贵州印江朗溪岩溶槽谷龙洞湾泉流量衰减分析

文章对贵州省印江县朗溪隔槽式向斜岩溶槽谷轴面南东侧的龙洞湾岩溶泉流量衰减规律进行了分析，通过在泉口设置复合堰、安放水文气象自动监测仪，获取了该泉降雨量和相对水位的高时间分辨率监测数据，并采用水力学公式计算了泉流量，分析了降雨过后岩溶泉流量的动态特征，再利用分区间指数函数衰减方程确定了该泉所在含水介质的结构特征及亚储水量，结果发现:（1）龙洞湾泉流量峰值滞后时间受降雨过程特征影响较大，当降雨量大或前期有降雨影响时，滞后时间短；当降雨量小或前期无降雨影响时，滞后时间长；（2）强降雨后，龙洞湾泉流量的衰减可分为三个亚动态，且衰减系数的差异较大，第I亚动态和第II亚动态的衰减系数分别是第III亚动态的11倍和3倍，这表明其三重岩溶含水介质的特征明显；（3）龙洞湾泉的含水介质具有不均匀性，以管道流和裂隙流为主，岩溶发育强烈。 

Recession flow analysis for Longdongwan spring at Langxi karst valley in Yinjiang county, Guizhou Province

Longdongwan karst spring is situated in Langxi town, Yinjiang Tujia and Miao Autonomous county, Tongren City, Northeastern Guizhou Province, China. The karst spring occurs on the south-east side of the axis of Langxi trough-like syncline valley, which is a fault spring formed by partial water-resisting section of compressive-torsional faults to prevent groundwater from overflowing. The objective of this study is to understand the aquifer structure of high-level karst springs in the upper part of the mountain in karst valley area, so as to provide scientific basis for management and rational utilization of high-level karst springs in karst valley area. The high-resolution automatically recorded rainfall and water level data from the spring have been collected by using compound weir and automatic hydro-meteorological monitor. The spring flow rate is calculated by hydraulic equations. The characteristics of the flow regime of the karst spring are analyzed. The karst aquifer structure and sub-water storage are estimated by recession flow analysis based on interval exponential function. It is found that, (1) The time lag between peaks of rainfall intensity and flood is strongly affected by the curve shape of the rainfall intensity. The time lag will be short if there is heavy rainfall or previous rainfall influence. Inversely, it will be long if there is small rainfall or little previous rainfall influence.(2) After heavy rainfall event, the natural recession flow of the Longdongwan karst spring has 3 sub-regimes, and the recession coefficients are distinctly different. The recession coefficient of Stage I and Stage II is 11 times and 3 times as large as that of Stage III respectively, indicating that the characteristics of triple carbonate rock medium are obvious.(3) The aquifer medium of the Longdongwan karst spring is heterogeneous due to strong karst processes. The groundwater is dominated by conduit and fissure flows.