Abyss – Underwater Sewerage Inspection

The Issue at Urban Utilities

The Norman Creek siphon (Brisbane, Australia) was refurbished in approx. 1974.? It is designed to transport sewage under the Brisbane River into the S1 trunk system to Eagle Farm Pump Station, and then on to the Luggage Point Sewage Treatment Plant.?

The siphon runs under the Brisbane River from Norman Creek to New Farm, and comprises two concrete shafts which run deep underground with the horizontal section beneath the Brisbane River approximately 318 metres long (1,043 feet). The current water levels are approximately 36 meters-39 meters (118-128 feet) below the access point.

The siphon is currently filled with potable water, instead of being in its dry state.? As a result, the asset cannot be inspected via traditional means. The condition of this asset is unknown, and sending divers to inspect the asset presents a significant safety risk.

The Solution

Deploy a ROUV to capture closed-circuit television (CCTV) footage and still images of the asset.

The Pilot

The pilot was conducted in two phases. Phase 1 was an exploratory activity to determine the feasibility of deploying a tethered drone into the siphon. Phase 2 included:

  • Internal inspection of the siphon through the provision of tethered drone
  • Location/identification of interesting features/features of concern
  • Condition of internal fixtures and features
  • Detection of ingress points
  • Condition assessment report
  • 3D model

Pilot Results

Urban Utilities invested approximately AUD70,000 (USD42,000) of which 50% was funded under arrangements delivered in the Grant Deed between the State of Queensland and State of Nevada.

The underwater inspection was undertaken using a submersible fitted with the Abyss Solutions imaging technology, which comprises a computer vision camera, integrated lighting, and data capturing software. This allowed high-fidelity data representation in turbid and low light environments. A site inspection was undertaken to determine access conditions and water quality parameters.

The submersible was lowered down two access shafts and controlled through a tether by a pilot located on the surface. The submersible navigated along the obvert of the tunnel, with a downward-facing camera that captured high fidelity images of the visible surfaces of the twin pipelines.

Abyss Solutions delivered the outcomes of the inspection via a web-based database. The database houses:

  • siphon characteristics, including:
    • details (location, location coordinates, length, and diameter)
    • construction profile
    • access profile
  • inspection details (date, time, team, weather conditions)
  • scoring guide/legend
  • overall siphon condition score

Abyss Solutions also provided a condition assessment and score for individual elements:

  • tunnel walls
  • mild Steel Cement Lined (MSCL) pipes & protective coating
  • pipe supports
  • submarine cable

A multi-criteria condition assessment based on the IPWEA Condition Assessment & Asset Performance Guidelines was applied. Each element was assigned a condition grade ranging from ?0-not rated? to ?5-very poor?. A weighted average used to assign the overall reservoir condition.

Abyss Solutions also constructed a 3D digital model showing the internal configuration of the siphon. The model was produced using data from the inspection and includes annotations. The method of delivery via a portal exceeded expectations.

Further Adoption

The adoption of this technology as a business-as-usual solution is under consideration.

About the Technology

Abyss Solutions, located in Sydney, Australia was founded by four scientists and engineers from The University of Sydney in 2014. Abyss is a robotics company that combines the latest innovations ROUVs with state of the art data analytics to provide a safer, easier, and more comprehensive underwater inspection, allowing for correct asset management decisions.




The Issue Facing Southern Nevada Water Authority

In the efforts to maintain Southern Nevada’s precious water resources, The Southern Nevada Water Authority (SNWA) needs to conduct assessments of its major infrastructure and water intake systems to understand their condition and identify any repairs or upgrades that might be needed. Reaching and providing high quality imagery in areas such as Lake Mead can be challenging because of the depth of the intakes.

SNWA partnered with Abyss Solutions to conduct comprehensive assessments of three water intakes at Lake Mead and a standalone reservoir facility. Abyss Solutions is a robotic infrastructure assessment and management company based in Australia.

“Lake Mead and Hoover Dam are like American icons,” said Abyss Solutions company Director and COO Masood Naqshbandi. “The main challenge there is working at that depth. We were at 60 meters plus underwater. We had to customize our rig to get to those depths. We wanted to get a good understanding of the structure.”

Result of Pilot

The underwater inspection and condition assessment of the Lake Mead intakes functioned to gauge the structural integrity and extent of invasive quagga mussel growth in the intakes. Utilizing Abyss’ remotely operated vehicle controlled from a sampling vessel, the company surveyed each intake in mid-April, 2018, collecting more than 6,000 photo representations of the structures. The images were then evaluated and enhanced off site with algorithms to ensure true-color details and other finer points were visible. Three-dimensional depictions of certain faults and points of interest were also produced, while fault analysis allowed for examination of potential structural defects including corrosion, deformation and fractures within the intakes’ infrastructure. The condition of the intakes was then judged utilizing standards from the 2001 edition of the “ASCE Underwater Investigations Standard Practice Manual.”

Abyss found two out of three of the intakes to be in good condition. One of the two, which was inoperative at the time of inspection, had no visible damage though its structure had minor deterioration. No repairs were recommended, but a coating of quagga mussels at least 5/8 of an inch thick suggested a need for continuing monitoring and treatment of the region. The second “good” intake system showed a light layer of quagga mussels and apparent minor corrosion discoloration at a weld spot. Abyss suggested further investigation of the seeming damage at that spot as well as continuing quagga mussel treatment and observation.

A third intake system, which like the first is also currently out of use, was reported to be in fair condition due to apparent corrosion discoloration on screen support members. Abyss recommended repair of that problem should the intake system be put back into use, and it also suggested continuing quagga mussel assessment and treatment for this region as well, due to two or three dense layers of the invasive species across the structure.

Three-dimensional images of certain points of interest provided the water district with an even more advanced ability to assess the structure as a whole, with zoom and rotation abilities as well as clickable annotations.

The SNWA has put into effect treatments to keep the nonnative quagga mussels from colonizing its water infrastructure, and the results of Abyss’ work show those vital measures have been successful so far, said SNWA and Las Vegas Valley Water District spokesman Bronson Mack. “We’re very interested in advancing water technology for ourselves and for the water industry as a whole,” he said. “That high-fidelity imaging tells us that the system is working as it was intended.”

The technology used to assess the intakes also delved into a standalone reservoir, and a three-dimensional analysis of the system was compiled for engineers and other officials at SNWA, offering a complete portrait of the state of the structure. Through both assessments, Abyss Solutions provided the Southern Nevada agency with early access to an innovative and relatively low-cost technology. The remotely operated vehicles provide a smaller-scale alternative to massive machines with an enormous cost of operation and purchase.

Further Positive Impacts in Southern Nevada and Beyond

While in the country, the company also did a pilot with the U.S. Coast Guard, and its technology is being piloted in cooperation with oil and natural gas companies in the Middle East. It is also piloting its algorithms in the United Kingdom. Such projects will expand the knowledge base of the Abyss crews involved and allow them to better test and refine the technology they use in Nevada and abroad.

“We need water tech here,” said WaterStart Chief Executive Officer, Nathan Allen. “We have the smallest share of water in the Colorado River. We’re the driest state in the U.S. – always have been and always will be. The big benefit is that we reduce the risk of trying new things. By leveraging outside monies from the state or private interests to support pilots, our members are able to spend less money. The amount of red tape they have to navigate to try something new is reduced.”

Abyss Solutions has made Nevada its home base in the Western United States as a result of its partnership with WaterStart. It is now seeking additional work in the region in order to secure a full-time presence in Nevada. The company is in the process of discussions with the Las Vegas Valley Water District to arrange inspections of groundwater wells and reservoirs, providing a cost-effective manner of comprehensively monitoring vital water assets in the region.

About the Abyss Solutions Technology

Abyss Solutions is a robotic infrastructure assessment and management company based in Australia. Founded by a group of four academic researchers and advanced-degree students at the University of Sydney in 2014, the company offers water resource managers a detailed appraisal of the condition and environment of their underwater infrastructure with cutting-edge technology. Utilizing a remotely operated vehicle, a high-fidelity imaging system and a refined data analysis process, Abyss captures visual, acoustic and location data from the infrastructure. The company can then interpret the collected data to generate three-dimensional models of such systems, assessments of quality/condition and periodic evaluations of changes in the infrastructure over time.