EPG, together with the District, the City of Mesa, MCDOT, and the project team, recently completed the design of the McDowell Road Basin and Storm Drain project located in Mesa, Arizona. The project, identified in the Spook Hill ADMP, included the design of a storm drain system in McDowell Road that flows west from the intersection of McDowell and Hawes Roads to the Las Sendas Channel located west of Sossaman Road, where flows will continue ultimately discharging into the Spook Hill Flood Retarding Structure. Storm flows at or near the 100-year storm event will be diverted by a splitter structure into an off-line detention basin located at the southwest corner of McDowell and Sossaman Roads. EPG’s principal role was to assist the project team in the design of the storm drain and basin to follow the landscape and design considerations identified in the Spook Hill ADMP and to be responsive to the characteristics of the project area. Specifically, the ADMP identified natural and physical characteristics of the area, including the regional and local setting, geology, ecology, and visual resources, as well as a landscape design theme and design considerations and guidelines for the proposed basin.

• provide a perimeter landscape buffer around the basin
• create an overall form that appears more organic and less geometric
• warp and vary side slopes in an irregular pattern
• undulate the bottom of the basin following the natural topography of the site
• round the top of basin side slopes
• use vegetation from the City of Mesa’s Upland Development Standards
• scatter vegetation along both sides of the operation and maintenance road
• place shrubs, groundcovers, rocks, and boulders in an irregular pattern along the sides and top of the basin side slopes
• consider views from McDowell Road, 76th Street, and the Las Sendas development
• install a temporary irrigation system to establish plant material
• use materials, shapes, and colors for structural components that blend with, and are native to, the surroundings
  

As a part of this effort, EPG conducted an assessment of the scenic resources of the basin site including an analysis of the site’s Visual Sensitivity (including sensitivity from residential, vehicular, and pedestrian viewing areas), Landscape Character, and Scenic Quality (including an analysis of vegetation, hydrology, and landform). This assessment, together with the considerations and guidelines identified in the Spook Hill ADMP, the input and comments received from the community, and comments received through facilitation of a Project Aesthetic Advisory Committee was used in developing the final design for the basin. Ultimately, EPG prepared the conceptual grading design and planting and irrigation construction documents for the basin site.