I am designing a wetland style pond and need to keep the total water inundation time under 72 hours during a 100 year event in order to not kill the plants. The site is about 10 acres and the pond is only about 2-2.5' deep. Using TR-20 with a Huff rainfall distribution, my total time is over 80...
I am designing a parking lot and the contractor wants to use recycled asphalt. What are the negatives to using this? I assume that the parking lot may not last as long but are their any other concerns? If it matters, I live in the midwest with some pretty cold winters.
I have read that the Time Interval needs to be less than 20% the time to peak. Is this correct? If so, I assume that means 20% of the time to peak of the Unit Hydrograph. Can anyone confirm my statement?
I have always been a bit confused as to how to develop a proposed Time of Concetration in which to model detention. Most of the work my firm does are small (~5 acres commercial sites). Most time of concetration models assume all water is channeled directly to the pond. For instance, TR-55...
I need to provide the existing 100-year peak discharge from a 5 acre site. To do this, I usually use the SCS-Type II,24 hr. rainfall distribution in Hydraflow. Using=Cn:80,Tc=15, and 7.58in. rain.....I get a peak discharge of 28.82 cfs.
However, I need to provide the peak rainfall using the...
I am a fairly new user to Hydraflow. I usually use the default shape factor of 484. I realize this number would go up or down based on my environment. However, I live in the midwest, so I figured that the 484 number would be ok.
What I need to know is how this number is figured. Is there a...
FOR A NORMAL SANITARY SEWER, I NORMALLY SPEC. A PVC PIPE ACCORDING TO ASTM D-3034 WITH ASTM D-3212 JOINTS. HOWEVER, WHEN CLOSE TO A WATER MAIN, I HAVE BEEN TOLD THAT I CAN USE THE SPEC ASTM D-2241 WITH ASTM D-3139 JOINTS FOR LOW PRESSURE APPLICATIONS. HOWEVER,WHEN I LOOK AT THE ASTM SPEC.,IT...
