Building on the successful completion of the Still River Greenway in Danbury, the Still River Alliance is taking on new environmental challenges in the 71-square-mile Still River watershed.

That watershed includes tracts in New Milford, Danbury, Brookfield, Bethel, Newtown, New Fairfield and Ridgefield.

The alliance invites the public to attend upcoming events to learn more about it.

The events include the annual Still River Cleanup in Brookfield May 14 and the Danbury Still River Greenway Day, which will be held June 4 along with National Trails Day and Danbury's Walk for Health event.

The 23-mile Still River was polluted for many years by industrial and sewage discharges which took their toll on aquatic life.

The river has improved since Danbury's sewage treatment plant was upgraded in 1993.

State Department of Environmental Protection surveys taken in 1997 and 1998 showed a diversity of finfish, and visitors have reported seeing blue heron, red-tailed hawk and Canada geese along the river corridor.

The river remains on the list of impaired state waters and concerns remain regarding high E. coli levels and potential presence of toxins in areas earlier used for industry.

Recent flooding highlighted the need for improvements to storm water management. High nutrient levels are also responsible for algae growth downstream in Lake Lillinonah.

The alliance has organized a steering committee to explore these concerns, to help the Natural Resource Conservation Service expand the existing river trail to the lower river and to establish related community access in New Milford.

Meghan Ruta, water protection manager of the Housatonic Valley Association, is chairman.

"A 20 percent increase in development since 1985 increases the need for safe, community-based outdoor recreation opportunities," Ms. Ruta said.

"Restoration and promotion of the Still River is a key to meeting this need," she said.

For more information or to volunteer, e-mail stillriveralliance@gmail.com of visit the Still River Alliance on Facebook.