Care, value top considerations in river dredging

About 15 different contractors representing eight different firms gathered at the Saratoga Town Hall Dec. 8 for an informational session on a project to clear Platte River gravel bars near the HWY 130 bridge. The project has long been on the town docket, but previously undisclosed details about its execution were released at the pre-bid meeting.

Laying out the parameters of the operation were Saratoga Mayor Ed Glode, council member Richard Raymer, director of public works Jon Winter and an independent consultant named Jon Nelson. Of these four, Nelson and Winter were the ringleaders in the room, carefully going through a four-page packet handed out to the contractors and answering their questions.

After the meeting, the group was given a tour of the work site and county property where dredge material is to be disposed of.

Timing Key

As explained in the meeting, bids for the project are due by 4 p.m. Dec. 15. Interviews with contractors will be held the week of Dec. 19 and a final selection will be made Dec. 23. Work is to take place at some point between Dec. 26 and March 7, but must be completed within a two-week window.

The “DEQ (Department of Environmental Quality) Turbidity Waiver is going to have a 14 day fuse,” Nelson explained the timetable. In other words, the Town has received permission to increase sediment levels in the water during the project, but only for a two week period. The two weeks only include working days.

Winter indicated there may be some flex in this requirement if unforeseen developments delay work. “(DEQ) is not going to stop the project three quarters of the way through because we’re at day 14 and we’re going to be done day 15,” he said.

By contrast, Winter described the March 7 deadline as non-negotiable: “It’s a black and white requirement. No gray area in that.” Per Wyoming Game and Fish Department (WGFD) regulations, work cannot be conducted in this part of the Platte during rainbow or cutthroat trout spawning season. “As a Class I stream, the river has stipulations in terms of what you cannot do,” Winter said. “We’ll make every effort to get in and out (quickly),” he summed up.

A privately-funded bank stabilization effort will be going on at the same time and in the same area, so the winning contractor will have to coordinate efforts with that crew. If the town contractor has to idle their operations to avoid interfering with the private operation, they will be compensated for the down time.

A Cofferdam

and a Ramp

Indeed, time frame is only one of several logistical and regulatory hurdles the winning contractor will have to overcome. The project also calls for the construction of a ramp for equipment to access the river with and a “cofferdam” to lessen water flow through the construction area. Both structures will have to adhere to requirements laid out by regulatory agencies and must be removed following project completion.

The cofferdam will connect the upstream edge of the largest gravel bar to the eastern shore of the Platte, effectively shunting water toward the center of the river channel. This will mostly dry out the construction zone and stop churned-up sediment from washing downstream. Two-ton “super sacks” that can be filled with sand have been made available by the Town for construction of the cofferdam.

The ramp will be located directly downstream of the cofferdam and must be constructed to U.S. Army Corps of Engineers (USACE) standards listed in the town’s Nationwide Permit #33.

“The biggest caveat that you guys need to be aware of is that the material used for that ramp cannot come out of the river. So you can’t just go in and pull up some of that rock (from the gravel bar) and build yourself a ramp,” Nelson warned. Forty cubic yards of rock will be furnished by the town for the ramp, and like the cofferdam, the ramp must be fully removed after the project is done.

Concerns for River

and Road

Once the cofferdam and ramp are in place, the winning contractor can start actually removing the bars, which are estimated to contain 6,000 cubic yards of material. According to the packet handed potential bidders, one of the challenges of the in-river work is that “material within the river, once initially disturbed, must be immediately removed from the river.”

“You cannot move material around. You basically dig it up and place it in a truck and haul it off site,” Winter explained of the USACE stipulations. “We have to be very, very cautious about what we do,” he continued. Winter and Nelson repeatedly stressed the need for care in attending to this requirement and elaborated that the rule would preclude in-river stockpiling of dredge material or the building of haul roads.

Refueling or servicing equipment in the river channel is also prohibited, and all equipment must be clean and inspected before entering the Platte, Nelson told the room.

Sharp Street, which the contractor will use heavily while accessing the river and hauling away material presents another potential trouble-spot. “The sticky nugget is that the road’s not rated for the work you’re going to be doing,” mayor Glode said. A weight limit of 30,000 lbs. for single-axle trucks and 50,000 lbs. for tandem-axle trucks will be imposed.

“It’s fair to say we anticipate some damage (to Sharp Street),” Nelson allowed. The contractor will be responsible for repairing any pavement damage “that is deemed by the Town to have been caused by careless (sic) of the Contractor,” the packet reads. The contractor is also responsible for locating any utilities and making sure work performed does not damage those.

Value Engineering

Because of the complexity of the rules governing bar removal operations, contractors were asked to include with their bid packages reference to previous river or stream projects they had completed. The contractors were also encouraged to be creative in finding “value engineering” solutions to possible trouble areas like thin asphalt on Sharp Street.

The potential for damaging town property or running afoul of knotty regulations is “why we’re looking at a ‘best-value proposal’ instead of just a low bid,” Nelson said.

Care and attentiveness will be critical to successful execution, and town officials seemed more concerned with hiring a conscientious operator than finding a cheap deal carrying more risk.

Though bids have yet to be submitted, Glode recently estimated the total price tag as under $100,000. Citizens will likely find out the final figure when a winning bid is selected Dec. 23.