Experts looking past levees for flood control
STOCKTON — Think outside the levee.
As concerns about the state’s aging flood-control infrastructure grow, experts are seeking ways to address the San Joaquin River’s big-time risks in less traditional ways.
We’ll still need to strengthen our levees and dams in the future, of course. But a recently released draft plan contains some new and creative ideas that could help save hundreds of lives and prevent billions of dollars in damages.
There may be other benefits, too: Improving conditions for endangered fish, reducing pollution, or providing new recreational opportunities.
Most noticeably for Stockton, perhaps, the plan calls for turning long-dead Mormon Slough back into a functional waterway where it passes through the city, even adding nature trails and bike paths. This would take some pressure off the Calaveras River and, conceivably, reduce the scale of costly levee improvements.
“It would change the whole image of the channel. It has been kind of forgotten,” said Jim Giottonini, director of the San Joaquin Area Flood Control Agency, which has pushed the project for decades.
The plan also promotes the long-discussed widening of a flood bypass at Paradise Cut near Lathrop, which could lower the San Joaquin River about 2 feet in Lathrop and Stockton. The bypass would shunt some water into the south Delta, avoiding the downstream urban levees.
One of the reasons that the San Joaquin is considered especially vulnerable to future floods is because it doesn’t have bypasses such as those along the Sacramento River, to the north. Paradise Cut would not only provide such a bypass — albeit a small one — but it would also preserve habitat for sensitive species such as the Swainson’s hawk while still allowing the land to be farmed when it’s not underwater.
Farther south, the plan would allow for the river to intentionally flood low-lying fields in certain areas, which also could take at least some burden off downstream levees, though it’s unclear how much.
An unintentional levee failure at the San Joaquin River National Wildlife Refuge near Modesto last February brought the river down about a foot at Vernalis, eight miles away. That provided a bit of relief, at least temporarily.
Flooding those areas in a planned, strategic way could make a real difference, said John Carlon, manager of the nonprofit habitat restoration group River Partners.
“This can buy time for people to evacuate,” he said. “I think there’s going to be a lot of public safety benefit.”
Still more ideas: Taking climate-change induced floods on the Calaveras River and storing them below ground, which would address two problems at the same time; using better forecasting tools to predict when dams should release or hold back water; and improving public warning systems.
These alternatives won’t be enough, experts say. Levee projects will remain critically important. The levees along the San Joaquin are inconsistent at best; the state plan calls for major upgrades along the western flank of Stockton to protect against a potential surge of water from the Delta.