Kingsport Regional Stormwater Detention Pond Removal Study
LOCATION: Kingsport, Tennessee
- Lee Gentry
CONSTRUCTION COST: $1.3 Million
- Flood Mitigation Study
- FEMA Data/Information
- Field Assessments
- HEC-HMS Watershed Model
- SWMM Model of Existing Structures
- TDEC, USACE, TVA Regulated Waterway
A Wal-mart Supercenter is located on West Stone Drive in Kingsport, Tennessee. The complex consists of the Wal-mart store and parking lot, a gas station, and a large stormwater detention pond. Adjacent facilities include restaurants, a farm supply company, and a home improvement store. The City of Kingsport desired to remove the detention pond if feasible, in order to make the prime property available for use.
The complex was constructed on previously undeveloped property, and the stormwater detention pond was constructed to reduce the rate of runoff from the site to decrease flooding and erosion downstream after the development was constructed. Removal of the pond would eliminate this control and could cause increased flooding and erosion. LDA was retained to investigate the technical issues associated with the removal of the pond, identify what measures would need to be taken to mitigate any adverse effects caused by removing the pond, and to develop an estimated cost for removal.
LDA researched and collected available GIS, ortho-photography, and FEMA information, as well as conducted a field assessment to determine existing conditions and identify potential issues associated with removing the pond. A HEC-HMS hydrology model was developed for the watershed to estimate peak flows entering into the storm drainage system. The drainage system hydraulics were modeled using SWMM. The models were then used to determine what modifications would be required to mitigate any adverse effects caused by removing the pond.
LDA also evaluated the effects on increased flood levels the pond removal would have on the receiving stream, the Holston River (a FEMA-regulated stream). Using FEMA model data, a rating curve was developed at the drainageway discharge, and the increase in flood elevation was determined. The results of the study were presented in a comprehensive written report presented to the client.