Nangoma Cave (Upper entrance)
The NCS is located near to Nandembo village, which can be reached by a 4WD vehicle from Kipatimu during the dry season (June to December). It is possible to park the car immediately at the steep entrance doline of Nangoma cave. Since the 1994 speleological campaign and the subsequent publications the Nandembo Cave System got a little bit more known in the public and the number of visitors rised to the benefit of the local people. While in 1994 the entrance doline was completely filled by a dense thicket a walkable footpath down to the cave was present in 2000. Most of the visitors just take a short walk in the impressive Nangoma cave and do not explore the rest of the extensive cave system due to lack of equipment. A significant decrease of the bat colony living in Nangoma cave has been stated during the 2000 project and indicates a simultaneous growth of visitors frequencies. Today the number of bats is reduced to approximately 50 % of the 1994 population.
Nandembo Cave System
The most important cave of the Matumbi Hills is the Nandembo Cave System (NCS) at 8°30'38’’ S - 038°53'00'’ E and at an elevation of about 430 m a.s.l. (Nangoma entrance). Its passage length of 7.510 m makes it the 15th longest cave currently known in Africa and it is the longest known cave of Tanzania. The NCS comprises the Nangoma cave, the Nakitara cave, the Nampulu (Kinanguana) pit, the Nakinduguyu sinkhole and the Anduli cave, all of which are interconnected subterraneously. Kiongoro sinkhole is connected hydrologically to Nangoma cave but cannot be passed. The Anduli entrance is identical to the so-called ..Nduli cave“ reported by Anon. (1911). This entrance is the resurgence of all the water drained by the cave system. The sump at Anduli entrance is situated at an elevation of 316 m a.s.l. giving the whole NCS an overall depth of -114 m. Thus, the NCS is also the deepest cave of Tanzania. The NCS has been surveyed to 5.390 m in 1994. The 1995 project pushed the length to 7.5.10 m.
The entrance doline of Nangoma has a diameter of about 70 by 100 metres. At the SE rim of the doline the cliff exhibits crossbedded and thin layers of sandy limestone belonging to the Matumbi beds. To the SE the impressive 50 m wide and up to 12 m high upper entrance of Nangoma opens at the bottom of the doline. A gallery of the same dimensions descends to a huge passage. At the left part of the entrance a pool of stagnant water can be reached, which is most likely connected by underwater passages to Kiongoro sinkhole about 100 m away. Proceeding straight down into the main cave bat guano covered rimstone pools guide the way down the deepest point of Nangoma where a hole in the floor leads down to a small streamlet, which is in average 2 m wide and 3m high. This streamlet makes connection to the Naktitara cave. The middle part of Nangoma cave ascends a guano covered slope cut by an archaeological trial dig by the Dar-es-Salaam Antiquities unit. On the right hand side there are two massive Stalagmite columns having the shape of African drums (...Nangoma"), which gave the name to the cave. The ongoing passage gradually diminishes in size, passes a ceiling drop and a subsequent 15 m wide and 1 m high crawl covered with dry powdered bat guano, but soon the conduit becomes higher and gets light from the cave’s lower entrance. The whole through passage of Nangoma has a length of 356 m. Nangoma has been used as a shelter for the Matumbi people during war time. Remnants of wooden structures, old pottery and the relicts of a wali at the lower entrance give evidence to the former use. Pottery has been collected from inside the cave by Mr. Moh. Chidoli (regional cultural officer). A large bat colony roosts in Nangoma cave. The number of undetermined bats have estimated to be about 1 million in July 1994. In August 2000 the population was less than 500.000 individuals. Nangoma is a representative of the huge fossil type of caves described under a) above. It is insofar a special case because it has been reactivated by a recent phase of karstification that led to the creation of a deeper active level of small waterfilled passages. Walking down from the lower entrance of Nangoma the inconspicuous entrance (1 m. wide and 2,5 m high) of Nakitara is reached in a narrow collapsed gorge. Nakitara is a part of the dry niveau of the NCS. The squeezy entrance leads into a maze of joint controlled passages. This network finally reaches a 5 m deep drop (caused by an intersected sandstone layer between the limestone beds) into a 200 m long, 6 m high and up to 20 m wide chamber. The chamber closes down to a short series of dry sandy crawls that pass the 10 m deep Nampulu daylight pitch. The subsequent Rimstone Inlet" is an active gallery that drains a small water stream to the SE. Rimstone pools on the floor give the name to this passage, which is clearly joint controlled. With the exception of several short narrow parts the “Rimstone Inlet" has an average size of 2,5 m by 5 m and progress is fairly easy. Less soluable sandstone layers often project far into the passage where the karstification cut through several layers of interbedded limestones and sandstones creating cross-sections of quite irregular shape. The Sicilian Inlet", surveyed for more than 1.700 m by the Italian party of the 1995 project and leading back in the direction of Nangoma, branches off from the Rimstone Inlet" with a 4 m climb (rope still attached). It is a partly very wet and sportive series of rift passages and the second active water inlet of the NCS. Finally, the unified Rimstone Inlet” and ..Sicilian Inlet” meets the main collector of the NCS that creates a 3 km long streamway between the Nakinduguyu sinkhole and the Anduli entrance. The exciting ...Whirlpool Inlet", coming from Nakinduguyu, is the third water inlet to the NCS. It consists of a sportive wet but walkable passage and offers excellent caving to the speleologist. A small sump appears to be connected to the ,Sicilian Inlet" series. The main collector leading to Anduli is partly a very large conduit sized 20 by 20 m filled with up to 2 m deep water. The subterranean river drained about 1 1/sec. in the dry season and water samples were tested by the Italian participants in 1995 (see annex 2). The direction of drainage of the young passages of the NCS (except Nangoma cave) is NW to SE. The water generally follows the dip of the limestone layers. The 10 m wide and 4 m high Anduli entrance slopes steeply down to the underground river, which disappears in a lower series of small rift passages and sumps soon. Some hundred metres further to the E from the Anduli entrance Liotoke sinkhole is located. Biospeleological observations in the NCS have been made by Mrs. I. Galletti (CIRS) (Galletti 1996). Spiders of the family Linphyiidae were found in the NCS (determination by A. Rohner). Several different species of bats occur even far inside in the NCS (e.g. Hipposideros vittatus PETERS 1852 in the ..Whirlpool Inlet"). A python snake has been seen inside Nakinduguyu sinkhole as well as an unknown species of a poisonous snake that accidentally fell into the Nampulu pitch. Furthermore, many insects, cave crickets and spiders (including amblipygii) are abundant, like in most of the other wet caves of the Matumbi Hills. The lakes of the cave host eels that have been washed into the cave during the wet season.