Message from the Board Chair
By Irv Schiffman
As I write this column, California appears to be heading into its third year of drought, although a rainy February may be a harbinger of good things to come. However, after two back-to-back extremely dry years, even an extremely wet winter might not end California's water shortage.
A drought is a natural phenomenon caused by changes in weather patterns resulting in less than normal rainfall. While we cannot manufacture more rain, we can manage our floodplains to help mitigate some of the consequences of drought.
Such mitigation includes maintaining the cleanliness of waterways and groundwater. Our restoration areas are frequently adjacent to working farmlands and the vegetation that we plant forms a natural buffer that filters agricultural runoff and keeps non-point source pollutants, particularly nitrogen, out of the river and the subsurface water supply.
When delivery of river water decreases as the result of drought, groundwater becomes that much more important. An increased recharge of subsurface water takes place when levees are moved back from the river, thus enlarging the flood plain and allowing floodwaters to wash over the newly restored acreage. River Partners fully supports levee setbacks as a means to reduce flood dangers and to reinstate the natural functions of the floodplain. We have restored or are restoring hundreds of acres of floodplain land at the confluence of the Feather and Bear Rivers and along the Feather River south of Marysville where levees have been set back 600 feet in the first instance and almost a half mile in the second.
Water conservation is, of course, essential during drought periods (and otherwise) and the replacement of flood threatened agricultural fields and orchards with riparian vegetation reduces the need for pumping groundwater. By retiring such crop or orchard land we are retiring agricultural irrigation on that property. In most areas of California, for example, a mature walnut orchard has the potential to use about 42 inches of water per acre or about 290 gallons of water for each pound of nuts produced in a 2-ton orchard.* We irrigate our plantings only in the first three years and then they are on their own.
More frequent floods and droughts are likely consequence of climate change, requiring greater attention to be paid to the complex of problems that arise when rivers are disconnected from their floodplains. California does not have a statewide riparian policy regarding floodplains and to a great extent local governments decide how land next to rivers shall be used. It is time for the state to formulate a plan to preserve and restore the numerous and beneficial functions of Central Valley floodplains.