Environmental Assessment
Volume B-3.8
Mine
Hydrology
Ambatovy Project
95
January 2006
The key indicators of change due to the project are flows, water levels, sediment
concentrations and channel morphology. These changes may also have an effect
on water quality, fish health, vegetation (wetlands), and socio-economic
components of the project.
The Key Questions for the hydrology surrounding the mine are:
Key Question H-1
What Effect Will the Mine Have on Flows and
Water Levels in Water Bodies?
Key Question H-2
What Effect Will the Mine Have on Sediment
Levels in Water Bodies?
Key Question H-3
What Effect Will the Mine Have on Torotorofotsy
Wetlands Hydrology and Sediment Loading?
The linkages between project activities, environmental changes, key questions,
and assessment results are shown in Volume H, Appendix 9.
3.8.5
Impact Assessment
3.8.5.1 Impact Pathway Evaluation
Project activities during construction, operations and closure may result in the
following:
•
changes in flows and water levels in receiving water bodies;
•
changes in sediment levels; and
•
subsequent effects on the hydrology and sediment loading of the
Torotorofotsy Wetlands.
During construction there will be disturbance to the landscape as a result of site
clearing and the development of infrastructure. Surface runoff characteristics
and natural drainage patterns will be affected. Landscape disturbance, along with
the exposure of soil to erosion, may increase sediment yield and transport to
receiving water bodies.
During operations, the mine area runoff will be collected in detention and
clarification ponds prior to discharge to the receiving environment. The ponds
will be used as settling basins to limit the discharge and transport of suspended
sediment to downstream reaches. Increases in surface runoff and decreases in
