Basic Information on Lake Victoria South Catchment Area

Lake Victoria South Catchment (LVSCA) is in the southern part of Lake Victoria basin in Kenya. The catchment area is about 31,734 km2 out of which 4, 128 km2 is lake waters constituting about 13% of the catchment area.

The topography of the catchment area consists of low rolling hills separated by wide flat valleys that have been developed for intensive agriculture. The area has a gently sloping landscape and eroded surface in some places that expose rock outcrops like the Nyakach and Manga plateaus.

The catchment covers Kisumu, Homa-Bay, Kisii, Nyamira, Migori, Kericho, and Bomet Counties and parts of Siaya, Vihiga, Nandi, Nakuru, Narok, Uasin-Gishu, and Baringo Counties as seen below

 Drainage Network

The catchment comprises six drainage systems of Nyando, Sondu, Gucha-Migori, Northern and Southern Shoreline Streams and Mara which is a trans boundary resource shared between Kenya and Tanzania.

Table 3-1: Characteristics of Rivers in LVSCA

River Length


Drainage basin Area (km2) Mean monthly discharge (m3/s)
Nyando 120 3,652 0.66
Sondu 173 3,508 1.37
Gucha-Migori 149 6,600 1.83
Mara 181 8,705 1.18
Northern Shoreline Streams 27 1,985 0.12
Southern Shoreline Streams 65 3,156 0.19
 TOTAL 1265  31,734 


In LVSCA, the Gucha-Migori River, with a mean monthly discharge of 1.83m3 /s has the highest contribution of water to Lake Victoria, whereas Mara River has the largest drainage area.


Surface Water

The main rivers in LVSCA are:

  1. Nyando, Sondu, Gucha-Migori, Northern and Southern Shoreline Streams
  2. Mara River which is a trans boundary resource shared between Kenya and Tanzania.

Classification of Catchment Management Units

Following the delineation of the catchment area into CMUs, a Water Resources Classification System (WRCS) was introduced to capture the level of importance attributed to the resource in the management units with respect to three broad types of demands, namely; ecological, livelihood and commercial.

The classification system is mandated under Section 12 of the Water Act 2002 and is a measure of the relative importance attributed to the three competing types of uses: – Ecological (Environmental), Livelihood and Commercial. The class of the resource imposes certain conditions on the utilization of the resource with respect to the Reserve and the Resource Quality Objectives. The water resources classification is a set of guidelines and procedures that, when applied to a specific management unit, will ultimately assist in the process of maintaining a balance between protecting the water resources and using them to meet economic and social goals.

LVSC Management Sub-regions and Management Focus

Management Unit WRM Focus WRM Class Sub-regional Office
1 Northern Shoreline/Nyando Livelihood E3L1C2 Kisumu
2 Southern Shoreline/Gucha/Migori Livelihood E3L1C2 Kisii
3 Mara/Sondu Ecology E1L2C2 Kericho


LVSC management unit classification




Water Resources Monitoring

Water resources monitoring is carried out for surface water, ground water and water quality.

The surface water monitoring network in the catchment area has been rationalized and thirty eight (38) river gauging stations have been targeted for monitoring against twenty three (23) stations proposed in the National Water Master Plan 2030. The monitoring stations have been classified as follows:

  1. Five (5 No.) -National Stations;
  2. Thirteen (13 No.) -Management Unit stations;
  3. Nineteen (19 No.)- Inter-management Unit stations.
  4. One (1 No.) -Special Station

To facilitate the monitoring of groundwater resources, the catchment area has prioritised the following activities:

  • Development of dedicated monitoring boreholes;
  • Installation of airline/ piezometers and master meters;
  • Establishment of partnership with major groundwater users to collect data.

The region has identified fourteen (14) boreholes where water quality is monitored.