Systems approach in assessing suitability of groundwater for irrigation in western region of Saudi Arabia

Abstract EN

One of the empirical parameters, most commonly used in assessing the quality of irrigation water is the sodium adsorption ratio (SAR).

The other parameters are total dissolved solids (TDS), total ions (Ca' Mg1 ', Na + , K\ HCOj, CO, .

S04CL“, ...etc.) and trace metals.

In order to minimize soil and crop problems, especially in arid areas due to high evaporation rates and subsequent salt build up, the SAR ratio must be close to the acceptable limits.

In order to determine SAR values extensive water quality sampling analysis efforts, which are time and labor intensive, arc needed.

Groundwater quality data for 190 locations (wells) in the Western Region, Saudi Arabia, was collected.

Out of this data, 138 points were used in developing regression models between TDS and: (l)SAR; (2) Total ions; (3) MajorcationsandStrontium (Sr) metal (mostcommonly found in the Western Region geological formations).

The developed regression models have goodness of fit (R-)- ranging from 0.7 to 0,99 indicating a good relationship.

The six data points were used to check the validity of regression models.

The developed models offer convenient and easy approach in estimating SAR.

Total ions and Sr, provided TDS value is know n Measurement of TDS is relatively easy.

The calculated or estimated values of SAR help in the assessment of groundwater suitability for irrigation purpose.