Comparison of accuracy and completeness of data obtained from three types of automatic water-quality monitors
Dataset Identification:
Resource Abstract:
A comparison of data (specific conductance, dissolved-oxygen concentration, temperature, and pH) collected by the U.S. Geological
Survey flowthrough monitor, the U.S. Geological Survey minimonitor, and a self-contained commercial 'packaged-sensor' system
indicates that the data obtained by means of the most complete of the three systems. The U.S. Geological Survey flowthrough
monitor is powered by 120-volt alternating current and in a heated weather-proof shelter. A pumping system brings water from
the stream to sensors clustered in a sample clustered in a sample chamber located in the shelter. This instrument measures
output from the senors; data are recorded in binary-coded decimal form on a 16-channel punched-paper tape recorder tape recorder
housed in the shelter. The U.S. Geological Survey's minimonitor is powered by an external battery and is housed in a weatherproof
shelter. This instrument measures output of instream sensors with extension cables having underwater connectors; data are
recorded in binary-coded decimal form on a 16-channel punched-paper tape recorder housed in the shelter. The packaged-sensor
system also measures output of senors housed in a packages that is submerged in the stream. It has internal power supply,
no moving parts, and does not requires a weatherproof shelter; data are stored are stored in solid-state memory. Minimonitors
were installed at four sites in Ohio where U.S. Geological survey flowthrough were in operation. Two package-sensor systems
also were assigned to each site and were alternated every two weeks. Detailed records were kept of (1) field measurements,
for comparison with monitor-system data from each instrument, and (2) equipment problems that resulted in loss of data. Results
of the comparisons shows that the flow-through monitor gave the most accurate and the most complete data.
Citation
Title Comparison of accuracy and completeness of data obtained from three types of automatic water-quality monitors