Nothing that literally compels them to spend the money, but they are required to set up a committee (populated in part from other relevant city boards/commissions) which collects proposals and recommends which to fund. City council would ultimately approve the use of those funds. No reason the city shouldn't want the extra cash to spend, though. Also the new affordable housing trust can be allocated CPA funding to help with projects they choose to support. (Source: used to work as a planner developing CPA plans).