Saltwater intrusion, erosion, and periodic flooding during severe storms are some of the critical problems bedeviling the precarious coastal environment of Nigeria. A time-lapse study aimed at monitoring the dynamics of saltwater intrusion within the coastland surrounding Ibeno, southeastern Nigeria is presented. Three (3) vertical electrical soundings (VES) and four time-lapse electrical resistivity tomography (ERT) profiles with minimum and maximum electrode spacing of 5 m and 40 m and profile lengths of 120 m and 150 m respectively were acquired in 2016 and 2017 using the Wenner and Schlumberger arrays. Data acquired from the field surveys were modeled with WINRESIST and RES2DINV software to generate 1D and 2D resistivity images of the subsurface. The VES results with a maximum survey length of AB = 300 m revealed a four-layer KH curve. The 2D geo-electrical sections delineated contrast between the high resistivity values obtained for the saturated freshwater zones and the low resistivity values obtained for the saturated saltwater zone. Expectedly, the intrusion was dominant nearer the coastline than inland. The salinity changes are believed to have been caused by both incremental tides passing through highly porous materials in the active-salinity change area and over-pumping of groundwater. The time-lapse resistivity measurements showed significant, active lateral salinity changes rapidly intruding the freshwater aquifers. The study demonstrates the application of time-lapse 2D ERT and vertical electrical sounding in identifying the spatial and temporal changes of saltwater intrusion in the coastal aquifer.

严重暴风雨中的盐水入侵，侵蚀和周期性洪水是困扰尼日利亚不稳定的沿海环境的一些关键问题。提出了一个延时研究，旨在监测尼日利亚东南部伊贝诺周围沿海地区咸水入侵的动态。在2016年和2017年分别获得了三（3）个垂直电测深（VES）和四个延时电阻层析成像（ERT）剖面图，最小和最大电极间距分别为5 m和40 m，以及剖面长度分别为120 m和150 m使用Wenner和Schlumberger阵列。使用WINRESIST和RES2DINV软件对从野外调查获得的数据进行建模，以生成地下的一维和二维电阻率图像。最大测量长度为AB = 300 m的VES结果显示出四层KH曲线。二维地电部分描绘了在饱和淡水区域获得的高电阻率值与在饱和盐水区域获得的低电阻率值之间的对比。可以预料，在海岸线附近的入侵要比内陆的入侵为主。盐度变化被认为是由于潮汐穿过活跃盐度变化区域中高度多孔的材料以及地下水的过度抽取造成的。随时间推移的电阻率测量结果表明，活跃的横向盐度变化迅速侵入了淡水含水层。该研究证明了时移2D ERT和垂直电测深在识别沿海含水层中盐水入侵的时空变化中的应用。