Fresno Bee Newsroom Blog

Fresno State study warns of climate effects on San Joaquin River

Two Fresno State professors say climate change will make the San Joaquin River’s annual runoff show up earlier — as much as six weeks earlier in the next century.

And one other thing:There will be a “significant decrease in annual stream flow,” said geology professor C. John Suen, who co-authored a study on the upper San Joaquin. Suen’s co-author was associate hydrology professor Zhi Wang.

The study, published in Hydrology Research, is more confirmation of findings in previous climate change studies, and it is not a pretty picture.

As water engineers and researchers have been saying for years, California’s reservoirs are built built to capture a gradual runoff from melting snow. More than half the state’s summer water supply is frozen in the snowpack each year.

If the state see more rainfall and earlier snow runoff, there could be big problems protecting communities and farms from floods.

In the San Joaquin Valley, the shift could be damaging for the multibillion-dollar economic base of agriculture.

This is about the place where the discussion turns to building larger reservoirs — such as Temperance Flat on the San Joaquin — or changing the way water and land are used. I’ll leave those issues to commenters here.

But Suen and Wang give us more reason to have the conversation.