Monitoring of Water Table Fluctuations in Kano River Irrigation Scheme, Nigeria

Abstract

The effect of seepage from canals and a non-functional drainage system has caused the water table to rise near the surface in many areas. The water table at shallow depths leads to the depletion of oxygen in the root zone and increases the risk of soluble salts and sodium near the soil surface. To address this issue in the Kano River Irrigation Scheme (KRIS), water table depth was monitored for two years using a Laser Distance Meter (40 m) from 85 wells drilled in the Scheme. Descriptive statistics and tests were carried out on the data collected. The study revealed that water table fluctuations were influenced by the rainfall observed during the rainy season and even though the water level raised to about 1 m to the ground surface, no part of the scheme had observed a water table to the surface.  The shallowest water table depth of 0.7 was recorded in September 2020 and 2021.  The t-test has shown that the water table depth for the rainy seasons of the two years is not significantly different. However, there is a high potential for salt accumulation as the capillary groundwater approaches the surface due to the likelihood of salt influx within the root zone.