Projects & Programs
Engineering Evaluation of Restoration Alternatives for Coney Island Creek, New York
KeySpan Energy contracted PNNL staff, while at another organization, for the Engineering Evaluation of Restoration Alternatives for Coney Island Creek adjacent to the former Brooklyn Borough Gas Works Sitein New York. This study included hydraulic modeling to evaluate the responses of flow regime and flushing characteristics in the creek to different creek restoration alternatives and outflow conditions.
Coney Island Creek is a narrow and shallow channel subject to tidal forcing at the mouth. The study area is approximately 2,700 ft. long and 200 ft. wide. The vertical water depth ranges from 1 ft. at the upstream end to 6 ft. near the mouth of the creek. A significant portion of the upstream channel becomes dry during low-tide because of the shallow water depth in upstream. The dominant forcing for the hydrodynamic processes in the creek are semi-diurnal tides varying from 2.7 to 8.3 ft. In wet seasons, strong inflows from combined sewer overflow (CSO) and storm drains may influence the circulation pattern and water quality in the creek.
A one-dimentional transient model for the Coney Island Creek using Environmental Protection Agency stormwater management model (SWMM) Extran Block was set up. The SWMM Extran Block is designed for simulation of dynamic flows and pollutant through the sewer, drainage, or open channel system. The model was forced by tidal elevation at the downstream open boundary. The wetting and drying process during a tidal cycle in the upstream of the creek was successfully simulated in the model. The model was calibrated and verified against observed water surface elevations and velocities.
Project Highlights:
- Developed a hydrodynamic model to simulate tidal flushing
- Evaluated CSO and storm drain effects on creek water quality
- Evaluated/completed restoration of a creek next to a former gas works site.