Javier Valdes-Abellan

Vinasse application to sugar cane fields. Effect on the unsaturated zone and groundwater at Valle del Cauca (Colombia)

Extensive application of vinasse, a subproduct from sugar cane plantations for bioethanol production, is currently taking place as a source of nutrients that forms part of agricultural management in different agroclimatic regions. Liquid vinasse composition is characterised by high variability of organic compounds and major ions, acid pH (4.7), high TDS concentration (117,416-599,400mgL(-1)) and elevated EC (14,350-64,099μScm(-1)). A large-scale sugar cane field application is taking place in Valle del Cauca (Colombia), where monitoring of soil, unsaturated zone and the aquifer underneath has been made since 2006 to evaluate possible impacts on three experimental plots. For this assessment, monitoring wells and piezometers were installed to determine groundwater flow and water samples were collected for chemical analysis. In the unsaturated zone, tensiometers were installed at different depths to determine flow patterns, while suction lysimeters were used for water sample chemical determinations. The findings show that in the sandy loam plot (Hacienda Real), the unsaturated zone is characterised by low water retention, showing a high transport capacity, while the other two plots of silty composition presented temporal saturation due to La Niña event (2010-2011). The strong La Niña effect on aquifer recharge which would dilute the infiltrated water during the monitoring period and, on the other hand dissolution of possible precipitated salts bringing them back into solution may occur. A slight increase in the concentration of major ions was observed in groundwater (~5% of TDS), which can be attributed to a combination of factors: vinasse dilution produced by water input and hydrochemical processes along with nutrient removal produced by sugar cane uptake. This fact may make the aquifer vulnerable to contamination.

Brackish groundwater desalination by reverse osmosis in southeastern Spain. Presence of emerging contaminants and potential impacts on soil-aquifer media

This study forms part of the CONSOLIDER-TRAGUA and CGL2010-22,168-C03-02/BTE projects financed by the Ministry of Science and Innovation of Spain.

Fate and Transport of Naproxen in a Sandy Aquifer Material: Saturated Column Studies and Model Evaluation

Naproxen-C14H14O3 is a nonsteroidal anti-inflammatory drug which has been found at detectable concentrations in wastewater, surface water, and groundwater. Naproxen is relatively hydrophilic and is in anionic form at pH between 6 and 8. In this study, column experiments were performed using an unconsolidated aquifer material from an area near Barcelona (Spain) to assess transport and reaction mechanisms of Naproxen in the aquifer matrix under different pore water fluxes. Results were evaluated using HYDRUS-1D, which was used to estimate transport parameters. Batch sorption isotherms for Naproxen conformed with the linear model with a sorption coefficient of 0.42 (cm3 g−1), suggesting a low sorption affinity. Naproxen breakthrough curves (BTCs) measured in soil columns under steady-state, saturated water flow conditions displayed similar behavior, with no apparent hysteresis in sorption or dependence of retardation (R, 3.85-4.24) on pore water velocities. Soil sorption did not show any significant decrease for increasing flow rates, as observed from Naproxen recovery in the effluent. Sorption parameters estimated by the model suggest that Naproxen has a low sorption affinity to aquifer matrix. Most sorption of Naproxen occurred on the instantaneous sorption sites, with the kinetic sorption sites representing only about 10 to 40% of total sorption.

Dispersivity Determination Through a Modeling Approach From a Tracer Test Based on Total Br Concentration in Soil Samples

Abstract Determination of reliable solute transport parameters is an essential aspect for the characterization of the mechanisms and processes involved in solute transport (e.g., pesticides, fertilizers, contaminants) through the unsaturated zone. A rapid inexpensive method to estimate the dispersivity parameter at the field scale is presented herein. It is based on the quantification by the X-ray fluorescence solid-state technique of total bromine in soil, along with an inverse numerical modeling approach. The results show that this methodology is a good alternative to the classic Br− determination in soil water by ion chromatography. A good agreement between the observed and simulated total soil Br is reported. The results highlight the potential applicability of both combined techniques to infer readily solute transport parameters under field conditions.

Predicting Daily Water Table Fluctuations in Karstic Aquifers from GIS-Based Modelling, Climatic Settings and Extraction Wells

In semiarid regions, karstic aquifers are in some cases essential since they often constitute the only source of water supply. The increasing demand for water in these regions is responsible for the decreasing water table levels. As a consequence, groundwater management becomes indispensable. A robust black-box model of the Solana aquifer, a large karstic aquifer in Alicante province, is developed considering GIS-based modelling of the studied area, climatic settings and anthropic disturbances (water extractions and irrigation returns). The proposed model accurately predicts water table levels evolution (with EF index of 0.97 and RMSE of 0.09) and assesses the recharge rates. The model aims to become a useful tool in order to better understand the characteristics of karstic aquifers. A distinctive feature of the model is that it estimates the heterogeneous effective porosities along the depth profiles of the aquifer, which provides an advantage related to detect changes in the hydraulic transmissivity within karstic formations.

MATLAB algorithm to implement soil water data assimilation with the Ensemble Kalman Filter using HYDRUS

Graphical abstract

Temporal evolution of urban growth and its impact on runoff rates generation

Financial support was provided partially by the University of Alicante, project GRE15-19. This study also has been conducted within the grant received from the Programa Nacional de Formacion de Profesorado Universitario (FPU) conceded by the Spanish Ministry of Science to the first author.

Validating the KAGIS black-box GIS-based model in a Mediterranean karst aquifer: Case of study of Mela aquifer (SE Spain)

This research was funded by the Spanish Ministry of Science and Innovation, Projects CGL2013‐48802‐C3‐3‐R and CGL2015‐69773‐C2‐1‐P; and by the University of Alicante, Projects GRE15‐19 and GRE17‐12.