Mayor Rahm Emanuel is vowing to double — to 11 miles — the “publicly-accessible riverfront space” he has created to bolster Chicago’s unique standing as a “two-waterfront” city.

“The riverwalk and [four new] boat houses are just the beginning, an initial down-payment,” Emanuel is prepared to say, according to a text of the mayor’s Monday address obtained by the Chicago Sun-Times.

“The decisions we make in the next two to three years will shape the Chicago River and its future for the next 20 to 30 years.”

Implied but not stated was the decision Chicago voters will make in the mayoral election — now just 10 months away.

The mayor’s plan includes a host of improvements to the downtown Riverwalk east of State Street to bolster a wildly-popular — and, the mayor claims, money-making — attraction that former Mayor Richard M. Daley envisioned, but Emanuel carried over the finish line.

Emanuel is also talking about building a new trail from Chinatown’s Ping Tom Park to the west end of the Riverwalk at Lake Street.

But the mayor will stop short of embracing the ambitious and costly plan championed by two North Side aldermen to carve a 24-acre public riverfront park out of the North Branch Industrial Corridor.

Instead, Emanuel will stick to commitments he made in the “North Branch Framework Plan” unveiled before the corridor’s 760 acres of previously-protected industrial land were opened to residential and commercial development.

“The North Branch plan will create 60 acres of publicly-accessible open space. There will be new fields. New networks of riverfront trails. An extension of the now-nationally famous 606,” the mayor is expected to say.

That’s not enough to appease Ald. Scott Waguespack (32nd) and Ald. Michele Smith (43rd) and their coalition of architectural, environmental and neighborhood groups.

To confront a shortage of park space and accommodate an avalanche of new residents and employees, they want to make a park out of the last big parcel of available land in the North Branch corridor before developers gobble it up.

Renderings of their park concept show a sparkling green jewel of nature trails, play areas, athletic fields, a boardwalk and plaza, a boat launch and more, all nestled on the east bank of the Chicago River from North Avenue on the south to the widely used 606 Trail on the north.

“What we’ve been talking about for years is trying to get public space that’s contiguous or a larger footprint. That’s what the public wants up here,” Waguespack said.

“That 30-foot setback he’s talking about would be 20-plus acres. That’s how they’re calculating it. The other [40 acres] are these little pocket parks, which could be … corner spaces on a property that aren’t always publicly-accessible.”

Two years ago, Emanuel unveiled a park improvement plan he called “Building on Burnham” plan, a nod to Daniel Burnham’s admonition: “Make no little plans.”

It called for ending the dangerous free-for-all between cyclists and runners along two widened stretches of Chicago’s lakefront bike path, a project due to be completed in November, thanks to a $12 million gift from hedge-fund billionaire Ken Griffin.

The mayor’s plan also called for creating a pool and event space at 31st Street Beach Harbor, improving the concert area at Montrose Beach, adding a new triathlon training space at Ohio Street Beach, building a state-of-the-art climbing wall at Steelworkers Park in South Chicago, adding lakefront gathering places, increasing access to the Chicago River “at almost every mile” from the Evanston border to Little Village, and establishing a goal of increasing protected natural areas from 1,400 to 2,020 acres by 2020.

Last fall, Emanuel broke ground for 312 RiverRun, a project connecting four North Side neighborhoods and three parks with nearly two miles of new bike and pedestrian paths along the riverfront.

The mayor calls it “the best of the riverwalk and the 606 in one, unified vision.”

On Monday, Emanuel will unveil the “new plan” for open space.

The speech will be delivered at the $16.9 million XS Tennis Village built by the nation’s largest minority tennis organization on a site that once housed the CHA’s Robert Taylor Homes, in the 5200 and 5300 blocks of South State Street.

The tennis megacenter could not have been built — at a cost 72 percent higher than the original estimate of $9.8 million — without plenty of city help.

That includes CHA land, a $2.9 million tax-increment-financing subsidy, $7 million in New Markets Tax Credits, private loans, foundation grants and a last-minute fundraising push from Emanuel.

The state-of-the-art center includes 27 indoor and outdoor tennis courts, a 10,000-square-foot gym and a 5,000-square-foot academic center that includes training space and classrooms.

“When we make the lake more accessible or reconnect parts of the city with the river or build a new sports center like XS Tennis, that is not just something we do for Chicago this year or next. It’s what we do for the next generation and the generation after that,” the mayor is expected to say.

“Communities including Bronzeville, the Quads, Kenwood and parts of Hyde Park were cut off from the lakefront. By adding and rehabilitating bridges at 35th Street, 39th Street, 41st Street and 43rd Street, we are putting an end to that inequity.”