Der Savuti-Sumpf
English: The Okavango Delta is an oasis in Africa’s Kalahari Desert. When the Kalahari reaches its driest phase—when plants wither and animals hunt for drinking water—the Okavango provides it. But starting in 2009, the delta provided more than usual, and excess water overflowed into other land depressions in the region. One of the waterways linked to the Okavango Delta is the Savuti River, roughly 80 kilometers (50 miles) northeast of the sprawling inland delta. On May 26, 2012, the Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite captured this natural-color image of water flowing through the Savuti River and into Savuti Swamp. The swamp sits inside the larger Mababe Depression within Botswana’s Chobe National Park. Unlike the seasonal flooding that affects the Okavango Delta every year, the flooding in 2012 was unusual. Guido van Langenhove of Hydrological Services Namibia characterized it as “an exceptional hyrological event.” The rains that fill the Okavango don’t actually fall over the delta itself. Instead, the rains fall in the Angolan Highlands and travel about 450 kilometers (280 miles) through meandering rivers and over an extremely shallow gradient. As a result, rains that typically fall over Angola from October through March don’t usually reach the bottom of the Okavango Delta until July. But in May 2012, water had already arrived in the Okavango and was overflowing into other waterways such as the Savuti River. “The Okavango Delta has had record floods for a few years now,” said Frank Eckardt of the University of Cape Town. “We have seen the Boteti River in flood since 2009, and have also seen water in Lake Xau, southeast of the delta. Now we are seeing water in the Selinda Channel, heading into the Mababe Depression northeast of the delta. Some of these depressions only fill with water after decades of dryness.” Van Langenhove concurs, remarking that the flooding had reactivated waterways in the region regarded by some observers as “fossil rivers.” NASA Earth Observatory image by Jesse Allen and Robert Simmon, using EO-1 ALI data provided courtesy of the NASA EO-1 team. Caption by Michon Scott with information from Frank Eckardt, University of Cape Town; and Guido van Langenhove, Hydrological Services Namibia. Afrikaans: Die Okawangodelta is 'n oase in die Kalahariwoestyn, wat die woestyn in die droëseisoen voed wanneer plante verwelk en diere na water soek. Vanaf 2009 het die delta egter meer as die gewone gelewer en oortollige water het na ander nabye laagtes oorgevloei. Een van die waterweë wat aan die delta gekoppel is, is die Sawoetirivier wat tot sowat 80 km (50 myl) noordoos van die uitgebreide binnelandse delta strek. Op 26 Mei 2012 het die Gevorderde Landafbeelder op NASA se Aardobservasie-1-satelliet (d.i. EO-1 ALI) hierdie beeld in natuurlike kleur vasgevang van water wat via die Sawoetirivier noordwaarts na die Sawoetimoeras vloei. Die moeras is geleë binne die Mababe-laagte van Botswana se Nasionale Chobewildtuin. Die oorvloei van 2012 was anders as die tipiese seisoensvloede wat die delta jaarliks beleef, en Guido van Langenhove van Namibië se Hidrologiese Dienste het dit beskryf as “'n buitengewone hidrologiese gebeurtenis.” Die reëns wat die Okawango vul, val eintlik nie oor die delta self nie, maar oor die Angolese hooglande en word oor sowat 450 km (280 myl) afgevoer via meanderende riviere en oor 'n baie effense gradiënt. Gevolglik bereik die reënwater wat tipies van Oktober tot Maart in Angola val, gewoonlik nie die bekken van die Okawangodelta voor Julie nie. In Mei 2012 het water egter reeds die Okawango bereik en het na ander waterweë soos die Sawoetirivier oorgevloei. “Die Okawangodelta ervaar nou reeds 'n paar jaar lank rekordvloede,” het Frank Eckardt van die Universiteit van Kaapstad gesê. “Ons het gevind dat die Botetirivier in vloed is sedert 2009, en het ook water in Xau-meer, suidoos van die delta, opgemerk. Verder sien ons nou water in die Selindakanaal, op pad na die Mababe-laagte, noordoos van die delta. Sommige van hierdie laagtes word net na dekadelange droogte met water gevul.” Van Langenhove beaam dat die vloede waterweë in die streek herstel het wat deur sommige waarnemers as “fossielriviere” gereken is. Hierdie beeld van NASA se Aardobservatorium is deur Jesse Allen en Robert Simmon verskaf, met EO-1 ALI-data wat goedgunstig deur NASA se EO-1-span verleen is. Byskrifte is deur Michon Scott met inligting verskaf deur Frank Eckardt, Universiteit van Kaapstad; en Guido van Langenhove, Hidrologiese dienste Namibië.