18 March 2011

Canada Water Week: Climate Change in British Columbia

This post was chosen as an Editor's Selection for ResearchBlogging.orgIn support of Canada Water Week (14 - 22 March) I pledged to Water Canada that I would post an article on the status of hydro-electric projects in the western province of British Columbia (BC), including the potential impacts of climate change on the operation of current facilities and the feasibility of planned projects.  I may range a bit beyond that planned topic, however, with some more recent reading on several issues.  Instead of talking just about the energy productivity of the province's waterways, there is a growing discussion on the overall health of the Pacific Northwest of North America, including several states in the Northwest US, the western provinces of Canada, and the state of Alaska.  Though many topics cross such political boundaries, as natural resources so often do, I'll do my best to stick to the scientific (not political) perspective on these.  And for that matter, not being a Canadian myself, I welcome your comments to correct and/or support the information provided here.

credit David Nunuk/Pew Environment Group
I chose to focus on BC because...I like it!  No, I have not been there yet, but it appeals to me greatly: rugged mountains in the Rockies and Coast Ranges, unreal blue-green high mountain lakes, glaciers dropping into the Pacific, vast forested areas, wild salmon runs in amazingly fresh rivers, native populations of both people and animals in their sacred spaces, hiking and mountain biking trails by the hundreds of miles... And yet, these are almost all idealizations in some way or another, and sadly so: instead, there are old-growth and even second-growth forest areas now clear-cut by the hectare, fire scars across the landscape, mining and drilling in those massive stone cathedrals, streams and rivers polluted by chemical waste and sediment runoff, exploitation of oil sands in the northeastern province contiguous with extractive projects in northern Alberta, thousands of miles of all-weather logging and supply roads across an increasingly fragmented landscape, and the decimation of animal populations as native communities and their livelihoods are weathered away by relegation to subservient rights, land takings, and the invasion of "modern" civilization and its vices.  This is the land of the Golden Spruce, an ancient and sacred tree cut down by an activist logger, apparently in protest against the industrial ravages of the Canadian provinces.  This is the land of the Peace River, which is under threat from territorial disputes involving First Nations claims and BC Hydro's existing and planned hydropower projects.  This is a land through which flows the Upper Columbia, one of the most fragmented river basins in the world, passing out of the US on its tortuous course through the Rocky Mountains and eventually back into the US on its way to the Pacific Ocean.  This is the land of Whistler and the Inside Passage, Kamloops and Vancouver Island...snowboarding in the winter, mountain biking in the warm seasons, hiking all year, science and nature and our interactions with those all around!  It's the stuff dreams are made of, at least for this outdoorsy American boy. 

BC Hydro service area, almost all of the province
Unfortunately, decades of lax environmental stewardship and unenforced regulatory compliance at the federal and provincial levels have left a patchwork of legislation and litigation with massive holes exploited repeatedly by the extractive industries, especially for timber and minerals.  While these products are exported for finishing and use, the degraded landscape is left behind, and there are few better signals of environmental health than the provincial waters.  In this regard, BC holds abundant water quantities of increasingly threatened quality, and the manner with which riparian areas are treated will make a huge difference in the sustainability of these resources.  We have seen previously, and will explore again, how water and energy are connected.  It's not quite as complicated in BC as in the Colorado River basin, but it's still relevant here.

With abundant supplies of water but a need for electricity in growing populations centers, in addition to a few initial coal- and gas-burning power plants, Canadians in the western province of BC turned to an ostensibly "clean" source of energy.  The principal electric utility is BC Hydro, officially known as the BC Hydro and Power Authority (BCHPA), created in 1961 and regulated by the British Columbia Utilities Commission as a power (not water) provider.  BC Hydro operates 30 hydropower facilities (and shares operation of one more) for 86% of its energy portfolio, supplying electricity to ~1.8 million Canadians over 95% of the province.  The following table lists the numerous hydropower operators in BC with some of their infrastructure information, derived from a detailed list of hydropower stations throughout BC.

Company Hydropower
facilities*
Dates
constructed
Capacity range
(MW)
Total capacity
(MW)
BC Hydro 30.5 1912 - 1984 2.6 - 2730 10,345.6
Brookfield Renewable Power 4.5 1911 - 2003 1.5 - 46 113.1
Capital Power Corporation 2 1996 - 2003 7 - 33 40
Capital Power Income 2 1990 - 1996 5.7 - 52 59.7
Cloudworks Energy 6 2010 16.7 - 33.5 151.8
Columbia Power Corporation 3 1944 - 2009 120 - 185 450
Fort Chicago Energy Partners 3 2004 - 2009 11 33
FortisBC 5 1907 - 1993 18 - 66 253
Innergex Renewable Energy 3 2004 - 2010 7.5 - 50 107.5
Macquarie Power & Infrastructure 2 1997 - 1999 3 - 17 20
Plutonic Power 2 2010 73 - 123 196
Renewable Power Corp. 2 2004 - 2009 9.3 - 9.8 19.5
Summit Power 2 1994 - 1996 5.6 - 14 19.6
Synex Energy Resources Ltd 2 2004 - 2009 2.8 - 3.8 6.6
TransAlta 2.5 1995 - 2005 10 - 45 47.5
Single-facility companies (22) 21.5 1905 - 2009 0.1 - 790 1140.6
Total/Composite: 37 companies 93 1905 - 2010 0.1 - 2730 13,003.5
*values of 0.5 indicate cooperative facilities: the facility at Waneta Dam is shared by BC Hydro and Teck;
the facility at Pingston Creek near Revelstoke is shared by Brookfield Renewable Power and TransAlta.

Buried in that table are some interesting figures.  First, BC Hydro's hydropower constitutes just under 80% of all the hydropower production in BC with just about one-third of all the facilities in operation.  BC Hydro operates more hydropower facilities than all of the single-facility companies combined, with a total generation capacity more than ten times that of the independent single-facility operators.  The single largest hydropower facility in BC is the 2,730 MW Gordon M. Shrum Generating Station at W.A.C. Bennett Dam, built in 1968 on the Peace River and operated by BC Hydro.  BC Hydro operates four of the top five and 7.5 of the top ten hydropower facilities (in terms of generating capacity) in the province; one of those facilities is the 490 MW Waneta Dam that is shared by BC Hydro and Teck (hence the 0.5 in my accounting here).  The fifth-largest facility in BC is the Kemano Power Station on the Nechako River at Kenney Dam, the largest earthfill dam in the world when it was built in 1953.  Kemano is now operated by Rio Tinto Alcan, an international mining conglomerate recently expanded from its global base in South America.

W.A.C. Bennett Dam and Williston Lake on the Peace River,
operated by BC Hydro
What is not clear from this table, or the one on Wikipedia (though deeper research would reveal the answers), is the difference between large dams with massive reservoirs powering the hydroelectric generating station and smaller projects that operate on a run-of-the-river basis, where little impoundment is developed but power generation is more seasonally varied according to the river flows.  There are obvious advantages to the almost-instant power capacity of the large dam and reservoir configuration, which is especially useful for scheduling of generation for periods of peak demand.  The drawbacks, however, are massive and almost endless: massive flooding for reservoir creation, displaced peoples, and the emerging impacts of greenhouse gas emissions from biodegradation in hypoxic sediments at the reservoir bottom and edges.  Displacement of indigenous peoples is a particularly prevalent issue among BC hydropower and other industries in their negotiations with the First Nations over land, mineral and timber rights as well as rights-of-way for all-weather roads, power transmission lines and seismic testing instrumentation, each of which results in forest clear-cutting and fragmented habitat for animals and the humans who depend on the forest resources.  Climate change is, at this point, the added pressure of foresight on an already-stressed ecological dynamic between humans and nature.

Hugh Keenleyside Dam, a run-of-the-river hydropower station operated by
BC Hydro, and the newer Arrow Lakes Generating Station, owned by the
Columbia Power Corporation, on the Columbia River (Wikimedia Commons)
Not even considering the general trend of anthropogenic climate change, there are already studies indicating that well known multi-year climate cycles, such as ENSO and the Pacific decadal oscillation (PDO) [1], provide strongly correlated indications of temperature and precipitation cycles in the Pacific Northwest of the US, including the Columbia River Basin.  It is reasonable to extend some of the conclusions of that work northward into BC, though prudent to remember that such correlations do not always indicate causality and that the correlations change over both space and time, requiring individual analyses in individual locations for the time period of interest.  With knowledge of these correlations and their causal mechanisms, however, the dependence of regional climate on long-period indicator signals allows for long-term predictability of these necessary variables for water resources management [2].  With additional forcing, as from global warming and its regional variations, we can expect the predictability of such variables as temperature and precipitation and their derivative impacts on freshwater resources in such regions to become more complex, at least until some trends can be detected in the changing signals and more local studies can be completed [3].

In 2008, a group of eminent hydrologists declared in the journal Science that "Stationarity is Dead" [4]:
"Stationarity - the idea that natural systems fluctuate within an unchanging envelope of variability - is a foundational concept that permeates training and practice in water-resource engineering...
"The stationarity assumption has long been compromised by human disturbances in river basins. Flood risk, water supply, and water quality are affected by water infrastructure, channel modifications, drainage works, and land-cover and land-use change. Two other (sometimes indistinguishable) challenges to stationarity have been externally forced, natural climate changes and low-frequency, internal variability (e.g., the Atlantic multidecadal oscillation) enhanced by the slow dynamics of the oceans and ice sheets [5, 6]. Planners have tools to adjust their analyses for known human disturbances within river basins, and justifiably or not, they generally have considered natural change and variability to be sufficiently small to allow stationarity-based design...
"Stationarity is dead because substantial anthropogenic change of Earth's climate is altering the means and extremes of precipitation, evapotranspiration, and rates of discharge of rivers [7, 8]. Warming augments atmospheric humidity and water transport. This increases precipitation, and possibly flood risk, where prevailing atmospheric water-vapor fluxes converge [9]... Glacial meltwater temporarily enhances water availability, but glacier and snow-pack losses diminish natural seasonal and interannual storage [10]."
Their reference numbers (2 - 7) have been converted to my own [5 - 10] and listed below for your ease of searching.  One common area in which "prevailing atmospheric water-vapor fluxes converge" is on the seaward side of mountain ranges, as in southern BC on the Pacific side of the Coast Range and Rocky Mountains.  BC also hosts massive glaciers subject to thinning and melting, and is anticipated to experience new extremes in precipitation volume and frequency.  Most specifically, the group borrowed results of the Intergovernmental Panel on Climate Change (IPCC) 4th Assessment Report (AR4), Contribution of Working Group II (WG2) regarding the impacts of anticipated climate change on freshwater runoff [11]:


We see that BC, and much of Canada, is expected to see generally greater runoff volumes with climate change, though additional factors such as earlier melting times in the year must also be taken into account.  An accompanying figure in another part of the IPCC AR4 WG2 report [12] indicates that forested areas in BC will actually increase in coverage, though some areas in this part of the Canadian boreal forest will change in type (likely from evergreen to deciduous) and the southernmost fringes might dry out and disappear altogether.  The evidence of insect infestation and degraded forest area is already well known in the American Rockies and is creeping northward into BC and Alberta, an indication that the health of the forest ecosystem is already under stress and a harbinger of forest succession, potentially including more widespread forest fires.  The impacts of these changes could devastate the inherent ecological services of the region, including biodiversity in the boreal and coastal temperate rainforest ecosystems, carbon sequestration in the forest areas, and water quality in downstream areas.

So what do these climate changes mean for water supplies and utility operations in the province? In snow-dominated areas, including some watersheds originating in the Coast Range but primarily those in the Rocky Mountains, Barnett et al. (2005) provided a precise summary of the anticipated impacts [10]:
"In a warmer world, less winter precipitation falls as snow and the melting of winter snow occurs earlier in spring. Even without any changes in precipitation intensity, both of these effects lead to a shift in peak river runoff to winter and early spring, away from summer and autumn... Where storage capacities are not sufficient, much of the winter runoff will immediately be lost to the oceans."
On the Columbia River, we might not expect any missed winter and spring runoff to be "lost" given the massive storage capacity of so many dams downstream in the US.  In other major basins, such as the Yukon headwaters and on the Peace River, the volume of water is so abundant that the infrastructure seems oriented more on hydropower production and less on freshwater storage, such that the water is generally passed downstream in run-of-the-river project locations.  These projects may very well meet the needs of BC residents for the immediate future, but in the long term I can envision calls from outsiders to build and fill additional storage capacity for eventual transfer to the province's northeastern prairie areas and to its neighbors, including Alberta to the east and the US states to the south.  These areas are already water-stressed, and the anticipated concentrations of population and industry there over the next century will only increase human pressure on already-scarce resources.

BC physiography, credit Wikimedia Commons
Another part of BC is dominated instead by temperate rainforest or boreal forest, where snowmelt does not necessarily dominate the seasonal cycles of freshwater runoff.  In this case, it is instructive to look closely at the physiography of the province, as show in the figure at right.  In the southern province, on the western (Pacific) side of the Coast Range, temperate rainforests will likely see heavier rainfall in more frequent winter storms.  On the eastern side of the Coast Range, the rain-shadow effect already present will likely persist with some moderation by the spill-over of storms making landfall and moving east from the Pacific Ocean.  It is thus possible that the interior of the province will see a growing contribution in streamflows from the Coast Range, but not likely as great as the overall impact of precipitation increases on the Pacific side of the continental divide along the spine of the Rockies.  There, and especially in the northern province that seems dominated by a solid mountainous region, summer storms may become more intense and frequent, and winter storms may leave deeper snowpack for the melting season.  In terms of power production, the annual peak load is likely to increase as residents and businesses increase their uses of heating in the winter and cooling in the summer, so demand may increase overall while supply increases only in the spring melt season, and in fact is likely to diminish slightly in the autumn low-flow season.  Because of the mixed portfolio of hydropower based on both reservoir and run-of-the-river generating stations, BC Hydro is well-situated to adapt and account for climate-related changes in the magnitude and timing of peak power demands across the province with a variety of supply generation options.

Conceptual design of the proposed BC Hydro Peace River Site C project
Finally, the northeastern portion of BC lies in the rain-shadow of the Rocky Mountains and constitutes a portion of the Canadian Prairie of which Alberta, BC's provincial neighbor to the east, remains the country's exemplar. This is the region through which the Peace River exits the provincial interior, eventually joining the Mackenzie River on its way to the Arctic Ocean.  An apparent focal point of controversy between BC Hydro, the First Nations, provincial neighbors, extractive industries and conservationists over a large area is BC Hydro's planned Site C dam and hydropower project, officially known as the "Site C Clean Energy Project." BC Hydro proposes to construct a 60 m earth-fill dam, creating a reservoir 83 km long on the Peace River at an average width of 2-3x that of the natural river.  This means the flooding of ~5,340 hectares of land, including more than 3,000 hectares of wildlife habitats, heritage sites, and prime agricultural land.  Site C would be the third dam in a cascade along the Peace River, below the first at W.A.C. Bennett Dam (more details above) and the second at Peace Canyon Dam completed in 1980.  With a recent renewal of interest in the provincial government to see the newest project move forward, BC Hydro plans for Site C to be operating at its 900 MW design capacity by 2020, litigation and permitting challenges notwithstanding.  What is not made clear in the available information on Site C, located as it is planned on the edge of the BC/Alberta prairie region, is how much of the water stored and energy generated at the new facility would be put to use for petroleum extraction from oil sands and shale formations in that region, a practice that we know now has significant detrimental effects on water and environmental quality.

Earlier this week, the Pew Environment Group (PEG) released a landmark report entitled "A Forest of Blue: Canada's Boreal Forest, the World's Waterkeeper." It's no surprise to me that the connections between forests and water resources are finally being explored in detail.  I'll post an article soon on some of that research that I've done recently, as well as another article with an overview on the PEG report and its connections to a book that I've been reading (Vanishing Halo: Saving the Boreal Forest).  There is hope that the ecological wealth of the boreal forests that still stand in North America and Eurasia will be recognized and preserved for the sake of everyone, not just those who live there. Where the boreal forest band crosses northern British Columbia, and where other forests occur in the southern portions of the province, it is incumbent on the provincial and national governments and the people of Canada, the US, and conservation groups to work together to husband the forest and its resources, including its abundant freshwater, in a responsible manner.

ResearchBlogging.orgReferences

[1] Hamlet, A., and D. Lettenmaier, 1999: "Columbia River Streamflow Forecasting Based on ENSO and PDO Climate Signals." Journal of Water Resources Planning and Management, v. 125, no. 6, pp. 333 - 341. DOI: 10.1061/(ASCE)0733-9496(1999)125:6(333)

[2] Hamlet, A.F., and D.P. Lettenmaier, 2000: "Long-range climate forecasting and its use for water management in the Pacific Northwest region of North America." Journal of Hydroinformatics, v. 2, no. 3, pp. 163 - 182.

[3] Vörösmarty, C.J., P. Green, J. Salisbury, and R.B. Lammers, 2000: "Global Water Resources: Vulnerability from Climate Change and Population Growth." Science, v. 289, no. 5477, pp. 284 - 288. DOI: 10.1126/science.289.5477.284

[4] Milly, P., J. Betancourt, M. Falkenmark, R. Hirsch, Z. Kundzewicz, D. Lettenmaier, and R. Stouffer, 2008: "Stationarity Is Dead: Whither Water Management?" Science, v. 319, no. 5863, pp. 573 - 574. DOI: 10.1126/science.1151915

[5] Webb, R.H., and J.L. Betancourt, 1992: "Climatic variability and flood frequency of the Santa Cruz River, Pima County, Arizona." U.S. Geological Survey, Water-Supply Paper no. 2379, 40 pp. Available in djvu.

[6] Woodhouse, C., S. Gray, and D. Meko, 2006: "Updated streamflow reconstructions for the Upper Colorado River Basin." Water Resources Research, v. 42, no. 5. DOI: 10.1029/2005WR004455

[7] IPCC, 2007: "Summary for Policymakers." Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller, Eds., Cambridge University Press, Cambridge, UK, and New York, NY, USA, pp. 1 - 18. Available in html and pdf.

[8] IPCC, 2007: "Summary for Policymakers." Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, UK, pp. 7 - 22. Available in html and pdf.

[9] Held, I., and B. Soden, 2006: "Robust Responses of the Hydrological Cycle to Global Warming." Journal of Climate, v. 19, no. 21, pp. 5686 - 5699. DOI: 10.1175/JCLI3990.1

[10] Barnett, T., J. Adam, and D. Lettenmaier, 2005: "Potential impacts of a warming climate on water availability in snow-dominated regions." Nature, v. 438, no. 7066, pp. 303 - 309. DOI: 10.1038/nature04141

[11] Kundzewicz, Z.W., L.J. Mata, N.W. Arnell, P. Döll, P. Kabat, B. Jiménez, K.A. Miller, T. Oki, Z. Sen, and I.A. Shiklomanov, 2007: "Freshwater resources and their management." Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, UK, pp. 173-210. Available in html and pdf.

[12] Fischlin, A., G.F. Midgley, J.T. Price, R. Leemans, B. Gopal, C. Turley, M.D.A. Rounsevell, O.P. Dube, J. Tarazona, and A.A. Velichko, 2007: "Ecosystems, their properties, goods, and services." Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, pp. 211-272. Available in html and pdf.

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