They worry about what may happen downhill in the Head of Westport village when the big one — a once in a century deluge — strikes. Still, the Planning Board last week voted unanimously to approve a proposal by Energy Development Partners of Providence for a 6.4 megawatt solar energy facility at 536 Old County Road, the 36.7-acre home of Westport Sand and Stone which is now inactive.

The approval, with conditions, came at the close of the board’s fourth meeting on the subject and after the developer made a number of changes to satisfy drainage and other concerns voiced by board members and a few neighbors.

Board member Robert Daylor, who had proposed some of the drainage changes, said he was conflicted.

The board, he said, also represents “the people who live at the Head. In the natural world, that water wants to flow down to the river.

“You show that there is a reduction in impact from your project,” he told the developer, “and that’s the end of the story.

“But the real story is that the (retention) pond probably doesn’t hold the 100-year storm … The world ends at the pond in your calculations.” When it overflows, where does the water go? Down the street.”

If the solar site abutted the river, it would be simpler. “But we’ve got the village sitting between the project and the river. I just have this discomfort.”

When people say later that things didn’t turn out as the developer projected, if someone gets hurt or “there’s a foot of water in the basement of the Congregational Church, “I just want to be able to tell them that we did everything we could to safeguard them

At the same time, Mr. Daylor said, “I think this is a fabulous re-use of the property. All of this is exactly what we want to do” with solar.”

In then end, Mr. Daylor made the motion to approve.

Board Chairman James Whitin shared concerns about drainage and ability of that pond to contain runoff.

“It isn’t the 100-year storm, it is the ones in between that we are more likely to have,” that worry him, Mr. Whitin said. “The level of that pond in January was a foot and a half from the top. I don’t know what kind of storms we had before that but I don’t think we had 100-year storms.” He did, however, acknowledge that what is proposed is a “significant improvement” over what is there now.

Alan Benevides, senior vice president and civil engineer for the Woodard & Curran engineering firm, said he understands the concerns but stressed repeatedly that, after site changes are made, the sand and gravel pit property will produce much less runoff than is now the case.

“The project significantly improves what is there. I’m confident that the numbers we have presented are not only accurate but are conservative,” he said. At present, water flows quickly down the bare and hard-packed gravel property, he said, but the land will absorb much more water once it receives a 4-inch layer of topsoil and vegetation. There will also be swales and drainage pipes to help guide water to the pond.

Board member David Cole voiced support for the project.

In a 100-year storm, water will descend toward the village from all directions, not just from this property, he said. “With this project, the property will make less of a contribution (of water runoff) to this area than it would now.

“It’s a win-win,” Mr. Cole said. “We are getting a solar farm and we are getting an improvement in the potential effect of a 100-year storm. That makes me pretty comfortable.”

No neighbors spoke at this final hearing.

Changes made

Project manager Ben Aparo began the meeting by listing changes already made to the plan in response to concerns and recommendations.

• The eastern edge of the project will receive a “fairly comprehensive evergreen screening across that whole boundary, about 100 trees,” even though the solar panels would likely be out of sight anyway.

• To prevent someone from falling off and getting hurt, a large retaining wall in the middle of the property will be blocked off by the same 7-foot fence that will surround the property. Board members asked whether it would be better just to tear the wall down but were told the slope would be too great to add solar panels and the cost would be high.

• Debris and machinery, including the old scale house and garage, will be removed.

• To improve drainage, culverts will be increased in diameter, a water ditch will be added along the east side, and additional swales will be included.

The developer also agreed to a couple of additional requests from Mr. Daylor, including a new drainage trench through the middle of the solar arrays.

The project

The property, Mr. Benevides said, contains 36.7 acres zoned residential/agricultural. The work area would cover 15.6 of those acres and the fenced solar panel area would be about 14 acres.

That would leave about 57 percent as open space, he said.

A corner of the property, not part of the solar development, is within an aquifer protection district, and there is a fairly large pond on the site as well as wetlands.

The solar panels would stand a maximum of 11 feet tall and there would be a 100-foot buffer to the property lines — solar panels would be 120 feet to the property lines at their closest.

“Much of the land has already been disturbed — it’s a gravel pit,” Mr. Benevides said. That, he added, means that the project would require less clearing of trees than most, about 2.9 acres of mostly smaller trees that have grown back over once-cleared areas.

Traffic would be negligible, he said, just occasional visits for mowing and maintenance, and the only sound would come from the transformer. No pesticides or herbicides would be used.

The plan also calls for improving the look of the entrance with grass, shrubs, more attractive fence and a facelift for the building.

“In my opinion, what’s being proposed here” should be an improvement for those living nearby, Mr. Benevides said, especially the elimination of big trucks coming in and out.

“I know solar projects are controversial but at the end of the day they are generally pretty good neighbors.”