Indirect estimation of deep percolation using soil water balance equation and NASA Land Simulation Model (LIS) for more sustainable water management

Abstract

Sustainable management to water resources involves precise estimation for groundwater recharge. The better understanding of the estimated amount of deep percolation and behavior would contribute to more sustainable water resources planning. Soil water balance (SWB) equation computes deep percolation (DP) precisely if adequately applied. Lysimeters are efficient instruments used to compute each component of SWB model with high accuracy. This method is very sophisticated and costs A CCURATE estimation for groundwater recharge is required for more sustainable management to water resources. On-farm level, deep percolation is one of the water loss sources that researchers and agronomists work hard to minimize. However, on a large scale or district level, it is considered as a valuable source for recharging the aquifer. Indirect estimation to deep percolation would be an economic effective mean, especially for large scale studies. The presented research study aims at checking the capability of Land Information System (LIS) model in estimating deep percolation by soil-water balance equation. The model was validated using precipitation data extracted from meteorological stations randomly selected and distributed along the Nile basin. Multi-thematic map layers including all soil water balance model parameters, i.e. deep percolation and change in soil moisture content were developed to the year 2013 at a scale of 10 km 2. The relationship between measured rainfall values and estimated ones by LIS has a coefficient of determination (R 2) of 0.88. The obtained results revealed a good capacity of LIS model in estimating deep percolation on large scale from its direct simulation to the soil-water balance parameters. It was found that deep percolation rates were generally higher in the Nile River's downstream than in upstream especially in Egypt, Sudan, and parts of Uganda. This is in contrary to the behavior of precipitation rates and both surface and sub-surface runoff. They were higher in upstream countries than in downstream ones. The highest deep percolation rate (19.63 mm day-1) was observed in Ethiopia and parts of Sudan during May 2013. It was found that low elevated lands with loose texture tend to have higher rates of deep percolation than elevated rocky lands. The current research results could be of great benefit for sustainable water management in Egypt. However, further study should be conducted in different agro-ecological zones in Egypt for more precise model calibration and validation. This may require access to large amount of field data and long-term meteorological data to run the model.

Detecting and Mapping Salt-Affected Soil with Arid Integrated Indices in Feature Space Using Multi-Temporal Landsat Imagery

“…It is characterized by imperfect to well-drained soil as it was formed within the alluvium of the Nile delta, which has been deposited in semiarid climates [66]. The hydrology of the area is affected by both the River Nile irrigation canals, and the seepage from the Mediterranean Seawater, but overall, the groundwater quality of the area is mostly good [66][67][68]. The natural environments in the region can be classified into three main types: agricultural and urban environments, coastal environments, and wetlands.…”

Modelling Projected Changes in Soil Water Budget in Coastal Kenya under Different Long-Term Climate Change Scenarios

“…These results are similar to those in some studies. Elbana et al (2019) [90], who concluded that higher rates of deep percolation could be found in the loose soil with low slope. Omulabi et al (2000) [65] studied the influence of soil physical properties on infiltrations rates of sand, clay and silt concluded that infiltration rates varied significantly between the three.…”

A modified equation for fitting the shape feature of the entire soil water characteristic curves

“…Such task was not adopted because our objectives were the full curve determination and a comparison of the equations based on similar conditions. Therefore, the models required special measurements of soil properties, and the models with technical disadvantages were considered out of the comparison (El-Nady, 2015 andElbana et al, 2019).…”

“…2-6 and appendix A). In this respect, Elbana et al (2019) suggested conducting further studies in different agro-ecological areas in Egypt to optain more precise model calibration and validation. The PE was tested based on actual measurements of the SWCC between 0 and 1500 kPa suction for a clay soil (Fig.…”