Hello,
I just started using Hydraflow hydrograph and ran into a problem while setting up pond routing. Here is the situation
In my model I have a hydrograph (SCS method) routed through a pond. The outflow from the pond runs into a channel and which eventually combines with the outflows from other hydrograps downstream. The pond outflow is setup for an emergency spillway only which acts as independent structure (not multi-stage). My pond bottom elevation is set at 828.40 and emergency spillway elevation at 829.85. Pond storage is set by contours and the contour area is 98,483 SF. When I route tihs hydrograph through the pond, all values such as peak flow, peak time and Hydrgraph volume comes zero. See attached screen shot. Once I drop the emergency spillway elevation (let's say to 829.00) it will produces values. I don't understand is to why dropping emergency spillway elevation produce results since pond is sized to store all the volume for 1 and 2 year storm and very little is discharged but by dropping elevation produce more discharge which ultimately produce a result. Can someone explain please................
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Please see attached screen shot of requested Elevation vs time.
thanks
All of the water fits in the basin for those storm events, so the water isn't being discharged from the basin. The water in the basin goes to 829.38 feet. Once you lower the spillway below this elevation water is going to start flowing out of the spillway causing water to go into the chanel as you should be able to observe in the attached EL vs T graph.
Thanks for responding back and providing your input. The water flowing out of this pond goes into a channel which does not produce a result if pond spillway elevation is 829.85 It give me an error "Plotting error. Cannot plot". Instead if I drop the elevation as I had mentioned in my original post then the channel produce a result .Without eliminating this error I can't produce a report for the site combined hydographs.
Attached I have provided a screen shot of this error. I wasn't able to attach original file due to gpw extension. I can email this if an address is provided. I must also mention that this model is based on existingt site conditions for which I am trying to estimate current storage and runoff from the site.
Thanks a lot !
You CAN attach just about any file by just adding a new suffix like .txt to the file.
Bill
Don't forget to explain what you did.
Bill,
Thanks. I have attached the file with .txt extension. Please chnage to .gpw to access the file.
Thanks again for all your input and continuous help
No error in 2015 version.
Thanks Fred,
My company doesn't have 2015 yet. I have tried both in 2012 and 2013 and give me error. Any other way around it you might sugest.
thanks
Stupid programmer not checking for division by zero. Obviously oblivious to the regulatory nightmare us engineers face now a days. To get around this abonimation of code you'll want to provide a non-zero value when you do the reach. I did this by adding in a dummy small area and then adding the flow from it and the pond into the reach. This provides about 3 cf of water, but not anything that is going to change the overall calcs. I've attached what works.
You'r right, it's a glitch in the program. Thanks so much for looking into it and getting to the bottom of this problem.