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Lake Naivasha: Experience and lessons learned

January 2005

January 2005

Authors:

Robert Becht

University of Twente

Average Monthly Rainfall Distribution for Lake Naivasha Region.

…

. Irrigated Farms.

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Figures - uploaded by Robert Becht

Content may be subject to copyright.

Content uploaded by Robert Becht

Content may be subject to copyright.

1. Introduction

Lake Naivasha (Figure 1) is a shallow basin lake, situated 80

km northwest of Nairobi in the Kenyan Rift Valley. The recent

developments around the lake constitute an interesting case

for natural resource management that is discussed in this

brief.

The lake contains freshwater supporting a rich ecosystem,

with hundreds of bird species, papyrus fringes ﬁ lled with

hippos, riparian grass lands where waterbuck, giraffe, zebra

and various antelopes graze, dense patches of riparian acacia

forest with buffaloes, bushbuck and other creatures, beautiful

swampy areas where waterfowl breed and feed and, at the

same time, magniﬁ cent views of the nearby volcanoes. Local

ﬁ shermen depend on the lake for ﬁ sh and crayﬁ sh. Although

the lake is situated in a semi-arid zone, after the rainy seasons,

the fragile soils of the surrounding hills and the valley bottom

produce grass where the pastoral Maasai bring their herds for

dry-weather grazing, thereby depending on the lake and its

various watering points.

Situated west of the main lake is Lake Sonachi, a small paradise

on its own. Sonachi (or Crater Lake as it also is known) is in

the caldera of a small volcano, with its own microclimate. A

dense forest covers the steep walls of the crater. High biomass

production has been recorded in this highly alkaline lake,

which often hosts ﬂ ocks of ﬂ amingos.

Lake Naivasha has no surface outlet, with the natural water

level changes over the last 100 years being more than 12

meters. The water level can change several meters within

just a few months, causing a shift of the shoreline of several

kilometers. These dynamics add an extra dimension to the

riparian ecosystem, as well as complicating the water resource

management issues.

In the colonial days, large cattle ranches occupied the bottom

of the Rift Valley. There was a large sisal plantation located

south of Lake Naivasha. The lake water was used only to

irrigate small acreages of fodder crops, provide water for

cattle, and grow vegetables. Large areas of papyrus were

cleared and converted into agricultural land. When the

water levels were receding between the 1930s and 1950s,

the Colonial Government was reluctant to approve water

abstraction permits.

In 1929, the Naivasha landowners organized themselves into

the Lake Naivasha Riparian Owners Association (LNROA).

The land below the arbitrary chosen lake level of 6,210 ft asl

(1,892.8 m asl) was put into the custody of the landowners in

1933, under the LNROA, although no permanent structures

were allowed to be built on this land. This proved to be a

wise move, since it has protected the riparian/shore line from

degradation. In the late 1950s, when the lake water levels

started to rise, after a couple of decades of falling levels, the

Administration began designing complex diversion schemes:

Water was to be transferred to Lake Elmenteita (also commonly

spelled Elementeita) to the north, and to Kedong valley to

the south. Fortunately, these plans never came to fruition.

Around 1990, the LNROA became more proactive and, in 1998,

Lake Naivasha

Experience and Lessons Learned Brief

Robert Becht*, International Institute of Geo-Information Science and Earth Observation (ITC), Enschede, the Netherlands,

becht@itc.nl

Eric O. Odada, Department of Geology, University of Nairobi, Nairobi, Kenya

Sarah Higgins, Lake Naivasha Riparian Association, Naivasha, Kenya

* Corresponding author

Figure 1. The Lake Naivasha Basin.

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278 Lake Naivasha

changed its name to the Lake Naivasha Riparian Association

(LNRA) and opened itself to a wider membership by instituting

associate membership. In 1999, the LNRA’s 70th anniversary,

the organization received the prestigious Ramsar Wetland

Conservation Award in the NGO category for its conservation

work on the lake.

The ﬁ rst large abstraction of the lake occurred when a

pipeline from the Naivasha basin to Gilgil and Nakuru Town

became operational in 1992. During the 1970s, there was little

irrigation, mainly fodder crops. In the early 1980s, however,

one vegetable grower decided to switch crops, successfully,

to the production of cut ﬂ owers. This decision has profoundly

changed the rules of the game.

The permeable and fertile soils, low rainfall, reliable supply

of good quality water, good climatic conditions, availability

of cheap labor, and easy access to Nairobi Airport, are the

ingredients of a booming ﬂ ower-dominated horticultural

industry around the shores of the lake. Since the ﬁ rst ﬂ ower

farms started in the early 1980s, there has been a fairly

constant increase in the area under ﬂ owers. In the late-1990s,

the ﬂ ower farms started to mushroom; this process is still

continuing, causing considerable concern regarding whether

or not the lake can sustain this increase.

The horticultural developments caused a shift in the

landownership and population around the lake. Before the

horticultural developments, the population was comprised

mainly of people born along the lake shores, or who

were attracted by its peace and beauty. Since the 1980s,

entrepreneurs have moved in, bought or rented land, and

started growing commercial ﬂ owers for export. Those who

had lived all or most of their lives in Naivasha, however,

realized that the paradise might be lost if the lake was

not properly managed. The LNRA became the vehicle that

started the lake management process in the late-1980s. The

energy, diplomacy and stamina of two LNRA members, the

Chairman and Honorary Secretary, have been instrumental

in starting and continuing this process. During this period, a

rather dormant stakeholder organization with a long colonial

history was transformed into an active organization interested

in sustainable development of the lake. The LNRA started

sensitizing their members and others on environmental issues,

compiled and summarized research that had been carried out

over the years into one document (Goldson 1993), encouraged

researchers to investigate the lake, started to develop a

management plan and sectoral codes of conduct, and started

to network and lobby in order to achieve their goals, with the

old riparian agreement becoming a powerful instrument for

protecting the government-owned riparian zone.

The large commercial growers felt that the direction the LNRA

had taken was not consistent with their commercial interests.

As a result, a small group of large ﬂ ower farms established the

Lake Naivasha Growers Group (LNGG). Conﬂ icts between LNRA

and LNGG arose and were subsequently reconciled, which

is all part of the consensus-building process and movement

toward a more institutionalized form of management, with the

result being that both groups are now working together for the

beneﬁ t of the lake and the economy.

The ﬁ rst important achievement in this process was the

designation of Lake Naivasha as a Ramsar site in 1995. As

a result, the Kenya Wildlife Services (KWS), custodian of

Kenyan Ramsar sites, became an important and inﬂ uential

partner with the LNRA. In 1996, the stakeholders agreed on

the Management Plan, with the Government of Kenya ofﬁ cially

approving it. This was the start of the implementation phase

of the Plan. The Lake Naivasha Management Implementation

Committee (LNMIC) was then formed, being the body to

execute the plan, drawing its members from various relevant

government and non-government stakeholder organizations.

The LNMIC has no executive powers, and no budget allocated

to it. It has to work through, and with, ofﬁ cial government

institutions with some limited support of wetlands-oriented

projects and NGOs. At the same time, the number of problems

to be addressed is manifold, with many important parameters

still unknown.

The population has increased tremendously around the lake,

resulting in a proliferation of unplanned settlements, which

lack basic amenities such as water, sanitation and waste

disposal programs. The lack of water in these settlements

forces residents to go to the lakeshore for domestic water,

laundry and livestock watering. As a result, the area is being

denuded of trees for ﬁ rewood and over-grazed by livestock,

thereby promoting erosion. There is a major issue of bush

meat and human/wildlife conﬂ ict, and wildlife is being snared

on a large scale for meat and skins.

The rapid developments resulted in many speculations on

the complex relationships between resources and resource

users, and subsequent disputes. Conservationists argued

that commercial farms are ruthlessly emptying the lake,

whereas commercial growers counter that the lake levels were

much lower in the 1950s, before agricultural activities began.

Although the lake is intimately linked to a very productive

aquifer, the inter-relationships are complex. Farmers pumping

groundwater claim that they do not exploit the lake. Many

unsubstantiated claims are made about the volume of water

abstractions, the effects of deforestation, the river sediments

accumulating in the lake, the effects of agrochemicals used

by the horticultural farms and smallholders in the upper

catchment, the unplanned urban and slum development, the

effects of cattle watering at the lakeshore, the relationships

between agrochemicals, overﬁ shing, introduced species and

biodiversity, the effects of untreated sewage discharged into

the lake, the effects of the geothermal plant just south of the

lake, and many more issues.

In 1996, the LNRA asked the Ministry of Water Development

to study the lake’s water balance and the water-related

environmental impacts. This study was carried out in

close collaboration with ITC-International Institute of Geo-

Experience and Lessons Learned Brief 279

Information Science and Earth Observation, in the Netherlands,

with the collaborative studies continuing to the present. The

Ministry has stationed a hydrologist in Naivasha to monitor the

water resources. Leicester University/Earthwatch have studied

the aquatic ecology of the lake since 1985. The lake also has

been the focus of research by many Kenyan scientists from

local and overseas universities, the Kenya Marine and Fisheries

Research Institute (KEMFRI), KWS and Kenya Agricultural

Research Institute (KARI).

The problems of disseminating the results of scientiﬁ c work

among laymen, and integrating scientiﬁ c knowledge in the

management process, are well known, not being unique to

Kenya. Nevertheless, the research on the water, environment,

socio-economy and ecology has helped resolve a number of

resource disputes and conﬂ icts, allowing the LNMIC to make

rational decisions.

The main issue however, regarding how a multimillion-dollar,

booming horticultural economy can exist within a Ramsar

site, became more quantiﬁ able. Over a long period, Kenyans

ruthlessly and unsustainably exploited their natural resources,

long-term planning was virtually absent, and law enforcement

was poor. Somewhere around the year 2000, however, the tide

changed, with an enabling environment for natural resources

management beginning to emerge.

The Environmental Management and Co-ordination Act

(1999) and the Water Act (2002) provided for the National

Environmental Management Authority (NEMA) and the Water

Management Authority (WMA). The ﬁ rst Authority is now

operational, whereas the latter is still in the process of being

established, and the concept of Integrated Water Resources

Management (IWRM) is being incorporated. The LNRA took a

more holistic approach, realizing that the RAMSAR site could

not be protected without addressing the problems in the

entire lake basin. It involved more and more stakeholders and

sectoral Codes of Conduct operationalized in the Management

Plan. The LNGG, who originally were mainly concerned about

access to water and land for horticultural production, also

began to appreciate that natural resources are ﬁ nite, and

that their over-exploitation would damage the entire ﬂ ower

industry. Furthermore, in their main European export market,

environmentally-friendly production is an asset. The LNGG

adjusted its earlier position and became a more active partner

in lake management, working together with LNRA on resource

issues, including land tenure, abstraction rates, agrochemical

control, and water availability. The LNGG employed a

horticultural expert, who actively promotes water conservation

and environmentally-friendly production techniques, and

the importance of water abstraction monitoring, among its

members. Many (large) farms have now voluntarily installed

water meters.

Several commercial growers realized that innovative techniques

and better irrigation management could reduce water usage.

They have started such activities as applying computerized

irrigation systems with soil moisture sensors, moving away

from overhead sprinklers to more efﬁ cient drip irrigation

systems, using coco-peat to improve soil characteristics,

using geothermal energy to increase CO2 and climate control

of greenhouses, storing roof runoff, and constructing artiﬁ cial

wetlands to treat wastewater.

The LNRA started to compile an inventory of its resources,

in close cooperation with ofﬁ cials of various Ministries. A

politically important achievement was a temporary ban on

ﬁ shing, which was enforced with the cooperation of the

commercial ﬁ shermen—a previously unheard of activity.

At present, the Ministry of Water Development and

Management is re-assessing abstraction permits, and water

pricing is being seriously discussed. Both LNRA and LNGG

have concluded that no new abstraction licenses should be

issued at present.

The Chairman of the LNRA wrote: “I believe that we were

also fortunate to have the ideal conditions of climate, soils

and water for ﬂ ower-growing. For all its potential to destroy

the lake, the industry is contributing greatly to sustainable

utilization of such a valuable resource. In absence of

the industry, I believe more abuse and more fragmented

development would have occurred and would have been more

difﬁ cult to contain” (Enniskillen 2002).

The management of Lake Naivasha is complex, and many

issues remain to be addressed and resolved. However, if the

management process begun some 10 years ago maintains

its present direction, Lake Naivasha may become a famous

example of Integrated Water Resources Management, one

illustrating that a proﬁ table economy and a Ramsar site can

co-exist.

2. Background

2.1 Biophysical features

2.1.1 General Setting

Lake Naivasha (0.45° S, 36.26° E), altitude 1,890 m asl, lies on

the ﬂ oor of Africa’s Eastern Rift Valley, covering approximately

140 km2. It is the second-largest freshwater lake in Kenya, and

one of a series of 23 major in the East Rift Valley—8 in central

Ethiopia, 8 in Kenya, and 7 in Tanzania—spanning latitudes

from approximately 7° N to 5° S. The overall climate of the

Eastern Rift Valley is semi-arid.

2.1.2 Geology, Soils, Groundwater

Only a few properties with direct relevance to managing Lake

Naivasha are discussed in this section.

The volcanic formations in the Rift Valley generally have a high

sodium (Na) content. The soils around the lake are developed

on volcanic ashes, mainly composed of ﬁ ne pumice grains, and

pumice layers are abundant. The interaction between volcanic

deposits and water in the lakes causes the genesis of zeolite

minerals.

280 Lake Naivasha

Due to their high pumice content, the soils around the lake are

very permeable, with a very low water-holding capacity. As a

result, irrigation water seeps quickly to depths below the plant

rooting zone. Very frequent (some farmers claim 10 times daily)

irrigation activity is necessary, with all excess irrigation water

seeping down to the groundwater. The soil properties are also

important in regard to deﬁ ning the path agrochemicals are

likely to follow; because of the high permeability and gentle

slopes, surface runoff rarely occurs and most agrochemicals

are transported toward the groundwater.

Groundwater plays an important role in the hydrology of

the Lake Naivasha system. The leakage from the lake is

part of the groundwater system, and exact identiﬁ cation

of this mechanism could provide for a better exploitation

of groundwater resources. Although groundwater is the

recipient of most agrochemicals used around the lake, the

water ﬂ ow is generally away from the lake. Thus, the chance

that agrochemicals will end up in the lake is low. The aquifers

around the lake have very high yields, and all irrigation north

of the lake is based on groundwater.

Because of the alkaline nature of the volcanic rocks, the soils

and groundwater have a high sodium content. This causes a

problem for growing high-quality crops, since the soil structure

is unsuitable. In general, groundwater in the area south of Lake

Naivasha is not very suitable for irrigation. Mixing groundwater

with surface water could prove a viable option. The abundance

of pumice is going to play an important role in the hydroponic

irrigation systems, since pumice is a perfect sub-stratum for

hydroponic culture.

The presence of zeolites also is recognized, but not well-

researched. Zeolites play an increasing important role in

organic farming and modern land management. They have

very high soil water retention capacities, and extremely high

Cation Exchange Capacities (CEC). They are able to capture

ammonia (NH4), an important fertilizer. Thus, more research on

the potential of zeolites in the ﬂ oricultural industry around the

lake is highly recommended.

2.1.3 Climate

The drainage basin lies within the range of the Intertropical

Convergence Zone (ITCZ). Mount Kenya and the Nyandarua

Range capture moisture from the monsoon winds, casting

a signiﬁ cant rain shadow over the Lake Naivasha basin. The

rainfall distribution has a bi-modal character, with long rains

during April-June and short rains during October-November

(Figure 2).

The long-term spatial rain distribution varies from about 600

mm at Naivasha Town to some 1,700 mm on the slopes of the

Nyandarua Mountains. The Kinangop Plateau experiences

an annual rainfall between 1,000-1,300 mm. The open water

evaporation of Lake Naivasha is approximately 1,720 mm/

year.

2.1.4 Hydrology and the Water Balance

The lake is fed by two perennial rivers, the Malewa and the

Gilgil Rivers, discharging 80% and 20%, respectively, of the

total inﬂ ow. The Karati River drains the area east of the lake,

being ephemeral and ﬂ owing approximately 2 months per

year. The area south of Lake Naivasha does not produce much

runoff reaching the lake. The drainage from the Mau Hills and

Eburu to the west inﬁ ltrates before it reaches the lake.

Both the Malewa and the Gilgil Rivers yield water of excellent

quality. The Electric Conductivity (EC), a proxy for Total

Dissolved Solids (TDS), may change very rapidly in a few

hours, although the mean EC for both rivers is around 100

µS/cm. Like all natural water in the area, the sodium content

is relatively high.

The lake ﬁ lls a shallow water basin with gentle slopes. Thus,

both the area and the water evaporation increase with rising

lake levels. The lake exhibits a dynamic behavior. Its water

level follows the long cycles of wetter and dryer periods with

the amplitude of about 12 m over the last 100 years.

The lake’s water level ﬂ uctuations have attracted the interest

of both scientists and water managers. In 1948, Mr. Tetley (an

Hydraulic Engineer in Nairobi) wrote: “The lake reached its

next highest peak in 1917 and since that year (1917) to April

1946 the level had a drop of about 37 feet; its area shrank from

say 86 square miles to less than 33 square miles and it lost

about ﬁ fteen sixteenth of the volume of water all in 29 years.”

Verschuren et al. (2000) studied the lake levels over the past

1000 years, identifying 4 periods when the lake almost went

dry, as well as periods with higher water levels than present.

Lake Naivasha actually consists of three lakes. The Crescent

Lake, the deepest part of the lake (18 m depth) can be

connected to the main lake, depending on lake levels. Oloiden

is a smaller lake at the south end of the Lake Naivasha and,

depending on lake levels, can be distinct from the main lake.

Figure 2. Average Monthly Rainfall Distribution for Lake

Naivasha Region.

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

100

120

140

160

180

Average Monthly Rainfall

Month

Experience and Lessons Learned Brief 281

The main lake is shallow (max. 8 m). Additionally, Crater Lake

or Sonachi is located near the southwestern part of Lake

Naivasha, but it is independent from the main lake.

Although the lake has no surface outlet, it still has good water

quality, with an EC value of approximately 300 µS/cm. It has

been recognized for a long time that only underground outﬂ ow

could explain the freshness of the lake water. The groundwater

levels, and the isotopic composition of groundwater, indicate

that this ﬂ ow is both to the north and the south. A small part

of the groundwater evaporates, and will escape in the form of

fumaroles in the geothermal areas. The remainder ﬂ ows into

Lake Magadi and Lake Elmenteita, taking thousands of years

for the water to arrive at these lakes.

The lake itself can be considered a groundwater outcrop of

a very good shallow aquifer that drains into a deeper aquifer

system, which carries the water towards the terminal lakes

(Magadi and Elmenteita). The groundwater system around the

lake is complex, with important management implications that

will be discussed later. The water generally ﬂ ows away from

the lake, with the exception of the western direction, where an

inﬂ ow from the Ndabi Plains enters.

The water balance of the lake has been calculated with a water

balance model (Mmbuie 1999). The water balance is calculated

for the period 1934-1983 (Table 1), therefore representing the

period before large-scale water abstractions began.

2.1.5 Biosphere

Little natural vegetation is left in the catchment. The

headwaters of the Malewa River, the lake’s main water source,

are situated in the Aberdare National Park and adjoining

gazetted forest. The vegetation consists of humid Afro-

mountain forest and bamboo. Fog frequently occurs, and may

play a role in the water balance. Although the Kinankop and

Bolosat Plateau were large grassland plains in the past, an

estimated 30% is now covered with maize or vegetables, and

many fast growing tree species. The upland areas are largely

covered by tree-savannah landscape and dryland forest, and

remnants of this forest can still be seen on the escarpment. In

the past, the bottom of the Rift Valley was an open savannah

landscape.

Lake Naivasha supports unique habitats, particularly

the fringing papyrus swamp and associated freshwater

biodiversity. As previously noted, the ecosystem comprises

three chemically distinct water bodies, the main freshwater

lake, a more alkaline and sometimes-connected lake

(Oloidien), and a crater lake (Sonachi).

The littoral zone is inhabited by macrophytes that provide

suitable habitats for ﬁ sh feeding and breeding, and mulch for

invertebrates. Although the species composition has changed

over time, the dominant ﬂ oating species are Cyperus papyrus,

Eichhornia crassipes (exotic), Pistia stratiotes, Salvinia

molesta (exotic), Wolfﬁ a arrhiza and Nymphaea (water lilies).

Submerged plants include Potamogeton schweinfurthii,

P. pectinatus, P. octandrus, Najas pectinata, N. caerulea,

Ultricularia reﬂ exa, and U. gibba. Although the areas of

submerged macrophytes vary considerably, the littoral zone

comprises about one third of the lake. This habitat exerts great

inﬂ uence on the lake’s biology and chemistry, and the plants

also are responsible for the richness of the bird population.

Water lilies almost disappeared in the 1980s, thought to be

caused by the introduced crayﬁ sh and accidentally-introduced

Coypus. The papyrus is considered the most important plant

of Lake Naivasha, occurring in the shallow water of the lake

edge, and on land where the sub-surface soil was saturated. It

almost completely surrounds the lake, forms ﬂ oating islands

in the lake and can be found up to 5 km up the Malewa River.

It acts as an efﬁ cient silt and nutrient ﬁ lter, and is capable of

recycling excess nutrients. It also forms an important habitat

for ﬁ sh (where submerged or ﬂ oating) and wildlife (e.g., birds,

hippos, buffalo) which use it as safe refuge and feeding area.

The quantity of papyrus in the lake has varied tremendously as

a consequence of ﬂ uctuating water levels, ﬁ res and, in some

cases, human encroachment.

One hundred and forty-three (143) phytoplankton taxa have

been recorded in the lake, including the species Microcystis,

Lyngbya, Oscillatoria and Melosira. The photosynthetic rate

is about 5 mg O2/m3/d in the open lake (50 mg Chl-a/m3).

Most productivity occurs in the top 3 m of the lake. The more

alkaline Oloidien and Sonachi lakes are more productive, with

Spirulina signiﬁ cantly present. The main zooplankton genera

are Cladocera, Copepoda and Rotifera. The zooplankton

biomass is positively correlated with the chlorophyll-a (algal)

concentrations, since zooplankton feed on the phytoplankton.

Twenty-eight taxa of invertebrates have been recorded,

associated with macrophyte beds.

The small-toothed carp (Aplocheilichthys antinorii) and

Barbus amphigramma were the only ﬁ sh species in the lake

before 1925 (the paucity of species probably due to historical

episodes of lake desiccation). The A. antinorii species had

disappeared by 1962, likely a direct result of the introduction

of the largemouth bass. The present ﬁ sh population

comprises introduced species, including largemouth bass

(Micropterus salmoides), introduced from the United States

in 1927, 1951 and 1956, Tilapia zillii (1956 from Lake Victoria:

the introduction also contained Oreochromis leucostictus,

now the most numerous ﬁ sh, ahead of bass), and other

tilapiine species not encountered today. Three cyprinodonts,

Gambusia, Poecilia and Lebistes, were introduced to control

mosquitoes. The exotic rainbow trout (Onchorhynchus mykiss)

occasionally strays into the lake from the Malewa River, while

Barbus amphigramma migrates between the lake and the river.

Table 1. Lake Naivasha Water Balance, 1934-1983

(106 m3/month).

Rain Surface

water inﬂ ow Evaporation Groundwater

outﬂ ow

95 220 260 55

282 Lake Naivasha

The Louisiana red swamp crayﬁ sh (Procambarus clarkii) was

introduced in 1970, as a food source for the bass.

The main food source for ﬁ sh fry is zooplankton (60%) and

chironomid larvae, followed by algae and detritus. Larger bass

feed on crayﬁ sh, ﬁ sh fry and frogs. Juvenile ﬁ sh exert predation

pressure on the zooplankton in the littoral zone, whereas the

zooplankton remain relatively untouched in the open waters.

The ﬁ sh are a source of food for numerous piscivorous birds

(e.g., ﬁ sh eagles, ospreys, cormorants, kingﬁ shers, herons,

pelicans), and also comprise an important ﬁ shery that is a

source of income and animal protein for the human population

around the lake and in nearby towns.

The Naivasha Thorn, or Yellow Fever Tree (Acacia xanthophloea)

is the dominant terrestrial tree species, forming the woodland

around the lake. It is an important habitat for birds and other

wildlife, and the undergrowth provides an important buffer

against erosion and helps prevent the transport of silt and

nutrients to the lake. Many animals are found on the shores

of the lake, in the acacia woodlands and the neighboring

national parks and sanctuaries, including hippopotamus (a

population of over 600), waterbuck, buffalo, giraffe, eland,

zebra, Thomson’s and Grant’s gazelles, bushbuck, duikers,

mongooses, otters, various snakes and rodents, and the

occasional leopard. The Malewa River delta comprises Acacia

woodland, before giving way to papyrus swamp.

Lake Naivasha regularly supports congregations of more than

20,000 water birds, with a mean of 22,000 (1991-1997). The

riparian, papyrus and littoral macrophyte zones provide safe

haven, foraging and breeding ground for many resident and

migrant bird species, and other wildlife such as the hippo,

waterbuck and buffalo. The woodland within the ecosystem

provides habitat for the globally-threatened grey-crested

helmet-shrike (vulnerable). Another globally-threatened

bird found in this location is the Basra Reed Warbler (near-

threatened), a winter visitor and passage migrant whose

exact status is unknown. There also are regionally-threatened

species, both as regular visitors and residents (e.g. great

crested grebe (critical), Maccoa duck (endangered), African

darter, great egret, saddle-billed stork, white-backed duck,

Baillon’s crake and African skimmer (all vulnerable)). The

riparian/papyrus habitat supports certain endemic species,

such as papyrus gonolek and white-winged swamp-warbler.

The large mammals, especially the hippos, may play an

important role in phosphorus recycling around the lake.

2.2 Political and Socio-economic Feature on

Development and Conservation

The Lake Naivasha basin covers two districts, Nyandarua

and Nakuru. Activities of many Government Ministries are

decentralized to the district level, thereby complicating an

integrated catchment approach. Development plans are

written for districts (District Development Plans), but these

districts cross-cut basin boundaries.

The lake has had Ramsar Convention status since 1995, with

most land within the Ramsar site being privately owned. The

land below the riparian boundary is government land, given in

custody to the riparian landowners. No permanent structures

are allowed.

The Lake Naivasha drainage basin largely occupies traditional

pastures of the pastoral Maasai. However, the basin became

part of the so-called white highlands after colonialization,

areas where only European settlers were allowed to own land.

The higher parts were mainly used for wheat and cattle, the

bottom of the Rift Valley for cattle, and around Lake Naivasha

sisal, Lucerne and vegetables were grown. After independence,

mainly members of the Kikuyu tribe occupied the parts suitable

for rain-fed agriculture. Because the land tenure in the bottom

of the Rift Valley remained largely unchanged, much of the land

around the lake is still owned by Kenyans of European origin.

The ﬁ shermen community is mainly Luo.

There has been irrigated Lucerne north of the lake, used as

fodder for dairy cows since the 1940s. The area between

Lake Naivasha and Lake Nakuru (80 km to the northwest) is

mainly used as cattle and game rangeland. Open rangelands

are south of the lake, where the Maasai graze their livestock

during the dry seasons. Closer to the lake edge are many

irrigated ﬂ oriculture ventures. The areas to the west and east

of the lake, which receive higher rainfall, are occupied mainly

by smallholders growing maize, vegetables and pyrethrum.

There also are some larger grain farms.

As a result of introduced ﬁ sh species, a ﬁ shing industry

has sprung up, with black bass, tilapia and crayﬁ sh being

commercially exploited. Recently, as a result of excessive

ﬁ shing pressure, the ﬁ sh stock became so depleted that a

year-long ban had to be imposed to redress the situation

and an annual closed season is now in force during the ﬁ sh

breeding season.

Lake Naivasha is a tourist destination, although not a major

one. There are two small national parks (Hells Gate and

Longonot) in the vicinity of the lake and nearby Aberdare

National Park. The area’s beauty, the extent of the bird and

wildlife, its proximity to Nairobi, and the many hotels, home-

stays and campsites at all budgetary levels, attract many

visitors, both local and overseas. About 40,000 tourists visited

the lake and its surroundings in 1998.

The KenGen Ol Karia geothermal power plant, situated 7 km

south of the lake, became operational in 1982, producing 45 KW

of power. An independent power producer started production

in an adjacent area in 2002, producing 12 KW of power, and a

second KenGen generation station was commissioned in 2004,

producing 575 KW of power.

The ﬁ rst ﬂ ower farm started in the early-1980s and, over a

period of twenty years, the ﬂ ori- and horticultural area has

increased from close to zero to some 4,000 ha. Growers

now produce at least 25 varieties of ﬂ owers (roses, spray

Experience and Lessons Learned Brief 283

carnations, gypsophila, alstroemeria, eustoma, etc.) and

vegetables (peas, baby corn, beans) for the export market,

all of which are irrigated with lake, river or groundwater. The

economic return per cubic meter of water applied on a crop

varies tremendously, with the values in Table 2 based on an

analysis carried out in 2000 by ITC.

The industry employs some 25,000 people directly, with a

similar number also indirectly dependent, both as dependants

and service providers. Based on the 1999 census, the Central

Bureau of Statistics reported the population of the Naivasha

urban core as 32,000 and the whole of Naivasha Municipality as

115,000 persons. According to a demographic internet source

(www.library.uu.nl/wesp/populstat/Africa/kenyag.htm), the

population of the urban core had increased from 6,900 in 1969

to 11,500 in 1977 and 35,000 in 1989.

The changes in land use patterns, especially north of the lake,

are rather dynamic, and a differentiation between vegetables

and fodder production is not always possible.

A number of observed trends include the following: movement

of the ﬂ ower industry from outdoors to indoor; fodder

production replaced by vegetable production; irrigated land

being abandoned; and the total area under irrigation being

rather stable over the past 10 years. Table 3 and Figure 3 show

area and location of the different types of irrigated farms as

well as abandoned land.

The booming horticultural industry’s inﬂ uence on the local

economy has never been studied in detail. What is certain,

however, is that the ﬂ oricultural business has attracted many

people. Social tensions exist in relation to wages, social

security, trade union membership, sexual harassment and

health issues related to exposure to agrochemicals. Trade

organizations and trade unions play a prominent role in such

issues and naturally try to organize farm workers, whereas

farm owners/managers naturally prefer an obedient and quit

workforce. Most, if not all, farms pay more than the legal

minimum wage. The larger farms also provide housing, free

medical services, schools for children of farm workers and

social and sport facilities. Overall, the explosive development

around the lake is nevertheless associated with many conﬂ icts

and disputes.

Table 2. Economic Return per Cubic Meter of Water Use.

Crop US$/m3

Flowers (indoors) 1.58

Flowers (outdoors) 1.25

Grass 0.04

Fodder 0.18

Macadamia nuts 4.86

Vegetables 0.72

Table 3. Irrigated Farms.

Crop Area (ha)

Abandoned 814

Flowers (indoors) 1,191

Flowers (outdoors) 704

Grass and fodder 128

Macadamia nuts 63

Vegetables 937

Vegetables and fodder 943

Total Irrigated Area 3,966

284 Lake Naivasha

Figure 3. Irrigated Crops around Lake Naivasha.

Abandoned

Flower (indoors)

Flower (outdoors)

Grass and fodder

Macadamia nuts

Vegetables

Vegetables and fodder

Experience and Lessons Learned Brief 285

3. Biophysical Environment

3.1 Water Balance

In the late 1990s, ITC was engaged to develop a simple,

spreadsheet-based water balance model of the lake and

its basin. The model used data from a variety of sources—

government and private sector—for a period from 1932 to the

present day. If a groundwater outﬂ ow of 4.6 million m3 per

month was allowed for, then the model was able to reproduce

the observed lake level from 1932 to 1982 with remarkable

accuracy (Figure 4). Over this period, 95 percent of all observed

monthly lake levels differed from the modeled levels by 0.52 m

or less. This accuracy makes the growing discrepancy between

the observed and the modeled lake levels after 1982 all the

more striking. By 1997, the observed level was 3-4 m below

that predicted by the model.

The onset of this decline in water level coincided with the

commencement of horticulture in the area in 1982, and there

was a close match between the annual water deﬁ cit by 1997

(60 x 106 m3) and the estimated water use based on the area

of horticulture and the crops grown. If the 1940s climatic

conditions recur, then the lake surface area will be reduced to

30 km2, compared to the present 120 km2.

In addition to the spreadsheet model, a groundwater-modeling

program (ModFlow) of the U.S. Geological Survey was also

used. Although the predictions from ModFlow were not better

than for the spreadsheet model, it allowed for studying the

effects of groundwater abstractions on the lake levels. It also

can be linked to groundwater quality models, in order to study

the transport of pollutants around the lake.

Overall, groundwater plays a more important role than

realized by the stakeholders and management, because it:

controls the irrigation efﬁ ciency; contains as much water as

the lake; transports pollutants; affects the lake levels; feeds

the geothermal system; and causes the lake to be fresh.

How much of the groundwater outﬂ ow ﬂ ows towards the

north (Elmenteita) and how much southwards, has been long

debated. A water balance study covering the southern Rift

Valley, from Lake Magadi to Lake Nakuru, indicated that some

15 million m3 ﬂ ows toward the north.

The water outﬂ ow from Lake Naivasha toward the south causes

over-irrigation to be a net loss with pollutants moving away

from the lake. In the north, where groundwater recirculates due

to groundwater exploitation, the excess irrigation will recharge

the aquifer, and also bring pollutants to the groundwater.

Overall, the large groundwater reservoir causes inertia of the

system, necessitating long planning horizons.

3.2 Water Quality, Aquatic Ecology, Sediment Load

Several authors have previously reported on the lake’s water

quality. The oldest (though not complete) analysis dates back

to the 1920s. The natural water quality is inﬂ uenced mainly

by solute inputs and lake level variations. The Total Dissolved

Solids (TDS) increase in times of receding lake levels, and

decrease after ﬂ oods. Irrigation from the lake decrease the

TDS concentration, whereas irrigation from the rivers increases

TDS concentrations. No disturbing trends, however, have been

detected so far.

Total phosphorus (T-P) is one of the elements controlling the

lake’s tropic status, and the following data (Table 4) have been

collected from Abiya (1996) and Kitaka (2000).

Figure 4. Long-term Water Level Change in Lake Naivasha.

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2EVHUYHG/DNH/HYHO

/DNH/HYHOVP

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Table 4. Total Phosphorus Concentrations in Lake

Naivasha.

Date T-P (ppm) Source

01 Jun 1984 89 Abiya

01 Jun 1988 73 Abiya

01 Jun 1990 10 Kitaka

01 Jul 1997 110 Kitaka

01 Sep 1997 150 Kitaka

01 Nov 1997 70 Kitaka

01 Mar 1998 50 Kitaka

01 Jun 1998 40 Kitaka

286 Lake Naivasha

The high values of 1997 are explained by that year’s high

runoff. Although Kitaka (2000) took a series of samples over

several months in 1990 (with a mean T-P concentration of 10

µg/L), the source of Abiya’s data is unknown. Time series data

on nitrate (NO3) and ammonia (NH4) are not available.

A data set collected by ITC in 2001 shows a considerable

temporal and spatial variation in the soluble phosphorus (PO4)

and nitrogen data. The two surveys, both with over 100 points

well spread over the whole lake, were done only one week

apart (Table 5).

The concentrations of chlorophyll-a increased from around 30

µg/L in 1982, to 110 µg/L in 1988, reaching 178 µg/L in 1995

(Unpublished LNRA Internal Report). McLean (2001) used 8

chlorophyll-a values obtained from Hubble in 1998 (cited in

McLean 2001), with values ranging between 0.01-0.08 µg/L.

The large difference likely can be attributed to the reporting

units (i.e., factor of 1,000 between µg/L and mg/l). Harper et al.

(1990) reported an increase from 20 µg/L in 1982, to 130 µg/L

in 1987. The N/P ratio is 2.1 (McLean 2001), suggesting that

nitrogen is the algal biomass limiting nutrient.

The large horticultural farms, and the many smallholders

in the upper catchment, clearly have an effect on the lake’s

water quality. Nevertheless, the trophic status of the lake

is still acceptable. Kitaka et al. (2002) classiﬁ ed the lake as

eutrophic (1998-99), becoming hypertropic after the El Niño

ﬂ oods (1997-98), and stated that the lake’s tropic status can

be explained solely on the basis of the Malewa River nutrient

input. A mathematical model, simulating agrochemical runoff,

also showed that the major nutrient input originates in the

upper Malewa River (Berrihun 2004).

Water transparency (Secchi depth) varies with site, ranging

between 5-150 cm. It is lowest in the north swamp area,

where suspended sediment is brought in by the rivers. Low

transparency also can be caused by algal growth, and algal

blooms have been observed, albeit infrequently.

Very few analyses are available on the pesticide levels in

the lake. Gitahi et al. (2002) reported that organochlorines

could be detected in black bass and crayﬁ sh, although no

organophosphates were detected in the same samples. The

total load to the lake has been calculated on the basis of farm

data.

Everard and Harper (2003) have shown that the reduction in

the lake’s papyrus fringe has been dramatic (Figure 5). Also,

the ﬁ sh catch has varied substantially over the last 40 years,

with relevant data compiled by Hickley et al. (2002) and LNRA,

as shown in Figure 6.

An issue of major concern is whether or not an “ecological

switch point” exists. This phenomenon is meant to denote

where an ecosystem (irreversibly) switches from one stable

state to another. Aquatic ecologists speculate that this point

for Lake Naivasha was passed a long time ago, when alien

species where introduced in the lake. The introduction of

the Louisiana crayﬁ sh especially has changed the original

submerged macrophyte-dominated ecosystem into a rather

poor macrophyte ecosystem. Smart et al. (2002) concluded

that P. clarkii (crayﬁ sh) could well have caused the observed

elimination of native plant species in Lake Naivasha. The

cyclical nature of populations of submerged plant species

and of P. clarkii in inverse proportion to each other suggest

the hypothesis that P. clarkii is a “keystone” species in the

lake ecosystem. Under the present lake stresses, however, the

occurrence of the next switch point is unlikely.

Table 5. Temporal and Spatial Variations in the Soluble-P

(PO4) and Nitrogen Data.

Nutrients

First Survey Second Survey

Mean

concentration

(ppm)

Mean

concentration

(ppm)

PO4 0.31 0.54

NO3 0.74 1.00

NH4 1.81 0.73

Figure 5. Lake Area under Papyrus.

1960 1970 1980 1990 2000

Area (km2)

Yea r

Figure 6. Total Fish Catch.

1960 1965 1970 1975 1980 1985 1990 1995 2000

200

400

600

800

1000

1200

Total fish catch (tons)

Yea r

Experience and Lessons Learned Brief 287

A new threat may emerge from the accidental introduction of

common carp to the lake in 2001. Britton (2002) concluded

that further work is necessary on the ﬁ sh population, to

monitor whether or not C. carpio successfully reproduces

and becomes established in the lake. If this does happen,

monitoring of the fauna and ﬂ ora of the entire lake will need

to be continued, since the species can be very destructive in

its foraging activities among the lake benthos. Because of

its native impacts on water turbidity and macrophyte growth,

C. carpio is considered a pest species in many countries,

including Australia and South Africa, and there are eradication

programs designed to completely remove it from aquatic

ecosystems.

Many stakeholders consider siltation of the lake to be a large

threat. The existing three sources of sediment to the lake

include: the Malewa and Gilgil River catchments (the upper

catchment); dust deposition from the atmosphere); and direct

transport through ephemeral streams surrounding the lake,

and from the riparian zone into the lake. The land use changes

have certainly increased the sediment load from the upper

catchment. Nevertheless, assessments by ITC in 1998 indicate

no serious erosion hazards exist.

Rupasingha (2002) processed the 1927, 1957 and 2001

bathymetric data and sediment samples from the Malewa and

Gilgil Rivers. Based on accurate bathymetric surveys, a total

input of 7 billion kg, equivalent to a layer with an average

thickness of 0.21 m (0.5 cm/year), has been calculated.

Analysis of the sediment data for the Malewa River explains

35% of the input. Thus, the remainder is from the Gilgil, from

the shore and small channels, and from the atmosphere.

Verschuren et al. (2000), who studied sediment cores of the

lake for paleoclimatic research, calculated a sedimentation

rate of 1 cm/year over the last 40 years. Adams et al. (2002)

concluded that the papyrus fringe is an effective sediment trap

for riparian sheet erosion.

A three-week experiment by ITC on atmospheric deposition,

using a series of water-ﬁ lled plastic basins distributed around

the lake, suggested the atmospheric input may be considerable

(up to 20%). The primary nutrient associated with sediment

transport is phosphorus, with Kitaka (2000) concluding that

the main phosphorus input is from the upper catchment.

4. Management Environment

4.1 Lake Management Program and Processes

To understand the management environment of Lake Naivasha,

it is necessary to discuss the many formal stakeholder and

informal stakeholder groups, and their mandates, objectives

and interrelationships, as well as the many more obvious and

less visible conﬂ icts, disputes and disagreements.

4.1.1 Stakeholders

Lake Naivasha Riparian Association (LNRA). The Lake Naivasha

Riparian Owners Association (LNROA) was founded in 1929 by

the riparian owners, with several descendants of the founding

members still living around the lake. The LNROA signed the

Foreshore Rights of Riparian Owners with Government in 1932,

giving the owners the right to use the exposed land below

the boundary, always provided that the ordinary occupation

in these premises shall be deemed to mean only the right

of access to water, the right of grazing, and the right of

cultivation. This boundary still plays a very important role even

over 70 years later. Persons buying or owning land around

the lake automatically became Association members. The

Association was not particularly active until 1986, when a new

and dynamic Chairman was elected. The members then started

to realize that the newly booming ﬂ oricultural developments

had the ability to jeopardize the future of Lake Naivasha.

The LNRA started a process of lobbying, awareness building,

networking and data collection to counter the degradation of

the lake by the ongoing activities. A report was commissioned

in 1993 by the LNRA, summarizing the knowledge on the

lake (Goldson 1993). In those days the “Foreshore Rights”

was the only legal document protecting the immediate lake

surroundings. In 1993, the LNRA started the process of

drawing up a Management Plan for the lake, which would

have the support of all sectors, and which was based on

voluntarily-adopted sectoral codes of practice under an

overall management strategy. The Management Plan was

adopted by the membership in 1996, subsequently by the

District Development Committee in Nakuru, and thereafter

by the Government as the ofﬁ cial Management Plan for Lake

Naivasha.

As a result of initiatives by the LNRA, the Kenya Government

(GoK) nominated Lake Naivasha as its second Ramsar site

in 1995, although it only comprised the area within the road

around the lake. The GoK reafﬁ rmed the LNRA’s Management

Plan as being the Government’s ofﬁ cial Management Plan

for its Ramsar site. The Kenyan Wildlife Service (KWS) is

the custodian, on behalf of the Government, of wetlands

in general, and Ramsar sites in particular. Accordingly, this

process received its full backing and support. The Management

Plan is to be implemented by the Lake Naivasha Management

Implementation Committee (LNMIC) (see below), under Terms

of Reference established and agreed with KWS. The Committee

consists of local and national organizations, including one

international group (IUCN). The LNRA, having initiated the

management process and playing a central role throughout,

remains a key member. The LNMIC membership is intended

to be representative of stakeholders’ interests, consistent with

administrative and decision-making efﬁ ciency, while at the

same time being a ﬁ rmly locally-based initiative.

The LNROA changed its name in 1998 to LNRA (deleting

the word “Owners”), becoming more open to stakeholders

other than the original landowners by allowing associate

membership. It is still, however, primarily an association

of individuals or companies which hold land title or legal

responsibilities in the area. The LNRA celebrated its 70th

anniversary in 1999, and received the prestigious Ramsar

288 Lake Naivasha

Wetland Conservation Award, presented at the 7th Ramsar

Conference of Parties in Costa Rica. The LNRA presently has

some 140 individual and corporate members. If employees,

other workers, and dependants are included, the LNRA can

be considered to represent at least some of the interests of

perhaps 100,000 people. Because the membership fee is

kept low (to allow more persons to become members), the

organization is continuously short of funds. It receives some

support from conservation-oriented NGOs, and employs one

full-time person with an background in aquatic ecology, as

well as having one Peace Corps volunteer. Small projects are

executed if the funding allows.

Lake Naivasha Growers Group (LNGG). The LNGG was founded

10 years ago by a small group of large commercial ﬂ ower

growers, thereby possessing considerable inﬂ uence and

unofﬁ cial power. The membership fee is based on the number of

employees, and with about 25,000 persons employed by LNGG

members, generates a steady income ﬂ ow. The LNGG began

as a response to the LNRA’s conservation ambitions, but has

since changed its stance. The large farms are now concerned

that they will be negatively affected over the long term by over-

exploitation of the lake’s resources. They also realize that their

European customers want “clean” or “eco-products” coming

from a protected environment. Labor and social conditions,

including working environment, health and safety factors, and

gender equity, also are increasingly of concern to European

customers. The Kenya Flower Council (KFC) has responded

to this concern with establishment of a Code of Practice. The

LNGG employs its Code of Conduct for its members, and also

is included as part of the lake’s Management Plan. A part-time

horticultural consultant has been employed to advise farms

on social and legal issues, conservation measures, better

pest control, and irrigation management. The group carries

out audits among its members, to ensure they comply with

the Code of Conduct and the Lake Naivasha Management

Plan. Several larger farms have looked at ways to improve

their impacts on the environment, including using integrated

pest management to reduce pesticide use and constructed

wetlands to treat their wastewater.

Kenya Wildlife Service (KWS). As an owner of riparian land,

KWS has been a long-time LNRA member. It also is the ofﬁ cial

custodian of all Kenyan Ramsar sites, as well as manager of the

area’s National Parks.

Lake Naivasha Fishermen’s Co-operative Society. This society

represents the small-scale commercial ﬁ shermen on the lake,

working in conjunction with the Fisheries Department (also see

ﬁ shery discussion in Section 4.2).

The Government of Kenya and Local Administration. The

Government, via several ministries and local authorities,

has a legal and constitutional stake, as well as legitimate

interest, in Lake Naivasha. The Fisheries Department is

responsible for managing the ﬁ sh stock, with the Ministry

of Water Development & Management responsible for water

management issues. Local Authorities at the District and

Divisional level include the Naivasha Municipal Council, Nakuru

District Development Committee and District Environmental

Committee.

Power Generating Companies. KenGen is a parastatal power

company with operations just south of the Lake. OR Power

is a new private power provider. Lake water also is used to

recharge the geothermal ﬁ eld.

IUCN (World Conservation Union). The IUCN is a member of

LNMIC, but has no further activities in the area.

Lake Naivasha Management Implementation Committee

(LNMIC). The Lake Naivasha Management Implementation

Committee (LNMIC) has the mandate to implement lake

management efforts for KWS, but presently has no ofﬁ cial

status nor legal power, although the process of gazettement

under the Environmental Management & Coordination

Act (EMCA) is well advanced. The membership comprises

nominated representatives of various organizations and LNMIC

subcommittees. The LNMIC has no formal budget.

Although the LNMIC has no direct jurisdiction, it can inﬂ uence

policy decisions and measures to a certain extent through its

members. The full members include:

• Lake Naivasha Riparian Association (LNRA);

• Kenya Wildlife Service (KWS);

• World Conservation Union (IUCN);

• Ministry of Water Development and Management

(MoWD&M);

• Ministry of Environment, Natural Resources and

Wildlife;

• Ministry of Livestock and Fisheries Development,

Fisheries Department;

• District Commissioner, Nakuru;

• Naivasha Municipal Council;

• Kenya Power Generating Company (KenGen);

• Ministry of Lands and Settlement;

• Ministry of Agriculture and Rural Development; and,

• Lake Naivasha Fishermen’s Co-operative Society.

Co-opted members of LNMIC include:

• Water Bailiff; and,

• The Chairmen of the sub-committees for Tourism, Eburru

Forest, Livestock, Biodiversity Monitoring, and Water.

In addition to the above-noted stakeholders represented in the

LNMIC, other members include:

• The large farms—Most large farms are members of both

LNRA and LNGG. As seen above, the interests of the two

organizations are not always compatible. Moreover,

some 5 large companies around the lake employ

thousands of people, exporting products worth millions

of dollars; as such, they can be seen to constitute a

stakeholder group on their own. As previously noted,

Experience and Lessons Learned Brief 289

several large farms also provide recreational, sports,

medical and educational facilities (schools, hospitals) to

their workers and families. The large farms also play an

important role in facilitating the introduction of water-

and environmentally-friendly technologies;

• The labor force employed by the large farms (and trade

unions which represent some of them)—With about

25,000 employees, this is the largest stakeholder in

terms of numbers of people. However, it proportionally

has the least effective inﬂ uence. No trade union,

for example, is present in the LNMIC. The working

conditions (salaries, exposure to pesticides, working

conditions, etc.), however, are regularly discussed in the

Kenyan press;

• Indigenous Biodiversity and Environmental

Conservation—A rather vague group, mainly concerned

with access to the lake;

• Upper catchment population—This group is highly

signiﬁ cant, given that it is indirectly responsible

for maintaining the inﬂ ow into the rivers, lake, and

aquifers. The soil, woodland, and land management

activities undertaken by the upper catchment dwellers

will eventually affect the system hydrology. They utilise

water for domestic water supply, livestock and farming,

with sediments and agrochemicals from the upper basin

ending up in the lake. This stakeholder group also is not

represented in the LNMIC, except by GoK ministries and

Local Authorities;

• Wood loggers—Legal and illegal logging activities affect

the drainage basin’s hydrological regime, increasing

erosion. Even though many activities are illegal, many

people nevertheless depend on forest products for their

livelihoods;

• The (Maasai) pastoralists—Living south and west of

the lake, the Maasai use the lake as a water point,

especially during drought periods. This group also is

not directly represented, and feels it does not beneﬁ t

much from the area’s developments. It also feels that its

health and environment are affected by gases escaping

from the geothermal power plants;

• Knowledge Institutes—Several universities and

institutions (e.g., Egerton University, Moi University,

Nairobi University, Kenya Marine and Fisheries Research

Institute, Leicester University/Earthwatch, and ITC)

regularly carry out research in the lake basin;

• Social & Environmental Certiﬁ cation Organizations—An

example is MPS;

• Kenya Flower Council (KFC)— Advising their members on

farm management, labor standards, and environmental

policies, the Kenya Flower Council (KFC) has established

a “silver standard”, covering workers’ pay, conditions,

and health, safety (to reach ILO conventions) and

some environmental conditions, whereby their “gold

standard” demands higher levels of environmental

performance. The Fresh Produce Exporters Association

of Kenya (FPEAK), focusing on vegetables and ﬂ owers,

utilises weaker guidelines;

• International customers for ﬂ owers and vegetables

(especially in Europe)— Increasingly purchasing not just

eco-products (e.g., organically-grown vegetables), these

customers also are concerned with “Fair Trade” issues,

such as wage rates, working conditions (especially

for women), child labor, health and safety for workers

regarding pesticides, housing and social standards, etc;

• Media inside and outside of Kenya—This group

especially includes environmental journalists;

• Agro-companies—Mainly companies concerned with

such agriciultural needs as seeds, agro-chemicals, etc;

• Tourist Industry—Although not a major stakeholder

in the area, there are two small National Parks in the

vicinity of the lake and the Aberdare National Park on

the eastern watershed, and a number of hotels, home-

stays and campsites; and,

• Internationally inﬂ uential environmental and civil

society organizations—These include the World Wildlife

Fund (WWF) and the above-noted World Conservation

Union (IUCN).

An important consideration, not always openly aired, is the

cultural and ethnic differences between stakeholders. A

large proportion of the commercial farms is operated and

owned by Europeans. The white people can be further divided

into descendants of originally-colonial landowners, and

more recent entrepreneurs attracted by the area’s business

opportunities. The large dairy enterprises and meat farms,

for example, are run by old UK-Kenya aristocracy and Italians.

By the end of the 19th century (the start of British colonial

times), the pastoral Maasai populated the area. However, the

major proportion of the population in the area is Kikuyu. The

ﬁ shermen are Luo people migrated from Lake Victoria.

4.1.2 Conﬂ icts

A summary of the most important conﬂ icts is presented below,

with a differentiation between technical conﬂ icts (facts based)

and institutional/social conﬂ icts (conﬂ icts of interest and

relational issues).

Technical conﬂ icts. These conﬂ icts are related mainly to

disputes over the interrelations between natural resources,

the allocation of these resources, and the humans exploiting

them. Many factual disagreements in the past have been

resolved by research ﬁ ndings, and the issues below can be

seen as priorities for further research and analyses.

Factual disagreements include the following:

• Disputes about the effects of water abstractions on lake

levels, and how much water can be safely abstracted;

• The size of the irrigated area, and the total water

abstraction occurring thereof;

• Lake pollution by agro-chemicals (claimed by some

environmental groups);

• Disagreements on the contribution of pollutants from

the upper catchment versus the large farms;

290 Lake Naivasha

• Extent of upper catchment water abstractions (thought

to be considerable by some lake water users);

• Reduced lake levels caused by abstractions that

decrease the catch, agro-chemicals reducing the catch,

and ﬁ sh (fry) being pumped out of the lake during water

abstraction (claimed by ﬁ shermen);

• Lack of deﬁ nition of sustainable water exploitation by

the involved parties;

• Growers using groundwater claiming they are not over-

exploiting the lake’s water resources;

• Uncertainties regarding who has legal abstraction

permits and who does not (it is speculated that many

users abstract more than allowed by their permits);

• The riparian land delimited by the riparian boundary

is government property, under the custody of riparian

landowners. No permanent structures are allowed

inside the boundary, although there is some dispute as

to what constitutes permanent structures. The boundary

is deﬁ ned by the 6,210 ft asl (1,892.8 m asl) lake level

contour, although some doubt exactly where this

boundary is located;

• Disputes over the relationship between the lake levels

and their dynamics;

• Disputes over the ecological functioning of the lake and

its surroundings; and,

• The effects of geothermal plants on the environment

(including lake levels, water quality and effect of emitted

gases on the environment and people).

Institutional and social conﬂ icts. These conﬂ icts are of a legal,

administrative, ﬁ nancial, social, or institutional order such as

relational issues including:

• Water users blame the Forest Department and (illegal)

wood loggers for mismanaging the forest reserves,

thereby diminishing water yields and increasing erosion,

and causing accelerated ﬁ lling of the lake;

• Existing game and cattle corridors have been closed by

agricultural land, and access to the lake generally has

been closed;

• The labor force claims it is exploited and underpaid;

• Whether or not the LNRA Management Plan really

considers the interests of all stakeholders, or is it more

the product of a group of environmentally-sensitized

white people (Wazungus)?

• Conﬂ icts between the media and stakeholders, with the

news on Lake Naivasha being more often negative than

positive; and,

• Some farms do not respect the ofﬁ cial riparian zone.

Conﬂ ict of interest. There also are conﬂ icts between different

socio-economic groups pursuing different goals, including:

• A major conﬂ ict exists between environmental groups

who want to protect the lake and its catchment from

over-exploitation, and commercial growers intending to

maximize their output;

• Nakuru Town wants more water for its urban water

supply, which could critically damage the lake;

• The tourist industry desires a natural landscape setting;

• The Maasai tribesmen claim historical traditional rights

to the area, including access to the lake to water their

cows;

• The large cattle farms claim that they have used the

local natural resources in an environmentally-friendly

manner, producing meat and milk for millions of

Kenyans, instead of destroying the environment like it is

claimed the ﬂ ower growers have done;

• Fishermen consider the large-scale horticultural

industry, using agro-chemicals, as a threat to their

livelihoods;

• Whether or not the ordinary Kenyan or the Kenyan state

generally beneﬁ ts from this economic boom, or is it only

a happy privileged few in the area; and,

• If water is priced, would the government or local

stakeholders, or both beneﬁ t from the revenues?

4.1.3 Programs and Processes

There has never been a government project or program directly

addressing the management of the lake. The LNRA and the

GoK have received small grants from various organizations for

this purpose, but the investments in the lake management are

limited at the present time.

The responsible government organizations lack funds, means,

and sometimes the interest, to seriously address the lake’s

problems. Until very recently, in fact, water and environmental

law was basically a copy of that established during colonial

days, and was unable to cope with modern land and water

management issues.

Although a water abstraction permit has always been required,

many users are either abstracting without a permit, or above

limits set by the permit. Two new laws have recently been

passed by Parliament, however, include the Environmental

Management and Co-ordination Act (1999) and the Water Act

(2002). The National Environmental Management Authority

(NEMA) and the Water Management Authority (WMA) have the

mandate to implement and enforce the new laws.

It was the combination of the many above-noted problems,

and lack of Government intervention (thereby creating a

management vacuum), combined with the visionary and strong

leadership of LNRA, that allowed it to emerge as a strong

stakeholder organization addressing the lake’s many pressing

issues. This 15-year process saw the evolution, from a small

group of LNRA members concerned with the future of the lake,

through a process of drafting the long-term vision, lobbying,

networking, solving disagreements among stakeholders,

consensus-building, awareness-raising, and reconciliation, to

the present form of lake management.

The milestones in this process included:

Experience and Lessons Learned Brief 291

• A report on the scientiﬁ c knowledge and outline of “the

way ahead” (1993);

• Preparation and ofﬁ cial adoption of the Management

Plan (1995) and, consequently, installation of the

LNMIC;

• Reconciliation between the LNRA and LNGG (around

1999);

• Co-hosting a scientiﬁ c conference on shallow tropical

lakes (1999);

• Declaration of the Lake Naivasha as a Ramsar site

(1995); and,

• Temporary ban on ﬁ shing, indicating that policies can be

enforced (2002).

The cornerstones of the lake’s present management are

the Management Plan and the implementing and executing

organization, the LNMIC.

Lake Naivasha Management Plan. The Management Plan was

written by a Steering Committee consisting of LNRA members,

and representatives of the Government and NGOs. It is a

dynamic document, already updated twice (carried out by the

LNMIC) since its inception, as knowledge of the lake increases

and the circumstances and laws change.

The primary objective of the Management Plan is to manage

existing human activities in the lake ecosystem through

voluntarily-adopted, sustainable, wise-use principles to

ensure the conservation of this freshwater resource and its

associated biodiversity. Secondary objectives include:

• Promoting and encouraging the major contribution

made to the national economy by the lake;

• Maintaining, conserving and, where necessary, restoring

the lake’s natural beauty and biodiversity;

• Achieving consensus via an understanding of, and

support for, the Management Plan through voluntarily-

adopted codes of practice and dialogue;

• Facilitating public access, tourism and research

activities, while also respecting private ownership of the

surrounding land; and,

• Immediately adopting practices on which there is

consensus, based on current knowledge; and adopting

other practices as the Plan is updated in the light of new

information from the monitoring program.

The Sectoral Codes of Conduct (CoCs) incorporated in the

Management Plan include LNGG, Power Producers (KenGen),

Lake Naivasha Tourist Group, Fisheries Industry, Livestock and

Dairy Industry, Wildlife, and Naivasha Municipal Council.

The Present Management Process. The LNMIC, responsible for

implementing the Management Plan, meets every six weeks on

average, and agreed action points are delegated to individual

members. The direct contact for day-to-day business, visitors,

enquiries, etc, is the active Honorary Secretary, while the

Chairman handles higher-level contacts.

Because the LNMIC has no executive power, it can only exert

its decisions through its members. The LNMIC can put pressure

on the members representing the Government to enforce laws,

or to take action, but the ﬁ nal authority remains with the

various government institutions. It can also motivate members

to adopt certain practices, although measurable targets are

not yet part of the process.

The ofﬁ cers of the key Government Departments (e.g.,

Fisheries, Forest, Water) are supported to execute their duties.

Subcommittees address the problems in special sectors, such

as Biodiversity, Water, and Horticulture (LNGG). Technical

information is provided by the subcommittees, Ministries,

LNGG, researchers or individual specialists. The LNRA, with

the support of LNGG, facilitates the LNMIC with a Geographic

Information System (GIS) with provision of a detailed

photographic coverage of the Ramsar site, riparian boundary,

and cadastral map linked to a database containing details of

the landowners.

The LNGG sub-commissioned a Hydrological Status Report,

which provides a fairly-complete overview of water related

issues, data availability, and advice on water resource

management issues and policies (Rural Focus 2002). A user-

friendly version of the Water Balance Model of the lake was

developed by ITC and is now in local ownership. A regular

newsletter also provides news, etc., to interested parties.

4.2 Reduction of Lake Stresses

The reduction of lake stresses is taken very seriously, being one

of the key duties of the LNMIC. Much credit goes to LNGG and

to some of the large farms. LNGG members consider that it is

very important that the proﬁ t level of the well-managed farms

is sufﬁ cient to make social and environmental investments.

Farms also are implementing or experimenting with new

technologies and management practices, including:

• Hydroponics—closed circulation systems, using the

locally available pumice as substratum;

• Use of coco-peat and compost to improve soil

characteristics;

• Biological pest control and biodegradable pesticides;

• Artiﬁ cial wetlands for natural wastewater treatment;

• Storage of roof runoff from greenhouses;

• Sophisticated irrigation systems, with soil tension

meters and the latest irrigation technology;

• Use of geothermal steam to heat greenhouses during

the night, to enhance plant growth using CO2 and H2S,

and for sterilizing crops and the growth medium without

the need for fumigation;

• Monitoring water abstractions;

• A shift from open-ﬁ eld crops to shaded growth or

greenhouses, thus reducing water evaporation losses;

• High temperature incineration of dangerous wastes;

• Plastic recycling;

292 Lake Naivasha

• Multiple use of crops, including baby corn for export and

the stems/leaves as fodder;

• Reducing the area under cultivation, while intensifying

output per area; and,

• Providing hospitals, schools, housing, social clubs for

the employees.

These large, innovative pioneer farms play an important

role in illustrating the possibilities and advantages of these

innovations to other farms. Technical innovation may serve

an economic and environmental purpose. The extra capital

investments needed for hydroponics are regained within a very

short period via higher productivity, no fumigation and lower

agrochemical inputs.

The LNMIC/LNRA and LNGG have also been engaged in the

following stress-reducing activities:

• Preservation of the riparian (shoreline) strips;

• Promoting use of safe, degradable pesticides;

• Controlling water uptakes;

• Minimizing fertilizer use;

• Preventing the introduction of alien species;

• Proper urban planning and development;

• Promoting sustainable tourism;

• Monitoring of resource status and development

activities;

• Forest conservation, erosion control, watershed

management; and,

• Environmental Impact Assessment and environmental

audits.

To r educe the sediment and agrochemical load to Lake

Naivasha, the LNRA has been sensitizing the inhabitants of

the upper catchment on good farming practices, although this

activity have been very low-key, due to inadequate funding.

Salvinia has existed in the lake since 1962; it became a major

ecological problem by the early-1970s, covering a large

portion of the lake. After chemical control failed, a biological

control agent (Cyrtobagus salviniae, a host-speciﬁ c insect),

was introduced to the lake and, by the early-1990s, had

effectively reduced the Salvinia cover to insigniﬁ cant levels.

Although water hyacinth was noted on the lake in 1988, the

lake conditions are not conducive to its rapid spread. Two

host-speciﬁ c biological control agents (Neochetina bruchii, N.

eichhornia) have been effective in containing the weed.

The Naivasha Municipal Council is in the process (with German

and Japanese assistance) of reducing the nutrient load to the

lake by upgrading the sewage network and plant.

KenGen is injecting condensed steam back into the geothermal

reservoir. These authors reject the (persistent) idea that the

geothermal exploitation has any effect on the lake levels.

The Ministry of Water Development & Management (a) has

carried out a detailed water abstraction point survey; (b) has

stationed an hydrologist and a Water Bailiff in Naivasha to

monitor resources and demand; (c) is training a water police

force to prosecute illegal water abstractors; (d) is actively

supporting hydrologic and environmental research; and (e)

has upgraded the monitoring network.

The issues related to overﬁ shing, and the consequent

regulation, has received much attention in the national press

and on the Internet. This issue provides an example that can

be assessed in more detail to show how management of Lake

Naivasha works in practice. As shown in Figure 6, the ﬁ sh catch

has been very low over the last couple of years. There is much

speculation over the high variation and overall decline of the

commercial catch. Many issues have been mentioned in the

resulting disputes, including variations in lake levels, declining

levels of riparian vegetation (papyrus and other macrophytes

and ﬂ oating vegetation), pollution (pesticides and fertilizers),

sediments changing the water transparency, ﬁ sh fry being

pumped out by water intakes, an incomplete foodweb,

overﬁ shing and the use of excessively-small gill-nets, and no

recovery time during spawning. Theoretically, the ﬁ sh catch

from the lake could be much higher, with various studies on

the theoretical ﬁ sh yield suggesting mean yields between 300-

1,200 tons/year (Hickley et al. 2002).

The two main ﬁ sh-related conﬂ icts involve:

• Fishermen versus the ﬂ ower farms—The ﬁ sh catch is

believed to be declining because irrigation lowers the

lake levels, and the farms pump out the fry and pollute

the lake; and,

• The environmentalist/LNRA versus the ﬁ shermen—Fish

stocks are declining due to overﬁ shing, poaching,

undersized gill-nets, and no recovery periods, as well as

no control/management of the quantity of ﬁ sh caught.

The main stakeholders in the ﬁ sh sector are the legal (and

illegal) ﬁ sherman, the Lake Naivasha Fishermen’s Co-operative

Society, Kenya Marine & Fisheries Research Institute (KMFRI,

with a research station in Naivasha), the Fisheries Department,

and LNRA.

The LNRA has considered the declining ﬁ sh catch as a sign of

environmental degradation, teaming up with KMFRI and the

Fisheries Department to reverse the trend. Since the catch

has become very low, the ﬁ shermen had little to lose, and

the licensed ﬁ shermen would certainly beneﬁ t from better

management and law-enforcement.

These conditions were ripe for implementation of a ﬁ shing

ban and during the year before an actual ban was imposed,

the Fisheries Department held regular meetings with the

legal ﬁ shermen, Kenya Marine & Fisheries Research Institute

(KMFRI), LNRA, ﬁ shmongers, a representative of the illegal

ﬁ shers, and the local authorities, and all aspects of the

ﬁ shing activities in the lake were discussed. The ﬁ shermen

were concerned that they were not catching sufﬁ cient ﬁ sh to

survive, and wanted the ofﬁ cial net size to be reduced (even

Experience and Lessons Learned Brief 293

though they admitted they were already using reduced net

sizes and still not catching sufﬁ cient ﬁ sh). KMFRI carried out

research which conﬁ rmed the lake was being overﬁ shed, and

that if something was not done to address this issue, the

ﬁ shing industry would collapse. The original rules laid down

for commercial ﬁ shing on the lake were based on research,

and concluded that only 30 boats should be permitted to ﬁ sh

the lake, and that the net size should be 4 inches and greater.

The number of boats, however, had increased to 130 over the

years, and, as noted above, the net size used had (illegally)

been reduced to 2 inches or less (some illegal ﬁ shermen were

even using shade netting).

After lengthy discussions, the ﬁ shermen concluded that their

only chance of sustaining their livelihood on the lake was to

cease ﬁ shing for some time, and so agreed the lake should be

closed to ﬁ shing initially for six months. However, when it was

clear that the ﬁ sh stock had not recovered sufﬁ ciently during

this initial period, another six months was added to the ban.

The ﬁ shermen accompanied and assisted the researchers,

thereby seeing for themselves how the ﬁ sh stock was

recovering during the ban period.

Because the Fisheries Department does not have sufﬁ cient

facilities to effectively patrol the whole lake, some of the

ﬁ shermen offered to help police the lake during the ban

period. There was also an initiative amongst the local

landowners, whereby they funded and facilitated a group of 15

ﬁ shermen (called the Task Force) to help police the lake. This

was reasonably effective in that, although the illegal ﬁ shers

were still quite active during this period, their activities were

considerably reduced.

The LNRA established a “liason ofﬁ ce” to ﬁ nd jobs for

ﬁ shermen on the ﬂ ower farms. The LNRA also provided a sum

of money to pay for the education of ﬁ shermen’s children so

that they would not suffer during the ban period. Not all of the

ﬁ shers took advantage of these initiatives, however, with many

moving back to Lake Victoria from whence they had originally

come. Just before the ban was lifted, the LNRA funded and

organized a workshop with the ﬁ shermen to ensure they were

fully aware of the rules.

When the ban was lifted it was decided, again in a public

meeting, that the number of ﬁ shing boats on the lake had to

be reduced, agreeing to a total of 43 boats. Although it was

a difﬁ cult task deciding who should have a license, it was

ultimately determined on the basis of how a ﬁ sherman had

behaved in the past; if he had stuck to the rules, he got a

license. The ﬁ shers also were warned that if they were caught

ﬂ outing the rules, they would be permanently banned from

ﬁ shing the lake. Several ﬁ shermen subsequently were caught

using small net sizes and were banned; their place has been

taken by other ﬁ shermen on the “waiting” list.

The practice of illegal ﬁ shing, using “seining” with very small

mesh nets, has not ceased, and is still damaging ﬁ sh breeding

activities, particularly since it takes place in the shallows,

which constitute the ﬁ sh breeding areas. This has affected

the recovery of the ﬁ sh stock and so, again after consultation

with the ﬁ shermen, it was decided there should be an annual

closed season of four months, to give the ﬁ sh a chance to

breed undisturbed. While the idea is good, it will not have

the desired effect if the illegal ﬁ shing cannot be stopped.

Although the ﬁ shermen have again been involved in trying

to stop these illegal activities, the illegal ﬁ shers have now

armed themselves, with a few nasty incidents occurring. The

ﬁ shermen have lobbied politicians and the media very well,

however, and many articles have addressed conﬂ icts in which

the poor ﬁ shermen were the victims of the powerful ﬂ ower

farms.

This is again an example whereby the availability of capital

helped resolve the conﬂ ict: the LNRA has assisted the Fisheries

Department to execute its duty (i.e., enforce the law), KMFRI

has been supported to monitor the stock, and ﬁ shermen have

been given alternative employment and school-fee grants. The

long-term ﬁ sh yield of the lake will certainly increase, which is

beneﬁ cial for the ﬁ sh-sector as a whole.

4.3 Environmental Status

Overall, Lake Naivasha is still in a relatively healthy state, and

the water quality parameters are in acceptable condition. The

spatial and temporal dynamics of the water quality parameters,

and the unknown details of historic data, however, make the

detection of trends difﬁ cult.

The main stresses on the lake are summarized as:

• Water abstraction;

• Agrochemical and sewage pollution;

• Destruction of riparian habitat (papyrus);

• Over–ﬁ shing; and,

• Erosion/siltation.

In regard to water abstractions, and pollution of the lake, there

is an ongoing discussion of the relative contribution of the

ﬂ oricultural industry versus the other water users in the basin

(see Section 3.1).

The recent introduction of sophisticated irrigation systems and

better irrigation management has deﬁ nitely led to a reduced

water use. This is partly offset, however, by an increase of the

area under irrigation for ﬂ owers and horticulture. The basin-

wide water abstractions have caused a reduction of the mean

lake level by approximately 2.5 m.

Due to the physical conditions surrounding Lake Naivasha,

the risk of agrochemicals ending up in the lake is limited. The

change to environmentally-friendlier pest control, and better

irrigation management, has deﬁ nitely had a positive effect on

the lake’s water quality. However, the agrochemical contribution

of the hinterlands to the lake is higher than the contribution

of the farms around the lake. To reduce the sediment and

pollution loads from the upper catchment, much work is

294 Lake Naivasha

necessary in educating farmers in watershed conservation

techniques and IPM (integrated pest management), although

very little work has been carried out so far.

The improper use of riparian land is being reduced.

Transgressors of the riparian boundary have been summoned

to stop their activities. In one part of the lake, papyrus burning

remains a problem. Overﬁ shing has recently become a major

concern. However, a ﬁ shing ban has already been issued twice

in the last 2 years and, therefore, the ﬁ sh stock is likely to

recover.

The siltation of the lake is resulting from 3 sources, including

sediment inﬂ ow through the main rivers, ﬂ ash ﬂ oods in the

semi-arid area around the lake, and atmospheric deposition.

In some areas south of the lake, wind erosion also is a serious

problem, due to overgrazing and improper land management,

with part of the wind-blown material being deposited in

the lake. Thus far, however, there is no evidence the lake is

seriously threatened by siltation.

4.4 Enabling Environment

4.4.1 The LNMIC and LNRA

The lake management institution (LNMIC) is operational, the

result of a 10-year process of lobbying, networking, awareness

and consensus building, as well as much energy of a few

individuals working hard without the assistance of an “ﬁ nanced

project”. The institution is likely to be sustainable, given that it

is strongly linked to an organization (LNRA) founded more than

70 years ago. However, the ﬁ nancial situation of both the LNRA

and LNMIC is poor, given that no structural support exists, and

the membership fees of the 140 members are not sufﬁ cient

to carry out the organization’s ambitions. The LNMIC is only

weakly supported by a team of professionals who advise on

developments and environmental threats by collecting and

analyzing data. As a result, management of the lake is rather

ad-hoc and not based on in-depth analysis of the system.

The main stakeholders seem to be ﬁ rmly embedded in both

the LNRA and LNMIC. Among the average Kenyan (Wananchi),

however, the organization still has still the image of a “white”,

elite club of conservationists and big businesses. The

inclusion of the main non-represented stakeholders (e.g.,

Maasai pastoralists, upper-catchment population, workers

and employees of the farms) would be necessary to introduce

these stakeholder needs and concerns, thereby changing this

image. The WWF will most likely soon begin a project in the

upper-catchment and, through the project, ensure that portion

of the population may get a voice in the process. The project

will focus on both Lakes Naivasha and Nakuru. The following

Naivasha-related activities are foreseen in the draft proposal:

• Water-awareness campaign;

• Halting illegal logging in the Aberdare Range and Mau

Escarpment;

• Economic development and improved land-use on the

Mau Escarpment and Aberdare Range;

• Rehabilitation and extension of the Nakuru and

Naivasha water supply systems (this module could be

split to cover Nakuru and Naivasha separately);

• Rehabilitation and enlargement of the sewerage system

at Nakuru Municipality, Naivasha Town and their

environs;

• Improving the solid waste disposal system in the Nakuru

Municipality, Naivasha Town and their environs;

• Collection, treatment and disposal of industrial and

agricultural chemicals, efﬂ uents and solid waste in

Nakuru and Naivasha; and,

• Controlling and improving sand mining along tributaries

of Lakes Nakuru and Naivasha.

Better relations with the press also could help change

perceptions. It is noteworthy that stories always address

the same issues in a negative way; namely, the ﬂ oricultural

industry emptying and poisoning the lake, causing low ﬁ sh

stocks and underpaying their labor force. Another negative

image of LNMIC is that the meetings are not public and the

records are conﬁ dential. The LNRA Newsletter only vaguely

covers the real management problems faced by the committee,

usually addressing less-important issues (e.g., a new bird

species has been seen; the arrival of a new staff member in

one of the Institutes). A positive activity would be to more

effectively communicate the management process, their goals,

success stories and failures to the general public.

4.4.2 The Management Plan

The main weakness of the Management Plan, and also the

new Water Act, is that they do not quantify sustainability, nor

deﬁ ne sustainable abstractions. The Management Plan does

stress the importance of an accurate water balance, and the

water balance model is sufﬁ ciently accurate for management

purposes. However, it cannot provide an accurate answer

to determining the sustainable abstraction of the lake.

There is no doubt that every abstraction from the basin will

result in a lowering of the mean water level in the lake. How

much drawdown is socially, economically and ecologically

acceptable, however, is an economic and political, rather than

hydrological, question.

4.4.3 Policy Context and Monitoring

The new Government of Kenya, in ofﬁ ce since the beginning

of 2003, appears to be taking water issues seriously. The new

laws on water and environment provide a good framework for

Integrated Water Resources Management (IWRM). The two

new institutions, the National Environmental Management

Authority (NEMA) and the soon-to-be Water Management

Authorities (WMAs) should have close links to the LNMIC,

something that is not yet the case. For many years, the

LNMIC has asked to be gazetted as a member of the Water

Apportionment Board, but so far without success.

Once the WMA is in place, it is likely that water users in the

Lake Naivasha will pay for their abstractions. These funds

could lift the lake’s management efforts to a higher level.

Because of cooperation between the government, LNRA/LNGG

Experience and Lessons Learned Brief 295

and research institutes, the lake is reasonably well monitored;

and the monitoring situation is certainly much better than in

other parts of Kenya. The monitoring system, however, is not

systematic and structural, and improvements are necessary.

The technical aspects of water resource management are

a costly affair. Collection of water data currently is carried

out by MoWD&M, universities and research institutes. The

formal Government policy regarding data is that the user pays.

Notwithstanding that data collection is expensive, selling it at

too high a price will result in the data not being used at all.

The ofﬁ cial price of the hydro-meteorological data set is about

$50,000, resulting in the data not being optimally used.

4.4.4 Research and Data for the Lake Basin

The quantity of data and research on Lake Naivasha and its

drainage basin is rather overwhelming. Lake levels have been

regularly monitored since 1909, and a few older observations

also exist. The rainfall for Naivasha Town is available since the

beginning of the 20th century. The area is well covered with

rainfall stations (35 of the total 65 stations are operational).

Other climatic variables (pan evaporation, radiation, wind

speed, temperature, etc.) also are available.

The discharge records of the Malewa River (main inﬂ ow) begin

at 1932. Several upper basin discharge stations also monitor

ﬂ ows. Hundreds of rain, surface, lake and groundwater samples

have been taken and analyzed for chemical, biochemical,

suspended sediments and isotopic composition. The oldest

lake water analyses date back to 1923. The bathymetry of

the lake was measured in 1923, 1958, 1983, 1991, 1997 and

2001. An aerial survey was carried out for the ﬁ rst time in

1948, and several times thereafter. A series of satellite images,

beginning in 1976, illustrates the land cover changes and land

use developments in the drainage basin. The geology has been

mapped out in detail for the geothermal projects, and some

80 deep wells (›1,000 m) have been drilled in the geothermal

areas. Many wells around the lake have been drilled, providing

information on the shallow hydrogeological conditions and

groundwater quality. Detailed inventories exist on water

abstraction points and water consumption, and researchers

have collected data on vegetation cover, biodiversity, aquatic

ecology and ﬁ sh stocks.

Early research was carried out primarily by the colonial

administration. From the 1960s on, however, the lake has

attracted a steady stream of researchers, producing hundreds

of articles, Master and PhD theses, reports and posters.

MoWD&M, KWS, KMFRI, KenGen, LNRA, and Kenyan and

foreign universities are actively involved in research on the

lake, and there is generally a good spirit of cooperation and

data sharing among these organizations. Research is being

sponsored mainly by Earthwatch, Shell, Kenyan Ministries and

Institutes, and local farms.

The total research investment over the last 10 years must

be on the order of $400,000, with part of this budget being

used for monitoring that should have been carried out by the

responsible Government institutions. The research has been

disseminated using various media, and theses are distributed

among main stakeholders, via articles in scientiﬁ c and popular

magazines, and lectures at workshops and in local stakeholder

communities. The research community has resolved a number

of key conﬂ icts and misconceptions, the most notable being

the water balance, the effects of irrigation on lake water

levels, the quantities of water being used by whom, the main

polluters, and the environmental status (health) of the lake.

The effective use of research in the management of Lake

Naivasha, however, is hampered by two factors. As previously

noted, the professional staff supporting the LNMIC in the

management process is missing. Further, most of the LNMIC

members do not have the time and background to fully

appreciate the relevant scientiﬁ c work or to use the results in

management decisions.

Universities often have different agendas than lake managers.

For a university, the research topic must be scientiﬁ cally

interesting, whereas the relevance of this criterion for lake

management is a secondary concern. In order to maintain

needed ﬁ nancial support, trade-offs often must be made,

and applied research seems to be more relevant for lake

management than fundamental research. Nevertheless,

research carried out by universities turns out to be very cost-

effective, compared to projects in which research is carried out

within the project itself.

One of the applied research questions of tremendous

signiﬁ cance that has not yet been solved is the lake’s discharge

mechanisms. If the seepage takes place in a concentrated

outﬂ ow zone, this water may be exploited. It may be concluded

that LNRA’s policy of stimulating research around the lake

has had important impact on resolving lake problems. Some

aspects of the systems behavior are obviously to complex to

easily translate in laymen’s terms. However, many other results

have assisted in resolving factual disagreements, the best

example being the effects of irrigation on lake water levels.

Whereas this constituted an emotional discussion in 1997, it is

no longer an issue. The effects are now known and accepted by

all stakeholders (see Section 3.1).

5. Lessons Learned and Recommended

Initiatives

One does not necessarily need a project to introduce the need

for effective lake management. A few committed individuals

may initiate the process and keep it going. Moreover, a

management vacuum amongst the different ofﬁ cially-

responsible authorities has created the opportunities for local

(management) initiatives in the case of Lake Naivasha.

The presence of a healthy economy in a regional context seems

to have inﬂ uenced the protection of the lake in a positive way.

The ﬁ nancial capital needed to introduce environmentally-

friendly water conservation measures is available. Due to the

large capital investments in horticulture, which are tied to the

296 Lake Naivasha

Kenyan economy, the private commercial sector has developed

a strong interest in sustainability. Technically-innovative

production techniques and systems are both economically and

environmentally interesting.

The two main lake stresses of water abstraction and

agrochemical pollutant loads are associated with two different

stakeholder groups. The irrigation water abstractions are

attributed almost exclusively to the ﬂ oricultural industry,

whereas the nutrient load (and likely also the pesticide load)

to the lake is attributed to the upper catchment population

practicing rain-fed agriculture. The Ramsar status/designation

also has helped enhance awareness on the need to conserve

natural resources.

In many other project-supported lake management programs,

large sums of money have been spent on data collection and

analysis. This activity can be carried out more cost-effectively

if lake managers team up with Ministries and knowledge

institutes. However, the dissemination of scientiﬁ c information,

and the use of such information in lake management, remains

problematic.

Although research can help solve many technical issues

concerned with data interpretation, as well as some of the

institutional conﬂ icts, the underlying conﬂ icts of interest

may still remain. Thus, community participation is a vital

element, particularly for a lake like Naivasha, where most

impacts emanate directly from competition over the use of

resources, and human settlements. In general, there is need to

entrench the policy on community involvement into resource

management.

Consensus building is essential in such community-driven

conservation programs, in order that all stakeholders can

move in the same direction. At the same time, consensus

building takes a long time, and often can signiﬁ cantly slow the

management processes needed to deal with urgent problems.

However, even if the need for community participation and

consensus building is acknowledged, enforcement of the new

national laws incorporating modern environmental and water

management concepts is an absolute requirement.

Funding remains a major challenge for community groups

interested in wetland/lake basin conservation. The fact

that there are many wealthy enterprises around the lake

that dependent on the sustainability of its resources may

negatively affect the willingness of donor agencies to ﬁ nance

lake management projects.

Having an accepted and ratiﬁ ed Management Plan, and

an Implementation Committee, is not sufﬁ cient to carry

out complex lake management. For example, the LNMIC is

composed of relatively senior representatives of various

stakeholders spending only limited time on their Committee

duties. The organizational layer below the Committee also

is absent. There is no operational team of professionals in

the ﬁ elds of water resources management, natural resources

management, regional planning, and aquatic ecology

working full time to collect and analyze data to support the

management process, set priorities and measure results—this

is an important omission.

Structural and strategic discussions on what is sustainability,

how the water should be allocated between different farms

and sectors, how to optimize economic output and at the same

time conserve the environment, how upstream-downstream

relations could involve the upper catchment population, or

what do if a series of serious drought years occurs, are issues

too complex and too political to be addressed by the LNMIC at

present.

Some speciﬁ c research-related lessons include:

• A willingness to cooperate, trust, and share data and

resources is more important than signing MoUs and

agreements;

• Pooling resources is cost-effective; and,

• Dissemination and communication of research results

to the stakeholders and decision-makers is difﬁ cult,

therefore ensuring that old myths concerning the lake

system are persistent.

Recommended initiatives. In spite of the ofﬁ cial nature of

the Management Plan, it is still necessary to institutionalize

the Plan and its Implementation Committee under the

Environmental Management and Co-ordination Act (1999). This

will enable the Implementation Committee decisions to carry

more weight for improved management effectiveness and, if

the principle of voluntarily-adopted practices fails, it will allow

them to enforce their decisions through the established legal

mechanisms. Thus, it is essential that the LNMIC becomes a

full member of the Water Apportionment Board.

One of the priority activities should be the introduction

of water charges, with the revenues being used for basin

management, rather than as extra income for the government.

The pricing mechanism should focus on lake management,

including minimizing environmental damage, while also

maximizing social and economic outputs and an equitable

distribution of resources. Issuance of new abstraction permits

should also consider the large differences in the economic

returns of different irrigated crops. Tradable water rights

may be considered as a future option. Introduction of water

pricing, however, also encompasses a danger. Control over the

revenues obtained from pricing may introduce power struggles

between the many organizations claiming a stake in the lake

management, thereby paralyzing the progress in integrated

lake management towards its sustainability goals.

Ideally, the whole process of data collection, updating

databases, analysis and interpretation, and the use of

simulation models and GIS, should be transferred from

research institutes to local ownership. A Lake Naivasha

Management Centre, where ofﬁ cials of different government

institutions and scientists work together and share equipment,

Experience and Lessons Learned Brief 297

data and knowledge to the beneﬁ t of the LNMIC and the Rift

Valley WMA, could be a new goal. The revenues of the water

charges could be used to establish and maintain such a

center, the establishment of which would mean a considerable

capacity building and education investment. This lake basin,

with its interesting conﬂ icts and good data, constitutes an

ideal training case for lake and IWRM management. Research

on the lake and its drainage basin should become more

embedded in the curricula of local universities, and research

by local and foreign institutes should become an integral and

ﬁ nanced part of lake management efforts.

Over the last 30 years the Government, and Kenyan and foreign

researchers have collected a tremendous quantity of data, a

large part being available at the LNRA’s Documentation Centre.

However, given the variety of topics and the large quantity

of material, it is impossible to overview or appreciate its full

content. The LNMIC could be assisted in this task if a Scientiﬁ c

Committee was attached to LNMIC to advise on relevant policy

matters. This committee could be composed of researchers

seriously studying the lake, as well as a few experts in lake and

wetlands management and/or IWRM.

The lake mangers should start the process of land planning. A

land zoning with designated land uses (agriculture, rangeland,

settlement, conservation) could be agreed upon and enforced,

via the issuing of water permits.

6. Summary

A unique set of conditions is found around Lake Naivasha,

including:

• A highly-proﬁ table and booming horti- and ﬂ oricultural

industry that depend on a protected lake/wetlands;

• A well-established and strong stakeholder organization,

an accepted Management Plan and an Implementation

Committee;

• An abundance of scientiﬁ c research on various aspects

of the ecosystem and the socio-economy;

• A generally environmentally-conscious stakeholder

community and enterprises that do not want to put

their future at stake by overexploiting the lake and its

resources;

• A positive change in attitude by the government

regarding management of natural resources;

• The large farms not being opposed to water charges, as

long the process is transparent and at least part of the

revenues are re-invested in the lake basin;

• Cooperation between LNRA/LNMIC, LNGG, Government

institutions and research institutes;

• The lake as a Ramsar site; and,

• Management of the lake and its basin receiving much

national and international interest.

All the necessary conditions are in place for Lake Naivasha to

become one of the ﬁ rst basins in Africa with a lake managed

for its sustainable use, in accordance with World Lake Vision

(World Lake Vision Committee 2003) and IWRM principles. The

present actors in the management process deserve support

in attempting to hurdle the last institutional, technical and

ﬁ nancial barriers to achieving this goal.

7. Acknowledgements

This report draws heavily on documents prepared by the

Lake Naivasha Riparian Association (LNRA), and there has

been close co-operation between the authors and LNRA in

designing and writing this document. However, the statements

and opinions expressed here are the main authors’ own, and

not necessarily those of the LNRA, University of Nairobi, nor

the ITC. Robert Becht did the majority of the writing is the

lead author; Eric Odada was contractually responsible for the

preparation of the brief.

The authors are indebted to many Kenyan partner institutions

that supported the “Lake Naivasha Hydrological and

Environmental Studies” of ITC over the past 7 years. Special

thanks for ﬁ nancial support goes to the Ministry of Water

Development and Management, Shell and the following

farms: Kijabe, Sher, Panda, Delamere, Oserian and Beautiline.

The efforts of over 60 ITC MSc students contributing to the

understanding of Lake Naivasha also are highly appreciated.

We also acknowledge the many valuable comments provided

by Mike McCall of ITC.

8. References

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Naivasha, Kenya.” Lakes and Reservoirs 2(3/4): 231-242.

Adams, C.S., R.R. Boar, D.S. Hubble, M. Gikungu, D.M. Harper,

P. Hickley and N. Tarras-Wahlberg. 2002. “The dynamics and

ecology of exotic tropical ﬂ oating plant mats: Lake Naivasha,

Kenya.” Hydrobiologia 488 (Developments in Hydrobiology

168): 115-122.

Berrihun, A.T. 2004. “Modelling water quality using soil

and water assessment tool (SWAT)” Master’s Thesis. ITC:

Enschede, the Netherlands.

Britton, R. 2002. “Investigations into the ﬁ sh population of

Lake Naivasha.” Earthwatch Project. (http://salmonriver.com/

sort/ﬁ shnaivasha.html).

Enniskillen. 2002. “The Lake Naivasha Management Plan:

Consensus building to conserve an international gem.”

Hydrobiologia 488 (Developments in Hydrobiology 168): ix-xii.

Everard, M. and D.M. Harper. 2002. “Towards the sustainability

of the Lake Naivasha Ramsar site and its catchment.”

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203.

Gitahi, S.M., D.M. Harper, S.M. Muchiri, M.P. Tole and R. N.

Ng’ang’a. 2002. “Organochlorine and organophosphorus

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organisms in Lake Naivasha (Kenya).” Hydrobiologia 488

(Developments in Hydrobiology 168): 123-128.

Goldson, J. 1993. A Three Phase Environmental Impact Study

of Recent Developments around Lake Naivasha. Lake Naivasha

Riparian Owners Association: Naivasha.

Harper, D.M., K.M. Mavuti and S.M. Muchiri. 1990. “Ecology

and management of Lake Naivasha, Kenya, in relation to

climatic change, alien species’ introductions, and agricultural

development.” Environmental Conservation 17: 328-335.

Hickley, P., R.G. Bailey, D.M. Harper, R. Kundu, S.M. Muchiri, R.

North and A. Taylor. .2002. “The status and future of the Lake

Naivasha ﬁ shery, Kenya.” Hydrobiologia 488 (Developments in

Hydrobiology 168): 181-190.

Kitaka, N. 2000. Phosphorus Supply to a Shallow Tropical Lake

and its Consequences: Lake Naivasha, Kenya. Ph.D. Thesis,

University of Leicester.

Kitaka, N., D.M. Harper and K.M. Mavuti. 2002. “Phosphorus

inputs to Lake Naivasha, Kenya, from its catchment and the

trophic state of the lake.” Hydrobiologia 488 (Developments in

Hydrobiology 168): 73-80.

McLean, P. 2001. Spatial analysis of water quality and

eutrophication controls in Lake Naivasha, Kenya. Master’s

Thesis. ITC: Enschede, the Netherlands.

Mmbui, S.G. 1999. Study of long term water balance of

Lake Naivasha, Kenya. Master’s Thesis. ITC: Enschede, the

Netherlands.

Rupasingha, R.A.P. 2002. Use of GIS and RS assessing lake

sedimentation processes. Master’s Thesis. ITC: Enschede, the

Netherlands.

Rural Focus. 2002. Hydrological Status Report. Lake Naivasha

Grower’s Group: Naivasha, Kenya.

Smart, A.C., D.M. Harper, A.C. Gouder de Beauregard, S.

Schmitz, S. Coley, F. Malaisse. 2003. “Feeding of the exotic

Louisiana red swamp crayﬁ sh, Procambarus clarkii (Crustacea,

Decapoda), in an African tropical lake: Lake Naivasha, Kenya.”

Hydrobiologia 488 (Developments in Hydrobiology 168): 129-

142.

Verschuren, D., K.R. Laird and B.F. Cumming. 2000. “Rainfall

and drought in equatorial East Africa during the past 1,100

years.” Nature 403: 410-414.

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ILEC: Kusatsu, Japan.

Disclaimer

The ﬁ ndings, interpretations and conclusions expressed

in this report are the views of the authors and do not

necessarily represent the views of The World Bank and its

Board of Directors, or the countries they represent, nor do

they necessarily represent the view of the organizations,

agencies or governments to which any of the authors are

associated. Also, the colors, boundaries, denominations, and

classiﬁ cations in this report do not imply, on the part of The

World Bank and its Board of Directors, or the countries they

represent, and the organizations, agencies or governments to

which any of the authors are associated, any judgment on the

legal or other status of any territory, or any endorsement or

acceptance of any boundary.

Hydroclimatic Analysis of Rising Water Levels in the Great Rift Valley Lakes of Kenya

Preprint

Full-text available

May 2021

Study RegionThe Great Rift Valley lakes of Kenya have recently experienced significant increases in their water levels, negatively impacting the local communities. This has provoked renewed concerns about the causations, with various geological, anthropogenic and hydro-climatic influences hypothesized as potential causes of the water level rises. Study FocusThis study analyses and documents water level fluctuations in Lakes Baringo, Bogoria, Nakuru, Solai, Elementaita and Naivasha. Hydrometeorological analyses are undertaken to understand potential causes and lake volume data is used to derive the “Integrated Catchment Response” (ICR), a magnitude which allows to relate changes in water balance components to signals observed in the lake volume changes.New Hydrological Insights for the RegionCompared to 1984-2009, the recent increases in lake areas range from 21% for Lake Naivasha to an extraordinary 123% for Lake Solai. Mean annual rainfall for 2010-2020 increased by up to 30%. Actual evapotranspiration also increased, but to lesser extent compared to rainfall. The results illustrate that changes in catchment properties due to anthropogenic influences or changes in underground permeability are not necessary to explain the lake level rises. Based on the ICR only surprisingly minor changes in the water balance are necessary to explain the lake level rises, since an increase of only 0.4 - 2% of mean annual effective rainfall leads to the observed phenomena.

DIVERSITY, DISTRIBUTION AND BIOMASS OF PHYTOPLANKTON IN LAKE NAIVASHA, KENYA, MSc.THESIS, KISII UNIVERSITY

Thesis

Full-text available

Dec 2019

Argwings Owino Omondi

Lake Naivasha is a shallow freshwater lake that supports a wide but uneven biodiversity of plants and animals but no native fish as most of the fish species in the lake were introduced. The lake’s ecosystem has been undergoing major changes due to anthropogenic and natural factors that influence its limnology. This study aimed to determine the diversity, distribution, and biomass of the phytoplankton community in this lake. For a period of 6 months from February 2019 to July 2019 covering dry and wet season, water samples from the lake were analyzed to determine the spatio-temporal trends of phytoplankton and associated environmental variables which included nutrients concentrations, temperature, conductivity, DO, pH and transparency. Monthly samplings were done and samples analyses using the standard procedures. Samples were collected in triplicates for the determination of nitrate nitrogen, soluble reactive phosphorous, total nitrogen, total phosphorous, ammonium nitrogen, silicates, and chlorophyll a. Water temperature, conductivity, DO, and pH were measured in situ using multimeter probe YSI model. The results showed the mean temperature of 22.73 ± 1.6 °C, DO 8.51 ± 0.87 mg/L, conductivity 233.85 ± 26.94 μS/cm, pH 8.13 ± 0.3. TN were 471 ± 170.61 µg/L, PO4-P 5.88 ± 2.12 µg/L, TP 97.97 ± 49.06 µg/L, NO3-N 6.70 ± 3.55 µg/L, NH4-N 18.93 ± 10.91 µg/L and SiO2 3.18 ± 2.99 mg/l and Chlorophyll a 21.51 ± 4.25 mg/m³. Total phosphorous, total nitrogen, silicates, temperature, pH, dissolve oxygen, conductivity, TDS and secchi depth showed significant seasonal differences. A total of one hundred and twenty four (124) species of phytoplankton belonging to six (6) taxonomic families were identified. Chlorophyceae was represented by 43 species consisting of 34.68 % by species composition, Bacillariophyceae was represented by 38 species consisting of 30.65 % by species composition. Cyanophyceae was represented by 24 species leading to 19.35 % species composition. Zygnematophyceae, Euglenophyceae, and Dinophyceae recorded the least species composition. Chlorophyceae recorded the highest total phytoplankton biovolume of 623.41 mm3/L, followed by Bacillariophyceae with 533.16 mm3/L and Cyanophyceae with 114.55 mm3/L. Dinophyceae recorded the least phytoplankton biovolume of 82.36 mm3/L. The total number of algal species was highest at Hippo point sampling site with 72 species, followed closely by 68 species in Crescent Island, then Oserian Bay sampling site with 66 species. Mouth of R. Malewa recorded 59 species, Sher Bay had 58 species, this was followed by Mid Lake station with 56 species, and Sewage Discharge Point had 55 species. Shannon-Wiener diversity (H’) index ranged from 2.0455 at the Mouth of R. Malewa to 2.7077 at Oserian Bay and was highest in July. Lake Naivasha showed a high phytoplankton diversity with significant physico-chemical parameters relationship. There is need for long-term and continuous ecological and hydrological monitoring especially on nutrients seasonal dynamics for proper understanding of seasonal effects of nutrients to algal biomass and diversity, which could be used as an indicator of eutrophication level in the lake.

Hydroclimatic analysis of rising water levels in the Great rift Valley Lakes of Kenya

Article

Full-text available

Jun 2021

Study Region The Great Rift Valley lakes of Kenya have recently experienced significant increases in their water levels, negatively impacting the local communities. This has provoked renewed concerns about the causations, with various geological, anthropogenic and hydro-climatic influences hypothesized as potential causes of the water level rises. Study Focus This study analyses and documents water level fluctuations in Lakes Baringo, Bogoria, Nakuru, Solai, Elementaita and Naivasha. Hydrometeorological analyses are undertaken to understand potential causes and lake volume data is used to derive the “Integrated Catchment Response” (ICR), a magnitude which allows to relate changes in water balance components to signals observed in the lake volume changes. New Hydrological Insights for the Region Compared to 1984−2009, the recent increases in lake areas range from 21 % for Lake Naivasha to an extraordinary 123 % for Lake Solai. Mean annual rainfall for 2010−2020 increased by up to 30 %. Actual evapotranspiration also increased, but to lesser extent compared to rainfall. The results illustrate that changes in catchment properties due to anthropogenic influences or changes in underground permeability are not necessary to explain the lake level rises. Based on the ICR only surprisingly minor changes in the water balance are necessary to explain the lake level rises, since an increase of only 0.4–2 % of mean annual effective rainfall leads to the observed phenomena.

EVALUATION OF SPATIAL AND TEMPORAL HYDROLOGICAL DROUGHT USING SURFACE WATER SUPPLY INDEX IN MALEWA RIVER CATCHMENT, NAIVASHA

Article

Full-text available

May 2022

There has been a critical problem of the devastating natural hazard (hydrological drought) which greatly affects a significant proportion of the large population particularly those living in arid and semi-arid areas. The flow regime of the Malewa River is reducing due to the river fluctuation, increasing scarcity of water during dry periods. The purpose of this research was to assess spatial and temporal hydrological drought using Surface Water Supply Index (SWSI) at Malewa River catchment. The data were based on hydro-meteorological data which included rainfall, level of water at Lake Naivasha, and streamflow of Malewa River for the years 1980-2018. They were obtained from Water Resources Authority (WRA) in Naivasha and Kenya Meteorological Department (KMD) in Nairobi, Kenya. The field data were first normalized to have all input attributes temporary variables with their distribution having zero means and a standard deviation of 1. Later the normalized data were calculated using basin-calibrated algorithm of SWSI to determine the hydrological condition. In SWSI, the highest percentage of classification for the stations were near the average of -0.9 to 1.0, with 34% for the Malewa area and 30% for the Turasha area. In spatial distribution analyses, hydrological drought severity was highest along the southern part of the catchment and lowest along with Eastern and North-Eastern areas. Therefore, hydrological drought severity was experienced in the catchment in terms of temporal and spatial analyses and increased along the flow path of the river. Hydrological drought assessment shows a technical manner for a comprehensive understanding of drought offering proper mitigation strategies and plan to control this natural disaster.

Pan Africa Science Journal Temporal Variation of Physical and Chemical Characteristics of Water in Selected Locations in Lake Naivasha, Kenya Volume 2 -Issue 2

Article

Full-text available

Jan 2022

Lake Naivasha is a freshwater lake whose water quality is of great concern because of human and natural influences that affect its water chemistry and limnological characteristics. The main objective of this paper was to determine the temporal variation of physical and chemical characteristics of water in Lake Naivasha. Physico-chemical parameters were studied monthly and collected in triplicates from seven pre-defined stations from February 2019 to July 2019. Samples were collected in triplicates to determine nitrate nitrogen, SRP, TN, TP, ammonium nitrogen, and silicates. Water temperature, conductivity, DO, secchi, and pH were measured in situ using a multimeter probe. The findings of the study showed that the mean temporal variations in TN were 471 µg/L ± 170.61 SD, TP 97.97 µg/L ± 49.06 SD, NO3-N 6.70 µg/L ± 3.55 SD, NH4-N 18.93 µg/L ± 10.91 SD and SiO2 3.18 mg/L ± 2.99 SD. The temporal in situ readings showed a mean temperature of 22.73 °C ± 1.6 SD, DO 8.51 mg/L ± 0.87 SD, and pH 8.13 ± 0.3 SD. Single-factor ANOVA test revealed that temperature, dissolved oxygen, conductivity, pH, TP, TN, and silicates were significantly different between the sampled months (p <.05). The results depict that anthropogenic activities, seasonal shifts, and variation play a key role in determing the lake's water quality and limnological characteristics. There is a need for monitoring the limnological characteristics of Lake Naivasha basin to understand the water quality dynamics of the ecosystem and to come up with relevant management strategies.

International Journal of Fisheries and Aquatic Studies 2020; 8(4): 217-222 Assessment of Spatio-temporal variation of selected Physico-chemical properties of Kapkatet Wetland, Kericho County, Kenya

Article

Full-text available

Aug 2022

Spatio-temporal variation in physico-chemical properties of Kapkatet Wetland was studied. Globally, anthropogenic activities have compromised the integrity of wetlands as far as their sustainability is concerned. Kapkatet wetland is of great importance to the local community and the natural environment. However, it is under threat from anthropogenic activities and climate change effects which has altered its structure and functionality. The study was conducted to investigate the impact of anthropogenic activities on selected water quality parameters and nutrients concentration. Physico-chemical parameters were measured in situ using a multimeter parameter probe (model no YS1 15B) at three sampling stations for a period of six months February to July 2019. Nutrient samples were collected in triplicates and analyzed using standard method described in APHA, 1998. Data was analyzed using ANOVA at p = 0.05 to investigate whether there were significant differences among sites and months. Tukey's pairwise comparison was done for any significant difference detected. The spatial results showed the mean DO to be 4.84 ± 0.97 mg/L, pH 5.7 ± 0.61, Temperature 21.26 ± 1.51 °C, NO3-N 41.6 ± 51.69 μg/L, SRP 364.98 ± 237.87 μg/L and NH4-N 33.47 ± 31.76 μg/L. Temporal results showed the mean DO to be 4.84 ± 1.07 mg/L, pH 5.7 ± 0.96, temperature 21.26 ± 1.03 °C, NO3-N 41.61 ± 38.19 μg/L, SRP 33.47 ± 10.43 μg/L and NH4-N 16.43 ± 6.75 μg/L. These findings confirm that the various anthropogenic activities within the wetland have negative impacts on the Kapkatet wetland water quality. In order to improve water quality in this wetland, proper management of wetland should be done as far as farming activities along the riparian zones, human encroachment and demarcation of the wetland is concerned.

Tectonic Control of Groundwater Recharge and Flow in Faulted Volcanic Aquifers

Article

Full-text available

Jul 2022
WATER RESOUR RES

Groundwater dynamics in continental rift zone settings remain poorly understood because of the spatial heterogeneity in flow, storage, and recharge dynamics. The Central Kenya Rift is an excellent example where, though groundwater is important for domestic, irrigation, and geothermal energy exploitation, its hydrogeological properties remain largely unknown. Existing conceptual groundwater models assume flow from the high‐elevation, humid rift flanks to the low‐elevation, semiarid rift floor, but the role of the faults that fracture the aquifers is commonly unaccounted for. We applied geochemical, isotopic (δ¹⁸O, δD, ⁸⁷Sr/⁸⁶Sr, ³H‐³He), multivariate statistical methods, and knowledge of geological structures to determine recharge sources, flow, and residence times to revise the conceptual flow model. Results show that groundwater is primarily recharged by meteoric waters, river input, and Lake recharge. The faults impart a control on the groundwater flow within four sub‐compartments. Major differences in flow patterns exist between the eastern and western rift flanks: surface and groundwater transfer from the eastern flanks to the rift floor occurs via relay ramp structures, and flow on the west side takes place laterally from the high escarpment. Although ³H‐³He dating shows that the age of groundwater ranges from a few to >>50 years, most of the groundwater in the rift‐floor area is free of ³H and was recharged before the 1960s. Hence, we propose that these areas receive episodic recharge and represent the most sensitive groundwater resources in the rift. To inform sustainable groundwater development, a robust monitoring network is required to capture the heterogeneous groundwater dynamics.

Shifts in composition of fish species of fishery in Lake Naivasha, Kenya: Trend implications for fishing effort, yields and revenue

Article

Mar 2022

Assessing fisheries resource composition and exploitation trends is vital for the sustainable management of fish stocks. Accordingly, the present study analysed datasets of fish catches and market values from 1991 to 2019, and from 2004 to 2019, respectively, to determine shifts and trends in fish species composition, fishing effort, fish yield and revenue. The annual percentage weight composition and relative biomass of different fish species in the lake were calculated over the study period. Fishery time series data comprised fishing effort, fish yield, catch per unit effort (CPUE), revenue and revenue per unit effort (RPUE). Moving average (MA) trends at 5‐year intervals were plotted and the Mann–Kendall (MK) method applied to detect trends at the 95% confidence limit. The results identified shifts in fish species composition during various periods, with Nile tilapia Oreochromis niloticus comprising 94% of the total weight of fish landed in 2019, with an overall mean relative biomass of 4221.4 ± 2229.7 kg/km2. The mean total fish catch (1683.5 ± 420 ton/year), CPUE (10.6 ± 2.0 ton/boat/year) and modal effort (176 boats) were highest from 2014 to 2019 period. The fishery revenue increased in 2019 (US$ 4,096,490) with a RPUE of US$ 22,263.5/boat/year. The fishing effort, fish yields, CPUE, revenue and RPUE trends increased significantly (p < .01), likely being related to the shifts in species composition. Lake Naivasha is a learning model for improving fisheries management and yields through stock enhancement interventions. Nevertheless, the increasing level of fishing effort warrants a precautionary approach to ensure sustainability of the fishery resource.

Assessment of Rainfall, Streamflow and Reservoir Level Trends for Malewa River Catchment, Naivasha, Kenya

Article

Full-text available

Jan 2021

Export horticulture and labour migration in Kenya: Translocality and transiency in a secondary town

Article

Jun 2021
GEOFORUM

Based on a study of globalized export horticulture at Lake Naivasha, Kenya, this paper explores urban development at the intersections of foreign capital investments and translocal labour mobility. We argue that patterns of translocality largely track the specific requirements and temporalities of the cut flower and vegetable industries, lending an ephemeral and provisional character to the town of Naivasha and the urban sprawl encompassing it. Drawing on empirical research in Naivasha and literature on urbanization in contexts of export agriculture, we contribute to scholarly debates on the transiency of urban spaces in the Global South by focusing on “secondary towns”, or those small- and medium-sized towns that rapidly emerge around foreign investment sites. Our findings suggest that urban transiency, understood as a provisional form of urbanism, is especially pronounced in such secondary towns compared to more consolidated urban areas.

Organochlorine and organophosphorus pesticide concentrations in water, sediment, and selected organisms in Lake Naivasha (Kenya)

Article

Full-text available

Nov 2002

Water, sediment, red swamp crayfish (Procambarus clarkii) and black bass (Micropterus salmoides) from Lake Naivasha were analyzed for selected organochlorine and organophosphorus pesticide residues. The mean p,p'-DDT, o,p'-DDT and p,p'-DDE residue levels recorded in black bass (28.3 ( 30.0), 34.2 (54.0) and 16.1 (16.1) g kg–1, respectively) and crayfish (4.6 (5.1), 3.2 (2.8), and 1.4 (1.1) g kg–1, respectively), were higher than previously recorded. This indicated recent usage of technical DDT in the lake's catchment. Levels of p,p'-DDT, higher than those of p,p'-DDE further emphasized this. Mean lindane, dieldrin, -endosulfan and aldrin concentrations in black bass were 100.5, 34.6, 21.6 and 16.7 g kg–1, respectively. The same residues were detected at lower concentrations in crayfish at 2.0, 2.0, 2.0 and 1.9 g kg–1, respectively. The higher fat content (3.7 2.7% SD) in black bass (compared to 0.6 0.3% in crayfish) accounted for the significantly higher residue concentrations in black bass. Organophosphate pesticides were the most commonly used pesticides in the lake's catchment, but none was detected in any of the samples. The results indicate that there is need for further work to identify sources and fate of pesticide contaminants, as well as to improve monitoring of pesticide use throughout the catchment.

The dynamics and ecology of exotic tropical species in floating plant mats: Lake Naivasha, Kenya

Article

Full-text available

Jan 2002

The floating water fern Salvinia molesta has occurred in Lake Naivasha since the early 1960s and during this period has obstructed fishing activities and navigation. In recent years the extent of Salvinia has declined markedly. Since 1988, a second floating weed, Eichhornia crassipes (water hyacinth), has colonised the lake. Salvinia formed large mats around the edges, bays and lagoons and had very few plant or invertebrate species associated with it. Mats of E. crassipes, however, support a greater abundance and variety of animal and plant species, which shows a relationship with mat size. This seems to have facilitated plant succession but without a zonation typical of the classic hydroseral sequence for the lake.

The Status and Future of the Lake Naivasha Fishery, Kenya

Article

Full-text available

Nov 2002

Lake Naivasha is a freshwater lake situated in the eastern rift valley of Kenya. Only five species of fish are present, all of which have been introduced. They are Oreochromis leucostictus, Tilapia zillii, Micropterus salmoides (largemouth bass), Barbus amphigramma and Poecilia reticulata (guppy). The first three of these form the basis of an important gill net fishery and bass are also taken by rod and line for sport. Barbus are occasionally caught by dip net. Actual and potential yields for the Lake Naivasha fishery are discussed and the fishery is shown to be under-performing. The feeding regimes of the commercially exploited fish were examined in the context of available food supply, in particular the benthic fauna. Small bass depend heavily on Micronecta and large bass mostly take crayfish. Detritus predominates in the diet of Oreochromis leucostictus and Tilapia zillii but the former also eats algae and the latter, Micronecta and macrophyte. Various food resources, especially the benthos, appear to be under-utilized and so it is possible that further species could be introduced to enhance the commercial fishery.

Towards the sustainability of the Lake Naivasha Ramsar site and its catchment

Article

Full-text available

Nov 2002

Sustainable development remains a pressing priority for the Lake Naivasha Ramsar site, as a matter both of long-term protection of the lake ecosystem and of the economic and social progress that depends upon it. This must be addressed at catchment-scale to protect the `ecosystem services' that constitute the region's primary resources. Sustainability principles highlight energy, fertilisers, pesticides and other aspects of chemical use, plastics, erosion and sedimentation, wildlife, water and socio-economic issues as central to sustainable development strategy, influenced by both intensive and subsistence farms across the catchment. Market forces and long-term self-interest provide compelling arguments for sustainable development, the delivery of which will depend upon education and the spreading of good practice, perhaps backed up by stewardship schemes. Alternatively, the adverse consequences of continued unsustainable practice are highly significant for the region.

Phosphorus inputs to Lake Naivasha, Kenya, from its catchment and the trophic state of the lake

Article

Full-text available

Nov 2002

The main river supplying Lake Naivasha, Kenya, the Malewa, drains a catchment given over to largely subsistence cultivation and animal husbandry. The lake itself is the focus for an intensive horticultural industry based upon irrigation from the lake. The Malewa, however, is relatively independent of the impact of industry, and so its contribution to eutrophication of the lake was evaluated. Two periods of study, a very wet-dry and a `normal' wet-dry season showed that the river contribution of phosphorus led to a total phosphorus loading of 1.4 g m–2 lake surface ann–1 in the very wet period compared to 0.2 in the `normal'. Chlorophyll `a' in the open water of the lake was significantly related to soluble reactive phosphorus. The lake is now eutrophic by normal limnological criteria.

Feeding of the exotic Louisiana Red Swamp Crayfish, Procambarus Clarkii (Crustacea, Decapoda), in an African tropical lake: Lake Naivasha, Kenya

Article

Full-text available

Nov 2002

The Louisiana red swamp crayfish, Procambarus clarkii, has had a major impact on aquatic ecosystems in Europe and America where it has been introduced for human consumption. In Lake Naivasha, where it was introduced in 1970, it is suspected of causing the complete disappearance of native floating-leaved and submerged plants by 1982 and again by 1996; recovery of submerged plants occurred in between, concurrent with a decline in P. clarkii. Examination of the feeding of P. clarkii by microscopic analysis of gut contents collected from the lake confirmed information from both its native and exotic ranges; that it is an omnivore with green plants and insects the predominant items recognised. Feeding experiments confirmed this omnivory, with a preference from herbivory over carnivory. They further showed the importance of native plants as opposed to exotic water hyacinth Eichhornia crassipes. It is concluded that P. clarkii could well have accounted for the observed elimination of native plant species in Lake Naivasha; the cyclical nature of populations of submerged plant species and of P. clarkii in inverse proportion to each other lead us to hypothesise that P. clarkii is a `keystone' species in the lake ecosystem.

Rainfall and drought in equatorial east Africa during the past 1

Article

Jan 2000
NATURE

Ecology and Management of Lake Naivasha, Kenya, in Relation to Climatic Change, Alien Species' Introductions, and Agricultural Development

Article

Dec 1990
ENVIRON CONSERV

Lake Naivasha is an important freshwater resource for Kenya's foreign-currency-earning agriculture and tourism, and for water-supply. It has always experienced extensive water-level fluctuations as a consequence of irregular rainfall patterns that are affected by continental-scale climatic events, and its communities — particularly of aquatic plants — were adapted to these changes.

Towards sustainable utilization of lake Naivasha, Kenya. Lakes Reserv Res Manag 2(3-4):231-242

Article

Sep 1996

I. O. Abiya

The current trend of utilization of the resources of Lake Naivasha poses serious threats to the fragile lake ecosystem and its biodiversity. The paper considers the dynamics of the changing lake ecosystem, imminent threats to, and the community-based approach towards the sustainable utilization of the lake. The sustainable use of the lake will not be fully realized without a sound management plan. There is a need to enact consolidated environmental legislation in Kenya, which will enable the strengthening of environmental conservation and the protection for sustainable utilization of natural resources.

Modelling water quality using soil and water assessment tool (SWAT)

Jan 2004

A T Berrihun

Berrihun, A.T. 2004. "Modelling water quality using soil and water assessment tool (SWAT)" Master's Thesis. ITC: Enschede, the Netherlands.

Lake Naivasha: Experience and lessons learned

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