This initial comparative environmental assessment aims to compare the potential environmental implications of the preferred dam sites that were identified during the screening process. Accordingly, this initial assessment compares the Vioolsdrif (at three different full supply levels) and Komsberg sites, although some of the specialist studies commissioned near the beginning of the study include consideration of the Boegeberg site, which was later discarded at the Options Assessment Screening Workshop. The study is restricted to the ecological, social and heritage issues. The effect of downstream flows and downstream impacts on the river and estuary are covered in the Specialist Report on the Environmental Flow Requirements - Riverine and the Specialist Report on the Determination of the Preliminary Ecological Reserve on a Rapid Level for the Orange River Estuary (LORMS Reports 400/8/1/P-07 and 08).