All About The Combined Sewage Overflow (CSO) PROJECT
The CSO Problem:
Combined Sewage Overflows are devices designed to discharge untreated
wastewater is into our waterways in wet weather.
Combined sewer systems collect storm-water runoff, domestic sewage, and
industrial wastewater and convey them to a treatment facility. During wet weather
the combined flow can exceed the capacity of the conveyance system or
wastewater treatment facilities activating the CSOs.
waterbodies, swimmers, boaters, waders. (*)
- CSO discharges contain disease causing organisms,measured as
enterococcus, fecal coliform, and e.coli.
- These organisms can cause intestinal illness in recreational users of the
The City of Bayonne has 28 CSOs, more than any local municipality. (*)
NJ municipalities are required to plan and execute CSO alternatives in order to be
in compliance with the Federal Clean Water Act, managed by NJ Dept of
These plans are coming due:
The Development and Evaluation of Alternatives Report is due on July 1, 2019.
The Selection and Implementation of Alternatives Report is due to NJDEP by
due June 1, 2020.
Solving the Problem:
Opportunities for Green Infrastructure
From the NJ Department of Environmental Protection.
"CSO permittees (municipalities) will need to
- reduce flooding,
- ensure proper operation, maintenance and management of existing
- provide opportunities for green infrastructure."
The NEA "encourages permittee and community collaboration on the planning and
development of projects that will provide urban redevelopment opportunities,
improve water quality, beautify neighborhoods, and improve the overall quality of
life in our urban communities. (*)
From NJ Clean Waterways
The Clean Waterways, Healthy Neighborhoods initiative is coordinating public
information for Bayonne and area municipalities.
A wide range of technologies and alternatives will be evaluated to analyze ways
to reduce the impacts of CSOs. This evaluation will consider the practical and
technical feasibility of each alternative while considering adherence to regulatory
compliance; cost effectiveness; ability to relieve flooding; non-monetary factors
such as implementability and operational considerations; and public acceptance.
There are a variety of GRAY (construction based) and GREEN (ecology-
MPNA joins our local Sierra Club and the Bayonne Nature Club to say
Identifying and advocating for Green Infrastructure solutions is our focus.
GREEN SOLUTIONS from NJ Future website
Pervious pavement systems
Paved surfaces that allow stormwater to infiltrate into an underlying stone layer
that stores it and allows it to seep slowly into the ground. With the installation of an
underdrain system, these systems can be used in areas where infiltration is limited
and will still filter pollutants and provide storage, but will not infiltrate the runoff.
There are three types of pervious pavement systems: pervious concrete, porous
asphalt, and interlocking permeable pavers.
Pervious surfaces (also known as porous or permeable surfaces) allow water to
percolate into the soil to filter out pollutants and recharge the water table.
Examples include planting beds, mulched beds, gravel, permeable pavers,
pervious asphalt, forested areas, and meadows. Turf and lawns are pervious, but
generally much less so than the above-mentioned surfaces. Solid surfaces that do
not allow water to penetrate, forcing it to run off, are called impervious or
impermeable. Examples include traditional asphalt, concrete, brick or stone, and
City of Philadelphia example HERE
Street tree trench
A linear stormwater management feature, typically placed near sidewalks, that
combines trees with an underground stormwater management system. On the
surface, it looks like a regular tree with a drain, but an underground stormwater
system manages and reduces runoff to provide additional stormwater management.
See City of Lancaster's tree trench study HERE
Detailed Construction info and case studies of
Minnesota Tree trenches.HERE
Bioswales (Rain Gardens)
Landscape features that convey stormwater from one location to another while
removing pollutants and allowing water to infiltrate. Bioswales are often designed
for larger-scale sites where water needs time to move and infiltrate slowly into the
ground. Much like rain garden systems, bioswales can also be designed with an
underdrain pipe that allows excess water to discharge to the nearest catch basin
or existing stormwater system.
Rain gardens, or bioretention systems, are landscaped, shallow depressions that
capture, filter, and infiltrate stormwater runoff. Rain gardens remove nonpoint
source pollutants from stormwater runoff while recharging groundwater. Rain
gardens serve as a functional system to capture, filter, and infiltrate stormwater
runoff at the source while being aesthetically pleasing.
Generally 55-gallon barrels that are placed under a gutter’s downspout, which are
used to collect rainwater from roofs. The stored water can then be used for
watering gardens, washing vehicles, or other non-potable uses.
Vegetated structures that are built into the
sidewalk to intercept stormwater runoff from the
sidewalk or roadway.
Stormwater planters, like rain gardens, are a
type of bioretention system. This means many
of these planters are designed to allow
the water to infiltrate into the ground. However,
some are designed simply to filter the water and
convey it back into the storm sewer system via an underdrain system.
A stormwater management approach that incorporates vegetation (perennials,
shrubs, trees), soil, and engineered systems (e.g., permeable pavements) to slow,
filter, and cleanse stormwater runoff from impervious surfaces such as streets and
sidewalks. Green streets are designed to capture rainwater at its source, where
rain falls, whereas, a traditional street is designed to direct stormwater runoff from
impervious surfaces into storm sewer systems (gutters, drains, pipes) that
discharge directly into surface waters, rivers, and streams.
Roofing surfaces that are partly or completely covered with vegetation. Green
roofs provide stormwater management by slowing down rainfall runoff and by
allowing a portion of the precipitation to be returned to the atmosphere through
Green roofs also reduce heat islands.
This action awards points for the installation of green roofs. Green roof systems
capture stormwater runoff, improve air and water quality, reduce the urban heat
island effect, provide aesthetic benefits, and extend the life of roofing materials.
Downspout planter boxes
Open-topped containers made of sturdy materials and consisting of soil media with
plants that provide an opportunity to reuse rooftop runoff. Although small, these
systems have some capacity to store rooftop runoff during rainfall events and
release it slowly back into the storm sewer system through an overflow.
COMBATING THE NEGATIVE GREEN INFRASTRUCTURE MYTHS
see NJ Future's fact list on these arguments HERE