The City of Coquitlam had incurred considerable costs to address erosion and related issues in some of its creek watersheds. For planning purposes, the City envisioned developing criteria or condition codes for creeks (similar to CCTV codes and ratings) that could be used to assess, evaluate, and classify risks in certain urban creeks.
Water Street was engaged to explore the potential of completing a city-wide assessment of its creek network by completing a pilot study on sections of Scott Creek and Nelson Creek. The work included developing a high-level creek hazard classification and rating system that would enable the City to evaluate the feasibility of inspecting the creeks by walk-through assessments or using unmanned aerial vehicles (UAVs or drones).
The purpose of the classification and rating system was to identify and rate the severity of bank erosion features, creek blockage features, and sediment transport features. Walk-through and drone assessments of the same creek segments were completed to compare the accuracy and effort involved in each approach. The information collected during the assessments was used to develop a cost estimate for completing the city-wide assessment and to provide recommendations for next steps including the development of a drone specification and assessment process.
The project included numerous challenges. Of particular concern was the large amounts of vegetation that made LIDAR surveys impossible and walk-through and drone surveys difficult, time consuming, and dangerous.