Department of Civil Engineering
University of Manitoba
 

Research Interests

The following materials are summaries from proposals that were awarded to Dr. Woodbury and collaborators.   These are Dr. Kenneth Snelgrove (Memorial) on the Assiniboine Delta Aquifer work below, Dr. Grant Ferguson (St. Francis Xavier)  on the Manitoba Hydro geothermal work, and Dr. James Hendry (Saskatchewan) on the South Okanagan project for the Canadian  Water Network (Dr. David Rudolph is the team leader).

Minimum relative entropy in surface and subsurface hydrology

The similarity between maximum entropy and minimum relative entropy (MRE) allows for recent advances by the author and co-workers in inverse theory to obviate some of the shortcomings of the former method. The advantages that MRE has over the PME are that the relative entropy measure is invariant under a coordinate transformation, prior probabilities are allowed, non-positive models are supported, and uncertainty in the model follows naturally and immediately. The purpose of the proposed NSERC research is to extend the theory and practice of MRE, with particular reference to (1) determination of synthetic unit hydrographs for small ungauged basins, (2) improved parameter estimation from L-moment and C-moment data, (3) derivation of surface infiltration relations from constraining moments, (4) seepage and unsaturated flow, (5) evaluation of data acquisition systems including estimation of missing data, (6) assessment of uncertainty in hydrologic models, such as land surface schemes, and (7) upscaling and downscaling of hydraulic conductivity. The unique aspect of the proposed research is that it integrates detailed field observations of the temporal and spatial variability of hydrologic parameters, with Bayesian/Maximum Entropy viewpoints of probabilities, and high-resolution numerical simulations. Research performed over previous NSERC funded periods has been highly successful and has led to a number of significant contributions in groundwater hydrology, and have found applications in a variety of scientific and engineering problems.

Drought Research Initiative:  Climate and Atmospheric Sciences

Global climate change is emerging as a major issue in the public and scientific minds in Canada. It is well known that many areas of North America have already experienced climate change impacts. For example, ground surface temperatures have increased, on average in Canada, by 0.8o C since predevelopment times. This deceptively small amount will have a major impact on future soil conditions and river flows. Computer-climate model predictions indicate that much of the North American central plains will likely become extremely variable in terms of weather. This will create huge problems, not only in the agricultural economy of Canada but in the ecosystems of our waterways and in our major groundwater aquifer systems.

This research addresses sustainability of water resources and agricultural practice in the Province of Manitoba. The project is being carried out by a team of researchers with expertise in several areas, namely groundwater modeling, surface water resources, geology, and economics. Bringing this multi-disciplinary team together to investigate, Manitoba’s water resources will lead to new and innovative solutions. More particularly the combination of groundwater models and land surface schemes has yet to be attempted anywhere in the world to investigate ground water resources under climate change scenarios. This will be ground breaking research. Also the interaction of engineering and economics will lead to cost effective solutions which may be more easily implemented as climate change become more acute.

  Low Temperature Geothermal Energy and the Environment

Geothermal energy is classified as a renewable-clean resource, along with solar, wind and biomass. The ultimate source of energy for geothermal systems is the enormous heat stored within and flowing through the earth. This is estimated at 40 million MW; an enormous number, although the ultimate potential for development is variable (Rybach, 2003). Most importantly, by using reasonable production rates and strategies, energy can be extracted and sustainable energy production can be achieved. Some of this energy is stored in  high temperature systems ( > 150 C), but the vast majority of energy is stored in low temperature (low-grade;  < 150 C) environs.  “Conventional” geothermal resources are exploited worldwide for electric generation by withdrawing fluid from deep reservoirs and specific geologic features, and extracting the heat content. There are many examples where this has been carried out in an environmentally sensitive and sustainable manner. In Canada, the focus has been on relatively low-temperature sources; those of the shallow subsurface at less than 100 C. The method of extraction is typically in the form of a heat pump and these are often referred to as geoexchange systems. 

Relatively little is known about the environmental impacts of heat pump systems, although it is  commonly assumed that impacts are negligible (Hunt, 2001).  Younger (2006, 2008) considered this topic at length and concluded that inadequate geoexchange design can lead to significant ecological and sustainability problems. Increasing geothermal development will require a greater degree of understanding of heat flow and groundwater flow in the subsurface.  Energy experts agree that in a few years time all large-sized building environmental controls will revolve around heat pump technology.  However, greater effort will be required in the design of individual systems and associated hydrogeological investigations to ensure that they are, in fact, environmentally sound and sustainable.  Although growing rapidly in Canada, installations are often based on experience and empirical know-how, and are far from optimized. Studies from Manitoba indicate that in many cases these systems are not sustainable or at least not sustainable at maximum efficiency (e.g. Ferguson and Woodbury, 2006). The operation of these systems must not only consider the viability of the thermal application itself, but also whether it is sustainable in an environmental sense. This can only be done by addressing possible impacts on physical hydrology and water quality in surrounding areas.

Understanding the sustainability and environmental issues revolving around low temperature geothermal energy represents the long-term objectives of my overall research program.   I intend to move forward along the same direction as recommended in a recent  MIT report (Tester, 2006),  namely to help provide an evaluation of geothermal energy as a major supplier of  energy in Canada. The concentration of my research though, will be on the use of geothermal energy in direct-use applications rather than electricity generation.

My goal over this next phase of research is to investigate the thermal, environmental and geotechnical characteristics and properties of ground (soil, geology, aquifers, etc.), which may be needed to develop better construction and monitoring methods, and for a greater understanding of  hydrogeology and heat flow.  This work will be vital to prioritize the important scientific issues and further refine societal and regulatory needs so that the groundwater and geo-exchange communities can work together  for continued growth in this sector.  



Canadian Water Network :  Assessment of Regional Water Resource Impacts from Agriculture

The water research community in Canada is large and multidisciplinary, and includes numerous pockets of internationally recognized excellence. The community is diffuse however, and in the absence of a national vision tends to respond to the needs and situations of particular stakeholders or to react to local and regional issues. While many issues are indeed of a local scale, it is also true that there are many interdisciplinary problems of national scale. If we are to address these problems effectively, and if Canada is to assert herself in international markets, then it is essential that greater cohesion and greater communication within and between disciplines be developed. If this can be accomplished by the Network, then the more tangible benefits such as improved water management and public health, technology development and wealth creation will readily follow.

The Assiniboine Delta Aquifer (ADA) is a large, unconfined sand and gravel aquifer system located in the south west of Manitoba. The ADA area supports extensive potato farming. Irrigation water is derived from the ADA and the cropping practices require extensive use of fertilizers. The ADA system is also heavily relied on as a drinking water source and the impacts of the agricultural operations on the ADA are of considerable concern to the Province. Significant subsurface data are available on geologic structure and hydraulic characterization. Long-term implications of the agricultural activities combined with anticipated variations in precipitation patterns due to climate change will be investigated through the application of innovative regional modeling approaches. Specifically, a tightly coupled land surface scheme (LSS) and groundwater model will be developed.

Coupling of these models will be required to simultaneously simulate the impacts of irrigation/recharge on both surface water and groundwater. Impacts that will be addressed include: i) alteration of groundwater recharge and nitrate loadings due to irrigation and changes to the frozen/unfrozen distributions affecting spring infiltration of snowmelt, ii) determination of low stream flows, iii) surface soil moisture prediction necessary to implement advanced irrigation management, and iv) well drawdown profiles, necessary for determination of pumping cost and long-term aquifer capacity. Socio-economic analysis will also be used to examine alternative groundwater extraction strategies such as short-term reallocation of water from lower valued to higher valued uses to reduce stresses placed on the aquifer by agricultural practices. Adaptive scenarios including site-specific BMPs will be evaluated in consultation with current user groups from a social perspective using the coupled Model.





Dr. Allan Woodbury