Lake Luxembourg and Core Creek Dredging and Habitat Restoration

Princeton Hydro has worked with the Bucks County Department of Parks and Recreation on a continued effort to implement agricultural Best Managment Practices (BMPs) throughout the watershed, including seeking and obtaining funds through the USEPA Nonpoint Source Pollution Program (319). The funds have been used for five stream bank and shoreline stabilization projects within the Core Creek County Park, as well as a number of small retrofits to remove phosphorus from stormwater, additional vegetative shoreline buffers with the aid of students from Neshaminy Middle School, and a pocket wetland BMP to continue to reduce the total phosphorous (TP) loads entering the lake.

Most recently, Princeton Hydro and Bucks County embarked on an ambitious project to restore the inlet area of the lake, termed the Conservation Pool, into a naturalized stormwater treatment facility. This 17-acre forebay area had filled in with sediment over the decades and had limited capacity to treat the nutrient rich inflowing water. Using nature as a guide, Princeton Hydro designed and implemented a plan to dredge 15,000 cubic yards of phosphorus-rich sediment. Additionally, an emergent wetland system was designed and installation has begun to better retain sediment and phosphorus before it reaches the main body of the lake. This system includes infrastructure to ensure the ongoing maintenance and functionality of this BMP.

Beginning in July 2022, Bucks County lowered the water surface of Lake Luxembourg, as well as the conservation pool, and began the process of removing accumulated sediment. Bucks County contracted with Flyway Construction, and in August 2022 they mobilized to the site to prepare the County’s agricultural fields immediately adjacent to the pool to receive the dredged sediment while the water levels dropped. The sediment removal from the conservation pool was to restore the intended design function of a forebay and sediment collection location prior to it entering the main lake.

The restoration included the removal of just under 20,000 cubic yards of sediment and the placement of the highly organic sediment in the adjacent fields for dewatering and soil amendment. The sediment removal focused on the discharge of Core Creek into the Conservation Pool extending downstream of the additional tributary to the existing osprey platform. Nature-based habitat features such as log habitat and evergreen tree vanes were installed through the work area and conservation pool. In addition to providing habitat and refuge for wildlife, these features reduce the velocity of the water and promote sedimentation. The removal of sediment increases the depth of the water column which results in minimized potential for SAVs, decreased water temperature, and improved water quality.

In the Spring and Summer of 2023, the contractor will return to till the dewatered sediments and apply a nutrient fixing seed mix, as well as any soil amendments recommended by PSU Cooperative Extension, to improve the agricultural production of future crops. They will plant the areas that were not dredged, as well as the banks with native vegetation, to further provide habitat and promote sedimentation and nutrient uptake from accumulated sediments.