Multi-objective calibration of a surface water-groundwater flow model in an irrigated agricultural region: Yaqui Valley, Sonora, Mexico

Multi-objective optimization was used to calibrate a regional surface water-groundwater model of the Yaqui Valley, a 6800 km² irrigated agricultural region located along the Sea of Cortez in Sonora, Mexico. The model simulates three-dimensional groundwater flow coupled to one-dimensional surface water flow in the irrigation canals. It accounts for the spatial distribution of annual recharge from irrigation, subsurface drainage, agricultural pumping, and irrigation canal seepage. The main advantage of the calibration method is that it accounts for both parameter and model structural uncertainty. In this case, results show that the effect of including the process of bare soil evaporation is significantly greater than the effects of parameter uncertainty. Furthermore, by treating the different objectives independently, a better identification of the model parameters is achieved compared to a single-objective approach, since the various objectives are sensitive to different parameters. The simulated water balance shows that 15&ndash;20% of the water that enters the irrigation canals is lost by seepage to groundwater. The main discharge mechanisms in the Valley are crop evapotranspiration (53%), non-agricultural evapotranspiration and bare soil evaporation (19%), surface drainage to the Sea of Cortez (15%), and groundwater pumping (9%). In comparison, groundwater discharge to the estuary was relatively insignificant (less than 1%). The model was further refined by identifying zonal <i>K_v</i> and <i>K_h</i> values based on a spatial analysis of the model residuals

Relative magnitudes of sources of uncertainty in assessing climate change impacts on water supply security for the southern Adelaide water supply system

The sources of uncertainty in projecting the impacts of climate change on runoff are increasingly well recognized; however, translating these uncertainties to urban water security has received less attention in the literature. Furthermore, runoff cannot be used as a surrogate for water supply security when studying the impacts of climate change due to the nonlinear transformations in modeling water supply and the effects of additional uncertainties, such as demand. Consequently, this study presents a scenario-based sensitivity analysis to qualitatively rank the relative contributions of major sources of uncertainty in projecting the impacts of climate change on water supply security through time. This can then be used by water authorities to guide water planning and management decisions. The southern system of Adelaide, South Australia, is used to illustrate the methodology for which water supply system reliability is examined across six greenhouse gas (GHG) emissions scenarios, seven general circulation models, six demand projections, and 1000 stochastic rainfall time series. Results indicate the order of the relative contributions of uncertainty changes through time; however, demand is always the greatest source of uncertainty and GHG emissions scenarios the least. In general, reliability decreases over the planning horizon, illustrating the need for additional water sources or demand mitigation, while increasing uncertainty with time suggests flexible management is required to ensure future supply security with minimum regret.F.L. Paton, H.R. Maier and G.C. Dand

Effects of dietary Na+ deprivation on epithelial Na+ channel (ENaC), BDNF, and TrkB mRNA expression in the rat tongue

<p>Abstract</p> <p>Background</p> <p>In rodents, dietary Na⁺deprivation reduces gustatory responses of primary taste fibers and central taste neurons to lingual Na⁺stimulation. However, in the rat taste bud cells Na⁺deprivation increases the number of amiloride sensitive epithelial Na⁺channels (ENaC), which are considered as the "receptor" of the Na⁺component of salt taste. To explore the mechanisms, the expression of the three ENaC subunits (α, β and γ) in taste buds were observed from rats fed with diets containing either 0.03% (Na⁺deprivation) or 1% (control) NaCl for 15 days, by using <it>in situ </it>hybridization and real-time quantitative RT-PCR (qRT-PCR). Since BDNF/TrkB signaling is involved in the neural innervation of taste buds, the effects of Na⁺deprivation on BDNF and its receptor TrkB expression in the rat taste buds were also examined.</p> <p>Results</p> <p><it>In situ </it>hybridization analysis showed that all three ENaC subunit mRNAs were found in the rat fungiform taste buds and lingual epithelia, but in the vallate and foliate taste buds, only α ENaC mRNA was easily detected, while β and γ ENaC mRNAs were much less than those in the fungiform taste buds. Between control and low Na⁺fed animals, the numbers of taste bud cells expressing α, β and γ ENaC subunits were not significantly different in the fungiform, vallate and foliate taste buds, respectively. Similarly, qRT-PCR also indicated that Na⁺deprivation had no effect on any ENaC subunit expression in the three types of taste buds. However, Na⁺deprivation reduced BDNF mRNA expression by 50% in the fungiform taste buds, but not in the vallate and foliate taste buds. The expression of TrkB was not different between control and Na⁺deprived rats, irrespective of the taste papillae type.</p> <p>Conclusion</p> <p>The findings demonstrate that dietary Na⁺deprivation does not change ENaC mRNA expression in rat taste buds, but reduces BDNF mRNA expression in the fungiform taste buds. Given the roles of BDNF in survival of cells and target innervation, our results suggest that dietary Na⁺deprivation might lead to a loss of gustatory innervation in the mouse fungiform taste buds.</p

A Multiproxy Database of Western North American Holocene Paleoclimate Records

Holocene climate reconstructions are useful for understanding the diverse features and spatial heterogeneity of past and future climate change. Here we present a database of western North American Holocene paleoclimate records. The database gathers paleoclimate time series from 184 terrestrial and marine sites, including 381 individual proxy records. The records span at least 4000 of the last 12 000 years (median duration of 10 725 years) and have been screened for resolution, chronologic control, and climate sensitivity. Records were included that reflect temperature, hydroclimate, or circulation features. The database is shared in the machine readable Linked Paleo Data (LiPD) format and includes geochronologic data for generating site-level time-uncertain ensembles. This publicly accessible and curated collection of proxy paleoclimate records will have wide research applications, including, for example, investigations of the primary features of ocean-atmospheric circulation along the eastern margin of the North Pacific and the latitudinal response of climate to orbital changes. The database is available for download at https://doi.org/10.6084/m9.figshare.12863843.v1 (Routson and McKay, 2020)

Modelling the potential impacts of climate change on the hydrology of the Aipe river basin in Huila, Colombia

[EN] The dynamics of a global world, and humans performing as a new geological force, require that an effort is undertaken to make robust decisions in order to devise strategies for the management and adaptation to climate change. This study aims to investigate the potential impact of climate change on the hydrology of the Aipe river basin in Huila, Colombia. The abcd Thomas model (four parameters) was calibrated and validated for the stream flows of the Aipe catchment (1992¿2012). The sensitivity and identifiability of the parameters were evaluated using the Monte Carlo Analysis Toolbox (MCAT). The results show the ability of the model to simulate the monthly stream flow (Nash¿Sutcliffe efficiency coefficient of 0,89). The most influential parameters are: a (water storage in the soil) and c (contribution to the aquifer). From the simulated scenarios, the baseline (1992¿2012) was estimated to be an average flow of 15,44 m3s¿1; the trend extrapolation scenario estimated a rate 13,79 m3s¿1 (¿10,64%); while for the multi-model assembly scenario it was 9,34 m3s¿1 (¿39,47%) and for the A2 scenario it was 5,74 m3s¿1 (¿62,60%). Lastly, we propose a set of strategies for adaptation to climate change that are committed to the integral management of water resources.[ES] La dinámica de un mundo global y el hombre como nueva fuerza geológica plantean la necesidad de tomar decisiones robustas, diseñar estrategias de manejo y de adaptarse al cambio climático. Este estudio investiga la respuesta hidrológica de la cuenca hidrográfica del río Aipe (688.9 km2 ), en Huila, Colombia, en acorde con los escenarios de cambio climático desde 2011 a 2040. El modelo hidrológico abcd de Thomas (4 parámetros) fue calibrado y validado comparando el caudal simulado y lo observado en el punto de cierre de la cuenca (en la estación Puente Carretera), usando series históricas mensuales (1992¿2012). Realizamos la evaluación de la sensibilidad e identificabilidad de los parámetros con la herramienta `Monte Carlo Analysis Toolbox¿ (MCAT). Los resultados muestran que el modelo es capaz de representar adecuadamente los caudales mensuales observados en el punto de desagüe de la cuenca, al encontrarse un índice de eficiencia de Nash¿Sutcliffe (NSE) de 0,89. Los parámetros más influyentes son a (almacenamiento del agua en el suelo) y c (aporte al acuífero). Con respecto a la simulación de los escenarios, la línea base (1992¿2012) estimó un caudal medio de 15,44 m3 s ¿1 ; el escenario de extrapolación de tendencias estimó un caudal de 13,79 m3 s ¿1 (¿10,64%); el escenario de ensamble multi-modelo de 9,34 m3 s ¿1 (¿39,47%) y el escenario A2 de 5,74 m3 s ¿1 (¿62,60%). Proponemos una batería de medidas de adaptación al cambio climático que buscan la gestión integral del recurso hídrico.Romero-Cuellar, J.; Buitrago-Vargas, A.; Quintero-Ruiz, T.; Francés, F. (2018). Simulación hidrológica de los impactos potenciales del cambio climático en la cuenca hidrográfica del río Aipe, en Huila, Colombia. RIBAGUA - Revista Iberoamericana del Agua. 5(1):63-78. https://doi.org/10.1080/23863781.2018.1454574S63785

Multi-objective calibration of a surface water-groundwater flow model in an irrigated agricultural region: Yaqui Valley, Sonora, Mexico

International audienceMulti-objective optimization was used to calibrate a regional surface water-groundwater model of the Yaqui Valley, a 6800 km2 irrigated agricultural region located along the Sea of Cortez in Sonora, Mexico. The main advantage of the method is that it accounts for both parameter and model structural uncertainty. In this case, results show that the effect of including the process of bare soil evaporation is significantly greater than the effects of parameter uncertainty. Furthermore, by treating the different objectives independently, a better identification of the model parameters is achieved compared to a single-objective approach, since the various objectives are sensitive to different parameters. The simulated water balance shows that 15?20% of the water that enters the irrigation canals is lost by seepage to groundwater. The main discharge mechanisms in the Valley are crop evapotranspiration (53%), non-agricultural evapotranspiration and bare soil evaporation (19%), surface drainage to the Sea of Cortez (15%), and groundwater pumping (9%). In comparison, groundwater discharge to the estuary was relatively insignificant (less than 1%). The model was further refined by identifying zonal Kv and Kh values based on a spatial analysis of the model residuals. This is the first comprehensive flow model of this important surface water-aquifer system, and it will be used in future work to identify optimal groundwater management strategies