I Hillside Development Zone in Effect Prior to Implementation of the Environmentally Sensitive Lands Ordinance on 7/19/11 (formerly codified in Section 24.2)

I. Hillside Development Zone in Effect Prior to Implementation of the Environmentally Sensitive Lands Ordinance on 7/19/11 (formerly codified in Section 24.2)

This ordinance seeks to implement the adopted planning goals of this community with regard to public safety, conservation of resources, community design and open space and recreation.

Oro Valley is surrounded by mountains. These mountainous areas exhibit steep slopes which may contain unstable rock and soils. Development on potentially unstable soils or rock can be hazardous to life and property. Development in these areas should utilize construction methods which ensure slope stabilization and minimize soil erosion.

Further, Oro Valley’s rolling desert terrain, containing peaks, ridges and drainageways, is a valuable scenic resource which should be preserved. Significant peaks and ridges should be protected in order to preserve the Town’s unique visual setting, promote its economic well-being, and encourage tourism. Regulating the intensity of development according to the natural characteristics of hillside terrain, such as steepness of slope, significant vegetation and landforms and soil stability and existing drainage patterns, will allow for sensible development in hillside areas while minimizing the physical and visual impact of such development.

This zone provides for the reasonable use of hillside areas and related lands while protecting the public health, safety, and general welfare by:

1. Determining whether certain types of soil conditions exist (such as loose or easily eroded soils, or rocky soils), and utilizing appropriate engineering technology to result in stable slopes during and subsequent to development.

2. Reduction of water runoff and changes in the natural drainage patterns, soil erosion, and rock slides by minimizing grading and requiring revegetation.

3. Permitting intensity of development compatible with the natural characteristics of hillside terrain, such as steepness of slope, significant landforms, soil suitability, and existing drainage patterns.

4. Preservation of the scenic quality of the desert and mountain environment through the retention of significant peaks and ridges in their natural state.

5. Reduction of the physical impact of hillside development by encouraging innovative site and architectural design, minimizing grading and requiring restoration of graded areas.

6. Provision of safe and convenient vehicular access by encouraging development in the less steeply sloped terrain.

7. Promoting cost-efficient public services by encouraging development in the less steeply sloped terrain, thereby minimizing service extensions and utility costs, and maximizing access for all necessary life safety services.

The provisions of the Hillside Development Zone (HDZ) apply to development in the areas listed below:

a. Any parcel with an average cross slope of 15 percent or containing slopes of twenty-five percent (25%) or greater. Methods of analyzing slope are given in Section24.2.K.

b. Any parcel containing sloped areas of twenty-five percent (25%) or greater where the sloped area is greater than fifty (50) feet in any horizontal direction or greater than seven and one-half (7 1/2) feet vertically.

Any recorded subdivision plat approved in compliance with the Pima County Hillside Development Zone regulations may be developed in compliance with the conditions and stipulations as approved. If the plat is resubdivided after the effective date of this ordinance, September 17, 1993, it must comply with all provisions of the Oro Valley HDZ currently in effect.

a. The HDZ regulations shall apply to all property described in Section24.2.C except where the development standards prevent the reasonable utilization of property as determined by the Board of Adjustment through the approval of a variance. All HDZ applicability appeals shall be heard by the Board of Adjustment in conformance with the variance procedures established in Section 21.6.

b. The HDZ regulations do not apply to the paving of an existing driveway located on property with HDZ applicability.

c. Lots within existing, approved subdivisions on the effective date of this ordinance, and subdivision plats which have been submitted prior to the effective date of this ordinance shall not be subject to the provisions of this ordinance.

Any use permitted by the underlying zone is allowed.

All development will require subdivision plat or development plan approval, in accordance with the Oro Valley Zoning Code Revised, prior to the granting of a permit for grubbing, grading, excavation, or construction.

The following development criteria apply to all parcels that are affected by this zone. Any parcel created must meet slope/size requirements of Table 24-1. All development is subject to the Oro Valley Grading Ordinance.

a. This paragraph applies to an existing parcel where no land division has occurred, nor is land division proposed, since the adoption of this ordinance. The average cross slope (ACS) is calculated for the entire parcel. If the ACS is 15 percent or greater, Columns A and D of Table 24-1 apply.

b. This paragraph applies to any parcel of property or lot where land division is proposed or has occurred since the adoption of this ordinance. The average cross slope is calculated for the parcel prior to land division. If the ACS is 15 percent or greater, columns A and C of Table 24-1 apply. Natural open space may be designated on the parcel in accordance with Section24.2.G, to reduce the ACS percentage. Such natural open space will be excluded from the ACS calculation, but will be included in the land area for the parcel.

i) If a subdivision plat is required, all 25 percent or greater slopes (as defined in24.2.C.1.b) within the proposed lots, except for those within natural open space areas, are delineated. These sloped areas then determine the design of the development according to the following criteria.

a) Where the areas of 25 percent or greater slope are located outside the buildable area, the minimum lot size requirements of the underlying zone apply. The buildable area may be redefined by the applicant to exclude areas of steeper slope in order to comply with this requirement. Grading may occur only within the buildable area and access to the buildable area. Grading for roadway or driveway access shall not cross a 25 percent or greater sloped area unless no alternative routes exist. Driveway clearing and grading may be no wider than 30 feet.

b) Where the buildable area contains areas of 25 percent or greater slope, the minimum size required for that proposed lot is 43,560 square feet unless a greater size is required by the underlying zone. The amount of grading permitted is the amount indicated in Column D of Table 24-1, based on the area of the lot, Column B.

ii) If a subdivision plat is not required, the land area of each parcel created must comply with Columns A, B and D of Table 24-1.

a. All grading is subject to the provisions of the Oro Valley Grading Ordinance.

b. The ACS is calculated for the entire parcel. If the ACS is 15 percent or greater, columns A, B, C, and D of Table 24-1 apply.

c. Natural open space may be designated on the parcel, in accordance with Section24.2.G to reduce the ACS percentage. Such natural open space will be excluded from the ACS calculation, but will be included for density calculation. If the ACS of the remaining portion of the parcel, after natural open space designation is:

i) Less than 15 percent and contains no areas of 25 percent or greater slope, 100 percent of that portion may be graded.

ii) Less than 15 percent, but contains areas of 25 percent or greater slopes, no more than 80 percent of that remaining portion may be graded.

iii) Fifteen percent or greater, columns B, C, and D of Table 24-1 apply, based on the entire area of the parcel.

a. All grading is subject to the provisions of the Oro Valley Grading Ordinance.

b. The ACS is calculated for the entire parcel. If the ACS is 15 percent or greater, columns A, B, and D of Table 24-1 apply.

c. Natural open space may be designated on the parcel, in accordance with Section24.2.G, to reduce the ACS percentage. If the ACS of the remaining portion of the parcel is:

i) Less than 15 percent and contains no areas of 25 percent or greater slope, 100 percent of that portion may be graded.

ii) Less than 15 percent, but contains areas of 25 percent or greater slope, no more than 80 percent of that remaining portion may be graded.

iii) Fifteen percent or greater, Columns B and D of Table 24-1 apply, based on the entire area of the parcel.

When a mix of development is proposed; i.e., a combination of residential, commercial, office, or industrial land uses, each use must meet all criteria for that development, as required by this section.

Table 24-1. Slope Density Requirements
A	B	C	D
Average Cross Slope	*Minimum Area (Acres/Dwelling or Structure)**	*Density (Dwellings/Acre)**	Maximum Grading (Percentage)
Less Than 15 as Permitted by Underlying Zoning
15.0-15.9	1.00	1.00	40.0
16.0-16.9	1.00	1.00	40.0
17.0-17.9	1.25	.80	32.0
18.0-18.9	1.37	.73	29.2
19.0-19.9	1.50	.67	21.3
20.0-20.9	2.00	.50	20.0
21.0-21.9	2.25	.44	17.7
22.0-22.9	2.50	.40	16.0
23.0-23.9	3.50	.29	13.3
24.0-24.9	4.50	.22	11.9
25.0-25.9	6.00	.17	9.3
26.0-26.9	7.00	.14	9.3
27.0-27.9	8.60	.12	9.3
28.0-28.9	10.40	.09	9.3
29.0-29.9	12.80	.08	9.3
30.0-30.9	16.00	.06	8.8
31.0-31.9	23.50	.04	6.7
32.0-32.9	31.00	.03	6.7
33.0 and Greater	36.00	.027	4.0
* Or as permitted by underlying zoning, whichever density is less.

Natural open space (see Chapter 31 for definition) may be designated on any parcel, subject to the following criteria:

1. Development other than hiking trails will not be permitted within the legally described boundaries of natural open space in the Hillside Development Zone. Access roads, other than driveways, are not permitted within natural open space.

2. Natural open space will be delineated in a surveyable manner on the preliminary and final plats of a subdivision, or on the development plan, and shall be designated by legal description on a document recorded with the Pima County Recorder.

3. Natural open space may be designated as a deed restricted portion of a privately owned lot, or as a separate land parcel. This parcel may be under the ownership of a homeowners’ association, or deeded to any organization willing to accept responsibility for the perpetual preservation of the natural open space, subject to approval and acceptance by the Town of Oro Valley.

4. To protect natural open space, covenants which run with the land will be provided in favor of the Town of Oro Valley and all owners with record interest in the natural area.

5. If natural open space is designated on parcels four (4) acres or more, at least one (1) such natural open space area shall be a minimum of one-half (1/2) acres in size.

a. As permitted by the underlying zone. If the building also falls within the boundaries of other overlay zones, the more restrictive of the requirements applies. In order to eliminate large amounts of cut and fill, segments of buildings may be designed at varying elevations according to the slope of the land. For parcels with HDZ applicability per this section, building height shall be measured using a building height contour line (as defined in Chapter 31, Building Height Contour Line).

b. A variance to maximum building height may be approved by the Board of Adjustment. If a variance is granted, the Planning and Zoning Administrator shall review any residential structure up to the maximum height of the zoning and may approve said structure if such approval provides a better method of building to the land and is no more detrimental to adjacent properties than strict adherence to the development standards of the underlying district would allow. Such variance, as granted by the Board of Adjustment, shall be in compliance with the provisions of Section 21.6. Planning and Zoning Administrator and/or Town Engineer review and approval shall be required prior to the issuance of any grading or building permits.

c. The Planning and Zoning Commission shall review any commercial structure over eighteen (18) feet in the HDZ and may recommend approval of said structure to the Town Council if such approval provides a better method of building to the land and is no more detrimental to adjacent properties than strict adherence to the development standards of the underlying district.

All proposed site work (see Site definition in Chapter 31), including grading, shall comply with the Development Standards contained in the Grading Ordinance.

All exposed exterior walls and roofs of structures, retaining walls and accessory structures shall utilize the predominant natural colors found on the parcel. Satellite dishes shall be earth tone or black. White is not permitted. In HDZ zones, in residential zoning districts, colors may be approved by the Planning and Zoning Administrator. In commercial zoning districts, Planning and Zoning Commission approval of colors is required.

((O)17-05 , 06/07/17)

The Planning and Zoning Administrator may, prior to recordation of a subdivision plat or issuance of building permits, require measures, such as covenants, assurances, or homeowners’ associations, as are necessary to ensure the long-term maintenance of slope control measures.

1. The developer and/or property owner shall be responsible for the following:

a. Submitting average natural cross slope and sloped area analyses, certified by a qualified registrant, for review and verification by the Town Engineer or his/her designee.

b. Surveying, staking, and inspection of the property by a qualified registrant to determine compliance with the provisions of this Section.

c. On-site enforcement by certifying to the Town Engineer that the development complies with Section 24.2 Hillside Development Zone during the period of development.

2. If violation of any provision of the Hillside Development Zone occurs, the property owner shall be responsible for bringing the violation into compliance with the requirements of this zone. This may require restoration of the site as closely as possible to its original undisturbed condition, topography, and vegetation, in order to remove the violation.

The Average Cross Slope (ACS) of a site shall be determined by a qualified registrant in the following manner:

a. The site is depicted on a topographic map of the existing terrain, prior to any grading, grubbing, clearing, excavation, or modification, utilizing a scale no smaller than one (1) inch equals 100 feet, with the following contour intervals:

i) For sites less than five (5) acres, a contour interval of two (2) feet;

ii) For sites five (5) acres and greater, a contour interval of two (2) feet or five (5) feet.

b. The length of each contour line contained within the site boundaries on the map is measured by means of a mechanical device such as a map wheel or digitizer. This actual length is converted to scale length in feet. For example, at a scale of one (1) inch equals 40 feet (1" = 40'), a contour line with an actual map length of six and one-half (6 1/2) inches represents a line 260 feet long (6.5 x 40 = 260).

c. The sum of the lengths (L) of all contour lines is multiplied by the contour interval (I) in feet.

d. The result is multiplied by the factor .0023, which converts the square footage of the scale map to acres.

e. This result is then divided by the area (A) of the site in acres.

f. This process is mathematically represented by the formula

ACS =	(I) (L) (.0023)
	(A)

g. The answer is the percentage of the ACS for the site.

In addition to ACS requirements, any parcel containing areas with a slope of 25 percent or more shall have HDZ applicability as stated in Section24.2.C. A sloped area analysis, which must be prepared by a qualified registrant, shall identify individual slopes for design and review purposes. A detailed methodology for performing sloped area analysis is available from the Planning and Zoning Department.