Detention Basin Volume for a Target Time
The basin volume required to hold flow for a target detention time.
Example
You enter
- Target detention time (min) 120
- Flow (GPM) 350
You get
- Tank volume (gal) 42000
- Tank volume (ft³) 5614.58
Checked against published worked examples from: Ten States Standards / USEPA.
Details, formula, and sources
Scopevolume = target minutes x flow. 120 min of contact at 350 GPM needs 42,000 gal. Sizes chlorine-contact, flocculation, and sedimentation basins. Ten States Standards; the reviewing authority governs.
Formula or tableRequired volume = target detention time × flow (the inverse of detention time = volume / flow). Sizes chlorine-contact (CT), flocculation, and sedimentation basins to a target contact/detention time.
Source and editionRecommended Standards for Water Works (Ten States Standards), latest edition, by name. EPA Surface Water Treatment Rule (SWTR) 40 CFR 141 Subpart H by section for CT.
Free access40 CFR 141 free at ecfr.gov. Ten States Standards published by the Great Lakes - Upper Mississippi River Board.
What governsEstimate. Operator of record and primacy agency govern.
API field namestarget_minutes, flow_gpm, tank_volume_gal, tank_volume_ft3
- Plug-flow assumption returns the theoretical volume; apply a baffling/T_10 factor for CT creditEPA Disinfection Profiling Guidance