The science is clear: protected forests make for cleaner water. However, there is less consensus about how to measure the impacts — information that is critical if our society is to allocate scarce funds to protect the forestland that counts.
For example, does 1,000 acres of forest located directly next to a stream provide the same value to water quality as the equivalent amount of forestland located upslope on a hill? What if the forest is located in the “headwaters” of the stream, where the stream begins to form? Or in a watershed that has only 30 percent forest cover versus one hovering closer to 70 percent?
In an effort to answer these and other questions, the Open Space Institute is digging deeper into the true value of forests to water quality through our “Land Protection Impact Assessment” project. The three-year study, supported by the William Penn Foundation, will blend computer modeling and stream monitoring to quantify the value and assess individual components of OSI’s land protection work in the Delaware Basin. The study has the potential to inform watershed protection initiatives elsewhere, including OSI’s budding effort in the Sebago watershed in Maine and the work of burgeoning water funds. See publication from May 2018.
While many government programs on water quality spend hundreds of millions of dollars to reduce pollutants after forests have been converted to impervious surface or farms, new information could help guide future spending. If we could better understand the value of forests in maintaining water quality, public agencies and private utilities might be more willing to pay to protect forests for drinking water — in the process saving taxpayers billions.