A rainwater collection barrel can prevent flooding on your property, supply water for dry spells and lower your water bill.
Rainwater collection barrels are designed to collect rainwater runoff for storage and later use in home gardens. Rainwater and groundwater are so scarce in some areas of the western United States that rainwater collection is encouraged, if not required by law. In areas of uneven topography such as Downers Grove, Illinois, planning boards require stormwater abatement as part of local permitting processes for construction. Rainwater collection barrels should accommodate both the volume of water of its catchment area and the water demand of the garden or landscape. Does this Spark an idea?
Instructions
1. Measure the size of the catchment area, including the gutters and downspouts. A catchment area is typically a roof or surface that collects rainwater. Multiply the length and width of one section to calculate the area in square feet. Locate and document the number and size of downspout outlets. Write down all sizes and areas.
2. Refer to rainfall tables and maps to determine maximum rainfall. These tables are usually provided by local or national weather bureaus. Use this value to determine your designed storage capacity in gallons with a formula. Multiply the area of the roof by the rainfall feet multiplied by a conversion constant of 7.5. The constant converts from gallons to cubic feet in volume. The answer is a volume in gallons, which is your maximum capacity. Losses from absorption or evaporation will slightly reduce practical yield.
3. Measure the future location of the rain barrel's storage area to match the designed demand, quantity and size of barrels. Typically, 55-gallon barrels each will need a 2-foot by 2-foot square if installed vertically. Thirty-gallon barrels will fit in an area 18 inches square. Stabilize the barrel base to take the weight of a full barrel.
4. Document the water demands of your garden and landscaping. Refer to experience and calculate accordingly. For example, the water that a lawn sprinkler uses in half an hour can be determined by the rate of flow multiplied by the time. This answer is multiplied by the frequency of watering and can be used to calculate the anticipated demand over the length of the watering season.
5. Determine the rate of flow by timing how long it takes to fill a gallon container. Assuming one gallon per minute of flow, 30 gallons would be used in a half-hour. If you water four times a month over six months of spring and summer, you would need 720 gallons of water over six months. Use this demand in gallons to size your storage capacity in increments equal to the capacity of your barrels.
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