Agrohydrological analysis of groundwater recharge and land use changes in the Pampas of Argentina
Kroes, Joop ; Dam, Jos van; Supit, Iwan ; Abelleyra, Diego de; Verón, Santiago ; Wit, Allard de; Boogaard, Hendrik ; Angelini, Marcos ; Damiano, Francisco ; Groenendijk, Piet ; Wesseling, Jan ; Veldhuizen, Ab - \ 2019
Agricultural Water Management 213 (2019). - ISSN 0378-3774 - p. 843 - 857.
Argentina - Capillary rise - Groundwater recharge - Land use - Pampas - Soybean - SWAP - WOFOST
This paper studies the changes of groundwater, climate and land use in the Pampas of Argentina. These changes offer opportunities and threats. Lowering groundwater without irrigation causes drought and successive crop and yield damage. Rising groundwater may alleviate drought as capillary rise supports root water uptake and crop growth, thus narrowing the difference between potential and actual yields. However, rising groundwater may also limit soil water storage, cause flooding in metropolitan areas and have a negative impact on crop yields. Changing land use from continuous soy bean into crop rotations or natural vegetation may decrease groundwater recharge and thus decrease groundwater levels. In case of crop rotation however, leaching of nutrients like nitrate may increase. We quantified these impacts using integrated dynamic crop growth and soil hydrology modelling. The models were tested at field scale using a local dataset from Argentina. We applied distributed modelling at regional scale to evaluate the impacts on groundwater recharge and crop yields using long term weather data. The experiments showed that threats arise from continuous monotone land use. Opportunities are created when a proper balance is found between supply and demand of soil water using a larger differentiation of land use. Increasing the areas of land use types with higher evapotranspiration, like permanent grassland and trees, will contribute to a more stable hydrologic system with more water storage capacities in the soil system and lower groundwater levels. Modelling tools clearly support the evaluation of the impact of land use and climate change on groundwater levels and crop yields.
Impact of hydraulic and storage properties on river leakage estimates : A numerical groundwater flow model case study from southern Benin
Kpegli, Kodjo Apelete Raoul ; Zee, Sjoerd E.A.T.M. van der; Alassane, Abdoukarim ; Bier, George ; Boukari, Moussa ; Leijnse, Anton ; Louw, Perry G.B. de; Mama, Daouda - \ 2018
Journal of Hydrology: Regional Studies 19 (2018). - ISSN 2214-5818 - p. 136 - 163.
Benin - Discharge loss - Flow modelling - Groundwater recharge - Ouémé - River leakage
Study area: The coastal sedimentary basin including the Zou and Ouémé rivers in Benin. Study focus: River discharge loss is known to occur on the Zou and Ouémé rivers in southern Benin since a couple of decades ago. The reason behind this discharge reduction remained so far unclear. In this study, we focus on creating a 3D-numerical model of the system and on evaluating the sensitivity of leakage between the rivers and aquifers to various parameters. New hydrological insights for the region: Results show that leakages along the Zou river and Ouémé stream are tiny (i.e., ∼3% of the discharge losses). This implies that the observed water loss from the Zou and Ouémé rivers is not likely caused by the leakage (infiltration) along these rivers into the subsurface. The streambed conductance is found to be among the factors that impact less the computed leakages in the study area. This study has ranked the different hydraulic and storage properties in their order of importance with respect to the computation of river leakages along the concerned rivers. The determined rank of importance of the hydraulic and storage properties can guide river leakage modelling exercises in similar regions elsewhere.