Quantifying the effects of watershed subdivision scale and spatial density of weather inputs on hydrological simulations in a Norwegian Arctic watershed

The effects of watershed subdivisions on hydrological simulations have not been evaluated in Arctic conditions yet. This study applied the Soil and Water Assessment Tool and the threshold drainage area (TDA) technique to evaluate the impacts of watershed subdivision on hydrological simulations at a 5,913-km2 Arctic watershed, Målselv. The watershed was discretized according to four TDA scheme scales including 200, 2,000, 5,000, and 10,000 ha. The impacts of different TDA schemes on hydrological simulations in water balance components, snowmelt runoff, and streamflow were investigated. The study revealed that the complexity of terrain and topographic attributes altered significantly in the coarse discretizations: (1) total stream length (−47.2 to −74.6%); (2) average stream slope (−68 to −83%); and (3) drainage density (−24.2 to −51.5%). The spatial density of weather grid integration reduced from −5 to −33.33% in the coarse schemes. The annual mean potential evapotranspiration, evapotranspiration, and lateral flow slightly decreased, while areal rainfall, surface runoff, and water yield slightly increased with the increases of TDAs. It was concluded that the fine TDAs produced finer and higher ranges of snowmelt runoff volume across the watershed. All TDAs had similar capacities to replicate the observed tendency of monthly mean streamflow hydrograph, except overestimated/underestimated peak flows. Spatial variation of streamflow was well analyzed in the fine schemes with high density of stream networks, while the coarse schemes simplified this. Watershed subdivisions affected model performances, in the way of decreasing the accuracy of monthly streamflow simulation, at 60% of investigated hydro-gauging stations (3/5 stations) and in the upstream. Furthermore, watershed subdivisions strongly affected the calibration process regarding the changes in sensitivity ranking of 18 calibrated model parameters and time it took to calibrate

A Review of Hydrological Models Applied in the Permafrost-Dominated Arctic Region

The Arctic region is the most sensitive region to climate change. Hydrological models are fundamental tools for climate change impact assessment. However, due to the extreme weather conditions, specific hydrological process, and data acquisition challenges in the Arctic, it is crucial to select suitable hydrological model(s) for this region. In this paper, a comprehensive review and comparison of different models is conducted based on recently available studies. The functionality, limitations, and suitability of the potential hydrological models for the Arctic hydrological process are analyzed, including: (1) The surface hydrological models Topoflow, DMHS (deterministic modeling hydrological system), HBV (Hydrologiska Byråns Vattenbalansavdelning), SWAT (soil and water assessment tool), WaSiM (water balance simulation model), ECOMAG (ecological model for applied geophysics), and CRHM (cold regions hydrological model); and (2) the cryo-hydrogeological models ATS (arctic terrestrial simulator), CryoGrid 3, GEOtop, SUTRA-ICE (ice variant of the existing saturated/unsaturated transport model), and PFLOTRAN-ICE (ice variant of the existing massively parallel subsurface flow and reactive transport model). The review finds that Topoflow, HBV, SWAT, ECOMAG, and CRHM are suitable for studying surface hydrology rather than other processes in permafrost environments, whereas DMHS, WaSiM, and the cryo-hydrogeological models have higher capacities for subsurface hydrology, since they take into account the three phase changes of water in the near-surface soil. Of the cryo-hydrogeological models reviewed here, GEOtop, SUTRA-ICE, and PFLOTRAN-ICE are found to be suitable for small-scale catchments, whereas ATS and CryoGrid 3 are potentially suitable for large-scale catchments. Especially, ATS and GEOtop are the first tools that couple surface/subsurface permafrost thermal hydrology. If the accuracy of simulating the active layer dynamics is targeted, DMHS, ATS, GEOtop, and PFLOTRAN-ICE are potential tools compared to the other models. Further, data acquisition is a challenging task for cryo-hydrogeological models due to the complex boundary conditions when compared to the surface hydrological models HBV, SWAT, and CRHM, and the cryo-hydrogeological models are more difficult for non-expert users and more expensive to run compared to other models

Assessment of the impacts of landscape patterns on water quality in Trondheim rivers and Fjord, Norway

Due to the impacts of hydrological and ecological processes on water quality, discharges from upstream catchments have induced significant pollution to the recipients. This study aims to investigate the possible pollution sources from catchments with different types of land use and landscape patterns and develop the relationships between water quality and the catchment hydro-geological and environmental variables. Data from 10 monitoring sites in Trondheim formulated the basis of the case study. Thermotolerant coliform bacteria (TCB) and total phosphorus (TP) were applied as main indicators to represent the water quality in the recipient rivers, streams and in Trondheim Fjord. Based on the GIS-oriented spatial analysis, 15 hydro-geographical and landscape parameters were selected as explanatory variables. Multiple linear regression (MLR) models were developed at catchment and river reach scales to study correlations between the explanatory variables and the response variables, TCB and TP, in rain and snow seasons. The study showed that the spatial landscape patterns resulted in differences in the concentrations of TCB and TP in the recipients. The agricultural land was shown to be the main pollution source, leading to a higher concentration of TP in streams. Buildings, roads, and other impervious areas have induced an increase in both TCB and TP. In contrast, the forest areas, lakes, river density and steep river slopes were shown to have capacity to filter incoming P-rich runoff, thus prevent pollutant conveyance and accumulation in recipients

LLMvsSmall Model? Large Language Model Based Text Augmentation Enhanced Personality Detection Model

Personality detection aims to detect one's personality traits underlying in social media posts. One challenge of this task is the scarcity of ground-truth personality traits which are collected from self-report questionnaires. Most existing methods learn post features directly by fine-tuning the pre-trained language models under the supervision of limited personality labels. This leads to inferior quality of post features and consequently affects the performance. In addition, they treat personality traits as one-hot classification labels, overlooking the semantic information within them. In this paper, we propose a large language model (LLM) based text augmentation enhanced personality detection model, which distills the LLM's knowledge to enhance the small model for personality detection, even when the LLM fails in this task. Specifically, we enable LLM to generate post analyses (augmentations) from the aspects of semantic, sentiment, and linguistic, which are critical for personality detection. By using contrastive learning to pull them together in the embedding space, the post encoder can better capture the psycho-linguistic information within the post representations, thus improving personality detection. Furthermore, we utilize the LLM to enrich the information of personality labels for enhancing the detection performance. Experimental results on the benchmark datasets demonstrate that our model outperforms the state-of-the-art methods on personality detection

International experience on rainwater harvesting and stormwater utilisation – a literature review

Norway is a country with abundant water resources. Rainwater harvesting and stormwater utilization (RWH) has not been a central topic in Norway for a very long time. In recent years, however, we have experienced more frequent extreme storm events and less precipitation over other periods, because of climate change. We therefore need solutions to handle both too much and too little water problems. Rainwater harvesting has been recognised as one of the efficient measures for municipal stormwater management (for example in Oslo) and one of the sustainable nature-based solutions for flood control and drought mitigation and diverse social and environmental benefits. Despite of this awareness, the progress of rainwater harvesting in Norway is not yet much implemented in practices. This paper aims introduces international experience on rainwater harvesting and utilization from several selected countries in Europe and other parts of the world, thus paves the ground for use of the rainwater resources smartly and sustainably, and build Norwegian cities to be more water resilient and water smart.Internasjonal erfaring om høsting og utnyttelse av regnvann og overvann. Norge har store ferskvannsressurser. Av den grunn har regnvannshosting ikke vært et fremtredende tema. Regnvann (overvann) har i byer stort sett blitt behandlet som et problem man kunne lose ved a legge store nok rør og frakte det bort. Virkningene av klimaendringene har vært både okt antall flomhendelser og tørkeperioder. Disse endringene medfører at vi må ha systemer som bade handterer for mye og for lite vann med større svingninger enn vi tidligere har sett. Det har de siste tjue arene i større grad vart satset på lokal handtering av overvann (LOD) og det finnes også eksempler på at man enkelte steder har inkludert regnvannshosting i overvannssystemene (f.eks. i Oslo). Det har også blitt tatt i bruk mer naturbaserte løsninger innen overvannshåndtering. Men, det er ikke nok. I denne artikkelen er det gjort en gjennomgang av erfaringen at man har med regnvannshøsting og utnyttelse av overvann i utvalgte land bade i Europa og andre deler i verden. Disse erfaringene kan tjene som eksempler for regnvannshøsting og bærekraftig overvannshåndteringen i norske byer.publishedVersio

Flooding Analysis of Urban Drainage Systems

<b>- Description of the problems</b> Throughout history floods have been one of the most severe natural catastrophes, which brought about loss of lives and huge economic losses in addition to the influence on community activities and adverse effects on the environment. We have witnessed enormous flood events almost all over the world, even in the early years of 21st century. The cruel lesson learnt is that we have not coped well with floods. Studying the risk of flooding is the goal of this thesis. The focus is given to flooding of urban drainage systems. Urban climate, human activities and land use vary quickly and greatly with time. These variations modify the features of both urban hydrology and hydraulics, and change the distribution of water. It may lead to dual adverse effects in one region: the severe water shortage in one period and the increasing risk of flooding in another period. Therefore, finding appropriate solutions for these problems has been being a great challenge for the whole world. <b>- Aims of this study</b> This study aims to contribute ideal approaches and models to understand deeply urban flooding problems, i.e. to find the causes of flooding, to analyze their propagations and on this basis to evaluate the risk of flooding, and finally to search for solutions for flood mitigation. <b>- Study contents and methodologies</b> Distinguishing the potential hazards of urban flooding, delineating the changes of urban lands, developing models to simulate flooding and examining different measures to mitigate the risk of flooding constitute the main contents of this study. It is carried out by both qualitative analysis and quantitative simulations in a stepwise manner. Regarding the stochastic characteristics of flooding, a risk analysis initiates the study, which aims to formulate flooding scenarios in general urban environment through procedures of system definition, hazard identification, causal analysis, frequency analysis, consequence estimation and mitigation. A Norwegian case study illustrates the whole process. Following the risk analysis, GIS technology is introduced to delineate the variation of topography. GIS hydrological modeling is applied to delineate the basic hydrological elements from a Digital Elevation Model (DEM). The accuracy of grid DEM and the influence of buildings are studied. Two urban flooding models, the "basin" model and the dual drainage model, are developed on the basis of the MOUSE program (DHI, 2000). The three models, i.e. the MOUSE model, the “basin” model and the dual drainage model, are examined through two case studies, and the flow capacities of the existing sewers in these two case studies are then checked. Following the flooding simulation, the effectiveness of four flooding mitigation measures is tested. <b>- Main results</b> Sixty-eight (68) potential flooding hazards are identified by risk analysis in Chapter three. In combination with Trondheim case study, the frequencies of several flooding scenarios are studied, and it is indicated that the flooding of urban drainage systems happens more frequently than river flooding. When it happens, urban flooding disturbs very much the activities in flooding areas. Therefore management attentions should be paid to urban flooding in addition to large river flooding. GIS is used as a bridge between digital data and numerical flooding simulation. Two important hydrological elements, watersheds and surface stream networks, are derived from grid DEM in Chapter four. The preliminary flood risk zones are delineated in combination with two case studies. They provide useful information for flood management. The three flooding models are calibrated through two case studies: Trondheim- Fredlybekken catchment in Norway and Beijing-Baiwanzhuang (BWZ) catchment in China. Flooding checking of the existing sewer systems in these two case studies indicates that the current flow capacities of sewers are less than the designed capacities. Consequently, flood mitigation measures are examined in the following Chapter six. The study indicates that the combination of structural and non-structural flood mitigation measures are regarded as the comprehensive solution for flood control. <b>- Restrictions of the developed models</b> The developed flood models are restricted to summer and autumn flooding situations. In other words, the snowmelt routine is not included in the hydrological model applied. However, if a hydrological model that is able to simulate snowmelt could be connected to the developed models, then the hydraulic analysis would be carried out similarly

Flomrisiko og konsekvensanalyse : Pilotprosjekt E18 ved Hoffsbekken

Rapporten inngår i en serie rapporter fra FoU-prosjektet “Klima og transport”, etatsprosjekt 2007-2010.Rapporten inngår i en serie rapporter fra FoUprosjektet “Klima og transport”, etatsprosjekt 2007-2010. Hensikten med prosjektet er å forbedre rutiner og regelverk for planlegging, prosjektering, bygging, drift og vedlikehold av vegnettet som svar på endrede klimaforhold. Rapporten tilhører delprosjekt 3 ”Flom og erosjonssikring” og inneholder en hydraulisk kapasitetsberegning for en kulvert i Oslo, under E18 ved Hoffsbekken. Effekten av klimaendring og urbanisering er beregnet og kulverten vurderes som flomutsatt. Kulvertens kapasitet er ikke stor nok til en 20 års flom i Hoffsbekken

Flomrisiko og konsekvensanalyse : Pilotprosjekt E18 ved Hoffsbekken

Rapporten inngår i en serie rapporter fra FoUprosjektet “Klima og transport”, etatsprosjekt 2007-2010. Hensikten med prosjektet er å forbedre rutiner og regelverk for planlegging, prosjektering, bygging, drift og vedlikehold av vegnettet som svar på endrede klimaforhold. Rapporten tilhører delprosjekt 3 ”Flom og erosjonssikring” og inneholder en hydraulisk kapasitetsberegning for en kulvert i Oslo, under E18 ved Hoffsbekken. Effekten av klimaendring og urbanisering er beregnet og kulverten vurderes som flomutsatt. Kulvertens kapasitet er ikke stor nok til en 20 års flom i Hoffsbekken

Evaluating the effects of watershed subdivision on hydrological simulation by SWAT model in an Arctic watershed

The hydrological model SWAT is a state-of-the-art tool for environmental and water resources management. Like other semi-distributed models, the whole river basin in the SWAT model is delineated into smaller sub-basins prior to conducting the simulation. Watershed delineation is an importance step since it could potentially influence the modelling results. The present study aimed to conducte an investigation of the effects of watershed delineation schemes on hydrological simulation in an Arctic watershed Målselv, north of Norway. Four delineation schemes were set up with different threshold drainage area (TDA) from fine to coarse including 100 ha, 2,000 ha, 5,000 ha and 10,000 ha. The model was run on monthly time step from 1979-2012. The results showed higher variation of average annual precipitation and runoff especially in the upstream sections of the watershed by the fine TDA schemes compared to the coarse ones. The average monthly precipitation and runoff slightly increased from the finest TDA scheme to the coarsest scheme. All TDA schemes reproduced the observed tendency of the average monthly and annual streamflow although the peak flow was over and under estimated at different hydro-gauging stations. The higher value of estimated streamflow was found at the coarsest scheme

Evaluation of the Climate Forecast System Reanalysis data for hydrological model in the Arctic watershed Målselv

The high-resolution Climate Forecast System Reanalysis (CFSR) data have recently become an alternative input for hydrological models in data-sparse regions. However, the quality of CFSR data for running hydrological models in the Arctic is not well studied yet. This paper aims to compare the quality of CFSR data with ground-based data for hydrological modeling in an Arctic watershed, Målselv. The QSWAT model, a coupling of the hydrological model SWAT (soil and water assessment tool) and the QGIS, was applied in this study. The model ran from 1995 to 2012 with a 3-year warm-up period (1995–1997). Calibration (1998–2007), validation (2008–2012), and uncertainty analyses were performed by the Sequential Uncertainty Fitting Version 2 (SUFI-2) algorithm in the SWAT Calibration Uncertainties Program for each dataset at five hydro-gauging stations within the watershed. The objective function Nash– Sutcliffe coefficient of efficiency for calibration is 0.65–0.82 with CFSR data and 0.55–0.74 with groundbased data, which indicate higher performance of the high-resolution CFSR data than the existing scattered ground-based data. The CFSR weather grid points showed higher variation in precipitation than the ground-based weather stations across the whole watershed. The calculated average annual rainfall by CFSR data for the whole watershed is approximately 24% higher than that by ground-based data, which results in some higher water balance components. The CFSR data also demonstrates its high capacities to replicate the streamflow hydrograph, in terms of timing and magnitude of peak and low flow. Through examination of the uncertainty coefficients P-factors ( 0.7) and R-factors (1.5), this study concludes that CFSR data is a reliable source for running hydrological models in the Arctic watershed Målselv