Rainwater Harvesting for Drylands and Beyond by Brad Lancaster

Author:Brad Lancaster
Language: eng
Format: epub, pdf
Publisher: Rainsource Press
Published: 0101-01-01T00:00:00+00:00

Fig. 5.3. Late-winter garden grown entirely from rainfall and roof runoff harvested in 1,300-gallon (4,920-liter) tank in 2005.

Our original cistern has a 1,300-gallon (4,920-liter) capacity. We selected this size after calculating average annual roof runoff, assessing our water needs, and determining the resources we wanted to commit to the system. We knew that we did not have enough runoff to meet both domestic water needs and those of the garden and landscape, so we reduced water demand and increased supply by implementing conservation strategies such as installing a composting toilet, installing a greywater system to reuse drain water in the landscape (see figures 5.4 through 5.7 and the greywater chapter in Rainwater Harvesting for Drylands and Beyond, Volume 2), and replacing some water-hungry exotic plants with drought-tolerant natives. This helped, but we still didn’t have enough roof runoff to meet all our water needs. So we decided to use the roof water just for irrigation as part of an experimental start-up cistern system. Wanting to keep the tank affordable—and under 1,500-gallon (5,700-liter) capacity—we decided to size the tank to capture the runoff only from the 650-square-foot (60.4-m2) section of roof that sloped toward the garden, rather than the whole roof. From that section of roof we then wanted to be able to store at least all the runoff from a 3-inch (76-mm) rainfall event (or two 1.5-inch [38-mm] summer storms hitting a week-or-so apart). Using this information, we calculated we needed a 1,300-gallon (4,920-liter) cistern. (See Equation 6 in appendix 3 for this calculation.)

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.