Wyniki wyszukiwania - BazTech

1

Hydrological Modelling in the Ouergha Watershed by Soil and Water Analysis Tool

Erraioui Lamia, Taia Soufiane, Taj-Eddine Kamal, Chao Jamal, El Mansouri Bouabid

Journal of Ecological Engineering

|

2023

|

Vol. 24, nr 4

343--356

EN

Streamflow modelling is crucial for developing successful long-term management, soil conservation planning, and water resource management strategies. The current work attempts to develop a robust hydrological model that simulates streamflow with the slightest uncertainty in the calibration parameters. A physical-based and semidistributed hydrological SWAT model was employed to assess the hydrological simulation of the Ouergha watershed. The monthly simulation of the SWAT model achieved in the time frame from 1990 to 2013 has been split into warm-up (1990–1996), calibration (1997–2005), and validation (2006-2013). The SUFI-2 algorithm’s preliminary sensitivity and uncertainty analysis was done to calibrate the model using 11 hydrologic parameters. The model’s performance and robustness findings are promising. To evaluate the model, the coefficient of determination (R2), Nash-Sutcliffe efficiency (NSE), and percent of bias (PBIAS) were utilized. The value of R2, NSE, and PBIAS ranged from 0.45–0.77, 0.6–0.89, and +12.72 to +21.89% during calibration and 0.51–0.85, 0.64–0.88, and +8.82 to +22.19% during validation period, respectively. A high correlation between the observed and simulated streamflow was recorded during the calibration and validation periods. More than 68% of the observation data are encompassed by the 95PPU across both the calibration and validation intervals, which is excellent in terms of the P-factor and R-factor uncertainty criterion. The projected streamflow matches the observed data well graphically. According to the total hydrological water balance study, 29% of precipitation is delivered to streamflow as runoff, whereas 54% of precipitation is lost through evapotranspiration. The recharge to the deep aquifers is 8%, whereas the lateral flow is 10%. The findings of this study will help as a roadmap for the anticipated water management activities for the basin since the management and planning of water resources require temporal and spatial information.

2

Modelling Runoff and Sedimentation Yield Using Soil and Water Assessment Tool for Wyra River Basin

Pindi Shyamsunder, Jayakumar K. V.

Ecological Engineering & Environmental Technology

|

2023

|

Vol. 24, iss. 5

84--93

EN

Sediment deposition is a natural process that occurs in all reservoirs, resulting in significant storage loss, which has an adverse effect on the economic development of the local area. It is necessary to take appropriate action to control the sedimentation and prevent loss of the storage capacity of the reservoir. In the present study, runoff and sediment data collected at the Konijerla hydrometric station of Wyra reservoir for the period of 1991 to 2019 are used. Data from 2011 to 2016 is used to calibrate and the data from 2017 to 2019 is used to validate the SWAT model. The Wyra watershed consists of 26 sub-basins and 47 HRUs (Hydrological Response Units). Out of these sub-basins, one of the sub-basins is contributing 18.8% of sedimentation. It was also observed that two other sub-basins, though less in area, generate high sediments. Seasonal sediment analysis showed that sedimentation increased by 12% in the month of August for wet years. Overall sedimentation increased in wet years by 10.60% and in dry years, it decreased by 18.78%. The SWAT model was satisfactory in the calibration and validation periods for various parameters used. Hence, this model can be used for sedimentation study, as well as a planning tool in the reservoir capacity management.

3

Sediment yield modeling in Awash Melkasa dam watershed, upper Awash River basin, Ethiopia

Daba Bayisa Itana, Demissie Tamene Adugna, Tufa Fayera Gudu

Acta Geophysica

|

2023

|

Vol. 71, no. 5

2287--2306

EN

Soil erosion may be a main problem within the Ethiopian highlands. The Awash River basin is one among the Ethiopian highlands suffering from a high rate of surface erosion. Sediment inflow rates of reservoirs and spatial distribution of sediment yield (SY) are required at the sub-basin level to develop alternative watershed management practices. Hence, this study aimed toward estimating SY within the upper Awash River by using the soil and water assessment tool. The spatial, weather, hydrological, reservoir input, and water withdrawal data were collected and analyzed. The model had adjusted and verified for both flow and sediment. The graphical comparison and statistical indicators, coefficient of determination (R2), Nash–Sutcliffe efficiency (NSE), root-mean-square error standard deviation ratio (RSR) and percent bias (PBIAS) had used to evaluate the model's performance. Monthly streamflow and SY estimates were found to be reliable (R2 = 0.78–0.83, NSE = 0.75–0.82, RSR = 0.43–0.5 and PBIAS = 0.1–8.8) based on the model calibration and validation results. After calibration, the simulated average annual SY estimated was 22,109.5 t yr-1at the outlet, with an average spatial distribution of 6.52 t ha-1 yr-1. The model prediction outcomes showed that about 26.16% of the Awash Melkasa watershed, located in southwestern direction, is an erosion-prone area with a mean annual SY ranging from 10 to 18.54 t ha-1 yr-1execiding tolerable soil loss. These sub-basins need prior mitigation measures to reduce soil losses from the catchment.

4

Modeling the impacts of climate change on hydrological processes in the Baro–Akobo River basin, Ethiopia

Mengistu Abiy Getachew, Woldesenbet Tekalegn Ayele, Dile Yihun Taddele, Bayabil Haimanote Kebede

Acta Geophysica

|

2023

|

Vol. 71, no. 4

1915--1935

EN

Understanding the impacts of climate change on basin hydrology is critical for developing effective water management practices. This study was conducted to investigate climate change and its impact on the hydrological processes of the Baro–Akobo River basin in Ethiopia. Five bias-corrected regional climate models and their ensemble were developed to examine future climate changes in the 2030s (2021–2050) and 2080s (2071–2100) periods under the two Representative Concentration Pathways (RCP) 4.5 and RCP8.5 scenarios compared to a baseline (1981–2010) period. The calibrated model performed well with Nash–Sutcliffe efficiency and coefficient of determination of each 0.73 for daily and 0.89 and 0.9 for monthly simulation, respectively. Though all RCMs agree concerning the increasing direction of the 2030 and 2080s maximum and minimum temperature changes, there is inconsistency in the magnitude and direction of monthly projected rainfall changes. With the ensemble, the maximum and minimum temperatures will increase by 2.6 and 3.6 °C, respectively, and rainfall will decrease by 5% in the 2080s under RCP8.5 scenarios. The dry and wet season rainfall are expected to decrease by 19 and 3.7% under the RCP8.5 scenarios in the 2080s. Consequently, future climate change could cause a decrease in the annual surface runoff and water yield, while evapotranspiration could increase under the RCP4.5 and RCP8.5 scenarios. This study provides useful insights about potential climate change impacts on the hydrology of the basin, which could be useful to inform decision-makers in developing strategies such as water harvesting to mitigate the impact of climate change.

5

Stream flow dynamics under current and future land cover conditions in Atsela Watershed, Northern Ethiopia

Gebretekle Haftu, Nigusse Amare Gebremedhin, Demissie Biadgilgn

Acta Geophysica

|

2022

|

Vol. 70, no 1

305--318

EN

The aim of the present study was to detect land cover change for the last three decades and estimate its impact on stream flow dynamics under the current and future scenarios. Landsat satellite imageries were used for land cover classification for selected years (1987, 2002 and 2017). The effect of land cover change on stream flow was evaluated using SWAT model, and its performance was tested. The findings indicated significant land cover changes in the last three decades. Coverage of cultivated land (17%) and bare land (1%) in 1987 increased rapidly to 43 and 17% in 2017. Furthermore, there was 70% agreement between observed and simulated stream flow in both the calibration and validation phases. The stream flow of the watershed was changing significantly in response to land cover dynamics. The evaluation of hydrological response due to land cover change showed a monthly mean stream flow decrease by 12.7 m3 /s (−38%) in 1987 and 2017 in dry months. Nevertheless, it showed a monthly mean stream flow increase by 53.06 m3 /s (23%) in wet months. Similarly, between the years 2017 and 2047, the stream flow was estimated to increase by 42.84 m3 /s (15%) for wet months and a decrease by 13.52 m3 /s (−66%) for dry months. Generally, it can be concluded that land cover changes have significant impact on stream flow. Hence, establishing strong land use and water resource policies is an essential means for better evaluation and monitoring of water resource in the study area.

6

Modelling erosion and sedimentation in a small watershed, East Java, Indonesia

Sujarwo Mohamad Wawan, Indarto Indarto, Mandala Marga

Journal of Water and Land Development

|

2021

|

no. 50

265--273

EN

Changes in land use as a result of human activities may generate the alteration of hydrometeorological disasters. Erosion, sedimentation, floods and landslides frequently occur in the Sanenrejo watershed (±292 km2), located in East Java, Indonesia. In this paper, the soil and water assessment tool (SWAT) model is used to evaluate the hydrological processes in this small watershed. The digital elevation model (DEM) is used as the primary input for deriving the topographic and physical properties of the watershed. Other input data used for the modelling processes include soil type, land use, observed discharge data and climate variables. These data are integrated into the SWAT to calculate discharge, erosion and sedimentation processes. The existing observed discharge data used to calibrate the SWAT output at the watershed outlet. The calibration results produce Nash–Sutcliffe efficiency (NSE) of 0.62 and determination coefficient (R2) of 0.75, then the validation result of 0.5 (NSE) and 0.63 (R2). The middle area faced the highest erosion and sedimentation that potentially contribute to hydrometeorological disasters.

7

Modelling rainfall runoff for identification of suitable water harvesting sites in Dawe River watershed, Wabe Shebelle River basin, Ethiopia

Harka Arus E., Roba Negash T., Kassa Asfaw K.

Journal of Water and Land Development

|

2020

|

no. 47

186--195

EN

Scarcity of freshwater is one of the major issues which hinders nourishment in large portion of the countries like Ethiopia. The communities in the Dawe River watershed are facing acute water shortage where water harvesting is vital means of survival. The purpose of this study was to identify optimal water harvesting areas by considering socioeconomic and biophysical factors. This was performed through the integration of soil and water assessment tool (SWAT) model, remote sensing (RS) and Geographic Information System (GIS) technique based on multi-criteria evaluation (MCE). The parameters used for the selection of optimal sites for rainwater harvesting were surface runoff, soil texture, land use land cover, slope gradient and stakeholders’ priority. Rainfall data was acquired from the neighbouring weather stations while information about the soil was attained from laboratory analysis using pipette method. Runoff depth was estimated using SWAT model. The statistical performance of the model in estimating the runoff was revealed with coefficient of determination (R2) of 0.81 and Nash–Sutcliffe Efficiency (NSE) of 0.76 for monthly calibration and R2 of 0.79 and NSE of 0.72 for monthly validation periods. The result implied that there's adequate runoff water to be conserved. Combination of hydrological model with GIS and RS was found to be a vital tool in estimating rainfall runoff and mapping suitable water harvest home sites.

8

Assessment of the SWAT Model and the Parameters Affecting the Flow Simulation in the Watershed of Oued Laou (Northern Morocco)

Aqnouy Mourad, El Messari Jamal Eddine Stitou, Ismail Hilal, Bouadila Abdelmounim, Moreno Navarro Jesús Gabriel, Loubna Bounab, Mansour Mohammed Reda Aoulad

Journal of Ecological Engineering

|

2019

|

Vol. 20, nr 4

104--113

EN

This study evaluated the Soil and Water Assessment Tool (SWAT) model performance for modeling the portioning of rainfall in the Laou watershed (area: 940 km2) that extended over two different climatic settings in Morocco, (the Mediterranean sub-humid and the semi-arid). This research also investigated the significant parameters that affect the stream flow simulation. SWAT model was constructed during the period from 2004 to 2011. The modeled stream flow data was manually calibrated using flow gauges daily from 2004 to 2008 and validated for the volumetric flows from 2009 to 2011. SWAT model results indicate that 60% of the stream is provided by the base flow. The sensitivity analysis showed that out of 28 parameters, only 6 revealed meaningful effects on the flow simulation (CN2, ESCO, SOL_AWC, ALPHA_BF, CH_N2, CH_k2) and have the most significant influence. The model proved to be very sensitive to the base flow. Furthermore our outcome indicates that SWAT can successfully replicate the daily stream flows in Laou watershed with Nash-Sutcliffe (NSE) coefficients in the range of 0.76–0.84, R2 of 0.74–0.82, RSR of 0.52–0.41 and PBIS of 12.24–8.93 respectively. In addition SWAT was found to be suitable for both climatic regions in Laou watershed. These results reinforced the multi-functionality and reliability of SWAT as a hydrological model and a relevant tool for water resources management and controls.

9

Assessment of potential soil erosion and sediment yield in the semi‑arid N′fis basin (High Atlas, Morocco) using the SWAT model

Markhi A., Laftouhi N., Grusson Y., Soulaimani A.

Acta Geophysica

|

2019

|

Vol. 67, no. 1

263--272

EN

Arid and semi-arid regions face multiple problems in terms of water management, particularly where surface water is a primary resource. On the northern flank of the High Atlas Mountains (Morocco), deforestation has resulted in soil erosion and siltation of reservoirs. Better characterization of sediment yield is important for reducing the impact of siltation and prolonging the lifespan of dams. The Soil and Water Assessment Tool was used for modeling the N′fis basin in the southern Tensift watershed, leading to a better understanding of the rate of siltation behind Lalla Takerkoust dam. Runoff and sediment yield simulations were evaluated using graphical and statistical methods. The SWAT model performed well in estimating sediment load during the calibration period from 1990 to 2015 (Nash–Sutcliffe efficiency = 0.5–0.62, R2 = 0.5–0.61). The model enabled the determination of soil loss within each hydrological response unit in the watershed. The overall rate was approximately 123 t Ha−1 for an average annual rainfall of 315 mm yr−1. This high yield has to be taken into account for effective water-resources management in the N′fis basin.

10

Simulation of water cycle components in the Narmada River basin by forcing SWAT model with CFSR data

Goswami S. B., Kar S. C.

Meteorology Hydrology and Water Management. Research and Operational Applications

|

2018

|

Vol. 6, Iss. 1

13--25

EN

In the present study, an attempt has been made through a hydrological model (SWAT – Soil and Water Assessment Tool) to simulate water cycle components over the Narmada river basin, one of the largest rivers in the Indian peninsula. The model was forced with observed as well as CFSR rainfall data to calibrate surface runoff simulated by the model. The spatial and temporal variability of the water cycle components were examined by running the SWAT model for 30 years (1984-2013) at a daily time-scale using CFSR precipitation, temperature, humidity, winds and solar radiation. It was found that there are large variations in hydrological parameters simulated by the model from sub-basin to sub-basin and year to year. During the monsoon seasons, surface runoff is maximum but during other seasons, almost no surface runoff is seen as there is almost no rain. Groundwater increase is seen after about 1 month of rainfall peaks in the basin. Evapotranspiration has two peaks, one in March-April and the other in August. Much less evaporation takes place in the basin in the month of May. These components (other than surface runoff) are also sensitive to climatic forcing (winds, relative humidity and solar radiation in addition to temperature and rainfall) applied. Evapotranspiration increases when all the climatic parameters are used, which then reduces the water availability on the surface for percolation and groundwater recharge. However, rainfall is the key parameter which decides the hydrology in the Narmada basin. The SWAT model has been able to compute water balance at basin and sub-basin scales.

11

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

Piniewski M., Meresa H. K., Romanowicz R., Osuch M, Szcześniak M., Kardel I., Okruszko T., Mezghani A., Kundzewicz Z. W.

Acta Geophysica

|

2017

|

Vol. 65, no. 4

809--827

EN

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.

12

Wpływ jakości danych przestrzennych na wyniki modelowania obiegu wody w dorzeczu Parsęty

Gudowicz J.

Roczniki Geomatyki

|

2016

|

T. 14, z. 4(74)

437--446

PL

Numeryczne modele hydrologiczne i jakości wody bazujące na systemach informacji geograficznej wykorzystują różnorodne dane przestrzenne. Celem prac była ocena w jakim stopniu wyniki symulacji obiegu wody wykonane za pomocą modelu SWAT (Soil and Water Assessment Tool) są zależne od jakości danych wejściowych. Badaniami objęta została zlewnia Parsęty, która ze względu na jej wewnętrzną strukturę uważana jest za reprezentatywną dla obszarów młodoglacjalnych umiarkowanej strefy klimatycznej. W badaniach wykorzystano trzy różne źródła danych wysokościowych (DEM) oraz danych glebowych. W symulacjach uwzględniono dane meteorologiczne z wielolecia 1966-2010 pochodzące z 4 stacji meteorologicznych i 10 posterunków opadowych. Uwzględniono także zmiany pokrycia terenu i użytkowania ziemi jakie zaszły w analizowanym okresie przez wykorzystanie map z czterech horyzontów czasowych (1975, 1990, 2000, 2006). Kalibrację i walidację modelu przeprowadzono wykorzystując dane pomiarowe IMGW z trzech posterunków hydrometrycznych na Parsęcie. Uzyskane wyniki pozwoliły na analizę zróżnicowania przestrzennego elementów bilansu wodnego oraz analizę serii czasowych odpływu wody. Wyniki poddane zostały ocenie przy zastosowaniu współczynników statystycznych: determinacji R2, efektywności modelu Nasha-Sutcliffa (NSE) oraz współczynnika odchylenia procentowego (PBIAS). Otrzymane rezultaty modelowania były zróżnicowane w zależności od wykorzystanych danych wejściowych. Największą zgodność danych symulowanych z pomiarowymi uzyskano wykorzystując dane charakteryzujące się wysoką dokładnością przestrzenną i tematyczną.

EN

GIS-based hydrological and water quality models are based on the use of a variety of spatial data. The aim of this study was to assess whether the SWAT (Soil and Water Assessment Tool) simulation results are dependent on the quality of input data. The subject of the research covered the Parsęta drainage basin which in view of its internal structure is considered representative for the last glacial lowlands within the temperate climatic zone. Three different sources of DEM and soil data were used in the study. The simulations included meteorological data for the years 1966-2010 from 4 meteorological stations and 10 precipitation stations. Land cover and land use changes that took place in the analyzed period were included owing to application of maps originating from four time periods (1975, 1990, 2000, 2006). Calibration and validation was performed on the basis of the data collected by the Institute of Meteorology and Water Management at three water gauging stations on the Parsęta river. The results allowed the analysis of the spatial diversity of water balance elements and variability analysis of time series of water outflow. The results were subject to assessment by statistical methods: R2 determination coefficient, Nash-Sutcliffe efficiency coefficient (NSE), percent bias coefficient (PBIAS). The obtained results varied depending on the applied input data. The best consistency of the simulated data with the measurement data was obtained using data with the high spatial and thematic accuracy.

13

Curonian Lagoon drainage basin modelling and assessment of climate change impact

Čerkasova N., Ertürk A., Zemlys P., Denisov V., Umgiesser G.

Oceanologia

|

2016

|

No. 58 (2)

90--102

EN

The Curonian Lagoon, which is the largest European coastal lagoon with a surface area of 1578 km2 and a drainage area of 100,458 km2, is facing a severe eutrophication problem. With its increasing water management difficulties, the need for a sophisticated hydrological model of the Curonian Lagoon's drainage area arose, in order to assess possible changes resulting from local and global processes. In this study, we developed and calibrated a sophisticated hydrological model with the required accuracy, as an initial step for the future development of a modelling framework that aims to correctly predict the movement of pesticides, sediments or nutrients, and to evaluate water-management practices. The Soil and Water Assessment Tool was used to implement a model of the study area and to assess the impact of climate-change scenarios on the run-off of the Nemunas River and the Minija River, which are located in the Curonian Lagoons drainage basin. The models calibration and validation were performed using monthly streamflow data, and evaluated using the coefficient of determination (R2) and the Nash-Sutcliffe model efficiency coefficient (NSE). The calculated values of the R2 and NSE for the Nemunas and Minija Rivers stations were 0.81 and 0.79 for the calibration, and 0.679 and 0.602 for the validation period. Two potential climate-change scenarios were developed within the general patterns of near-term climate projections, as defined by the Intergovernmental Panel on Climate Change Fifth Assessment Report: both pessimistic (substantial changes in precipitation and temperature) and optimistic (insubstantial changes in precipitation and temperature). Both simulations produce similar general patterns in river-discharge change: a strong increase (up to 22%) in the winter months, especially in February, a decrease during the spring (up to 10%) and summer (up to 18%), and a slight increase during the autumn (up to 10%).

14

Modelowanie transportu materiału zawieszonego w dorzeczu Parsęty z uwzględnieniem zróżnicowanych rozdzielczości danych przestrzennych

Gudowicz J.

Landform Analysis

|

2015

|

Vol. 30

57--64

PL

Celem pracy jest przedstawienie modelu hydrologicznego dla dorzecza Parsęty opartego o system informacji geograficznej oraz prezentacja uzyskanych wyników modelowania w zakresie odpływu materiału zawieszonego. W badaniach wykorzystano model SWAT (Soil and Water Assessment Tool) zintegrowany za pomocą aplikacji ArcSWAT z oprogramowaniem ArcGIS. Wyniki poddane zostały ocenie przy zastosowaniu współczynników statystycznych: determinacji R2, efektywności modelu Nasha-Sutcliffa (NSE) oraz współczynnika odchylenia procentowego (PBIAS). Ocenę otrzymanych rezultatów modelowania wykonano pod kątem ich zróżnicowania w zależności od zastosowanych przestrzennych danych wejściowych. Stwierdzono, że najbardziej zgodne z danymi obserwowanymi były wyniki modelowania uzyskane z zastosowaniem danych przestrzennych o najwyższej rozdzielczości.

EN

The aim of this study was to present a GIS-based hydrological model developed for the Parsęta drainage basin and presentation of the results in terms of the suspended sediment outflow. SWAT (Soil and Water Assessment Tool) model integrated by the ArcSWAT application with the ArcGIS software was used in the study. The results were subject to assessment by statistical methods: R2 determination coefficient, Nash-Sutcliffe efficiency coefficient (NSE), percent bias coefficient (PBIAS). The evaluation of the results was performed based on their differentiation depending upon the spatial input data. The most consistent with the observed data were modeling results obtained from the use of high resolution spatial data.

15

Modelowanie wpływu zmian głębokości orki na ładunek azotu w wodach powierzchniowych

Śmietanka M., Szeptycki A.

Problemy Inżynierii Rolniczej

|

2014

|

R. 22, nr 1

43--56

PL

Wobec niewielkich zasobów wód w Polsce ochrona ich jakości jest ważnym zagadnieniem. Do zwiększenia ilości azotu w wodach w największym stopniu przyczynia się działalność rolnicza. Wpływ poszczególnych działań na ilość uwalnianego do wód powierzchniowych azotu można badać, wykorzystując modele komputerowe. W badaniach wykorzystano model SWAT (Soil and Water Assessment Tool), do oceny wpływu zmian głębokości orki na ładunek azotu w cieku. Badania przeprowadzono na zlewni górnej Zgłowiączki w centralnej Polsce. Model zasilono danymi o glebach, pogodzie, użytkowaniu ziemi, ukształtowaniu terenu oraz rodzaju i terminach zabiegów agrotechnicznych. Następnie został on skalibrowany i zwalidowany. W uzyskanym modelu przetestowano trzy scenariusze ze spłyconą orką (22, 20 oraz 17 cm). W wyniku badań stwierdzono brak lub bardzo niewielki wpływ głębokości orki na ilość azotu w punkcie zamykającym zlewnię testową.

EN

Poland has small water resources, so it is important to protect them. Agriculture is one of the biggest contributors increasing the amount of nitrogen in water. The impact of different management practices on the amount of nitrogen released to surface water can be studied using computer models. The study used the SWAT model to assess the impact of changes in the depth of plowing on nitrogen load in the stream. The study was conducted on the upper catchment Zgłowiączka in central Poland. After feeding the model with necessary data (land use, soil, weather, DEM) it was calibrated and validated. In the obtained model three scenarios with shallower plowing (22, 20 and 17 cm) were tested. The results showed no or very little effect of the depth of plowing on the amount of nitrogen at the point of closing the test basin.

16

The influence of permanent grasslands on nitrate nitrogen loads in modelling approach

Śmietanka M.

Journal of Water and Land Development

|

2014

|

no. 21

63--70

EN

The water pollution in areas with intensive agriculture is growing rapidly. Computer model is a tool which can help in finding solutions for water pollution reduction and help in creation of catchment management plans. In this research the SWAT model (Soil and Water Assessment Tool) was used to test the influence of introduction of permanent grasslands into the catchment on nitrate nitrogen load in surface water. Small catchment of upper Zgłowiączka River in central Poland with intensive agriculture was chosen as a test site. Model was fed with data about land use, soils, weather, elevation and management practices and calibrated and validated using flow data and nitrate nitrogen loads data. Then 2 scenarios with land use change were tested. A part of arable land was changed into permanent grasslands. The results show that permanent grasslands are effective in reducing nitrate nitrogen load. The load was reduced by 19% when permanent grasslands constituted 10% of arable land and by 38% with permanent grasslands taking up 20% of arable land.

PL

Zanieczyszczenie wody substancjami biogennymi pochodzenia rolniczego zwiększa się na obszarach intensywnie rolniczo użytkowanych. Wykorzystując model komputerowy, można wskazać skuteczne sposoby zmniejszenia ilości biogenów spływających do wód. W niniejszych badaniach wykorzystano model SWAT do oceny wpływu wprowadzenia trwałych użytków zielonych do zlewni na ładunek azotu w cieku. Badania przeprowadzono w małej zlewni rolniczej na Kujawach – górnej Zgłowiączki. W ramach badań symulowano wprowadzenie na obszar zlewni trwałych użytków zielonych zajmujących 10 i 20% powierzchni gruntów ornych. W wyniku modelowania stwierdzono, że znacząco zmniejszył się ładunek azotu w cieku w punkcie zamykającym zlewnię. W warunkach 10-procentowego udziału trwałych użytków zielonych odnotowano zmniejszenie ładunku od kilku procent do ponad 20. Gdy udział ten wynosił 20%, zmniejszenie to wyniosło od kilku procent do ponad 40% ładunku wyjściowego.

17

Application of SWAT model to small agricultural catchment in Poland

Brzozowski J., Miatkowski Z., Śliwiński D., Smarzyńska K., Śmietanka M.

Journal of Water and Land Development

|

2011

|

no. 15

157-166

EN

Poland is obliged, like the other EU countries, to implement the Water Framework Directive - WFD (2000/60/WE) by the end of 2015. The main objective of WFD is to provide normative quality of all water resources. To reach this goal reduction of water polluter emission to the environment is needed. Our project focuses on pollution from agricultural sources which share in global pollution is high and growing still. As a pilot area, where the WFD is going to be implemented, small agricultural Zgłowiączka catchment was chosen. The state monitoring of surface water quality for the catchment is conducted in three points along the Zgłowiaczka River. In each of these three points, nitrates concentration periodically significantly exceeds the allowable value of 50 mg NO3·dm-3. The highest average monthly values of nitrates concentration in years 1990-2007 occur in February, March and April, which indicates on agriculture as a source of pollution. The Zgłowiaczka catchment is an area where reduction of nitrogen run-off from agricultural lands to water resources is especially needed. The main topic of the research carried out in the Polish-Norwegian project is to propose different means for reduction of migration of nitrate to surface water based on modeling approach. In the paper a conception of creating buffer zones using SWAT model is presented. We considered fitting the buffer zone width, depending on the flow rate of water flowing from the fields to the stream. Using SWAT model interface a map of potential flow under the conditions of the intensive precipitation was generated. The next step was distribution over the whole Zgłowiączka catchment, places with high density of the temporal streams network. It was done using GRASS program. The map of stream "density" was done by assigning the raster number which is the sum of raster in the neighbourhood (radius of neighbourhood smaller or equal 25 raster). The choice of the most endangered subbasins was done on base of visual evaluation of the surface flow density map. It is visible in the results that filter strips on endangered areas are far more effective and therefore more required. If the width of the vegetated buffer strips is not sufficient, it will not attain the desired effectiveness. Conversely, if the width is too great, it will cause agricultural land waste, preventing farmers' interest in cooperating with environmental preservation efforts. For the above reasons, it is important to set a reasonable width range. According to the results we are suggesting wider buffer zones in endangered subbasins and narrow in other subbasins.

PL

Polska, podobnie jak pozostałe kraje członkowskie Unii Europejskiej, jest zobowiązana do wdrożenia Ramowej Dyrektywy Wodnej - RDW (2000/60/WE) do końca 2015 r. Głównym celem RDW jest osiągnięcie dobrego stanu ekologicznego wszystkich wód. Niezbędne jest więc ograniczenie emisji zanieczyszczeń zarówno do wód powierzchniowych jak i gruntowych. W polsko-norweskim projekcie pt. "Pilotażowe wdrożenie Ramowej Dyrektywy Wodnej i stworzenie narzędzia do zarządzania zlewnią" skupiono się na zanieczyszczeniach pochodzących ze źródeł rolniczych, których udział w ogólnym ładunku zanieczyszczeń jest bardzo znaczący i stale rośnie. W ramach projektu do wdrożenia RDW wybrano typowo rolniczą zlewnię górnej Zgłowiączki, zlokalizowaną na obszarze Kujaw. Na terenie zlewni od 1990 r. prowadzony jest państwowy monitoring jakości wód powierzchniowych przy ujściu cieku do Jeziora Głuszyńskiego, a od 2000 r. w dwóch monitoring uzupełniono o dwa dodatkowe punkty pomiarowo-kontrolne na długości cieku. W każdym z tych punktów stężenie azotanów okresowo kilkakrotnie przekraczało dopuszczalną wartość 50 mg·dm-3. Największe miesięczne wartości stężenia w latach 1990-2007 notowano w lutym, marcu i kwietniu, co wskazuje na pochodzenie zanieczyszczeń z rozproszonych źródeł rolniczych. W związku z tym obszar zlewni górnej Zgłowiączki to teren, na którym ograniczenie rozpraszania azotanów z rolnictwa do środowiska jest szczególnie potrzebne. Głównym celem projektu jest zaproponowanie działań prowadzących do ograniczenia rozpraszania azotanów do wód i przeanalizowanie ich skuteczności z wykorzystaniem modelowania. Do tego celu zastosowano hydrologiczny model SWAT, stworzony w celu przewidywania wpływu użytkowania terenu zlewni na jakość wód w długim czasie. W artykule przedstawiono koncepcję wykorzystania modelu SWAT do optymalnego określenia rozmieszczenia i szerokości stref buforowych na obszarze zlewni jako jednej z metod, prowadzących do ograniczenia procesu rozpraszania azotanów do wód.

18

Komputerowe wspomaganie tworzenia pasów buforowych i wyznaczania ich efektywności

Śmietanka M., Śliwiński D., Brzozowski J.

Problemy Inżynierii Rolniczej

|

2009

|

R. 17, nr 1

61-72

PL

Intensywnie rolniczy obszar zlewni Zgłowiączki na Kujawach jest określony przez RZGW jako wrażliwy, o szczególnie dużych przekroczeniach wartości normatywnych azotanów i fosforanów w wodach powierzchniowych. Dlatego istnieje potrzeba szybkich działań zmierzających do poprawy sytuacji. W niniejszym projekcie wykorzystywany jest model SWAT (Soil and Water Assessment Tool). Pozwala on przewidywać wpływ praktyk rolniczych na wody, osady, plony w długich okresach czasu na obszarach o zróżnicowanych warunkach przyrodniczych. Model wykorzystano między innymi do stworzenia mapy potencjalnego spływu powierzchniowego. Na tej podstawie wybrano obszary szczególnie zagrożone spływem zanieczyszczeń. Zaproponowano stworzenie tam stref buforowych i testowano ich efektywność. Strefy buforowe w obszarach zagrożonych większym spływem zanieczyszczeń wykazują większe pochłanianie zanieczyszczeń na jednostkę powierzchni. Końcowym efektem jest propozycja ustanowienia tam stref buforowych o zmiennej szerokości, dostosowanych do lokalnych warunków. Strefy szersze powinny się znaleźć na obszarach szczególnie zagrożonych, a węższe na pozostałych. Pozwoli to chronić jakość wód, a jednocześnie zachować maksymalnie dużą powierzchnię pod uprawy rolnicze.

EN

Zgłowiączki catchment area of intensive agriculture in Kujawy region, is determined by the local experts as a sensitive terrain, highly exceeding the standard nitrates and phosphates contents in surface waters. Thus, there exists an urgent need of effective activities improving the situation. In this study the SWAT (Soil and Water Assessment Tool) computer model was applied to foresee the impact of agricultural practices on the waters, deposits and yields within the long periods, on terrains of differentiated natural circumstances. The model was used, among the others, to create a map of potential surface water runoff. On such a basis the areas particularly threatened by pollution down flow were selected. Formation of the buffer zones were proposed and their effectiveness was tested. Buffer zones on the areas threatened by increased pollution down flow showed more intensive pollution absorption per surface unit. The final effect is a proposal of arranging there the buffer zones of differentiated width, adapted to local conditions. Wider zones should be arranged on the areas particularly threatened, while on the rest - the narrower ones. That will protect the water quality at retaining the maximum acreage under agricultural crops.