Costco Storm Water Improvements

PROJECT. Gasoline Alley West (CostcoStorm Water Improvements)

LOCATION.  Liberty Ave, Red Deer

OWNER. Red Deer County


Andrew Treu, Environmental Services Manager

START DATE.  Aug. 2014



TAGISH’S ROLE.  Prime Consultant



Continuing aggressive development in the Gasoline Alley corridor began to influence the West side existing storm water detention and outlet facilities which prompted Red Deer County to initiate a Storm Water Management Study and resultant Storm Water facility and Infrastructure improvements. Tagish Engineering Ltd was commissioned in the summer of 2012 to compile a Stormwater Management Plan for the Liberty subdivision. The main goals of the stormwater management plan were to delineate Primary storm water flow routes and existing infrastructure Pre-Development storage requirements for Liberty Subdivision Post Development storage requirements Liberty Subdivision additional infrastructure required. The solution hinged on improved stormwater collection, transmission and improving the discharge characteristics from the main detention facility, while continuing to protect Waskasoo Creek, which is the systems receiving outlet watercourse This project involved an interconnection between the South ponds (Gasoline Alley) and the Costco Stormwater Facility via 1,180m’s of 600mmø U-Rib Storm pipe was installed to alleviate potential flooding and to maximize the storage capacity.



  • Created an additional 0.4 m storage depth at Pond 1 (South ponds Gasoline Alley), which equates to approximately 16,000 m3 of storage. 

  • Alleviated 1:100 year event and outlets to Waskasoo at 5 l/s/ha

  • Created minor system for Liberty Avenue

  • Corrected slow outlet rate at South Ponds

  • Due to the high volumes of traffic which access the commercial businesses in the Gasoline Alley area, a Detailed and complicated Traffic Accommodation Strategy was developed and implemented which allowed for an aggressive construction timeline while minimizing traffic and surrounding business disruption

  • Small amount of land requirement


  • Poor ground conditions and deep excavations led to challenging construction scenarios which were addressed at each occurrence with innovative field implemented solutions by the Tagish team, that included importing dry clay materials that were placed in at a meter thick below subgrade during the backfill and compaction of the storm trench and with the addition of a Biaxial Geogrid installed between the sub-base and base course gravels provided a solid and cohesive road structure

  • Imperative for surrounding commercial businesses that access was maintained at all times. This was accomplished through an extensive Traffic Accommodation Strategy, continuous interaction with the area businesses, comprehensive signage, and continuous detour monitoring and reconfiguring.

  • Quality Assurance Construction Inspection

  • Liaison with Business owners

  • The project was completed both on time and on budget.



  • Hydrology Analysis

  • Storm Water Management Report

  • Project Scope Definition and Preliminary Design

  • Detailed Engineering Design

  • Traffic Accommodation Strategy

  • Tender Preparation

  • Preliminary and Construction Surveys

  • Contract Administration

  • Project Management

  • Construction Observation and Inspection










© 2016 Tagish Engineering Ltd.

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