Tuesday, September 22, 2009

Will Lake Xau fill?

The flow of the Okavango’s waters down the Boteti River this year have been nothing short of spectacular, with the front of the flood approaching Rakops (over 200km from Maun) at present.

While predicting the future is fraught with all sorts of risks, it seems likely that it is a question of when, not if, the water will once again reach Lake Xau, which is the terminus for the Boteti. This assumes of course that Debswana will remove the structures they built previously to channel water into the Mopipi Dam, but given their recent track record (where they removed the bund blocking the Nhabe Channel leading to Lake Ngami), this looks likely. During wetter decades, Lake Xau was a substantial waterbody, and supported spectacular birdlife; the front cover of Smither’s 1964 Checklist of Birds of the Bechuanaland Protectorate depicts a Gull-billed Tern flighting over Lake Xau, and this is the type of rarity that may well turn up at the Lake again when it floods.

Since the Lake has been dry for several decades now, the lakebed has grassed over, and it is currently not unlike Lake Ngami was before the recent floods. Lake Xau is also similar to Lake Ngami in being a nutrient sink with rich soils that, when flooded, will result in nutrient-rich, eutrophic waters in an otherwise dry area. Lake Xau will almost certainly attract and support a diverse suite of waterbirds – in large numbers – when it finally floods. However, it will not be a destination for ‘armchair’ birders – the location is quite remote, there are no facilities in the area, and access will be difficult. For serious birdwatchers, though, it will be worth watching this Blog for updates on the status of the area.
View of the dry bed of Lake Xau (in distance) from Kedia Hill

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