time of concentration
time of concentration
(OP)
I wanted to know if this is an acceptable practice.
I have a small watershed (1.4 Ac) with a proposed gravel road in the middle. I am using a ditch turnout/level spreader to divert runoff from the roadside ditch to a forested area. I would like to run my Tc for the watershed from an upslope area down to the ditch, through the ditch, across the level spreader and through the forested area to my Point of Interest.
My question: Is it acceptable to enter the Tc as sheet flow below the level spreader?
I have a small watershed (1.4 Ac) with a proposed gravel road in the middle. I am using a ditch turnout/level spreader to divert runoff from the roadside ditch to a forested area. I would like to run my Tc for the watershed from an upslope area down to the ditch, through the ditch, across the level spreader and through the forested area to my Point of Interest.
My question: Is it acceptable to enter the Tc as sheet flow below the level spreader?





RE: time of concentration
RE: time of concentration
I figured that might be the case. I am designing a well pad with an access road. I have one watershed in the pre-construction condition and I am splitting the watershed in two for the post; one for the pad which is being treated by a BMP and one which contains the roadway with the roadside ditch and turnout. With the BMP for the pad I am reducing the runoff for all storm events above the 2-year event. For the 2-year event I have a 0.05 cfs increase which appears to be coming from the road. I am sure the level spreader below the turnout will account for this increase. I was just trying to avoid splitting the watershed again to model the level spreader given the small increase. In years past we wouldn't worry about such small increases.
RE: time of concentration
RE: time of concentration
Peter Smart
HydroCAD Software
www.hydrocad.net
RE: time of concentration
RE: time of concentration
I guess the answer is that the program defaults to two decimals and we've never really looked into whether that can be changed. Looking last night I saw how I can do that. Now I just need to talk my head engineer into letting me do it.
RE: time of concentration
Back to your question, definately chat woith the reviewer but go in with an sound approach.
RE: time of concentration
RE: time of concentration
Displaying runoff to nearest tenth...is just right.