21 research outputs found

    Long-term Monthly Discharge Prediction for Cimanuk Watershed

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    Although streamflow data is important for water resource planning, it’s long-term availability for Indonesian rivers is limited. One factor could be identified for example lack of observation. Here, we presented observation-based modeling to predict long-term discharge data for Cimanuk watershed in Indonesia. The watershed is categorized as one of the critical watersheds, meanwhile it supports to more than one million people. A well-known hydrological model called Soil and Water Assessment Tools (SWAT) was used to predict monthly discharge. The model was fed with monthly climate data, topography, land use and soil characteristics. We calibrated the model with the observed data from 1974 to 1994 (20 years). Our results showed that the model was a good performance in estimating monthly discharge as indicated by three statistical metrics used. Based on statistical evaluation, the calibration resulted a low percent bias (3.20%), strong correlation (0.73), and high Kling-Gupta Efficiency (0.78). Further, we did a sensitivity analysis for the model, and we found that hydrological response unit was the most influential parameters for the Cimanuk watershed. A long-term discharge data indicated a monsoonal pattern for this watershed

    Evaluation Des Performances Du Modele Agro-Hydrologique SWAT Ă  Reproduire Le Fonctionnement Hydrologique Du Bassin Versant Nakhla (Rif occidental, Maroc)

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    Une compréhension de toutes les composantes du bilan hydrique est indispensable pour raisonner les mesures de gestion rationnelle et durable de la ressource en eau. Malheureusement, plusieurs composantes du bilan hydrique ne sont pas facilement mesurables et le recours à la modélisation est souvent nécessaire. Pour ce faire, le modèle SWAT 2012 (Soil and Water Assessment Tool) a été mis en oeuvre à un pas de temps mensuel et journalier pour évaluer sa capacité à représenter le fonctionnement du bassin versant Nakhla, situé à 20 kilomètres au sud de la ville de Tétouan. Le traitement préalable des données existantes sur le bassin (MNT, pédologie, images satellitaires, données climatiques) a permis de reproduire les caractéristiques naturelles du terrain à une résolution spatiale adaptée aux objectifs de l’étude. La méthodologie adoptée repose sur l’usage du système d’information géographique libre (QGIS) combiné avec le modèle agro-hydrologique SWAT pour effectuer des opérations d’analyse et de modélisation du fonctionnement hydrologique à l’échelle du bassin versant et l’outil SWAT-Cup pour optimiser les opérations d’analyse de sensibilité et d’incertitude. Le processus de calibration est réalisé aux échelles temporelles mensuelle et journalière au niveau de la station Timezouk et au cours de trois périodes : de 1980 à 1983 pour l’initiation, de 1984 à 1987 pour la calibration et de 1988 à 1990 pour la validation. Les résultats obtenus après calage et validation à l’échelle mensuelle montrent une simulation satisfaisante des débits puisque la comparaison des débits mensuels observés et simulés pour la période de calibration a abouti à un NSE de 0,83 et un R2 de 0,88 au niveau de la station Timezouk. Les résultats à l’échelle journalière ne sont pas satisfaisant (NSE< 0.5), ce qui montre que la représentation de la dynamique haute-fréquence des flux d’eau doit encore être améliorée. A comprehension of all the components of water balance is essential for rational and durable management of the water resource. However, the direct assessment of several components of the water balance is very difficult and the use of modeling is often necessary. SWAT 2012 (Soil and Water Assessment Tool) model was thus implemented on a monthly and daily time steps to assess his ability to reproduce the hydrological functioning for the Nakhla watershed, which is located at 20 kilometers in the south of the city of Tetouan. Treatment of environmental data (MNT, pedology, satellite imagery and climatic data) allowed to describing the natural characteristic of the field at a resolution adapted to the objectives of the study. Adopted methodology consisted in the combined use of the SWAT agro hydrological model implemented in the QGIS geographical information system open source for operations of analysis and modeling of hydrological processes at the level of the watershed area and of SWAT-CUP tool to optimize the operations of sensitivity and uncertainty analysis. The calibration process was performed on two temporal scales; monthly and daily; and on the stations Timezouk; and over three periods: warm-up period from 1980 to 1983, calibration period from 1984 to 1987, and the validation period from 1988 to 1990. The results acquired after calibration and validation at monthly time step were satisfactory and presented good level of realism in the simulation of the discharge. The comparison of the monthly observed and simulated discharges for the period of calibration gave a NSE of 0.83 and R2 of 0.88 at the Timezouk station. Nevertheless, daily results are not satisfactory (NSE< 0.5), thus further improvements are required to better simulate the processes at a finer time step

    Integrated hydrologic modeling as a key for sustainable development planning of urban water resources in the semi-arid watersheds of the Gaza Strip

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    This study demonstrates the strength of using integrated hydrologic modeling in a sustainable urban water planning process. It provides a complete view of the urban water system of the Gaza Strip, quantifies the urban water budget interaction with sufficient spatial and temporal details, and supports realistic scenarios inferred from the decision-making agenda. This study comprises three main parts. The first part aims to quantify the impact of urban area expansion on groundwater recharge and surface runoff by developing surface water modeling and investigating the response of watersheds to urban development. The second part provides a spatial-temporal assessment of potential impacts of urban area expansion on groundwater level concerning the link between surface and groundwater models. The third part promotes an integrated hydrologic modeling as a key for sustainable urban water resources considering the coupling of surface water, groundwater flow, and solute transport models. In the first part, a new spatial evaluation for assessing the impact of urbanization was applied for the semi-arid watersheds intersecting with the Gaza coastal aquifer. The SWAT model was calibrated and validated in a semi-automated approach for stream flow in the main watersheds. The results show that the model could simulate water budget components adequately within the complex semi-arid watersheds. Linear relationships between the change in urban area and the corresponding change in surface runoff or percolation were concluded for the urbanized subbasins. The urban-surface runoff index (USI) and the urban-percolation index (UPI) were developed to represent a micro-level evaluation of different urban change scenarios in the subbasins. The global urban-surface runoff index (GUSI) and the global urban-percolation index (GUPI) were derived as macro-level factors reflecting the influence on the overall Gaza coastal aquifer due to urban area expansion. In the second part, a 3-D groundwater flow model was developed using MODFLOW-USG to investigate the groundwater levels within the Gaza coastal aquifer. Recharge estimation is based on a comprehensive approach including the connection to the surface water model (SWAT) for determining percolation from rainfall as well as detailed approaches regarding further recharge components. An unstructured grid (Voronoi cells) generated by MODFLOW-USG engine was used to reduce run time within complicated aquifer boundary conditions. The results indicate a very good fit between measured and simulated heads. Long-term forecasting (2004–2030) of the groundwater levels was carried out as an essential step to support realistic and sustainable water resources planning and decision making. The increasing built-up area was linked to the potential impacts of urban expansion relating to water supply quantities and groundwater recharge components. The percolation was reduced temporally and spatially in the forecasting period based on the projected built-up area as well as the urban-percolation index. Considering the current management situation, the annual groundwater level correlated negatively with the increasing built-up area; the regression line slope was -0.056 m/km2 for the average groundwater levels while it became steeper at -0.23 m/km2 in sensitive locations in the southern part of the Gaza Strip. The groundwater-level trend index was developed as a spatial indicator for the appropriate management alternatives that can achieve less negative trend index. In the last part of this study, a coupling of surface water (SWAT), groundwater (MODFLOW) and solute transport (MT3DMS) models was performed to quantify surface-groundwater and quantity-quality interactions under urban area expansion. The results indicate a good fit between measured and simulated nitrate and chloride concentrations. The response of groundwater level, nitrate concentrations (related to human activities) and chloride concentrations (related to seawater intrusion) to urban area expansion and corresponding changes in the urban water budget were examined on a macro-scale level (the Gaza coastal aquifer domain). The potentials of non-conventional water resources scenarios, namely desalination, stormwater harvesting and treated wastewater reuse as well as an infrastructure performance scenario were investigated. In a novel analysis, groundwater improvement and deterioration under each scenario were defined and discussed in spatial-temporal and statistical approaches. The quality deterioration cycle index was estimated as the ratio between the amounts of low and high quality recharge components within the Gaza Strip boundary predicted for year 2030. The improvement index for groundwater level (IIL) and the improvement index for groundwater quality (IIQ) were developed for the scenarios as measures of the effectiveness toward sustainable groundwater planning

    Hydrological impacts of climate change on rice cultivated riparian wetlands in the Upper Meghna River Basin (Bangladesh and India)

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    Riparian depressional wetlands (haors) in the Upper Meghna River Basin of Bangladesh are invaluable agricultural resources. They are completely flooded between June and November and planted with Boro rice when floodwater recedes in December. However, early harvest period (April/May) floods frequently damage ripening rice. A calibrated/validated Soil and Water Assessment Tool for riparian wetland (SWATrw) model is perturbed with bias free (using an improved quantile mapping approach) climate projections from 17 general circulation models (GCMs) for the period 2031–2050. Projected mean annual rainfall increases (200–500 mm or 7–10%). However, during the harvest period lower rainfall (21–75%) and higher evapotranspiration (1–8%) reduces river discharge (5–18%) and wetland inundation (inundation fraction declines of 0.005–0.14). Flooding risk for Boro rice consequently declines (rationalized flood risk reductions of 0.02–0.12). However, the loss of cultivable land (15.3%) to increases in permanent haor inundation represents a major threat to regional food security

    Runoff simulation using the SWAT model for flood frequency analysis and design flood estimations in the Luvuvhu River catchment, South Africa.

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    Master of Science in Agrometeorology. University of KwaZulu-Natal, Pietermaritzburg, 2018.Abstract available in PDF file

    Wadi Flash Floods

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    This open access book brings together research studies, developments, and application-related flash flood topics on wadi systems in arid regions. The major merit of this comprehensive book is its focus on research and technical papers as well as case study applications in different regions worldwide that cover many topics and answer several scientific questions. The book chapters comprehensively and significantly highlight different scientific research disciplines related to wadi flash floods, including climatology, hydrological models, new monitoring techniques, remote sensing techniques, field investigations, international collaboration projects, risk assessment and mitigation, sedimentation and sediment transport, and groundwater quality and quantity assessment and management. In this book, the contributing authors (engineers, researchers, and professionals) introduce their recent scientific findings to develop suitable, applicable, and innovative tools for forecasting, mitigation, and water management as well as society development under seven main research themes as follows: Part 1. Wadi Flash Flood Challenges and Strategies Part 2. Hydrometeorology and Climate Changes Part 3. Rainfall–Runoff Modeling and Approaches Part 4. Disaster Risk Reduction and Mitigation Part 5. Reservoir Sedimentation and Sediment Yield Part 6. Groundwater Management Part 7. Application and Case Studies The book includes selected high-quality papers from five series of the International Symposium on Flash Floods in Wadi Systems (ISFF) that were held in 2015, 2016, 2017, 2018, and 2020 in Japan, Egypt, Oman, Morocco, and Japan, respectively. These collections of chapters could provide valuable guidance and scientific content not only for academics, researchers, and students but also for decision-makers in the MENA region and worldwide

    Catchment hydrological modelling using ArcSWAT : a study of the Ingula pumped storage scheme (IPSS) catchments, South Africa.

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    Master of Science in Geological Science. University of KwaZulu-Natal, Westville 2017.Abstract available in PDF file
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