TABLE OF CONTENTS LIST OF FIGURES

Transcription

1 TABLE OF CONTENTS INTRODUCTION... 1 HYDRAULIC EVALUATION... 7 TRAFFIC EVALUATION & RECOMMENDATION... 8 UTILITIES GEOTECHNICAL EVALUATION ENVIRONMENTAL OVERVIEW AESTHETICS, WILDLIFE, AND RECREATION STRUCTURES OVERVIEW PUBLIC MEETING LIST OF FIGURES FIGURE 1: ALIGNMENT ALTERNATIVES... 3 FIGURE 2: PREFERRED NORTH ALIGNMENT ALTERNATIVE... 4 FIGURE 3: SONORAN PRESERVE... 5 FIGURE 4: LAND OWNERSHIP... 6 FIGURE 5: PROPOSED ROADWAY AND INTERSECTION CONCEPTS... 9 FIGURE 6: FLY OVER CONCEPT FIGURE 7: ROADWAY CROSS SECTIONS FIGURE 8: URBAN AND SCENIC CROSS SECTIONS FIGURE 9: FLY OVER DECORATIVE TREATMENTS FIGURE 10: PRIMARY AND SECONDARY CROSSINGS FIGURE 11: TERTIARY CROSSINGS FIGURE 12: CONCEPTUAL TRAIL SYSTEM...22

2 INTRODUCTION The purpose of the study is to determine a traffic efficient, environmentally sensitive alignment and define right of way needed to construct Sonoran Parkway and portions of Dove Valley Road, Tatum Boulevard, and Black Mountain Parkway. A stakeholder meeting was conducted during the initial phase of the Sonoran Parkway Corridor Study in July Attendees included representatives from the Maricopa County Flood Control District, State Land Department, Desert View and North Gateway Village Planning Committees, City of Phoenix Street Transportation Department, civil, geotechnical, structural, environmental, wildlife and recreation subconsultants. After developing goals and reviewing the information gathered during Phase 1 of the study, the attendees were split into teams and asked to propose their own alignments, which were later shortlisted into five alignment alternatives. North Alignment The alignment crosses Cave Creek Wash at the northern most point of any of the alternatives. It is north of the existing mining operation and is the favored crossing point of the Maricopa County Flood Control District. South Alignment The alignment travels south of the existing mining operation through the Cave Buttes Recreational Area. Cliff Alignment The alignment crosses Cave Creek Wash at a vertical 30-foot high cliff on the east bank. This alignment is at the northern edge of the mining operation. Center Alignment The alignment travels through the center of the existing mining operation. Split Alignment The alignment has two one-way roadways one mile apart traveling north and south of the mining area. Following the identification of the five alternatives, the alignments were presented at the following stakeholder meetings. Desert View Village Planning Committee, September 10, 2002, Paradise Community Center Public Meeting Dry Run, September 12, 2002, City Hall North Gateway Village Planning Committee, September 12, 2002, Deer Valley Community Center TEOC Meeting, September 19, 2002, City Hall Public Meeting, September 19, 2002, Pinnacle Peak High School Sonoran Preserve Committee, September 23, 2002, City Hall Surface Transportation Advisory Committee, October 3, 2002, City Hall Steering Committee, October 29, 2002, City Hall The north alignment was the clear preferred alternative chosen by the stakeholders. The north alignment was modified to provide direct connections to Tatum Boulevard, Black Mountain Parkway, and Dynamite Boulevard. The interpretive center will be located closer

3 to the western bank of Apache Wash. Figure 2 illustrates the modified north alignment. Figure 3 displays the proposed limits of the future Sonoran Preserve, and Figures 4 shows the land ownership in the area. The modified north alignment was presented at the following committee and stakeholder meetings: Steering Committee Meeting, March 25 th, 2003, Phoenix City Hall Sonoran Preserve Committee, May 19 th, 2003, Phoenix City Hall Surface Transportation Advisory Committee, June 5 th, 2003, Phoenix City Hall Desert View Village Planning Committee, June 13 th, 2003, Paradise Valley Community Center Public Meeting, June 10 th, 2003, Paradise Valley Community Center North Gateway Village Planning Committee, June 12 th, 2003 Phoenix Parks and Recreation Board, June 19 th, 2003 Input from the committees and stakeholders were used in determining the final alignment for Sonoran Parkway.

4

5

6

7

8 HYDRAULIC EVALUATION A preliminary evaluation to approximate the size and number of drainage crossings along the proposed roadway alignments was performed utilizing information from previous studies, Federal Emergency Management Agency (FEMA) Flood Insurance Studies (FIS), aerial mapping and USGS 7.5-minute quadrangle maps. Drainage crossings were located along each roadway alignment and structures were sized based upon several different criteria. Drainage Structures Drainage structure types and sizes were initially established to accommodate the 100-year peak discharge estimated at each drainage crossing. However, other criteria were also considered in the ultimate selection and sizing of each structure, including: Potential use for pedestrian, equestrian, or wildlife trails; The extent of floodplains, floodways and/or lateral erosion hazard zones; The amount of cover or fill at a drainage crossing; Existing drainage structures along the same watercourse. floodplain/floodways, erosion hazard zones or by the proposed vertical alignment of the roadway. Drainage Crossing Peak Discharge Estimates Peak discharges were established by either adopting values from previous drainage studies or by using techniques developed in the Desert View Arterial Street Drainage Structure Analysis (Desert View ASDSA, JE Fuller, August 2001). Drainage areas were delineated using aerial mapping, and USGS 7.5-minute quadrangle maps. The delineated areas are preliminary and do not account for numerous and complicated flow splits evident in the natural watershed areas. At a few drainage crossings, the drainage areas extended beyond the available data or information was not available from previous studies. In these instances, the culvert types and sizes were based upon existing culverts along the same watercourse or by engineering judgment. For small flows suitable for pipe culverts, a 36 pipe was the only size considered. For larger flows, only reinforced concrete box culverts with a minimum height of 4 ft. were proposed. At watercourses such as Apache Wash or Cave Creek Wash, bridges are proposed with the bridge lengths estimated based upon

9 TRAFFIC EVALUATION & RECOMMENDATION An evaluation was performed to determine roadway and intersection configurations needed to adequately serve predicted City of Phoenix general plan build out traffic volumes. The capacity of arterial roadway facilities is based on the ability of arterial intersections to accommodate peak hour volumes. Therefore, the capacity of Sonoran Parkway will be directly related to the intersection capacities of Sonoran Parkway with Dove Valley Road, and Tatum Boulevard. Build-out daily and peak hour turning movement volumes are presented in Figure 5. Based on the provided information, assumptions and findings presented in the full report, the following conclusions were reached: Sonoran Parkway West of Dove Valley Road will be a City of Phoenix cross section A (six lane divided shown in Figure 8). Dove Valley Road will be a City of Phoenix cross section Z (four lane divided shown in Figure 7) given the following: Design speed of 60 mph with a posted speed of 50 mph. Very limited access in terms of driveways, cross streets and frequency of signalized intersections (1/2 mile spacing recommended). Sonoran Parkway and Dove Valley Road Intersection will connect Sonoran Parkway and Dove Valley Road from the west to the Sonoran Parkway scenic corridor to the east. An interchange is necessary since an at-grade intersection will not satisfy the traffic demand in the area. A simple fly-over is considered the best option. A concept of the proposed flyover is illustrated on Figures 5 & 6. Sonoran Parkway Scenic Corridor will use a City of Phoenix cross section Z (six lane divided shown in Figure 8) given the following: Design speed at 65 mph with a posted speed of 55 mph No access allowed between Dove Valley Road and Tatum Boulevard Sonoran Parkway and Tatum Boulevard intersection will connect the Sonoran Parkway scenic corridor to Tatum Boulevard and Black Mountain Parkway. An interchange is necessary since an at-grade intersection will not satisfy the traffic demand in the area. A simple fly-over is considered the best option. A concept of the proposed flyover is illustrated on Figure 5 & 6. Tatum Boulevard will be a City of Phoenix cross section CM (four lane divided shown in Figure 7) provided that the roadway has very limited access (1/2 mile spacing recommended) with a design speed of 60 mph and posted speed of 50 mph.

10

11

12

13

14 UTILITIES All utilities will be present in the area because of urban areas on either side of the project. However, some utilities may use the Sonoran Parkway Corridor as a connection point between the Black Canyon Highway corridor, and the Northeast Phoenix area. Specifically: APS plans to have a 69kV line on either Carefree Highway, or Sonoran Parkway, but not both. It will likely be underground next to Sonoran Parkway in 2 5 conduits. APS forecasts the need for this line in 2010 or 2011 depending on demand. City of Phoenix water will have a 78 transmission line on the west reducing to a 66 line on the east, plus a distribution main. The preferred location is under the pavement. The City of Phoenix will also have sewer lines running in the area, and it is unlikely they will be continuous through the preserve. Currently, Southwest Gas plans on using the North Valley Parkway Corridor to service the Sonoran Foothills (west end of Sonoran Parkway) area. They do not yet know if it will be necessary to have facilities running through the preserve. Cox is still waiting to see how the area develops. They have service on both sides of the preserve, and will wait and see if connectivity is needed. If they do ever install facilities, it will likely be fiber optics requiring 2-4 way 2 conduits that can be placed in with APS s facilities. AT&T has no current plans but will reassess in the future. Qwest has not finalized any plans as yet but future facilities would be underground if required. The utility companies stressed that the need for their services are market driven, and specific plans for facilities won t be known until more is known about how the area will develop. However, those utilities that do choose to locate within the sonoran parkway corridor will place their facilities underground.

15 GEOTECHNICAL EVALUATION The purpose of the geotechnical study was to research the geologic conditions in the proposed Sonoran Parkway study corridor through review of available literature and field reconnaissance, and to provide a preliminary assessment of the geotechnical issues associated with these conditions. The tasks performed included field exploration, mapping, limited soil sampling for classification purposes, review of selected geologic maps and aerial photographs, soil surveys, and preparation of this report. Some of the younger deposits exposed in the natural drainages are prone to erosion. Some of these same materials may experience occasional perching of groundwater after significant rainfall events. Preliminary plans call for net filling over the roadway profile; therefore, identification of suitable borrow sources will be an important consideration for the project. The geotechnical study indicated the presence of five relatively distinct geologic groupings, each with different engineering characteristics: Relatively young Holocene age deposits associated with active and abandoned stream channels and flood-prone areas. Late Pleistocene age alluvial fan and terrace deposits. Middle Pleistocene age alluvial fan and terrace deposits. Early Pleistocene age alluvial fan and conglomerate deposits. Bedrock of varying age and composition. To varying degrees, the alluvial deposits exhibit potential for volume change upon wetting (i.e., shrink/swell or hydrocollapse). Many of these deposits are expected to be very coarse and/or caliche-cemented, which will affect their suitability for re-use as fill materials and their excavation characteristics.

16 ENVIRONMENTAL OVERVIEW The study area lies in the Basin and Range Physiographic Province of Arizona. More specifically, it is situated in a relatively level area between the Union Hills to the south and a smaller chain of hills to the north within the Sonoran Desertscrub Biotic Community. Portions of the study area have been previously disturbed by off-road vehicle travel and cattle grazing; however, the majority of the study area is relatively undisturbed open desert. The lack of development within the study area provides for unrestricted wildlife movement, as well as connectivity among diverse habitat types used for foraging, cover, and reproduction. Trees are not confined to washes and occur between washes and on hillsides, and the area is rich in vegetation and wildlife native to the local desert. Suitable habitat for the federally listed endangered cactus ferruginous pygmyowl and suitable foraging habitat for the federally listed endangered lesser longnosed bat is present throughout the study area. In addition, three Arizona Game and Fish Department Wildlife Species of Concern in Arizona, the Arizona toad, Sonoran desert tortoise, and Townsend s big-eared bat, could also potentially occur. Two 100-year floodplains are present and are associated with Cave Creek and Apache Wash, and U.S. Army Corps of Engineers jurisdictional "waters of the U.S.", including Cave Creek, Apache Wash, Sonoran Wash, and numerous small washes, dissect the study area. Sensitive noise receivers include the developing residential area at the western end of the study area and potential future development on other private lands. The Cave Buttes Recreation Area is present in the southcentral part of the study area. No known hazardous materials concerns exist in the study area beyond underground storage tanks and a hazardous waste handler located in the developed area along Cave Creek Road at the eastern edge of the study area. There is a large mining operation in Cave Creek and other smaller mining disturbances in the study area. An estimated 30 percent of the study area has been previously surveyed for cultural resources. Seventeen archaeological surveys have been conducted within the study area, and 40 sites have been identified (36 prehistoric, four historic). The previously conducted archaeological surveys were performed for a variety of projects including waterline easements, commercial and residential development, flood control, geotechnical testing, and underground utilities. Areas surveyed (and cultural sites recorded) are concentrated around Cave Creek and Apache Wash, with one large surveyed area located in the residential development in the western part of the study area. A part of the National Register of Historic Places-listed Cave

17 Creek Dam Archaeological District is located in the south-central part of the study area. The preferred (north) alignment appears to have the lowest number of environmental impacts of the five alternatives. The north alignment avoids concerns raised from the other alternatives, including: Avoids cliff habitat on Cave Creek Avoids Cave Buttes Recreational Area Avoids large open pit mining operation on Cave Creek Does not cross National Register of Historic Places The only concern that is raised by the north alignment, over the cliff, and center alignments is the curvilinear nature will require more ground disturbance.

18 AESTHETICS, WILDLIFE, AND RECREATION The incorporation of the future Sonoran Parkway into the study area has included the analysis and evaluation of numerous aesthetic design elements. They have been evaluated in their ability to maintain the integrity of the existing desert environment by minimizing the area of disturbance. These elements include: Roadway Alignment Transportation Routing Vistas and View Analysis Slopes Retaining wall and natural material alternatives Re-vegetation Structure Aesthetic Treatments Incorporation of Wildlife and Human trails Sonoran Preserve Edge Treatment Street Lighting Scenic Overlay Roadway Alignment Throughout the development of the corridor alternatives, the landscape architects and transportation engineers have taken curvilinear alignments into consideration when responding to the natural terrain and drainage patterns on the site. The impact of each alignment was evaluated to identify conflicts with natural attributes, and to minimize the area of disturbance to the native desert floor. Transportation Routing Vistas and View Analysis Key features of the property were identified and proposed alignments were evaluated for their ability to capitalize on views of the site s attributes and the scenic vistas. Viewsheds, from the preserve areas to the roadway was evaluated and adjustments were made to minimize the visual intrusion of the future roadway. Slopes The roadway corridor alternatives were evaluated for their impact to adjacent hillsides and slopes. The designers worked closely with the City of Phoenix Parks and Recreation Department staff to develop alignments that would abut existing and future preserve land to serve as a protection buffer. During this process care has been taken to minimize intrusion into the adjacent hillside slopes and to maintain drainage and wildlife corridor patterns. Where cutting of slopes will be necessary, revegetation and aesthetic treatments will be developed for reclamation of the natural hillside slope. Fill slopes will be warped to leave an irregular edge in order to simulate and blend into the terrain of the adjacent existing slopes. Retaining wall and natural material alternatives Where cutting of slopes and hillsides will be required the utilization of natural materials and aesthetic treatments will be employed. Utilization of native stone and boulders incorporated with textured gunite faux stone will be utilized to minimize the appearance of change to the natural terrain and hillsides. staining materials will be utilized to blend the new materials into undisturbed environment. Natural planting pockets will be incorporated into the retaining devices to blend the density of the new vegetation into the natural plant density found in the terrain. Figure 9 illustrates the utilization of

19 natural materials and aesthetic treatments. Re-vegetation Prior to the development of the roadway engineering plans, specific plant material zones should be identified adjacent to the approved corridor route. Plant material selections for each section of roadway will be developed to be utilized in the re-vegetation and development of planting pockets from station to station. Zones for required erosion control re-vegetation, will be evaluated and identified. Plant material will be identified for the incorporation into drainage ways and underpasses. Figure 11 displays the urban and scenic cross sections, with conceptual revegetation. Structure Aesthetic Treatments Aesthetic treatments have been developed for three different types of structures. These include Primary (bridges and overpasses), Secondary (fluted archways and large box culverts) and Tertiary (piping and small box culverts). Figure 10 illustrates primary and secondary crossings, while Figure 11 illustrates tertiary crossings. Alternatives have been developed for the aesthetic treatment of all three types of structures utilizing native materials and a natural color palette. appropriate size structures have been incorporated into the roadway design as not to impede the passage of users or drainage. Coordination of the required human and wildlife usage with the flow requirements of the drainage ways has been done to minimize cost where shared usage can occur. Figure 12 displays conceptual trails, and trailheads in the Sonoran Preserve. Sonoran Preserve Edge Treatment The landscape architects have worked closely with the city staff to develop the roadway corridor to complement the existing Sonoran Preserve Master Edge Plan. Public access points, an interpretive center, regional access points, and a buffer Paseo concept will be incorporated into the buffer edge treatment of the final corridor alignment selected for the parkway. Street Lighting In the preserve area, street lighting will only be provided at intersections, flyovers, and merge/diverge areas. Scenic Overlay The City of Phoenix can place a scenic overlay on the roadway corridors. It will act as zoning and will be the City s method of controlling development along the roadways. Incorporation of Wildlife and Human trails Working closely with the staff from the city s Parks and Recreation Department and the environmental planners the existing human and wildlife pathways and drainage corridors have been identified. The intersection of these paths and drainage ways with the corridor has been identified and

20

21

22

23

24 STRUCTURES OVERVIEW The Sonoran Parkway crosses the Apache Wash on a 0.60% grade. The length of bridge required at this site to pass the 100-yr flood is approximately 860 feet westbound and 850 feet eastbound. The structure depth will be limited to 8 feet to allow freeboard over the predicted water surface of The alternatives for this site include the following: span cast-in-place post-tensioned box girder bridge; for aesthetics the bridge arch could be curved. span precast I-girder bridge with a cast-in-place deck. Sonoran Parkway also crosses Mesquite Tank Wash and Cave Creek Wash. For these sites precast I-girders or cast-in-place concrete box girders will be appropriate options. The box girders lend themselves to better aesthetics. At Mesquite Tank Wash, the span lengths will be 280 feet eastbound and 440 feet westbound. The alternatives for this site include: Eastbound: a two span bridge with 140 foot spans. Westbound: two spans of 220 feet or a three span bridge with 147 foot spans. the appearance of this 1/4 mile long bridge. Dove Valley Road will cross over the Sonoran Parkway as a flyover requiring walls and a 230 foot long bridge structure. Two bridge options can be considered for this site: 2 span precast girder or cast-inplace post-tensioned box girder bridge with spans of 115 feet each and a structure depth of 5 feet; this option also includes 850 feet of wall on each side. 4 span precast girder or cast-inplace box girder bridge with spans of 100 feet on a matching skew with the Parkway; this option reduces the wall to 680 feet on each side. The final bridge location to be discussed is the Tatum Boulevard Connection Flyover. This bridge is on a 4.75 degree curve with a length required of 400 feet. Because of the curve, a two span posttensioned box girder on a curve alignment is the best option. The span lengths would be 200 feet each with a structure depth of 8 feet. Walls will also be required at this site (1050 feet on each side of the approaches). At the Cave Creek Wash a major bridge is required. The span length as proposed to cross the floodplain is 1520 feet westbound and 1435 feet eastbound. Post-tensioned box girders will require the fewest columns feet). Precast girders would require 11 spans of feet each. Careful consideration should be given to

25 PUBLIC MEETING As part of the public participatory process, a second public meeting was held on Tuesday, June 10 th, 2003 at the Paradise Valley Community Center. Notices were sent to the local newspapers, and mailers were sent to an array of people in the community. The meeting was a come and go, open format. A self-running PowerPoint presentation gave an overview of the project at the entrance. Inside the meeting, the public was free to look through the approximately twelve display boards that presented the original alignment alternatives, the preferred north alternative, land ownership, the Sonoran Preserve limits, plan and profile of the most current design, and renderings of the flyovers, the primary and secondary crossings, and tertiary crossings. Approximately 70 people attended the meeting.