Several hours into its Sept. 3 meeting, City Council voted 5-2 to allow the construction of the Parkside Estates development adjacent to the Rock Bridge Memorial State Park.

The proposed development, however, only passed after council members amended the plan to allow 15 percent impervious surface land, man-made surfaces such as concrete that increase storm water runoff, as opposed to the 23 percent originally allowed by the ordinance.

The amendment followed concerns that runoff from the subdivisions would potentially damage the water quality of the park and endanger native wildlife.

The stability of one species of flatworm, the pink planarian, would be threatened by degradation of the water quality in the park, according to documents submitted to the council.

Second Ward Councilman Michael Trapp spoke during the meeting about the high density of the proposal. He said he feared the development would not only harm the storm water quality but also the natural aesthetics of the park.

“We don’t know where the water is going,” Trapp said at the meeting. “We don’t know what possible features that could be put at risk of our eternal legacy of endangered species…. The parks are a treasure that I, at least, have mandate to protect.”

Sara Parker Pauley, Missouri Department of Natural Resources director, expressed concern about the impact the high-density development would have on visitors’ experience in the park.

“Rock Bridge serves the people of Columbia and the state of Missouri,” Pauley said at the meeting. “Families explore its trails…. Runners enjoy its scenic paths. (The original proposal) is not acceptable to the Department of Natural Resources or to the Missouri State Park system.”

The unique geographical features of the park and surrounding areas are particularly vulnerable to contamination, said Joe Gillman, Missouri Geological Survey director and state geologist.

“These landscapes and their hydrologic conditions allow surface water to rapidly infiltrate into these underground drainage systems and provide a direct link between surface water and groundwater,” Gillman said at the meeting. “(This) increases the potential for surface contaminants to impact water quality of underground shallow aquifers, hydrologic systems and ecological environments.”

With the finalization of the proposal last Tuesday, the project’s developer will now need to resubmit a final plan with amended impervious surface limits. The final plans will be reviewed before construction begins, said Patrick Zenner, development services manager for the Planning and Zoning Commission.