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Water is an essential element for sustaining life. Rivers, streams, and lakes are the "lifeblood" of our environment. When our waterways are polluted, we know the system is in need of repair. When waterways are healthy, we know the environment can support a diversity of plant and animal species. Adequate water supply and the biological diversity that the watersheds' waters support is the key to socially healthy and ecologically balanced futures. If water is the "lifeblood" of the environment, the land that surrounds that water is the "muscles and bones" of the environment. Together, land and water make a watershed, a whole system. A "watershed" is the term describing an area of land united by the flow of water, nutrients, pollutants, and sediments, moving downslope to the lowest point, through a network of drainage pathways that may be underground or on the surface.

Generally, these pathways converge into a stream or river system that becomes progressively larger as the water moves downstream. Watersheds can be large or small. Every stream, tributary, or river has an associated watershed, and small watersheds aggregate together to become larger watersheds. Watershed boundaries are delineated using topographical maps showing the stream channel network. The watershed boundaries will follow the major ridgeline around the channels and meet at the bottom where the water flows out of the watershed commonly referred to as the watershed mouth.

Why should you care about your watershed? We all live in a watershed and everything we do on our property can have a negative impact. The land drains into tributaries and these streams or creeks flow into bigger rivers. As this water flows downhill it moves over the soil. Along the way, the water picks up many different particles of debris (leaves or soil particles), sediments that can have negative impacts on the water quality. Water can pick up as it flows: motor oil, fertilizers, pesticides, and eroded soil. Driving a car that's leaking oil or antifreeze, fertilizing your pasture or lawn, or not picking up after your pet can pollute the watershed you live in. Remember that each of you can make a positive or negative difference on your watershed.

How Healthy is Your Stream? There are thousands of small acreage farms that cover thousands of acres across the U.S. Singly, one farm may cause little pollution. But added together, small acreage can significantly impact a watershed. A stream reflects your management of the land and water. Proper upland and in-stream measures can result in clean water for fish, drinking, and swimming. You can check the health of your stream by using your eyes and legs. Here's a couple of solid indicators...

  • Water color: Clearwater is often found during low flows. Muddy color occurs during high flows and when upstream activities send sediment downstream. Tea-colored water often comes from the brown tannin of decaying leaves. A colored sheen may indicate an oil spill.
  • Foam: Froth on a stream can be natural or human-caused. Natural foam has an earthy or fishy smell. Soap or detergent foam will have a perfume smell. Stream sediment -- If gravel and cobbles are present, less than 25 percent of the gravel, cobble, and boulder spaces should be filled with sediment. A marginal to poor condition exists if more than 50 percent of the spaces are filled.
  • Algae color: Algae thrives on nutrients from commercial fertilizers, leaf waste, and manure. Light or dark green algae scattered in spots indicates a healthy stream. Matted or hairy algae mean poor stream quality. Brown algae point to sediment deposits. An algae bloom indicates excess nutrients.
  • Stream bank erosion: Bare spots on steam- banks may indicate an unhealthy stream. Wooded stream banks seldom erode, even in high floods. Steep banks, frequent tree fall, and more than 10 percent bank erosion along a stretch of the stream may indicate erosion problems.
  • Riffles: Riffles occur when water runs over rocky or rough streambeds. A mix of riffles and quiet pools provide good fish habitat. The ideal habitat for many aquatic animals is a streambed with cobbles of 2 to 10 inches in diameter.
  • Fish shelter: Submerged logs and dead trees provide good fish habitat. Stream shade -- Trees overhanging more than 50 percent of the stream bank provide good fish habitat. Less than 50 percent indicates fair to poor habitat.
  • Stream temperature: This changes across the seasons, but is generally a contributor to overall growth conditions. Check with your local environmental office for regional averages and more info.

The connectivity of the stream system is the primary reason why aquatic resources need to be managed at the watershed level. Connectivity refers to the physical connection between hill slopes and stream channels, between surface water and groundwater, and between wetlands and these water sources. Because the water moves downstream in a watershed, any activity that affects the water quality, quantity, or rate of movement at one location can change the characteristics of the watershed at locations downstream.

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Watersheds also link human dwellers in intricate social-ecological relationships. Both factors - the biophysical attributes and the policy and institutional environments - shape people's livelihoods and interactions within the watershed. A watershed is healthy when it is capable of maintaining its self-organizing complexity and diversity through time. Managing healthy watersheds requires active participation of resource users and other interested groups to collaborate in generating information to guide management planning and action. A watershed has three primary functions. First, it captures water from the atmosphere. Ideally, all moisture received from the atmosphere, whether in liquid or solid form, has the maximum opportunity to enter the ground where it falls. The water infiltrates the soil and percolates downward. Several factors affect the infiltration rate, including soil type, topography, climate, and vegetative cover. Percolation is also aided by the activity of burrowing animals, insects, and earthworms. Second, a watershed stores rainwater once it filters through the soil.

Once the watershed's soils are saturated, water will either percolate deeper or run off the surface. This can result in freshwater aquifers and springs. The type and amount of vegetation, and the plant community structure, can greatly affect the storage capacity in any one watershed. The root mass associated with healthy vegetative cover keeps soil more permeable and allows the moisture to percolate deep into the soil for storage. Vegetation in the riparian zone affects both the quantity and quality of water moving through the soil. Finally, water moves through the soil to seeps and springs, and is ultimately released into streams, rivers, and the ocean. Slow-release rates are preferable to rapid release rates, which result in short and severe peaks in streamflow. Storm events, which generate large amounts of run-off, can lead to flooding, soil erosion, and siltation of streams.

Ultimately, the moisture will return to the atmosphere by way of evaporation. The hydrologic cycle (the capture, storage, release, and eventual evaporation of water) forms the basis of the watershed function. A watershed should be managed as a single unit. Each small piece of the landscape has an important role in the overall health of the watershed. Paying attention primarily to the riparian zone, an area critical to a watershed's release function, will not make up for the lack of attention to the watershed's uplands. They play an equally important role in the watershed, the capture, and storage of moisture. It is seamless management of the entire watershed, and an understanding of the hydrologic process, that ensures watershed health.

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