We sometimes take for granted the hard work and maintenance required to keep storm water moving in order to prevent flooding at our homes and businesses. History has proven that without efficient systems in place, millions of dollars of damage can occur if the storm water is not effectively transported from impervious surfaces to lakes, rivers, ponds, and/or oceans.
For storm water professionals, the task of inspecting miles of storm water pipelines and associated infrastructure can be very difficult.
Aging systems, frequently built without today’s engineering and construction controls, quite often create problems due to blockages, improper drainage, material deterioration, etc.
Construction materials used were not always the best choice for the environment they were placed in. An example is corrugated metal pipe (CMP) used in a saltwater environment. Corrosive soil, the use of dissimilar metals creating galvanic currents, and other environmental factors all lead to deterioration. Additionally, defective manufacturing materials and methods, improper construction techniques, and construction damage can contribute to problems that may arise in storm water systems. Both corrosion and abrasion of materials transported through the pipes are leading causes of deterioration.
Consequently, thousands of gallons of water are lost in systems each day. Infiltration of groundwater through deteriorating joints and openings in pipes accelerate aging and allow backfill material into the openings. Infiltration also allows unwanted chemical pollutants that are picked up by the groundwater to enter the storm water system, while also being transported to lakes and streams.
The condition of storm water pipes are commonly assessed using closed circuit television inspections (CCTV). This method can be problematic when the pipeline is partially or fully submerged. Quite often, storm water professionals resort to de-watering of the pipe in order to perform a dry inspection. Sometimes these attempts at de-watering are futile due to high volume ground water infiltration into the pipe.
The utilization of Remotely Operated Vehicles (ROV) for underwater inspection services is an essential and cost effective solution. Using an ROV allows the inspection to be done either partially or fully submerged, avoiding inefficient dewatering.
For dry or semi-dry pipes, Glenn Underwater Services, Inc. (GUS) uses “crawlers” (highly agile vehicles with wheels for mobility to navigate through pipes and other confined areas), to inspect any pipe from as small as 4 inches to 10 feet in diameter.
Many companies have CCTV equipped crawlers, but GUS utilizes theirs unique to any other, having it “swim” through the water while using three-dimensional navigation for underwater inspections. Another important quality is its extra long, 3000-foot tether that makes extensive pipeline penetrations possible.
The robotic vehicles can carry an array of inspection equipment. This includes: laser measuring devices, ultrasonic thickness gauges, and high definition video systems.
One of the most useful tools carried by ROV’s piloted by GUS is the multi–beam sonar. This sophisticated tool produces a detailed rendering of the conditions found inside of the pipe. Every joint, spall, debris, and/or other anomalies are vividly depicted by the sonar as the ROV is flown through the pipe. Using this video can be vital to finding any defects in poor water clarity.
All of GUS’ robotic inspection equipment is compact, readily available, and easy to transport to remote locations. GUS’ Robotics division is made up of dedicated ROV pilots, sonar techs, and support crews. They also employ a full time confined space entry team for projects where the ROV or crawlers need to be launched in a space where access is difficult.
Inspection objectives vary with each client, while typically including:
- Location and assessment of changes to previously identified defects
- Mapping and identification of existing structures
- Discovery of unknown branches in pipelines
- Identification of new defects and anomalies such as:
- Breaks and separations in joints
- Spalls and scouring in concrete pipes
- Holes and corrosion in metal pipes
- Groundwater intrusion into the pipes
- Establishment of a baseline for future inspections
- Location of debris and occluded areas.
To the client, the inspection is only as good as the data acquired. GUS utilizes a state of the art computerized Data Archiving and Collection System known as DACS. DACS produces a ready to use digital inspection report complete with detailed photos, video footage, sonar images, and viewing software; all of which are available on a flash drive.
For more information on robotic inspections of submerged storm water systems and Glenn Underwater Services, Inc., please visit our website at: www.glenndiving.com.