Intro To The Green-Gray Assessment Guide

Green-Gray Assessment Guide

Developed by: World Resources Institute

Launched in 2019

Why Use the Tool

The Green-Gray Assessment guide allows stakeholders to value the costs and benefits of integrating green or natural infrastructure into water supply systems to improve performance. Building on the latest applications of this work in Latin America, this guide overviews the green-gray assessment’s three pre-assessment steps and six main steps and provides recommendations on how to present results. The guide can be used in conjunction with the Natural Infrastructure for Aquifer Recharge Financial Calculator, an Excel-based tool with a flexible financial model that estimates the private costs and benefits (including the return on investment) of natural infrastructure interventions designed to enhance aquifer recharge.

Recommended Tool

Gabriela Morales, Manager of Water Management and Urban Resilience, WRI México:

Input Data Required

Information on water supply system, watershed conditions, ecosystem valuation, and more


Quantification of the financial, social, and environmental benefits for incorporating green infrastructure as well as a stakeholder map and stakeholder engagement strategy

Past Use Cases

Green-gray assessments have been used throughout Lain America, including in Monterrey, Mexico; Rio de Janeiro, Brazil; and São Paulo, Brazil. Read more in the guide.

Additional Guidance:

Read an overview of the tool.