Shallow Wells’ Water Sustainability Appraisal at Ikere-Ekiti, Southwestern Nigeria

Анотація

This study examines sanitary situations and the volumes of water in shallow wells at Ikere-Ekiti, Southwestern Nigeria during the dry season of 2023 with a view to observe the hygienic levels of the wells, categorize the area into different groundwater potential zones and discuss alternative means for groundwater sustainability of areas with poor groundwater potential. In-situ hygiene characteristics of 30 randomly selected wells in the area were examined to provide preliminary qualitative quality status of the wells’ water for potability and human health sustainability. Subsequently, in-situ parameters (Temp. (?C), pH, EC (µS/cm) and TDS (mg/L)) of water from the wells were measured based on rock units with 5,15 and 10 wells from migmatite, granites and charnockites respectively using a portable multi-parameter pH meter. The wells’ coordinates were measured using Garmin GPS MAP 64sx. The water level and depth of each well were measured using a dip meter while their diameters were taken employing a tape meter. The volume of water in each well was estimated employing the formula, V= ?r?h, where ? is 3.14, r is the radius (m) and h is the depth (m) of the wells. The estimated volumes of water were categorized and employed in producing the groundwater potential map of the study area using Surfer 8. In-situ hygiene characteristics revealed that most of the wells fell short of the basic hygiene requirements for wells’ water rendering their water non potable and inalienable to human health sustainability. Measured in-situ parameters revealed that elevation (m) ranged from 365 - 391, 358 - 387 and 305 - 385 on migmatite gneiss, granite and charnockite respectively. Following the same order, temperature (^°C) ranged from 26.8 - 29.1, 27.0 - 30.2 and 27.0 - 29.9, pH from 4.37 - 6.55, 4.66 - 6.92 and 4.22 - 6.9, EC (µS/cm) from 306 -389, 306 - 426 and 283 - 459 and TDS (mg/l) from 50 - 270, 71 - 294 and 38 - 286 respectively. The water level (m) ranged from 2.37 - 6.90, 0.84 - 11.3 and 0.77 - 5.59 while the depth of the wells (m) ranged from 5.30 - 12.2, 3.40 - 15.00 and 1.70 - 6.83 on migmatite gneiss, granite and charnockite respectively. The estimated volume of water (m³) obtained following the same order of rock units ranged from 4.27 – 19.84 (av. 9.41), 2.82 – 45.49 (av. 4.53) and 1.52 - 9.09 (av. 9.62) respectively. Groundwater potential evaluation revealed that the wells located on migmatite gneiss fell in the fair - very good potential zones, while all of the wells located on charnockitic terrain were in the very poor - poor groundwater potential zones. Water from granites cut across all the zones. This study clearly revealed that groundwater sustainability in the study area is far from being achieved. Wells’ water hygiene was very poor while volume of water in the wells was low and cannot meet the water demands for human consumption and other domestic activities. Recipe can be sourced from the artesian wells in the area or through rain harvesting during the rainy season.