2008. “Levee Decisions and Sustainability for the Sacramento-San Joaquin Delta
The Sacramento-San Joaquin Delta’s fragile levees are subject to several physical realities that make them increasingly prone to failure. State planners face the challenge of preparing for future Delta flooding. This study presents an economic method for approaching the evaluation of Delta island le...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.613.729 http://deltasolutions.ucdavis.edu/pdf/WorkingPapers/LeveeDecisions-2009Draft.pdf |
| Summary: | The Sacramento-San Joaquin Delta’s fragile levees are subject to several physical realities that make them increasingly prone to failure. State planners face the challenge of preparing for future Delta flooding. This study presents an economic method for approaching the evaluation of Delta island levee upgrades and repairs. A Levee Decision Analysis Model (LDAM) is applied to the question: How should the state economically prioritize levee upgrade and repair efforts in the Delta? We focus on 34 major agricultural islands that make up most of the Delta’s Primary Zone and include all non-urban subsided islands. This initial analysis indicates that it is economically optimal to not upgrade all 34 Delta islands examined, mostly because levee upgrades are expensive, but produce little improvement in levee reliability. When we assume increased effectiveness of upgrades, it becomes optimal to upgrade some islands. Other islands are never optimally upgraded, even under the most optimistic scenario. Our analysis also suggests that from an economic perspective, taking into account land and asset values, it is not cost effective to repair between 18 and 23 of these islands when they fail. When property values for all islands were doubled in a sensitivity analysis, only four islands of those originally not repaired become cost effective to repair. The LDAM model presented here is a useful approach for Delta policy-makers. It provides a quantitative framework for addressing several relevant questions regarding reasonable levee upgrade and repair investments. These initial results may act as a springboard for discussion, and the LDAM model as a working framework for developing an optimal strategy. An important and inescapable conclusion of this analysis is that maintaining the current Delta landscape is unlikely to be economical from a business or land use perspective. 1 |
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