A buffer ordinance requires that a landscaped setback be created or preserved adjacent to waterways, in order to intercept, reduce and naturally attenuate stormwater runoff before it reaches the waterway.
Intercepting stormwater runoff before it reaches a stream can reduce pollution by attenuating pollutant loads through plant uptake or by chemical processes after infiltration into soils. If vegetated, the buffer strip can also reduce runoff flow and discharge rates, reducing flood risks (since runoff discharge to the stream will be slowed by vegetation and part will be converted to groundwater baseflow, contributing to the stream long after a storm event has passed, instead of at the storm peak).
Riparian buffers may be politically unpopular since riparian land is usually expensive because proximity to water is often deemed to be a development amenity. Despite the benefits of protecting an adjacent water resource, landowners may not want to give up being able to build on a part of their valuable waterfront property as a condition of development approval.
Example 1: Howard County, Indiana
Description: Howard County’s Zoning Ordinance has special provisions for riparian protection. The document is a pdf of the zoning code. The riparian related overlay is on page 3-6.
Example 2: Washtenaw County, Michigan
Description: Salem Township has a Riparian Area Protection Overlay Zone ordinance that went into effect in 2007.
Example 3: Centre County, Pennsylvania
Description: The Township has a Riparian Buffer Overlay Zoning District. The link leads to the page on the township’s website for the ordinance. The text can be found through a link at the bottom of the page.