Congressional leaders will gather in mid-April for hearings on the future of wetlands in America. Much hinges on their ability to generate momentum toward lasting legal protections for these incomparable resources. We have lost more than half of our country's natural wetlands and continue to lose them at a rate of 80,000 acres per year. What's worse, the fabric of our current wetlands protection laws has been worn threadbare.

The passage of the Clean Water Act in 1972, with a provision known as Section 404 that protected wetlands, represented a seminal moment in American conservation history. Section 404 included unprecedented language that allowed us to slow down nationwide draining and filling of wetlands. More than 30 years later, in the wake of multiple poor decisions by the Supreme Court, we find this protection weakened by a steady stream of challenges focusing on certain words in Section 404, namely "navigable," as in, these protections extend to the navigable waters of the United States.

The Supreme Court's most recent decisions came in cases that dealt with whether developers can build on wetlands adjacent to tributaries that flow into larger water bodies. Not navigable in the traditional sense of the word, these wetlands are nevertheless of huge importance. The court's ruling was a three-way-split decision that has made an already confusing regulatory arena even more confusing.

There were no clear winners and losers in the 4-1-4 Supreme Court action, but there's one bit of certainty to be gleaned from this latest scrutiny of the Clean Water Act's wetlands protections: We need decisive new legal wording so that all Americans know exactly what constitutes a wetland in need of protection. For 34 years, we have had a means to protect wetlands, but now when they are even fewer in number and their importance and societal values are far better understood, we must confront the fact that this protection has been left frayed and tattered.

Whether by regulatory changes made by the Bush administration through our federal agencies, or through legislative changes in Congress in the form of a brand new law or modifications to Section 404, our leaders in Washington must enact comprehensive new language that prevents wetlands protection questions from being continually kicked into our courts.

Why is it so important to have strong new legal language to protect wetlands?

Wetlands provide crucial habitat. Almost half of our country's bird species nest or feed in wetlands. One-third of our plant species live in wetlands. More than one-third of our threatened and endangered species live only in wetlands. Coastal wetlands provide habitat, especially as nurseries, for more than 75 percent of fish and shellfish caught commercially and up to 90 percent of fish caught recreationally.

Wetlands give us cleaner water. When water moves into a wetland, it slows down and pollutants settle to the bottom. A wetland and its plants filter out and absorb much of the water's pollutant load before passing it into our streams, rivers, lakes and estuaries. Seventy percent of sedimentary pollutants in runoff can be filtered by a wetland - and up to 92 percent of phosphorus, 95 percent of nitrogen and 90 percent of bacteria. We also have recently learned that wetlands are among the planet's most prolific carbon sinks and improvers of air quality.

Wetlands prevent floods. As water levels rise, wetlands accommodate the rising water, spread and store the influx, and reduce the velocity of downstream flows. A 1-acre wetland can store 1.5 million gallons of floodwater. The horrible blows landed on the chins of Louisiana and Mississippi by Hurricane Katrina would have been much better absorbed had so much of the region's wetlands not already disappeared.

Before the recent cases came to the Supreme Court, the United States was already in need of more effective wetlands protection. Any hopes that the cases would deliver clear new national guidance on how to properly stem wetlands loss have been dashed.

As we begin repeating yet another cycle of arguing over Section 404 in our courts, our elected leaders must realize that, in the meantime, wetlands losses are continuing unabated,and action is needed. More than three decades after the establishment of wetlands protections in the Clean Water Act, it is time to put binding new language in place that draws bright shining lines around a national resource now more in need of protection than ever.

In the coming congressional hearings, our leaders have a chance to start doing exactly that.

(Mullins, who works in Washington, D.C., is the wetlands and farm policy initiative manager for the Theodore Roosevelt Conservation Partnership. He is helping organize a summit on wetlands issues April 11-13 in Minneapolis. - Editor)