This briefing paper from the National Recreation and Park Association provides guidance on financing green infrasturcture projects. The key messages were:
#1 The budgeting process must consider the differing life cycle characteristics between green and gray infrastructure.
#2 Local taxes, user fees, and stormwater utility fees are suitable for both capital and O&M expenses.
#3 Grants and state revolving funds or other low- to zero-interest loans may fund planning and capital costs.
#4 Nontraditional sources of financing, such as public-private partnerships and nongovernmental funding, allow communities to leverage public funding against foundation, corporate, and community contributions.