Extent and Distribution of Groundwater Resources in Parts of Anambra State, Southeastern, Nigeria

Abstract

ABSTRACT:The extent and distribution of groundwater resources in parts of Anambra State, Nigeria has been investigated. The results show that the study area is directly underlain by four different geological formations including, Alluvial Plain Sands, Ogwashi-Asaba Formation, Ameki/Nanka Sands and Imo Shale, with varying water storage and yielding capacities. Borehole depths within the Alluvial Plain Sands are shallow (5-30m) yet the sands are excellent aquifers with high yields (3-5 litres/sec) especially along the Anambra West -OnitshaOgbaru L.G.A. axis. Elsewhere the yield is low (about 0.5litres/sec) and may dry up at peak dry season periods. The Ogwashi-Asaba Formation occurs in a north-southerly trend and underlies Ekwusigo, Nnewi North and South and Ihiala Local Government Areas. This formation consists of multiple aquifers and a depth to water table ranging from 50 to 110m. Within it, transmissivity values of 37.54 to 95.5m 2

Analysis of heavy metals’ contamination in soils and water at automobile junk markets in Obosi and Nnewi, Anambra State, Southeastern Nigeria

“…3 The geologic map of Anambra State showing the study areas (after Nfor et al 2007) which agrees with (Nwachukwu et al 2013). The minimum values of concentrations for each heavy metal comes from the background (control) point except for Cr and Pb at point NN 02 and NN 03, respectively, which has lesser values of concentration than the background at the Nnewi auto junk market.…”

“…Ogwashi-Asaba is Oligocene-Miocene in age while the Ameki and Nanka Formations were deposited during the middle Eocene of the tertiary period. The Ogwashi-Asaba consists of a top layer of black to brownish humus and laterite, underlain by horizons of sands, clays, gravels, and cobbles with intercalations of brown to black lignitic coal (Nfor et al 2007). The Ameki Formation and Nanka Sands have thickness ranging from 50 to 300 m. Erosion and gullying are major threats to the environment.…”

Chemometric analysis for pollution source identification and human health risk assessment of water resources in Ojoto Province, southeast Nigeria

“…According to them, the first is an alluvial terrace deposit which is shallow (at about the range of 30-80 m) and most preferred by borehole drillers, while the second is encountered at greater depths (about 110-180 m) and is composed of iron-rich water (Akpoborie et al 2011). However, Nfor et al (2007) reported that three aquifer units characterize the Ogwashi Formation: first unit Commerce, agriculture, and industry are the main land use activities in the study area. Commerce activities include the buying and selling of auto spare parts, plumbing materials, plastics, agricultural products, and basic commodities for homes.…”

“…Previous researches reported that the Ogwashi and Nanka formations are prolific aquiferous geologic units with varying aquifer depths (Nfor et al 2007;Okoro et al 2010a, b;Akpoborie et al 2011). Studies by Okoro et al (2010a, b) reported various aquifer properties, including hydraulic conductivity, transmissivity, and pumping test estimates, of the Nanka Formation.…”

“…Studies by Okoro et al (2010a, b) reported various aquifer properties, including hydraulic conductivity, transmissivity, and pumping test estimates, of the Nanka Formation. According to Nfor et al (2007), the Nanka Formation generally has its aquiferous layers at depths ≥ 20 m, whereas Okoro et al (2010b) reported that the aquiferous layers are at depths of ≥ 7 m. However, Akpoborie et al (2011) delineated two major aquifer systems in the Ogwashi Formation. According to them, the first is an alluvial terrace deposit which is shallow (at about the range of 30-80 m) and most preferred by borehole drillers, while the second is encountered at greater depths (about 110-180 m) and is composed of iron-rich water (Akpoborie et al 2011).…”