The act of water harvesting is not a way of gardening, it is a way of life. The importance of water harvesting is simple…to create a sustainable way to use rain water. If created correctly, your water harvesting area could be used not only to house a beautiful garden, but for your showers, and even drinking water. The benefits are enormous from creating a water harvesting system. By simply setting up tanks in strategic places, you can have yourself a wonderful and quite useful water harvesting system…in your own backyard! First, allow me to compare the benefits of creating a system just out of earthworks, or the benefits of adding cisterns to collect water.
Comparing Earthworks and Tanks:
- Water uses:
Earth works: Provide large quantities of high-quality rainwater to garden and landscape
Cisterns: Provide water for drinking, washing, fire control, and supplemental irrigation. Click here for more details on supplemental irrigation:
2. Water collection areas:
Earth works: Can collect water from roof, streets, vegetation, bare dirt, greywater drains, air conditioner condensate, etc. Click here for the definition of greywater:
Cisterns: Need relatively clean collection surface (typically metal, tiled or slate roof) located above the cistern.
3. Water storage capacity:
Earthworks: Very large potential to store water in soil
Cisterns: Limited to size of tank
Earthworks: Inexpensive to construct and maintain. Can build with hand tools
Cisterns: Cost varies with size, construction material, above or below ground placement, self built, etc.
Earthworks: Do not locate 10 feet away from a wall or building fountain. May be very difficult if garden is in very small yard, with adjacent nearby roofs.
Cisterns: No limit to where you can place the cisterns. Can be used in very small yards with adjacent nearby roofs.
6. Time period water is available:
Earthworks: Water available for limited periods after rainfall depending on soil type, multch, climate and plant uptake. Click here for more information on multch and its uses:
Cisterns: Water available for extended periods of time after rainfall
Earthworks: Work passively, require some maintenance after heavy rainfalls
Cisterns: Maintenance required, must turn valve to access water and may need pump to deliver water
8. Erosion Control:
Earthworks: Very effective
Cisterns: Can assist with erosion control
9. Grey Water Collection:
Earthworks: Very effective at harvesting grey water from household drains
Cisterns: Not appropriate to harvest grey water in tanks due to water quality issues.
10. Water quality impacts to environment:
Earthworks: Pollutants in grey water and street runoff intercepted in the soil stay out of regional waterways
Cisterns: Less impact than Earthworks to the broad environment
11. Impacts on urban infrastructure and flooding:
Earthworks: Can capture large volumes of water, reducing need for municipal water (click here for municipal water definition: ), storm-water drains, storm-water treatment and decreasing of flooding.
Cisterns: Can capture low to moderate volumes of water, reducing demand for municipal water, storm-water drains, storm-water treatment and decreasing of flooding.
12. Groundwater recharge:
Earthworks: Sometimes can recharge very shallow groundwater tables
Cisterns: Not an efficient use of tank water