This data is compiled and analyzed every two-years/bi-annually. The percentage of rivers and streams fully supporting aquatic life has not changed significantly during the reporting period. In 80% of Vermont's rivers and streams, the aquatic organisms are considered healthy and support fishing uses. The remaining 20% are either impaired (due to pollution or altered flow/hydro dams that don't currently meet water quality standards) or the health of the aquatic biota is unknown. Over time, updated assessment data shows areas where we have been successful in river and stream restoration as well as areas where we have identified new impairments or alterations; making overall progress slow. Implementation of regulatory and voluntary measures is expected to help improve the water quality of our rivers and streams and their uses for fishing; however it is expected to take many years to show substantial progress.