HomeMy WebLinkAboutAgenda Statement 1973/08/07 Item 16+'
AGENDA ITEM N0. [ 16 ]
CHULA VISTA CITY COUNCIL MEETING OF: August 7, 1973
ITEM TITLE: Resolution - Approving the Use of Memorial Parka, as a Storm
Water Retention Basin
INITIATED BY:
BACKGROUND
Director of Public Works/City Engineer ~---
The Engineering Division has investigated the feasibility of using the
retention basin concept along the Central Basin as a mean to provide
flood protection at reduced cost. The action of a retent`on basin is to
control the maximum volume of storm water flowing past a iven point in
a drainage system.
Attached is a complete copy of the study. The important ~oints of the
study are summarized below.
1. Recommendation: It is recommended that Memorial Park be used as
a retention basin. The park's location, topography, stor ge capacity and
land use makes it well suited for such use. Through avai ability of
retention capacity at this location, the peak flow in the Central Basin
just west of 4th Avenue would be reduced from 737 cubic f et per second
(CFS) to 446 CFS.
It is further proposed that sluice gates be installe on an interim
basis to regulate the flow through two existing 54" calve is crossing 4th
Avenue near the park until such time that downstream drai age facilities
are improved to accommodate a reduced flow based upon the unrestricted
capacity of the twin 54" culverts (446 CFS).
Therefore there would be two phases involved in the progr m. First, use
of control gates to match downstream flow to the capacity of the greatest
restriction and second, the upgrading of downstream facilities so as to
ATTACHED: Resolution [X] Ordinance [ ](conti~~~~e~~l st~~
Report from Public Works - See EXHIBITLS
(in separate blue folder)
Financial Statement:
The estimated cost for the gates and appurtenant structur
of the existing stage building is $25,000 (proposed Capit
Project for FY74-75).
Commission-Board Recommendation:
N.A.
Department Head Recommendation:
Recommends adoption of resolution.
City Manager Recommendation: Recommend adoption
lem~~~l[ age)
[X] No. 1, 2
:s and rewiring
~1 Improvement
~CP
COUNCIL M~E"I'ING OF: August 7, 1973 AGENDA ITEM N0. 16+°~
Supplemental Page No. 2
i
accommodate the reduced flows shown in the report. I,
2. Memorial Park should be utilized as a flood water retention
basin because:
a. Flood protection will be provided to numerous downstream
properties along the Central Basin stream bed. ~
b. Probable damage to park facilities will be in requent and
minor in nature - expected to be less than $200 per ear.
c. Downstream improvement costs will be reduced.l~ A savings
in construction costs of $220,000 in both public and private
facilities is expected. Savings to public facilities alone is
expected at $148,200.
3. The use of flood gates is justified for the following reasons:
a. Flood protection for numerous downstream properties can be
provided by concentrating total damage to park facilities. However,
total damage to the park is likely to be far less th n the total
probable damage to downstream properties under any g~',iven flow
conditions. !,
b. Existing downstream facilities are so inadegl~iate in some
instances as to pose a threat of frequent flooding. ,.The flood
gates could substantially reduce the frequency and sjeverity of
flood damage downstream.
c. There is little likelihood that any signific'nt program of
upgrading downstream structures to either full or r stricted
capacity will occur within the next several years. Use of flood
gates will provide a means of minimizing downstreamldamage while
such a program is being developed.
The Director of Public Works will answer any questions o~ the Council.