How long does it take for a buffer to reach its maximum efficiency?

10-15 years.

Present research comparing the established buffers along Bear Creek with other native riparian plant communities suggests that chemical processing of nonpoint source (NPS) pollutants may take 10-15 years to reach maximum efficiency. This is mostly due to the time required for the perennial plant community to occupy the site and for soil quality parameters to reach optimum levels. Sediment trapping by the native grass component of the buffer may reach optimal efficiency in as little as five years.