This past winter, the New Haven Police Department brought scores of homeless New Haven residents off frigid streets and into city-operated shelters. Separately, charities and churches across the city distributed blankets, supplies and food, and government agencies and social services helped address their other needs.

Starting last week, these organizations have broken down their institutional walls to mobilize under the banner of the 100 Day Campaign, New Haven’s largest coordinated push to reduce chronic homelessness. Coordinated by Rapid Results Institute, a Stamford-based nonprofit consulting agency, the campaign will pool resources and coordinate actions among groups already serving the homeless.

“Rapid Results wants us to be thinking ambitiously,” said the Director of Housing & Homeless Services Steve DiLella, one of the leaders of the new partnership. “If agencies break down barriers and galvanize behind the same model and goals, we can have a dramatic effect on housing a significant portion of chronically homeless people.”

The initiative kicked off last week at a two-day “boot camp,” where organizations convened to draw a blueprint for the 100-day program. Led by Leigh Shields-Church of the Connecticut Mental Health Center, a team of providers created a comprehensive plan to identify, document, house and support New Haven’s chronically homeless population.

A leadership council within the campaign, composed of stakeholders and executives, will oversee and help implement the initiatives.

Their goal is to house 75 percent of New Haven’s estimated 140 chronically homeless people in the next 100 days or by July 30.

In coming week, teams will identify and register homeless individuals in and around New Haven, ranking their risk level. Individuals deemed “chronically” homeless — having spent either a year on the street or three years with unstable housing — will receive the highest priority for housing.

“We want to create a system that people can access easily,” Shields-Church said. “People are receiving services from multiple sources. We want to provide them with quality and cost effective services.”

Though the initiative will have a lasting impact on homeless people and the services that support them, it will require very little outside funding, Shields-Church said. Rather, the organizations and agencies will pool together their existing money and resources in order to work more efficiently.

The investment will have a great social and economic return as well, DiLella said. The expenditures associated with providing homeless people with supportive housing will be outweighed by savings on shelters, criminal justice, social services and healthcare, he said.

“It’s a win-win all around,” he said. “The cost of having someone homeless for a day is astronomical.”

According to a 2007 study on supportive housing in New York City, “each unit of permanent supportive housing saved $16,282 per year in public costs for shelter, health care, mental health and criminal justice. The savings alone offset nearly all of the $17,277 cost of the supportive housing.”

As for the city’s role, municipal administration will help identify prospective housing for homeless people and provide administrative support, said City Hall spokesman Laurence Grotheer. City Hall Chief of Staff Tomás Reyes serves on the leadership council.

“The mayor is hopeful the spirit of cooperation and collaboration that characterized the recent two-day workshop will yield practical solutions for those struggling to find a place to call home,” Grotheer said.

The coordinating organization, Rapid Results Institute, is known for its 100-day campaigns abroad, coordinating charities and NGOs in developing countries to provide drinking water and reduce environmental impacts. Recently, Rapid Results has applied its strategy to tackle homelessness in cities across the U.S., in the wake of federal legislation that pushes states to reduce homelessness.

In Rapid Results’ 100-day initiative in Los Angeles in 2013, providers secured leases for 35 chronically homeless people within the first nine days of the program’s start.

Approximately 430 sheltered homeless people live in New Haven as of Jan. 30.