Colonial Lake could soon get much cleaner.

About Colonial Lake

The man-made lake’s origins date to Colonial-era times when Charleston’s boundaries were expanding toward the Ashley River and it was decreed the city could claim the vacant marsh “for use as a common for Charlestown.”Filling marsh was a regular habit at the time and a “common” would be a site for relaxation and gathering. The pond at the site became a focal point of shallow fishing, swimming and boating.Initially called the Rutledge Street Pond, in 1881 the site became formally known as Colonial Lake, in honor of the Colonial Commons that dates to 1768, which created the space for perpetual public use. In the 1880s, the lake was permanently enclosed by squared seawalls. Benches, lighting, tennis courts and other features were added over the decades.Today the lake area measures about 9.5 acres.

And eventually, much greener, too.

City of Charleston officials are working to improve the water quality of the man-made neighborhood lake downtown so that it’s close to or equal to that of the nearby Ashley River.

It’s just part of a planned $4 million makeover that eventually will include re-doing the seawalls and walking paths, adding flower beds and planting more than 90 trees to create more shade and canopy-type coverage.

The water quality improvement is one of the first issues to be addressed. It will be done by adding a new flow line to a storm drain at Beaufain Street that, when combined with the current street level flow valve on Ashley Avenue, will allow greater two-way water movement in and out of the lake.

“It’s so we could have a little more circulation,” Dustin Clemens, Charleston’s assistant director of capital projects, said last week.

The greater flow of water should also keep the lake water level higher, Clemens said, with the goal of keeping the water surface much closer to the sidewalk level. The increased flow is also expected to carry away some of the decades of muck and silt accumulated on the lake bottom.

Funding to improve the water quality is being pursued through a $100,000 grant application with the National Fish and Wildlife Foundation. The request was signed off on by City Council last week and requires a $100,000 match.

The lake, though man-made and isolated, has been known to attract mullet, a wayward red drum or two, as well as the occasional river otter. Its current main water supply now is the largely hidden Comings Creek, though oyster growth and other obstructions have affected the water flow in.

Colonial Lake has been a featured part of the city almost since its beginnings. By the 1880s, the 9.5-acre lake was fully enclosed, becoming a popular relaxation draw and considered an urban promenade.

“Fishing, swimming and boating were popular but increased urbanization of the area impacted the water quality and use declined,” the grant application says. Historical pictures from decades ago indicate the water level inside the lake was traditionally much higher.

Cyrus Buffum, executive director of the nonprofit Charleston Waterkeeper, said his group has done some studies of the lake and found that algae growth and low oxygen content — conditions that often accompany shallow, slow-moving waters — are two of the biggest obvious overall health issues.

While the water improvements are in the works, funding for the other parts of the overall Colonial Lake improvements has not been set, though the Charleston Parks Conservancy is working to address that. Executive Director Harry Lesesne said more announcements on the green space effort will come in 2013.

Reach Schuyler Kropf at 937-5551.