Pennsylvania Water Science Center personnel remove broad-crested weir, Codorus Creek at Spring Grove
Spring Grove Weir Removal
Spring Creek Weir Removal Increases Aquatic Ecosystem Connectivity
Ensuring Recreational Safety
USGS Staff Cameron Ensor, Nick Grim, & Dylan Baumbach Prepare for Weir Removal
The weir removal was completed Summer 2021, in collaboration with U.S. Army Corps of Engineers.
The station was established in 1966 to measure gage height and discharge relative to upstream reservoirs. Although low-head dams and weirs appear innocuous, they create dangerous conditions for water recreation. Headwater behind the weir displays smooth and laminar subcritical flow conditions. As water crests and cascades over the structure, flow becomes supercritical, dramatically increasing in velocity and generating a hydraulic jump. At the downstream base of a low-head weir this produces strong recirculating backwater that can be impossible to escape, even for experienced swimmers or those wearing a personal flotation device. Weir removal ensures public safety while improving upstream hydrologic connectivity for aquatic biota.
The stilling well for water levels was updated with a pressure transducer to provide near-real-time stream discharge (flow) data, transmitted to the USGS National Water Information System every 15 minutes.