Name and Location:
Gwinnett County Find-and-Fix; Gwinnett County, GA
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Architect or Engineer:
Gwinnett County Department of Public Works
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Contract Amount:
$11 million
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Completion Date:
August 2005
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Services Provided:
CIPP and miscellaneous rehabilitative measures
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Total Project:
Completed 220 point repairs on 8-inch to 24-inch mainline; reset 27 frames and covers;
replaced 602 frames and covers; adjusted/replaced 124 manholes; 146 WEKO Seals, 36-inch
to 60-inch; 35,000 LF CIPP, 8-inch to 24-inch; 875,000 LF TV inspection 8-inch to 72-inch
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Description:
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When Gwinnett County opted to use a find-and-fix approach to repairing inflow and infiltration
entering its collection system, the Reynolds' team set out to investigate and rehabilitate the
sewer system in predetermined basins.
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To obtain immediate results, the team used existing data, including GIS, previously collected data
and information from discussions with Gwinnett County field staff. The data enabled the project
team to show an almost immediate reduction in I/I.
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The rehab area was defined as sewers and manholes within the 100-year floodplain in four basins.
GIS was used to identify parts of the system that met these criteria and ultimately to compile maps
containing nearly 700 map tiles per set for field crews doing manhole and TV line inspections. The
field maps contained all of the facility IDs for the entire system, which are referenced in the
field inspections.
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As the data is collected, it is input into GBA Master Series, a facilities management application. A
defect prioritization matrix was concurrently created to organize the defects and ensure the largest
and most severe defects were targeted first and to allow for tracking of defects with lesser severity.
The county was interested in identifying defects and observing flow produced by these defects so that
I/I could be identified and tracked as the system is renewed.
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As the data is populated, GBA is used to generate work orders and track progress of the inspections. The
work order repairs included manhole rehabilitation, inserts and resets, as well as sewer segment lining,
joint repairs and point repairs through excavation. In addition, manholes were located using survey
grade GPS to improve the accuracy of the county's sewer network.
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More than 875,000 feet of sewer and 3,380 manhole structures were investigated. The $11.0 million
dollar project identified 14.5 mgd of I/I and removed more than 9.3 mgd of that at an average cost of
$0.82 per gallon removed. Estimated annual savings are calculated to be nearly $3.5 million in
treatment costs.
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