Hydrometry Introduction

I found this book at the NC State Library:

Hydrometry, 3rd edition: A comprehensive introduction to the measurement of flow in open channels
UNESCO-IHE Lecture Note Series
Wubbo Boiten, Wageningen University, Delft, The Netherlands

Here's the publisher's description.

Based on this book and other sources I may find along the way, I hope to post a few times about the basic measurements taken along streams and rivers.

Initially, water resource measurements can be broken into two categories; quantity and quality. On the quantity side, we want answers to questions such as: do we have enough to drink, is there a risk of flooding in a certain location, are impermeable surfaces such as parking lots creating too much increase in stream flows, etc. The quality side seems obvious because we all want clean drinking water, but there are also less obvious concerns such as sediment transport, nutrient levels, wildlife impacts, and so on.


First let's look at quantity measurement.
When news about a flood hits the airwaves, we're always given stats like flood stage and water height. So water height is necessarily of interest. How do we measure it?
In talking to Dr. Birgand and in reading this book, I find five basic measuring techiques for water height.
1.) Staff Gauge
2.) Float/Counterweight Systems
3.) Pressure Transducers
4.) Bubble Gauges
5.) Ultrasonic sensors

The image on the left is a USGS Stream Gauge Station near Pullen Park in Raleigh, NC. In the background, you can see a white "stick" in the water. That is a staff gauge, which looks a lot like a measuring stick.


In addition to height, we also like to know how much water is flowing in a stream or contained in a reservoir. In streams this is measured as volumetric discharge, in units such as cubic meters per second or gallons per minute. Here are some classic methods for calulating discharge:
1.) Velocity Area method
2.) Slope Area method
3.) Stage Discharge method
4.) Acoustic Methods
5.) Electromagnetic Methods

I've used the Velocity Area method for calculations in class. The remaining four methods I hope to learn more about.

There's plenty to read about quantity measurements, so I think I'll leave the discussion of quality for another time.

USGS National Water Quality Assessment

According to the USGS website, "The National Water-Quality Assessment Program (NAWQA) provides an understanding of water-quality conditions and how those conditions may vary locally, regionally, and nationally; whether conditions are getting better or worse over time; and how natural features and human activities affect those conditions."

There is a ton of information here about NAWQA, including some links to research about chemicals found in source water. USGS calls this program SWQA, for Source Water Quality Assessment. The source water program is interesting because they are looking at the water that's flowing IN the water treatment plants, as well as the water that is leaving the plants. So far they have found a lot of chemicals surviving the treatment process. However, they stress that many of the chemicals they are looking for are unregulated, and often found in very low doses that don't have known consequences to the end user. They also delve into the various ways the study could have been flawed (ex. how can you be sure you are testing the same water at both ends of the treatment plant?).

From my limited conversations with people who look at stream water quality and people who look at water treatment processes, it sounds like there isn't a lot of communication between the two groups. It would seem logical that the two groups would have a lot of information to share, or at least compare. This gets into one of my pet peeves, actually. We seem to exert a lot of energy chasing after answers that someone else has already caught. That said, I know how easy it is to be busy trying to be productive and not have the leisure time to go listen to someone else talk about what they've been up to. And, I suppose there are times when we want the same information, but in a different context.

Fire Water

Here's a crazy article Dr. Knappe (Civil Engineering) forwarded today!

Article & Link to Video:
Fire Water