Browsing NTNU Open by Author "Alfredsen, Knut Tore"
Now showing items 1-16 of 16
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By-pass valves in hydropower plants: An ecologically important measure to mitigate stranding in rivers due to emergency turbine flow shutdown
Halleraker, Jo Halvard; Natvik, Eirik Vee; Vaskinn, Kjetil Arne; L´Abée-Lund, Jan Henning; Alfredsen, Knut Tore (Journal article; Peer reviewed, 2023)Hydropeaking operations or accidental shutdown in hydropower (HP) plants lead to rapid reduction in river flows downstream HP outlets and cause severe stranding of biota. Stranding of fish in dewatered riverbeds is a major ... -
Climate-Informed Planning and Design of Urban Water Systems
Kristvik, Erle (Doctoral theses at NTNU;2020:286, Doctoral thesis, 2020)Global warming is expected to cause alterations of the climate with potential impacts on urban water systems. As the knowledge base on climate change expands, and regional climate projections become increasingly available ... -
Comparison of two hydrodynamic models for their rain-on-grid technique to simulate flash floods in steep catchment
Godara, Nitesh; Bruland, Oddbjørn; Alfredsen, Knut Tore (Journal article; Peer reviewed, 2024)In this study, two hydrodynamic models, TELEMAC-2D and HEC-RAS 2D, were compared for their Rain-on-Grid (RoG) technique with a particular focus on runoff generation processes in a small and steep catchment. Curve number ... -
Effect of flow ramping on stranding potential related to river morphology—Developing hydraulic indices for peaking severity
Alfredsen, Knut Tore; Tekle, Mulubirhan Gebretsadik (Peer reviewed; Journal article, 2023)Stranding can be an important negative effect downstream of peaking power plants. Much work is put into computing indices of peaking operation based on flow data from power plant outlets or in reaches downstream of power ... -
Evaluating the stormwater management model for hydrological simulation of infiltration swales in cold climates
Bosco, Camillo; Abdalla, Elhadi Mohsen Hassan; Muthanna, Tone Merete; Alfredsen, Knut Tore; Rasten, Britt; Kjennbakken, Heidi; Sivertsen, Edvard (Journal article; Peer reviewed, 2023)The Stormwater Management Model (SWMM) is a widely used tool for assessing the hydrological performance of infiltration swales. However, validating the accuracy of SWMM simulation against observed data has been challenging, ... -
Exploring sensitivities to hydropeaking in Atlantic salmon parr using individual-based modelling
Hedger, Richard David; Sundt-Hansen, Line Elisabeth Breivik; Juarez-Gomez, Ana; Alfredsen, Knut Tore; Foldvik, Anders (Peer reviewed; Journal article, 2023)Hydropeaking (the release of water pulses at hydropower plants) results in temporaryreductions in river channel water-covered area downstream, which may cause fishmortality through stranding. We used a mechanistic modelling ... -
High-resolution mapping of land use changes in Norwegian hydropower systems
Kenawi, Mahmoud Saber Refaei; Alfredsen, Knut Tore; Stürzer, LS; Sandercock, Brett Kevin; Bakken, Tor Haakon (Peer reviewed; Journal article, 2023)The Transition towards sustainable energy systems requires phasing out fossil fuels. Hydropower is a key source of renewable energy and can contribute to reaching a 100 % low carbon-based energy system. Uncertainty remains ... -
Ice and Ice Forces in Small Steep Rivers
Rødtang, Einar Albert (Doctoral theses at NTNU;2023:431, Doctoral thesis, 2023)English summary Given the right circumstances ice can wreak havoc on riverine infrastructure. Ice runs pushing ice floes against bridge piers is frequently the governing design condition for bridges in cold regions. The ... -
Impacts of slope and length on the hydrological performance of green roof drainage mats
Abdalla, Elhadi Mohsen Hassan; Alfredsen, Knut Tore; Muthanna, Tone Merete (Journal article; Peer reviewed, 2024)This study evaluated the impact of the roof slope and length on the retention and detention performance of the drainage mats of green roofs. Artificial rainfall events were applied to a test bed at two different lengths ... -
Methods to safeguard downstream migration of salmonids past hydropower structures
Szabo-Meszaros, Marcell (Doctoral theses at NTNU;2019:104, Doctoral thesis, 2019)Sustainable development of hydropower production must include measures to reduce the negative consequences of river fragmentations. Migratory Atlantic salmon (Salmo salar, L) is one of the species that can be severely ... -
Modelling Flash Floods Driven by Rain-on-Snow Events Using Rain-on-Grid Technique in the Hydrodynamic Model TELEMAC-2D
Godara, Nitesh; Bruland, Oddbjørn; Alfredsen, Knut Tore (Peer reviewed; Journal article, 2023)Due to the changing climate, flash floods have been increasing recently and are expected to further increase in the future. Flash floods caused by heavy rainfall with snowmelt contribution due to sudden rises in temperature ... -
Modelling Flash Floods Driven by Rain-on-Snow Events Using Rain-on-Grid Technique in the Hydrodynamic Model TELEMAC-2D
Godara, Nitesh; Bruland, Oddbjørn; Alfredsen, Knut Tore (Peer reviewed; Journal article, 2013)Due to the changing climate, flash floods have been increasing recently and are expected to further increase in the future. Flash floods caused by heavy rainfall with snowmelt contribution due to sudden rises in temperature ... -
Practice makes the model: a critical review of stormwater green infrastructure modelling practice
Pons, Vincent Jean-Michel Thierry; Abdalla, Elhadi Mohsen Hassan; Tscheikner-Gratl, Franz; Alfredsen, Knut Tore; Sivertsen, Edvard; Bertrand-Krajewski, Jean-Luc; Muthanna, Tone Merete (Peer reviewed; Journal article, 2023)Green infrastructures (GIs) have in recent decades emerged as sustainable technologies for urban stormwater management, and numerous studies have been conducted to develop and improve hydrological models for GIs. This ... -
Quantitative Flood Risk Assessment in Drammenselva River, Norway
Hailemariam, Seble Fissha; Alfredsen, Knut Tore (Peer reviewed; Journal article, 2023)Floods are frequent natural hazards, triggering significant negative consequences for the economy every year. Their impact is expected to increase in the near future due to socio-economic development and climate change. ... -
Remotely sensed data for bathymetric mapping and ecohydraulics modelling in rivers
Sundt, Håkon (Doctoral theses at NTNU;2022:135, Doctoral thesis, 2022)River management decisions must be based on the best knowledge available. But acquiring information on river conditions and translating it into sufficient mitigation measures can be both time- and resource demanding. Remote ... -
Simulation of flash flood peaks in a small and steep catchment using rain-on-grid technique
Godara, Nitesh; Bruland, Oddbjørn; Alfredsen, Knut Tore (Peer reviewed; Journal article, 2023)The frequency of extreme events is increasing as the consequences of climate change. In steep terrains, flash floods with high-flow velocities induce erosion and sedimentation with potentially disastrous changes of flood ...