The River Njoro watershed is located in the Rift Valley, Kenya at 0°30' South, 35°, 20' East (see map below). The river itself is approximately 50 km in length with an estimated 272 km2 contributing source area. Originating on the Eastern Mau Escarpment at approximately 3 000 masl, the River Njoro winds through forested and agricultural lands before serving several urban settlements and terminating at 1 759 masl in Lake Nakuru.

River Njoro watershed location within Kenya.

Climate in the Njoro region is characterized by a trimodal precipitation pattern with long rains occurring from April - May, short rains occurring from November - December, and an additional small peak occurring in August. Mean annual rainfall measured at Njoro from 1949 - 2001 is 939.3 mm. Average annual minimum and maximum temperatures for the area range are 9° and 24° C, respectively.

Vegetation cover in the watershed ranges from 0% in areas affected by anthropogenic practices such as urbanization and intensive livestock husbandry to in excess of 90% in upland indigenous forests that are difficult to reach due to extreme topographic relief on the eastern rift escarpment. The catchment's uplands can be characterized into three principle vegetation zones. Heavily grazed moorlands and large agricultural fields are found in the uppermost section and bordering a dense closed canopy indigenous montane forest mixed with bamboo. Continuing further downstream, tracts of intact and deforested plantations are present consisting of various Cupressus and Pinus species. Between Logomon and Egerton University (see map above), there are various sized tracts of agricultural and pasture lands. Crops grown in the region include legumes, maize, sorghum, pyrethrum, wheat, barley, tomatoes, cabbages, yams, and potatoes. This diverse vegetation found in the watershed serves a wide range of purposes including timber harvesting, medicine, human food, livestock fodder, building material, and fuel wood.

In 1971, at Ramsar, Iran, 130 nations came together and signed an intergovernmental treaty for wetlands conservation. This treaty is known as the "Ramsar Convention". There are now 144 parties. When countries join the Ramsar Convention, they agree to designate at least one wetland site for inclusion on the "Ramsar List" based on regional and international significance to ecology, zoology, limnology, botany, or hydrology.

In Kenya, there are four listed Ramsar sites, all of which are soda lakes within the Rift Valley: Lake Nakuru, Lake Naivasha, Lake Bogoria, and Lake Baringo. First established as a bird sanctuary in 1961, Lake Nakuru National Park is best known for its diverse bird populations and rafts of flamingos covering its shorelines. The park also supports threatened and endangered Black and White Rhino species. In 1990, Lake Nakuru was designated as Kenya's first Ramsar site.

Five streams flow into Lake Nakuru: Njoro, Nderit, Makalia, Lamudiac, and Ngosur. Of the five streams, the River Njoro provides 65% of the total stream inflow. Siltation and fertilizer pollution from agricultural runoff are recognized as a few of the threats to the Lake Nakuru environment. Landcover changes in watersheds draining into the park, such as the River Njoro watershed, are thought to be possible point sources for pollutants.