thesis:canopy_stream_tracing [Hydro-Wiki ]

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Problemstellung

Stable isotopes of water are one of the most widely used tools to track the pathways of precipitation inputs through soils to streams. In the past, soils have often been treated as black-boxes through which precipitation is routed to streams without much consideration of how, when, and where water is transported along soil water flow paths. In fact, precipitation reaches the forest floor via diffuse (throughfall) and point (stem flow) inputs and throughfall can be highly heterogeneous, partly as a result of variations in canopy coverage and branch architecture.

Ziel der Arbeit

The aim of this thesis is to use stable isotopes of water (²H and ¹⁸O) in precipitation, stem flow, throughfall, soil and stream water to evaluate how fast and with which patterns rainfall events influence the soil and stream water compartments and which role the canopy plays in terms of altering the isotopic input signal and the above-ground water input redistribution. The study will be conducted at a hillslope in the Conventwald, which is an already well-equipped study area located in the central part of the Black Forest mountain range (Wuchsbezirk „Mittlerer Schwarzwald“).

Methode

To track the precipitation isotopic input through the canopy, over the soil to the stream, different types of samplers should be setup and several rainfall events should be monitored. Soil samples should be taken by coring and water extraction should be performed. The isotopic composition of lateral and vertical subsurface flow and streamflow should be monitored. The subsequent isotope analysis will be done in our lab.