detention basin invert elev
detention basin invert elev
(OP)
Where should the invert elevation of the pipe into a basin be set at? If its low, as the basin fills up, so will the pipe. Does this matter? Usually pipes are designed to flow full so I'm not saying the pipe can be used as additional storage but what are the considerations when determing the inlet invert elevation?





RE: detention basin invert elev
RE: detention basin invert elev
RE: detention basin invert elev
RE: detention basin invert elev
RE: detention basin invert elev
RE: detention basin invert elev
RE: detention basin invert elev
RE: detention basin invert elev
You add the sump (aka small permanent pool) to a pond by making the area where the inlet pipe comes in deeper than the rest of the pond. For example, the sump could be 2-5 feet (say pipe diameter + 2ft) deeper than the overall pond bottom and would have length and width dimensions at least 3x the inlet pipe diameter. Side slopes could be as steep as suitable for the soil characteristics(say around 2H:1V) and stabilized with rock over geotextile.
The point of a sump is that it would hold water, so that energy from incoming water is dampened by the backwater effect on the end of the inlet pipe, even when the "overall pond" is empty. Consider that if a sump is not provided, during the initial filling of the pond the incoming water will potentially scour the pond sides and bottom as the flow enters the facility.
You can tell if you need a sump by comparing the discharge velocity of the pipe to the erosive velocity for the pond bottom material. A sump is one way to reduce the velocity; another way is to control the pipe slope & design so that erosive velocities do not occur. A rock pad may also be acceptable.