Beaver Dam Hydrology — Flood Attenuation & Wetland Formation

A cascade of three beaver dams sits along a modelled stream reach, each pond obeying a real water-balance equation: storm inflow fills the pond, a broad-crested-weir term lets water spill once it tops the dam crest, a linear leak term lets water seep through the loose stick structure at any level, and a Darcy-style seepage term pushes water sideways into the surrounding banks. That seepage accumulates in an aggregate water-table reservoir that slowly drains back into the channel as baseflow — the same mechanism, described in beaver-dam-analogue restoration studies, by which a simple channel becomes a wetland that both blunts flood peaks and keeps water flowing through dry spells. Adjust the dam crest height, bank permeability and storm intensity, trigger a storm pulse, and toggle the dams off entirely to see the undammed channel pass the same flood straight downstream.