Mikołaj Piniewski

Multi-Site Calibration and Validation of the Hydrological Component of SWAT in a Large Lowland Catchment

This study describes an application of a hydrological component of the catchment model, Soil and Water Assessment Tool (SWAT) in the Narew basin (ca. 28,000 km2) situated in the north-east of Poland. The main objective was to perform a multi-site (spatially distributed) calibration and validation of SWAT using daily observed flows from 23 gauging stations as well as to assess the model’s capability to perform reliable simulations at spatial scales that were smaller than those in the calibration phase. A detailed description of the model configuration for the Narew basin upstream from Zambski Kościelne gauge has been given. Building a SWAT project for a large-scale application appeared to be a demanding task, with the most critical part of preparing soil input data. Sensitivity analysis performed using a LH-OAT method indicated which parameters should be used in autocalibration. The ParaSol tool allowed to find the best parameter values from 8D parameter space in 11 calibration areas. The calibrated model generally performed well, with average Nash–Sutcliffe Efficiency for daily data equal to 0.68 for calibration period and 0.57 for validation period. SWAT correctly conserved the mass balance in different parts of the catchment as well as at the main outlet. The model results were significantly better in large basins than in small basins. Spatial validation performed at 12 independent catchments ranging in size from 355 to 1,657 km2 revealed that adapted SWAT model should rather not be used in the Narew basin catchments smaller than ca. 600 km2. It is believed that ensuring reliability of SWAT results at smaller spatial scales, which would be of interest to decision-makers, would require providing better input data and in particular using significantly more precipitation stations.

An ensemble analysis of climate change impacts on streamflow seasonality across 11 large river basins

The paper investigates climate change impacts on streamflow seasonality for a set of eleven representative large river basins covering all continents and a wide range of climatic and physiographic settings. Based on an ensemble of nine regional hydrological models driven by climate projections derived from five global circulation models under four representative concentration pathways, we analyzed the median and range of projected changes in seasonal streamflow by the end of the twenty-first century and examined the uncertainty arising from the different members of the modelling chain. Climate change impacts on the timing of seasonal streamflow were found to be small except for two basins. In many basins, we found an acceleration of the existing seasonality pattern, i.e. high-flows are projected to increase and/or low-flows are projected to decrease. In some basins the hydrologic projections indicate opposite directions of change which cancel out in the ensemble median, i.e., no robust conclusions could be drawn. In the majority of the basins, differences in projected streamflow seasonality between the low emission pathway and the high emission pathway are small with the exception of four basins. For these basins our results allow conclusions on the potential benefits (or adverse effects) of avoided GHG emissions for the seasonal streamflow regime.

Hydrological modelling of the Vistula and Odra river basins using SWAT

ABSTRACT This paper presents a large-scale application of the SWAT model for water balance and natural streamflow simulation in the entire basins of the Vistula and the Odra, covering most of the territory of Poland. A tailored calibration approach was designed to achieve satisfactory goodness-of-fit across a range of catchment sizes. Model calibration and evaluation driven by high-resolution climate data showed overall good behaviour for 80 benchmark catchments divided into eight clusters, and spatial evaluation for 30 gauges showed that the designed regionalization scheme performed well (median KGE of 0.76). Basin-averaged estimates of blue and green water flow and green water storage estimated using the calibrated model were 185, 517 and 206 mm, respectively. This study provides a basis for future work, such as assessing climate change impacts on hydrology, assessing flow alterations, and water quality simulation. The model output is publicly available through an online research data archive (doi:10.4121/uuid:b8ab4f5f-f692-4c93-a910-2947aea28f42). EDITOR A. Castellarin ASSOCIATE EDITOR G. Thirel

Changes in low and high flows in the Vistula and the Odra basins: model projections in the European-scale context

A number of extensive droughts and destructive floods have occurred in Poland in the last 25 years, hence projections of low and high river flows are of considerable interest and importance. In the first part of this paper, projections of low and high flows in the rivers of the Vistula and the Odra basins (VOB region), for two future time horizons, are presented. Projections are based on the SWAT hydrological model simulations driven by results of the EURO-CORDEX experiment under Representative Concentration Pathways 4.5 and 8.5. The VOB region covers most of Poland and parts of five neighboring countries, giving this study an international relevance. In the second part of the paper a review of projections of low and high flows in rivers in Central and Eastern Europe is presented. Despite a substantial spread of flow projections, the main message of the modelling part is that increases of both low and high flows are dominating. The magnitude of increase of low flow is considerably higher than that of high flow. In other words, future streamflow droughts are projected to be less severe, while, in contrast, river floods are projected to increase, which is a challenge for flood risk reduction, water management and climate change adaptation. There is an overall agreement of our findings for the VOB region with projections of hydrological extremes from large-scale models forced by EURO-CORDEX results in the European-scale studies.

Environmental water quantity projections under market-driven and sustainability-driven future scenarios in the Narew basin, Poland

Abstract The aim of this article is to assess the impact of four scenarios combining possible changes in climate, atmospheric carbon dioxide, land use and water use by 2050, on the specific set of ecologically relevant flow regime indicators that define environmental flow requirements in a semi-natural river basin in Poland. This aim is presented through a modelling case study using the Soil and Water Assessment Tool (SWAT). Indicators show both positive and negative responses to future changes. Warm projections from the IPSL-CM4 global climate model combined with sustainable land- and water-use projections (SuE) produce the most negative changes, while warm and wet projections from the MIROC3.2 model combined with market-driven projections (EcF) gave the most positive changes. Climate change overshadows land- and water-use change in terms of the magnitude of projected flow alterations. The future of environmental water quantity is brighter under the market-driven rather than the sustainability-driven scenario, which shows that sustainability for terrestrial ecosystems (e.g. more forests and grasslands) can be at variance with sustainability for riverine and riparian ecosystems (requiring sufficient amount and proper timing of river flows). Editor D. Koutsoyiannis Citation Piniewski, M., Okruszko, T., and Acreman, M.C., 2014. Environmental water quantity projections under market-driven and sustainability-driven future scenarios in the Narew basin, Poland. Hydrological Sciences Journal, 59 (3–4), 916–934.

Effect of modelling scale on the assessment of climate change impact on river runoff

Abstract The effect of using two distributed hydrological models with different degrees of spatial aggregation on the assessment of climate change impact on river runoff was investigated. Analyses were conducted in the Narew River basin situated in northeast Poland using a global hydrological model (WaterGAP) and a catchment-scale hydrological model (SWAT). Climate change was represented in both models by projected changes in monthly temperature and precipitation between the period 2040–2069 and the baseline period, resulting from two general circulation models: IPSL-CM4 and MIROC3.2, both coupled with the SRES A2 emissions scenario. The degree of consistency between the global and the catchment model was very high for mean annual runoff, and medium for indicators of high and low runoff. It was observed that SWAT generally suggests changes of larger magnitude than WaterGAP for both climate models, but SWAT and WaterGAP were consistent as regards the direction of change in monthly runoff. The results indicate that a global model can be used in Central and Eastern European lowlands to identify hot-spots where a catchment-scale model should be applied to evaluate, e.g. the effectiveness of management options. Editor D. Koutsoyiannis; Associate editor F.F. Hattermann Citation Piniewski, M., Voss, F., Bärlund, I., Okruszko, T., and Kundzewicz. Z.W., 2013. Effect of modelling scale on the assessment of climate change impact on river runoff. Hydrological Sciences Journal, 58 (4), 737–754.

CHASE-PL Climate Projection dataset over Poland – bias adjustment of EURO-CORDEX simulations

The paper provides an update of climate projections over Poland by adopting the new generation of concentration pathways and recent developments in climate modelling.It provides a dataset of scenarios of temperature and precipitation developed for nine individual RCM simulations and the ensamble one. For each RCM the bias is firstly assessed and than the scenario is adjusted. The scenarios are prepared on annual and seasonal resolution.

Responses of fish and invertebrates to floods and droughts in Europe

Floods and droughts, two opposite natural components of streamflow regimes, are known to regulate population size and species diversity. Quantifiable measures of these disturbances and their subsequent ecological responses are needed to synthesize the knowledge on flow–ecosystem relationships. This study for the first time combines the systematic review approach used to collect evidence on the ecological responses to floods and droughts in Europe with the statistical methods used to quantify the extreme events severity. Out of 854 publications identified in literature search, 54 papers were retained after screening and eligibility checks, providing in total 82 case studies with unique extreme event—ecological response associations for which data were extracted. In this way, a database with metadata of case studies that can be explored with respect to various factors was constructed. This study pinpointed the research gaps where little evidence could be synthesized, for example, drought event studies and fish studies. It was demonstrated that in many cases the studied metrics (abundance, density, richness, and diversity) showed statistically significant decreases after or during the event occurrence. The responses in invertebrate density and richness were in general more negative than the corresponding responses in fish. Biota resistance to floods was found to be lower than the resistance to droughts. The severity of extreme events was not found to be an important factor influencing ecological metrics, although this analysis was often hampered by insufficient number of case studies. Conceivably, other factors could mask any existing relationships between disturbance severity and biotic response.

What can we learn from the projections of changes of flow patterns? Results from Polish case studies

River flow projections for two future time horizons and RCP 8.5 scenario, generated by two projects (CHASE-PL and CHIHE) in the Polish-Norwegian Research Programme, were compared. The projects employed different hydrological models over different spatial domains. The semi-distributed, process-based, SWAT model was used in the CHASE-PL project for the entire Vistula and Odra basins area, whilst the lumped, conceptual, HBV model was used in the CHIHE project for eight Polish catchments, for which the comparison study was made. Climate projections in both studies originated from the common EURO-CORDEX dataset, but they were different, e.g. due to different bias correction approaches. Increases in mean annual and seasonal flows were projected in both studies, yet the magnitudes of changes were largely different, in particular for the lowland catchments in the far future. The HBV-based increases were significantly higher in the latter case than the SWAT-based increases in all seasons except winter. Uncertainty in projections is high and creates a problem for practitioners.

Modelling of discharge, nitrate and phosphate loads from the Reda catchment to the Puck Lagoon using SWAT

Abstract Modelling of discharge, nitrate and phosphate loads from the Reda catchment to the Puck Lagoon using SWAT. This study presents an application of the SWAT model (Soil and Water Assessment Tool) in an agricultural, coastal catchment situated in northern Poland, draining an area of 482 km2 (the Reda catchment). The main objective of this study was calibration and validation of the model against daily discharge and water quality parameters (bi-monthly total suspended solids [TSS], nitrate nitrogen [N-NO3] and phosphate phosphorus [P-PO4] loads). Calibration and validation were conducted using the SWAT-CUP program and SUFI-2 (Sequential Uncertainty Fitting Version 2) algorithm. The Nash- -Sutcliffe efficiency, which was set as an objective function in calibration of all variables, was equal for discharge to 0.75 and 0.61 for calibration and validation periods, respectively. For TSS, N-NO3 and P-PO4 loads NSE was equal to 0.56, 0.62 and 0.53 in calibration period, and 0.22, 0.64 and -1.78 in validation period, respectively. For the calibration period all the results are satisfactory or good, while for the validation period the results for TSS and P-PO4 loads are rather poor, which is related mainly to the lack of homogeneity between calibration and validation periods. These results demonstrate that SWAT is an appropriate tool for quantification of nutrient loads in Polish agricultural catchments, in particular for N-NO3. The model can therefore be applied for water resources management, for quantification of scenarios of climate and land use change, and for estimation of the Best Management Practices efficiency