Shallow Groundwater Mitigation Images: Left: A subsurface collection gallery, consisting of a drain pipe, surrounded by drain rock and a geotextile is apparent in this image. Right: The collection gallery is being set into place by the construction crew.
Shallow Groundwater Mitigation, Boise, ID
In mid-summer 2011, Ada County Drainage District No.3 (DD3) was contacted concerning surface water that was noticed in a handful of residential backyards in Boise, ID. These homes were located within the service area of DD3.
A task force composed of DD3 and others was formed to immediately observe the situation. In the fall of 2011, the charge of the task force was refined to develop a potential solution to the situation.
Quadrant Consulting, acting in the capacity as the District Engineer for DD3, provided surveying and engineering support for the task force. QCI established project horizontal and vertical control on a known datum; conducted a site topographic survey, including cross sections; imported existing topographic mapping for the area; and, using Autodesk AutoCAD 2012 Civil 3D, developed a project surface for planning and design purposes. In addition to the local topographic work, QCI also correlated data from existing groundwater monitoring wells, and then developed a highwater surface model for the area surrounding the site.
Following the field surveying, QCI, working closely with the task force, developed preliminary and final construction plans for a subsurface collection system and pumped gallery system. QCI also worked closely with the affected neighbors to develop a plan designed to minimize the inconvenience of construction and disruptions associated with heavy equipment is relatively small backyards. QCI provided construction control and the project was completed in early-Spring, 2012. Throughout the life of the project, QCI staff demonstrated an ability to respond on short notice and to provide the task force members and with quality data, surveying and design products.