| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4526267 | Advances in Water Resources | 2010 | 9 Pages |
The biosphere reserve Schorfheide-Chorin is a scenic region with many lakes. Hydraulic coupling between lakes and groundwater is difficult to assess due to the very heterogeneous Pleistocene deposits with a complex layering of different aquifers, part of them being confined. Thus, a principal component analysis of time series of groundwater and lake water levels was performed. The first two principal components provided a quantitative measure of damping of the input signal, i.e., the extent to which time series of groundwater pressure heads or lake water levels are smoothed and delayed with respect to the input signal, i.e., groundwater recharge or precipitation minus evapotranspiration, respectively. The lakes differed substantially with respect to damping behaviour, indicating different impacts of deep groundwater contribution. For most of the groundwater wells, damping increased linearly with mean depth to water table. In contrast, some wells exhibited nearly identical behaviour independent of depth. High-pass filtered data of water table level from these wells were strongly and inversely correlated with those of barometric pressure fluctuations, pointing to a confined aquifer which was evidently not connected to the adjacent lake.
Research Highlights► A new method was developed for assessing hydraulic linkages between lakes and groundwater systems in layered aquifers. In contrast to the common approaches, only very limitd and easy to get data are required that are usually provided by hydrological monitoring programs of water resources agencies. ► A second approach was developed to assess whether a given aquifer is confined or not without requiring any data about the subsurface structure. To that end, hourly data of groundwater heads and atmospheric pressure were used. ► The results of the study revealed that the functional hetereogeneity of the studied aquifer system was much less compared to what was expected based on prior knowledge about structural subsurface heterogeneities.
