A major restoration of 11 miles of the Los Angeles River is on the cusp of taking a leap forward.

Tomorrow, the City Council’s Arts, Entertainment, Parks and River Committee will consider an agreement between the city and the U.S. Army Corps of Engineers that would allow for preliminary studies and pre-construction work to get underway on returning the concrete channel to a more natural state.

Under the agreement, the Army Corps and the city’s bureau of engineering would begin designing a 500-foot terrace along the western bank of the river, from North Main Street to East Cesar E. Chavez Avenue in Downtown LA. The terracing project will include ripping out the concrete banks and adding plants.

“This project will be the first time the Los Angeles River is altered by the US Army Corps of Engineers for the purpose of ecosystem restoration,” a staff report says.

The two agencies would also start creating computer models of the hydrologic conditions on the 11-mile stretch of the river from Griffith Park to Downtown to study how the river will behave post-makeover.

The agreement also calls for doing a portion of the pre-construction work needed to get started on connecting the river to the newly madeover Los Angeles State Historic Park. (This segment will eventually include a giant water wheel.)

“Much of the cost of this first design phase is due to the high level of effort to perform the modeling work,” says the BOE report.

The total cost for this first step of project is estimated to be $8.1 million, which the city and USACE are splitting. The report says “much” of the cost of this phase is because of all the in-depth modeling involved.

The army corps is asking for the design agreement to be signed by October 1, 2017. The pre-construction engineering and design work would begin immediately after that, but is expected to take about 4.5 years, depending on “annual Federal appropriations, and City matching funds,” says Paul Gomez, a city spokesperson.