StormCalc – Essential Stormwater Tools

Name: StormCalc – Essential Stormwater Tools
Author: ashainp

Perform common stormwater calculations quickly using Rational Method, Tc, and Detention Volume tools.

As of June 2026, StormCalc – Essential Stormwater Tools has 12 users in the Productivity category.

ashainp Productivity

Chrome Web Store ↗.crx

Users+50.0%

Rating0%

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— reviews

Reviews0%

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Version

1.0.3

Manifest V3

History

4 snapshots

Tracking since Apr 17, 2026.

View as table

Date	Users	Rating	Reviews	Version
Apr 17, 2026	8	—	—	1.0.3
May 3, 2026	11	—	—	1.0.3
May 29, 2026	10	—	—	1.0.3
Jun 7, 2026	11	—	—	1.0.3
Now	12	—	—	1.0.3

Permissions & access

Permissions: None declared
Host access: None declared

Screenshots

StormCalc – Essential Stormwater Tools screenshot 1

StormCalc – Essential Stormwater Tools screenshot 2

StormCalc – Essential Stormwater Tools screenshot 3

StormCalc – Essential Stormwater Tools screenshot 4

StormCalc – Essential Stormwater Tools screenshot 5

About

StormCalc is your all-in-one toolkit for stormwater and dam volume calculations. Designed for civil and hydraulic engineers, consultants, and field practitioners, this tool streamlines common hydrological calculations into a single, easy-to-use Chrome extension 

Features:
Rational Method:
-Quickly estimate peak flow (Q) using runoff coefficient, intensity, and area.

Time of Concentration (Tc):
-Calculates Tc using the Bransby-Williams method with flexible unit inputs.

Detention Volume Calculator:
-Compares pre- and post-development scenarios with auto-generated hydrograph and required detention storage.

Manning’s Equation (NEW):
-Computes flow rate for both circular and rectangular pipes with built-in roughness coefficients.

Dam Volume Estimators:
-Quick Method
-Square Dam
-Circular Dam
-Gully Dam