HomeMy WebLinkAboutLD21-2039Permit Number: LD21-2039
LD - Onsite Improvements/ Mass & Rough Grading
Issued: 02/06/2025
Expired: 10/01/2025
Job Address: Tract Map 37925
Legal Description:
City of Temecula - Land Development Division
41000 Main Street - Temecula, CA 92590
Mailing Address: P.O. Box 9033 Temecula, CA 92589-9033
Phone: (951) 308-6395 Fax: (951) 694-6475
ANY NOTICE OR NOTICES REQUIRED TO BE GIVEN PURSUANT TO THIS PERMIT SHALL BE SERVED
ON THE OTHER PARTY BY FIRST CLASS MAIL, POSTAGE PREPAID, AT THE FOLLOWING ADDRESS:
Decatur Advisors Llc
Po Box 2016
Carlsbad, CA 92018
(619) 851-5121
Applicant:
Contractor:
Description of Work: The City Engineer hereby authorizes the Property Owner and Applicant (if different from
Property Owner) (hereinafter collectively referred to a "Permittee") to do the following work including backfilling,
compaction, surfacing and/or as outlined in the description of work below:
Description:
Tract Map 37925 Rough Grade for Planning Area 10 (PA10)
Separate permits required:
1. Haul route permit for the export of material
2. Encroachment permit for ALL work within the City right-of-way
3. Retaining wall permit
Earthwork includes 16,300 CY excavation/16,300 CY embankment/0 CY export. Maximum 2:1 slopes. All
grading and improvements shall be as specified on the approved plans and per the preliminary soils report.
Perform grading in accordance with approved Grading Plans dated . A pre-grading conference is required
48 hours (minimum) in advance of any work done under this permit with the grading contractor and
City Inspector. A pre-grade meeting is required 48 hours prior to any work. Permittee shall contact e-mail
LDinspections@TemeculaCA.gov to schedule a meeting. Any field changes to the plan shall be approved by
the City Engineer. All required permits and inspections by Building and Safety for walls, etc. shall be completed
prior to any releases and/or other permits issued or released. Traffic and dust control shall be reviewed and
approved by the inspector.
Permitee Date
City Engineer or Authorized Representative Date
02/06/2025
Page 1 of 1
P U B L I C W O R K S D E P A R T M E N T
ON-SITE CONSTRUCTION SECURITY WORKSHEET
(Updated As Of July 1, 2021)
Page 1 of 5
P R O J E C T :D A T E :
L D NUMBER:P A NO.:
63285
RCE #
On-Site Improvements
On-Site Drainage Improvements
WQMP Improvements
Total
Erosion & Sediment Control Improvements 112,000.00$
Date
Expiration Date
Civil Engineer's Stamp
137,000.00$
TM 37925
Engineer's Name (Typed or printed)
P A R C E L / T R A C T M A P : P A R C E L / L O T N O . :
4/4/2022TM 37925 ROUGH GRADING PA 10
LD-21-2039 PA 10
6/30/2022
The construction items and their quantities as shown on the attached worksheet are accurate for the construction of
the improvements required or implied to fulfill the Conditions of Approval for this project. The mathematical
extensions, using the City of Temecula's Unit Costs, are accurate for determining Fees.
D E S I G N E N G I N E E R S O P I N I O N O F C O N S T R U C T I O N S E C U R I T Y
RICHARD C. O'NEILL
P L E A S E R E A D I N S T R U C T I O N S B E L O W
3. For construction items not covered by "City of Temecula Construction Security Worksheet," Design Engineer is to
provide his opinion of construction cost and use that cost. If City of Temecula Unit Costs are determined to be too low, in
the opinion of the Design Engineer, the higher cost as provided by the Design Engineer should be used.
1. Quantities to be taken from improvement plans. Unit costs to be as provided on the "City of Temecula Construction
Security Worksheet."
2. Show Amounts to the nearest $500.00 (Rounded Up)
23,000.00$
2,000.00$
-$
May 4, 2022
Engineer's Signature
\\cp.rickeng.com\projects\C_RIV_G\17883\17883-H_PA10\Admin\Estimates\CSW On-Site FY 21-22_TM 37925.xls
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APPROVED BY
CITY OF TEMECULA
PUBLIC WORKS
valerie.ycong 05/09/2022
05/09/2022 05/09/2022
05/09/20
P U B L I C W O R K S D E P A R T M E N T
ON-SITE CONSTRUCTION SECURITY WORKSHEET
(Updated As Of July 1, 2021)
Page 2 of 5
PROJECT DATE 4/4/2022
QUANTITY UNIT ITEM
UNIT
COST AMOUNT
C.Y. Crushed Aggregate Base Material ( ") $ 71.00 $ -
TON A.C. Pavement ( " Thickness [4" Minimum]) $ 95.00 $ -
S.F. Remove A.C. Pavement $ 1.00 $ -
L.F. A.C. Berm (8") $ 10.50 $ -
L.F. Remove A.C. Berm $ 3.50 $ -
S.F. P.C.C. Cross Gutter and Aprons (Spandrels) $ 10.50 $ -
L.F. P.C.C. Curb & Gutter (Type A-6) $ 10.50 $ -
L.F. Remove Curb & Gutter $ 18.00 $ -
S.F. P.C.C. Sidewalk $ 6.25 $ -
S.F. Remove Sidewalk $ 10.00 $ -
S.F. P.C.C. Driveway Approach $ 8.25 $ -
S.F. 1' Step @ Curb / Maintenance Walk (Median) $ 4.25 $ -
920 L.F. Concrete V-Ditch $ 20.00 $ 18,400.00
EA ADA Access Ramps $ 1,545.00 $ -
L.F. Install Barricades $ 103.00 $ -
L.F. Remove Barricades $ 10.50 $ -
L.F. Utility Trench $ 10.50 $ -
EA Under Sidewalk Drain $ 2,000.00 $ -
EA Street Lights (including conduit) $ 5,150.00 $ -
EA Relocate Power Pole $ 10,000.00 $ -
L.F. Relocate Chain Link Fence $ 12.00 $ -
L.F. Remove Chain Link Fence $ 8.00 $ -
L.F. Retaining Wall $ 212.00 $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
Subtotal:
20% Contingency:
TOTAL:
$3,812.48
$22,874.88
TM 37925 ROUGH GRADING PA 10
O N - S I T E I M P R O V E M E N T S
$18,400.00
3.6% CPI Increase per City Resolution 05-101: $662.40
Unit Costs Updated On 7/1/2012 \\cp.rickeng.com\projects\C_RIV_G\17883\17883-H_PA10\Admin\Estimates\CSW On-Site FY 21-22_TM 37925.xls
P U B L I C W O R K S D E P A R T M E N T
ON-SITE CONSTRUCTION SECURITY WORKSHEET
(Updated As Of July 1, 2021)
Page 3 of 5
PROJECT DATE 3/8/2022
QUANTITY UNIT ITEM
UNIT
COST AMOUNT
L.F. 18" R.C.P. $ 116.00 $ -
L.F. 24" R.C.P. $ 136.00 $ -
L.F. 30" R.C.P. $ 158.00 $ -
L.F. 36" R.C.P. $ 183.00 $ -
L.F. 42" R.C.P. $ 210.00 $ -
L.F. 48" R.C.P. $ 242.00 $ -
L.F. Catch Basins $ 510.00 $ -
EA Inlet Type IX & X $ 1,854.00 $ -
EA Manhole at Junction $ 4,635.00 $ -
EA Manhole No. 1 $ 5,768.00 $ -
EA Manhole No. 2 $ 6,695.00 $ -
EA Manhole No. 3 $ 5,768.00 $ -
EA Manhole No. 4 $ 6,695.00 $ -
EA Transition Structure No. 1 $ 15,213.00 $ -
EA Transition Structure No. 3 $ 4,867.00 $ -
EA Junction Structure No. 1 $ 3,657.00 $ -
EA Junction Structure No. 2 $ 4,872.00 $ -
EA Junction Structure No. 6 $ 6,087.00 $ -
30 C.Y. Rip Rap $ 52.00 $ 1,560.00
C.Y. Rip Rap (Grouted) $ 86.00 $ -
EA CMP Riser $ 1,500.00 $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
Subtotal:
20% Contingency:
TOTAL:
$323.23
$1,939.39
TM 37925 ROUGH GRADING PA 10
O N - S I T E D R A I N A G E I M P R O V E M E N T S
$1,560.00
$56.16 3.6% CPI Increase per City Resolution 05-101:
Unit Costs Updated On 7/1/2012 \\cp.rickeng.com\projects\C_RIV_G\17883\17883-H_PA10\Admin\Estimates\CSW On-Site FY 21-22_TM 37925.xls
P U B L I C W O R K S D E P A R T M E N T
ON-SITE CONSTRUCTION SECURITY WORKSHEET
(Updated As Of July 1, 2021)
Page 4 of 5
PROJECT DATE 3/8/2022
QUANTITY UNIT ITEM
UNIT
COST AMOUNT
CF Bio-Retention (cell or basin) $ 5.00 $ -
Cartridges Cartridge Filtration Boxes (per cartridge) $ 3,000.00 $ -
EA Catch Basin Baffle Filters $ 3,500.00 $ -
EA Catch Basin Debris Baskets $ 1,500.00 $ -
SF Conventional Grass-lined swale $ 5.00 $ -
CF Gravel Infiltration (trench or basin) $ 6.00 $ -
LF Infiltration Chambers/Galleries/Wells $ 175.00 $ -
SF Porous Concrete and Asphalt $ 12.00 $ -
SF Porous Pavers $ 14.00 $ -
EA Proprietary Filtration Planters $ 35,000.00 $ -
EA Proprietary Hydrodynamic Separators $ 10,000.00 $ -
CF Proprietary Detention/Retention Modular Boxes $ 10.00 $ -
EA Proprietary Tree Boxes $ 12,000.00 $ -
CF Raised Planter Boxes $ 6.00 $ -
CF Sand Filter (trench or basin) $ 4.00 $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
Subtotal:
20% Contingency:
TOTAL:
3.6% CPI Increase per City Resolution 05-101: $0.00
$0.00
$0.00
TM 37925 ROUGH GRADING PA 10
W A T E R Q U A L I T Y M A N A G E M E N T P L A N I M P R O V E M E N T S
$0.00
Unit Costs Updated On 7/1/2012 \\cp.rickeng.com\projects\C_RIV_G\17883\17883-H_PA10\Admin\Estimates\CSW On-Site FY 21-22_TM 37925.xls
P U B L I C W O R K S D E P A R T M E N T
ON-SITE CONSTRUCTION SECURITY WORKSHEET
(Updated As Of July 1, 2021)
Page 5 of 5
PROJECT DATE 3/8/2022
QUANTITY UNIT ITEM
UNIT
COST AMOUNT
EA Concrete Washout (with disposal) $ 3,000.00 $ -
CF Desilting Basin $ 1.30 $ -
5,050 LF Fiber Roll $ 6.50 $ 32,825.00
1,600 EA Gravel Bags $ 4.00 $ 6,400.00
LF Hay Bale $ 7.60 $ -
44,000 SF Hydroseeding / Hydro Mulch (with Bonded Fiber matrix) $ 0.15 $ 6,600.00
SF Hydroseeding / Hydro Mulch (without Bonded Fiber matrix) $ 0.10 $ -
SF Plastic Liner (visqueen) $ 0.30 $ -
3,700 LF Silt Fence (non-reinforced) $ 7.50 $ 27,750.00
LF Silt Fence (reinforced) $ 10.00 $ -
EA Stabilized Construction Entrance (with plates) $ 3,390.00 $ -
1 EA Stabilized Construction Entrance (without plates) $ 2,400.00 $ 2,400.00
SF Straw / Coconut Fiber Mat $ 0.28 $ -
SF Pyromat $ 1.00 $ -
175,800 SF Pad Stabalization Soil Binder (per CASQA EC-3) $ 0.08 $ 14,064.00
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
$ - $ -
Subtotal:
20% Contingency:
TOTAL:
3.6% CPI Increase per City Resolution 05-101: $3,241.40
$18,656.08
$111,936.48
TM 37925 ROUGH GRADING PA 10
E R O S I O N & S E D I M E N T C O N T R O L I M P R O V E M E N T S
$90,039.00
Unit Costs Updated On 7/1/2012 \\cp.rickeng.com\projects\C_RIV_G\17883\17883-H_PA10\Admin\Estimates\CSW On-Site FY 21-22_TM 37925.xls
FINAL DRAINAGE STUDY
FOR
WINGSWEEP PROPERTY
PLANNING AREA 10
Tract #37925
Job Number 17883-H
April 16, 2021
Revised: August 30, 2021
APPROVED BY
CITY OF TEMECULA
PUBLIC WORKS
valerie.caragan 01/22/2025
01/22/2025 01/22/2025
01/22/20
FINAL DRAINAGE STUDY
FOR
WINGSWEEP PROPERTY PLANNING AREA 10
Tract #37925
Job Number 17883-H
___________________________________
Brendan Hastie, P.E.
R.C.E. #65809, Exp. 9/23
Prepared for:
Wingsweep Corporation
15535 San Fernando Mission Boulevard, Suite 310
Mission Hills, California 91345
(619) 818-3596
Prepared by:
Rick Engineering Company
Water Resources Division
5620 Friars Road
San Diego, California 92110-2596
(619) 291-0707
April 16, 2021
Revised: August 30, 2021
Prepared by: BH:JR:vs/C_RIV_G//Report/17883-H.004
Rick Engineering Company – Water Resources Division 4-16-21
Revised: 8-30-21
i
FINAL DRAINAGE STUDY
FOR
WINGSWEEP PLANNING AREA 10
TRACT #37925
REVISION PAGE
August 30, 2021
This final engineering Drainage Study presents a revision to the April 16, 2021 report pursuant to the 1st
plan check redline comments by the City of Temecula. Responses to redline comments by Rick
Engineering have been included on the redline comments and have been presented separately with this
submittal.
Prepared by: BH:JR:vs/C_RIV_G//Report/17883-H.004
Rick Engineering Company – Water Resources Division 4-16-21
Revised: 8-30-21
TABLE OF CONTENTS
Revision Page Dated August 30, 2021 ............................................................................................... i
1.0 INTRODUCTION ...................................................................................................................1
2.0 HYDROLOGY ........................................................................................................................4
3.0 HYDRAULICS ........................................................................................................................7
4.0 FLOOD CONTROL DETENTION ANALYSIS ....................................................................9
5.0 ROUGH GRADING BASIN .................................................................................................10
6.0 CONCLUSION ......................................................................................................................11
Appendices:
Appendix 1: FEMA FIRMette
Appendix 2: Hydrologic Backup Information
Appendix 3: Drainage Study Map for Wingsweep PA10 (Pre-Project)
Appendix 4: Drainage Study Map for Wingsweep PA10 (Post-Project)
Appendix 5: Hydrology AES Output (Pre-project & Post-project)
Appendix 6: Inlet Sizing
Appendix 7: Storm Drain Sizing
Appendix 8: Rough Grade Condition CMP Overflow Sizing
Appendix 9: Detention Analysis Results
Prepared by: BH:JR:vs/C_RIV_G/Report/17883-H.004
Rick Engineering Company – Water Resources Division 4-16-21
Revised: 8-30-21
1
1.0 INTRODUCTION
1.1 Project Description
This drainage study presents hydrologic and hydraulic analyses for the proposed Wingsweep
Property Planning Area 10 project (herein referred to as the “project”). The project proposes the
development of approximately 8.1 acres northwest of Butterfield Sage Road Murrieta Hot Springs
Road. The project consists of 13 residential single-family lots and an associated street. The project
is located in the City of Temecula, California. Please refer to Figure 1: Vicinity Map located at the
end of this section for the project location.
1.1 Drainage Characteristics
The pre-project condition of the site consists of undeveloped area which has been previously mass
graded (and compacted) by others per Mass Grading Plan number LD04-004GR. Most of the
runoff from the site flows southwest towards an existing temporary sedimentation trap/basin
located in the southwest corner prior to discharging to Murrieta Hot Springs Road, Butterfield
Stage Road and then to Santa Gertrudis Creek.
In the post-project condition, the drainage characteristics from the site (Drainage Basin 1000) will
be very similar as compared to the pre-project conditions. Onsite runoff will be collected in a
proposed biofiltration basin BMP (replacing the existing sedimentation basin in the southwest
corner) prior to discharging to the Santa Gertrudis Creek. The biofiltration BMP will provide
pollutant control, hydromodification management, and flood control benefits. Runoff is conveyed
offsite to an existing stub out to a storm drain system in Murrieta Hot Springs Road that conveys
runoff to Santa Gertrudis Creek.
Prepared by: BH:JR:vs/C_RIV_G/Report/17883-H.004
Rick Engineering Company – Water Resources Division 4-16-21
Revised: 8-30-21
2
1.3 FEMA Flood Hazard Zone Information
The water courses around the project have been identified by the Federal Emergency Management
Agency (FEMA) as Zone X. This is an area of ‘Undetermined Flood Hazard’. The project is
shown on the FEMA Flood Insurance Rate Map (FIRM) number 06065C2740G, effective August
28, 2008 and labeled as Zone X. No FEMA submittals are anticipated to be required for this
project. As a reference, a copy of the FEMA FIRMette is provided in Appendix 1 of this report.
The proposed development is anticipated to be outside of the FEMA 100-year floodplain and
floodway hazard area (i.e. – Zone A and Zone AE); therefore, the potential risk associated with
flooding hazard is anticipated to be very minimal.
1.4 Water Quality and Hydromodification Management
A Water Quality Management Plan (WQMP) has been prepared for the project as well. The report
is titled, “Water Quality Management Plan (WQMP) for Wingsweep PA10A – Tract # 37925,”
dated August 30, 2021, prepared by Rick Engineering Company (Job Number 17883-H). The
WQMP documents how the project addresses the requirements regarding permanent stormwater
quality and hydromodification management, in accordance with the stormwater guidance
document titled, “City of Temecula Best Management Practice (BMP) Design Manual,” dated July
2018.
Prepared by: BH:JR:vs/C_RIV_G/Report/17883-H.004
Rick Engineering Company – Water Resources Division 4-16-21
Revised: 8-30-21
3
Figure 1: Vicinity Map
Prepared by: BH:JR:vs/C_RIV_G/Report/17883-H.004
Rick Engineering Company – Water Resources Division 4-16-21
Revised: 8-30-21
4
2.0 HYDROLOGY
Hydrologic calculations were computed in accordance with the Riverside County Flood Control
and Water Conservation District - Hydrology Manual, dated April 1978 (manual). The Advanced
Engineering Software (AES) 2014 Rational Method Analysis (Version 21.0) program was used to
perform the hydrologic analysis in this study.
The AES hydrologic model is developed by creating independent node-link models of each interior
drainage basin and linking these sub-models together at confluence points. The program has the
capability to perform calculations for 15 hydrologic processes. These processes are assigned code
numbers that appear in the results. The code numbers and their significances are as follows:
Subarea Hydrologic Processes (Codes)
Code 0: Enter comment
Code 1: Confluence analysis at a node
Code 2: Initial subarea analysis
Code 3: Pipe/Box/Culvert travel time (computer-estimated size)
Code 4: Pipe/Box/Culvert travel time (user-specified size)
Code 5: Open channel travel time
Code 6: Street flow analysis through a subarea
Code 7: User-specified hydrology data at a node
Code 8: Addition of the subarea runoff to main-stream
Code 9: V-Gutter flow through thru subarea
Code 10: Copy main-stream data onto a memory bank
Code 11: Confluence a memory bank with the main-stream memory
Code 12: Clear a memory bank
Code 13: Clear the main-stream
Code 14: Copy a memory bank onto the main-stream memory
Code 15: Hydrologic data bank storage functions
Code 16: User-specified source flow at a node
Prepared by: BH:JR:vs/C_RIV_G/Report/17883-H.004
Rick Engineering Company – Water Resources Division 4-16-21
Revised: 8-30-21
5
In order to perform the hydrologic analysis; base information for the study area is required. This
information includes the drainage facility locations and sizes, land uses, flow patterns, drainage
basin boundaries, and topographic elevations. Compiled Hydrologic backup is included as
Appendix 2 to this report. The hydrologic workmaps for this project are included in Appendices 3
and 4 to this report.
Area
Watersheds were delineated to distinguish areas with similar flow characteristics and hydrologic
properties as well as to determine peak flows at confluence points, existing and proposed storm
drain facilities, and to facilitate hydraulic analyses. Drainage basin boundaries, flow patterns, and
topographic elevations are shown on the hydrologic workmap for the proposed condition, included
in Appendix 3 and 4.
Time of Concentration/Intensity
The time of concentration was calculated using AES to determine the intensity for the 100-year
storm events. The rainfall intensity was calculated in AES using the 10 and 60-minute intensity
values for the “Murrieta – Temecula & Rancho California” values from Plate D-4.1 (4 of 6). An
annotated chart has been included in Appendix 2.
Runoff Coefficient
The runoff coefficients used for each minor basin were calculated by the AES software based on
the user-entered information of the hydrologic soil group and land use for each basin. The land use
across the project varies from impervious parking lot and walkways to amended landscape. The
percentage of impervious area in each subdrainage area was used to determine the land use entered
within AES.
Hydrologic soil group data is available for the site through the Natural Resource Conservation
Service (NRCS) Web Soil Survey, showing most of the site as Type ‘C’ soil. However, due to the
compaction condition resulting from the majority of the site being previously mass graded over a
decade ago, the site infiltration capacity was understood to be reduced. Therefore, for the purpose
of hydrologic modeling, Type ‘D’ soils were used to calculate runoff coefficients. In a similar
fashion, where improvements are proposed, the underlying soils are assumed to be Type ‘D’ where
Prepared by: BH:JR:vs/C_RIV_G/Report/17883-H.004
Rick Engineering Company – Water Resources Division 4-16-21
Revised: 8-30-21
6
improvements are proposed due to the compaction condition and to also provide a more
conservative peak flow rate for the purpose of sizing proposed storm drain pipes and structures.
2.1 Hydrologic Results
The discharges resulting from the 100-year storm event have been calculated for the proposed
condition of the project site. Hydrologic workmaps for the pre-project and post-project conditions
have been prepared and can be found in Appendices 3 and 4. Also, hydrologic calculation backup
information has been included in Appendix 2. The AES Rational Method results are provided in
Appendix 5 for the pre-project and post-project condition.
The hydrologic results for the pre- and post-project conditions can be found in Table 2.1. These
results show the project peak flow rates for the storm event before they are detained.
Table 2.1 – Hydrologic Summary for PA 10 (100-year Peak Flow Rate)
Drainage
Basin3
Pre-project1 Post-project1
Tc
(minutes)
Total Area
(Acres)
Peak Flow
Rate, Q100
(cfs)2
Tc
(minutes)
Total Area
(Acres)
Peak Flow
Rate, Q100
(cfs)2
1000 15.7 5.9 12.5 10.4 5.9 17.4
Note:
1: Refer to Appendix 2 for supporting information. Runoff coefficient is based on the undeveloped cover and single family
residential (1/4-acre), per the 1978 RCFC Hydrology Manual. For intensity, velocity, and more details, please refer to the
hydrologic analysis results in Appendix 5.
2: cfs= cubic feet per second.
3: Refer to Appendix 3 and 4 for Drainage Study Maps
Prepared by: BH:JR:vs/C_RIV_G/Report/17883-H.004
Rick Engineering Company – Water Resources Division 4-16-21
Revised: 8-30-21
7
3.0 HYDRAULICS
3.1 Hydraulic Methodology and Criteria
The 100-year proposed peak flow rates determined using the Modified Rational Method were used
to determine sizes for the on-site storm drain system and open channels/swales (where applicable).
Additional hydraulic analyses such as proposed inlet sizing were also prepared as part of final
engineering for this project.
3.1.1 Inlet Sizing
Inlets were sized based on RCFC&WCD design standards and have been sized for the 100-year
storm event. Each inlet was sized to provide 100% capture of the flow draining to the inlet. Inlets
were located such that the flow in the street is contained within the right-of-way for the 100-year
storm event. Inlet lengths were verified using the Bentley FlowMaster V8i computer program.
Calculations of minimum inlet lengths are included as Appendix 6 to this drainage study. The
proposed inlet lengths and locations are shown by the development plans for the project.
3.1.2 Storm Drain Pipe Flow Analysis
In association with the final engineering analysis conducted for the project, the Water Surface
Profile Gradient Program (WSPGW) version 14.05 from the CivilDesign Corporation was used to
model each public storm drain system. WSPGW Pipe Flow computer analyses correspond to the
pipe stationing shown by the development plans accompanying this submittal, and calculated flow
rates are obtained from the findings of the hydrologic analysis presented by this drainage study.
Results of the pipe flow analyses for the velocity and capacity models are included with Appendix
7.
The Manning’s roughness coefficient “n” of 0.013 was used for the hydraulic calculations and is
typically used for reinforced concrete pipe (RCP). For street gutter flows, and V-Ditch flows, a
Manning’s roughness coefficient “n” of 0.015 was used.
Prepared by: BH:JR:vs/C_RIV_G/Report/17883-H.004
Rick Engineering Company – Water Resources Division 4-16-21
Revised: 8-30-21
8
The AES rational method results located in the Appendix 5 of this report may be referenced for
further information concerning pipe flow rates.
3.1.3 Overflow Inlet Sizing
The proposed water quality BMP overflow inlets will be sized for the peak runoff flows produced
by the 100-year storm event. Sizing calculation will be provided to accompany the storm drain
plan set based on the weir or orifice equation.
3.1.4 Energy Dissipater Design
Runoff from the Drainage Basin 1000 will be conveyed to the proposed BMP and outlet to an
existing storm drain system and outfall into the Santa Gertrudis Creek (that was designed and
constructed per another plan set); therefore, no energy dissipation design for the storm drain outfall
is anticipated for this project, other than the BMP energy dissipation design, which will be
provided during the final engineering.
Prepared by: BH:JR:vs/C_RIV_G/Report/17883-H.004
Rick Engineering Company – Water Resources Division 4-16-21
Revised: 8-30-21
9
4.0 FLOOD CONTROL DETENTION ANALYSIS
As described in the introduction of this report, the project proposes one (1) BMP (basin) within
Drainage Basin 1000. In order to mitigate for anticipated increased runoff due to the proposed
development, a flood control detention analysis has been conducted for the 100 year 24 hour storm
event in accordance with County of Riverside requirements. Based on the additional volume
provided within the BMP, it is anticipated that the post-project un-detained peak flow rate will be
mitigated to the pre-project peak flow rate level (equal or less); therefore, an adverse impact to the
downstream storm drain system is not anticipated. . The following values were calculated utilizing
Hydrologic Modeling System (HEC-HMS) following guidance supplied by Riverside County
Flood Control (RCFC). Supporting calculations are included with Appendix 9 of this report.
For information regarding the Hydromodification Detention Analysis conducted for the project,
accomplishing detention of up to the 10-year design storm, please refer to the Project Water
Quality Management Plan.
Table 4.1 – Detention Summary for the 100-year Storm Event Discharging to SGC
Storm Event: 100 Year, 24 Hour
Pre-Project
Peak
Flowrate1,2
(cfs)
Undetained
Post-Project
Peak
Flowrate1,2
(cfs)
Detained
Post-Project
Peak
Flowrate1,2
(cfs)
PA 10 (Drainage Area 1000) 3.0 2.6 2.1
Note:
1: Calculated utilizing HEC-HMS per RCFC Guidance. Refer to Appendix 9 for supporting information.
2: cfs= cubic feet per second.
Prepared by: BH:JR:vs/C_RIV_G/Report/17883-H.004
Rick Engineering Company – Water Resources Division 4-16-21
Revised: 8-30-21
10
5.0 ROUGH GRADING BASIN
The permanent biofiltration basin has not been specifically designed to serve as a temporary
Sediment Basins or Sediment Trap; however, it is located at the low point on the site and may be
useful to serve as temporary sediment/storm water collection area during grading of the site. If this
area is used as part of the temporary erosion and sediment control BMP measures, it is important
that it is excavated and restored to the design subgrade elevations prior to installation of permanent
storm water BMP components. The principal outlet for the basin should be selected to convey
100% of the 100-year, 6-hour peak runoff from the drainage area in a mass graded condition
assuming the basin is full, and no incidental detention is provided. The 100-year, 6-hour peak
runoff from the drainage area in a mass graded condition is determined using a runoff coefficient
of 0.70 and assuming a Time of Concentration (Tc) of 10 minutes.
The temporary rough-graded basin will utilize a 48-inch (minimum) corrugated metal pipe (CMP)
riser for the principal outlet. Since the type of outflow through a riser (weir flow or orifice flow)
and the weir coefficient for weir flow vary depending on the amount of head (water depth) over the
riser crest elevation, a spreadsheet was utilized to calculate weir flow and orifice flow at
incremental depths above the riser crest. Weir coefficients were obtained from Figure 9-57,
Relationship of Circular Crest Coefficient C0 to H0/Rs for Different Approach Depths (aerated
nappe) [where H0 is head and Rs is the radius of the riser], from the Design of Small Dams
(United States Department of the Interior Bureau of Reclamation, 1987).
The total depth of the basin should be equal to the addition of the riser height, the head above the
riser crest elevation required to convey 100% of the 100-year, 6-hour peak runoff from the
drainage areas in a mass graded condition, and one foot (min.) of freeboard. Refer to Appendix 8
for a summary of the sizing calculations.
Prepared by: BH:JR:vs/C_RIV_G/Report/17883-H.004
Rick Engineering Company – Water Resources Division 4-16-21
Revised: 8-30-21
11
6.0 CONCLUSION
This drainage study presents the hydrologic and hydraulic analyses for the Wingsweep Property
Planning Area PA10. Hydrologic calculations were computed in accordance with the Riverside
County Flood Control and Water Conservation District - Hydrology Manual, dated April 1978
(manual). The Advanced Engineering Software (AES) 2014 Rational Method Analysis (Version
21.0) program was used for the rational method modeling in this study. The discharges for the 100-
year storm events have been calculated for proposed condition project site and storm drain sizes
have been determined based on the 100-year peak flow rates. It is understood that the current
drainage pattern is generally consistent with the drainage pattern that existed prior to mass-
grading.
In order to determine the detention volume required to reduce the post-project peak discharge rates
back to the pre-project peak discharge rates at the discharge point, a detention analysis has been
included with this drainage study.
Post-project flows will be treated per regional requirements. Please refer to the Water Quality
Management Plan (WQMP) for the project titled, “Water Quality Management Plan for
Wingsweep Property Planning Area 10 – Tract # 37925,” dated August 30, 2021 (and any
revisions thereafter), prepared by Rick Engineering Company (Job Number 17883H), for more
information on water quality and hydromodification detention.
Appendix 1
FEMA FIRMette
Note: A copy of the FEMA FIRMette is provided in this Appendix for as a reference; however, it
is important to note that the project is outside of the 100-year FEMA
floodplain/floodway limits
USGS The National Map: Orthoimagery. Data refreshed April, 2019.
National Flood Hazard Layer FIRMette
0 500 1,000 1,500 2,000250Feet
Ü
117°6'18.92"W
33°33'25.41"N
117°5'41.46"W 33°32'55.43"N
SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
SPECIAL FLOODHAZARD AR EAS
Without Base Flood Elevation (BFE)Zone A, V, A99With BFE or Depth Zone AE, AO, AH, VE, AR
Regulator y Floodway
0.2% Annual Chance Flood Hazard, Areasof 1% annual chance flood with averagedepth less than one foot or with drainageareas of less than one square mile Zone X
Future Conditions 1% AnnualChance Flood Hazard Zone XArea with Reduced Flood Risk due toLevee. See Notes.Zone X
Area with Flood Risk due to Levee Zone D
NO SCREE N Area of Minimal Flood Hazard Zone X
Area of Undetermined Flood Hazard Zone D
Channel, Culver t, or Storm SewerLevee, Dike, or Floodwall
Cross Sections with 1% Annual Chance17.5 Water Surface ElevationCoastal Transect
Coastal Transect BaselineProfile BaselineHydrographic Feature
Base Flood Elevation Line (BFE)
Effective LOMRs
Limit of StudyJurisdiction Boundar y
Digital Data Available
No Digital Data Available
Unmapped
This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards
The flood hazard information is derived directly from theauthoritative NFHL web ser vices provided by FEMA. This mapwas exported on 4/24/2020 at 6:09:17 PM and does notreflect changes or amendments subsequent to this date andtime. The NFHL and effective information may change orbecome superseded by new data over time.
This map image is void if the one or more of the following mapelements do not appear: basemap imagery, flood zone labels,legend, scale bar, map creation date, community identifiers,FIRM panel number, and FIRM effective date. Map images forunmapped and unmodernized areas cannot be used forregulatory purposes.
Legend
OTHER AREAS OFFLOOD HAZARD
OTHER AREAS
GENERALSTRUCTURES
OTHERFEATURES
MAP PANELS
8
1:6,000
B 20.2
The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative proper ty location.
Appendix 2
Hydrologic Backup Information
Includes:
1. Rainfall Intensity Chart D-4.1
2. A tabulation of parameters assigned to AES calculations & Runoff coefficient Supporting
Calculations
3. Web Soils Survey
Note: Please refer to following page for example of
typical AES entry parameters to calculate C value
Typical AES Entry Parameters for Software to Calculate C Values
(Refer to Plate D-5.6 of RCFC Hydrology Manual for Land Use Description)
Western Riverside Area, California
RaD2—Ramona sandy loam, 8 to 15 percent slopes, eroded
Map Unit Setting
National map unit symbol: hcy9
Elevation: 250 to 3,500 feet
Mean annual precipitation: 10 to 20 inches
Mean annual air temperature: 63 degrees F
Frost-free period: 230 to 320 days
Farmland classification: Not prime farmland
Map Unit Composition
Ramona and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of
the mapunit.
Description of Ramona
Setting
Landform: Alluvial fans, terraces
Landform position (three-dimensional): Tread
Down-slope shape: Concave, linear
Across-slope shape: Linear
Parent material: Alluvium derived from granite
Typical profile
H1 - 0 to 14 inches: sandy loam
H2 - 14 to 23 inches: fine sandy loam
H3 - 23 to 68 inches: sandy clay loam
H4 - 68 to 74 inches: gravelly sandy loam
Properties and qualities
Slope: 8 to 15 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat):
Moderately high (0.20 to 0.57 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 1 percent
Available water storage in profile: Moderate (about 8.1 inches)
Interpretive groups
Land capability classification (irrigated): 4e
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: C
Ecological site: LOAMY (1975) (R019XD029CA)
Hydric soil rating: No
Map Unit Description: Ramona sandy loam, 8 to 15 percent slopes, eroded---Western
Riverside Area, California
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
4/17/2020
Page 1 of 2
Note: The hydrologic soil
group is shown as Type 'C"
per the Natural Resource
Conservation Service
(NRCS) Web Soil Survey.
However, due to the
compaction condition
resulting from the majority of
the site being previously
mass graded over a decade
ago, the site infiltration
capacity was understood to
be reduced. Therefore, for
the purpose of hydrologic
modeling, Type ‘D’ soils
were used to calculate runoff
coefficients. This would also
result in a more conservative
peak flow rate.
Minor Components
Hanford
Percent of map unit: 5 percent
Hydric soil rating: No
Greenfield
Percent of map unit: 5 percent
Hydric soil rating: No
Tujunga
Percent of map unit: 5 percent
Hydric soil rating: No
Data Source Information
Soil Survey Area: Western Riverside Area, California
Survey Area Data: Version 12, Sep 16, 2019
Map Unit Description: Ramona sandy loam, 8 to 15 percent slopes, eroded---Western
Riverside Area, California
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
4/17/2020
Page 2 of 2
Appendix 3
Drainage Study Map for Wingsweep Property Planning Area 10
(Pre-project)