A 20-foot embankment that collapsed behind Annapolis Mall 12 days ago releasing silt and construction site runoff into Weems Creek apparently met state design standards, prompting county officials to challenge those standards yesterday.
"Our first indications are, it may not have happened if there had been tougher standards," said Tom Andrews, the county's chief environmental official. "If there had been concrete pipe instead of corrugated metal, it may have helped."
County Executive Robert R. Neall has ordered the Department of Public Works to inspect all 186 county-owned, storm water and sediment control ponds within the next 30 days to ensure there is no danger of additional failures, said Mr. Andrews, who oversees the Public Works and Utilities departments and the Office of Planning and Zoning.
Ponds within the Chesapeake Bay Critical Area, a 1,000-foot protected strip along the bay and its tributaries, and other environmentally sensitive areas would receive priority attention, Mr. Andrews said.
Storm water ponds are intended to capture eroding sediments that can clog recreational boating channels and suffocate aquatic plants and animals.
Mr. Neall also has ordered Public Works officials to develop rules for the construction of future county-owned ponds that exceed state and federal standards, Mr. Andrews said. Numerous privately owned ponds, built and maintained by developers or neighborhood associations, would be unaffected.
Meanwhile, the county has hired the Robert B. Balter Co. of Baltimore to "pinpoint the exact causes" of the March 4 failure, he said. The pond behind the mall will be rebuilt using the new standards to prevent a repeat of the incident, Mr. Andrews said.
The embankment, part of a pond designed to control erosion from the county's Bestgate Road construction and the expansion of Annapolis Mall, collapsed under heavy rains; a 54-inch-wide corrugated metal pipe meant to carry clean water from the pond to a tributary of Weems Creek was crushed.
The pond became the focus of a fight between Annapolis Mall and Woodward & Lothrop, which has a store a half-mile away in Parole, last year. Woodies' officials maintained that the pond was improperly designed.
"We raised these issues a long time ago, and people were so prepared to stick it to Woodward & Lothrop, they wouldn't listen to the merits," Neil T. Proto, Woodies' lawyer, said yesterday. "Never once was there a public hearing on this."
Mr. Proto said he believed the county would never release any report that placed blame on county or mall officials for the pond's failure.
The Weems Creek Conservancy, which sued the State Highway Administration four years ago to stop the flow of mud from the U.S. 50 expansion into the creek, is keeping a watchful eye on the county's progress.
"We absolutely have to have some assurance it won't happen again," said Elizabeth McWethy, president of the Conservancy.
"That's got to be the bottom line; it's got to be able to do what it is supposed to do," she said.
Robert B. Balter will be joined in the investigation by the engineering firm Rummel, Klepper and Kahl, consulting firm Wallace, Montgomery and Associates, Public Works engineers and state dam safety officials, Mr. Andrews said.