That’s usually the question we get asked when out on a river performing a hydrographic survey (“hydro survey”)! “Are you guys fishing?” This is especially the case when on a smaller stream such as the Truckee River or the Colorado River near Yuma. “Hydro what?” Most folks doing hydro surveys are on the coasts, in the northwest or the northeast, on big water, and what they do normally entails using boats like this…
If you’re not on the coasts, then this is the typical picture of “hydro survey:”
But what we have specialized in and will be discussing is something a little more in-between. There are many streams that are too deep to be waded but too small for large boats. We call them “shallow western streams.” For these shallow western streams, you might need jet boats like this:
You also might need more zanier watercraft to get in those truly “inaccessible” areas, where sand would clog up your jet boat or where there are no boat ramps:
In the mid ‘90s, our company was doing hydraulic modeling, bridge scour analysis, flood mapping, stream restoration, and even levee repair and habitat analysis, and we needed highly accurate bathymetry and underwater data. So what did we do? We simply developed the capability to do this in-house. In the past 15 years, our folks have been on streams as small as the Dolores River in southwestern Colorado to streams as large as the Sacramento River and from small ponds to reservoirs like Fort Peck Lake. In the coming weeks, we’ll discuss some of the basics of hydro survey on shallow streams: the boats, the equipment, processing the data, the problems and pitfalls, and even tackling the inaccessible areas.