HomeMy WebLinkAbout16 - Big Canyon Reservoir Sediment DisposalJune 27, 2000
CITY COUNCIL AGENDA
ITEM NO. 16
TO: Mayor and Members of the City Council
FROM: Public Works Department
SUBJECT: BIG CANYON RESERVOIR SEDIMENT DISPOSAL
RECOMMENDATIONS:
1. Authorize the retention of the firm of Burns and McDonnell to manage the disposal
of sediment from the Big Canyon Reservoir site for $25,370.
2. Authorize contracting with hauling and disposal firms for the disposal of the
sediment from the Big Canyon Reservoir site for $28,800.
DISCUSSION:
The City's water distribution system includes the 200 million - gallon Big Canyon
Reservior. This reservoir is uncovered and sediment accumulates in the bottom. Every
three to five years the reservoir is drained so the sediment can be removed and the
lining can be inspected and repaired. This process is necessary to maintain the quality
of the water supplied to the City's system. In April of this year the reservoir was taken
out of service for cleaning. Approximately 900 tons of sediment was removed and
stock piled at the site.
Chemical tests taken on samples from the sediment indicated that it contained levels of
copper higher than the local landfills will allow. Alternate disposal sites were
investigated and a recycling center in Arizona was found to be the most feasible
disposal site. The City is required to coordinate the disposal of materials that can not
be taken to local landfills with the Orange County Health Department (OCHD).
The OCHD processing, site disposal management, hauling, and disposal require
expertise not currently available on the City staff. Waste management and disposal is a
specialized field. A proposal has been received from Burns and McDonnell to manage
the disposal of the sediment from the reservoir site to the recycling center and
coordinating the work with OCHD. The total price for this service is $25,370. Three
hauling firms have submitted quotes for hauling the sediment from the site to the
recycling center. The low price of $28,800 is from Rust & Sons Trucking. Three quotes
were received for the recycling or disposal of the sediment. Sonas Earth Sciences
quoted $20 per ton ($18,000 for 900 tons) to accept this sediment. Funds to cover the
SUBJECT: Authorization to Dispose of Sediment at Big Canyon Reservoir
June 27, 2000
Page 2
cost of the disposal project are available in the Maintenance and Repair Account
#5500 -8160 from the Utilities Water Division operating budget for this year.
The copper in the sediment comes from the copper sulfate that is periodically used in
the reservoir to control the growth of algae. This compound is commonly used in open
reservoirs across the nation to arrest algae blooms. It usually takes several treatments
during the year to control the algae. Over the years the copper accumulates in the
sediment from this treatment process. The City tests the copper levels in the water to
assure that the levels do not exceed the maximum standard of one part per million.
Our tests show we have maintained our copper levels below this maximum. When the
reservoir is covered, algae blooms will not occur and the copper sulfate treatment will
no longer be needed. Also, sediment from air borne dust will no longer be entering the
reservoir.
It is recommended that the firms of Burns and McDonnell, Rust & Sons Trucking, and
Sonas Earth Sciences be retained to perform respective necessary services to dispose
of the sediment at Big Canyon Reservoir.
Respectfully submitt pd,
PUBLIC WORKS DEPARTMENT
Don Webb, Director
By: _//Z
Tod Eldon Davidson
Utilities Services Manager
F: \Users\PBW\ Shared\ COUNCIL \Fy99- 00\June -27 \Sediment at Big Canyon Res.doc