Hwy 2A Storm Water Improvements
PROJECT. Highway 2A Storm Water Improvements
LOCATION. Town of Innisfail, AB
OWNER. Town of Innisfail
Director of Planning and Operations
START DATE. August 2013
COMPLETION DATE. October 2013
CONSTRUCTION COST. $1.1 Million
TAGISH’S ROLE. Prime Consultant
Residents located along Highway 2A through the Town of Innisfail have experienced a significantly high ground water table for a number of years. The need for constant ground water pumping, by means of sump pumps, became a regular occurrence for these residents. Tagish Engineering was commissioned to first assess the situation for possible causes, and then to develop and construct a solution to the problem. Initial site evaluations found that the area was depending on a less than adequate storm water system, and that the area’s grading did not allow for proper drainage. It was derived that an upsizing of the storm water system, in conjunction the installation of ground water drainage basins and improved area drainage, would control surface storm water and lower the ground water table for the area.
The improved storm water system was uniquely designed to allow significant storm water flows (well beyond standard storm water design) to pass underground. It was evaluated that for the overall project, it would be more cost-effective to transfer significantly high rain fall event storm waters underground through the piping system rather than completing a significant amount of surface grading required to provide an overland drainage route as is more commonly used.
Due to the high volumes of traffic which pass through the Highway 2A and 50th Street intersection in Innisfail each day, closing of the intersection for construction was impractical. Along with a few unique construction techniques, a Traffic Accommodation Strategy was prepared and approved through Alberta Transportation allowing for an aggressive construction timeline while traffic continued to flow.
The crossing of a major roadway in Innisfail was required for the storm water system improvement. 50th Street at this crossing location is a five (5) lane elevated roadway which would have required a significant investment and traffic disruption to open cut trench. Auger boring was utilized to allow for a graded pipe installation seven (7) meters below the surface of the roadway while maintaining full use of the roadway. As steel pipe would not be the ideal material for storm water transmission due to rusting, an anode bed was installed to compensate which included a testing station allowing the Town to check the anode bed occasionally over its life span.
Consistent field inspection of the trench zone materials and their characteristics allowed Tagish Engineering to install ideally located ground water drainage basins. The goal of these basins was to allow ground water flows to enter the system instead of building up, hopefully relieving residents from year round sump pump operation. Upon completion of the project, the storm water system maintained a constant outflow of water for the months following until winter freezing. This indicates the ground water table was successfully connected to the storm water system and a drop in ground water is anticipated to occur over the next few years.
Consistent field inspection of the trench zone materials and their characteristics allowed Tagish Engineering to install ideally located ground water drainage basins. The goal of these basins was to allow ground water flows to enter the system.
Initial Project Review and Analysis
Project Scope Definition and Preliminary Design
Detailed Engineering Design
Obtaining proper Provincial and Municipal Approvals
Prepared a Traffic Accommodation Strategy
Performed all Preliminary and Construction Surveys
Construction Observation and Inspection