I/I Studies
Hydraulic Modeling
Design & Construction
Operation & Maintenance
cMOM Compliance
Master Planning
Pipedream©
Georgia
Index: Dekalb County Gwinnett County
PROJECT: Development of Hydraulic Model
LOCATION: DeKalb
County, Georgia
SCHEDULE: September 1990 - June 1992
PROJECT
BACKGROUND:
DeKalb County retained the services of ADS Environmental Services to conduct a
comprehensive sewer system study of the East Snapfinger Basin in the South River Sewer
System. The system is tributary to the Snapfinger Water Quality Control Plant in South
DeKalb County. A total of 2.03 million feet of sanitary sewers were targeted for this
study. Its parameters included flow monitoring at 80 key locations and intensive surveying
to locate and quantify I/I in the collection system. Data collected from the sewer system
study included I/I defects identified from manhole and smoke testing, flow isolation, and
internal television inspection. Wade & Associates developed a calibrated
computer-simulated hydraulic model that the County hoped to use as the final model for
system maintenance and planning. The model was prepared to assess the relief and
replacement sewers required to safely transport remaining peak wastewater flows after
excessive I/I had been reduced through sewer rehabilitation.
PROJECT
SCOPE:
Wade & Associates compiled temporary flow monitoring data from 80 meter sites to
identify the relationship between peak flows and rainfall intensity. This relationship (Q
vs i) was then used to calibrate the defect hydraulic model for the 80 basins in the study
area. The model allowed the County to route rainfall-induced I/I hydrographs dynamically
through the entire system and investigate areas of overloaded sewers. I/I reduction
through cost-effective rehabilitation further allowed Wade & Associates to locate
necessary relief or replacement sewers and estimate the associated construction costs. To
optimize the relief sewer program, tolerable surcharge was determined from a detailed
computer-simulated hydraulic gradient analysis. The final model was delivered to the
County along with a recommendation for a $13.9 million relief sewer plan at an optimal I/I
reduction level of approximately 40%.
PROJECT:
Development of Hydraulic Model
LOCATION: Gwinnett County, Georgia
SCHEDULE: November 1990 - April 1992
PROJECT
BACKGROUND:
In 1990, Gwinnett County entered into a contract with ADS Environmental Services to
conduct a comprehensive sewer system study of Lawrenceville Area collection system. The
study included flow monitoring at 40 key locations and intensive surveys to locate and
quantify I/I in the collection system. A total of 573,000 feet of sanitary sewers were
targeted for this study. ADS retained Wade & Associates to assemble this information
into a calibrated hydraulic model used to project the number of relief and replacement
sewers required to transport remaining peak wastewater flows after excessive I/I had been
reduced through sewer rehabilitation.
PROJECT
SCOPE:
Wade & Associates compiled temporary flow monitoring data from 40 meter sites to
identify the relationship between peak flows and rainfall intensity. This relationship (Q
vs i) was used to calibrate the defect hydraulic model at each monitoring site. The model
allowed the County to route rainfall-induced I/I hydrographs dynamically through the
entire system and to investigate areas of overloaded sewers. I/I reduction through
cost-effective rehabilitation further allowed Wade & Associates to locate and estimate
the cost of constructing relief or replacement interceptor sewers. To optimize the relief
sewer program, tolerable surcharge was determined from a detailed computer-simulated
hydraulic gradient analysis. The final model was delivered to the County along with a
recommendation for a $3.0 million relief sewer plan.
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