WMS:OC Rational Equation: Difference between revisions

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where:
where:


* Q - peak flow (ft<sup>3</sup>/s or m<sup>3</sup>/s)
* Q &ndash; peak flow (ft<sup>3</sup>/s or m<sup>3</sup>/s)
* I - rainfall intensity (in/hr, mm/hr)
* I &ndash; rainfall intensity (in/hr, mm/hr)
* F<sub>m</sub>- maximum [[WMS:OC Losses|loss rate]], where F<sub>m</sub> = a<sub>p</sub> * F<sub>p</sub>
* F<sub>m</sub> &ndash; maximum [[WMS:OC Losses|loss rate]], where F<sub>m</sub> = a<sub>p</sub> * F<sub>p</sub>
* A - catchment area (acres)
* A &ndash; catchment area (acres)


This equation is very similar to the traditional [[WMS:Rational Method Equation|Rational Method equation]]. The term I - F<sub>m</sub> is often referred to as the effective precipitation.
This equation is very similar to the traditional [[WMS:Rational Method Equation|Rational Method equation]]. The term I - F<sub>m</sub> is often referred to as the effective precipitation.

Revision as of 20:05, 13 February 2013

Flows for the Orange County rational method are calculated from the following equation:

Q = 0.90(I - Fm)A

where:

  • Q – peak flow (ft3/s or m3/s)
  • I – rainfall intensity (in/hr, mm/hr)
  • Fm – maximum loss rate, where Fm = ap * Fp
  • A – catchment area (acres)

This equation is very similar to the traditional Rational Method equation. The term I - Fm is often referred to as the effective precipitation.


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