CONCORD -- A proposed church on San Miguel Road threatens to transform one of the city's last rural roads into one with traffic jams and noise, neighbors say.

The city has received 239 pages of responses from residents, most opposing St. Mary and St. Mina's Coptic Orthodox Church's plan to build on 3.39-acres at 930 San Miguel Road, near the Contra Costa Canal and trails.

Residents say the big development and the people it will bring do not fit with the narrow gravel roads and leafy open space that surround the project site. The site is currently zoned for residential homes.

"We are not against the church as an entity. What we are against is that project, those four buildings and how large they are in such a small footprint and what the impact will be today and in the future," said John Pelosi, a member of Friends of San Miguel Road, which objects to several aspects of the project.

Church officials did not return calls for comment as of Wednesday morning.

The project is years in the making -- the church dedicated the land in 2001 after acquiring it from a developer whose project to build four homes there gained city approval but was never built.

The church, which is currently at 3500 Clayton Road, plans to build a 13,020 square-foot sanctuary to house 297 people, a 2,840-square-foot classroom building, a 6,280 square-foot multiuse building and a 1,140-square foot chapel. All buildings would be one story; the sanctuary, at 42 feet, would be the tallest structure.

An initial environment study -- what the government calls a mitigated negative declaration -- found that the project would create certain environmental impacts, but all could be mitigated through recommended measures.

Save Mount Diablo and neighbors, however, are asking the city to perform a full environmental impact report, which requires deeper study of potential impacts. One neighbor submitted a petition with 106 signatures asking for the full review.

"The city really dropped the ball," said Mike Pelosi, John Pelosi's son and a neighbor to the project himself. "To me it's so obvious that a full (environmental report) needs to be done and anything else would be irresponsible."

Among neighbor concerns are impacts to wildlife, increased car traffic near a trail along the canal and on the windy, two-lane San Miguel Road, and access to the church from San Miguel Road. Drivers would need to take a driveway from San Miguel Road and a bridge over the canal to reach the church.

According to the proposal, the church would need to use Diana Hunt's driveway, but Hunt said she has never been contacted.

"It's our safe haven," said Hunt, who has lived there 37 years. "I definitely won't feel it's our safe haven if we have all these cars going 15 feet from my house."

The proposal will be heard before the Planning Commission at a yet-to-be-decided meeting. It needs approval from the city, U.S. Bureau of Reclamation, U.S. Corps of Engineers, California Department of Fish and Game, the Regional Water Quality Control Board and the Contra Costa Water District.

"The city's planning office serves as the gatekeepers," wrote Pamela Fischer, whose family has owned a home near the site for 50 years. "Their job is not just to mind the P's and Q's but also to guard against inappropriate use of land and to protect neighborhoods by keeping to the master plan of intended use ... This issue appears to require an act of courage on the city's part, to be the voice of reason and justice."

David DeBolt covers Concord and Clayton. Contact him at 925-943-8048. Follow him at Twitter.com/daviddebolt.