Dr David Rudolph provides a brief history of hydrogeology, a field which is intrinsically linked to his work on groundwater and surface water resources, and his plan to develop sustainable, regional-scale water management systems

Since you began your career, how has the existing knowledge base expanded?

My specific field is hydrogeology, which focuses on the subsurface component of the hydrologic cycle. This field concentrated on groundwater resource development until the early 1970s when the focus began to include groundwater contamination, its sources, impacts and implications for drinking water systems.

How has the field of hydrogeology progressed in recent years?

During the 1970s, 80s and 90s, the investigation of groundwater contamination increased and indeed dominated the field. In the 1990s and 2000s considerable effort was placed on remediation of groundwater contamination problems, mostly related to local or point sources of contamination.

Over the last decade, there has been a growing emphasis on groundwater quantity issues related to sustainability of municipal aquifer systems and the influence of groundwater development on the health of aquatic ecosystems (streams and wetlands). Numerical modelling tools have improved substantially

and are used for analysis. The long-term management of the combined groundwater and surface water resources is a major topic of research considering the impact of legacy land use practices, future development and the influence of climate change on sustainability of the groundwater resource.

How do transport characteristics of parent material affect water supplies?

The geologic characteristics of the subsurface represent one of the three key factors that influence groundwater flow and control contaminant mobility. The other two factors relate to the nature of the contaminant species and the hydrologic conditions that drive the interaction between surface water and groundwater, and control subsurface water movement. The parent material properties are highly variable spatially but, other than the very near surface, change very little with time. The hydrologic conditions are highly transient. The more permeable the parent material, the more rapidly groundwater will flow under similar hydrologic drivers. Parent materials vary greatly in how they interact with different contaminate species, ranging from almost completely conservative or non-interactive, to highly reactive and sorptive, which can influence both the chemical composition of the contaminant species and the rate at which it moves through the subsurface.

Could you highlight the single greatest challenge facing the regional hydrological system?

The greatest challenge in many components of hydrology, including hydrogeology, is the measurement of physical characteristics and natural hydrologic phenomena that are critical to understanding the behaviour of the hydrologic (water) cycle at the regional or watershed scale. The diversity of geologic conditions, climatic patterns, land use practices and datasets required to permit predictive assessment of hydrologic response is immense.

Data collection networks, sensors and communication systems that will link remote locations and permit the collection of a wide range of critical parameters are still under development and are in need of continued advancement to provide the information required to inform regional scale hydrologic challenges, such as those listed above.

Based upon the science, what advice would you give to those looking to protect against future water supply vulnerability?

The conditions leading to an increased threat from enhanced recharge, associated with rapid snow melts and intense precipitation, can be recognised in the field and measures taken to redirect surface runoff streams or, at the very least, raise awareness of how these extreme recharge events can increase well contamination risk, especially from pathogens. We need to recognise and take steps to protect against these conditions through treatment options or temporary termination of the supply. This is playing a major role in the development of new regulations that control the designation of public drinking water wells in terms of their status as groundwater under the direct influence of surface water (GUDI) designation. In Ontario, this regulation is being reconstructed to take into account the influence of extreme climatic conditions.

What more is needed to extend our knowledge of hydrologic events and the hydrologic cycle?

The influence of extreme hydrologic events on the dynamics of the hydrologic cycle is still very poorly understood and in need of additional research. This involves a multidisciplinary approach and is directly related to both the health of the ecosystem, including the aquatic environment, and to human health through the impact of the quality and quantity of groundwater drinking supplies. This is another component of the overall impact of climate change.

Making hydrological headway

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Dr D

avID

rUD

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HigHly inteRDiSCiplinaRy in nature, because of the crucial role water plays in both human health and natural ecosystems, hydrogeology brings together numerous specialists to solve issues pertaining to water resources. In groundwater systems, complex interactions govern the transport of water above and below ground. a combination of chemical, physical and biological processes determine the occurrence, distribution and movement of groundwater contaminants but it is only in recent years that we have begun to reveal how each element interacts.

Groundwater recharge occurs when rain water, snow melt (precipitation) or surface water infiltrates and transmits through the soil profile, past sand grains, sediment pores and fractured rock to replenish the storage of subsurface waters. This percolated water remains within a vast natural underground storage system until drawn back up by capillary action, natural discharge or human water extraction. hydrogeologists can help locate reserves of groundwater and assess their capacity to provide sustainable source waters for a wide range of natural and anthropogenic uses. Their skills are used to assist in land use planning and in researching approaches for sustainable groundwater management.

gRounDWateR in CanaDa

approximately 30 per cent of the canadian population depends on groundwater for domestic use. Two-thirds of users are situated in rural areas and use wells to retrieve water. In recent years, canada has seen an increase in the incidence

of extreme hydrologic events, many of which are affecting groundwater quantity and quality. according to health canada, more than 160 waterborne disease outbreaks were reported in canada between 1974 and 1996 although it is estimated that only one-tenth of such outbreaks are even recorded. This has raised public concern about the importance and fragility of this resource.

One particular example has been noted by Dr David rudolph, a Professor at the Department of earth and environmental sciences, University of Waterloo, Ontario. During May 2000, in Walkerton, Ontario, an extreme rain storm transported cattle manure into the town’s wells, contaminating the water with E. coli and Campylobacter jejuni bacteria. The results were shocking; seven people died and more than 2,300 people became ill. Unfortunately evidence showed that the outbreak could have been prevented by using continuous chlorine residual and turbidity monitors. The outbreak emphasised the need for more sustainable and accurate methods of managing and preserving groundwater.

gRounDWateR aSSeSSment

events like Walkerton prompted scientists to better explore the sustainability and security of groundwater in canada. This is certainly the case for rudolph, whose research has contributed extensively to the field.

In a recent study, published in the Journal of contaminant hydrology, rudolph investigates the ‘Influence of macroporosity on preferential solute and colloid transport in unsaturated field soils,’ to assess the vulnerability of shallow water to contamination from surface sources. conducted using two field sites in Ontario, rudolph and his team examined the influence of macroporous soils, as well as the depth and movement of dissolved and colloid tracers that occurred after major infiltration events. They analysed the depths of dye and microspheres in the soil, observing that it was highly likely that surface-applied contaminants could reach shallow water tables during extreme hydrologic events. rudolph concluded that further understanding of macropore flow behaviour could help prevent contamination of public water resources.

rudolph is also monitoring extreme hydrologic events and their affects on groundwater, developing new models to generate meaningful three-dimensional frameworks. he hopes to assess hydrologic drivers so his team can better understand how they influence groundwater vulnerability and sporadic increases in contamination risk. The

Groundwater managementWith nearly one third of canadians dependant on groundwater, a scientist from the university of Waterloo, ontario, assesses groundwater vulnerability to improve groundwater management strategies and help conserve this finite resource

Dr DavID rUDOlPh

80 inteRnational INNOvaTION

effects of transient hydrologic phenomena on groundwater susceptibility and recharge is an area of investigation that has been rarely accounted for, however this process may hold the key to critical controlling parameters. The team also hopes that their research will contribute to the improvement of public health and contamination protection policy, as well as mitigation strategies.

ClimatiC impaCtS

climate change has been linked to several negative impacts on groundwater. excessive floods caused by intensified weather conditions, for instance, lead to increased surface runoff and reduce groundwater recharge. On the other hand, ephemeral flow events can cause surface sources of contamination to be absorbed into the subsurface through accelerated recharge, particularly in agricultural landscapes, threatening water quality and potentially public health. equally devastating, droughts cause the land to dry up and can lead to severe damage to both above and below ground ecosystem health. In many dry regions of the world, soil salinity is also becoming a problem due to brackish groundwater seeping up the soil profile.

rudolph has been focused on large-scale precipitation and mid-winter snow melt periods, finding that the combination of warmer and shorter winters can impact heavily on snow pack and spring melt water volumes , in turn, preventing full replenishment of the hydrological cycle during the spring freshet (increased surface flows resulting from snow melt). The formation of ephemeral waters during mid-winter melts and intensive bouts of precipitation can result in short-lived, yet intense local recharge events, a phenomenon that is a major component of rudolph’s research.

rudolph warns that, “during the formation of temporary surface water bodies, downward mobility of contaminants such as pathogens can occur in short, event-based time periods, which can significantly increase the threat to drinking water supplies from microbial contamination”. It is for this reason that he hopes to support developments for better groundwater management.

SoutHeRn ontaRio WateR ConSoRtium

In addition to his many reputable contributions to the field of hydrogeology, rudolph was also

one of the founders of the southern Ontario Water consortium (sOWc) – a caD $50 million collaborative organisation designed to facilitate water-related innovations and support their progression to the commercial market. The consortium is composed of eight universities, as well as several industrial, municipal and non-profit partners and volunteers. The University of Waterloo’s Water Institute also supports research and development activities at sOWc.

Developed in august 2011, sOWc aims to build an integrated research platform and to develop, test and demonstrate water and wastewater technologies and services. Their novel watershed monitoring systems, contamination, drinking and wastewater treatments, sensor technologies, assessment strategies and equipment has been highly praised. In addition, sOWc’s creation of unique, ‘smart’ technologies to record the information needed to assess and quantify extreme hydrological events is a core focal point in rudolph’s endeavours.

moDelling pRoCeSS

researchers who are part of the canadian Water Network (cWN), a nation-wide federally funded consortium of universities involved in water research, have been monitoring the effects of climate change on groundwater through seasonal climatic and extreme hydrologic events with emerging models to measure recharge and yearly contaminant mass flux. rudolph leads one of the teams focused on sustainable water management in the agricultural landscape. “Field evidence clearly illustrates that surface waters infiltrate rapidly and deeply beneath these ephemeral streams carrying surface source contaminants and potentially increasing source water vulnerability.” The results show reduced travel time from ground surface to water wells and correlate with an increased risk to water quality.

rudolph hopes that a clear understanding of the major influencing factors on regional aquifer systems and municipal supply wells will allow for greater progress in groundwater protection. he is optimistic that his work can support the development of effective land management policy, including water protection strategies, to ultimately improve water quality and agricultural practices for the ever-expanding global population and increasingly vulnerable climatic system.

inCoRpoRating SeaSonal anD extReme HyDRologiC eventS into gRounDWateR ReCHaRge anD vulneRaBility aSSeSSment

oBJeCtiveS

• To investigate and quantify the impact of seasonal hydrologic variability on estimates of regional groundwater recharge and source vulnerability assessment

• To collect dense, integrated data sets designed to permit the quantification of recharge and contaminant mass flux throughout the course of the annual climatic cycle incorporating numerical analysis using emerging models

• To provide authorities with the tools to develop long-term groundwater management and source protection plans and establish science-based policies governing land use management related to emerging groundwater protection legislation

Key CollaBoRatoRS

Dr edwin Cey, Dr Cathy Ryan, University of Calgary, Alberta • Dr Jim Hendry, University of Saskatchewan, Saskatchewan • Dr al Woodbury, University of Manitoba, Manitoba • Dr Brewster Conant, Dr neil thomson, Dr monica emelko, Dr emil Frind, University of Waterloo, Ontario, canada

FunDing

Natural sciences and engineering research Council of Canada • Canadian Water Network • Ontario Ministry of the Environment • Oxford county, Ontario

ContaCt

Dr David l Rudolph Groundwater (hydrology)

Department of earth & environmental sciences University of Waterloo 200 University ave. W Waterloo, Ontario, N2l 3G1 canada

t +1 519 888 4567 x 36778 e drudolph@uwaterloo.ca

www.water.uwaterloo.ca www.cwn-rce.ca

DaviD RuDolpH is a Professor in the Department of earth and environmental sciences at the University of Waterloo. he specialises in regional hydrogeology and groundwater protection and management. his research includes field investigation and modeling of groundwater flow and contaminant transport with a specific focus on regional groundwater flow systems.

intelligenCe

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