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Project Specific Water Quality Management Plan
A Template for Projects located within theSanta Ana Watershed Region of Riverside County Project Title: Sunset Crossings - Tract No. 38443
Development No: Tract No. 38443
Design Review/Case No: LWQ22-0029
Original Date Prepared: 5/19/22
Revision Date(s): 4/11/23
Prepared for Compliance with
Regional Board Order No. R8-2010-0033
Contact Information:
Prepared for:
Highpointe, LLC
560 Technology, Suite 100
Irvine, CA 92618
Prepared by:
Dillon Strand
Civil Engineer
951-280-3311
Proactive Engineering Consultants
200 S Main St #300
Corona, CA 92882
Preliminary
Final
3/18/2024
LWQ24-0008
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A Brief Introduction
This Project-Specific WQMP Template for the Santa Ana Region has been prepared to help guide you in documenting compliance for your project. Because this document has been designed to specifically document compliance, you will need to utilize the WQMP Guidance Document as your “how-to” manual to help guide you through this process. Both the Template and Guidance Document go hand-in-hand, and will help facilitate a well prepared Project-Specific WQMP. Below is a flowchart for the layout of this Template that will provide the steps required to document compliance.
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OWNER’S CERTIFICATION
This Project-Specific Water Quality Management Plan (WQMP) has been prepared for Highpointe Communities by Proactive Engineering Consultants, Inc. for the Sunset Crossings - Tract No. 38443 project.
This WQMP is intended to comply with the requirements of The City of Moreno Valley for Ordinance 827 § 2.1, 2011 which includes the requirement for the preparation and implementation of a Project-Specific WQMP.
The undersigned, while owning the property/project described in the preceding paragraph, shall be responsible for the implementation and funding of this WQMP and will ensure that this WQMP is amended as appropriate to reflect up-to-date conditions on the site. In addition, the property owner accepts responsibility for interim operation and maintenance of Stormwater BMPs until such time as this responsibility is formally transferred to a subsequent owner. This WQMP will be reviewed with the facility operator, facility supervisors, employees, tenants, maintenance and service contractors, or any other party (or parties) having responsibility for implementing portions of this WQMP. At least one copy of this WQMP will be maintained at the project site or project office in perpetuity. The undersigned is authorized to certify and to approve implementation of this WQMP. The undersigned is aware that implementation of this WQMP is enforceable under City of Lake Elsinore Water Quality Ordinance (Municipal Code Section Chapter 8.10). "I, the undersigned, certify under penalty of law that the provisions of this WQMP have been reviewed and accepted and that the WQMP will be transferred to future successors in interest." Owner’s Signature Date
Owner’s Printed Name Owner’s Title/Position
PREPARER’S CERTIFICATION
“The selection, sizing and design of stormwater treatment and other stormwater quality and quantity control measures in this plan meet the requirements of Regional Water Quality Control Board Order No. R8-2010-0033 and any subsequent amendments thereto.”
Preparer’s Signature Date
Preparer’s Printed Name Preparer’s Title/Position
Preparer’s Licensure:
3/18/2024
Project Manager
Dillon Strand
Timothy D. England COO
DocuSign Envelope ID: B0BEAD99-359C-4E95-A81F-5CB2241641F3 3/18/2024
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Table of Contents
Section A: Project and Site Information ................................................................................................... 6 A.1 Maps and Site Plans ....................................................................................................................... 6 A.2 Identify Receiving Waters .............................................................................................................. 7 A.3 Additional Permits/Approvals required for the Project:.................................................................. 8 Section B: Optimize Site Utilization (LID Principles) .................................................................................. 9 Section C: Delineate Drainage Management Areas (DMAs) .................................................................... 11 Section D: Implement LID BMPs ............................................................................................................ 13 D.1 Infiltration Applicability ............................................................................................................... 13 D.2 Harvest and Use Assessment ....................................................................................................... 14 D.3 Bioretention and Biotreatment Assessment................................................................................. 16 D.4 Feasibility Assessment Summaries ............................................................................................... 17 D.5 LID BMP Sizing ............................................................................................................................. 17 Section E: Alternative Compliance (LID Waiver Program) ....................................................................... 19 E.1 Identify Pollutants of Concern ...................................................................................................... 20 E.2 Stormwater Credits ...................................................................................................................... 21 E.3 Sizing Criteria ............................................................................................................................... 21 E.4 Treatment Control BMP Selection ................................................................................................ 22 Section F: Hydromodification ................................................................................................................ 23 F.1 Hydrologic Conditions of Concern (HCOC) Analysis ....................................................................... 23 F.2 HCOC Mitigation .......................................................................................................................... 24 Section G: Source Control BMPs ............................................................................................................ 25 Section H: Construction Plan Checklist ................................................................................................... 28 Section I: Operation, Maintenance and Funding .................................................................................... 29 - 5 -
List of Tables
Table A.1 Identification of Receiving Waters ............................................................................................ 7 Table A.2 Other Applicable Permits ......................................................................................................... 8 Table C.1 DMA Classifications ................................................................................................................ 11 Table C.2 Type ‘A’, Self-Treating Areas ................................................................................................... 11 Table C.3 Type ‘B’, Self-Retaining Areas ................................................................................................. 11 Table C.4 Type ‘C’, Areas that Drain to Self-Retaining Areas ................................................................... 12 Table C.5 Type ‘D’, Areas Draining to BMPs ........................................................................................... 12 Table D.1 Infiltration Feasibility ............................................................................................................. 13 Table D.2 LID Prioritization Summary Matrix.......................................................................................... 17 Table D.3 DCV Calculations for LID BMPs ............................................................................................... 18 Table E.1 Potential Pollutants by Land Use Type .................................................................................... 20 Table E.2 Water Quality Credits ............................................................................................................. 21 Table E.3 Treatment Control BMP Sizing ................................................................................................ 21 Table E.4 Treatment Control BMP Selection .......................................................................................... 22 Table F.1 Hydrologic Conditions of Concern Summary ........................................................................... 23 Table G.1 Permanent and Operational Source Control Measures ........................................................... 25 Table H.1 Construction Plan Cross-reference ......................................................................................... 28 List of Appendices
Appendix 1: Maps and Site Plans ........................................................................................................... 30 Appendix 2: Construction Plans ............................................................................................................. 31 Appendix 3: Soils Information ................................................................................................................ 32 Appendix 4: Historical Site Conditions ................................................................................................... 33 Appendix 5: LID Infeasibility................................................................................................................... 34 Appendix 6: BMP Design Details ............................................................................................................ 35 Appendix 7: Hydromodification ............................................................................................................. 36 Appendix 8: Source Control ................................................................................................................... 37 Appendix 9: O&M .................................................................................................................................. 38 Appendix 10: Educational Materials..................................................................................................... - 6 - - 6 -
Section A: Project and Site Information
PROJECT INFORMATION
Type of Project: Residential
Planning Area: R3
Community Name: TBD
Development Name: TBD
PROJECT LOCATION
Latitude & Longitude (DMS): 33°55'19.0" N 117°11'14.0"W Project Watershed and Sub-Watershed: Santa Ana Watershed APN(s): 488-210-006, 488-210-020
Map Book and Page No.: Map Book 11, Page 10
PROJECT CHARACTERISTICS
Proposed or Potential Land Use(s) Detached Residential
Proposed or Potential SIC Code(s) 1521
Area of Impervious Project Footprint (SF) 1,255,051
Total Area of proposed Impervious Surfaces within the Project Limits (SF)/or Replacement 815,783 Does the project consist of offsite road improvements? Y N Does the project propose to construct unpaved roads? Y N Is the project part of a larger common plan of development (phased project)? Y N
EXISTING SITE CHARACTERISTICS
Total area of existing Impervious Surfaces within the project limits (SF) 0 Is the project located within any MSHCP Criteria Cell? Y N If so, identify the Cell number: N/A
Are there any natural hydrologic features on the project site? Y N Is a Geotechnical Report attached? Y N
If no Geotech. Report, list the NRCS soils type(s) present on the site (A, B, C and/or D) B What is the Water Quality Design Storm Depth for the project? 0.68 A.1 Maps and Site Plans
When completing your Project-Specific WQMP, include a map of the local vicinity and existing site. In addition, include all grading, drainage, landscape/plant palette and other pertinent construction plans in Appendix 2. At a minimum, your WQMP Site Plan should include the following:
· Drainage Management Areas
· Proposed Structural BMPs
· Drainage Path
· Drainage Infrastructure, Inlets, Overflows
· Source Control BMPs
· Buildings, Roof Lines, Downspouts
· Impervious Surfaces
· Standard Labeling
U s e y o u r d i s c r e t i o n o n w h e t h e r o r no t y o u m a y n e ed t o c r e a t e m u l t i p l e s h e e t s o r c a n a p p r o p r i a t e l y accommodate these features on one or two sheets. Keep in mind that the Co-Permittee plan reviewer must be able to easily analyze your project utilizing this template and its associated site plans and maps. - 7 -
Project Description
The proposed project boundary encompasses approximately 20 acres. The project site is undeveloped land, and the existing land cover consists of natural native grass based on aerial photography.
The proposed development will build 108 single family homes, sidewalks, streets, open space areas, a Detention/Extended Detention Basins, and a storm drain network system to convey offsite and onsite runoff. A proposed onsite storm drain pipe network will convey onsite runoff to the proposed Detention/Extended Detention basins. The proposed Detention/Extended Detention basin will treat and detain runoff, outlet structures will convey treated runoff to the proposed storm drain, LINE H, in Street A.
A.2 Identify Receiving Waters
Using Table A.1 below, list in order of upstream to downstream, the receiving waters that the project s i t e i s t r i b u t a r y t o . C o n t i n u e t o f i l l e a c h r o w w i t h t h e R e c e i v i n g W a t e r ’ s 3 0 3 ( d ) l i s t e d i m p a i r m e n t s ( i f any), designated beneficial uses, and proximity, if any, to a RARE beneficial use. Include a map of the receiving waters in Appendix 1.
Table A.1 Identification of Receiving Waters
Receiving
Waters
EPA Approved 303(d) List
Impairments
Designated
Beneficial Uses
P r o x i m i t y t o R A R E
Beneficial Use
San Jacinto
River Reach 3
N/A A G R , G W R , W I L D , M U N , R E C 1 , R E C 2 ,
WARM, WILD
N o R A R E b e n e f i c i a l u s e
within receiving water
body
san jacinto
river reach 2 Nutrients A G R , G W R , W I L D , M U N , R E C 1 , R E C 2 , WARM
N o R A R E b e n e f i c i a l u s e
within receiving water
body
San Jacinto
River Reach 1 N/A A G R , G W R , W I L D , M U N , R E C 1 , R E C 2 ,
WARM, WILD
N o R A R E b e n e f i c i a l u s e
within receiving water
body
Lake Elsinore
Nutrients Organic Enrichment/Low Dissolved
Oxygen PCBs; Sediment Toxicity Unknown
Toxicity, DDT
REC1, REC2, WARM, WILD
N o R A R E b e n e f i c i a l u s e
within receiving water
body
Temescal Creek
Reach 6 Indicator Bacteria INTERMITTENT - GWR,
REC1, REC2, WARM, WILD
N o R A R E b e n e f i c i a l u s e
within receiving water
body
Temescal Creek
Reach 5 N/A AGR, GWR, REC1, REC2,
WARM, WILD, RARE
19.8 miles
Temescal Creek
Reach 4 N/A AGR, GWR, REC1, REC2,
WARM, WILD, RARE
20.7 miles
Temescal Creek
Reach 3 N/A AGR, IND, GWR, REC1,
REC2, WARM, WILD
N o R A R E b e n e f i c i a l u s e
within receiving water
body
Temescal Creek
Reach 2 N/A AGR, IND, GWR, REC1,
REC2, WARM, WILD
N o R A R E b e n e f i c i a l u s e
within receiving water
body
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Temescal Creek
Reach 1a pH REC2, WARM, WILD
N o R A R E b e n e f i c i a l u s e
within receiving water
body
Temescal Creek
Reach 1b pH REC2, WARM, WILD
N o R A R E b e n e f i c i a l u s e
within receiving water
body
Prado Park
Lake Nutrients, Pathogens, REC1, REC2, COMM, WARM, WILD N o R A R E b e n e f i c i a l u s e
within receiving water
body
Santa Ana River
Reach 3 Copper, Lead, Pathogens A G R , G W R , R E C 1 , R E C 2 , W A R M , W I L D ,
RARE, SPWN
N o R A R E b e n e f i c i a l u s e
within receiving water
body
Santa Ana River
Reach 2 Indicator Bacteria A G R , G W R , R E C 1 , R E C 2 , W A R M , W I L D , RARE, SPWN 44.7 miles
Santa Ana River
Reach 1 N/A REC1, REC2, WARM, WILD
N o R A R E b e n e f i c i a l u s e
within receiving water
body
Lee Lake N/A AGR, IND, GWR, REC1,
REC2, WARM, WILD
N o R A R E b e n e f i c i a l u s e
within receiving water
body
A.3 Additional Permits/Approvals required for the Project:
Table A.2 Other Applicable Permits
Agency Permit Required
State Department of Fish and Game, 1602 Streambed Alteration Agreement Y N State Water Resources Control Board, Clean Water Act (CWA) Section 401 Water Quality Cert. Y N US Army Corps of Engineers, CWA Section 404 Permit Y N US Fish and Wildlife, Endangered Species Act Section 7 Biological Opinion Y N Statewide Construction General Permit Coverage Y N
Statewide Industrial General Permit Coverage Y N
Western Riverside MSHCP Consistency Approval (e.g., JPR, DBESP) Y N Other (please list in the space below as required)
City of Moreno Valley Permits Y N
I f y e s i s a n s w e r e d t o a n y o f t h e q u e s t i o n s a b o v e , t h e C o - P e r m i t t e e m a y r e q u i r e p r o o f o f approval/coverage from those agencies as applicable including documentation of any associated requirements that may affect this Project-Specific WQMP. - 9 -
Section B: Optimize Site Utilization (LID Principles)
Review of the information collected in Section ‘A’ will aid in identifying the principal constraints on site design and selection of LID BMPs as well as opportunities to reduce imperviousness and incorporate LID Principles into the site and landscape design. For example, constraints might include impermeable soils, high groundwater, groundwater pollution or contaminated soils, steep slopes, geotechnical instability, high-intensity land use, heavy pedestrian or vehicular traffic, utility locations or safety concerns. Opportunities might include existing natural areas, low areas, oddly configured or otherwise unbuildable parcels, easements and landscape amenities including open space and buffers (which can double as locations for bioretention BMPs), and differences in elevation (which can provide hydraulic h e a d ) . P r e p a r e a b r i e f n a r r a t i v e f o r e a c h o f t h e s i t e o p t i m i z a t i o n s t r a t e g i e s d e s c r i b e d b e l o w . T h i s narrative will help you as you proceed with your LID design and explain your design decisions to others.
The 2010 Santa Ana MS4 Permit further requires that LID Retention BMPs (Infiltration Only or Harvest and Use) be used unless it can be shown that those BMPs are infeasible. Therefore, it is important that your narrative identify and justify if there are any constraints that would prevent the use of those categories of LID BMPs. Similarly, you should also note opportunities that exist which will be utilized during project design. Upon completion of identifying Constraints and Opportunities, include these on your WQMP Site plan in Appendix 1.
Site Optimization
The following questions are based upon Section 3.2 of the WQMP Guidance Document. Review of the WQMP Guidance Document will help you determine how best to optimize your site and subsequently identify opportunities and/or constraints, and document compliance.
Did you identify and preserve existing drainage patterns? If so, how? If not, why? Existing drainage patterns are preserved. In its current condition, storm water runoff from the site sheet flows south towards Alessandro Boulevard. In the proposed condition, storm water runoff will be routed through a proposed RCP storm drain master plan facility. The proposed RCP storm drain master plan facility will operated by Riverside County Flood Control & Water Conservation District.
Did you identify and protect existing vegetation? If so, how? If not, why? Based on field visits, the vegetation on the site consists of native grass. Grading and site preparation and preservation will be prepared per Geotechnical report.
Did you identify and preserve natural infiltration capacity? If so, how? If not, why? Infiltration capacity has been identified through infiltration tests within the project site. Runoff is routed to pervious surfaces to maximize infiltration capacity within the site.
Did you identify and minimize impervious area? If so, how? If not, why? Impervious areas minimized by providing landscape areas within lots, park/open recreational areas and two extended detention basins.
Did you identify and disperse runoff to adjacent pervious areas? If so, how? If not, why? - 10 -
Runoff from roofs will be diverted to landscape areas through the use of splash blocks, runoff from streets will be conveyed to an extended detention basins. - 11 -
Section C: Delineate Drainage Management Areas
(DMAs)
Utilizing the procedure in Section 3.3 of the WQMP Guidance Document which discusses the methods of delineating and mapping your project site into individual DMAs, complete Table C.1 below to appropriately categorize the types of classification (e.g., Type A, Type B, etc.) per DMA for your project site. Upon completion of this table, this information will then be used to populate and tabulate the corresponding tables for their respective DMA classifications.
Table C.1 DMA Classifications
DMA Name or ID Surface Type(s)1 Area (Sq. Ft.) DMA Type DMA A/1 Mixed Surface Types 1,179,020 Type ‘D’
DMA A/2 Natural (B Soil) 131,002 Type ‘D’
1Reference Table 2-1 in the WQMP Guidance Document to populate this column Table C.2 Type ‘A’, Self-Treating Areas
DMA Name or ID Area (Sq. Ft.) Stabilization Type Irrigation Type (if any) Table C.3 Type ‘B’, Self-Retaining Areas
Self-Retaining Area
T y p e ‘ C ’ D M A s t h a t a r e d r a i n i n g t o t h e S e l f -Retaining Area
DMA
Name/ ID
Post-project
surface type
Area
(square
feet)
Storm
Depth
(inches) DMA Name /
ID
[C] from Table C.4
=
Required Retention Depth
(inches)
[A] [B] [C] [D]
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Table C.4 Type ‘C’, Areas that Drain to Self-Retaining Areas DMA Receiving Self-Retaining DMA
DMA Name/ ID
Area
(square feet)
Post-project
surface type
Runoff
factorProduct
DMA name /ID
Area (square
feet) Ratio
[A] [B] [C] = [A] x [B] [D] [C]/[D]
Table C.5 Type ‘D’, Areas Draining to BMPs
DMA Name or ID BMP Name or ID
DMA A/1 Extended Detention Basin No 1.
Note: More than one drainage management area can drain to a single LID BMP, however, one drainage management area may not drain to more than one BMP. - 13 -
Section D: Implement LID BMPs
D.1 Infiltration Applicability
Is there an approved downstream ‘Highest and Best Use’ for stormwater runoff (see discussion in Chapter 2.4.4 of the WQMP Guidance Document for further details)? Y N If yes has been checked, Infiltration BMPs shall not be used for the site. If no, continue working through t h i s s e c t i o n t o i m p l e m e n t y o u r L I D B M P s . I t i s r e c o m m e n d e d t h a t y o u c o n t a c t y o u r C o - P e r m i t t e e t o verify whether or not your project discharges to an approved downstream ‘Highest and Best Use’ feature.
Geotechnical Report
A Geotechnical Report or Phase I Environmental Site Assessment may be required by the Copermittee to confirm present and past site characteristics that may affect the use of Infiltration BMPs. In addition, the Co-Permittee, at their discretion, may not require a geotechnical report for small projects as described in Chapter 2 of the WQMP Guidance Document. If a geotechnical report has been prepared, include it in Appendix 3. In addition, if a Phase I Environmental Site Assessment has been prepared, include it in Appendix 4.
Is this project classified as a small project consistent with the requirements of Chapter 2 of the WQMP Guidance Document?
Y N
Infiltration Feasibility
T a b l e D . 1 b e l o w i s m e a n t t o p r o v i d e a s i m p l e m e a n s o f a s s e s s i n g w h i c h D M A s o n y o u r s i t e s u p p o r t Infiltration BMPs and is discussed in the WQMP Guidance Document in Chapter 2.4.5. Check the appropriate box for each question and then list affected DMAs as applicable. If additional space is needed, add a row below the corresponding answer.
Table D.1 Infiltration Feasibility
Does the project site… YES NO
…have any DMAs wi th a seasonal high groundwater mark shallower than 10 feet? X If Yes, list affected DMAs:
…have any DMAs located within 100 feet of a water supply well? X If Yes, list affected DMAs:
…have any areas identified by the geotechnical report as posing a public safety risk where infiltration of stormwater could have a negative impact?
X
If Yes, list affected DMAs:
…have measured in -situ infiltration rates of less than 1.6 inches / hour? X If Yes, list affected DMAs: DMA A-2
…have significant cut and/or fill conditions that would preclude in-situ testing of infiltration rates at the final infiltration surface?
X
If Yes, list affected DMAs:
…geotechnical report identify other site-specific factors that would preclude effective and safe infiltration? X Describe here:
If you answered “Yes” to any of the questions above for any DMA, Infiltration BMPs should not be used for those DMAs and you should proceed to the assessment for Harvest and Use below. - 14 -
D.2 Harvest and Use Assessment
Please check what applies:
☐ Reclaimed water will be used for the non-potable water demands for the project. ☐Downstream water rights may be impacted by Harvest and Use as approved by the Regional Board (verify with the Copermittee).
☐The Design Capture Volume will be addressed using Infiltration Only BMPs. In such a case, Harvest and Use BMPs are still encouraged, but it would not be required if the Design Capture Volume will be infiltrated or evapotranspired.
If any of the above boxes have been checked, Harvest and Use BMPs need not be assessed for the site. If neither of the above criteria applies, follow the steps below to assess the feasibility of irrigation use, toilet use and other non-potable uses (e.g., industrial use).
Irrigation Use Feasibility
Complete the following steps to determine the feasibility of harvesting stormwater runoff for Irrigation Use BMPs on your site:
Step 1: Identify the total area of irrigated landscape on the site, and the type of landscaping used.
Total Area of Irrigated Landscape: 1.95 Acres
Type of Landscaping (Conservation Design or Active Turf) : Conservation Design consisting of native vegetation.
Step 2: Identify the planned total of all impervious areas on the proposed project from which runoff might be feasibly captured and stored for irrigation use. Depending on the configuration of b u i l d i n g s a n d o t h e r i m p e r v i o u s a r e a s o n t h e s i t e , y o u m a y c o n s i d e r t h e s i t e a s a w h o l e , o r parts of the site, to evaluate reasonable scenarios for capturing and storing runoff and directing the stored runoff to the potential use(s) identified in Step 1 above.
Total Area of Impervious Surfaces: 18.3 Acres
S t e p 3 : C r o s s r e f e r e n c e t h e D e s i g n S t o r m d e p t h f o r t h e p r o j e c t s i t e ( s e e E x h i b i t A o f t h e W Q M P Guidance Document) with the left column of Table 2-3 in Chapter 2 to determine the minimum area of Effective Irrigated Area per Tributary Impervious Area (EIATIA).
Enter your EIATIA factor: 1.19 (By interpolating values in Table 2-3) Step 4: Multiply the unit value obtained from Step 3 by the total of impervious areas from Step 2 to develop the minimum irrigated area that would be required.
Minimum required irrigated area: 21.08 Acres
Step 5: Determine if harvesting stormwater runoff for irrigation use is feasible for the project by comparing the total area of irrigated landscape (Step 1) to the minimum required irrigated area (Step 4).
Minimum required irrigated area (Step 4) Available Irrigated Landscape (Step 1)
21.08 Acres 2.81 Acres
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Toilet Use Feasibility
Complete the following steps to determine the feasibility of harvesting stormwater runoff for toilet flushing uses on your site:
Step 1: Identify the projected total number of daily toilet users during the wet season, and account for any periodic shut downs or other lapses in occupancy:
Projected Number of Daily Toilet Users: 670 (5 users per home dwelling unit) Project Type: Residential
Step 2: Identify the planned total of all impervious areas on the proposed project from which runoff might be feasibly captured and stored for toilet use. Depending on the configuration of b u i l d i n g s a n d o t h e r i m p e r v i o u s a r e a s o n t h e s i t e , y o u m a y c o n s i d e r t h e s i t e a s a w h o l e , o r parts of the site, to evaluate reasonable scenarios for capturing and storing runoff and directing the stored runoff to the potential use(s) identified in Step 1 above.
Total Area of Impervious Surfaces: 18.3 Acres
Step 3: Enter the Design Storm depth for the project site (see Exhibit A) into the left column of Table 2-1 in Chapter 2 to determine the minimum number or toilet users per tributary impervious acre (TUTIA).
Enter your TUTIA factor: 112 tu/ac (By interpolating Values) Step 4: Multiply the unit value obtained from Step 3 by the total of impervious areas from Step 2 to develop the minimum number of toilet users that would be required.
Minimum number of toilet users: 2,050
Step 5: Determine if harvesting stormwater runoff for toilet flushing use is feasible for the project by comparing the Number of Daily Toilet Users (Step 1) to the minimum required number of toilet users (Step 4).
Minimum required Toilet Users (Step 4) Projected number of toilet users (Step 1) 2,050 670
Other Non-Potable Use Feasibility
Are there other non-potable uses for stormwater runoff on the site (e.g. industrial use)? See Chapter 2 of the Guidance for further information. If yes, describe below. If no, write N/A.
N/A
Step 1: Identify the projected average daily non-potable demand, in gallons per day, during the wet season and accounting for any periodic shut downs or other lapses in occupancy or operation.
Average Daily Demand: N/A
Step 2: Identify the planned total of all impervious areas on the proposed project from which runoff might be feasibly captured and stored for the identified non-potable use. Depending on the configuration of buildings and other impervious areas on the site, you may consider the site as a whole, or parts of the site, to evaluate reasonable scenarios for capturing and storing runoff and directing the stored runoff to the potential use(s) identified in Step 1 above. - 16 -
Total Area of Impervious Surfaces: N/A
Step 3: Enter the Design Storm depth for the project site (see Exhibit A) into the left column of Table 2-3 in Chapter 2 to determine the minimum demand for non-potable uses per tributary impervious acre.
Enter the factor from Table 2-3: N/A
Step 4: Multiply the unit value obtained from Step 4 by the total of impervious areas from Step 3 to develop the minimum number of gallons per day of non-potable use that would be required.
Minimum required use: N/A
Step 5: Determine if harvesting stormwater runoff for other non-potable use is feasible for the project by comparing the Number of Daily Toilet Users (Step 1) to the minimum required number of toilet users (Step 4).
Minimum required non-potable use (Step 4) Projected average daily use (Step 1)
N/A N/A
If Irrigation, Toilet and Other Use feasibility anticipated demands are less than the applicable minimum values, Harvest and Use BMPs are not required and you should proceed to utilize LID Bioretention and Biotreatment, unless a site-specific analysis has been completed that demonstrates technical infeasibility as noted in D.3 below.
D.3 Bioretention and Biotreatment Assessment
Other LID Bioretention and Biotreatment BMPs as described in Chapter 2.4.7 of the WQMP Guidance Document are feasible on nearly all development sites with sufficient advance planning.
Select one of the following:
X LID Bioretention/Biotreatment BMPs will be used for some or all DMAs of the project as noted below in Section D.4 (note the requirements of Section 3.4.2 in the WQMP Guidance Document).
☐ A site-specific analysis demonstrating the technical infeasibility of all LID BMPs has been performed and is included in Appendix 5. If you plan to submit an analysis demonstrating the technical infeasibility of LID BMPs, request a pre-submittal meeting with the Copermittee to discuss this option. Proceed to Section E to document your alternative compliance measures. - 17 -
D.4 Feasibility Assessment Summaries
From the Infiltration, Harvest and Use, Bioretention and Biotreatment Sections above, complete Table D.2 below to summarize which LID BMPs are technically feasible, and which are not, based upon the established hierarchy.
Table D.2 LID Prioritization Summary Matrix
DMA
Name/ID
LID BMP Hierarchy No LID
(Alternative
Compliance)1. Infiltration 2. Harvest and use 3. Bioretention 4. Biotreatment A
For those DMAs where LID BMPs are not feasible, provide a brief narrative below summarizing why they are not feasible, include your technical infeasibility criteria in Appendix 5, and proceed to Section E below to document Alternative Compliance measures for those DMAs. Recall that each proposed DMA must pass through the LID BMP hierarchy before alternative compliance measures may be considered.
The infiltration rate throughout the project site is poor. The infiltration rates after applying a safety factor of 3.0 are 0.4 inch/hr (1.29 in/hr unfactored) for DMA A which is well below than 1.6 in/hr threshold. Per the soils report, based on the fines content for the site may significantly affect long-term field performance of infiltration BMP’s even between appropriate maintenance cycles.
See attached soils report in Appendix 3.
A summary of infiltration feasibility has been provided by Leighton, dated November 23, 2022. This project will require removal and compaction of the first 12' to 14' of soil, which will further impact infiltration capacity. Therefore, it is the soils engineer direction that bioretention or onsite infiltration not be used within the project limits. See summary of Infiltration memo provided in Appendix 3.
Based on the LID BMP Prioritization and Feasibility Flow Chart, an Extended Detention basins was selected as an appropriate treatment BMPs for DMA A.
D.5 LID BMP Sizing
Each LID BMP must be designed to ensure that the Design Capture Volume will be addressed by the selected BMPs. First, calculate the Design Capture Volume for each LID BMP using the V BMP worksheet in Appendix F of the LID BMP Design Handbook. Second , design t he LID BMP t o meet t he required V BMP using a method approved by the Copermittee. U t i l i z e t h e w o r k s h e e t s f o u n d i n t h e L I D B M P D e s i g n Handbook or c onsult wit h your Copermit t ee t o assist you in c orrec t ly sizing your LID BMPs . Comp let e Table D.3 below to document the Design Capture Volume and the Proposed Volume for each LID BMP.
Provide the completed design procedure sheets for each LID BMP in Appendix 6. You may add additional rows to the table below as needed.
- 18 -
Table D.3 DCV Calculations for LID BMPs
DMA
Type/ID
DMA Area
(square
feet)
Post-
Project
Surface
Type
Effective
Impervious
Fraction, If
DMA
Runoff
Factor
DMA
A r e a s x
Runoff
Factor
Extended Detention Basin 1
[A] [B] [C] [A] x [C]
Design
Storm
Depth
(in)
Design Capture
Volume, VBMP
(cubic feet)
Proposed
Volume
on Plans
(cubic
feet)
A-1 1,179,020 Mixed
Surface
Types
0.65 0.45 529,590
A-2 131,002 Open
Space
0.15 0.14 18,529
1,310,022 548,119 0.68 31,060 34,422
BASIN NO 1
EXTENDED DETENTION BASIN SIZING CALCULATIONS
STAGE VS. VOLUME
ELEVATION
DETENTION
BASIN DEPTH
(ft)
CONTOUR
AREA (sf)
AVG.
AREA (sf)
VOLUME (cu.
ft.)
TOTAL
VOLUME (cu -
ft.)
1593.00 0.00 5,614 0 0 0
1593.33 0.33 5,936 5,775 1,925 1,925
1593.67 0.67 6,270 6,103 2,034 3,959
1594.00 1.00 6,651 6,461 2,153 6,113
1594.33 1.33 6,997 6,824 2,275 8,387
1594.67 1.67 7,350 7,174 2,391 10,779
1595.00 2.00 7,743 7,547 2,515 13,294
1595.33 2.33 8,098 7,921 2,640 15,934
1595.67 2.67 8,458 8,278 2,759 18,694
1596.00 3.00 8,892 8,675 2,892 21,585
1596.33 3.33 9,264 9,078 3,026 24,611
1596.67 3.67 9,461 9,363 3,121 27,732
1597.00 4.00 10,096 9,779 3,259 30,992
1597.33 4.33 10,486 10,291 3,430 34,422
1597.67 4.67 10,882 10,684 3,561 37,983
1598.00 5.00 11,355 11,119 3,706 41,689
1598.33 5.33 11,767.00 11,561 3,815 45,505
- 19 -
Section E: Alternative Compliance (LID Waiver Program)
LID BMPs are expected to be feasible on virtually all projects. Where LID BMPs have been demonstrated to be infeasible as documented in Section D, other Treatment Control BMPs must be used (subject to LID waiver approval by the Copermittee). Check one of the following Boxes:
X LID Principles and LID BMPs have been incorporated into the site design to fully address all Drainage Management Areas. No alternative compliance measures are required for this project and thus this Section is not required to be completed.
- Or -
☐ T h e f o l l o w i n g D r a i n a g e M a n a g e m e n t A r e a s a r e u n a b l e t o b e a d d r e s s e d u s i n g L I D B M P s . A site-specific analysis demonstrating technical infeasibility of LID BMPs has been approved by the Co-Permittee and included in Appendix 5. Additionally, no downstream regional and/or sub- regional LID BMPs exist or are available for use by the project. The following alternative compliance measures on the following pages are being implemented to ensure that any pollutant loads expected to be discharged by not incorporating LID BMPs, are fully mitigated. - 20 -
E.1 Identify Pollutants of Concern
Utilizing Table A.1 from Section A above which noted your project’s receiving waters and their associated EPA approved 303(d) listed impairments, cross reference this information with that of your selected Priority Development Project Category in Table E.1 below. If the identified General Pollutant Categories are the same as those listed for your receiving waters, then these will be your Pollutants of Conc ern and t he appropriat e box or boxes will be c h ec ked on t he last row. T he purpose of t his is t o document compliance and to help you appropriately plan for mitigating your Pollutants of Concern in lieu of implementing LID BMPs.
Table E.1 Potential Pollutants by Land Use Type
Priority Development
Project Categories and/or
Project Features (check those
that apply)
General Pollutant Categories
Bacterial
Indicators Metals Nutrients Pesticides
Toxic
Organic
Compounds
Sediments Trash &
Debris
O i l &
Grease
Detached Residential
Development P N P P N P P P
Attached Residential
Development P N P P N P P P (2)
Commercial/Industrial
Development P(3) P P (1) P(1) P(5) P(1) P P
Automotive Repair
Shops N P N N P (4, 5) N P P
Restaurants
(>5,000 ft2) P N N N N N P P
Hillside Development
(>5,000 ft2) P N P P N P P P
Parking Lots
(>5,000 ft2) P(6) P P (1) P(1) P(4) P(1) P P
Retail Gasoline Outlets N P N N P N P P
Project Priority Pollutant(s)
of Concern
P = Potential
N = Not Potential
(1) A potential Pollutant if non-native landscaping exists or is proposed onsite; otherwise not expected (2) A potential Pollutant if the project includes uncovered parking areas; otherwise not expected (3) A potential Pollutant is land use involving animal waste (4) Specifically petroleum hydrocarbons
(5) Specifically solvents
(6) Bacterial indicators are routinely detected in pavement runoff - 21 -
E.2 Stormwater Credits
Projects that cannot implement LID BMPs but nevertheless implement smart growth principles are potentially eligible for Stormwater Credits. Utilize Table 3-8 within the WQMP Guidance Document to identify your Project Category and its associated Water Quality Credit. If not applicable, write N/A.
Table E.2 Water Quality Credits
Qualifying Project Categories Credit Percentage2
N/A N/A
Total Credit Percentage1
1Cannot Exceed 50%
2Obtain corresponding data from Table 3-8 in the WQMP Guidance Document E.3 Sizing Criteria
A f t e r y o u a p p r o p r i a t e l y c o n s i d e r e d S t o r m w a t e r C r e d i t s f o r y o u r p r o j e c t , u t i l i z e T a b l e E . 3 b e l o w t o appropriately size them to the DCV, or Design Flow Rate, as applicable. Please reference Chapter 3.5.2 of the WQMP Guidance Document for further information.
Table E.3 Treatment Control BMP Sizing
DMA
Type/ID
DMA
Area
(square
feet)
Post-
Project
Surface
Type
Effective
Impervious
Fraction, If
DMA
Runoff
Factor
DMA
A r e a x
Runoff
Factor
Enter BMP Name / Identifier Here
[A] [B] [C] [A] x [C]
N/A N/A N/A N/A N/A N/A
Design
Storm
Depth
(in)
Minimum
Design
Capture
Volume or
Design Flow
Rate (cubic
feet or cfs)
Total Storm
Water
Credit %
Reduction
Proposed
Volume
or Flow
on Plans
(cubic
feet or
cfs)
N/A N/A N/A N/A N/A N/A
[B], [C] is obtained as described in Section 2.3.1 from the WQMP Guidance Document [E] is obtained from Exhibit A in the WQMP Guidance Document [G] is for Flow-Based Treatment Control BMPs [G] = 43,560, for Volume-Based Control Treatment BMPs, [G] = 12 [H] is from the Total Credit Percentage as Calculated from Table E.2 above [I] as obtained from a design procedure sheet from the BMP manufacturer and should be included in Appendix 6 - 22 -
E.4 Treatment Control BMP Selection
Treatment Control BMPs typically provide proprietary treatment mechanisms to treat potential pollutants in runoff, but do not sustain significant biological processes. Treatment Control BMPs must have a removal efficiency of a medium or high effectiveness as quantified below:
· High: equal to or greater than 80% removal efficiency · Medium: between 40% and 80% removal efficiency
Such removal efficiency documentation (e.g., studies, reports, etc.) as further discussed in Chapter 3.5.2 of the WQMP Guidance Document, must be included in Appendix 6. In addition, ensure that proposed Treatment Control BMPs are properly identified on the WQMP Site Plan in Appendix 1.
Table E.4 Treatment Control BMP Selection
Selected Treatment Control BMP
Name or ID1
Priority Pollutant(s) of
Concern to Mitigate2
Removal Efficiency
Percentage3
N/A N/A N/A
1 Treatment Control BMPs must not be constructed within Receiving Waters. In addition, a proposed Treatment Control BMP may be listed more than once if they possess more than one qualifying pollutant removal efficiency. 2 Cross Reference Table E.1 above to populate this column. 3 As documented in a Co-Permittee Approved Study and provided in Appendix 6. - 23 -
Section F: Hydromodification
F.1 Hydrologic Conditions of Concern (HCOC) Analysis
Once you have determined that the LID design is adequate to address water quality requirements, you w i l l n e e d t o a s s e s s i f t h e p r o p o s e d L I D D e s i g n m a y s t i l l c r e a t e a H C O C . R e v i e w C h a p t e r s 2 a n d 3 (including Figure 3-7) of the WQMP Guidance Document to determine if your project must mitigate for Hydromodification impacts. If your project meets one of the following criteria which will be indicated by the check boxes below, you do not need to address Hydromodification at this time. However, if the project does not qualify for Exemptions 1, 2 or 3, then additional measures must be added to the design to comply with HCOC criteria. This is discussed in further detail below in Section F.2.
HCOC EXEMPTION 1: The Priority Development Project disturbs less than one acre. The Copermittee has the discretion to require a Project-Specific WQMP to address HCOCs on projects less than one acre on a case by case basis. The disturbed area calculation should include all disturbances associated with larger common plans of development.
Does the project qualify for this HCOC Exemption?
Y N
If Yes, HCOC criteria do not apply.
HCOC EXEMPTION 2 : T he volume and t ime of c onc ent rat ion1 of storm wat er runoff for t he post - development condition is not significantly different from the pre-development condition for a 2-year return frequency storm (a difference of 5% or less is considered insignificant) using one of the following methods to calculate:
· Riverside County Hydrology Manual
· Technical Release 55 (TR-55): Urban Hydrology for Small Watersheds (NRCS 1986), or derivatives thereof, such as the Santa Barbara Urban Hydrograph Method · Other methods acceptable to the Co-Permittee
Does the project qualify for this HCOC Exemption?
Y N
If Yes, report results in Table F.1 below and provide your substantiated hydrologic analysis in Appendix 7.
Table F.1 Hydrologic Conditions of Concern Summary
2 year – 24 hour
Pre-condition Post-condition % Difference
Time of
Concentration
N/A N/A N/A
Volume (Cubic Feet) N/A N/A N/A
1 Time of concentration is defined as the time after the beginning of the rainfall when all portions of the drainage basin are contributing to flow at the outlet.
- 24 -
HCOC EXEMPTION 3 : All downstream conveyance channels to an adequate sump (for example, Prado Dam, Lake Elsinore, Canyon Lake, Santa Ana River, or other lake, reservoir or naturally erosion resistant feature) that will receive runoff from the project are engineered and regularly maintained to ensure design flow capacity; no sensitive stream habitat areas will be adversely affected; or are not identified on the Co-Permittees Hydromodification Sensitivity Maps.
Does the project qualify for this HCOC Exemption?
Y N
If Yes, HCOC criteria do not apply and note below which adequate sump applies to this HCOC qualifier:
Project drains to Lake Elsinore, map has been added in this report to demonstrate this project is HCOC exempt.
F.2 HCOC Mitigation
If none of the above HCOC Exemption Criteria are applicable, HCOC criteria is considered mitigated if they meet one of the following conditions:
a. Additional LID BMPS are implemented onsite or offsite to mitigate potential erosion or habitat impacts as a result of HCOCs. This can be conducted by an evaluation of site-specific conditions utilizing accepted professional methodologies published by entities such as the California Stormwater Quality Association (CASQA), the Southern California Coastal Water Research Project (SCCRWP), or other Co-Permittee approved methodologies for site-specific HCOC analysis.
b. The project is developed consistent with an approved Watershed Action Plan that addresses HCOC in Receiving Waters.
c. Mimicking the pre-development hydrograph with the post-development hydrograph, for a 2- year return frequency storm. Generally, the hydrologic conditions of concern are not significant, if the post-development hydrograph is no more than 10% greater than pre-development hydrograph. In cases where excess volume cannot be infiltrated or captured and reused, d i s c h a r g e f r o m t h e s i t e m u s t b e l i m i t e d t o a f l o w r a t e n o g r e a t e r t h a n 1 1 0 % o f t h e p r e - development 2-year peak flow.
Be sure to include all pertinent documentation used in your analysis of the items a, b or c in Appendix 7. - 25 -
Section G: Source Control BMPs
Source control BMPs include permanent, structural features that may be required in your project plans — such as roofs over and berms around trash and recycling areas — and Operational BMPs, such as regular sweeping and “housekeeping”, that must be implemented by the site’s occupant or user. The MEP standard typically requires both types of BMPs. In general, Operational BMPs cannot be substituted for a feasible and effective permanent BMP. Using the Pollutant Sources/Source Control Checklist in Appendix 8, review the following procedure to specify Source Control BMPs for your site:
1. Identify Pollutant Sources : Review Column 1 in the Pollutant Sources/Source Control Checklist.
Check off the potential sources of Pollutants that apply to your site.
2. Note Locations on Project-Specific WQMP Exhibit : Note the corresponding requirements listed in Column 2 of the Pollutant Sources/Source Control Checklist. Show the location of each Pollutant source and each permanent Source Control BMP in your Project-Specific WQMP Exhibit located in Appendix 1.
3. Prepare a Table and Narrative: Check off the corresponding requirements listed in Column 3 in the Pollutant Sources/Source Control Checklist. In the left column of Table G.1 below, list each potential source of runoff Pollutants on your site (from those that you checked in the Pollutant Sources/Source Control Checklist). In the middle column, list the corresponding permanent, Structural Source Control BMPs (from Columns 2 and 3 of the Pollutant Sources/Source Control Checklist) used to prevent Pollutants from entering runoff. Add additional narrative in this column that explains any special features, materials or methods of construction that will be used to implement these permanent, Structural Source Control BMPs.
4. Identify Operational Source Control BMPs: To complete your table, refer once again to the Pollutant Sources/Source Control Checklist. List in the right column of your table the Operational BMPs that should be implemented as long as the anticipated activities continue at the site. Copermittee stormwater ordinances require that applicable Source Control BMPs be implemented; the same BMPs may also be required as a condition of a use permit or other revocable Discretionary Approval for use of the site.
Table G.1 Permanent and Operational Source Control Measures Potential Sources of Runoff
pollutants
Permanent Structural Source
Control BMPs
Operational Source Control BMPs
On-Site Strom Drain Inlets Mark all inlets with the words “Only Rain Down the Storm Drain” or
s i m i l a r . C a t c h B a s i n M a r k e r s m a y b e available from the Riverside County
Flood Control and Water Conservation
District, call 951.955.1200 to verify.
· Maintain and periodically repaint
or replace inlet markings
· Provide Stormwater pollution
prevention information to new site
owners, lessees, or operators.
· See applicable optional BMPs in
Fact Sheet SC-44, “Drainage System
Maintenance,” in the CASQA
Stormwater Quality Handbooks at
www.cabmphandbooks.com
- 26 -
Include the following in lease
agreements: “Tenant 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 State that final landscape plans will accomplish all of the following.
· Preserve existing native trees,
shrubs, and ground cover to the
maximum extent possible.
· Design landscaping to minimize
irrigation and runoff, to promote
surface infiltration where
appropriate, and to minimize the
use of fertilizers and pesticides that
can contribute to stormwater
pollution.
· Where landscaped areas are used
to retain or detain stormwater,
specify plants that are tolerant to
saturated soil conditions.
· Consider using pest-resistant
plants, especially adjacent to
hardscape.
· To insure successful establishment,
select plants appropriate to site
soils, slopes, climate, sun, wind,
rain, land use, air movement,
ecological consistency, and plant
interactions.
· Maintain landscaping using
minimum or no pesticides.
· See applicable operational BMPs
in “What you should know for….
Landscape and Gardening” at
http://rcflood.org/stormwater/
Provide IPM information to new
owners, lessees, and operators.
Pools, Spas, Ponds, Decorative
Fountains, and other water features
If the Co-Permittee requires pools to
be plumbed to the sanitary sewer,
place a note on the plans and state in
the narrative that this connection will
be made according to local
requirements.
See applicable operational BMPs in
“Guidelines for Maintaining Your
Swimming Pool, Jacuzzi and Garden
Fountain” at
http://rcflood.org/stormwater/
Roofing, gutters, and trim Avoid roofing, gutters, and trim made of copper or other unprotected
metals that may leach into runoff.
Plazas, Sidewalks, and Parking Lots,
Streets
· HOA will set a sweeping schedule
for, sidewalks, and parking lots
regularly to prevent accumulation
of litter and debris. Collect debris
from pressure washing to prevent
entry into the storm drain system.
Collect wash water containing any
cleansing agent or degreaser and
discharge to the sanitary sewer not
to a storm drain.
Street Sweeping (N5)
Man-made & irrigated slopes
and landscaped areas
· Protect slopes and channels (S5)
· Hillside Landscaping (S12)
· Irrigation System and Landscape
Management (N3)
- 27 -
· Irrigation systems and landscape
design should follow as a guide the
specifications and
recommendations of the Water
Conservation Act of 2006, AB1881
(Laird) and conform to the
standards and requirements of the
City’ landscape requirements.
Irrigation systems shall employ
control systems and be designed to
conserve water. The landscape
design shall incorporate native and
drought tolerant vegetation with
low irrigation requirements. See
CASQA SD-10 and SD-12 BMP Fact
Sheets in and other landscape
literature in WQMP for additional
information.
Irrigation and landscape maintenance
should be performed on a regular
basis throughout the year. See CASQA
SC-41 or SD-10 and SD-12BMP Fact
Sheets in WQMP for additional
information
· Inspect landscape areas twice
annually (before and after the rainy
season) and the irrigation system
quarterly for proper functioning.
· Maintenance should be performed
every 2 weeks or as needed.
· Landscape maintenance should
include mowing, weeding,
trimming, removal of trash &
debris, repair of erosion, re-
vegetation, and removal of cut &
dead vegetation.
· Irrigation maintenance
should include the repair of
leaky or broken sprinkler
heads, the maintaining of
timing apparatus accuracy,
and the maintaining of shut
off valves in
Park Site · Efficient Irrigation (S4) · Common Area Litter Control (N4)
Extended Detention Basins · Inspect landscape areas twice annually (before and after the rainy
season) and the irrigation system
quarterly for proper functioning.
· Maintenance should be performed
every 2 weeks or as needed.
Landscape maintenance should
include mowing, weeding,
trimming, removal of trash &
debris, repair of erosion, re-
vegetation, and removal of cut &
dead vegetation.
· Irrigation maintenance
should include the repair of
leaky or broken sprinkler
heads, the maintaining of
timing apparatus accuracy,
and the maintaining of shut
off valves in control basins
shall be inspected and
maintained on a regular
basis to insure their
operational adequacy. See
CASQA SC-44 BMP Fact
Sheet in WQMP for
additional information.
· before the onset of the rainy
season (Oct 1 to May 1), once
during the rainy season, and once
after the rainy season.
· Maintenance should include
removal of trash, debris, &
sediment and the repair of any
deficiencies or damage that may
impact water quality.
· The property owner will
assume the responsibility for
all on-site drainage facility
inspection, maintenance,
and funding.
- 28 -
Section H: Construction Plan Checklist
Populate Table H.1 below to assist the plan checker in an expeditious review of your project. The first two columns will contain information that was prepared in previous steps, while the last column will be populated with the corresponding plan sheets. This table is to be completed with the submittal of your final Project-Specific WQMP.
Table H.1 Construction Plan Cross-reference
BMP No. or ID BMP Identifier and Description Corresponding Plan Sheet(s) DMA A EXTENDED DETENTION BASIN NO 1 SEE ATTACHED TENTATIVE MAP Note that the updated table — or Construction Plan WQMP Checklist — is o n l y a r e f e r e n c e t o o lto f a c i l i t a t e a n e a s y c o m p a r i s o n o f t h e c o n s t r u c t i o n p l a n s t o y o u r P r o j e c t - S p e c i f i c W Q M P . C o - P e r m i t t e e staff can advise you regarding the process required to propose changes to the approved Project-Specific WQMP.
- 29 -
Section I: Operation, Maintenance and Funding
The Copermittee will periodically verify that Stormwater BMPs on your site are maintained and continue to operate as designed. To make this possible, your Copermittee will require that you include in Appendix 9 of this Project-Specific WQMP:
1. A means to finance and implement facility maintenance in perpetuity, including replacement cost.
2. Acceptance of responsibility for maintenance from the time the BMPs are constructed until responsibility for operation and maintenance is legally transferred. A warranty covering a period following construction may also be required.
3. An outline of general maintenance requirements for the Stormwater BMPs you have selected.
4. Figures delineating and designating pervious and impervious areas, location, and type of Stormwater BMP, and tables of pervious and impervious areas served by each facility. Geo- locating the BMPs using a coordinate system of latitude and longitude is recommended to help facilitate a future statewide database system.
5. A separate list and location of self-retaining areas or areas addressed by LID Principles that do not require specialized O&M or inspections but will require typical landscape maintenance as noted in Chapter 5, pages 85-86, in the WQMP Guidance. Include a brief description of typical landscape maintenance for these areas.
Y o u r l o c a l C o - P e r m i t t e e w i l l a l s o r e q u i r e t h a t y o u p r e p a r e a n d s u b m i t a d e t a i l e d S t o r m w a t e r B M P Operation and Maintenance Plan that sets forth a maintenance schedule for each of the Stormwater BMPs built on your site. An agreement assigning responsibility for maintenance and providing for inspections and certification may also be required.
Details of these requirements and instructions for preparing a Stormwater BMP Operation and Maintenance Plan are in Chapter 5 of the WQMP Guidance Document.
Maintenance Mechanism: Home Owners’ Association (HOA)
W i l l t h e p r o p o s e d B M P s b e m a i n t a i n e d b y a H o m e O w n e r s ’ A s s o c i a t i o n ( H O A ) o r P r o p e r t y O w n e r s Association (POA)?
Y N
Include your Operation and Maintenance Plan and Maintenance Mechanism in Appendix 9. Additionally, include all pertinent forms of educational materials for those personnel that will be maintaining the proposed BMPs within this Project-Specific WQMP in Appendix 10.
Operation, maintenance and funding Mechanism to be determined during final engineering. - 30 -
Appendix 1: Maps and Site Plans
Location Map, WQMP Site Plan and Receiving Waters Map
LOCATION MAP
VICINITY MAP
ALESSANDRO BLVD
CACTUS AVENUE
COTTONWOOD AVENUE
NASON STREET
OLIVER STREET
MORENO BEACH DRIVE
OLIVER STREET
BAYAVE
LOCATION MAP
WQMP SITE PLAN
LEGEND
A
0.9 3/18/2024
SUNSET CROSSINGS
ENGINEERING CONSULTANTS
WQMP SITE PLAN
A
30.07 * ** *
*
DEDB NO. 1
DEDB NO. 1
DMA A-1
DMA A-1
DMA A-2
STREET K
STREET L
STREET M
STREET N
STREET A
STREET O
STREET Q
STREET A
INTERIM
STREET D
STREET E
STREET G
STREET CSTREET H
STREET F
STREET I
STREET J
BAY AVE
TRACT NO 38442
(REFER TO SEPARATELY WQMP REPORT)
TRACT NO 38443
DESILTING BASIN
DMA A-2
*
*
EFFICIENT IRRIGATION SYSTEM
PARK AREA
RECEIVING WATERS MAP
8/30/2022
SUNSET CROSSINGS
6000 3000 6000 12000 180000
SCALE: 1"=6000'
0 SCALE: 1"=6000'
ENGINEERING CONSULTANTS
RECEIVING WATERS MAP
18000
- 31 -
Appendix 2: Construction Plans
Grading and Drainage Plans
STREET A
CEDAR COURT
COTTONWOOD AVE.
BAY AVE
STREET D
STREET A
STREET F
STREET C
STREET B
STREET G
STREET D
STREET E
LOT 'A'
LOT 'B'
LOT 'I'
LOT 'C'
LOT 'D'
LOT 'E'
LOT 'H'
LOT 'G' LOT 'F'
LOT 'J'
LOT 'M'
LOT 'N'
LOT 'O'
LOT 'P'
BAY AVE
LOT 'T'
LOT 'Q'
LOT 'L'
WQ BASIN
LOT 'K'
LOT 'R'
LOT 'S'
LOT 'U'
ENGINEERING CONSULTANTS
SRXWK MDLQ SWUHHW SXLWH
CRURQD CA
ENGINEERING CONSULTANTS
200 South Main Street, Suite 300
Corona, CA 92882 (951) 280-3300
STREET A
COTTONWOOD AVE.
BAY AVE
STREET A
STREET C
STREET B
STREET D
STREET E
LOT 'A'
LOT 'B'
LOT 'I'
LOT 'C'
LOT 'D'
LOT 'E'
LOT 'J'
LOT 'M'
LOT 'N'
LOT 'O'
LOT 'P'
LOT 'T'
LOT 'L'
WQ BASIN
LOT 'K'
LOT 'S'
LOT 'U'
EN*INEERIN* CONSULTANTS
SRXWK MDLQ SWUHHW SXLWH
CRURQD CA
STREET A
CEDAR COURT
STREET D
STREET F
STREET G
LOT 'A'
LOT 'H'
LOT 'G'
LOT 'F'
LOT 'O'
BAY AVE
LOT 'Q'
LOT 'L'
LOT 'A'
STREET
MARTHA CRAWFORD LOT 'R'
E1G,1EER,1G CO1SULTA1TS
SRXWK MDLQ SWUHHW SXLWH
CRURQD CA
STREET A
COTTONWOOD AVE.
BAY AVE
STREET A
STREET C
STREET B
STREET D
STREET E
LOT 'A'
LOT 'B'
LOT 'I'
LOT 'C'
LOT 'D'
LOT 'E'
LOT 'J'
LOT 'M'
LOT 'N'
LOT 'O'
LOT 'P'
LOT 'T'
LOT 'L'
WQ BASIN
LOT 'K'
LOT 'S'
LOT 'U'
EN*INEERIN* CONSULTANTS
SRXWK MDLQ SWUHHW SXLWH
CRURQD CA
STREET A
CEDAR COURT
STREET D
STREET F
STREET G
LOT 'A'
LOT 'H'
LOT 'G' LOT 'F'
BAY AVE
LOT 'Q'
LOT 'L'
STREET
MARTHA CRAWFORD LOT 'R'
E1G,1EER,1G CO1SULTA1TS
SRXWK MDLQ SWUHHW SXLWH
CRURQD CA
- 32 -
Appendix 3: Soils Information
Geotechnical Study and Other Infiltration Testing Data
PERCOLATION TEST
SOILS REPORT
November 23, 2022
Project No. 13169.003
Highpointe MV 1 LLC
530 Technology, Suite 100
Irvine, California 92618
Attention: Mr. Ross Yamaguchi, Senior Project Manager
Subject: Summary of Soil In filtration Feasibility
Proposed Sunset Crossings Residential Development
Tract 38443 (North Tract), City of Moreno Valley, California Reference: Leighton and Associates, Inc., 2022 Design-Level geotechnical Exploration Proposed 50-Acre Residential Development South of Cottonwood Avenue North of Alessandro Boulevard, May 19.
In accordance with a request by Mr. Dillon Strand, PE, of Proac tive Engineering Consultants, this letter summarizes the results our percolation testing and provides our opinion regarding onsite infiltration of storm water. As presented in our above referenced report, the (un-factored) infiltration rates range from 0.08 to 1.29 inch/hr and the proposed remedial grading requires rem oval and compaction of the upper 1 2 to 14 feet of soils to reduce excessive settlement due to loose and collapsible soils.
Based on the above, it is our opinion that site soils present unfavorable conditions for bio- retention or onsite infiltration of storm water and other options for design of WQMP should be considered for this project.
If any questions arise concerning the above please contact us at (866) LEIGHTON; or the telephone extensions or e-mail addresses listed below.
Respectfully submitted,
LEIGHTON AND ASSOCIATES, INC.
Jeff L. Hull, CEG
Associate Geologist
Ext. 4265, [email protected]
Simon Saiid, GE
Senior Principal Engineer
Ext. 8013, [email protected]
Distribution: (1) Addressee (PDF copy via email)
DESIGN-LEVEL GEOTECHNICAL EXPLORATION
PROPOSED 50-ACRE RESIDENTIAL DEVELOPMENT
SOUTH OF COTTONWOOD AVENUE
NORTH OF ALESSANDRO BOULEVARD
MORENO VALLEY, CALIFORNIA
Prepared For HIGHPOINTE MV 1 LLC
530 TECHNOLOGY, SUITE 100
IRVINE, CALIFORNIA 92618
Prepared By LEIGHTON AND ASSOCIATES, INC.
41715 ENTERPRISE CIRCLE, N SUITE103
TEMECULA, CALIFORNIA 92590
Project No. 13169.003
May 19, 2022
May 19,
2022
Project No. 13169.003
Highpointe MV 1 LLC
530 Technology, Suite 100
Irvine, California 92618
Attent
ion: Mr. Ross Yamaguchi, Senior Project Manager
Subj
ect: Design-Level Geotechnical Exploration
Proposed 50-Acre Residential Development
South of Cottonwood Avenue, North of Alessandro Boulevard Moreno Valley, California
In acc
ordance with your request and authorization, we provide this report documenting findings and conclusions of our site geotechnical exploration, pertinent to development of the subject property for residential use. Our study was undertaken to evaluate the general distribution and engineering characteristics of surface/subsurface earth units, and impacts of geologic hazards, and develop geotechnical recommendations for design and construction. A deposit of settlement-prone alluvium at the surface is considered the most significant geotechnical constraint due to its relatively high collapse potential, warranting over-excavation and recompaction to depths of 7 to 9 feet and 12 to 14 feet in north and south site areas, respectively. Provided recommendations presented herein are properly incorporated into project design and construction, the development project is considered suitable from a geotechnical perspective. Once final grading and foundation plans are available, our recommendations should be reviewed to verify conformance with those plans.
We app
reciate the opportunity to work with you on this project. If you have any questions or if we can be of further service, please contact us at (866) LEIGHTON; or specifically at the telephone extensions or e-mail addresses listed below.
Respectfully submitted
LEIGHTON AND ASSOCIATES, INC.
Jeff L. Hull, CEG 2056
Associate Geologist
Ext. 4265, [email protected]
Simon Saiid, GE 2641
Principal Engineer
Ext. 8013, [email protected]
Distribution: (1) Addressee (PDF copy via email)
TABLE O
F CONTENTS
Section Page
1.0 INTRODUCTION ........................................................................................................ 1
1.1 Site Description and Proposed Development ................................................. 1
1.2 Purpose and Scope ......................................................................................... 1
2.0 GEOTECHNICAL AND GEOLOGIC FINDINGS ...................................................... 3
2.1 Regional Geology ............................................................................................ 3
2.2 Site-Specific Geology ...................................................................................... 4
2.3 Groundwater Conditions .................................................................................. 4
2.4 Expansive Soils ............................................................................................... 5
2.5 Soil Sulfate Content ......................................................................................... 5
2.6 Infiltration Testing ............................................................................................ 6
3.0 GEOLOGIC AND SEISMIC HAZARD EVALUATION .............................................. 8
3.1 Faulting ............................................................................................................ 8
3.2 Seismicity ......................................................................................................... 8
3.3 Other Geologic Hazards .................................................................................. 9
3.3.1 Liquefaction Potential ........................................................................... 9
3.3.2 Seismically-Induced Settlement ......................................................... 10
3.3.3 Lateral Spreading ............................................................................... 10
3.3.4 Slope Stability and Seismically Induced Landslides .......................... 10
3.4 Earthquake-Induced Flooding ....................................................................... 10
3.5 Flooding ......................................................................................................... 10
3.6 Land Subsidence ........................................................................................... 11
4.0 SUMMARY OF FINDINGS AND CONCLUSIONS ................................................. 12
5.0 RECOMMENDATIONS ............................................................................................ 13
5.1 General Earthwork Considerations ............................................................... 13
5.1.1 Site Preparation .................................................................................. 13
5.1.2 Remedial Grading .............................................................................. 13
5.1.3 Fill Placement and Compaction ......................................................... 13
5.1.4 Shrinkage and Subsidence ................................................................ 14
5.1.5 Import Soils ......................................................................................... 14
5.1.6 Utility Trenches ................................................................................... 14
5.1.7 Drainage ............................................................................................. 15
5.1.8 Slope Design and Construction ......................................................... 15
5.2 Foundation Design ........................................................................................ 16
5.2.1 Bearing and Lateral Pressures .......................................................... 16
5.2.2 Settlement .......................................................................................... 17
5.2.3 Vapor Retarder ................................................................................... 17
5.3 Temporary Excavation and Shoring Design ................................................. 18
5.4 Preliminary Pavement Design Parameters ................................................... 18
5.5 Retaining Walls .............................................................................................. 19
5.6 Foundation Setback from Slopes .................................................................. 20
5.7 Concrete Flatwork ......................................................................................... 21
6.0 GEOTECHNICAL CONSTRUCTION SERVICES .................................................. 23
7.0 LIMITATIONS ........................................................................................................... 24
8.0 REFERENCES ......................................................................................................... 25
LIST OF TABLES
TABLE 1. CORROSIVITY TEST RESULTS .......................................................................................... 5 TABLE 2. MEASURED INFILTRATION RATE (UNFACTORED) ............................................................... 6 TABLE 3. 2019 CBC-BASED SEISMIC DESIGN PARAMETERS ........................................................... 9 TABLE 4. PAVEMENT SECTION DESIGN ......................................................................................... 18 TABLE 5. RETAINING WALL DESIGN EARTH PRESSURES (STATIC, DRAINED) .................................. 19 TABLE 6. FOOTING SETBACKS ...................................................................................................... 20
Figures
Figure 1 – Site Location Map Rear of Text
Figure 2 – Site Geotechnical Map Rear of Text
Figure 3 – Regional Geology Map Rear of Text
Figure 4 – Regional Fault Map Rear of Text
Figure 5 – Liquefaction Map Rear of Text
Figure 6 – Flood Hazard Zone Map Rear of Text
Figure 7 – Subsidence Map Rear of Text
Appendices
Appendix A – Boring / Test Pit / Infiltration Test Logs Appendix B – Laboratory Test Results
Appendix C – Seismic Design Data and Settlement Analyses Appendix D – General Earthwork and Grading Specifications for Rough Grading Appendix E – Retaining Wall Backfill and Subdrain Detail Appendix F – GBA Important Information About This Geotechnical Engineering Report
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
1.0 INTRODUCTION
1.1 Site Description and Proposed Development
The subject 50-acre property is located south of Cottonwood Avenue and North of Alessandro Boulevard in the City of Moreno Valley, California (N 33.9205, W - 117.1871). The site location and surrounding areas are depicted on attached Figure 1, Site Location Map. The property is currently vacant except for a few existing private ranch-style residential structures located within the north and eastern portions of the site. Surface elevations (El.) range from approximately El. 1640 feet above mean sea level (msl) in the northeast to El. 1590 feet msl in the south, manifest in about 50 vertical feet of overall relief. Offsite areas to the west are lightly developed for commercial and single-family residential use.
Our understanding of the project is based on review of the Moreno Valley Site Plan Exhibit prepared by Proactive Engineering Consultants dated March 17, 2022. The site is currently proposed to be developed as a tract of single-family homes with 241 individual lots. We anticipate that the homes will consist of typical 1- to 2-story wood- framed structures supported by conventional reinforced concrete slab- on-grade floors and/or shallow spread and continuous footings (no subterranean elements).
Vehicular access will be accommodated by a series of internal access roads.
Appurtenant improvements include a network of underground utilities, two ten foot deep water quality management basins, and approximately 3 acres of park space.
1.2 Purpose and Scope
The purpose of this exploration was to evaluate the onsite surface and subsurface soils conditions, and provide geotechnical recommendations for design and construction of the proposed development. More specifically, our scope of our work included the following:
Literature Review – R eview of published geologic maps and reports, and historical aerial photographs and topographic maps readily available on-line or within our in-house technical library. A list of these documents is presented in Section 8.0, References.
Exploratory Borings and Test Pits – Advanced four (4) hollow-stem borings (LB- 1 through LB-4) on the site, on March 4, 2022, extending to depths between 31.5 feet to 51.5 feet below the existing ground surface (bgs). Approximate boring locations are shown on Figure 2, Site Geotechnical Map. Copies of boring logs are presented in Appendix A, Boring / Test Pit / Infiltration Test Logs.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
Bulk and
relatively undisturbed drive samples were collected during drilling for the purpose of field description and geotechnical laboratory testing. The driven samples were obtained using a Modified California Ring sampler conducted in accordance with ASTM Test Method D3550. The samplers were driven for a total penetration of 18 inches using a 140- pound automatic hammer allowed to fall freely from a height of 30 inches. The number of blows per 6 inches of penetration was recorded.
In addition, four (4) exploratory test pits (TP-1 through TP-3, and TP-5) were excavated, logged, and sampled on March 4, 2022 using a rubber-tire backhoe to a maximum depth of approximately 5 feet bgs. Trench logs are presented in Appendix B, Boring / Test Pit / Infiltration Test Logs.
Each boring and test pit was logged in the field by a member of our technical staff under the direct supervision of a State of California Certified Engineering Geologist (CEG). Soil samples were reviewed and described in the field in accordance with the Unified Soil Classification System (USCS). Upon completion, the excavations were backfilled with soil cuttings. Infiltration Testing: For the purpose of infiltration testing, two additional hollow- stem auger borings (LP-1 and LP-2) were advanced near the location of proposed bio-retention basins on March 4, 2022, each to a depth of approximately 13 feet bgs. Results of the percolation testing are presented in Appendix A. Laboratory Testing: Representative soil samples obtained from the subsurface exploration program were selected for testing. A brief description of laboratory testing procedures and laboratory test results are presented in Appendix B, Geotechnical Laboratory Testing. Moisture content and in- situ density are presented within our boring logs (see Appendix A).
Engineering Evaluation – Data collected was reviewed and analyzed by a Geotechnical Engineer (GE) and a Certified Engineering Geologist (CEG). Report Preparation – This report was prepared to document findings and conclusions, and provide design -level geotechnical recommendations addressing the currently proposed development concept.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
2.0 GEOTECHNICAL AND GEOLOGIC FINDINGS
2.1 Regional Geology
The site lies within a prominent natural geomorphic province of California, occupying the southwestern quadrant of the state, referred to as the Peninsular Ranges. This province is characterized by steep, elongated ranges and valleys trending northwestward in orientation. More specifically, the site is situated within the northern portion of the Perris Block, a structural block composed of uplifted Cretaceous and older crystalline bedrock. The Perris Block spans an area approximately 20 miles in width by 50 miles in length, bounded by the San Jacinto Fault Zone to the northeast, the Elsinore Fault Zone to the southwest, the Cucamonga Fault Zone to the northwest, and the Temecula Basin to the south.
The bas
ement rock composing the Perris Block were solidified on the order of several thousand feet below their present near surface location, owing to an apparent uplift of similar magnitudes. The uplift is accommodated by relative displacement along the Elsinore and San Jacinto Fault Zones. The region is typically mantled by alluvial/fluvial clastic deposits of Quaternary age, infilling areas between bedrock highs (see Figure 3, Regional Geology Map).
The infillin
g soil units typically consist of alluvial fan deposits derived either from the erosion of nearby bedrock highs, or distal areas of the valley. The valley floor, and subject property, exhibit a gentle southwesterly sloping/descending profile mainly generated by erosion of the geologically elevated “Badlands” region. This region consists of an uplifted range of erodible bedrock along the San Jacinto Fault northeast of the site. The flat -lying valley surface is locally pierced by elevated conical shaped masses of weathered granitic basement rock. One such outcrop occurs just northeast of the subject property, with heights ascending up to approximately 186 feet above the flat-lying surrounding areas.
More
no valley tends to be transected by various narrow streams entrenched into the fan surface. The stream paths are meandering with the valley plain, except where they encounter areas of hard rock outcrops, where they circumvent around outcrop margins. One such stream defines the northeast site boundary and periodically discharges sediments onto the site as flood deposits.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
2.2 S ite-Specific Geology
Our borings reveal the site is underlain by a thin mantle of tilled topsoil which is not mapped. Underlying this material are sedimentary units interpreted as young and very old Quaternary alluvial fan deposits. The deposits are typically composed of variable lenses of laterally discontinuous silty sands, sandy silts and interla yered poorly-graded sands and lessor fractions of silts and silty clay. Morton et al. (2006) subdivide the on-site alluvial fan deposits into two distinct units as follows:
Young Alluvial Fan Deposits (Qyf) – (Holocene to late Pleistocene): Based on exposures in our borings and test pits this unit underlies a majority of the property, varying from approximately 15 to 30 feet or greater in thickness. Th is unit is characterized as a yellow brown to brown silty sand that is loose to medium dense and unconsolidated to moderately consolidated in texture. It is variable in its distribution within the northern area of the site were we infer it as infilling areas of dissected older underlying units. The younger alluvial deposits are expected to possess very low expansion potential (EI<21). Based on our laboratory testing, these materials are expected to exhibit slight to moderate hydro-collapse potential (3 to 9 percent) in the upper 10 to 15 feet bgs.
Very Old Alluvial Fan Deposits (Qvof) – (middle to late Pleistocene): This unit underlies younger fan deposits to the maximum depth explored (51.5 feet bgs).
It varies in depth across the site, encountered near the surface locally in the northern site areas and deeper within southern site areas. The unit consists of reddish brown silty sands to clayey sands with local gravel, which are loose to dense a nd is unconsolidated to moderately consolidated. Based on our laboratory testing, these deposits also exhibit a slight to moderate hydro-collapse potential (2 to 6 percent) within the upper 10 to 15 feet bgs. The locally increased clay content of this unit suggests it possesses a low expansion potential (EI<51).
Our det
ailed description of subsurface soil units, and depths to the contacts of these units, are presented within attached Appendix A, Boring / Test Pit / Infiltration Test Logs.
2.3 Groundwater Conditions
At the time of our exploration, no groundwater was encountered to the maximum depth explored (51.5 feet bgs ). According to published groundwater studies encompassing the site area, the depth to groundwater beneath the site in circa 1971 was on the order of 190 feet bgs (USGS, SP 1781). The same publication noted the groundwater table rose to an elevation of around 1,450 feet msl by 2006, corresponding to a depth of approximately 140 feet bgs. Groundwater at this depth Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
is not anticipated to pose a constraint to proposed site grading. However, fluctuations in the depth of groundwater levels or soil moisture beneath the site, and/or the development of temporary perched water conditions, can occur seasonally as a result of storm events, storm water runoff, stormwater infiltration, or landscape irrigation.
2.4 Expansive Soils
As indicated above, the site near surface soils consist of silty sand of low plasticity and expected to possess very low expansion potential (EI< 21). The expansion potential of the very old alluvial fan deposits may be higher where containing locally greater concentrations of clay (EI<51).
The inherent variability in alluvial sediment distribution is such that more or less clayey soils may be encountered on the site, in areas bey ond the location of our exploration. The presence of disposition of any excessively clayey soils will be evaluated during grading. And conformance testing of as -graded pad surfaces performed to verify design parameters. Although not anticipated, the pot ential to encounter moderately expansive soils (EI<51) during grading, and inadequately mix or dispose of them such that higher concentrations result at finish pad grade, warranting use of post-tension slab systems, cannot be precluded.
2.5 Soil Sulfate Content
Based on our previous experience in the site area, we anticipate a negligible concentration of soluble sulfates in onsite soils. Additional corrosion testing should be performed on representative finish grade soils at the completion of rough grading.
A representative bulk sample of near surface soil collected from a depth between 0 and 5 feet bgs in boring LB-3, was tested to evaluate corrosion potential. Results of chemical analysis tests are attached in Appendix B, Laboratory Test Results. A summary of the test results is presented below in Table 1.
Table 1. Corrosivity Test Results
Test Parameter Test Results
(LB-3 @ 0-5’) General Classification of Hazard
Water-Soluble Sulfate-
SO4 in Soil (ppm) 140 Negligible sulfate exposure to buried concrete-S0 Exposure Class
Water-Soluble Chloride
in Soil (ppm) 20 Non-corrosive to buried concrete (per
Caltrans Specifications)
pH 7.40 Mildly alkaline
Minimum Resistivity
(saturated ohm-cm) 2900 Moderately corrosive to buried
ferrous pipes
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
2.6 Infiltra
tion Testing
Two (2) field percolation tests were performed in the general location of planned bio-retention basin, at planned basin invert depths, within shallow in-situ sandy alluvial soils. The testing was performed in general accordance with the Riverside County - Low Impact Development BMP Design Handbook (Riverside County Flood Control and Water Conservation District, 2011).
Each
well was constructed by installing two -inch-diameter PVC casing into the boreholes, screened within test zones and solid above perforated sections.
Borehole annular spaces were infilled with clean sand (#3 Monterey Sand) to approximately 1-foot above the screen zone. The wells were then pre-soaked prior to the testing in an attempt to model the behavior of stormwater quality control devices during a design storm event. After the conclusion of the percolation testing, the well casings were removed and the test holes backfilled with naive soil tailings.
Based on
the results of pre-soaking and initial readings, percolation testing in LP- 1 and LP-2 was performed using the falling head test procedure, where the drop of water levels inside the well were recorded over the testing period. Measured percolation rates were calculated by dividing the rate of discharge (cubic inches per hour) by the infiltration surface area, or flow area (square inches). Discharge volume was calculated by adding the total volume of water that dropped within the PVC pipe and annulus incorporating a porosity reduction factor to account for the filter pack material. The flow area was based on the average water height within the slotted pipe section of the test well only.
The result
s of the percolation testing and resultant measured (un- factored) rates of infiltration obtained from the testing are presented below in Table 2. Detailed test data is presented in Appendix A, Boring / Test Pit / Infiltration Test Logs.
Table 2. Measured Infiltration Rate (Unfactored)
Percolation Test
Boring/Well
Designation
Percolation
Test Method
Approximate Depth of
Test Zone Below
Ground Surface (feet)
Unfactored*
Infiltration Rate
(in/hr)
LP-1 Falling Head 10-13 1.29
LP-2 Falling Head 10-13 0.08
Note: The invert elevation of any stormwater infiltration shall be set back at least 15 feet, and outside a 1:1 plane drawn down and out from the bottom of adjacent foundations.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
Measured (un-factored) rates of infiltration indicate that onsite infiltration at the specific location and depth of LP-1 is more favorable than the LP-2 location. The differences in rates as attributable to the deposits encountered within the test zones. The LP -1 test was performed in the young alluvial fan deposits, the LP-2 test was conducted in the very old alluvial fan deposit.
The infiltr
ation rates are the product of small-scale test performed at specific locations and depths. Actual infiltration rates within the area of a proposed infiltration device can vary from that yielded by our tes ting. Therefore, care must be used in the selection of infiltration rate for use in design and the potential for variances in soil conditions (fines content) that could significantly affect long-term field performance.
Infiltration rates can be expected to decline over time between maintenance cycles as BMP surface become occluded and particulates accumulate in the infiltrative layer of testing suggest some lateral variability in both infiltration rates and fines content.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
3.0 GEOLOGIC AND SEISMIC HAZARD EVALUATION
3.1 Faulting
Known surface faults in the region are mapped on Figure 4, Regional Fault Map. Our review of available in-house literature indicates the mapped presence of no known active faults on or crossing the site, and the site is not located within a currently - designated Alquist-Priolo Earthquake Fault Zone (CGS, 1999; Bryant and Hart, 2007). A surface fault rupture hazard evaluation is, therefore, not mandated for this site. In addition, no currently known active faults have been mapped within the vicinity of the site having a potential for surface fault rupture. Given an absence of known faults, potential risk for surface fault rupture at this site is low.
3.2 Seismicity
Historically, the San Jacinto Fault Complex has produced earthquakes in the magnitude range of 6.0Mw to 7.6Mw (Moment magnitude). In roughly the last 100 years (1903 through 2020), 9 major quakes in the range of 6.0Mw to 7.6Mw have occurred within a 50-mile radius of the subject site. Each of these large quakes has produced moderate to severe damage to buildings and roads, and several have resulted in fatalities (USGS, 1971). The frequency and relatively short recurrence interval of surface rupture for the San Jacinto Fault has resulted in many events during Holocene time with at least 16 documented in the past 3,700 years (Onderdonk et al., 2018).
Common
throughout most of Southern California is a potential for strong ground shaking generated by moderate to s evere earthquakes. The intensity of ground shaking at a given location depends primarily upon earthquake magnitude, site distance from the source, and site response (soil type) characteristics. S eismic coefficients for the subject site were calculated utilizing an interact ive program on current United States Geological Survey (USGS) website using ASCE 7 -16 procedures. Based on the results of seismic profiling, the soil sediments underlying the site are classified as Site Class D. As such, the site-specific seismic coefficients are as presented below in Table 3. Copies of seismic analysis data are attached in Appendix C, Seismic Design Data and Settlement Analyses.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
Table 3. 2019 CBC-Based Seismic Design Parameters
Categorization/Coefficient Design
Value
Site Latitude: 33.9205, Site Longitude: -117.1871
Site Class: D
Mapped Spectral Response Acceleration at Short Period (0.2 sec), SS 1.92g Mapped Spectral Response Acceleration at Long Period (1 sec), S1 0.76g Short Period (0.2 sec) Site Coefficient, Fa 1.0
Long Period (1 sec) Site Coefficient, Fv 1.71
Adjusted Spectral Response Acceleration at Short Period (0.2 sec), SMS 1.92g Adjusted Spectral Response Acceleration at Long Period (1 sec), SM1 1.29g1 Design Spectral Response Acceleration at Short Period (0.2 sec), SDS 1.28g Design Spectral Response Acceleration at Long Period (1 sec), SD1 0.86g1 PGA adjusted for Site Class, PGAM = FPGA *PGA 0.89g
g = Gravity acceleration
*Per Exception 2 in Section 11.4.8 of ASCE 7-16, seismic response coefficient CS to be determined by Eq.
12.8-2 for values of T < 1.5Ts and taken as equal to 1.5 times the value computed in accordance with either Eq.
12.8-3 for TL > T > 1.5Ts or Eq. 12.8-4 for T > TL
The project structural engineer should confirm if the above applies for the proposed structures, else a site–specific ground motion analysis may be required.
3.3 Other Geologic Hazards
Other site geologic hazards associated with this site are discussed in subsections below.
3.3.1 Liquefaction Potential
According to the Liquefaction Map published on the ESRI ArcGIS website the site is defined as having a low liquefaction susceptibility, see Figure 5, Liquefaction Map. This regional scale mapping represents only a general distribution of the liquefaction potential, and not a definitive indication that liquefaction can or will occur. It is intended to inform practitioners of its potential so that appropriate hazard analyses may be incorporated into a development project. The southern areas of the site correspond to mapped areas of Quaternary Young Alluvial Fan deposits. This unit is defined as having a moderate susceptibility to liquefaction. These younger alluvial fan deposits are underlain by Pleistocene age very old fan deposits that are generally not susceptible to liquefaction. Given an absence of groundwater encountered beneath the site at or above a depth of 50 feet bgs, the potential constraint to the proposed development due to liquefaction and related seismic-induced settlement is considered very low.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
3.3.2 Seismically-Induced Settlement
During a strong seismic event, and in the absence of groundwater, seismically-induced settlement can still occur within loose to medium dense and dry or moist granular soils. Settlement caused by ground shaking is often non-uniformly distributed, which can result in differential settlement. Based on the design earthquake and a Peak Ground Acceleration (PGA) of 0.89g, the magnitude of dynamic dry settlement is estimated to be on the order of approximately 4.0 inches (see Appendix C), assuming remedial grading is performed in compliance with Section 5.1 of this report. Given the similar lithology of the onsite soil units and implementation of propo sed remedial grading, anticipated dynamic settlement is expected to occur over a widespread area of the site. As such, the differential settlement is not expected to exceed 1-inch in a 30-foot horizontal distance.
3.3.3 Lateral Spreading
As the potential for liquefaction is expected to be very low, and the property is well constrained laterally, the potential for earthquake -induced lateral spreading at the site is considered negligible.
3.3.4 Slope Stability and Seismically Induced Landslides The site is relatively flat in topographic relief and not designated on County of Riverside hazard maps as occurring within a landslide hazard zone. No slopes or other elevated areas of any significance exist on or adjacent to the property which could be potential source of landslides. Based on the above, the potential for slope instability or seismically induced landslides is considered negligible.
3.4 Earthquake-Induced Flooding
The potential for earthquake-induced flooding can relate to the failure of nearby dams or other water-retaining structures as a result of earthquakes. There are no nearby water retaining structures and the site is not located within a mapped Dam Inundation Risk zone. The potential for earthquake induced flooding to affect this site is considered negligible.
3.5 Flooding
Federal Emergency Management Agency (FEMA) flood insurance rate map Nos. 06065C0770G and 06065C0765G (FEMA, 2008), indicate the project site is located within Zone X, designated as “an area of minimal flood hazard.” As shown on Figure 6, Flood Hazard Zone Map, the site is not located within a flood hazard zone.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
3.6 Land Subsidence
Land subsidence refers to the sinking or gradual downward settlement and compaction of soil deposits, commonly associated with the extraction of deep groundwater and/or petroleum resources from a region. Subsidence can be manifest at the surface by a broad lowering of topography in the form of depression(s), often recognized within sedimentary basins by the formation of arcuate tension cracking along basin margins, with little or no lateral movement. According to the County of Riverside, the site is mapped within a zone susceptible to subsidence, based only on the presence of geologic and/or hydrogeologic conditions similar to areas having experienced such hazards in the past. The mapped limits of this zone are shown on attached Figure 7, Subsidence Map. Given the site is not situated near any active faults or basin margin, the effects of any potential subsidence on the development is considered to be low.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
4.0 SUMMARY OF FINDINGS AND CONCLUSIONS
A summary of our geologic and geotechnical findings and conclusions are presented below:
The relatively loose near surface alluvial soils possess relatively significant degree of potential collapse (up to 9 percent). As such, over-excavation and recompaction to depths varying from 7 to 14 feet will be required to reduce potential differential settlement to tolerable limits. More specific grading recommendations are provided in Section 5.1.2 below.
Groundwater was not encountered within the maximum depth of our exploration (51.5 feet bgs). Regional literature indicates groundwater occurs at depths of at least 140 feet bgs. Given the above, groundwater is expected to pose no constraint to site development.
Results of s hallow field percolation testing within the proposed central bio -retention basin, at the invert depth tested, is considered feasible for use as a part of on- site stormwater system design.
Results of shallow field percolation testing within the bio-retention basin planned near the southern site margin is not considered suitable for infiltration at the invert depth tested.
The site is not located within an Alquist -Priolo Earthquake Fault Zone, nor was any evidence of active faulting observed on or as projection towards the site. Surface fault rupture is not considered a site hazard.
The close proximity of major faults and historical earthquakes indicate occurrence of strong ground shaking at the site is likely during its economic life-span. Deposits of young alluvial fan material are expected to possess a very low expansion potential (EI<21), and, very old alluvial fan materials are expected to possess a low expansion (EI<51).
The potential exists to encounter very old alluvial sediments wit h locally higher clay concentrations.
Materials generated by both the younger and very old geologic units on the site are expected to be suitable for use as compacted fill, provided it is relatively free of organic material and debris.
The s ite soil units can be readily excavated, processed and compacted using a conventional grading equipment in good repair.
Finish building pads, slope faces and other graded surfaces will be susceptible to erosion if left unprotected. This risk can be reduced through in stallation of certain control measures including but not limited to a jute net cover, erosion control blankets, straw wattles, or other similar methods of protection.
Caving and raveling of soils in un-shor ed excavations should be expected.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
5.0 RECOMMENDATION S
The following geotechnical recommendations are provided for project site grading and construction.
5.1 General Earthwork Considerations
All site grading should be performed in accordance with applicable local regulatory codes, and project specifications prepared by applicable de sign professional.
Detailed grading recommendations are attached herein as Appendix D, General Earthwork and Grading Specifications for Rough Grading.
5.1.1 Site Preparation
Prior to construction, the site should be cleared of any vegetation, trash, and/or debris within the area of proposed grading. These materials should be removed from the site. Any underground obstructions onsite should be removed. Existing utility lines will need to be removed and/or rerouted where interfering with the proposed construction. Any resulting excavation cavities should be properly backfilled and compacted. All unsuitable earth deposits should be excavated and removed from the footprints of proposed buildings/structures prior to fill placement. Any existing undocumented fill will need to be removed from areas of planned structural improvements.
5.1.2 Remedial Grading
The upper 7 to 9 feet of existing surficial soil in the northern portion of the site (north of projected Bay Avenue) should be removed/over -excavated and recompacted prior to foundation construction or placement of any additional fill. Similarly, the upper 12 to 14 feet of existing surficial soil in the southern portion of the site (south of Bay Avenue) should be removed/over-excavated and recompacted . The removal limit s should be established via 1:1 (horizontal: vertical) projection from the edges of structural fills ( soils supporting settlement -sensitive structures ) downward and outward to competent material identified by the geotechnical consultant. Removal will also include benching into competent material as the fills rise. Areas adjacent to existing structures/roadways or property limits may require special considerations and monitoring. Deeper removals may be required in local areas based on prevailing soils conditions.
5.1.3 Fill Placement and Compaction
Fill soils should be placed in loose lifts not exceeding 8 inches, moisture - conditioned to within 2 percent of optimum moisture content for sandy soils and at least 4 percent above optimum moisture content for clayey soils (not Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
anticipated), and compacted to a minimum of 90 percent of the maximum dry density as determined by ASTM Test Method D 1557.
5.1.4 Shrinkage and Subsidence
The volume change of excavated onsite materials upon compaction is expected to vary with materials, volume of roots and deleterious materials, density, insitu moisture content, location, and compaction effort. The in-place and compacted densities of soil materials vary and accurate overall determination of shrinkage and bulking cannot be made. Therefore, we recommend site grading include, if possible, a balance area or ability to adjust import quantities to accommodate some variation. Based on our experience with similar materials, we anticipate 10 to 18 percent shrinkage in the upper 10 to 15 feet of alluvium. Subsidence due solely to scarification, moisture conditioning and recompaction of the exposed bottom of overexcavation, is expected to be on the order of 0.15 foot. This should be added to the above shrinkage value calculations for the recompacted fill zone.
5.1.5 Import Soils
Import soils and/or borrow sites, if needed, should be evaluated by the geotechnical consultant prior to import. Import soils should be uncontaminated, granular in nature, free of organic material (loss on ignition less-than 2 percent), have a very low expansion potential (with an Expansion Index less than 12) and have a low corrosion impact to the proposed improvements.
5.1.6 Utility Trenches
Utility trenches should be backfilled with compacted fill in accordance with Sections 306-1.2 and 306-1.3 of the Standard Specifications for Public Works Construction, (“Greenbook”), 2021 Edition (or most recent). Fill material above the pipe zone should be placed in lifts not exceeding 8 inches in uncompacted thickness and should be com pacted to at least 90 percent relative compaction (ASTM D 1557) by mechanical means only. Site soils may generally be suitable as trench backfill provided these soils are screened of rocks over 1½ inches in diameter and organic matter. If imported sand is used as backfill, the upper 3 feet in building and pavement areas should be compacted to 95 percent. The upper 6 inches of backfill in all pavement areas should be compacted to at least 95 percent relative compaction.
Where granular backfill is used in utility trenches adjacent moisture sensitive subgrades and foundation soils, we recommend that a cut -off “plug” of impermeable material be placed in these trenches at the perimeter of buildings, and at pavement edges adjacent to irrigated landscaped areas. A “plug” can consist of a 5-foot long section of clayey soils with more than 35- percent passing the No. 200 sieve, or a Controlled Low Strength Material Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
(CLSM) consisting of one sack of Portland-cement plus one sack of bentonite per cubic-yard of sand. CLSM should generally conform to Section 201-6 of the “Greenbook”. This is intended to reduce the likelihood of water permeating trenches from landscaped areas, then seeping along permeable trench backfill into the building and pavement subgrades, resulting in wetting of moisture sensitive subgrade earth materials under buildings and pavements.
Excavation of utility trenches should be performed in accordance with the project plans, specifications and the California Construction Safety Orders (current Edition). The contractor should be responsible for providing a "competent person" as defined in Article 6 of the California Construction Safety Orders. Contractors should be advised that sandy soils (such as fills generated from the onsite alluvium) could mak e excavations particularly unsafe if all safety precautions are not properly implemented. In addition, excavations at or near the toe of slopes and/or parallel to slopes may be highly unstable due to the increased driving force and load on the trench wall. Spoil piles from the excavation(s) and construction equipment should be kept away from the sides of the trenches. Leighton does not consult in the area of safety engineering.
5.1.7 Drainage
All drainage should be directed away from structures, slopes and pavements by means of approved permanent/temporary drainage devices. Adequate storm drainage of any proposed pad should be provided to avoid wetting of foundation soils. Irrigation adjacent to buildings should be avoided when possible. As an option, sealed-bottom planter boxes and/or drought resistant vegetation should be used within 5-feet of buildings.
5.1.8 Slope Design and Construction
Based on our understanding and for planning purposes, all fill and cut slopes will be designed and constructed at 2:1 (horizontal:vertical and expected to be less than 10 feet in height. These slopes are considered grossly stable for static and pseudostatic conditions. For planning purposes, cut slopes should be constructed as replacement fill slopes due to the highly erosive nature of site soils. Future grading plans should be subject to further review and evaluation.
The outer portion of fill slopes should be either overbuilt by 2 feet (minimum) and trimmed back to the finished slope configuration or compacted in vertical increments of 5 feet (maximum) by a weighted sheepsfoot roller as the fill is placed. The slope face should then be track-walked by dozers of appropriate weight to achieve the final slope configuration and compaction to the slope face.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
Slope faces are inherently subject to erosion, particularly if exposed to wind, rainfall and irrigation. Landscaping and slope maintenance should be conducted as soon as possible in order to increase long-term surficial stability.
Berms should be provided at the top of fill slopes. Drainage should be directed such that surface runoff on the slope face is minimized.
5.2 Foundation Design
Based on our analysis, and upon implementat ion of remedial grading measures recommendations herein, the use of shallow isolated and/or continuous footings will be suitable to support the proposed residential structures.
5.2.1 Bearing and Lateral Pressures
The proposed foundations and slabs should be designed in accordance with the structural consultants’ design, the minimum recommendations presented herein, and the 2019 CBC. In utilizing the minimum geotechnical foundation recommendations, the structural consultant should design the foundation system to acceptable deflection criteria as determined by the architect. Foundation footings may be designed with the following geotechnical design parameters:
Bearing Capacity: A net allowable bearing capacity of 2,500 pounds per square foot (psf), or a modulus of subgrade reaction of 200 pci may be used for design of footings founded entirely into compacted fill. The footings should extend a minimum of 12 inches below lowest adjacent grade. A minimum base width of 18 inches for continuous footings and a minimum bearing area of 3 square feet (1.75 ft by 1.75 ft) for pad foundations should be used. Additionally, an increase of one-third may be applied when considering short-term live loads (e.g. seismic and wind). Passive Pressures: The passive earth pressure may be computed as an equivalent fluid having a density of 300 psf per foot of depth, to a maximum earth pressure of 3,000 pounds per square foot. A coefficient of friction between soil and concrete of 0.35 may be used with dead load forces. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third The footing width, depth, reinforcement, slab reinforcement, and the slab- on-grade thickness should be designed by the project structural consultant based on recommendations and soil characteristics indicated herein and the most recently adopted edition of the CBC.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
5.2.2 Settlement
The project civil engineer, structural engineer, and architect should consider the potential effects of both static settlement and dynamic settlement presented below.
Static Settlement:
Most of the static settlement of onsite soils is expected to be immediate or within 30 days following fill placement/foundations. A differential static settlement of 0.5 inch over a 30- foot span may be considered for design purposes.
Dynamic Settlement: Based on our analysis, we estimate total dynamic settlement is expected to be approximately 4 inches. Due to relatively uniform alluvium conditions, this settlement is expected to be global and differential settlement minimal or less than 1-inch over a 30-foot horizontal span.
5.2.3 Vapor Retarder
It has been a standard of care to install a moisture retarder underneath all slabs where moisture condensation is undesirable. Moisture vapor retarders may retard but not totally eliminate moisture vapor movement from the underlying soils up through the slabs. Moisture vapor transmission may be additionally reduced by use of concrete additives. Leighton does not practice in the field of moisture vapor transmission evaluation/mitigation. Therefore, we recommend that a qualified person/firm be engaged/consulted to evaluate the general and specific moisture vapor transmission pathways and any impacts to proposed construction elements. This person/firm should provide recommendations for mitigation of potential adverse impact of moisture vapor transmission on various components of the structure as deemed appropriate.
Howev
er, based on our experience, the standard of practice in Southern California has evolved over the last 15 to 20 years where an acceptable vapor retarder system includes a membrane (such as 10- mil thick or greater), underlain by a capillary break consisting of 4 inches of clean ½-inch-minimum gravel or 2 -inch sand layer (SE>30). The structural engineer/architect or concrete contractor often require a sand layer be placed over the membrane (typically 2-inch thick layer) to help in curing and reduction of curling of concrete. If such sand layer is placed on top of the membrane, the contractor should not allow the sand to become wet prior to concrete placement (e.g., sand should not be placed if rain is expected).
In conc
lusion, construction of the vapor barrier/retarder system is dependent on several variables which cannot all be evaluated and/or tested from a geotechnical standpoint. As such, the des ign of this system should be a design team/owner decision taking into consideration finish flooring materials and manufacture’s installation requirements of proposed membrane.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
Moreover, we recommend that the design team also follow ACI Committee 302 publication for “Guide for Concrete Slabs that Receive Moisture- Sensitive Flooring Materials” (ACI 302.2R-06) which includes a flow chart that assists in determining if a vapor barrier /retarder is required and where it is to be placed.
5.3 Temporary Excavation and Shoring Design
All temporary excavations for utility trenches, retaining walls, and foundations should be performed in accordance with project plans, specifications, and all OSHA requirements. Excavations 5 feet or deeper should be laid back or shored in accordance with OSHA requirements before personnel are allowed to enter. Site soils should be considered as Type C Soil per OSHA guidelines.
No su
rcharge loads should be permitted within a horizontal distance equal to the height of cut or 5 feet, whichever is greater from the top of the cut, unless the cut is shored appropriately. Excavations that extend below an imaginary plane inclined at 45 degrees below the edge of any adjacent existing site foundation should be properly shored to maintain support of the adjacent structure.
5.4 Preliminary Pavement Design Parameters
Our laboratory testing of a bulk soil sample collected from a depth of 0 to 5 feet bgs, yielded an R-value of 25. Pavement section recommendations based on this test are presented below in Table 4 . T he recommendations are intended for planning purposes only and should not supersede minimum City or County requirements. For final pavement design, appropriate traffic indices should be selected by the project civil engineer or traffic engineering consultant. Additional testing should be performed to verify design parameters once samples representative of finish soil subgrade material are confirmed and collectible.
Table 4. Pavement Section Design
Street Type
Loading
Conditions
TI
AC Pavement Section Thickness
Asphaltic-Concrete (AC)
Thickness (inch)
Aggregate Base (AB)
Thickness (inch)
Alleys/Local
Streets 5 3.0 6.0
Collector Street/
Truck Access 6 3.5 8.5
Perimeter
Roadways 7 4.0 10.5
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
The upper 6 inches of subgrade soil should be properly compacted to at least 95 percent relative compaction (ASTM D1557) and should be moisture- conditioned to near optimum and kept in this condition until the pavement section is constructed. Proof-rolling subgrade to identify localized areas of yielding subgrade (if any) should be performed prior to placement of aggregate base and under the observation of the geotechnical consultant.
Minimum relative compaction requirements for aggregate base should be 95 percent of the maximum laboratory density as determined by ASTM D1557. Base rock should conform to the "Standard Specifications for Public Works Construction" (green book) current edition or Caltrans Class 2 aggregate base having a minimum R -value of 78. Asphaltic concrete should be placed on compacted aggregate base and compacted to minimum 95% relative compaction.
The pavement sections provided in this section are intended as minimum values.
Should thinner or highly variable as -built pavement sections result from construction, increased maintenance and repair may be needed.
5.5 Retaining Walls
Retaining wall earth pressures are a function of the amount of wall yielding horizontally under load. If a wall can yield enough to mobilize full shear strength of backfill soils, then it can be designed for "a ctive" pressure. If a wall cannot yield under the applied load, the shear strength of the soil cannot be mobilized and the earth pressure will be higher. Such walls should be designed for "at rest" conditions.
If a structure moves toward the soils, the resulting resistance developed by the soil is the "passive" resistance. Retaining walls backfilled with non- expansive soils should be designed using the following equivalent fluid pressures:
Table 5. Retaining Wall Design Earth Pressures (Static, Drained) Loading
Conditions
Equivalent Fluid Density (pcf)
Level Backfill 2:1 Backfill
Active 33 50
At-Rest 50 80
Passive* 300 150 (2:1, sloping down)
* This assumes level condition in front of the wall will remain for the duration of the project, not to exceed 3,000 psf at depth. If sloping down (2:1) grades exist in front of walls, then they should be designed using passive values reduced to ½ of level backfill passive resistance values.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
Unrestrained (yielding) cantilever walls should be designed for the active equivalent-fluid weight value provided above for very low to low expansive soils that are free draining. In the design of walls restrained from movement at the top (non-yielding) such as basement or elevator pit/utility vaults, the at-rest equivalent fluid weight value should be used. Total depth of retained earth for design of cantilever walls should be measured as the vertical distance below the ground surface measured at the wall face for stem design, or measured at the heel of the footing for overturning and sliding calculations. Should a sloping backfill other than a 2:1 (horizontal:vertical) be constructed above the wall (or a backfill is loaded by an adjacent surcharge load), the equivalent fluid weight values provided above should be re- evaluated on an individual case basis by us. Non- standard wall designs should also be reviewed by us prior to construction to check that the proper soil parameters have been incorporated into the wall design.
All retaining walls should be provided with appropriate drainage. The outlet pipe should be sloped to drain to a suitable outlet. Typical wall drainage design is illustrated in Appendix E, Retaining Wall Backfill and Subdrain Detail. Wall backfill should be non-expansive (EI ≤ 21) sands compacted by mechanical methods to a minimum of 90 percent relative compaction (ASTM D 1557). Clayey site soils should not be used as wall backfill. Walls should not be backfilled until wall concrete attains the 28- day compressive strength and/or as determined by the Structural Engineer that the wall is structurally capable of supporting backfill.
Lightweight compaction equipment should be used, unless otherwise approved by the Structural Engineer.
5.6 Foundation Setback from Slopes
We recommend a minimum horizontal setback distance from the face of slopes for all structural footings (retaining and decorative walls, flatwork, building footings, pools, etc.). This distance is measured from the outside bottom edge of the footing horizontally to the slope face (or the face of a retaining wall) and should be a minimum of H/2, where H is the slope height (in feet).
Table 6. Footing Setbacks
Slope Height Recommended Footing Setback
<5 feet 5 feet minimum
5 to 15 feet 7 feet minimum
>15 feet H/2, where H is the slope height, not to exceed 10 feet to 2:1 slope face
*Per county minimum or as calculated
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
The soils within the structural setback area generally possess poor lateral stability and improvements (such as retaining walls, pools, sidewalks, fences, pavements, decorative flatwork, etc.) constructed within this setback area will be subject to lateral movement and/or differential settlement. Potential distress to such improvements may be mitigated by providing a deepened footing or a pier and grade-beam foundation system to support the improvement. The deepened footing should meet the setback described above. Modifications of slope inclinations near foundations may increase the setback and should be reviewed by the design team prior to completion of design or implementation.
5.7 Concrete Flatwork
Exterior concrete slabs-on-grade should have a minimum thickness of 4 inches.
Common Type II cement should be adequate for concrete flatwork not exposed to recycled water. Type V cement and a water:cement ratio of 0.45 should be used for c oncrete exposed to recycled water.
Concrete flatwork should be placed on compacted fill. If this material has been disturbed or become dry or desiccated, the subgrade soil should be moisture conditioned to near optimum moisture content and recompacted to a minimum of 90 percent relative compaction to a depth of 12 inches. Moisture content should be checked 48 hours prior to placing concrete.
As discussed in conjunction with floor slabs, minor cracking of concrete after curing due to expansion, drying and shrinkage is normal and should be expected.
However, cracking is often aggravated by a high water -to-cement ratio, high concrete temperature at the time of placement, small nominal aggregate size, and rapid moisture loss due to hot, dry, and/or windy weather conditions during placement and curing. Cracking due to temperature and moisture fluctuations can also be expected.
The use of low-slump concrete or low water/cement ratios can reduce the potential for shrinkage cracking. Inclusion of joints at frequent intervals and reinforcement will help control the locations of cracking, and improve aesthetics. Control joints should be spaced at regular intervals no greater than 6 feet on- center and have appropriate joints and saw cuts in accordance with either Portland Cement Association (PCA) or American Concrete Institute (ACI) guidelines . If cracking occurs, repairs may be needed to mitigate
a trip hazard (should it develop) and/or
improve the appearance.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
Landscape areas must be separated from pavements with concrete curbs and/or edge drains. Excessive over -irrigation will have an adverse effect on adjacent pavements. Irrigation adjacent to pavements, without a deep curb or other cutoff to separate landscaping from paving will result in premature pavement distress.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
6.0 GEOTECHNICAL CONSTRUCTION SERVICES
The long term integrity and performance of foundation and earthwork improvements for residential development projects is closely attributable to an adequate construction review process. Geotechnical review is of paramount importance as a part of this process. To verify that project grading and foundation plans conform to the recommendations of this report, we recommend Leighton professionals be retained to review these plan(s) once available.
Dire
ct observation and testing by the geotechnical professional during remedial grading and foundation construction allows for an assessment of exposed soil conditions and verification of the geotechnical conclusions and recommendations presented herein. Our presence also affords opportunity to provide alterative recommendations where/if warranted to address unanticipated conditions in the field. We therefore recommend that Leighton be retained during rough and precise grading earthwork to provide these services. Our geotechnical observation and testing services are typically required by the city for the following:
• Following compl etion of site demolition and clearing; • During ground preparation, subsur face excavation, and overexcavation of soils; • During compaction of all fill materials;
• Following foundati on excavation, prior to placement of any forms, steel or concrete; • During slab-on-grade, driveway and flatwork subgrade preparation, • During street, curb-gutter base placement and asphalt paving; • During utility trench bac kfilling and compaction; and • When any unusual conditions are encountered.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
7.0 LIMITATIONS
Leighton and Associates, Inc.’s work was performed using the degree of care and skill ordinarily exercised, under similar circumstances, by reputable geotechnical consultants practicing in California at this time. No other warranty, express or implied, is made as to the conclusions and professional opinions included in this report.
This
report is issued with the understanding that it is the responsibility of the owner or a duly authorized agent acting on behalf of the owner, to ensure that information and recommendations contained herein are brought to the attention of the necessary design consultants for this project and incorporated into plans and specifications.
The conc
lusions and preliminary recommendations in this report are based in part upon data that were obtained from a necessarily limited number of observations, site visi ts, excavations, samples and tests. Such information can be obtained only with respect to the specific locations explored, and therefore may not completely define all subsurface conditions throughout the site. The nature of many sites is that differing geotechnical and/or geological conditions can occur within small distances and under varying climatic conditions.
Furthermore, changes in subsurface conditions can and do occur over time. Therefore, the findings, conclusions, and recommendations presented in this report should be considered preliminary if unanticipated conditions are encountered and additional explorations, testing and analyses may be necessary to develop alternative recommendations.
Any
persons using this report for bidding or construction purposes should perform such independent investigations as they deem necessary to satisfy themselves as to the surface and/or subsurface conditions to be encountered and the procedures to be used in the performance of work on the subject site. For additional information about geotechnical engineering studies and this reports and its applicability, provided by the Geoprofessional Business Association (GBA), the client is referred to Appendix F, GBA Important Information About This Geotechnical Engineering Report.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
8.0 REFERENCES
Bean, Robert T., and others, 1959, Geology of San Jacinto and Elsinore Units, Appendix B, in Santa Ana River Investigations: California Department.
Bryant, W.A., and Hart, E.W., 2007, Fault-Rupture Hazard Zones in California, Alquist-Priolo Earthquake Fault Zoning Act with Index to Earthquake Zones Maps, Department of Conservation, California Geological Survey, Special Publication 42. 2007 Interim Revision.
California Building Code, (CBC) 2019, California Code of Regulations Title 24, Part 2, Volume 2 of 2.
California State Water Resources Control Board, 2016, GEOTRACKER, website:
http://geotracker.waterboards.ca.gov/
California, State of, Department of Conservation, Division of Mines and Geology (now CGS), 1994, Subsidence and Ground Fissures in the San Jacinto Basin Area, Southern California, Open-File Report, 94-532.
Campbell, Kenneth, W., 1996, Strong Motion Attenuation Relationships, in Seismic Hazards Analysis, AEG Short Course, Thomas F. Blake Program Coordinator, January 20, 1996.
Hutton, L. K., L. M. Jones, E. Hauksson, and D. D. Given, 1991, Seismotectonics of Southern California, in Neote ctonics of North America, D. B. Slemmons, E. R.
Engdahl, M. D. Zoback, and D. D. Blackwell (Editors), Geol. Soc. Am., Decade Map, VolI, Boulder, Colorado.
Lofgren, Ben E., and Rubin, Meyer, 1976, Land subsidence and aquifer -system compactions in the San Jacinto Valley, Riverside County, California —progress report: Journal Research vs. Geological Survey, Vol. 4 No 1.
Morton, D.M., 1977, Surface Deformation in Part of the San Jacinto Valley, Southern California, in Journal of Research, U.S.G.S., Vol 5, No. 1. _____, 2008, National Seismic Hazard Maps – Fault Parameters, http://
geohazards.usgs.gov/cfusion/hazfaults_2008_search/query_main.cfm.
OSHPD, 2022, Seismic Design Maps, an interactive computer program on OSHPD website to calculate Seismic Response and Design Parameters based on ASCE 7- 16 seismic procedures, https://seismicmaps.org/
Onderdonk, N., et.al, 2018, A 3,700 yr. paleoseismic record from northern San Jacinto fault and imprecations for joint rupture of the San Jacinto and San Andreas faults, dated October 2018, Geosphere.
Design-Level Geotechnical Exploration May 19, 2022
Proposed 50-Acre Residential Development, Moreno Valley, CA Project No. 13169.003
Public Works Standard, Inc., 2021, Greenbook, Standard Specifications for Public Works Construction: BNI Building News, Anaheim, California.
Riverside County, 2019, Safety Element, dated August 6.
Thatcher, W., and T. Hanks, 1973, Source parameters of Southern California Earthquakes, J. Geophysics. Res.78, 8547–8576.
United States Geological Survey, (USGS) Pasadena Office, California Earthquake History, 1769 to Present: www.pasadena.wr.usgs.gov/info/cahist_eqs.html. _____, 1971, Editors Jerry L. Coffman and Carl A von Hake, Earthquake History of the United States, in USGS Publication 41-1.
_____, 2005, Preliminary Geologic Map of the Hemet 7.5’ Quadrangle, Riverside County, California, Version 1.1, USGS OFR-2004-1455.
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SITE LOCATION MAP
50-Acre Residential Development Project
City of Moreno Valley
Riverside County, California
Approximate
Site Boundary
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FIGURE 1
Map Saved as J:\Drafting\13169\003\Maps\13169.003_F02_ELM_2022-03-21.mxd on 5/9/2022 12:57:13 PM Author: KVM (kmanchikanti)
GEOTECHNICAL MAP
50-Acre Residential Development Project
City of Moreno Valley
Riverside County, California
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³
0 2,000 4,000
Feet
Scale:1 " = 2,000 '
Project: 13169.003 Eng/Geol: JLH/SIS
Map Saved as J:\Drafting\13169\003\Maps\13169-003_F03_RGM_2022-03-21.mxd on 3/25/2022 1:59:21 PM Author: Leighton Geomatics (kmanchikanti) Date: March 2022
REGIONAL GEOLOGY MAP
50-Acre Residential Development Project
City of Moreno Valley
Riverside County, California
Approximate
Site Location
Geologic Units
Qvof, Very Old Alluvial Fan
Deposits
!!!
!! !
!
!
!
!
!!
!
!
Qya, Young Alluvial Valley
Deposits
Qyf, Young Alluvial Fan
Deposits
gr, Granitic and other intrusive
crystalline rocks of all ages
FIGURE 3
Reference: Copyright:© 2013 National Geographic
Society, i-cubed
Geology: Southern California Preliminary Geology by
³
0 4 8
Miles
Scale:1 " = 4 miles
Project: 13169.003 Eng/Geol: JLH/SIS
Map Saved as J:\Drafting\13169\003\Maps\13169-003_F04_RFM_2022-03-21.mxd on 3/25/2022 1:54:25 PM Author: Leighton Geomatics (kmanchikanti) Date: March 2022
REGIONAL FAULT MAP
50-Acre Residential Development Project
City of Moreno Valley
Riverside County, California
Approximate
Site Location
FIGURE 4
Legend
Fault activity
Recency of Movement
Historic (<200 years)
Holocene (<11,700 years)
Late Quaternary (last 700,000 years)
Quaternary (<1.6M years)
Basemap Reference: © 2022 Microsoft Corporation
Earthstar Geographics SIO © 2022 TomTom
Seismicity Data Reference: maps.conservation.ca.gov
?zE
!"`$
%&h(
³
0 2 4
Miles
Scale:1 " = 2 miles
Project: 13169.003 Eng/Geol: JLH
Map Saved as J:\Drafting\13169\003\Maps\13169-003_F05_LM_2022-03-21.mxd on 3/25/2022 2:18:10 PM Author: Leighton Geomatics (kmanchikanti) Date: March 2022
LIQUEFACTION MAP
50-Acre Residential Development Project
City of Moreno Valley
Riverside County, California
Approximate
Site Location
Legend
Liquefaction Susceptibility
High
Very High
Moderate
Low
Very low
FIGURE 5
Reference: Copyright:© 2013 National
Geographic Society, i-cubed
Liquefaction: Riverside County
?zE
³
0 2,000 4,000
Feet
Scale:1 " = 2,000 '
Project: 13169.003 Eng/Geol: JHL/SIS
Map Saved as J:\Drafting\13169\003\Maps\13169.003_F06_FHM_2022-03-21.mxd on 3/25/2022 2:23:06 PM Author: KVM (kmanchikanti) Date: March 2022
FLOOD HAZARD ZONE MAP
Approximate
Site Location
Reference: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
FEMA (http://www.fema.gov/index.shtm), DWR (http://www.dwr.ca.gov) Legend
100-Year Floodplains
500-Year Floodplains
50-Acre Residential Development Project
City of Moreno Valley
Riverside County, California
FIGURE 6
?zE
!"`$
%&h(
³
0 2 4
Miles
Scale:1 " = 2 miles
Project: 13169.003 Eng/Geol: JLH/SIS
Map Saved as J:\Drafting\13169\003\Maps\13169-003_F07_SM_2022-03-21.mxd on 3/25/2022 2:10:37 PM Author: Leighton Geomatics (kmanchikanti) Date: March 2022
SUBSIDENCE MAP
50-Acre Residential Development Project
City of Moreno Valley
Riverside County, California
Approximate
Site Location
Legend
Subsidence Susceptible
FIGURE 7
Service Layer Credits: Copyright:© 2013 National
Geographic Society, i-cubed
Subsidence Data: Riverside County
APPENDIX A
BORI
NG / TEST PIT / INFILTRATION TEST LOGS
4 3
3 2
2 3
3 7
13 9
12 14
4 5
6 5
10 11
3 4
5 112
108
122
SM
SP-SM
SM
SM
SP-SM
B-1
R-1
R-2
R-3
R-4
S-5
S-6
S-7
4 5
10 Undocumented Artificial Fill (Afu)
@0': Vegetation overlying tilled topsoil
Silty SAND with Gravel, yellow brown, predomantly fine-to-coarse sand, subrounded gravels, slightly moist
Quaternary Young Alluvial Fan Deposits (Qya)
@2.5': Silty SAND, brown, loose, predominantly fine to medium sand, trace coarse sand, micaceous, slightly moist
@5': Silty SAND, brown, loose, predominantly fine sand, trace medium to coarse sand, trace gravel, subrounded gravels up to
0.5 inch diameter, micaceous, slightly moist (CO = 6.2%) @7.5': Silty SAND, brown, medium dense, predominantly fine to medium sand, few subangular gravels, trace clay, micaceous @10': Poorly-graded SAND, yellow brown, medium dense,
predominantly fine and medium sand, some coarse sand, trace subrounded gravel, friable, micaceous, moist
@15': Silty SAND, yellow brown, medium dense, predominantly fine sand, trace coarse sand, trace clay, friable, very moist @20': Poorly-graded SAND, yellow brown, medium dense,
predominantly fine to medium sand, trace coarse sand, moist @21': Silty SAND, yellow brown, dense, predominantly fine sand, trace coarse sand, trace clay, friable, very moist
@25': Poorly-graded SAND, yellow brown, medium dense,
predominantly fine sand, some medium sand, trace coarse sand, trace rounded gravels, micaceous, moist
CO
Hole Diameter
Moisture
Ground Elevation
Depth
Blows
Elevation
Per 6 Inches
1630'
BULK SAMPLE
CORE SAMPLE
GRAB SAMPLE
RING SAMPLE
SPLIT SPOON SAMPLE
TUBE SAMPLE
B
C
G
R
S
T
LFO
CME-75 HSA Truck - 140lb - Autohammer - 30" Drop
Soil Class.
3-4-22
SOIL DESCRIPTION
Sampled By
Drilling Co.Drilling Co.
Project
Project No.
See Figure 2 - Geotechnical Map
Highpointe MV 1
13169.003
Drilling Method
8"
Sample No.
Feet
Attitudes
SAMPLE TYPES:
Martini Drilling
* * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Content, %
GEOTECHNICAL BORING LOG LB-1
Logged By
Date Drilled
LFO/YTN
Feet
S
(U.S.C.S.)
Log
Type of Tests
Graphic
pcf
Location
Dry Density
N
This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual.
TYPE OF TESTS:
-200
AL
CN
CO
CR
CU
% FINES PASSING
ATTERBERG LIMITS
CONSOLIDATION
COLLAPSE
CORROSION
UNDRAINED TRIAXIAL
DS
EI
H
MD
PP
RV
DIRECT SHEAR
EXPANSION INDEX
HYDROMETER
MAXIMUM DENSITY
POCKET PENETROMETER
R VALUE
SA
SE
SG
UC
SIEVE ANALYSIS
SAND EQUIVALENT
SPECIFIC GRAVITY
UNCONFINED COMPRESSIVE STRENGTH
1630
1625
1620
1615
1610
1605
1600
0 5
10 15
20 25
30 3
5 4
S-8 @30': Poorly-graded SAND, yellow brown, medium dense, predominantly fine sand, some medium sand, trace coarse sand, trace rounded gravels, micaceous, very moist
Total Depth: 31.5 feet bgs
No groundwater encountered during drilling
Boring backfilled with soil tailings
Hole Diameter
Moisture
Ground Elevation
Depth
Blows
Elevation
Per 6 Inches
1630'
BULK SAMPLE
CORE SAMPLE
GRAB SAMPLE
RING SAMPLE
SPLIT SPOON SAMPLE
TUBE SAMPLE
B
C
G
R
S
T
LFO
CME-75 HSA Truck - 140lb - Autohammer - 30" Drop
Soil Class.
3-4-22
SOIL DESCRIPTION
Sampled By
Drilling Co.Drilling Co.
Project
Project No.
See Figure 2 - Geotechnical Map
Highpointe MV 1
13169.003
Drilling Method
8"
Sample No.
Feet
Attitudes
SAMPLE TYPES:
Martini Drilling
* * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Content, %
GEOTECHNICAL BORING LOG LB-1
Logged By
Date Drilled
LFO/YTN
Feet
S
(U.S.C.S.)
Log
Type of Tests
Graphic
pcf
Location
Dry Density
N
This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual.
TYPE OF TESTS:
-200
AL
CN
CO
CR
CU
% FINES PASSING
ATTERBERG LIMITS
CONSOLIDATION
COLLAPSE
CORROSION
UNDRAINED TRIAXIAL
DS
EI
H
MD
PP
RV
DIRECT SHEAR
EXPANSION INDEX
HYDROMETER
MAXIMUM DENSITY
POCKET PENETROMETER
R VALUE
SA
SE
SG
UC
SIEVE ANALYSIS
SAND EQUIVALENT
SPECIFIC GRAVITY
UNCONFINED COMPRESSIVE STRENGTH
1600
159
5 1590
1585
1580
1575
1570
30 35
40 45
50 55
60 7
11 15
14 16
22 12
13 15
8 13
12 5
8 10
5 5
6 4
5 6
117
123
120
120
110
SM
B-1
R-1
R-2
R-3
R-4
R-5
S-6
S-7
4 6
7 7
11 Undocumented Artificial Fill (Afu)
@0': Vegetation overlying tilled topsoil
Silty SAND with Gravel, yellow brown, predominantly medium to coarse sand, slightly moist
Quaternary Very Old Alluvial Fan Deposits (Qvof)
@2.5': Silty SAND, yellow brown, medium dense, predominantly fine to medium sand, some coarse sand, trace granite gravels, slightly moist
@5': Silty SAND, brown, dense, predominantly fine to medium sand, some coarse sand, trace granite gravels, slightly micaceous, moist
@7.5': Silty SAND, yellow brown, medium dense, predominantly fine to medium sand, some coarse sand, slightly micaceous, moist @10': Silty SAND, yellow brown, medium dense, predominantly fine to medium sand, some coarse sand, trace subrounded gravel, micaceous, moist
@15': Silty SAND, yellow brown, medium dense, predominantly fine sand, some medium sand, micaceous, moist (CO = 2.2%)
@20': Silty SAND, yellow brown with gray mottling, medium dense, predominantly fine to medium sand, some coarse sand,
subrounded, micaceous, moist
@25': SAND with Silt, yellow brown, medium dense, predominantly fine to medium sand, some coarse sand, slightly micaceous, moist to very moist
-200, RV
CO
-200
Hole Diameter
Moisture
Ground Elevation
Depth
Blows
Elevation
Per 6 Inches
1617'
BULK SAMPLE
CORE SAMPLE
GRAB SAMPLE
RING SAMPLE
SPLIT SPOON SAMPLE
TUBE SAMPLE
B
C
G
R
S
T
LFO
CME-75 HSA Truck - 140lb - Autohammer - 30" Drop
Soil Class.
3-4-22
SOIL DESCRIPTION
Sampled By
Drilling Co.Drilling Co.
Project
Project No.
See Figure 2 - Geotechnical Map
Highpointe MV 1
13169.003
Drilling Method
8"
Sample No.
Feet
Attitudes
SAMPLE TYPES:
Martini Drilling
* * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Content, %
GEOTECHNICAL BORING LOG LB-2
Logged By
Date Drilled
LFO/YTN
Feet
S
(U.S.C.S.)
Log
Type of Tests
Graphic
pcf
Location
Dry Density
N
This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual.
TYPE OF TESTS:
-200
AL
CN
CO
CR
CU
% FINES PASSING
ATTERBERG LIMITS
CONSOLIDATION
COLLAPSE
CORROSION
UNDRAINED TRIAXIAL
DS
EI
H
MD
PP
RV
DIRECT SHEAR
EXPANSION INDEX
HYDROMETER
MAXIMUM DENSITY
POCKET PENETROMETER
R VALUE
SA
SE
SG
UC
SIEVE ANALYSIS
SAND EQUIVALENT
SPECIFIC GRAVITY
UNCONFINED COMPRESSIVE STRENGTH
1615
1610
1605
1600
1595
1590
0 5
10 15
20 25
30 3
3 5
SP-SMS-8 @30': SAND with Silt, yellow brown, medium dense, predominantly fine to medium sand, some coarse sand, slightly micaceous, moist to very moist
Total Depth: 31.5 feet bgs
No groundwater encountered during drilling
Boring backfilled with soil tailings
Hole Diameter
Moisture
Ground Elevation
Depth
Blows
Elevation
Per 6 Inches
1617'
BULK SAMPLE
CORE SAMPLE
GRAB SAMPLE
RING SAMPLE
SPLIT SPOON SAMPLE
TUBE SAMPLE
B
C
G
R
S
T
LFO
CME-75 HSA Truck - 140lb - Autohammer - 30" Drop
Soil Class.
3-4-22
SOIL DESCRIPTION
Sampled By
Drilling Co.Drilling Co.
Project
Project No.
See Figure 2 - Geotechnical Map
Highpointe MV 1
13169.003
Drilling Method
8"
Sample No.
Feet
Attitudes
SAMPLE TYPES:
Martini Drilling
* * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Content, %
GEOTECHNICAL BORING LOG LB-2
Logged By
Date Drilled
LFO/YTN
Feet
S
(U.S.C.S.)
Log
Type of Tests
Graphic
pcf
Location
Dry Density
N
This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual.
TYPE OF TESTS:
-200
AL
CN
CO
CR
CU
% FINES PASSING
ATTERBERG LIMITS
CONSOLIDATION
COLLAPSE
CORROSION
UNDRAINED TRIAXIAL
DS
EI
H
MD
PP
RV
DIRECT SHEAR
EXPANSION INDEX
HYDROMETER
MAXIMUM DENSITY
POCKET PENETROMETER
R VALUE
SA
SE
SG
UC
SIEVE ANALYSIS
SAND EQUIVALENT
SPECIFIC GRAVITY
UNCONFINED COMPRESSIVE STRENGTH
1585
1580
1575
1570
1565
1560
30 35
40 45
50 55
60 3
3 4
4 3
4 6
6 7
3 6
9 2
4 4
9 8
10 4
9 10
103
102
109
SM
SP-SM
B-1
R-1
R-2
R-3
R-4
S-5
S-6
S-7
4 4
6 Undocumented Artificial Fill (Afu)
@0': Vegetation overlying tilled topsoil
Silty SAND with Gravel, brown, predominantly fine to medium sand, some coarse sand, subrounded granitic gravel, slightly moist Quaternary Young Alluvial Fan Deposits (Qyf)
@2.5': Silty SAND, brown, loose, predominantly fine to medium sand, some coarse sand, trace subrounded gravel, slightly micaceous, slightly moist (MD = 133.2 @ 8.2%)
@5': Silty SAND, brown, loose, predominantly fine to medium sand, some coarse sand, trace subrounded gravel, slightly micaceous, moist
@7.5': Silty SAND, brown, medium dense, predominantly fine to medium sand, trace coarse sand, moist (CO = 3.8%)
@10': Silty SAND, brown, medium dense, predominantly fine to medium sand, trace coarse sand, micaceous, moist (CO = 4.6%) @15': Silty SAND, brown, medium dense, predominantly fine to medium sand, trace coarse sand, micaceous, moist
@20': SAND with Silt, brown, medium dense, predominantly fine to medium sand, some coarse sand, slightly micaceous, moist to very moist
@25': SAND with Silt, brown, medium dense, predominantly fine to medium sand, some coarse sand, micaceous, moist to very moist
CR, MD,
SA
CO
CO
Hole Diameter
Moisture
Ground Elevation
Depth
Blows
Elevation
Per 6 Inches
1599'
BULK SAMPLE
CORE SAMPLE
GRAB SAMPLE
RING SAMPLE
SPLIT SPOON SAMPLE
TUBE SAMPLE
B
C
G
R
S
T
LFO
CME-75 HSA Truck - 140lb - Autohammer - 30" Drop
Soil Class.
3-4-22
SOIL DESCRIPTION
Sampled By
Drilling Co.Drilling Co.
Project
Project No.
See Figure 2 - Geotechnical Map
Highpointe MV 1
13169.003
Drilling Method
8"
Sample No.
Feet
Attitudes
SAMPLE TYPES:
Martini Drilling
* * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Content, %
GEOTECHNICAL BORING LOG LB-3
Logged By
Date Drilled
LFO/YTN
Feet
S
(U.S.C.S.)
Log
Type of Tests
Graphic
pcf
Location
Dry Density
N
This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual.
TYPE OF TESTS:
-200
AL
CN
CO
CR
CU
% FINES PASSING
ATTERBERG LIMITS
CONSOLIDATION
COLLAPSE
CORROSION
UNDRAINED TRIAXIAL
DS
EI
H
MD
PP
RV
DIRECT SHEAR
EXPANSION INDEX
HYDROMETER
MAXIMUM DENSITY
POCKET PENETROMETER
R VALUE
SA
SE
SG
UC
SIEVE ANALYSIS
SAND EQUIVALENT
SPECIFIC GRAVITY
UNCONFINED COMPRESSIVE STRENGTH
1595
1590
1585
1580
1575
1570
0 5
10 15
20 25
30 4
6 6
SMS-8 @30': Silty SAND, brown, medium dense, predominantly fine to medium sand, some coarse sand, trace clay, trace subrounded gravel, moist
Total Depth: 31.5 feet bgs
No groundwater encountered during drilling
Boring backfilled with soil tailings
Hole Diameter
Moisture
Ground Elevation
Depth
Blows
Elevation
Per 6 Inches
1599'
BULK SAMPLE
CORE SAMPLE
GRAB SAMPLE
RING SAMPLE
SPLIT SPOON SAMPLE
TUBE SAMPLE
B
C
G
R
S
T
LFO
CME-75 HSA Truck - 140lb - Autohammer - 30" Drop
Soil Class.
3-4-22
SOIL DESCRIPTION
Sampled By
Drilling Co.Drilling Co.
Project
Project No.
See Figure 2 - Geotechnical Map
Highpointe MV 1
13169.003
Drilling Method
8"
Sample No.
Feet
Attitudes
SAMPLE TYPES:
Martini Drilling
* * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Content, %
GEOTECHNICAL BORING LOG LB-3
Logged By
Date Drilled
LFO/YTN
Feet
S
(U.S.C.S.)
Log
Type of Tests
Graphic
pcf
Location
Dry Density
N
This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual.
TYPE OF TESTS:
-200
AL
CN
CO
CR
CU
% FINES PASSING
ATTERBERG LIMITS
CONSOLIDATION
COLLAPSE
CORROSION
UNDRAINED TRIAXIAL
DS
EI
H
MD
PP
RV
DIRECT SHEAR
EXPANSION INDEX
HYDROMETER
MAXIMUM DENSITY
POCKET PENETROMETER
R VALUE
SA
SE
SG
UC
SIEVE ANALYSIS
SAND EQUIVALENT
SPECIFIC GRAVITY
UNCONFINED COMPRESSIVE STRENGTH
1565
1560
1555
1550
1545
1540
30 35
40 45
50 55
60 7
11 13
6 8
11 4
5 6
3 4
7 8
12 20
6 5
9 15
27 19
106
106
103
SM
SC-SM
SP-SM
B-1
R-1
R-2
R-3
R-4
R-5
S-6
R-7
5 5
8 Undocumented Artificial Fill (Afu)
@0': Vegetation overlying tilled topsoil
Silty SAND, light yellow brown, predominantly fine to medium sand, trace coarse sand, trace subangular gravel, slightly moist Quaternary Young Alluvial Fan Deposits (Qyf)
@2.5': Silty SAND, yellow brown, medium dense, predominantly fine sand, trace medium to coarse sand, slightly moist (MD = 130 @
8.5%)
@5': Silty SAND, yellow brown, medium dense, predominantly fine sand, trace medium to coarse sand, trace organic material, slightly micaceous, slightly moist
@7.5': Silty SAND, brown, loose, predominantly fine sand, trace medium to coarse sand, trace organic material, trace subrounded gravel, slightly micaceous, moist
@10': Silty SAND, brown, loose, predominantly fine to medium sand, some coarse sand, trace subangular gravel, trace clay, slightly micaceous, moist
Quaternary Very Old Alluvial Fan Deposits (Qvof)
@15': Silty Clayey SAND, reddish brown, dense, predominantly fine sand, trace gravel up to 1 inch diameter, low plasticity, moist @20': Poorly-graded SAND with Silt, orange brown, medium dense, predominantly fine to medium sand, trace coarse sand, trace subangular gravel, micaceous, slightly moist
@25': Poorly-graded SAND with Silt, reddish brown, dense, predominantly fine to medium sand, some coarse sand, some subangular gravel, moist
MD, SA
CO
-200
Hole Diameter
Moisture
Ground Elevation
Depth
Blows
Elevation
Per 6 Inches
1593'
BULK SAMPLE
CORE SAMPLE
GRAB SAMPLE
RING SAMPLE
SPLIT SPOON SAMPLE
TUBE SAMPLE
B
C
G
R
S
T
LFO
CME-75 HSA Truck - 140lb - Autohammer - 30" Drop
Soil Class.
3-4-22
SOIL DESCRIPTION
Sampled By
Drilling Co.Drilling Co.
Project
Project No.
See Figure 2 - Geotechnical Map
Highpointe MV 1
13169.003
Drilling Method
8"
Sample No.
Feet
Attitudes
SAMPLE TYPES:
Martini Drilling
* * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Content, %
GEOTECHNICAL BORING LOG LB-4
Logged By
Date Drilled
LFO/YTN
Feet
S
(U.S.C.S.)
Log
Type of Tests
Graphic
pcf
Location
Dry Density
N
This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual.
TYPE OF TESTS:
-200
AL
CN
CO
CR
CU
% FINES PASSING
ATTERBERG LIMITS
CONSOLIDATION
COLLAPSE
CORROSION
UNDRAINED TRIAXIAL
DS
EI
H
MD
PP
RV
DIRECT SHEAR
EXPANSION INDEX
HYDROMETER
MAXIMUM DENSITY
POCKET PENETROMETER
R VALUE
SA
SE
SG
UC
SIEVE ANALYSIS
SAND EQUIVALENT
SPECIFIC GRAVITY
UNCONFINED COMPRESSIVE STRENGTH
1590
1585
1580
1575
1570
1565
0 5
10 15
20 25
30 5
9 7
4 7
10 6
9 8
14 17
11 8
12 9
SM
SP-SM
SM
S-8
S-9
S-10
S-11
S-12
@30': Silty SAND, reddish brown, medium dense, predominantly fine sand, trace medium to coarse sand, trace clay, trace subangular gravel, micaceous, moist
@35': Silty SAND, reddish brown, medium dense, predominantly fine sand, trace medium to coarse sand, trace clay, trace subangular gravel, micaceous, moist
@40': Silty SAND, reddish brown, medium dense, predominantly fine sand, trace medium to coarse sand, trace clay, trace subangular gravel, micaceous, moist
@40.5': Pocket of gravel within Silty SAND
@45': Poorly-graded SAND, gray brown, dense, predominantly fine sand, some medium sand, trace coarse sand, trace clay, trace gravel, moist
@50': Silty SAND, reddish orange brown, dense, predominantly fine sand, some medium to coarse sand, micaceous, moist
Total Depth: 51.5 feet bgs
No groundwater encountered during drilling
Boring backfilled with soil tailings
Hole Diameter
Moisture
Ground Elevation
Depth
Blows
Elevation
Per 6 Inches
1593'
BULK SAMPLE
CORE SAMPLE
GRAB SAMPLE
RING SAMPLE
SPLIT SPOON SAMPLE
TUBE SAMPLE
B
C
G
R
S
T
LFO
CME-75 HSA Truck - 140lb - Autohammer - 30" Drop
Soil Class.
3-4-22
SOIL DESCRIPTION
Sampled By
Drilling Co.Drilling Co.
Project
Project No.
See Figure 2 - Geotechnical Map
Highpointe MV 1
13169.003
Drilling Method
8"
Sample No.
Feet
Attitudes
SAMPLE TYPES:
Martini Drilling
* * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Content, %
GEOTECHNICAL BORING LOG LB-4
Logged By
Date Drilled
LFO/YTN
Feet
S
(U.S.C.S.)
Log
Type of Tests
Graphic
pcf
Location
Dry Density
N
This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual.
TYPE OF TESTS:
-200
AL
CN
CO
CR
CU
% FINES PASSING
ATTERBERG LIMITS
CONSOLIDATION
COLLAPSE
CORROSION
UNDRAINED TRIAXIAL
DS
EI
H
MD
PP
RV
DIRECT SHEAR
EXPANSION INDEX
HYDROMETER
MAXIMUM DENSITY
POCKET PENETROMETER
R VALUE
SA
SE
SG
UC
SIEVE ANALYSIS
SAND EQUIVALENT
SPECIFIC GRAVITY
UNCONFINED COMPRESSIVE STRENGTH
1560
1555
1550
1545
1540
1535
30 35
40 45
50 55
60 6
9 11
5 6
8 SMR-1
R-2
B-1
Undocumented Artificial Fill (Afu)
@0': Vegetation overlying tilled topsoil
SAND with Silt, yellowbrown, predominantly fine to medium sand, some subangular gravel, organic material, slightly moist Quaternary Young Alluvial Fan Deposits (Qya)
@5': Silty SAND, brown, medium dense, predominantly fine sand, trace medium to coarse sand, slightly micaceous, slightly moist @10': Silty SAND, brown, medium dense, predominantly fine sand, trace coarse sand, moist (CO = 2.7%)
@12': Grades to Silty SAND with Gravel, reddish brown,
predominantly fine sand, moist
Total Depth: 13 feet bgs
No groundwater encountered during drilling
Boring converted to percolation test well with 0.020 slotted screen from 8 to 13 feet bgs
CO
-200
Hole Diameter
Moisture
Ground Elevation
Depth
Blows
Elevation
Per 6 Inches
1614'
BULK SAMPLE
CORE SAMPLE
GRAB SAMPLE
RING SAMPLE
SPLIT SPOON SAMPLE
TUBE SAMPLE
B
C
G
R
S
T
LFO
CME-75 HSA Truck - 140lb - Autohammer - 30" Drop
Soil Class.
3-4-22
SOIL DESCRIPTION
Sampled By
Drilling Co.Drilling Co.
Project
Project No.
See Figure 2 - Geotechnical Map
Highpointe MV 1
13169.003
Drilling Method
8"
Sample No.
Feet
Attitudes
SAMPLE TYPES:
Martini Drilling
* * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Content, %
GEOTECHNICAL BORING LOG LP-1
Logged By
Date Drilled
LFO/YTN
Feet
S
(U.S.C.S.)
Log
Type of Tests
Graphic
pcf
Location
Dry Density
N
This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual.
TYPE OF TESTS:
-200
AL
CN
CO
CR
CU
% FINES PASSING
ATTERBERG LIMITS
CONSOLIDATION
COLLAPSE
CORROSION
UNDRAINED TRIAXIAL
DS
EI
H
MD
PP
RV
DIRECT SHEAR
EXPANSION INDEX
HYDROMETER
MAXIMUM DENSITY
POCKET PENETROMETER
R VALUE
SA
SE
SG
UC
SIEVE ANALYSIS
SAND EQUIVALENT
SPECIFIC GRAVITY
UNCONFINED COMPRESSIVE STRENGTH
1610
1605
1600
1595
1590
1585
0 5
10 15
20 25
30 4
5 8
7 14
18 126
SM
SC-SM
B-1
R-1
B-1
R-2
10 Undocumented Artificial Fill (Afu)
@0': Vegetation overlying tilled topsoil
Silty SAND, dark brown, predominantly fine sand, trace medium sand, slightly moist
Quaternary Young Alluvial Fan Deposits (Qyf)
@0.5': Silty SAND, brown, predominantly fine sand, moist @5': Silty SAND, brown, medium dense, predominantly fine sand, trace coarse sand, trace rootlets, pinhole pores, slightly moist (CO = 9.3%)
Quaternary Very Old Alluvial Fan Deposits (Qvof)
@10': CLAY with Sand, reddish brown, medium dense,
predominantly fine sand, trace CaCO3 encrustation, slightly micaceous, low plasticity, moist
@11.5': Grades to Silty SAND with Gravel, brown, predominantly fine sand, trace coarse sand, rounded fine gravels, moist Total Depth: 13 feet bgs
No groundwater encountered during drilling
Boring converted to percolation test well with 0.020 slotted screen from 8 to 13 feet bgs
CO
-200
Hole Diameter
Moisture
Ground Elevation
Depth
Blows
Elevation
Per 6 Inches
1589'
BULK SAMPLE
CORE SAMPLE
GRAB SAMPLE
RING SAMPLE
SPLIT SPOON SAMPLE
TUBE SAMPLE
B
C
G
R
S
T
LFO
CME-75 HSA Truck - 140lb - Autohammer - 30" Drop
Soil Class.
3-4-22
SOIL DESCRIPTION
Sampled By
Drilling Co.Drilling Co.
Project
Project No.
See Figure 2 - Geotechnical Map
Highpointe MV 1
13169.003
Drilling Method
8"
Sample No.
Feet
Attitudes
SAMPLE TYPES:
Martini Drilling
* * * This log is a part of a report by Leighton and should not be used as a stand-alone document. * * * Content, %
GEOTECHNICAL BORING LOG LP-2
Logged By
Date Drilled
LFO/YTN
Feet
S
(U.S.C.S.)
Log
Type of Tests
Graphic
pcf
Location
Dry Density
N
This Soil Description applies only to a location of the exploration at the time of sampling. Subsurface conditions may differ at other locations and may change with time. The description is a simplification of the actual conditions encountered. Transitions between soil types may be gradual.
TYPE OF TESTS:
-200
AL
CN
CO
CR
CU
% FINES PASSING
ATTERBERG LIMITS
CONSOLIDATION
COLLAPSE
CORROSION
UNDRAINED TRIAXIAL
DS
EI
H
MD
PP
RV
DIRECT SHEAR
EXPANSION INDEX
HYDROMETER
MAXIMUM DENSITY
POCKET PENETROMETER
R VALUE
SA
SE
SG
UC
SIEVE ANALYSIS
SAND EQUIVALENT
SPECIFIC GRAVITY
UNCONFINED COMPRESSIVE STRENGTH
1585
1580
1575
1570
1565
1560
0 5
10 15
20 25
30 LOG OF TRENCH:
Project Name: Logged by: ),(/'ENGINEERING
PROPERTIESProject Number: Elevation:
Equipment: Location/Grid:
USCS
,Q6LWX
'HQVLW\
7HVW
1R
'HSWK
0RLVWXUH
'U\
'HQVLW\
/DE
7HVWVGEOLOGIC
ATTITUDES DATE: DESCRIPTION: GEOLOGIC
UNIT
GRAPHICAL REPRESENTATION:6RXWK:DOO SCALE: SURFACE SLOPE: TREND:
03.04.2022
1 inch = 2 feet East-West
TP-1
Highpointe MV 50 EMH
13169.003 Approx. 1625 ft
Backhoe See Figure2-G e o t e c h n i c a lM a p
1) 0'-1': Tilled material/ surficial soil. Sandy SILT (ML), light brown, slightly moist, fine sand, abundant rootlets
2) 1'-5': Silty Clayey SAND w/ Gravel (SC), reddish brown, moist, hard, fine to medium sand w/ occasional coarse sand and sporadic fine gravel, massive, debris flow, low to medium plasticity. Backhoe operator indicates hard digging.
Afu
Qvof
ML
SC BB-1
(1'-5')
LOG OF TRENCH:
Project Name: Logged by: ),(/'ENGINEERING
PROPERTIESProject Number: Elevation:
Equipment: Location/Grid:
USCS
,Q6LWX
'HQVLW\
7HVW
1R
'HSWK
0RLVWXUH
'U\
'HQVLW\
/DE
7HVWVGEOLOGIC
ATTITUDES DATE: DESCRIPTION: GEOLOGIC
UNIT
GRAPHICAL REPRESENTATION:East :DOO SCALE: SURFACE SLOPE: TREND:
03.04.2022
1 inch = 2 feet North-South
TP-2
Highpointe MV 50 EMH
13169.003 Approx. 1624 ft
Backhoe See Figure2-G e o t e c h n i c a lM a p
1) 0'-2': Tilled/ Loose Surficial Material: Silty SAND (SM), light brown, slightly moist, fine to medium sand w/ pockets of fine to coarse sand and fine gravel
2) 2'-5': Silty SAND (SM), light brown to light reddish brown, slightly moist, mostly fine to medium sand, few coarse sand and sporadic fine gravel, reverse graded, little clay
Afu
Qyf
SM
SM BB-1
(2'-5')
LOG OF TRENCH:
Project Name: Logged by: ),(/'ENGINEERING
PROPERTIESProject Number: Elevation:
Equipment: Location/Grid:
USCS
,Q6LWX
'HQVLW\
7HVW
1R
'HSWK
0RLVWXUH
'U\
'HQVLW\
/DE
7HVWVGEOLOGIC
ATTITUDES DATE: DESCRIPTION: GEOLOGIC
UNIT
GRAPHICAL REPRESENTATION:6RXWK:DOO SCALE: SURFACE SLOPE: TREND:
03.04.2022
1 inch = 2 feet East-West
TP-3
Highpointe MV 50 EMH
13169.003 Approx. 1609 ft
Backhoe See Figure2-G e o t e c h n i c a lM a p
1) 0'-8": Loose Surficial Soil: Silty SAND (SM), light brown, slightly moist, fine to medium sand, trace coarse sand and fine gravel, abundant rootlets
2) 8"-4.5': Clayey Sandy SILT (ML), reddish brown, slightly moist, fine to coarse sand w/ occasional fine gravel, massive, debris flow chaotic assemblage, low plasticity
Afu
Qyf
SM
ML BB-1
(1'-4.5')
LOG OF TRENCH:
Project Name: Logged by: ),(/'ENGINEERING
PROPERTIESProject Number: Elevation:
Equipment: Location/Grid:
USCS
,Q6LWX
'HQVLW\
7HVW
1R
'HSWK
0RLVWXUH
'U\
'HQVLW\
/DE
7HVWVGEOLOGIC
ATTITUDES DATE: DESCRIPTION: GEOLOGIC
UNIT
GRAPHICAL REPRESENTATION:(DVW:DOO SCALE: SURFACE SLOPE: TREND:
03.04.2022
1 inch = 2 feet North-South
TP-5
Highpointe MV 50 EMH
13169.003 Approx. 1595 ft
Backhoe See Figure2-G e o t e c h n i c a lM a p
1) 0'-1': Tilled Material: Silty SAND (SM), light brown, slightly moist, fine to medium sand, trace coarse sand and gravel
2) 1'-5': Silty SAND (SM), light brown to light reddish brown, slightly moist to moist, mostly fine to medium sand, with coarse sand and fine gravel, mostly massive w/ occasional faint laminations, trace clay binder Afu
Qyf
SM
SM BB-1
(3'-5')
Project Number: 13169.003 Test Hole Number: LP-1
Project Name: Highpoint MV 50 Date Excavated:
Earth Description: Alluvium Date Tested:
Liquid Description: Tap water Depth of boring (ft): 13
Tested By: LFO Radius of boring (in): 4
Time Interval Standard Radius of casing (in): 1
Start Time for Pre-Soak: 11:15 AM Length of slotted of casing (ft): 5 Start Time for Standard: 11:15 AM Depth to Initial Water Depth (ft): 8 25 mins Porosity of Annulus Material, n : 0.35
10 Bentonite Plug at Bottom: No
Reading Time Time Interval,
Δt (min.)
Initial/Final
Depth to
Water (ft.)
Initial/Final
Water Height,
H0/Hf
(in.)
Total Water
Drop, Δd (in.)
Infiltration
Rate (in./hr.)
11:17 9.25 45.0
11:42 11.30 20.4
11:51 9.85 37.8
12:16 11.51 17.9
12:44 10.00 36.0
12:54 10.75 27.0
12:55 9.81 38.3
13:05 10.53 29.6
13:06 10.05 35.4
13:16 10.95 24.6
13:20 9.95 36.6
13:30 10.65 28.2
13:32 10.07 35.2
13:44 10.99 24.1
13:50 9.95 36.6
14:00 10.76 26.9
Measured Infiltration Rate, I (Average of Last 3 Readings) = 1.29 in./hr.
P1 25 24.6 1.33
1.58 1.26
Standard Time Interval
Between Readings, mins:
Field Percolation Data - Falling Head Test
2 10 8.6 1.13
P2 25 19.9 1.25
Boring Percolation Test Data Sheet
3/14/2021
3/15/2021
1 10 9.0
3 10 10.8
11.0 1.36
4 10 8.4 1.14
Infiltration Rate (I) = Discharge Volume/Surface Area of Test Section/Time Interval 6 10 9.7 1.35
5 12
Project Number: 13169.003 Test Hole Number: LP-2
Project Name: Highpoint MV 50 Date Excavated:
Earth Description: Alluvium Date Tested:
Liquid Description: Tap water Depth of boring (ft): 13
Tested By: LFO Radius of boring (in): 4
Time Interval Standard Radius of casing (in): 1
Start Time for Pre-Soak: 10:21 AM Length of slotted of casing (ft): 5 Start Time for Standard: 10:21 AM Depth to Initial Water Depth (ft): 8 25 mins Porosity of Annulus Material, n : 0.35
30 Bentonite Plug at Bottom: No
Reading Time Time Interval,
Δt (min.)
Initial/Final
Depth to
Water (ft.)
Initial/Final
Water Height,
H0/Hf
(in.)
Total Water
Drop, Δd (in.)
Infiltration
Rate (in./hr.)
10:21 10.01 35.9
10:46 10.24 33.1
10:48 9.72 39.4
11:12 9.80 38.4
11:27 9.90 37.2
11:57 9.98 36.2
12:02 9.90 37.2
12:32 10.01 35.9
12:33 10.01 35.9
13:03 10.29 32.5
13:08 9.96 36.5
13:38 10.19 33.7
13:40 9.96 36.5
14:10 10.11 34.7
14:13 10.01 35.9
14:43 10.15 34.2
14:45 10.00 36.0
15:15 10.17 34.0
15:17 9.99 36.1
15:47 10.16 34.1
15:49 9.98 36.2
16:19 10.13 34.4
16:20 10.00 36.0
16:50 10.16 34.1
16:51 10.00 36.0
17:21 10.15 34.2
17:22 9.99 36.1
17:52 10.15 34.2
Measured Infiltration Rate, I (Average of Last 3 Readings) = 0.08 in./hr.
Infiltration Rate (I) = Discharge Volume/Surface Area of Test Section/Time Interval 12 30 1.9 0.08
11 30 1.8 0.08
10 30 1.9 0.08
7 8
9 30
30 30
0.09 0.09
0.08 2.0
5 30 1.8 0.07
4 30 2.8 0.12
3 30 3.4 0.15
2 30 1.3 0.05
1 30 1.0 0.04
25 1.0 0.04
2.0 1.8
Boring Percolation Test Data Sheet
3/14/2021
3/15/2021
6 30 1.7 0.07
Standard Time Interval
Between Readings, mins:
Field Percolation Data - Falling Head Test
P1 25 2.8 0.14
P2
APPENDIX B
LABORATORY TEST RESULTS
200 Wash (03-15-22)
LB-2 LB-2 LB-4 LP-1 LP-2
B-1 S-6 S-10 B-1 B-2
0 - 5.0 20.0 40.0 10.0 - 13.0 10.0 - 13.0
Bulk SPT SPT Bulk Bulk
10 10 10 10 10
595.4 524.9 543.2 528.1 539.9
579.6 511.1 529.9 518.0 531.9
277.3 329.2 332.7 327.9 420.9
5.2 7.6 6.7 5.3 7.2
A W A1 F S
579.6 511.1 529.9 518.0 531.9
277.3 329.2 332.7 327.9 420.9
302.3 181.9 197.2 190.1 111.0
A W A1 F S
484.5 466.9 476.3 445.1 486.9
277.3 329.2 332.7 327.9 420.9
207.2 137.7 143.6 117.2 66.0
31 24 27 38 41
69 76 73 62 59
Project Name:
Project No.:
Client Name:
Tested By: M. Vinet Date: 03/22/22
Wet Weight of Soil + Container (gm.)
Container No.:
Weight of Sample + Container (gm.)
Sample Dry Weight Determination
Depth (ft.)
Moisture Correction
Sample Type
Soil Classification
Soak Time (min)
After Wash
Boring No.
Sample No.
Container No.:
Weight of Container (gm)
Moisture Content (%)
Weight of Container (gm.)
Weight of Dry Sample (gm.)
% Passing No. 200 Sieve
Dry Weight of Soil + Container (gm.)
SM
PERCENT PASSING
No. 200 SIEVE
ASTM D 1140
SM SM SM
% Retained No. 200 Sieve
Dry Weight of Sample (gm)
Dry Weight of Sample + Container (gm)
Weight of Container (gm)
Highpointe MV 1 Geo
13169.003
Highpointe Communities
SM
Project Name: Tested By: M. Vinet Date: 3/21/22
Project No.: Checked By: M. Vinet Date: 3/23/22
Boring No.: LB-1 Sample Type: IN SITU
Sample No.: R-2 Depth (ft.) 5.0
Sample Description:
Source and Type of Water Used for Inundation: Arrowhead ( Distilled ) ** Note: Loading After Wetting (Inundation) not Performed Using this Test Method.
Initial Dry Density (pcf): 99.6 Final Dry Density (pcf): 109.3 Initial Moisture (%): 6.9 Final Moisture (%) : 14.9
Initial Height (in.): 1.0000 Initial Void ratio: 0.6932 Initial Dial Reading (in): 0.0000 Specific Gravity (assumed): 2.70 Inside Diameter of Ring (in): 2.416 Initial Degree of Saturation (%): 27.0
1.050 0.9833 0.00 -1.67 -1.67
2.013 0.9705 0.00 -2.95 -2.95
H2O 0.9107 0.00 -8.93 -8.93
Rev. 01-10
Swell (+)
Settlement (-)
% of Sample
Thickness
One-Dimensional Swell or Settlement
Corrected
Deformation
(%)
Pressure (p)
(ksf)
0.6649
0.6432
Apparent
Thickness
(in)
Void Ratio
Highpointe MV 1 Geo
0.0167
0.0295
Final Reading
(in)
Load
Compliance
(%)
-6.16 Percent Swell / Settlement After Inundation =
(ASTM D 4546) -- Method 'B'
Potential of Cohesive Soils
0.54200.0893
Silty Sand (SM), Brown.
13169.003
-10.00
-9.00
-8.00
-7.00
-6.00
-5.00
-4.00
-3.00
-2.00
-1.00
0.00 0.010 0.100 1.000 10.000
Deformation %
Log Pressure (ksf)
Deformation % - Log Pressure Curve
Inundate With
Distilled Water
Project Name: Tested By: M. Vinet Date: 3/21/22
Project No.: Checked By: M. Vinet Date: 3/23/22
Boring No.: LB-2 Sample Type: IN SITU
Sample No.: R-5 Depth (ft.) 15.0
Sample Description:
Source and Type of Water Used for Inundation: Arrowhead ( Distilled ) ** Note: Loading After Wetting (Inundation) not Performed Using this Test Method.
Initial Dry Density (pcf): 105.7 Final Dry Density (pcf): 111.1 Initial Moisture (%): 10.3 Final Moisture (%) : 16.0
Initial Height (in.): 1.0000 Initial Void ratio: 0.5952 Initial Dial Reading (in): 0.0000 Specific Gravity (assumed): 2.70 Inside Diameter of Ring (in): 2.416 Initial Degree of Saturation (%): 46.5
1.050 0.9813 0.00 -1.87 -1.87
2.013 0.9725 0.00 -2.75 -2.75
H2O 0.9511 0.00 -4.89 -4.89
Rev. 01-10
Swell (+)
Settlement (-)
% of Sample
Thickness
One-Dimensional Swell or Settlement
Corrected
Deformation
(%)
Pressure (p)
(ksf)
0.5653
0.5513
Apparent
Thickness
(in)
Void Ratio
Highpointe MV 1 Geo
0.0187
0.0275
Final Reading
(in)
Load
Compliance
(%)
-2.20 Percent Swell / Settlement After Inundation =
(ASTM D 4546) -- Method 'B'
Potential of Cohesive Soils
0.51720.0489
Silty Sand (SM), Brown.
13169.003
-10.00
-9.00
-8.00
-7.00
-6.00
-5.00
-4.00
-3.00
-2.00
-1.00
0.00 0.010 0.100 1.000 10.000
Deformation %
Log Pressure (ksf)
Deformation % - Log Pressure Curve
Inundate With
Distilled Water
Project Name: Tested By: M. Vinet Date: 3/21/22
Project No.: Checked By: M. Vinet Date: 3/23/22
Boring No.: LB-3 Sample Type: IN SITU
Sample No.: R-3 Depth (ft.) 7.5
Sample Description:
Source and Type of Water Used for Inundation: Arrowhead ( Distilled ) ** Note: Loading After Wetting (Inundation) not Performed Using this Test Method.
Initial Dry Density (pcf): 99.3 Final Dry Density (pcf): 106.8 Initial Moisture (%): 8.9 Final Moisture (%) : 17.6
Initial Height (in.): 1.0000 Initial Void ratio: 0.6978 Initial Dial Reading (in): 0.0000 Specific Gravity (assumed): 2.70 Inside Diameter of Ring (in): 2.416 Initial Degree of Saturation (%): 34.4
1.050 0.9761 0.00 -2.39 -2.39
2.013 0.9662 0.00 -3.38 -3.38
H2O 0.9297 0.00 -7.03 -7.03
Rev. 01-10
Swell (+)
Settlement (-)
% of Sample
Thickness
One-Dimensional Swell or Settlement
Corrected
Deformation
(%)
Pressure (p)
(ksf)
0.6573
0.6405
Apparent
Thickness
(in)
Void Ratio
Highpointe MV 1 Geo
0.0239
0.0338
Final Reading
(in)
Load
Compliance
(%)
-3.78 Percent Swell / Settlement After Inundation =
(ASTM D 4546) -- Method 'B'
Potential of Cohesive Soils
0.57850.0703
Silty Sand (SM), Brown.
13169.003
-10.00
-9.00
-8.00
-7.00
-6.00
-5.00
-4.00
-3.00
-2.00
-1.00
0.00 0.010 0.100 1.000 10.000
Deformation %
Log Pressure (ksf)
Deformation % - Log Pressure Curve
Inundate With
Distilled Water
Project Name: Tested By: M. Vinet Date: 3/21/22
Project No.: Checked By: M. Vinet Date: 3/23/22
Boring No.: LB-3 Sample Type: IN SITU
Sample No.: R-4 Depth (ft.) 10.0
Sample Description:
Source and Type of Water Used for Inundation: Arrowhead ( Distilled ) ** Note: Loading After Wetting (Inundation) not Performed Using this Test Method.
Initial Dry Density (pcf): 100.1 Final Dry Density (pcf): 109.1 Initial Moisture (%): 5.4 Final Moisture (%) : 16.1
Initial Height (in.): 1.0000 Initial Void ratio: 0.6846 Initial Dial Reading (in): 0.0000 Specific Gravity (assumed): 2.70 Inside Diameter of Ring (in): 2.416 Initial Degree of Saturation (%): 21.3
1.050 0.9757 0.00 -2.43 -2.43
2.013 0.9609 0.00 -3.91 -3.91
H2O 0.9170 0.00 -8.30 -8.30
Rev. 01-10
Swell (+)
Settlement (-)
% of Sample
Thickness
One-Dimensional Swell or Settlement
Corrected
Deformation
(%)
Pressure (p)
(ksf)
0.6437
0.6187
Apparent
Thickness
(in)
Void Ratio
Highpointe MV 1 Geo
0.0243
0.0391
Final Reading
(in)
Load
Compliance
(%)
-4.57 Percent Swell / Settlement After Inundation =
(ASTM D 4546) -- Method 'B'
Potential of Cohesive Soils
0.54480.0830
Silty Sand (SM), Brown.
13169.003
-10.00
-9.00
-8.00
-7.00
-6.00
-5.00
-4.00
-3.00
-2.00
-1.00
0.00 0.010 0.100 1.000 10.000
Deformation %
Log Pressure (ksf)
Deformation % - Log Pressure Curve
Inundate With
Distilled Water
Project Name: Tested By: M. Vinet Date: 3/22/22
Project No.: Checked By: M. Vinet Date: 3/23/22
Boring No.: LB-4 Sample Type: IN SITU
Sample No.: R-3 Depth (ft.) 7.5
Sample Description:
Source and Type of Water Used for Inundation: Arrowhead ( Distilled ) ** Note: Loading After Wetting (Inundation) not Performed Using this Test Method.
Initial Dry Density (pcf): 87.3 Final Dry Density (pcf): 95.4 Initial Moisture (%): 7.4 Final Moisture (%) : 25.4
Initial Height (in.): 1.0000 Initial Void ratio: 0.9318 Initial Dial Reading (in): 0.0000 Specific Gravity (assumed): 2.70 Inside Diameter of Ring (in): 2.416 Initial Degree of Saturation (%): 21.5
1.050 0.9904 0.00 -0.96 -0.96
2.013 0.9800 0.00 -2.00 -2.00
H2O 0.9144 0.00 -8.56 -8.56
Rev. 01-10
Potential of Cohesive Soils
0.76650.0856
Silty Sand (SM), Brown.
13169.003
0.0200
Final Reading
(in)
Load
Compliance
(%)
-6.69 Percent Swell / Settlement After Inundation =
(ASTM D 4546) -- Method 'B'
Swell (+)
Settlement (-)
% of Sample
Thickness
One-Dimensional Swell or Settlement
Corrected
Deformation
(%)
Pressure (p)
(ksf)
0.9133
0.8932
Apparent
Thickness
(in)
Void Ratio
Highpointe MV 1 Geo
0.0096
-10.00
-9.00
-8.00
-7.00
-6.00
-5.00
-4.00
-3.00
-2.00
-1.00
0.00 0.010 0.100 1.000 10.000
Deformation %
Log Pressure (ksf)
Deformation % - Log Pressure Curve
Inundate With
Distilled Water
Project Name: Tested By: M. Vinet Date: 3/22/22
Project No.: Checked By: M. Vinet Date: 3/23/22
Boring No.: LP-1 Sample Type: IN SITU
Sample No.: R-2 Depth (ft.) 10.0
Sample Description:
Source and Type of Water Used for Inundation: Arrowhead ( Distilled ) ** Note: Loading After Wetting (Inundation) not Performed Using this Test Method.
Initial Dry Density (pcf): 100.6 Final Dry Density (pcf): 106.0 Initial Moisture (%): 9.3 Final Moisture (%) : 19.1
Initial Height (in.): 1.0000 Initial Void ratio: 0.6750 Initial Dial Reading (in): 0.0000 Specific Gravity (assumed): 2.70 Inside Diameter of Ring (in): 2.416 Initial Degree of Saturation (%): 37.3
1.050 0.9863 0.00 -1.37 -1.37
2.013 0.9765 0.00 -2.35 -2.35
H2O 0.9497 0.00 -5.03 -5.03
Rev. 01-10
Potential of Cohesive Soils
0.59070.0503
Silty Sand (SM), Brown.
13169.003
0.0235
Final Reading
(in)
Load
Compliance
(%)
-2.74 Percent Swell / Settlement After Inundation =
(ASTM D 4546) -- Method 'B'
Swell (+)
Settlement (-)
% of Sample
Thickness
One-Dimensional Swell or Settlement
Corrected
Deformation
(%)
Pressure (p)
(ksf)
0.6520
0.6356
Apparent
Thickness
(in)
Void Ratio
Highpointe MV 1 Geo
0.0137
-10.00
-9.00
-8.00
-7.00
-6.00
-5.00
-4.00
-3.00
-2.00
-1.00
0.00 0.010 0.100 1.000 10.000
Deformation %
Log Pressure (ksf)
Deformation % - Log Pressure Curve
Inundate With
Distilled Water
Project Name: Tested By: M. Vinet Date: 3/22/22
Project No.: Checked By: M. Vinet Date: 3/23/22
Boring No.: LP-2 Sample Type: IN SITU
Sample No.: R-1 Depth (ft.) 5.0
Sample Description:
Source and Type of Water Used for Inundation: Arrowhead ( Distilled ) ** Note: Loading After Wetting (Inundation) not Performed Using this Test Method.
Initial Dry Density (pcf): 97.4 Final Dry Density (pcf): 110.1 Initial Moisture (%): 5.5 Final Moisture (%) : 16.8
Initial Height (in.): 1.0000 Initial Void ratio: 0.7307 Initial Dial Reading (in): 0.0000 Specific Gravity (assumed): 2.70 Inside Diameter of Ring (in): 2.416 Initial Degree of Saturation (%): 20.5
1.050 0.9843 0.00 -1.57 -1.57
2.013 0.9748 0.00 -2.52 -2.52
H2O 0.8845 0.00 -11.55 -11.55
Rev. 01-10
Potential of Cohesive Soils
0.53080.1155
Silty Sand (SM), Brown.
13169.003
0.0252
Final Reading
(in)
Load
Compliance
(%)
-9.26 Percent Swell / Settlement After Inundation =
(ASTM D 4546) -- Method 'B'
Swell (+)
Settlement (-)
% of Sample
Thickness
One-Dimensional Swell or Settlement
Corrected
Deformation
(%)
Pressure (p)
(ksf)
0.7036
0.6871
Apparent
Thickness
(in)
Void Ratio
Highpointe MV 1 Geo
0.0157
-15.00
-14.00
-13.00
-12.00
-11.00
-10.00
-9.00
-8.00
-7.00
-6.00
-5.00
-4.00
-3.00
-2.00
-1.00
0.00 0.010 0.100 1.000 10.000
Deformation %
Log Pressure (ksf)
Deformation % - Log Pressure Curve
Inundate With
Distilled Water
Compaction; LB-3, B-1 (03-15-22)
Tested By: F. Mina Date: 03/22/22
Input By: M. Vinet Date: 03/23/22
LB-3 Depth (ft.): 0 - 5.0
X Moist Mechanical Ram
Dry Manual Ram
Mold Volume (ft³) 0.03340 Ram Weight = 10 lb.; Drop = 18 in. 1 2 3 4 5 6
5523 5643 5722 5670
3539 3539 3539 3539
1984 2104 2183 2131
2129.7 1522.3 1602.7 1422.8
2071.9 1448.4 1502.7 1316.2
716.2 277.4 280.3 276.2
4.3 6.3 8.2 10.3
131.0 138.9 144.1 140.7
125.6 130.6 133.2 127.6
133.2 8.2
PROCEDURE USED
X Procedure A
Soil Passing No. 4 (4.75 mm) Sieve
Mold : 4 in. (101.6 mm) diameter
Layers : 5 (Five)
Blows per layer : 25 (twenty-five)
May be used if +#4 is 20% or less
Procedure B
Soil Passing 3/8 in. (9.5 mm) Sieve
Mold : 4 in. (101.6 mm) diameter
Layers : 5 (Five)
Blows per layer : 25 (twenty-five)
Use if +#4 is >20% and +3/8 in. is
20% or less
Procedure C
Soil Passing 3/4 in. (19.0 mm) Sieve
Mold : 6 in. (152.4 mm) diameter
Layers : 5 (Five)
Blows per layer : 56 (fifty-six)
Use if +3/8 in. is >20% and +¾ in.
is <30%
Particle-Size Distribution:
3:65:32
GR:SA:FI
Atterberg Limits:
LL,PL,PI
Optimum Moisture Content (%) Maximum Dry Density (pcf) Net Weight of Soil (g)
Wet Density (pcf)
Dry Density (pcf)
Moisture Content (%)
Wet Weight of Soil + Cont. (g)
Dry Weight of Soil + Cont. (g)
Weight of Container (g)
Weight of Mold (g)
Preparation Method:
Wt. Compacted Soil + Mold (g)
B-1
13169.003
TEST NO.
Soil Identification:
Sample No.:
Silty Sand (SM), Brown.
MODIFIED PROCTOR COMPACTION TEST
ASTM D 1557
Project No.:
Boring No.:
Highpointe MV 1 GeoProject Name:
120.0
125.0
130.0
135.0
140.0
0.0 5.0 10.0 15.0 20.
Dry Density (pcf)
Moisture Content (%)
SP. GR. = 2.75
SP. GR. = 2.80
SP. GR. = 2.85
XX
Compaction; LB-4, B-1 (03-15-22)
Tested By: F. Mina Date: 03/22/22
Input By: M. Vinet Date: 03/23/22
LB-4 Depth (ft.): 0 - 5.0
X Moist Mechanical Ram
Dry Manual Ram
Mold Volume (ft³) 0.03340 Ram Weight = 10 lb.; Drop = 18 in. 1 2 3 4 5 6
5576 5663 5684 5600
3539 3539 3539 3539
2037 2124 2145 2061
1289.2 1352.4 1399.2 1236.2
1231.3 1272.4 1296.4 1133.7
280.1 277.8 277.0 276.4
6.1 8.0 10.1 12.0
134.5 140.2 141.6 136.0
126.7 129.8 128.6 121.5
130.0 8.5
PROCEDURE USED
X Procedure A
Soil Passing No. 4 (4.75 mm) Sieve
Mold : 4 in. (101.6 mm) diameter
Layers : 5 (Five)
Blows per layer : 25 (twenty-five)
May be used if +#4 is 20% or less
Procedure B
Soil Passing 3/8 in. (9.5 mm) Sieve
Mold : 4 in. (101.6 mm) diameter
Layers : 5 (Five)
Blows per layer : 25 (twenty-five)
Use if +#4 is >20% and +3/8 in. is
20% or less
Procedure C
Soil Passing 3/4 in. (19.0 mm) Sieve
Mold : 6 in. (152.4 mm) diameter
Layers : 5 (Five)
Blows per layer : 56 (fifty-six)
Use if +3/8 in. is >20% and +¾ in.
is <30%
Particle-Size Distribution:
2:52:46
GR:SA:FI
Atterberg Limits:
LL,PL,PI
Optimum Moisture Content (%) Maximum Dry Density (pcf) Net Weight of Soil (g)
Wet Density (pcf)
Dry Density (pcf)
Moisture Content (%)
Wet Weight of Soil + Cont. (g)
Dry Weight of Soil + Cont. (g)
Weight of Container (g)
Weight of Mold (g)
Preparation Method:
Wt. Compacted Soil + Mold (g)
B-1
13169.003
TEST NO.
Soil Identification:
Sample No.:
Silty Sand (SM), Brown.
MODIFIED PROCTOR COMPACTION TEST
ASTM D 1557
Project No.:
Boring No.:
Highpointe MV 1 GeoProject Name:
115.0
120.0
125.0
130.0
135.0
0.0 5.0 10.0 15.0 20.
Dry Density (pcf)
Moisture Content (%)
SP. GR. = 2.75
SP. GR. = 2.80
SP. GR. = 2.85
XX
Project Name: Highpointe MV 1 Geo Tested By : M. Vinet Date: 03/23/22 Project No. : 13169.003 Data Input By: M. Vinet Date: 03/23/22 Boring No. LB-3
Sample No. B-1
Sample Depth (ft) 0 - 5.0
100.00
100.00
0.00 0.00
100.00
1 1
850
Timer
45 25.0362
25.0328
0.0034
139.91
140
ml of Extract For Titration (B) 30
ml of AgNO3 Soln. Used in Titration (C) 0.4
PPM of Chloride (C -0.2) * 100 * 30 / B 20
PPM of Chloride, Dry Wt. Basis 20
7.40 21.0
pH TEST, DOT California Test 643
TESTS for SULFATE CONTENT
CHLORIDE CONTENT and pH of SOILS
SULFATE CONTENT, DOT California Test 417, Part II
Soil Identification:
Moisture Content (%)
Temperature °C
pH Value
Silty Sand (SM)
Wt. of Crucible + Residue (g)
Dry Weight of Soil + Container (g)
Weight of Container (g)
Duration of Combustion (min)
Wet Weight of Soil + Container (g)
Wt. of Residue (g) (A)
Beaker No.
Crucible No.
Furnace Temperature (°C)
Time In / Time Out
Weight of Soaked Soil (g)
PPM of Sulfate, Dry Weight Basis
PPM of Sulfate (A) x 41150
CHLORIDE CONTENT, DOT California Test 422
Wt. of Crucible (g)
Project Name: Tested By : M. Vinet Date:
Project No. : Data Input By: M. Vinet Date:
Boring No.: Depth (ft.) :
Sample No. :
Soil Identification:*
*California Test 643 requires soil specimens to consist only of portions of samples passing through the No. 8 US Standard Sieve before resistivity testing. Therefore, this test method may not be representative for coarser materials.
Wt. of Container (g)10.00 8000
0.00 100.00
Moisture Content (%) (MCi)
Wet Wt. of Soil + Cont. (g)
Specimen
No.
1 2
Water
Added (ml)
(Wa)
50 Adjusted
Moisture
Content
(MC) Dry Wt. of Soil + Cont. (g)
8000
1.000
Chloride Content
(ohm-cm)
29.80 Moisture Content Sulfate Content
5 Min. Resistivity
DOT CA Test 643DOT CA Test 417 Part II DOT CA Test 422
(%) (ppm) (ppm)
DOT CA Test 643
4 83
116
149
A
500.003 290023.20
3700
2900 23.2 140 20 7.40 21.0
SOIL RESISTIVITY TEST
DOT CA TEST 643
Temp. (°C)pH
Soil pH
3700
2900
100.00
0.00 MC =(((1+Mci/100)x(Wa/Wt+1))-1)x100
Highpointe MV 1 Geo 03/23/22
03/23/22
0 - 5.0
13169.003
LB-3
B-1
Container No.
Initial Soil Wt. (g) (Wt)
Box Constant3100 3100
Silty Sand (SM)
Resistance
Reading
(ohm)
16.60 Soil
Resistivity
(ohm-cm)
0 1000
2000
3000
4000
5000
6000
7000
8000
9000
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0
Soil Resistivity (ohm-cm)
Moisture Content (%)
Minimum resistivity
read here
Project Name: Date: 3/22/22
Project Number: 13169.003 Technician: F. Mina
Boring Number: LB-2 Depth (ft.): 0 - 5.0
Sample Number: B-1 Sample Location: N/A
Sample Description: Silty Sand (SM), Brown.
TEST SPECIMEN A B C
MOISTURE AT COMPACTION % 7.9 8.4 9.4
HEIGHT OF SAMPLE, Inches 2.48 2.48 2.55
DRY DENSITY, pcf 122.3 121.3 120.2
COMPACTOR AIR PRESSURE, psi 215 200 175
EXUDATION PRESSURE, psi 646 441 286
EXPANSION, Inches x 10exp-4 0 0 0
STABILITY Ph 2,000 lbs (160 psi) 33 48 105
TURNS DISPLACEMENT 4.50 4.75 4.90
R-VALUE UNCORRECTED 68 55 21
R-VALUE CORRECTED 68 55 21
DESIGN CALCULATION DATA a b c
GRAVEL EQUIVALENT FACTOR 1.0 1.0 1.0
TRAFFIC INDEX 5.0 5.0 5.0
STABILOMETER THICKNESS, ft. 0.51 0.72 1.26
EXPANSION PRESSURE THICKNESS, ft. 0.00 0.00 0.00
EXPANSION PRESSURE CHART EXUDATION PRESSURE CHART R-VALUE BY EXPANSION: N/A
R-VALUE BY EXUDATION: 25
EQUILIBRIUM R-VALUE: 25
R-VALUE TEST RESULTS
ASTM D 2844
Highpointe MV 1 Geo
0.00 0.50
1.00 1.50
2.00 2.50
3.00 3.50
4.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00
COVER THICKNESS BY EXPANSION in
feet
COVER THICKNESS BY STABILOMETER in
feet
0 10
20 30
40 50
60 70
80 90
0100200300400500600700800
R-VALUE
EXUDATION PRESSURE (psi)
Project Name: Tested By: MRV Date: 03/23/22
Project No.: 13169.003 Checked By: MRV Date: 03/23/22
Boring No.: LB-3 Depth (feet): 0 - 5.0
Sample No.: B-1
Soil Identification: Silty Sand (SM), Brown.
Whole Sample Sample Passing
#4 Whole Sample Sample
passing #4
P P Wt. of Air-Dry Soil + Cont.(g) 2129.7 1020.5
2189.7 1020.5 Wt. of Dry Soil + Cont. (g) 2071.9 1020.5 716.2 716.2 Wt. of Container No._____(g) 716.2 716.2
1412.8 304.3 Moisture Content (%) 4.3 0.0
P
930.2
716.2
214.0
(mm.)
1 1/2"
1"
3/4"
1/2"
3/8"
#4
#8
#16
#30
#50
#100
#200
GRAVEL: 3 %
SAND: 65 %
FINES: 32 %
GROUP SYMBOL: SM N/A
N/A
Remarks:
204.6
44.1 74.0
114.2
162.6
0.075
PAN
0.0 12.7
39.34.750
2.360
1.180
0.600
0.300
0.150
Passing #4 Material After Wet Sieve
37.500
U. S. Sieve Size
25.000
19.000
12.500
9.500
Whole Sample
99.1 100.0
97.2 91.9
31.8 100.0
60.7 45.3
Wt. Air-Dried Soil + Cont.(g)
100.0
Cumulative Weight of Dry Soil Retained (g)
Sample Passing #4
PARTICLE-SIZE DISTRIBUTION (GRADATION)
ASTM D 6913
Container No.:
Highpointe MV 1 Geo
Moisture ContentsCalculation of Dry Weights
of SOILS USING SIEVE ANALYSIS
Dry Wt. of Soil (g)
Wt. of Container (g)
Container No.
100.0
83.1 73.6
Percent Passing
(%)
Wt. of Dry Soil + Container (g)
Wt. of Container (g)
Dry Wt. of Soil Retained on # 200 Sieve (g)
16.6 Cu = D60/D10 =
Cc = (D30)²/(D60*D10) =
3 : 65 : 32
B-1
Mar-22
Boring No.:
Depth (feet): 0 - 5.0 Soil Type :
Project Name:
PARTICLE - SIZE
DISTRIBUTION
ASTM D 6913
Soil Identification: Silty Sand (SM), Brown.
SM
GR:SA:FI : (%)
Highpointe MV 1 Geo
Project No.:
LB-3 Sample No.:
13169.003
SAND
SILT FINE
HYDROMETER
3.0" 1 1/2" 3/4" 3/8" #4 #8 #16 #30 #50 #100 #200 U.S. STANDARD SIEVE OPENING U.S. STANDARD SIEVE NUMBER
GRAVEL FINES
FINE CLAY COARSE COARSE MEDIUM
0 10
20 30
40 50
60 70
80 90
100
0.0010.0100.1001.00010.000100.000
PERCENT FINER BY WEIGHT
PARTICLE - SIZE (mm)
"
Sieve; LB-3, B-1 (03-15-22)
Project Name: Tested By: MRV Date: 03/23/22
Project No.: 13169.003 Checked By: MRV Date: 03/23/22
Boring No.: LB-4 Depth (feet): 0 - 5.0
Sample No.: B-1
Soil Identification: Silty Sand (SM), Brown.
B 1107.5
1107.5 1090.5
673.2 673.2
417.3 4.1
B
916.5
673.2
243.3
(in.) (mm.)
3" 75.000
1" 25.000
3/4" 19.000
1/2" 12.500
3/8" 9.500
#4 4.750
#8 2.360
#16 1.180
#30 0.600
#50 0.300
#100 0.150
#200 0.075
GRAVEL: 2 %
SAND: 52 %
FINES: 46 %
GROUP SYMBOL: SM N/A
N/A
Remarks:
226.6
70.6 45.7
173.5 58.4
After Wet Sieve Wt. of Dry Soil + Container (g)
Wt. of Container (g)
Dry Wt. of Soil Retained on # 200 Sieve (g)
100.0
97.8 Wt. of Dry Soil + Cont. (g)
87.6 94.722.3
100.0
51.9 Dry Wt. of Soil (g)
Cu = D60/D10 =
Cc = (D30)²/(D60*D10) =
0.0 9.2
PAN
122.5
Moisture Content of Total Air - Dry Soil
80.2 Wt. of Container No._____ (g)
Container No.
Percent Passing (%)
Wt. of Air-Dry Soil + Cont. (g)
82.5 100.0
100.0
Wt. of Air-Dried Soil + Cont.(g)
Moisture Content (%)
100.0
Wt. of Container (g)
U. S. Sieve Size Cumulative Weight
Dry Soil Retained (g)
PARTICLE-SIZE DISTRIBUTION (GRADATION)
ASTM D 6913
Container No.:
Highpointe MV 1 Geo
of SOILS USING SIEVE ANALYSIS
3.0" 1 1/2" 3/4" 3/8" #4 #8 #16 #30 #50 #100 #200 U.S. STANDARD SIEVE OPENING U.S. STANDARD SIEVE NUMBER
GRAVEL FINES
FINE CLAY COARSE COARSE MEDIUM
13169.003
SAND
SILT FINE
HYDROMETER
Highpointe MV 1 Geo
Project No.:
LB-4 Sample No.:
Soil Type :
PARTICLE - SIZE
DISTRIBUTION
ASTM D 6913
Soil Identification: Silty Sand (SM), Brown.
SM
GR:SA:FI : (%)
Boring No.:
Depth (feet): 0 - 5.0
Project Name:
B-1
Mar-222 : 52 : 46
0 10
20 30
40 50
60 70
80 90
100
0.0010.0100.1001.00010.000100.000
PERCENT FINER BY WEIGHT
PARTICLE - SIZE (mm)
"
Sieve; LB-4, B-1 (03-15-22)
APPENDIX C
SEISMIC DESIGN DATA AND SETTLEMENT ANALYSES
MV-1
Latitude, Longitude: 33.9205, -117.1871
Date 5/13/2022, 12:24:08 PM
Design Code Reference Document ASCE7-16
Risk Category II
Site Class D - Stiff Soil
Type Value Description
SS 1.921 MCER ground motion. (for 0.2 second period)
S1 0.758 MCER ground motion. (for 1.0s period)
SMS 1.921 Site-modified spectral acceleration value
SM1 null -See Section 11.4.8 Site-modified spectral acceleration value SDS 1.281 Numeric seismic design value at 0.2 second SA SD1 null -See Section 11.4.8 Numeric seismic design value at 1.0 second SA Type Value Description
SDC null -See Section 11.4.8 Seismic design category
Fa 1 Site amplification factor at 0.2 second
Fv null -See Section 11.4.8 Site amplification factor at 1.0 second PGA 0.811 MCEG peak ground acceleration
FPGA 1.1 Site amplification factor at PGA
PGAM 0.892 Site modified peak ground acceleration
TL 8 Long-period transition period in seconds
SsRT 1.99 Probabilistic risk-targeted ground motion. (0.2 second) SsUH 2.187 Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration SsD 1.921 Factored deterministic acceleration value. (0.2 second) S1RT 0.788 Probabilistic risk-targeted ground motion. (1.0 second) S1UH 0.886 Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration.
S1D 0.758 Factored deterministic acceleration value. (1.0 second) PGAd 0.811 Factored deterministic acceleration value. (Peak Ground Acceleration) CRS 0.91 Mapped value of the risk coefficient at short periods CR1 0.889 Mapped value of the risk coefficient at a period of 1 s Uni ed Hazard Tool
Input
U.S. Geological Survey - Earthquake Hazards Program
Please do not use this tool to obtain ground motion parameter values for the design code reference documents covered by the U.S. Seismic Design Maps web tools (e.g., the International Building Code and the ASCE 7 or 41 Standard). The values returned by the two applications are not identical.
Edition
Dynamic: Conterminous U.S. 2014 (update) (v4.2.0)
Latitude
Decimal degrees
33.9205
Longitude
Decimal degrees, negative values for western longitudes -117.1871
Site Class
360 m/s (C/D boundary)
Spectral Period
Peak Ground Acceleration
Time Horizon
Return period in years
2475
Hazard Curve
View Raw Data
Hazard Curves
Time Horizon 2475 years
Peak Ground Acceleration
0.10 Second Spectral Acceleration
0.20 Second Spectral Acceleration
0.30 Second Spectral Acceleration
0.50 Second Spectral Acceleration
0.75 Second Spectral Acceleration
1.00 Second Spectral Acceleration
2.00 Second Spectral Acceleration
3.00 Second Spectral Acceleration
4.00 Second Spectral Acceleration
5.00 Second Spectral Acceleration
1e-2 1e-1 1e+0
Ground Motion (g)
1e-9
1e-8
1e-7
1e-6
1e-5
1e-4
1e-3
1e-2
1e-1
1e+0
Annual Frequency of Exceedence
Uniform Hazard Response Spectrum
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
Spectral Period (s)
0.0 0.5
1.0 1.5
2.0 2.5
3.0 3.5
Ground Motion (g)
Spectral Period (s): PGA
Ground Motion (g): 0.9629
Component Curves for Peak Ground Acceleration
Time Horizon 2475 years
System
Grid
Interface
Fault
1e-2 1e-1 1e+0
Ground Motion (g)
1e-11
1e-10
1e-9
1e-8
1e-7
1e-6
1e-5
1e-4
1e-3
1e-2
1e-1
1e+0
Annual Frequency of Exceedence
Deaggregation
Component
Total
ε = (-∞ .. -2.5)
ε = [-2.5 .. -2)
ε = [-2 .. -1.5)
ε = [-1.5 .. -1)
ε = [-1 .. -0.5)
ε = [-0.5 .. 0)
ε = [0 .. 0.5)
ε = [0.5 .. 1)
ε = [1 .. 1.5)
ε = [1.5 .. 2)
ε = [2 .. 2.5)
ε = [2.5 .. +∞)
5 15
25 35
Closest Distance, rRup (km)
45 55
65 75
9 8.5
8 7.5
Magnitude (Mw)
7 6.5
6 5.5
5 4.5 5 10
% Contribution to Hazard
15 20 25 30
5 15
25 35
45 Closest Distance, rRup (km)
55 65
75 9
8.5 8
7.5 7
6.5 Magnitude (Mw)6
5.5 5
4.5 Summary statistics for, Deaggregation: Total
Deaggregation targets
Return period: 2475 yrs
Exceedance rate: 0.0004040404 yr⁻¹
PGA ground motion: 0.96286405 g
Recovered targets
Return period: 3094.6329 yrs
Exceedance rate: 0.00032314011 yr⁻¹
Totals
Binned: 100 %
Residual: 0 %
Trace: 0.06 %
Mean (over all sources)
m: 7.43
r: 7.54 km
ε₀: 1.43 σ
Mode (largest m-r bin)
m: 8.1
r: 4.93 km
ε₀: 1.09 σ
Contribution: 22.3 %
Mode (largest m-r-ε₀ bin)
m: 8.1
r: 4.86 km
ε₀: 0.96 σ
Contribution: 15.15 %
Discretization
r: min = 0.0, max = 1000.0, Δ = 20.0 km
m: min = 4.4, max = 9.4, Δ = 0.2
ε: min = -3.0, max = 3.0, Δ = 0.5 σ
Epsilon keys
ε0: [-∞ .. -2.5)
ε1: [-2.5 .. -2.0)
ε2: [-2.0 .. -1.5)
ε3: [-1.5 .. -1.0)
ε4: [-1.0 .. -0.5)
ε5: [-0.5 .. 0.0)
ε6: [0.0 .. 0.5)
ε7: [0.5 .. 1.0)
ε8: [1.0 .. 1.5)
ε9: [1.5 .. 2.0)
ε10: [2.0 .. 2.5)
ε11: [2.5 .. +∞]
Deaggregation Contributors
Source Set Source Type r m ε0 lon lat az %
UC33brAvg_FM31 System 38.31
San Jacinto (San Jacinto Valley) rev [1] 4.86 7.98 1.11 117.152°W 33.953°N 41.48 31.54 San Andreas (San Bernardino S) [2] 22.02 7.90 2.18 117.090°W 34.101°N 23.94 3.31 San Gorgonio Pass [2] 14.12 7.65 1.91 117.064°W 33.995°N 53.94 1.05 UC33brAvg_FM32 System 38.25
San Jacinto (San Jacinto Valley) rev [1] 4.86 7.97 1.11 117.152°W 33.953°N 41.48 31.50 San Andreas (San Bernardino S) [2] 22.02 7.90 2.18 117.090°W 34.101°N 23.94 3.34 UC33brAvg_FM31 (opt) Grid 11.72
PointSourceFinite: -117.187, 33.943 5.75 5.58 1.69 117.187°W 33.943°N 0.00 3.23 PointSourceFinite: -117.187, 33.943 5.75 5.58 1.69 117.187°W 33.943°N 0.00 3.23 PointSourceFinite: -117.187, 33.997 9.48 5.75 2.23 117.187°W 33.997°N 0.00 1.51 PointSourceFinite: -117.187, 33.997 9.48 5.75 2.23 117.187°W 33.997°N 0.00 1.51 UC33brAvg_FM32 (opt) Grid 11.72
PointSourceFinite: -117.187, 33.943 5.75 5.58 1.69 117.187°W 33.943°N 0.00 3.23 PointSourceFinite: -117.187, 33.943 5.75 5.58 1.69 117.187°W 33.943°N 0.00 3.23 PointSourceFinite: -117.187, 33.997 9.48 5.75 2.23 117.187°W 33.997°N 0.00 1.51 PointSourceFinite: -117.187, 33.997 9.48 5.75 2.23 117.187°W 33.997°N 0.00 1.51
APPENDIX D
GENERAL EARTHWORK AND GRADING SPECIFICATIONS FOR
ROUGH GRADING
i
APPENDIX D
LEIGHTON AND ASSOCIATES, INC.
GENERAL EARTHWORK AND GRADING SPECIFICATIONS FOR ROUGH GRADING
TABLE OF CONTENTS
Section Appendix J Page
1.0 GENERAL ................................................................................................................. 1
1.1 Intent .............................................................................................................. 1
1.2 The Geotechnical Consultant of Record ......................................................... 1
1.3 The Earthwork Contractor .............................................................................. 2
2.0 PREPARATION OF AREAS TO BE FILLED ............................................................. 2
2.1 Clearing and Grubbing ................................................................................... 2
2.2 Processing...................................................................................................... 3
2.3 Overexcavation .............................................................................................. 3
2.4 Benching ........................................................................................................ 3
2.5 Evaluation/Acceptance of Fill Areas ............................................................... 4
3.0 FILL MATERIAL ........................................................................................................ 4
3.1 General .......................................................................................................... 4
3.2 Oversize ......................................................................................................... 4
3.3 Import ............................................................................................................. 4
4.0 FILL PLACEMENT AND COMPACTION ................................................................... 5
4.1 Fill Layers ....................................................................................................... 5
4.2 Fill Moisture Conditioning ............................................................................... 5
4.3 Compaction of Fill ........................................................................................... 5
4.4 Compaction of Fill Slopes ............................................................................... 5
4.5 Compaction Testing........................................................................................ 5
4.6 Frequency of Compaction Testing .................................................................. 6
4.7 Compaction Test Locations ............................................................................ 6
5.0 SUBDRAIN INSTALLATION ...................................................................................... 6
6.0 EXCAVATION ........................................................................................................... 6
7.0 TRENCH BACKFILLS ............................................................................................... 7
7.1 Safety ............................................................................................................. 7
7.2 Bedding and Backfill ....................................................................................... 7
7.3 Lift Thickness ................................................................................................. 7
7.4 Obser
vation and Testing ................................................................................ 7
ii
Attachments - Standard Details
A - Key
ing and Benching Rear of Text
B - Oversize Rock Disposal Rear of Text
C - Canyon Subdrains Rear of Text
D - Buttress or Replacement Fill Subdrains Rear of Text E - Transition Lot Fills and Side Hill Fills Rear of Text
LEIGHTON AND ASSOCIATES, INC.
General Earthwork and Grading Specifications
1 1.0 GENERAL
1.1 Intent
These General Earthwork and Grading Specifications are for the grading and earthwork shown on the approved grading plan(s) and/or indicated in the geotechnical report(s). These Specifications are a part of the recommendations contained in the geotechnical report(s). In case of conflict, the specific recommendations in the geotechnical report shall supersede these more general Specifications. Observations of the earthwork by the project Geotechnical Consultant during the course of grading may result in new or revised recommendations that could supersede these specifications or the recommendations in the geotechnical report(s).
1.2 The Geotechnical Consultant of Record
Prior to commencement of work, the owner shall employ the Geotechnical Consultant of Record (Geotechnical Consultant). The Geotechnical Consultants shall be responsible for reviewing the approved geotechnical report(s) and accepting the adequacy of the preliminary geotechnical findings, conclusions, and recommendations prior to the commencement of the grading.
Prior
to commencement of grading, the Geotechnical Consultant shall review the "work plan" prepared by the Earthwork Contractor (Contractor) and schedule sufficient personnel to perform the appropriate level of observation, mapping, and compaction testing.
During
the grading and earthwork operations, the Geotechnical Consultant shall observe, map, and document the subsurface exposures to verify the geotechnical design assumptions. If the observed conditions are found to be significantly different than the interpreted assumptions during the design phase, the Geotechnical Consultant shall inform the owner, recommend appropriate changes in design to accommodate the observed conditions, and notify the review agency where required. Subsurface areas to be geotechnically observed, mapped, elevations recorded, and/or tested include natural ground after it has been cleared for receiving fill but before fill is placed, bottoms of all "remedial removal" areas, all key bottoms, and benches made on sloping ground to receive fill.
The Geotec
hnical Consultant shall observe the moi sture-conditioning and processing of the subgrade and fill materials and perform relative compaction testing of fill to determine the attained level of compaction.
LEIGHTON AND ASSOCIATES, INC.
General Earthwork and Grading Specifications
2 The Geotechnical Consultant shall provide the test results to the owner and the Contractor on a routine and frequent basis.
1.3 The Earthwork Contractor
The Earthwork Contractor (Contractor) shall be qualified, experienced, and knowledgeable in earthwork logistics, preparation and processing of ground to receive fill, moisture- conditioning and processing of fill, and compacting fill. The Contractor shall review and accept the plans, geotechnical report(s), and these Specifications prior to commencement of grading. The Contractor shall be solely responsible for performing the grading in accordance with the plans and specifications.
The Cont
ractor shall prepare and submit to the owner and the
Geotechnical Consultant a work plan that indicates the sequence of earthwork grading, the number of "spreads" of work and the estimated quantities of daily earthwork contemplated for the site prior to commencement of grading. The Contractor shall inform the owner and the Geotechnical Consultant of changes in work schedules and updates to the work plan at least 24 hours in advance of such changes so that appropriate observations and tests can be planned and accomplished.
The Contractor shall not assume that the Geotechnical Consultant is aware of all grading operations.
The Cont
ractor shall have the sole responsibility to provide adequate equipment and m ethods to accomplish the earthwork in accordance with the applicable grading codes and agency ordinances, these Specifications, and the recommendations in the approved geotechnical report(s) and grading plan(s). If, in the opinion of the Geotechnical Consultant, unsatisfactory conditions, such as unsuitable soil, improper moisture condition, inadequate compaction, insufficient buttress key size, adverse weather, etc., are resulting in a quality of work less than required in these specifications, the Geotechnical Consultant shall reject the work and may recommend to the owner that construction be stopped until the conditions are rectified.
2.0 PREPARATION OF AREAS TO BE FILLED
2.1 Clearing and Grubbing
Vegetation, such as brush, grass, roots, and other delet erious material shall be sufficiently removed and properly disposed of in a method acceptable to the owner, governing agencies, and the Geotechnical Consultant.
LEIGHTON AND ASSOCIATES, INC.
General Earthwork and Grading Specifications
3 The Geotec hnical Consultant shall evaluate the extent of these removals depending on specific site conditions. Earth fill material shall not contain more than 1 percent of organic materials (by volume). No fill lift shall contain more than 5 percent of organic matter. Nesting of the organic materials shall not be allowed.
If potenti
ally hazardous materials are encountered, the Contractor shall stop work in the affected area, and a hazardous material specialist shall be informed immediately for proper evaluation and handling of these materials prior to continuing to work in that area.
As presen
tly defined by the State of California, most refined petroleum products (gasoline, diesel fuel, motor oil, grease, coolant, etc.) have chemical constituents that are considered to be hazardous waste. As such, the indiscriminate dumping or spillage of these fluids onto the ground may constitute a misdemeanor, punishable by fines and/or imprisonment, and shall not be allowed.
2.2 Processing
Existing ground that has been declared satisfactory for support of fill by the Geotechnical Consultant shall be scarified to a minimum depth of 6 inches. Existing ground that is not satisfactory shall be overexcavated as specified in the following section. Scarification shall continue until soils are broken down and free of large clay lumps or clods and the working surface is reasonably uniform, flat, and free of uneven features that would inhibit uniform compaction.
2.3 Overexcavation
In addition to removals and overexcavations recommended in the approved geotechnical report(s) and the grading plan, soft, loose, dry, saturated, spongy, organic -rich, highly fractured or otherwise unsuitable ground shall be overexcavated to competent ground as evaluated by the Geotechnical Consultant during grading.
2.4 Benching
Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical units), the ground shall be stepped or benched.
Please see the Standard Details for a graphic illustration. The lowest bench or key shall be a minimum of 15 feet wide and at least 2 feet deep, into competent material as evaluated by the Geotechnical Consultant.
Other benches shall be excavated a minimum height of 4 feet into competent material or as otherwise recommended by the Geotechnical
LEIGHTON AND ASSOCIATES, INC.
General Earthwork and Grading Specifications
4 Consultant. Fill placed on ground sloping flatter than 5:1 shall also be benched or otherwise overexcavated to provide a flat subgrade for the fill.
2.5 Evaluation/Acceptance of Fill Areas
All areas to receive fill, including removal and processed areas, key bottoms, and benches, shall be observed, mapped, elevations rec orded, and/or tested prior to being accepted by the Geotechnical Consultant as suitable to receive fill. The Contractor shall obtain a written acceptance from the Geotechnical Consultant prior to fill placement. A licensed surveyor shall provide the survey control for determining elevations of processed areas, keys, and benches.
3.0 FILL MATERIAL
3.1 General
Material to be used as fill shall be essentially free of organic matter and other deleterious substances evaluated and accepted by the Geotechnical Consultant prior to placement. Soils of poor quality, such as those with unacceptable gradation, high expansion potential, or low strength shall be placed in areas acceptable to the Geotechnical Consultant or mixed with other soils to achieve satisfactory fill material.
3.2 Oversize
Oversize material defined as rock, or other irreducible material with a maximum dimension greater than 8 inches, shall not be buried or placed in fill unless location, materials, and placement methods are specifically accepted by the Geotechnical Consultant. Placement operations shall be such that nesting of oversized material does not occur and such that oversize material is completely surrounded by compacted or densified fill.
Oversize material shall not be placed within 10 v ertical feet of finish grade or within 2 feet of future utilities or underground construction.
3.3 Import
If importing of fill material is required for grading, proposed import material shall meet the requirements of Section 3.1. The potential import sour ce shall be given to the Geotechnical Consultant at least 48 hours (2 working days) before importing begins so that its suitability can be determined and appropriate tests performed.
LEIGHTON AND ASSOCIATES, INC.
General Earthwork and Grading Specifications
5 4.0 FILL PLACEMENT AND COMPACTION
4.1 Fill Layers
Approved fill material shall be placed in areas prepared to receive fill (per Section 3.0) in near -horizontal layers not exceeding 8 inches in loose thickness. The Geotechnical Consultant may accept thicker layers if testing indicates the grading procedures can adequately compa ct the thicker layers. Each layer shall be spread evenly and mixed thoroughly to attain relative uniformity of material and moisture throughout.
4.2 Fill Moisture Conditioning
Fill soils shall be watered, dried back, blended, and/or mixed, as necessary to attain a relatively uniform moisture content at or slightly over optimum. Maximum density and optimum soil moisture content tests shall be performed in accordance with the American Society of Testing and Materials (ASTM Test Method D1557).
4.3 Compaction of Fill
After each layer has been moisture- conditioned, mixed, and evenly spread, it shall be uniformly compacted to not less than 90 percent of maximum dry density (ASTM Test Method D1557). Compaction equipment shall be adequately sized and be either specifically designed for soil compaction or of proven reliability to efficiently achieve the specified level of compaction with uniformity.
4.4 Compaction of Fill Slopes
In addition to normal compaction procedures specified above, compaction of slopes shall be accomplished by backrolling of slopes with sheepsfoot rollers at increments of 3 to 4 feet in fill elevation, or by other methods producing satisfactory results acceptable to the Geotechnical Consultant.
Upon completion of grading, relative compaction of the fill, out to the slope face, shall be at least 90 percent of maximum density per ASTM Test Method D1557.
4.5 Compaction Testing
Field-tests for moisture content and relative compaction of the fill soils shall be performed by the Geotechnical Consultant. Location and frequency of tests shall be at the Consultant's discretion based on field conditions encountered. Compaction test locations will not necessarily be selected on a random basis. Test locations shall be selected to verify adequacy of compaction levels in areas that are judged to be prone to
LEIGHTON AND ASSOCIATES, INC.
General Earthwork and Grading Specifications
6 inadequate compaction (such as close to slope faces and at the fill/bedrock benches).
4.6 Frequency of Compaction Testing
Tests shall be taken at intervals not exceeding 2 feet in vertical rise and/or 1,000 cubic yards of compacted fill soils embankment. In addition, as a guideline, at least one test shall be taken on slope faces for each 5,000 square feet of slope face and/or each 10 feet of vertical height of slope. The Contractor shall assure that fill construction is such that the testing schedule can be accomplished by the Geotechnical Consultant.
The Contractor shall stop or slow down the earthwork construction if these minimum standards are not met.
4.7 Compaction Test Locations
The Geotechni cal Consultant shall document the approximate elevation and horizontal coordinates of each test location. The Contractor shall coordinate with the project surveyor to assure that sufficient grade stakes are established so that the Geotechnical Consultant can determine the test locations with sufficient accuracy. At a minimum, two grade stakes within a horizontal distance of 100 feet and vertically less than 5 feet apart from potential test locations shall be provided.
5.0 SUBDRAIN INSTALLATION
Subdrain systems shall be installed in accordance with the approved geotechnical report(s), the grading plan, and the Standard Details. The Geotechnical Consultant may recommend additional subdrains and/or changes in subdrain extent, location, grade, or material de pending on conditions encountered during grading. All subdrains shall be surveyed by a land surveyor/civil engineer for line and grade after installation and prior to burial.
Sufficient time should be allowed by the Contractor for these surveys.
6.0 EXCAVATION
Excavations, as well as over -excavation for remedial purposes, shall be evaluated by the Geotechnical Consultant during grading. Remedial removal depths shown on geotechnical plans are estimates only. The actual extent of removal shall be determi ned by the Geotechnical Consultant based on the field evaluation of exposed conditions during grading. Where fill -over-cut slopes are to be graded, the cut portion of the slope shall be made, evaluated, and accepted by the Geotechnical Consultant prior to placement of materials for construction of the fill portion of the slope, unless otherwise recommended by the Geotechnical Consultant.
LEIGHTON AND ASSOCIATES, INC.
General Earthwork and Grading Specifications
7 7.0 TRENCH BACKFILLS
7.1 Safety
The Contractor shall follow all OSHA and Cal/OSHA requirements for safety of trench excavations.
7.2 Bedding and Backfill
All bedding and backfill of utility trenches shall be performed in accordance with the applicable provisions of Standard Specifications of Public Works Construction. Bedding material shall have a Sand Equivalent greater than 30 (SE>30). The bedding shall be placed to 1 foot over the top of the conduit and densified by jetting. Backfill shall be placed and densified to a minimum of 90 percent of relative compaction from 1 foot above the top of the conduit to the surface.
The Geotec
hnical Consultant shall test the trench backfill for relative compaction. At least one test should be made for every 300 feet of trench and 2 feet of fill.
7.3 Lift Thickness
Lift thickness of trench backfill shall not exceed those allowed in the Standard Specifications of Public Works Construction unless the Contractor can demonstrate to the Geotechnical Consultant that the fill lift can be compacted to the minimum relative compaction by his alternative equipment and method.
7.4 Observation and Testing
The jetting of the bedding around the conduits shall be observed by the Geotechnical Consultant.
FILL SLOPE
PROJECTED PLANE 1: 1
(HORIZONTAL: VERTICAL)
MAXIMUM FROM TOE
OF SLOPE TO
APPROVED GROUND
EXISTING
GROUND SURFACE
FILL-OVER-CUT SLOPE
-
CUT-OVER-ALL SLOPE
PROJECTED PLANE
1 TO 1 MAXIMUM
FROM TOE OF SLOPE
TO APPROVED GROUND
KEYING AND BENCHING
REMOVE
UNSUITABLE
MATERIAL
REMOVE
UNSUITABLE
MATERIAL
UT FACE SHALL BE
CONSTRUCTED PRIOR
TO FILL PLACEMENT
REMOVE
UNSUITABLE
MATERIAL
BENCHING SHALL BE DONE WHEN SLOPE'S
ANGLE IS EQUAL TO OR GREATER THAN 5: 1.
MINIMUM BENCH HEIGHT SHALL BE 4 FEET
AND MINIMUM FILL WIDTH SHALL BE 9 FEET.
GENERAL EARTHWORK AND GRADING
SPECIFICATIONS
STANDARD DETAILS A
�Leighton
FINISH GRADE
_ - - - - - - ·10•- - - - COMPACTEDFILL:._-_-_-_-_-_-_:
MIN. - - - - - - - - - - - - - - --------- �--------------- _-_-_-_-_-_ � - �----_-_-_-_-_-_-_-_-_ - --
-----7- ------ ------- � -------v------o.-------o---------- -----� ------- _-_ - _-_-__ /--_-_-_-_-_-_-_-_-_-_ - _-_-_-_-_-_-_-_-_-_----- · 7-----------------------------7-------- v
-----
u
------------ --- - ------ ----
- -_-_-_-_-,e_-_-_ o-_-_-_ -
- -
-
-
-
-
-
-
-
-
-
--: er---_-
- - 10·- - . -7"' - - - - 0 - I-a- - - - - - - - - - - - _-_-_-r:1J:N.:....
_
_
_
...-:_- - - _-_-_-_-_-__ 4'MIN. _ -t� _ 15'MIN._-
_.-l
-
-
-_- -
-------p 7=�----n*-------�-��------- -- ------ - ---------- -- ------ --- - - - -,,,,�- - - _-..::_-_-_OVERSIZE
--_-_-_-_-_-_-_ - - -
-
-
- - - - /"" - - - - _ _ _ _ WINDROW ___ _
�---7--------------
• Oversize rock is larger than 8 inches
in largest dimension.
• Backfill with approved soil jetted or
flooded in place to fill all the voids.
• Do not bury rock within 10 feet of
finish grade.
• Windrow of buried rock shall be
parallel to the finished slope face.
PROFILE ALONG WINDROW
SECTION A-A'
JETTED OR FLOODED
APPROVED SOIL
-_ ---------------- ----------------_ A' :-::::---::::-::::-::::-::::-::::-::::-::::-::::-::::-� --------_
JETTED OR FLOODED
APPROVED SOIL
�
l
.�
�----------------------.---------------.----------,!
OVERSIZE ROCK DISPOSAL
GENERAL EARTHWORK AND GRADING
SPECIFICATIONS
STANDARD DETAILS B
L_ ____________ _j_ ________ ____JL__ _____ ___J
�
I
a.
E
� g
Cl
a:
NATURAL
GROUND
/
�----------::::-::::-::::-::::-::::-::::-::::-::::-::::-::::-::::-::::-::::-::::-::::-::::-::::-::::-::::-::::-- -� "'�" ---��--------_:COMPACTED FILL:._-_-_---
�------ - -
TYPICAL
BENCHING
-----------------�---.----..o..._-_-�_-_-_-_-_-_�---_-�----,,......... ----�----------::::-::::-::::-::::-::::-::::-::::-::::0
SUBDRAIN
(See Alternates A and B)
FILTER MATERIAL
SUBDRAIN ALTERNATE A PERFORATED PIPE SURROUNDED
WITH FILTER MATERIAL FILTER MATERIAL SHALL BE CLASS 2 PERMEABLE MATERIAL PER STATE OF CALIFORNIA STANDARD SPECIFICATION, OR APPROVED ALTERNATE.
FILTER MATERIAL (9FT 3/FT) CLASS 2 GRADING AS FOLLOWS:
Sieve Size
1"
3/4"
3/8"
No.4
No.8
No. 30
No. 50
No.200
Percent Passing
100
90-100
40-100
25-40
18-33
5-15
0-7
0-3
SUBDRAIN ALTERNATE A-1 SUBDRAIN ALTERNATE A-2
ALTERNATE B-1
PERFORATED PIPE
6" 0 MIN.
SUBDRAIN ALTERNATE B
3/4" MAX. GRAVEL OR
APPROVED EQUIVALENT
(9FT 3 /FT)
ALTERNATE B-2
0 PERFORATED PIPE IS OPTIONAL PER
GOVERNING AGENCY'S REQUIREMENTS
DETAIL OF CANYON SUBDRAIN TERMINAL
DESIGN
FINISHED GRADE
10' MIN. BACKFILL
r- 15' MIN.---i---i--20' MIN.
5' MIN PERFORATED
6"0MIN.
· • 6"0 MIN.----i
I
NON-PERFORATED
FILTER FABRIC
(MIRAFI 140N OR
APPROVED EQUIVALENT)
�
t :g ·e
1------------------,,------------------------,------------g CANYON
SUBDRAIN
GENERAL EARTHWORK AND GRADING
SPECIFICATIONS a.
E
�gSTANDARD DETAILS C
L...-----------------''------------------------1--------------' c.:
I
.15' MIN�
I
�- ��,,,..-����
OUTLET PIPES
4"1> NON-PERFORATED PIPE,
100' MAX. O.C. HORIZONTALLY
30' MAX. O.C. VERTICALLY
,,,/ / I
/ �,---------J
,,,,,, / I
/ ,..r ,,, ., I
/ ·�
/// /� ,,, , I �
/ --2% MIN. �
�
BACKCUT
/I
/ /
,,,
\
/ I BENCHING
// \ /i ,,,// \ /�
1'± / \ ,-- _J
J (! �/ _ 2% MIN. \ Jo1
. 2% MIN. --- / I
SUBDRAIN ALTERNATE B
r•-----15' MIN.----·-1
KEY DEPTH KEY WIDTH
2' MIN.
SUBDRAIN ALTERNATE A POSillVE SEAL SHOULD BE PROVIDED ----....
AT THE JOINT
CAL TRANS CLASS 2
,,o���, ;rr��:,��:
���""MIN
OUTLET PIPE
(NON-PERFORATED)
3/4" ROCK (3FT.3/FT)-----
WRAPPED IN FILTER FABRIC
T-CONNECTION FROM
COLLECTION PIPE TO OUTLET PIPE
• SUBDRAIN INSTALLATION - Subdrain collector pipe shall be installed with perforations down or, unless otherwise designated by the geotechnical consultant. Outlet pipes shall be non-perforated pipe. The subdrain pipe shall have at least 8 perforations uniformly spaced per foot. Perforation shall •
•
be 1/4" to 1/2" if drilled holes are used. All subdrain pipes shall have a gradient at least 2% towards the outlet.
SUBDRAIN PIPE - Subdrain pipe shall be ASTM D2751, ASTM D1527 (Schedule 40) or SDR 23.5 ABS pipe or ASTM D3034 (Schedule 40) or SDR 23.5 PVC pipe.
All outlet pipe shall be placed in a trench and, after fill is placed above it, rodded to verify integrity.
FILTER FABRIC
(MIRAFI 140 OR
APPROVED
EQUIVALENT)
�
I
.ci
::,
"'1
1-----------------""T"'"------------------.--------------tl
BUTTRESS OR
REPLACEMENT FILL
GENERAL EARTHWORK AND GRADING
SPECIFICATIONS
STANDARD DETAILS D SUBDRAINS
� g
.__ _______________ _._ _______________ __._ _________ __,a:
OVERBURDEN
OR UNSUITABLE
MATERIAL
CUT-FILL TRANSITION LOT OVEREXCAVATION
REMOVE
UNSUITABLE
\. GROUND \_..- ----
SIDE HILL FILL FOR CUT PAD
OVEREXCAVATE
AND RECOMPACT
(REPLACEMENT FILL)
/
/
/
----
/
/
/
/
4' MIN. <'\(/'
NATURAL
GROUND
�__-
__----
/
/
/
/
/
FINISHED CUT PAD
L...=��.,......-.J.J-------- SEE STANDARD DETAIL FOR SUBDRAINS
WHEN REQUIRED BY GEOTECHNICAL CONSUL TANT
KEY
2'MIN. �
DEPTH UNWEATHERED BEDROCK OR MATERIAL APPROVED
BY THE GEOTECHNICAL CONSULTANT
�
t .!!!ii= 51
·� 1------------------------.---------------"T"""-------------1!!!
TRANSITION LOT FILLS
AND SIDE HILL FILLS
GENERAL EARTHWORK AND GRADING
SPECIFICATIONS
STANDARD DETAILS E
a.
E
�gLeighton
.__ ___________________ __,_ ______________ _.__ _________ ____.a:
APPENDIX E
RETAIN
ING WALL BACKFILL AND SUBDRAIN DETAIL
SLOPE
OR LEVEL
WEEP HOLE ·_:..������-PERMEABLE
--.....,.-=--_.., MATERIAL
SEE NOTE 2
PERMEABLE MATERIA L GRA DATION:
SIEVE SIZE
1-inch
3/4-inch
3/8-inch
No. 4
No. 8
No. 30
No. 50
No. 200
PERCENT PASSING
100
90-100
40-100
25-40
18-33
5-15
0-7
0-3
RETAINING WALL BACKFILL AND DRAINAGE NOTES:
• These are schematic sections, not to scale.
• Waterproofing
should be provided where
moisture passing through retaining walls is
undesirable. Waterproofing is not observed nor
inspected by Leighton Consulting, Inc.
• All subdrains should be installed with a drainage
gradient of at least 1 percent.
• Outlet portion of subdrains should be solid pipe
at least 4-inches in diameter, discharging into a
suitable disposal area designed by the project
Civil Engineer. Subdrain pipes should be
accessible for maintenance (with cleanouts, etc.).
(SEE GRADATION
AND NOTE 6)
4-INCH DIAMETER
PERFORATED PIPE
(SEE NOTE 3)
OR:
SLOPE
OR LEVEL
FILTER FABRIC
(SEE NOTE 4)
WEEP HOLE ......i�-------,r---- )'4 TO 112
SEE NOTE 2
NUMBERED NOTES KEYED TO FIGURE:
INCH DIAMETER GRAVEL
WRAPPED IN
FILTER FABRIC
4-INCH DIAMETER
PERFORATED PIPE
(SEE NOTE 3)
1. Backcuts: Safe backcuts, in accordance with the current California Construction Safety Orders (Article 6) are required behind retaining walls to allow for Leighton Consulting, Inc. personnel to view drainage installation and to test backfill. Site safety is the responsibility of the Contractor.
2. Foundation Bearing Surfaces: Leighton Consulting, Inc. personnel should observe foundation bearing surfaces before reinforcing steel is placed.
3. Perforated Pipes: Perforated drainpipes should be either ASTM D 1527 Acrylonitrile Butadiene Styrene (ABS) or ASTM D 1785 Polyvinyl Chloride (PVC) Schedule 40 for backfill less than 15 feet deep and Schedule 80 for deeper backfill, or approved equivalent as promulgated by the project Civil Engineer. Pipe should be installed with perforations down. Perforations should be 3/8-inch diameter placed 120° radially in two-rows at 3-inch on center (staggered). Slotted pipe can be used when backfill over the pipe is less-than 15feet deep.
4. Non-Woven Filter Fabric: Filter fabric should be Mirafi 140NC or equivalent, conforming to Section 213-5 (Table 213-5.2 (A) 90N) of the Standard Specifications For Public Works Construction (Green book, 2015 Edition or more current).
Weepholes: Weephole should be at least 3-inches in diameter and spaced no more than 10-feet on-center 5· horizontally, at the base of retaining walls where a perforated drainpipe with gravity discharge is not provided.
If exposure is permitted, weepholes should be located 12 inches above finished grade. If exposure is not permitted such as for walls adjacent to sidewalks, then a pipe under the sidewalk discharged through the curb face, or equivalent, should be provided. For basements, watertight vaults and/or reservoir walls, a proper subdrain outlet system should be provided without weepholes.
Permeable Material: At least one cubic-foot of permeable material or crushed rock should be placed per each 6· horizontal foot of wall. Crushed rock should be wrapped in filter fabric as discussed in Note 4 (Mirafi 140NC or equivalent), above.
Backfill: All retaining wall backfill soils should have an Expansion Index (El) <50 and should be compacted to
7. at least 90-percent of the AST M D 1557 laboratory maxim um density, with all backfill tested by Leighton Consulting, Inc.
Proj: 12622.002 Eng/Geol: JDH/GIM RETAINING WALL BACKFILL AND SUBDRAIN DETAIL Scale: NTS Date: February, 2020
Draned By: MAM Checked By· V:\ffiAFTlNG\1262:i'.001\CAD\2019- 12-02\12622·001_F07_RW_2019 -12 -03.DWG (12·03·1911 :29:39AM) PKltted bi: btran Tract 5989, Harvest at Limoneira Development
City of Santa Paula, California
Figure 2
APPE
NDIX F
GBA
IMPORTANT INFORMATION ABOUT THIS
GEOTECHNICAL ENGINEERING REPORT
Geotechnical-Engineering Report
Important Information about This
Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes.
While you cannot eliminate all such risks, you can manage them. The following information is provided to help.
The Geoprofessional Business Association (GBA)
has prepared this advisory to help you – assumedly
a client representative – interpret and apply this
geotechnical-engineering report as effectively as
possible. In that way, you can benefit from a lowered
exposure to problems associated with subsurface
conditions at project sites and development of
them that, for decades, have been a principal cause
of construction delays, cost overruns, claims,
and disputes. If you have questions or want more
information about any of the issues discussed herein,
contact your GBA-member geotechnical engineer.
Active engagement in GBA exposes geotechnical
engineers to a wide array of risk-confrontation
techniques that can be of genuine benefit for
everyone involved with a construction project.
Understand the Geotechnical-Engineering Services
Provided for this Report
Geotechnical-engineering services typically include the planning, collection, interpretation, and analysis of exploratory data from widely spaced borings and/or test pits. Field data are combined with results from laboratory tests of soil and rock samples obtained from field exploration (if applicable), observations made during site reconnaissance, and historical information to form one or more models of the expected subsurface conditions beneath the site. Local geology and alterations of the site surface and subsurface by previous and proposed construction are also important considerations. Geotechnical engineers apply their engineering training, experience, and judgment to adapt the requirements of the prospective project to the subsurface model(s). Estimates are made of the subsurface conditions that will likely be exposed during construction as well as the expected performance of foundations and other structures being planned and/or affected by construction activities.
The culmination of these geotechnical-engineering services is typically a geotechnical-engineering report providing the data obtained, a discussion of the subsurface model(s), the engineering and geologic engineering assessments and analyses made, and the recommendations developed to satisfy the given requirements of the project. These reports may be titled investigations, explorations, studies, assessments, or evaluations.
Regardless of the title used, the geotechnical-engineering report is an engineering interpretation of the subsurface conditions within the context of the project and does not represent a close examination, systematic inquiry, or thorough investigation of all site and subsurface conditions.
Geotechnical-Engineering Services are Performed
for Specific Purposes, Persons, and Projects,
and At Specific Times
Geotechnical engineers structure their services to meet the specific needs, goals, and risk management preferences of their clients. A geotechnical-engineering study conducted for a given civil engineer will not likely meet the needs of a civil-works constructor or even a different civil engineer. Because each geotechnical-engineering study is unique, each geotechnical-engineering report is unique, prepared solely for the client.
Likewise, geotechnical-engineering services are performed for a specific project and purpose. For example, it is unlikely that a geotechnical- engineering study for a refrigerated warehouse will be the same as one prepared for a parking garage; and a few borings drilled during a preliminary study to evaluate site feasibility will not be adequate to develop geotechnical design recommendations for the project.
Do not rely on this report if your geotechnical engineer prepared it:
• for a different client;
• for a different project or purpose;
• for a different site (that may or may not include all or a portion of the original site); or
• before important events occurred at the site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like floods, droughts, earthquakes, or groundwater fluctuations.
Note, too, the reliability of a geotechnical-engineering report can be affected by the passage of time, because of factors like changed subsurface conditions; new or modified codes, standards, or regulations; or new techniques or tools. If you are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying the recommendations in it. A minor amount of additional testing or analysis after the passage of time – if any is required at all – could prevent major problems.
Read this Report in Full
Costly problems have occurred because those relying on a geotechnical- engineering report did not read the report in its entirety. Do not rely on an executive summary. Do not read selective elements only. Read and refer to the report in full.
You Need to Inform Your Geotechnical Engineer
About Change
Y our geotechnical engineer considered unique, project-specific factors when developing the scope of study behind this report and developing the confirmation-dependent recommendations the report conveys.
Typical changes that could erode the reliability of this report include those that affect:
• the site’s size or shape;
• the elevation, configuration, location, orientation,
function or weight of the proposed structure and
the desired performance criteria;
• the composition of the design team; or
• project ownership.
As a general rule, always inform your geotechnical engineer of project or site changes – even minor ones – and request an assessment of their impact. The geotechnical engineer who prepared this report cannot accept responsibility or liability for problems that arise because the geotechnical engineer was not informed about developments the engineer otherwise would have considered.
Most of the “Findings” Related in This Report
Are Professional Opinions
Before construction begins, geotechnical engineers explore a site’s subsurface using various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions only at those specific locations where sampling and testing is performed. The data derived from that sampling and testing were reviewed by your geotechnical engineer, who then applied professional judgement to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may differ – maybe significantly – from those indicated in this report. Confront that risk by retaining your geotechnical engineer to serve on the design team through project completion to obtain informed guidance quickly, whenever needed.
This Report’s Recommendations Are
Confirmation-Dependent
The recommendations included in this report – including any options or alternatives – are confirmation-dependent. In other words, they are not final, because the geotechnical engineer who developed them relied heavily on judgement and opinion to do so. Y our geotechnical engineer can finalize the recommendations only after observing actual subsurface conditions exposed during construction. If through observation your geotechnical engineer confirms that the conditions assumed to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. The geotechnical engineer who prepared this report cannot assume responsibility or liability for confirmation-dependent recommendations if you fail to retain that engineer to perform construction observation.
This Report Could Be Misinterpreted
Other design professionals’ misinterpretation of geotechnical- engineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a continuing member of the design team, to:
• confer with other design-team members;
• help develop specifications;
• review pertinent elements of other design professionals’ plans and specifications; and
• be available whenever geotechnical-engineering guidance is needed.
Y ou should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction- phase observations.
Give Constructors a Complete Report and Guidance
Some owners and design professionals mistakenly believe they can shift unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical-engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuously that you’ve included the material for information purposes only. To avoid misunderstanding, you may also want to note that “informational purposes” means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report. Be certain that constructors know they may learn about specific project requirements, including options selected from the report, only from the design drawings and specifications. Remind constructors that they may perform their own studies if they want to, and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstruction conferences can also be valuable in this respect.
Read Responsibility Provisions Closely
Some client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines. This happens in part because soil and rock on project sites are typically heterogeneous and not manufactured materials with well-defined engineering properties like steel and concrete. That lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes.
To confront that risk, geotechnical engineers commonly include explanatory provisions in their reports. Sometimes labeled “limitations, ” many of these provisions indicate where geotechnical engineers’ responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions.
Y our geotechnical engineer should respond fully and frankly.
Geoenvironmental Concerns Are Not Covered
The personnel, equipment, and techniques used to perform an environmental study – e.g., a “phase-one” or “phase-two” environmental site assessment – differ significantly from those used to perform a geotechnical-engineering study. For that reason, a geotechnical-engineering report does not usually provide environmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures. If you have not obtained your own environmental information about the project site, ask your geotechnical consultant for a recommendation on how to find environmental risk-management guidance.
Obtain Professional Assistance to Deal with
Moisture Infiltration and Mold
While your geotechnical engineer may have addressed groundwater, water infiltration, or similar issues in this report, the engineer’s services were not designed, conducted, or intended to prevent migration of moisture – including water vapor – from the soil through building slabs and walls and into the building interior, where it can cause mold growth and material-performance deficiencies.
Accordingly, proper implementation of the geotechnical engineer’s recommendations will not of itself be sufficient to prevent moisture infiltration. Confront the risk of moisture infiltration by including building-envelope or mold specialists on the design team.
Geotechnical engineers are not building-envelope or mold specialists.
Copyright 2019 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with GBA ’s specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind.
Any other firm, individual, or other entity that so uses this document without being a GBA member could be committing negligent or intentional (fraudulent) misrepresentation.
Telephone: 301/565-2733
e-mail: [email protected] www.geoprofessional.org - 33 -
Appendix 4: Historical Site Conditions
Phase I Environmental Site Assessment or Other Information on Past Site Use - 34 -
Appendix 5: LID Infeasibility
LID Technical Infeasibility Analysis
- 35 -
Appendix 6: BMP Design Details
BMP Sizing, Design Details and other Supporting Documentation
DCV CALCULATIONS
Date
D85= 0.68 inches
DMA
Type/ID
DMA Area
(square feet)
Post-Project Surface
Type
Effective
Imperivous
Fraction, If
DMA
Runoff
Factor
DMA Areas x
Runoff Factor
Design
Storm
Depth (in)
Design Capture
Volume, VBMP
(cubic feet)
Proposed
Volume on
Plans (cubic
feet)
A-1 1,179,020 Mixed Surface Types 0.65 0.45 529590.1
A-2 131,002 Natural (B Soil) 0.15 0.14 18529.7
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1310022 548119.8 0.68 31060.1 34,422
Notes:
Total
85th Percentile, 24-hour Rainfall Depth,
from the Isohyetal Map in Handbook Appendix E
Insert additional rows if needed to accommodate all DMAs draining to the BMP Santa Ana Watershed
- BMP Design Volume, VBMP
(Rev. 10-2011)
Legend:
Required Entries
Calculated Cells
(Note this worksheet shall only be used in conjunction with BMP designs from the LID BMP Design Handbook ) Company Name PROACTIVE ENGINEERING CONSULTANTS 4/5/2022 Designed by SAM AGUILAR Case No
Company Project Number/Name 10.094
BMP Identification
Drainage Management Area Tabulation
Design Rainfall Depth
BMP NAME / ID DMA A - EXTENDED DETENTION BASIN NO. 1
Must match Name/ID used on BMP Design Calculation Sheet
Conservative assumption,
since project is single family
residential.
Developed Cover Types Effective Impervious Fraction
Roofs 1.00
Concrete or Asphalt 1.00
Grouted or Gapless Paving Blocks 1.00
Compacted Soil (e.g. unpaved parking) 0.40
Decomposed Granite 0.40
Permeable Paving Blocks w/ Sand Filled Gap 0.25
Class 2 Base 0.30
Gravel or Class 2 Permeable Base 0.10
Pervious Concrete / Porous Asphalt 0.10
Open and Porous Pavers 0.10
Turf block 0.10
Ornamental Landscaping 0.10
Natural (A Soil) 0.03
Natural (B Soil) 0.15
Natural (C Soil) 0.30
Natural (D Soil) 0.40
Mixed Surface Types
Effective Impervious Fraction
Use this table to determine the effective impervious fraction for the V BMP and QBMP calculation sheets
USED FOR LANDSCAPE/
BASIN AREAS
BMP SIZING CALCULATIONS
No.
Company Name: Date:
Designed by: County/City Case No.:
Tributary Area (BMP Subarea) AT = 30.1 acres
Enter VBMP, determined from Section 2.1 of this Handbook VBMP= 31,060 ft3 101 ft
47 ft
z = 4 :1
DB = 5.00 ft
DFB = 0.00 ft
DREQ = 7.7 ft
DO = 5.0 ft
BMP Subarea
Design Volume
Depth of freeboard (if used)
Minimum Required Allowance for Total Depth (including proposed basin depth, freeboard, minimum depth of bottom stage (DBS=0.33') Legend:
Basin Footprint
Width =
Length =
Overall Geometry
Length at Basin Bottom Surface
Width at Basin Bottom Surface
Side Slopes per "Basin Guidelines", Sect. 1.2
Proposed Basin Depth (with no freeboard)
and minimum filter depth (DFD=2.33'))
Depth from design water surface elevation to lowest orifice Required Entries
Calculated CellsExtended Detention Basin Design Procedure Meets 1.5 : 1 requirement?
DTOT = 5.00 ft
Slope = 1.00 %
Slope = 1 %
VBasin = 45166 ft3
VFB = 956 ft3
Forebay Depth (height of berm) DFBY = 0.67 ft
Minimum Forebay Surface Area AFB = 1427 ft2
W = 2.00 in
Basin Invert Transverse Slope (1% min)
Rectangular weir (notch)
Basin Design
Basin Design
Proposed Total Basin Depth (proposed depth plus freeboard) Basin Volume
Bottom Stage
Forebay Design
Basin Invert Longitudinal Slope
Forebay Volume (3 - 5% VBMP)
Depth = 24 inches
Width = 48 inches
Trench Invert Longitudinal Slope Slope = 1 %
Depth = 24 inches
Width = 18 inches
Slope = 1 %
S = 25 feet
DBS = 6 in
ABS = 531 ft2
266 ft3
Depth of ASTM-C33 sand (18 inch minimum)
Ds = 18 inches
Diameter of Subdrains
f = 6 in s = 10 ft. on center
Width (48 inches minimum)
Dry Weather and Low-Flow Management
Low-Flow Trench (see graphic below)
Is VBS no less than 0.5% VBMP? OK
Collector Trenches (see graphic below)
Width (18 inches minimum)
Trench Invert Longitudinal Slope
Surface Area of Bottom Stage
Spacing (25 feet on center maximum)
Dry Weather Ponded Volume (above sand layer) VBS =
Depth (24 inches minimum, gravel filled)
Depth (24 inches minimum)
Subdrain Spacing
Depth of the Bottom Stage (4" minimum ponding)
Bottom Stage (Sand Filter) Design
Transverse Slope
(1% min)
AASHTO No. 2
Coarse aggregate
24" (min)
48" (min)
18" (min)
24" (min)
Low-Flow Trench Collector Trench
DBS
Outlet Design
0.0000 0.0000
Discharge Coefficient, 0.0666 0.044 16.05
0.0943 0.091 7.02
Default, C = 0.66 0.1155 0.140 5.70
0.1333 0.193 5.08
Other, C = 0.66 0.1491 0.247 4.70
0.1633 0.305 4.47
0.1764 0.366 4.32
0.1886 0.429 4.20
0.2000 0.496 4.13
0.2108 0.565 4.09
0.2212 0.637 4.01
d = 2 inches 0.2310 0.711 4.00
0.2404 0.790 4.04
n = 1 per row 0.2495 0.872
0.2582 0.957
N = 1 rows 1.045
Aeff = 0.022 ft2 per row
or
Aeff = 3.140 in2 per row
25.15 hrs
71.83 hrs
∑ = 71.83
Notes:
Discharge
(cfs)
Volume
(acre-ft)
OK
number of orifice rows, N (from the bottom up).
OK
has drained from the basin(within 72 hours):
Orifice Diameter, d; number of orifices per row, n; and Time (100 %) =
From outflow hydrograph, the time where 100% VBMP
has drained from the basin (24 hour minimum):
Time (50%) =
From outflow hydrograph, the time where 50% of VBMP
9.67 7.67
10.00 5.67
9.33 3.67
8.67 8.33
Orifice Area (ft2)
6.67 9.00
8.00 7.33
7.00 6.33
6.00 2.00
1.67 2.33
4.33 4.00
3.00 2.67
3.33 4.67
5.33 5.00
Flow Rate, Q (cfs)
0 Assume an orifice area. Based on the
information provided above, the spreadsheet
provides discharge vs. stage data. Enter the
volume vs. stage data for each interval. This
information is used to route the volume through
the basin. The size of the orifice is acceptable
when the data shows that less than 50% of
VBMP has drained in 24 hours, and that 100%
drawdown occurs within 72 hours.
Q=CA[2g(H-Ho)]0.5
Basin Outlet Design
Dt (hrs.)Headwater Elev.
/ Stage (ft)
1.00 1.33
0.67 0.33
ISOHYETAL MAP
RIVERSIDE COUNTY FLOOD
CONTROL AND WATER
CONSERVATION DISTRICT
Isohyetal Map
for the 85th Percentile
24 hour Storm Event
July 2011
Rain Gage Locations
PROJECT LOCATION
0.68 - 36 -
Appendix 7: Hydromodification
Supporting Detail Relating to Hydrologic Conditions of Concern
PROJECT LOCATION
MITIGATION NOT
REQUIRED
- 37 -
Appendix 8: Source Control
Pollutant Sources/Source Control Checklist
- 38 -
Appendix 9: O&M
Operation and Maintenance Plan and Documentation of Finance, Maintenance and Recording Mechanisms
TO BE COMPLETED DURING FINAL
ENGINEERING
- 6 -
Appendix 10: Educational Materials
BMP Fact Sheets, Maintenance Guidelines and Other End-User BMP Information -39-
BMP FACT SHEETS
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
3.6 Extended Detention Basin
Type of BMP LID - Biotreatment
Treatment Mechanisms Sedimentation, Infiltration, Biofiltration, Evapotranspiration, and Evaporation
Minimum Tributary Drainage Area 5 acres
Other Names Enhanced Water Quality Basin
Overview
The Extended Detention Basin (EDB) is designed to detain the design volume of stormwater, V BMP, and maximize opportunities for volume losses through infiltration, evaporation, evapotranspiration and surface wetting . Additional pollutant removal is provided through sedimentation, in which pollutants can attach to sediment accumulated in the basin through the process of settling. Stormwater enters the EDB through a forebay where any trash, debris, and sediment accumulate for easy removal. Flows from the forebay enter the basin which is vegetated with native grasses that enhance infiltration and evapotranspiration, and which is interspersed with gravel- filled trenches that help further enhance infiltration. Water that does not get infiltrated or evapotranspired is conveyed to the bottom stage of the basin. At the bottom stage of the basin, low or incidental dry weather flows will be treated through a sand filter and collected in a subdrain structure. Any a dditional flows will be detained in the basin for an extended period by incorporating an outlet structure that is more restrictive than a traditional detention basin outlet. The restrictive outlet structure extends the drawdown time of the basin which further allows particles and associated pollutants to settle out before exiting the basin, while maximizing opportunities for additional incidental volume losses.
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
Figure 1 – Extended Detention Basin
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
Siting Considerations
Soils: EDBs can be used with almost all soils and geology. However, pollutant removal effectiveness is greatly improved when the underlying soil permits at least some infiltration.
Tributary Area: EDBs should only be used where the tributary drainage area is at leas t 5 acres, since meeting the draw -down requirements (discussed below) for smaller areas would result in very small outlet orifice diameters which would be prone to clogging.
Proximity to Receiving Waters: All site runoff must be treated to the MEP with appropriate BMPs before being discharged into Receiving Waters; as such the EDB cannot be constructed in-line within Receiving Waters.
Setbacks: Due to the infiltration characteristics incorporated into the EDB design, the lowest pervious point (beneath the filter drain) of the extended detention fac ility should be a minimum of 10' above the seasonal high groundwater table. All other setbacks shall be in accordance with applicable standards of the “Basin Guidelines” (Appendix C) or other guidelines issued by the Engineering Authority (EA).
Basin Guidelines: See Section 1 of the “Basin Guidelines” (Appendix C) for additional requirements (i.e., fencing, maintenance access, etc.) that may be required by the Engineering Authority (EA).
Landscaping Requirements
Basin vegetation provides erosion protection, enhances evapotranspiration and infiltration, and improves pollutant removal. The upper stage basin surface , berms and side slopes shall be planted with native grasses . Proper landscape management is also required to ensure that the vegetation does not contribute to water pollution through the use of pesticides, herbicides, or fertilizers. Landscaping shall be in accordance with applicable standards of the “ Basin Guidelines” (Appendix C) or other guidelines issued by the EA.
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
Maintenance Guidelines
Schedule Inspection and Maintenance Activity
During every scheduled
maintenance check (per below),
and as needed at other times
• Maintain vegetation as needed . Use of fertilizers, pesticides and herbicides should be strongly avoided to ensure they don’t contribute to water pollution. If appropriate native plant selections and other IPM methods are used, such products shouldn’t be needed. If such projects are used:
o Care should be taken to avoid contact with the low -
flow or other trenches, and the media filter in the
bottom stage.
o Products shall be applied in accordance with their
labeling, especially in relation to application to water, and in areas subjected to flooding.
o Fertilizers should not be applied within 15 days before, after, or during the rainy season.
• No ponded water should be present for more than 72 hours to avoid nuisance or vector problems. No algae formation should be visible.
Correct problems as needed.
Annually. If possible, schedule
these inspections before the
beginning of the rain season to
allow for any repairs to occur
before rains occur.
• Remove debris and litter from the entire basin
• Inspect hydraulic and structural facilities. Examine the outlet for clogging, the embankment and spillway integrity, as well as damage to any structural element.
• Check for erosion, slumping and overgrowth. Repair as needed. • Inspect sand media at the filter drain to verify it is allowing acceptable infiltration. Scarify top 3 inches by raking the filter drain’s sand surface annually.
• Check the media filter underdrains (via the cleanout) for damage or clogging. Repair as needed.
• Remove accumulated sediment and debris from the forebay , and ensure that the notch weir is clear and will allow proper drainage. • Check gravel filled low flow and collector trenches for sediment buildup and repair as needed.
Every 5 years or sooner
(depending on whether observed
drain times to empty the basin
are less than 72 hours).
• Remove the top 3 inches of sand from the filter drain and backfill with 3 inches of new sand to return the sand layer to its original depth .
When scarification or removal of the top 3 inches of sand is no longer effective, remove and replace sand filter layer.
Whenever substantial sediment
accumulation has occurred.
• Remove accumulated sediment from the bottom of the basin.
Removal should extend to original basin depth.
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
Design Summary
Note: The information contained in this BMP Factsheet is intended to be a summary of design considerations and requirements. Additional information which applies to all detention basins may be found in the “Basin Guidelines” (Appendix C). In addition, in formation herein may be superseded by other guidelines issued by the Engineering Authority.
Design Procedure
These steps correspond to and provide a description of the information required in the EDB Design Worksheet.
1. Find the Design Volume, VBMP.
a) Enter the tributary area, AT to the BMP. The minimum tributary area is 5 acres. b) Enter the Design Volume, VBMP, determined from Section 2.1 of this Handbook.
Design Parameter Extended Detention Basin
Drawdown time (total) 72 hours 2,3
Minimum drawdown time for 50% VBMP 24 hours 2
Minimum tributary area 5 acres 2
Outlet erosion control Energy dissipaters to reduce velocities1 Forebay volume 3 to 5 % of VBMP
3 Basin Invert Longitudinal Slope (min.) 1%
Basin Invert Transverse (cross) Slope (min) 1%
Low-flow trench width (min.) 48 inches
Low-flow trench depth (min.) 24 inches
Slope of low-flow trench along bottom
excavated Surface (max.) 1%
Slope of gravel collector trenches along
bottom excavated surface (max.) 1 %
Length to width ratio (min.) 1.5:1
Basin depth (min.) 1 foot 3
Bottom stage volume 0.5 % of VBMP 3
Bottom stage depth (min) 0.33 feet 3
Filter drain depth (min) 2.33 feet 3
1. Ventura County’s Technical Guidance Manual for Stormwater Quality Control Measures
2. CA Stormwater BMP Handbook for New Development and Significant Redevelopment
3. Denver, Colorado’s UDFCD Drainage Criteria Manual, Volume 3
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
2. Basin Footprint
a) Enter the length and width of the EDB. The length shall be measured between the inlet to the basin and the outlet structure; and the width shall be measured at the widest point of the basin invert . The length to width ratio should be 1.5:1 or longer to prevent short-circuiting and increase the overall effectiveness of the BMP.
b) Enter the internal basin side slopes. See the “Basin Guidelines” (Appendix C) for side slope requirements. If variable internal side -slopes are used, enter the steepest slope that will be used.
c) Using Figure 1 as a guide, e nter the proposed basin depth, D B, and the freeboard depth, D FB. B ased on the information provided, the spreadsheet will ca lculate the minimum total depth required, D REQ, for this BMP. D REQ is the depth from the bottom of the underdrain layer in the bottom stage (see step 5c) , to the top o f the freeboard. This calculated minimum required depth can be used to determine if enough elevation difference is available within the design topography to allow for use of this BMP.
d) Additionally, the basin depth D B is equal to D O, which is the depth from the design pond water surface elevation to the lowest orifice in the outlet structure. D O is confirmed by the spreadsheet and is used in the Basin Outlet Design described in step 6 below. It should be noted that this lowest orifice is a critical elevation in the design of this BMP. The Volume of the Basin V Basin described in step 3d) is the volume of water above this lowest orifice. This lowest-orifice also represents the dry weather ponded water surface discussed in step 5c below. Below this elevation there must be a minimum of a 4 -inch drop down to the surface of the Sand Filter in the bottom stage.
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
3. Basin Design
a) The Total Basin Depth , DTOT, is calculated automatically, and is the sum of the basin depth DB plus the freeboard depth DFB.
b) Enter the longitudinal slope of the basin invert. This slope must be at least 1% and is measured along the low flow trench between the forebay and the bottom s tage.
Note that the surface of the sand layer in the bottom stage must be level (see Figure 1).
c) Enter the transverse slope of the basin invert. This transverse (cross sectional) slope must be at least 1% sloped toward the low flow trench.
d) Enter the Volume of the Basin, V Basin. This volume must be the actual volume of water held within the basin as substantiated by modeling or appropriate volumetric calculations, and must be equal to or greater than V
BMP. This volume must be held
above the lowest orifice in the Basin Outlet Design described in step 6 below.
4. Forebay Design
All flows must enter the basin through the
forebay. The forebay provides a location for th e
settlement and collection of larger particles, and
any other trash or debris. A relatively smooth and
level concrete bottom surface should be provided
to facilitate mechanical removal of any
accumulated sediment, trash and debris.
a) Enter the Forebay Volu me VFB. This
volume must be from 3 to 5 percent of
V
BMP.
b) A rock or concrete berm must be constructed to d etain water before it drains into the basin. The top of the berm shall be set no higher than the invert of the inlet conveyance. Enter the Forebay Depth, D
FBY.
c) The spreadsheet will calculate the minimum surface area of the forebay, A FB, based on the pro vided Forebay Volume and Depth. Ensure that the plans provide for a forbay area at least this large.
d) Although the forebay will be well submerged in the design event, a full height rectangular notch-type weir shall be constructed through the berm to prevent permanent ponding in the forebay, and allow water to slowly and fully drain to the main body of the basin. This notch should be offset from the inf low streamline to prevent low-flows from short circuiting. Enter the width, W, of this rectangular notch weir. The width shall not be less than 1.5 inches to prevent clogging . Additionally, Figure 2: Forebay filled with storm water
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
immediately outside the notch construct a minimum 1 -foot by 1 -foot gravel pad to prevent vegetative growth within the basin invert from blocking the notch.
5. Dry Weather and Low-Flow Management
The basin shall have both a low-flow gravel trench and a network of gravel collector trenches across the invert of the basin, as well as a bottom stage sand filter to treat low flows and dry weather flows (see Figure 1).
a) Low Flow Trench: The low-flow gravel trench conveys flow from the forebay to the bottom stage, while allowing fo r maximum
incidental infiltration and volume loss. The
trench shall be a minimum of 48 inches wide
by 24 inches deep. This trench shall be
unlined and backfilled with AASHTO No. 2
gravel (or similar) to the finished surface of
the basin invert, and shall n ot use
underdrains. The bottom excavated surface
of the low- flow trench shall be 1 percent or
flatter to promote infiltration.
b) Collector Trenches:
Gravel collector trenches beneath the top stage shall be arranged as illustrated in Figure 1 of Appendix C with minimal slope (1% maximum) along their bottom excavated surface to promote infiltration, and must extend from the low-flow trench to the toe of the basin side slopes. They shall be a minimum of 18-inches wide by 24 -inches deep, unlined and back filled with AASHTO No. 2 gravel (or similar) to the finished basin invert surface. The gravel collector trenches shall not use underdrains and shall be constructed with a maximum spacing of 25 feet, center to center. See Figure 1 of Appendix C.
c) Bottom Stage: A depressed sand filter drain area, referred to as the b ottom stage, must be constructed adjacent to the outlet structure to treat any dry weather flows.
To ensure that dry weather flows are treated through the sand filter and not discharged through the ori fice plate, the top surface of the sand filter must be depressed at least 4 inches below the lowest orifice in the outlet structure. This depressed area will create a micro pool of water that is then filtered down through the san d filter and out through under drains. Based on the minimum dimensions described below, the minimum depth of excavation below the lowest orifice in the outlet structure is 2.33 feet.
i. Enter the Depth of the b ottom stage, D BS. As mentioned above, this depth must be at least 4 inches, and extend down below the lowest orifice in the outlet structure.
ii. Enter the area of the bottom stage, A
BS.
Figure 3: Gravel filled low-flow trench
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Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
iii. Based on the D BS and A BS entered, the spreadsheet will calculate V BS. This volume is the volume of ponded water that will be held below the lowest orifice in the outlet structure, and above the surface of the sand filter. This volume must be at least 0.5% of VBMP.
iv. Enter the thickness of the ASTM C-33 sand layer that will b e provided, D S. A minimum thickness of 18 inches is required.
v. Below the sand layer, a minimum 10 -inch thick layer of gravel shall be installed with underdrains to drain the water that has been treated through the sand filter. The underdrains shall connect into the outlet structure. See Appendix B for standard underdrain construction. E nter the diameter of the underdrain pipe (minimum 6” dia.), and the spacing of the underdrains . The maximum spacing of the underdrains is 20 feet on center , however where the area of the bottom stage is particularly small (less than 500 square feet), the underdrain pipes shall be placed at no more than a 10-foot separation on center.
6. Basin Outlet Design
Figure 4: Basin Outlet Structure with Bottom Stage Shown Outlet structures for publicly maintained basins shall conform to District Standard Drawings WQ501 unless approved in advance by the local Engineering Authority (EA). This standardization is to provide for efficient maintenance. The basin outlet should be size d to release the design volume, VBMP, within a 72-hour period but 50 percent of VBMP within 24 hours. This is an iterative design process where an appropriate control orifice can be selected using the following steps:
a. Develop a Stage vs. Discharge Curve for the Outlet Structure
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Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
Estimate the orifice size and outlet plate configuration (number per row, etc.). Based on DO provided in the Basin Footprint section, the spreadsheet will automatically generate the stage vs. discharge relationship for this outlet:
Q = C*A*[2*g*(H-Ho)]0.5
Where:
Q = discharge (ft3/s)
C = orifice coefficient
A = area of the orifice (ft)
g = gravitational constant (32.2 ft2/s)
H = water surface elevation (ft)
Ho = orifice elevation (ft)
The lowest orifice shall be located with its centerline at the top of the bottom stage; at least 4 inches above the surface of the sand filter drain. To help avoid clogging, the minimum orifice diameter is limited to 3/8 inch. Since the 1/4 inch thickness of the orifice plate will be less than the orifice diameter, a value for C of 0.66 may be used. If another value for C is used, justification may be required.
b. Develop a Discharge/Volume vs. Stage Table for the Basin Based on the shape and size of the basin, develop a relationship between the stage and the volume of water in the basin. Since the orifice spacing is 4 inches on center for the standard orifice plate, the stage intervals must also be 4 inches. Enter the basin volume at each interval starting at the centerline of the lowest orifice. c. Route the Design Volume through the Basin
The spreadsheet assumes that the Design Volume , V
BMP, enters the basin
instantaneously and as such, no inflow/outflow hydrograph is necessary. The drawdown time for each stage becomes:
∆t = Vi/Q
Where:
∆ t = drawdown time for each stage
V i = the volume at each stage
Q = the flow rate corresponding to the headwater elevation at each stage.
The spreadsheet automatically determines the drawdown time from the sum of the ∆ t values for each stage. If the orifice size and plate configuration estimate meets th e
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Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
hydraulic retention time requirements (50% of the volume empties in not less than 24 hours, 100% of the volume empties in no more than 72 hours), the outlet is correctly sized. If these requirements are not met, select a new orifice size or configuration and repeat the process starting at Step 6a.
7. Outlet Protection
To prevent the orifices from clogging , t rash racks are re quired where perforated vertical outlet control plates are used . This allows for easier access to outlet orifices for inspection and cleaning. Trash racks shall be sized to prevent clogging of the primary water quality outlet without restricting the hydraulic capacity of the outlet control orifices. The orifice plate shall be protected with a trash rack conforming to Standard Drawing WQ501 (at end of this section) with at least six square feet
of open surface area or 25 times the
total orifice area, whichever is greater.
The rack shall be adequately secured to
prevent it from being removed or
opened when maintenance is not
occurring.
Overflow Structure Similar to Standard Drawing
Number WQ 501
(Photo courtesy of Colorado Association of
Stormwater Floodplain Managers)
Trash rack with screen
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Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
8. Overflow Outlet
Overflow outlets for publicly maintained basins shall conform to Standard Drawing WQ501 (at end of this section) unless approved in advance by the Engineering Authority (EA).
9. Embankment
Embankments sh all be designed in accordance with applicable standards of Riversid e County Flood Control District’s “Basin Guidelines” (Appendix C) or other guidelines issued by the Engineering Authority (EA) . Where applicable, embankment designs must additionally conform to the requirements of the State of California Division of Safety of Dams.
10. Spillway and Overflow Structures
Spillway and o verflow struct ures should be designed in accordance with applicable standards of the “Basin Guidelines” (Appendix C) or other guidelines issued by the Engineering Authority (EA).
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011
EXTENDED DETENTION BASIN BMP FACT SHEET
Riverside County - Low Impact Development BMP Design Handbook rev. 9/2011