The spring rain has been wonderful and we could get super lucky and be gifted a few more downpours before summer settles in.
Every drop counts when you live in a region like ours that averages 18 inces of rain a year. Rainfall statewide for May is at just 66 percent of normal.
It won’t be long before we notice the increase in our water bills due to the recent utility bill increase combined with growing demand to irrigate as temperatures rise and soils dry out. This reality can serve as inspiration to maximize the precipitation we are blessed with. By practicing good soil stewardship through amending our soils, generous mulch and planting trees and shrubs with low water needs (once established), we can maximize the precipitation we get. Every one of us fortunate enough to have a roof over our heads is additionally blessed with the ability to collect the rain that falls and save this water for irrigation and reduce demands on city water.
A 5-gallon bucket can collect a little roof water, while a 55-gallon container (or even 3,000 gallon tanks) are possible and permitted.
Recently, I was looking for a solution to avoid schlepping two 5-gallon buckets of water down a steep slope a few hundred yards to water young trees away from a spigot. Several years ago I had acquired a “reject” 65-gallon roll cart destined for the landfill. I was using it to store plastics for “plastic roundup” events from yesteryear. In its first life this “cart” was for organics. Its second life was storage for plastic. For its third re-use it collects rain water off a small (11- by 16-foot) shed roof to water trees in a remote spot.
Karen Taylor helped me with the project. These details may offer inspiration to you to try rainwater harvesting at your locale:
The best rainwater quality for harvesting can be obtained from metal, clay tile and slate rooftop surfaces. For the simplest of collections, a gutter and downspout into a container is all one needs. For larger tanks, include a first-flush diverter. This works when the gutter and downspout carry water to the first flush diverter. It uses the first few gallons of water to remove dirt, leaves and bird poop away.
A flat, level and compacted pad is required for a tank. Water is heavy (1 gallon weighs 8.34 pounds). If you have a full 55-gallon drum, it weighs more than 450 pounds and needs a stable base.
An overflow valve is very important. Always size the overflow the same size (or larger) than the inlet pipe. Overflow can be as simple as directing a hose attached to the tank that will divert the excess to another spot. A rain garden is a perfect place to send the overflow. Installing a hose bib for easy bucket filling or in a watering can to use to water plants during the dry months works dandily!
To figure out how much rain falls on the roof during our rainy season, here are the calculations: roof square footage times average rainfall in feet times 7.48 (gallons per cubic foot). Measure the footprint of the roof (slope does not matter, just the flat footprint) and calculate the square footage of the catchment area. Figure out yearly rainfall in feet by dividing the number of inches by 12. Once you have multiplied the roof square footage times feet of rain, that will be cubic feet of area. Multiply the cubic feet by 7.48 (yes, one cubic foot can hold 7.48 gallons!) to get how many gallons of rain fall on the roof. Or, as a general rule, 1,000 square feet of roof sheds approximately 600 gallons of rainwater per 1 inch of rainfall.
It is legal to catch rainwater as long as it is collected from the roof before it touches the ground.
If you need professional guidance collecting rainwater, Karen Taylor (SiskiyouPermaculture.com, 541-482-7909) or Ken Laidlaw (Rogue Water Solutions, 541-488-3500) can help you make it happen.
On a related note, the city of Ashland is offering two graywater laundry-to-landscape workshops on May 19 and June 16. For more information, go to www.ashland.or.us/graywater or call Julie Smitherman at 541-552-2062.
— Risa Buck has served on the Ashland Conservation Commission and in waste prevention education for more than a dozen years. You may reach her through firstname.lastname@example.org. Find past WasteNot columns online at bit.ly/bit.ly/rbwastenot2.