Retreating glaciers give way to new landscapes with lakes as an important element.In this study, we combined available data on lake outlines with historical orthoimagery and glacier outlines for six time periods since the end of the Little Ice Age (LIA; $1850). We generated a glacial lake inventory for modern times (2016) and traced the evolution of glacial lakes that formed in the deglaciated area since the LIA. In this deglaciated area, a total of 1192 lakes formed over the period of almost 170 years, 987 of them still in existence in 2016. Their total water surface in 2016 was 6.22 AE 0.25 km 2 . The largest lakes are > 0.4 km 2 (40 ha) in size, while the majority (> 90%) are smaller than 0.01 km 2 . Annual increase rates in area and number peaked in 1946-1973, decreased towards the end of the 20th century, and reached a new high in the latest period 2006-2016. For a period of 43 years , we compared modelled overdeepenings from previous studies to actual lake genesis.For a better prioritization of formation probability, we included glacier-morphological criteria such as glacier width and visible crevassing. About 40% of the modelled overdeepened area actually got covered by lakes. The inclusion of morphological aspects clearly aided in defining a lake formation probability to be linked to each modelled overdeepening. Additional morphological variables, namely dam material and type, surface runoff, and freeboard, were compiled for a subset of larger and ice-contact lakes in 2016, constituting a basis for future hazard assessment.

<p>The deglaciation since the end of the Little Ice Age (LIA, ~1850) has given way to >700km² of “new” landscape in Switzerland. Glacial lakes are a conspicuous feature of this new landscape – with relevance for natural hazards, hydropower and landscape planning. In this study, we compiled an inventory of glacial lakes for Switzerland for the year 2016. Using existing data, we investigated the evolution of glacial lakes in Switzerland for six time periods since the LIA. Additionally, we compiled information constituting a basis for hazard assessment for all ice-contact lakes in 2016 and all lakes >0.5 ha, i.e. surface outflow, dam type and material, and lake freeboard.</p><p>We found that a total of 1230 lakes formed over the period of ~170 years, 982 still existing in 2016. The largest lakes are >0.4 km² (40 ha) in size, while the majority (>90%) are smaller than 0.01 km². Annual increase rates in area and number peaked in 1946-1973, decreased towards the end of the 20<sup>th</sup> century, and reached a new high in the latest period 2006-2016. For a period of 43 years, we compared modelled overdeepenings from previous studies to actual lake genesis. For a better prioritisation of formation probability, we included glacier-morphological criteria such as glacier width and visible crevassing. About 40% of the modelled overdeepened area actually filled with water. The inclusion of morphological aspects clearly aided in linking a lake formation probability to a modelled overdeepening.</p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.d3501255f60064578601161/sdaolpUECMynit/12UGE&app=m&a=0&c=a53c560cf096fb15e526d1d230f3d1bf&ct=x&pn=gnp.elif&d=1" alt="" width="381" height="225"></p><p>Fig. 1: Glacial lake distribution in Switzerland and its evolution over time. </p>

Der SE von Basel gelegene Tafeljura, insbesondere das Gempenplateau, ist von den benachbarten Grossstrukturen Oberrheingraben und Faltenjura tektonisch beeinflusst worden. Mittels eines grossangelegten Tracerversuches, verbunden mit hydrogeologischen Kartierungen und Quellbeobachtungen wurde der Einfluss der resultierenden Störungen des Gesteins (z.B. Zerrklüfte) und des Gesteinsverbandes (Auf-und Abschiebungen) auf die Entwicklung von Karstwassersystemen untersucht. Das Ziel war vor allem, Erkenntnisse, die kürzlich in verkarsteten Antiklinalstrukturen gewonnen wurden, zu verifizieren und zu erweitern. Das Gempenplateau wird von zwei grossen Karstaquiferen charakterisiert, welche durch eine mächtige Aquiklude getrennt sind. Verwerfungen entlang der Rheintalflexur haben örtlich zu direkten Kontakten zwischen den beiden Aquiferen geführt. Der namhafte und schnelle hydraulische Austausch zwischen den beiden Aquiferen belegt, dass Abschiebungen offensichtlich kein Hindernis für die Ausbildung von Karstsystemen darstellen. Weitaus spektakulärer sind allerdings die schnellen und weitreichenden Verbindungen parallel zu den transtensiv beanspruchten Normalbrüchen. Auf entsprechende Strukturen können auch Verbindungen zwischen den beiden Aquiferen zurückgeführt werden, wo kein direkter Kontakt zwischen den beiden besteht (Transport durch die Aquiklude). Anhand eines Diagramms wird versucht, die resultierenden Grössen (scheinbare) Transportdistanz und-geschwindigkeit auf die wichtigsten Komponenten hydraulischer Gradient, Orientierung der Klüftung bzw. der Schichtung und schliesslich Anzahl durchströmter Aquifere, Aquiclude und Störungen zurückzuführen, um so ein generell übertragbares Modell für den Einfluss der Tektonik auf die Grundwasserzirkulation zu erhalten.

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