Clay,

 

We have prepared a quick sensitivity analysis of the 100-year downstream starting conditions of Rawhide Creek in an effort to eliminate additional analysis of the Arapaho stormsewer
system. Attached is a profile comparing two different starting water-surface elevations. The first water-surface elevation is based on inlet control of 3-48" CMPs (minimum elevation
that could occur). The second water-surface elevation is set 4.05 feet above the top of the on-grade rail crossing at Midway Road. The starting water-surface elevation would need to
exceed this elevation before changes in the model would occur at the downstream property limits of the site.  It is highly unlikely that floodwater would exceed this elevation before
being conveyed overland. 

 

The sensitivity analysis demonstrates the starting cross-section is placed far enough downstream to eliminate fluctuations in the computed water-surface elevations at the upstream design
points (Bankston Collision Center). We are more then willing to proceed with the downstream analysis of the Arapaho Stormsewer System should the Town feels it is still necessary.  Please
advise...

 

Regards,

 

 
D. Ryan Plasse, P.E., CFM 
Director of Water Resources
 
 
8350 N. Central Expwy, Suite 1000
Dallas, Texas 75206 -1612
P: 972.235.3031 | F: 972.235.9544