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A resolution requesting the Metropolitan Department of Water and Sewerage Services make revisions to the Stormwater Management Manual to address stormwater drainage across Nashville and Davidson County by updating the infill tree credit and including multi-family structures as residential infill.
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WHEREAS, as Nashville’s population continues to grow existing neighborhoods are experiencing additional development not envisioned by their original drainage systems; and
WHEREAS, continued development increases impervious surfaces and the volume of stormwater runoff which contributes to flooding, streambank erosion, and water quality degradation; and
WHEREAS, some installations of artificial turf are designed to route water rapidly away from sites instead of infiltrating the water into the ground like natural vegetation, increasing the flow of water from properties into Metro’s storm sewers and streams; and
WHEREAS, Metro Water has developed a policy to regulate turf installations to account for additional runoff; and
WHEREAS, mature trees reduce stormwater runoff which helps mitigate flooding and improves stream water quality; and
WHEREAS, mature trees provide many other benefits to our community including heat island mitigation, wildlife habitat, reduced air pollution, carbon sequestration, and increase property values; and
WHEREAS, residential infill projects have resulted in the loss of large canopy trees in neighborhoods and the existing tree credit for residential infill projects is rarely utilized; and
WHEREAS, Metro Water has developed a new infill tree credit for inclusion in the Metro Stormwater Management Manual (SWMM) that recognizes the ability of existing trees to reduce or eliminate the traditional stormwater control measures required for development which should also result in greater retention of urban canopy; and
WHEREAS, Metro Water established residential infill regulations in 2014 to help mitigate stormwater runoff from redevelopment in existing neighborhoods; and
WHEREAS, the regulated residential infill permitting is currently limited to individual or multiple single-family and two-family structures in the SWMM; and
WHEREAS, certain residential infill projects with three-family or more structures may create as much or more impervious area than individual or multiple single-family and two-family structures infill; and
WHEREAS, Metro Water should revise their SWMM to include multi-family structures as residential infill; and
WHEREAS, these revisions will help to mitigate flooding and stormwater runoff across Nashville and Davidson County.
NOW, THEREFORE, BE IT RESOLVED BY THE COUNCIL OF THE METROPOLITAN GOVERNMENT OF NASHVILLE AND DAVIDSON COUNTY:
Section 1. That the Metropolitan County Council hereby requests the Metropolitan Department of Water and Sewerage Services make revisions to the Stormwater Management Manual to address stormwater drainage across Nashville and Davidson County by updating the infill tree credit and including multi-family structures as residential infill.
Section 2. This Resolution shall take effect from and after its adoption, the welfare of The Metropolitan Government of Nashville and Davidson County requiring it.