A pretty thorough analysis of flooding Delta islands

A couple of years ago, Robyn Suddeth, a graduate student at UCD’s Center for Watershed Science, looked into the “Policy Implications of Permanently Flooded Islands in the Sacramento-San Joaquin Delta.”

The Center for Watershed Sciences is the academic home of Jeffrey Mount and Jay Lund, both of PPIC fame. So it isn’t surprising that Suddeth’s paper is based on the assumption that of course the future of the Delta will include more flooded islands.

There are many possible negative effects of permanently flooding deeply subsided islands, and Suddeth, with scholarly honesty, lists them:

  • Invasive species expansion, depending on location in the Delta, depth, proximity to the Sacramento and San Joaquin Rivers, size, tidal influence, and other factors.
  • Water quality degradation, especially salinity intrusion, again depending on location and relative exposure to river flows and tides, leading to treatment costs for exporters, water shortage costs for upstream users, and degradation of farmland.
  • Seepage on neighboring islands and wave action against neighboring levees, depending on “location and configuration – position relative to wind direction, breach locations (and hence flow velocities), and the locations of sand lenses” – porous areas through which water can move.

With all these good reasons not to flood more islands in the Delta, you’d think the idea would be taken off the table.

Nevertheless, from a Center for Watershed Sciences perspective, some islands are not economically sustainable; flooding is inevitable; planned transitions to open water are better than unplanned, catastrophic transitions; and those who resist experimenting with flooded islands are guilty of inertia.

(Since we already have Delta islands that have flooded and not been reclaimed, one wonders why we need further experiments.)

Since Suddeth is persuaded that planned flooding is as good idea, the question is how to deal with obstacles. She considers these in three categories.

The first category involves ensuring legal authority. Suddeth argues “that if an island better serves the public interest as open water, then planned and intentional breaching could be justified under the Delta Flood Protection Act [of 1988], especially if a catastrophic breach might harm both public and private property.” She sees the 2009 legislation as probably giving the Delta Stewardship Council the necessary legal authority to “selectively reorganize Delta land use.”

But others, like Dr. Robert Pyke, think the language on co-equal goals (“the co-equal goals shall be achieved in a manner that protects and enhances the unique cultural, recreational, natural resource and agricultural values of the Delta as an evolving place”) means that “there may be some evolution in land use, but it is state policy to protect and enhance the Delta pretty much as it is.”

A second category of state actions considered by Suddeth involves acquiring permits to experimentally flood an island. She mentions the different water and environmental quality acts that would govern this permitting, and she seems as impatient with their constraints as the most vocal Central Valley congressional representatives.

Suddeth suggests changing the standards and/or allowing short-term violations of water quality standards. She mentions the “rigidity of the Endangered Species Act and its conflict with experimental or adaptive management approaches.”

When we think of the pre-reclamation Delta, we don’t think about the mosquitoes that would have thrived in tidal wetlands. Plans to add more wetlands will pose both a health risk and an increased workload for local vector control.

Suddeth says this issue was raised at a Bay Delta Conservation Plan scoping meeting. But she classes it with “an almost limitless number of [CEQA-related] issues that might mire the progress of an experimentally flooded island.”

We wouldn’t want human health concerns to get in the way of this kind of experiment.

“As with the Endangered Species Act,” says Suddeth, “the state’s best strategy with CEQA and NEPA will be to attempt to preempt possible concerns with a detailed, well thought-out plan informed by all relevant scientific knowledge.” Whose science?

The third category of state actions that Suddeth discusses relates to dealing with landowners. She notes that the state might face liability related to the impacts of a flooded island on neighboring private property. She tries to argue that “intentional flooding of several Delta islands has a flood control component in that money previously spend on levee maintenance on those islands is then freed up for perhaps more effective maintenance on remaining islands.” But the argument isn’t convincing. She concludes that “State policymakers will have to seriously consider the inverse condemnation and nuisance laws as they plan for a transitioning Delta, and do their best to preempt such claims with preventative mitigation.”

It is hard to talk seriously about mitigation when the subject is potentially massive reconfigurations of the Delta.

With so many negative impacts of flooding islands and so many legal and political obstacles, this really doesn’t seem like a strategy worth continued discussion. We’re much more interested in Dr. Robert Pyke’s proposals for reclaiming islands that have already flooded.

In any case, the main issue is not economics. The main issue is political will energized by a vision of a different future for the Delta than the one to which the Center for Watershed Science seems committed

Suddeth’s very thorough analysis is available on the Watershed Science Center website.

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