The Rapanos Supreme Court decision (547 U.S. 715 (2006)) attempted to, but did not, clarify agency regulatory jurisdiction over “navigable waters” under the Clean Water Act. There was no majority court opinion. The plurality opinion was rather narrow in its approach in regulating other than traditional navigable waters under the Clean Water Act, but the concurring opinion by Justice Kennedy has been cited as the guiding principle with his broader “significant nexus” test.

In 2007, the U.S. Army Corps of Engineers (“Corps”) and Environmental Protection Agency (“EPA”) issued a rather confusing guidance, applying the Rapanos decision to Clean Water Act navigable waters, including promulgating a new, very detailed, and time-consuming jurisdictional determination form for agencies to complete in regulating other than traditionally navigable waters under the Clean Water Act.

The December 2, 2008, EPA/Corps revised guidance is only 13 pages long, and it does not clarify much. It does not back off the complexities of the 2007 guidance, their new detailed jurisdictional determination form, or the myriad of details under the “significant nexus” test.

All the new guidance does is attempt to clarify three simple areas.

The first area of clarification is that the agencies will assert jurisdiction over traditionally navigable waters, including historically navigable waters, and wetlands adjacent to those navigable waters on a categorical (not case-by-case) basis. The agencies proceed to re-affirm their broad definition of those adjacent wetlands under the regulations to include wetlands separated from traditionally navigable waters by man-made barriers, such as dikes.

The second clarification is that relatively permanent non-navigable tributaries of traditionally navigable waters and their adjacent wetlands with a continuous surface connection are also regulated on a categorical basis. The agencies reiterate that a non-navigable tributary of those navigable waters is a non-navigable water body whose waters flow into the those navigable waters either directly or indirectly by means of other tributaries. The flow must be relatively permanent, which includes year-round flow (except due to drought) or that have a continuous flow at least seasonally (e.g., three months a year). However, they add that relatively permanent does not include ephemeral streams which flow only in response to rainfall or intermittent streams which do not typically flow year-round.

The first two clarifications are more aligned with the Rapanos plurality opinion. The third clarification is that agencies will use Justice Kennedy’s “significant nexus” test or case-by-case approach only to regulate non-traditional navigable waters, such as certain adjacent wetlands and non-navigable tributaries that are relatively impermanent. The “significant nexus” test includes both hydrologic factors (volume, duration, frequency of flow, size of watershed, average annual rainfall, etc.), and ecological factors (potential of tributaries to carry pollutants to traditional navigable waters, functions as aquatic habitat, potential of wetlands to trap and filter pollutants or store flood waters, etc.). However, swales or erosional features (gullies, small washes, etc.) and ditches, including roadside ditches excavated wholly in and draining in only uplands and which do not carry permanent flow of water, are not jurisdictional waters under the guidance.

Thus, other than reiterating the documentation requirements and very narrowly clarifying only a few points, the Corps/EPA guidance does not really simplify that much, as the complex “significant nexus” test and the burdens both on the regulated community and the regulators in documenting the “significant nexus” test will continue to plague the 404 program, until Congress acts.