Making the Case for Green Versus Gray…and Trees Too!

Adopting green infrastructure practices – particularly as part of an integrated system – almost always will save on construction costs and maintenance over the long term. So how can you prove it?

More Technical

For an overview of the various methods for measuring flow reduction associated with green infrastructure, see this recent draft paper from the Center for Watershed Protection, prepared in 2017 for the US Forest Service. The project demonstrates how existing hydrologic models can be modified to accommodate green infrastructure and trees, and assesses other methods to measure the functions, benefits and economics of green infrastructure.


Less Technical, Still Useful

Below we’ve listed some case studies which include cost analyses for gray versus green practices. And we urge you to tinker a bit with some of the calculators; they may be just what you need to show your colleagues why green infrastructure makes sense [and dollars]. Among the most useful, and user-friendly:

Click here for a list of alternative approaches to estimating the costs and benefits of green and grey infrastructure.

Types of Economic Analysis to Inform Policy Decisions

Capital Cost Assessment
  • Up-front costs: land, construction, materials
  • One-time expenses – not including O&M

Cost-Benefit Analysis
  • Comparison of financial or monetized benefits to costs [NPV lifecycle analysis if possible]
  • Quantified and monetized financial, environmental and social benefits [“triple bottom line”]
  • Qualitative description if necessary
Life-Cycle Cost and/or Benefit Component
  • Life-cycle costs over the life of the project, including installation, operations, replacement, maintenance, disposal, financing
  • Life-cycle benefits
  • Life-cycle net benefits
Cost-Effectiveness Analysis
  • Capital or life-cycle costs as measured over comparative and uniform time frame, for example the cost per pound of a specific pollutant removed
Fiscal Impact Analysis
  • Impact of development or land use change on costs and revenues of governmental units
Benefit Valuation
  • Quantification of benefits in non-monetary terms, e.g. number of increased visitor days, gallons of stormwater stored or infiltrated on site
  • Monetization of these benefits, e.g. avoided treatment costs
Quantitative Ranking Based on Self-Described Non-Monetized Benefits and External Costs
  • Qualitative description of benefits and costs
  • Ranking of benefits according to agreed-to scale, e.g. 1 to 5