Permanent Inlet Protection For Drop Inlet In A Gravel Parking Lot

[deactivated]

A reviewer has asked me to provide some permanent (not just temporary) inlet protection for a drop inlet that will be located at a low point in a gravel parking lot so that the drop inlet grate does not get clogged up with gravel. Is anyone aware of some solutions or has a link to a detail besides silt bag that is aesthetic and that would not require a lot of maintenance from the client? Thanks for your help.

 

[gbam]

I am not sure of the layout configuration without additional information; but could you: use a concrete apron or over excavate the area around the inlet so it has a small (4"-6" deep) sediment bay around the inlet?

 

[deactivated]

Basically, it is a "soup bowl" type of gravel detention basin that is 1 ft in height from top of drop inlet grate to highest point at the edge. See attached.

 

[BUGGAR]

I've seen birdcage like above grade drains like on roofs, but they had a guard post structure around them.

 

[gbam]

What Bugger describes is a trash rack. I presume that your drop inlet is a type 4 off roadway inlet (2'x3')with a grate. I would design a sediment forebay as it would be a cheap option.

 

[cvg]

if you are just worried about gravel plugging the grate, than make sure the grate is large enough so the gravel will go through. the inlet structure should have a sump at the bottom to catch the gravel and debris. a concrete apron is often used for erosion protection around grated inlets. if you have a lot of sediment moving, then you should either stabilize the gravel or reduce the depth and velocity of the flowing water so that it does not erode the gravel. that might mean more drainage inlets or flatter grades

 

[cneberly]

I will assume that the drop inlet is a grate at grade.
I often recommend a debris screen placed right under the grate.
see this diagram:

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1470606627/tips/Catchbasin_Model_CBS_-_w_Debris_Screen_Sizes_12_through_36_hgh80m.pdf[/url]

Chris Eberly, PE

http://www.parkusa.com