Roof Rainwater Runoff

A 1 000 square foot roof can produce more than 600 gallons 2 271 2 l of runoff for every 1 of rain that falls on it.

Roof rainwater runoff.

If you have heavy runoff from roof downspouts and neighboring properties redirecting or capturing runoff can provide better control. For a large roof it is recommended to have drains placed at multiple locations within the area of the roof. Install a rain barrel or cistern to catch stormwater runoff from roofs. How water runs off a roof depends on the amount of rainfall and how quickly it needs to drain.

Use a shallow gravel filled trench to catch and slow runoff especially at the base of a slope or alongside a driveway or patio. The drainage system of any roof can be located at the edge or in the middle of the roof. If your downspouts are connected directly to a storm drain disconnecting them is the single most important step you can take to reduce runoff. Plant a rain garden.

Use this water to irrigate garden plants. To calculate the runoff from any given rainfall. In this example 600 x 240 x 1 144 000 cubic inches of water divide by 231 to get the number of gallons because 1 gallon 231 cubic inches. Earthminded diy rain barrel diverter kit water barrel rain barrel adapter kit includes spigot and downspout diverter for 3 x 4 inch downspouts f rn097 4 6 out of 5 stars 183 39 99 39.

These techniques will minimize the amount of water that accumulates or that causes erosion in the problem area. Multiply the two figures together to obtain the square footage of your roof step 2 determine the percentage of water collected from each downspout p. The answer is about 623 gallons. Rainwater runoff from your roof contains a mix of materials deposited by pollution and animals as well as chemicals used in the manufacture of the shingles.

While this is a normal aspect of roofing and gutters water that pours off of a roof and drenches an area like a door stoop or porch not only makes these spots slippery but water falling. Take the dimensions of the footprint of your roof and convert them to inches. So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall. Measure along the length of the house or building and along the width of the house or building in feet.

For slopes consider creating a dry creek to catch slow down and direct runoff perhaps to a rain garden see below. Step 1 determine the footprint of your structure f in square feet. Divide 100 by the number of downspouts in order to obtain the percentage of water collected from each downspout. Count the number of downspouts coming from your roof.