There’s an old adage that a good contractor is also a good neighbor: considerate of others and careful to leave no dirty tracks behind. That credo extends to neighboring waterways as well, thanks to the efforts of the Minnesota Pollution Control Agency (MPCA).
The MPCA oversees construction activities throughout the state to protect our valuable water resources. When stormwater drains off a construction site, it carries sediment and other pollutants that harm lakes, streams and wetlands.
Construction site owners and operators are required to create and maintain a Stormwater Pollution Prevention Plan, or SWPPP, to control stormwater on their jobsite. Compliance is monitored by inspectors and owners and contractors are subject to significant fines for failure to adhere to stormwater management controls.
A SWPPP is required for any construction activity that will disturb more than one acre of soil. It is also required if the project is under an acre in size, but part of a larger common plan of development; or if the MPCA determines that the activity poses a risk to water resources. Kraus-Anderson follows Best Management Practices (BMP’s) for stormwater management on every project, regardless of size, according to Kraus-Anderson General Superintendent Dan Braaten. All KA superintendents receive SWPPP certification training and continuing education through Kraus-Anderson University (KAU) to keep current with requirements and BMP’s. KA also maintains a SWPPP resource team available for additional support and guidance on storm water management issues.
The two main components of storm water compliance are resource protection, and documentation.
Documentation requirements include reporting of the site and its SWPPP installations, inspections every week and within 24 hours of any rainfall of a half inch or more, and corrective action when and if installations are not performing correctly. Communication to all subcontractors and suppliers is also important to make sure the program is enforced.
Resource protection specifics vary greatly from one site to another depending on factors like grading, soil conditions and proximity to impaired or unimpaired waters. But basically, “Everything is set up as a big filter to protect the waters of the state,” said Kraus-Anderson vice president and project manager Jim Beckwith.
Additional rules apply for construction projects that add an acre of impervious surface, i.e. pavement, rooftops, or any other surface that prevents drainage. Even gutters are considered tributaries to ‘protected waters,’ as they don’t allow filtration, said Beckwith.
A variety of SWPPP implementation tools may be seen on any given job site. Some of the more common are:
Silt fences- These are anchored mesh fences that are set up in a down gradient to allow water to run through while “catching” silt. Built up silt is periodically removed from the fence.
Berms- A built-up earthen barrier or even a curb pavement can prevent water runoff.
Catch basin filters- mesh baskets or other filters may be added to existing storm drains or other areas where water collects. These must be monitored and cleaned out regularly.
Washdown area- a designated area on a job site for trucks, concrete mixers or other dusty equipment to be washed down prior to leaving a site. The wash water is collected and removed in an MPCA- approved manner from the site.
Rock entrances- crushed rock at jobsite entrances can pull muck from tires and help prevent track out.
Temporary sediment ponds- artificial ponds can be created to direct runoff and are later cleaned out.
Pavers and net lawn systems- these are attempts at creating pervious surfaces on developed sites to encourage stormwater filtration.
Hydroseed- To prevent wind or water erosion, exposed soil must be mulched or hydroseeded if left exposed or unworked for seven days. Hydroseed is a planting process that uses a green slurry of seed, mulch and fertilizer sprayed over exposed soil. Hydroseed has an adhesive quality that coats the soil and helps tack it into place. Many a jobsite will “button up” for the winter by blowing a green blanket of hydroseed over exposed soil before the snow flies.
Hydroseed is also used to revegetate disturbed landscape at the end of a project. The MPCA requires the construction permit holder to replant, and at least 70% of the seeded area must take hold for erosion prevention.
Even with the best intentions of working with nature, sometimes nature wins. Beckwith recalls the replanting process during the Trails of Orono project, a beautiful senior living facility tucked neatly into a serene woodland and wetland area.
“We seeded the soils around the entrance and they would not take hold,” Beckwith recalls. “We seeded that area three times, and we could not figure out why it would not grow.”
“Then, one day, we saw 18 wild turkeys show up for breakfast. We were feeding the turkeys!”
Which brings to mind another old adage: Good fences make good neighbors.