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Title: Development and application of a thermistor current meter
Authors: Way, Carl M.
Burky, Albert J.
Miller-Way, Christine A.
Keywords: Streamflow
Stream measurements
Scientific apparatus and instruments
Stream ecology
Publisher: Environmental Laboratory (U.S.)
U.S. Army Engineer Waterways Experiment Station.
Series/Report no.: Technical Report ; EL-94-1
Abstract: This report provides details for the construction of a hot-bead thermistor current meter which is capable of measuring water velocities on a millimeter spatial scale and for the construction of a compact and accurate calibration system. Hot-bead thermistor current meters can be built with response times of 200 ms capable of measuring velocities between 0.1 and 80 cm s⁻¹ . The construction of a sturdy probe for application in lotic systems such as high gradient Hawaiian streams was achieved by the use of heavy-duty acrylic tubing, small stainless steel gas-chromatography tubing, and flexible Tygon spaghetti tubing. An acrylic handle anchors the electrical cable at one end and the thermistors at the other. The following criteria were central to the development of the calibration system: (a.) accurate calibration; (b.) compact unit for storage and use in limited laboratory space; (c.) leak-proof system; (d.) inexpensive design requirement for readily available materials; and (e.) construction requirements for the use of hand tools. The thermistor current meter has been used to measure velocities in the water column and around various substrate features in riverine habitats. More detailed spatial velocity measurements were made in streams by dividing a habitat into small grid cells. With fine spatial scales (e.g., grid sizes of 200 to 300 cm² or less) and repetitive sampling under varying water flow conditions,, insights into relationships between various spatial and temporal characteristics of microhabitat velocities were made. The current meter has been used to determine ambient velocity profiles around a variety of benthic stream organisms including gobiid fishes, atyid shrimp, neritid snails, larval chironomids, and larvae caddisflies. These data can provide insights into the distribution, abundance, feeding patterns, reproduction, and behavior of the organism. Additionally, these data can be used to determine the spatial and temporal relationships between benthic velocities encountered by an organism in its daily life and velocities elsewhere in the water column. The current meter/probe can provide much needed data on (a.) quantification of spatial variation in velocity regimes in both lotic and lentic habitats-these types of data can provide insights into the dynamics of water movement on a fine scale; (b.) temporal variation in velocities within a microhabitat; (c.) the effects of short- and long-term disturbance events on velocities in a microhabitat; (d.) quantification of the velocities encountered by an animal or plant through space and time; and (e.) an understanding of the relationship between gross macrohabitat velocities and velocities encountered on a microscale by an organism. These data can provide information on the distribution, abundance, ecology, and behavior of important Jotic and lentic organisms and provide the basis for decisions on the management of water flows in critical habitats.
Description: Technical Report
Gov't Doc #: Technical Report EL-94-1
Rights: Approved for Public Release; Distribution is Unlimited
Size: 41 pages/3.58 Mb
Appears in Collections:Technical Report

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