Trent-Severn Waterway Research Articles

Influence of cultural eutrophication, climate, and landscape connectivity on 3 Kawartha lakes (Ontario, Canada) since the early 1800s

Laird KR, Li S, Gushulak CAC, Moir KE, Wang Y, Leavitt PR, Cumming BF. 2023. Influence of cultural eutrophication, climate, and landscape connectivity on 3 Kawartha lakes (Ontario, Canada) since the early 1800s . Lake Reserv Manage. 39:120–140. Paleolimnological analyses of 3 lakes within the Trent-Severn Waterway (TSW) were examined to evaluate the role of regional land-use practices (forestry and agriculture), climate change, and landscape position on cultural eutrophication and lake response over the past ∼200 yr. The lakes were selected to represent lake position along the chain of lakes of the TSW; these 3 lakes vary in lake-water conditions from a lower nutrient headwater lake (Cameron Lake) to more nutrient-rich sites (Pigeon and Stony lakes) downstream. Diatom-inferred total phosphorus (TP) concentrations estimate that all lakes had TP levels of ∼15 µg/L in the 1700s, which increased to ∼20–30 µg/L in the 1800s and 1900s. Significant changes in diatom and Cladocera assemblages circa the 1830s are consistent with increased water levels and elevated phosphorus conditions associated with the intensification of forest harvest, agriculture, and development of the TSW. Diatom-inferred TP levels varied among lakes since the early 1900s, declining in Cameron Lake, increasing in Pigeon Lake, and stabilizing in Stony Lake, reflective of landscape position, degree of water inflow from the northern forested regions, and responsiveness of basins to point-source nutrient reductions and climate change. Timing of changes in TP, and changes in planktonic community composition varied among lakes. Lake production (as pigments) increased coherently in 2 lakes over the past ∼20 yr, and modern algal composition (diatoms and pigments) are lake specific and unique in comparison to the last ∼200 yr, likely reflecting combined effects of climate change and changes in nutrient loading.

Predicting views on private shoreline development in Ontario's historical waterways: Results from an online survey

Private development on shoreline environments has many implications for ecological systems and understanding the social context can help authorities and conservation groups appropriately manage its impacts. This article presents findings from an online non-random sample survey to identify potential factors that may predict individuals’ views on private development on the shorelines of two historic waterways in Ontario: the Rideau Canal (RC) and Trent-Severn Waterway (TSW). Using exploratory multinomial logistic regression analysis, we found that overall perception of environmental threat, perception of shoreline development as a threat, ownership of waterfront property, and type of usage of the waterways are significant predictors of views on private shoreline development in the RC and TSW among respondents to the survey. Authorities and conservation groups can use these results to better anticipate the reactions of individuals and groups to private development projects and tailor engagement programs with property owners and other stakeholders.

Low Benthic Oxygen and High Internal Phosphorus-Loading are Strongly Associated With the Invasive Macrophyte Nitellopsis obtusa (starry stonewort) in a Large, Polymictic Lake

Lake Scugog is an important headwater to the Trent Severn-Waterway in Ontario, Canada. In recent years, notable ecosystem-level changes have occurred coinciding with the emergence of the non-native invasive charophyte Nitellopsis obtusa. Despite N. obtusa arriving in North America in the early 1970s, studies documenting the impact of N. obtusa on invaded ecosystems are scarce. Given the increasing dominance of N. obtusa in inland waters of the Great Lakes basin, we investigated the ecosystem-level impacts of N. obtusa in Lake Scugog over a 3-year period. We show for the first time a strong association between N. obtusa occurrence and biomass with benthic anoxia in this shallow, polymictic lake. Benthic dissolved oxygen concentrations were significantly lower (p-value < 0.001) at sites with N. obtusa compared to sites without N. obtusa. Additionally, N. obtusa biomass was a negative predictor of near-bed oxygen concentration (R2 = 0.59, p-value < 0.001). Knowing that anoxia can promote the internal loading of phosphorus, we measured soluble reactive phosphorus (SRP) in the pore-water of sediments at each site, and found N. obtusa biomass explained 90% of sediment pore-water SRP (R2 = 0.90, p-value < 0.001). These notable associations between N. obtusa and key lake elements indicates that N. obtusa may be acting as an ecosystem engineer in invaded lakes by altering the biogeochemical fate of oxygen and phosphorus.

Population density contributes to the higher functional response of an invasive fish

Invasive species often have higher functional responses than native analogs. A better understanding of the functional response of invasive species could help explain the effect of these species on native prey communities, and aid in the development of tools for predicting invasion impact. We investigated the role of population density and location along the invasion pathway in determining the functional response of an invasive fish. We used invasive round goby (Neogobius melanostomus) collected from the Trent-Severn Waterway in Ontario, Canada to test for differences in the functional response of fish from high and low density sites, and from different locations along the invasion pathway. We also compared the functional response of round goby with that of northern logperch (Percina caprodes), a native species occupying the same niche. The density of the invasive predator population influenced its functional response, with attack rate being significantly higher for fish from high-density sites compared to fish from low-density sites. Functional response of individuals living at the invasion front was not significantly different from those living in established areas. The higher functional response of round goby compared to its native analog was associated with shorter handling time. Patterns in functional response curves were not explained by differences in diet among wild populations. Our research demonstrates that population density influences the functional response of an invasive species, and therefore should be accounted for when evaluating the functional response of a potential invader.

An Object-Based Image Analysis Workflow for Monitoring Shallow-Water Aquatic Vegetation in Multispectral Drone Imagery

High-resolution drone aerial surveys combined with object-based image analysis are transforming our capacity to monitor and manage aquatic vegetation in an era of invasive species. To better exploit the potential of these technologies, there is a need to develop more efficient and accessible analysis workflows and focus more efforts on the distinct challenge of mapping submerged vegetation. We present a straightforward workflow developed to monitor emergent and submerged invasive water soldier (Stratiotes aloides) in shallow waters of the Trent-Severn Waterway in Ontario, Canada. The main elements of the workflow are: (1) collection of radiometrically calibrated multispectral imagery including a near-infrared band; (2) multistage segmentation of the imagery involving an initial separation of above-water from submerged features; and (3) automated classification of features with a supervised machine-learning classifier. The approach yielded excellent classification accuracy for emergent features (overall accuracy = 92%; kappa = 88%; water soldier producer’s accuracy = 92%; user’s accuracy = 91%) and good accuracy for submerged features (overall accuracy = 84%; kappa = 75%; water soldier producer’s accuracy = 71%; user’s accuracy = 84%). The workflow employs off-the-shelf graphical software tools requiring no programming or coding, and could therefore be used by anyone with basic GIS and image analysis skills for a potentially wide variety of aquatic vegetation monitoring operations.

Object-based analysis of UAS imagery to map emergent and submerged invasive aquatic vegetation: a case study

Small unmanned aircraft systems (UAS) combined with automated image analysis may provide an efficient alternative or complement to labour-intensive boat-based monitoring of invasive aquatic vegetation. A small mapping drone was assessed for collecting high-resolution (≤5 cm/pixel) true-colour and near-infrared imagery revealing the distribution of invasive water soldier (Stratiotes aloides) in the Trent–Severn Waterway, Ontario (Canada). We further evaluated the capacity of an object-based image analysis approach based on the Random Forests classification algorithm to map features in the imagery, chiefly emergent and submerged water soldier colonies. The imagery contained flaws and inconsistencies resulting from data collection in suboptimal weather conditions that likely negatively impacted classification performance. Nevertheless, our best-performing classification had a producer’s and user’s accuracy for water soldier of 81% and 74%, respectively, an overall accuracy of 78%, and a kappa value of 61%, indicating “substantial” accuracy. This trial provides an instructive case study on results achieved in a “real-world” application of a UAS for environmental monitoring, notably characterized by time constraints for data collection and analysis. Beyond avoiding data collection in unfavourable weather conditions, adaptations of the image segmentation process and use of a true discrete-band multispectral camera may help to improve classification accuracy, particularly of submerged vegetation.

Assessing stakeholder impacts and adaptation to low water-levels: the Trent-Severn waterway

The Trent-Severn Waterway in central Ontario, Canada, is a large inland water system. It is managed for a broad range of stakeholders with different needs and expectations, creating a complex management context. Although variations in water levels occur, extreme low water-level events may increase in the future due to climate change, challenging management practices, in addition to requiring adaptation to reduce impacts. A modified policy Delphi was used to generate and evaluate ideas related to historical and future water-level impacts and adaptations. The paper presents the perspectives of three groups—cottagers and homeowners (CH), government (G), and industry and business (IB)—on their experiences with historic low water-levels, as well as their perspectives on future impacts and adaptations using two water-level scenarios: a moderate decrease of 25 cm and a more severe 50 cm decline. Shared impacts and adaptations (individual and collective) were identified along with those that were unique to a group. The likelihood of and consensus on potential impacts and most adaptations increased with the severity of water-level reduction. All groups indicated a higher likelihood of using collective rather than individual adaptations with the severe scenario, and in some cases, their contacts for assistance with adaptation broadened. While the modified policy Delphi requires significant effort by the analyst and respondents, it provides a useful framework for generating and analyzing perceptions and preferences of diverse stakeholders.

To boldly go where no goby has gone before: boldness, dispersal tendency, and metabolism at the invasion front

The successful establishment and expansion of invasive species may be linked to the behavior and dispersal tendency of individuals within an introduced population. To test the prediction that the boldest individuals, with the greatest dispersal tendency would be concentrated in the area of active range expansion, we compared the behavior, dispersal tendency, and metabolic rate of male round goby ( Neogobius melanostomus ) sampled from the expanding edge of their range with those sampled from an established area in the Trent–Severn Waterway, Ontario, Canada. Behavior and dispersal tendency were assessed in an artificial flume at 2 different water velocities using individuals caught in the spring and autumn of 2013, while resting metabolic rate (RMR) was determined using intermittent flow-through respirometry on fish collected in the autumn only. Round goby from the edge of their expanding range emerged from a shelter sooner, moved farther and faster in the flume, and had higher RMRs than individuals from established areas within the river. Neither water velocity nor season of capture was important in explaining the variation in time of emergence or movement. The higher proportion of bold individuals with high dispersal potential at invasion fronts facilitates further dispersal of round goby populations, and could help explain the rapid expansion of this species in North America and Western Europe. However, the benefits of bold phenotypes in terms of dispersal may be offset by increased energetic costs while at rest.

Injury Rates of Freshwater Turtles on a Recreational Waterway in Ontario, Canada

Highly aquatic freshwater turtle species are at risk of vehicular encounters during terrestrial nesting forays; however, injuries and mortality incurred during boat collisions may present considerable threats as well. Additionally, effects of other injuries from predation or disease may augment the likelihood of population decline. We report injury rates from captures of two turtle species-at-risk, Northern Map Turtles (Graptemys geographica) and Stinkpots (Sternotherus odoratus), along the Trent–Severn Waterway in Ontario, Canada. We examined whether habitat fragmentation attributable to locks and dams would result in higher rates of boat propeller and predation injuries because of the higher human impact in fragmented areas. Fragmented areas of the waterway had similar injury rates to continuous areas; however, more female Map Turtles (28.6% of captured females) had injuries consistent with boat propeller strikes than males (12.8%). Map Turtles in general had higher rates of injury (48.5%) than Stinkpot Turtles (20.0%), although actual rates of boat or predator encounters may be confounded by the lowered probability of survival for a smaller-bodied turtle (e.g., Stinkpot, male Map Turtles). All species encountered on the waterway, including incidental captures of Blanding's Turtles (Emydoidea blandingii) and Snapping Turtles (Chelydra serpentina), showed some evidence of boat propeller strikes, suggesting that conservation strategies for aquatic turtle assemblages should consider restricting boat access, speed limits, or both, in areas of high turtle densities.

Modeling round goby Neogobius melanostomus range expansion in a Canadian river system

Abstract We applied a gamma transit time model to predict the rate of range expansion of the round goby ( Neogobius melanostomus Pallas, 1814) in the Trent-Severn Waterway (Ontario, Canada). Gamma distributions were fit to actual transit times of the population front from 2009 to 2011. A lack of model fit in the second year is thought to be indicative of an upstream bait bucket introduction, and this model may be useful for identifying such events. Range expansion predictions were highest in high quality habitats at 9.3 km/year, with a 5% probability that highly mobile individuals may disperse 27 km/year. The model also predicts the arrival time of the population at any distance from the population front with a given confidence interval. The estimation of a timeline for range expansion and determining underlying factors affecting the spread of invasive species could inform preventative strategies. This model is potentially useful in predicting transit times of other invasive species expanding their range in linear space, and in separating natural population expansion from additional human-assisted movement in the same system.

Range expansion dynamics of the invasive round goby (Neogobius melanostomus) in a river system

The rates of upstream and downstream range expansion of the round goby (Neogobius melanostomus) were examined in the Trent-Severn Waterway in 2009 and 2010. Relative abundance, demographics, and habitat use were also compared between areas of range expansion and a longer established area to determine how these characteristics varied along the invasion pathway. Round gobies were sampled using an angling removal method in May and August of 2009 and 2010 at 75 sites at each area of range expansion and 25 sites near the center of their range where they first became established in the waterway. Areas of range expansion had initially low abundance and low site occupancy in May 2009 relative to the longer established area. Large increases in abundance and site occupancy were observed over the first summer of occupation, but with limited range expansion. Rapid range expansion was observed during the non-reproductive season at the upstream edge of range. Individuals sampled in the expanded upstream range were small and female biased relative to other range locations. Round gobies also exhibited higher habitat selectivity for rocky substrates at range edges than in the longer established area. These characteristics of seasonal dispersal, biased demographics of dispersers, and high habitat selectivity may be important components of successful range expansion of the round goby in invaded ecosystems.

Spatial Ecology and Population Genetics of Northern Map Turtles (Graptemys geographica) in Fragmented and Continuous Habitats in Canada

Abstract In riverine systems, the construction of locks and dams may present barriers to movement for aquatic organisms and effectively fragment otherwise continuous populations. We examined the spatial ecology and population genetics of northern map turtles (Graptemys geographica) in the Trent-Severn Waterway (TSW), Ontario, Canada. We hypothesized that the locks and dams on the TSW are fragmenting map turtle habitats and creating barriers to movement, and predicted that turtles from fragmented habitats have significantly reduced home range sizes and daily movements compared to turtles from unfragmented habitats, and that populations on either side of a lock and dam would be genetically distinct. Home ranges and average daily movements were smaller for turtles from fragmented habitats compared with continuous habitats, indicating that locks and dams are restricting mobility. However, populations in fragmented habitats showed none of the predicted genetic consequences of fragmentation (e.g., reduced heter...

Demographic differences among populations of Northern Map Turtles (Graptemys geographica) in intact and fragmented sites

Habitat fragmentation is a leading cause of reptile declines worldwide. We examined demographic differences between populations of Northern Map Turtles, Graptemys geographica (Le Sueur, 1817), inhabiting intact and fragmented sites along the Trent–Severn Waterway (TSW) in Ontario over two field seasons. We examined population densities, sex ratios, body size, and growth rates in two control sites and two fragmented sites (where the waterway is disrupted by dams). We predicted that population density would be higher in control sites, and that sex ratios would differ among sites. Abundance was greater than expected, but densities could not be compared owing to a lack of recaptures. Sex ratios in control sites were slightly male-biased and were significantly female-biased in fragmented sites. Turtles in fragmented habitats were significantly smaller than those in control habitats. Estimated growth rates of juveniles and males were significantly reduced in fragmented populations compared with controls. We hypothesize that habitat alterations in fragmented sites are differentially affecting demographic classes because of the intersexual niche divergence observed in Map Turtles. We emphasize the need for further research to examine the interactions between habitat alteration and invasive species and the effects they are having on Northern Map Turtle populations.

Effectiveness of Piscicides for Controlling Round Gobies ( Neogobius melanostomus)

Round gobies (Neogobius melanostomus) were introduced to the Great Lakes presumably as a result of ballast water releases from seagoing freighters returning from European water bodies. These unwelcome fish have become established in the Great Lakes region and are expanding their range to suitable portions of other interior drainage basins including the Mississippi River traversing the central United States and the Trent-Severn waterway spanning south-central Ontario. If the invasion continues, use of chemical toxicants as a control measure may be necessary. Toxicity tests of the currently registered piscicides antimycin, rotenone, 3-trifluoromethyl-4-nitrophenol (TFM), and Bayluscide ® were conducted with three fish species native to the Great Lakes and round gobies collected from the Illinois Waterway. Tests indicated that round gobies are sensitive to all of the piscicides, however, the level of sensitivity is similar to that of the native fish species tested. Therefore, currently registered piscicides have limited potential to selectively remove round gobies. Bottom-release formulations of Bayluscide ® and antimycin were also evaluated as control agents for the normally bottom-dwelling round goby. Avoidance behavior tests demonstrated that the round goby did not react to the presence of either chemical. Therefore, the bottom-release formulations may have some application for the selective removal of round gobies, and may be one of the few tools presently available to fishery managers to help limit the range expansion of this invasive fish.

The Biology of Invasive Alien Plants in Canada. 7. Cabomba caroliniana A. Gray

The freshwater aquatic plant Cabomba caroliniana, or fanwort, was recently reported in a lake northeast of Peterborough, Ontario, where it has successfully established and survived winter conditions since at least 1991. This is the first documented occurrence of fanwort becoming naturalized in Canada. Fanwort is a popular aquarium plant that is native to South America and possibly the southeastern United States and has been introduced in several Asian, Pacific and European countries through the discarding or deliberate planting of aquarium plants in natural waterways. It is particularly invasive in China, Japan and Australia, and in parts of the United States, where its range is spreading. Fanwort grows rapidly and forms dense stands that clog waterways, impeding flow, obstructing navigation, altering fish habitat and excluding other vegetation. It does not produce mature seed in the northern parts of its North American range, but can multiply clonally and spread quickly by stem fragmentation. It produces turion-like stems at the end of the growing season, which assist in over-wintering under adverse conditions. Fanwort is difficult to control with herbicides and is resistant to mechanical management techniques as populations can quickly re-establish from plant fragments. Populations near the Trent-Severn Waterway in Canada are extensively established and management tools are not available to attempt eradication. An integrated management plan that focuses on early detection and rapid response in surrounding water bodies may succeed in mitigating the economic and environmental impacts and limiting the spread of fanwort. Key words: Cabomba caroliniana, fanwort, cabomba de Caroline, CABCA, aquatic plant, weed biology, invasive alien

The influence of residential and cottage development on littoral zone fish communities in a mesotrophic north temperate lake

We used the rapid visual technique (RVT), an underwater visual assessment method developed in marine environments, to assess the influence of residential and cottage development on littoral zone fish communities in Pigeon Lake, a shallow, mesotrophic Canadian lake with extensive shoreline disturbance. We used RVT to assess 135 sites, stratified by degree of residential and cottage development (undeveloped, moderately developed, highly developed) and habitat type (three substrate/vegetation categories). Sites with different degrees of residential and cottage development did not differ significantly in species richness. When the RVT site scores of each species life stage (young-of-year, juveniles and adults) were compared among development categories, only 11% of species life stages showed significant differences; all were most abundant in moderately developed sites. Habitat had a greater influence than development on within-taxon abundance, as 46% of species life stages showed significant among-habitat differences in RVT score. The absence of significant fish community differences between developed and undeveloped sites may be due to the shallowness, extensive macrophyte cover and raised shorelines from the construction of the Trent-Severn Waterway. However, there do appear to be changes in the fish community over the last 35 years, as six cyprinids and one cyprinodont species that were present in Pigeon Lake in the 1970s were not detected by our sampling. RVT provided comparable data to that obtained by straight line transects on the relative abundance of species in the lake, but RVT was more effective at detecting species and life stages present at individual sites.

James T. Angus, A Respectable Ditch. A History of the Trent-Severn Waterway 1833-1920, (Kingston and Montreal: McGill-Queen’s, 1988). Robert W. Passfield, Technology in Transition: The 'Soo' Ship Canal 1889-1985, (Ottawa: Environment Canadian Parks Service, 1989).

James T. Angus, A Respectable Ditch. A History of the Trent-Severn Waterway 1833-1920, (Kingston and Montreal: McGill-Queen’s, 1988). / Robert W. Passfield, Technology in Transition: The 'Soo' Ship Canal 1889-1985, (Ottawa: Environment Canadian Parks Service, 1989).. Un article de la revue Scientia Canadensis (Volume 16, numéro 2 (43), 1992, p. 123-222) diffusée par la plateforme Érudit.

La machine locomotive en France des origines au milieu du XIXe siècle by Jacques Payen

534 Book Reviews TECHNOLOGY AND CULTURE and, in cities and towns, the movement of goods depended on human and animal energy right up until 1914, when mechanization in the form of motor vans and lorries began to have an effect. From the standpoint of scholarly research, Transport in Victorian Britain constitutes a major contribution to the history of transporta­ tion in Britain. The authors’ conclusions are soundly based on a thorough analysis of recent research on many related subjects; they also point out aspects of transportation history not covered in the book for further examination. The inclusion of many tables, graphs, maps, figures, general statistics, and a complete bibliography, together with the authoritative summaries, will render the book a valuable resource for students of economics, geography, and transport history. But the crisp and highly readable writing style of the authors will extend the book’s appeal beyond these academic specialists to others with more pedestrian interests in the history of British transportation. James T. Angus Dr. Angus is a professor of educational administration in the School of Education, Lakehead University. He is the author ofA Respectable Ditch: A History ofthe Trent-Severn Waterway 1833-1920 (Montreal, 1988). La machine locomotive en France des origines au milieu du XIX' siècle. By Jacques Pâyen. Lyon and Paris: Presses Universitaires de Lyon and Éditions du CNRS, 1988. Pp. 262; illustrations, notes, appendixes, bibliography, index. F 160.00 (paper). In describing the earliest locomotives used in France, this book recounts the transfer of technology from the United Kingdom but is not detailed enough to show the individual contribution of the French mind. It reveals that in 1846 France had as many British-built as French-built engines in service, but four years later there were five times more French than British. The book begins with five useful chronologies, each dealing with the creation of what later became one of the great railways that existed before the SNCF. Traffic growth is implied in tables of locomotive stock additions, year by year. This is followed by a fair and well-documented account of the origins of the multi-firetube boiler, developed independently by Robert Stephenson and Marc Seguin, demonstrating that Seguin’s locomotive, shorn of its blowing fans and provided with a blast pipe, returned a similar boiler efficiency to that obtained with the Rocket. The main part of the book divides the French locomotives of the period into four generations, which at least has the advantage of conveniently organizing the text and very full references (the book’s great virtue), as well as the plentiful illustrations. This part occupies TECHNOLOGY AND CULTURE Book Reviews 535 the equivalent of some sixty pages of text and notes, plus 111 illustrations: not a great length, but the information is not available in any other single book and is here presented concisely. This is a book for the technically informed historian to use and for the historically minded engineer to enjoy. It is full of things one had not thought about, such as that the Strasbourg-Bâle line was the first international main-line railway, or that the French revolution of 1830 explains why the Planet type did not reach France in any quantity; but it scarcely touches on the finer details of progress in design that rapidly turned the locomotive into a reliable machine. Jacques Payen draws heavily on Warren’s A Century of Locomotive Building by Robert Stephenson and Co., but Ahrons’s The British Steam Locomotive, 1825— 1925, a superior source dealing with other makers, is nowhere referred to. Neither, surprisingly, does the bibliography mention Jahn’s Die Dampflokomotive in entwicklungsgeschichtlicher Darstellung ihres Gesamtaufbaues, published in 1924. These two are probably the most meticulously researched locomotive histories that have appeared, but one has to read them to realize this. Alongside Ahrons, Jahn, and Warren, this is a slighter work—a monograph, not a treatise. Written by a distinguished historical researcher with help from a technical journalist and a theoretical physicist, it shows signs of remoteness from engineering reality. No engineer would describe the “Buddicom” type as an evolved “Patentee”: it was an alternative, designed to avoid the faults of the “Patentee” by eliminating...

MULTIPLE USE MANAGEMENT OF THE RIDEAU AND TRENT-SEVERN WATERWAY RESERVOIR SYSTEM

First a military system and a commercial transportation route, recreational boating is today the major use of the extensive Rideau and Trent-Severn Waterway systems. Since 1972, these canals have been managed by Parks Canada in the context of the Canada - Ontario - Rideau - Trent-Severn Agreement (C.O.R.T.S.). In fact, Parks Canada’s responsibilities extend throughout adjacent reservoir lakes totalling over 150,000 hectares and integrate programs involving: the maintenance of navigation channels; water level control; development of support facilities for boater recreation but also for land based users; the physical maintenance of the control structures and locks; natural, cultural and historical resources conservation and interpretation; and enhancement of general recreational environment.A variety of other federal, provincial and municipal agencies play a role in the management of these waterways. Water uses also include hydro-electric power generation, irrigation for agriculture, water supply for domestic or industrial purposes, and resource harvesting. Together, supported by research and monitoring, these multiple uses constitutes a practical example of managing a reservoir ecosystem.

TRENT-SEVERN WATERWAY CONFLICTS

Whenever a large number of different activities are based upon a single resource, conflicts are inevitable. The Trent-Severn system of dams controlling the water levels and flows in a large recreational area is just such a situation. Whitewater canoeing requires flow to be taken from reservoir headwater lakes while cottaging on these lakes is enhanced when the water level remains high. Lock operation with adequate advertised draught through the navigation route, as planned and designed for, requires that evaporation losses from canal route lakes be replaced with water from the reservoir lakes, also detrimental to the reservoir cottager. Fish spawning requires certain flows of water at certain times in certain locations just at a time in some years when flow must be reduced to ensure filling the lakes for summer. Power production, flood control, agriculture, water quality and municipal water supply are among the further concerns of Trent-Severn Waterway in controlling flows.The primary raison d’etre of the...