A watershed is an area of land that drains to a common body of water. Any area of land within the watershed may contribute runoff and associated pollutants to that lake, river, stream, or wetland.

The water quality in a given lake, river, stream or wetland is directly affected by the land use in the watershed. Studies show that as intensity of land use increases, the potential for water resource degradation increases. This is because as we change the landscape, human activities (such as development, logging, or farming) disrupt the natural movement of water through the watershed. These changes result in increased runoff to surface waters, decreased infiltration to groundwater, and increased movement of pollutants into all waters.

So, watershed management is mostly about land use. If your community values an abundant supply of clean water, then it's critical that your land use planning have a watershed planning component.

What is watershed planning?

Watershed planning follows the same steps and principles as Natural Resource Based Planning, with one key difference. Because watershed lines ignore political boundaries, it's critical that all communities with land in the watershed are involved in the watershed planning process.

A watershed plan should include an inventory of water resources and identify threats to high quality waters as well as opportunities to restore degraded ones. The plan outlines a watershed management strategy for protecting and improving lakes, rivers, streams, and wetlands.

What is watershed management?

Watershed management employs a wide variety of tools to ensure lakes, rivers, streams, wetlands, and groundwater supplies are protected or restored to meet stake holder goals. Efforts to minimize impacts by land use changes like farming, logging, and development become a focus of many watershed plans. Listed below are just a few of the ways you can protect water resources.

Conservation Design and Low Impact Development (LID): Development results in the addition of impervious surfaces, which cause flooding and degradation of water quality by increasing storm water runoff and nonpoint source pollution. Conservation Design focuses on techniques to preserve existing natural areas and minimize new impervious surfaces. LID is a collection of innovative storm water management tools that encourage water to soak into the ground or be used by plants as it would under natural conditions. LID treats storm water as a valuable resource, incorporating rain gardens, green roofs, pervious alternatives to pavement, and much more into development projects. These techniques minimize storm water runoff and nonpoint source pollution, and maintain/restore the natural water flow (hydrology) of the landscape. To learn more, visit the Low Impact Development (LID) Center.

Buffers: Buffers, which are uncut zones of vegetation adjacent to water bodies, are the last line of defense against nonpoint source pollution. Plants filter pollutants out of storm water and they reduce the amount of water and the speed at which it flows into wetlands, streams, rivers, and lakes. Buffers also provide habitat diversity, stabilize shorelines, and provide visual interest. To maximize effectiveness, buffers should use native vegetation and be as wide as possible (at least 25 feet and up to 300 feet or more depending on the type and quality of the waterbody).

Conventional Stormwater Management: Conventional storm water management treats rain water as a waste product by piping it through storm sewers to our lakes and rivers. In most cities, the runoff is not treated at all. Since the 1980s, many communities require the water to be treated in ponds before it reaches receiving waters. These ponds clean the water somewhat, but do not allow much water to infiltrate into the ground. Infiltration of rain water is critical to recharge groundwater supplies, reduce flooding, and filter the water through the soil. Stormwater ponds are still an important tool for treating runoff, but other tools are needed to ensure clean water resources.

Erosion Control: Soil erodes when construction sites, logging, agriculture, and other activities disturb the land. Eroded soil, or sediment, reduces water clarity and smothers aquatic habitat. Moreover, it carries other pollutants like bacteria, nutrients, and toxic contaminants, which degrade waterbodies and make them unsafe for human use. Erosion control, which employs a wide range of practices and products, is one of the most effective watershed protection tools available.