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Project Site:
COSTCO PLAZA
La Quinta, CA
Prepared for:
COSTCO WHOLESALE COMPANY
999 Lake Drive
Issaquah, WA 98027
Project Manager:
Bob Strong, P.E.
Date Prepared: May 2095
JN: 156.93.07
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Prepared by:
ENGINEERING
16795 Von Karman Avenue, Suite 100
Irvine, CA 92606
(949) 474-1960
www.fuscoe.com
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Hydrology /Hydraulic Report April 2005
TABLE OF CONTENTS
1.0 PROJECT DESCRIPTION ............................ ..............................1
1.1 Existing Conditions ........................................ ............................... 1
1.2 Proposed Development ................................... ............................... 1
2.0 BASIS FOR DESIGN ................................... ..............................2
3.0 PROPOSED STORM DRAIN FACILITATES . ..............................3
4.0 RESULTS AND CONCLUSIONS .................. ............................... 3
5.0 APPENDICES ............................................... ..............................4
Appendix 1 - Site Hydrology .................................... ............................... 4
Appendix 2 - Site Hydrology Map (pocket) ..... 4
Prepared by: 1
Fuscoe Engineering, Inc.
16795 Von Karman Avenue, Suite 100
Irvine, California 92606
(949) 474 -1960
(949) 474- 5315.(fax)
156.9301 Costco La Quinta
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Hydrology /Hydraulic Report April 2005
156.9301
Costco Plaza
City of La Quinta
Project Number:
156.93.01
Supervising Engineer:
Bob Strong
RCE No. 28300
Date Prepared:
April 2005
Costco La Qu i nta
Hydrology /Hydraulic Report April 2005
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1.0 PROJECT DESCRIPTION
1.1 Existing Conditions
The project site is approximately 27 acres located near the southwest corner of
Jefferson Street and Highway 111.
The site is presently undeveloped and is bounded on the east by an undeveloped
parcel in the City of Indio, -on the west by an undeveloped parcel, on the north by
Highway 111 and on the south by La Quinta Evacuation Channel.
The site drains in a southerly direction to the channel where the flow enters the
channel from the top and continues northerly in the channel to White Water River
approximately 2500' to the north.
1.2 Proposed Development
The 27 acre site is proposed to include a Costco, other retail buildings and
associated parking facilities.
156.9301 1 Costco La Quinta
Hydrology /Hydraulic Report April 2005
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12.0 BASIS FOR DESIGN
The basis for design of the storm drain system includes analyzing the natural
condition and proposed development using the 100 year design storm per the
County of Riverside Hydrology Manual.
The site storm drain system will be designed to convey the 100 year storm with the
building finished floors elevated above the 100 year flood elevation.
Per discussions with Coachella Valley Water District, owners of La Quinta
Evacuation Channel, detention of flow will not be required on site. The site storm
drain system will outlet directly to the channel.
156.9301 2 Costco La Quinta
Hydrology /Hydraulic Report April 2005
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13.0 PROPOSED STORM DRAIN FACILITATES
The site storm drain system will be designed to intercept flow from the parking areas
and building and convey the flow to the existing La Quinta Evacuation Channel.
Storm water will be filtered using a CDS unit, or similar structure, prior to release
into the existing channel.
.0 RESULTS AND CONCLUSIONS
The building will be protected from 100 year flows. All site flows will discharge
directly to the La Quinta Evacuation Channel using a conventional system of pipe
and inlets.
156.9301 3 Costco La Quinta
Hydrology /Hydraulic Report April 2005
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15.0 APPENDICES
Appendix 1 - Site Hydrology
Appendix 2 - Site Hydrology Map (pocket)
401
156.9301 4 Costco La Quinta
COMPONENT AREA NUMBER
ACREAGE
Q1 CO FLOW (CFS)- 100 YEAR FREQUENCY
CFS CUBIC FOOT PER SECOND
--"a- FLOW DIRECTION
HYDROLOGY NODE
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