Environmental Assessment
Volume C-3.6
Slurry Pipeline
Hydrology
Ambatovy Project
49
January 2006
3.6
SURFACE WATER HYDROLOGY
3.6.1
Introduction
Construction of the slurry pipeline will involve clearing and excavation along the
pipeline right-of-way as well as disturbance to the streambed at most watercourse
crossing locations. Water withdrawal and disposal will also be required for
hydrostatic testing of the pipeline. Changes in runoff and sediment yield along
the right-of-way can be mitigated by erosion control measures and best
management practices. Channel disturbance during construction may affect flow
velocities and associated water levels, and may also result in increased suspended
sediment in downstream reaches.
Stream morphology, discharge measurements, and cross-sectional surveys were
conducted to help characterize baseline conditions along the pipeline route
(Volume I, Appendix 8.1). The available baseline information is summarized in
the following sections for evaluation of potential effects of the Ambatovy Project
(the project) on streamflow and sediment yield.
The local study area (LSA) for the slurry pipeline is shown in Volume A,
Figure 7.2-2. The study area includes a 1 km buffer either side of the route,
along the length of the corridor.
3.6.2
Baseline Summary
3.6.2.1 Introduction
Baseline conditions along the slurry pipeline route were characterized by
analyzing available climate and hydrologic (streamflow) data from the mine area
and the coastal plant and port areas. A summary of the climate and hydrology
baseline study is provided in the following sections. Details can be found in
Volume I, Appendix 8.1.
3.6.2.2 Methods
Information on Madagascar’s climate was obtained primarily from Chaperon et
al. (1993). Climate information was also obtained from the World
Meteorological Organization, from rainfall stations at regional railway stations,
and from the Madagascar Ministry of Public Works and Transport, Meteorology
Branch.
