What is a watershed?
A watershed is essentially a catch basin that is defined by high points and ridgelines. These higher elevations descend into stream valleys. Precipitation and runoff make their way from the upper reaches of the basin to the ocean though soil, groundwater, streams, and rivers. Whatever happens upstream (e.g. erosion, pollutant discharge, septic effluence), eventually makes its way downstream.
why protect watersheds?
Climate. Our local climatic patterns are influenced by multiple factors. The more widely known factors include our geographical location on Earth, our distance from the sun, upwelling from the California current, and other physical influences. How these physical forces impact ecosystems is not yet wholly understood.
Physical and ecological factors interact in a feedback loop. Healthy ecosystems promote a positive feedback loop, creating climatic patterns favorable to our native fishes, birds, plants, and countless other organisms. Modified ecosystems, such as those with areas developed by humans, have an altered ability to sustain the positive feedback loop, as the climate shifts to one that is less favorable to native plants and animals.
It is essential to protect our watersheds in order to maintain healthy ecosystems that will continue to foster climates favorable to native plants and animals. This goes for both the larger regional climate, as well as micro-climates that various plants and animals within our watersheds require. For example, on the watershed-scale, forests can transport moisture from the ocean far inland. On a much smaller scale, trees shading streams keep water temperature low, which helps sustain native salmon species.
Habitat. With all the human activities in our watersheds today, habitats favored by our native plants and animals are increasingly compromised. Pollution of air, water, and soils, habitat fragmentation, and the introduction of invasive species are all pressures acting to strain the ecological integrity of our native ecosystems.
Watershed-oriented conservation can systematically and more efficiently address multiple ecological pressures on our native habitats. Take for example the revegetation work SDCWC has conducted in the riparian zone of the Salmon River.
This work has improved habitat both within and beyond affected stream reaches, by lowering water temperature to a level preferred by salmonids, stabilizing stream banks, reducing sedimentation of downstream reaches, providing nesting sites and forage for wildlife, and creating a vegetation buffer that filters overland pollutants.
SDCWC's restoration work in the Salmon River estuary has yielded a number of positive outcomes for the watershed by increasing the area of wetland habitat for wetland species, which aids in the filtration of upstream pollutants, improving the capacity of the estuary as a nursery for juvenile salmon, and reconnecting the wetland the surrounding ecosystem, which mitigates habitat fragmentation.
watershed links for learning
Here are some links you may find useful in learning about your local watersheds, including how to be a better steward of this landscape.
OSU Rain Garden Guide - PDF how-to manual
EPA Watershed Academy - training series
Lincoln County Rural Living Handbook - PDF manual
USGS Water Resources Data - local current streamflows
NOAA flood predictions for northwest rivers
OSU Sea Grant - coastal science, education and news
Resilience and quality of life. The health of our watersheds has a direct impact on our quality of life. Healthy watersheds provide access to clean drinking water and salmon can thrive in our streams. Our communities can enjoy recreational activities, grow economically and become more resilient to climate change.
In a changing climate, the ability of an ecosystem to bounce back from disturbances and retain its ecological functions is critical to all of its inhabitants – humans, plants, and animals. Without resilience, all of us will have to adjust to a new ecological reality, if we can.
A healthy watershed is more resilient to the pervasive effects of climate change than a watershed that is stressed by various pressures, such as pollution and habitat fragmentation. A protected watershed can also increase the resilience of human communities to natural disturbances such as storms and floods.
The health of a watershed affects the quality of our drinking water. A sufficiently protected watershed has the capacity to supply water to its inhabitants in the long term by capturing and storing precipitation.
A healthy watershed also has the capacity to filter water and remove contaminants from various land uses within the watershed. This filtration capacity provides us with naturally clean drinking water and can reduce the economic cost of operating a water treatment plant.
For more information on the hydrological services of a healthy watershed, see Postel and Thompson (2005) Natural Resources Forum 29, 98–108.
WATERSHED EDUCATION COURSE