In this paper, we have evaluated high-resolution spatial gridded climate data from two long-term global datasets, WorldClim V.2.0 and Chelsa V.1.2, in representing variables like precipitation and temperature for the urabá region of Colombia. additionally, climate variables from these datasets have been used to estimate evapotranspiration using traditional methods such as the Turc, hargreaves and Thornthwaite equations. finally, the results of long-term spatial climate characterization are used to apply the water balance equation in the surface at the watershed scale, to obtain the long-term average streamflow of the main streams of the urabá region; these streamflows are compared with the observations of hydrological stations. We find that the WorldClim and Chelsa rainfall estimates show average differences between 20% and 23% compared to the average annual rainfall in the area from in situ measurements. both datasets are able to reproduce the rainfall average annual cycle, although Chelsa shows a slightly better performance. regarding near surface air temperature we find that WorldClim shows a good performance, while Chelsa significantly underestimates the average temperature. finally, we found that the hargreaves and Thornthwaite methods lead to the best performance in estimating streamflow from the water balance, probably because details of the seasonal behavior of variables like temperature and radiation are explicitly included in these methods. On the other hand, the Turc method yields larger estimates of evapotranspiration and therefore the corresponding derived streamflows are lower than those observed. The good performance of the WorldClim and Chelsa datasets in representing variables like precipitation, temperature, and the derived watershed-scale streamflow, suggest that these long-term global climate datasets can be used to study the spatial distribution of important hydrological variables in the urabá region of Colombia, and consequently the estimation of average streamflows through the method of the long-term water balance.

Si bien existen muchas alusiones en cuanto a los efectos del cambio climático en el ciclo hidrológico global, éstas se encuentran referidas generalmente a la temperatura atmosférica, la precipitación y al incremento del nivel del mar, y poco se habla de los efectos sobre el recurso hídrico subterráneo. A partir de un ejercicio de revisión bibliográfica que incluyó alrededor de 60 referencias de los últimos 10 años, se empieza a consolidar un marco de referencia al respecto, y se efectúa una primera aproximación a la evaluación de los efectos del cambio climático sobre tres sistemas hidrogeológicos en Colombia. Considerando los escenarios de cambio climático propuestos por el IDEAM, se practica un análisis conceptual de las posibles implicaciones sobre la recarga para los acuíferos del Valle de Aburrá, Urabá antioqueño y Cuenca del rio Ranchería, que conllevaría a una disminución de la descarga de aguas subterráneas y un impacto directo en ecosistemas dependientes.

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<p>Despite a significant increase in attention for uptake of scientific results, the integration of emerging science in policy development and implementation remains challenging. The persistent gap between science and policy may frustrate the parties involved. For the scientists, the intended impacts of what are typically very much applied research efforts remain unattained. Those involved in policy implementation and development may perceive a lack of scientific support. This may particularly be the case in transitional countries, where the development of science may struggle to keep up with rapid societal and policy development; with several factors either impeding or facilitating the uptake of emergent scientific knowledge.</p><p>We implemented a series of participatory and action research activities to support the development and implementation of groundwater management policies in Colombia and explore barriers and enabling conditions to a functional science-policy interface. The factors that either impede or facilitate the process are examined through three case studies in different regions of the country. Although the national policies that govern groundwater resources management in these three areas are the same; the degree to which scientific knowledge is used to support policy implementation varies. Several factors are identified that influence the effectivity of the linkage, including among others; the availability of scientific knowledge; the establishing of trust relationships and positioning of institutions and stakeholders; as well as institutional readiness in supporting the policy implementation process. This comparison provides useful insight into how addressing some of the impeding factors may enrich the science-policy process.</p>

Understanding the physical, chemical and biological system is an indispensable precondition to addressing groundwater management. This understanding is based on Conceptual Hydrogeological Models, which contain different interpretations and their validity is checked through the application of specific research techniques (numerical modelling, hydrochemistry, isotope hydrology,process evaluation and biological functions). This paper describes the experience carried out by an academic team that, together with entities responsible for the protection of waterresources, established strategic alliances to improve the knowledge of the hydrogeological system,providing new elements for governance. This study was carried out in the Urabá antioqueño zone, located north-west of Colombia. A complex aquifer system is located in the region,characterized by a series of permeable, semi-permeable and impermeable layers. In such alayered aquifer the determination of the physical, chemical and biological characteristics of the layers and their management are a challenge for researchers because groundwater represents a strategic resource for supplying the population and developing economic activities. Starting from the conceptual hydrogeological model, multiscale numerical modelling exercises have been carried out, enabling the characterization of local, intermediate and regional flow systems. In addition,by determining the natural background level, the concentration ranges of chemical compounds from natural sources were obtained, in order to detect future changes in water quality. It was also possible to examine the stygofauna, which allowed the recognition of different types of organisms (stygobits, stygophiles and stygoxens) associated with underground ecosystems.These scientific elements serve as a support for the management instruments such as the groundwater management plan that is important for water governance, ensuring its future sustainability.