How Much Runoff In Washington Roof

So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall.

How much runoff in washington roof.

You can help solve our winter stormwater runoff problems by connecting a hose to the drain valve on your rain barrel or cistern and running it out into a lawn or landscape. When you look at the numbers it s surprising how much water you can collect every time it rains. 1981 2010 source national weather service. The study plan can be found at the link below.

Runoff of course occurs during storms and much more water flows in rivers and as runoff during storms. I do suggest hanging gutters as high as possible so that water does not over shoot them. If your roof plan is more complicated break it up into smaller. To get an idea how much water the roof of your own house might yield use the rainfall harvest calculator above.

Step 1 calculate the total area of your roof. Before you know what size rain barrels or cisterns to install you will need to calculate the average amount of rain runoff from your roof. For a rectangular house this is simply done by multiplying the length by the width of the roof. The anacostia watershed society offers a rebate of 10 to 15 per square foot to help defray costs of installing a green roof.

In this example 600 x 240 x 1 144 000 cubic inches of water. The system outlined below will walk you through the steps of determining your rain barrel sizes based on average roof runoff. For example in 2001 during a major storm at peachtree creek in atlanta georgia the amount of water that flowed in the river in one day was 7 percent of all the streamflow for the year. The rebate is available for residential or commercial buildings.

Also outlined are the steps to build your own rain barrel to collect water from your roof and downspout for all outdoor uses like watering and cleaning. For sample purposes a 55 gallon barrel will be used. To calculate the runoff from any given rainfall. Then just open the drain valve in october and let the barrel slowly drain out between big storms to slow our runoff all winter.

Just a half inch of rain falling on a 1 000 square foot roof will yield 300 gallons of water. Rain barrel supplies list. Take the dimensions of the footprint of your roof and convert them to inches. My own house with a metal roof of course is a 12 12 pitch and everything is just fine.