Submitted to: National Watershed Conference National Watershed Coalition
Publication Type: Proceedings
Publication Acceptance Date: May 21, 1997
Publication Date: N/A
Interpretive Summary: Summary article; no new research reported; no interpretive summary required.
Technical Abstract: A two-dimensional physical model study was conducted of the Cedar Run Site 6, Fauquier County, Virginia, proposed roller compacted concrete stepped spillway and stilling basin. The purpose of the study was to evaluate the hydraulic performance of the stepped surfaces, effect of entrance abutments, adequacy of the stilling basin, and performance of a flip bucket. The proposed spillway is 106.7 m (350 ft) wide; the PMF peak discharge is 27.34 m**3/s/m (294 ft**3/s/ft); and the stilling basin design discharge is 18.31 m**3/s/m (197 ft**3/s/ft). A smooth chute was tested to permit comparison of the energy dissipation for the stepped surface with a conventional concrete surface. The steps were effective in dissipating energy. At the stilling basin design discharge, the energy dissipation with the steps was 33%, compared with 7.2% with the smooth surface. The stilling basin was very effective in dissipating energy at 18.31 m**3/s/m (197 ft**3/s/ft) and smaller discharges, and results showed it can be reduced 20-25% in length without negatively affecting performance. The flip bucket appears to be a viable alternative for use instead of the stilling basin.