Parking Lot Runoff and Erosion

[MER3]

I have a large parking area, probably 1 acre in total. It was built adjacent to a river and is supported by sheet piles in some spots. My problem is runoff related. We have storm drains installed in this parking lot that go directly to the river. I am trying to divert as much of the runoff as I can away from these drains because this gravel parking lot is a huge source of sediment in the runoff. As I divert water away from this parking area, I still have to deal with the water that does make it into the gravel. What are some techniques for controlling the amount of sediment that gets into the storm drains? We've done check dams in the past but they silt up pretty quickly around here.

 

[Twinkie]

If it is a gravel lot, and the gravel is your prime source of sediment in your inlets, I'm not sure there is much you can do to "prevent" it from getting into the inlets, short of paving the lot. Can you sump the boxes somehow, and fit the pipes with a snout.

 

[civilman72]

You could encourage the owner to do some sort of gravel surface stabilization (i.e. mag chloride), which will hold the binder in the gravel longer and decrease your sediment erosion and transport.

There aren't any methods that will not require some form of maintenance. Sumps in the inlets (with periodic cleaning) are most common for gravel parking lots in my area.

 

[beej67]

Tell the owner to use washed 57 stone?

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[mgvelkovich]

Have you considered using FlexStorm inlet filters? That could further assist in keeping sediment out of the storm drains.

 

[bimr]

Fabco makes inlet filters for this purpose, but of course there is maintenance involved.

http://www.fabco-industries.com/blo...aunch-pilot-partnership-using-fabco-products/

 

[LincolnPE]

Install the Snout in the inlets. The inlets have to be maintained by removing the sediment.

 

[IronDogg]

Sounds like you need one of these:
Link

They are expensive though, but a requirement for many new larger developments.

 

[ukbridge]

You could maybe install silt screens, however it is inevitable that sedimentation will occur over the design life of the drain. In designing/specifying a drain/culvert I typically neglect the capacity of the top 25% and bottom 25% of the pipe diameter.

The bottom 25% obviously assumes sediment, but the top 25% ensures freeboard conditions will occur in line with the flood I've designed for. This in line with the CIRIA document Design and Maintenance of Culverts which is widely used here in the UK.