Hydrological Balance Components Research Articles

Calibration and validation of soil water balance (SWB) model in the Inner Argentinian Pampas

Biophysical simulation models can help to satisfactorily estimate the crop performance for grain production, their stability across years and their impact on components of hydrological balance in diverse areas once those models have been calibrated and validated with field data. The Inner Argentinian Pampas (IAP) region is very susceptible to both frequent flooding and random droughts due to flat landscape, sub-humid to semi-arid climate, coarse- textured soils and shallow water tables. The Soil Water Balance (SWB) model appears to be suitable for the IAP region since it includes most of the necessary requirements for the particular conditions of such an environment. The objectives of this study were: i) to identify the most sensitive crop parameters of the SWB model for a satisfactory estimation of aerial biomass, grain yield and crop evapotranspiration in the IAP region; ii) to parameterise and calibrate the SWB model for simulation of aerial biomass, grain yield and crop evapotranspiration of wheat (Triticum aestivum L.), soybean [Glycine max L. (Merr.)] and maize (Zea mays L.); iii) to validate the SWB model using an independent dataset over a wide area in the IAP region. We used data from 9 field experiments for calibration and from 116 field experiments for validation. The most critical parameters, as indicated by a sensitivity analysis, were biomass-transpiration coefficient (Kb), radiation use efficiency (e), and extinction coefficient (k), suggesting that they should be locally obtained before promoting the use of the SWB model in a given region. The SWB model, after calibration, was able to accurately estimate crop aerial biomass (d = 0.97–0.99, GSD = 9.5–23.9% and RMSE = 786–2,438 kg ha−1), grain yield (d = 0.95–0.96, GSD = 4.5–10.7% and RMSE = 357–637 kg ha−1), crop evapotranspiration (d = 0.97–0.99; GSD = 8.1–16.1%, RMSE = 17–51 mm) and soil water content (d = 0.87–0.96, GSD = 11.2–15.5% and RMSE = 9.6–13.2 mm). The robustness to estimate water balance, aerial biomass and grain yield fluctuations for wheat, soybean, and maize across different soil textures and rainfall variability reflects the potential of SWB model as a valuable tool to face the main challenges of the agricultural systems in our region.

A New Model-Based Approach for the Evaluation of the Net Contribution of the European Union Rural Development Program to the Reduction of Water Abstractions in Agriculture

Agriculture is an essential driving force in water resources management and has a central role in the European Union’s Rural Development Programme (RDP). In this study, the solution developed addresses countries characterised by relatively small farms, vast spatial and temporal variability and severe data scarcity. The proposed model-based approach is directly relevant to the evaluation of agricultural policies affecting water abstraction based on multisource data. The evaluation process utilises an entirely spatially distributed, continuous hydrological model. The model provides a gridded output of the main hydrological balance components, as well as vegetation water deficit and irrigation water requirements, on a daily temporal step on a country scale. It provides information at the farm level and facilitates the estimation of water abstractions in agriculture, taking into consideration all the pertinent information included in the Integrated Administration and Control System database that is maintained by RDPs in Europe. Remote sensing data also are used to validate crop patterns. The obtained results were analysed to estimate the net effect of the RDP to the reduction of water abstractions in agriculture. This work produces valuable information concerning the evaluation of agricultural policies and the assessment of land use, and climate change adaptation and mitigation strategies.

Effects of Human Activities on Hydrological Components in the Yiluo River Basin in Middle Yellow River

Land use and land cover change (LUCC) and water resource utilization behavior and policy (WRUBAP) affect the hydrological cycle in different ways. Their effects on streamflow and hydrological balance components were analyzed in the Yiluo River Basin using the delta method and the Soil and Water Assessment Tool (SWAT). The multivariable (runoff and actual evapotranspiration) calibration and validation method was used to reduce model uncertainty. LUCC impact on hydrological balance components (1976–2015) was evaluated through comparison of simulated paired land use scenarios. WRUBAP impact on runoff was assessed by comparing natural (simulated) and observed runoff. It showed that urban area reduction led to decreased groundwater, but increased surface runoff and increased water area led to increased evaporation. LUCC impact on annual runoff was found limited; for instance, the difference under the paired scenarios was <1 mm. Observed runoff was 34.7–144.1% greater than natural runoff during November–June because of WRUBAP. The effect of WRUBAP on wet season runoff regulation was limited before the completion of the Guxian Reservoir, whereas WRUBAP caused a reduction in natural runoff of 21.6–35.0% during the wet season (July–October) after its completion. The results suggest that WRUBAP has greater influence than LUCC on runoff in the Yiluo River Basin. Based on existing drought mitigation measures, interbasin water transfer measures and deep groundwater exploitation could reduce the potential for drought attributable to predicted future climate extremes. In addition to reservoir regulation, conversion of farmland to forestry in the upstream watershed could also reduce flood risk.

Climate change impacts on water balance in Western Bohemia and options for adaptation

Abstract Several basins in Western Bohemia are regularly confronted with water scarcity problems during dry periods that have far-reaching impacts on stream ecology and the availability of drinking water for users. This paper presents a hydrological balance assessment of catchments in Western Bohemia for present and future conditions together with possible directions for climate change adaptation at the local scale. Assessment of climate change impacts on hydrological balance components using an ensemble of regional climate models revealed an increase in air temperature for all months during the year leading to an increase in evaporation. Along with changes in precipitation distribution during the year (increasing winter precipitation and decreasing summer precipitation), groundwater recharge and groundwater storage in general both decrease. Adaptation measures such as water transfers and the construction of water reservoirs are assessed with respect to the goal of increasing water availability in the Western Bohemia region during dry periods.

Hydrological Impacts of the Changes in Simulated Rainfall Fields on Nakanbe Basin in Burkina Faso

Changes in rainfall regime during the last five decades over the West African Sahel have significantly modified the hydrological regime of many rivers with a significant impact on water resources. In this study, the main hydrological processes on the Nakanbe watershed in Burkina Faso are described with two hydrological models: GR2M (lumped and monthly model) and ORCHIDEE (ORganising Carbon and Hydrology In Dynamic EcosystEms) (distributed and half hourly model). Both models were calibrated on the watershed from observed runoff data at Wayen outlet (area of 22,000 km2) for the 1978–1999 period. The mean annual hydrological balance components on the watershed over this period are composed of about 4% of runoff, 10% of groundwater recharge and 86% of actual evapotranspiration for both models. An assessment of the hydrological impacts of the changes in rainfall regime simulated by five regional climate models shows some discrepancies. The hydrological simulations show that the hydrological impacts on the water balance of the watershed come mainly from the changes in rainfall field with regard to the frequency and the intensity of rain events. Compared to the decrease in frequency, it appears that the decrease in the intensity of rain events is much more prejudicial to runoff and groundwater recharge.

Influence of model structure on base flow estimation using Bilan, frier and HBV-light models / Vplyv štruktúry modelu na stanovenie veľkosti podzemného odtoku využitím modelov bilan, frier a hbv-light. j. hydrol. hydromech., 60, 2012, 4; 29 lit., 7 obr., 1 tab.

Hydrological models are widely used tools to solve a broad range of hydrological issues. Each model has its own structure defining inter-relationships of hydrological balance components, and comparative differences in the models’ inner structure must be taken into account when discrepancies result from the same data. Results of base flow simulation by three different models BILAN, FRIER and HBV-light were compared based on knowledge of the models’ internal structure. It was proven that the courses of modelled parameters are quite similar, but that the respective values differ. The highest base flow values were simulated by the BILAN model, due to the threshold value of the soil moisture storage incorporated within this model’s structure. The lowest values were obtained by HBV-light model. Simulated base flow values were compared with groundwater heads and minimum monthly discharges. This comparison showed that the base flow values in the Nitra catchment at Nedožery profile simulated by BILAN and FRIER models are closer to the reality than those, simulated by HBV-light model.

Comparison of SWAP and FAO Agro-Hydrological Models to Schedule Irrigation of Wine Grapes

AbstractThis paper compares two agro-hydrological models that are used to schedule irrigation of a typical Mediterranean crop. In particular, a comparison between the Food and Agriculture Organization (FAO) model, which uses a black box approach, and the soil-water-atmosphere-plant (SWAP) model, which is based on the numerical analysis of Richards’ equation, are shown for wine grape. The comparison was carried out for the 2005 and 2006 irrigation seasons and focused on hydrological balance components and on soil water contents. Next, the ordinary scheduling parameters were identified so that the performance of the two models, which aimed to evaluate the seasonal water requirements and the irrigation times, could be assessed. In the validation phase, both of the models satisfactorily simulated the soil water content, and comparable values of cumulative evapotranspiration were obtained. With the goal of recognizing the crop water stress condition in the field, the original algorithm of the FAO model was mod...

Climate change impact assessment on various components of the hydrological regime of the Malše River basin

Climate change impacts on water cycle at regional scale have been recently very investigated and dis-cussed issue. This study focuses on changes of not only total runoff but also others water balance compo-nents: soil water content and evapotranspiration, in a monthly step. The climate change was described using outputs of two different global circulations models, ECHAM and HadCM based on two divergent scenarios (optimistic B1 and pessimistic A2) according to the IPCC. The simulation of water cycle was processed in the mesoscale Malse basin (437 km2) in southern Bohemia using distributed physically based hydrological model SWIM. The outputs for the time horizon 2050 were assessed in comparison with mean values from the representative period 1987–1998. The study indicates vulnerability against predicted changes of both temperature and precipitation patterns referred to the selected scenarios. A decrease of total runoff was expected; however, hydrological balance will be different particularly in the monthly pattern within a year. The aim of this article is to describe the impact on various hydrological balance components.