The EPA is pushing a new rule called the Waters of the United States which would expand the definition of a navigable water to include almost any water feature on a property including ditches that are dry the vast majority of the year. If this rule goes into effect the federal government has in effect nationalized/taken control of all water in the United State (and in many cases the land that borders the water).
These waters are usually under the jurisdiction of the states. No surprise that various groupings of states challenged the EPA in court. The first of the articles on this subject discusses the only lawsuit that successfully put a stop to the implementation of the rule, at least until further studies are conducted. To read more about which group of states was successful, click on this link.
The second article discusses whether the states that were unsuccessful in their challenge of the Waters of the United States rule, will be protected from, or obligated to abide by, the rule. To learn more click on this link.