WMS:OC Rational Sub-area Data

When setting up a Orange County Rational Method simulation, data must be entered for each sub-area.

• Area – The sub-area area (acres or ha.) can be automatically computed when using a DEM or TIN

• % Nonmountainous and % Mountainous – The percentage of the sub-area that lies below and above 2000 ft, respectively.

Use the Compute % Mountainous button to calculate these values using a DEM or TIN.

Initial Sub-area

• $T_{c}$ – The time of concentration (min)
• Intensity – The rainfall intensity (in/hr) is automatically computed based on the $T_{c}$

Losses

• $a_{p}$ – Pervious area percentage
• $F_{p}$ – Pervious area loss rate
• $F_{m}$ – Maximum area loss rate

Calculate $F_{m}$ by toggling on the Compute $F_{m}$ checkbox, entering values for $a_{p}$ and $F_{p}$, and using the Compute $F_{m}$ button or click on the Compute $F_{m}$ – GIS button to use GIS data.

Related Topics

• Losses
• Initial Sub-area Time of Concentration
• Orange County Rational Equation
• Orange County Rational Method
• Reach Routing
• Creating Watershed Models