Sourced runoff calculations
Rational and SCS / NRCS curve number with C from land cover, i from Atlas 14, A from the parcel — each term carrying its provenance.
// Consulting engineers
Numbers that hold in review.
Capital planning and design review live or die on whether the numbers survive scrutiny. StormwaterIQ automates the slog — terrain, rainfall, routing — using the same methods you'd pull from a drainage manual, and shows its work on every result.
// Design storm · Atlas 14
2-yr1.1″10-yr2.0″25-yr2.5″100-yr3.4″
Q=C·i·A
C0.85NLCD land cover
i4.18 in/hrNOAA Atlas 14
A2.34 acParcel polygon
Tc18 minTR-55 / Kirpich
// Peak flow0.00 cfsEach term carries its source · re-runs reproduce
01 — The gap
The method isn't the bottleneck. The plumbing is.
Pulling Atlas 14 intensities, intersecting land cover for C, delineating the contributing area, threading it through a model, then re-doing it for the next alternative — that's where the week goes. The Rational Method hasn't changed in a century; the data wrangling around it should.
02 — What you get
The whole job, in one place.
One model answers the questions this work actually asks — with the methodology shown on every number, so the output survives review.
Automated delineation
Drainage basins, flow paths, and time-of-concentration derived from terrain instead of hand-drawn over a contour map.
Alternatives in parallel
Test design scenarios side by side — pre/post comparison and detention sizing — instead of re-running one model at a time.
Reproducible by design
Re-run the same inputs against the same dataset and get the same answer. Every output is built to be auditable.
Reviewer-ready exhibits
Engineering exhibits and reports export in the formats your reviewers expect — with the methodology attached.
Defensible, not a black box
Method, inputs, data-source version, and citation travel with each number — so it stands up when someone asks how you got it.
Automate the wrangling. Keep the engineer's judgment.Built for consulting & design engineers