On May 27, 2015, after many years of regulatory uncertainty, the U.S. Environmental Protection Agency ("EPA") and the U.S. Army Corps ("Corps") released a final rule defining the scope of "Waters of the United States" under the Clean Water Act. The Rule aims to "clarify" the reach of the federal government's authority under the Clean Water Act, including every section and program under the Act. Its implications are far reaching to industry, home builders, farmers, ranchers, and other landowners.

EPA and the Corps received over 1 million comments in this highly controversial rulemaking, and Congress is debating whether to require the agencies to withdraw the Rule entirely. The most controversial elements of the Rule involve the government's authority to regulate ditches, ephemeral and intermittent streams, dry arroyos in the arid West, and geographically isolated wetlands. Opponents of the rule argue that the Rule is unconstitutional and exceeds the agencies' authority granted by Congress in 1972 when the Act was passed. Others raise concerns that EPA and the Corps failed to adequately consult with states, leading to a flawed policy. A total of 34 states opposed the Rule and 22 asked that the rule be withdrawn.

This Rule is the agencies' response to two Supreme Court cases. In 2001, the Supreme Court in Solid Waste Agency of Northern Cook County (SWANCC) v. Army Corps of Engineers struck down "migratory bird rule," which would have given the agencies the authority to assert jurisdiction over any isolated water used or potentially used by migratory birds. Then, in 2006, the Supreme Court ruling in Rapanos v. United States rejected the agencies' broad interpretation of CWA authority with respect to wetlands and ditches. In that muddled decision, one Justice established a "significant nexus" test for establishing jurisdiction, which provides the agencies foundation for the final rule. Following the Rapanos decision, the agencies have been operating under guidance and working toward the development of a formal rule.

The Rule includes significant changes from the proposal, intended to address many of the criticisms received during the public comment period. The Rule now contains eight categories of jurisdictional waters (as opposed to seven included in the proposal). The Rule makes certain waters, such as tributaries to traditional navigable waters and waters adjacent to those tributaries, categorically jurisdictional. For adjacent waters, the Rule distinguishes between jurisdictional floodplain and non-floodplain waters and includes lateral limits of 1,500 and 100 feet, respectively, from the ordinary high water mark of the nearest traditional navigable water or tributary. Other water bodies must undergo the significant nexus analysis to determine whether such waters have a significant physical, biological, or chemical connection to downstream jurisdictional waters. The rule also specifically protects Prairie Potholes, Western vernal pools, Pocosins, Carolina Delmarva Bays and Texas coastal prairie wetlands, which are deemed similarly situated and must be aggregated to determine whether cumulatively they have a significant impact on downstream water quality.

Importantly, the EPA and Corps for the first time created a bright line between federal and state waters by imposing a 4,000 foot lateral limit on all other waters that do not fall within any of the other categories of jurisdictional waters. Although this is the first time the agencies have drawn such a line, its significance will depend largely upon how broadly the definition of tributary is construed and implemented in the field. A more expansive interpretation of tributary and ditches will increase the locations and numbers of waters still captured by this 4,000 foot limit.

A number of legal challenges are expected, and Congress continues to threaten enactment of new legislation that will overturn the Rule. President Obama has threatened to veto any bill overturning the Rule. In the meantime, the Rule will become effective 60 days after it is published in the Federal Register. Jurisdictional determinations issued after publication of the Rule in the Federal Register can be expected to be made consistent with the Rule.

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