Mapping storm ponds and wetlands that crews cannot reach

The challenge

Urban Systems wanted to map, measure and inspect inland storm ponds and wetlands. Many of the sites had rugged terrain and limited access, so conventional survey methods were impractical. The firm needed a way to collect accurate data there, reduce costs and finish surveys faster.

The solution

SPH Engineering supplied its integrated echo sounder system. It combines a dual-frequency EchoLogger ECT D052S echo sounder with the SkyHub onboard computer and True Terrain Following.

• The echo sounder uses sonar to measure depth precisely, even in difficult underwater conditions.
• True Terrain Following keeps the drone at a steady height as the surface elevation changes, so measurements continue without gaps.
• SkyHub flies autonomous missions along preset waypoints and tows the echo sounder through the water at 0.7–0.9 m/s. Less manual control means more consistent data.

The result

SPH Engineering reports these outcomes for the client:

• lower costs, because autonomous missions removed manual work in hazardous or hard-to-reach areas;
• shorter surveys than traditional methods would have needed on this terrain;
• accurate depth data from the dual-frequency echo sounder and terrain-following altimeter working together;
• access to locations that could not be surveyed before.

The survey data was used to build a 3D model of the pond bottom.

Where this applies in India

The same workflow suits small water bodies where launching a boat is difficult or unsafe:

• stormwater detention ponds in townships, industrial parks and along highways;
• wetlands and lakes with soft, steep or overgrown banks;
• village tanks and small reservoirs that need depth and capacity checks;
• environmental baseline and monitoring surveys by consultants.

SPH Engineering's bathymetry training is also available through HobiTech.

The equipment, available from HobiTech

Echo sounder	EchoLogger ECT D052S
Onboard computer	SkyHub by SPH Engineering with the SkyHub echo sounder software
Terrain following	True Terrain Following software package for SkyHub
Drone	The case study does not name the drone. Ask us for current compatible drones.

Case study by SPH Engineering, published October 2023. This page summarises it in our own words; the survey was carried out by Urban Systems Ltd., not by HobiTech. Read the original case study on SPH Engineering ↗