Earth Day Might Also be Called Water Day
by Margaret Rader, Chehalis River Council
As I write these words, rain is falling on our pastures and on the Douglas fir, the Indian plum, the oaks and maples. Maybe rain will be falling when you read this. For me, Earth Day is an opportunity to celebrate the cycle of life that binds us to the place where we live. I urge everyone to celebrate Earth Day by getting out and walking around your place. Nature is everywhere, even inside us, but for us to be good stewards we need to cultivate awareness
Rain here is so ordinary that we need to work to be aware of it. Rain is not just something that spoils the picnic. It's not just what keeps everything green. Rain shapes the place where we live. One way to think about our place is to find our watershed. A watershed is a system including a river and the streams flowing into it; a watershed is also the land through which the water flows. You will find where your watershed ends and another begins by finding the highest ridge line. On your side of the ridge, all the water eventually flows into a central river. For many of us, this central river is the Chehalis. For others, the central river is the Cowlitz or the Nisqually
These are separate watersheds, and one can notice that the Cowlitz flows into the great Columbia River, so it is a sub-watershed of the Columbia watershed.
In the Chehalis watershed or basin, all the creeks and streams flow into other creeks and streams that eventually flow into the Chehalis River, which flows into Grays Harbor and joins the ocean. Rain falls, and some runs off into the creeks or streams. But rain also soaks (the technical term is "infiltrates") into the ground. Up till recently, I confess that my mental picture of this showed this water going "straight down" and then spreading out in a sort of circle. Not so! Water that soaks into the groundwater table moves toward the central river. Hydrologists map the direction of groundwater movement. The aquifers that hold the groundwater on which our drinking water wells depend are not static pools or lakes, they are water in movement through layers of sand, gravel, or porous stone. Your watershed is the place where all the rain that falls moves toward a central corridor to the sea
What will happen to the rain that just stopped falling? Some will run off the surface into the ditches, creeks, and streams downward to the Chehalis River and Grays Harbor. Some will evaporate from the surface. Some will soak into the ground, to join the groundwater table as it moves toward the river bed
Some will be taken up and used by plants (either through the roots or the leaves) with a portion released into the air again through the leaves (called "transpiration"). Some will sink further and move along in the aquifer. Some will be used for irrigation, to fall as artificial rain and play its part again in the cycle. Some will be consumed by animals, who return a portion to the ground. Some will be used for human consumption, and humans too will contribute their share back into the cycle through septic tanks and sewage systems. There is no life without water, and there is no water without the water cycle
The cycle has no ending, for some of the rain that fell high in the hills of the watershed will make it into the great ocean, where weather patterns of heating and cooling turn evaporated water into clouds. These sweep in from the ocean to return water to the earth as rain.
When we understand this cycle, we understand how human activity affects it
Because water is liquid, it picks up many kinds of impurities. And because water flows, it moves these impurities. And because water flows toward a central low corridor to the sea, it concentrates these impurities. When soil erodes into runoff, the water is filled with sediment, it's "dirty." All kinds of pollutants that sink into the ground can move along with water through the watershed. This includes bacteria such as fecal coliform from human and animal waste and chemicals such as those found in pesticides and industrial wastes. Motor oil spilled on a gravel driveway doesn't just stay in one place. It can reach your salmon-bearing creek as runoff or it can reach the same creek after soaking in and moving through the groundwater table. Dairy manure can soak through pasture land into the water table and move slowly but surely through the aquifer, perhaps toward your well. Water is purified to some extent by moving through streams or the ground, but there is a limit to how much pollutants can enter the system without ruining habitat for fish or human beings.
Let's celebrate Earth Day by getting out and watching water on the move through our earth. When we imagine our place in the water cycle, we can imagine how to protect the purity of our water for the sake of fish and humans
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