A water pressure problem has sent work crews rushing into some of Hampden's busiest streets — including Falls Road and The Avenue — for an emergency water main replacement that Baltimore City officials said is expected to last about a month.

Low water pressure in the area of Buena Vista Avenue and West 41st Street prompted a review by the Department of Public Works.

"It was determined we have to do a water main replacement on Falls Road between 36th and 41st streets," spokesman Kurt Kocher said.

Contract workers from Spiniello, which specializes in infrastructure rehabilitation, were out in force between Roland Avenue and Falls Road late last week, hooking bypass pipes to fire hydrants and connecting businesses and residences to the hydrants for temporary water supply. Buena Vista and Union avenues are also expected to be affected.

A sign posted on a tree near the intersection of Falls and 36th warned pedestrians, cyclists and motorists to use caution when navigating around the above-ground, temporary water system.

Kocher said road closures and detours are expected "block by block" on Falls Road during construction to replace 4-inch, 6-inch and 10-inch mains He said the city will try to minimize the impact on merchants in one of the neighborhood's biggest commercial areas, including the temporary loss of parking.

But he added, "There's not good time to dig up and replace water mains."

Pipe replacement is not expected to start until mid-September, after Hampdenfest on Sept. 14. Kocher said.

The work came as a surprise to area merchants, who were not informed until shortly before the work began, said Benn Ray, president of the Hampden Village Merchants Association and co-owner of Atomic Books, located on Falls Road overlooking The Avenue.

Ray said he noticed orange construction cones on the street Monday, Aug. 26. 26, the same day as a city letter informing people of the project.

"There was no advance notice," he said.

The effect of the early work on business at Atomic Books was noticeable immediately, Ray said Aug. 29.

"We've been dead all day long because no one can park and get in," he said. "You have giant water pipes running down the street."

Ray said he hopes crews will finish the job as quickly as possible.

"I expect them to treat it as an emergency," he said.

This is the second emergency project in as many months that city officials say is attributable to aging infrastructure. Last month, the city repaired a 25-foot deep sinkhole on Keswick Road near 37th Street, caused by storm-drain damage and erosion, Kocher said.