Centre for Hydrogeology and Geothermics (Chyn), University of Neuchâtel, Rue Emile-Argand 11, CH-2000, Neuchâtel, Switzerland.
Ground Water. 2023 Jan;61(1):111-118. doi: 10.1111/gwat.13218. Epub 2022 Jun 24.
Karst aquifers are a groundwater resource of global importance. Protection and contamination of karst water resources are often tackled by means of land-use planning and monitoring of physico-chemical and microbial water properties coupled to early-warning systems. However, these solutions of management do not integrate observational data on karst hydrodynamic, for example, tracer tests. Thus, this technical note aims at introducing a straightforward method for forecasting the arrival time of a tracer or a pollutant at a karst spring. Deliverables from the proposed method can assist professionals in the case of a pollution involving a swallow hole of the karst network. The approach is based on repeated tracer testing, gauging of spring flow rate and mathematical curve fitting. Tracer tests and gauging of spring flow rates are repeated under low, middle, and high flow periods. Arrival times of tracer from a given swallow hole of the network are plotted as a function of measured flow rates at the karst spring. The observational data are finally fitted by a mathematical function. Flow rate monitoring at high-temporal resolution at the karst spring and the mathematical functions allow forecasting the arrival of a tracer or a pollutant at the spring in the case of an accident involving a swallow hole of the network or estimating the duration of a pollution if hydrodynamic conditions do not change abruptly. The applicability of the method is documented by three study sites in Switzerland.
喀斯特含水层是具有全球重要意义的地下水资源。保护和污染喀斯特水资源通常通过土地利用规划和监测物理化学和微生物水特性以及预警系统来解决。然而，这些管理解决方案并未整合有关喀斯特水动力的观测数据，例如示踪剂测试。因此，本技术说明旨在介绍一种简单的方法，用于预测示踪剂或污染物到达喀斯特泉的时间。所提出方法的成果可以在涉及喀斯特网络的落水洞污染的情况下为专业人员提供帮助。该方法基于示踪剂测试、泉流量测量和数学曲线拟合的重复进行。在低、中和高流量期重复进行示踪剂测试和泉流量测量。将网络中给定落水洞的示踪剂到达时间绘制为喀斯特泉的实测流量函数。最后，通过数学函数对观测数据进行拟合。如果水动力条件没有急剧变化，泉的高时间分辨率流量监测和数学函数可以预测在涉及网络落水洞的事故中示踪剂或污染物到达泉的时间，或者估计污染的持续时间。该方法的适用性通过瑞士的三个研究地点得到证明。
