2025 Storm Sewer Condition Assessment & Rehabilitation Analysis

A comprehensive, multi-phase condition assessment and rehabilitation planning program for approximately 2.6 km of storm sewer infrastructure across multiple sensitive environmental corridors in the City of Grande Prairie.

CLIENT
City of Grande Prairie
PROVINCE
Alberta
TIMELINE
October 2025 - Ongoing
QUICK DETAILS
Contract Type
Engineering & Assessment
Manholes
25 manholes
Total Network
~2.6 km
Inspection
CCTV, LiDAR, UT, hammer sounding, concrete testing, and soil corrosivity assessment

Project Overview

The City of Grande Prairie engaged Avodahtec to complete a comprehensive condition assessment and rehabilitation analysis of its storm sewer network.

The project includes approximately 2.6 km of storm sewer infrastructure with pipe diameters ranging from 300 mm to 2,100 mm, along with 25 associated manholes across multiple sensitive environmental corridors. The large diameter pipes show evidence of invert corrosion, joint separation, and bedding loss — issues that require detailed technical investigation to fully characterize.

The objective is to evaluate the structural integrity and long-term performance of the storm sewer system, identify corrosion and bedding-related risks, and develop data-driven rehabilitation recommendations to support the City’s capital planning program.

Project Scope Snapshot

Storm Sewer Network

2.6 km

Pipe diameters: 300 mm – 2,100 mm
Multiple environmental corridors

Manholes

25

Associated manholes across the full storm sewer network

Inspection Methods

LiDAR

CCTV, UT testing, hammer sounding
Soil corrosivity analysis (AWWA M27)

The Challenge

Large-diameter storm sewer infrastructure can be difficult to assess due to limited access, varying pipe materials, environmental constraints, and complex deterioration mechanisms including invert corrosion, joint separation, and bedding loss.

TECHNICAL CHALLENGE

Evaluating invert corrosion, joint separation, deformation, and bedding loss across varying pipe materials and large diameters — including pipes up to 2,100 mm — while working within multiple sensitive environmental corridors and ravines.

Strategic Challenge

Providing the City with technically defensible, actionable rehabilitation recommendations that balance structural performance, constructability, environmental impact, cost, and hydraulic constraints across diverse asset conditions.

Our Approach

Avodahtec is delivering a structured, multi-phase assessment and rehabilitation planning program:

1. Desktop Review

Reviewed existing CCTV records from 2020–2021, as-built drawings, maintenance records, and available asset data to establish baseline conditions and identify data gaps across the storm sewer network.

2. Site Reconnaissance

Conducted field reviews to confirm access points, right-of-way constraints, environmental considerations, and inspection feasibility near corridors and ravines across the project area.

3. Field Inspection Program

Developed and coordinated advanced inspection and testing programs including LiDAR inspection for ovality and deformation, ultrasonic thickness testing, hammer sounding, concrete testing (Schmidt and spike tests), and soil sampling for external corrosion risk assessment per AWWA M27 and ASTM standards.

4. Condition & Integrity Assessment

Evaluated storm sewer condition by quantifying invert corrosion, joint separation, deformation, bedding integrity, load-bearing capacity, and external corrosion exposure to develop a comprehensive structural assessment of each segment.

5. Rehabilitation Strategy Development

Assessed trenchless rehabilitation options including cured-in-place pipe (CIPP), centrifugally cast concrete pipe (CCCP), sliplining, and invert paving. Prioritized methods based on technical suitability, constructability, cost, hydraulic impact, environmental constraints, and long-term service life using a transparent multi-criteria evaluation framework.

6. Decision-Support Deliverables

Preparing technical reporting, geotagged GIS mapping, condition indices, and prioritized rehabilitation recommendations to support the City’s storm sewer capital planning program with clear, defensible guidance for future investment decisions.

What Made This Project Successful

Proactive Assessment & Planning

Early integration of LiDAR, UT, and soil testing provides a complete, data-driven picture of the storm system’s condition — enabling the City to act before failures occur.

Actionable, Defensible Recommendations

Rehabilitation options are prioritized using a transparent, criteria-based framework that balances technical feasibility, constructability, and cost — providing council with clear, justifiable investment guidance.

Reduced Risk & Lifecycle Cost

Early detection of corrosion and bedding loss enables timely intervention and prevents costly emergency failures, maximizing the long-term value of the City’s storm infrastructure investment.

GIS-Based Decision Support

The City receives geospatial mapping and condition indices to strengthen its long-term capital and asset management programs, with clear visual tools to support ongoing planning.

Collaborative Project Delivery

Regular coordination meetings, clear documentation, and open communication ensure alignment with City staff and smooth execution across all project phases.

PROJECT DETAILS
Type
Public Municipality
Location
City of Grande Prairie, Alberta.
Start
October 2025
Status
Ongoing
SERVICES PROVIDED
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