HomeMy WebLinkAboutAgenda Report - February 3, 1982MEMORANDUM, City of Lodi, Public Wori:s Department
TO: City Manager
FROM: Public Works Director
DATE: January 13, 1982
SUBJECT: Lodi Lake
C
At a previous shirtsleeve meeting, Councilman Pinkerton in,uired about the
difficulty of preparing p:ans and specifications for the excavation or
deepening of Lodi Lake. it was understood that the p;irpose of the request
for Lake excavation was to increase the flow to the City's gro,indwater table.
From toe report completed fpril 1974 by The Spink Corporation to determine
the feasibility of keeping water in Lodi Lake on a year-round basis, the
fo:Iowing data was obtained:
Total aieo of lake - 36 acres
Average depth at center of lake - 7 feet
Ma.cimum depth - 12 feet
Volume - 250 acre feet
As part of this study, there were permeability tests taken at the locations
where additional fill embankment was recommended. Those tests showed that
permeability did increase as you went from a two -foot to a seven -foot depth
below the existing grade.
It is felt that if excavation is to be considered for the purpose of increas-
ing the flow of the groundwater table, that additional permeability tests should
be made in the actual lake bottom. Kleinfelder s Associates from `tockton
estimated the cost of taking and evaluating two permeability tests would be
approximately $650 to $700 (assuming testing equipment can be moved into and
out of the lake bottom).
in reviewing this matter with the Recreation b Parks Director, it is felt that
the center of the lake can be deepened, however, for safety and erosion
control, it is recommended that the sides remain relatively shallow as they
presently exist.
Prior to the Council requesting us to proceed further in this project, it
is felt that the following items should be considered:
COST
Based on deepening approximately 70% of the lake bottom proper
an additional two feet, there wound be approximately 80,000
cubic yards of excavation. Basea on $2.00 - $4.00 per cubic
yard, the approximate cost would be $160,000 to $320,000.
r
City Manager
January 13, 1982
Page 2
FUTURE LAKE PLANS -
if it is intended to ultimately keep water in the lake on a
ytar-round basis, this excavation may be detrimental since it
would increase permeability and would require additional water
pumping to keep the lake filled.
GROUNDWATER INFILTRATION -
The 1974 Spink report estimated, based on existing conditions,
seepage at 800 - 1,000 gallons per minute or one million gallons
per day. The actual groundwater flow and/or increase in flow
cannot be determined until permeability tests are actLIily taken.
FUTURE MAINTENANCE -
it is felt that approximately every two years additional minor
excavation of lake bottom would be required in order to main-
tain the same levet of permeability.
WATER QUAL I T! -
It is not -•nticipated that two feet of excavation will have
any effzct on water quality.
it is not our intent to do any additional work on this matter until specific
Council dire on s given.
6.ecreation
onsko
rks Director
b Parks Director
JLR/eeh