Case study by SPH Engineering · Bathymetry · Mine reclamation
Replacing sonar boats on coal mine reclamation ponds
Patriot Environmental measures the volume of lined water-retention ponds at coal mine reclamation sites in Eastern Texas. After repeated sonar-boat failures in treated water, it switched to a drone-mounted echo sounder from SPH Engineering, with better data and less risk to its crews.
The challenge
Patriot Environmental installs geosynthetics and containment systems. Its volume surveys of lined ponds support reclamation work, water management and environmental compliance. As the surveys grew to ponds of up to 50 acres, the sonar boats it had used became a problem:
- Equipment failures: the boats kept breaking down in chemically treated or reclaimed water, causing delays and costly repairs.
- Safety: launching and recovering boats on steep, slippery, lined slopes put workers at risk.
- Manual effort: crews had to keep walking around the pond to stay in control and in range of the boat.
- Weather: strong Texas winds often stopped boat work altogether.
The solution
The company moved to SPH Engineering's drone-based echo sounder. A DJI M300 carried an ECT 400S echo sounder on a tether below the aircraft, so the drone's electronics stayed clear of the corrosive water. Flights were planned and flown autonomously in UgCS, and operators managed them from one fixed spot.
The results
- The drone collected many more depth points than the boats did, which gave more detailed and useful volume analysis.
- Crews no longer followed the equipment around each pond. Patriot's field survey coordinator, Eric Denson, said that planning a mission and staying on one side of the pond is much easier than steering a boat and walking the whole perimeter.
- People spent less time near hazardous slopes and pond edges.
- Surveys went ahead in higher winds that had forced boat surveys to be postponed or cancelled.
- Less contact with corrosive water meant fewer breakdowns, less downtime and lower maintenance.
Where this applies in India
Lined and chemically harsh ponds are common at Indian mines and plants. The same approach suits:
- water-retention and settling ponds at coal and mineral mines;
- lined ponds at mine closure and reclamation sites;
- effluent, leachate and process-water ponds at industrial plants and landfills;
- sites where wind, steep liners or water chemistry make boats unreliable.
SPH Engineering's bathymetry training is also available through HobiTech.
The equipment, available from HobiTech
| Echo sounder | EchoLogger ECT 400S |
| Flight planning | UgCS - Drone Flight Planning Software |
| Onboard computer | SPH Engineering's drone echo sounder system runs on SkyHub by SPH Engineering with the SkyHub echo sounder software |
| Drone | DJI M300 was used in this project. Ask us for current compatible drones, such as the DJI Matrice 350 RTK. |
Case study by SPH Engineering, published April 2025. This page summarises it in our own words; the surveys were carried out by Patriot Environmental, not by HobiTech. Read the original case study on SPH Engineering ↗
Still surveying ponds by boat?
Tell us the pond sizes, the water conditions and how often you survey. We will specify the drone, echo sounder, SkyHub and UgCS setup, quoted in rupees with a GST invoice.