TY - GEN A1 - Frimpong, Bernard Fosu A1 - Molkenthin, Frank T1 - Tracking Urban Expansion Using Random Forests for theClassification of Landsat Imagery (1986–2015) and PredictingUrban/Built-Up Areas for 2025: A Study of the KumasiMetropolis, Ghana T2 - Land N2 - Kumasi is a nodal city and functions as the administrative and economic capital of the Ashanti region in Ghana. Rapid urbanization has been experienced inducing the transformation of various Land Use Land Cover (LULC) types into urban/built-up areas in Kumasi. This paper aims at tracking spatio-temporal LULC changes utilizing Landsat imagery from 1986, 2013 and 2015 of Kumasi. The unique contribution of this research is its focus on urban expansion analysis and the utilization of Random Forest (RF) Classifier for satellite image classification. Change detection, urban land modelling and urban expansion in the sub-metropolitan zones, buffers, density decay curve and correlation analysis were methodologies adopted for our study. The classifier yielded better accuracy compared to earlier works in Ghana. The evaluation of LULC changes indicated that urban/built-up areas are continually increasing at the expense of agricultural and forestlands. The urban/built-up areas occupied 4622.49 hectares (ha) (23.78%), 13,447.50 ha (69.18%) and 14,004.60 ha (72.05%) in 1986, 2013 and 2015, respectively of the 19,438 ha area of Kumasi. Projection indicated that urban/built-up areas will occupy 15,490 ha (79.70%) in 2025. The urban expansion was statistically significant. The results revealed the importance of spatial modeling for environmental management and city planning. KW - urban/built-up areas KW - land use land cover KW - Kumasi KW - random forest classifier KW - urban expansion analysis Y1 - 2021 UR - https://www.mdpi.com/2073-445X/10/1/44 U6 - https://doi.org/10.3390/land10010044 SN - 2073-445X VL - 10 IS - 1 SP - 1 EP - 21 ER - TY - GEN A1 - He, Qianwen A1 - Molkenthin, Frank T1 - Improving the integrated hydrological simulation on a data-scarce catchment with multi-objective calibration T2 - Journal of Hydroinformatics N2 - The process-based hydrological model Soil and Water Assessment Tool ensures the simulation's reliability by calibration. Compared to the commonly applied single-objective calibration, multi-objective calibration benefits the spatial parameterization and the simulation of specific processes. However, the requirements of additional observations and the practical procedure are among the reasons to prevent the wider application of the multi-objective calibration. This study proposes to consider three groups of objectives for the calibration: multisite, multi-objective function, and multi-metric. For the study catchment with limited observations like the Yuan River Catchment (YRC) in China, the three groups corresponded to discharge from three hydrometric stations, both Nash–Sutcliffe efficiency (NSE) and inversed NSE for discharge evaluation, and MODIS global terrestrial evapotranspiration product and baseflow filtered from discharge as metrics, respectively. The applicability of two multi-objective calibration approaches, the Euclidean distance and nondominated sorting genetic algorithm II, was analyzed to calibrate the above-mentioned objectives for the YRC. Results show that multi-objective calibration has simultaneously ensured the model's better performance in terms of the spatial parameterization, the magnitude of the output time series, and the water balance components, and it also reduces the parameter and prediction uncertainty. The study thus leads to a generalized, recommended procedure for catchments with data scarcity to perform the multi-objective calibration. KW - multi-objective calibration KW - NSGA-II KW - parameter uncertainty KW - SWAT Y1 - 2021 U6 - https://doi.org/10.2166/hydro.2021.132 SN - 1464-7141 VL - 23 IS - 2 SP - 267 EP - 283 ER - TY - GEN A1 - Trinh, Manh Xuan A1 - Molkenthin, Frank T1 - Flood hazard mapping for data-scarce and ungauged coastal river basins using advanced hydrodynamic models, high temporal-spatial resolution remote sensing precipitation data, and satellite imageries T2 - Natural Hazards N2 - This paper presents an integrated approach to simulate flooding and inundation for small- and medium-sized coastal river basins where measured data are not available or scarce. By coupling the rainfall–runoff model, the one-dimensional and two-dimensional models, and the integration of these with global tide model, satellite precipitation products, and synthetic aperture radar imageries, a comprehensive flood modeling system for Tra Bong river basin selected as a case study was set up and operated. Particularly, in this study, the lumped conceptual model was transformed into the semi-distributed model to increase the parameter sets of donor basins for applying the physical similarity approach. The temporal downscaling technique was applied to disaggregate daily rainfall data using satellite-based precipitation products. To select an appropriate satellite-derived rainfall product, two high temporal-spatial resolution products (0.1 × 0.1 degrees and 1 h) including GSMaP_GNRT6 and CMORPH_CRT were examined at 1-day and 1-h resolutions by comparing with ground-measured rainfall. The CMORPH_CRT product showed better performance in terms of statistical errors such as Correlation Coefficient, Probability of Detection, False Alarm Ratio, and Critical Success Index. Land cover/land use, flood extent, and flood depths derived from Sentinel-1A imageries and a digital elevation model were employed to determine the surface roughness and validate the flood modeling. The results obtained from the modeling system were found to be in good agreement with collected data in terms of NSE (0.3–0.8), RMSE (0.19–0.94), RPE (− 213 to 0.7%), F1 (0.55), and F2 (0.37). Subsequently, various scenarios of flood frequency with 10-, 20-, 50-, and 100-year return periods under the probability analysis of extreme values were developed to create the flood hazard maps for the study area. The flood hazards were then investigated based on the flood intensity classification of depth, duration, and velocity. These hazard maps are significantly important for flood hazard assessments or flood risk assessments. This study demonstrated that applying advanced hydrodynamic models on computing flood inundation and flood hazard analysis in data-scarce and ungauged coastal river basins is completely feasible. This study provides an approach that can be used also for other ungauged river basins to better understand flooding and inundation through flood hazard mapping. Y1 - 2021 UR - https://link.springer.com/article/10.1007/s11069-021-04843-1 U6 - https://doi.org/10.1007/s11069-021-04843-1 SN - 0921-030X SN - 1573-0840 VL - 109 IS - 1 SP - 441 EP - 469 ER - TY - GEN A1 - Gourbesville, Philippe A1 - Gomez Valentin, Manuel A1 - Molkenthin, Frank A1 - Hewett, Caspar A1 - Sinicyn, Grzegorz A1 - Griensven, Ann van ED - Gourbesville, Philippe ED - Caignaert, Guy T1 - HydroEurope—WaterEurope: 20 years of Practice in Collaborative Engineering for Hydroinformatics T2 - Advances in Hydroinformatics : Models for Complex and Global Water Issues—Practices and Expectations Springer Water N2 - Since 2000 and under the various Erasmus and Erasmus + frameworks of the European Commission, 6 European universities have initiated an ve innovatiintensive training program dedicated to hydroinformatics and supported by the data of the Var catchment, France. Over the two decades, the HydroEurope/WaterEurope course has welcome more than 2000 M.Sc students with the ambition to equip them with the competences and skills related to hydrological analyst, flood modeling, damage assessment and engineering design with the most advanced simulation tools. The concept of collaborative engineering associated to a project based pedagogic approach has been used to develop teamwork distributed over time—almost 3 months—and space with team members located in the different European participating institutions. The activities are built around the Var catchment that is regularly affected by Mediterranean flood events associated to major damages. The various teams have to elaborate within a holistic approach, mitigation actions. Since the origins, the program has been integrated within the master degree curriculum of each participating institution and academic recognition has been achieved through credits (ECTS). Industrial actors from the hydroinformatic field have been associated to the program since the early stage and have provided support with expert staff and simulation tools that are today offered through a modelling platform. The 20 years of development have underlined the efficiency of the pedagogic approach and have contributed to equip the new generation of water professionals with new concepts and methods for a better water management. Y1 - 2022 UR - https://link.springer.com/chapter/10.1007/978-981-19-1600-7_80 SN - 978-981-19-1600-7 SN - 978-981-19159-9-4 U6 - https://doi.org/10.1007/978-981-19-1600-7_80 SP - 1255 EP - 1280 PB - Springer CY - Singapore ER - TY - GEN A1 - Ramirez, Carlos A1 - Sermet, Yusuf A1 - Molkenthin, Frank A1 - Demir, Ibrahim T1 - HydroLang: An open-source web-based programming framework for hydrological sciences T2 - Environmental Modelling & Software N2 - This paper introduces HydroLang, an open-source and integrated community-driven computational web framework for hydrology and water resources research and education. HydroLang employs client-side web technologies and standards to carry out various routines aimed at acquiring, managing, transforming, analyzing, and visualizing hydrological datasets. HydroLang consists of four major high-cohesion low-coupling modules: (1) retrieving, manipulating, and transforming raw hydrological data, (2) statistical operations, hydrological analysis, and model creation, (3) generating graphical and tabular data representations, and (4) mapping and geospatial data visualization. To demonstrate the framework's capabilities, portability, and interoperability, two detailed case studies (assessment of lumped models and construction of a rainfall disaggregation model) have been presented. HydroLang's unique modular architecture and open-source nature allow it to be easily tailored into any use case and web framework, and it encourages iterative enhancements with community involvement to establish the comprehensive next-generation hydrological software toolkit. Y1 - 2022 UR - https://www.sciencedirect.com/science/article/abs/pii/S1364815222002250?via%3Dihub U6 - https://doi.org/10.1016/j.envsoft.2022.105525 SN - 1364-8152 VL - 157 SP - 1 EP - 13 ER - TY - GEN A1 - Frimpong, Bernard Fosu A1 - Koranteng, Addo A1 - Molkenthin, Frank T1 - Analysis of temperature variability utilising Mann–Kendall and Sen's slope estimator tests in the Accra and Kumasi Metropolises in Ghana T2 - Environmental Systems Research N2 - Temperature variability may have direct and indirect impacts on the environments of the Accra and Kumasi Metropolises in Ghana. This study analysed temperature and trends in temperature in both cities using in-situ measurements from one meteorological station in both cities from 1986 to 2015. The temperature indices were computed using the RClimdex package from the Expert Team on Climate Change Detection Monitoring Indices (ETCCDMI). The temperature time series was pre-whitened before the Mann–Kendall trend and Sen’s slope estimator analysis were applied. Initial analysis revealed minimal variation in temperature in both cities. The results from the analysed temperature indices revealed an increase in warm days and a general rise in the minimum temperature compared to maximum temperatures. Mann Kendall and Sen’s slope revealed significant trends in the annual and seasonal (dry and wet seasons) in minimum temperature in both cities. These might lead to an increased rate of heat-stressed diseases and an overall rise in urban warming in both cities. The analysis of temperature, indices and trends provided comprehensive insights into the temperature of Accra and Kumasi. The results highlight the essence of evaluating temperature indices and trends in light of Climate Change concerns. It is recommended that urban green and blue spaces should be incorporated into land use plans as these policy directions can aid regulate the temperature in both cities. KW - Temperature KW - Urban warming KW - Climate Change Y1 - 2022 UR - https://environmentalsystemsresearch.springeropen.com/articles/10.1186/s40068-022-00269-1 U6 - https://doi.org/10.1186/s40068-022-00269-1 SN - 2193-2697 VL - 11 ER -