The District could be forced to establish 30 to 55 new shelters to house the homeless if the courts sustain a ballot initiative forcing the city government to provide them with shelter, according to a new study by the Center for Applied Research and Urban Policy at the University of the District of Columbia.

The study report, which was written by associate professor Frederic G. Robinson, estimated that there are 6,454 homeless people in the city, but that space is available only for 2,330 in 30 public and privately run shelters.

The occupancy rate for the city's shelters was 77 percent on July 31, a time of the year when the weather could be expected to reduce people's reliance on them.

"At present, the average capacity is 83 persons per shelter," Robinson said in a prepared statement. "In the unlikely event that every one of the estimated 4,606 persons living in the street on July 31 sought shelter, 55 additional facilities would be needed."

The study was commissioned in connection with Initiative 17, the ballot question approved overwhelmingly by voters last year that stipulated the city must provide shelter for all who want it.

Mayor Marion Barry's administration won a ruling in D.C. Superior Court that overturned the measure, and the D.C. Court of Appeals currently is considering an appeal of that ruling.

The study appears to challenge statements by the mayor that if a shelter at 425 Second St. NW, which has an 800-bed capacity, is closed by the federal government, there still will be enough space in other shelters to absorb the displaced residents.

The U.S. Department of Health and Human Services is awaiting court approval to shut down that facility, which is operated by the Community for Creative Non-Violence.

Although the UDC study does not include about 635 spaces in shelters recently established by the D.C. Coalition for the Homeless, the study indicates an apparent gap between the homeless population and shelter capacity that is greater than the organization's facilities would be able to accommodate.

The report's estimate of 6,454, which was obtained through observation and mathematical extrapolation, is consistent with working estimates often cited by activists for the homeless.

CCNV, whose shelter is the city's largest, estimates the city's homeless population at 5,000 to 10,000, and CCNV leader Mitch Snyder termed the UDC estimate a "bedrock number."

Social scientists have been hampered in efforts to conduct a census of the homeless because of the elusive nature of individuals who have no addresses.

A nationwide study by the U.S. Department of Housing and Urban Development found that there are between 250,000 and 350,000 homeless people in the nation, but many who work with the homeless disagree with this estimate.

Robinson's study for UDC noted that it is "very difficult effectively to count homeless 'street' people."

Some of them, Robinson wrote, are "reasonably well dressed" and therefore are not discernably homeless, while some seek concealed locations to spend the night and still others live in abandoned buildings, in dark alleys or at construction sites that can be hazardous for census takers to enter.

Also uncertain is what percentage of the homeless would accept shelter if it were available for them.