(a) Purpose. The purpose of a Watercourse Protection Area is to promote the public health and safety by protecting surface and groundwater quality. By establishing a forested buffer along stream banks, the Watercourse Protection Area filters stormwater runoff before it reaches the waterway, provides high-quality stream habitats, reduces flood impacts, enhances environmental and community quality of life.
(b) Stream bank buffer and transition area. The filtering action of the Watercourse Protection Area will be accomplished by establishing two levels of buffering – the stream bank buffer and the transition area.
(1) The stream bank buffer is intended to protect and promote a forested corridor along protected watercourses. The buffer typically is a natural area that serves a host of ecological and aesthetic functions such as establishing root systems that reduce soil erosion, filtering stormwater pollutants from the waterway, and providing shade from mature trees, which is important to surface and water habitat. The stream bank buffer shall be 120 feet, as measured from the ordinary high-water mark, and shall apply to the following waterways: Alum Creek and Big Walnut Creek.
(2) The transition area is the outer level of filtering. It is also intended to protect the stream bank buffer from damage due to surface runoff from development and grade change. The transition area shall be 25 feet. Significant impervious surfaces, such as parking lots, are not permitted in the transition area. Other impervious surfaces should be kept to a maximum of 10 percent of the transition area. Impervious surfaces are any surface that cannot effectively absorb or infiltrate rainfall such as roads and streets, parking lots, roof tops, sidewalks and paved walkways.
(c) Vegetation: Plantings in the Watercourse Protection Area shall be native to the specific area of the development site and follow prescribed best management practices.