The Metropolitan Government of Nashville and Davidson County has enacted a Stormwater Management Ordinance in order to reduce the adverse impacts of stormwater runoff from development sites in Davidson County to the greatest extent possible, by establishing minimum requirements and procedures to control the quantity and quality of stormwater runoff associated with land development. The Metropolitan Government of Nashville and Davidson County is the permitting authority for all land disturbing activities and requires the land owner to maintain all on-site stormwater control facilities and all open space areas (e.g. parks or “green” areas) required by the approved stormwater control plan. The Metropolitan Government of Nashville and Davidson County will only provide construction permits to projects that establish a plan to manage stormwater runoff occurring during the construction process. Stormwater fees will be collected by The Metropolitan Government of Nashville and Davidson County. The Metropolitan Government of Nashville and Davidson County, under the NPDES program, also has the authority to inspect properties for noncompliance and can issue a notice of violation (NOV) for any deficiency or infraction onsite.
The Director of MWS, the Director of Codes Administration, or any of their duly authorized representatives may enter upon the premises of any land within Metropolitan Nashville and Davidson County for the purposes of inspecting the site before, during, and after construction to determine compliance with these regulations.
The Director of MWS or any of his or her duly authorized representatives may enter upon the premises of any land and enter facilities within Metropolitan Nashville and Davidson County for the purposes of inspecting potential impacts to stormwater quality or any activities that may violate the NPDES MS4 permit.
Care must be taken to ensure that any required detention facilities do not become nuisances or health hazards. Stormwater quality management practices generally require more maintenance than stormwater quantity management practices. Detention facilities should be designed to require minimal maintenance, and maintenance responsibility must be clearly stated on the plans. Detention facilities may be designed to serve multiple purposes whereby runoff may be detained under wet-weather conditions, but also serve as common or recreational areas during dry-weather conditions. Where multi-purpose facilities are provided, or where flat grades or poorly draining soils are encountered, provisions for adequate low flow stormwater management system may be required. Where the retention/ detention facility is planned to be used as a lake, pond or stormwater quality management practice with a permanent pool, water budget calculations shall be performed and submitted to demonstrate that an adequate pool is expected during dry summer months. More detailed specifications on detention structures can be found in Volume 4 Section 6.
All stormwater quantity and/or quality control SCMs must be maintained by the landowner or the homeowner’s association in perpetuity.
A Maintenance Document must be submitted with the Grading Permit application and must include the following:
The Maintenance Document must be recorded prior to final Grading Permit approval. If the final configuration of the stormwater system components or BMP differs from the original configuration proposed with the Grading Permit application, the Maintenance Document must be revised, finalized, and rerecorded. Failure to follow the Maintenance Document could result in enforcement action. Nothing in these regulations alters, amends, or negates requirements under existing detention pond agreements between the Metropolitan Government and property owners.
The long-term maintenance plan within the Maintenance Document contains the inspection priorities and schedule for the stormwater system components and SCMs. The SCM owner is responsible for inspecting the stormwater system, including SCMs, according to the schedule and annually submitting a completed report summarizing inspections and maintenance performed on
all SCMs associated with the grading permit. The report format and submittal process are described at: SCM.Nashville.gov. The Annual Inspection and Maintenance Summary Report for all
inspection and maintenance activities performed the previous calendar year should be submitted after January 1st, but no later than July 1st of each year.
Metro has established a post-construction stormwater quality program that applies a consistent standard for pollutant removal, regardless of the type of development. This chapter describes the post-construction stormwater quality program and requirements including:
• The targeted pollutant and pollutant reduction goal;
• Water quality treatment volume requirement for new development;
• Low Impact Development guidance;
• A listing of pre-approved structural Best Management Practices (BMPs);
• Testing requirements for proprietary BMPs; and
• Water quality treatment volume site design credits.
An automated calculator that can be used in developing the post-construction stormwater quality plan can be downloaded from Metro’s Stormwater website.
The site design shall provide, in combination or alone, management measures that are designed, built, and maintained to infiltrate, evapotranspire, harvest, and/or use, at a minimum, the
stormwater runoff generated at a site by the first inch of every rainfall event preceded by 72 hours of no measurable precipitation. A site designed in accordance with the Stormwater Management Manual, Volume 5, LID Manual, that meets the 80% runoff reduction goal contained therein is presumed compliant with this goal.
Each water quality SCM installed on a site requires maintenance so that it functions properly, ensuring that it helps fulfill the water quality goal for the site. Therefore, a SCM-specific Maintenance Document for each development site is required. Please see Section 6.7.1 or Appendix F for additional information.
A. Any violation of this chapter shall be punishable by a civil penalty in an amount not to exceed five hundred dollars; provided, however, that any violation of Section 15.64.205 shall be punishable by a civil penalty of not less than fifty dollars nor more than five thousand dollars.
For purposes of assessing civil penalties under this chapter, each day of violation shall constitute a separate violation.
B. In assessing a civil penalty, the following factors may be considered:
C. The department may also assess damages proximately caused by the violator to the municipality which may include any reasonable expenses incurred in investigating and/or enforcing violations of this part, or any other actual damages caused by the violation.
D. In addition to all other remedies provided by law, the metropolitan government shall have the right to injunctive relief for any violation of this chapter
Monthly charges for stormwater are based on the amount of impervious square footage. Impervious surfaces are those disturbed or hardened surface areas that either prevent or limit the natural entry of water into the soil. Roof tops, buildings, streets, parking lots, sidewalks, asphalt, concrete, other paving, driveways, compacted gravel, patios, and artificial turf are all examples of impervious surfaces. This type of hard-surface improvement reduces natural infiltration and increases the amount of stormwater that flows off your property and into the drainage systems, creeks and rivers of our city.
Nashville Stormwater BMP Manuals