Recharge Processes and Water Resources Management: Case Study, Riobamba Aquifer in the Tropical Andes Modeling Flow and Transport Processes in Cold Region Subsurface Environments: Case Study in the Qilian Mountains

Carla Manciati Jaramillo

Biografy. I am Assistant Professor in the Civil and Environmental Engineering Department in the Escuela Poiltécnica Nacional in Quito – Ecuador. I got my PhD in Hydrogeology at the Université de Montpellier in France in 2014, which mainly focused on the comprehension of the hydrological processes of an aquifer system in the Interandean Valley using hydrodynamics and classic and isotopic geochemitry. Currently, I teach Groundwater Hydraulics to the undergrads and Groundwater hydrodynamics and Geochemistry to the grad students. I lead some research projects in the aquifer system of the Chambo river, in the Central Interandean Valley, working with the Instituto Nacional de Meteorología e HidrologÍa (INAMHI), the Universidad Nacional de Chimborazo (UNACH) and the Institut de Recherche pour le Développement (IRD) from France, and also with the University of Minnesota. I also work with the VLIR Network coordinating a Masters program and in other research projects. Currently I was designated as a Chair of Department in the Faculty.

Abstract. The Aquifer of Riobamba is located at the Chambo River Basin, located in the Ecuadorian Interandean Valley. It is a complex volcano-sedimentary system, in a very active tectonic area where all the territory is fractured and also the Pallatanga suture is visible (geologic structure formed from the accreted terrains when de continental Ecuador was created). The study area is surrounded for multiple active volcanos. This aquifer system is the only source of potable and irrigation water for the city of Riobamba (240000 inhabitants) which its main economic activity is agriculture. The aim of this study is to understand the recharge processes of the aquifer system, characterizing its geology and to comprehend the chemistry acquisition of water interacting with surface water, geothermal systems due of active volcanos and deep fractures. In order to achieve this goal, we did some major ions, trace elements and stable isotopes analysis. It was possible to identify three multilayer aquifers, with an origin volcano-sedimentary (Llío-Guano, Riobamba and Yaruquíes) composed by volcanic deposits from Chimborazo, Igualata, and El Altar. These aquifers are fed mainly by two mountain ranges; from the west (Chimborazo and Igualata volcanos) and from the east (El Altar volcano). The recharge has also a secondary contribution from local precipitation. The Chambo river becomes the main discharge of the surface flow and groundwater.

Xiaofan Yang

Biosketch: Xiaofan Yang is a Professor in Hydrology at the Beijing Normal University (BNU), China. She holds a BEng from Tsinghua University (China), a MSc from KTH (Sweden) and a PhD from Kansas State University (USA). Before joining BNU, she was a Scientist at the Pacific Northwest National Laboratory (PNNL) of the U.S. Department of Energy (US DOE). Her research interests include subsurface hydrology, computational hydrology and multiscale modeling and simulations, with specific focus on reactive transport modeling, groundwater modeling, flow and reactive transport in porous media. She is currently the Vice President of the Terrestrial Working Group of the International Arctic Science Committee, member of the National Chapter Committee of the InterPORE, and serves as the Associate Editor of Journal of Hydrology: Regional Studies and Hydrological Processes.

Abstract: Thermo-hydrologic (TH) processes in frozen soils are prominent for improving the mechanistic understanding of subsurface hydrology in cold regions, which are extremely sensitive to seasonal and climate change. Unfortunately, due to the harsh natural environment, it is difficult to obtain long-term and high-resolution datasets via field observations. Numerical modeling and simulation could serve as a powerful tool to improve a predictive understanding of the TH processes in frozen soils. In this talk, we present an in-house developed physically-based cryo-hydrogeological model for simulating TH processes in frozen soils, which was implemented into an open-source, massively-parallel computational fluid dynamics (CFD) software with a user-friendly interface. As validations, a series of benchmarking cases and laboratory freezing experiment were applied to validate the accuracy of the proposed model. The proposed model was then applied to simulate the TH processes in the frozen soils of a small catchment of the Qilian Mountain on the edge of the Qinghai-Tibet Plateau. The trends of the dynamic multiphase flow, ice-water phase transition and heat transfer in seasonally frozen soils were highly consistent with field observations. The effects of seasonal change, slope aspect and micro-topography on the TH processes were diagnosed. The proposed model and the major findings of this research could provide scientific support for predicting changes in subsurface environments of cold regions.

Additional Information:

Register here »