Construction and Long Term Storm water Management - Photo Essay

This photo essay was designed to show some methods used to control erosion before, during and after construction and to review some long term storm water management methods installed prior to your business operations. Once you have completed reviewing this page, hit your browser's "back" button to return to the storm water small business pages.

NOTE: Two Technical Guidance Documents that will help

Before reading the following photo essay, note that The Wisconsin Department of Natural Resources and University of Wisconsin Extension have each published a technical guidance document to assist you in creating your plan.

Construction Storm water Management (Erosion Control)

When beginning to locate your small business on a new property, it is important to design your site with erosion control and construction storm water management practices in mind. Minimizing Protecting islands of vegetation can greatly increase the stormwater-absorbing ability of your new business site and can enhance its aesthetic appeal. land disturbance and keeping native vegetation and soils in place will have the greatest long term impact on protecting the watershed and any nearby water bodies (lakes, rivers and wetland areas) where runoff ultimately travels to. This up-front planning will save dollars otherwise earmarked for storm sewer fees, lawn creation and maintenance costs, and disposal charges, to name a few.

An excellent resource published by UW Extension is Preserving Trees During Construction - pdf (EXIT DNR) (222 K).

But some land disturbance will ultimately occur due to building footprint needs, parking areas, driveways, etc. Since a construction and long term storm water management plan is required prior to any construction activities, please read through the following key points to assist you in creating and implementing sound erosion control and flow management plans for your small business site.

Site Phasing

When first creating your erosion control plan, try to design site phasing into the construction. Site phasing minimizes soil erosion by having smaller portions of your site disturbed at any one time (e.g. fitting the development to the topographic "lay of the land", minimizing the development footprint by clearing only the land required for buildings, roads, and utilities, and providing buffers from natural drainage systems and water bodies).

For more information on site phasing, please refer to the following article: "Practical Tips for Construction Site Phasing (EXIT DNR)"- (PDF, (680 KB) Published by the Center for Watershed Protection

Sediment Controls

Sediment control practices are designed to remove some of the soil particles that are suspended in runoff. By using properly installed silt fencing, straw bales, sediment traps or sediment basins, any sediment or other materials will be held in place on the construction site and not end up in wetlands, lakes, or rivers. These should be written into the erosion control plan and installed within 24 hours of any land disturbance.

Silt fencing, if installed improperly, can cause a greater release during a major rainfall event.

An example of a properly installed silt fence

Photos used with permission from the Center for Watershed Protection.

A good source of information on proper instrallation of straw bales and silt fences is the UW Extension publication "Erosion Control for Home Builders" - pdf (EXIT DNR). This document covers the more common erosion control practices used during development of a site.

Erosion Controls

Turf Reinforcement Matting Mulches, blankets and matting, seeding and soil stabilizers are used to stabilize a recently disturbed area and minimize the dislodging of soil particles by raindrop impacts and flowing water. Someadvantages include: reducing flow velocities of storm water through the area and reducing moisture loss when seeding and planting is done. They prevent crusting and sealing of the soil surface and moderate soil temperatures. This allows seed germination to occur more readily. And they increase infiltration of storm water at the site.

Mulching: A protective blanket of straw or other plant residue, gravel, or synthetic material applied to the soil surface to minimize raindrop impact energy and runoff, foster vegetative growth, reduce evaporation, insulate the soil, and suppress weed growth. Mulch provides immediate protection, and straw mulch is also typically used as a matrix for spreading plant seed. Organic mulches such as straw, wood chips, and shredded bark have been found to be the most effective. Straw typically requires some kind of tacking, such as liquid emulsions or netting. Netting may also be needed to hold mulch in place on slopes.

Protective blankets hold soil in place and help establish ground cover. Mats and blankets are made from a wide variety of organic and synthetic materials and are useful in establishing grass in swales and waterways, plus they promote seedling growth.

Erosion Control Products Availability List

Erosion Control Product Availability Lists (PAL) - Wisconsin DOT (Exit DNR)

The above list was compiled by the Wisconsin Department of Transportation to highlight advances in erosion mats, soil stabilizers, tackifiers and silt fences.

Long Term Storm water Management Plan (Flow Management)

Planning for long term collection and treatment of storm water runoff early in your site planning process will save dollars and protect nearby waterways. When writing the long term storm water management portion of your plan, include the following commonly used practices. These practices, when used solely, or in combination, will hold back sediment while allowing runoff water to seep slowly back into the ground.

Wet Detention Basins

A permanent pool of water with designed dimensions, inlets, outlets and storage capacity, constructed to collect, detain, treat and release stormwater runoff. The wet detention basin is the most common long-term stormwater management practice used in Wisconsin.

Infiltation Basins and Trenches

Infiltration basins and trenches are used to hold sediment in place, preventing it from choking out and making wetlands ineffective or adding to silty deposits in nearby rivers and lakes. These basins can be very important during larger storms when other storm water management practices cannot treat or recharge runoff as well.

Grassed Swales

Grass swales or filter strips clean the stormwater while allowing it to absorb into the ground. Grassed swales function by slowing runoff as it comes off an impervious surface (such as the principal parking area for your business). The grassed swale can remove sediments and other pollutants and provides some infiltration into the soil. A drawback, however, is that they can be ineffective at treating and absorbing runoff during a larger rain event.

Storm water Wetlands (a.k.a constructed wetlands, artificial wetlands)

Stormwater ponds can be visually appealing, provide cover for amphibians, birds, and small mammals, and educate children on the importance of watershed protection. Storm water wetlands are shallow pools that have wetland plants which remove pollutants through biological uptake. They are among the most beneficial in removing pollutants and are aesthetically pleasing, as well. Storm water wetlands can provide educational and habitat benefits and can be incorporated into any existing ponds or swales you may already have in place.

Parking Lots - Pavers, Porous Concrete and Bioretention Islands

Parking lot using pavers instead of blacktop Can your small business design a better parking lot? According to Watershed Protection Techniques [3(2): 647] "parking lots rank among the most harmful land uses in any watershed. They not only collect pollutants that are deposited from the atmosphere, but also accumulate pollutants that leak, drip or wear off cars."

The article also mentions several design ideas such as reducing stall sizes, narrowing drive aisles and using inovative materials and practices such as grid pavers, porous concrete and bioretention islands (photos below) to absorb storm water.

For more information on better site design oprtions, please refer to the following article: "The Benefits of Better Site Design in Commercial Development"- (PDF, 680 KB) (EXIT DNR) Published by the Center for Watershed Protection

Concrete lattice closeup Concrete lattice installed in gas station parking lot

Lattice closeup There are several inovative ways to allow stormwater to absorb into the ground such as pavers (interlocking blocks) and.porous concrete.

Bioretention islands can be built into your parking lot design to catch and absorb stormwater. The island can be planted with a variety of native plants to beautify your parking facilities, as well.

The above two photos used with permission from the Center for Watershed Protection.

There are several other long term flow management practices that can be incorporated into your site design to minimize your impact to the local watershed and save you money. Please refer to the "Related Links" (button found along the left margin of most pages within the Small Business Web Site) topic when you have completed the other topics.

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