Paul Whitfield

Paul H. Whitlield, Normand Rousseau&amp;amp;#x27;. and Eric Michnowskyz nland Waters. ... Nle... more Paul H. Whitlield, Normand Rousseau&amp;amp;#x27;. and Eric Michnowskyz nland Waters. ... Nleasurements of stleam pH and alkalinitv. and lain pH ancl acidit,v nere madc on site t&amp;amp;#x27;ithin 30 minutes of collection usini standard analvtical and QA/QC mcthods (Enrironment Canada 1979). ...

Linking Climate, Hydrology and Groundwater in High-Resolution Transient Groundwater Flow Models: a Case Study For a Climate Change Impacts Assessment in Grand Forks, BC

Agu Spring Meeting Abstracts, May 1, 2004

A case study of an unconfined aquifer in the Grand Forks valley in south-central BC was used to d... more A case study of an unconfined aquifer in the Grand Forks valley in south-central BC was used to develop methodology for linking climate models, hydrologic models, and groundwater models to investigate future impacts of climate change on groundwater resources. A three dimensional groundwater flow model of variable spatial resolution (constrained by borehole spacing) was implemented in MODFLOW, and calibrated to observation well data. Multiple scenarios of the hydraulic conductivity fields were used in a sensitivity analysis. A new methodology was developed for generating spatially-distributed and temporally-varying recharge zonation for the surficial aquifer, using GIS linked to the one-dimensional HELP (USEPA) hydrologic model that estimates aquifer recharge. The recharge model accounts for soil distribution, vadose zone depth and hydraulic conductivity, extent of impermeable areas, surficial geology, and vadose zone thickness. Production well pumping and irrigation return flow during the summer season were included in recharge computations. Although recharge was computed as monthly averages per climate scenario, it is driven by physically-based daily weather inputs generated by a stochastic weather generator and calibrated to local observed climate. Four year long climate scenarios were run, each representing one typical year in the present and future (2020s, 2050s, and 2080s), by perturbing the historical weather according to the downscaled CGCM1 general circulation model results (Environment Canada). CGCM1 model outputs were calibrated for local conditions during the downscaling procedure. These include absolute and relative changes in precipitation; including indirect measures of precipitation intensity, dry and wet spell lengths, temperature, and solar radiation for the evapotranspiration model. CGCM1 downscaling was also used to predict basin-scale runoff for the Kettle River upstream of Grand Forks. This river exerts strong control on the groundwater levels in the aquifer and physically-based discharge predictions were used in the transient groundwater flow model. Modeled discharge hydrographs were converted to river stage hydrographs at each of 123 river segments, and interpolated between known river channel cross-sections. Stage-discharge curves were estimated using the BRANCH model and calibrated to observed historical data. River channels were represented in three-dimensions using a high grid density (14 to 25 m) in MODFLOW, which were mapped onto river segments. River stage schedules along the 26 km long meandering channel were imported at varying, but high, temporal resolution (1 to 5 days) for every cell location independently. Head differences were computed at each time step for historical and future, mapped in GIS and linked to the MODFLOW model. Temporal changes in mass balance components show relations between pumping, storage, recharge, and flow. Within an annual cycle and between climate scenarios the results show different spatial and temporal distributions in groundwater conditions. Groundwater levels near the river floodplain are predicted to be lower earlier in the year under future climate scenarios, but away from rivers, groundwater levels increase slightly due to the predicted increase in recharge.

Introduction to Peatlands Special Issue: Improving Hydrological Prediction in Canadian Peatlands

Http Dx Doi Org 10 4296 Cwrj3404303, Jan 23, 2013

... 2007. Comparative study of suspended sediment concentrations downstream of harvested peat bog... more

A Canadian viewpoint on data, information and uncertainty in the context of prediction in ungauged basins

Hydrology Research, 2013

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Application Potential of Four Nontraditional Similarity Metrics in Hydrometeorology

Http Dx Doi Org 10 1175 Jhm D 13 0140 1, Sep 25, 2014

ABSTRACT This paper presents a review and assessment of four nontraditional similarity metrics th... more ABSTRACT This paper presents a review and assessment of four nontraditional similarity metrics that can be applied to hydrological and meteorological data. These metrics are 1) the uncentered correlation coefficient, 2) the Hodgkin–Richards index, 3) the Petke index, and 4) the Wang–Bovik index. The first metric has been widely used in hydrometeorology, and the other three have been proposed in other disciplines for similarity analysis. It is demonstrated that these similarity metrics, in their original formulations, either do not actually have the purported advantage over the traditional Pearson correlation coefficient or are not suitable for some hydrometeorological applications. They are reformulated in this study to address these deficiencies. The resulting modified metrics are unitless, bounded, and proportional to the Pearson correlation coefficient, and three of them have the confirmed advantage of explicitly penalizing for differences in the mean and/or in the variance. Two application examples are used to demonstrate the applicability of these similarity metrics in hydrometeorology. A metavalidation model and a graphical tool (Taylor diagram) are used to evaluate the performances of these similarity metrics. In a case study of analog analysis, the Wang–Bovik index stands out as the best metric for simulation of the human perception of similarity between two-dimensional patterns, whereas the modified Petke index and the traditional root-mean-square distance may perform slightly better than the others in the regions with a very large difference between the variances.