Page 6 - Vol40 No3 Sept-Oct2022

SPRINGFIELD By Ken Stewart, P.E., Amanda Dobbs, P.E., and Michael Burgett, P.E.
An Optimized Solution to Sanitary

Sewer Overflows and Capacity

The City of Springfield is well- From Reactive Repairs to Proactive which can be included in the city budget
positioned as a more sustainable, healthy Maintenance and anticipated well ahead of time.
community that protects the environment, To fully examine the city’s wastewater Gresham Smith also used the GIS
thanks to recent improvements that collection system, Gresham Smith and database to build a computerized hydraulic
prevent a yearly average of 100 sanitary SWWD reviewed existing data and model of the wastewater collection system,
sewer overflows. conducted field investigations, using which was utilized to assess current
After 10 years of research, planning and manhole inspections, smoke testing, flow flows, evaluate improvement projects and
construction, the renewed, comprehensive monitoring, rainfall data and closed-circuit plan expansions for future growth and
wastewater collection system is increasing TV monitoring. This enabled the team development. Following the assessment
capacity and providing Springfield with to pinpoint critical areas where blockage and modeling, Gresham Smith determined
strategies for long-term success. Led by occurred, locate cross connections and that the best approach to reducing
Nashville, Tennessee-based Gresham assess the overall physical degradation of overflows was a systemwide program
Smith, the program involved seven sewer the system. Input from SWWD staff and focused on three core areas—rehabilitation,
rehabilitation projects, the construction field personnel also was crucial to the conveyance and storage—that could be
of two new wastewater storage tanks, and program, as they were able to identify areas implemented in phases. This combination
improvements to 40 miles of public sewer that consistently experienced operational of remediation methods proved the best
lines. and maintenance issues. solution because it reduces rainfall-induced
Aging Infrastructure Creates During the process, the team recognized flows into the system, maximizes system
storage and improves system capacity while
Challenges SWWD’s need for a GIS-centric database minimizing costs to the utility.
Aging and in need of repair, to house the physical data from the
Springfield’s existing sanitary sewer sewer pipes, record drawings, reported Starting With Sewer System
system was experiencing significant overflows, manhole inspection reports Rehabilitation
sanitary sewer overflows. The Springfield and photographs, rainfall data and sewer- The first phase of the program called for
Water and Wastewater Department flow monitoring data. The resulting GIS seven sewer rehabilitation projects, which
(SWWD) reported more than 400 database now forms the basis of a long- revitalized the wastewater collection
overflows to the Tennessee Department term asset management program, allowing and transmission system by correcting
of Environment and Conservation the city to shift from reactive repairs to deficiencies in the system structure
(TDEC) during a five-year period. With proactive maintenance and replacement,
the ultimate goal of eliminating sanitary
sewer overflows, the city entered an
Administrative Order on Consent (AOC)
with the United States Environmental
Protection Agency (EPA), which required
the City of Springfield to develop
and implement a variety of plans and
programs.
Even though the City of Springfield
was required to comply with the AOC,
maintenance of the wastewater collection
system was delegated to the Springfield
Water and Wastewater Department, which
retained Gresham Smith. As a team, the
three parties established the Springfield
Overflow Abatement Program, which
involved assessing and designing the
necessary infrastructure improvements,
overseeing construction and
environmental compliance, and analyzing
the results to determine if further action
should be taken.

6 TPW September/October 2022