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El Niño: Fresno Area Officials Prepare For Flooding

Aug 18, 2015

There’s been a lot of noise around El Niño in the news lately. We don’t know if it’ll cure California’s drought, but in places prone to flooding officials are already prepping for the worst.  FM89’s Ezra David Romero reports on why officials hope to dig deep to prevent flooding and restore the aquifer.

At the moment the mood is hopeful at the National Weather Service Forecast Office in Hanford.   

Jerald Meadows explains that flooding could happen if winter storms hit the region.
Credit Ezra David Romero / Valley Public Radio

"National Weather Service, this is Jerald How may I help you," says Jerald Meadows, warning coordination meteorologist with the San Joaquin Valley Weather Forecast Office. 

A strong El Niño could bring storms to our dry part of California. Meteorologists like Meadows are looking to the sky for signs of what his peers say could be the El Niño of El Niño’s.

“The million dollar question is how strong the El Niño’s actually going to be," Meadows says. "Most of our forecast models are indicating it’s strengthening.”

Even though this could be the strongest El Niño on record, exactly where storms hit produced by it are up to debate.  Dependent on circumstance Central California could receive a significant amount of rain and snow, but even if one variable is off then precipitation could mainly stay in Southern California, leaving out the most parched regions of the state.    

“Assuming the track of the storms shift south as we typically expect in a strong El Niño, we could see more moisture, more storms moving across us," Meadows says. "But those storms still have to develop and get brought across the jet stream and into our area. Assuming those do there’s potential for heavy rains.”

The National Weather Service Office in Hanford in the center of California keeps an eye out on storms and other weather related events across the state.
Credit Ezra David Romero / Valley Public Radio

That heavy rain could mean heavy flooding. That’s why officials in places like Fresno are doing something you wouldn’t expect in the middle of a drought.  Digging holes in the ground to store water in order to prevent future floods.

Fresno has over 160 ponding basins and canals connecting them. You know those sunken grassy community parks that fill up with water when heavy rains fall. I’m at one of these sites with Alan Hofmann.

"El Niño that affects the southern half of the state isn't going to be as effective as something that would hit the entire state. I would hope that first the El Niño pattern hits the Central Valley." - Alan Hofmann

“So we’re at what we call basin BS off of Fowler near just south of Mill Ditch," says Hofmann, the general manager for the Fresno Metropolitan Flood Control District.

Right now there’s no water here. A backhoe is filling up semi-trucks with 10,000 gallon containers full of soil so if heavy rains happen this basin will be able to collect runoff from surrounding neighborhoods. They want to make the basin bigger. Right now the basin could hold 60 acre feet of water, but when the digging stops it’ll have a capacity of 300 acre feet. That’s like 5 times bigger, kind of like going from a swimming pools worth of water to a small lake.

The thing is most of these storm water management basins only hold about six inches of rainfall collected over a two square-mile span. The problem is it takes time for that water to percolate back into the ground restoring the aquifer under the city. So if the region is hit by back-to-back storms this winter as a result of the looming giant El Niño that’s predicted then places like Fresno could be in trouble.

“Any time we get more than the six inches if the basins full and we get a rainstorm the only place for it to go if we can’t get rid of it soon  enough is it start filling up neighborhoods wherever the lowest part of our collection system is," says Hofmann. "That’s happened on a number of occasions.”

There are over 160 ponding basins across Fresno. The capacity in each one is measured through sensors in the basin.
Credit Ezra David Romero / Valley Public Radio

That’s why the flood control district Hofmann manages is working around the clock to make sure these ponding basins are at the right depth and have fully functioning pumps.

"We obviously listen to what weather people are saying about the magnitude of the potential for the storms. But it's not like I can change my system instead of taking six inches to take 12 inches. It is what it is."
When storms hit Fresno Alan Hofmann work to make sure the region doesn't flood.
Credit Ezra David Romero / Valley Public Radio

  "We obviously listen to what weather people are saying about the magnitude of the potential for the storms," Hofmann says. "But it’s not like I can change my system instead of taking six inches to take 12 inches. It is what it is.”

Hofmann would like to see a new standard when it comes to the depth of these basins. He says a standard of eight inches of capacity in all 160 plus ponding basins would be ideal to avoid flooding.

He remembers the aftermath of the last few big El Niño's.

"They talk about the 83 El Niño and the 97 and El Niño and during that time our system was very challenged," Hofmann says. "Ponding basins were full and filling up in neighborhoods and we were just trying to find places to move the water as quick as we can."

Even with those  concerns about flooding he’s still optimistic about El Nino, he just hopes it doesn’t veer too far south.

“El Niño that affects the southern half of the state isn’t going to be as effective as something that would hit the entire state," Hofmann says. "I would hope that first the El Niño pattern hits the Central Valley.”

A wet season in the region means fuller reservoirs and possibly a larger snow pack. If the state’s lucky to get both we could witness the first bit of relief from this four year drought.