Our extensive drainage experience includes hydrologic and hydraulic studies, floodplain delineations, map revisions through the Federal Emergency Management Agency (FEMA), storm water management, detention/retention system design and reservoir routing, Jurisdictional Delineations & 404 Permitting through the Army Corps of Engineers (ACOE), and development of Storm Water Pollution Prevision Plans (SWPPP) for erosion control.
We are always responsible for drainage design on every residential, commercial and industrial project we are involved with. This usually includes hydrology and hydraulic analysis, storm drain design and detention facility evaluation.
Williamson Valley Road Floodplain Analysis
GBE provided professional services to the City of Prescott for this floodplain delineation project funded by the Yavapai County Flood Control District.
The study reach parallels the west side of Williamson Valley Road between Shadow Valley Ranch Road and Standing Rock Drive and is approximately 2,167-ft in length.
The purpose of the study was to determine floodplain elevations along the study reach and recommend drainage improvements to mitigate flooding of adjacent residential structures.
Coyote Wash Stream Restoration Plan
GBE provided professional engineering services for this project that included stream restoration for Coyote wash.
The design included restoration of the equilibrium channel slope. An old stock tank located near the bottom of the reach had raised the channel of the streambed and had created large variations in the energy grade line, causing channel instability and high scour potential.
The design included excavations of the channel flowline of over 10 feet. The project restored the equilibrium slope of the watercourse and lowered base flood elevations significantly.
Scissor Tank Dam Breach Analysis
GBE provided professional services for this project that consisted of a breach design to remove the dam from its jurisdictional designation by the Arizona Department of Water Resources (ADWR).
The breach was designed to reduce the volume of the existing 163 acre-ft reservoir to below the 50 acre-ft mandated by ADWR. The work included evaluation of stage-storage-outflow relationships for the reservoir, inflow hydrology, reservoir routing, scour analysis and hydraulic analysis of the breach.
Smoke Tree Lane Drainage Improvements
GBE provided professional services to the City of Prescott for this capital improvement project funded by the Yavapai County Flood Control District. The project included evaluation of pavement drainage and outfall conditions along the north end of Smoke Tree Lane.
Previously, there was inadequate release of pavement drainage from the roadway. Excess runoff overtops the curb and impacted an adjacent property along the west side of Smoke Tree Lane.
The intent of this project was to design and construct a new pavement drainage outfall structure along the west side of Smoke Tree Lane just upstream from the problem area. This new outfall structure drains directly to the watercourse paralleling the west side of the road.