Characterizing hydrological processes within kettle holes using stable water isotopes in the Uckermark of northern Brandenburg, Germany

Abstract

Understanding the hydrologic connectivity between kettle holes and shallow groundwater, particularly in reaction to the highly variable local meteorological conditions, is of paramount importance for tracing water in a hydro(geo)logically complex landscape and thus for integrated water resource management. This article is aimed at identifying the dominant hydrological processes affecting the kettle holes' water balance and their interactions with the shallow groundwater domain in the Uckermark region, located in the north-east of Germany. For this reason, based on the stable isotopes of oxygen (δ 18 O) and hydrogen (δ 2 H), an isotopic mass balance model was employed to compute the evaporative loss of water from the kettle holes from February to August 2017.Results demonstrated that shallow groundwater inflow may play the pivotal role in the processes taking part in the hydrology of the kettle holes in the Uckermark region.Based on the calculated evaporation/inflow (E/I) ratios, most of the kettle holes (86.7%) were ascertained to have a partially open, flow-through-dominated system. Moreover, we identified an inverse correlation between E/I ratios and the altitudes of the kettle holes. The same holds for electrical conductivity (EC) and the altitudes of the kettle holes. In accordance with the findings obtained from this study, a conceptual model explaining the interaction between the shallow groundwater and the kettle holes of Uckermark was developed. The model exhibited that across the highest altitudes, the recharge kettle holes are dominant, where a lower ratio of E/I and a lower EC was detected. By contrast, the lowest topographical depressions represent the discharge kettle holes, where a higher ratio of E/I and EC could be identified. The kettle holes existing in between were categorized as flow-through kettle holes through which the recharge takes place from one side and discharge from the other side. K E Y W O R D S evaporation, groundwater inflow, kettle hole, stable water isotope, surface-groundwater interactions

Insights into Shallow Freshwater Lakes Hydrology in the Yangtze Floodplain from Stable Water Isotope Tracers

“…Code 13 (Zhu L.) underwent rapid drainage due to floodplain lake fishing in January. A possible cause of seasonal variation in E/I ratios may be attributed to an increase in air temperature and precipitation amount in May [41]. A similar phenomenon was found by Cui et al (2018) [48] showing that seasonal variations in E/I ratios of Cona lake were associated with interannual meteorological conditions.…”

“…The slope of LEL varying from 4 to 6 depends on the local climatic and environmental conditions such as relative humidity [34,40]. The similar and lower slopes of LEL are observed in January and May, which is associated with strong evaporation [41,42]. In addition, the d-excess of lake water exhibited lower values than the global average of 10‰ (Figure 4), which suggested lake water experienced evaporation in January and May along the mid-lower reaches of Yangtze River.…”

Representation of hydrological processes in a rural lowland catchment in Northern Germany usingSWATandSWAT+

“…However, little is known about to what extent they contribute to retention of water in the landscape and a slow release during low flow periods. Vyse et al (2020) conclude from their study of ponds in the northeast of Germany that the interactions of ponds with the shallow groundwater table should be analysed with the help of hydrologic models. Ongoing measurements of these ponds in the Kielstau catchment offer an opportunity to do so in the future (Ulrich et al, 2019).…”

An AHP based approach to forecast groundwater level at potential recharge zones of Uckermark District, Brandenburg, Germany

“…Uckermark’s regional groundwater structure is aligned with the Pleistocene glacial landscape, with different regional groundwater systems being delineated on the basis of large geomorphological structures such as glacial valleys, till upland regions and end moraines. Sediment types deposited over the study area consist of a range of clastic sediments of glacial fluvial origin and till 27 , 28 .…”