SR-23 : Infiltration measurement techniques / equipment

Abstract

In water management and conservation studies,' accurate information on the rate at which different soils will take in water under different field conditions is required. The rate of water entry into soils varies widely between different soil types and also within a single soil type, depending upon soil water content and management practices. Infiltration is defined as the movement of water from the atmosphere to the soil across some definable but intangible interface. It is reported in units of depth per hour. The infiltration might best be regarded as a concept because one cannot see or directly measure it without influencing its value. However, it may be approximated by a variety of different methods. Quantification of infiltration and infiltration capacities has been the subject of a large number of studies, with most of the successful measurements being made on disturbed, non-forested lands, especially crop and rangelands.

Measuring infiltration and infiltration capacities is difficult, since both are influenced by the rate of application and several other factors associated with the phases through which the infiltrating water passes. Hydrologists, soil scientists and irrigation engineers have developed several equipment and techniques for the determination of the infiltration rate of a soil.

The National Institute of Hydrology, Roorkee has taken up developemnt of an electronic infiltrometer for efficient as well as reliable measurement of infiltration rate in field. In order to ascertain the state-of-art of infiltration measuring equipment and techniques, an exhaustive literature survey was conducted for this purpose. The present report summarises the literature survey, and has been prepared by Sri V C Goyal and Sri B P Roy, Scientists of the Institute.