Any contractor in Georgia that disturbs soil is required to go through training and testing to receive the proper certifications. All of our project managers have gone through this training to make sure our job sites don’t cause problems for the neighbors or the local environment. This guest post outlines some of the problems and solutions to dealing with stormwater runoff.
A refreshing shower or an impressive storm often rejuvenates the land—at least, they used to. Today, storms and other rainfall don’t always act as they should. Because of impervious surfaces—parking lots, roofs, and roads—plenty of precipitation doesn’t absorb into the ground.
So, what happens to it?
Rainwater that doesn’t absorb will flow along the ground towards a low point. Streets and parking lots are generally dirty surfaces. As the stormwater flows across that filth, it collects toxins and pollutants. And because there are fewer areas for the water to be absorbed, that toxic soup goes on to cause even more problems.
Stormwater surges overwhelm drain systems during heavy rains. So much water at a time can spill drains, leading to wastewater and sewage entering the environment.
If there aren’t any drains, that disgusting runoff eventually reaches natural waterways, like creeks and streams. If it’s located downriver of water processing plants, this pollution goes on to cause untold damage. From algae blooms to eroding stream banks, stormwater runoff creates a lot of danger.
Construction sites are often the first line of defense against runoff issues. House construction is no different. A stormwater runoff protection plan should always be in effect.
To help construction professionals, here are four crucial best management practices (BMPs) for stormwater runoff control.
Point best management practices function to capture runoff at specific “points.” Retention ponds and infiltration basins are two common examples. Designed to arrest and stop rainwater before it reaches waterways, point BMPs take many forms.
Larger construction sites benefit from the space to use wet ponds and surface sand filters. At a home construction site, options are more limited. However, several point-deployed solutions work great at a smaller site. These include:
- Rain barrels: Situated under downspouts, these collect runoff from roofs or other flat surfaces. Capturing this water prevents any debris from entering the environment. Once the waste settles, the water is reused for irrigation purposes.
- Cisterns: These are larger rain barrels holding up to 20,000 gallons. Because of the bigger capacity, they have a greater environmental impact. These use captured rainwater to flush toilets, irrigate the land, and aid other site water reduction systems.
- Rain gardens: Constructed from native plants, rain gardens add utility and value to a property. The root systems of the native plants filter runoff, keeping pollutants and toxins out of the water supply.
Point-based BMPs will vary from site to site. Still, any single practice makes a great choice in combating stormwater runoff, especially runoff contaminated by construction debris and pollution.
Linear BMPs work to protect specific areas from runoff issues. Typically, the various forms of linear BMPs involve narrow structures laid out in a straight line. Often, they sit next to streams or waterways to create filtration and erosion control.
Common linear BMPs include:
- Infiltration trenches: These create a breakwater, capturing runoff and its toxins through soil absorption. They also slow down stormwater, allowing more time for natural absorption.
- Filter strips: These are long strips of grass and purposefully-planted flora. Like a rain garden, these strips absorb runoff before it reaches a protected waterway.
- Swales: Gently-sloped depressions in the ground, swales are often covered in grass to help with absorption and filtering. The sloped sides guide runoff to proper treatment paths, such as drains.
At a house construction site, linear BMPs offer few advantages. Building infiltration trenches too close to the home’s foundation leads to water in basements. Rain gardens do the same job as filter strips, but with a smaller footprint.
Consider trenches and filter strips if the site will feature heavy construction and is located next to a waterway. Otherwise, use more targeted solutions to maximize cost, time, and space.
Area best management practices focus on turning the site itself into protection against runoff. Instead of focusing on capturing or filtering water at specific locations, area BMPs become the location.
With house construction, area BMPs often come with the design of the house. Green roofs are a common decision in green construction. Instead of a standard roof, green roofs feature a soil layer supporting vegetation. Green roofs eliminate the need for downspouts, as the layer of vegetation absorbs all water.
Porous pavement is the other major area BMP. It avoids creating an impervious surface by allowing drainage. House construction has access to several permeable pavement options, including:
- Pervious asphalt and concrete: Designed to absorb water and filter it through substrates beneath the paved surface.
- Interlocking pavers: Made of concrete or other masonry, these pavers include spaces between sections that allow water to absorb into the ground below.
- Plastic grid pavers: These are hollow honeycombs of material filled or covered with substrate, grass, or other pervious material.
Working with the homeowner, highlight the benefits of area BMPs. Not only do they protect the site itself from erosion and landscaping issues, but area BMPs also turn the site into an environmental guardian.
Unlike other best management practices, non-structural BMPs don’t focus on the site. Instead, these go beyond the site to target local and regional factors contributing to stormwater runoff.
When building a house or similar project, there are plenty of non-structural BMPs that a firm can follow. For instance:
- Protect sensitive areas: Take all necessary steps to guard any protected or conservation areas near the construction site. Often, this requires stringent wastewater monitoring and control.
- Keep site disturbance to a minimum: Construction is invasive; it requires excavation, demolition, and a lot of heavy machinery. Still, all construction firms must understand control. You must keep the existing vegetation intact in order to keep natural absorption intact.
- Educate the community: Turn the site into a source of local education. Highlight the stormwater prevention policies used at the site. Offer facts and extra contact information for additional questions. Become stewards of the environment in the new era of green-focused construction.
A significant goal of non-structural BMPs is to reduce stormwater in the first place. Educating the public and keeping natural features in place are immediate steps that any site can take.
Preventing and stopping stormwater is the responsibility of everyone. However, construction sites have perhaps the most major impact, primarily when they focus on protecting the environment.
Each site and project is different. Because of this, each site will require evaluations to determine which BMP provides the greatest effect. All of these are suggestions to be suited to fit the specific location. Combine multiple best practices to meet the needs of the area or client. Remember, the ultimate goal is preventing pollution and erosion.
Taken together, these best management practices provide a strong foundation for green, Earth-conscious construction.