Stormwater Management

You need a state NPDES Stormwater Construction permit if you are the owner or operator for any construction activity disturbing:

• One acre or more of soil.
• Less than one acre of soil if that activity is part of a “larger common plan of development or sale” that is greater than one acre.
• Less than one acre of soil, but the MPCA determines that the activity poses a risk to water resources.

Most construction activities are covered by the general NPDES Stormwater permit for construction activity, but some construction sites need individual permit coverage. Owners and operators are both responsible for submitting the permit application.

When applying for a City of Hutchinson building permit the following form must be completed and, if required, the appropriate State NPDES permit and Stormwater Pollution Prevention Plan (SWPPP) must be on file with the city.

Common Stormwater violations include:

• Lack of a site entrance to reduce vehicle tracking
• Improper installation of Best Management Practices (BMPs)
• Improper maintenance of BMP’s – not immediately cleaning up sediment lost from the site
• Not establishing vegetation on areas not being actively worked
• Inspections not properly documented or performed frequently enough

Minnesota Pollution Control Agency Stormwater Program Info

Links at the above site include the following:

• MPCA Permit Application Resources
• Online Permit Application
• MPCA Subdivision Registration Resources
• MPCA Permit Transfer/Modification Form
• MPCA Notice of Termination Application
• BMP Design Specifications and Uses
• Many other resources, references and links

Soil sediment is the single greatest source of pollution in the lakes, rivers and wetlands of Minnesota.

Across the country, approximately 1 billion metric tons of soil is lost each year in non-agricultural settings. A lot of this can be associated with erosion from all types of construction sites, including roads. Construction sites have the potential to contribute to soil erosion at a rate of up to 2,000 times that of erosion from other land uses.

The City of Hutchinson has set up a program, in conjunction with the requirements of the NPDES Program, to help address these issues. This program focuses on education and enforcement of erosion and sediment control measures:

• Controlling the velocity and volume of runoff across project sites
• Minimizing the amount of erosion that occurs
• Managing the sediments that are inevitable

The materials needed are easy to find and relatively inexpensive – sod strips or silt fence, rock entrances, quick growing grass seed. Putting these materials to use is a straight forward process. Only a few controls are needed on most sites.

Erosion Control measures for all sites should include at a minimum:

• Preserve existing trees and grass where ever possible to prevent erosion.
• Re-vegetating bare soil on the site as soon as possible with sod or appropriate seed mix. Vegetation is the most effective way to prevent erosion.
• Two rows of sod or properly installed silt fence can help protect the storm drains and trap sediment on the down slope sites of the lot
• Placing soil piles away from any roads or waterways.
• Install a 1 ¼” rock by 4” deep by 25’ access drive to be used by all vehicles to prevent tracking mud onto the road. There are alternate approved entrances as well.
• Clean up sediment that does get carried off-site by vehicles or storms immediately.
• Dispose of concrete wash water in a designated area away from areas that can reach storm drains or other waters of the state.
• Downspout extenders to prevent erosion from roof runoff.
• Properly dispose of waste – it is illegal to dispose down the storm sewer.
• Follow all required erosion and sediment control measures on construction sites.
• Inspect the site after each ½ “ or more rainfalls and perform repairs with 24 hours of discovery.
• Site dewatering may not be discharged in a manner that causes erosion, sedimentation, or flooding on the site, on downstream properties, in the receiving channels, or in any wetland.
• Proper maintenance of all BMP’s is as important as having them installed correctly.

For information on appropriate measures for your site, contact the City of Hutchinson Project/Environmental/Regulatory Manager at (320) 234-5682.

These discharges exist in many forms but all have a negative effect on the environment. Prohibited discharge detection and elimination presents many obstacles that can be resolved. Through cooperation of the city staff with residents and businesses, detection of prohibited discharges is a very effective way of reducing water pollution. A prohibited discharge is a non-storm water discharge into the storm water system or a natural water, including but not limited to:

Prohibited discharges are a major threat to water quality everywhere.

• Debris or other materials such as grass clippings, vegetative materials, tree branches, earth fill, rocks, concrete chunks, metal, other demolition or construction materials, or structures.
• The disposal or misuse of chemicals or any other materials that would degrade the quality of waters within the system, including, but not limited to chemicals (fertilizers, herbicides, pesticides, etc.) or petroleum based products (gasoline, oil, fuels, solvents, paints, etc.).
• Erosion and sediment originating from a property and deposited onto City streets, private properties or into the storm water conveyance system.
• Failure to remove sediments transported or tracked onto City streets by vehicles or construction traffic within 24 hours of it being deposited on the street.

If you suspect or witness a prohibited discharge occurring, be responsible and report it to the City of Hutchinson Project/Environmental/Regulatory Manager at (320) 234-5682.

Ponding is utilized throughout the City. These ponds are constructed to meet a variety of requirements related to the control of the quantity and quality of stormwater.

• Ponds that are either dry or wet may be constructed to provide a location for stormwater to go during larger rainfall events. These ponds are generally designed to hold up to “100-year” events. These events have a 1% potential for occurring each year. A typical “dry” pond is the one located at Elks Park in south-east Hutchinson. However, these ponds provide virtually no quality control. It is much more typical to find “wet” ponds in new construction areas such as Rolling Meadows, Island View Heights or Summerset Additions, or at HTI, Wal-Mart, Target, Menards or the Middle School.
• Quality ponds usually have a pool of water deep enough to slow down water flow and allow sediment to settle. Quality ponds may include the “wet” ponds noted above, as well as specially constructed dry ponds. Sometimes the ‘quantity” ponding can be if a parking lot or handled separately and the “quality” pond may be fairly small (i.e. Word of Life Church, Burger King).
• Some properties with limited space utilize specialized buried structures to provide quality control. Both El Loro Mexican Restaurant and the Century Cinema utilize these structures. The City of Hutchinson also has constructed structures to serve roadways.

The City of Hutchinson initiated a “Storm Water Utility” fee in 2001 to help support surface water management efforts. Many hearings and meetings were held prior to its adoption. The following Q&A link covers questions that have arisen.