Posts Tagged: flooding

Jeffrey Mount and the Delta levee blues

Jeffrey Mount, a UC Davis geology professor and the Roy J. Shlemon Chair in Applied Geosciences, was included in “The Sacramento 100” — Sacramento News and Review’s 2010 round-up of the most influential, important and interesting people in Sacramento.

He was joined by an eclectic group of “interesting” characters, so whether being named on the list makes him notorious or famous is up to interpretation.

Jeff Mount

In any case, Mount was aptly described as “the man who knows everything about rivers in a region that owes its existence and continued survival to its rivers and Delta.”

As a local watershed expert and founding director of the UC Davis Center for Watershed Sciences, Mount was frequently called upon in the aftermath of the devastating levee breaks in New Orleans to estimate odds of a similar massive levee failure in the Delta.

The odds aren’t encouraging — Mount predicts a 64 percent chance of massive failure in the next 50 years. And some recent reports from the California Department of Water Resources suggest that is an optimistic estimate.

The strong late December storms sweeping through California had Mount keeping one eye on the levees and another on his kayak. So far this season, Californians have been lucky. But Mount doesn’t expect that luck to hold indefinitely.

The Sacramento-San Joaquin Delta supplies irrigation water for more than a million acres of agriculture in the Central Valley — some of the nation’s most productive farmland — and drinking water for two-thirds of California’s residents. But the levees that hold the Delta together are old and in crisis.

The 1,100-mile system of earthen embankments was built in the late 1800s and early 1900s to reclaim Delta marshland for farms. This creaky system of levees desperately needs a major overhaul. Over time, erosion, seepage and animal burrows have taken their toll. The levees have also been weakened by the gradual sinking of land behind the levees. Many of the Delta islands are now 25 feet below sea level.

Any major levee breach due to storm or earthquake could pull brackish ocean water into the Delta, contaminating irrigation and drinking water supplies and stopping the flow of water to the south and the Bay Area. Infrastructure such as rail lines, highways and gas pipelines would also be impacted.

The big picture of what could go wrong in the case of massive levee failure is scary if you stop and think about it, which has given Mount the name Dr. Doom in some circles. But Mount isn’t one to candy coat the situation. He was once quoted by a reporter that “New Orleans has lost the battle with the inevitable, and we will do the same.”

_{Jones Tract Flooding, 2004}

Flooding in Mossdale, 1997

Invasive reed arundo is choking state waterways

In the early 1800s, European immigrants introduced the fast-growing giant reed arundo (Arundo donax) into California to use the canes for musical instruments. The plants were also used for erosion control and the reeds used for thatched roofing. However, it has since naturalized and become a serious pest in the state's natural waterways.

Arundo can grow at a rate of four inches per day and can reach heights of 30 feet. It reproduces and spreads when sections of the stem or root break off and float downstream.

Dense stands of arundo displace native riparian species. The plant requires a significant amount of water, reducing fish, wildlife and people. In addition, clumps of arundo and the soil around their roots can break off, causing streambank erosion. The clumps can also create channel obstructions that lead to flooding.

Arundo is highly flammable and can quickly carry fire along waterways. After a fire, arundo quickly grows back from its roots. With other nearby plants burned by fire, arundo can spread even more quickly, leaving no room for native plants to recover.

Californians can help reduce the spread of arundo by taking the following actions:

• Learn more about arundo, including how to identify it
• Report sightings to local conservation groups
• Join local eradication efforts or help to start one
• If you own land with an arundo infestation, request help and provide access for control efforts

For more information, see the UC Riverside Center for Invasive Species Research website.

arundo

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