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Title 7: Flood Zone

Chapter 7-1  Flood Zone
Chapter 7-2  Flood Hazard Reduction

Chapter 7-1  Flood Zone

7-1-1   Definitions.  Terms used in this chapter unless the context otherwise plainly requires, shall mean:

A.   Appeal - a request for a review of the finance officer interpretation of any provisions of this ordinance or a request for a variance.

B.  Area of Shallow Flooding – means a designated AO, AH, or VO zone on a community’s Flood Insurance Rate Map (FIRM) with a one percent chance or greater annual chance of flooding to an average depth of one to three feet where a clearly defined channel does not exist, where the path of flooding is unpredictable and where velocity flow may be evident.  Such flooding is characterized by ponding or sheet low. 

C.  Area of Special Flood Hazard - the land in the flood-plain within a community subject to a one percent or greater chance of flooding in any given year.

D.   Base Flood - the flood having a one percent chance of being equaled or exceeded in any given year.

E.  Basement – any area of the building having its floor sub-grade (below ground level) on all sides.

F.   Development - any man-made change to improved or unimproved real estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, excavation, or drilling operations or storage of equipment of materials located within the area of special flood hazard.

G.   Existing Manufactured Home Park or Subdivision - a manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including, at a minimum, the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads) is completed before July 1, 1990.

H.   Expansion to Existing Manufactured Home Park or Subdivision - the preparation of additional sites by the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including the installation of utilities, the construction of streets, and either final site grading or the pouring of concrete pads).

I.   Flood or Flooding - a general and temporary condition of partial or complete inundation of normally dry land areas from:
1)   The overflow of inland or tidal waters and/or
2)   The unusual and rapid accumulation or runoff of surface waters from any source.

J.   Flood Insurance Rate Map (FIRM) - the official map on which the Federal Emergency Management Agency has delineated both the areas of special flood hazards and the risk premium zones applicable to the community.

K.   Flood Insurance Study - the official report provided by the Federal Emergency Management Agency that includes flood profiles, the Flood Boundary-Floodway Map, and the water surface elevation of the base flood.

L.   Floodway - the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than one foot.

M.   Flood Zone Administrator – City Finance Officer

N.   Lowest Floor - the lowest floor of the lowest enclosed area (including basement).  An unfinished or flood resistant enclosure, usable solely for parking vehicles, building access or storage, in an area other than a basement area, is not considered a building's lowest floor, provided that such enclosure is not built so as to render the structure in violation of the applicable non-elevation design requirements of Section 60.3 of the National Flood Insurance Program regulations.

O.   Manufactured Home - a structure, transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without a permanent foundation when connected to the required utilities.  The term "manufactured home" does not include a "recreational vehicle".

P.   New Construction - structures for which the "start of construction" commenced on or after July 1, 1990.

Q.   New Manufactured Home Park or Subdivision - a manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed (including at a minimum, the installation of utilities, the construction of streets) and completed after July 1, 1990.

R.   Recreational vehicle - a vehicle which is (1) built on a single chassis; (2) 400 square feet or less when measured at the largest horizontal projections; (3) designed to be self-propelled or towable by a light duty truck; and (4) designed primarily not for use as a permanent dwelling but as temporary living quarters for recreational, camping, travel, or seasonal use.

S.   Start of Construction - the date the building permit was issued for new construction or for substantial improvements, provided the actual start of construction, repair, reconstruction,  placement, or other improvement was within 180 days of the permit date.  The actual start means the first placement of permanent construction of a structure on a site, such as the pouring of slab or footings, the installation of piles, the excavation or the placement of a manufactured home on a foundation.  Permanent construction does not include land preparation, such as clearing, grading, and filling; nor does it include the installation of streets and/or walkways; nor does it include excavation for a basement, footing, piers, or foundations or the erection of temporary forms; nor does it include the installation on the property of accessory buildings, such as garages or sheds not occupied as dwelling units or not part of the main structure.  For a substantial improvement, the actual start of construction means the first alteration of any wall, ceiling, floor, or other structural part of a building, whether or not that alteration affects the external dimensions of the building.

T.   Structure - a walled and roofed building, manufactured home, or gas or liquid storage tank that is principally above ground.

U.   Substantial Damage – damage of any origin sustained by a structure whereby the cost of restoring the structure to its before damaged condition would equal or exceed 50 percent of the market value of the structure before the damage occurred.

V. Substantial Improvement - any repair, reconstruction, or improvement of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure either:
1)   before the improvement or repair is started, or
2)   if the structure has been damaged and is being restored, before the damage occurred.  For the purpose of this definition, "substantial improvement" is considered to occur when the first alteration of any wall, ceiling, floor, or other structural part of the building commences, whether or not that alteration affects the external dimensions of the structure.

The term does not, however, include either:
1)   any project for improvement of the structure to comply with existing state or local  health, sanitary, or safety code specifications which are solely necessary to assure safe living conditions, or
2)   any alteration of a structure listed on the National Register of Historic Places or a  State Inventory of Historic Places.

W.   Variance - a grant of relief from the requirements of this ordinance which permits construction in a manner that would otherwise be prohibited by this ordinance.

X.  Violation – the failure of any structure or other development to be fully compliant with the community’s floodplain management regulations.  A structure or other development without an elevation certificate, other certificates, or other evidence of compliance required in Section 60.3 (b)(5), (c)(10), (d)(3), (e)(2), (e)(4) or (e)(5) is presumed to be in violation until such time as that documentation is provided.

7-1-2   Lands To Which Flood Zone Applies.  This title shall apply to all areas of special flood hazard within the jurisdiction of the City of Groton identified by the Federal Emergency Management Agency in a scientific and engineering report entitled, "The Flood Insurance Study" for the City of Groton dated March 18, 2008, with an accompanying Flood Insurance Rate Map (FIRM) (Panel number 46013C D Firm), is hereby adopted by reference and declared to be part of this ordinance.  The Flood Insurance Study and FIRM are on file at the City Finance Office, 209 N Main, Groton, South Dakota.

7-1-3   Development Permit.  A development permit shall be obtained before construction of development begins within any area of special flood hazard established in 7-1-2, application for a development permit shall be made on forms furnished by the Finance Officer and may include, but not be limited to:
Plans in duplicate drawn to scale showing the nature, location, dimensions, and elevations of the area in question; existing or proposed structures, fill, storage of materials, drainage facilities; and the location of the foregoing.  Specifically, the following information is required:

A.   Elevation in relation to mean sea level of the lowest floor (including basement) of all structures;

B.   Elevation in relation to mean sea level to which any structure has been floodproofed;

C.   Certification by a registered professional engineer or architect that the floodproofing methods for any non-residential structure meet floodproofing criteria in 7-2-5; and,

D.   Description of the extent to which any watercourse will be altered or relocated as a result of proposed development.

7-1-4   Application.  In the interpretation and application of this title, all provisions shall be:
A.   Considered as minimum requirements;

B.   Liberally construed in favor of the governing body;

C.   Deemed neither to limit nor repeal any other powers granted under State statutes.

D.   The degree of flood protection required by this ordinance is considered reasonable for regulatory purposes and is based on scientific and engineering considerations.  Larger floods can and will occur on rare occasions.  Flood heights may be increased by man-made or natural causes.  This ordinance does not imply that land outside the areas of special flood hazard or uses permitted within such areas will be free from flooding or flood damages.  This ordinance shall not create liability on the part of the City of Groton, any officer or employee thereof, or the Federal Emergency Management Agency for any flood damages that result from reliance on this ordinance or any administrative decision lawfully made thereunder.

E.   The finance officer is hereby appointed to administer and implement this ordinance by granting or denying development permit applications in accordance with its provisions.  Duties of the finance officer shall include, but not be limited to:

1.   Review all development permits to determine that the permit requirements of this ordinance have been satisfied;

2.   Review all development permits to determine that all necessary permits have been obtained from federal, state, or local governmental agencies from which prior approval is required.

3.   Review all development permits to determine if the proposed development is located in the floodway.  If located in the floodway, assure that the encroachment provisions of 7-2-7 A. are met.

4.   When base flood elevation data has not been provided, the finance officer shall obtain, review, and reasonably utilize any base flood elevation and floodway data available from any source and require that new construction, substantial improvements, or other development in Zone A are administered in accordance with 7-2-4, 7-2-5, & 7-2-6.

5.   Obtain and record the actual elevation (in relation to mean sea level) of the lowest floor (including basement) of all new or substantially improved structures, and whether or not the structure contains a basement.

6.   For all new or substantially improved floodproofed structures:

a.   Verify and record the actual elevation (in relation to mean sea level) to which the structure has been floodproofed.

b.   Maintain the floodproofing certificates required in 7-1-3 C.

7.   Maintain for public inspection all records pertaining to the provisions of this ordinance.

8.   Alteration of Watercourses:

a.   Notify adjacent communities and the South Dakota Department of Environment and Natural Resources prior to any alteration or relocation of a watercourse, and submit evidence of such notification to the Federal Emergency Management Agency.

b.   Require that maintenance is provided within the altered or relocated portion of said watercourse so that the flood-carrying capacity is not diminished.

9.  Interpretation of FIRM Boundaries, where needed, as to the exact location of the boundaries of the areas of special flood hazard (for example, where there appears to be a conflict between a mapped boundary and actual field conditions).  The person contesting the location of the boundary shall be given a reasonable opportunity to appeal the interpretation as provided in 7-1-4 F.

10.  Maintain the records of all appeal actions, including technical information, and report any variances to the Federal Emergency Management Agency.

F.   The Groton City Council, as established by the City of Groton, shall hear and decide appeals and requests for variances from the requirements of this ordinance.

1.   The Groton City Council shall hear and decide appeals when it is alleged there is an error in any requirement, decision, or determination made by the Finance Officer in the enforcement or administration of this ordinance.

2.   Those aggrieved by the decision of the Groton City Council, or any taxpayer, may appeal such decisions to the Brown County Circuit Court as provided in SDCL 1-26.

3.   In passing upon such applications, the Groton City Council shall consider all technical evaluations, all relevant factors, standards specified in other sections of this ordinance,  and:
a.   the danger that materials may be swept onto other lands to the injury of others;
b.   the danger of life and property due to flooding or erosion damage;
c.   the susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the individual owners;
d.   the importance of the services provided by the proposed facility to the community;
e.   the necessity to the facility of a waterfront location, where applicable
f.   the availability of alternative locations for the proposed use which are not subject to flooding or erosion damage;
g.   the compatibility of the proposed use with the existing and anticipated development;
h.   the relationship of the proposed use to the comprehensive plan and floodplain management program for hat area;
i.   the safety of access to the property in times of flood for ordinary and emergency vehicles;
j.   the expected heights, velocity, duration, rate of rise and sediment transport of the flood waters and the effects of wave action, if applicable, expected at the site; and
k.   the costs of providing governmental services during and after flood conditions, including maintenance and repair of public utilities and facilities such as sewer, gas, electrical, and water systems, streets and bridges.

4.   Upon consideration of these factors and the purposes of this ordinance, the Groton City Council may attach such conditions to the granting of variances as it deems necessary to further the purposes of this ordinance.

7-1-5   Variances.  Generally, variances may be issued for new construction and substantial improvements to be erected on a lot of one-half acre or less in size contiguous to and surrounded by lots with existing structures constructed below the base flood level, providing items 7-1-4 F.3.a.-k. have been fully considered.  As the lot size increases beyond the one-half acre, the technical justifications required for issuing the variance increases.  Variances may be issued for the reconstruction, rehabilitation or restoration of structures listed on the National Register of Historic Places or the State Inventory of Historic Places without regard to the procedures set forth in the remainder of this section.  Variances shall not be issued within any designated floodway if any increase in flood levels during the base flood discharge would result.  Variances shall only be issued upon a determination that the variance is the minimum necessary, considering the flood hazard, to afford relief.
Variances shall only be issued upon:

A.   a showing of good and sufficient cause;

B.   a determination that failure to grant the variance would result in exceptional hardship to the applicant; and

C.   a determination that the granting of a variance will not result in increased flood heights, additional threats to public safety, extraordinary  public expenses, create nuisances, cause fraud on or victimization of the public as identified in 7-1-4 F. 3. or conflict with existing local laws or ordinances.

Any applicant to whom a variance is granted shall be given written notice that the structure will be permitted to be built with a lowest floor below the base flood elevation and that the cost of flood insurance will be commensurate with the increased risk from the reduced lowest floor elevation.

Chapter 7-2 Flood Hazard Reduction 

7-2-1   Anchoring.  All new construction and substantial improvements shall be anchored to prevent floatation, collapse, or lateral movement of the structure and capable of resisting the hydrostatic and hydrodynamic loads.
All manufactured homes must be elevated and anchored to resist flotation, collapse, or lateral movement and capable of resisting the hydrostatic and hydrodynamic loads.  Methods of anchoring may include, but are not limited to use of over-the-top or frame ties to ground anchors.  This requirement is in addition to applicable state and local anchoring requirements for resisting wind forces.  Specific requirements may be:

A.   over-the-top ties be provided at each of the four corners of the manufactured home, with two additional ties per side at intermediate locations, with manufactured homes less than 50  feet long requiring one additional tie per side.

B.   frame ties be provided at each corner of the home with five additional ties per side at intermediate points, with manufactured homes less than 50 feet long requiring four additional ties per side;

C.   all components of the anchoring system be capable of carrying a force of 4,800 pounds; and

D.   any additions to the manufactured home be similarly anchored.

7-2-2   Construction Materials and Methods.  All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage; using methods and practices that minimize flood damage; with electrical, heating, ventilation, plumbing, and air-conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding.

7-2-3   Utilities.  All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the system.  New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the systems and discharge from the systems into flood waters.  On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.

7-2-4   Residential Construction.  New construction and substantial improvement of any residential structure shall have the lowest floor (including basement) elevated to or above the base flood elevation unless the properties have received a Letter of Map Amendment or Letter of Map revision and all FEMA regulations are complied with.

7-2-5   Nonresidential Construction.   New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor (including basement) elevated to one foot above the level of the base flood elevation; or, together with attendant utility and sanitary facilities, shall:  be floodproofed so that below the base flood elevation the structure is watertight with walls substantially impermeable to the passage of water;  have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy; and  be certified by a registered professional engineer or architect that the design and methods of construction are in accordance with accepted standards of practice for meeting the provisions of this paragraph.  Such certifications shall be provided to the official as set forth in 7-1-4 E. 6.  Properties that have received a Letter of Map Amendment or Letter of Map Revision based upon fill must comply with all FEMA regulations

7-2-6   Manufactured Homes.  Manufactured homes shall be anchored in accordance with 7-2-1.  All manufactured homes or those to be substantially improved shall conform to the following requirements:
A.   Require that manufactured homes that are placed or substantially improved on a site

1) outside of a manufactured home park or subdivision,

2) in a new manufactured home park or expansion to an existing manufactured home park or subdivision, or

3) in an existing manufactured home park or subdivision on which a manufactured home has incurred "substantial damage" as the result of a flood, be elevated on a permanent foundation such that the lowest floor of the manufactured home is elevated to or above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.

B.   Require that manufactured homes that are placed or substantially improved on sites in existing manufactured home parks or subdivision that are not subject to the provisions in (A) above be elevated so that either

1) the lowest floor of the manufactured home is at or above the base flood elevation, or

2) the manufactured home chassis is supported by reinforced piers or other foundation elements that are not less than 36 inches in height above grade and be securely anchored to an adequately anchored foundation system to resist floatation, collapse, and lateral movement.

7-2-7   Floodway.  Since the floodway is an extremely hazardous area due to the velocity of flood waters which carry debris, potential projectiles, and erosion potential, the following provisions apply:

A.   Prohibit encroachments, including fill, new construction, substantial improvements, and other development unless certification by a registered professional engineer or architect is provided demonstrating that encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge.

B.   If 7-2-7 A. is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of 7- 2.

7-2-8  Application of Building Codes to Foundation Drainage.  Drain tile shall be installed around the inside and outside of all concrete, masonry, or wood foundations of structures that retain earth and enclose habitable or useable spaces located below grade.  Drain tile shall be installed at or below the area to be protected and shall discharge by gravity or mechanical means into an approved drainage system to include a sump tank.  Washed pea rock shall extend at least 6 inches on both sides of the drain tile on both the inside and the outside of the foundation footing to include at least 6 inches of pea rock on the top and bottom of the drain tile.  The drain tile or “form a drain” shall be of an approved quality constructed for drainage purposes of at least 2½ inches in diameter and properly laid and connected to the sump tank.  The sump tank shall be at least 24 inches in diameter and shall extend at least 24 inches below the bottom of the basement floor and shall be capable of mechanical drainage to remove all accumulated water.  The drainage system shall be constructed in such a way as to discharge into an approved storm sewer system or to daylight.  Before any concrete basement floor is poured or the foundation backfilled, the drainage system shall be inspected by the appropriate city personnel.