Anne Arundel County is not expected to start dredging Mill Creek until late 2009, nearly four years after 3 million gallons of sewage and sediment were dumped into the waterway.
County officials will share with residents at a meeting tonight their plan to deal with the aftereffects of the spill and chronic urban runoff, which has raised the creek bed and narrowed the entranceway for boats into the Magothy River.
The Department of Public Works will present a year's worth of monitoring studies and discuss progress in obtaining dredging permits to excavate the sand and sediment. Officials also will address the causes of high bacteria levels that prompted the Health Department to ban swimming and fishing in the creek for part of last year.
"Everyone who lives on Mill Creek is concerned about the health issues," said Tom Dent, founder of Save the Creek, a residents group formed to monitor the cleanup of the creek.
Since the spill in December 2005, the water level near the pier of his home along Mill Creek has dropped at least 8 inches. Dent worries that if the water level falls further, he will not be able to take his powerboat down to the Magothy River. Homeowners are also worried about their property values as well as their health, he said.
Juliet Page, who lives farther down the creek in Divinity Cove, said the water level at her and her neighbors' pier dropped from 5 feet to 3 feet. For now, her neighbors have been doing their own "propeller dredging" - using their boats' engine propellers to dig paths through sand and sediment.
Page, who is active in Save the Creek, is a member of a county committee discussing the source of bacteria polluting the creek and studying possible solutions.
"It's actually been very enlightening to see how much work has been done behind the scenes," Page said.
The spill was caused by a buildup of sewer gases that eroded parts of a concrete reinforced pipe at the Mill Creek Pumping Station, said Chris Phipps, chief engineer in the Department of Public Works.
When the hydrogen sulfide gas mixed with water, it became sulfuric acid and ate away the pipe's interior, collapsing the pipe and sending the untreated wastewater spewing out. It took 24 hours to stop the flow.
The spill alerted the Department of Public Works to potential gas buildup in other parts of the pipeline. The department identified 8,000 feet of pipe that needed immediate attention, Phipps said. It has replaced the interior of 6,000 feet of pipe with a resin liner that is not susceptible to corrosion, he said. The last 2,000 feet of pipe restoration at Shore Acres Road and College Parkway will be finished in the next two to three weeks.
The Department of Public Works has spent $3.4 million on pipeline restoration, Phipps said. Monitoring and sampling for water quality will cost more than $200,000. Bayland Consultants & Designers Inc. in Hanover has been contracted to do the studies.
Bayland is comparing Mill Creek with Dividing Creek, another tributary of the Magothy River that was not affected by the spill, to assess the long-term effects of the sewage spill, Phipps said.
Researchers found that both tributaries have high bacteria levels after a heavy rainfall, something that is common to rivers throughout Anne Arundel County, Phipps said.
They have concluded that the bacteria problem is coming from nitrogen and phosphorus and other chemicals being washed into the river from septic tanks, fertilizer chemicals and animal feces.
"Mill Creek is not that different from other creeks," Phipps said.
The county also still has to deal with the sediment deposit caused by the spill.
The state Department of the Environment and the Army Corps of Engineers wanted the county to submit a dredging proposal that would fix the problem caused by the spill and eliminate other sediment deposits caused by runoff, Phipps said.
The county still is studying the proper depth and width of the creek to make sure all of the dredging can be completed at once.
To avoid disrupting fish habitat, dredging can be completed only in the winter. With the time it takes to get permit approvals, the earliest the dredging can be scheduled would be the winter of 2009, Page said.
Phipps said it was premature to estimate the cost.
The meeting is scheduled for 7 p.m. today in Room 101 of the Florestano Building on the Arnold campus of Anne Arundel Community College. A tape of the meeting will be aired on Channel 98 later in the week.