HomeMy WebLinkAbout06.a. (Handout)(gandoO
Item 6.a.
Annual Report of
Sanitary Sewer Overflows
Curtis W. Swanson
Collection System Operations Department
February 16, 2012
Central Contra Costa Sanitary District
2011 Sanitary Sewer Overflows
➢37 overflows — lowest in CCCSD history
➢14% reduction in number of overflows
when compared to 2010; 41% reduction
in number of overflows when compared
to 2009
➢2.5 overflows per 100 miles
➢ No pumping station or wet - weather
capacity overflows
1
Overflow Quantities
Size of SSO (gallons)
Number
in 2011
Number
in 2010
Greater than or equal to 1,000
1
2
Between 100 and 999
9
13
Between 10 and 99
17
21
Less than 10
10
7
Total overflow volume
10,264 gallons
1 21,611 gallons
ME
Overflows Comparison
1999-2011
NambW d &Vwf m
200 lot - - Lowest in
143 141 Central
150 138 -123 - - . San
1b0
107 history!
100 i - - -- - -- -------- - -- -- 73--- 81 - - -86 - - --- --
43 37
- -I
50 - - -- - -- - - -- - -- - --- --- -� - - -- - - - - --
-� - - �-- 1 -
0 rt +—+
1999 2000 2001 2002 2003 2004 2005 2008 2007 2008 2009 2010 2011
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Comparative Data for 2011
From State Database
➢ Statewide (CIWQS as of 02115112)
■ 5,005 overflows and total volume of 28,059,798 gallons
■ Average of 5.3 overflows per 100 miles
■ Average volume of 5,600 gallons per SSO for the year
➢ Region 2 — Bay Area (CIWQS as of 02115112)
■ 1,579 overflows and total volume of 17,498,684 gallons
■ Average of 9.0 overflows per 100 miles
■ Average volume of 11,000 gallons per SSO for the year
Overflow Causes
Cause of SSO
Number in
2011
Number in
2010
Roots
22
34
Grease
3
4
Debris (rags, rock, paper)
9
5
All other
3
0
K,
2011 Geographical Trends
Walnut Creek 8
Pleasant Hill 4
Orinde 10
Martinez 4
Leteyette 9
Diablo 1
Danville 1
Concord 1
Alamo 1
0 2 4 e B 10 12
Nufnber of Overkwe
2011 Overview
➢ 56 days without a single overflow during 2011
(27 days in 2010)
➢ "Quality Cleaning" philosophy and follow up with
CCTV quality assurance
➢ Increased scheduled cleaning frequencies
where significant material was removed
➢ Cleaned 4,242,243 feet of sewers
- M-0- I 'I'm
0
Overview
➢ New TV contract is focused on sewers in
Lamorinda area.
➢ "Smart Cover" device successfully prevented
an overflow in Clyde area
➢ Engineering continued projects to
rehabilitate sewers — more focus on lines
with overflows and sewer lines on frequent
cleaning cycles.
—M--E
Recommendation
➢Accept 2011 Sanitary Sewer Overflows
Report
BCD_
41
Questions?
ME
0