20 - Sewer HotspotsITEM NO. 20
Costa Mesa Sanitary District
Memorandum
To: Board of Directors
...an Independent Special District
From: Scott Carroll, General Manage
Date: July 31, 2013
Subject: Sewer Hotspots
Summary
Sewer hotspots are line segments that require higher cleaning frequencies (more than
once a year) due to large grease accumulation, structural defects, and /or root intrusion. In
the beginning of 2011, the District had 95 hotspot locations. As of today, the District has
successfully reduced the number of hotspot locations to 43 due to several actions
performed by staff that includes repairing structural defects, installing short liners and top
hat liners to prevent root intrusion and disseminating FOG awareness.
The Board has requested staff to analyze the practical number of hotspots and then report
back with our findings. Below are staff findings to this report.
Staff Recommendation
That the Board of Directors receive and file this report regarding the practical number of
sewer hotspots within CMSD service area.
Analysis
Strategic Goal No. 1.3 is to "Reduce Hot Spot locations to less than 40 ". Every quarter
(once every three months), District staff and consultant Environmental Engineering &
Contracting (EEC) analyze the causes for labeling line segments as hot spots and then the
group will determine a course of action to remedy line segments and remove them from
the hot spot list. Sample coursed of action include installing cured -in -place short liners and
top hats to eliminate root intrusion, repairing line segments and replacing pipes that have
sags.
The 43 hot spot locations are broken down into the following categories along with the
number of locations for each category:
ID Protecting our community's health and the environment by providing solid waste and sewer collection services.
www.crosdca.gov
Board of Directors
July 31, 2013
Page 2 of 3
Grease
20
Structural
3
Structural w/ roots
4
Structural w/ grease
10
Roots
5
Roots & Grease
1
On June 17, 2013, the hot spot quarterly meeting was held in which the group determined
that six hot spot locations can be added as a change order to Project #197, System Wide
Sewer Reconstruction — Phase III project. The six locations are broken down as follows:
Structural w/ Grease 2
Roots 3
Grease 1
When Project #197 is complete the District will have 37 remaining hot spot locations and
will achieve Strategic Goal No. 1.3. However, should the District stop at 37 hot spot
locations or should staff continue trying to reduce this number? What is the practical
number of hot spot locations?
Of the 37 locations there are four grease locations that currently have a nine month
frequency (cleaned once every nine months). The notes from these locations indicate light
FOG accumulation, which means after having a few more observations these four
locations could be moved to annual cleaning, thus being removed from the hot spot list. If
that would occur, the District would have 33 hot spots.
The remaining 15 grease locations will need continued source control activities to ensure
food service establishments (FSE) are implementing their best management practices for
FOG. If the District decides to step up its FOG enforcement procedures by increasing
inspection frequencies at FSE's than it's quite possible these locations can be removed
from the hot spot list. However, there are two locations that are high density residential.
Staff has disseminated FOG brochures to residents on Hamilton informing them about the
potential hazards for pouring grease down the drain (the brochures were done in Spanish
and English), but because these neighborhoods have high turnover it is very plausible that
grease will continue to accumulate in this area and will require high cleaning frequencies.
Therefore, staff believes it is practical to at least two grease hot spot locations will remain.
Structural hot spots are more difficult to remove because of repair cost. It may be more
economical and cost effective to clean a line segment twice a year than it is to repair or
rehabilitate it. Of the fifteen structural hot spots, staff identified three possible removal
because repairs have been completed and staff is currently monitoring these locations,
and another location has ductile iron pipe corrosion and will eventually need replacement.
Many structural hot spots have significant sags (some have multiple sags) and is cost
prohibitive to perform the repairs. Staff believes it is practical that six structural hot spots
will remain.
Board of Directors
July 31, 2013
Page 3 of 3
Of the two remaining hot spots with roots, one location can possibly be removed because
the roots are already cut on an annual basis. Staff will continue to monitor this location for
possible removal. Roots are being cut every six months at the other hot spot location.
Cost may be prohibitive to repairing this line. If it is, this hot spot location will remain.
CONCLUSION
Staff believes that it is practical to have a total of 9 to 11 hot spot locations. How long it
take to reduce the hot spot list from 43 to 9 or 11 is unknown at this time, but staff believes
11 hot spot locations should be the new new goal for Strategic Goal No. 1.3.
Strategic Plan Element & Goal
This item complies with Strategic Element 1.0., Sewer Infrastructure and Strategic Goal
No. 1.3., Reduce Hot Spot locations to less than 40.
Legal Review
Not applicable
Financial Review
Funds are budgeted appropriately to maintain the hot spot locations. As more hot spot
locations are reduced the staff hours spent on hot spots can be shifted to providing annual
cleaning services.
Public Notice Process
Copies of this report are on file and will be included with the entire agenda packet for the
July 31, 2013 Board of Directors regular meeting at District headquarters and on District's
website.
Alternative Actions
1. Direct staff to report back with more information.