An improved approach to estimating the infiltration characteristics in surface irrigation systems

Abstract

The most common methods for estimating the infiltration function are measurements through a double-ring infiltrometer (DRI) and empirical models. Infiltration data always exhibit different kinds of scatter, which affect the accuracy of the estimated infiltration function. This study presents a new methodology to calibrate the infiltration function. The suggested approach is based on combining the DRI method with the changes in the measured soil water content. Furrow irrigation experiments were conducted to estimate the infiltration function using different methods and to investigate the effect of data scatter on the reliability of the estimated infiltration function. Furrow elevations were observed, and for each irrigation event advance times, recession times, and inflow rates were observed. The infiltration depths were measured as a function of the change in the soil water content before and after irrigation event. Infiltration parameters were estimated using DRI treatment, empirical model (Kostiakov model), and suggested approach. Measured and simulated infiltration depths using the described methods were compared. The results show that the infiltration depths estimated using a DRI were lower than the observed infiltration depths, while the infiltration depths estimated using the empirical model were higher than the observed infiltration depths. The results indicate that the infiltration function estimated using the recommended approach was more accurate and reasonable than the infiltration function estimated using the DRI, and empirical (Kostiakov model) methods. In addition, the proposed approach can reduce the required measurements during the irrigation event, and can also reduce the potential scatter in the estimated infiltration function that results from soil variability and measurement errors.

Improvement of the estimation of the infiltration function in surface irrigation systems

“…The soil infiltration process can be described by the Kostiakov model Eq (9), and the infiltration time at each point in the border field satisfies Eq (20). Hence, the distribution formula of…”

“…The infiltration function can be estimated based on the advance time, recession time, and infiltration time. Water advance time is the relationship between time and distance in waterfront advance, and the water recession time is the relationship between time and distance that begins when the depth of surface water upstream decreases to zero and continues until the surface is drained [7][8][9][10][11]. The infiltration time is the duration it takes for the water to reach a certain depth in the soil.…”

“…In both methods, the accuracy of the infiltration time depends on the accuracy of the estimated advance and recession times and therefore on the measurement of the advance and recession times. Measuring advanced times is easier than measuring recession times, especially in a large-scale project where collecting data requires more field researchers [9]. As a result, the estimated advanced time is more accurate than the estimated recession time.…”

Evaluation of Furrow Irrigation Efficiency: A Case of Omo Kuraz - III Sugar Factory Irrigation Farm, SNNPR,Ethiopia

“…It is difficult to determine the cause of these advance and recession time variations specifically since it depends on different factors. The possible reasons are decrease in inflow rate along the furrow (for advance time), the slope variations at some parts of the furrows, measurement errors, and very large variations in soil texture in the fields [23] (Figure 5). As observed from the graph it is increasing trend from point of inlet to the outlet at the end of furrow (Figure 6).…”