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Browsing Centre for Hydrology Reports by Subject "Cold Regions Hydrological Model"
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Item Development of a Snowmelt Runoff Model for the Lower Smoky River(Centre for Hydrology, University of Saskatchewan, Saskatoon, Saskatchewan, 2013) Pomeroy, John W.; Shook, Kevin; Fang, Xing; Brown, Tom; Marsh, ChristopherThe Smoky River tributary of the Peace River has an ungauged (in real-time) basin area of 23,769 km2, corresponding to 46% of its basin area of 51,839 km2 . The purpose of this study was to develop a model to simulate the daily spring ungauged flows of the Smoky River and its main tributary, the Little Smoky River for recent periods using measured meteorological data and forecast periods using the outputs of a numerical weather forecast model. A physically-based model of the ungauged local flows contributing to the Smoky River at Watino and the Little Smoky River at Guy, the Lower Smoky River Model (LSRM), was developed using the CRHM platform. The model was deployed to 26 ungauged sub-basins, from which discharges were routed and accumulated to produce the ungauged discharges at Guy and Watino. The LSRM modelled discharge was evaluated to estimate the discharge of the Smoky River and Little Smoky River in an operational setting with measured meteorological observations. Results from this comparison were very good with a high degree of hydrograph predictability, small bias in flow estimation, and very good prediction of peak daily discharge and excellent prediction of the timing of peak daily discharge. The results were somewhat better for the Smoky River than for the Little Smoky River, showing the effect of increasing basin size in compensating for inadequate precipitation observation density and/or errors in model structure or parameterization. The model has not yet been tested in an operational setting during a spring snowmelt event and its full capabilities and usefulness cannot be assessed until it has been tested in such a setting.Item Improving and Testing the Prairie Hydrological Model at Smith Creek Research Basin(Centre for Hydrology, University of Saskatchewan, Saskatoon, Saskatchewan, 2014) Pomeroy, John W.; Shook, Kevin; Fang, Xing; Dumanski, Stacey; Westbrook, Cherie; Brown, TomThe 2010 Prairie Hydrological Model configuration of the Cold Regions Hydrological Model was developed to include improved snowmelt and evaporation physics and a hysteretic relationship between wetland storage and runoff contributing area. The revised model was used to simulate the snow regimes on and the streamflow runoff from the five sub-basins and main basin of Smith Creek, Saskatchewan for six years (2007-2013) with good performance when compared to field observations. Smith Creek measured streamflows over this period included the highest annual flow volume on record (2011) and high flows from heavy summer rains in 2012. Smith Creek basin has undergone substantial drainage from 1958 when it contained 96 km2 of wetlands covering 24% of the basin area to the existing (2008 measurement) 43 km2 covering 11% of the basin. The Prairie Hydrological Model was run over the 2007-2013 period for various wetland extent scenarios that included the 1958 historical maximum, measured extents in 2000 and 2008, a minimum extent that excluded drainage of conservation lands and an extreme minimum extent involving complete drainage of all wetlands in Smith Creek basin. Overall, Smith Creek total flow volumes over six years increase 55% due to drainage of wetlands from the current (2008) state, and decrease 26% with restoration to the 1958 state. This sensitivity in flow volume to wetland change is crucially important for the water balance of downstream water bodies such as Lake Winnipeg. Whilst the greatest proportional impacts on the peak daily flows are for dry years, substantial impacts on the peak daily discharge of record (2011) from wetland drainage (+78%) or restoration (-32%) are notable and important for infrastructure in and downstream of Smith Creek. For the flood of record (2011), the annual flow volume and the peak daily discharge are estimated to increase from 57,317 to 81,227 dam3 and from 19.5 to 27.5 m3 /s, respectively, due to wetland drainage that has already occurred in Smith Creek. Although Smith Creek is already heavily drained and its streamflows have been impacted, the annual flow volumes and peak daily discharge for the flood of record can still be strongly increased by complete drainage from the 2008 wetland state, rising to 103,669 dam3 and 49 m3 /s respectively. This model simulation exercise shows that wetland drainage can increase annual and peak daily flows substantially, and that notable increases to estimates of the annual volume and peak daily flow of the flood of record have derived from wetland drainage and will proceed with further wetland drainage.Item Informing the Vermilion River Watershed Plan through Application of the Cold Regions Hydrological Model Platform(Centre for Hydrology, University of Saskatchewan, Saskatoon, Saskatchewan, 2012) Pomeroy, John W.; Fang, Xing; Shook, Kevin; Westbrook, Cherie; Brown, TomThe Vermilion River Basin has been identified as one of most altered basins in the North Saskatchewan River Basin by the North Saskatchewan Watershed Alliance. Of all the basin altering activities, wetland drainage is thought to be the most important one in impacting watershed hydrology. The Cold Regions Hydrological Model (CRHM) has had recent developments that make it particularly appropriate to evaluate the impacts of Canadian Prairie wetlands on hydrology. In light of the importance of wetlands in the Vermilion River Basin and the capability of CRHM, this study had five objectives: 1) Setup CRHM for the Vermilion River Basin and conduct preliminary tests using local meteorological data. 2) Develop an improved wetland module that incorporates the dynamics of drained wetland complexes in the physically based, modular Prairie Hydrological Model of CRHM. 3) Refine CRHM results using advances in the improved wetland module, additional parameter data and other adjustments as necessary. 4) Demonstrate scenarios/sensitivity of landscape components such as wetlands and uplands to support planning decisions and make recommendations for land and watershed management. 5) Apply CRHM results to fortify recommendations and support decision making during initial plan implementation. The objectives were addressed with the following methodology. Existing data on precipitation, hydrometeorology, wetland characteristics, stage and extent, drainage pattern and land cover in the Vermilion River Basin were compiled. The existing CRHM Prairie Hydrological Model formulation was set up on the basin and test runs conducted and compared to streamflow hydrographs over multiple years. Then, improvements to the Prairie Hydrological Model formulation of CRHM were made so that CRHM could simulate sequences of many wetlands of varying sizes. The improved model was evaluated through hydrological simulation and quantitative analysis of streamflow and then used in sensitivity analysis of the effect of changing wetland drainage/restoration on streamflow for the Vermilion River. The model was then used to evaluate wetland manipulation and climate scenarios to fortify recommendations, explore options and support decision making for the implementation of the Vermilion watershed plan. The streamflow response of the Vermilion River Basin at its mouth was found to be dominated by channel hydraulics and the control structures in the lower basin and so it is influenced by wetlands only to the extent that the management regime of these control structures is affected by upstream hydrological behaviour of the tributaries with respect to volume and timing of streamflow inputs to the structures. Changes in the upper basin streamflows are more likely to be controlled by changes in the basin hydrological processes rather than in-stream water management and/or channel modifications and therefore the upper basin streamflows are more likely to show the effects of the manipulation of wetland storage.Item Sensitivity of Snowmelt Hydrology on Mountain Slopes to Forest Cover Disturbance(Centre for Hydrology, University of Saskatchewan, Saskatoon, Saskatchewan, 2011) Pomeroy, John W.; Fang, Xing; Ellis, Chad; Guan, MayMarmot Creek Research Basin was the subject of intense studies of snowmelt, water balance and streamflow generation in order to generate a five year database of precipitation inputs, snowpack dynamics and streamflow that could be used in hydrological model testing. A physically based hydrological model of the basin was constructed using the Cold Regions Hydrological Model and tested over four years of simulation. The model was found to accurately simulate snowpacks in forested and cleared landscapes and the timing and quantity of streamflow over the basin. The model was manipulated to simulate the impacts of forest disturbance on basin snow dynamics, snowmelt, streamflow and groundwater recharge. A total of 40 forest disturbance scenarios were compared to the current land use over the four simulation years. Disturbance scenarios ranged from the impact of pine beetle kill of lodgepole pine to clearing of north or south facing slopes, forest fire and salvage logging impacts. Pine beetle impacts were small in all cases with increases in snowmelt of less than 10% and of streamflow and groundwater recharge of less than 2%. This is due to only 15% of the basin area being covered with lodgepole pine and this pine being at lower elevations which received much lower snowfall and rainfall than did higher elevations and so generated much less streamflow and groundwater recharge. Forest disturbance due to fire and clearing affected much large areas of the basin and higher elevations and were generally more than twice as effective in increasing snowmelt or streamflow. For complete forest cover removal with salvage logging a 45% increase in snowmelt was simulated, however this only translated into a 5% increase in spring and summer streamflow and a 7% increase in groundwater recharge. Forest fire with retention of standing burned trunks was the most effect forest cover treatment for increasing streamflow (up to 8%) due to minimizing both sublimation of winter snow and summer evaporation rates. Peak daily streamflow discharges responded more strongly to forest cover decrease than did seasonal streamflow with increases of over 20% in peak streamflow with removal of forest cover. It is suggested that the dysynchronization of snowmelt timing with forest cover removal resulted in an ineffective translation of changes in snowmelt quantity to streamflow. This resulted in a complementary increase in groundwater recharge as well as streamflow as forest cover was reduced. Presumably, a basin with differing soil characteristics, groundwater regime or topographic orientation would provide a differing hydrological response to forest cover change and the sensitivity of these changes to basin characterisation needs further examination.Item Wolf Creek Cold Regions Model Set-up, Parameterisation and Modelling Summary(Centre for Hydrology, University of Saskatchewan, Saskatoon, Saskatchewan and State Hydrological Institute, Saint Petersburg, Russia, 2010) Pomeroy, John W.; Semenova, Olga M.; Fang, Xing; Vinogradov, Yuri B.; Ellis, Chad; Vinogradova, Tatyana A.; MacDonald, Matt; Fisher, Elena E.; Dornes, Pablo; Lebedeva, Ludmila; Brown, TomWolf Creek Research Basin is in the Upper Yukon River Basin near Whitehorse, Yukon and is representative of headwaters in the northern Coast Mountains. It was established in 1993 to better develop northern hydrological models, and related hydrological process, ecosystem and climate science. Yukon Environment maintains Wolf Creek hydrometeorological and hydrometric stations and conducts regular snow surveys in the basin. A number of hydrological models have been tested on Wolf Creek and all have had great difficulty in simulating the cold regions hydrological processes that dominate its streamflow response to snowmelt and rainfall events. Developments in understanding hydrological processes and their interaction with terrestrial ecosystems and climate at Wolf Creek have lead to the development of the Cold Regions Hydrological Model (CRHM) by a consortium of scientists led by the University of Saskatchewan and Environment Canada. CRHM comprehensively incorporates the blowing snow, intercepted snow, sublimation, melt energetics, infiltration to frozen soils, organic terrain runoff and other cold regions hydrological phenomenon and discretizes the catchment on a hydrological response unit basis for applying water and energy balance calculations. The model is intended for prediction of ungauged basins with parameter selection from physically measurable properties of the river basin or regional transference of calibrated values. In Russia, a long tradition of cold regions hydrological research has led to the development of the Hydrograph model by the State Hydrological Institute, St. Petersburg. The Hydrograph model contains several promising innovations regarding the formation and routing of runoff, discretizes the basin using hydrological response units and addresses some (but not all) cold regions hydrological processes. Hydrograph parameter selection is made from both physically measured properties and those that are calibrated, but the calibrations can be easily regionalized. Test simulations of runoff processes using CRHM and Hydrograph for Wolf Creek Research Basin was undertaken using data archives that had been assembled and cleaned up in a related project by the University of Saskatchewan. The test simulations are a demonstration of model capabilities and a way to gain familiarity with the basin, its characteristics and data and to better compare model features. Data available included a GIS database of basin characteristics (topography and vegetation distribution) and the hydrometeorological and hydrometric observational dataset from Yukon Environment. The sub-surface hydrology presented a formidable unknown in parameterising the model. Hydrograph performed well in initial simulations of the basin hydrograph for multi-year runs. Several issues with observational data quality created substantial uncertainty in evaluating the model runs.