Institute for Rural Engineering, NARO

Development of a low-cost, labor-saving method to estimate water leakage in Agricultural pipelines

-Precise estimation with valve operation and pressure measurement-

NARO in collaboration with research group of Graduate School of Agricultural and Life Sciences, The University of Tokyo have developed a method to estimate the water leakage point and amount of leakage in agricultural pipelines by means of simple valve operation and pressure measurement. In the model experiment, we were able to estimate the leakage point and amount of leakage with high accuracy, with an error of approximately 1% and the maximum leakage rate of about 17%. This method does not require special equipment or large-scale operation such as draining water in the pipe and is characterized by low cost and labor-saving estimation. This method is expected to be helpful for periodic functional diagnosis of pipelines.

Overview

Many agricultural pipelines have been installed for more than 30 years, and hence there are many water leakage accidents reported due to aging of pipelines. Leakage in agricultural pipelines not only causes economic losses from water spills, but also there is a risk of inducing such as subsidence and slope collapse in the peripheral ground.

Periodic functional diagnosis of the pipeline is effective to prevent water leakage. The existing leakage detection methods developed for water supply etc. were excellent for pinpointing the location where the approximate leak location was known, but it is not suitable for periodic leakage surveys for the entire pipeline.

NARO in collaboration with research group of Graduate School of Agricultural and Life Sciences, The University of Tokyo have developed a method to accurately estimate the water leakage point and amount of leakage in agricultural pipelines by means of simple valve operation and pressure measurement alone. A special pressure wave is generated by operating the valve and the point and amount of water leakage are estimated from the change in water pressure in a measurement point. A pressure gauge installed in the pipeline is used for pressure measurement (if the pressure gauge is not installed already then, a new one can be installed easily on an air valve). This method is characterized by low cost and labor saving estimation as there is no need for special equipment or large-scale operation such as draining water in the pipe. This method can be applied to pipelines of any pipe diameter (size) and material, but it is easier to detect leakage in pipes with smaller pipe diameters and higher rigidity (harder to deform). It is expected to be useful for periodic functional diagnosis of pipelines.

Reference Information


Fig. 1 Outline of Experimental model pipeline and propogation of pressure waves.



Fig. 2 Pressure waveform (Experimental results)
(Amount of water leakage: 0.011(l/s),
Water leakage position:150m from downstream end valve

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