Civiltec was selected to complete the Ho Kay Gan ADMS in September 2015. The Ho Kay Gan ADMS area is approximately 300 acres in unincorporated Yavapai County. The study area is entirely residential and essentially “built-out.” The study area is generally located west of Williamson Valley Road, south of the intersection of Williamson Valley Road and Pioneer Parkway near the City of Prescott. The Ho Kay Gan area has been subject to historic drainage and flooding problems: the latest significant flooding occurred in September of 2013.
This project included new two dimensional hydrologic and hydraulic modeling for the 1.5-square-mile watershed impacting the study area including significant existing drainage structures. Based on the modeling and input from local residents through mailed questionnaires and public meetings, problem areas were identified and quantified for various storm event recurrence intervals. Civiltec developed conceptual alternatives and preliminary cost estimates to mitigate drainage and flooding problems in the study area. Based on a set of criteria developed by the project team, conceptual alternatives for the various problem areas were recommended throughout the study area. The conceptual mitigation measures for the alternatives were then prioritized based on a weighted prioritization matrix. The recommended alternatives will be further developed into construction plans and documents subsequent to the ADMS. The selected conceptual alternatives included regional detention, storm drain improvements, and roadway crossing improvements.
Civiltec was recently selected to provide surveying and engineering services for the first three design projects identified in the Ho Kay Gan ADMS.
1. Burnt Ranch Road Improvements Project
The Burnt Ranch Road crossing improvements just west of Williamson Valley Road will be designed as a 49-inch by 33-inch CMPA with inlet/outlet cutoff walls, an inlet/outlet reinforced concrete throat with rip-rap blanket, and headwall modifications. The existing two 40-inch by 29-inch CMPAs will remain in place. Additional tasks for this project includes utility coordination and potholing, hydraulic calculations, three legal descriptions and easement documents, geotechnical investigation, and full construction documents (plans, specification, and cost estimate).
2. Ho Kay Gan Subdivision Storm Drain Improvement Projects
The project area is shown below. Civiltec will design roadway improvement plans for the portions of Hozoni Road and Yampa Drive as shown in red and storm drain and road improvements for the portions of Yampa Drive, Chichicoi Lane, Kachina Drive, and Hozoni Road as shown in green.
The improvements will consist of storm drain ranging in diameter from 24 to 54 inches, manholes, inlet/outlet structures, pavement reconstruction, and minor roadside ditch grading within the northeastern portion of the subdivision, as a viable means for reducing the flood hazard to lots and homes in this area. Additional tasks for this project includes utility coordination and potholing, drainage report, 10 legal descriptions and easement documents, geotechnical investigation, and full construction documents (plans, specification, and cost estimate).
3. Regional Detention Facility Project
Civiltec will design a detention facility, outlet pipe and spillway, and a drainage pipe crossing Williamson Valley Road as a viable means for reducing the flood hazard to both the Ho Kay Gan neighborhood to the south of the facility and the residential lots south of Southview Drive. The location of the detention facility is north of APN 106-26-108 (Liberty Baptist Church of Prescott) and west of Williamson Valley Road on Arizona State Land. This project will require contact with the State Land Department for right of entry and close coordination during the State Land Easement application process.
Additional tasks for this project include: utility coordination and potholing, hydraulic calculations, 1 legal description and easement, geotechnical investigation, archeological clearance, Pre Construction Notification for a Nationwide Permit 43 Stormwater Management Facilities, and full construction documents (plans, specification, and cost estimate).