Goodbye Pygmy Meters, Hello Flo-Mate at Lavaca-Navidad River Authority

The Lavaca-Navidad River Authority (LNRA) is a state conservation and reclamation district that was established in 1959. Located in southwestern Texas, 100 miles west of Houston, it was originally known as the Jackson County Flood Control District until 1969. Its mission is to control, store, preserve and distribute storm and flood waters of Jackson County as well as the waters of the county including rivers, streams and tributaries.

The river authority was also the local sponsor of the United States Bureau of Reclamation's Palmetto Bend Dam and Reservoir project on the Navidad River, which built Lake Texana. In 1972 the authority obtained a water-rights permit for 75,000 acre-feet of water a year from Lake Texana. Since the early 1980s the river authority has operated and maintained Lake Texana and its recreational facilities and 7,000 acres of surrounding land. The authority also works with other entities, including cities and counties, to plan and coordinate various operations, including public events, law enforcement, disposal of wastewater, plans for floods and emergencies, and maintenance and construction of drainage systems. Additionally, the LNRA is one of fifteen partner agencies along with the Texas Commission on Environmental Quality (TCEQ) involved in the Texas Clean Rivers Program (CRP). The CRP is a state funded water quality monitoring, assessment, and public outreach program. The CRP provides the opportunity to approach water quality issues within a watershed or river basin at the local and regional level through coordinated efforts among diverse organizations.

According to Sylvia Balentine, Director - Environmental Section for the LNRA, “We needed to monitor flows and the TCEQ recommended the Marsh-McBirney Flo-Mate Flow Meter. Because the data is turned over to the TCEQ we wanted to use a meter that they accepted.” Balentine had used troublesome Pygmy style flow meters in the past but once they realized that the commission preferred the data to be from a Marsh-McBirney meter, she adds, “We said good-bye to the Pygmy meters forever. With the Pygmy meters there are just too many things that can go bad with them.”

Concerning the accuracy of the data from Pygmy meters, she comments, “I don’t always trust the data from the Pygmy meters. Unless you spend a lot of time calibrating those meters the data from them is suspect. You have to be highly skilled to use the Pygmy meters accurately but with a lot less skill you can get good readings from the Marsh-McBirney Flo-Mate. The meters are a lot more hardy than trying to carry those fragile Pygmy meters around with the little cat hair whiskers on it. If you hit a bump you can easily mess it up.”

The mechanical style Pygmy meter utilizes cat-whisker contact chambers with magnetic heads that are subject to possible multiple-count errors at low velocities. The proper adjustment of the cat whisker on the meter is critical, especially at low velocities. When taking flow measurements under rugged field conditions, the probability of errors on the Pygmy meter is great. Balentine comments, 'The Lavaca Basin tends to either have flooding or low flow conditions. There is rarely anything in between. Also, we are dealing with flood fed rivers not spring fed rivers. The Flo-Mate’s ability to monitor during low flow conditions was another reason for choosing the meter.”


Unlike the Pygmy meters, the Flo-Mate Portable Flow Meter is a rugged field meter with no moving parts. The lightweight and water resistant electronics make it an ideal field meter. The hands-free neck strap of the meters electronics fits comfortably around the user’s neck. Accurate flow measurements are taken by the electromagnetic sensor which can be easily mounted on a standard wading rod. The proven electromagnetic sensor introduced in 1974, assures the user of unsurpassed accuracy and dependability without the need for field adjustment. When the sensor is placed in flowing water, its magnetic field generates a voltage that is sensed by the electrodes and transmitted through the cable to the meter. The flow rate is instantaneously displayed on the instrument panel. Data storage and recall of up to 19 data points, adjustable filter modes and battery saver mode are just a few of the features designed into the meter to simplify the flow measurement process. The Flo-Mate has earned an outstanding worldwide reputation for its accuracy and ease of use and is recommended by governmental agencies as a replacement for old-style mechanical type meters.

Balentine and her co-worker Chad Kinsfather use the Flo-Mate in a multitude of applications including flow monitoring at their water quality sites where there are no USGS gauges, wastewater treatment plant permit renewal for surrounding communities, reservoir monitoring and the calibration of gauges at their USGS sites to ensure the meters are capturing accurate flow data. Balentine adds, “Since we are so busy using the meter for water quality purposes, we needed to purchase another meter for the employees on the water quantity side of the authority.” As the LNRA completes another successful flow monitoring project and they head out to the field for their next one, they can rest assured that the Flo-Mate will continue to provide accurate flow data for many years to come!