[Introduction]: From the Los Laureles reservoir it is generated an enormous amount of water quality data that are often not analysed and interpreted in a comprehensive manner, a limitation that also occurs in others reservoirs in the country and over the Central American region. This situation limits the knowledge for taking preventive actions in the face of contamination scenarios when the parameters are observed or analysed separately. [Objective]: The purpose of the research was to calculate and use different water quality indices in the Los Laureles reservoir during the time 2002-2016 with historical data, and analyse possible natural or anthropic factors that have contributed to its deterioration. [Methodology]: The indices were calculated using WQI software (version 1.2), based on historical information generated by the SANAA Laboratory at three sampling points (curtain, centre and tail), and including up to 23 physicochemical, microbiological, metals and metalloids parameters. Three different guidelines were used: one guideline of water quality for human consumption use and two guidelines for water life protection use. [Results]: The quality indices categorized the water quality of the Los Laureles reservoir for the use of human consumption as marginal to poor. The categorisation of use for aquatic life protection was regular. The decrease in the values of the indices and the categorization of water quality was observed when more parameters and samplings were included. [Conclusion]: In the comprehensive study, a historical decrease in quality was recorded due to the increase in the values of the parameters that exceeded the guidelines up to more than 25 times, even when it is only a parameter that will contribute to its decrease. In other words, the number of times that a parameter exceeded the guidelines had more influence than the number of failed parameters. | [Introducción]: Del embalse Los Laureles se genera una enorme cantidad de datos de calidad de agua que muchas veces no es analizada e interpretada de manera integral, deficiencia que se observa en otros embalses en el país y de la región centroamericana. Esto provoca un conocimiento limitado que impide tomar acciones preventivas ante escenarios de contaminación cuando se observan o analizan los parámetros por separado. [Objetivo]: El propósito de la investigación fue calcular e interpretar diferentes índices de calidad del agua en el embalse Los Laureles durante el periodo 2002-2016 con datos históricos y generados en este estudio para analizar los posibles factores naturales o antrópicos que han contribuido al deterioro de su calidad. [Metodología]: Los índices se calcularon utilizando el software WQI versión 1.2 a partir de información histórica generada por el Laboratorio del SANAA en tres puntos de muestreo (cortina, centro y cola) e incluyendo hasta 23 parámetros fisicoquímicos, microbiológicos, metales y metaloides. Se utilizaron tres directrices de calidad: una para uso de consumo humano, y dos para uso de protección de la vida acuática. [Resultados]: Los índices de calidad categorizaron la calidad del agua del embalse Los Laureles para el uso consumo humano de marginal a pobre; mientras que para el uso protección de la vida acuática como regular. Se observó una disminución en los valores de los índices y en la categorización de la calidad del agua cuando se incluyeron más parámetros y muestreos. [Conclusiones]: En el estudio integral se observó una disminución histórica de la calidad por el aumento en los valores de los parámetros que sobrepasaron las directrices hasta más de 25 veces, aún cuando solo se tratara de un parámetro que contribuyera a su disminución. Es decir, influyó más la cantidad de veces que un parámetro sobrepasó la norma que el número de parámetros fallidos. | [Introdução]: Uma enorme quantidade de dados de qualidade da água é gerada a partir do reservatório Los Laureles que muitas vezes não é analisada e interpretada de forma abrangente, uma deficiência observada em outros reservatórios do país e na região da América Central. Isso provoca um conhecimento limitado que impede a tomada de ações preventivas diante de cenários de contaminação quando os parâmetros são observados ou analisados ​​separadamente. [Objetivo]: O objetivo da pesquisa foi calcular e interpretar diferentes índices de qualidade da água no reservatório Los Laureles durante o período de 2002-2016 com dados históricos gerados neste estudo para analisar os possíveis fatores naturais ou antrópicos que contribuíram para a deterioração de sua qualidade. [Metodologia]: Os índices foram calculados utilizando o software WQI versão 1.2 a partir de informações históricas geradas pelo Laboratório SANAA em três pontos de amostragem (cortina, centro e cauda) e incluindo até 23 parâmetros físico-químicos, microbiológicos, de metais e metalóides. Três diretrizes de qualidade foram utilizadas: uma para uso para consumo humano e duas para uso na proteção da vida aquática. [Resultados]: Os índices de qualidade categorizaram a qualidade da água do reservatório Los Laureles para consumo humano de marginal a pobre; enquanto para proteção de vida aquática use como regular. Uma diminuição nos valores dos índices e na categorização da qualidade da água foi observada quando mais parâmetros e amostragens foram incluídos. [Conclusões]: No estudo abrangente, observou-se uma diminuição histórica da qualidade devido ao aumento dos valores dos parâmetros que ultrapassaram as diretrizes em mais de 25 vezes, mesmo quando foi apenas um parâmetro que contribuiu para sua diminuir. Em outras palavras, o número de vezes que um parâmetro excedeu a norma teve mais influência do que o número de parâmetros com falha.

El agua es fuente y motor de vida en el planeta, la calidad y disponibilidad del mismo, representa el consumo y abastecimiento para las actividades cotidianas del hombre, logrando un crecimiento económico y bienestar común. Colombia país catalogado por tener una gran riqueza hídrica, experimenta una crisis asociada a la escases del recurso, resultado del aumento de la necesidad de consumo, bien sea por el crecimiento demográfico o por el desperdicio del mismo que se presenta, otro factor que influye es la disminución de la oferta, ya que ésta depende de la cantidad de agua disponible, afectada por su distribución y su baja calidad. Ante toda esta problemática, el gobierno busca garantizar la sostenibilidad del agua a través de la llamada gestión del recurso hídrico, dándole participación a los Planes de Uso Eficiente y Ahorro de Agua- PUEAA, como herramienta de prevención, control y reporte del estado actual a nivel local y regional. En la contribución con el mejoramiento en la gestión desde la Orinoquia, se realiza la guía que permite orientar a las empresas de servicio de acueducto y alcantarillado, en la elaboración de los Planes de Uso eficiente y Ahorro de Agua PUEAA, donde posteriormente serán aprobadas por el ente regulador regional CORPORINOQUIA y reportadas a nivel nacional, con el fin de evaluar la situación del país en este aspecto y generar estrategias requeridas para su mejoramiento. Para la construcción de la guía se tomó como estudio de caso el municipio de Pore, ya que presenta un nivel de cumplimiento del 80% de los requerimientos de la autoridad ambiental. Posteriormente se identificaron las debilidades y se realizaron sugerencias para que a través de la implementación de la metodología de Marco Lógico publicada por la CEPAL, se complementara el plan del municipio y se pueda alcanzar un mayor nivel de cumplimiento con su aplicación. | Ingeniero Ambiental | Pregrado | Water is the source and engine of life on the planet, the quality and availability of water represents the consumption and supply for the daily activities of man, achieving economic growth and common welfare. Colombia, a country catalogued for having a great water wealth, is experiencing a crisis associated with the scarcity of the resource, as a result of the increase in the need for consumption, either by population growth or by the waste of it, another factor that influences is the decrease in supply, since it depends on the amount of water available, affected by its distribution and its low quality. Faced with all these problems, the government seeks to guarantee the sustainability of water through the so-called water resource management, giving participation to the Plans for Efficient Use and Saving of Water - PUEAA, as a tool for prevention, control and reporting of the current state at local and regional level. In order to contribute to the improvement of management in the Orinoco region, a guide was prepared to guide water and sewage service companies in the preparation of Water Efficient Use and Saving Plans (PUEAA), which will later be approved by the regional regulatory body CORPORINOQUIA and reported at the national level, with the purpose of evaluating the country's situation in this aspect and generating strategies required for its improvement. For the construction of the guide, the municipality of Pore was taken as a case study, since it has an 80% compliance level with the requirements of the environmental authority. Subsequently, weaknesses were identified and suggestions were made so that through the implementation of the Logical Framework methodology published by ECLAC, the municipality's plan could be complemented and a higher level of compliance could be achieved with its application.

A coupled groundwater-flow-modelling and vulnerability-mapping methodology for the management of karst aquifers with spatial variability is developed. The methodology takes into consideration the duality of flow and recharge in karst and introduces a simple method to integrate the effect of temporal storage in the unsaturated zone. In order to investigate the applicability of the developed methodology, simulation results are validated against available field measurement data. The criteria maps from the PaPRIKa vulnerability-mapping method are used to document the groundwater flow model. The FEFLOW model is employed for the simulation of the saturated zone of Palaikastro-Chochlakies karst aquifer, in the island of Crete, Greece, for the hydrological years 2010–2012. The simulated water table reproduces typical karst characteristics, such as steep slopes and preferred drain axes, and is in good agreement with field observations. Selected calculated error indicators—Nash-Sutcliffe efficiency (NSE), root mean squared error (RMSE) and model efficiency (E′)—are within acceptable value ranges. Results indicate that different storage processes take place in different parts of the aquifer. The north-central part seems to be more sensitive to diffuse recharge, while the southern part is affected primarily by precipitation events. Sensitivity analysis is performed on the parameters of hydraulic conductivity and specific yield. The methodology is used to estimate the feasibility of artificial aquifer recharge (AAR) at the study area. Based on the developed methodology, guidelines were provided for the selection of the appropriate AAR scenario that has positive impact on the water table.

Intensification of potato farming has contaminated groundwater with nitrate in many cases in Prince Edward Island, Canada, which raises concerns for drinking water quality and associated ecosystem protection. Numerical models were developed to simulate nitrate-N transport in groundwater and enhance understanding of the impacts of farming on water quality in the Wilmot River watershed. Nitrate is assumed non-reactive based on δ¹⁵N and δ¹⁸O in nitrate and geochemical information. The source functions were reconstructed from tile drain measurements, N budget and historical land-use information. The transport model was calibrated to long-term nitrate-N observations in the Wilmot River and verified against nitrate-N measurements in two rivers from watersheds with similar physical conditions. Simulations show groundwater flow is stratified and vertical flux decreases exponentially with depth. While it would take several years to reduce the nitrate-N in the shallow portion of the aquifer, it would take several decades or even longer to restore water quality in the deeper portions of the aquifer. Elevated nitrate-N concentrations in base flow are positively correlated with potato cropping intensity and significant reductions in nitrate-N loading are required if the nitrate level of surface water is to recover to the standard in the Canadian Water Quality Guidelines.

Geochemical and isotopic characterization of groundwater and lake-water samples were combined with water and total dissolved solids balances to evaluate sources of groundwater quality deterioration in eastern Hetao Basin, Inner Mongolia, China. Groundwater quality is poor; 11 of 13 wells exceed drinking-water guidelines for at least one health-based parameter and all wells exceed aesthetic guidelines. The well water is largely derived from Yellow River irrigation water. Notably high uranium concentrations in the Yellow River, relative to world rivers, suggest groundwater uranium and other trace elements may originate in the river-derived irrigation water. Complex hydrostratigraphy and spatial variation in groundwater recharge result in spatially complex groundwater flow and geochemistry. Evapotranspiration of irrigation water causes chloride concentration increases of up to two orders of magnitude in the basin, notably in shallow groundwater around Wuliangsuhai Lake. In addition to evapotranspiration, groundwater quality is affected by mineral precipitation and dissolution, silicate weathering, and redox processes. The lake-water and TDS balances suggest that a small amount of discharge to groundwater (but associated with very high solute concentrations) contributes to groundwater salinization in this region. Increasing salinity in the groundwater and Wuliangsuhai Lake will continue to deteriorate water quality unless irrigation management practices improve.