1. A site analysis shall be required with any rezoning application or, if developing under existing zoning, with the submittal of a preliminary site plan/subdivision to the Planning and Development Department. The site analysis is a tool to assist in determining areas to be preserved and areas to be developed. Planning and Development Department staff shall review the applicant’s proposal and approve or make modifications for approval with regard to proposed construction areas, areas to remain undisturbed, road corridors, stormwater retention areas, and potential public/private utility areas. The base for the site analysis shall include a current aerial photo at a scale to be determined by staff. This will vary dependent upon the size of the proposed project. Specific areas within a large project may need to be provided at a suitable scale if more detail is necessary. The following information shall be included on the site analysis, as required by Planning and Development Department staff:

Rationale: Rigorous analysis of a site prior to preparing the site plan or subdivision layout will allow preservation of important site features, such as wash corridors, and significant stands of vegetation and reduce hazards from potential flooding and other natural occurrences. Analysis must use an adequate scale to allow review determination.

1. An architectural or alternative light standard to be approved by the City, shall be used. Cobra style fixtures shall not be used. (r)

Rationale: The same light standards should be used throughout the overlay district.

2. Except for government regulated signs, freeway frontage, or when approved in a comprehensive sign plan, all permanent signs shall be monument style, limited to eight feet in height. If a comprehensive sign plan is approved, the maximum height permitted to shall be the base height allowed (no additional bonus) based on street volume. (r)

Rationale: A higher level of aesthetics will be achieved through use of monument and wall signage. Comprehensive sign plans address the quality and consistency of appearance of all signage in a larger area.

3. Freeway frontage signs greater than sixteen feet in height should reflect a monument with similar materials to other signs on-site or a visual equivalent that does not use a singular pole. (p)

Rationale: Along freeway frontage, crossover structures create a need for taller signage. Elsewhere, signage adjacent to streets should be low profile to help keep views open.

4. Temporary signs greater than six square feet in size shall not be allowed, except when approved as part of a comprehensive sign plan. (r)

Rationale: Temporary signage may be in place for several years; size should be limited to reduce the visual impact because the temporary signs are not subject to the other guidelines. However, a comprehensive sign plan will address the quality and consistency of appearance of all signage in a larger area.

5. Signs should utilize materials that reflect the desert character of the area. The use of native materials, such as rock, stone, stone veneer or faux stone is encouraged. Design features, such as color or materials, should be incorporated into the sign structure to complement the architecture on-site. Masonry signs may be constructed as an extension of a wall. (p)

Rationale: A higher level of aesthetics will be achieved through use of native materials in signage and coordinating with the architecture. Use of similar materials will provide a consistent design theme in the overlay district.

6. The stucco, block, cement or masonry portions of walls and monument style signs in or adjacent to the right-of-way for Parkway "A" should be colored to blend with the desert environment. This does not include the rock, stone or stone veneer portions of these structures. (p)

Rationale: Colors will help relate the structures to the desert environment. Use of coordinating colors will provide a consistent design theme in the overlay district.

7. Box gabions and concrete channels should not be allowed unless needed for public safety. Where used, they should be designed to blend with the desert setting through color, texture, landscaping or other means. (p)

Rationale: Box gabions and concrete channels have a hard appearance that will not blend with the desert. Additionally, concrete channels can contribute to drainage problems where they interface with natural washes.

Concrete channels are not allowed.

8. Riprap should not be used unless needed for public safety. Where used, it should be used with restraint and be designed to blend with the desert setting through color, texture, landscaping and other means. (p)

Rationale: Where engineered erosion control is necessary, a more natural looking drainage way will preserve the scenic qualities of the undisturbed desert.

9. Provide view fencing adjacent to open space areas, such as wash corridors or rock outcroppings, except (a) where a roadway runs between the open space and the development; or (b) where an arterial street is located less than one hundred feet from the perimeter wall; (c) where more than one side of the back yard of a lot is adjacent to open space. In this case, one side must have view fencing and a minimum ten-foot return of view fencing should be used adjacent to the side that is all view fencing. This will typically be along the side yard. And; (d) where two rear yards are in close proximity, so that it infringes on privacy. Then one wall should provide view fencing to the open space and the other may be solid. (p)

Rationale: Opening the improved and undisturbed areas up to visual access allows passive enjoyment of these areas. It also provides visual monitoring in order to discourage undesirable and illegal activities such as dumping.

10. View fencing shall consist of a maximum six-foot high fencing, which may have a solid base of no more than two feet above finished grade of the lot, with the upper four-foot portion open to allow visibility, such as with a wrought iron fence. (r)

Rationale: Visual access to open space areas is not to be impeded by walls above two feet in height. The benefits are twofold, with unimpeded visual access homeowners can enjoy the benefits of both improved and undisturbed open space areas. Also, the open space areas become safer from undesirable activities when the eyes of homeowners are on them.

11. When adjacent to the landscape area residential subdivision and commercial perimeter walls and other walls along arterial or collector streets should vary by a minimum of four feet every four hundred lineal feet to visually reflect a meandering or staggered setback; or design features should be used to break up the appearance of a long, straight wall. Such design features may include, but should not be limited to, planters, pony walls, and dense landscaping adjacent to the wall to screen it. If design features other than meandering or staggered setbacks are used, the developer should demonstrate how the design visually breaks up long, straight wall appearance and the plan must be approved by the City. (p)

Rationale: Providing a variation in the appearance of a wall line through allowing the wall to meander or be offset or through another design feature will prevent a monotonous solid wall line along streets.

12. Stone detail of rock, stone veneer, stonework or faux stone shall be incorporated into the design of perimeter walls. (r)

Rationale: By incorporating some rock into wall design, the wall makes a connection with the physical site, echoing the geology of the site and will carry over design elements from the main roadways through the NBCC, uniting design elements.

13. Building and wall colors should be muted and blend with rather than contrast strongly with the surrounding desert environment. A color palette should be provided to the Planning and Development Department Site Planner for review and approval. Reflective materials should not be used. Accent colors may be appropriate, but should be used judiciously and with restraint. (p)

Rationale: The Sonoran Desert contains a full range of colors beyond just beige and tan, that are appropriate for building and wall colors. The colors vary from site to site and generally contain muted shades of pinks, oranges, reds, blues, violets, and many other colors. Desert wildflowers provide vibrant accent colors that could be echoed in architectural accent colors. Replicating colors indigenous to the site will assist in fitting a commercial or residential development into the site. z

1. Palm trees and other plants specified on the prohibited plant species list (see Appendix B) shall not be allowed in the North Black Canyon Corridor. The prohibited plant species list shall be provided to all purchasers of property within the NBCC and shall be listed in the Property Owner’s Association C,C&RS. These shall specifically note that trees that grow substantially taller than the native desert trees are not appropriate within the NBCC because they will impair views. (r)

Rationale: Palm trees are not indigenous and are invasive; other non-native species also create problems in the desert environment. Sonoran Desert plants would make an effective landscape statement or focal point that would reflect the Arizona Desert Southwest much more effectively. Taller trees are not typical of this desert and may impair the views that attract people to the NBCC.

2. Salvaged plant and landscape material should be used on-site to the maximum extent that can be achieved, including residential landscaping on individual lots. It must be demonstrated to the Planning and Development Department that an excess of plant material exists or relocation within the development is presumed. (p)

Rationale: Local plant and landscape material, such as boulders, removed from a site in order to develop the site, needs to be replaced on the same site to preserve the character and increase the survival rate for relocated plants.

3. In areas designated as public or private permanent undisturbed open space, whereas a small portion has been burned or previously damaged, the area will be revegetated. Revegetation shall be typical of surrounding area washes, i.e., tree-lined washes will be revegetated with trees, slopes similar to nearby slopes. The property owner’s association will be responsible for the management of private revegetated areas. Where this occurs at the edge between public and private development, the public open space will be revegetated at the same time as the private open space. (c)

Rationale: Revegetation should restore the natural appearance of the site.

4. Native Sonoran Desert vegetation should not be pruned or removed from areas identified as permanent undisturbed open space unless demonstrated to the City that a health, safety or welfare issue exists. This includes removal of dead trees or cacti. (p)

Rationale: Sonoran Desert wildlife is dependent on the habitat created by the native vegetation as it occurs in the natural environment. Dead trees, fallen saguaros and low growth on trees provide cover for a variety of native wildlife.

5. Within areas identified as permanent undisturbed open space, no grading or other disturbance shall occur except grading for trails, roadways and utility easements. Restoration of the disturbed area is mandatory and shall follow plans reviewed and approved by the City. (r)

Rationale: Disturbance should be kept to the minimum necessary to allow development in areas designated as undisturbed open space.

6. Transitional slopes to hillside areas (five percent to ten percent slope) should be graded to minimize cut and fill. (p)

Rationale: Following the contours of the land by stepping the building pads and lots, or through the use of stem walls and/or stair-stepping is visually less intrusive and minimizes disturbance. Large retaining walls are imposing and severe, whereas a series of stepped grading pads will blend and produce a softer edge where development interfaces with the desert.

7. The edge of private, common turfed open space areas shall be no closer than twenty-five feet from undisturbed open space, and no closer than fifty feet from desert wash banks. In all turf areas, the use of common Bermuda grass shall be prohibited in favor of hybrid Bermuda varieties. (r)

Rationale: Care must be taken to prevent the unwanted spread of turf into desert areas, especially the wash system. Common Bermuda spreads more easily than sterile hybrid varieties.

1. All washes identified on Map B shall be preserved in an undisturbed condition. (r)

Rationale: Washes that are part of the Sonoran Preserve or provide connectivity for wildlife corridors are identified. Portions of these washes were designated for preservation through approved zoning cases, plus the upstream and downstream portions of the washes are identified on this map.

2. The area of a wash to be maintained undisturbed, for washes identified on Map B that have a one hundred-year peak flow over five hundred cfs shall be based on the following formula: the setback as measured from the floodway on each side of the wash shall average 1.0(Q100)0.5, with a minimum setback of seventy-five percent of 1.0(Q100)0.5.

Note: This standard shall be reviewed within one year of the initial ordinance adoption to address open space the impacts of wildlife corridors.

It is the intent of these criteria to enhance requirements by other flood control agencies, not to replace. (r)

Rationale: Washes do not function on individual parcels, but contribute to a larger fluvial and wildlife system, which requires interconnection in order to provide consistency of vegetation and diversity of wildlife. Altering natural drainage patterns can have significant impacts upstream and downstream.

3. The area of a wash identified on Map B to remain undisturbed, for washes that have a flow of less than five hundred cfs, should allow sufficient setback to allow for wildlife passage outside of the incised wash. (p)

Rationale: Smaller washes in certain locations may also need to function as wildlife corridors, providing connectivity between different areas of the Sonoran Preserve.

4. No major structural changes or improvements shall be allowed in the washes identified on Map B to remain undisturbed, and vegetation shall be left in place except as follows:

Rationale: If a wash is identified for preservation, disturbance should be kept to the minimum necessary.

5. Roadways shall be bridged or trail underpasses provided over wash and trail corridors as identified on Map B, subject to engineering. Bridges shall, at a minimum, reach from bank to bank. Other bridge crossings may be identified through the rezoning process. A grade separated crossing to accommodate equestrian trail users (or as approved by the City) shall be required at the identified bridged crossing. (r)

Rationale: Trails should not cross over streets that carry high volumes of traffic as it endangers trail users. Skunk Creek and Sonoran Wash are major washes that have also been identified as significant drainage and wildlife corridors. Substantial clearance is required to accommodate equestrian users.

6. Where a public or private multi-use trail easement is located in a wash corridor, it shall should be placed above the bank or the wash and not within the floodway, except where it crosses the wash. If the trail passes under a bridge, it must be located at least three feet above the sandy bottom of the wash or as approved by the City. (p)

Rationale: Wash corridors with public trails or private trails with public access easements should shall provide a safe crossing under bridges in minor flood events, such as a two-year flood event, the trail should be placed above the wash bottom.

7. Access improvements to sites using private streets with bridges, culverts or dip sections to cross washes, shall include means for sediment and debris removal, and meet City trail guidelines. A management plan for debris and sediment removal for the homeowner’s or property owner’s association shall be included in a development’s covenants, conditions and restrictions (CC&Rs) and approved by the City. The CC&Rs shall include a statement defining the responsibility of the property owner’s association for this maintenance. (r)

Rationale: Stormwaters carry sediment and debris that can build up behind dry wash crossings or block the path of wet wash crossings. Property owners’ in an association need to maintain private wash crossings. Purchasers of property that include privately held facilities should be notified of the future maintenance responsibility and expense.

8. Dry wash crossings should be designed to run bank to bank to allow passage of wildlife in the wash with a minimum of five feet horizontal by five feet vertical clearance under a culvert or bridge where the wash is a minimum of five feet deep and five feet wide. (p)

Rationale: Wildlife will not move under closely confined culverts or bridge crossings. However, there may also be opportunity or a need for dry crossings over smaller washes.

9. When a bridge crosses a public trail, bridge widths of fifty feet on collector, major arterial and arterial streets shall be lit underneath for the safety of trail users, as approved by the City. (r)

Rationale: Lighting will enhance safety in this case.

10. The construction area for a roadway or utility crossings shall be clearly marked with fencing to minimize impact on existing vegetation during construction. The entity responsible for the improvement shall provide documentation of how wash banks will be stabilized and restored to a natural appearance where it must be disturbed for infrastructure, as approved by the City. (r)

Rationale: Defining and containing the allowed grading area prevents overlap into areas designated for preservation. Where disturbance must occur, the impact should be minimized.

11. Where culverts are constructed, minimize the concrete while providing the opening required by hydrolics and to blend with the adjacent desert via materials and landscaping after construction. (p)

Rationale: Culverts can be visually obtrusive. Design can minimize visual the impact by minimizing the concrete structure and blending materials and colors.

12. Constructed access points to public open space, the Sonoran Preserve, public parks and related facilities shall be identified by, coordinated with, and approved by the City. Construction of unauthorized access points shall not be allowed. (r)

Rationale: The Parks, Recreation and Library Department has specific needs and criteria for access points to open space areas that they manage, and staff has identified general locations for park related facilities for City residents.

13. When public trails and connecting private trails and wildlife corridors are provided they shall be identified on plans submitted to the City. Both on-site and off-site connections shall be shown on the same plans. (r)

Rationale: The Parks, Recreation and Library Department has planned for a network of public trails to interconnect to insure continuity of the trail system and avoid conflicts.

14. Maintain significant views of the Sonoran Preserve Mountains, Skunk Creek and the Sonoran Wash from trail and roadway corridors and other points of higher elevation, as identified on Map C. (p)

Rationale: Views of open space areas must be provided and preserved. The visual effect of open space is an important amenity a principal factor leading individuals to locating their businesses and/or homes in Sonoran Desert areas.

15. Retention basins in all development should be designed to blend with the natural desert area for example, with curvilinear edges. (p)

Rationale: The intention is not to increase the size of retention basins, but to soften edges and blend the landscaping with the natural desert. This does not preclude the use of turf in basins that also serve as common recreation areas, nor does it require a slope of less than four to one (4 to 1) ratio. Rather, surface variation instead of straight edges and flat surface, natural materials and native vegetation should be incorporated into the design.

1. North Valley Parkway (Parkway A), Lone Mountain and Dove Valley Roads will be bridged as they Cross Skunk Creek through the Sonoran Preserve. Allowing unimpeded views of the creek both north and south will showcase an important feature in the NBCC. Development at both ends of the bridge should shall allow the views to open up by providing the deeper portion of the required average set back at the preserve edge along the North Valley Parkway (Parkway A), and arterial roadways. (p)

Rationale: The view opening on to Skunk Creek Wash will allow a smooth transition between the built environment and the natural environment in the Sonoran Preserve.

2. Landscaping within and adjacent to the right-of-way along North Valley Parkway (Parkway A), Lone Mountain and Dove Valley Roads shall include, at a minimum, at least two of the combination of Palo Verde, Palo Brea, Ironwood and Mesquite species of trees. While the combination of trees may vary among developments, the combination of these species shall provide a consistent image along the roadways. Trees shall vary in maturity, but at least seventy-five percent but shall be a minimum of two-inch caliper in size or a multi-trunked equivalent. If a shortage of these four species of trees is documented, the City may approve the use of other trees from the approved plant species list (Appendix A). (r)

Rationale: The specified combination of trees will provide a shaded movement corridor with a low profile growth pattern to preserve the Sonoran Desert image. Overall consistency of image is maintained by specifying trees while some variation is allowed.

3. Landscaping within the right-of-way along North Valley Parkway (Parkway A), Lone Mountain Road and Dove Valley Road shall include trees spaced to reach canopy to canopy at maturity placed so as to provide a minimum of fifty percent shaded coverage of the sidewalks. (r)

Rationale: Shaded corridors provide relief from the sun, which is important for pedestrians. Requiring the maturity and size will encourage use of salvaged material.

4. Landscaping should be blended among adjacent developments to provide a continuous appearance and to avoid a distinct or abrupt change. (p)

Rationale: North Valley Parkway (Parkway A), is the primary north/south corridor and should serve to establish a sense of identity and continuity. Lone Mountain and Dove Valley Roads will serve as the primary east/west corridors.

5. The landscape setback along North Valley Parkway (Parkway A), as required by the appropriate zoning category (except within the core), should at a minimum meet the average required depth, but should vary in depth by minimum of four feet to create a meandering or staggered setback. Walls within or adjacent to the landscape area should vary by minimum of four feet every four hundred lineal feet to visually reflect the meandering or staggered area, or design features should be used to break up the appearance of a long straight wall. Such design features may include, but should not be limited to, planters, pony walls, and dense landscaping adjacent to the wall to screen it. If design features other than meandering or staggered setbacks are used, the developer should demonstrate how the design visually breaks up the long straight wall appearance and the plan must be approve by the City. (p)

Rationale: Long straight lines seldom occur in the environment. A meandering or staggered setback will have a more natural appearance. Other means may be used to alter the appearance of straight lines.

6. The landscape setback along North Valley Parkway (Parkway A), Lone Mountain Road and Dove Valley Road, within the core area shall be an average of twenty feet (or as required by the zoning if a greater setback required) shall not be less than fifteen feet from the right-of-way at any given point, regardless of zoning category. (r)

Rationale: North Valley Parkway (Parkway A), runs the length of the NBCC and will be a major transportation corridor within the area. A consistent image along the parkway will provide a sense of identity and integrate development with the desert setting in the NBCC. The minimum setback will maintain the desert parkway image in relation to the higher intensity of development in the core area.

7. No more than fifty percent of the required landscape setback adjacent to North Valley Parkway (Parkway A), can be used for retention. Provision should be made to allow for a trail above the retention, where planned. (p)

Rationale: Landscape setbacks are intended to provide a transition to development and visual relief from hardscape. While it may provide limited retention, that is not the reason for or function of these setbacks. When used for a large amount of retention the setback takes the appearance of a ditch (barrier) to a site.

8. Entryways to a site or subdivision should include increased setbacks and the deeper portion of the required setback along North Valley Parkway (Parkway A). Parkway "A" should be located at the entry into a site, with enhanced landscaping to create a focal point. Enhanced landscaping means it should be greater in the number and/or size of plants, and may include a particularly large or unique specimen. The use of additional trees that include the four street trees (Palo Verde, Ironwood, Palo Brea and Mesquite), is strongly encouraged. (p)

Rationale: Concentrated landscaping draws the eye in a desert environment. Located in the deeper portions of the setback, it will create focal points along North Valley Parkway (Parkway A).

9. Parking lots located adjacent to North Valley Parkway (Parkway A), shall be screened along the roadway by a wall incorporating stone, stone veneer, faux stone or rock, or by an earth berm rising a minimum of three feet above the grade of the parking lot. (r)

Rationale: Expanses of parking lots are visibly unattractive and increase the perception of heat islands in the desert setting.

10. A public multi-use trail is identified and is to be provided along the east side of North Valley Parkway (Parkway A) and along Lone Mountain and Dove Valley Roads, in addition to the required sidewalk, with the exact alignment to be approved by the City. (r)

Rationale: The City’s General Plan calls for a network of multi-use trails throughout the City. Additional trails may be added in the future through an amendment process to provide further connections.

11. Consider the location and relationship of public and private trails and transit stops in site design. (c)

Rationale: Providing transit access at trail intersections with streets will enhance access to the trail network and encourage the use of alternative transportation.

12. Enhanced landscaping, especially the provision of extra trees for shade, is encourage at transit stops. (p)

Rationale: Extra shade will provide relief from the sun for those waiting for transportation.

13. The stucco, block, cement or masonry portions of walls in or adjacent to the right-of way for North Valley Parkway (Parkway A), should be colored to blend with the desert environment. (p)

Rationale: The walls and masonry will blend with the desert environment if appropriately colored.

1. On residential subdivisions contiguous to parks and open space areas managed by the Parks, Recreation and Library Department (PRLD), such as the Sonoran Preserve, neighborhood access to those areas for residents in the immediate neighborhood should be provided in cooperation and coordination with the PRLD. (p)

Rationale: Residents in neighborhoods contiguous to open space areas managed by the PRLD would benefit from and have greater appreciation of those open spaces when they have some access to them.

2. Within an individual development, view corridors for residents may be preserved though the spacing of development of large lot single-family residential, attached single-family development, or multi-family development, or by the placement of single loaded roadways, culs-de-sac and open space areas such as trails and retention basins. The careful placement of single and two-story housing can also increase the opportunity for views. The site analysis should assist in locating view corridors within developments. (c)

Rationale: Views of the desert preserve will reinforce the community’s relationship to the desert environment and serve as amenities for local developments.

1. In multi-family development no parking shall be located contiguous to public or private preserve open space. Except, parking may be allowed if it is shared parking, subject to a joint use agreement developed with the Parks, Recreation and Library Department. Development shall be designed so that some residential units shall face on to the preserve open space. (r)

Rationale: Development contiguous to public or private preserve areas will be able to take advantage of the view afforded by open space, as well as provide informal monitoring of activity in the area.

2. In multi-family development adjacent to public or private preserve open space, a minimum of fifty percent of the required improved open space shall be located contiguous to the preserve edge. The edge of the improved open space contiguous to the preserve edge shall be equal to or greater than the depth. (r)

Rationale: Providing the improved open space for development adjacent to preserve open space will allow access for all residents within the development and encourage activity adjacent to or within the preserve areas.

3. Where a multi-family development is located adjacent to public or private preserve edge, a physical access point should be provided. (p)

Rationale: Should be able to easily access the preserve area for recreation and enjoyment. This does not preclude a secured access point, such as a keyed and gated entry.

1. Single-family residential development adjacent to public or private preserve open space shall include the following design elements (r):

(c) Along the public or private preserve open space edge one or more of the following design treatments shall be used. A minimum of sixty percent of the edge treatment shall consist of 1), 2), 3), or 4) below. The remainder of the edge may consist of any of the following design treatments provided that under 1) and 5) below, the length of the edge shall not exceed one thousand feet without utilizing one of the alternative treatments;

(1) A cul-de-sac design which provides an improved trail on private open space connecting to the Sonoran Preserve. An open space connection between the cul-de-sac and adjoining public or private open space edge shall be provided. The minimum width of the open space connection shall be defined by a line running along the public or private preserve open space edge connecting the rays of a one hundred forty degree angle measured from the center of the cul-de-sac.

(2) A public or private street along the public or private preserve open space edge;

(3) Private improved or undisturbed open space (less than five hundred [feet] in width) where the minimum depth is one hundred feet or where the open space is located between the public or private preserved open space and an adjacent street;

(4) An equivalent creative alternative as approved by the City that reflects diversity, together with visual and physical access.

(5) Lots that back up to the public or private preserve open space edge with setbacks provided when necessary to accommodate drainage and maintenance access as approved by the City.

2. A single loaded street or cul-de-sac opening adjacent to public or private preserve open space should be designed to (p):

Rationale: The intent of the roadways is to open up views of the open space. It defeats the purpose if construction damages the natural features or creates excessive scarring.

3. Lots with two or more sides abutting undisturbed open space shall be designed with obtuse angles (> ninety degrees) rather than ninety degree or acute angles (< ninety degrees) to avoid sharp corners or sudden narrowing of connecting open space. (r)

Rationale: The angles will produce a gradual narrowing from the adjacent open space leading into the corridors. This will better blend development with the environment and minimize sudden constrictions.

4. A minimum of thirty percent of the cumulative frontage of wash corridors identified on Map B or as otherwise preserved in an undisturbed or naturalized state shall be designed to ensure that the edge treatment remains open and unfenced. An open edge treatment shall be considered as follows: (r)

Rationale: Single loaded streets and culs-de-sac are effective at providing both visual and physical access to open space, including access for emergency vehicles or maintenance. With no other structure to block views, they also allow for visual monitoring of activities and thus, discourage unwanted activities such as dumping.

5. Residential subdivision layout shall should be sensitive to the topography and geologic features of the site and be designed accordingly. If significant stands of vegetation or topographic features, such as washes or rock outcroppings, are present on the site they should be preserved in the site design. (p)

Rationale: Too often subdivision design has adopted the practice of designing the lot layout first, then looking at the site to determine the amount of grading necessary. To achieve a higher aesthetic level of design, the site opportunities and constraints need to be evaluated first before street and lot layout. Design of the site then will take into consideration the opportunities and constraints, incorporating natural features and significant landscaping at every opportunity.

6. Street patterns and lot design shall allow direct access to washes or open space areas for maintenance of annual and non-native vegetation to prevent fire hazards and allow Fire Department access in case of fire. Design methods may include a combination of single loaded streets and/or open spaces between lots. Access might logically be provided at the edge between development and preserved open space. Points of access should be a maximum of six hundred feet apart with openings a minimum of forty feet wide to allow for fire breaks and access. Openings are to incorporate existing vegetation or be landscaped and shall maintain an access way twelve feet wide for Fire Department equipment. To clarify, this does not imply that blading of a wash is allowed. Rather, native vegetation is to be preserved in place, but non-native vegetation may be carefully removed. (r)

Rationale: In the past, development has backed closely to wash corridors and not provided adequate access for management or fire control of exotic plant material overgrowth. Providing breaks when backing to a wash will allow adequate access for both management and fire control.

7. Along undisturbed open space, where a building envelope is not used, no more than fifty percent of the homes shall have a building height greater than one-story or twenty-four feet measured to top of the parapet or the top of the ridge on sloping roofs. Where building envelopes are used, there is no restriction on the number of homes greater than one story, except as noted below. Regardless of lot grading, no more than two homes above one story or twenty-four feet may be adjacent to one another. A chimney may be constructed to a maximum of three feet above the highest point of the structure. (r)

Rationale: For view preservation and to blend into the desert environment, buildings must maintain a low single-story profile to be in character with adjacent Sonoran Desert vegetation which generally reaches a mature height of approximately twenty-two to twenty-five feet. By maintaining a lower building height the sense of open space will be enhanced.

8. All lot grading adjacent to areas to be preserved must be protected by a chain link fence or equivalent approved by the City with one access point provided that is located where the drive or driveway will be located. All parties involved in construction shall be made aware of the fence and the reason for it. Construction fence is to remain intact until completion of construction. (r)

Rationale: In order to preserve fragile undisturbed desert vegetation and habitat it is necessary to restrict activity outside of the building envelope.

1. All improvements, including driveways, except utilities, shall be located within a building envelope, occupying no more than fifty percent of the lot up to a maximum of twenty thousand square feet area of the lot area, whichever is less. (r)

Rationale: By establishing a building envelope, a portion of each lot is preserved and the character of the area is established, which creates value for all the residents.

2. The building envelope may require greater setbacks than the minimum guidelines stated below due to significant vegetation or topographical features on the site to be maintained in an undisturbed condition, such as rock outcroppings, significant stands of vegetation, and/or specimen trees or saguaros. Location of the building envelope on the site should be determined through review of the required site analysis and landscape inventory by the Planning and Development Department Landscape Architect. The minimum setbacks defined in this ordinance are not grounds for any increases in the size of the building envelope. The potential building envelope or gradeable area must be identified on all plan submittals for the Planning and Development Department Plan Reviewers. Lots to be developed with building envelopes are to be designated as desert lots (DL) on the site plan and final subdivision plat. Area outside of the building envelope is to remain permanent undisturbed open space and to be designated as such on all plans submitted to the City of Phoenix. (p)

Rationale: The native Sonoran Desert is the major component forming the identity of much of the North Black Canyon Corridor (NBCC) and therefore is to be maintained in an undisturbed condition when advantageous to do so. Much of the NBCC area is comprised of pristine Sonoran Desert which, considered an amenity, will add much to the aesthetics of estate lot development in the area.

3. The site analysis, as approved by the City staff, should be used to determine appropriate setbacks from any property line for the building envelope that should remain undisturbed natural desert, except for allowance of a driveway from the front setback, or a single shared driveway from the side setback. The site analysis identifies significant features to be preserved by setbacks to protect such features. Alternatively, varying side setbacks between lots can result in greater undisturbed tracts and open views between units. (p)

Rationale: To protect significant Sonoran Desert features as identified in the site analysis, single-family residential development using the building envelope need to provide a substantial native landscape setback so that the residential development blends into the surrounding desert.

4. Private driveways to individual lots may be composed of stabilized decomposed granite indigenous to the area or matching in color. Materials used are to meet approved dustproofing guidelines. If used, an edging, of a compatible color, is to be provided to keep the decomposed granite contained in the driveway. (c)

Rationale: A stabilized granite drive would blend into the context of the Sonoran Desert.

5. Local streets shall be designed to meet rural street guidelines as developed by the Street Transportation Department and approved by City Council. (r)

Rationale: Upon development of rural street guidelines, they would be applied to any new rural type single-family development. Cross reference subdivision ordinance.

6. Rural lighting guidelines shall apply as defined by the streetlighting policy adopted by the City Council. (r)

Rationale: One of the aesthetics sought by people or living the Sonoran Desert is the darker night sky.

7. Individual lot grading plans shall be submitted for review and approval by the Planning and Development Department for lots eighteen thousand square feet and larger. Vegetation and topographical features, such as specimen plants, washes and rock outcroppings, are to be identified on the plans. (r)

Rationale: Individual grading plans showing topographical features will assist the builder and Planning and Development Department Plan Reviewers in identifying key natural features on a site.

8. On single-family lots developed with a building envelope, perimeter walls or fences around the development site or individual property lines should not be allowed. Walls or fences may be located around the edge of the building envelope but shall should not be required. The appropriate location for walls or fences should be determined by the required site analysis. Walls and fences should be designed to blend into the desert environment by addressing the color and alignment of the structure. They should not be constructed in a straight line greater than twenty-five feet unless architectural relief, varied setback or a decorative element is introduced to break up the appearance of the straight line. They may be prohibited, or view fencing may be required in some places, depending on topography and proximity to public open space. (p)

Rationale: Constructing fences or walls on individual lot lines for properties developed with building envelopes defeats one of the goals of opening up the space between homes. Keeping fences only around the building envelope (within the envelope) allows wildlife to move about more freely, preserve views and promotes social interaction. Straight lines rarely occur in nature, so addressing the alignment as well as the color of walls and fences will help blend development into the desert setting.

9. Shared access drives for two or more lots or parcels should be encouraged whenever possible. A maintenance agreement among property owners or stated in homeowner associations or CC&Rs is strongly recommended where shared driveways are constructed. (c)

Rationale: This will allow more area to remain as permanent undisturbed open space.

10. The private area located within the building envelope, which would typically be the rear yard or a courtyard, shall not contain plants from the prohibited plant species list (Appendix B). The prohibited plant species list shall be provided to the home owners associations (HOAs) and purchasers of property within the NBCC, and shall be listed in the CC&Rs of the HOAs. Palm trees shall not be allowed. An exception to this is the use of turf in the rear yard. (r)

Rationale: Large lot single-family development using building envelope design needs to be compatible with the surrounding Sonoran Desert and not introduce exotic and invasive plant material.

1. The NBCC will be the subject of a future more detailed core plan, which will detail more specific design criteria including building height, orientation and reflectivity, among other design issues.