Evaluation of Lithological Effect on Aquifer Transmissivity and Conductivity in Parts of Rivers State, Nigeria using Vertical Electrical Sounding (VES)

Vertical Electrical Sounding (VES) was used to evaluate the effect of lithology on aquifer transmissivity and conductivity in parts of Rivers State, Nigeria. A total of 10 Vertical Electrical Sounding were conducted at ten locations. The VES data were collected using ABEM terrameter SAS 300B and processed using Win-Resist Software and Microsoft Excel Sheet. The effect of the lithology on aquifer transmissivity and conductivity were analyzed. Result from the Vertical Electrical Sounding revealed a four to six geoelectric layers. The aquifer resistivity values range from 39.40Ωm to 17290.7Ωm. Results of the aquifer conductivity values range from 0.005 to 2.538cm/s with the highest value dominating in the central part of the study area suggesting large grain sands that can permeate groundwater flow while the transmissivity values range from 0.22587cm/s2 to 132.487 cm/s2 with average of 19.1587cm/s2. Area with high transmissivity is identified with high groundwater potential permeable with groundwater flow is seen in the central part of the study area with range of 110 to 135 cm/s2 indicating a thick sandy aquifer. Result from the nearby borehole in correlation with the VES point showed an agreement with the VES data at Ogale Eleme and Elelenwo location. The result of the study can be applied in ground water resources management, hydrological studies and provides valuable information for town planner.

Quantifying groundwater fluxes from an aapa mire to riverside esker formation

Water flows in peatland margins is an under-researched topic. This study examines recharge from a peatland to an esker aquifer in an aapa mire complex of northern Finland. Our objective was to study how the aapa mire margin is hydrogeologically connected to the riverside aquifer and spatial and temporal variations in the recharge of peatland water to groundwater (GW). Following geophysical studies and monitoring of the saturated zone, a GW model (MODFLOW) was used in combination with stable isotopes to quantify GW flow volumes and directions. Peatland water recharge to the sandy aquifer indicated a strong connection at the peatland–aquifer boundary. Recharge volumes from peatland to esker were high and rather constant (873 m3 d−1) and dominated esker recharge at the study site. The peat water recharging the esker boundary was rich in dissolved organic carbon (DOC). Stable isotope studies on water (δ18O, δ2H, and d-excess) from GW wells verified the recharge of DOC-rich water from peatlands to mineral soil esker. Biogeochemical analysis revealed changes from DOC to dissolved inorganic carbon in the flow pathway from peatland margin to the river Kitinen. This study highlights the importance of careful investigation of aapa mire margin areas and their potential role in regional GW recharge patterns.

GEOLOGICAL AND GEOMORPHOLOGICAL ANALYSIS AND HYDROGEOCHEMICAL ENVIRONMENT OF AQUIFERS OF THE SOUTHERN WEST COAST OF KARNATAKA, INDIA

Dakshina kannada district is situated in peninsular region. The peninsula is composed of geologically ancient rocks of diverse original and most of them have undergone metamorphism. The early Precambrian tonalitic gneisses invaded by granites, granulites and dolerite dykes. Granulites are mostly restricted to areas south of Mangalore. High grade alumina rich (corundum bearing) metamorphic schists have been encountered and younger alkaline intrusive rocks like Aegerine syenites have been reported. There are ve rivers and estuaries. Number of lineaments cut across each other and some lineaments are parallel to each other. The Arabian sea class is the largest among other land cover features in the study area. The river/tidal creek land cover appear as long irregular and sinous in outline. Mulki river, Netravati river, Gurupur river at southern terrain. The qualities of groundwater at sandy aquifer are good, lateritic/weathered gneissic rocks it is sweet.