Roswell, GA
File #: 09-1022    Version: 1 Name: Swaybranch Dr. dam repair
Type: General Item Status: Passed
File created: 11/25/2009 In control: Public Safety and Public Works Committee
On agenda: 12/8/2009 Final action: 12/8/2009
Title: Discussion of the recommended option to repair existing dams on the Swaybranch Drive property
Title
Discussion of the recommended option to repair existing dams on the Swaybranch Drive property
Body
Action Required:
Guidance
 
Description:
On December 7, 2009 Mayor and Council are expected to approve acceptance of the property donation along Swaybranch Dr. and Market Place. There are two dams that need to be repaired. Both dams retain ponds that provide detention and some water quality improvement for the respective developments. The culvert at Warsaw Rd. downstream of the study area is undersized for the existing flows and the road overtops in larger flooding events. A technical analysis and report was prepared by a consultant to evaluate the options for repair. (See attached Executive Summary.) Four options for rehabilitation were presented ranging from $142,000 to $385,000. Options 2 and 3 are the only ones that satisfy current standards for detention facilities.
 
It is proposed to develop plans and construct a pond satisfying Option 3, which provides the optimum mix of economy and environmental improvement. This option would involve removing the existing dams and constructing one large detention pond. It is the best option to reduce peak discharge rates downstream as well as provide some water quality benefits to receiving waters. The cost is estimated at $363,000. There is currently $117,627.69 available in CDBG funding. Staff proposes that the currently available funds be used for the design of Option 3. The additional funds needed could be allocated from future CDBG program year funding.
 
Option 4 is not recommended because this removes the water quality treatment that is being provided and removes the detention capability all together. Water quality will be negatively impacted and flooding downstream will worsen
 
Comments: