Hydrographic surveyingPosted by just-a-surveyor on August 11, 2019 at 10:25 am
I have seen and been involved in some Hydrographic jobs when I was with the power company and they had their own boats for sounding the rivers and ash ponds. These were 20 foot boats with lots of equipment on them.
The only other time I did anything remotely similar was about 25 years and we used a row boat and a level road to reach the bottom of a pond to take shots to see if it had been silted in.
I’ve always kinda been interested in that kind of work but help me out here, what is your market? Who do you do these jobs for and for what purpose?
- 14 Replies
- MemberAugust 11, 2019 at 1:28 pm
Sewer lagoons count? Been in far too many of them.
One winter I drilled through 24in of ice to get water depths for an aerial lidar project.
- MemberAugust 11, 2019 at 1:39 pm
For several years, we did the detention ponds at a coal fired power plant. They wanted to see how much coal particulate was making it into the ponds. We started by trying the level rod and a boat, but the ponds were too big to keep any sort of system. We ended up using a GPS system with a bottom sonar for depth mounted on an amphibious atv which helped when we ran aground. We also have done surveys for a couple of local lakes that wanted to dredge out the sediment, a before and after type thing. We used the GPS and sonar for them also.
- MemberAugust 11, 2019 at 1:49 pm
I’m thinking about the small catamaran style boats with a depth sounder that have a gps receiver on it. None of that level rod stuff.
The power plants are out of consideration because around here they do their own soundings. Never seen a sewer lagoon unless you’re describing a waste water treatment plant.
I am not aware of a need for this kind of work for retentiondetention ponds because with very few exceptions they do not hold water for long so you can usually walk the bottom.
So that still leaves me wondering where is the market for this kind of work?
- MemberAugust 11, 2019 at 3:35 pm
My former employer did a lot of transportation work, including bridges of varying sizes. Every time you fiddle with a crossing of any size, a hydrographic survey is needed.
We used a sungle beam sonar on a snall aluminum boat. We started with a used 8 hp motor from a rental outfit. We learned (quickly and painfully) that dependability was important. It’s simply too inexpensive to do it any other way than right.
Creeks, streams and rivers vary widely with geography. Get what’s safe for your conditions. The sonar takes about 5 minutes to learn and two or three jobs to get very comfortable. We invested about 3 grand in everything and used it 10 percent of the time. If you provide the service to transportation engineers there are places you can make a very comfortable living.
- MemberAugust 11, 2019 at 5:10 pm
I have made a few hydro surveys in the 1980s of intake lagoons and lakes and drainage areas for the client to compare to the original underwater layout to calculate the amount of sediment that has accumulated or erosion that has occurred.
I stayed away from contaminant sediment ponds as they usually contain elements that were hazardous to your health and would deteriorate the craft.
We used a flatbottom boat and read the tape with a weight on the end and coordinated using a TS tracking shot to a prism mounted on the bow at the place of measurement and radioed to the IMan that would note the depth in the descriptor.
- MemberAugust 11, 2019 at 5:32 pm
I do a few dredging surveys a year for small boat harbors.
- MemberAugust 11, 2019 at 7:18 pm
Murphy’s Law was written for aquatic adventures.
- MemberAugust 12, 2019 at 12:23 pm
It’s a function of where you live and what you specialize in; no shortage of hydro work down here. But if it’s not your area of expertise, a Sonarmite will still do a good job on the occasional small project that might come up and they don’t cost much. Sea Robotics makes by far the best automated catamaran style boat I’ve seen, but that’s a big boy hydro toy – you’re well into six figures for even a basic side scan system.
- MemberAugust 12, 2019 at 2:40 pm
We occasionally had to use sonar for river work, usually for discharge/dispersion calcs. I am also a fan of the Sonarmites, when they work. The single-beam sounders are generally pretty easy to set up and connect to controllers. They are the way to go for basic cross-section work.
However, the downside of single-beam is that it can be sketchy under certain circumstances. Extreme turbidity and silty bottoms can affect precision, and they tend to perform poorly in shallow areas – sometimes I would see “bottom” shots that were higher than the water level.
All we had was a 2×4 bolted on to the seat of a Zodiac – setup entailed clamping the echosounder and rod to the wood, mounting the RTK receiver to the rod, and connecting the cable to the controller. Collection took me all of 15 minutes to get comfortable with…“…people will come to love their oppression, to adore the technologies that undo their capacities to think.” -Neil Postman
- MemberAugust 12, 2019 at 3:09 pm
I heard they had a lot of problems with the dual frequency Sonarmites but that they now have them ironed out. Back when I was in sales I sold quite a few of the single frequency ones and never got any negative feedback.
With a Trimble data collector you can Bluetooth to the Sonarmite, set the collector to automatic topo, and just drive the boat collecting at whatever time or distance interval you choose. When finished you can export files containing the depth and bottom elevation.
Even though I was at a Trimble dealer at the time, we also sold one to a Leica user and I was able to get it set up for him to work in a similar manner.
- MemberAugust 13, 2019 at 5:47 pm
Not sure if the USACE has a large presence in your area or not but we have the St. Louis district office here along with some others like KC, Rock Island, Memphis that border the district. Several companies around here have their hands on COE contracts. A former employer of mine was one of them. They had several boats that ranged from a little 10′ dingy to a 26′ Sea Ark that cost $250k to buy and setup. We’d run the up and down the Mississippi and Illinois Rivers doing channel surveys or Pre/Post dredge surveys. We’d do scour surveys on the downstream sides of the lock and dams also. We’d used a smaller john boat to do scour surveys below dams of COE lakes in the district also. A couple of the lakes have pretty small outfalls so we’d just put on the waders and do x-sections. I know that they’ve gotten away from giving out contracts to large firms in recent years. The company I did work for was very large and they ended up selling off their St. Louis office survey division to a small company and that company now does it all.
- MemberAugust 14, 2019 at 5:30 pm
Have you looked into the hydrone and sonarmite? We used one earlier in the summer for 5 ponds at a former gravel pit. Attach the gps/data collector and send it on its way. The largest pond was 150m X 350m and no issue with controlling the remote control boat except when its far away to determine which way the boat was facing
Log in to reply.