We now know more about the water trails proposals in Central Iowa, a keystone project many leaders see as a crucial way to attract and keep residents and workers.

We know it would cost in the neighborhood of $100 million to revamp three downtown dams, with the Center Street location becoming an adventure park, and to create fun spots along streams across the area.

We know it’s probably a decade-or-more proposition to gain approvals, raise money and build the projects. That includes the $35 million to turn the Center Street dam area into a whitewater course wild enough to draw competitions. That and the many smaller projects could be staged. Some suburbs are already working on making rivers more accessible.

We also know it’s time to test the waters to see if federal, state and local governments would pay two-thirds of the tab as projected, and if Hubbell Realty chief and water trails champion Rick Tollakson is right that local businesses can be counted on to pay for a third of the project.

You don’t have to wonder whether Greater Des Moines Partnership CEO Jay Byers thinks the project is important. “This project is the most transformation quality of life project of our generation and we need to get done,” Byers said in an interview.

Officially, the range of costs for the area would be $98.6 million to $117.1 million and could be staged. The downtown project calls for $76 million of work in the rivers, at three dam sites, with $11.6 million to $30.1 million in work along the banks to make the river more usable.

“We are in a transition,” explained Gunnar Olson, spokesman the Des Moines Area Metropolitan Planning Organization, which has handled much of the planning in cooperation with the Iowa Department of Natural Resources and with assistance from the U.S. Army Corps of Engineers. “We have great ideas, now it’s time to see if they are actually feasible.”

Said MPO chief Todd Ashby: “We definitely think it’s doable.”

Highlights would include a surfable dam in the Raccoon River near Fleur Drive, adjustable wave action at the Center Street dam site in the Des Moines River and a more tranquil scene at Scott Street south of downtown. It’s likely Center Street area would have enough water flow in the height of the season to be open all the time, while the others might be operating more half the time, a just-released engineering study found.

Other projects include kayaking and canoeing along Beaver Creek in Johnston, a portage between the Raccoon River and Blue Heron Lake in West Des Moines, and an access to the Raccoon River along 63rd Street at the Des Moines-West Des Moines border.

The water trails crew presented an engineering study to the Des Moines City Council this morning. ISG worked on the regional projects, and McLaughlin Whitewater, with RDG Planning & Design and HDR, worked the downtown angles.

Tiffany Tauscheck, chief strategy officer for the Greater Des Moines Partnership, said various national reports have shown that millennials look at things to do in a community when they decide where to live, even before they consider job prospects.