Low Impact Development

Jeffrey A. Gordon, M.D.

In my August 27th article (Water, Water, Everywhere…), I talked about what happens to water from its sources, through its use by all of us in our daily lives, and to its return to the land. Land use activities have varying degrees of impacts upon the land itself and thus upon water. This occurs not only when land is prepared for use or a building is constructed, but as the land or a building is used or re-used over time.

There is no land use activity that has a zero impact upon the land. Not all land use impacts are bad. We need places to live and to raise our families. We need places to work and to shop. We need schools, municipal infrastructure, streets, parking lots, parks and fields, farms, and so forth. They all require someplace in our towns to be built. Our communities depend upon all of these things. What happens in one part of your town can affect another part. What happens in one of our towns can affect the entire Quiet Corner. What happens at one point in time can affect what happens at a later point in time. Things do not happen in isolation. Planning and zoning commissions spend a lot of time thinking about these issues when it comes to dealing with stormwater runoff. Sounds boring? In fact, it is an important aspect of land use and development because not only is water a much needed and valuable natural resource, but water runoff if not handled properly can cause flooding and soil damage, pollution, financial costs to manage, and loss of water recovery needed to recharge our water sources.

One way to approach this challenge is through the use of low impact development (LID). According to the Environmental Protection Agency (EPA), it is “an approach to land development (or re-development) that works with nature to manage stormwater as close to its source as possible”. Current stormwater best management practices rely upon man-made structures to deal with stormwater runoff and soil erosion after the stormwater develops. We are familiar with seeing catch and retention basins, drainage pipes, ditches, street curbs, and sewers. Usually hidden from our view are the water pollution abatement facilities to clean the stormwater before returning it to our water source systems. What LID does is to use the landscape, groundscape, and natural resources to effectively deal with stormwater runoff and flow, in ways that mimic the natural processes all around us. This is to minimize erosion, flooding, and pollution; to maximize the return of water to watersheds and ecosystems; and to maintain good water quality. The landscape itself is used as the proactive, functional means to accomplish this effort at the source where rain falls to the ground. It is an integrative management system that can be used as an alternative or complement to conventional stormwater best management practices.

LID can have an advantage over conventional stormwater management in that unlike rigid man-made structures, it can be adapted to meet the specific characteristics of a neighborhood, urban center, individual house lot, different parts of a piece of land, or other land use scenarios. It can be used in small and large scales. When needed, it can be combined with standard stormwater best management practices.

Some of the practical applications of LID include:
  • An inventory assessment of co-occurring natural resources, including existing land use (zoning) activities and growth build out maps for communities;
  • Design and construction plans on small and large scales so as to best fit specific land uses/developments onto individual plots of land and into surrounding regions, respectively;
  • Minimization of the disturbances to the landscape, removal of existing buffers and wetlands, and changes to the soil so as to preserve as much as possible nature’s methods to direct, buffer, clean, and buffer stormwater;
  • Use of appropriate trees, grasses, and plantings to replicate natural landscapes that already manage water;
  • Use of porous or permeable paving materials so as to decrease the amount and speed of stormwater runoff and to lessen the time water contacts pollutants;
  • Lesser needs to build and maintain costly man made structures; and
Improved aesthetics by preserving natural landscape features and using plantings to soften hardscapes (such as parking lots and streets).

A number of analyses of conventional stormwater management versus LID have shown that the use of LID techniques could decrease upfront land development and long-term maintenance costs. This may not be the situation every time, but such analyses can be done by planning and zoning commissions on a case-by-case basis to determine the true potential benefits. Such benefits are not just financial, but also environmental.

A comprehensive LID resource developed by the Southeast Michigan Council of Governments can be found at www. semcog.org/lowimpactdevelopmentreference.aspx.

This is not to say that LID can be used for every land development activity every time or that all features of LID can be used all of the time. It is not the only way of doing things. It is however one way of doing things. This is where the creative, flexible, and common sense thinking of planning and zoning commissions come into play. One can look at different development options to best determine which one best fits for a particular proposed land use in a particular area and surrounding community. It is a land use planning tool used to better manage and maintain natural resources and to lessen the impact upon municipal infrastructure caused by growth and development. It is about guiding land use activities so that we balance the important individual rights of property owners and the needs of everyone in our towns.

Back to the list