Even if you’ve been living under a rock, you have experienced the Water Cycle in action. Rain falling from the sky, water seeping into the ground, a flowing river, plant roos sucking up moisture; each is an example of water moving from one ecosystem to another. Protecting the Water Cycle is vital to keeping humans, animals, and the environment healthy. In the figure, you can see the planet-wide transformations that drive the cycle. Salt water in the ocean evaporates into the atmosphere and forms clouds. Clouds deposit rain and snow on the landscape. Water flows along the surface or underneath the ground. Plants and animals, including humans, use this water to survive, then release some of it back into the environment.
At any point, water may pick up pollutants that hitch a ride into future stages of the cycle. Litter, sediment, and invisible contaminants (like fertilizers, oils, pesticides, and other chemicals) get carried across land and downstream to water bodies during a heavy rain or snowmelt. Exhaust from industrial processes can travel through the air to clouds and create acid rain. A combination of many different sources of pollution adds up throughout a watershed and can harm the living things it contacts. On Fort Wainwright, water travels across the land into the Municipal Separate Storm Sewer System, which feeds into wetlands and the Chena River. Each leaking vehicle, sewer backup, or pile of dog poo, has the power to impact our valuable water.
A functioning ecosystem can filter out some pollution, but it can only do so much. Permeable soils, vegetation, and wetlands are a few examples of natural filtration zones which absorb water and contaminants to create a “sink” to slow the water down. These natural filters are often bypassed by human-created surfaces like parking lots, roofs, or culverts. While drainage systems may prevent flooding in an urban area, they also force all of that runoff to skip filtration and invade a wetland or waterway. Using strategies called “Green Infrastructure,” we can use designs that act like natural filtration zones and protect the Water Cycle. Examples of Green Infrastructure on Fort Wainwright include the trees and shrubs planted in front of Hangar 3 and the grass swales (gently-sloped ditches) that wind through housing areas like Tanana Trails.
Already, the planet has a limited water supply, mainly in forms unusable to humans such as salt water in the oceans, the polar ice caps, permafrost, or freshwater polluted with un-drinkable chemicals. In the United States, past pollution has made 40 percent of the nation’s rivers and lakes unsafe to swim in or fish from. That’s why we all need to do our part in preventing pollution. Every little thing we do to protect water quality can make a difference in the Water Cycle!
By: Ida Petersen and Bill Favitta
U.S. Army Garrison Alaska Department of Public Works Environmental Division Water Program