Lake Naivasha, Kenya: Papers submitted by participants at the conference “Science and the Sustainable Management of Shallow Tropical Waters” held at Kenya Wildlife Services Training Institute, Naivasha, Kenya, 11–16 April 1999 together with those from add

205 Pages·2002·8.02 MB·English

by  Robert Becht

Lake Naivasha, Kenya
Developments in Hydrobiology 168
Series editor
H. J. Dumont
Lake Naivasha, Kenya
Papers submitted by participants at the conference "Science and the
Sustainable Management of Shallow Tropical Waters" held at Kenya
Wildlife Services Training Institute, Naivasha, Kenya, 11-16 Apri11999,
together with those from additional studies on the lake
Edited by
D.M. Harper1, R.R. Boar2, M. Everard3 & P. Hicklel
1 University of Leicester, U K.
2 University of East Anglia, U K.
3 Environment Agency, Reading, UK.
4The Environmental Agency, Kidderminster, UK.
Reprinted from Hydrobiologia, volume 488 (2002)
Springer-Science+Business Media, BV.
Library of Congress Cataloging-in-Publication Data
A C.LP. Catalogue record for this book is available from the Library of Congress.
ISBN 978-90-481-6272-7 ISBN 978-94-017-2031-1 (eBook)
DOI 10.1007/978-94-017-2031-1
Printed an acid-free paper
AII Rights reserved
© 2002 Springer Science+Business Media Dordrecht
Originally published by Kluwer Academic Publishers in 2002
No part of the material protected by Ihis copyright notice may be reproduced
or utilized in any form ar by any means, electronic or mechanical,
including photocopying, recording or by any information storage and
retrieval system, withoul written permission from the copyright owner.
v
TABLE OF CONTENTS
Preface
David M. Harper, Kenneth M. Mavuti vii
Jntroduction
The Lake Naivasha Management Plan - consensus-building to conserve an international
gem
Enniskillen ix-xii
Towards an understanding of human impact upon the hydrology of Lake Naivasha,
Kenya
Robert Becht, David M. Harper 1-11
The physical attributes of the Lake Naivasha catchment rivers
Mark Everard, Jacqueline A. Vale, David M. Harper, Hăkan Tarras-Wahlberg 13-25
Geochemical and physical characteristics of river and lake sediments at Naivasha,
Kenya
Hăkan Tarras-Wahlberg, Mark Everard, David M. Harper 27-41
Aspects of the biodiversity of the rivers in the Lake Naivasha catchment
Mark Everard, Anthony Kuria, Michael Macharia, Jacqueline A. Vale, David M. Harper 43-55
Chemical characteristics, with particular reference to phosphorus, of the rivers draining
into Lake Naivasha, Kenya
Nzula Kitaka, David M. Harper, Kenneth M. Mavuti, Nic Pacini 57-71
Phosphorus inputs to Lake Naivasha, Kenya, from its catchment and the trophic state
ofthe lake
Nzula Kitaka, David M. Harper, Kenneth M. Mavuti 73-80
Magnetic susceptibilities of lake sediment and soils on the shoreline of Lake Naivasha,
Kenya
R.R. Boar, David M. Harper 81-88
Phytoplankton community structure and succession in the water column of Lake
Naivasha, Kenya: a shallow tropical lake
David S. Hubble, David M. Harper 89-98
VI
Nutrient control of phytoplankton production in Lake Naivasha, Kenya
David S. Hubble, David M. Harper 99-105
Impacts of the C4 sedge Cyperus papyrus L. on carbon and water fluxes in an African
wetland
M.B. Jones, S.w. Humphries 107-113
The dynamics and ecology of exotic tropical species in floating plant mats: Lake
Naivasha, Kenya
C.S. Adams, R.R. Boar, D.S. Hubble, M. Gikungu, D.M. Harper, P. Hickley, N. Tarras-Wahlberg 115-122
Organochlorine and organophosphorus pesticide concentrations in water, sediment,
and selected organisms in Lake Naivasha (Kenya)
S.M. Gitahi, D.M. Harper, S.M. Muchiri, M.P. Tole, R.N. Ng'ang'a 123-128
Feeding of the exotic Louisiana red swamp crayfish, Procambarus clarkii (Crustacea,
Decapoda), in an African tropical lake: Lake Naivasha, Kenya
Andrew C. Smart, David M. Harper, FranQois Malaisse, Sophie Schmitz, Stephanie Coley,
Anne-Christine Gouder de Beauregard 129-142
Distribution and abundance of the Louisiana red swamp crayfish Procambarus clarkii
Girard at Lake Naivasha, Kenya between 1987 and 1999
David M. Harper, Andrew C. Smart, Stephanie Coley, Sophie Schmitz, Anne-Christine Gouder
de Beauregard, Rick North, Chris Adams, Paul Obade, Mbogo Kamau 143-151
Population structure and secondary productivity of Limnodrilus hoffmeisteri (Claparede)
and Branchiura sowerbyi Beddard in the profundal zone of Lake Naivasha, Kenya
Phil Raburu, Kenneth M. Mavuti, David M. Harper, Frank L. Clark 153-161
Population changes in sympatric Great and Long-tailed Cormorants (Phalacrocorax
carbo and P. africanus): the effects of niche overlap or environmental change?
R. Brooks Childress, Leon A. Bennun, David M. Harper 163-170
Population fluctuations and their causes in the African Fish Eagle, (Haliaeetus vocifer
(Daudin» at Lake Naivasha, Kenya
David M. Harper, Maureen M. Harper, Munir A. Virani, Andrew Smart, R. Brooks Childress,
Rachel Adatia, lan Henderson, Bernard Chege 171-180
The status and future of the Lake Naivasha fishery, Kenya
Phil Hickley, Roland Bailey, David M. Harper, Rodrick Kundu, Mucai Muchiri, Rick North, Andy
Taylor 181-190
Conc/uding remarks
Towards the sustainability of the Lake Naivasha Ramsar site and its catchment
Mark Everard, David M. Harper 191-203
Hydrobiologia 488: vii, 2002.
"D .M. Harper, R. Boar, M. Everard & P Hickley (eds), Lake Naivasha, Kenya. Vll
Preface
The 18 papers assembled in this volume arose from research conducted at Lake Naivasha over the past two decades.
Most were presented orally at the international conference 'Science & The Sustainable Management of Shallow
Tropical Waters' held at the Kenya Wildlife Services Training Institute, Naivasha, in Apri! 1999. One-page sum
maries of ali the oral presentations were published as a UNESCO IHP Technical Document (Harper & Zalewski,
2001) and 26 full papers in Hydrobiologia, volume 458. Some papers here were added after the conference to make
a more complete picture of the ecology of this important freshwater lake.
The work achieved at Naivasha and its publication here is a testament to the forward thinking of three groups
of people - few of them trained as research scientists. In the first instance, a group of visionaries along the eastern
seaboard of the United States, led by Brian Rosborough, developed the idea of ordinary citizens investing in envir
onmental knowledge by supporting, with their own time, efforts and at their own expense, field research leading to
conservation. Thirty years on, the Earthwatch Institute supports 148 expeditions a year from a membership in 48
countries. The EWI has supported almost ali of the research described in this volume, since 1987.
The second group of visionaries are those who were, or are now, resident in the Lake Naivasha area, who
have been working tirelessly to conserve the lake's ecosystem intact. Forty years ago the late Roger Mennel
made a laboratory on his lakeshore farm available to John Gaudet, Jap Kalff, John Melack and a succession of
Kenyan students for limnological research. The Wardens of the former Eisamere Conservation Centre - Jock &
Enid Dawson, John & Jane Carver, Angus & JiU Simpson and Velia & Tony Cam, took up this mantie from the
mid-1980s to 1999. By the time of the conference, Lake Naivasha had been given Ramsar status by the Kenya
government and the management of the site vested in the Lake Naivasha Riparian Association, due mainly to the
work of its Chairman (Lord Enniskillen) and Honorary secretary (Sarah Higgins).
The third group of visionaries are those people, ali over the globe, who see the degraded state that our planet is
in and play an active part trying to arrest and sometimes reverse its degradation. For most of us in the developed
world this means giving time and money but rarely changing our lifestyles. For those in the developing world it is
oft en changing their way of life and sometimes even sacrificing it. There are millions of these visionaries, but until
there are countless millions, the degradation will inexorably continue ali over the world.
This work is dedicated to those hundred or so Naivasha residents who have made this work possible by help,
encouragement and permissions and the thousand or so Earthwatch volunteers who have contributed by their hard
work to the data collection that finds an outlet in these pages. Finally, it is dedicated to the tens of thousands of
people in the Lake Naivasha region, who toil on the flower farms, struggle in the dukas, or stand for long hours
to sell newspapers in the streets, depending on the lake yet knowing nothing about it. At the time of writing this
editorial, Kenya has a new government which has already declared primary schooling will be free and appointed
Wangari Maathai, a prominent environmentalist as Assistant Minister of Environment and Natural Resources. The
prospects for all the 'wananchi' of Kenya to understand, care and protect their own resources for future generations
have suddenly improved markedly.
DAVID M. HAR PER KENNETH M. MAVUTI
Department of Biology Department of Zoology
University of Leicester University of Nairobi
England Kenya
Reference
Harper, D.M. & Zalewski, 2001. Science and the Sustainable Man
agement of Shallow Tropical Waters. Technical Documents in
Hydrology 46. UNESCO, Paris.
Hydrobiologia 488: ix-xii, 2002,
ix
D,M, Harper, R, Boar, M, Everard & P. Hickley (eds), Lake Naivasha, Kenya,
Introduction
The Lake Naivasha Management Plan - consensus-building
to conserve an international gem
In this introduction, as I said in my address to the conference where many of the following papers were first presen
ted, I want to take as my theme the synergy between the science and the management that we, the 'stakeholders' in
present-day jargon, are using to conserve Lake Naivasha. It is not just the science, but also the turning of science
into layman 's language and offering practical solutions to the everyday problems and potential confiicts of interest
facing the community in Naivasha, that is essential to the conservation process.
The definition of the word 'gem' is an object of great beauty or worth. Naivasha is both. Its conservation in its
beautiful state for future generations whilst utilising its worth to benefit present humankind is what the Management
Plan is aII about. Like anything of great worth, its security could be achieved by ring-fencing, protecting it by
'putting it in the bank'. The alternative is to make it of such value to the stakeholders that they ali play a part
in its conservation and feei they own it; and thus have no need to exploit or steal it. Ours is that latter objective.
Unfortunately to achieve it is a long-term task, and meanwhile damage can and will occur. That is why we advocate
a practical common-sense and damage limitation approach based upon the 'precautionary principle'.
The Lake Naivasha Riparian Association (LNRA) was jointly-awarded the 1999 Ramsar Wetland Conservation
Award (Ramsar, 1999a), given to 'those governments, organisations or individuals who have contributed signi
ficantly to the long-term and sustainable use of a wetland site, especially those initiatives which might serve as
inspirational or practic al examples for others'. Those are the significant buzzwords - 'conservation', 'sustainable
wise use', 'practical', 'inspirational' and 'examples'. A brief history of the Association will help to understand
why its efforts were rewarded this way (Ramsar, 1999b).
The LNRA was 70 years old in 1999. It was originally formed by the landowners around the lake to administer
an agreement with the government over the use of riparian land - the 'ecotone' - exposed by water level decline.
Naivasha is a shallow lake (see Hickley et al., 2002, for a depth map). Being a shallow lake with very gently sloping
shores, and being susceptible to large variations in depth between wet and dry cycles (see Becht & Harper, 2002,
for fiuctuations this century), the extent of the ecotone varies greatly even on an annual basis. We can experience a
water edge shift measured in kilometres and a variation in depth measured in metres, in the space of 6 months. The
riparian land is naturally very fertile with volcanic/lacustrine soils and subsurface water, so the agreement with the
government of the day was that the landowners around the lake could use the exposed land below their riparian
boundary (arbitrarily chosen as the level the lake attained in 1906) (Fig. 1) for grazing, cultivation and access to
the lake only. No permanent buildings were allowed, no claims against the government in the event of fiooding
would be entertained and the landowners themselves through their Association would arbitrate any disputes over
boundaries between one and another.
Unfortunately the agreement has proved not to be sustainable in the long term because of certain shortcomings,
though in other respects it was a unique and enlightened agreement, which gave a true sense of ownership of the
resource to the immediate community. It is undoubtedly that which has sustained the lake to date and prevented the
worst abuses that could otherwise have occurred. Its shortcomings were in the lack of definitions and the omissions.
For example, what is a 'permanent building', what is 'cultivation'? 'Should there have been a buffer strip, beyond
which no human activity is allowed?' 'Should livestock be allowed free access to the littoral zone and to water
direct from the lake?' None of this was spelled out, but as the size of human population began to increase rapidly,
livestock numbers increased. Horticultural technology, with its attendant use ofpesticides and fertilisers has grown
dramatically over the past two decades, so these errors and omissions became serious in the extreme. Landowners
who interpreted cultivation to mean the establishment of long-term intensive crops with a 1O-I5-year life did so
x
Figure 1. Lake Naivasha in November 200 1. The RAM SAR site boundary is the lake road.
apparently legitimately. Inevitably there followed problems of cultivation too c10se to the lake and the erection of
structures to protect their investment from ftooding by the rising lake, thus interfering with natural processes. Those
who believed that plastic greenhouses were not permanent buildings put them up, apparently legitimately, and soon
we had whole segments of the ecotone devoid of vegetation and covered with plastic. The labour-intensive ftower
industry developed and with it the need for housing, water and latrines - especially near the workplace on the
shoreline!
Trying to solve these problems in the absence of effective environmental legislation on the one hand and in
a developing country desperately short of jobs, foreign exchange and socio-economic development on the other,
was potentially a recipe for ecological disaster. Fortunately, a combination of enhanced scientific knowledge,
enlightened ftower growers and agriculturalists in Naivasha, together with a more discerning market in the de
veloped world which increasingly demands 'environmentally-friendly' production methods for ftowers, fruits and
vegetables, has since enabled us to begin to address these shortcomings in the agreement, by negotiation with the
government.
In the late 80s we foresaw the problem that we were going to face and also recognised one major weakness of
the situation. Although I have emphasiscd the scnsc of ownership imparted by the riparian agrcement - the rcality
is that true ownership of the ecotone remains with thc govemment. In a country such as this, wherc productive land
is scarce and the population is rapidly increasing, 'govemment land' means available land, land to be parcelled
out for politica! favours. In the absence then of much environmenta! awareness among politicians, little consensus
xi
among stakeholders about conservation, this was a dangerous situation which required delicate consensus-building
to prevent either the land being declared a protected area or being invaded by land-hungry allotees, neither of
which could be sustainable. The Association was a welI-established organisation, with an interest in the resource,
a diverse membership representing a cross-section of society, and a common interesl in maintaining the quality
and quantity of lake water. We set out to build on these strengths. 1 believe that we were also fortunate to have the
ideal conditions of climate, soils and water for ftower-growing. For ali its potential to destroy the lake, the industry
is contributing greatly towards sustainable utilization of such a valuable resource. In the absence of the industry, 1
believe more abuse and more fragmented development would have occurred and would have been more difficult to
contain.
So, in the early 1990s, the LNRA resolved to put in place a management plan for the lake which would promote
voluntarily adopted, sectoral, codes of con duct, within an overall strategy with the objective of ensuring that alI the
human activities then represented around the lake could be sustained (quite independently of Ramsar's 'wise use'
principles of which we were not aware at that time).
Even so, there was a wealth of research on which to draw, so our tirst priority was to assemble a synopsis of
that research in a single, readable, document, achieved in late 1993 (Goldson, 1993). The second phase was the
writing of the management plan, which took approximately 2 years, involving a steering group representing a wide
cross-section of interests from the LNRA and beyond, involving the community at large. During this second phase
we worked closely with the Kenya Wildlife Service to have Lake Naivasha nominated as Kenya's second Ramsar
site, achieved in Apri11995.
We always knew that the third, implementation, phase of the process would be the most difficult. We were set
back by nearly a year after the plan was written because some important stakeholders believed that their livelihoods
were threatened not only by the plan but also by the designation as a Ramsar site. These difficulties were overcome
by dialogue and continued consensus-building. The plan was finalIy approved by stakeholders and received the
official approval of government through the District Development Committee, being subsequently presented to His
ExcelIency The President in 1997 when the implementation phase officialIy began (LNRA, 1999).
Water must urgently attain its true worth as a limited and highly valuable natural resource. For the vast majority
of humans, water is the very basis of their lives. The daily trudge for miles to fetch it from unreliable and often
polIuted sources in rural areas or broken taps and running sewers in urban sprawls is their reality. Society has to
change that, as we have to ensure that Naivasha does not become just another such polIuted source.
Conservation for its own sake without grassroots education is only a rich man's game. Education for alI in
environmental conservation, understanding the long-terrn effects of polIution, awareness of best practices and a
sense of responsibility for the world around is a long-terrn programme. In Kenya, huge numbers of people are
educated at village and community level where, although they may lack sophisticated know1edge, they perhaps
have a better opportunity than their educated peers to appreciate the natural world. In future they will need to
be raised relying more on the resources around them. We must educate the educators to emphasize environmental
issues and give them due weight in school curricula. Dr Richard Leakey, KWS Director, in opening this conference,
said that humans had a right to live in a healthy environment - equal to their right to education and good health. 1
would go further, as 1 do not believe that humans have rights without corresponding responsibilities. To attain the
right to live in a healthy environment we - everybody - has a responsibility to care for it.
Our lessons must be realistic. We cannot teach the negative aspects of, Of enforce control of, tree cutting and
charcoal burning in developing countries where alternative energy sources are either unavailable or expensive.
We heard during our conference about papyrus brickettes, fuelwood crops using fast-growing local trees such
as Sesbania sesban, but they must be made more affordable and the communities must have a strong sense of
ownership of the resource in order for it not to be over-exploited. The human population in Naivasha has expanded
from 25000 to 250000 over the last 15 years, largely through immigrant labour for the horticultural industry.
They need energy to cook with and food to eat - a practical problem. The forest cover remaining in the Naivasha
catchment, the papyrus around the lake and the biodiversity of the lake itself are under threat unless we address
these issues. The stakeholders must be alIowed to benefit directly from their water resources - only then will they
look after them. This is an integral part of the management plan, whose scope extends into the catchment.
The Management Plan has already shown progress, in the metering of irrigation water, voluntary retreat from
riparian land, adoption of drip-feed irrigation amongst some stakeholders. But there is stiH a long way to go. We