CSO Long-Term Control Plan Update/Integrated Plan
The existing collection system model will be updated using recent sewer data to be provided by
the City, including but not limited to as-built drawings, GIS data, and staff observations. This may
include refining tributary area delineations, updating invert or rim elevations, and/or updating
connectivity/configuration of the sewer system. The model’s parameters will be updated if needed
based on calibration/validation with temporary flow data collected in this task. Rainfall data will
be collected via permanent City gauges (3 total) and used in the calibration process.
Task 4 — Alternatives Analysis
Consultant will identify and evaluate a range of CSO reduction alternatives, including system
optimization, storage, treatment, sewer separation, and source controls. A range of CSO
alternatives will be evaluated between 0% and 100% CSO reductions (on an annual average basis)
using the sewer model. Knee of the curve evaluations (including costs) will be performed for the
alternatives.
Task 5 — Integrated Plan Framework
Consultant will perform Integrated Planning in accordance with the Water Infrastructure
Improvement Act which codified the 2012 EPA framework for integrated planning into the Clean
Water Act.
The overall purpose of the IP will be to assist Nashua in prioritizing and programming capital
improvements based on criteria most important to the municipality and the community. The IP
approach will result in a proposed capital schedule for a specified future planning horizon that
seeks to maximize benefits as early as possible based on the criteria, while also meeting all
requirements within the respective regulatory spectrum, including the Clean Water Act. The IP
will also result in integration and prioritization of capital projects for all applicable infrastructure
elements (wastewater and stormwater, and drinking water), thus eliminating a siloed approach to
capital project implementation.
Consultant will schedule workshops with City personnel to 1) facilitate the selection of preliminary
ranking criteria to be used for the triple bottom-line analysis, 2) develop guidelines and rules to be
used for inclusion and scoring of projects, 3) perform a preliminary importance ranking of selected
criteria, and 3) determine the preliminary list of projects and planning horizon timeframe from
which to base the integrated plan on.
Consultant will prepare a broad list of ranking criteria organized by environmental, social, and
economic categories as a first step. This list will serve as a reference only in the development of
the City’s criteria. An initial workshop will focus on environmental criteria and benefits to the
City, and then follow the same procedures for social and economic criteria. The result of the
workshop will be a working list of criteria to be used for the eventual scoring of capital projects.
This workshop will also include the preliminary discussion and development of project scoring
methods to be employed as the basis of the LTCP/IP. Consultant will describe the different
methods used and describe the preferred method (score-based quantification) in more detail.
An additional workshop will be conducted to determine the list of preliminary capital improvement
projects to be included in the integrated plan. Our understanding is that the list will include
wastewater, stormwater, and drinking water projects. The initial list will include those projects
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