Loantaka Brook EPA Headwater Management and Restoration Plan

Loantaka Brook is the most significantly degraded tributary of the Great Swamp. The impaired water quality of the stream is the result of Nonpoint Source (NPS) pollution, in particular stormwater runoff high in levels of dissolved and particulate pollutants and sediments. Stormwater runoff has also created hydrologic and hydraulic impacts that has led to excessive stream bank erosion, loss of riparian vegetation, sedimentation, and channel scour. Complicating things further is the discharge of effluent from an approximate 1 million gallon per day sewage treatment plant

With funding from the USEPA, the Ten Towns Great Swamp Watershed Committee (TTC) hired Princeton Hydro to conduct a detailed study of Loantaka Brook with the goal of developing restoration concepts designed to improve the water quality and overall ecology of the stream.

The project had four main components:

• Collect and analyze stream water quality and flow data under both baseflow and storm event conditions,
• Quantify the pollutant load and hydrologic properties of the stream using a GIS-based diagnostic modeling approach,
• Identify a means of reducing the nutrient load of the effluent discharged from the Woodland STP, and,
• Correct stormwater runoff stream erosion problems in the headwater reaches of Loantaka Brook.

The project deliverables consisted of combining recent and historical data for the statistical analysis of the water quality database. This database enabled the TTC to document the existing status of the stream relative to both State standards and water criteria developed through the analysis specific for Loantaka Brook. The modeled pollutant and hydrologic data were used in concert with the field data to better identify, and subsequently target, NPS and storm flow related problems in need of management.

The project also yielded the conceptual design for a unique wetland system that would be used to reduce N and P loading generated from the STP. Concept plans were also developed for a number of stormwater Best Management Practices that would be used to retrofit existing stormwater conveyances for the purpose of reducing erosive flows and pollutant loading.