All new construction in all districts shall be constructed at a reasonably safe elevation above the high water table in order to avoid water seepage problems and in order to provide adequate drainage from the structure to the SSTS.
A. Optimum Elevation For New Construction. The optimum elevation for new construction is six (6.0) feet above the level of the high water table as measured to the top of the lowest footing (= bottom of the lowest floor). Construction at or above six (6.0) feet above the high water table is strongly advised. The optimal elevation is shown in Illustration No. 4, Appendix A to Chapter 7A.
B. Acceptable Minimum Elevation For New Construction.
1. Except for accessory buildings, the acceptable minimum elevation for new construction is three (3.0) feet above the level of the high water table as measured to the top of the lowest footing (= bottom of the lowest floor), or two (2.0) feet above the designated or designed 100-year flood elevation, whichever is higher, unless evidence is submitted and certified by a geotechnical engineer, at the expense of the developer or property owner, that a lesser separation can be achieved and is warranted, and that evidence is verified by the City Engineer. Where any such geotechnical engineering report is based on piezometer data, the acceptable minimum elevation for new construction shall be four (4.0) feet above the level of the high water table, and said piezometers must be installed on each individual proposed lot for a minimum of twelve (12) months. Any construction below the optimum elevation of six (6.0) feet above the high water table shall require installation of: not less than one sump; one sump pump; and drain tiles either inside or outside all of the footings. The sump pump shall not be connected to the septic system in any manner. Caution: Although a three (3.0) foot minimum separation is acceptable under this Section, current FHA and VA construction standards require not less than four (4.0) feet minimum elevation as measured from the high water table to the top of the lowest footing. The three (3.0) feet minimum elevation required by this Section will meet or exceed the requirements of the Rice Creek Watershed District Regulations as of July 1, 1990. Coon Creek Watershed District and Sunrise River Watershed District do not have independent regulations for minimum construction elevations. The acceptable minimum elevation, sump, and drain tile are shown at Illustration No. 3, Appendix A to Chapter 7A.
2. Accessory buildings which have no need for an on-site sewage treatment system and which are constructed on a buildable area which is separate from the Buildable Area upon which the principal structure is built, are not required to have a sump, sump pump, or drain tiles if built at less than the optimum elevation. The acceptable minimum elevation for accessory buildings is two (2) feet above the high water table as measured to the top of the lowest footing.
3. Applicants may seek relief from strict application of Section 7A-803(B)(1) by filing an application for an administrative variance following the procedures and criteria of this subsection.
a. Criteria. Applicants may request an administrative variance from minimum floor elevation requirements provided that the property is zoned Rural Residential (RR) and the proposed construction meets all the following requirements:
i. The minimum elevation of new construction does not result in a minimum elevation less than 18” above mottled soil as determined by at least two soil borings in the immediate area of the proposed construction.
ii. The new construction is an addition to or expansion of an existing residential dwelling constructed before 1990; and
iii. The applicant agrees to install additional drain tile, as needed, and as approved by the City Engineer.
b. Review Procedures. The City Administrator and City Engineer will review administrative variance requests and the City Administrator will make a decision on the application. In order for an administrative variance to be approved, the following findings must be made:
i. Practical difficulties exist in complying with the requirements of Section 7A-803(B)(1) based on circumstances unique to the property which were not created by the applicant.
ii. The applicant proposes to use the property in a reasonable manner.
iii. Granting the variance is in harmony with the purpose and intent of the Zoning Ordinance and consistent with the City’s Comprehensive Plan.
iv. The variance, if granted, will not alter the essential character of the neighborhood or City.
c. Denial and appeals. If the City Administrator denies the request for an administrative variance, the City Administrator will provide a written notice to the applicant. Any aggrieve person may file an appeal of the decision of the City Administrator regarding an administrative variance application following the procedures as outlined in Section 4-104 of the City Code.
4. Fees. Administrative variances fees are set according to the City’s approved fee schedule.
C. Driveway Design Requirements. The City Council finds that it is in the public interest to adopt uniform driveway construction specifications. These uniform driveway specifications recognize that most sites for new construction in the City of Columbus will have a high water table lying relatively close to the native surface. It is the intent of the City Council to address public safety concerns by adopting uniform driveway specifications which should allow access to the buildable area by emergency services vehicles (police, fire, ambulance, etc.). It is the further intent of the City Council to address property value concerns by adopting high quality driveway specifications which should foster construction of durable and safe driveways, thereby protecting property values.
1. Driveway Required. Every buildable area shall be connected to a public road by a driveway which meets or exceeds the requirements of this City Code. A second buildable area on a lot, e.g., one used for construction of an accessory building, may be connected by a driveway to either the public right-of-way or to the first buildable area on the lot, and such driveway shall meet or exceed the minimum specifications of this Section.
2. If a commercial use and residential use share a common driveway, the driveway shall be constructed at the optimum width, not the minimum width, as shown in Illustration No. 5, Appendix “A” of this Chapter 7A.
3. Apron. Every driveway shall be connected to a public right-of-way by an apron which meets the design requirements shown at Illustration No. 4, Appendix “A” to this Chapter 7A. Driveway width and the variation in elevation between the road and the lot are factors which determine the length of the culvert which is required under the apron. Exact culvert requirements must be obtained from the City Public Works Department.
4. Buildable Area Contiguous with Front Setback. Where the buildable area is contiguous with the front setback, the driveway shall be constructed at a uniform grade from the elevation at the juncture with the apron to the elevation at the front setback.
5. Buildable Area Not Contiguous with Front Setback. Where the buildable area is not contiguous with the front setback, the driveway shall be constructed to meet or exceed the minimum specifications of this Section and of Illustration No. 5, Appendix “A” to this Chapter 7A. If the driveway is built at less than the optimum specifications, then the driveway shall include a “turn-around” area in front of the house or principal structure on the lot of not less than 24 feet by 24 feet, constructed and surfaced in the same manner as the driveway.
6. Subsurface Correction. The requirement to provide subsurface correction during driveway construction (removal of unsuitable material or placement of fabric mat) shall be determined by the City Engineer exercising professional judgment on a case by case basis.
7. Surfacing. If the elevation of the native soils prior to driveway construction is 3.0 feet or more above the high water table, and if the composition of the soils in the driveway area is free of organic soils, then sand or sand-unspecified gravel aggregate is required for surfacing. If the elevation of the native soils prior to driveway construction is less than 3.0 feet above the high water table, then bituminous, concrete or 4 inches of Class V aggregate surfacing is required.
8. Illustrations. The illustrations of aprons and driveways, Illustrations Nos. 4 and 5, Appendix “A” to this Chapter 7A, contain additional design requirements and specifications which are incorporated herein by reference. These Illustrations and their design requirements may be modified by City Council resolutions upon the advice of the City Engineer.
9. Inspections. Driveway construction shall be monitored and inspected by the Building Inspector. The Building Inspector shall have the discretion to call for additional elevation measurements, soil tests, or other on-site measurements as are necessary to ensure that driveways are constructed according to the standards established by this City Code. In difficult topography or soil conditions, the Building Inspector may consult directly with the City Engineer for professional assistance.
10. Variation from Strict Compliance. The City Engineer may exercise professional judgment and authorize some variation from strict compliance with these driveway design requirements for conditions found at the site, provided that the variations result in the construction of a driveway which meets the spirit and intent of this Section.
[§ 7A-803, formerly § 7A-818 and § 7A-819, amended by Ord. No. 89-15, effective December 29, 1989, Ord. No.. 90-3, effective March 23, 1990, Ord. No. 90-5, effective August 17, 1990, Ord. No. 91-2, effective June 12, 1992, and Ord. No. 02-01, effective May 17, 2002, amended by Ord. No. 07-02, effective March 1, 2007, amended by Ord. No. 16-03, effective February 4, 2016, amended by Ord. No. 18-01, effective May 31, 2018; amended by Ord. No. 21-09, effective December 8, 2021; amended by Ord. No. 23-03, effective June 8, 2023.]