Drainage Retention Areas (DRAs) require periodic mowing in order to keep them from becoming a nuisance. This maintenance program is funded solely by the Stormwater Program. Work is performed by contractors selected by competitive bid process. The mowing is performed on County-maintained ponds at a frequency of four times per year.

The drainage network along the County's roads requires constant care and maintenance in order to ensure an acceptable level of service for runoff treatment and quantity control. These projects represent a higher degree of maintenance work than the routine mowing and other minor repair work performed.

Sediment, litter and vegetative debris on County-maintained roads can be carried by stormwater runoff into drains and drainage retention areas (DRAs). Sediment, in particular, can clog storm drains and reduce the ability of DRAs to effectively manage stormwater and filter pollutants. When washed through storm drains, the undesirable substances can reach rivers, lakes and springs, contributing to pollution. 

The Stormwater Division oversees and fully funds a variety of major maintenance projects to restore the functionality of the DRA. Many of these involve the removal of dead trees, limbs, overgrowth and other debris in the DRA.

Marion County's karst geology is characterized by limestone in which erosion has produced fissures, sinkholes, underground streams and caverns. Although sinkholes develop as a result of erosion, their appearance can be triggered by factors such as heavy rain, drought, or excavation. Marion County Office of the County Engineer repairs sinkholes on County-maintained roads, rights-of-way and drainage retention areas (DRAs).