Shallow groundwater condition for irrigation along dryland river basin, northwestern Nigeria

Abstract

This study investigated shallow groundwater quality and yield for irrigation along Hadejia River Basin of Jigawa State in both the dry and rainy seasons of one year. Sites in the floodplain with a history of irrigation where the use of tube wells is dominant were selected covering a transect of about 135 km. Six transects, oriented perpendicular to the river channel were established within 1 km2 in each site. Three tube wells were sampled and positioned along each transect at regular intervals, making a total of 18 wells in each site. To ensure quality control and quality assurance, the sampling standard methods prescribed by APHA (2005) were followed carefully for the collection of groundwater samples. Pumping test, which was repeated four times at 15 min interval in both morning and evening hours was used to measure groundwater yield. Multivariate statistical tools such as analysis of variance, Pearson product moment correlation, and cluster analysis were used respectively, to test the research hypothesis and to classify sampling points into similar groups based on groundwater quality. Results showed that the suitability of the water is lower in the dry season than in the rainy season. Average yield of wells for evening hours recorded a higher yield of 3.3 l/s (56%) than yield in the morning hours of 2.6 l/s (44%). Although groundwater average yield was found to be within the standard (2.5 l/s) for irrigation, it is realized that any extraction of the resource more than the prevailing rate can induce a decline in groundwater yield. A decision support system is recommended among the strategies to improve groundwater resources management in the area.