Mark Twain is quoted as saying, “Whiskey is for drinking. Water is for fighting over.” Most of us understand the value of water, and depending on where you live, you may have a lot of water or very little. We don’t know a lot about groundwater and how long it will sustain us as we continue to install more and more wells. There is also mounting evidence that the glaciers of the Cascade Mountains, which provide some communities such as Hood River and Trout Lake their municipal and irrigation water, are shrinking. And precipitation varies widely in the Columbia River Gorge, as much as 99 inches of rain each year in some parts of Skamania County and single digits on the east end of the Gorge.
Rain and snowmelt are valuable resources — free and relatively clean — that can be conserved and used beneficially in many ways. Rainwater harvesting is often thought of as collecting the run-off from a structure or other impervious surface in order to store it for later use as drinking or irrigation water, but rain can also be collected and stored in the land to support vegetation for food, shade and beauty, reducing demand for groundwater, lowering utility bills, and improving wildlife habitat. Rainwater is better than some municipal water sources for landscape plants and gardens because it is not chlorinated.
The idea of rainwater harvesting usually conjures up images of an old farm cistern or thoughts of developing countries. The reality is that rainwater harvesting is becoming a viable alternative for supplying our households and businesses with water. It’s not just for the farm anymore! In Germany and Australia, and even on Washington’s San Juan Islands, rainwater harvesting for whole-house usage is commonplace.
Perhaps you have places on your property where rainwater collects or runs off impervious surfaces, roofs or pavement, carrying potential pollutants like pesticides, road contaminants, soil or animal waste with it into nearby streams. Whether you store rainwater in the land or in storage tanks, by harvesting rainwater you can reduce drainage problems, stormwater runoff and the resulting erosion at your home or business.
For household or irrigation use, or as a back-up to wells or municipal water, rainwater harvesting involves collecting the rain from a roof that is made from a material that will not contaminate it, such as metal, slate, tile or elastomeric paints approved for rainwater collection. Rain gutters channel the water through downspouts into storage tanks or simply into a clean barrel for later use.
The technologies are simple and fairly easy to maintain. In Washington and Oregon, it is legal to collect and store rainwater from a rooftop or other system without a water right if certain conditions are met.
Not every local jurisdiction permits rainwater systems for drinking and household use. Contact your local planning department to determine if permits are required.
If you plan to use your water for your landscape or garden, consider starting by harvesting water in the soil using passive water-harvesting earthworks, such as rain gardens. These are simple structures and strategies for “planting the water” before planting something else, or where you already have established drought-tolerant trees or native plants. For less hardy non-native vegetation, you may need to provide supplemental water in summer.
Match the quality of the water being harvested to the appropriate use: Stormwater from earthen slopes or impervious surfaces should be directed to trees and shrubs, not to vegetable gardens.
Consider replacing impervious surfaces like pavement with pervious material and landscaping. Pavers can replace pavement on your driveway and walks to increase infiltration of rain and runoff. A bioswale is another earthworks tool you can use to irrigate plantings, directing runoff from slopes or rain gutters to sunken raingarden areas. Vegetation, especially native plants adapted to your local area, can effectively serve as a “filter strip” that helps capture run-off before it reaches waterways and important habitat to fish and wildlife.
Your local conservation district can provide assistance with solving runoff problems.
There are online resources available from WSU and OSU Extension services, or contact your local conservation district for direct assistance.
Conservation Districts are local, non-regulatory public agencies charged with assisting landowners and residents with responsible natural resource management and stewardship. Hood River Soil and Water Conservation District in Hood River, Wasco County Soil and Water Conservation District in The Dalles, and Underwood Conservation District in White Salmon are available to assist with a variety of natural resource issues, including soil health, water quality, fish habitat, wildfire risk, forest management, noxious weeds, pollinators, wildlife, livestock and agriculture.
Tova Tillinghast and Barbara Bailey of Underwood Conservation District, with information from Innovative Water Solutions.