1.0

Used as the rivers base data layer in the Saldanha/Sandveld systematic conservation assessment of freshwater biodiversity

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Methodology:

The GIS layer of origin is the 1:500 000 rivers data layer that DWAF has coded for

geomorphological zonations. CSIR subsequently used this layer to add information used to type rivers. During the process of geomorphic zonation, data attached to the 1:500 000 rivers were lost (e.g. reachcode and river names). To attach these data to the subsequent rivers with geomorphic zonations, we performed a series of grid overlays using a 100 m resolution pixel. This has created slight inaccuracies in river type and reach code information at river confluences of no more than 100 m. Where these inaccuracies created new river types, the in accurancies were corrected, but the majority of discrepancies were not changed. Thus, 0-100m segments of rivers may have the incorrect river type at confluences. For example, a non-perenial tributary flowing into a perennial mainstem may be coded as perennial just at its confluence. The approach and methods for typing and integrity are described in detail in the CAPE Saldanha/Sandveld freshwater report.

Available documentation:

CAPE Saldanha/Sandveld freshwater report

SANS 1878

FGDC-STD-001-1998