Impact of urban geology on model simulations of shallow groundwater levels and flow paths

This study examines the impact of urban geology and spatial discretization on the simulation of shallow groundwater levels and flow paths at the city scale. The study uses an integrated hydrological model based on the MIKE SHE code that couples surface water and 3D groundwater simulations with a leaky sewer system. The effect of the geological configuration was analyzed by applying three geological models to an otherwise identical hydrological model. The effect of spatial discretization was examined by using two different horizontal discretizations for the hydrological models of 50 and 10 m, respectively. The impact of the geological configuration and spatial discretization was analyzed based on model calibration, simulations of high water levels, and particle tracking. The results show that a representation of the subsurface infrastructure, and near-terrain soil types, in the geological model impacts the simulation of the high water levels when the hydrological model is simulated in a 10 m discretization. This was detectable even though the difference between the geological models only occurs in 7 % of the volume of the geological models. When the hydrological model was run in a 50 m horizontal discretization, the impact of the urban geology on the high water levels was smoothed out. Results from particle tracking show that representing the subsurface infrastructure in the hydrological model changed the particles' flow paths and travel time to sinks in both the 50 and 10 m horizontal discretization of the hydrological model. It caused less recharge to deeper aquifers and increased the percentage of particles flowing to saturated-zone drains and leaky sewer pipes. In conclusion, the results indicate that even though the subsurface infrastructure and fill material only occupy a small fraction of the shallow geology, it affects the simulation of local water levels and substantially alters the flow paths. The comparison of the spatial discretization demonstrates that, to simulate this effect, the spatial discretization needs to be of a scale that represents the local variability in the shallow urban geology.</p

Addressing food and nutrition insecurity in the Caribbean through domestic smallholder farming system innovation

Structural conditions underlying the development of CARICOM’s two-tiered agricultural innovation system depict diverse drivers of change over time, versus institutional inertia of export-oriented formal institutions and the neglect of informal domestic markets. Key principles of taking an agroecological approach would include: supporting diversity and redundancy, building connectivity, managing slow variables and feedbacks, improving understanding of socioecological systems as complex adaptive systems, and encouraging polycentric governance systems. In this paper, we review the conditions that have been undermining sustainable food and nutrition security in the Caribbean, focusing on issues of history, economy, and innovation

Prognostic value of clinical signs and blood parameters in equids suffering from hepatic diseases

peer reviewedThe purpose of this retrospective study was to further identify in the equine species the clinical signs and blood parameters that could be useful to identify a hepatic disease and act as predictors of the outcome in animals suffering from an acute hepatic insufficiency. The study included 31 equids that were hospitalized at the University of Liege and that suffered from a hepatic (group 1, 17 cases of hepatitis; group 2, 11 cases of hyperlipemia) or post-hepatic (group 3, 3 cases of cholelithiasis) disease. Frequency of the clinical signs and values of selected blood parameters on admission were compared statistically between surviving and non-surviving animals. The most frequently presented clinical signs were depression, decreased appetite or anorexia, fever, tachycardia, polypnea, icterus, and congested mucous membranes. Frequency of the clinical signs and blood parameter values were not statistically different in surviving and non-surviving animals, with the exception of gamma-glutamyl transferase (GGT) and alkaline phosphatase (ALP), which were significantly higher in animals with fatal outcome, with a cutoff value of 224 and 820 IU/L, respectively