泸西喀斯特断陷盆地地表水与地下水流域边界与水动力性质

Watershed boundaries and hydrodynamic properties of surface water and groundwater in the Luxi karst fault-depression basin

在详细调查基础上,采用系统科学及水文地质分析方法,依据地形地貌、地层岩性、地质构造、示踪试验、地下水排泄基准面、喀斯特发育条件及发育规律等剖析论证流域边界,并通过钻探及示踪试验进行验证。研究结果:(1)对泸西喀斯特断陷盆地南东部的水系统边界向北移进行了修正,证实了三塘一带深部不发育的喀斯特是地下水分水岭边界,使得泸西喀斯特断陷盆地流域的径流系统和边界圈化更加准确;(2)泸西喀斯特断陷盆地流域地表水、地下水转化频繁,地表水径流特征主要以小江河在水库、河流、伏流间的径流转化过程为体现,地下水在侵溶山区接受大气降水补给后,上层径流以泉、暗河的形式在泸西盆地底面排泄后转化成地表水,最终汇集于盆地南部、通过工农隧洞及落水洞排向小江,而下层径流则以小江水面为基准,通过深层径流排泄。

The Luxi karst fault-depression basin is located on the marginal slope of the southeast Yunnan plateau and is a tributary on the left bank of the Nanpan river system.It hosts two types of landforms,karst basins and karst river valleys.This basin also lies at the upstream in north,while the Xiaojiang karst river valley is at downstream in the south;both are connected by the underground flow system in the Maoshui cave to form a karst water system with complete recharge,runoff and discharge processes.The watershed boundary and hydrodynamic properties are the most important determinants of the watershed eco-geological environment and water flow characteristics.Accurate determination of the boundary and hydrodynamic properties of surface water and groundwater in the basins is a necessary prerequisite for runoff system simulation,water resource evaluation,searching and utilizing groundwater resources,development and protection planning of resources and environments,solution of environmental problems,and ecological restoration and protection.However,in previous work,the boundary of the groundwater basin divided by the hydrogeological environmental geological survey and evaluation is mainly along the boundary of the surface watershed,aquifer and aquiclude(band,body),most of which are not accurate enough.The hydrodynamic property of the boundary was mainly the result of hydrogeological analysis and inference.In this work,through detailed hydrogeological investigation and analysis,we initially delineated the boundary between surface water and groundwater basins in the Luxi karst fault-depression basin,and then revealed and controlled the hidden and inaccurate sections through drilling,tracer tests,and geophysical surveys,thus making the boundaries of watersheds and water systems revised more accurate.At the same time,we clarified the hydrodynamic properties of watershed boundaries,and obtained basic hydrogeological parameters,so as to provide a basis for model construction and solution conditions to the surface water and groundwater runoff systems in the basin.