Posted on October 31, 2016
By Howard Yune, Napa Valley Register
The long-awaited dredging of the Napa River has been on hold since early October but is expected to resume next month after a federal contractor returns from another project on the Pacific coast.
Clearance of silted-up river stretches has been suspended while Ahtna Engineering Services completes another dredging job at Noyo Harbor, the port area for Fort Bragg in Mendocino County, according to the Napa County Flood Control and Water Conservation District.
After completing that job, crews are scheduled to return to Napa on or before Nov. 11 to excavate sections of a 13-mile river stretch south to Vallejo, Pamela Patton, project manager for the U.S. Army Corps of Engineers, said Thursday.
The local delay resulted from different state-mandated work deadlines at the two sites to protect fish and wildlife, according to Rick Thomasser, operations manager for the Napa County Flood Control and Water Conservation District. Because excavation at Fort Bragg must be completed by the end of October, the Alaska-based Ahtna company is spending the month there before heading to Napa, where a state permit gives its workers until Nov. 30.
Estimated at $4.5 million, the Napa River project is meant to reverse years of silting that have created dangerously shallow conditions, which have hampered navigation and led to the Napa Valley Yacht Club’s cancellation last December of its Christmas-season Lighted Boat Parade.
Before moving out of Napa, Ahtna had begun excavating the river in mid-September, removing 10,000 cubic yards of sediment mainly from Napa’s downtown dock to Jack’s Bend near the Napa Valley Yacht Club, according to Thomasser.
The project, overseen by the U.S. Army Corps of Engineers, is the first clearance of the Napa River’s navigation channel since 1998. About 60,000 cubic yards of sediment will be removed from various sections of waterway to create a minimum 9-foot depth from Napa’s Third Street bridge to Asylum Slough near Highway 37 in Vallejo, Patton said.
Riverbed spoils are being deposited at two locations: one off Imola Avenue and another on the future site of the Napa Pipe housing and retail development.
Dredging is expected to last one to two days in each successive work area from north to south, and equipment noises will reach 90 decibels with occasional spikes to 100 dB, the Corps has said.
Despite the pause in clearing the Napa River, early work already has allowed the Napa Valley Yacht Club to host boaters from clubs in San Rafael and Rio Vista this fall, according to Commodore Steve Vartan. The Napa club also expects to stage its Lighted Boat Parade as scheduled on Dec. 3, he said.
Elsewhere on the river, Napa completed another dredging project Oct. 21 at the heavily silted Kennedy Park boat ramp, the city reported. A slip at the boat launch will be replaced at a cost of $37,000 during the week of Nov. 7, according to Kristen Hoy, junior engineer in the city’s construction division.
About 5,500 cubic yards of sediment from the boat ramp is destined for an open-water disposal site in the Carquinez Strait, west of the namesake bridge linking Solano and Contra Costa counties.
Because the Kennedy Park ramp is outside the Napa River’s navigation channel and ineligible for federal funding, the city is picking up the $200,000 cost.
Source: Napa Valley Register
