Importance of Hydrologic Field Work Often Overlooked

Sol Resnick, former director and now director emeritus of the Water Resources Research Center, contributed this Guest View.

I am a hydrologist who happens to enjoy field work. But in my working lifetime I have seen a great difference in the way hydrologic problems are solved. In the 1960s and 1970s, it became fashionable to adopt a mathematical or statistical approach, for use with computers, and to develop hydrologic models.
I am the last person in the world to knock the work that is being done. It is important. But hydrologic field work is just as important, and this is what most people do not want to do anymore, although federal agencies are still doing good field work, for example, near Tombstone. At the university when the Water Resources Research Center had a cutback, the field lab was the first to go.

Resnick doing field work for the TVA, Aug. 1942, at Claypole Weir in Thompson Creek area in Virginia.

In the early 1940s, I worked with the Tennessee Valley Authority (TVA), with such world-class hydrologists as Ray Lindsley and Bill Ackerman. These early hydrologists were field oriented. They worked on designing, building, and installing weirs to measure storm runoff as well as equipment to measure amounts of eroded sediment and networks of rain gauges.

When I was at Colorado A&M in the late 1940s, I worked with Ralph Parshall and Carl Rohwer. They had retired from the U.S. Agricultural Extension Service and were now developing low-cost farm irrigation equipment. Parshall developed a flume for measuring flow onto irrigated fields that is still used all over the world. He wrote up the design and flow data tables which were provided through the Extension Service. He did not patent it, although it could have made him very rich. This is unlike today when universities and their scientists patent almost everything they develop.

I also taught hydrology at Fort Collins in the 1940s, and my course outline at that time was completely different than what is used today. There was a much different approach back then. When I was teaching, hydrology included field work, and I made field work 25 percent of the final grade.

Later, when I was teaching at the University of Arizona, this caused a problem. I had an Egyptian student who came from a good family. During the first day of class I had told the students that 25 percent of their grade will be made up of field work, with one afternoon a week out in the field. When the class turned in its reports I did not get one from him, and I called him in to ask what happened.

He said in Egypt he did not go out in the field because he had workers go out in the field. He tells them what he wants, and they get it for him. I asked him how he knows what he wants, explaining that each situation is unique, and field work is a way to get the best idea of different situations.

I gave the student a C, although I could have given him a D. UA President Harvill called me in his office and told me that the Egyptian Embassy had phoned him about the student’s grade. I told President Harvill about the importance of field work, and he backed me up.

When I went to India they did not have the money that TVA had, to buy such equipment as recording rain gauges, water recorders, and equipment for measurement of eroded sediment. I had to collect data in other ways, less accurate but much less expensive. For example to obtain river flow records, I painted foot marks from zero at the river bed to the bottom of the bridge on one of the pillars of a bridge. As you crossed the bridge you could quickly see what the reading was and make a note of it. Over time you had readings of the height of the river at the bridge and could change that information into flow records, (Q in cubic feet per second) with the use of a rating curve.

Since Q = Area of flow (ht x width, ft2) x Velocity of flow, ft/sec, using a bridge where the width of flow is a constant, the rating curve can be easily developed by noting the velocity of flow at a low, medium, and high flow. The velocity can be measured near the bridge by timing a float over a measured distance.
Cheap methods for gathering data were needed. Although these may not be as accurate as other devices, they were better than nothing. I tried to work in this message whenever I lectured in places like China.
I recently got a message from a consultant in India who said for some reason the groundwater in his area was getting saltier and more polluted, and he did not know why. The area is right on the coast, and he did not know it was due to sea water intrusion. He never tested the waters, the seawater or the polluted groundwater. How do you come up with an answer if you do not know what the cause of the problem is? But this is what you pick up by doing a little testing, a little field work.

The new sophisticated modeling methods are good for big areas. If you have the right data, you can come up with some very good models, and it takes a country like this one to develop the models. There may be comparable areas in countries like India and Africa where these models can be used, although every situation is different; hence you have to put some real data in those programs. Unfortunately, it is easier to sit before a computer than go out and fight the heat and the rain to collect data.

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