BELTSVILLE - Thousands of miles of Maryland's freshwater streams are a mess, overloaded with nutrients, stripped of wildlife habitat and forest buffers, and crossed with barriers to fish migration.
The state Department of Natural Resources and the U.S. Environmental Protection Agency issued yesterday the first comprehensive study of small and medium-size streams. It found that almost half of the state's nearly 9,000 miles of streams are in poor health and that the rest show serious signs of stress.
The biggest problems are development that has destroyed forests and farm fields, and man-made changes to stream channels that increase storm runoff. The report warned that more Maryland streams "will likely degrade in the years to come" if sprawling development "continues to consume our forests and farmlands as it has in the past."
The survey sampled fish, aquatic invertebrates, reptiles, amphibians and chemicals at 1,000 randomly selected sites from Garrett County to the coastal bays between 1995 and 1997. Ten percent of the streams were considered healthy, while about half were found to be unhealthy.
"These streams are on the pivotal cusp, and what we must do is make sure those that are on the edge don't go over," DNR Secretary Sarah Taylor-Rogers said at a news conference at Little Paint Branch Park.
"We have to make sure the ones that are healthy stay that way and the ones that are unhealthy improve."
The study, one of a series of assessments of forests, streams, estuaries and land-use policies throughout the mid-Atlantic states, is a "call to action for the citizens of Maryland," said Norine E. Noonan, assistant administrator for research and development for EPA.
It provides a "clear indication of what we need to accomplish over the next 10 years," said Taylor-Rogers, who said paved areas and other surfaces impervious to water were the greatest threat to the health of waterways.
Roads, parking lots, driveways and sidewalks create funnels that pump torrents of silt and chemical-laden runoff into creeks and rivers, eroding channels and banks, and destroying food supplies and habitat.
The survey found that brook trout disappear from a stream when as little as 2 percent of the land nearby is paved over, that the health of the stream declines greatly when more than 15 percent of the land in a stream's watershed is developed, and that only the hardiest of reptiles and amphibians can survive in streams where 25 percent of the land is developed.
Researchers also found that almost 1,500 miles of meandering freshwater streams have been straightened or channeled, their banks lined with concrete or riprap in urban areas, or stripped of vegetation as they flowed through crop fields.
The three worst streams for aquatic life are in Anne Arundel County: Marley Creek in the industrial northern part of the county, and Muddy Creek and a tributary to Smith Creek, both in the West River watershed in the rural southern part of the county.
The healthiest streams were Reeder Run in Charles County, Little Laurel Run in Garrett County and a tributary to the Little Conococheague Creek in Washington County.
In most cases, streams with the most vegetation on their banks were in the best shape.
Maryland and the EPA shared the cost of the $2.5 million study.