HomeMy WebLinkAboutCT 02-07; EMERALD POINT ESTATES; EMERALD POINTE WATER SYSTEM; 2005-06-08,I 06/08/2005 10: 09 FAX 7604380_ DEXTE~ WILSON ENG ~002 C\ ".
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DEXTER WILSON ENGINEERING, INC.
-
June 8,2005
Hunsaker & Associates
10179 Huennekens Street
San Diego, CA 92121-2973
Attention: Ray Marin, P:r:oject Manager
Subject: Emerald Pointe Water System
:: 1 2
DEXTER S. WILSON, P.E.
ANDREW M. OVEN, P.E.
STEPHEN M. NIELSEN, P.E.
DIANE H. SHAUGHNESSY. P.E.
RECEIVED
JUN 23 2005
ENG\N~ER~ oe,PARTMt.:NT
509-001
As requested. we have analyzed the ability of the proposed water system to serve 14
residential lots along Sapphire Court, west of Cobblestone Drive. These lots a:r:e
Pl'oposed to be served from the Carlsbad Municipal Water District by connecting' to an
8-inch 550 Zone water line at the intersection of Sapphire Ddve/Cobblestone Drive
and extending an 8-inch line in Sapphire Court.
The District's 550 Zone is formed by pressu:re l'educing of the 700 Zone system. The
550 Zone pressure reducing stations are identified as South Point D an.d Point D #2.
Based on Table 6 of the Districts October 1997 Master Plan, the typical bycb:aulic
grade line in t.he 550 Zone system is 446 feet. This value was used to evaluate the
proposed water system.
Based on pad elevations along Sapphire Court ranging from 242 to 252 feet, the
maximwn static water pressure range fol' water service to these lots is 129 toIB3 psi.
Hydraulic calculations wete prepared and attached to this letter to verify that the
requirements of City Standards Section 8.2.2.:8 will be met. The critical scenario is to
verify if the system can maintain a minimum residual pressure of 20 psi during a
maximum day demand plus fire flow scenario. The attached calculation indicates that
for a fire flow of 1,500 gpm and an assumed source hydraulic g.radelirte of 446 feet, the
residual pressure at the l)lOst remote fire hydrant along Sapphire CouX't is 71 psi
703 PALOMAR AIRPORT ROAO. SUITE sao • CARLSBAC, CA ~2009 • ("leo) 439·4422 • FAX (700) 438·0173
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< 06/08/2005 10:10 FAX 7604380~ DEXTE~ WILSON ENG III 003 . . .
Ray Martin
Ju.ne 8, 2005
Page 2
during a maximum day demand plus fire flow event. We conservatively assumed the
entire fire flow to be a.t the end of the cul~de-sac.
Based on the :r:esults of our analysis, we believe that the proposed water system will
provide adequate wate;r,' service to the Emerald Pointe development along Sapphire
Court. If you have any questions or require additional information, please let us know.
Dexter Wilson Engineering, Inc-
Stephen M. Nielsen
SMN:ae
DEXTER WiL.SON ENGINe:e:RING, INC. PAGE 2
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SUBJEC.T
'06/08/2005 10:10 FAX 76043801~ DEXTE~ WILSON ENG ~006 .:. I • ,
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B. Hydraulic analysi$ of the System (Dynamio Pressures) shall address the following
requirements:
1. Under peak hour demand and no fire flow, minimum pressure should be no less
than 40 psi and not exceed 3.5 feet/1,000 ft. head loss in the pipe. Maximum
desirable head loss shall be 5.0 feetJ1,OOO ft. of pipe and maximum allowable
head loss shall be no greater than 10 feet/1 ,000 feet of pipe at peak flow.
2. Under maximum day demand plus fire flow, pressure in the system should not be
less than 20 psi for the period of the fire incident (assume tank to be half full).
During fire, pumps should be assumed to be off and the fire flow requirement is
to be delivered 100% from storage tanks.
3. The maximum desired pressure drop between static pressures and dynamic
pressur.es is 25 psi.
4. At least two sOlJrces of water from t\Yo different streets should be available for
each development (i.e., looped). Two sources from the senne transmission line
are acceptable if source from a different street is unavailable. No dead-end
systems are permitted, unless district's staff agree to it Looped systems are
required as described above.
5. Dead-end water lines are to serve nO more than 18 residences. A looped water
line is requIred for 19 or more residences.
6. No more than one fire hydrant on a dead-end line. Minimum line size shall be
8-inches.
7. Approved double cheCk detector assemblies (DeDAs) are required for all flre
sprinkler systems. This is particularly important for schools and commercial
developments.
8. Dynamic pressures shall" be analyzed with reservoir levels half full.
3.2.3 Water Master elan Pli!aking factors
Average Day Demand (ADD)
Maximum Month Demand (MMO)
Maximum Day Demand (MDD)
Peak Hour Demand (PHD)
1.0
1.5xADD
1.65 x ADD
2.90 x ADD
3.3 LOCATION, TYPE AND SIZE OF WATER FACILITIES
3.3.1 Distribution Mains
Distribution mains shall be 8~inch to and including 12-inch in size and shall be Class 150 or
Class 200, as shown on the plan, polyvinyl chloride (PVC) AWWA C-900 type pipeline.
3.3.2 Transmission ,Mains
Transmission mains shall be 14winch and larger In size and shall be either (PVC) AWWA C-905,
or steel pipeline and shall require Engineer's approval of type .w:iJ;[ to design of system.