NPDES / Erosion and Sedimentation Control Project
Erie County, PA

Grantee: Erie County Conservation District
Basin Program Funds: $15,000
Non-federal Funds: $8,499
Project Duration: 06/1998 - 06/1999
Status: complete

Problem Statement
Measurable increases in urban development in Erie County, Pennsylvania and changes to the state's National Pollution Discharge Elimination System (NPDES) permit process, created a need for public awareness of nonpoint source pollution and appropriate best management practices for both permitted and non-permitted earth disturbance sites.

Background
The Erie County Conservation District is developing a 35 acre environmental education park in Erie, Pennsylvania. "Headwaters Conservation Park" is located in the upper watershed of Mill Creek which discharges into Presque Isle Bay on Lake Erie. The park is an example of how conservation and industrial expansion can co-exist. Over its long term development, the park will be used to demonstrate a variety of conservation best management practices.

Activities
The NPDES/Erosion and Sedimentation Control Demonstration Project used a building site next to the park as an opportunity to demonstrate non-traditional best management practices (BMP) for nonpoint source pollution control during construction. The Conservation District modified a required storm water facility to serve as a sediment trap during the construction phase of the project with the assumption that sedimentation control would be more efficient, cost effective and timely. The project team then used the information gleaned to hold a NPDES workshop for local contractors, developers, engineers and municipal officials.

The project team developed a storm water management plan which was submitted for township approval. They determined the required capacity for the sedimentation trap and outlet structure. While awaiting approval of the storm water management plan, the team inspected the construction site weekly and installed temporary best management practices including a silt fence, vegetative buffers along the creek and filter strips.

Once the storm water management plan had been approved, the team excavated the sediment basin. Sedimentation basins capture and store eroded soil from effluent leaving a disturbed surface site before the water is discharged into the environment. The amount of sediment released is controlled by the basin's outlet structure. Working in conjunction with the University of Pennsylvania, Department of Agricultural and Biological Engineering, the project team installed a Faircloth skimmer as a temporary trap outlet device. Skimmers allow eroded material to settle to the bottom of a sedimentation basin while drawing out and releasing clean water. Project personnel dug an interceptor channel which diverted sediment-laden runoff from throughout the building site to the sedimentation trap. They also seeded and mulched the pond embankment and surrounding area.

The project team inspected the site weekly in order to monitor the basin's efficiency and ensure that the skimmer operated properly. They were also able to identify and correct problems as they arose. These included breaches to the diversion berm which required the construction of a separate, temporary trap.

The team developed an educational brochure outlining the project and how it applied to NPDES regulations for a best management practice (BMP) workshop. The workshop introduced township officials and engineers, as well as consultants and developers to a newly published manual, "Pennsylvania BMP Manual for Developing Areas." The workshop also addressed recent changes to the NPDES, use of multi-purpose BMPs, and a summary of the sedimentation basin project and findings.

Results
One of the goals of this project was to persuade developers to use non-traditional, mulitple use BMPs for projects involving earth disturbance. Within the first several months after the workshops two consultants expressed interest in obtaining a skimmer, and numerous plans submitted to the township have proposed using the required storm water pond as a temporary sediment trap during the construction phase.

Additionally, soil saving calculations for both the temporary sediment trap and the sedimentation basin indicate that the basin was much more efficient. The temporary sediment trap accumulated 20 tons of soil while approximately 31 tons of soil were displaced. This meant a net loss of 11 tons of soil. The sedimentation basin accumulated all but one ton of the 39 tons of soil diverted into the basin.

Contact: LeRoy Gross, (814) 796-4203

print-ready factsheet