Groundwater Investigation in Eastern Caprivi 2006 DWA – BGR Cooperation by: Henry Beukes

Contents 1. Overview on work done 2. Individual site discussions 3. Comparisons 4. Conclusions and Recommendations 5. Word of Thanks

Overview Project started mid October and ended mid- December 2006 Seven boreholes were drilled (five successful) 689m in total drilled 403m useful

Locality Map

2.1 WW 200247 Drilled on 28/11/2006 Total meters drilled = 100m Basic Geology: Fine sand down to 50m Red fine sand to 80m Calcareous reddish white sand to 87m Clayey sand down to 90m Calcareous to clayey sand to 100m Step test of 4hr done and a 4 hour constant discharge test Step test was unreliable Note: Driller noted that borehole was dry

2.1 WW 200247

2.2 WW 200248 Drilled 29/11/2006 Total meters drilled = 103m Basic Geology: Unconsolidated sand down to 45m Calcretized sandstone to 77m Silcrete and sandstone down to 85m Alternating layers of silcrete and redish brown sandstone to 100m Basalt to 103m Five 1hour step tests conducted and a 24hour CD test Driller noted that borehole is very low yielding

2.2. WW 200248

2.3. WW 200254 Drilled 10/10/2006 Total meters drilled = 200m Basic Geology: Fine grained unconsolidated sand to 30m Clayey sand down to 60m Calcretized sandstone to 62 Alternating layers of clay and sandstone down to 120m Olive green clay between 120 and 130m Sand and sandstone down to 200m Four 1hr steps and a 72hr CD Test conducted Note that yield of borehole exceeded what drilled estimated

2.3 WW 200254

2.4. WW 200255 Drilled 21/10/2006 down to depth of 100m To be observation borehole for WW 200254 Basic Geology: Sand and calcrete down to 55m Some silcrete at 60m Sandstone down to 100m. Calcretized at 72 and 75m. Becomes reddish brown at depth Sandstone to final depth Five 1hr steps conducted Water is very saline

2.4. WW 200255

3. Comparisons In the report: Hand written data are less reliable than the use of level trolls Step tests are also relative less reliable, unless the borehole has been sufficiently developed

4. Conclusion and Recommendations The project was relatively successful Out of 7 borehole drilled, five can be used It is recommended that: - The bedrock be drilled deeper - Developing be supervised and only stopped if the borehole is sufficiently cleaned - Level trolls be used during test pumping Installation: Only three of the boreholes should be installed with monitoring devices The boreholes to be monitored are all drilled into the lower aquifer, i.e. WW 200254, WW 200247 and WW 200248.