Canal Tributary Assessment & NPS Management Plan,
Township & South Bound Brook Borough, Somerset County
Township, South Bound
project addresses nonpoint sources of pollution from influent
water sources to the Canal in the State Park and in the vicinity of
drinking water intakes.
New Jersey Water Supply Authority (NJWSA) and Franklin
Township have located and assessed the “infalls” to the
“infall” assessment included determining which ones
contribute the most pollutants and suspended sediment to the Canal
and development of conceptual approaches for the management of
nonpoint source loads. The consultants, Princeton
Hydro and SWM Consulting,
are preparing preliminary
designs of nonpoint source control best management practices.
Where necessary, resources beyond this 319(h) grant will be
sought to implement BMPs based on the nonpoint source pollution
project began with field reconnaissance to identify all infalls to
the Canal within the study area.
While a 1999 USGS study found twelve infalls within this
area, NJWSA identified 63 infalls.
Infall identification was complicated by the lack of a
comprehensive stormwater system map and the fact that portions of
the stormwater system are channeled underneath the Canal for
discharge into the Millstone River.
During the field reconnaissance, each infall was
photographed and located with GPS.
delineated the drainage area for each infall using Watershed
Analyst, an ArcView GIS extension.
Then the drainage area for each infall was field verified.
NJWSA and Princeton
Hydro/SWM Consulting entered NJDEP land use data into WinSlamm
(Source Loading and Management Model for Windows) to estimate the
sediment and phosphorus loads from each drainage area.
WinSlamm allows the user to divide each land use
(residential, commercial, industrial, open space, institutional
and freeway) into source areas (parking areas, roof, landscaped
areas, driveways, undeveloped, etc.).
The model then calculates how much of the pollutant load
originates from each land use and from each source area within the
drainage area for each rainfall event in the model run.
on the pollutant loads from WinSlamm, NJWSA and Princeton Hydro/SWM
ranked the infalls based on the unit (pounds per acre) and total
phosphorus and solids discharged from each infall (see attached
table of infall rankings).
Total solids, the primary concern of the study, were given
a weight of 1.0, total phosphorus was given a weight of 0.5, unit
solids were given a weight of 0.2 and unit phosphorus a weight of
A final ranking of infalls was then performed based on the
total number of points
(weighted points for total solids + total phosphorus+ unit
solids + unit phosphorus) each infall received.
Hydro/SWM are using the infall rankings to guide the development
of recommendations for BMPs.
They will begin with the top 10 infalls and develop
recommendations for as many infalls as funding allows.
to Basin Bulletin