There are many ways that a construction site can ensure that sediment does not reach our waterways. One of the most obvious that you can immediately see when you visit a site is inlet protection. The main types of inlet that you see on site are either a curb inlet or a grated drop inlet. You can choose from a variety of different ways to protect these inlets, but the basic idea is allowing the water to continue to flow through the stormwater system while also reducing the amount of sediment runoff that goes down the drain.
For grated inlets, the standard practice is to double wrap your grate with a filter fabric that will stop the sediment from getting through, and then surrounding the grate with some additional layer of filtration. Depending on the site, some may choose vegetative buffer around the inlet using sod, a gravel buffer using the appropriate sized rock and a screen to contain the rock, or a perimeter silt fence mounted around the inlet with wooden stakes and trenched into the ground. Materials to consider when designing your inlet protection can include:
- Filter fabric or filter bags
- Silt fence
- Sand bags
- Sod or other vegetation
Curb inlets, which consist of a catch basin and drain build into a curbside, usually have a standard method of protection. Often, a sock pipe, which is made with a corrugated pipe covered with a filter fabric sock, is simply placed along the curb. Some might choose to use a method such as sand or gravel bags, cement blocks, or other similar items to anchor the sock pipe in place to avoid displacement. Two anchor devices are placed at either end, with a third placed in the center between the curb and the sock pipe to create an overflow structure.
Sometimes it might be advisable to simply create a diversion barrier to direct the runoff to a designated area. This will only work if you are moving the water down an appropriate slope, are not creating a backwash effect, and have a designated sediment trap area in which the runoff has a chance to settle out.
Make sure that if you are in an area prone to flooding or are preparing for a large storm, that you remove your inlet protection. Blocking up your inlets can cause flooding, which may damage nearby equipment, machinery, or properties.
For consultation on your inlet protection needs, please be sure to contact KCI, and we would be happy to help you determine the best solution for your site!