Water • Hydrology

Water Resources & Hydrology Calculators

Hydrologic estimation tools for rational method peak runoff, basin water balance, and reservoir storage retention.

Water Live Tool

Water Tank Storage Calculator

Size cylindrical and rectangular water storage tanks from dimensions or daily demand and residence time.

V = π/4 × D² × H · V = L × W × H
Water Live Tool

Water Demand & Flow Requirement Calculator

Estimate community or facility water demand (domestic, commercial, fire) and the design flow requirement for supply and storage sizing.

Q_design = P · q · peakFactor · Q_avg = V_daily / 86400
Water Live Tool

Tank Fill Time & Filling Rate Calculator

Calculate the time to fill a storage tank from a known filling rate, or the filling rate required to meet a target time.

t = V / Q · Q = V / t