Flooding in the Time of Drought
It may seem strange to read about flooding in California while the state is going through its fourth year of a record drought and the government is curtailing watering practices. The downpours of last December, however, should remind us that floods can occur any time after heavy rains no matter how little rain otherwise falls. According to the California FloodSAFE Program, the last four years of drought have averaged sixty million dollars a year in flood damage. For example, the December 2014 rains led to widespread flooding in the state, resulting in the evacuation of nearly 1,000 homes and the closing of several major highways. Elsewhere in the U.S., floods in drought-stricken Texas and Oklahoma recently brought death and disaster to the citizens of those two states.
Flooding can take many forms: the result of a river or stream surpassing the flood stage, usually from heavy rainfall or melting snow; flash floods caused by heavy rainfall often overwhelming small creeks and streams; and areal flooding, usually the result of a prolonged rainfall. In all of these events, the danger is made worse by the floodwaters rushing over dry, drought-hardened ground.
According to experts, the danger of flooding in California will increase whether there is a drought or not. There is a consensus among scientists that climate change is magnifying the risks of future droughts and floods and that California’s wet season will become shorter and sharper. Storms are likely to be more intense and winter precipitation will more likely fall as rain rather than snow.
Already we have seen that wildfires spurred by the drought and higher than normal heat have threatened many areas of California with floods and mudslides following heavy rains. The state Department of Forestry and Fire Protection, citing a major increase in wildfires this past winter, warns that the drought has made wildfires a year-round threat.
In March, California Governor Brown announced that $660 million of a billion dollar drought relief program would be spent on flood control measures: “With climate change and global warming, there will be more extreme weather events… All of a sudden, when you’re all focused on drought, you can get massive storms that flood through these [river and stream] channels and overflow and cause havoc.”
Enhancing flood protection is, of course, a major goal of River Partners. Our efforts to restore floodplains to their natural functions include working with governmental agencies to reconnect river channels to floodplains by moving back or breaching levees, thus mitigating storm surge. Meanwhile, restoration work on the floodplain eases the consequences of limited rain by providing refuge for drought–stressed wildlife and holding flood waters long enough to allow seepage into the underground aquifer.
The above article originally appeared in the Spring 2015 issue of the River Partners Journal.