To:
From:
Re:
Attachment:
C. Motion:
City of Nashua, Public Works Division
Board of Public Works Meeting Date: May 26, 2016
Stephen Dookran, P.E., City Engineer
Engineering Department
Wastewater Collection System Operation and Maintenance — Study
Proposed draft of Scope of Work
To approve the engineering contract for the Wastewater Collection System Operation and
Maintenance - Study to CDM/Smith of Manchester, NH in an amount not to exceed
$200,000. Funding will be through: Department: 169 - Wastewater; Fund: Wastewater;
Activity: CSO Consent Decree Projects.
Discussion: The city owns and operates almost 300 miles of sanitary and combined
sewers, some dating to the 1880’s. In addition, the separated drainage collection system
consists of diverse components including 138 miles of pipe which includes drain pipes,
culverts and catch basin laterals; 40 detention ponds, over 12,200 structures consisting of
drain manholes, catch basins and headwalls. The purpose of this study is to develop a
plan that is practicable and affordable to clean, repair and maintain the wastewater and
drainage collection systems so they can provide a maximum level of service.
Tasks to be completed during this study include reviewing the existing systems and their
inspection and maintenance programs, evaluating computer software (Cartegraph) usage,
reviewing existing budgets, developing a task list for system wide operation and
maintenance (O&M) prioritization of major rehabilitation based on risk and overlays on
other roadway assets and utilization, and developing an implementation schedule with
cost estimates and budgeting options. These sewer and drain systems are quite extensive.
They need a proper maintenance program in order to function in terms of flow, capacity,
extension of material life, prevention of flooding and reduction of CSOs. A large
percentage of the very old pipes totaling about 100 miles are at the end of their useful life
and some fail abruptly causing sinkholes and require high cost emergency repairs. These
pipes need to be identified and prioritized for rehabilitation. An O&M plan for the sewer
system is also required by the EPA and NHDES for the wastewater treatment discharge
permit as well as by the CSO Consent Decree. Regarding the drainage system, the
majority of stormwater management components have fallen into disrepair, and are no
longer effective and cause problems with flooding and erosion. An O&M plan is also
necessary and will be identified as a key point of the new MS4 permit.
A Request for Qualifications was emailed to ten engineering consulting firms and posted
on the City’s website. The following three firms submitted Qualification Statements on
April 28:
