An ordinance amending Title 17 of the Metropolitan Code, zoning regulations, by amending Section 17.28.040 by limiting housing development in floodplains and floodways, all of which is more particularly described herein (Proposal No. 2004Z-009T).

WHEREAS, Substitute Ordinance BL2002-2021 was adopted by the Metropolitan Council and became effective on April 5, 2003;

WHEREAS, development within the floodplain may occur provided development does not jeopardize the long-term, environmental viability of rivers and creeks within Davidson County nor the Metropolitan Government of Nashville and Davidson County’s eligibility for federal or state-funded flood insurance or other forms of disaster relief.

NOW, THEREFORE, BE IT ENACTED BY THE COUNCIL OF THE METROPOLITAN GOVERNMENT OF NASHVILLE AND DAVIDSON COUNTY:

SECTION 1. By amending Section 17.28.040, subsections A, B, and F, “Floodplain/Floodway Development Standards”, by deleting the existing text and substituting as follows:

A. Preserved Floodplain. All development proposed on property that is not developed, as defined herein, encumbered by natural floodplain or floodway, as of April 5, 2003, shall leave a minimum of fifty percent of the natural floodplain area, including all of the floodway area, or all of the floodway area plus fifty feet on each side of the waterway, whichever is greater, undisturbed and in its original, natural state. The preserved floodplain shall be adjacent to the floodway or, as otherwise approved by the zoning administrator, or by the metropolitan planning commission if the property is the subject of a subdivision or rezoning application. The clearing of trees and brush within the undisturbed area shall be prohibited. For purposes of this subsection, a portion of a lot shall be deemed to be developed if a grading or building permit has been issued or, if a portion of the lot has been disturbed by grading or, if a portion of the lot is improved with any material that substantially reduces or prevents the infiltration of stormwater by the total horizontal area of the lot including, but not limited to, roofs, streets, sidewalks and parking lots paved with asphalt, concrete, compacted sand, compacted gravel or clay. Evidence that a portion of the property is developed shall include grading or building permits and/or aerial photographs. Absent grading or building permits, a lot shall not be deemed developed under this section if the use of the property was for agricultural activities.

B. Encroachments. Limited encroachments into the preserved natural floodplain may be authorized as a variance by the Stormwater Management Committee, as set forth in Section 15.64 of the Metropolitan Code of Laws. Such variances, if approved, shall be approved only to the minimum extent required by the circumstances creating the hardship, and only if the Committee finds that the encroachment reduces the flood danger or would improve and enhance the environmental quality of the affected floodplain section. Variances shall not be granted as of right, irrespective of whether the property owner or the property in question is otherwise eligible for such variance. Of the fifty percent of the natural floodplain area required to be preserved, variances shall not be approved for greater than twenty percent of this area. See Table 17.20.040.A for encroachment examples.

Table 17.28.040.A: Encroachment Examples

Total site acreage                            100 acres     45 acres     13 acres     3 acres

Amount of site containing
natural floodplain/floodway                   50 acres    10 acres       6 acres     3 acres

Amount of site that must be
designated as preserved natural            50% or        50% or        50% or     50% or
floodplain/floodway area                      25 acres      5 acres       3 acres    1.5 acres

Amount of site that can be
graded, manipulated, and                     50% or        50% or        50% or     50% or
developed                                         25 acres      5 acres       3 acres    1.5 acres

Maximum encroachment
permitted by a variance into                 20% or        20% or        20% or     20% or
preserved natural                               5 acres       1 acres       .60 acres   .30 acres
floodplain/floodway area

Remaining development land area
w/ maximum variance granted              80 acres     41 acres     10.6 acres   2.1 acres
w/out any variance granted                75 acres     40 acres      10 acres     1.5 acres

F. Residential Development. Residential development on property encumbered by natural floodplain or floodway as of April 5, 2003 shall comply with the following, except for the installation of streets and utilities where required by the planning commission to alleviate an undue hardship. This provision shall not apply to development where either a building permit has been issued, or a preliminary plat has been approved by the planning commission, as of the effective date of this ordinance.

1. Single or Two-Family Lots. After the fifty percent of the natural floodplain area has been preserved, the remaining fifty percent may be subdivided provided that each residential lot is equal to, or larger than (a) 30,000 square feet, or (b) the minimum lot area permitted by the base zoning district, whichever results in the largest lot. Any residential lot, or any portion of a residential lot, containing natural floodplain shall be designated as a "critical lot" and minimum finished floor elevations shall be established on the final plat of subdivision approved by the metropolitan planning commission and the department of water services. The determination of lot yield shall be based upon the gross land area divided by the minimum lot area of the base zoning district.

2. Cluster Lots. The cluster-lot option shall not be used within any proposed manipulated areas of the original natural floodplain.

3. Alternative Design Plan. Any development (including all phases) that proposes residential lots which deviate from the standards established in this subsection shall submit for metropolitan council approval, a planned unit development district or urban design overlay district application, as provided below in Chapter 17.36 and Article XIII of this title. Approval of any such application shall not increase the number of lots that would otherwise be permitted under subsection F.1 of this section. Prior to planning commission consideration of the development, the Stormwater Management Committee shall provide a written recommendation to the planning commission based on the proposed development complying with all of the following criteria:
i) The development does not jeopardize the long-term, environmental viability of rivers and creeks within Davidson County;
ii) The development does not jeopardize the Metropolitan Government of Nashville and Davidson County’s eligibility for federal or state-funded flood insurance or other forms of disaster relief;
iii) The development does not inhibit, prevent, constrain, restrict, or impede the design or construction of any greenway or park as shown on the adopted general plan; and,
iv) The development does not create or materially increase a flooding hazard to persons or other property located within the natural floodplain and/or floodway area.

SECTION 2. That this Ordinance shall take effect five (5) days from and after its passage and such change be published in a newspaper of general circulation, the welfare of The Metropolitan Government of Nashville and Davidson County requiring it.

Sponsored by: Feller Brown