Beginning in 1997, several of the Canal’s water purveyors reported increased concentrations of total suspended solids in raw water during and immediately after precipitation events, requiring increased chemical use for treatment and increasing residual sludge generation. A 1999 study by the United States Geological Survey (USGS) reported that turbidity did not decrease in the Canal reach between Ten Mile Lock and the Route 18 spillway in New Brunswick. The USGS study found twelve “infalls” to the Canal; however, none were known point sources of treated or untreated effluent to the Canal – the problem apparently is caused entirely by nonpoint source pollution. There are no NJDEP water quality monitoring stations located on the Canal, and thus NJDEP does not include it in the integrated list that identifies water bodies that do not meet water quality standards.

In 2001, NJWSA received Section 319(h) Clean Water Act funding from NJDEP to complete the “Delaware & Raritan Canal Tributary Assessment and Nonpoint Source Management Study”. Project partners included Franklin Township (Somerset County) and South Bound Brook Borough. Princeton Hydro and SWM Consulting provided technical assistance. The project, which focused on the final eleven miles of the water supply portion of the Canal, identified 73 stormwater infalls to the D&R Canal. NJWSA and Princeton Hydro used a WinSLAMM model to estimate pollutant loads; the model indicated that 75% of the total sediment load was produced by ten infalls. Princeton Hydro identified priority areas for implementation and provided general recommendations for the location of potential projects. The final plan, which was the first study that NJDEP approved as a watershed restoration plan, did not include specific implementation recommendations as is required for nine-minimum element watershed restoration plans that are prepared today.

To this day, multiple projects have been implemented within the targeted priority areas including the following major activities:

• Installation of a USGS monitoring station at Landing Lane in order to calibrate the WinSLAMM model
• Installation of Filterra units adjacent to existing storm drains and a baffle box to reduce sediment loads in South Bound Brook.
• Retrofit of a dry detention basin in partnership with the Rutgers Preparatory School.
• Installation of a rain garden to treat runoff from Quail Brook in partnership with the Somerset Park Commission and Quail Brook Golf Course.
• Several rain barrel workshops were conducted for residents of Franklin Township
• Basin retrofits including concrete low flow channels in Laird Terrace, Gauguin Way, Renoir Way, and Municipal Complex in Somerset County.

The D&R Canal Nonpoint Source Project began in 2001 and will continue into the future. Multiple partners have collaborated over more than two decades to implement projects that protect the Canal as a water supply resource. Funding sources include NJWSA’s source water protection fund, NJDEP Section 319(h) and watershed restoration grant funding, DRCC stormwater mitigation funding and in-kind staff time from multiple organizations. To learn more about the evolution of this project, navigate to https://www.raritanbasin.org/canal-nps