The boundaries and designations of the slope development district are hereby established and approved as defined herein and as shown and designated on the official zoning maps of the City of Huntsville, Alabama.

65.1.1. The slope development district boundary has been established at the elevation contour immediately above or below which a 25-foot vertical span of mountainside has a slope of 15 percent or greater and the district is to include those contiguous parts of mountains or hills that exhibit at least 100 feet of relief as measured from the lowest elevation contour that bounds the 15 percent or greater slope to the highest contour of the district as defined herein. In addition, the upper boundary shall be extended 50 feet (horizontal distance) beyond the elevation contour immediately below which a 25-foot vertical span exhibits a slope of 15 percent or greater.

65.1.2. When a lot is divided by the Slope Development District boundary line, the lot shall be considered as lying wholly within the district unless it satisfies the following conditions:

(1)

That portion of the lot lying within the slope development district shall remain undisturbed and shall have a restriction placed on the final plat requiring that it be retained in its natural state except for hiking trails, and

(2)

That portion of the lot lying outside the slope development district shall be of sufficient size and shape to meet all the minimum yard setback, lot area, and lot width requirements of the underlying zoning district.

If the option is taken to remove a divided lot from the authority of the slope development district regulations, then no part of the divided lot shall be included in the impervious cover calculations for the subdivision of which it is a part.

65.1.3. The slope development district boundary is shown and designated on a 1:4800 scale map (one inch equals 400 feet) having contour intervals of five feet. Slope percentage is calculated perpendicular to contours over a 25-foot vertical span. The boundary is delineated perpendicular to slope on the five-foot contour lines and parallel to slope between contour lines. Local variations in slope that continue for horizontal distances of less than 200 feet parallel to contour lines are not shown by adjustments in the district boundary.

65.1.4. In the event of a discrepancy between the mapped district boundary and the surveyed district boundary, the surveyed boundary line shall prevail, provided the following certification is made part of the slope map submitted for development approval:

I, ___________, do hereby certify that I am a licensed land surveyor in Huntsville, Alabama, that I have surveyed the lands embraced within (development name), that the contours shown hereon accurately describe the natural, undisturbed topography of the site existing prior to the development, and that the boundaries of the slope development district as shown hereon have been established in conformance with the provisions of section 65.1.1 of the Huntsville Zoning Ordinance.

(Ord. No. 96-159, 4-25-1996)

The slope development district is created as a special zoning classification to be superimposed on other existing zoning districts contained in the zoning ordinance of the City of Huntsville. Except where in conflict with the specific requirements of the slope development district, the permitted and accessory uses and all other requirements shall be as determined by the regulations of the basic underlying district contained elsewhere. All requirements for the slope development district, where superimposed on other existing zoning districts otherwise contained in the zoning ordinance of the City of Huntsville, shall be uniform for each class or kind of building, structure or improvement throughout the slope development district.

(Ord. No. 96-159, 4-25-1996)

The slope development district is hereby divided into two slope zones based on the increasing risk of instability and the decreasing safety factor associated with increasing slope as established by the Slope Development Study, Huntsville, Alabama, prepared by Ground Engineering and Testing Service, Inc., 1989. The zones are defined as follows:

65.3.1. Lower slope zone. This zone shall include all areas of land within the boundaries of the slope development district that are not part of the upper slope zone.

65.3.2. Upper slope zone. This zone shall include all areas of land within the boundaries of the slope development district beginning at the elevation contour defining the start of the 20 percent slope and encompassing all contiguous slopes of 20 percent or greater. The upper slope zone boundary shall be computed according to the procedure described in section 65.1.3 herein, where a 25-foot vertical span of mountainside has a slope of 20 percent or greater. The upper slope zone may begin at the lower district boundary, may extend to the upper district boundary if present, or may create one or more enclosed areas delineated by a continuous extension of the upper slope zone boundary.

65.3.3. If a lot is cut by the boundary contour separating the lower and upper slope zones, then the lot shall be considered to be a part of that slope zone in which the majority of its area is located.

65.3.4. Hazard zone. This zone shall include all areas of land within the boundaries of the Slope Development District that exhibit any or all of the following geologic or man-made hazards:

(1)

Pennington, shaley Upper Bangor, or Pride Mountain geologic formations;

(2)

Colluvial deposits having a depth of five feet or greater or being contiguous to an off-site colluvial deposit that exceeds five feet in depth; and

(3)

Evidence of mining operations (mine or quarry tailings, or similar geologic conditions).

65.3.5. For colluvial deposits present on a site to be removed from the hazard zone provisions, the following certification must be made a part of the site assessment map:

I, ___________, the geotechnical engineer of record, having caused investigations to be performed and based on the findings of said investigations, do hereby certify that the colluvial deposits identified by location and extent on this map are less than five feet in depth and are not contiguous to any off-site colluvial deposit that exceeds five feet in depth.

65.3.6. No buildings, structures or improvements shall be constructed, erected or placed on any land having a hazard zone designation, except where:

(1)

Such site has undergone additional geotechnical analysis and testing both upslope to where a potential landslide would begin and downslope to where a potential landslide would end, and

(2)

The engineer of record places the following signed certification on the final subdivision plat or, in the case of a multifamily development, on the site plan:

I, ___________ the engineer of record, certify that the proposed development shown hereon is designed in accordance with sound engineering standards and practices, and in accordance with all applicable development regulations. I further certify that I have caused prudent investigation, testing and inspections to be performed on all lands within the proposed development identified as hazard zone, as defined by the zoning ordinance of the City of Huntsville, Alabama, including geotechnical analysis and testing on all hazard zone lands and on lands upslope and downslope of the proposed development, and I have instructed the land surveyor as to those areas within the proposed development that fall within the hazard zone for inclusion in the development plats. Based upon the investigation, testing and inspections performed, as defined and discussed in the geotechnical analysis and report dated ________ and submitted in connection herewith, and further based upon any remedial measures taken in connection with the hazards defined therein, I certify that, within acceptable geotechnical standards, development of the property as shown on the plat will not diminish the stability of the slope or otherwise increase the likelihood of landslide or other slope failure and that the buildable areas designated hereon can meet a minimum safety factor of 1.5 for stability.

(3)

The owner of the property places the following signed certification on the final subdivision plat or, in the case of a multifamily development, on the site plan:

I, ___________, owner/owners of the lands embraced hereon, hereby certify that I have caused investigation in accordance with sound engineering standards and practice to be made of hazard zone lands, as defined by the zoning ordinance of the City of Huntsville, Alabama, within the development as shown hereon. I further understand the potential and inherent danger of said lands and that landslides have originated in conditions that regularly exist on said hazard zone lands.

With this knowledge, I hereby certify that I have caused all prudent measures to be taken in the design of the development as shown hereon, including an analysis of all lands upslope and downslope of the hazard zone lands, to assure that the site is safe for the proposed development, and within acceptable geotechnical standards the proposed development will not diminish the stability of the slope or otherwise increase the likelihood of landslide or other slope failure.

65.3.7. Where a subdivision or multifamily site contains unbuildable hazard zone land, then such land may be included in lots if:

(1)

The specific hazard zone condition is identified and its extent is designated on the final plat or site plan;

(2)

The area of the hazard zone land is restricted to remain undisturbed and be retained in its natural state;

(3)

The area of the hazard zone land is so located that the lot or site can be developed without disruption to it; and

(4)

A restricted use buffer extends a minimum of 25 feet beyond the edge of the hazard zone land.

(Ord. No. 96-159, 4-25-1996)

Within the boundaries of the slope development district, the following density requirements shall apply:

_____

65.4.1.

* See section 65.5.3.

_____

65.4.2. Application of impervious cover. Impervious cover is the sum of the areas within the boundary of a site that is covered with a surface material or treatment that substantially prohibits or impedes the infiltration of water into the ground. Maximum impervious cover for a lot or subdivision shall not exceed the number of square feet derived by multiplying the land area of such lot or subdivision by the appropriate impervious cover percentage. In addition to other impervious cover, all driveways and prepared parking areas shall be counted as impervious cover as shall all area lying below the roof of any structure. Impervious cover is not transferrable from one lot to another.

65.4.3. Nonresidential uses. Where a nonresidential use adjoins a residential use, a buffer at least 30 feet wide must be maintained in a natural state along such residential boundary.

65.4.4. Height limitations. The maximum number of stories for single-family residential buildings is 2½ and building height shall not exceed 45 feet at any point as measured vertically from the natural grade prior to development to the highest point of the roof.

Building height for multifamily and nonresidential buildings shall not exceed 35 feet as measured vertically from the natural grade prior to development to the highest point of the roof. If roof-mounted mechanical or other equipment is present, such equipment shall be located or screened so as to not be visible from adjacent streets and properties; any such screening shall meet the applicable height limitation.

Chimneys and antennae shall be excluded from the above height limitations.

65.4.5. Buildable area. Where there is any proposed multifamily construction or any subdivision of land within the slope development district, a building site plan or final plat is required. The final plat or building site plan shall include:

(1)

A clear delineation of the buildable area for each lot or building site. The buildable area shall satisfy all density requirements of the zoning ordinance as well as those regulations requiring setbacks from cultural and environmental features and from identified hazards.

(2)

The buildable area shall be large enough to permit the use of the allotted amount of building area for the lot and be free of slopes in excess of 35 percent and of all hazard zone conditions unless accompanied by certifications as specified in section 65.3.6. If the buildable area contains slopes between 25 percent and 35 percent, the plat must state that foundation restrictions apply.

(3)

A clear designation of the maximum amount of impervious cover in square feet allotted to each lot.

(4)

A clear designation of the maximum amount of building area in square feet allotted to each buildable area.

(5)

A clear designation of the minimum area of each lot, expressed in square feet, that must be retained in its natural state.

65.4.6. Off-street parking requirements. Two off-street parking spaces shall be provided for each residential unit.

Nonresidential parking spaces shall be as required by section 70.1, off-street parking.

65.4.7. Permanent reservation of land. Development within the slope development district is eligible for modified density controls when the following conditions are satisfied:

(1)

At least 15 percent of the total area of the subdivision tract lying within the slope development district is permanently set aside prior to development to be held in its natural, undisturbed state except for hiking trails; and

(2)

The land so restricted is the steepest, or the most hazardous, or the most environmentally sensitive portion of the tract, so that the land remaining for development is that most suitable and safest for development.

The unreserved portion of the tract lying within the lower slope zone may be developed according to the following density controls:

(Ord. No. 96-159, 4-25-1996)

65.5.1. Grading.

(1)

Natural slopes in excess of 35 percent shall not be graded except as needed to provide for utility service to developable areas of less than 35 percent slope and/or other officially adopted public facilities except that in no case shall any building or structure be allowed.

(2)

Grading on natural slopes of 25 percent or greater shall only be permitted for the construction and installation of roads, utilities, and other limited foundation grading, which can be shown to be sensitive to the existing terrain. Proposed structures on slopes of 25 percent to 35 percent shall be designed to conform to the terrain and shall utilize pier and beam, step, or other such foundations that require only limited excavation and filling. Areas of cut visible from any public right-of-way shall be screened by landscaping except in those cases where visible cuts in stable rock are impractical to screen.

(3)

No cut and no fill shall be allowed on any lot except for:

(a)

The construction of a primary use structure when the cut or fill is required for the construction of the building foundation, in which case the total area of such cut or fill, as measured from the exterior faces of the walls of the structure to the outer limits of the cut or fill, must be subtracted from the allotted amount of landscaped yard area as defined in section 65.5.3;

(b)

The construction of a driveway or parking area to access the primary use structure, in which case the total area of such cut or fill, as measured from the outer edges of the driveway or parking area to the outer limits of the cut or fill, must be subtracted from the allotted amount of landscaped yard area as defined in section 65.5.3;

(c)

The construction of utilities, provided all said areas of cut are restored to natural grade and revegetated to conform to the character of the surrounding natural terrain. In order to reduce grading disturbance during utility installation, all utilities shall be incorporated in common trenches, where practical, utilizing duct banks designed and constructed to current standards of Huntsville Utilities as the same may from time to time be amended; or

(d)

The testing of land, as required by the regulations of the City of Huntsville, or other bona fide geotechnical or geological testing provided that a testing plan consistent with the provisions of the subdivision regulations of the City of Huntsville is submitted to and approved by the zoning administrator prior to any cut or fill operation.

(4)

Mass grading of hilltops, ridges, and ravines shall be prohibited.

(5)

All slopes to be stabilized shall conform to the surrounding natural terrain and shall be revegetated so as to conform to the natural character of the surrounding area.

65.5.2. Environmental features.

(1)

Road alignment shall follow natural terrain wherever possible and no unnecessary cuts or fills shall be allowed for the sole purpose of creating additional lots or building sites.

(2)

A restricted use area shall extend a minimum of 50 feet from the following features:

(a)

Landslides. Setback measured from mapped boundary of landslide.

(b)

Perennial streams and major drainageways including, but not limited to, all streams and drainageways delineated by the U.S. Geological Survey and Tennessee Valley Authority on the 7.5 minute quadrangle topographic map series. Drainageways that have been modified by man or by natural processes so that they are different from those delineated on the 7.5 minute quadrangle maps shall be set back from as defined herein. In addition, some man-made drainageways as designated by the city engineer shall be set back from as defined herein.

The 50-foot setbacks shall extend landward from the banks or normal high water points of the drainageways.

(c)

Bluffs of greater than 20 feet of relief. Setbacks shall extend from a line defining the top and bottom of said bluff.

(3)

A restricted use area shall extend a minimum of 25 feet from the following features:

(a)

Cave entrances. Setback measured from edge of cave entrance.

(b)

Sinkholes. Setback measured from edge of those sinkholes that exhibit three feet or greater depth of closed depression.

(c)

Perennial springs. Setback measured from perimeter of spring.

(d)

Abandoned quarries. Setbacks shall extend from the top and bottom of quarry face.

(e)

Historical and archeological sites. Setbacks shall extend from the boundaries of significant historical or archeological sites as determined by the Alabama Historical Commission.

(f)

Wetlands. Setbacks shall extend from the boundary of the wetland.

(4)

Areas within the above minimum setbacks shall be retained in their existing state and be restricted from all development except for hiking trails, provided such trails neither create nor increase a public hazard, and except for certain minimal grading within said setback, provided the following conditions are met:

(a)

Minimal grading is required to construct public utility service and/or roadways to adjacent properties; and

(b)

No technically feasible alternative route or construction method exists.

(5)

The site shall be suitable for development in the manner proposed, without hazards to persons or property on or off the tract, from probability of flooding, erosions, subsidence or slipping of the soil, or other geologic dangers. Condition of soil, ground water level, drainage, and topography shall be appropriate to both kind and pattern of such intended development.

(6)

The natural terrain shall not be disturbed, cut, filled, graded or rearranged by either the developer or subsequent property owners beyond that necessary for the construction of buildings and infrastructure to the extent herein permitted.

65.5.3. Landscaping. It is desirable that yards be maintained in a condition close to their natural state in order to reduce the potential negative impacts of stormwater runoff, erosion and sedimentation, chemical fertilizer pollution, and irrigation that are commonly associated with the establishment of lawns and other plantings not native to the mountain slopes; however, a landscaped yard may be created provided the following conditions are met:

(1)

In the lower slope zone, 70 percent of the lot shall be retained in its natural state.

(2)

In the upper slope zone, 80 percent of the lot shall be retained in its natural state unless the lot lies on a slope of 25 percent or greater, in which case the entire lot beyond the allotment for impervious cover shall be retained in its natural state.

(3)

Land lying within utility and drainage easements that is disrupted by installation or maintenance of public improvements shall not be counted as disturbed lot area for the purpose of section 65.5.3.

(4)

Natural state shall mean the original condition of the land prior to any development or other human disturbance. No grading, excavating, or filling and no construction of roads, driveways, parking areas or structures shall be allowed. No tree cutting shall be allowed except for sick or damaged trees or trees that create a health or safety hazard. Unpaved hiking trails may be permitted as may additional plantings of native trees, shrubs and wildflowers that would be compatible with and enhance the natural environment.

(5)

The allotted area of landscaped yard must be decreased by the amount of any areas of cut or fill utilized in construction of the primary use structure and/or driveway/parking areas that have not been finished with impervious cover or returned to their natural state through revegetation that conforms to the character of the surrounding natural terrain.

(6)

The majority of the landscaped area should be located on that portion of the lot which is upslope from the primary use structure in order to minimize the harmful effects of increased pollution, runoff and erosion on downslope properties.

(7)

Fill material that is imported to provide a base for landscape plantings shall be limited to the minimum amount necessary and no colluvial soil shall be used for fill.

(8)

Turf grass and other imported ground covers shall not be planted on colluvial soil.

(9)

Trees may be removed:

(a)

Within rights-of-way to allow road construction;

(b)

Along easements if necessary for construction of said utility;

(c)

As necessary to conduct geotechnical testing after approval of the testing plan by the zoning administrator.

(d)

Within the areas of cut or fill required for construction of primary use structures, driveways and parking areas;

(e)

On that portion of a lot not required to be maintained in its natural state; and

(f)

To eliminate sick or damaged trees or trees that create a health or safety hazard.

(10)

Tree topping and clear cutting are prohibited within the slope development district.

(Ord. No. 96-159, 4-25-1996; Ord. No. 07-460, § 5, 6-28-2007)

65.6.1. Lots of record. Where a lot, as defined in section 3.1, exists wholly within the slope development district or its buildable area is cut by the slope development district boundary and it was recorded in the office of the probate judge in the county where said lot is situated prior to the time of adoption of this article, then such lot is excluded from the regulations of this article, except for:

(1)

Building heights for all single-family residential lots of record shall not exceed more than 45 feet at any point as measured vertically from the natural grade prior to development to the highest point of the roof. The number of stories permitted shall not exceed 2½ stories.

Building heights for all multifamily and nonresidential lots of record shall not exceed 35 feet (35') at any point as measured vertically from the natural grade prior to development to the highest point of the roof.

(2)

Certification to the manager of inspection prior to the issuance of a building permit that the proposed building site and structure can meet a minimum safety factor of 1.5 for stability;

(3)

Certification to the manager of inspection prior to the issuance of a building permit that the proposed site can meet a minimum safety factor of 3.0 for bearing capacity of the underlying soil; and

(4)

Certification to the manager of inspection prior to the issuance of a certificate of occupancy that the completed building or structure meets a minimum safety factor of 1.5.

65.6.2. Existing structures. Where a lawful structure exists within the slope development district or has been issued a building permit by the manager of inspection prior to the date of adoption of this article, then such structure is excluded from the regulations of this article except when an addition is undertaken that would enlarge the footprint of the existing structure. In such case, the manager of inspection may require certifications as defined in section 65.6.1 above.

(Ord. No. 96-159, 4-25-1996)

Applications for variances and special exceptions from the requirements of this article shall be submitted to the city zoning administrator, who shall forward such application to the city engineer, who shall review the application and report his findings to the zoning administrator for a decision. An appeal of the zoning administrator's decision may be filed with the board of zoning adjustment as provided in article 92 of the zoning ordinance of the City of Huntsville. Variances shall only be issued upon a determination that an unnecessary hardship exists on the subject property, unique or different from that shared or suffered by adjacent or similarly situated property within the slope development district, or as otherwise permitted by section 92.5.4 of this article and by Code of Ala. 1975, § 11-52-80. Special exceptions shall be granted only as provided by section 92.5.2 and section 92.5.3 of this article.

(Ord. No. 96-159, 4-25-1996; Ord. No. 07-460, § 5, 6-28-2007)

If any section, clause, provision, or portion of this article shall be held to be invalid or unconstitutional by any court of competent jurisdiction, such holding shall not affect any other section, cause, provision or portion of this article which remains.

(Ord. No. 96-159, 4-25-1996)