Glenn Highway MP DSR. Landscape Narrative

Transcription

1 Glenn Highway MP DSR Landscape Narrative Project Landscape Goals The Glenn Highway MP Project extends through a variety of landscape types typical to the Matanuska-Susitna Valley. In general, three different types of landscapes are representative of the project corridor. These include natural, rural, and urban landscape types that provide a setting for the existing roadway. Distant vistas of the Chugach Range both for northbound and southbound drivers predominate the overall viewshed. Proposed landscape elements will rely heavily on maintaining the existing character of the landscape through which the roadway passes. In addition, since much of the proposed roadway improvements are located within the Palmer City limits, the Palmer Landscape Ordinance with its related Landscape Appendices (Appendix A through Appendix O) will be used as a basis for proposed landscape solutions. Background and Setting Beginning at the intersection of the Glenn and the Parks Highway, the adjacent landscape is primarily natural with the existing road passing through wetlands followed by an area of native forested ridge. The natural segment represents the shortest landscape segment in terms of the three types of landscapes. The natural landscape segment quickly transitions to a partiallydeveloped segment, the rural landscape segment, with foreground views of roadside land uses including campgrounds, storage facilities and businesses, along with railroad tracks and an unpaved pathway. Existing vegetation and landforms screen many of the views from the road along portions of this segment. Views occasionally open to vistas of distant mountain ranges, primarily the mountains of the Chugach Range driving north and driving south. Views also open briefly to adjacent industrial lands, which include resource extraction areas. South of Inner Spring Loop, at the Palmer City Limits, adjacent uses are still within the rural landscape category, however views of agricultural lands, scattered residential and business land uses predominant. Development is somewhat sparse with large open green spaces providing a foreground setting for the west side of the roadway with a fairly continuous vegetative buffer screening views to the east. Views of the Chugach Range dominate distant vistas in almost a 360-degree viewshed. The rural landscape continues with the approach towards Palmer beginning to include more roadside businesses, with parking lots, buildings and access ways dominating foreground views typically in concentrated pockets of development. The Chugach Range provides an impressive backdrop at the Glenn/Colony intersection, however foreground views of utilities reduce the drama of the mountainous backdrop. Distant views heading south are also impressive with the Chugach Range continuing to dominate the viewshed in that direction. The Glenn/Colony intersection begins to mark the change from the rural landscape to the urban landscape setting. The urban landscape segment continues up to and just beyond West Arctic Avenue. The urban segment is marked by proximate roadside development that includes relatively intense business and residential land uses. Topography is a distinct feature within this segment with steep vegetated slopes bordering the west side of the roadway in many areas. Traffic signals, raised mediums, curb and gutter and paved pathways add to the urban nature of the road. Just beyond West Arctic Avenue, the rural landscape character returns with large stands of native vegetation providing a buffer adjacent to the roadway for much of its length up to Palmer Fishhook Road. Slopes on the west side of portions of this segment are steep and heavily vegetated with native vegetation characteristic of a disturbed landscape. The Palmer City limits end south of the Palmer Fishhook Road.

2 Jurisdictions and Landscape Codes The project is within the Matanuska-Susitna Borough, significant portions are also with the city of Palmer. The Borough uses their 2005 Matanuska-Susitna Comprehensive Development Plan to guide development. The plan includes goals for transportation corridors and references the Long Range Transportation Plan. In addition to the prime transportation goal of creating an integrated surface transportation network that facilitates the efficient movement of people, goods, and services throughout the Borough and region, the plan recognizes the need to allow local communities to refine and tailor projects to their needs. The plan states a desire to connect the Borough s neighborhoods and communities using multi-modal design elements while protecting and enhancing natural resources including the existing diverse land use patterns within the Borough. Matanuska-Susitna Borough Recreational Trails Plan (adopted 2000, amended 2004) provides information as to the Borough s existing and proposed trails. The City of Palmer has a strong planning component, which is iterated in several documents including the Palmer Comprehensive Plan (September 2006). Of note the transportation portion of the plan regarding Glenn Highway Improvements states; In order to meet current and future transportation needs, improve pedestrian circulation east-west across the Glenn, maintain community character, and to improve the entrance to Palmer, the Glenn Highway should be designated as a four-lane, limited-access, boulevard-style arterial with a generous planted median. The City will be responsible for maintaining median plantings. The plan also notes that the Glenn Highway is both a State Scenic Byway and a National Scenic Byway that has a Glenn Highway Scenic Byway Association whom meets regularly to organize improvements and marketing activities. The State Scenic Highway designation and the national designation requirements will be explored as the project progresses. In terms of landscaping the Palmer Landscape Ordinance with its related Landscape Appendices (Appendix A through Appendix O) sets the desired direction for landscape elements within and adjacent to Palmer. The plan identifies special issues that should be considered in the design of landscapes including: snow, wildlife, winds, winter lighting, unique history, and development pressure on agricultural lands. Landscape solutions should recognize and respond to these issues through appropriate design. According to the plan, relevant ideas may include providing winter cities design elements (snow storage/removal, recreation options, safe pedestrian crossings, planting strips incorporating storm water treatment), plants that deter wildlife, plantings to create windbreaks, pedestrian lighting, and acknowledgement of Palmer s setting, views and natural beauty. The Appendices note the importance of Complete Streets, a national program recognizing that streets provide services for more than just vehicle travel. Relevant elements according to the Palmer plan would include accommodating pedestrians and cyclists and providing an overall aesthetic appeal to proposed improvements. Appendix E of the Palmer Landscape Ordinance poses the desire for gateways. According to the plan, within the project corridor three types of gateways are suggested. Primary, secondary and tertiary gateways each have different design elements with varying amounts of landscaping, signage, and amenities. The plan calls for a primary gateway at the intersection of the Palmer Wasilla Highway; four secondary gateways located one each at the southern city limits, intersection of Colony, intersection of Arctic Avenue, and the fourth secondary gateway at the intersection of Marsh Road. A tertiary gateway is noted at the intersection with Inner Spring Loop. See Figure 1. In addition to gateways, Appendix E also notes requirements for design elements for road corridors throughout Palmer. Design elements are described in the plan by type of roadway section. The Glenn Highway project includes three roadway sections (types 1, 2 and 5) each with specific design elements. Design elements include number of lanes; need for sidewalk/trails, minimum sidewalk width; need for street trees; need for a center median and

3 related median elements; and minimum planting strip widths. See Table 1, Figure L-1 for project specific requirements. Appendix I notes the need to maintain clear vision triangles at intersections. The plan requires a 30-foot right triangle be kept clear of obstacles, with the 30-foot measurement beginning at the edge of the road and extending along each roadway frontage, the hypotenuse may or may not be within the right-of-way. The proposed project will also use clear vision triangles based on ASHTO standards. Clear vision triangles per AASHTO will be shown on final landscape plans. Appendix J includes requirements for Low Impact Development and storm water management. Design strategies include bio-swales (integrating runoff/bio-retention), planted detention basins (bio-cells/grass swales) reduction of impervious surfaces including porous paving, lengthening flow ways to extend runoff time and improve water storage, infiltration, and groundwater recharge. The plan notes the importance of protecting and preserving environmentally sensitive sites including wetlands and waterways. Appendices K through M provide summaries for plan review information, sample landscape drawings, details for planting and related information. The remaining two appendices (Appendix N and O) list approved plants and prohibited species noting some flexibility in the lists. Proposed Design The proposed landscape plan will be based on existing landscapes along the length of the corridor by enhancing views, retaining open spaces and natural areas where possible and where practical, screening and buffering undesirable views, protecting existing vegetation stands that are critical to adjacent land uses, and creating and enhancing urban portions within the corridor. In general these design goals meet City of Palmer Landscape Ordinances and appendices and to the extent practical the ordinances and appendices will be followed. An early planning meeting to discuss landscaping with city officials included the following design ideas: Pedestrian overpass needed at station /- to connect recreation and schools to residential areas on opposite side of the road. The overpass could be located on existing City-owned land. It would be good to take advantage of grades and reduce use of steps if possible. Use draft documents including Commercial Corridor Plan and Landscape Ordinance (Sandra to provide). The wider the median the better especially at Colony where the median and gateway will be important. Trees are desired in the median if curbs can be provided. Use of lilacs in the median could be a good design element. Commercial nodes are likely to occur at intersections. Decorative fencing is good, however spacing is critical between fencing and light fixtures to avoid maintenance issues. The City does not have small sidewalk sized snowplows (as does Anchorage), which should be considered in placement of trails and landscaping. The intersection at Colony should be a significant gateway. Future elimination/relocation of the electrical utilities/mea substation at Colony may occur. Lighting at the Colony gateway should be pedestrian scale. Wall patterns matching the walls at Crusey Road would be good. Snow plowing of planted median is difficult, plant spacing could make maintenance easier by grouping plants and allowing spaces in between groups for snow storage.

4 Even though the City of Palmer has agreed to maintain medians, extensive landscaping in medians impedes roadway snow removal and storage. Hampering snow operations can create a hazardous situation for roadway users and can also result in driver delays. As design progresses these ideas will be refined and landscape plans will be developed using as many ideas as possible. For overall design concepts see Figure 2.

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