Reach Use Question

[martin888888]

We have a 50ac site that we are trying to do a pre-development analysis for. The site has 3 basins..

Basin 1 - Sheet flows to NE
Basin 2 - Sheet flows to SW
Basin 3 - Collected in a piped conveyance system and discharges to the SE.

Although the basins discharge at different points on the site all runoff eventually reaches a creek sitting about 300' to the east. To model the property you would create a subcatchment for each basin. Would you link all three to the same Reach or create a seperate reach for each subcatchment?

I think you would create a seperate reach for each since the flows are being combined at a point. You can then add the three flows to get your post development discharge.

Thanks

 

[psmart]

I'm not sure I understand your question. If all there subcatchments enter the the channel at the same point you would use a single reach. But if they enter at different points along the channel you could use three reaches in series. I would setup the reach layout according to the flows on the site.

Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[martin888888]

All three subcatchments will enter the channel (channel is offsite) at different location. One is point discharge, and the other two are sheet flow. Trying to analyze the pre-development flows just from the site and before the flows reach the channel. I beleive you would set up seperate reaches for each basin/subcatchment and then can put the reaches in series to get total flow leaving the site?

 

[psmart]

Yes, you could use multiple reaches in series. For details on reach modeling and use please see

http://www.hydrocad.net/reach.htm

Peter Smart
HydroCAD Software

http://www.hydrocad.net