Identification of hydrologic and geochemical pathways using high frequency sampling, REE aqueous sampling and soil characterization at Koiliaris Critical Zone Observatory, Crete

Koiliaris River watershed is a Critical Zone Observatory that represents severely degraded soils due to intensive agricultural activities and biophysical factors. It has typical Mediterranean soils under the imminent threat of desertification which is expected to intensify due to projected climate change. High frequency hydro-chemical monitoring with targeted sampling for Rare Earth Elements (REE) analysis of different water bodies and geochemical characterization of soils were used for the identification of hydrologic and geochemical pathways. The high frequency monitoring of water chemical data highlighted the chemical alterations of water in Koiliaris River during flash flood events. Soil physical and chemical characterization surveys were used to identify erodibility patterns within the watershed and the influence of soils on surface and ground water chemistry. The methodology presented can be used to identify the impacts of degraded soils to surface and ground water quality as well as in the design of methods to minimize the impacts of land use practices.