HydroComplete is built by Michael Flynn, a practicing water-resources PE — and a lot of what gets built here is given away. GIS plugins, CAD libraries, and hydrology engines, all with the same rule as the paid product: real formulas, shown in full, no black boxes.
GPL / MIT licensed. Use them at work today.Draw an area of interest and get the composite curve number: SSURGO soils, NLCD land cover, DEM slope for dual hydrologic groups, and NOAA Atlas 14 design-storm runoff — all fetched automatically from federal services (CONUS). Outputs CN polygons, a per-cell CN raster, and audit-ready CSVs. Falls back to ESA WorldCover when the federal land-cover server is down.
One file per routine, named for the command it adds. No installers, no license servers.
Small AutoLISP commands for daily drafting: acreage labels, bearing-distance, slope labels, flatten, coordinate exports, and more.
Survey-first LISP for Carlson: lot bearing-distance, point renumbering, inverse, traverse, field-book reports, station labels.
Importable VBA modules for OpenRoads Designer: acreage labels, PNEZD point I/O, station-offset, level translation, Z tools.
The stormwater connector that reads pipe networks and catchments straight from your drawing. Free to use; Pro PDF export is paid.
Native-Rust storm sewer hydrology and hydraulics engine — Rational flows, Manning capacity, HGL stepping — built for embedding.
Rational method, SCS runoff, Manning's equation, HGL steps — the building blocks, implemented plainly and tested.
Pip-installable dam-breach hydrograph generator for SWMM / PCSWMM. Froehlich (2008) implemented, Teton validation case included.
Physics-based vortex particle simulation as a Manning's-equation alternative for open-channel scour screening. 109 tests.
Want the full design suite — detention routing, water quality, sediment, sealable reports? That's the paid product that funds all of this: HydroComplete Pro.