Accepted Papers - 3.pdf - UNESCO

National Seminar on Rainwater Harvesting and Water Management 11-12 Nov. 2006, Nagpur
65. An Overview of Electronic Probes for Water-Level Measurements
and Recording for Agricultural and Environmental Studies
Preamble
Hydrologic soil examination, such as
determination of the groundwater level, direction
of the current of groundwater, porosity of soils, for
agricultural and environmental studies needs waterlevel
measurements. While various devices are
available for measuring and recording water-levels
in open waters, water wells, tanks, boreholes, etc.,
recent probes [ 1, 2 ] based on electronically
measuring and registering water-levels with data
logging facility are the state-of-the-art devices. Such
probes are based on pressure measurements. By
attaching additional sensors, these probes also
measure and record temperature and electrical
conductivity of water. An overview of commercially
available water-level probes and some of their
properties are presented.
Water-Level Measurements by Sounding Probes
Sounding probes are provided with a measuring
tape with graduation in centimeters. The probe is
*Prof. ( Mrs.) Vijaya Agarwal
ABSTRACT
State-of-the-art electronic probes for water-level measurements and recording are
presented. By providing additional sensors, the probes can measure temperature and
conductivity of water besides the levels. The readings can be data logged. The probes are
self-contained with built-in battery, sensors and data logger encased in a hermetically
sealed casing. The data logging function is software programmed and the readings are
downloadable to a computer. Very low battery drain gives the battery life of 8 to10 years.
Commercial availability of the probes facilitates their easy adoption for agricultural and
environmental studies.
Key words : Water level measurements and recording, sounding probes, electronic probes,
data logging.
lowered in a well or a borehole. When the probe
touches the water, an audible or light signal is
produced. If the cable it lifted a little, the signal
disappears. At this point the depth can be directly
read from the measuring tape. Accuracy is of the
order of +/- 0.5 cm and depends on the quality of
the tape used.. The probes are available with
measuring tape in several lengths mounted on a reel.
Such probes are manually operated and normally
non-recoding type. A few water-level sounding
probes are depicted in Fig. 1.
Electronic Probes
Developments in microelectronics have lead
to commercial availability of probes with advanced
features. Electronic probes’ working is based on
pressure measurement with the help of a precision
pressure sensor. The pressure sensor is provided with
dynamic compensation for ambient temperature and
barometric pressure changes. Additional features,
measurements of water conductivity and
temperature, and data logging function can be
*Selection Grade Assistant Professor ( Electrical Engineering ), Department of Agricultural Structures and
Environmental Engineering, College of Agricultural Engineering, Jawaharlal Nehru Agricultural University
Krishi Nagar, Adhartal P.O., Jabalpur 482 004 E-mail : vijaya.agarwal @ gmail.com Ph. : 0761 – 2681820
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