A new report says that investments in forest conservation can save money in the provision of clean water – by treating water at up to one-seventh of the cost per thousand gallons of conventional wastewater treatment systems.

Forests for Water: Exploring Payments for Watershed Services in the U.S. South, published by the World Resources Institute (WRI), examines the potential for saving money by protecting upstream forests instead of building new, often costly water treatment infrastructure.

The issue brief provides an overview of how businesses and water utilities in the United States and Latin America are pursuing upstream forest conservation as a cost-effective means of ensuring clean water supplies.

The Report says that forests are often overlooked for the freshwater benefits they provide, but two-thirds of the United States’ water originates from forested lands. The water comes from precipitation that is filtered through forests, and much of it ends up in streams. In addition to filtering and purifying water, forests naturally regulate the timing and amount of water flows, which helps lessen flooding during heavy rainstorms. Forests also help curb erosion and prevent excess nutrients from fertilizer from entering nearby bodies of water.

New York saved billions of dollars on treatment costs

By naturally filtering water, the Report says that forests can reduce drinking water treatment costs. New York City saved billions of dollars in water filtration costs by conserving the forests and natural landscapes of the Catskills instead of paying for a new water filtration system.

By curbing erosion, forests can keep sediment and excess nutrients out of waterways. For instance forest buffers near streams can prevent nitrogen from entering waterways at approximately one-third of the cost per pound of nitrogen relative to wastewater treatment plant upgrades.

By filtering water through its porous soils, a forest can minimize wastewater treatment costs. According to the US Army Corps of Engineers a forest or forested wetland can filter water at approximately one-seventh of the cost per thousand gallons than can conventional wastewater treatment systems.

Green infrastructure can be less expensive than gray infrastructure

The report examines the business case for conserving forests for clean water and sets out proposals to use “payments for watershed services” which provide landowners with financial incentives to conserve, sustainably manage, and/or restore forests for one or more of the kinds of watershed services mentioned above. Such payments typically involve downstream beneficiaries paying upstream forest owners or forest managers.

There are three general types of payments for watershed services that companies and governments could take advantage of to cut costs:

• voluntary payments to upstream landowners to reduce the cost of doing business;
• payments to minimize the cost of meeting a regulation; and
• payments made to generate public benefits like improved water quality.

The Report says that many payments for watershed services share a common trait: they are investments in “green infrastructure” instead of “gray infrastructure.” i.e. investments in forests and natural open space instead of in human-engineered solutions to address water quantity or quality problems.