Watershed Mode Calibration 2

[ALTIME]

Hi All,

I used Eaglepoint Watershed modeling for our stormwater management design. Somehow the local regulartory agency thought our predevelopment flow rate is higher compared to the established value in the vicinity of our project land, and asked us to do model calibration with the nearby stream gauge with a gross drainage area of 1889 square km; while our land is only 64 ha. I'm wondering if I can do a calibration with this gauge flow information.

Any Thoughts?

Altime

 

[SMIAH]

I don't use it neither to be honest

 

[ALTIME]

Thank you for all your inputs. The local regulatory agency thought my predevelopment rate is higher compared to the established value in the regional drainage basin (3500 km2) stormwater management study. As some of you pointed out that the number 1.2 cm/s I got seems lower instead of higher. I used the regression equation developed in the study to validate my number to 0.75 cm/s, and it's still greater than my postdevelopment controlled discharge rate. So I think I'm ok to get the approval. The comparison of different models is just for my own information, and I'm willing to lean a free software like EPA SWMM to do the design work.

 

[RWF7437]

Please answer just one question....where are you , in the U.S. ?

 

[RWF7437]

http://hhwq.blogspot.com/

 

[ALTIME]

No, RWF7437, I'm in Canada.

 

[RWF7437]

Thank you for the answer ALTIME.

There is a Canadian counterpart to NOAA but the name escapes me at the moment. There was an earlier thread on this, I believe.

For most projects I find the reasonably priced HydroCad sufficient and a lot less arcane than SWMM, Basins, or HEWC-HMS.

good luck

 

[RWF7437]

http://www.climate.weatheroffice.ec.gc.ca/climateData/canada_e.html

 

[ALTIME]

Thank you RWF7437 for sheding light on this issue.

 

[puzzler77]

SMIAH:
From your post dated 4 Sep 09 15:36 concerning getting a 24 hour depth from an IDF curve just multiply the 24 hour intensity by 24 hours. Don't forget to convert to seconds to keep the units consistant (1 hour = 3600 seconds). Ironically, the IDF curves were developed from maps of 6 hour, 12 hour & 24 hour depth. Should a 6 hour depth be required, multiply the 6 hour intensity by 6 hours.

 

[RWF7437]

Smiah,
If you're lucky enough to have IDF curves that actually extend to 24 hours you could use Puzzler's suggestions. If not, you can take advantage of an additional 30 to 40 years of record and go to:

http://www.weather.gov/oh/hdsc/

good luck