Spatial Variation of Hydraulic Conductivity Categories in a Highly Heterogeneous Aquifer: A Case Study in the North China Plain (NCP)

Compared with research on spatial variation of hydraulic conductivity (K), less effort has been made researching different grades of K value in the North China Plain (NCP). In this study, 3D spatial distribution models of different grades of K were established by considering the effects of clay fraction content and uniformity coefficient (C_u). The K value can be divided into five grades: very low, low, permeable, high, and very high groups. The volume percentages of these clusters were 3.06%, 36.01%, 55.70%, 4.82%, and 0.41% for the first aquifer; 0.016%, 9.56%, 88.25%, 2.16%, and 0.014% for the second aquifer; and 0.04%, 17.74%, 84.21%, 0.001%, and 0.01% for the third aquifer. It is concluded that the high and very high K values are fully affected by burial depth and that the very low, low, and permeable K values are mainly controlled by depositional environment and are partially influenced by burial depth. The burial depth became the main influencing factor only within the same depositional environment, causing the overall K to decrease with depth. The variations of very low, low, permeable, high, and very high categories of K values with depth are described in this study. This can provide useful information for non-technical decision makers to achieve sustainable development of deep groundwater resources.