Download or read book Modelling Water Quality of the Pike River Watershed Under Four Climate Change Scenarios written by and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The impacts of climate change on the hydrology and water quality of the Pike River watershed, an important contributor of nutrient loads to northern Lake Champlain, were predicted for the time horizon 2041-2070. Four water quality scenarios were simulated using a version of the Soil and Water Assessment Tool (SWAT) modified to suit Québec's agroclimatic conditions. Three of the scenarios were generated using climates simulated with the Fourth Canadian Regional Climate Model (CRCM4). The fourth scenario was generated using the climate simulated with the Arpege Regional Climate Model. SWAT was independently calibrated for the period 2001-2003, and then validated for the periods of 2004-2006 and 1980-2000, before inputting the climate scenarios. Potential mean changes predicted by these scenarios were then analysed for the evapotranspiration, surface and subsurface runoff, stream flow, sediment yields, and total phosphorus and nitrogen.After calibration, mean annual evapotranspiration, surface and subsurface flow as well as water percolation were found to correspond satisfactorily with the hydrology of the basin. Likewise, monthly predicted stream flow compared reasonably well with observed stream flow. The performance of SWAT in simulating sediment and nutrient yields was clearly improved after calibration but did not always reach standards of acceptability. As for climate change results, only one scenario predicted a significant increase in mean annual stream flow and nutrient loadings. However, when considering shorter time spans, simulations predicted significant changes including a winter stream flow two to three times greater than current stream flow and earlier spring floods. The identified causes are the early onset of spring snowmelt, a greater number of rainfall events and snowmelt episodes caused by higher winter and spring temperatures. In contrast, peak flows in April, as well as summer stream flow, appear to decrease but not always significantly. Nutrient

Download or read book Modelling Water Quality of the Pike River Watershed Under Four Climate Change Scenarios written by Colline Gombault and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The impacts of climate change on the hydrology and water quality of the Pike River watershed, an important contributor of nutrient loads to northern Lake Champlain, were predicted for the time horizon 2041-2070. Four water quality scenarios were simulated using a version of the Soil and Water Assessment Tool (SWAT) modified to suit Québec's agroclimatic conditions. Three of the scenarios were generated using climates simulated with the Fourth Canadian Regional Climate Model (CRCM4). The fourth scenario was generated using the climate simulated with the Arpege Regional Climate Model. SWAT was independently calibrated for the period 2001-2003, and then validated for the periods of 2004-2006 and 1980-2000, before inputting the climate scenarios. Potential mean changes predicted by these scenarios were then analysed for the evapotranspiration, surface and subsurface runoff, stream flow, sediment yields, and total phosphorus and nitrogen.After calibration, mean annual evapotranspiration, surface and subsurface flow as well as water percolation were found to correspond satisfactorily with the hydrology of the basin. Likewise, monthly predicted stream flow compared reasonably well with observed stream flow. The performance of SWAT in simulating sediment and nutrient yields was clearly improved after calibration but did not always reach standards of acceptability. As for climate change results, only one scenario predicted a significant increase in mean annual stream flow and nutrient loadings. However, when considering shorter time spans, simulations predicted significant changes including a winter stream flow two to three times greater than current stream flow and earlier spring floods. The identified causes are the early onset of spring snowmelt, a greater number of rainfall events and snowmelt episodes caused by higher winter and spring temperatures. In contrast, peak flows in April, as well as summer stream flow, appear to decrease but not always significantly. Nutrient delivery to the lake significantly increased in winter and occurred earlier in the year as a consequence of hydrological changes. A three- to four-fold increase in subsurface flow was also observed in winter which may increase nutrient losses through this pathway." --

Download or read book Integrated Soil and Water Management Selected Papers from 2016 International SWAT Conference written by Karim Abbaspour and published by MDPI. This book was released on 2018-03-15 with total page 501 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Integrated Soil and Water Management: Selected Papers from 2016 International SWAT Conference" that was published in Water

Download or read book Assessing the Impacts of Climate Change on Fluvial Processes written by Robert Baidoc and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Watershed models are an important tool in regional planning and conservation efforts. They can provide valuable insight into the potential impacts of different land use changes and future climate change scenarios on water resources, which can lead to better, more informed decision making. Climate impacts, in particular, add a new level of uncertainty with regard to freshwater supplies as the hydrological cycle is intimately linked with changes in atmospheric temperatures. The main objective of this study is to investigate the extent of long-term climate change on streamflow and stream temperature within an agriculturally defined watershed in Northern Ontario. For this purpose, the Soil and Water Assessment Tool (SWAT) model was utilized to provide a better understanding of how hydrological processes in the Slate River Watershed will alter in response to long-term climate change scenarios. The SWAT model is a distributed/semi-distributed physically-based continuous model, developed by the USDA for the management of agricultural watersheds, and is currently one of the most popular watershed-based models used in climate change analysis of snowmelt dominated watersheds. Historic flow data was compared to a discharge model that reflected four climate models driven by SRES A1B and A2 through the middle and end of the century. Hydrology modelling was enhanced with stream temperature analysis to gain a comprehensive understanding of the extent of changing climate regimes on the Slate River. A linear regression approach representing a positive relationship between stream temperature and air temperature was used to determine the thermal classification of the Slate River. Our results indicated that the Slate River was well within the warm-water character regime. Unusual high stream temperatures were recorded at mid- August; these were accompanied by low water levels and a lack of riparian vegetative cover at the recording site, providing a possible explanation for such temperature anomalies. The results of the flow discharge modelling supported our hypothesis that tributaries within our ecosystem would experience increasing water stress in a warming climate as the average total discharge from the Slate River decreased in both climate scenarios at the middle and end of the century. Although the lack of accurate subsurface soil data within the study region prevented our discharge model from quantifying the changes in stream discharge, the strong correlation between the observed and simulated flow data as reflected by a 0.92 r2 statistic gave us confidence that discharge from the Slate River will continue to follow a decreasing trend as climate change persists into the future. This study aims to support the future endeavours of hydrologic modelling of watersheds in Northern Ontario by illustrating the current capabilities and limits of climate change analysis studies within this region.

Download or read book Modelling the Impact of Climate Change on Water Resources written by C. Fai Fung and published by John Wiley & Sons. This book was released on 2011-07-05 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt: The quantitative assessment of the impact of climate change on water availability and water resources management requires knowledge of climate, hydro(geo)logical and water resources models, and particularly the relationships between each of them. This book brings together world experts on each of these aspects, distilling each complex topic into concise and easy to understand chapters, in which both the uses and limitations of modelling are explored. The book concludes with a set of case studies using real-life examples to illustrate the steps required and the problems that can be faced in assessing the potential impacts of climate change on water resource systems. For students, scientists, engineers and decision-makers alike, this book provides an invaluable and critical look at the information that is provided by climate models, and the ways it is used in modelling water systems. A key focus is the exploration of how uncertainties may accrue at each stage of an impacts assessment, and the reliability of the resulting information. The book is a practical guide to understanding the opportunities and pitfalls in the quantitative assessment of climate change impacts and adaptation in the water resource sector.

Download or read book Scenario based impact assessment of global and regional change on the semi natural flow regime written by Mikołaj Piniewski and published by diplom.de. This book was released on 2014-04-01 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Globally, freshwater ecosystems are considered to be under severe threat from human pressure and climate change (Vörösmarty et al., 2010). Malmqvist and Rundle (2002) suggest that running water is the most impacted upon ecosystem on Earth due to being surrounded by dense human settlements and exploited for domestic and industrial water supply, irrigation, electricity generation and waste disposal. For example, the progressive over-exploitation of surface water resources for irrigation and urban uses in the Colorado River Basin has resulted most years in no runoff reaching the river’s delta (Gleick, 2003) [...]. Hereafter, natural and anthropogenic driving forces will be referred to as global and regional driving forces, respectively. The future effects of these forces up to the 2050s will be assessed in quantitative scenarios implemented in a hydrological model. It is believed that using this nomenclature (i.e. global and regional instead of natural and anthropogenic) better reflects considered environmental stressors, since global-scale driving forces will include not only climatic change but also changes in CO2, atmospheric carbon dioxide and plant physiological parameters, whereas regional-scale driving forces will include changes in land use, agriculture development and agricultural water management. Hence, the difference is that the first group of driving forces acts globally and independently on the study area, whereas the second group includes factors that are specific to the study area. Furthermore, in order to expand on the title of this thesis, impacts in the present study will be assessed not only on the flow regime as such, but also on its ecological functions, i.e. on the environmental flow regime. This is motivated mainly by the semi-natural character of the study area, that is unique in Poland and in Europe, but it also underlines the novelty of this thesis, as going beyond the pure impacts on the flow regime in a scenario-modelling framework is rare in hydrological science, if achieved at all.

Download or read book Modelling the Effects of Climate Change on the Surface and Subsurface Hydrology of the Grand River Watershed written by Dennis Colautti and published by . This book was released on 2010 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: A numerical modelling analysis of climate change's precipitation effects on the long-term, averaged surface and subsurface hydrology of the Grand River Watershed (GRW) was undertaken in order to assess possible areas of concern for decision makers in the water management sector. The physically-based, fully-integrated and variably-saturated 3-D surface-subsurface numerical simulator, HydroGeoSphere, was used to drive five mid-21st century climate change scenarios, developed from multiple general circulation models. Calibration involved altering measured and literature-derived hydraulic conductivity and precipitation distribution estimates, resulting in very good matching between observed and simulated long-term average surface flow at all gauge stations. Subsurface head results, too, matched observed heads quite well, though groundwater linkage to neighbouring watersheds was not included. When groundwater linkage to neighbouring watersheds was allowed, via regional Dirichlet boundary conditions used in a parent study, groundwater throughput was deemed to be unrealistic. All but one of the climate change scenarios caused an increase in both river discharge and water table elevation, with the greatest climate perturbations causing the greatest increases. For Scenario 1 (5% less precipitation than the 1960-to-1999 average), percentage discharge changes averaged -15% over all gauge stations. For the other scenarios (more precipitation than average), the inter-scenario discharge response ranged from approximately +12% to +59%. In general the range of inter-subcatchment response was greater than was the range for intra-subcatchment response; the greatest percentage response was consistently in the Speed River subcatchment, while the least was consistently in the Nith and Conestogo subcatchments. The exception was the application of less-than-average precipitation to the Grand River, whose gauge stations reported percentage changes in discharge that varied more substantially from one another. Subsurface hydrology reacted to the climate change scenarios in much the same manner as did the surface hydrology, with all climate change scenarios associated with a precipitation increase unsurprisingly resulting in higher total hydraulic heads throughout the entire domain. Specifically, the minimum and maximum mean head increases among the climate change scenarios were 0.41 m and 1.25 m respectively, while the only decrease was an average of 0.55 m. Similarly, the depth from the ground surface to the water table decreased in most scenarios, the maximum water table rise being 1.08 m and the minimum 0.36 m. When precipitation was allowed to decrease by 5% relative to the long-term average, the average water table elevation decreased by 0.48 m. However the water table's pattern of high and low points remained very much the same among all climate change scenarios, suggesting that basin-wide groundwater flow patterns may not be among the hydrological measures most sensitive to climate change. Groundwater recharge, like almost all other components of the water budget, changed in linear proportion to the climate forcing and in agreement with GRW recharge estimates developed by others. Evapotranspiration, which met potential evapotranspiration in all scenarios due to the constant application of precipitation, was the only element of the water budget that did not increase, even though the water table was elevated closer to the rooting zone by most of the climate scenarios. On a smaller scale, changes in flow patterns may well be expected, given that zones of infiltration were observed to intensify with most of the climate forcing.

Download or read book Journal of Soil and Water Conservation written by and published by . This book was released on 2017 with total page 818 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vol. 25, no. 1 contains the society's Lincoln Chapter's Resource conservation glossary.

Download or read book Climate Change and Water Resources in South Asia written by M. Monirul Qader Mirza and published by CRC Press. This book was released on 2005-06-30 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses the most pressing water resource issues in South Asia, particularly in relation to climate change and variability. This is a region characterised by abundant water during the monsoon, when devastating floods occur, and by scarcity of water and droughts during the dry period. These extreme events often cause substantial damage to

Download or read book Probabilistic Climate Change Scenarios and Impacts on Water Resources and Ecology written by and published by . This book was released on 2009 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume in the 'Environment Agency Science Report' series features case studies which demonstrate the added value of using large climate model ensembles when assessing climate change impacts on water resources and river ecology and exploring possible adaptation pathways.

Download or read book Modeling Environmental Change written by Elizabeth Allen and published by . This book was released on 2019 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication introduces policy makers and natural resource managers to the use of scenarios in environmental modeling. Managers increasingly recognize that the climate is changing and that those changes pose a threat that must be understood in more detail and incorporated into planning decisions at all scales. High quality information about likely environmental change impacts is critically important to help decision-makers address risks in an adaptive manner. To provide concrete examples of the types of scenarios that may be considered in making management decisions, we draw from the 2016 Columbia River Basin Long-Term Water Supply and Demand Forecast, which the Washington Department of Ecology publishes every five years to assist stakeholders in planning for future water resource conditions. There are many different approaches to developing and testing scenarios to inform decision-making. When decision-makers understand how scenarios are developed and how models are run, they can better use model outputs to inform their management decisions.

Download or read book Modelling the impact of climate change on water quality in rivers and reservoirs Phase 2 written by D. Boorman and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Case Study for Assessing the Hydrologic Impacts of Climate Change at the Watershed Scale written by Martinus Hubertus Brouwers and published by . This book was released on 2007 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the advent of the industrial era atmospheric concentrations of greenhouse gases have been on the rise leading to increasing global mean temperatures. Through increasing temperatures and changes to distributions of precipitation, climate change will intensify the hydrologic cycle which will directly impact surface water sources while the impacts to groundwater are reflected through changes in recharge to the water table. The IPCC (2001) reports that limited investigations have been conducted regarding the impacts of climate change to groundwater resources. The complexity of evaluating the hydrologic impacts of climate change requires the use of a numerical model. This thesis investigates the state of the science of conjunctive surface-subsurface water modeling with the aim of determining a suitable approach for conducting long-term transient simulations at the watershed scale. As a result of this investigation, a coupled modeling approach is adopted using HELP3 to simulate surface and vadose zone processes and HydroSphere to simulate saturated flow of groundwater. This approach is applied to the Alder Creek Watershed, which is a subwatershed of the Grand River Watershed and located near Kitchener-Waterloo, Ontario. The Alder Creek Watershed is a suitable case study for the evaluation of climate change scenarios as it has been well characterized from previous studies and it is relatively small in size. Two contrasting scenarios of climate change (i.e., drier and wetter futures) are evaluated relative to a reference scenario that is based on the historical climatic record of the region. The simulation results show a strong impact upon the timing of hydrologic processes, shifting the spring snow melt to earlier in the year leading to an overall decrease in runoff and increase in infiltration for both drier and wetter future climate scenarios. Both climate change scenarios showed a marked increase to overall evapotranspiration which is most pronounced in the summer months. The impacts to groundwater are more subdued relative to surface water. This is attributed to the climate forcing perturbations being attenuated by the shift of the spring snow melt and the transient storage effects of the vadose zone, which can be significant given the hummocky terrain of the region. The simulation results show a small overall rise of groundwater elevations resulting from the simulated increase in infiltration for both climate change scenarios.

Download or read book Canadian Journal of Soil Science written by and published by . This book was released on 2007 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling Stream Discharge and Nitrate Loading in the Iowa Cedar River Basin Under Climate and Land Use Change written by Lance Olot Le and published by . This book was released on 2015 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Soil and Water Assessment Tool (SWAT) model was developed for the Iowa-Cedar River Basin (ICRB), a 32,660 km2 watershed dominated by agricultural land cover (~70%) to simulate hydrology and water quality for the prediction of stream discharge, nitrate loads, and nitrate concentration under climate and land use change scenarios. Iowa exports as much as 20% of the nitrogen entering the Gulf of Mexico at the mouth of the Mississippi, contributing to Gulf hypoxia as well as local threats to water quality in the ICRB. The model utilized a combined autocalibration and sensitivity procedure incorporating Sequential Uncertainty Fitting (SUFI) and generalized additive models. This procedure resulted in Nash-Sutcliffe Efficiency (NSE) goodness-of-fit statistics that met literature guidelines for monthly mean stream discharge (NSE>̲0.60) and daily nitrate load (NSE>̲0.50). Artificial neural networks coupled with SWAT stream discharges aided in the simulation of daily mean nitrate concentrations that met the literature guideline (NSE>̲0.50). The North American Regional Climate Change Assessment Program (NARCCAP) provided an ensemble of 11 climate change scenarios. NARCCAP is a multi-institutional effort to simulate climate change at the mesoscale by downscaling global circulation models (GCM) with regional climate models (RCM). The resulting GCM-RCM produced synthetic precipitation and temperature time-series that drove the SWAT simulations and scenarios. The land use scenarios were a collaboration with the U.S. Army Corps of Engineers, using a rule-based GIS method to generate scenarios that (1) maximized agricultural productivity, (2) improved water quality and reduced flooding, and (3) enhanced local biodiversity. The SWAT simulations and ensemble climate change scenarios resulted in a warmer and wetter climate with greater and more extreme discharge in all seasons except summer where the models indicate a somewhat higher probability of extreme low flows (p-value

Download or read book Modelling of Environmental Change Impacts on Water Resources and Hydrological Extremes in Germany written by Shaochun Huang and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water resources, in terms of quantity and quality, are significantly influenced by environmental changes, especially by climate and land use changes. The main objective of the present study is to project climate change impacts on the seasonal dynamics of water fluxes, spatial changes in water balance components as well as the future flood and low flow conditions in Germany. This study is based on the modeling results of the process-based eco-hydrological model SWIM (Soil and Water Integrated Model) driven by various regional climate scenarios on one hand. On the other hand, it is supported by statistical analysis on long-term trends of observed and simulated time series. In addition, this study evaluates the impacts of potential land use changes on water quality in terms of NO3-N load in selected sub-regions of the Elbe basin. In the context of climate change, the actual evapotransipration is likely to increase in most parts of Germany, while total runoff generation may decrease in south and east regions in the scenario period 2051-2060. Water discharge in all six studied large rivers (Ems, Weser, Saale, Danube, Main and Neckar) would be 8 - 30% lower in summer and autumn compared to the reference period (1961 - 1990), and the strongest decline is expected for the Saale, Danube and Neckar. The 50-year low flow is likely to occur more frequently in western, southern and central Germany after 2061 as suggested by more than 80% of the model runs. The current low flow period (from August to September) may be extended until the late autumn at the end of this century. Higher winter flow is expected in all of these rivers, and the increase is most significant for the Ems (about 18%). No general pattern of changes in flood directions can be concluded according to the results driven by different RCMs, emission scenarios and multi-realizations. An optimal agricultural land use and management are essential for the reduction in nutrient loads and improvement of water quality. In the Weiße Elster and Unstrut sub-basins (Elbe), an increase of 10% in the winter rape area can result in 12-19% more NO3-N load in rivers. In contrast, another energy plant, maize, has a moderate effect on the water environment. Mineral fertilizers have a much stronger effect on the NO3-N load than organic fertilizers. Cover crops, which play an important role in the reduction of nitrate losses from fields, should be maintained on cropland. The uncertainty in estimating future high flows and, in particular, extreme floods remain high due to different RCM structures, emission scenarios and multi-realizations. In contrast, the projection of low flows under warmer climate conditions appears to be more pronounced and consistent. The largest source of uncertainty related to NO3-N modelling originates from the input data on the agricultural management.

Download or read book Climate Change Impacts on Snowmelt Driven Streamflow in the Grand River Watershed written by Amy Dietrich and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Climate change is one of the most significant global environmental drivers threatening the quality and quantity of future water resources. Global temperature increases will have significant effects on the hydrologic regime of northern regions due to changes in snowfall and snowmelt. Considerable research has been conducted in western Canada to rigorously quantify snowmelt-driven streamflow processes, however, less focus has been directed towards understanding these processes in eastern Canada and Ontario. In the southern Ontario Grand River Watershed (GRW), snowmelt contributions to streamflow (freshet) make up a significant portion of the annual water yield, and the period of snowmelt is also of key concern for flood mitigation. This thesis aims to quantify historical and projected changes to timing and streamflow during freshet in the Nith River, an unregulated tributary of the Grand River. Climate data (temperature, rainfall, snowfall, and snow proportion) from observations and future scenarios were analyzed to quantify the contributions of climate conditions surrounding the timing and volume of the freshet. The annual timing of snowmelt-driven streamflow was quantified using centre time (CT), and streamflow volumes were quantified by various percentiles of streamflow (Qn) during four periods of the water year (October-December, January-February, March-April, and May-September). Historical trends in streamflow and climate data were examined using hydrometric data (1914-2016) of a stream gauge from the Water Survey of Canada, and climate data (1950-2016) from Environment and Climate Change Canada at two stations. Projected climate data were from an ensemble of models used in the Intergovernmental Panel on Climate Change's Fourth Assessment Report (AR4). A total of nine distinct models ran two scenarios from AR4 for the 2050s; moderate (B1) and high (A1B). These time-slice projections were then used to force the hydrologic model GAWSER to simulate future streamflow data. The results show that CT in the Nith River has advanced by 17 days, on average, from 1914 to 2016 (P=0.036), and the advance is projected to continue as a function of future emissions scenario (approximately 12 days for scenario B1, and 17 days for A1B). Historical CT was weakly negatively correlated with temperature (-0.51, P