The blue, round coastal evacuation route signs that first started cropping up in the area more than a year ago may come in handy sooner than you think.

Some experts say the city is due for a Category 4 hurricane within the next 10 years and the city’s Office of Emergency Management (OEM) provides an unvarnished prediction of what that could look like: Imagine Canal Street under 22 feet of water, Coney Island submerged 20 feet or six miles of waves crashing across Flatbush Avenue.

But the OEM — formed in 1996 and more relevant than ever in the post-9/11, post-Katrina era — is taking steps to inform citizens about what emergency measures are in place.

By going to its Web site (nyc.gov/emols, nyc.gov/readyny) or calling 311, you can get a copy of brochures with evacuation routes and procedures and to find out if you live in an Evacuation Zone — areas, such as the south and east Bronx, that are at risk of flooding.

According to OEM spokesman Andrew Troisi, in the event of flooding caused by a Category 3 or 4 hurricane, people who live in Evacuation Zones (and only those in Evacuation Zones who have nowhere else to go) should use public transportation to go to one of 23 reception centers, found throughout the city. The homeless would then be taken to city shelters.

“It’s much more efficient to send people to these few sites and then bus people to shelters,” Troisi said.

Most of the Bronx is not at risk of flood damage. But Bedford Park and the surrounding area, situated on high and safe ground, is home to one of the borough’s two reception centers — Lehman College, located on Bedford Park Boulevard West. (The other is CS 214 on West Farms Road.)

With its convenient access to public transportation, large parking lots and the ability to accommodate large crowds, Lehman is a typical New York City reception center, Troisi said.

Lehman College spokesperson Keisha Anderson said that up to 3,500 people could find temporary shelter in one of three campus facilities: the APEX auxiliary gymnasium, the Center for the Performing Arts, or the classrooms and corridors of Carman Hall.

“People would arrive at Lehman and then stay at Lehman for a short period of time and then city officials would take them to the appropriate place to stay overnight,” Anderson said. She added that Lehman could function as a temporary shelter for about 350 people, who would be given food, water and shelter for two to three days.

In the event of an emergency, Bronxites can get there by traveling along OEM-approved routes: west along Gun Hill Road and south down Jerome Avenue, for instance, or north up the Grand Concourse.

Signs pointing the way to Lehman have been up since spring 2004 but an influential Westchester legislator says city residents wouldn’t know what to do in the event of an emergency and that bus drivers and other MTA employees have not been trained in handling an evacuation.

“The plan that exists today will not evacuate New York City successfully,” said Assemblyman Richard Brodsky at a recent hearing of his Committee on Corporations, Commissions and Authorities. “They [residents] do not know what’s in [the city’s] plans.”

While OEM head Joseph Bruno insists the city is ready, Brodsky has called on the agency, with no success so far, to release its evacuation plans in their entirety.

An interview with one local man who wouldn’t give his last name may illustrate why greater awareness of evacuation plans among city residents might be a good thing. Louie, who lives and works a stone’s throw from several evacuation route signs on Bedford Park Boulevard, said he’d never noticed them and could offer only this advice:

“You have to accept it any time — that’s the truth. New York is very close to the water. [If a storm hits] I guess I’d go to a high building.”