go buy some of the empty oil field camps in North Dakota, you can buy a fully furnished 550 bed self contained worker camp for under 3 million.  It could be set up and opened in Under 2 months.  Make the residents submit to treatment and hair follicle testing in order to live there. That will ensure the camp will stay empty.  since the city will have so many empty rooms available the police can sweep the camps with no worries about bed shortages.  Life needs to be so crappy "outside the shelters" that sobriety seems acceptable, the working homeless will have a nice clean facility to help them bridge to housing.  They are built with wings so each wing can keep populations separated by their needs.