DISCUSSION PAPER FEEDBACK FORM
Discussion Paper Title:
What are the interactions between unconventional gas resources and water resources?
Input quality and quantity requirements and water treatment needs and impacts.
1) How useful was this Discussion Paper to you? Please select.
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2) How easy was this Discussion Paper to read and understand? Please select.
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3) To what extent do you agree with the accuracy of the Discussion Paper? Please select.
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4) Are there any topics that were omitted that you would like to see included in future versions?
Please list.
In the scope of the Hydraulic Fracturing Review, this Discussion Paper on water was mandated to
conduct a comprehensive evaluation of the potential risks to surface water supplies due to location
of a hydraulic fracturing operation. As it stands, the Discusion Paper does not meet this mandate.
In order to do so the following issues need to be corrected:
The conclusion in the Discussion Paper that “there is sufficient capacity for Nova Scotia to maintain
its current water use” (pg. 9) is unfounded; it should be replaced with a conclusion that reflects the
need for a scientifically valid mass-balance analysis that takes into account watershed sizes found
in Nova Scotia. Without such water budget analyses, no valid water quantity assessments for shale
gas development can be made.
Here are some examples of incorrect mass balance analyses in the Discussion Paper:
1. Page 9. Here the Discussion Paper makes an assessment that “the total amount of water
needed for shale gas development is generally small in the Canadian hydrologic context”.
This may be true, but the Canadian hydrologic context is inconsequential. First, it is entirely
unclear what a “Canadian hydrologic context” might be, as there is a large variability in
runoff rates across the country. This statement is also without meaning because the
amount of available water in a watershed depends on both mean annual runoff rates and
the size of the watershed. For very small watersheds the total amount of water needed for
shale gas extraction is likely to be proportionately very large, as can be proven by mass
balance calculations. Further, it is well-established in the scientific literature that smaller
watersheds are more sensitive than large watersheds to water withdrawals as is made clear
in an Environment Canada (2004) report on threats to water availability in Canada (2004):
“Manufacturing withdrawals from smaller tributaries and rivers could have more severe ecological
impacts. The hydrologic characteristics of smaller rivers are such that they exhibit large fluctuations
of high and low flows, and the summer low flow period is critical in smaller watersheds in that there
may not be sufficient water available to meet the demands.”
2. Page 9. The Discussion Paper here uses comparisons of water delivery to Halifax without
scaling by watershed size. Once again, mass balance and water budgets need to take
watershed size into account to be correct, which these comparisons do not.
3. Page 9. The mean annual flow St. John River is used as a basis for comparison to establish
the sustainability shale gas withdrawal rates in Nova Scotia. The problem with this
comparison is that the watershed area for the St. John River is 54,986 km2 – bigger than the
entire province of Nova Scotia (54,400 km2). In contrast, the largest watershed in the
province of Nova Scotia is 2,481 km2. Further, 24,791 km2 of the province, almost half
(46%), is covered by small watersheds – less than 200 km2 in area. This means that of all
the water that flows in the province, almost half would travel only in small rivers that are
especially sensitive to water extraction. Potential impacts to our small watersheds would
not be insignificant - the water that flows in our small coastal watersheds is needed to
support our coastal communities, and our manufacturing, agriculture and tourism
industries, among others.
I conducted some preliminary mass balance calculations, taking watershed size into
account, and assuming similar mean annual runoff rates of the St. John River basin (this is
an assumption that can only be used for back of the envelope calculations such as these,
but should not be used for planning purposes; instead, regional water budgets must be
established). Assuming a mid-range water withdrawal rate per well (10,000 m3/yr) and
assuming 1000 wells in a watershed, the annual water need for shale gas extraction would
be 10,000,000 m3/yr. In comparison, this water need is equivalent to approximately 24% of
the total mean annual flow (i.e., all renewable water available in the watershed) for the
Bass River, and approximately 11-14% of the total annual flow for the Debert, Nappan and
Economy Rivers. If we assume that all the water extraction occurred during the summer
months (July, August, and September), and using mean monthly runoff rates, normalized by
watershed size from the St. John River, then the projected water demands for this shale gas
scenario would equal 80-100% of the mean runoff from July-September for the Economy,
Nappan and Debert Rivers, and 181% of the mean summer runoff for the Bass River.
Obviously, for this scenario, shale gas extraction would be neither feasible nor sustainable
in these particular watersheds without large-scale inter-basin water transfers and
concomitant environmental effects.
These preliminary calculations show that at least some watersheds may not have enough
water for shale gas demands, as defined by the above scenario. A regional-scale scientific
investigation of the water budgets for the watersheds of Nova Scotia and the development
of more precise shale gas development scenarios are essential before any valid statements
of the sustainability or feasibility of water withdrawals can be made. Without this, it is not
possible to evaluate the potential risks to our surface water supplies due to location of a
hydraulic fracturing operation, as is mandated in the scope of the Hydraulic Fracking
Review.
4. On page 21, the paper identifies that regulatory agencies will need to monitor the effects of
water withdrawals. However, the paper is missing a discussion of the ability of regulators to
monitor these effects. Specifically, Nova Scotia has a low density of water monitoring
stations compared to other provinces and states, and these water monitoring stations are
not located in the most highly stressed watersheds (Sterling et al., 2014). Therefore the
ability of regulators to detect impacts to water resources from shale gas extraction is
limited. As a result, a comprehensive regional strategic environmental impact assessment
of the possible cumulative effects of shale gas extraction is needed before development of
this industry is permitted.
Other items missing:
5. This Discussion Paper uses obsolete figures from an early draft of our paper Sterling et al.,
2014. This must be fixed: the final Discussion Paper needs to use the final figures from the
accepted paper in Journal of Hydrology. Also, the citation needs to be updated. Please
contact me and I would happy to provide these to you (Shannon.sterling@dal.ca).
6. The Discussion Paper is missing a section on information gaps. This is particularly critical
with regards to any evaluation of potential impacts to water quantity from shale gas
development. As outlined above, regional-scale water budgets have not yet been done for
Nova Scotia; without this information on water budgets, it is not possible to assess the
impact of shale gas development on water availability. Without water budget information,
valid statements on the potential feasibility or sustainability of fracking in Nova Scotia with
regards to water quantity cannot be made.
7. The conclusions made in the Discussion Paper on pgs. 3 and 4 that human land use and acid
rock drainage are the predominant threats to water quality for Nova Scotia, and that the
majority of threats to water quality arise from land use activities. These conclusions are
inconsistent with the conclusions of our paper (Sterling et al., 2014). The approach used in
the NSWAP does not permit comparisons of relative stressors, and therefore these
conclusions need to be changed. For more information see the discussion section of Sterling
et al., 2014.
8. Page 7. Several important surface water quality issues in Nova Scotia are missing here, such
as chronic acidification and eutrophication. The water quality issue list needs to be
supported by references to the scientific literature.
9. Page 9. Here it needs to be mentioned that, in addition to aquifers, surface water bodies
can also be overdrawn.
10. A discussion of the role of regional-scale studies in evaluating impacts of shale gas
development is missing (e.g., see Rahm and Riha 2012). The lack of regional-scale
approaches has been a major criticism of environmental impact assessments of shale gas
extraction (Rahm and Riha, 2012), because this type of development occurs in a distributed
manner across regional landscapes and can expand quickly. For example, in PA, from 20072012, the number of Marcellus Shale gas wells grew from a handful to around 4000, spread
over about 30 counties (roughly 50,000 km2). Recent studies have established that regionalscale / provincial scale planning of water resources is essential before committing to major
water withdrawal activities at the provincial scale, as opposed to permitting on a case-bycase basis (e.g., CEQ 1997, Kay et al., 2010; Zhao et al., 2009; Cooper and Sheate, 2004,
Spaling and Smit, 1993). This regional-scale planning is especially critical for Nova Scotia
given its large number of sensitive small watersheds.
5) Are there any questions that you would like to see addressed? Please list.
1. Who will conduct the regional-scale water management plans that are needed to
determine whether the water resources of Nova Scotia are adequate to support
sustainable use under shale gas development? Who will pay for these assessments?
2. How much water withdrawal as needed for shale gas development is too much? 25% of
mean annual flow? 5% of mean annual flow? 20% of summer flow?
3. Which watersheds in Nova Scotia have a large enough mean annual flow to support
shale gas development? Which do not? Should the province support inter-basin water
transfers? Under what conditions?
4. How will shale gas water extractions be managed under winter conditions when much
of the surface water may be frozen? During winter months, there will be less available
water, and therefore the available water in the watersheds could be much lower. If
water extractions were permitted in these conditions, then it is more likely that the
surface water resources may be overdrawn.
References
Cooper, L.M., Sheate, W.R., 2004. Integrating cumulative effects assessment into UK strategic planning:
implications of the European Union SEA Directive. Impact Assess. Project Appraisal 22 (5), 5–16
Council on Environmental Quality (CEQ), 1997. Considering Cumulative Effects Under the National
Environmental
Policy
Act.
U.S.
Department
of
Energy,
Washington,
DC
http://ceq.hss.doe.gov/nepa/ccenepa/ccenepa.htm.
Environment Canada. 2004. Threats to Water Availability in Canada. National Water Research Institute,
Burlington, Ontario. NWRI Scientific Assessment Report Series No. 3 and ACSD Science Assessment Series
No. 1. 128 p.
Kay, D., Geisler, C., Stedman, R.C., 2010.In: What is Cumulative Impact Assessment and Why Does it Matter?
CaRDI Research & Policy Brief Series Issue No. 37. Community and Regional Development Institute, Cornell
University,
Ithaca,
NY
http://devsoc.cals.cornell.edu/cals/devsoc/outreach/cardi/publications/loader.cfm?csModule=security/getf
ile&PageID=930728.
Rahm, B.G., S.J. Riha, 2012. Toward strategic management of shale gas development: regional, collective
impacts on water resources. Environmental Science and Policy 17, 12-23. DOI: 10.1016/j.envsci.2011.12.004
Spaling, H., Smit, B., 1993. Cumulative environmental change: conceptual frameworks, evaluation
approaches, and institutional perspectives. Environ. Manage. 17 (5), 587–600.
Sterling, S., K. Garroway, G. Yue, S. Ambrose, P. Horne, G. Kennedy, 2014. A new watershed assessment
framework for Nova Scotia: a multiple stressor exposure-based approach for regions without a dense
network of monitoring stations. Journal of Hydrology (in review).
Zhao, M., Becker, D.R., Kilgore, M.A., 2009.In: The Integration of Cumulative Environmental Impact
Assessments and State Environmental Review Frameworks. Staff Paper Series No. 201. Department of Forest
Resources, College of Food, Agriculture and Natural Resource Sciences, University of Minnesota, St Paul, MN
http://www.forestry.umn.edu/prod/groups/cfans/@pub/@cfans/@forestry/documents/asset/cfans_asset_
184736.pdf.
6) Would you like to receive updates about the Hydraulic Fracturing review and notices about the
release of future papers? Please select: Yes No
Name: Shannon Sterling, PhD (Duke), Department of Earth Sciences, Dalhousie University
Email: Shannon.sterling@dal.ca