Ponds, marsh helping keep pollution at bay
Joint project is called groundbreaking effort to protect drinking water

By BILL MURPHY

MASON PARK MARSH

• Where: The city park is at 541 S. 75th in southeast Houston.

• Amenities: A walking trail on the north bank of Brays Bayou passes the project — two ponds and a tidal marsh.

Tucked away in a mostly unnoticed corner of Mason Park are a marsh and two ponds too small for recreational use by canoeists or anglers.

But the unassuming Brays Bayou Freshwater Tidal Marsh could provide part of the solution to a monumental problem facing the region: the pollution of Galveston Bay.

They are part of a demonstration project aimed at determining whether man-made wetlands can filter contaminants out of stormwater runoff and reduce the pollution that makes its way into bayous and the bay.

The Environmental Protection Agency, the county and the city of Houston are searching for ways to filter out noxious chemicals because they cause about half the pollution in Galveston Bay, said Andy Sipocz, a biologist and natural resources coordinator with Texas Parks and Wildlife.

Winning accolades
With enough of such wetlands, Galveston Bay pollution would not get worse even though the amount of stormwater pouring into bayous and the bay will increase as new subdivisions are built and regional population grows, he said.

"With all this growth, I don't know that there is much chance of reducing the pollution of Galveston Bay. But wetlands keep the pollution from getting worse," he said.

The project, a joint effort of the Harris County Flood Control District, the city of Houston, Texas Parks and Wildlife Department and other agencies, is winning accolades.

Sipocz's wife, Marissa, a biologist with the Texas Cooperative Extension who works on the project, represented her colleagues in New Orleans earlier this month, picking up a Gulf Guardian Award from the EPA's Gulf of Mexico Program.

Broken lines
The project was one of 10 named by the Sierra Club last month as groundbreaking efforts to protect drinking water.

The wetlands are treating stormwater from only one large culvert. It will send about 20 million gallons through the ponds annually.

That is an infinitesimal portion of the water flowing through Brays Bayou next to the wetlands.

Biologists, as expected, found car oil and fertilizer residue in the culvert's untreated water. Tests also revealed high levels of fecal coliform bacteria, which almost always comes from human waste in sewage, Sipocz said.

Aging sewer lines in the 15-acre watershed feeding the culvert probably are broken and leaking sewage into broken stormwater lines, a common occurrence in the county, he said.

The first pond is a settling pond, where debris sinks to the bottom. Students from Austin and Chavez high schools helped plant blue irises, bulrushes, water primroses and other vegetation.

These plants are pollutant killers because bacteria that can turn harmful microbes and chemicals into harmless substances feed off their roots.

About four days after water enters from the culvert, it flows through a pipe into the second pond. Naturally occurring bacteria in that pond further treat the water, eliminating coliform bacteria, phosphorus, ammonia, dioxins and PCBs.

After about two days, water is pumped into a man-made tidal marsh that connects with Brays Bayou.

Tests have shown that the water meets EPA stormwater standards after filtering through the ponds and marsh, Sipocz said.

Wetlands and wildlife
On a recent day, an egret and blue heron stood sunning themselves in the tidal marsh. A turtle jumped off a rock into a marsh as Sipocz approached. At other times of the day, raccoons and other animals visit.

"The wetlands have brought forth a host of wildlife," said Heather Saucier, spokeswoman for the flood control district.

The public will gain better access to the ponds when a pedestrian bridge is built over Brays Bayou, connecting the main part of Mason Park with the lesser-used section where the wetlands are, she said.

bill.murphy@chron.com

Neat article. I ran across alot of research on this topic when I got sidetracked on my senior research project in college on the effects of malathion on quahog clams. Golf course run-off has come a long way since then