We’ve talked about jet boats and the cataraft for hydro survey. Now let’s dig into the set up and the software. Above is the typical setup with the usual pieces: your positional equipment (not limited to simply GPS), the laptop or simply something that can integrate the position and depth data, the depth sounder, and the transducer.
You’ll notice we’re using a Leica 1200 GPS system in the picture but you could use any GPS system or even a robotic total station. A non-robotic total station would not quite do the job and would take an obscene amount of time to complete the survey, flashing back to the 80s and early 90s of hydro survey.
Depth Sounder and Transducer
We’ve used Innerspace single beam survey grade depth sounders for a long time but recently retired our 455 system. We currently use an Ohmex Sonarmite depth sounder. All of our transducers are made by Airmar, even the slightly different transducers for the Sonarmite. Airmar also makes some sensational mounts along with their transducers.
You need something to integrate your depth sounder data and your positional data. We’ve used Panasonic toughbooks and an Amrel Rocky (old school!) but our crew loves the Getac rugged notebooks. Every component connection is trending wireless but it’s still handy to have more than one com port along with plenty of USB ports. The Getac can take a beating, deal with the glare, has a rubber keyboard, and is fast enough. The other notebooks offer the same but we’ve always had a good experience and minimal field problems with the Getac.
There are two other approaches to a data integrator that I’ve seen: using a Trimble GPS Handheld or using the actual depth sounder itself. If you’re using a Trimble GPS handheld, then you’re also using that as your positional device. This would work well on a pond or even a reservoir, where the water surface is constant and easily measured accurately but not where there is significant variation in the water surface elevation (moving upstream and downstream on a river). I would not recommend using the depth sounder as the data integrator (like the Innerspace 455 can do) because the integration of the data starts to become too much of a black box and you almost always lose a lot of your raw data that you might need to see later. In our experience, using the depth sounder to integrate your depth and positional data has been a nightmare.
The industry standard is HYPACK and we’ve been using it since the early ‘00s. Our folks started into hydro survey using our own custom software but it costs too much to maintain. HYPACK has done the job for us and provides beyond what we usually need. HYPACK is still geared towards ocean and coastal hydrography but it does the job for riverine applications and it’s fantastic for reservoirs. In the example above, the user is using set cross sections placed ahead of time in and they are using HYPACK to track to the line, shown at the bottom left. Every other software package that we know of is associated with a specific depth sounder. HYPACK also has extremely good customer support.
What about using a fish finder as a depth sounder? What about a multi-beam system? We’ll discuss these in posts to come. What do you folks use for your data integrator, single beam depth sounder, positional system, or software?