Tesis Doctoral/PHD

Permanent URI for this collectionhttps://dspace-test.ucuenca.edu.ec/handle/123456789/24267

Browse

Browsing Tesis Doctoral/PHD by Author "Birkel, Christian"

Filter results by typing the first few letters
Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Bridging the gap between hydrological and biogeochemical processes in a high Andean catchment: a comprehensive tracer-aided model framework
    (Universidad de Cuenca, 2023-09-29) Pesántez Vallejo, Juan Patricio; Crespo Sánchez, Patricio Javier; Birkel, Christian; Célleri Alvear, Rolando Enrique
    The Andean mountains satisfy the vital needs of the Andean population and its lowlands. However, they are projected to experience significant impacts attributed to land-use change and climate change. Despite our understanding of the hydrology in these areas, to date, there has been no modeling framework that incorporates direct data acquisition, simple models, and extends to a distributed modeling framework. Such a framework should be able to elucidate hydrological and biogeochemical processes in a manner comprehensible to decision-makers. Therefore, the primary objective of this thesis is to spatially and temporally assess the production and distribution of water and dissolved organic carbon (DOC) in a páramo catchment using tracer-aided models. To achieve this, we have monitored hydrometeorological and biogeochemical parameters, as well as water stable isotopes. In combination with field observations and perceptual knowledge of these catchments, we evaluated them within a comprehensive hydrological modeling framework. We found that DOC and other solutes can be estimated through in-situ spectrometry. Using these solutes as tracers made it possible to compare different hydrological pathways and was the only way to identify that streamflow response consisted of near-surface rapid flow, more mixed flow through the two main soil types, as well as flow from shallow fractured rock, especially under base flow conditions. Based on the hydrological processes found, a new module was developed to simulate DOC production and incorporate it into a spatially distributed hydrological model at a high spatial (10 x 10 meters) and temporal (1 hour) resolution. This model allowed us to identify DOC hots pots and hot moments. The results showed increased hydrological connectivity between hillslopes and valleys with increasing precipitation. Wetter conditions also favored DOC production, especially in valleys (Histosols), and DOC transport to the river. Our findings suggest that minor changes in meteorological conditions directly affect water dynamics in páramo soils and its biogeochemistry. These conclusions will enable informed decisions to be made regarding water security, taking into account the effect of carbon loss from the soils to the rivers in the páramo.