floodwater harvesting

    Published: December 31, 2015

    Combating Droughts with Floods

    It seems counterintuitive, but California’s drought has made flooding more likely. The state’s soil, baked into a hard crust, repels water faster than it can soak it up. The earth has, in many areas, become hydrophobic: Water simply beads and runs off.

    This means that when snow melts or rain falls, water runs into local rivers instead of soaking into the ground, swelling them to the extent that they burst their banks and flood surrounding areas. The floodwater is wasted. But what if that doesn’t have to be the case?

    A bold new plan proposes redirecting floodwater onto farmland where it could soak into the fields and replenish agricultural groundwater. The California Water Foundation began testing this idea in the San Joaquin River Basin with impressive results.

    The theory is simple enough. Statewide, farmers use an average of 34 million acre-feet of groundwater a year. In return, aquifers and groundwater sources recharge at an average rate of 31 million acre-feet a year. This means agriculture is running a water deficit, but not a particularly large one. Capturing floodwater would easily make up this outstanding amount.

    In the San Joaquin study, researchers studied three counties with an average groundwater deficit of 250,000 acre-feet a year. The average floods in the same region produced an annual average of 253,400 acre-feet a year.

    Mathematically, this means the state has enough floodwater to make up any groundwater deficit, but problems exist. For starters, the infrastructure of ditches and channels in the three counties cannot divert that much water in their present state. Floodwaters could only be diverted to flat farmland and would have to be diverted to areas where the ground was not contaminated with pesticides, salt, or fertilizers that could contaminate groundwater. Even so, research suggests diverting floodwater could at least alleviate local groundwater deficits.

    Location is another problem. One of the most flood prone regions in California is the Sacramento River in the northern portion of the state. Northern groundwater is relatively stable compared to the south, but diverting floodwaters southward presents insurmountable challenges.

    The study may not completely solve the state’s groundwater debt but certainly serves as a reminder of the importance of inventive approaches to water reclamation and conservation. For Pelican, this has meant pouring research and development into our NaturSoft® Water Softener Alternative with Salt Free Technology.

    Salt-based water softeners waste up to 150 gallons of water every week. This level of waste was unacceptable to us, especially as the wastewater was loaded with environmentally damaging chlorides. NaturSoft® systems produce zero wastewater and require no electricity to operate, making them an ecofriendly solution to your hard water problems.