NATURAL INFRASTRUCTURE

The document argues that integrating natural infrastructure—such as forests and wetlands—with built infrastructure can reduce water treatment costs and enhance water security. It provides a framework for 'green-gray analysis' to compare these options, discusses the scientific links between forest cover and water quality, and outlines various finance mechanisms and stakeholder engagement strategies to scale these efforts across the U.S.

• Natural infrastructure, including forests and wetlands, provides essential services such as water purification, flow regulation, and flood control, which can reduce or avoid the capital and variable costs of providing clean drinking water.
• A 'green-gray analysis' (GGA) methodology allows decision makers to compare the financial merits of natural infrastructure (green) against built infrastructure (gray) alternatives on a common platform.
• Forests are critical to the U.S. water supply, with approximately 53 percent of the freshwater supply in the contiguous United States originating in forests.
• Healthy forested landscapes promote water quality by anchoring soil against erosion, promoting infiltration, and minimizing overland flow and nutrient delivery to streams.
• The Conservation Priority Index (CPI) is a GIS-based tool used to objectively rank and prioritize land parcels based on their importance for providing watershed services, allowing for more cost-effective investment.
• Effective implementation of forestry best management practices (BMPs), such as maintaining forested buffers and improving road design, can reduce water quality impacts by 80 to over 99 percent.
• Current accounting standards set by the Governmental Accounting Standards Board (GASB) create a financial roadblock because they do not treat natural infrastructure as a capital asset, limiting a utility's ability to borrow money for its maintenance.
• Finance mechanisms for natural infrastructure include direct investments (rates, municipal bonds, state revolving funds), indirect investments (property tax incentives), voluntary donations, and market-based mechanisms (nutrient trading, carbon markets).
• Landowner participation in privately owned watersheds depends not only on financial incentives but also on program design that respects autonomy and incorporates local knowledge.
• Case studies demonstrate significant cost savings: New York City avoided an $8–$10 billion filtration plant by investing $1.5 billion in its watershed, and the City of Auburn, Maine, saved $30 million in capital costs by protecting 434 acres of land.

APA

GARTNER, T., MULLIGAN, J., SCHMIDT, R., & GUNN, J. (n.d.). NATURAL INFRASTRUCTURE. World Resources Institute. https://wriorg.s3.amazonaws.com/s3fs-public/wri13_report_4c_naturalinfrastructure_v2.pdf

Chicago

GARTNER, TODD, JAMES MULLIGAN, ROWAN SCHMIDT, and JOHN GUNN. NATURAL INFRASTRUCTURE. World Resources Institute, n.d. https://wriorg.s3.amazonaws.com/s3fs-public/wri13_report_4c_naturalinfrastructure_v2.pdf.

Wikipedia

{{cite report |last1=GARTNER |first1=TODD |last2=MULLIGAN |first2=JAMES |last3=SCHMIDT |first3=ROWAN |last4=GUNN |first4=JOHN |title=NATURAL INFRASTRUCTURE |publisher=World Resources Institute |url=https://wriorg.s3.amazonaws.com/s3fs-public/wri13_report_4c_naturalinfrastructure_v2.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{gartnerndnatural, author = {GARTNER, TODD and MULLIGAN, JAMES and SCHMIDT, ROWAN and GUNN, JOHN}, title = {{NATURAL INFRASTRUCTURE}}, institution = {World Resources Institute}, url = {https://wriorg.s3.amazonaws.com/s3fs-public/wri13_report_4c_naturalinfrastructure_v2.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }