City of Powder Springs - File #: PZ 24-026

Date	Ver.	Action By	Action	Result	Action Details	Meeting Details	Video
8/19/2024	1	City Council	approved	Pass	Action details	Meeting details	Not available
7/29/2024	1	Planning & Zoning Commission			Not available	Meeting details	Not available
7/11/2024	1	Planning & Zoning Commission			Not available	Meeting details	Not available

PZ 24-026

APPLICANT: Stanley Martin Homes.

FLOODPLAIN VARIANCE: To allow development activity related to grading and earth works in the floodplain.

LOCATION: 2820 Macedonia Road. Barrett at Macedonia MXU Project

ZONING: MXU

Staff Recommendation: Approval. Planning and Zoning: Approval.

BACKGROUND:

The subject site was annexed and rezoned from R-20, LRO and NRC in the County to MXU in the city; approved April 3, 2023The mixed-use development will feature the following:

• Single-family Detached Housing: 51 Units

• Single-family Attached Housing: 98 Units

• Multifamily Housing: 297 Units

• Retail: 11,000 square feet.

The applicants request a floodplain variance to cut and fill within the flood plain, as demonstrated in figure 4. Land disturbance within the floodplain is necessary to construct the referenced development as approved at zoning. The disturbance of the floodplain in the form of fill will be minimized to an area of 0.08 acres and will be offset by an area of cut as shown in the attached grading exhibit in figure 4.

Code Requirements

I. Sec. 10-32 (d) of the ordinance discusses the requirements for impact on the flood elevations. This is applicable for both 100-yr existing and 100-yr future floodplain.

d) Granting of the variance will not result in increased flood heights, additional threats to public safety, extraordinary public expense, or creation of a nuisance.

II. Sec 10-15 and 10-16 of the ordinance list additional requirements for engineering study and the prohibited conditions for changes to flow characteristics - depth and velocity of the waters, continuing maintenance. (Included in the Appendix of this report)

III. As-built No-Rise Study and Certification will document that the as-built development meets the requirements in the ordinance.

SURROUNDING AREA:

The subject site is located at the northwest quadrant of the intersection of Barrett Parkway and Macedonia Road. Nearby uses include residential subdivisions, institutional uses, large vacant tracts and a Walmart Super Center.

Figure 1. Vicinity Map, showing floodplain impact.

Figure 2. Site Plan

Figure 3. Subject area approximately encircled in red.

Figure 4. Proposed Cut and Fill Area.

ANALYSIS:

The application was reviewed against the following criteria:

1. Good and sufficient cause for the relief sought exists.

The applicant expressed that earthworks in the floodplain is necessary to develop the site as previously approved at rezoning. The variance is required to construct the development.

2. Failure to grant the variance would result in exceptional hardship.

To construct the development as zoned, this variance must be obtained. The applicant has expressed that the disturbance of the flood area is minimized, and that Without this variance, the development will become prohibitive to construct due to cost.

3. The variance is the least deviation from the standards of this article necessary to accomplish the objectives of the applicant and/or the minimum necessary to afford relief.

The floodplain impacts have been minimized and offset by mitigatory cut areas as shown in the attached grading exhibit. The disturbance of the floodplain in the form of fill will be minimized to an area of 0.08 acres and will be offset by an area of cut as shown in the attached grading exhibit in figure 4.

4. Granting of the variance will not result in increased flood heights, additional threats to public safety, extraordinary public expense, or creation of a nuisance.

The applicant expressed that granting of the variance will not result in increased flood heights, threats to public safety, extraordinary public expense, or creation of nuisance.

Approval is contingent upon meeting this criterion.

5. No variance shall be issued within any designated floodway that would cause any increase in flood levels during the base flood discharge.

According to the applicant, no FEMA floodplain or floodway is impacted; the only impacts are to Powder Springs future conditions floodplain. No increase in flood levels are modeled as a result of the activity associated with this variance.

Approval is contingent upon meeting this criterion.

STAFF RECOMMENDATION: Approval with the following condition:

1. The applicant shall demonstrate no net fill in the floodplain, no rise, and shall not encroach into the floodway.

2. The applicant shall agree to pay a fee up to $3000 for the additional floodplain engineering reviews conducted by Dewberry. Any overage above the initial $3000 for additional reviews will be invoiced separately; otherwise, any remaining funds will be refunded.

Appendix

Sec. 10-15. Engineering study.

(a) Required. An engineering study shall be required, as appropriate to the proposed development activities on the site, whenever a development is proposed that will disturb any land within a floodway, area of special flood hazard, or area of future-conditions flood hazard, except as may be specifically waived by this section.

(b) Exemption. The director of community development, after consulting with the director of public works, may waive the engineering study requirement for single-lot residential development on streams without established base flood elevations and floodways.

(c) Study components. Engineering studies shall at minimum include the following:

1. A description of the extent to which any watercourse or floodplain will be altered or relocated as a result of the proposed development;

2. A physical illustration on a preliminary plat, grading plan, or site plan, as appropriate, which shall clearly define all proposed encroachments; step-backwater analysis, using a FEMA-approved methodology approved by the director of public works;

3. Floodplain storage calculations based on cross-sections (at least one every 100') showing existing and proposed floodplain conditions and demonstrating that base flood floodplain and future-conditions floodplain storage capacity will not be diminished by the proposed development. Computations will be shown duplicating Flood Insurance Study results and will then be rerun with the proposed modifications to determine the new base flood profiles, and future-conditions flood profile.

(d) Submission, review, and approval. An engineering study required by this article shall be submitted to and is subject to approval of the director of public works prior to approval of any permit that would authorize the disturbance of land.

Sec. 10-16. General standards for encroachments.

(a) Prohibited conditions. No development shall be authorized, and no variance shall be granted within any area of special flood hazard or area of future-conditions flood hazard that could result in development or condition that:

1. Raises the base flood elevation or future-conditions flood elevation equal to or more than 0.01 foot;

2. Reduces the base flood or future-conditions flood storage capacity;

3. Changes the flow characteristics as to the depth and velocity of the waters of the base flood or future-conditions flood as they pass both the upstream and the downstream boundaries of the development area; or

4. Creates hazardous or erosion-producing velocities, or results in excessive sedimentation.

(b) Compensation for storage capacity. Compensation for storage capacity shall occur between the average ground water table elevation and the base flood elevation for the base flood, and between the average ground water table elevation and the future-condition flood elevation for the future-conditions flood, and lie either within the boundaries of ownership of the property being developed and shall be within the immediate vicinity of the location of the encroachment. Acceptable means of providing required compensation include lowering of natural ground elevations within the floodplain, or lowering of adjoining land areas to create additional floodplain storage. In no case shall any required compensation be provided via bottom storage or by excavating below the elevation of the natural (pre-development) stream channel unless such excavation results from the widening or relocation of the stream channel.

(c) Slope of cut areas. Cut areas shall be stabilized and graded to a slope of no less than 2.0%.

(d) Transitions. Effective transitions shall be provided such that flow velocities occurring on both upstream and downstream properties are not increased or decreased;

(e) Verification via engineering study. Verification of no-rise conditions (less than 0.01 foot), flood storage volumes, and flow characteristics shall be provided via a step-backwater analysis meeting the requirements of this article (see also section 10-15, "Engineering Study" of this article).

(f) Public utilities and facilities. Public utilities and facilities, such as water, sanitary sewer, gas, and electrical systems, shall be located and constructed to minimize or eliminate infiltration or contamination from flood waters; and

(g) Continuing maintenance. The property owner shall be responsible for continuing maintenance as may be needed within an altered or relocated portion of a floodplain on the property so that the flood-carrying or flood storage capacity is maintained. The City of Powder Springs may direct the property owner, at no cost to the City of Powder Springs, to restore the flood-carrying or flood storage capacity of the floodplain if the owner has not performed maintenance as required by the approved floodplain management plan on file with the city.

(h) Anchoring. New construction and substantial improvements, if authorized by variance, shall be anchored to prevent flotation, collapse and lateral movement of the structure. Manufactured homes, if permitted, shall be anchored to prevent flotation, collapse, and lateral movement. Methods of anchoring manufactured homes, if permitted may include, but are not limited to, use of over-the-top or frame ties to ground anchors. This standard shall be in addition to and consistent with applicable State requirements for resisting wind forces.

(i) Materials. New construction and substantial improvements, if authorized by variance, shall be constructed with materials and utility equipment resistant to flood damage;

(j) Methods of construction. New construction and substantial improvements, if authorized by variance, shall be constructed by methods and practices that minimize flood damage.

Sec. 10-32. General criteria for flood hazard area variances.

In lieu of criteria for the granting of variances generally, as provided in article 14 of this development code, a flood hazard area variance shall be issued only when it has been determined that the following criteria have been met:

(a) Good and sufficient cause for the relief sought exists;

(b) Failure to grant the variance would result in exceptional hardship;

(c) The variance is the least deviation from the standards of this article necessary to accomplish the objectives of the applicant and/or the minimum necessary to afford relief; and

(d) Granting of the variance will not result in increased flood heights, additional threats to public safety, extraordinary public expense, or creation of a nuisance.

(e) No variance shall be issued within any designated floodway that would cause any increase in flood levels during the base flood discharge.