WOUS TNWs Attachment 

Waters that Qualify as Waters of the United States 

Under Section (a)(1) of the Agencies’ Regulations 

The Environmental Protection Agency (EPA) and United States Army Corps of 

Engineers (Corps) “Guidance on Identifying Waters Protected by the Clean Water Act” guidance 

(Guidance) affirms that EPA and the Corps will continue to assert jurisdiction over “[a]ll waters 

which are currently used, or were used in the past, or may be susceptible to use in interstate or 

foreign commerce, including all waters which are subject to the ebb and flow of the tide.” 33 

C.F.R. § 328.3(a)(1); 40 C.F.R. § 230.3(s)(1). The Guidance also states that, for purposes of the 

guidance, these “(a)(1)waters” are the “traditional navigable waters.” These (a)(1) waters include 

all of the “navigable waters of the United States,” defined in 33 C.F.R. Part 329 and by 

numerous decisions of the federal courts, plus all other waters that are navigable-in-fact (e.g., the 

Great Salt Lake, UT and Lake Minnetonka, MN). 

EPA and the Corps are providing this guidance on determining whether a water is a 

“traditional navigable water” for purposes of the Guidance, the Clean Water Act (CWA), and the 

agencies’ CWA implementing regulations. This guidance is not intended to be used for any other 

purpose. To determine whether a water body constitutes an (a)(1) water under the regulations, 

relevant considerations include Corps regulations, prior determinations by the Corps and by the 

federal courts, and case law. Corps districts and EPA regions should determine whether a 

particular waterbody is a traditional navigable water based on application of those considerations 

to the specific facts in each case. 

As noted above, the (a)(1) waters include, but are not limited to, the “navigable waters of 

the United States.” A water body qualifies as a “navigable water of the United States” if it meets 

any of the tests set forth in 33 C.F.R. Part 329 (e.g., the water body is (a) subject to the ebb and 

flow of the tide, and/or (b) the water body is presently used, or has been used in the past, or may 

be susceptible for use (with or without reasonable improvements) to transport interstate or 

foreign commerce). The Corps districts have made determinations in the past regarding whether 

particular water bodies qualify as “navigable waters of the United States” for purposes of 

asserting jurisdiction under Sections 9 and 10 of the Rivers and Harbors Act of 1899 (33 USC 

Sections 401 and 403). Pursuant to 33 C.F.R. § 329.16, the Corps should maintain lists of final 

determinations of navigability for purposes of Corps jurisdiction under the Rivers and Harbors 

Act of 1899. While absence from the list should not be taken as an indication that the water is not 

navigable (329.16(b)), Corps districts and EPA regions should rely on any final Corps 

determination that a water body is a navigable water of the United States. 

If the federal courts have determined that a water body is navigable-in-fact under federal 

law for any purpose, that water body qualifies as a “traditional navigable water” subject to CWA 

jurisdiction under 33 C.F.R. § 328.3(a)(1) and 40 C.F.R. § 230.3(s)(1). Corps districts and EPA 

regions should be guided by the relevant opinions of the federal courts in determining whether 

waterbodies are “currently used, or were used in the past, or may be susceptible to use in 

interstate or foreign commerce” (33 C.F.R. § 328.3(a)(1); 40 C.F.R. § 230.3(s)(1)) or “navigablein-fact.” 
2

This definition of “navigable-in-fact” comes from a long line of cases originating with 

The Daniel Ball, 77 U.S. 557 (1870). The Supreme Court stated: 

Those rivers must be regarded as public navigable rivers in law which are 

navigable in fact. And they are navigable in fact when they are used, or are 

susceptible of being used, in their ordinary condition, as highways for commerce, 

over which trade and travel are or may be conducted in the customary modes of 

trade and travel on water. 

The Daniel Ball, 77 U.S. at 563. 

In The Montello, the Supreme Court clarified that “customary modes of trade and travel 

on water” encompasses more than just navigation by larger vessels: 

The capability of use by the public for purposes of transportation and commerce 

affords the true criterion of the navigability of a river, rather than the extent and 

manner of that use. If it be capable in its natural state of being used for purposes 

of commerce, no matter in what mode the commerce may be conducted, it is 

navigable in fact, and becomes in law a public river or highway. 

The Montello, 87 U.S. 430, 441-42 (1874). In that case, the Court held that early fur trading 

using canoes sufficiently showed that the Fox River was a navigable water of the United States. 

The Court was careful to note that the bare fact of a water’s capacity for navigation alone is not 

sufficient; that capacity must be indicative of the water’s being “generally and commonly useful 

to some purpose of trade or agriculture.” Id. at 442. 

In Economy Light & Power, the Supreme Court held that a waterway need not be 

continuously navigable; it is navigable even if it has “occasional natural obstructions or 

portages” and even if it is not navigable “at all seasons . . . or at all stages of the water.” 

Economy Light & Power Co. v. U.S., 256 U.S. 113, 122 (1921). 

In United States v. Holt State Bank, 270 U.S. 49 (1926), the Supreme Court summarized 

the law on navigability as of 1926 as follows: 

The rule long since approved by this court in applying the Constitution and laws 

of the United States is that streams or lakes which are navigable in fact must be 

regarded as navigable in law; that they are navigable in fact when they are used, 

or are susceptible of being used, in their natural and ordinary condition, as 

highways for commerce, over which trade and travel are or may be conducted in 

the customary modes of trade and travel on water; and further that navigability 

does not depend on the particular mode in which such use is or may be had -

whether by steamboats, sailing vessels or flatboats- nor on an absence of 

occasional difficulties in navigation, but on the fact, if it be a fact, that the stream 

in its natural and ordinary condition affords a channel for useful commerce. 

Holt State Bank, 270 U.S. at 56. 

In U. S. v. Utah, 283 U.S. 64 (1931) and U.S. v. Appalachian Elec. Power Co, 311 U.S. 
3

377 (1940), the Supreme Court held that so long as a water is susceptible to use as a highway of 

commerce, it is navigable-in-fact, even if the water has never been used for any commercial 

purpose. U.S. v. Utah, at 81-83 (“The question of that susceptibility in the ordinary condition of 

the rivers, rather than of the mere manner or extent of actual use, is the crucial question.”); U.S. 

v. Appalachian Elec. Power Co., 311 U.S. 377, 416 (1940) (“Nor is lack of commercial traffic a 

bar to a conclusion of navigability where personal or private use by boats demonstrates the 

availability of the stream for the simpler types of commercial navigation.”). 

In 1971, in Utah v. United States, 403 U.S. 9 (1971), the Supreme Court held that the 

Great Salt Lake, an intrastate water body, was navigable under federal law even though it “is not 

part of a navigable interstate or international commercial highway.” Id. at 10. In doing so, the 

Supreme Court stated that the fact that the Lake was used for hauling of animals by ranchers 

rather than for the transportation of “water-borne freight” was an “irrelevant detail.” Id. at 11. 

“The lake was used as a highway and that is the gist of the federal test.” Ibid.

1

In summary, when determining whether a water body qualifies as a “traditional navigable 

water” (i.e., an (a)(1) water), relevant considerations include whether a Corps District has 

determined that the water body is a navigable water of the United States pursuant to 33 C.F.R § 

329.14, or the water body qualifies as a navigable water of the United States under any of the 

tests set forth in 33 C.F.R. § 329, or a federal court has determined that the water body is 

navigable-in-fact under federal law for any purpose, or the water body is “navigable-in-fact” 

under the standards that have been used by the federal courts. 

                                        

1 Also of note are two decisions from

                

 the courts of appeals. In FPL Energy Marine 

Hydro, a case involving the Federal Power Act, the D.C. Circuit reiterated the fact that “actual 

use is not necessary for a navigability determination” and repeated earlier Supreme Court 

holdings that navigability and capacity of a water to carry commerce could be shown through 

“physical characteristics and experimentation.” FPL Energy Marine Hydro LLC v. FERC, 287 

F.3d 1151, 1157 (D.C. Cir. 2002). In that case, the D.C. Circuit upheld a FERC navigability 

determination that was based upon three experimental canoe trips taken specifically to 

demonstrate the river’s navigability. Id. at 1158-59. 

The 9th Circuit has also implemented the Supreme Court’s holding that a water need only 

be susceptible to being used for waterborne commerce to be navigable-in-fact. Alaska v. Ahtna, 

Inc., 891 F.2d 1404 (9th Cir. 1989). In Ahtna, the 9th Circuit held that current use of an Alaskan 

river for commercial recreational boating is sufficient evidence of the water’s capacity to carry 

waterborne commerce at the time that Alaska became a state. Id. at 1405. It was found to be 

irrelevant whether or not the river was actually being navigated or being used for commerce at 

the time, because current navigation showed that the river always had the capacity to support 

such navigation. Id. at 1404.