Is your watershed healthy?
Poor land use practices, failing infrastructure, pollution, and climate change can cause an array of water problems. Before you come up with a plan to protect your watershed, you need to know which problems are most critical for watershed health, and what’s causing them. The more specific the information you gather, the better you can direct your efforts toward problem-solving.
The condition of a watershed depends on the health of its parts: rivers, streams, wetlands, groundwater and aquifers, and land area. If the watershed you’re concerned about is very large, you may want to break it down into sub basins for easier evaluation.
Evaluating watershed health
Watershed science describes basic characteristics that can be used to measure watershed health. For additional information about these characteristics and how to measure and evaluate them, refer to Connecting the Drops and these references. The following list is a summary of watershed health characteristics.
1. Water quality
Evaluate water quality in the watershed’s main river or stream, its tributaries and wetlands, and wells. Sometimes you can see contamination, but often pollutants like chemicals and bacteria are invisible to the naked eye. Find a reputable lab to evaluate your samples.
In some streams aquatic life indicates water condition. Biomonitoring is a field technique used to measure the degree of water degradation by sampling macroinvertebrates on the stream bottom.
2. Vegetated buffers
Adequate vegetated buffers along the edges of all rivers, streams, lakes, and wetlands in the watershed are critical for maintaining the health of these water resources. Buffers must be wide enough to protect water, slow flooding, and provide habitat.
River and stream floodplains that are in good condition can absorb significant flood flows. Construction, impervious surfaces, and vegetation removal in floodplains prevents them from providing this protection.
Vegetation improves the condition of river and stream banks and prevents erosion. Erosion adds to water pollution and affects the stream’s capacity to carry flood flows.
5. Wetlands and small streams
The presence and condition of small wetlands and streams determine how well the watershed can store, distribute, absorb, and clean water. All wetlands and streams (regardless of size or regulatory jurisdiction) can contribute to watershed health.
6. Impervious surface
The amount of impervious surface (roads, buildings, pavement) as a percent of land cover in the watershed has a direct effect on watershed health. Impervious surfaces increase flooding and water contamination.
Forested land is important for watershed health, both as a percent of land cover within the watershed and in riparian corridors along edges of streams and rivers.
Healthy watersheds have healthy aquatic and wetland ecosystems. Evaluate stream, wetland, and lake ecosystems throughout the watershed, noting their size, condition and biodiversity.
The following are additional considerations to evaluate when looking at the condition of your watershed:
How is water used?
Water use includes water needed to maintain aquatic and wetland ecosystems as well as water for human use (level of demand, drinking water, sources of water for domestic, industrial and agricultural use).
How does groundwater depletion affect streams, rivers, and wetlands?
Does a river or stream have adequate flow to maintain its health as an ecosystem? Is a wetland’s hydro
How well are flood waters stored and contained?
What are the sources of pollution in the watershed?
What are the effects of climate change on the watershed?