The Delta begins in the panhandle where the Angola River dumps water and sediment into the wetlands. This sediment has become of particular concern in recent years as more and more discussion of building dams has arisen. The need for water in this geographic region cannot be understated. The Okavango sits atop the arid Kalahari Desert.
 |
This image shows the massive Kalahari Desert directly below the Okavango Delta.
|
Due to this need for water in the surrounding areas many groups would like to dam the Angola River in an effort to keep that water from ever reaching the Okavango. The Institute of Environmental Engineering recently monitored the flow of water and sediment in an attempt to understand how damming the river could effect the delta. They found that the channels flow through a thick papyrus belt which helps to filter out the sediment. Flow velocities are decreased and aggradation of the channels are caused. Most of the sediment is a fine sand and is deposited onto the bottoms of the channels in a ripple like pattern.
 |
| This image displays the pattern in which the sand forms on channel bottoms. |
This causes the channel bottoms to rise above the surrounding land. The water is held in the channel by vegetation until there is a gap. When the vegetation gives way a new channel will form and more sediment will be deposited. This is what creates the alluvial fan shape of the Delta. Should the Delta be dammed upstream this shape could be in jeopardy. If when dammed up, sediment is lost the Delta could become one large channel or an end-lagoon system. The sediment carried by the waters is really what creates this vast wetland and without it the Delta could be lost.
Work Cited: http://www.northsouth.ethz.ch/news/past_events/past_events_zil/annualconference06/posterexhibition/Milzow.pdf
