Pierre River Mine Project

WATER AENV SIRS 15 – 43
Section 12.1
ii. For the response to this question, see the response to AENV SIR 15ci.
iii. For the response to this question, see the response to AENV SIR 15ci.
Request 15d Shell describes corrective actions to include diverting water to vegetated areas to
trap sediments and mitigate water quality for other parameters of concern.
i. What are the other parameters of concern?
ii. What physiological and biogeochemical processes will the vegetated areas
employ to mitigate the water quality and how will Shell apply these processes
to other parameters of concern?
Response 15d i. Other parameters of concern include constituents that can be associated with
sediment particles suspended in water, including aluminum, cadmium,
chromium, copper, iron, lead, mercury, phosphorus, silver and zinc. These
also can include parameters noted in EPEA Approvals, water management
frameworks and other regulatory approvals, including biological oxygen
demand (BOD), nitrogen, phosphorus, toxic organic compounds, and total
dissolved solids (TDS).
Reference
ii. The vegetated areas of interest are typically wetlands, such as small
watercourses, bogs and marshes on the mine surface lease, although upland
vegetation in this area also provides many or all of the same functions to
some degree. Kadlec and Knight (1996) provide a rule of thumb that a
wetland removes about three-quarters of the incoming TSS, provided
incoming TSS has concentrations greater than 20 mg/L. Data collected by
Shell for releases of polishing pond water to Shelley Creek show that
wetlands in the Oil Sands Region are similarly effective at removing TSS.
Wetlands remove TSS via several pathways, including microscale and
macroscale deposition, inertial deposition on plant stems, and sediment
particles sticking to biofilms. Settling and filtration of suspended sediments
would remove compounds that are bound to these sediments, such as
aluminum, cadmium, chromium, copper, iron, lead, mercury, phosphorus,
silver and zinc. In addition, wetlands are known to significantly improve
water quality characteristics, such as BOD, nitrogen, phosphorus, toxic
organic compounds, and TDS. Advantages of wetlands are they are selfmaintaining
and they add no unnatural chemicals to the environment. They
also support a viable natural ecosystem.
Kadlec, R.H. and R.L. Knight. 1996. Treatment Wetlands. CRC Press/Lewis
Publishers. Boca Raton, Florida. 893 pp.
April 2010 Shell Canada Limited 12-3
CR029