Subjects: Geosciences >> Geography submitted time 2023-12-16 Cooperative journals: 《干旱区研究》
Abstract： Based on precipitation and soil water isotope data at different elevations in the north and south mountains of Lanzhou from April to October 2018, the lc-excess method and the lc-excess equilibrium equation were used to qualitatively and quantitatively analyze the soil water infiltration process in this area. The infiltration process of soil water, indicated by the soil water lc-excess value, was verified by correlation analysis and single factor analysis. The results showed that there are obvious variations in soil water content in the study area on a monthly scale and at different depths, with loss dominating from April to June and accumulation dominating from July to September. The soil water content in the high altitude areas was found to be greater than that in the low altitude areas, and the soil water content in the north mountains was found to be greater than that in the south mountains. Stable isotopes of soil water at each sampling site we found to be most depleted from August to September. At increasing soil depth, soil water isotopes showed a trend of gradual depletion and stabilization. The soil water lc-excess results showed that the piston flow mode and the priority flow mode coexist in the infiltration and recharge process of soil water in the study area. The priority flow signal appeared at all sampling sites from July to August. The contribution of the preferred flow pattern to deep soil water was higher at the low elevation sampling sites than at the high elevation sampling sites. The soil water content and soil water lc-excess were found to be positively correlated. The monthly scale and depth of soil water lc-excess were not significantly different between the north and south mountain, indicating that the infiltration and recharge patterns of soil water in the north and south mountains are the same, and that both are dominated by the piston flow infiltration pattern of precipitation recharge. However, in the south mountains, where there is greater vegetation cover, the preferential flow pattern signal appeared more often, especially in July and August, when precipitation is concentrated. Based on the soil water infiltration and replenishment processes in the north and south mountains, it the selection of salt- and drought- tolerant, shallow- rooted shrubs and perennial grasses is recommended for the north mountains, while reasonable irrigation is recommended in the south mountains during the plant growing season (from April to June). The results of this study provide a theoretical reference for understanding the hydrological process in the north and south mountains of Lanzhou.
Subjects: Geosciences >> Hydrology submitted time 2021-10-10 Cooperative journals: 《干旱区地理》
Abstract： 以兰州市安宁区金牛街码头附近距黄河约 10 m 的河漫滩为研究对象，对河漫滩土壤水的 氢氧稳定同位素进行分析并结合不同水体 lc-excess（Line-conditioned excess），研究了河漫滩土壤剖 面不同深度土壤水氢氧稳定同位素与土壤含水量的变化特征以及降水以活塞流、优先流模式对土 壤水的补给过程。研究表明：（1）兰州当地大气降水线（Local meteoric water line，LMWL）：δD=7.00 δ18O+3.81(R2=0.95，P80 cm）土壤水存在补给。（3）4、6、10 月观察到降水以活塞流模式对土壤 水进行了补给，5、9 月观察到降水以优先流模式对土壤水进行补给，即降水对河漫滩土壤水以 2 种 入渗模式共同补给。明晰土壤水特征对于准确分析降水在土壤中的入渗量、深入认识其补给过 程、准确评价地下水补给资源以及地下水污染分析具有重要意义。
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