It will get real busy along the banks of the Wakarusa River soon enough.

Lawrence city engineers are hoping – and perhaps keeping their fingers crossed, too – that work can get started on building a $88 million sewer treatment plant along the river this fall.

“If the weather is warm and dry, that would be really good news for this project,” said Dave Wagner, city director of utilities. “It may not be so good for some other things, but it definitely would be good for this.”

That’s because the earliest construction crews will be able to start moving dirt at the site is in late October or November. Once the ground gets frozen, work will have to stop at the site, which is on about 500 acres near the intersection of North 1100 and East 1600 roads.

Wagner said plans call for a large amount of dirt work to be done before this winter. He said that timeline now may be too optimistic.

Crews aren’t able to get started now because engineers are still determining how much dirt they’ll need for the project. This much they know: It will be a lot. Thousands upon thousands of cubic yards of fill dirt will be needed to stabilize the base of the plant. But engineers haven’t yet determined whether it will be best to bring the dirt in from off-site, or to move dirt from one part of the 500-acre site to another.

Wagner, though, insists the dirt issue isn’t one that caught city planners off guard, and it hasn’t affected the project’s budget. Wagner said soil boring that was done prior to the purchase of the property showed that fill dirt would be needed to stabilize the plant.

But Wagner said the site was the best location for the plant, despite the need for a lot of dirt. That’s because the site is lower than most other points of the county. That means as the county develops, many of the sewer lines won’t have to rely on pumps to get the sewage to the plant. Instead gravity will do the work.

“Gravity is a sewer engineer’s dream,” Wagner said. “It makes it a lot easier, and easier also means cheaper.”

All the dirt, though, may end up being an inconvenience to neighbors of the plant. There will be a lot of truck traffic to and from the site. City leaders say they don’t have estimates of just how many trucks could be traveling along the roads in the area, but they concede it will be significant.

Douglas County leaders, however, are creating some road rules for the project. Keith Browning, director of public works for Douglas County, said trucks will have to use a portion of North 1100 Road – a Wakarusa Township road – to get to the site. But the heavy trucks will be required to take either County Route 1055 or County Route 458 to get to North 1100. In other words, the portion of North 1100 road west of County Route 1055 will be off limits.

Browning said the city also has agreed to pay for the improvements needed to both North 1100 and East 1600 roads to ensure that the roads can handle the heavy truck traffic.

The city won’t be paying for any wear and tear the project causes on County Routes 1055 and 458. Browning said he does have some concern that the truck traffic will create wear on the roads, but said it was tough to ask the city to pay for those improvements.

“I have some concerns about that, but truck traffic is part of the function of those roads,” Browning said.

The entire project – dubbed as the largest project ever undertaken by the city – is scheduled to be completed in 2011. It is needed, in part, to help meet growth demands. The project is being paid for through sewer rates paid by customers.