of project site pollutants is only required if flow‐thru treatment BMPs are implemented onsite in lieu of retention or biofiltration BMPs (note the project must also participate in an alternative compliance program unless prior lawful approval to meet earlier PDP requirements is demonstrated)
Identify pollutants expected from the project site based on all proposed use(s) of the site (see BMP Design Manual Appendix B.6):
Pollutant
Not Applicable to the
Project Site
Expected from the
Project Site
Also a Receiving Water
Pollutant of Concern
Sediment ☐ ☐ ☐
Nutrients ☐ ☐ ☐
Heavy Metals ☐ ☐ ☐
Organic Compounds ☐ ☐ ☐
Trash & Debris ☐ ☐ ☐
Oxygen Demanding
Substances ☐ ☐ ☐
Oil & Grease ☐ ☐ ☐
Bacteria & Viruses ☐ ☐ ☐
Pesticides ☐ ☐ ☐
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐3B Page 8 of 10, Form Date: March 15, 2016
Hydromodification Management Requirements
Do hydromodification management requirements apply (see Section 1.6 of the BMP Design Manual)? ☒ Yes, hydromodification management flow control structural BMPs required. ☐ No, the project will discharge runoff directly to existing underground storm drains discharging directly to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean. ☐ No, the project will discharge runoff directly to conveyance channels whose bed and bank are concrete‐lined all the way from the point of discharge to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean.
☐ No, the project will discharge runoff directly to an area identified as appropriate for an exemption by the WMAA for the watershed in which the project resides.
Description / Additional Information (to be provided if a 'No' answer has been selected above):
Please refer to the HMP Technical Memo for Pico Place by REC Consultants, November 2022.
Critical Coarse Sediment Yield Areas*
*This Section only required if hydromodification management requirements apply Based on the maps provided within the WMAA, do potential critical coarse sediment yield areas exist within the project drainage boundaries?
☐ Yes
☒ No, No critical coarse sediment yield areas to be protected based on WMAA maps If yes, have any of the optional analyses presented in Section 6.2 of the BMP Design Manual been performed?
6.2.1 Verification of Geomorphic Landscape Units (GLUs) Onsite
6.2.2 Downstream Systems Sensitivity to Coarse Sediment
6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite No optional analyses performed, the project will avoid critical coarse sediment yield areas identified based on WMAA maps
If optional analyses were performed, what is the final result? No critical coarse sediment yield areas to be protected based on verification of GLUs onsite Critical coarse sediment yield areas exist but additional analysis has determined that protection is not required. Documentation attached in Attachment 2.b of the SWQMP.
Critical coarse sediment yield areas exist and require protection. The project will implement management measures described in Sections 6.2.4 and 6.2.5 as applicable, and the areas are identified on the SWQMP Exhibit.
Discussion / Additional Information:
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐3B Page 9 of 10, Form Date: March 15, 2016
Flow Control for Post‐Project Runoff*
*This Section only required if hydromodification management requirements apply List and describe point(s) of compliance (POCs) for flow control for hydromodification management (see Section 6.3.1). For each POC, provide a POC identification name or number correlating to the project's HMP Exhibit and a receiving channel identification name or number correlating to the project's HMP Exhibit.
POC‐1 is an existing RCP pipe located at the south‐east boundary of the project site adjacent to the project site within Pico Avenue. Please refer to the site specific HMP memo prepared for the project site for further information.
Has a geomorphic assessment been performed for the receiving channel(s)? ☒ No, the low flow threshold is 0.1Q2 (default low flow threshold) ☐ Yes, the result is the low flow threshold is 0.1Q2
☐ Yes, the result is the low flow threshold is 0.3Q2
☐ Yes, the result is the low flow threshold is 0.5Q2
If a geomorphic assessment has been performed, provide title, date, and preparer:
Discussion / Additional Information: (optional)
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐3B Page 10 of 10, Form Date: March 15, 2016
Other Site Requirements and Constraints
When applicable, list other site requirements or constraints that will influence storm water management design, such as zoning requirements including setbacks and open space, or local codes governing minimum street width, sidewalk construction, allowable pavement types, and drainage requirements.
Optional Additional Information or Continuation of Previous Sections As Needed This space provided for additional information or continuation of information from previous sections as needed.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
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City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Source Control BMP Checklist
for All Development Projects
(Standard Projects and Priority Development Projects)
Form I‐4
[March 15, 2016]
Project Identification
Project Name: Pico Place
Permit Application Number: GPA22‐0005
Source Control BMPs
All development projects must implement source control BMPs SC‐1 through SC‐6 where applicable and feasible. See Chapter 4 and Appendix E of the Model BMP Design Manual for information to implement source control BMPs shown in this checklist.
Answer each category below pursuant to the following.
"Yes" means the project will implement the source control BMP as described in Chapter 4 and/or Appendix E of the Model BMP Design Manual. Discussion / justification is not required. "No" means the BMP is applicable to the project but it is not feasible to implement. Discussion / justification must be provided.
"N/A" means the BMP is not applicable at the project site because the project does not include the feature that is addressed by the BMP (e.g., the project has no outdoor materials storage areas).
Discussion / justification may be provided.
Source Control Requirement Applied?
SC‐1 Prevention of Illicit Discharges into the MS4 ☒ Yes ☐ No ☐ N/A Discussion / justification if SC‐1 not implemented:
SC‐2 Storm Drain Stenciling or Signage ☒ Yes ☐ No ☐ N/A Discussion / justification if SC‐2 not implemented:
SC‐3 Protect Outdoor Materials Storage Areas from Rainfall, Run‐On, Runoff, and Wind Dispersal
☐ Yes ☐ No ☒ N/A
Discussion / justification if SC‐3 not implemented:
No outdoor materials storage areas are proposed.
SC‐4 Protect Materials Stored in Outdoor Work Areas from Rainfall, Run‐On, Runoff, and Wind Dispersal
☐ Yes ☐ No ☒ N/A
Discussion / justification if SC‐4 not implemented:
No outdoor work areas proposed.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐4 Page 2 of 2, Form Date: March 15, 2016
Source Control Requirement Applied?
SC‐5 Protect Trash Storage Areas from Rainfall, Run‐On, Runoff, and Wind Dispersal
☒ Yes ☐ No ☐ N/A
Discussion / justification if SC‐5 not implemented:
SC‐6 Additional BMPs Based on Potential Sources of Runoff Pollutants (must answer for each source listed below)
☒ On‐site storm drain inlets
☐ Interior floor drains and elevator shaft sump pumps
☒ Interior parking garages
☐ Need for future indoor & structural pest control
☒ Landscape/Outdoor Pesticide Use
☐ Pools, spas, ponds, decorative fountains, and other water features ☐ Food service
☒ Refuse areas
☐ Industrial processes
☐ Outdoor storage of equipment or materials
☐ Vehicle and Equipment Cleaning
☐ Vehicle/Equipment Repair and Maintenance
☐ Fuel Dispensing Areas
☐ Loading Docks
☐ Fire Sprinkler Test Water
☐ Miscellaneous Drain or Wash Water
☒ Plazas, sidewalks, and parking lots
☒ Yes
☐ Yes
☒ Yes
☐ Yes
☒ Yes
☐ Yes
☐ Yes
☒ Yes
☐ Yes
☐ Yes
☐ Yes
☐ Yes
☐ Yes
☐ Yes
☐ Yes
☐ Yes
☒ Yes
☐ No
☐ No
☐ No
☐ No
☐ No
☐ No
☐ No
☐ No
☐ No
☐ No
☐ No
☐ No
☐ No
☐ No
☐ No
☐ No
☐ N/A
☒ N/A
☐ N/A
☒ N/A
☐ N/A
☒ N/A
☒ N/A
☐ N/A
☒ N/A
☒ N/A
☒ N/A
☒ N/A
☒ N/A
☒ N/A
☒ N/A
☐ N/A
Discussion / justification if SC‐6 not implemented. Clearly identify which sources of runoff pollutants are discussed. Justification must be provided for all "No" answers shown above.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Site Design BMP Checklist
for All Development Projects
(Standard Projects and Priority Development Projects)
Form I‐5
[March 15, 2016]
Project Identification
Project Name: Pico Place
Permit Application Number: GPA22‐0005
Site Design BMPs
All development projects must implement site design BMPs SD‐1 through SD‐8 where applicable and feasible. See Chapter 4 and Appendix E of the Model BMP Design Manual for information to implement site design BMPs shown in this checklist.
Answer each category below pursuant to the following.
"Yes" means the project will implement the site design BMP as described in Chapter 4 and/or Appendix E of the Model BMP Design Manual. Discussion / justification is not required. "No" means the BMP is applicable to the project but it is not feasible to implement. Discussion / justification must be provided.
"N/A" means the BMP is not applicable at the project site because the project does not include the feature that is addressed by the BMP (e.g., the project site has no existing natural areas to conserve).
Discussion / justification may be provided.
Site Design Requirement Applied?
SD‐1 Maintain Natural Drainage Pathways and Hydrologic Features ☐ Yes ☐ No ☒ N/A Discussion / justification if SD‐1 not implemented:
No existing hydrologic features exist on the project site.
SD‐2 Conserve Natural Areas, Soils, and Vegetation ☒ Yes ☐ No ☐ N/A Discussion / justification if SD‐2 not implemented:
SD‐3 Minimize Impervious Area ☒ Yes ☐ No ☐ N/A
Discussion / justification if SD‐3 not implemented:
SD‐4 Minimize Soil Compaction ☒ Yes ☐ No ☐ N/A
Discussion / justification if SD‐4 not implemented:
SD‐5 Impervious Area Dispersion ☒ Yes ☐ No ☐ N/A
Discussion / justification if SD‐5 not implemented:
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐5 Page 2 of 2, Form Date: March 15, 2016
Site Design Requirement Applied?
SD‐6 Runoff Collection ☐ Yes ☐ No ☒ N/A
Discussion / justification if SD‐6 not implemented:
Other BMPS are employed on the project site. An infiltration BMP is proposed in addition to the site design BMPs already included on the site. Also Harvest and use deemed infeasible per Worksheet 3‐1 (Attachment 1)
SD‐7 Landscaping with Native or Drought Tolerant Species ☒ Yes ☐ No ☐ N/A Discussion / justification if SD‐7 not implemented:
SD‐8 Harvesting and Using Precipitation ☐ Yes ☐ No ☒ N/A Discussion / justification if SD‐8 not implemented:
Harvest and use deemed infeasible per Worksheet 3‐1 (Attachment 1)
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Summary of PDP Structural BMPs Form I‐6 (PDPs)
[March 15, 2016]
Project Identification
Project Name: Pico Place
Permit Application Number: GPA22‐0005
PDP Structural BMPs
All PDPs must implement structural BMPs for storm water pollutant control (see Chapter 5 of the BMP Design Manual). Selection of PDP structural BMPs for storm water pollutant control must be based on the selection process described in Chapter 5. PDPs subject to hydromodification management requirements must also implement structural BMPs for flow control for hydromodification management (see Chapter 6 of the BMP Design Manual). Both storm water pollutant control and flow control for hydromodification management can be achieved within the same structural BMP(s).
PDP structural BMPs must be verified by the local jurisdiction at the completion of construction. This may include requiring the project owner or project owner's representative and engineer of record to certify construction of the structural BMPs (see Section 1.12 of the BMP Design Manual). PDP structural BMPs must be maintained into perpetuity, and the local jurisdiction must confirm the maintenance (see Section 7 of the BMP Design Manual).
Use this form to provide narrative description of the general strategy for structural BMP implementation at the project site in the box below. Then complete the PDP structural BMP summary information sheet (page 3 of this form) for each structural BMP within the project (copy the BMP summary information page as many times as needed to provide summary information for each individual structural BMP).
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Describe the general strategy for structural BMP implementation at the site. This information must describe how the steps for selecting and designing storm water pollutant control BMPs presented in Section 5.1 of the BMP Design Manual were followed, and the results (type of BMPs selected). For projects requiring hydromodification flow control BMPs, indicate whether pollutant control and flow control BMPs are integrated or separate.
The project site was delineated by DMA per Section 3.3.3. There was a total of one (1) DMA delineated.
The DCV of this DMA was calculated per Appendix B.1.
Runoff from the developed project site drains via an onsite storm drain to an underground storage vault.
Prior to discharging to the vault system, runoff is intercepted by an upstream hydro‐dynamic separator unit to screen larger particles & trash and debris that could potentially impact the underground vault’s outlet structure or reduce the infiltration ability of the underlying soil. The detention vault is approximately 9’ x 54’ x 9’ in dimension and due to site elevation constraints, all flows will drain from the underground BMP via two (2) pumps. The lower 3.0’ of the detention vault has been allocated for the DCV which will fully infiltrate into the underlying soils (onsite geotechnical investigation measured an infiltration rate of 3 in/hr which has been factored to a design infiltration rate of 1.37 in/hr). As such, 100% of the DCV will be infiltrated into the underlying soil.
The vaults feature a 24‐inch opening per vault section that allow runoff volume to drain to an underlying base of gravel located beneath the concrete structure such that the contact infiltration area with the soil is the total footprint area of the vault.
Per Worksheet B.3‐1, it was determined that the implementation of Harvest and Use BMPs is infeasible. (Continue on page 2 as necessary.)
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐6 Page 2 of X, Form Date: March 15, 2016
(Page reserved for continuation of description of general strategy for structural BMP implementation at the site)
(Continued from page 1)
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐6 Page 3 of X (Copy as many as needed) Form Date: March 15, 2016 Structural BMP Summary Information
(Copy this page as needed to provide information for each individual proposed structural BMP) Structural BMP ID No. BMP‐1
Construction Plan Sheet No.
☐ Type of structural BMP:
☐ Retention by harvest and use (HU‐1)
☒ Retention by infiltration basin (INF‐1)
☐ Retention by bioretention (INF‐2)
☐ Retention by permeable pavement (INF‐3)
☐ Partial retention by biofiltration with partial retention (PR‐1) ☐ Biofiltration (BF‐1)
☐ Biofiltration with Nutrient Sensitive Media Design (BF‐2) ☐ Proprietary Biofiltration (BF‐3) meeting all requirements of Appendix F ☐ Flow‐thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below)
☒ Flow‐thru treatment control included as pre‐treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below)
☐ Flow‐thru treatment control with alternative compliance (provide BMP type/description in discussion section below)
☒ Detention pond or vault for hydromodification management ☒ Other (describe in discussion section below)
Purpose:
☐ Pollutant control only
☐ Hydromodification control only
☒ Combined pollutant control and hydromodification control ☐ Pre‐treatment/forebay for another structural BMP
☒ Other (describe in discussion section below)
Who will certify construction of this BMP?
Provide name and contact information for the
party responsible to sign BMP verification forms if
required by the [City Engineer] (See Section 1.12 of
the BMP Design Manual)
Dr. Luis A. Parra
2442 Second Avenue
REC Consultants, Inc.
(619) 232‐9200
Who will be the final owner of this BMP? Pico Investments 7, LLC.
Who will maintain this BMP into perpetuity? Property Owner (Pico Investments 7, LLC.) What is the funding mechanism for maintenance? HOA
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I‐6 Page 4 of X (Copy as many as needed) , Form Date: March 15, 2016 Structural BMP ID No.
Construction Plan Sheet No.
Discussion (as needed):
The proposed underground infiltration BMP vault is a multiple purpose treatment facility – water quality (DCV), HMP and peak flow Q100 flow mitigation is provided by the vault system. Upstream of the vault is a pre‐treatment hydrodynamic separator unit to provide trash & debris screening prior to draining to the infiltration BMP.
The pre‐treatment hydrodynamic separator has no water quality benefit per the current BMP design manual standard and is only present to capture trash/debris/sediment to pre‐screen for the infiltration BMP.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
ATTACHMENT 1
BACKUP FOR PDP POLLUTANT CONTROL BMPS
This is the cover sheet for Attachment 1.
Indicate which Items are Included behind this cover sheet:
Attachment
Sequence
Contents Checklist
Attachment 1a DMA Exhibit (Required)
See DMA Exhibit Checklist on the back of
this Attachment cover sheet.
☒ Included
Attachment 1b Tabular Summary of DMAs Showing DMA
ID matching DMA Exhibit, DMA Area, and
DMA Type (Required)*
*Provide table in this Attachment OR on
DMA Exhibit in Attachment 1a
☒ Included on DMA Exhibit in
Attachment 1a
☐ Included as Attachment 1b, separate
from DMA Exhibit
Attachment 1c Form I‐7, Harvest and Use Feasibility
Screening Checklist (Required unless the
entire project will use infiltration BMPs)
Refer to Appendix B.3‐1 of the BMP
Design Manual to complete Form I‐7.
☒ Included
☐ Not included because the entire
project will use infiltration BMPs
Attachment 1d Form I‐8, Categorization of Infiltration
Feasibility Condition (Required unless the
project will use harvest and use BMPs)
Refer to Appendices C and D of the BMP
Design Manual to complete Form I‐8.
☒ Included
☐ Not included because the entire
project will use harvest and use BMPs
Attachment 1e Pollutant Control BMP Design
Worksheets / Calculations (Required)
Refer to Appendices B and E of the BMP
Design Manual for structural pollutant
control BMP design guidelines
☒ Included
1 DMA/BMP PLAN - PROPOSED
PICO PLACE
236-244 SAN MARCOS PICO AVENUE
SAN MARCOS, CA 92069
1. a. b. 10
c. d.
2. City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Use this checklist to ensure the required information has been included on the DMA Exhibit:
The DMA Exhibit must identify:
☒ Underlying hydrologic soil group
☒ Approximate depth to groundwater
☒ Existing natural hydrologic features (watercourses, seeps, springs, wetlands) ☒ Critical coarse sediment yield areas to be protected
☒ Existing topography and impervious areas
☒ Existing and proposed site drainage network and connections to drainage offsite ☒ Proposed demolition
☒ Proposed grading
☒ Proposed impervious features
☒ Proposed design features and surface treatments used to minimize imperviousness ☒ Drainage management area (DMA) boundaries, DMA ID numbers, and DMA areas (square footage or acreage), and DMA type (i.e., drains to BMP, self‐retaining, or self‐mitigating) ☒ Potential pollutant source areas and corresponding required source controls (see Chapter 4, Appendix E.1, and Form I‐3B)
☒ Structural BMPs (identify location, type of BMP, and size/detail) City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Harvest and Use Feasibility Checklist Form I-7
1. Is there a demand for harvested water (check all that apply) at the project site that is reliably present during the wet season?
Toilet and urinal flushing
Landscape irrigation
Other:
2. If there is a demand; estimate the anticipated average wet season demand over a period of 36 hours.
Guidance for planning level demand calculations for toilet/urinal flushing and landscape irrigation is provided in Section B.3.2.
Toilet and urinal flushing demand: ቀ ଽ.ଷ
௦ିௗ௬ቁቀ ଵ௧య
.ସ଼ቁቂሺ16 ܷ݊݅ݏݐሻ ቀ
ସ ௦
௨ௗቁቃ ሺ1.5݀ܽݕሻ ൌ 119݂ݐଷ
Irrigation demand: ቀ ଵସ
ିଵ.ହௗ௬ቁቀ ଵ௧య
.ସ଼ቁ ሺ1.5݀ܽݕሻሺ0.17 ܽܿݎ݁ሻ ൌ 50݂ݐଷ
Total: 169 cubic-feet
3. Calculate the DCV using worksheet B-2.1.
1,148 cubic-feet
3a. Is the 36-hour demand
greater than or equal to the
DCV?
Yes / No
3b. Is the 36-hour demand greater
than 0.25DCV but less than the full
DCV?
Yes / No
3c. Is the 36-hour demand less
than 0.25DCV?
Yes
Harvest and use appears to be
feasible. Conduct more detailed
evaluation and sizing calculations
to confirm that
DCV can be used at an adequate
rate to meet drawdown criteria.
Harvest and use may be feasible.
Conduct more detailed evaluation and
sizing calculations to determine
feasibility. Harvest and use may only be
able to be used for a portion of the site,
or (optionally) the storage may need to
be upsized to meet long term capture
targets while draining in
longer than 36 hours.
Harvest and use is considered to
be infeasible.
169 ൏ 1,148(0.25)
169 ൏ 287
Is harvest and use feasible based on further evaluation? Yes, refer to Appendix E to select and size harvest and use BMPs.
No, select alternate BMPs.
Note: All rainwater harvest and use must comply with the California Plumbing Code (Sections 1702.9.3, 1702.9.4, etc.).
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
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City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Categorization of Infiltration Feasibility Condition Form I-8 Part 1 - Full Infiltration Feasibility Screening Criteria Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences that cannot be reasonably mitigated?
Note that it is not necessary to investigate each and every criterion in the worksheet if infiltration is precluded.
Instead a letter of justification from a geotechnical professional familiar with the local conditions substantiating any geotechnical issues will be required.
Criteria Screening Question Yes No
1 Is the estimated reliable infiltration rate below proposed facility locations greater than 0.5 inches per hour? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D.
Provide basis:
Onsite percolation tests indicate soils have a measured infiltration rate of 3 in/hr at test boring location P‐1 which is within the vicinity of the proposed infiltration BMP.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability.
Please refer to the DMA Exhibit and BMP calculations included under SWQMP Attachment 1. Additional soils data is included in the Geotechnical Investigation Proposed Multi‐Family Residential Development 236 and 244 Pico Avenue prepared by Global Geo‐Engineering, Inc. (08/31/22). 2 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2.
Provide basis:
Yes – as such an infiltration BMP is being used on the project site.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability.
Per the attached Geotechnical Study, proposed Infiltration will not impact soil stability or utilities in project area.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I-8 Page 2 of 4
Criteria Screening Question Yes No
3 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of groundwater contamination (shallow water table, storm water pollutants or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3.
Provide basis:
Yes – as such an infiltration BMP is being used on the project site.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability.
No nearby groundwater wells were found to be listed during review of California department of water resources website and per Fig. C3, Appendix 3 of BMP Manual historic Ground water is more than 15 feet below ground.
4 Can infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as change of seasonality of ephemeral streams or increased discharge of contaminated groundwater to surface waters? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3.
Provide basis:
Yes – as such an infiltration BMP is being used on the project site.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability.
Proposed infiltration will not impact seasonality of ephemeral streams or increased discharge of contaminated ground water to surface water.
Part 1
Result*
If all answers to rows 1 - 4 are “Yes” a full infiltration design is potentially feasible. The feasibility screening category is Full Infiltration
If any answer from row 1-4 is “No”, infiltration may be possible to some extent but would not generally be feasible or desirable to achieve a “full infiltration” design.
Proceed to Part 2
Yes
No
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I-8 Page 3 of 4
Part 2 – Partial Infiltration vs. No Infiltration Feasibility Screening Criteria Would infiltration of water in any appreciable amount be physically feasible without any negative consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
5 Do soil and geologic conditions allow for infiltration in any appreciable rate or volume? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D.
Provide basis:
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability.
6 Can Infiltration in any appreciable quantity be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2.
Provide basis:
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability.
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: May 12, 2017
Form I-8 Page 4 of 4
Criteria Screening Question Yes No
7 Can Infiltration in any appreciable quantity be allowed without posing significant risk for groundwater related concerns (shallow water table, storm water pollutants or other factors)? The response to this Screening Question shall be based on a
comprehensive evaluation of the factors presented in Appendix C.3.
Provide basis:
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability.
8 Can infiltration be allowed without violating downstream water rights? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3.
Provide basis:
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Part 2
Result*
If all answers from row 1-4 are yes then partial infiltration design is potentially feasible.
The feasibility screening category is Partial Infiltration.
If any answer from row 5-8 is no, then infiltration of any volume is considered to be infeasible within the drainage area. The feasibility screening category is No Infiltration.
Yes
No
3 Corporate Park, Suite 270, Irvine, California 92606
Office (949) 221-0900 Fax (949) 221-0091
Email: [email protected]
August 31, 2022
Project 9421-04
DMS Consultants, Inc.
12377 Lewis Street, Suite 203
Garden Grove, California 92840
Attention: Mr. Surender Dewan, P. E.
President
Subject: Geotechnical Investigation
Proposed Multi-Family Residential Development
236 and 244 Pico Avenue
San Marcos, California
References: See Appendix A
Dear Mr. Dewan:
1. INTRODUCTION
a) In accordance with your request, we have conducted a geotechnical investigation for the proposed residential development located in San Marcos, California. b) We understand that the proposed development will consist of the construction of four 3-story, multi-family residential structures, each unit approximately 1,170- squarefoot, with related parking/driveway areas on a 0.67-acre parcel of land. In addition, an infiltration system is planned to be installed for potential stormwater runoff.
c) Grading and structural plans are not available at present. We are assuming that the existing grades will remain unchanged. We anticipate the loads from the proposed structures will not exceed 3 kip/ft for the continuous footings and 50 kips for the column footings.
2. SCOPE
The scope of services we provided were as follows:
a) Preliminary planning and evaluations, and review of geotechnical reports related to the project site and nearby surrounding area (See References – Appendix A); GLOBAL GEO-ENGINEERING, INC.
DMS Consultants, Inc.
August 31, 2022
Project 9421-04