Mara River

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The Mara River in Kenya

This article describes the Mara River in Africa. For the river in northern Canada, see Mara River (Nunavut).

The Mara River is a river of Africa, flowing in Kenya and Tanzania. It gave its name to the Masaai Mara reserve in Kenya. It lies across the annual migration path of the ungulates in the Masai Mara reserve.

The Mara River basin covers a surface of 13.504 km2, of which approximately 65 % is located in Kenya and 35% in Tanzania. From its sources in the Kenyan highlands, the river flows for about 395 km into the south-west direction. The basin can be roughly divided into four land use and/or administrative units:

The Mau Escarpment: The main sources of the Mara River, the Amala and Nyangores Rivers, drain from this escarpment. This part of the basin supports besides forests, both smallscale agriculture (less than 10 acres) and medium-size farms (often tea farms up to 40 acres).

The Kenyan Rangelands: In this area, the Amala and Nyangores rivers flow out of the Mau Escarpment and converge to form the Mara River. The River then meanders further through open savannah grasslands that is mostly governed by Maasai group ranches and used as pasture for livestock and for both small - and large-scale agriculture (more than 40 acres). The basins of four important tributaries to the Mara (the Talek, Engare, Sand and Engito rivers) are also located in this area, together with some upland areas like the Loita Hills.

The Protected areas: Eventually the river flows into the world-famous Maasai Mara National Reserve, where it merges with three of the four mentioned tributaries. On the Kenyan-Tanzanian border, the river flows into the Serengeti National Park and is joined by the fourth major tributary: the Sand (or Longaianiet) River. In these wildlife parks human activity is restricted to wildlife viewing.

Downstream Tanzania: Just after the Mara River flows out of Ikorongo Game reserve (which borders Serengeti National Park) it meanders sharply northwards. At the location where the river meanders into the southwestern direction again the main channel is lost in different streams, which feed the downstream Mara wetlands. These streams and wetlands continue for about 70 kilometers downstream. In this part of the basin human and livestock densities are high and small-scale subsistence agriculture is the main land use. The Mara River and wetlands flow out in Lake Victoria

The altitudes in the basin range from 2,932 meter around the sources in the Mau Escarpment to 1,134 meter around Lake Victoria. The amount of precipitation varies according to these altitudes. The Mau Escarpment receives most rainfall with a mean annual rainfall between 1,000 and 1,750 millimeter. The transboundery middle savannah grasslands receive an average between 900 and 1,000 millimeter, and the Kenyan lower Loita hills and the area around Lake Victoria only about 700 and 850 millimeter rain per year. On top of this rainfall variability in space, the region is also know for its rainfall variability in time, which means that the different areas all receive variable amounts of rainfall over the year. The rainfall seasons are bi-modal, with the long rains starting in mid-March to June with a peak in April, while the short rains occur between September and December.

Crocodiles are common near the river, as are many species of birds.

The river is a vital source to grazing animals nearby. Although during the dry season it may often appear shallow, it may swell to up to twice its normal size after heavy rainfall. This can create rapids in the river, which may lead to shortage of food for predators who cannot cross the river to hunt.

These large peaks in the river flow are connected to changes in land use in the catchments area. Decreasing vegetation covers are causing a faster run-off of rainwater. Near the river mouth in Tanzania, the rapidly fluctuating water levels in Lake Victoria of the previous century have further added to discharge difficulties of the Mara River. Consequently, floods have become more common and large parts of the Tanzanian Mara wetlands have become more permanent instead of temporary wetlands.