Dam & Reservoir

Drag the two dam handles to set position, length & orientation. Adjust the height slider. Everything is computed in your browser.

⚠ Synthetic DEM. These are demo elevations, not real LiDAR. Re-run build/build_dem.py --real to bake the true USGS 3DEP surface.

Dam height: 10.0 ft

Dam length—

Crest elevation—

Reservoir

Storage—acre-ft

Flooded area—acres

Max depth—ft

Mean depth—ft

Release a drag (or move the slider) to finalize the 1 m shoreline, then export.

Assumptions & caveats

Pool assumed full to crest (WSE = lowest point under the dam + height). No freeboard.
LiDAR is bare-earth and cannot see under existing water, so the current pond's depth is missing — storage over open water is under-counted.
Ignores seepage, evaporation, sediment, and spillway/outlet works.
Nonsensical dam placements give nonsensical pools (expected). Watch for edge / abutment warnings.
Not a structural, hydrologic, or permitting analysis.
DEM: —