33 C.F.R. § 234.7 – Evaluation framework.

(a) General. To inform the overall decision-making process, this section describes the common framework and general requirements to be used by the Corps in evaluating and ensuring full consideration of the social, environmental, and economic benefits and costs to society of any separable elements and potential alternatives for Federal investment. This will include their performance with respect to the Guiding Principles and their contributions to the Federal Objective. Any key assumptions that affect the analysis of alternatives shall be clearly described in the study.
(b) Economic, environmental, and social effects.
1. (1) The Corps' analytical framework for evaluating Federal investments should focus on the key economic, environmental, and social effects that are relevant to the investment decision. Typical NEPA analyses emphasize environmental effects and benefits, including ecosystem services, and these should also be used as a core part of water resources alternatives analysis. A benefit-cost analysis would be conducted for each alternative. Ecosystem services are an important benefit-cost category that should be included in the benefit-cost analysis.
2. (2) In addition, the scale of the analysis can be adjusted for a given study. While all analyses should share common elements, how these elements are achieved can depend on the identified problem or opportunity. It is important to establish a consistent analytic approach for each study. When implementing its ASPs, the Corps will consider and, where it deems appropriate, align with the latest Federal methods and guidance (for example, updated OMB Circulars and applicable interagency guidance) to ensure that the analytical framework accounts for all significant economic, environmental, and social costs and benefits, including ecosystem services. Where possible, monetization enables the incorporation of the values placed on the benefits and costs evaluated and provides a way to evaluate trade-offs in common analytical units (dollars). OMB Circulars A-4 and A-94 provide guidance on appropriate use of monetization methods. The Corps anticipates that it will not be possible to monetize all social and environmental costs and benefits of the alternatives. In these cases, the Corps should quantify the social and environmental costs and benefits and when neither monetization nor quantification is possible, the Corps should qualitatively describe the social and environmental costs and benefits in sufficient detail to allow differentiation across alternatives. Relevant monetary, quantitative, and descriptive information will be fully assessed and considered in the analysis.
(c) Best available actionable science and commensurate level of detail.
1. (1) Analysis to support the evaluation of alternatives shall use the best available actionable science, to include Indigenous Knowledge, data, analytical techniques, procedures, models, and tools in ecology, hydrology, economics, engineering, biology, and other disciplines to the extent that sufficient funding is available, and to the extent such information is relevant and appropriate to the subject investment. To the extent feasible, the effects of the alternatives should be monetized. Effects will be monetized, quantified, or described, in that order.
2. (2) The level of detail required to support alternatives analysis may vary but should be sufficient to inform the decision-making process efficiently and effectively. The level of detail, scope, and complexity of analyses should be commensurate with the scale, impacts, costs, scientific complexities, uncertainties, risk, and other aspects (such as public concern) inherent in potential decisions.
(d) Risk and uncertainty. When analyzing potential Federal water resources investments, the Corps shall identify, describe, and quantify (if feasible) areas of risk and uncertainty and consider them in decision-making. Risks and uncertainties shall be identified and described in a manner that is clear and understandable to the public and decision-makers. This includes describing the nature, likelihood, and magnitude of risks, as well as the uncertainties associated with key supporting data, projections, and evaluations of competing alternatives. Risk and uncertainty are inherent in economic analyses as well as the analysis of physical and biological factors, no matter the technique or methodology employed. The study should estimate the extent to which the outcomes from an investment may vary over time from the estimates provided in the study, both in the short-term and in the less predictable future, due to uncertainty. Knowledge of risk and uncertainty and the degree of reliability of the estimated consequences will better inform decision-making. When there are considerable uncertainties concerning the ability of an alternative to function as desired (such as producing the desired outputs and/or the general acceptability of the alternative) the option of pursuing improved data or models should be considered. Reducing risk and uncertainty may involve increased costs or loss of benefits. The advantages and costs of reducing risk and uncertainty should be explicitly considered in formulating alternatives and the overall decision-making process.
(e) Adaptive management. Adaptive management measures shall be clearly identified and evaluated as part of alternatives to the extent that such measures are commensurate with the significance of the proposed activity and available resources. Adaptive management measures are particularly useful when making management choices in the face of uncertainty, such as when detailed information and tools are not readily available.
(f) Climate change. Conditions resulting from a changing climate shall be identified and accounted for in all stages of the planning process, and uncertainties associated with climate change will be identified and described. Analysis of climate change impacts shall reflect the best available actionable science and will leverage region-specific information from Federal, Tribal, State, local, and non-governmental partners. The Corps shall incorporate a climate-informed science approach considering impacts such as inland and coastal climate change impacts on flood and drought hazards using the most up-to-date science, policies, and tools available. The Corps shall also ensure climate resilience and adaptation are incorporated and considered throughout the planning process and across alternatives, including a discussion on how climate, drought, and ecosystem resilience may intersect for that particular action and can contribute to the economic vitality and water resources resilience of the Nation. The changing climate should inform the understanding of water resources needs and how those needs can potentially be addressed.
(g) Water availability, water uses, and resilience. The consideration of multiple uses, competing demands, and the potential future uses of the water resources shall be taken into account when formulating and evaluating solutions to a water resources problem or challenge. Water availability and efficient use of water shall be considered in designing the alternatives, as shall resilience, when applicable to the purpose of the study. The analysis shall consider water availability, water uses, and resilience over a range of conditions, from too little water in drought and multiple-use scenarios, to too much water in flood scenarios.
(h) Nonstructural and nature-based solutions. Nonstructural measures alter the use of existing infrastructure or human activities to generally improve, avoid, or minimize adverse changes to existing hydrologic, geomorphic, and ecological processes. Nonstructural measures may be combined with fewer or smaller traditional structural project components to produce a complete alternative plan or may be used instead of a structural project. In the development of alternatives, the use of natural systems, ecosystem processes, and nature-based solutions shall be considered. Full consideration and reporting on nonstructural and nature-based alternative actions shall be an integral part of the evaluation of Federal water resources investment alternatives, and a full nonstructural in addition to a full nature-based alternative will be included in the final array of alternatives. Nonstructural and nature-based aspects should also be included in the other alternatives in the final array when appropriate.
(i) Tribal treaty rights. Each of the alternatives considered for a water resources investment must be consistent with the protection of Tribal treaty rights. Alternatives that impact Tribal treaty and water rights should be screened out as soon as the Corps becomes aware of such impacts, and the study will document why the alternatives have been screened.
(j) State water law. Alternatives for water resources investments must be consistent with applicable State laws, including water rights and decrees, to the extent that these do not conflict with Federal laws and regulations. Analyses should identify legal constraints that preclude selection of an otherwise viable alternative.
(k) International obligations. Alternatives for water resources investments must be consistent with meeting treaty and other international obligations. Analyses should identify international obligations that preclude selection of an otherwise viable alternative.
(l) Period of analysis. The period of analysis for the study shall be documented with an appropriate justification, and used to evaluate each alternative.