Daniel Caissie

Modelling of maximum daily water temperatures in a small stream using air temperatures

Maximum daily stream water temperature information is very important when assessing fish habitat in terms of distribution and fish growth rate. For instance, coldwater fishes such as the Atlantic salmon can be adversely affected by these maximum summer temperatures or by those exacerbated by land use practices such as deforestation. The present study deals with the modelling of maximum daily stream water temperatures using regression and stochastic models to relate air and water temperatures in Catamaran Brook, a small stream in New Brunswick where long-term multidisciplinary habitat research is being carried out. The regression model was a logistic type function while the stochastic model was based on the autocorrelation structure of the water temperature time series. The first step in the stochastic modelling was to establish the long-term annual component in stream water temperatures. This was possible by fitting a combination of a Fourier and Sine function to stream water temperatures. The short-term residual temperatures (departure from the long-term annual component) were modelled using a second order Markov process. Results showed that the regression type model was only possible on a weekly basis with a root-mean-square error (RMSE) of 1.93°C. Alternatively, the stochastic model showed that it was possible to predict maximum daily water temperatures for small streams using air temperatures only. The RMSE varied between 1.48 and 1.62°C on an annual basis from 1992 to 1997, which were lower than the regression model. Calibrations were carried out on a seasonal basis as well as during the summer of each year. However, the improvements in the modelling were less than 0.1°C. It was also noted that the empirical coefficient linking air to water temperatures residuals varied on a seasonal and summer basis, and this coefficient was related to summer discharge. Although variable, this empirical coefficient did not improve the modelling significantly on a seasonal or summer basis.

A Review of Statistical Water Temperature Models

The use of statistical models to simulate or to predict stream water temperature is becoming an increasingly important tool in water resources and aquatic habitat management. This article provides an overview of the existing statistical water temperature models. Different models have been developed and used to analyze water temperature-environmental variables relationship. These are grouped into two major categories: deterministic and statistical/stochastic models. Generally, deterministic models require numerous input data (e.g., depth, amount of shading, wind velocity). Hence, they are more appropriate for analyzing different impact scenarios due to anthropogenic effects (e.g., presence of reservoirs, thermal pollution and deforestation). In contrast to the deterministic models, the main advantage of the statistical models is their relative simplicity and relative minimal data requirement. Parametric models such as linear and non-linear regression are popular methods often used for shorter time scales (e.g., daily, weekly). Ridge regression presents an advantage when the independent variables are highly correlated. The periodic models present advantages in dealing with seasonality that often exists in periodic time series. Non-parametric models (e.g., k-nearest neighbours, artificial neural networks) are better suited for analysis of nonlinear relationships between water temperature and environmental variables. Finally, advantages and disadvantages of existing models and studies are discussed.

VARIATION IN STREAM WATER CHEMISTRY AND HYDROGRAPH SEPARATION IN A SMALL DRAINAGE BASIN

In the present study, the change in chemical composition of stream water was investigated for a small Atlantic salmon stream (Catamaran Brook) of the Miramichi River system in New Brunswick, Canada. Chemical composition of runoff and groundwater flow was established, as were relations between concentration of dissolved materials and discharge. Specific storm events were analysed to determine changes in chemistry and to carry out a hydrograph separation using specific chemical parameters. The hydrograph separation was used to identify the relative contribution of groundwater flow to total streamflow. By selective sampling of stream water during high flow (runoff) and low flow (groundwater) periods it was possible to observe the range in chemical composition of many parameters in Catamaran Brook. Most relationships between concentration of chemical parameters and discharge were significant at P < 0.0001, with sodium having the highest coefficient of determination (r2 = 0.849). Concentration returned to pre-storm levels in approximately 10 days following an event. As observed in previous studies, the peak groundwater flow plays an important role during the storm hydrograph and can account for as much as 91 % of the total peak flow for small events. For higher flow events in Catamaran Brook, the groundwater flow contribution was markedly lower (55% of total streamflow). The composite hydrograph separation revealed that conductivity, as a single parameter, provided the best results in representing the composite separation.

Comparison of streamflow between pre and post timber harvesting in Catamaran Brook (Canada)

Abstract The forest industry plays a major role in the economy of eastern Canada. The recreational fishery also represents an important source of revenue for this area. Therefore, there is concern over the potential economic effects and ecological impacts from logging operations on aquatic habitats. The present study deals with the comparison of streamflow between pre and post timber harvesting at Catamaran Brook (New Brunswick, Canada) to identify any potential changes to the hydrological regime. Studies were carried out on two sub-basins of Catamaran Brook, namely the Middle Reach (mid-basin) and the Upper Tributary 1. The harvested area at the Middle Reach represented 2.3% of this sub-basin while 23.4% of Upper Tributary 1 was harvested. It was noted that during both the calibration and timber harvesting phases, meteorological conditions (e.g. precipitation, runoff) contributed to relatively high natural variability. When studying changes on an annual and seasonal basis for the basin cut at 2.3% (i.e. Middle Reach) and using a control basin for comparison, no changes were detected to the annual water yield, seasonal runoff and streamflow timing between the calibration and timber harvesting phases. On a summer rainfall event basis, no changes were detected at the Middle Reach and the Upper Tributary 1 when studying relations between precipitation and stormflow (obtained through hydrograph separation). Alternatively, changes were detected in relations between peak flows and precipitation ( p When comparative studies were carried out on peak flow and stormflow between sub-basins (using the Middle Reach as control for treatments vs. the most affected site, i.e. Upper Tributary 1), significant changes were detected in peak flow ( p

The Processes, Patterns and Impacts of Low Flows Across Canada

This paper provides an overview of low flow characteristics for six regions of Canada: the Arctic; the Mountains; the Prairies; southern Ontario; the Canadian Shield and the Atlantic. Processes that influence low flows are contrasted between the six regions examined. Data from a common analysis period for 51 gauging stations are used to evaluate flow duration curves and to explore the relationship between low flows and drainage area. The results reveal a diversity of processes influencing low flows and illustrate important regional differences in low flow characteristics and the impacts associated with low flows.

Flood processes in Canada: Regional and special aspects

This paper provides an overview of the key processes that generate floods in Canada, and a context for the other papers in this special issue – papers that provide detailed examinations of specific floods and flood-generating processes. The historical context of flooding in Canada is outlined, followed by a summary of regional aspects of floods in Canada and descriptions of the processes that generate floods in these regions, including floods generated by snowmelt, rain-on-snow and rainfall. Some flood processes that are particularly relevant, or which have been less well studied in Canada, are described: groundwater, storm surges, ice-jams and urban flooding. The issue of climate change-related trends in floods in Canada is examined, and suggested research needs regarding flood-generating processes are identified.

Instream Flow Assessment: From Holistic Approaches to Habitat Modelling

The conflict between the ever-increasing demand for river water (hydroelectric development, irrigation, drinking water, etc.) and the environmental need for sustaining flows during drought and low flow periods is a recurring problem in water resource management. Competition between water abstraction (offstream use) and instream flow needs (minimum flow for the protection of fish habitat) will undoubtedly increase in the future, as it is estimated that worldwide more than 50% of total accessible runoff is presently being used. Instream flow methods are the primary and essential tools used during environmental impact assessments to evaluate the level of aquatic habitat protection for rivers under reduced flow conditions. Since the 1970s, methodologies, applicable to various scopes of water utilization and of a range of sophistication, have been developed. These can be classified into three categories: historical streamflow, river hydraulics and habitat preference methods. New methods are widely used in North America, but important questions related to validation and range of applicability remain. Existing and new instream flow methods also need to take into consideration changing environmental conditions such as climate change, in establishing a level of protection. The research reported here focuses on the current knowledge, strengths and weaknesses of a variety of instream flow methods as well as their associated level of aquatic habitat protection. Recommendations are provided for future instream flow research depending on the range of complexity of applied methods being contemplated.

Hydrometeorological Trends in the Miramichi River, Canada: Implications for Atlantic Salmon Growth

Abstract Hydrometeorological conditions are important determinants of the distribution and productivity of Atlantic salmon Salmo salar in freshwater habitats. Environmental conditions, such as temperature, precipitation, and streamflow, affect an aquatic organisms growth rate, developmental rate, behavior, and ultimate survival. In the Miramichi River, New Brunswick, Canada, climatic and hydrological conditions have been monitored for over 30 years, providing a unique opportunity to examine long-term changes in temperature, precipitation, and streamflow and their effects on juvenile Atlantic salmon. Average air temperature in the Miramichi region increased over time, particularly in spring and summer months. Coincident changes in water temperature were not observed, with only summer water temperature increasing in the Southwest Miramichi River. Extreme summer water temperatures in the Southwest Miramichi River regularly exceeded the upper temperature threshold for growth of Atlantic salmon (22.5°C). Few ...

Multivariate analysis of the low-flow regimes in eastern Canadian rivers

Abstract A characterization of the low-flow regimes of 175 eastern Canadian rivers based on multivariate analysis of hydrological indices (HIs) is presented. Principal component analysis (PCA) was used to identify eight highly informative and low-correlated HIs amongst 67 low-flow HIs reported in the literature, and to test their ability to describe regional characteristics and differences among low-flow regimes at the 175 stations. It was found that eight HIs can provide a regional description of the main low-flow characteristics almost equivalent to using all HIs related to low flows. The PCA also identified regional similarities and differences among the geographical and hydrological regions within the Province of Quebec, as well as between the Atlantic provinces of Canada. Multivariate analysis proved to be an efficient tool that can complement expert knowledge in the selection of criteria for instream flow assessments in eastern Canada, by quantitatively indicating indices carrying high information, and by ensuring low redundancy in the selected subset of variables (HIs). Citation Daigle, A.,St-Hilaire, A., Beveridge, D., Caissie, D. & Benyahya, L. (2011) Multivariate analysis of the low-flow regimes in eastern Canadian rivers. Hydrol. Sci. J. 56(1), 51–67.

An Evaluation of Mitigation Measures to Reduce Impacts of Peat Harvesting on the Aquatic Habitat of the East Branch Portage River, New Brunswick, Canada

The evaluation of impacts of peat harvesting on riverine ecosystems is essential to the implementation of adequate mitigation measures. The objective of the present study was to determine the potential impacts of peat harvesting on the physical (e.g., flow, suspended sediment concentration (SSC), water temperature) and biological (fish abundance) parameters of the East Branch Portage River, New Brunswick. This study was initiated in 2005 and a before and after study design was used to assess impacts. When the operational activities were initiated (spring 2007), 19 ha of peatland (15% of the total area scheduled for harvesting) was drained. The exploited area was drained through a network of ditches which emptied into a sedimentation pond. Drained water subsequently flowed into a 250 m vegetated buffer zone and discharged into the East Branch Portage River. Drained water did not diffuse throughout the buffer zone as expected. Rather, water tended to concentrate in a natural depression (channel) in the buffer zone, thus connecting the outflow of the sedimentation pond directly to the river. Two main results deserve attention. First, elevated SSC events were recorded in the East Branch Portage River downstream of the confluence of the channel formed in the buffer zone and the river. Periods of elevated SSC could be attributed to poor maintenance of the sedimentation pond. However, elevated SSC events were also recorded after pond maintenance and were concurrent with the timing of ditching activities within the peatland. Secondly, fish abundance was lower in 2007 compared to 2006 (pre-development period). However, potential impacts of peatland development on fish abundance should be interpreted with caution at this stage of the study.