Disappearing mussel species and threatened water quality from development have prompted advocates to push for increased protections for Ohio's Big and Little Darby Creeks.

The Environmental Protection Agency's Outstanding National Resource Waters classification is the highest level of protection under the Clean Water Act for waterways with exceptional recreational or ecological significance.

Chris Tavenor, associate general counsel with the Ohio Environmental Council, said the deadline to submit public comments on the Ohio Environmental Protection Agency's review of the Darby Creeks is January 31.

"Ohio currently has no rivers, lakes or streams that received this level of protection," said Tavenor. "Essentially, the designation would significantly limit all future new point source pollution into the streams."

Submit comments online at 'theoec.org.'

Forty-one species of freshwater mussels live in Darby Creek waters - eight of which are on Ohio's endangered list, according to the state Department of Natural Resources.

The Pew Charitable Trusts says the federal government has been slow to use the special designation, despite mounting evidence of worsening pollution in the nation's freshwaters.

Environmental groups recently appealed the approval of a new wastewater permit that would double the amount of polluting discharge the Plain City water treatment plant is allowed to release into Big Darby Creek.

Tavenor said the "outstanding" designation would likely block any future discharge permits.

"It wouldn't change how things have been permitted in the past," said Tavenor, "but it would limit and change how any future permits would go on and make it very, very difficult for any new point sources to be created."

According to an Environmental Integrity Project Report published last year, 51% of assessed river and stream miles across the nation - around 700,000 miles of waterways - are polluted.

This story was produced in association with Media in the Public Interest and funded in part by the George Gund Foundation.

City water leaders in Des Moines are considering a $50 million plan to use Mother Nature as a giant water filter to remove nitrates from the city's drinking water.

While they occur naturally, nitrates can be hazardous if consumed in large amounts. They have posed health problems in the Midwest for decades, partly the result of fertilizer and manure runoff into groundwater, which eventually makes it into tap water.

Ted Corrigan, CEO and general manager of Des Moines Water Works, said they are considering a process thousands of years old to remove nitrates, by drilling radial collector wells into the bedrock near the Des Moines River, and then allowing the ground to do the work.

"The time that it takes for the water to move through the ground helps clean it up a little," Corrigan explained. "It's literally filtered through 30, 40, 50 feet of sand."

He pointed out the radial collector wells would be an addition to the current mechanical methods Des Moines already uses to remove nitrates, which cost about $10,000 a day every time they run. The wells can filter about 25 million gallons of water a day.

The city relies on the Des Moines River for most of its drinking water, but its nitrate levels spike in the winter. Corrigan noted water in the collector wells could also be stored for use when the river water exceeds safe drinking standards. He added the stored water would also help meet the demands of a growing population.

"You know, we keep kind of chasing this problem," Corrigan observed. "As we grow, we put more tools in the toolbox. Radial collector wells are kind of another tool that we can use to source low-nitrate water. It's another option for us to implement, to meet growing demands and maintain water quality."

He emphasized Des Moines awaits a report from the U.S. Geological Survey this spring before digging its wells.

While Connecticut elected officials want to import hydroelectric power from Canada, one group said the option would not be as environmentally conscious as it might seem.

Hydropower turbines are known for injuring or killing the migrating fish passing through them. Environmental advocates feel other considerations must be made, especially as the U.S. moves further on the path toward renewable energy.

Rhea Drozdenko, the Connecticut River Conservancy's river steward in Connecticut, noted some of the dam operators do make adaptations for fish populations, but they could be doing more.

"There are things like fish ladders that help those migratory fish get from the river to the reservoir above," Drozdenko acknowledged. "But a lot of those fish ladders were made, like, 20 years ago, and they aren't actually as effective as promised."

She added updating the fish ladders would be an option. As Connecticut residents face rising power prices, Drozdenko said her organization sees importing hydropower as a temporary solution, with costs going beyond a customer's electric bill. They would also rather see local solutions instead of the state outsourcing its power needs.

Despite the advances in technology, including different types of turbines to generate power, hydroelectric dams also affect river health, and other plant and wildlife species.

Kathy Urffer, the Connecticut River Conservancy's river steward in Vermont, thinks improvements can be made, but it is important to look at all the effects of all the options for energy sources.

"When you start to look at each potential source of energy -- there's wind, there's solar, there's hydro, there's coal -- each one of them has impacts in different ways," Urffer explained. "And different intensity of impacts, even in terms of the sizing of each facility or where it is placed. "

She added there could be easier ways to add renewable energy to the mix in Connecticut with few downsides for the environment. The state already has 13 dams producing electricity.

The State Water Board now says it will take another two years to finalize the San Francisco-San Joaquin Delta water management plan, and it is proceeding with voluntary agreements with water agencies in the meantime.

Conservation groups spoke out at a workshop held by the board late last week - and some are asking the board to scrap the voluntary agreements.

Ashley Overhouse - California water policy advisor with Defenders of Wildlife - said a new plan to put more water into the estuary is crucial since four species of native fish have made the federal endangered species list since 1992, bringing the total to 6.

"At this point, we're trying to avoid extinction for most native fish populations that rely on the Bay-Delta," said Overhouse. "We're talking about not just delta smelt, we're talking about all runs of salmon, longfin smelt, and sturgeon. They would be completely wiped out."

Over-pumping of freshwater, pollution and climate change contribute to poor water quality. Multiple water agencies pump water from the delta and send it to the farms of the Central Valley and to cities in Southern California.

Other agencies are resisting entreaties to release more water into the delta. The group representing public water agencies, the State Water Contractors, spoke out in favor of the board's decision to move forward with the voluntary agreements.

Overhouse said the whole process has dragged on far too long.

"One of the reasons why this has been held up is due to political reasons," said Overhouse. "Water agencies have delayed the planning process significantly in order to negotiate the amount of water that they would have to release."

The water board is taking public comment on the report that establishes the scientific basis for the voluntary agreements, now through February 8.

The Bay-Delta plan is supposed to be updated every three years but the last major update took place in 1995.