The director of Montgomery County's Department of Park and Planning abruptly announced his retirement yesterday, citing the controversy over mismanaged development in Clarksburg and the need for "a fresh view" of how to effectively oversee the county's growth.

Charles Loehr, 54, who ran the daily operations of the agency, which reviews all plans for new construction in the county, is the most senior official to leave since revelations this summer that hundreds of new townhouses and other homes in the northern Montgomery community were built in violation of height and setback restrictions.

A planner under Loehr's supervision, Wynn Witthans, resigned in June after she acknowledged making handwritten changes to a site plan for Clarksburg Town Center in an attempt to match it to what had been built.

Loehr said his departure, effective Oct. 31, was not forced. But it comes as fresh evidence of irregularities in construction of the 1,300-home development continues to surface.

A group of residents has discovered at least three other sets of altered plans, including one approved a few days after they told officials that the new houses did not conform to specifications approved by the county.

The latest disclosures involve two legally binding documents used in county approval of construction projects: a site plan, which details a building's height, distance from the street and other features; and a plat, which marks lot lines and other dimensions of a property.

Residents also have found at least one instance in which a plat and site plan called for nine homes, including four moderately priced units, which are generally required by the county to win approval of a project. Instead, the developer, Newland Communities, built eight market-priced townhouses and no moderately priced units.

The documents also show for the first time that more than one member of the county's planning staff approved a document that changed the site plan's height and setback requirements after the houses were built.

The papers, discovered in county files by leaders of the Clarksburg Town Center Advisory Committee, provide the latest indication of lax oversight of development in Montgomery, where residential construction is booming.

Planning officials are investigating whether luxury townhouses in Bethesda have been built higher and closer to the street than was authorized. The county also is under fire for allowing a developer to build two-car garages in new Wheaton townhouses that are too narrow for car doors to open properly.

This week, a report by the Montgomery County Civic Federation, an umbrella group of neighborhood and community organizations, cited other instances in which construction projects were completed in violation of site plans.

After asserting for several months that Newland had done nothing wrong, the county Planning Board ruled this summer that 433 townhouses and one condominium apartment building exceed height limits established by the board and that 102 homes are closer to the road than permitted by plans.

Newland and the builders that collaborated on the project face fines that could top $1 million.

Until yesterday, planning officials had maintained that one version of the site plan had been altered by Witthans. At least one of the three other versions bears the signature of Richard Hawthorne, a transportation planner who at the time was serving as the agency's acting head of development review.

There is no indication that Hawthorne made any changes himself -- nothing is crossed out on the document. But by signing, he indicated his approval of the site plan, which omits previously approved heights and setbacks.

The document shows Hawthorne's signature was dated Oct. 14, three days after residents complained to officials that buildings were too high and too close to the street. Three other signatures on the document, belonging to Newland representatives, were dated March 27, 2003, 11/2 years before Hawthorne signed.

The date of Hawthorne's signature shows that the planning agency was approving changes to documents after officials had been alerted by residents that there were problems.

Hawthorne declined to comment yesterday.

Michael Ma, a supervisor in the development review office, said he could not explain the discoveries of further discrepancies in site plans and plats.

Derick P. Berlage, Planning Board chairman, also said he couldn't address the specifics. "It is hard to respond. I don't know what did or did not happen here," he said. But he said that he is instituting procedural changes to prevent unauthorized changes to plans.

Two of the newly discovered plans were dated 2001 and 2003 and bear Witthans's signature. One includes crossed-out height limits for the second phase of construction, similar to the change Witthans has said she had made.

The documents were found among hundreds of papers residents have collected from the planning agency since they began to voice their concerns last year. They have been preparing exhibits they hope to present to the agency soon.

Loehr, who has been employed by the county for 25 years, stopped short of taking direct responsibility for the problems in Clarksburg.

"I think these events could have occurred on anybody's watch," he said yesterday in a farewell memo to staff. "Unfortunately they occurred on mine and it is my responsibility to decide what is needed to move us beyond this point."

Council member Steven A. Silverman (D-At Large), chairman of the committee that oversees planning, housing and economic development, said his focus would be on addressing "systemic challenges" in the department. "This is not a situation where people say, 'Somebody's head rolled, so everything is fine.' "

Berlage, who oversees the agency and its director, said there would be a "normal progression" for acting Deputy Director Bill Mooney -- a former senior official under County Executive Douglas M. Duncan (D) who has worked in the department for several years -- to take over Loehr's duties when he steps down.

Derick P. Berlage says he is instituting procedural changes to block unauthorized plan changes.