By Brian Hartman // 2020-08-03
Temporary (temp) stabilization is any material or product that can be applied to disturbed ground and stockpiles, for erosion control protection. Temporary stabilization is intended to counteract the erosive influences of rain, snowmelt and wind. Without temp stabilization on disturbed areas, erosion and stormwater runoff are significantly more likely to occur. Erosion and stormwater runoff can lead to sediment build-up. Sediment can carry many pollutants which flow into the streets and eventually end up in our lakes, rivers, and wetlands via stormwater inlets. To help prevent direct runoff and erosion into these natural habitats, temp stabilization is applied adjacent to lakes, rivers, and wetlands.
There are many different types of temporary stabilization. On residential and commercial construction sites, the most common varieties include: hydromulch, straw mulch, disc anchored straw mulch, mats, and erosion blankets. Seeding disturbed ground for vegetative cover is another form of temp stabilization, as is rip-rap on disturbed areas adjacent to discharge points and outfalls. There are multiple factors that come into effect when deciding which type of temp stabilization is the correct one to use. Some of these factors include price, slope of land, type of soil, and expected weather.
The Minnesota Pollution Control Agency has specific regulations regarding temporary stabilization. These regulations are explained by the state under the Construction General Permit, or CGP. The primary regulation states that all disturbed areas must be stabilized when construction activity ceases for 14 days or more. Stabilization must be applied no later than 14 calendar days after the construction activity has ceased. If construction activity has permanently ceased on disturbed ground, permanent stabilization (sod) must be applied within 14 days. If construction activity has temporarily ceased on disturbed ground and will not start back up again for 14 days or more, temp stabilization must be applied within 14 days. If the site discharges water to special or impaired waters, the stabilization timeframe is 7 days.
Temporary stabilization is a key component in keeping our lakes, rivers, and wetlands free of pollution capable of being discharged from construction sites. The percent reduction of soil loss can range as high as 99% depending on the type of temp stabilization applied to the disturbed soil. Overall, temp stabilization is an imperative Best Management Practice to use on disturbed areas at all construction sites.