Permeability and Groundwater Enrichment Characteristics of the Loess-Paleosol Sequence in the Southern Chinese Loess Plateau

Abstract

To determine the permeability characteristics and the groundwater enrichment conditions of loess and paleosol layers, this article systematically investigated the permeability, magnetic susceptibility, porosity, and carbonate mass percentage of representative loess-paleosol layers (L1 to S5) on the Bailu tableland in the Chinese Loess Plateau south. The result of in situ permeability measurements showed that the average time to reach quasi-steady infiltration of loess layers is shorter than that of paleosol layers. In addition, loess layers have higher porosity and better water storage spaces than paleosol layers and were prone to form aquifers. Paleosol layers, on the contrary, are more likely to form aquitards. The difference between loess and paleosol in permeability, porosity and groundwater enrichment conditions is largely attributed to lower intensity pedogenesis of loess, which is in turn ascribed to the colder and drier palaeoclimatic conditions. It is worth mentioning that the CaCO3 concretion layer is a good aquifuge for its compact structure. Generally, the empirical formula of the Koctakob formula is applicable for describing the permeability rule of loess and paleosol layers, and the parameters of the empirical formulas can provide an important reference for hydrological and agricultural departments. In this regard, the Quaternary climatic change theory can contribute to the hydrogeology of the Chinese Loess Plateau, and the regional climatostratigraphy can be regarded as a baseline for local water resource positioning and revegetation in such a semi-arid area, which broadens the application field of Quaternary climatic change theory. Meanwhile, it also provides a reference path for solving water shortages of other loess distribution areas in China and other countries.

The Assessment of Sewage Sludge Utilization in Closed-Loop Economy from an Environmental Perspective

“…Soils with low permeability hinder water movement, slowing down the transport of metals into the deeper soil. However, during conditions of excessive irrigation or heavy rainfall, there remains a risk of metals entering groundwater, even in low-permeability soils [33].…”

Quantitative 3D Characterization of Pore Structure in Malan Loess from Different Regions of the Loess Plateau

“…The pores within loess have a considerable effect on its permeability because they provide channels for water seepage [9,16,33]. The relationships between permeability and pore structure, including the void ratio, average CN, µ t describing the throat length and a describing the throat size, are plotted in Figure 11a-d, respectively.…”

A Novel Method for Obtaining the Loess Structural Index from Computed Tomography Images: A Case Study from the Lvliang Mountains of the Loess Plateau (China)

“…The depths of the samples ranged from 3 to 16.5 m to ensure that all the samples were in the Late Pleistocene soil layer. Three typical geological layers consisting of loess soil were selected: L1 (Malan loess layer) [44], S1 (paleosol layer) [45], and L2 (Lishi loess layer) [46], respectively (Supplementary Materials S1). All these three are from the Chinese Soil Taxonomy (CST) [47].…”