annexc - Newmont Mining Corporation
annexc - Newmont Mining Corporation
annexc - Newmont Mining Corporation
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Annex C4 – Water Resources Supplemental Information C4 - 1<br />
WATER RESOURCES SUPPLEMENTAL INFORMATION<br />
SURFACE WATER QUANTITY<br />
Pra River<br />
Using mean monthly flow data from the Hydrological Division of the Ministry of Works and<br />
Housing in Accra (SGS 2004d), the mean annual discharge for the Pra River at Ofoase-Praso<br />
(SW-27; 2,045 km 2 watershed area) is 12.5 cubic metres per second (m 3 /sec), with mean<br />
monthly flows shown on Table C4-1. Figure C4-1 contains a hydrograph and data for<br />
Pra River mean monthly total flows for the period of record (1960-1978 and 1991-1999) at<br />
SW-27.<br />
Mean monthly flows were estimated for the Pra River at Praso Kuma (located upstream of<br />
the Study Area near SW-21; 875 km 2 watershed area) using the area-ratio method and<br />
measurements for the Pra River at Ofoase-Praso discussed above. Mean monthly flow<br />
estimates for the Pra River at Praso Kuma are summarized in Table C4-2. Using these<br />
monthly estimates, mean annual flow for the Pra River at Praso Kuma is 5.4 m 3 /sec.<br />
TABLE C4-1<br />
Mean Monthly Flow Measured for Pra River at Ofoase-Praso Bridge (SW-27)<br />
(1960-1978 & 1991-1999)<br />
Month Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec<br />
Flow<br />
(meter3/second) 1.8 1.4 2.1 4.0 5.9 21.7 28.6 17.5 20.3 26.2 12.0 4.9<br />
Source: Hydrological Division of the Ministry of Works and Housing (Accra) in SGS 2004d.<br />
TABLE C4-2<br />
Mean Monthly Flow Calculated for Pra River at Praso Kuma (SW-21)<br />
Month Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec<br />
Flow<br />
(meter3/second) Source: SGS 2004g.<br />
0.77 0.60 0.90 1.71 2.52 9.29 12.24 7.49 8.69 11.21 5.14 2.10<br />
In April-May 2007, two continuous recording stream gauging stations were installed on the<br />
Pra River by Clear Creek Consultants (2008b) at SW-21 (PRA-1, upstream at Praso Kuma)<br />
and SW-27 (PRA-2, downstream at Ofoase-Praso). Figures C4-2 and C4-3 are<br />
hydrographs for these stations showing flow measured in February-June 2004 and May-<br />
December 2007. The following are selected flow data for these two Pra River stations<br />
(Clear Creek Consultants 2008b):<br />
Akyem Gold <strong>Mining</strong> Project November 2008 FINAL EIS
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