Flood Risk Management and the American River Basin An Evaluation (1995) / Chapter Skim
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6 FLOOD RISK MANAGEMENT: IMPLICATIONS FOR THE AMERICAN RIVER AND THE UNITED STATES
6 FLOOD RISK MANAGEMENT: IMPLICATIONS FOR THE AMERICAN RIVER AND THE UNITED STATES
Pages 177-202
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From page 177... ...
recommended flood control dry dam on the American River (USAGE, Sacramento District, 1991) and its request to continue studies of other alternatives to address the flooding problem (P.L.
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From page 178... ...
Because the committee believes that the lessons of the American River can be transferred to other areas of the nation, parallel recommendations for reform of national policy on flood risk management are also offered. THE AMERICAN RIVER FLOOD RISK MANAGEMENT CONTROVERSY: THE KEY ISSUES The Flood Control Act of 1962 (P.L.
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From page 179... ...
100-202) to pay special attention to flood control through a dry dam option (USAGE, Sacramento District,l991J: The conferees .
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From page 180... ...
In the 1994 Alternatives Report, which has reanalyzed the data, the Sacramento District continued to report that substantially reduced flood risk and increased net benefits could be achieved by construction of storage at the Auburn site. Therefore, a question remains: Can an alternative based on existing storage and on the lower American River levees provide an acceptable level of risk reduction for the city?
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From page 181... ...
to replace these benefits at another site (USAGE, Sacramento District, 1991~. If this was the estimation method, then this cost estimate is an upper bound because replacement water supply, for example, might be acquired from water markets at lower costs (Science Applications International, 1991~.
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From page 182... ...
In fact, the new USACE risk analysis procedures were developed to directly address and analyze such uncertainty (see Chapter 4~. The Sacramento District favored the 400-year protection dry dam alternative, SAFCA sought 200-year protection through a dry dam, and others argued that an acceptable level of protection was possible without a dry dam.
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From page 183... ...
THE CHOICE TO BE MADE: ACCEPTABLE REMAINING FLOOD RISK The committee has not identified any national standard for acceptable levels of flood risk reduction, but it understands the intent of current national policy as follows: investment (private or public) in hazardous areas should, to the extent practicable, internalize the costs of choosing such a location by (1)
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From page 184... ...
Costs of flood risk management are the budget outlays for a flood control project, plus any unmitigated environmental damages from the project. Costs also include the foregone value of activities either removed from, or not located in, a flood-prone area.
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From page 185... ...
In the committee's view, the decision of SAFCA to choose a reduced-size flood risk reduction project, as well as decisions to develop Natomas, has been made in the absence of a requirement to bear reasonable responsibility for the remaining flood risk. Instead, there may be an implicit assumption that such costs will be borne by others, either as disaster aid payments or by a significant federal contribution to construction of flood control works.
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From page 186... ...
WATER PROJECT COST SHARING A product of the history of federal involvement in flood control project construction in the American River basin, and the federal provision of flood insurance and disaster aid, is a perception that flood risk management is a federal responsibility. For example, the Natomas development plan is to intensely develop a flood-prone area once an upgraded agricultural levee system is certified by FEMA as providing "100-year protection" under the NFIP.
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From page 187... ...
Because of the complexity, the Sacramento District did not report cost sharing burdens for the different alternatives in the 1994 Alternatives Report. The committee understands the logic behind the original federal financial participation in flood control works widespread benefits and limited ability to pay.
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From page 188... ...
and confuses the traditional and the new approaches to calculating flood risk. Finding an appropriate way to express the concept of flood recurrence interval and the T-year flood is a persistent problem in risk communication.
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The new USACE risk analysis procedures allow the transfer of this framework to flood risk management. This transfer should occur.
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Levee building can provide a good illustration of the kinds of consequences that should be discussed and evaluated in association with a flood risk reduction project. In rivers not bounded by levees, rises in stage usually most affect structures nearest the river, with the effects of overbank flow diminishing with distance from the river.
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Second, the focus only on real property losses may not reflect the different duration of flooding or the rapidity of the rising waters and the threat to evacuation opportunities. Table 6.1 gives several other representations of flood risk that can be used to improve risk communication.
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Therefore, the probability of a relatively catastrophic event within the lifetime of most residents is roughly equal to the probability of flipping a fair coin and getting heads. IMPROVED APPROACHES TO FLOOD RISK MANAGEMENT PLANNING As a result of laws such as the National Environmental Policy Act (NEPA)
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From page 193... ...
Failure by the Sacramento District and SAFCA to initially incorporate a wide range of purposes and institutional adjustments as a part of plan formulation, and to open the planning process to multiple interests, has been a barrier to agreement on a flood risk management alternative for the American River. Federal flood control planning in California in the past decade and a half has been characterized by citizen groups or local governments who are not project sponsors hiring their own consultants to determine what alternatives are technically feasible and to describe the social and environmental impacts mentioned in federal reports more fully.
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From page 194... ...
Failure to expand the planning purposes meant that the Sacramento District could not develop a broad constituency of support, because the plan made flood control a competing purpose against habitat restoration and water supply, rather than developing an integrated package. If multiple purposes had remained the focus of planning, as had been suggested by the original study authorities, alternatives capable of coalition building might have emerged.
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From page 195... ...
The Sacramento District appears to have directed its attention primarily to flood risk reduction and in so doing has motivated opposition to its recommended flood control alternative. This planning approach might be explained by the original authorization language for the study (stressing flood control and a dry dam)
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While these measures fall outside the Sacramento District's view of its implementation authority, the failure to include such measures in plan formulation means that a source of support for any flood risk management alternative is lost. At some point, it may be determined that a desired amount of risk reduction will require a dry dam near the Auburn site.
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From page 197... ...
The first line of flood protection would achieve high levels of flood damage reduction from a modified and reoperated system with Folsom as the key element. What is significant here is that this approach would reduce the likelihood of the dry dam impounding water, and hence the possibility and frequency of environmental impacts occurring in the canyon would be reduced.
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From page 198... ...
Certain recent federal environmental rulings may affect the opportunities to implement some of the flood risk management alternatives for the American River. Oversight and coordination of studies and proposals related to flood control and to other aspects of water management will be required if any alternatives to address the potentially conflicting purposes are to be implemented.
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From page 199... ...
They include water quality standards, limitations on exports from the delta, and assurances that the plan is intended to create conditions in the delta that will avoid the need for any additional listings under the Endangered Species Act during the next 3 years. It will be some time before final decisions are made implementing this proposal and before it will be known how the additional flow, if mandated, will be allocated among the various tributaries.
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From page 200... ...
CONCLUSION Agreements on acceptable level of flood risk and on the alternatives to achieve that level have escaped the American River planning process. If there is to be a resolution of the issue of appropriate flood risk for the American River, alternative planning approaches and new leadership from outside the Sacramento District, while drawing on the resources and expertise housed in USACE and the district, will be needed.
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From page 201... ...
The federal government, working with private insurers, should develop provisions for sharing the cost of flood insurance premiums with communities and individuals who implement structural and nonstructural flood damage reduction measures. · Before authorizing additional federal financial commitments for flood control on the American River, Congress should explicitly determine whether flood control on the American River constitutes a problem warranting federal involvement based on the presence of widespread national benefits or the limited ability of the community to provide for its own flood protection.
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The state needs to increase its participation in, and the resources it dedicates to, the basinwide water resources planning needed to build a consensus on technical and institutional strategies to manage competing water demands, including flood risk management. ~, ~ · For especially contentious disagreements, USACE should advise its Districts to facilitate but not dominate the local decisionmaking process.
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