“ Constricting § 27 to encompass only laws relating to proprietary rights, and thus leaving the permit requirements at issue to the federal sphere, accomplished that goal. The Court's discussion immediately after its extended discussion of § 27 illustrates the relation between the sections. Before distinguishing § 27's role in saving state law from § 9 (b) 's role in the sphere of exclusive federal regulation, the Court concluded:
" [Section 27] is therefore thoroughly consistent with the integration rather than the duplication of federal and state jurisdictions under the Federal Power Act. ”

“ As petitioner argues, California's minimum stream flow requirement might plausibly be thought to "relat [e] to the control, appropriation, use, or distribution of water used . . . for . . . other uses," namely the generation of power or the protection of fish. This interpretation would accord with the "presumption against finding pre-emption of state law in areas traditionally regulated by the States" and " 'with the assumption that the historic police powers of the States were not to be superseded by the Federal Act unless that was the clear and manifest purpose of Congress.' " California v. ”

“ See Square D Co., supra, at 424, 106 S.Ct., at 1930 (for statutory determinations, " 'it is more important that the applicable rule of law be settled than that it be settled right. . . . This is commonly true, even where the error is a matter of serious concern, provided correction can be had by legislation,' " quoting Burnet v. Coronado Oil & Gas Co., 285 U.S. 393, 406, 52 S.Ct. 443, 447, 76 L.Ed. 815 (1932) (Brandeis, J., dissenting) ) . ”

“ As Congress directed in FPA § 10 (a) , FERC set the conditions of the license, including the minimum stream flow, after considering which requirements would best protect wildlife and ensure that the project would be economically feasible, and thus further power development. ”