A mediator appointed by Mayor Marion Barry has ruled against a group of Northwest Washington residents who have lobbied for the removal of eight-foot-high antisuicide fences from the Duke Ellington Bridge on Calvert Street NW.

Diana L. Herndon, an attorney with the D.C. Department of Consumer and Regulatory Affairs, held two days of hearings in July before finding in a ruling issued late last week that the barriers, erected in January 1986, should remain.

In an 11-page opinion, Herndon wrote that "erection of the barriers is a project of special merit that must be balanced against the damage done to the architectural integrity of the bridge."

The current design, which features curving silver-colored bars, she wrote, "represents a compromise between the legitimate public safety concerns of the {city} and the architectural integrity of the bridge."

The fences run the length of the Calvert Street span, which overlooks Rock Creek Park and was the site of 24 reported suicides from 1979 to 1986. Residents of the Kalorama area have argued that the new fences are an eyesore and only encourage people trying to killthemselves to search out another way to do so.

But Herndon rejected that argument. "The evidence presented persuades me that jumping off a bridge to commit suicide is likely to be an ambivalent, impulsive act which could be deterred by a physical barrier," she wrote.

Patricia Wamsley, an advisory neighborhood commissioner who has opposed the fences, said that no decision has been made on whether to appeal Herndon's order to the D.C. Court of Appeals.

Herndon's decision represents a significant setback for the neighborhood residents who were heartened by a D.C. Superior Court ruling in March granting their request for a new hearing on the fences.

Judge Ronald P. Wertheim found that the city violated its own procedures when it granted the permits needed to build the fences without first soliciting citizen comments on the proposal.

Two Advisory Neighborhood Commissions have opposed the retention of the barriers, and they were joined in their attempt to have them removed by D.C. Council members Jim Nathanson (D-Ward 3) and Betty Ann Kane (D-At Large).

"I'm sure the citizens are very disappointed and I'm disappointed for them," said Kane.