Previous PageTable Of ContentsNext Page

Kenya country paper
Wetland classification for agricultural development in Eastern and Southern Africa


Kenya has a growing population projected to increase to 34 million people by the turn of the century. Though the country is undergoing industrial transformation, agriculture remains the mainstay of the economy. The country has an area of about 587 900 km2 of which 576 000 km2 is land surface. 88% of the land surface is classified as arid and semi-arid lands (ASALs) and the remaining 12% forms the medium and high agricultural potential land. This classification is based mainly on the moisture index as indicated by average annual rainfall and evapotranspiration.

The Great Rift Valley running north/south influences and determines the drainage pattern so that from the flanks of the Rift Valley, water flows westwards to Lake Victoria and eastwards to the Indian Ocean. The Rift Valley itself forms an internal drainage system. In this case therefore, Kenya consists of five major basins: Lake Victoria, Rift Valley, Athi River, Tana River and Ewaso Ngiro basins (Figure 1). However, only two of these basins can be rated to have surplus water resources: Lake Victoria and Tana River. The other three basins have water deficits and often rely on inter-basin water transfers to meet their basic water needs.

Annual rainfall is usually directly influenced by relief and the monsoon winds. In this respect and except for the Lake Victoria Basin that experiences one long rainy season, from March to September, the rest of the rainfall follows a strong bimodal pattern with the long rains falling in March-May and short rains in October-December. The mean annual rainfall is estimated at 621 mm, while the amount of rainfall that contributes to the surface and groundwater resources is estimated to range from 250 mm to 750 mm in arid and semi-arid areas and from 1 000 mm to 1 690 mm in the coastal belt, the highlands and the Lake Victoria basin. However, the actual contribution is less due to evapotranspiration.

Availability of surface water in the country for socio-economic and ecological sustenance is primarily influenced by its quantitative distribution in space and time and by its quality. As earlier indicated, the distribution countrywide varies from basin to basin with surface run-off and groundwater recharge

S.P.M. Kiai 
Ministry of Land Reclamation, Regional and Water Development 
Ministry of Research, Technical Training and Technology 

The main drainage basins of Kenya (Source: National Water Master Plan, 1992)

rate being influenced by rainfall intensity, soil types, vegetation cover and presence or absence of wetlands.

Within the available inland water bodies are the saline Rift Valley lakes whose waters (except for Lake Naivasha) are not available for all uses, on account of the chemistry thereof. The groundwater in many areas of the country, and particularly in the northeastern and rift valley regions, is highly mineralized limiting its application for agricultural use. The remaining freshwater resources are limited in quantity and are prone to pollution from agricultural, human settlement, industrial and other land-based activities.

From the information above, it can be observed, that there is generally a water shortage situation in the country, in spite of the seemingly high water resource potential documented in the National Water Master Plan prepared in 1992. The looming shortage can be attributed to the uneven distribution of these resources in space and time, resulting in only 20% of the country being well-watered.

Climate and Soils

The climate of Kenya is generally equatorial and influenced by the movement of the inter-tropical convergence zone (ITCZ) and the country's position on the Indian Ocean seafront. This influence is again modified by the altitudinal differences, giving rise to varied climate regimes.

The soils fall under ten broad categories: weakly developed, shallow/juvenile, sodic/saline, alluvial, deep to very deep, sandy, poorly drained, moderately deep to deep, deep red/weathered/acidic and shallow to moderately deep (Table 1). The soils, particularly in the ASAL areas, are highly erodible. The erodibility is determined mainly by slope, land use, vegetation cover and shallowness.

Summary of the Broad Soil Groups in Kenya (Source: Kenya Soil Survey)

Soil Group

Area in hectares

Natural fertility status

FAO 1974 classification

Weakly developed

3 638 235    


Xerosols and Yermosols


6 697 809    

moderate to high

Lithosols, Regosols,Rankers and Rendzinas

Sodic and saline

13 489 985    


Solonetz, Solonchaks,and Solodic Planosols


1 936 582    



Deep to very deep

3 796 669    


Nitisols and Andosols


436 683    

very low


Poorly drained

5 604 302    


Versols, Gleysols other Planosols, Greyzems, Chernozems and Vertoluvic Phaezems

Moderately deep to deep

7 408 426    


Luvisols, Cambisols, Phaeozems and Chernozems

Deep red, strongly weathered acid

6 839 464    


Ferrasols, Acrisols and Ironstone soils

Shallow to moderately deep

7 688 796    


Shallow Cambisols, Luvisols and Phaeeozems

Agro-ecological zones

Based on the factors discussed above: climatic conditions (mean annual rainfall and its distribution) and soils, Kenya has seven agro-ecological zones (Figure 2 and Table 2). Agro-ecological zone I (Alpine) is the high altitude mountainous zone that is least habitable and definitely not available for agriculture. Agro-ecological zones II to IV are the well-watered humid and semi-humid zones that support arable agriculture and hence a high population density. Zones V to VII comprise the fragile ASALs of Kenya where rainfall is generally poor, evapotranspiration is high and soils are shallow. These areas, however, support much of Kenya's wildlife, they host Kenya's terrestrial National Parks and are the principle livestock producing zones.

The ASALs have soils that are generally shallow and poorly endowed with organic matter. The soils are susceptible to both erosion and compaction.They have poor water holding capacity and are subject

Agro-ecological zones in Kenya


Areas of ASAL agro-ecological zones (AEZ) (Source: Farm management handbook of Kenya, Volumes I-IV, MOA, 1982)

Agro-ecological zone

% R/EO*

Area (km2)

% of country area

Zone IV, Semi-humid

40 - 50

27 000           


Zone V, Semi-arid

25 - 40

87 000           


Zone VI, Arid

15 - 20

126 000           


Zone VII, Very Arid

< 15

226 000           



466 000           


* Rainfall/Evapotranspiration ratios

to sodicity, alkalinity and salinization. The only exception are the riverine and the low-lying floodplains which have rich alluvial soils.

Kenya's wetlands

Wetlands are among the most productive ecosystems on earth. They allow interaction between water, soil, vegetation and light all the year round or during a greater part of the year. The depth of the water is such that it allows photosynthesis to occur, making wetlands productive life-supporting ecosystems. It is this association of water, light, soil and plants that typifies various wetlands of Kenya which are famous for their spectacular avifauna and fisheries resources.

Wetlands were the first ecosystem to receive international attention through the "Convention on Wetlands of International Importance especially as Habitats for Waterfowls", opened for signature at Ramsar, Iran, in February 1971. The convention defines wetlands as:

"Areas of marsh, fen peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt including areas of marine water, the depth of which at low tide does not exceed six metres. These areas may incorporate riparian and coastal zones adjacent to the wetlands, and islands or bodies of marine water deeper than six metres at low tide lying within the wetlands".

Kenya ratified this convention in 1990 and has since designated Lakes Nakuru and Naivasha as Wetlands of international importance (Ramsar Sites) in accordance with the requirements thereof.

The convention definition however, seems to cater only for sectoral interests of conservationists whose concern is water birds. In this respect therefore, Kenya has through the National Wetlands Standing Committee (NWSC) defined Kenyan wetlands as:

"areas of land that are permanently, seasonally or occasionally waterlogged with fresh, saline, brackish or marine waters at a depth not exceeding six metres, including both natural and man-made areas that support characteristic biota".

The above national definition has also an inclination towards biodiversity conservation but could allow exploitation of wetlands under the "wise use" principle.

According to the Kenya National Environment Action Plan (NEAP), prepared in 1994, a substantial proportion of Kenya's water resources is found in wetlands, which cover 2 to 3% of the country's surface area. These wetlands are diverse in type and distribution. Some of the larger wetlands of Kenya are shown in Figure 3 and they include the shallow lakes Nakuru, Naivasha, Magadi, Kanyaboli, Jipe, Chala, Elmentaita, Baringo, Ol'Bolossat, Amboseli and Kamnarok; the edges of Lake Victoria and Lorian, Saiwa, Yala, Shompole swamps; Lotikipi (Lotagipi) and Kano plains; Kisii valley bottoms and Tana Delta; and coastal wetlands including the mangroves swamps, sandy beaches, sea grassbeds and coral reefs. The list also includes various seasonal and temporary wetlands that occur where internal drainage allows water to collect in some seasons or in some years. These are found all over the country, including rock pools and springs in the southern part of Nairobi, west of Ngong Hills, and at Limuru. Man-made wetlands include the dams, primarily meant for hydropower and water supply, and wetlands created for purposes of wastewater treatment.This list is by no means exhaustive since inventory is still on-going.

Wetlands of Kenya

Significance of wetlands

The Kenyan wetlands play a fundamental ecological role and have potential as resources of great economic, cultural and scientific value. Among the critical values are:

Characterization and classification

Characterization and classification of wetlands has hitherto been sectoral. This has been carried out by various governmental agencies whose mandates touch on wetlands. Among the agencies is Kenya Wildlife Service (KWS) whose mandate includes management of protected wildlife areas, such as National Parks, Marine Parks, and Game Reserves. Other agencies are the Public Universities, National Museums of Kenya, the Forest Department, the Water Development Department, Regional Development Authorities, the Ministry of Agriculture, the Ministry of Planning and National Development and the Ministry of Environment and Natural Resources. Non-Governmental institutions involved include Kenya Wetlands Working Group (KWWG), Lake Victoria Wetlands Team, Lake Naivasha Riparian Owners Association (LNROA) and Kipsaina Wetlands Conservation Youth Group (KWCYG).

All these institutions have varying mandates and interests. Their classification is therefore varied and influenced by their different mandates. The emphasis of KWS, for instance, is conservation of wetlands for biodiversity conservation, while the focus of the Water Department is water catchment conservation for water development.

In spite of the different mandates, the institutions have generally classified wetlands on the basis of their origin and character as adopted by the Regional Wetlands Biodiversity Group at Mbale, Uganda in May 1996. This classification is shown in Table 3.

This classification was done with the technical assistance from the International Union for the Conservation of Nature (IUCN) and with the participation of institutions whose interests are basically biodiversity conservation. It is therefore necessary to develop criteria for wetland classification that

Wetland classification system for East Africa (Agreed by regional Wetland Biodiversity Group at Mbale, Uganda, in May 1996)







sea grass beds



coral reefs





rocky marine shores, reefs



mud flats, sand flats, salt flats



intertidal vegetated sediments: slat marshes, mangroves







estuaries and marine deltas





mud flats, sand flats, salt flats



estuarine marshes, salt marshes



estuarine swamps, mangrove swamps


Sodic and/or slaine water





sodic lakes, salt lakes




seasonally/occasionally inundated depressions, salt pans





sodic and salt marshes and swamps



springs, soaks and resultant pools







edges of perennial rivers, streams and waterfalls



inland deltas (including deltas in lakes)




seasonal/occasional rivers, streams and waterfalls



riverine floodplains, river flats, deltaic plains, riverine grass lands, mbugasd





freshwater lakes (> 10 ha) including shores subject to seasonal or irregular inundation (drawdown floodplains)



freshwater ponds, pools (< 10 ha)




seasonal lakes (> 10 ha)



seasonal ponds, pools (< 10 ha)





permanent swamps, marshes, dambose



seasonal/occasional swamps, marshes, dambos



peatlands, fens



montane wetlands (including bogs)



springs, soaks




shrub swamps, thicket wetlands



swamp forests


Man-made wetlands





fish ponds, prawn farms





farm ponds and dams



irrigated lands, rice paddy, channels, canals, dithces



seasonally flooded arable land


Salt production



salt evaporation pans





borrow pits, brick pits, mining pools, road impoundments, quarries



wastewater treatment facilities


Water storage



ponds, dams, reservoirs

a. refers to a lake

b. refers to a swamp or marsh

c. refers to river

d. refers to a seasonally inundated grassland

e. refers to a run-off area with an impervious sub-surface that accumulates water

may take on board all diverse shades of interests including agricultural, recreational, urban and industrial. Various attributes of wetlands should be considered in light of the national socio-economic development requirements and with full application of environmental safeguards including the principles enunciated in the UNCED's Rio Declaration: the Precautionary principle, the use of Environmental Impact Assessment (EIA) and the Wise Use principle called for by the Ramsar Convention.

Inventory and Mapping

As discussed earlier, wetlands in Kenya are diverse in type and distribution, but no coordinated national inventory has yet been carried out. Various sectors have been conducting inventory with a view to satisfying their sectoral needs. In this connection, significant capacity exists within the academia, the National Museums of Kenya and the KWWG to conduct transect walks for purposes of ecological studies.

KWS and various line ministries have the legal capacity to delineate a wetland principally for conservation. It is along these lines, that the Water Department within the Ministry of Land Reclamation, Regional and Water Development, along with the Forest Department, has been able to declare certain areas as water catchment areas limiting land based activities thereof.

Besides the legal capacity there exists technical and human capacity within the Ministry of Land and Settlement and the Ministry of Planning and National Development, to do land mapping, aerial photography and remote sensing. The Department of Survey is responsible for mapping while the Department of Resources Survey and Remote Sensing in the Ministry of Planning and National Development has GIS facilities and is responsible at national level for resource survey and documentation. This role is complimented at regional level by the various Local and Regional Development Authorities.

It is expected, therefore, that the National Wetlands Standing Committee will not only draw membership from the above institutions, but will also coordinate the inventory exercise along agreed characterization criteria, in order to come up with representative data and information on the type, status and location of the Kenyan wetlands.

Management of wetlands in Kenya

The management of wetlands is currently under various institutions, whose mandates and activities are not only sectoral but also uncoordinated and sometimes overlapping. Each of the institutions interacts with the wetlands in accordance with its interpretation of its mandate. Kenya Wildlife Service (KWS), for instance, being the national focal point for the Bonn Convention on Migratory Species and the Ramsar Convention on Wetlands, has the mandate of conserving Kenya's natural resources (including wetlands) within the gazetted protected areas, which are the national parks and game reserves.

The main objective of this conservation has been to enhance the ecological, economic, aesthetic and scientific values of the wildlife habitats and the biodiversity thereof for the economic benefits of Kenya and as a world heritage. Under this arrangement, several large wetlands have been accorded protection status. These protected wetlands include Lake Nakuru within the Lake Nakuru National Park, Lake Bogoria, Mzima Springs in Tsavo west National Park, Tana river Floodplain within the Tana river Primate National Reserve and Lake Amboseli within the Amboseli National Park. This management preference leaves out many other important wetlands unprotected and under threat of degradation.

The Ministry of Land Reclamation, Regional and Water Development, as the Ministry responsible for regional and water development, has a two fold concern for wetlands management. The Ministry recognizes:

Where irrigation is the principal land use activity upstream of a wetland, the ministry prefers that the wetland be left intact in order for it to receive the irrigation return water and filter out the nutrients, residual pesticides and the organic matter thereof and hence ameliorate the quality of the return water before the same can be discharged to the receiver. This has not been the case in the Kano plain because there are no wetlands, hence agricultural nutrients have found their way into the Winam Gulf of Lake Victoria causing a lot of eutrophication. Beside Kano plains, precautionary measures should be applied in the management of, among others,the wetlands around lake Jipe and the Tana delta.

Within the ASALs, most wetlands are traditional water sources and the only available grazing areas for the pastoral communities during drought. It would be advisable therefore to integrate the traditional management practices of the user communities in any proposed wetlands management programme.

Given these functions of a wetland, the Ministry of Land Reclamation, Regional and Water Development finds itself often at the cross-roads in the implementation of its regional development mandate particularly where the development may involve drainage of a wetland to create room for agricultural food production or alternative land use. An example of such a situation is manifested by attempts that have been made since the 1960s to drain the Yala swamp to increase agricultural land use. Wholesale draining of this wetland has not been possible because of the role it plays in the buffering of lake Victoria from the effects of Yala and Nzoia rivers. If drainage of this swamp will, as of necessity, have to go on, the ministry would prefer that EIA be carried out to determine and mitigate the impacts the activity will have on the hydrology and ecology of lakes Victoria, Kanyaboli and Sare river. Even with the determination of EIA, a portion of the wetland should still be left to be performing the buffering role and to support the biodiversity present in the swamp. Otherwise, it would not be in the interest of the ministry to have the swamp drained.

Other institutions that have been involved in the wetlands management in one way or the other include National Museums of Kenya, the Ministry of Environment and Natural Resources, the Ministry of Planning and National Development, the Ministry of Research, Technical Training and Technology, Universities, Local Authorities, Regional Development Authorities, the National Irrigation Board and NGOs. Among these NGOs is the Lake Naivasha Riparian Owners Association that has, in collaboration with the Government, prepared a management plan for the lake and its environs. While the management plan was a community initiative, the Government has participated in the formulation of the plan and in its implementation in order to ensure that the plan represents the interests of all stakeholders inter alia:

Realising the sectoral nature of the institutions mentioned above and the ever-increasing threat to wetlands, the Government of Kenya established in 1994 within the Interministerial Committee for Environment (IMCE) a National Wetlands Standing Committee (NWSC) with a mandate that includes the following:

Since its formation, the committee has carried out consultations amongst government and academic institutions, NGOs and community based institutions. This was done to build the necessary consensus on a clear national working definition of wetlands, and on elements to be included in the policy formulation. Consequently, the Committee has come up with the wetlands definition given earlier in this paper and has also drawn a framework within which the national wetlands policy will be formulated. The framework identifies the following as vital components for the policy:

Throughout the consultative process, various recommendations have been made to the Committee including:

Extraction of water for irrigation and drainage of wetlands for agriculture causes degradation and loss of biodiversity. Proper studies, including adequate consultations with local communities, should be carried out to determine the best option for each wetland. Where agriculture is the option, there is need to plan for proper management of all the likely environmental impacts.

The Government is committed to the development of irrigation in the country in spite of the various technical and socio-economic problems facing the existing irrigation schemes. These problems include salinity and sodicity, increase in water-borne diseases, soil compaction, reduction in water flow to downstream users, and change in watercourses. These problems result from lack of feasibility studies or inadequate implementation of the results of such studies.

Consequently, integrated planning should be done to ensure that irrigation and drainage for agriculture takes due consideration of the concerns of all water users: community participation; provision of infrastructure; treatment of water-borne diseases; control of water related vectors; water storage, discharge and recharge and all the other impacts of irrigation and drainage. It is also important to ensure that exploitation of wetlands for agricultural development does not cause such negative impacts on the functions and values of the wetlands to the extent of degrading them irreversibly. Every effort should be made to enhance multiple use of wetlands, including sustainable exploitation of the water and biodiversity contained therein.


From the above discussion, we wish to draw the following conclusions:


Government of Kenya. 1992. The study on the National Water Master Plan. Sectoral Report (N).

Government of Kenya. 1992. Development Policy for the Arid and Semi-Arid Lands (ASAL).

Government of Kenya. 1994. The Kenya National Environment Action Plan (NEAP).

Kiai, S.P.M. Environmental issues in the development of ASALs (unpublished).

Clarke, Robin. 1992. Water: International Crisis.

Crafter, S.A., Njuguna, S.G. and Howard, G.W. Proceedings of a seminar on wetlands of Kenya.

United Nations. 1992. Report of UNCED.

Previous PageTable Of ContentsNext Page