Abstract

The efficiency of artificial surface ponds (SPs) for managed aquifer recharge (MAR) is mostly controlled by the topmost portion of the soil. The most significant soil property controlling recharge is the infiltration capacity (I_c), which is highly variable in space. Assessing its spatial distribution in detail is prohibitive in practice due to high costs, time effort, and limited site accessibility. We present an alternative method for a quick and low-cost quantitative estimation of the spatial distribution of I_c based on satellite images. The fact that hydraulic properties of topsoils and color intensities of digital images depend on some common factors such as moisture content, nature and organization of grains, proportion of iron, and organic and clay content among others, allow us to infer infiltration capacities from color intensities. The relationship between these two variables is site specific and requires calibration. A pilot SP site in Catalonia (Spain) is used as an application example. Two high-resolution digital images of the site are provided at no cost by the local cartographic institute as well as from a popular Internet-based map server. An initial set of local infiltration experiments, randomly located, were found to correlate to color intensities of the digital images. This relationship was then validated against additional independent measurements. The resulting maps of infiltration were then used to estimate the total maximum infiltration of the artificial pond area, the results being consistent with an independent flooding test performed at the site.

Abstract

In order to study the characteristics of spatial variability of soil infiltration in the aeolian sandy land improvement and utilization area, this paper conducted a study on the six different land use types in the aeolian sandy land in northwest Liaoning by means of average and random distribution. With bare land as the control group, the physical parameters of the soil in the test area were analyzed and processed through traditional statistical analysis and geostatistical analysis, and the spatial distribution of various physical parameters was studied using ordinary Kriging interpolation. The results show that the bulk density of different land use types in the aeolian sandy land improvement and utilization area in northwestern Liaoning has been reduced, and the total porosity, capillary porosity, water content and the ratio of clay particles have increased to varying degrees. Soil infiltration has a negative correlation with moisture content and clay particles, and a positive correlation with the ratio of total porosity. In addition, among all types of improved utilization, other forest land has the largest infiltration and the research land has the smallest one.