PowerPoint Presentation

Headcut Prevention

CIVE 717: Assignment #4John Quebbeman, Andrew Steininger, Rachel WilliamsApril 12, 2012This presentation is presented in three sections:Headcut Equations- John QuebbemanPhysical Process and Model- Andrew SteiningerDesign and Prevention Methods- Rachel WilliamsHeadcut EquationsApril 12, 2012Headcut EquationsHydraulic EquationsSediment Transport EquationsNumerical Models (SITES)Empirical Quantification

Photo Source: WES Stream Investigation and Streambank Stabilization Handbook, US Army Corps of Engineers, October, 1997HydraulicsCritical Depth Occurs over top of headcutNormal Depth Commonly assumed for downstream channel below headcutUsed for Shear Stress CalculationsShear Stress Bed Shear used for determining transport capacity

hc=critical depthhn=normal depthV=velocityn=Manning Roughnessg=gravitational constantS=Friction Slopeh=depth=Specific WeightSediment TransportDownstream Erosion & Channel DeepeningSufficient Capacity to Transport Bed SedimentSupplyCritical DepthUpstream Advance & DeepeningChecks for Normal Depth Shear vs. Drop Shear

Normal Depth ShearDrop Depth ShearCheck for Maximum Shear:SITES Headcut AdvancementPhase III ErosionHeadcut advances upstream if threshold exceeded