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engineers watching system monitors

Using Latest Technologies to Maintain Region’s Water Infrastructure

The Water Authority operates and maintains a regional water delivery system capable of delivering more than 900 million gallons of water per day. The system consists of 310 miles of large-diameter pipeline, 1,600 aqueduct-related structures, and approximately 100 metering/flow control facilities. It also includes a state-of-the-art water treatment plant, hydroelectric facilities, pump stations, flow regulatory structures, and a dam with a 24,000 acre-foot reservoir.

Portions of the Water Authority delivery system are several decades old. As assets naturally age, it is critical to actively replace and repair them to minimize service impacts to member agencies or the public.

The asset management team uses the latest inspection technologies to detect age-related defects that might be occurring on pipelines and other water conveyance facilities. By identifying defects early, they can often be corrected using localized, low-cost repair methods prior to them becoming larger, more costly issues. Below are examples of the innovative technologies used by the asset management team.

Close Monitoring

The asset management program’s mission is to rehabilitate assets before problems occur that cause disruptions in service. The program also seeks to extend the life of assets in good condition.

Water Authority staff maintain a comprehensive inventory of all assets, which includes detailed information about location, condition, performance and useful life. Routine assessments include visual inspections, internal/external inspections, steel thickness measurements and real-time cathodic protection data.

In addition, the Water Authority uses the most current technologies for monitoring large-diameter pipelines, including electromagnetic scanning, which detects and locates damaged areas within pipeline walls, and real-time acoustic fiber-optic monitoring, which can detect and locate distress on pipelines while they are in service. Recently, the asset management program identified several large-diameter pipeline sections that were nearing the end of their service life. Rather than abandoning or replacing the pipelines, the Water Authority has been actively repairing them by inserting steel liners. This extends the life of the pipeline without major disruptions to the local community and reduces the cost of replacement.

Electromagnetic Technologies

The asset management team uses a variety of electromagnetic inspection technologies, each designed to assess different parts of the region’s water infrastructure. From inspecting 40 miles of pipelines using Magnetic Flux Leakage in just five years, to overcoming access restraints utilizing an inflatable Remote Field Technology device, staff are dedicated to ensuring the most life is realized by all assets.

Robotic Inspections

On occasion, technologies adapted from other specialized industries, such as oil and gas, are required to inspect pipelines. In 2019 and 2020, inspection technologies including LASER Profilometry and EMAT (Electromagnetic Acoustic Transfer), were robotically deployed in almost three miles of 48-inch diameter steel pipe. The pipeline was in the midst of a recoating project, thereby allowing the inspection of the bare steel interior surface by the highly sensitive technologies not normally seen on coated water pipelines.

3D Tunnel Inspections

The asset management team recently completed a 3D scan of some of its most critical water tunnels.

Cross-sectional view of a bifurcation structure at one of the tunnels. To the left of the image the First Aqueduct Pipelines merge with the tunnel which is on the right side of the image. In the center is the access structure showing the vent on top, the temporary ladder for personnel access, and even a “selfie” of the 3D scanning tool in position.

Why 3D Scans? 3D scanning can create high-precision 3D models of real-world objects, in our case the treated water tunnels. A 3D scanner is transported into the drained tunnels and takes multiple snapshots of the interior. The snapshots are then stitched into a 3D model, an exact three-dimensional copy of the tunnels, which you can rotate and view from different angles on your computer. The 3D scans provide a reading every ¼-inch, creating a point cloud with hundreds of thousands of points; each point having a known spatial x-y-z coordinate. The 3D scans were then coupled with high resolution 360-degree photographs to enhance interpreting and using results. The data is hosted in a web portal for easy viewing and downloading.

Interior view of the tunnel, showing the ‘horseshoe’ shape of the tunnel walls.

How do we plan to use the data? The 3D scans performed in December 2020 will serve as our baseline tunnel geometry. As concrete tunnels age, their susceptibility to developing defects can increase, thereby presenting operational risks. Subsequent 3D scans will be used to do comparative analysis. A computer software will compare a point cloud versus another point cloud; comparing hundreds of thousands of points against each other. The comparative analysis will be able to detect issues and anomalies not detectable by the human eye. Additionally, the 3D scans can be used in future CIP projects, specifically in the design and construction phases of rehabilitation efforts.