Environmental Assessment
Volume E-3.8
Tailings Facility
Hydrology
Ambatovy Project
65
January 2006
Meteorological Organization, from rainfall stations at regional railway stations,
and from the Madagascar Ministry of Public Works and Transport, Meteorology
Branch.
Site-specific streamflow data were collected between March 2004 and
March 2005 at four locations in the tailings area, including three stations along
the upper Amobolona River and one station on the Ivondro River. Discharge and
water level measurements were taken on a monthly basis by a team of
technicians in order to establish a rating curve for each location. Water levels
were recorded daily by local assistants and were used to derive a time series of
streamflow for each station. Daily water levels continue to be recorded at these
locations.
3.8.3.3 Results
The tailings facility is located near the major port of Toamasina. There are long-
term climate records available for Toamasina (1950 to 2004) from which mean
monthly and annual temperatures and precipitation have been derived.
Streamflow characteristics are based on results from the 2004 to 2005
hydrometric monitoring program.
Toamasina has a mean annual temperature of 24.6°C, with August being the
coldest month (21.7°C) and February being the warmest month (27.1°C). The
mean annual precipitation is about 3,300 mm (Table 3.8-1). March is the wettest
month (473 mm) and October is the driest month (115 mm). Historical records
suggest that the mean annual precipitation can vary from about 30% lower to
about 60 % higher. Estimates of maximum 24-hour rainfall amounts are
summarized in Table 3.8-2. Actual evapotranspiration for the tailings area is
estimated at 1,300 mm per year. Estimates of stream flow runoff are summarized
in Table 3.8-3.
Table 3.8-1 Mean Monthly Rainfall (mm) for Tailings Facility
Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Total
155 311 403 425 479 315 271 263 276 200 128 116 3343
Reference: Madagascar Ministry of Public Works and Transport, Meteorology Branch 2005.
