Low Impact Design & Green Infrastructure
To make a neighborhood, business park, or other development compatible with the natural function of the landscape, environmentally sensitive design concepts should be used. Environmentally Sensitive Design helps to balance community needs, budgetary limitations, and natural ecosystem functions. Importantly for the health, safety, and beauty of water resources both on and near the development, environmentally sensitive design often directs stormwater to a place where it can be held and treated onsite before being released to nearby bodies of water.
Environmentally sensitive design might include Green Infrastructure practices. Much like stormwater best management practices, green infrastructure helps to mitigate issues related to stormwater runoff. However, whereas some stormwater BMPs are structures that don’t provide additional benefits to the watershed such as aesthetic improvements, recreational space, or natural habitat, green infrastructure is engineered to mimic natural systems that provide more benefits than simply redirecting water.
Low Impact Development is fairly synonymous with green infrastructure, often looking at incorporating nature-based solutions to stormwater problems on the scale of a development or re-development.
Municipalities may have ordinances that affect your environmentally sensitive design. Make sure you have researched what is allowed in your community when tackling a design project.
There are many examples of successful environmentally sensitive design in southeastern Wisconsin! Check some out below!
Types of Green Infrastructure
There are many types of green infrastructure. Here are examples of a few. Use of multiple green infrastructure installations can help create a stormwater management system that is resilient and mimics natural processes.
Rainwater Harvesting Structures
There are many different types of rainwater harvesting structures that can meet a diverse set of needs. Rain barrels are often used for smaller private properties. As the size of the roof increases, above or below-ground cisterns can be used to catch more water. Other devices exist to capture and store rain water as well; any of these devices can be used to save water to use on gardens and lawns later during dry weather.
Rain Gardens
Rain gardens are gardens that are designed to capture rainwater and divert it from becoming runoff. This is done by placing it in a location where water will run towards it, modifying the soil so that water can filter into the ground, planting plants that can tolerate moisture and also help water soak into the ground, and by maintaining it so that it continues to work over time. For more information on rain gardens, visit our page Add a Rain Garden.
Bioswales
Bioswales look a bit like large, deep rain gardens, but they also function as channels to move water away from infrastructure while also allowing for infiltration. They are generally built on larger private or public properties, or on right-of-ways. They may have native plants or grasses planted within them, depending on the need of the landscape.
Pervious / Permeable Pavements
Pervious or permeable pavements and pavers reduce the amount of runoff that comes off of a parking lot, road, or other paved area. The gaps between pavers or within the aggregate of the pavement allow water to filter through the paved area and into the soil beneath. For more information on this type of green infrastructure, visit our page Permeable Pavement.
Blue / Green Roofs
Green roofs, or blue/green roofs, capture and store water that falls on the roofs of buildings. Green roofs use that water for plants that are planted directly on the roof, or in trays that are placed in grids on the roof. Blue/green roofs do this and also store extra water in a cistern or other device for later use.
The green roof above, at the UWM School of Freshwater Sciences, has trays with plants.
Urban Tree Canopy
Trees are green infrastructure too! Their leaves catch water before it hits the ground, allowing some to evaporate and some to run down into the earth more slowly. Their roots help absorb water and direct some of it down into the soil. The roots also hold soil in place so it isn’t washed away. For more information about how trees prevent stormwater pollution, visit our page Hardworking Trees.
More Resources
In addition to the resources mentioned above, there are other places where you can learn about different types of green infrastructure, low impact development strategies, and other environmentally sensitive design practices that may be appropriate for your site. Taking advantage of these resources is especially important for developments and re-developments that may be affected by the Milwaukee Metropolitan Sewerage District’s Chapter 13 Rule.
The MMSD has a Fresh Coast Resource Center website that provides information on many types of GI strategies; visit www.freshcoastguardians.com/resources/green-strategies to check them out. The District has also released a publication to help site owners or contractors develop a GI Plan, required in some situations. Find the guide here.
Developers interested in becoming Wisconsin Green Built Home certified can find more information about this program, and strategies for using Low Impact Development principles toward credit for this certification, on WEI’s website.