Groundwater recharge generally decreases from north to south and from east to west across the Kunene River basin, although it is also influenced by localised favourable hydraulic properties of certain formations within the area that adds a complexity to the general trend.
High evaporation rates and the relatively steep relief in both the Upper and Lower Kunene resulting in rapid run-off results in a relatively low groundwater recharge. This ranges from around 250 mm/year to 170 mm/year in the Upper Kunene; from 170 mm/year to 80 mm/year in the Middle Kunene; and from 80 mm/year to zero in the Lower Kunene (LNEC 1996).
Groundwater recharge across the basin.
Source: AHT GROUP AG 2010 after LNEC 1996
( click to enlarge )
Despite the low rainfall and low recharge rates in the Lower Kunene a particular feature of the area is the abundance of springs in the tributaries to the Kunene. These springs are a result of rainwater which flows slowly downwards until it encounters the impermeable, massive bedrock (Burmeister and Partners 1998).
