State regulators are forcing St. Helena to protect the Napa River after city work crews began stockpiling construction debris in Wappo Park, adjacent to the Pope Street bridge.

St. Helena City Manager Bert Johansson received a notice of violation from the California Regional Water Quality Control Board on Aug. 22. The notice stated that because the disturbed area is larger than one acre in size, the city is required to comply with the Federal Clean Water Act and California storm water regulations.

In the notice, Thomas Mumley, assistant executive officer for the California Regional Water Quality Control Board, wrote that concerned citizens contacted the board and complained about the city’s construction activities. That, in turn, led state officials to inspect the site on Aug. 19.

“We … determined that the project meets the one acre threshold for General Permit coverage of construction projects,” Mumley wrote. “However, the city had not obtained coverage.”

The notice states that if the city didn’t comply with federal and state regulations, it faced fines of up to $10,000 a day.

Things never got that far. In a written response to the water board, Johansson said the city has complied with the letter’s requirements and developed a plan to prevent storm water pollution, which includes a program to monitor storm water leaving the site.

Johansson said the plan document is on file at the St. Helena Department of Public Works and was in place on-site by Sept. 1.

Jonathon Goldman, director of public works and the city’s engineer, said the storm water pollution prevention plan includes a long list of “best management” practices to control storm water and prevent pollution from entering the Napa River.

Those practices include scheduling work when it’s not raining, he said. Other practices include erosion and dust control.

Last week, the city sprayed water from trucks to control the dust and spent $1,100 to hire a Sonoma firm, Brocco & Sons, to spray a dust suppressant on the roadways within Wappo Park.

Both Johansson and Goldman said the stockpiling of materials at Wappo Park is part of the city’s larger project to realign Pope Street for traffic approaching the bridge from St. Helena. The first part of the two-phase project will be to build an embankment for eastbound traffic. The second phase is building the roadway, sidewalk and other surfaces.

Johansson said the first phase will be completed by Oct. 15, which is the traditional start of the rainy season. “It’s not raining now, and even if it were to rain tomorrow, none of the materials stockpiled on the site would get into the river,” he added.

Despite complaints from some citizens, including Sampson Bowers, who is running for a seat on the St. Helena City Council in November, Goldman said the city council, and therefore the public, knew about the stockpiling of materials at Wappo Park. The initial study for the project was circulated to the council, he said, and “we told the council two months ago that we were going to do this. Besides, we’re doing this in plain sight.”

Last week, city crews began clearing trees and shrubs from the area where the embankment will be built up. This week, city crews were expected to begin grading the area, which is adjacent to Napa Valley College’s Upper Valley Campus.