By Peter Anderson
Extreme drought tests our assumptions about a predictable future and now that the well is running dry, we understand the worth of water.
Sixty percent of California and ninety percent of the southwest are in severe drought.
The biggest impacts are likely to occur from increased agricultural groundwater pumping to partially compensate for reduced surface water supplies and deep aquifers being pumped dry. We are seeing the effects of aquifer depletion in the Carneros grape growing region of the Napa Valley as salt water intrudes from San Francisco Bay. Salt water intrusion is also expanding in the Carmel Valley, the Salinas Valley and elsewhere.
A friend’s deep well in San Rafael just went dry. No more water for his orchard. Our local creeks are drying up. Our forest ecosystem is at risk as more drought resistant native trees succumb to prolonged drought.
Water rationing is now mandatory in Marin. Our local water utility is stressed financially as it copes with the dual threat of drought and fire. The cost of water is rising.
This is what we knew in 2015: January of that year was the driest in California since record keeping began in 1895. Scientists analyzed tree ring samples from native blue oaks and reconstructed rainfall back to the 13th century. According to their findings, there had never been a three year period in California during which the temperatures had been as high and rainfall as low as they were between 2012 and 2014.
And here we are in 2021. There is no end in sight to this drought. What can we do?
One fifth of electrical output in California is consumed by pumping and processing water. The Marin Municipal Water District is number one in Marin for using electricity.
By cutting water usage we can reduce our carbon footprint.
By collecting rainwater we can reduce our water bill.
If we do this to scale, collect rainwater and recycle waste water, we can leave water in the reservoirs – for drinking, bathing and fire repression.
If only 326 people collect 1,000 gallons of rainwater in their cisterns, that would add up to one acre foot or 326,000 gallons of water that would be left in the reservoirs for drinking. One acre foot of water will provide 60 gallons of water for one day to 5,433
people. The rainwater collected in our cisterns could be dedicated to a valuable shade tree at risk or provide a source of water for birds and bees.
Who is leading the way? Rainwater catchment is required for every residence on the island of Bermuda. Each house is required by law to have and maintain a cistern capable of storing enough rainwater to sustain a family of 4 for a year. The states of New South Wales and Victoria in Australia require all new construction to be plumbed for rainwater catchment and grey water recycling. Fifty percent of the homes in Australia capture rainwater.
In the US, Tucson, Arizona, is serious about rainwater harvesting. The city’s water utility, Tucson Water, offers generous rebates to its customers to subsidize the installation of rainwater catchment systems. Data confirms that residential rainwater harvesting has reduced the city’s overall potable water demands.
Tucson is the first city in the US to say that all new commercial properties must be designed to use rainwater. City managers say that behavior changes when people use rainwater instead of city water. They treat water as a precious resource.
We now understand the existential threat of extreme drought and we have examples of appropriate responses. We need to collect our rainwater and it must become the law.
The consequences, if we fail to do so, are both terrifying and increasingly inevitable.