Mayaud Cyril, Wagner Thomas, Benischke Ralf, Birk Steffen
Institute for Earth Sciences, University of Graz, Heinrichstraße 26, 8010 Graz, Austria.
Department of Water Resources and Environmental Analytics, Institute for Water, Energy and Sustainability, Joanneum Research Forschungsgesellschaft mbH, Elisabethstraße 18/II, 8010 Graz, Austria.
Carbonates Evaporites. 2016;31(4):357-365. doi: 10.1007/s13146-013-0172-3. Epub 2013 Oct 4.
A thorough data analysis combined with groundwater modelling was conducted in an Austrian binary karst aquifer to better understand changes in the hydrological behaviour observed at a karst spring. During a period of 4 years after a major flood event the spring hydrograph appears to be more damped with lower peak flow and higher baseflow than in the years before. The analysis of the hydrograph recession suggests that the observed hydrological change is caused by changes within the karst system rather than by varying hydro-meteorological conditions. The functioning of the aquifer and potential causes of the observed changes are further examined using the groundwater flow model MODFLOW. The simulation results suggest that a modification of hydraulic conductivity and storage within the conduit network, e.g. due to the plugging of the drainage conduits with sediments, may be the cause of the different behaviour. MODFLOW was able to reproduce the observed dynamics of spring flow, although it does not account for turbulent flow within karst conduits. Using a simplified model scenario it is demonstrated that the damping of the hydrograph is much stronger if turbulent conduit flow is taken into account. Thus, a turbulent flow model is needed to assess potential changes in the storage properties quantitatively.
在奥地利的一个二元岩溶含水层中，进行了全面的数据分析并结合了地下水建模，以更好地理解在岩溶泉观测到的水文行为变化。在一次重大洪水事件后的4年期间，泉水流量过程线似乎比之前几年更平缓，峰值流量更低，基流更高。对流量过程线消退的分析表明，观测到的水文变化是由岩溶系统内部的变化引起的，而不是由变化的水文气象条件导致的。使用地下水流动模型MODFLOW进一步研究了含水层的功能以及观测到的变化的潜在原因。模拟结果表明，例如由于排水管道被沉积物堵塞，导致管道网络内水力传导率和储水量的改变，可能是行为差异的原因。尽管MODFLOW没有考虑岩溶管道内的紊流，但它能够再现观测到的泉水流量动态。通过一个简化的模型情景表明，如果考虑管道紊流，流量过程线将更平缓。因此，需要一个紊流模型来定量评估储水特性的潜在变化。
