It is raining in Southern California. Traffic snarls. Electricity fails. Raw sewage runs into the sea. TV stations break into regular programming for special reports: 'Yes, Chet and Mindy, it's coming down hard here in Covina.'
In Ecology of Fear, Mike Davis describes the Kona storm of January 1995: 'Sinkholes mysteriously appeared in front yards. Waterspouts danced across Santa Monica Bay. Several children and pet animals were sucked into the deadly vortices of the flood channels. Reckless motorists were drowned at flooded intersections .Million-dollar homes tobogganed off their hill-slope perches or were buried under giant landslides.' Davis observes: 'For generations, market-driven urbanization has transgressed environmental common sense.' Floodplains have been turned into industrial districts and housing tracts, and 'monolithic public works have substituted for regional planning and a responsible land ethic.'
Average rainfall in Los Angeles is pegged at 15.1 inches. But, as Davis points out, ' nothing is less likely to occur than 'average rainfall.'' Last year in Southern California was the driest in 130 years. Since July, however, twice the 'average' amount of rain has fallen on Downtown L.A. Should we celebrate? Not yet. Bill Patzert, climatologist for JPL, explains that snowpack, groundwater and reservoirs all need to be recharged. ('The Dry Forecast Reigns,' by Molly Hennessy-Fiske, Los Angeles Times, January 22, 2008.)
Only 2.5 per cent of our planet's water is considered fresh water. Most of this is locked up in glaciers and ice caps, at least for now. Rainwater is a precious resource, especially in drought-prone areas. How can we let so much of it simply run into storm drains, then out to sea, picking up pollutants along the way?
Rainwater collection goes back almost 3,000 years. The title of an article in the Mid-County Post (Capitola, CA) tells the current story, one hopes. 'Rediscovering Rainwater: Rain Harvesting Comes of Age-Again.' In Southern California, Santa Monica has implemented a water recycling and storm runoff diversion program. Santa Monica's Municipal Code of Ordinances includes an Urban Runoff Mitigation Plan. The city also allows expedited permitting for LEED-certified building projects, taking weeks off the approval process. LEED means Leadership in Energy and Environmental Design. Part of the green building process involves rainwater catchment.
The website of TreePeople describes construction of an Open Charter Elementary School (W. 77th Street) stormwater project. Before the project began in 2003, the mostly paved campus flushed polluted runoff into Santa Monica Bay. Asphalt was removed for a stormwater facility, storing rainwater underground and making room for a grassy playing field.
What can individuals do? First, we can plant and care for trees on our property. A large front yard tree can intercept 760 gallons of rainfall in its crown, reducing runoff. Second, the next time we need to repair or replace a driveway or other paved area, we can choose a permeable surface material-one that allows water infiltration. Not every inch of a driveway or parking area has to be solid concrete, does it? Third, we can harvest rainwater in rain barrels.
The simplest way to do this is to put a rain barrel under a rain gutter downspout and use the naturally soft water collected to water sensitive indoor plants. The barrel should be covered between uses. Mesh or screen over the top of the barrel will keep out silt and leaves when water is pouring in. The next step up the ladder of complexity would be to collect water in two or more barrels connected together near the bottom with pvc pipes or hoses. One can buy 50-80 gallon rain barrels at some garden- supply stores, and some online gardening sites sell cisterns and other, more complex, equipment.
Rainwater collected from the roof of a house usually picks up little contamination. Keep your roof as clear of debris as you can. Old tar and gravel or old asbestos shingle roofs create too much contamination for rainwater harvesting. Treated cedar shakes are not good either. Rain gutters joined with lead soldering or painted with lead-based paints are not recommended. Finally, the barrel you use should be a food-grade container. Common trash cans will not withstand water pressure for long. One inch of rainfall provides approximately 600 gallons of water from a 1,000 square foot catchment area. A roof catchment area is equal to the total square feet of its building plus the extension of its eaves.
Rainwater is the best kind of water to use in the garden. Let's capture as much of it as we can. We can cut back a little on both municipal water use and stormwater runoff. A few resources are: rainbarrelguide.com, Harvesting Rainwater for Landscape Use (http://cals.arizona.edu/pubs/water/az1344.pdf) and Rainwater Collection for the Mechanically Challenged, by Suzy Banks and Richard Hemichen.