Environmental Assessment
Volume E-3.10
Tailings Facility
Water Quality
Ambatovy Project
122
January 2006
Concentrations of substances (except copper and nickel) in bottom sediments are
below the corresponding Canadian and US guideline values. However, higher
concentrations of copper and nickel in bottom sediments relative to the
corresponding guideline values should be treated with caution since derivation of
these guidelines did not consider local ecological conditions in Madagascar.
Additional details on baseline conditions for sediment quality are provided in
Volume I, Appendix 9.1.
3.10.4 Issue Scoping
Surface water concerns of stakeholders and regulators are focused on potential
changes to water uses. Downstream water users and aquatic life may be
adversely affected by changes in water and sediment quality associated with the
construction, operations and closure activities of the tailings facility. In the water
basins surrounding the project, the major water uses include domestic,
agricultural irrigation (mainly rice paddies) and ecological sustenance.
The following aspects of the project in the tailings facility area could potentially
affect water and sediment quality of nearby surface watercourses:
•
disturbance of watercourses during the construction of the facility;
•
diversion and disruption of natural drainages;
•
accidental releases or spills;
•
seepage from the tailings facility into downstream watercourses;
•
overtopping of tailings impoundment during extreme storm events; and
•
runoff from the reclaimed tailings area.
The linkages between project activities and effects on water and sediment quality
are shown in Figure 9-14, Volume H, Appendix 9.
The key question for water and sediment quality is:
Key Question SWQ-1 What Effect Will the Tailings Facility Have on
Water and Sediment Quality?
3.10.5 Impact Assessment
The proposed tailings facility is located in the upper watersheds of three parallel
tributaries to the Ambolona River. The facility will be developed gradually and
reclamation will occur progressively. A water management pond will be
