Beaver Creek Flood Control Dam Rehabilitation Project

Beaver Creek Flood Control Dam, located on Beaver Creek near Guthriesville, Chester County, is a flood control dam that provides reduction of flood waters for communities located along Beaver Creek, the East Branch Brandywine Creek and the main stem of the Brandywine Creek. The dam was constructed in 1976 as part of the Brandywine Watershed Work Plan. This watershed-wide plan was developed in 1962 by the Chester County Water Resources Authority (CCWRA), Chester County Board of Commissioners and the United States Department of Agriculture, Natural Resources Conservation Service (NRCS), in cooperation with other state and local partners.

With technical support and funding from NRCS, CCWRA will undertake a rehabilitation project on Beaver Creek Flood Control Dam starting in the summer of 2020 in order to meet modern dam safety standards and to extend the lifespan for another 50 years.

Following the rehabilitation project, Beaver Creek Flood Control Dam will transition back to a dry dam where the standing sediment pool will be eliminated and replaced with a naturalized stream channel with adjacent wetlands and wildlife habitats. These changes will improve flood control functions and safety, provide additional wildlife habitats, and improve the water quality of Beaver Creek. 

Rehabilitation Project Fact Sheet


BeaverCreekDam_RehabFactSheet This two-page fact sheet includes a description of the Beaver Creek Flood Control Dam, the benefits of the rehabilitation project, the components of the project, and the transition to a natural landscape.

Open House Meeting - July 22


BeaverCreekDam_OpenHouseAnnouncement CCWRA will be holding a public informational open house on Wed 7/22/20 from 6:00 pm – 8:00 pm at the East Brandywine Township building. This will include a series of informational displays that attendees can view. CCWRA staff be available to answer questions.
BeaverCreekDam_OpenHouseDisplays
Informational Displays

The informational displays for the July 22 Open House are posted here.

Beaver Creek Flood Control Dam provides flood protection for:


  • Approximately 4,330 residents 
  • 8 schools with a student population of 3,450 
  • Approximately 2,500 employees 
  • 1,770 properties with a combined assessed value of over $300 million.
Beaver Creek Dam
Beaver Creek Dam, Chester County, PA

Rehabilitation of the dam will provide many benefits ...


Flood
Protection
Flood protection will be improved for downstream communities and extended for another 50 years.
Dam
Safety
The dam will meet new dam safety standards that have been put in place since the dam was originally constructed.
Water
Quality
Removing the sediment pool will improve water quality of Beaver Creek, which is designated by the state as a “cold water fishery”.
Public
Safety
A public safety hazard will be eliminated by removal of 
the sediment pool.
Naturalized Wetlands and Wildlife Habitats Naturalized stream, wetlands and wildlife habitats will be re-established upstream of the dam, in place of the sediment pool.
Maintenance and 
Worker Safety
Dam maintenance needs will be reduced and safe access of maintenance crews to the riser will be provided.

Rehabilitation Project Components


Auxiliary 
Spillway



Drainage
Improvements



Riser and
Upstream Slope

Armoring the Auxiliary Spillway Control Section
To prevent erosion and failure of the auxiliary spillway during a major storm event, a roller compacted concrete (RCC) drop structure will be constructed at the auxiliary spillway control section. The RCC structure will be covered with soil and re-vegetated to maintain the grass cover.

Lowering the Crest Elevation of the Auxiliary Spillway
To meet dam safety regulations, the elevation of the auxiliary spillway crest will be lowered in order to safely pass the required design storm flows.
  Trench Drain System
A trench drain system will be installed to more efficiently collect and drain subsurface and surface water at the downstream embankment toe. 

Toe Drain Access
Beaver Creek Flood Control Dam was constructed with two internal drain pipes that discharge into the outlet of the dam.  A new vertical sweep extension of the internal drain will be installed within the embankment and additional clean-outs will be added to improve access to the existing drains.
  Dewatering of Sediment Pool
The sediment pool will be dewatered in the summer of 2020 as the first step of preparing the site for construction of the needed improvements.

Riser Structure Replacement 
The existing riser structure is currently misaligned. This will be replaced with a new riser immediately adjacent and upstream to the existing structure.

Upstream Slope Protection
A portion of the upstream face of the dam will have riprap installed to reduce erosion when the dam detains floodwaters.

Transition to a Natural Landscape



Following the construction of the components described above, CCWRA will transition the operation of the dam to a dry dam. This will maintain the dam’s existing flood control function by detaining flood waters and releasing them at a controlled rate over a period of days after the storm has ended.

The former sediment pool will be seeded with a native seed mix to stabilize the soil during the initial stages of the Rehabilitation Project. Upon completion of the Rehabilitation Project, additional seeding (as needed) with a native food and cover wetland seed mix will take place to permanently cover any areas that have not established permanent vegetative cover.

Beaver Creek Flood Control Dam was constructed from 1974 to 1976 and initially had a sediment pool until the end of 1976. The purpose of the existing sediment pool is to collect sediment from the upstream runoff. The permanent vegetative cover will provide equal or enhanced sediment removal. Beginning in late-1976, the sediment pool was drained until 1992 and the dam was operated as a dry dam with a mix of natural wetlands and meadows upstream of the dam. Since 1992, CCWRA has maintained a sediment pool which covers approximately eleven acres and has an average depth of two feet. The sediment pool is not open to public use or recreation and is not stocked with fish.

PostRehabRepresentation_Web
Photo representation of Beaver Creek Flood Control Dam following the rehabilitation project.

PostRehabRepresentation_Web
Beaver Creek Flood Control Dam: Flood basin with natural vegetation (1991)

Contact Information


For additional information regarding the Rehabilitation Project, please contact: 
Janet L. Bowers, P.G.
Executive Director
Chester County Water Resources Authority
ph: 610-344-5400
email: wauth@chesco.org