738 Years of Global Climate Model Simulated Streamflow in the Nelson-Churchill River Basin PDF Download

Author: Michael John Fernandes Vieira
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Christina Anagnostopoulou
Publisher: MDPI
ISBN: 303650110X
Category : Science
Languages : en
Pages : 142

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- Water resources management should be assessed under climate change conditions, as historic data cannot replicate future climatic conditions. - Climate change impacts on water resources are bound to affect all water uses, i.e., irrigated agriculture, domestic and industrial water supply, hydropower generation, and environmental flow (of streams and rivers) and water level (of lakes). - Bottom-up approaches, i.e., the forcing of hydrologic simulation models with climate change models’ outputs, are the most common engineering practices and considered as climate-resilient water management approaches. - Hydrologic simulations forced by climate change scenarios derived from regional climate models (RCMs) can provide accurate assessments of the future water regime at basin scales. - Irrigated agriculture requires special attention as it is the principal water consumer and alterations of both precipitation and temperature patterns will directly affect agriculture yields and incomes. - Integrated water resources management (IWRM) requires multidisciplinary and interdisciplinary approaches, with climate change to be an emerging cornerstone in the IWRM concept.

Author: Amy Pryse-Phillips
Publisher:
ISBN:
Category :
Languages : en
Pages : 276

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Author: Sabin Shrestha (Civil engineer)
Publisher:
ISBN:
Category : Climatic changes
Languages : en
Pages : 148

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There is a widespread concern that climate change will lead to an increased frequency and intensity of extreme weather events in the 21st century. It is essential, from a watershed management point of view to understand how these alterations in the hydrologic regime would affect the existing water resources. This research, therefore, provides an overview of the hydrologic impacts on the Great Miami River Watershed in Ohio, USA due to projected climatic changes on both low flows and high flows. An extensively used hydrological model, the Soil and Water Assessment Tool (SWAT) was to evaluate the hydrological impacts of climate change. The multi-site model calibration and validation were performed using the SUFI-2 algorithm within SWAT-CUP. The model was calibrated (2005 - 2014) and validated (1995 - 2004) for monthly stream flows at the outlet resulting in Nash - Sutcliffe Coefficients of 0.86 and 0.83, respectively. An ensemble of ten downscaled and bias-corrected climate models from Fifth Phase Coupled Model Intercomparison Project (CMIP5) under two Representative Concentration Pathways(RCPs) 4.5 and 8.5 were used to generate a probable set of climate data (precipitation and temperature). The climate data were then fed into the SWAT model and hydrological changes in the stream in terms of daily discharge were produced for three time-frames: (2016 - 2043) as 2035s, (2044 - 2071) as 2055s, and (2072 - 99) as 2085s and compared against the baseline period (1988 - 2015). The findings from this research showed that low flows using both hydrological and biological indices would increase more than 100% in 2035s but eventually decrease slightly in the later part of the century (2085s). However, the Max Planck Institute Earth System Model (MPI-ESM-LR) used in this study predicted that the biological indices iv under RCP 8.5 would increase slightly at the beginning but decrease considerably in the middle and later part of the century. Analysis showed that the variability of the average 7-day low flows in each year would increase considerably for both emission scenarios. Furthermore, 75th percentile exceedance frequency of monthly low flows was found higher in September, October, and November during the study period. As for high flow analysis, the hydrological index for high flows (7Q10) from an ensemble of 10 climate models predicted to decrease consistently in future. When the results from the two RCPs are compared, high flows would decrease maximum by 22% in 2055s under RCP 8.5 and 21% in 2085s under RCP 4.5. However, the MIROC5 model in RCP 4.5 showed 1.2% increase in 7Q10 high flows during 2035s. The frequency of the 75th percentile non-exceedance flows was also projected to increase in the future. Under the RCP 4.5, the frequency becomes higher in 2055s whereas under the RCP 8.5 most frequent 75th percentile flow would occur in 2085s. Meanwhile, on a monthly scale, the peak would increase more on every month except January and December than that of historical records. The variability of peak discharge was also expected to increase in every other month in both scenarios. The peak would increase considerably especially in August, September, and October when compared to historical months, indicating relatively wetter months in the future years. Finally, this study has demonstrated the effects of changing climates projected by the climate models on extreme flow condition in the large agricultural watershed. The next step of the research will focus on further bias correction on simulated climate data and analysis for future.

Author: Andualem Shimeles
Publisher: LAP Lambert Academic Publishing
ISBN: 9783659336584
Category :
Languages : en
Pages : 104

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To assess how stream flow in Gilgel Abbay River Basin will be affected by climate change, the HadCM3 model, developed at the Hadley Centre in the United Kingdom, was used to generate medium-high and medium-low emission scenarios in this study. The statistical downscaling model was used to generate future possible local meteorological variables in the study area. The down-scaled data were then used as input to the Soil and Water Assessment Tool hydrological model to simulate the corresponding future stream flow regime in Gilgel Abbay River Basin. Three benchmark periods simulated were 2011-2040 (2020s), 2041-2070 (2050s), and 2071-2099 (2080s). The time series generated by HadCM3 and statistical downscaling method indicate a significant increasing trend in both maximum and minimum temperature values, and a decreasing trend in precipitation. The hydrologic impact analysis made with the downscaled temperature and precipitation time series as input to the SWAT model suggested an overall decreasing trend in annual and monthly stream flow in the study area, in three benchmark periods in the future. This should be considered by policymakers of water resources planning and management.

Author: Michael Peter Hanratty
Publisher:
ISBN:
Category :
Languages : en
Pages : 846

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Author: Ruud T. W. L. Hurkmans
Publisher:
ISBN: 9789085853985
Category :
Languages : en
Pages : 174

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Author: Stephanie E. Truitt
Publisher:
ISBN:
Category : Climatic changes
Languages : en
Pages : 0

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Stream temperatures in mountain streams in the western Cascade Mountains are heavily influenced by factors such as discharge, air temperature, and as in the case of the Nooksack River Basin in northwest Washington State; snow and glacial melt. The Nooksack basin is sensitive to warming climates due to the regions moderate Pacific maritime climate. Previous modeling studies in the upper Nooksack basins indicate a reduction in snowpack and spring runoff, and a recession of glaciers into the 21st century due to global climate change. How stream temperatures will respond to these changes is unknown. We use the Distributed Hydrology Soil Vegetation Model (DHSVM) coupled with a glacier dynamics model to simulate hydrology and the River Basin Model (RBM) to model stream temperature from present to the year 2090 in the North, Middle, and South forks of the Nooksack River basin. We simulate forecasted climate change effects on hydrology and stream temperature using gridded daily statically downscaled data from 10 global climate models (GCMs) of the Coupled Model Intercomparison Project Phase Five (CMIP5) with two different representative concentration pathways (RCP) RCP4.5 and RCP8.5. Simulation results project a trending increase in stream temperature into the 21st century in all three forks of the Nooksack. There is a strong correlation between rising stream temperatures and warming air temperatures, decreasing stream discharge; and snow and glacial meltwater. We find that the highest stream temperatures and the greatest monthly mean 7-day average of the daily maximum stream temperature (7-DADMax) values are predicted in the lower relief, unglaciated South Fork basin. For the 30 years surrounding the 2075 time period, the mouth of the South Fork is forecasted to have a mean of 115 days above the 16 °C 7-day average of the daily maximum stream temperature threshold. Streams in the Middle and North fork basins with higher elevations that sustain more snow and glacier ice are slower to respond to warming climates due to meltwater contributions, especially in the next 50 years. Towards the end of this century, when snowpack and glacial volume is greatly decreased, the buffering effect of meltwater declines, and the North and Middle forks experience larger increases in mean daily stream temperature. For the 30 years surrounding the 2075 time period, the mouths of the Middle and North forks are forecasted to have means of 35 and 23 days, respectively, above the 16 °C 7-DADMax threshold.

Author: Evan A. Paul
Publisher:
ISBN:
Category : Climatic changes
Languages : en
Pages : 0

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The Nooksack River in northwest Washington State provides freshwater for agriculture, municipal, and industrial use and serves as a vital habitat for endangered salmon, a resource that is of cultural and economic importance to the Nooksack Indian Tribe and the surrounding region. Due to the complex topography in the basin and the mild maritime climate of the Puget Sound region, streamflow in the Nooksack River is highly sensitive to fluctuations in air temperature. Global climate models (GCMs) project an increase in air temperatures for the Puget Sound region, and previous modeling within the Nooksack basin projects a reduction in snowpack extent through the 21st century and an increase in winter streamflow magnitude. As more landscape becomes exposed to rain rather than snow and heavy winter precipitation events intensify, peak flows and sediment delivery to streams will likely increase due to rapid runoff, resulting in salmon habitat degradation and increased flood risk. Thus, anticipating the effect of climate change on peak flows is crucial for salmon habitat restoration efforts and flood mitigation planning. To quantify the timing and magnitude of future peak flows, I use a calibrated Distributed Hydrology Soil Vegetation Model (DHSVM) and meteorological forcings from an ensemble of high-emission GCMs dynamically-downscaled using the Weather Research and Forecasting (WRF) model. Due to the variability of climate scenarios depicted by GCMs, a range of streamflow and snowpack magnitude changes in the Nooksack River basin are projected by the hydrology simulations. By the end of the 21st century, results indicate a decrease in annual peak snow-water equivalent (-72% to -82%), a shift in the timing of peak snow-water equivalent to approximately one month earlier, an increase in winter flows (+31% to +56%), a decrease in summer flows (-37% to -72%), and the disappearance of the snowmelt derived spring peak in the hydrograph as the basin transitions from transient to rain-dominant. These results are consistent with previous modeling in the Nooksack River basin and other regional climate change studies in the Pacific Northwest and Puget Sound region. Due to more precipitation falling as rain rather than snow and heavy rain events becoming more frequent and intense, future peak flows are projected to increase in magnitude by 34-60% across all flow durations and return periods that were analyzed, with the largest changes occurring in the high relief subbasins. The frequency of high magnitude, flood-inducing peak flows will also increase into the future, lengthening the flood season by approximately three months.

Author: Katharine A. Forbes
Publisher:
ISBN:
Category : Climatic changes
Languages : en
Pages : 0

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The current body of research in western North America indicates that water resources in the Oldman Basin are vulnerable to the impacts of climate change. The objectives of this thesis were to parameterize and verify the ACRU hydrological modelling system for the 256 km2 Beaver Creek watershed, a tributary to the Oldman River. The ACRU model successfully simulated monthly volumes of the observed hydrological record (r2 =0.78), and simulated the behaviour of the mean annual hydrograph with sufficient accuracy to assess the mean change in future hydrological response over 30-year simulation periods. A range of global climate model (GCM) projections were used to perturb the 1961-1990 baseline climate record using the delta downscaling technique, which resulted in the input for future hydrological simulations. Five potential future hydrological regimes were compared to the 1961-1990 baseline conditions to determine the net effect of climate change on the hydrological regime of the Beaver Creek catchment over three time periods of 2020, 2050 and 2080. Despite annual projections for a warmer and wetter climate in this region, the majority of the simulations indicated that the seasonal changes in climate resulted in a shift of the seasonal streamflow distribution. The results indicated an increase in winter and spring streamflow volumes and a reduction of summer and fall streamflow volumes over all time periods, relative to the baseline conditions (1961-1990) in 4 of the 5 scenarios.