Determination of Groundwater Potentials in Crystalline Basement Areas of Bauchi Local Government Area, Bauchi

Abstract

Developing groundwater is generally an excellent option for sustainable water supplies in Bauchi due to the ephemeral nature of surface water. However, the large variability in geological and hydrological conditions have a profound influence on the availability of groundwater across the study area. The rationale for this research is to contribute at least, in terms of providing empirical data towards sustainable development of groundwater resource, particularly in the Crystalline Basement hydrogeological unit of Bauchi area. Aquifer properties of wells within the Crystalline Basement were estimated from a constant-rate pumping test of 10 sampled wells by fitting mathematical models (type curves) to drawdown data through curve matching. Generally, yields of sampled boreholes within the crystalline basement aquifer range from 8.64 m 3 /d to 120.96 m 3 /d with an average of 52.36 m 3 /d. The total yield of the boreholes is about 661.83.m 3 /day. This can sustain a population of 26,473 based on water supply standard of 25 litres per day for rural communities (Babatola, 1997). Considering the total population of 12,218 people (NPC, 2014) that are currently using the water points in comparison to water supply standard of 25 litre per person per day, this shows that the aquifers from the 10 sampled boreholes have relatively enough groundwater in terms of yield to meet the water need of the population. However, any significant increase in population growth may result in water scarcity in these areas, as the Crystalline Basement aquifers generally have low yielding capacity. Also, the crystalline basement aquifer properties evaluated reveal that the transmissivity values range from 2.55 m 2 /day to 111.0 m 2 /day with an average of 38.94m 2 /day (Table 5). According to Offodile (2002), a transmissivity range of 5 to 50 m 2 /day could be regarded as high potential in crystalline rock situations. By the above standard, the crystalline basement aquifers in the area are classified as aquifers of negligible to high potentials. The specific capacities of boreholes in the study area were computed and the results show that they vary between 1.30 to 691.2 m 2 /d/m.