Opinion Columns & Blogs

How Modesto and others can access more water despite climate change

The column about Farmland Working Group fighting sprawl mentions the two authors who have been tremendous long-term leaders in saving farmland, and there are many others who also deserve some credit. What is not discussed are the tremendous benefits that preserving permeable farmland presents for increasing water availability during climate change.

Global warming is inevitable and is well along already. It is irreversible, except over millennia, and will probably be much worse before society does anything about it. In California we can expect a great reduction, and perhaps elimination, of snow storage in the mountains; increased intensity of precipitation; and much longer and intense droughts. That is where wholesale preserving of permeable farm soils becomes imperative.

The ability to store water underground far exceeds the capacity of surface reservoirs, and water underground does not evaporate. But the only easy way to create that underground storage is to spread irrigation water over huge areas of permeable soils when floods occur.

Considerable research has already been done at UC Davis on storm flooding of farmland during winter. That will mean a great change from the past, when groundwater recharge resulted in part from flood irrigation in the summer and from stream infiltration, with water coming from snow melt and from water stored in reservoirs. Those sources will no longer be reliable, especially during long droughts.

The only source of water then will be from underground storage. That means farmers will have to be encouraged to flood during the winter for their own benefit as well as for the good of the public at large. Financial help may be needed for some farmers if the recharged water is primarily for the benefit of others.

The state of California is notorious for lack of understanding of hydrology, especially that a well affects the water table many thousands of feet around it. Politicians are responsible for the problem, not professional hydrologists on state staff.

Just a few years ago a Modesto city planner said at a public meeting that he knew little about hydrology, even though water is indispensable to the city’s survival. That situation absolutely must change.

The state requires that local politicians plan for specified growth, ignoring the need for water and saving permeable farmland. It is sheer stupidity, but nothing new.

Local and state politicians are noted for only short-term planning so they can stay in office. Few businesses care about longer-term environmental effects. The politicians need some justification from well-known scientists to pass realistic rules on planning for much worse global warming yet to come. That certainly must include preserving any permeable soils potentially used for charging groundwater and not yet paved over.

Global warming is certain to get worse, and we must plan accordingly.

Modesto’s Vance Kennedy is a retired U.S. Geological Survey scientist. He wrote this for The Modesto Bee.

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