Seven Meadows Subdivision Storm Water Pond

Project Summary

Stormwater Management Pond As-Built Survey for Municipal Transfer

Municipal ownership transfer of stormwater management infrastructure requires precise as-built documentation that meets strict regulatory standards for engineered pond features and sediment management. The Seven Meadows Subdivision stormwater pond project in Beaverton presented IBW Surveyors with the complex challenge of accurately documenting all underwater infrastructure while determining exact sediment volumes for removal planning. This comprehensive bathymetric survey was essential for the client to successfully transfer pond ownership to the municipality, requiring detailed measurements of headwalls, internal berms, inlets, outlets, manholes, and the critical distinction between hard bottom surfaces and accumulated sediment layers.

Technical Details

USV Sonar Integration with Conventional Survey Techniques

The technical execution of this project required innovative approaches to overcome both environmental and technological challenges inherent in underwater surveying. IBW strategically postponed fieldwork until optimal thaw conditions ensured accurate data collection, then deployed an Unmanned Surface Vessel (USV) equipped with survey-grade sonar systems to capture detailed bathymetric data throughout the pond. Since sonar technology cannot penetrate sediment layers to reach hard bottom surfaces, IBW supplemented the USV data collection with conventional rod elevations in critical areas, particularly around engineered structures where precise hard bottom definition was essential for sediment volume calculations. This hybrid approach enabled comprehensive documentation of all pond features while providing the accurate sediment depth measurements required for municipal acceptance and transfer planning.

Equipment & Technology

Kingfisher USV Platform with Integrated Echo Sounder and Processing Suite

IBW utilized a specialized marine surveying technology platform designed for precise stormwater infrastructure documentation requirements. The primary data collection employed a Kingfisher USV equipped with a BL700 Single Beam Echo Sounder for comprehensive underwater mapping, supported by Trimble Robotic Total Stations and Trimble GNSS Systems for precise positioning control and terrestrial feature surveying. All bathymetric and survey data underwent rigorous post-processing through AutoCAD Civil 3D for design integration, Microsurvey CAD for specialized bathymetric calculations, and Trimble Business Centre for comprehensive data management and quality control. This integrated technology approach ensured that all measurements met municipal standards for infrastructure transfer while providing accurate sediment volume calculations essential for pond maintenance planning.