Water Quality

Earth is often called “The Water Planet” because oceans cover 71% of its surface. Of all the water on Earth, only 2.7% is fresh water—and of that, most is frozen in glaciers and ice caps. Less than one half of one percent of all of the world’s water is fresh water that’s actually available for living things to use. It’s no wonder that water quality is a constant concern, or that the negative impacts of stormwater have become such a big deal. Not only do impervious surfaces such as roads, parking lots, sidewalks, and rooftops add to the nonpoint source pollution problem by carrying contaminants directly into surface waters, they prevent stormwater from seeping into the ground where it can be filtered by soil and pollutant-absorbing plants.

Reducing imperviousness and maintaining wetlands, grasslands, and other vegetated areas helps buffer the effects of stormwater runoff. Plants, roots, soil, and leaf litter trap sediments, debris, and particulates that would otherwise make their way into waterways. Trees and other plants act as water filters by absorbing nutrients and other dissolved impurities through their roots and converting them into plant tissue, which helps maintain healthy aquatic ecosystems for wildlife, recreation, and aesthetic enjoyment. By most estimates, the nationwide value of these essential “ecosystem services” runs into billions of dollars a year.