Opinion ID: 785093
Heading Depth: 3
Heading Rank: 4

Heading: Proportional flow requirements

Text: 60 UWAG contends that the proportional flow limitations of the Rule are not supported by the record. 61 The Rule forbids an intake structure from withdrawing more than 5 percent of the annual flow of a river or stream, more than 1 percent of the volume of water within one tidal excursion of an intake located in an estuary or tidal river, or so much water that it disturbs the natural thermal stratification 33 of a lake or reservoir (unless such disruption is beneficial). See 40 C.F.R. § 125.84(b)(3), (c)(2), (d)(2). UWAG contends that these limits are redundant (given the capacity limits), rest on an unsupported assumption (that withdrawing a certain percentage of water means withdrawing an equivalent percentage of larvae and eggs), are arbitrary (as there is no basis for choosing 1 or 5 percent, instead of, say, .5 or 6 percent), effectively zone out lakes and reservoirs from the available waterbodies (because any withdrawal of water necessarily disrupts, at least to some extent, natural thermal stratification), are not technologically or logistically feasible, and were chosen without appropriate regard for their cost. 62 We do not think the EPA acted arbitrarily or capriciously. See Final Rule, 66 Fed.Reg. at 65,276-77, 65,281, 65,301 (justifying the provision). Absolute capacity limits do not protect smaller waterbodies from the deleterious effects of disproportionate withdrawals. Withdrawing too large a volume of water might ... change the physical character of the affected reach of the river and availability of suitable habitat, id. at 65,277 col. 2, and disrupting the natural thermal stratification also affects the balance of nutrients and oxygen, which, in turn, can affect fish migration and spawning, id.; Public Comment & Response No. 068.078 at 1310-11. Because the number of entrained organisms is closely linked to the amount of water passing through the intake structure, it was reasonable for the EPA to use the percentage of water as a rough proxy for the percentage of organisms entrained. Final Rule, 66 Fed.Reg. at 65,277 col. 2. The 5 and 1 percent figures were chosen based on the EPA's conclusion that they are overwhelmingly achievable for new facilities, which have the ability to choose their locations: 34 90 percent of existing facilities in rivers and streams, 92 percent of existing facilities in estuaries or tidal rivers, and most facilities in lakes and reservoirs already meet the relevant requirements. Id. The EPA specifically considered cost and found that the means to comply with those limits are economically practicable for the industry as a whole, Public Comment & Response No. 068.076 at 1305, and UWAG has offered nothing but speculation to the contrary. The EPA recognizes that choosing the precise limits (1 percent, 5 percent, 1 tidal excursion) involves a matter of judgment, but we see no reason to supplant the industry's judgment for the EPA's or to remand a logical aspect of the Rule merely because it involves an element of educated guessing.