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AC Atienza, Brendan Bate, Shannon Smithwick, Steff Stephansson, Kaleigh Watson, Andrew Wilson.
Dams and other water infrastructure (see here for more discussion) are a broad class of projects that play vital roles in modern society, providing benefits ranging from hydroelectric power, flood control, water supply security and on to recreational services. These projects can be the classic “grey” infrastructure of dams but also the “green” infrastructure of nature-based solutions such as created wetlands. Some examples of such projects are listed below:
The community and ecosystem pros and cons of such projects depend on the type of project, how it is implemented and the nature of the problem it is intended to address. There is no “one-size-fits-all” solution and there may be several ways to achieve a desired outcome. And, different stakeholder groups are likely to have strong and very different opinions on the merits or otherwise of a given project.
The following article is a high-level overview of some of the issues of such infrastructure-focussed water management approaches. We will also explore some of the challenges and opportunities in balancing development and conservation. This article will not address water distribution, water treatment or wastewater management.
Dams serve multiple roles, each critical to the development and maintenance of human societies. They provide essential services including holding water for domestic, agriculture and industrial use, generating hydroelectric power, and recreation. While dams serve multiple functions, their operation and design is optimised to prioritise a very small number of services as some services may conflict with others. For example, a flood-control dam needs the reservoir to be kept relatively empty to preserve space to capture flood run off. On the other hand, a hydro-power dam works best when the reservoir is kept full to give the greatest possible pressure on the turbines and to cater for years of lower flows. It is not possible to optimally operate the same dam for both purposes simultaneously.
For example:
All these dams are (or, where still under construction, will be) central to regional development and growth and highlight the importance of water infrastructure in supporting modern societies.
As noted above, dams are only one type of water management infrastructure. Others include flood barriers such as berms (also called dykes/dikes/levees), diversion channels or channelised rivers. Such structures are designed to manage floods up to a certain size. If the flood exceeds that design size, the protection they offer is severely compromised.
On a small scale, “dugouts” are used on farms to store run-off for later use. They can also offer an environment favourable to plants and wildlife but need careful planning and management [6]. Similarly, the work of organisations such as Ducks Unlimited to restore wetlands can help to restore natural water bodies and improve water quality.
The construction of dams can have profound positive and negative socioeconomic effects on local communities. In a nutshell: it’s complicated!
Dams may bring benefits such as flood control, groundwater recharge, recreation opportunities, electricity, and a more secure water supply for communities, agriculture, and industry. Developed water resource infrastructure tends to encourage economic growth and community prosperity by providing a reliable water supply [7]. However, the picture is complicated with research suggesting the size of the dam is linked to whether or not areas near to the dam benefit or not – larger dams tend to primarily economically benefit more distant populations [8].
Dams alter natural river ecosystems in significant ways, with far-reaching consequences for biodiversity and ecosystem services. The fragmentation, or breaking up, of rivers by dams disrupts the natural flow regime, impedes sediment transport, and alters habitats [21]. These changes can degrade aquatic and riparian ecosystems, leading to the loss of species diversity, changes in species composition, and habitat degradation [22]. Additionally, dams can impede fish migration, disrupt nutrient cycling, and exacerbate water quality issues such as eutrophication and sedimentation. These environmental impacts have implications for ecosystem resilience, food security, and the provision of ecosystem services.
Altering the natural flow of water bodies can impact water quality by changing how sediment such as sand is moved by the flow of water and reducing the flow of nutrients. Stagnant or still water behind dykes can lead to lower oxygen levels, affecting fish and other aquatic life. Additionally, the disruption of natural flooding cycles, which replenish nutrients in floodplains, can impact the health of these ecosystems [23].
An effect of dams which is not always appreciated is the potential for the reservoirs to emit carbon-dioxide and methane from the breakdown of plant matter. New research [24] suggests that, on a global scale, reservoirs are a significant source of these gases although the extent varies according to their proximity to the equator. Reservoirs in the tropics and subtropics produce more of the gasses than reservoirs in the higher latitudes. This is a particular concern as it is estimated that 65-75% of new hydropower reservoirs will be built in the topics and sub-tropics in coming decades.
However, the bigger issue comes from people’s perception of being “safe”. When we develop infrastructure to protect communities against flooding, a consequence becomes the building of new neighbourhoods and other developments in areas previously known as flood prone that are now seen as “safe” from floods. This means that while the probability of flooding may be reduced, the value of the houses and buildings as well as the number of people vulnerable to flooding increases if there was to be a failure of the water management infrastructure. This increases the risk of damage occurred and increases the costs of actions like rehousing people affected in comparison to if the infrastructure hadn’t been built (e.g. British Columbia’s Sumas Prairie [27]). The core mistake is in thinking in absolute terms: that infrastructure makes one “safe”. The truth is that infrastructure should make one “safer” but there is always a remaining level of risk. This is most easily seen with dykes: they are built and designed to manage storms up to a certain size. The protection they offer against a bigger-than-designed-for storm is greatly reduced as the water simply flows over the top of the dykes and, should the dykes fail, the failure may make the damage worse than if the dykes hadn’t been there in the first place.
Another source of “new” risk is the effects of a changing climate on storm frequency and intensity. A structure is designed to a “service level” of protection against extreme water events of a certain size. For example, a new structure might be designed to protect an area against, say, a storm with a 1:200 chance of happening. This means that a bigger storm, say 1:300, will not be protected against but the builders of the structure are prepared to accept the consequences of a storm that rare.
However, climate change is increasing both the intensity and the frequency of severe storms. Which means, in effect, that a storm in Canada which currently occurs with a 1:50 frequency is expected to become a 1:10 event by the late 2000’s [28] under the RCP8.5 emissions scenario.
The result of this is that, over time, the “service level” protection provided by the new structures declines. And that communities who had thought they were protected against a, say, 1:50 event will only have a fraction of that protection.
A (very brief) description of RCP scenarios: RCPs or Representative Concentration Pathways are climate change scenarios which have been adopted globally to project future greenhouse gas concentrations. These “pathways” describe future greenhouse gas (GHG) (e.g. Carbon-dioxide) concentrations and are used to make predictions of our future climate at various dates in the future. RCP 8.5 is the most extreme (i.e. most GHG) scenario and assumes that the world’s GHG emissions will continue to increase in the 2000’s. See here for more information.
Dams and dykes are vitally important tools in community protection against flooding and dam reservoirs provide valuable water management capabilities. However, communities protected by such structures need to be cautious and deliberate about permitting further development in the protected areas.
Water management infrastructure can and does bring both benefits and costs to communities and ecosystems. Trying to balance those benefits and costs is not simple [29]. Communities need to involve all stakeholders in the necessary discussions to choose the most appropriate and long-term sustainable solution. Ensuring the resilience and health of both human and natural communities requires ongoing effort and collaboration by all stakeholders.
Have a look around your community and see how much water management infrastructure you can find.
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Ross has extensive executive experience in Operations, Governance, Information Technology and Strategy at the board and senior management level including Mancal Corporation, Mancal Energy, Highridge Exploration and Atlantis Resources. He has worked in Oil and Gas, Coal, Commercial Real Estate, Portfolio Management, Recreation, Retail and Water and Wastewater Treatment. His experience is also geographically diverse having overseen operations in Canada, the United States, United Kingdom and Northern Ireland. Additionally, he has been on the board of companies with operations in Argentina, Azerbaijan, Barbados, Kazakhstan, and Russia. He has served on numerous Public, Private and Not for Profit Boards across a number of industries.
Ross has been active on several industry Boards and committees including the Canadian Association of Petroleum Producers (CAPP) and The Schulich School of Engineering Industry Advisory Council at the Schulich School of Engineering.
Brian is a seasoned Cleantech entrepreneur with a proven history of successfully bringing complex water technologies to the market. With over 25 years of experience, he has led various organizations to achieve significant milestones in the industry.
Having started as the founding CEO of the Pressure Pipe Inspection Company (PPIC) and later taking the helm at the Water Technology Acceleration Project (WaterTAP), Brian’s entrepreneurial spirit has been instrumental in driving innovation and growth within the sector.
He is an active investor in the cleantech sector and has served on many boards including the Ontario Clean Water Agency.
Actively engaged in industry associations like AWWA, WEF, IWA, and ASCE, Brian enjoys collaborating with fellow professionals to promote advancements in the field.
Brian holds an undergraduate degree and a PhD in Physics from Queen’s University, which has provided him with a solid technical foundation. As a member of the Institute of Corporate Directors, he brings valuable insights to corporate governance.