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Despite their importance, wetlands have remained unprotected and they are exploited beyond what they can endure. The main objective of the study was to establish the land use effects on conservation of the Lake Ol’Bolossat watershed. The study was conducted in 10 villages, by systematic random sampling of 60 households and purposive sampling of key institutions such as KWS, KFS, NEMA and KALRO. Household questionnaires were issued to sample households, while interviews were held to establish environment issues in the study area. Direct observation transects walks and photography revealed that there was human encroachment, crop and livestock production and quarrying in the basin. Lake and runoff water were analyzed for both physical and chemical parameters. The samples were analyzed for pH, Mn, COD, TDS, TSS, K, P, Nitrates, EC, Total Nitrogen and Ammonia.
The results showed that runoff water was polluted before it flowed into the lake. The concentration of minerals in lake water was lower than that of the runoff water, an indication that contamination originated from surrounding farms. Water usage and proximity from the lake were significantly different at 95% confidence interval, hence most members of the community near the watershed rely directly on lake. Interviews indicated that the wetland degradation such as water pollution was based on land utilization. The study established that watershed conservation is affected by land use by the neighboring communities. Agrochemicals (30%), clearing vegetation (7%), water abstraction (16%), quarrying (3%), land fragmentation (12%), population growth (11%), poverty (12%) and others (9%) impacted the lake negatively. Water abstraction, drying of bore holes and land use were significantly different at 95% confidence interval. It is recommended that conservation of the lake ought to be enhanced through community participation and other stakeholders to manage, restore and preserve Lake Ol’Bolossat catchment.
Keywords: Conservation; Land use; Water quality and Watershed
Globally, the wetlands cover about 26% of the earth’s surface and in Kenya, they cover about 2-3% of her land surface, . Seemingly small geographic extent, wetlands provide some of the most critical ecosystem services to many communities in the rural areas and are indispensable to the very survival, health and welfare of human beings and biodiversity. They are crucial in attainment of the MDGs and the vision 2030 goals. They control floods by soaking up and storing excess water . The wetlands have been recognized as world heritage sites since the convention on wetlands was adopted in 1971 in Iranian city of Ramsar. Wetlands are areas of marsh, fen, peat, or water, whether natural or artificial, permanent or temporal, with water that is static or flowing, fresh ,brackish or salty, including areas of marine water, the depth of which at low tide does not exceed 6metres .
Wetlands are highly productive ecosystems being only second to the tropical rainforests. Wetlands perform many func
tions that maintain the ecological integrity of the systems and provide many vital services that are important for the general public such as agriculture, tourism, industry, and biodiversity conservation, social economic and cultural activities. Kenya has a variety of wetlands that stretch from coastal and marine wetlands to inland freshwater lakes, rivers, dams and swamps as well as the saline lakes of the rift valley system, constructed wetlands in irrigation schemes and sewerage treatment systems and the mountain bogs, peat and glacier lakes (EMCA).
However, due to lack of effective management mechanisms and proper appreciation of their true worth, wetlands have been subjected to severe pressure and through rapid unsustainable activities, conversion and over- exploitation of their resources at an alarming pace. The pressures to wetlands have been exacerbated by catchment degradation and pollution leading to proliferation of invasive species. The results have been detrimental and even catastrophic in some areas of the country. For example,
flash floods in western Kenya have become more common, severe
and destructive as there are no wetlands to hold back any
massive overland flow, leading to loss of property, destruction of
infrastructure and damage to crops . The Kenya government
has recognized the importance of wetlands and their contribution
to her gross domestic product .
The original inhabitants of the study area were Masaai pastoralists
and the land belonged to the community as there was
no individual land ownership. Crop farming was done on very
small scale without use of chemicals. The pastoralists used livestock
for meat and did not harm wild animals . The rules were
centered on the preservation of sacred areas for traditional rituals
and not for commercial benefits . Currently, the dominant
community members are the Kikuyu and they have converted
part of the wetland into agricultural farms Lake Ol’Bolossat is
a high attitude wetland located in Satima escarpment where
streams and springs that feed lake, flow from the Aberdare Ranges
through Satima escarpments and pass across farms. The farming
practices lead to Lake Siltation and landslides. Soils eroded
from the neighboring farms reduces the water storage capacity
of the lake. The lake water is moderately saline but fresh water
from springs and streams dilute the water before it is discharged
into Ewaso Narok River which exits the lake in the north. Kenya
has an obligation to regulate land use for sustainability of wetlands,
G.O.K (2009). However, through county environmental action
plan (CEAP), National Environment Management Authority
is making policies in collaboration with community to conserve
Despite their valuable functions, wetland resources are often
regarded as wasteland and are degraded through conversion to
agricultural, settlement and industrial development, hence deterioration
of the environment quality and little or no concern has
been shown in conservation of the same. Sustainability of Lake
Ol’Bolossat is threatened by the land use transformation resulting
to loss of ecologically important species such as pollinators
and biological control agents, . The state of equilibrium between
various entities has been disturbed and disharmony has
resulted from lack of integration between conservation and utilization
of natural resources, ACCORD (2002).
There is an urgent need, therefore, to step up management
interventions in order to reverse the negative trends. The study
sought to reveal the negative land use impacts in the area and
hence a critical need for improved land uses planning to curtail
further decline of Lake Ol’Bolossat. Although watershed
degradation processes may occur without human interference,
Stocking & Niamh (2000), accelerated degradation is commonly
caused as a result of human intervention in the environment.
Human induced factors causing deterioration of watersheds (are
such as population growth and urbanization, poverty, overgrazing,
pollution, biodiversity, erosion and land use changes) [6-8].
Socio-economic factors, including poverty, land fragmentation;
low standard of living and earning are cited as drivers contributing
to an increased risk of watersheds,  due to differences
in land uses. Land ownership influences socio-economic and
political position of different groups of people. Land issues and
conflicts occurs and are related to poverty, inequality and land
reformation processes. Contestations over land are most noticeable
among the poor, who lack alternative means of supporting
their livelihoods, UNDP (2006), therefore lack of resources
conservation. Transition from forest to another agricultural use
leads to significant impact on topsoil resistance and resilience
. For most wetlands, soil erosion by water is the most common
process causing sedimentation. There is a distinct linkage
between erosion and watershed conservation, and these are accelerated
by deforestation, overgrazing, and the cultivation of
unsuitable land .
Lake Ol’Bolossat watershed has been affected by anthropic
disturbances . In the headwater catchments of the central
Kenya, a prevalent cause of land degradation is unplanned deforestation
to allow for human settlements and subsistent agriculture
.In the highlands of Nyandarua, the ubiquitous land-use
changes are believed to be the major cause of the dwindling volumes
of Lake Ol’Bolossat, which has recently been declared an
endangered water body by the regional government of Kenya.
So far, few studies have been carried out on the spatio-temporal
lands cover changes possibly affecting the size of Lake Ol’Bolossat
largely hence lack of reliable in-situ data. The largest herbivores
in the basin are the hippopotamuses. The cattle grazing in
the basin are abundant in the dry season. Hippopotamus population
density is 3.6 animals per Km2. which is the highest in
Kenya. The grazing activities influence the structure and composition
of the natural vegetation which supports many herbivores
and grasshoppers. Continued overgrazing maintains a low grass
biomass. Trampling by animals affects ground nesting birds negatively.
The other water animals include waterfowls, ducks and
geese which are indicators of environmental quality. The areas
with high concentration of different species of birds are also rich
in diversity of other animal species as well.
Human activities affect the water availability by increasing
storage capacity and by draining wetlands, . The natural
input to sub surface water is from rivers and streams. Basic
household water requirement is estimated at solicitors/person/
day. The environmental usage is non-consumptive, but it reduces
water availability for other purposes. Recreation water is mostly
found in reservoirs and it is required in small amounts. The
Ol’Bolossat catchment area includes springs and streams which
feed the lake and support livelihoods, but the lake is characterized
by freshwater scarcity supposedly due to climate change
and high evapotranspiration . Accumulated of organic matter
and silt from the surrounding farmland has contributed to
water pollution. The water level fluctuates from zero to 2.5metres
depending on the rainfall, surface run off and seepage from
the basin. There is domestic and agricultural pollution due to
unsustainable farming practices which lead to occurrence of waterborne
According to the forest Act 2005, KFS has the responsibility
of managing Kenyan Forest. The law allows for collaboration
and participation of the local community living adjacent to the
forest in conservation of the forest in question. In return the
community earns a living through extraction of non-wood products.
The use of agrochemicals has led to bioaccumulation in fish
and pose health risk to human as well as fish death and causes
extinction of some species. In 1992 the Fisheries department
established that turbidity of Lake Ol’Bolossat was not suitable
for fresh water fish though mud fish could do well in those conditions.
Habitat loss and degradation ruin the fisheries through
water abstraction, removal of vegetation for development and
agriculture. Communally owned resources experience problems
when being shared such as unequal sharing of resources, dissimilar
priorities, location of the resource, dissimilar cultures and
unequal representation in the management .
Generally, the region of Lake Ol’Bolossat has a history of colonial
settlements when the major land uses were large scale
livestock rearing and crop production. In the recent past however,
the area has gone through considerable land use transformations
under the national settlement fund trustees, resulting into
significant land subdivision and fragmentation, especially after
1993. Presently, the majority living in the area are small scale
farmers who grow subsistent crops and rear domestic livestock
on land parcels ranging from 0.5 to 8 acres. The human population
density of the area is approximately 202 per Km2.
Lake Ol’Bolossat is bordered by Ndaragwa, Ol kalou and Ol
joro orok sub counties. It is situated in a wedge-shaped Rift valley
floor sloping eastwards and northwards, known as Ongata
Pusi. Lake Ol’Bolossat is approximately 195 Km north of Nairobi.
It lies between latitudes 0o 09’S and longitudes 360 26’E in
Nyandarua county in the central part of Kenya (Figure 1). The
lake has a surface area of about 43Km2 and lies at an average
altitude of 340M above sea level. The entire catchment area of
Lake Ol’Bolossat, covers 4800Km2, encompassing Nyandarua
ranges, Satima Escarpment and Ndundori Hills, NEMA (2007).
The water flows northwards through Thompson Falls into the
northern part of Ewaso Nyiro River. In the lake basin it is dominated
by vertisols, NEMA (2007).
There is seasonal inflow of water from streams in the eastern
side and there are underground springs that replenish the lake in
the west. The lake is fed by streams from Satima escarpments on
the eastern side. There is seasonal water recharge in the south
and the lake supplies water to river Ewaso Nyiro in the north
NEMA, (2007). The mean annual rainfall of the area is about
980mm and increasing southwards and westwards. Rainfall is
bimodal, with long peaks between April and June and the shorter
peaks between October and November. The mean temperature is
23.50C with little monthly variations.
Field research was conducted between November and December
2015. The research methods used included actual sampling
and laboratory analysis of Lake Ol’Bolossat water and
runoff water. A questionnaire, informal discussions, direct observation
and focus group meetings were used to explore land uses
activities and farmers’ perceptions of effects related to land uses.
The samples, of both lake Ol’ Bolossat and runoff water, were
collected during morning hours (650F, mostly cloudy, wind, N at
4mph and humidity 100%) and evening hours (600F, light rain
showers, wind, NE at 0mph and humidity 100%), of the rainy
season of the project area.
Water samples were collected from different selected points
in the lake and other samples from runoff flowing towards the
lake. The following assumptions were made during water sampling:
i. Water samples would adequately represent the situations
ii. Sampling during the morning and evening hours would
cater for variation in pollution
iii. A minimum of two sampling points per site (lake and
flowing runoff) in different hours would take care of spatial
variation in pollution.
The samples were transported to the upper kabete laboratory
(UON) in 500ml plastic bottles. At the upper kabete laboratory
(UON), a general water characterization was carried out following
procedures described in a manual of standard methods for
examination of water samples . The parameters studied in clude nutrients ( Nitrates, Phosphates and Potassium), pH, Electrical
Conductivity(EC), Total Suspended Solids, Total Dissolved
Solids, Potassium, Manganese and Chemical Oxygen Demand
(COD). The water samples collected contained particulate organic
matter, requiring pretreatment or digestion before spectroscopic
analysis. The water samples were digested using 5ml nitric
acid (HNO3) for testing phosphates and 3.5ml sulphuric acid
for testing Chemical Oxygen Demand (COD). The sample was
brought to a slow boil and then evaporated to almost dryness 9
lowest volume possible-about 15 to 25 ml) on a hot boiling tube.
Heating was continued until digestion was complete which was
indicated by a light colored clear solution, followed by Flame
Atomic Absorption Spectrophotomer (FAAS).
Since Lake Ol’Bolossat is narrow and lies in a north-south
direction, it appears to form boundary between west and east.
To assess the community perception of impacts associated to
land use on wetland, a survey was conducted in 5 villages, 30
households respectively on both eastern and western side of the
lake using individual household questionnaire. The sample size
was randomly selected systematically, using an interval of twenty
based on how they lie in the basin and near the lake. Purposive
sampling of institutions was used to gather information from officers
in NEMA, KALRO, KFS and KWS about the land use around
the watershed and their effects. Interviews were used to collect
relevant information from key institutions and conservation
groups. Observations and photographs collected information
guided by checklist. Data collected from the FGD and questionnaires
was treated with utmost confidentiality.
Data collected was sorted, organized, conceptualized, refined
and interpreted using methods drawn from the constant comparative
analysis techniques. The strategy involved comparing
data, some of which were similar and others different in order
to develop conceptualizations of the possible relations between
various pieces of data. Data was analyzed using Statistical Package
for Social Sciences (SPSS) software and excel. Various data
sets such as land uses, quarrying, sources of income and other
variables were fed to the package. This information was generated
in form of percentages and presented using tables, graphs
and charts, upon which conclusions and recommendations were
(Figure 1) shows gender of respondents in percentage. The
household interviews revealed that there was almost equal gender
distribution since the sample comprised of 58%, females and
42% males as shown in Figure 1 below. This gender distribution
was attributed to the fact that the study area is relatively newly
settled with land being occupied by both genders as landowners.
Gender empowerment and promulgation of Kenyan constitution
2010 contributed to the almost equality in gender distribution.
According to , watersheds and gender has taken a proactive
approach to women’s greater involvement in water management.
(Table 1) From Table 1 participants had their ages distributed
from 20years old to over 52 years old. For easy presentation,
ages were grouped into classes of intervals of 15 years. It was established
that majority were aged between 20 to 35 years, while
the class of above 52 had lower frequency. This was as a result
of unemployment of youths therefore involving themselves with
activities such as quarrying and subsistence fishing in the lake.
Most of them who were involved in conservation complained
that they do not find any tangible benefits from their conservation
efforts (Figure 2).
Literacy levels of formal education considered in this study
area were primary, secondary and tertiary education. Most of the
respondents in the study area had secondary level of education
with frequency of 66% as shown in Figure 2. This ascertains that
most of the residents have formal education and it is expected
they understand all those activities that contribute to degradation
within the basin and hence they are expected to practice
the possible conservation measures. Low levels of education and
high levels of illiteracy are usually associated with little knowledge
on the importance of conservation and hence little or no
adoption of the various recommended conservation methods.
Ignorance is also associated with illiteracy whereby, due to low levels of education residents are ignorant of the recommended
conservation measures as highlighted by the government policies
on catchment conservation (Table 2). Education level and
gender were not significantly different at 95% confidence interval
Therefore, the two variables did not affect each other, meaning
the respondents had knowledge of the conservation of the
lake irrespective of their education level and gender. Figure 3
shows different sources of income for the participants. Most
people in this area were farmers i.e. mixed farming and crop production
(22% and 3% respectively). This was a result of benefits
of wetland supporting agriculture such as water abstraction,
forage for the animals. As these people intensively got involved
in farming it was established that a great proportion (3%), also
did quarrying around the basin. However, accessibility of wetland
resources made most members of the community to rely on
watershed for their livelihood. The survey also established that
the natures of daily activities undertaken by the respondents
were also contributing to the catchment degradation (Plate 1).
As these people intensively got involved in farming it was established
that a great proportion (3%), also did quarrying around
the basin. This was an evidence of unemployment in the country.
However, accessibility of wetland resources made most members
of the community to exploit the resources for income.
The study established that the farming methods embraced
within the study area were intensive and resulted to topsoil
eroded during runoff causing gullies within the catchment
(Plate 2). This erosion has also been evident on the bounders
of the lake causing sedimentation and siltation hence reducing
its water holding capacity. This is evident as majority of the respondents
complained that the lake water usually changed color
during rain seasons as compared to dry spells. Settlement and
the development of agriculture can enhance erosion on the surfaces
of the watersheds .
The study established that various human activities had led
to degradation which included agrochemicals, clearing vegetation,
water abstraction, quarrying, land fragmentation, poverty,
population growth and other combined problems (Figure 4).
According to respondent’s response on what they felt caused
degradation 30% said that excessive use of agrochemicals was
the major cause of degradation as it had impact on water quality
due to sphere erosion. 16% of the respondents were of opinion
that water abstraction was also a threat to the lake riparian ecosystem,
which was practiced along the lake. Excessive agrochemicals
were as a result of intensive farming from the surrounding
farms. Several studies have demonstrated strong associations
between agricultural land use and alteration to wetlands . In
addition to nutrient transport, the loss of suspended sediment in
agriculture runoff is a major threat to water quality as particles
may carry pesticides, pathogens and other pollutants .
Agricultural (agro ecosystem) sources of disturbance can increase
loading of total nitrogen and phosphorous which affect
watershed [21,12]. Land was not used according to its suitability.
Current patterns of agriculture will continue to result in damage
to both quantity and quality of water resources . Conversely,
watershed with abundant human activities that increase the export of nutrients will more rapidly degrade water quality in
the receiving lake . Population pressure in natural resources
remains a key driver . The responses and observations indicated
that the community near the wetland is unprepared for dry
periods (Table 3). Hence most of them relied more on wetland
for water supply. They have no storage facilities for harvesting
rainwater, hence they fetch water from water points that they
share with livestock.
Water usage and proximity from the lake were significantly
different at 95% confidence interval; hence most members of
the community near the watershed rely directly on lake (Table
4). Most of respondents near the Lake were dependent on it for
source of water therefore most of them did not have water storage
facilities. Hence, affecting Lake’s capacity to function due to
excessive abstraction of water.
Plate 3 shows irrigation in the eastern side contributed to
pollution of the lake. This was as a result of poor irrigation methods
which involved excessive water supply on the farm hence resulting
to water overflow. However, leading to excessive abstraction
of water from the Lake.
The survey established that the major land tenure activity
was agriculture i.e. mixed farming, crop production and livestock
production. Water abstraction, drying of bore holes and land use
were significantly different at 95% confidence interval (Table 5).
Therefore, land use contributed to watershed degradation as a
result of excessive water abstraction for agricultural activities.
Of the respondents 14.7% were involved in crop production,
as compared to 51.7% who used their land for both crop
and animal production (Figure 5). This land use ventures were
found to seriously affect the wetland for some farmers grazed on
the riparian zone of the lake (Plate 4) hence affecting the water
quality and quantity. The activities on the land surrounding Lake
Ol’Bolossat were attributed by the ecosystem services provided
by the watershed. Most of them who were involved in conservation
complained that they do not find any tangible benefits from
their conservation efforts.
Livestock grazing practices can cause erosion and bank destabilization
as shown in Plate 4 . However, eutrophication
can be as a result of nutrients accumulation from livestock manure.
According to the sub county agricultural officer the type
of land tenure was also a contributing factor to the high rate of
destruction on the catchment (Figure 6) and this required an
urgent attention in order to address it. The survey established
that 51.7% of the land within the catchment was privately owned
as a result owner had a higher stake in determining the type of
farming to be undertaken. This affected the wetland and fragile
Water quality is a term used to describe the chemical, physical
and biological characteristics of water, generally in terms of
suitability for a particular use. The respondents indicated that
crop production was insufficient and intensive cultivation has
therefore been employed in order to increase crop production by
use of pesticides and chemical fertilizers. The agricultural practices
have negative impacts on the wetland by polluting water.
Water pollution can interfere usage of a wetland. The water quality
in the catchment area has declined over years. For instance,
there are cattle dips near the lake. Surface runoff was collected
from water channels flowing towards the lake at different day
hours. Plate 5 shows cattle dip which could be a source of pollution
through chemical leaching and runoff, therefore contaminating
the watershed. The lake water was found to be highly
contaminated and unfit for domestic use. The concentration of
nitrates, total suspended solids and total dissolved solids in the
lake water was lower than that of runoff water (Table 6). This
indicates that the concentration originated from activities associated
with the land use from the surrounding such as quarrying,
intensive farming, livestock grazing (Plate 1 & 2) but once
it enters the lake it’s diluted by clean water from streams and
springs. Livestock grazing practices can cause erosion and bank
destabilization, Borman et al. . Freshwaters are degraded
by increasing inputs of silt, nutrients and pollutants from agriculture
. Moreover, the irrigation in the eastern side curtails
flow of water into the lake, therefore contributing to pollution of
the lake. The ground water is slightly saline due to the nature of
The study did an in-depth research and established that
there was serious degradation; this destruction has negatively
impacted the lake thus leading to water decrease on the catchment.
The lake has been unable to perform its functions efficiently.
This has allowed grazing in the basin of the lake. Farming has also been going on along the riverine which has led to loosening
of top layer of the soil which is eroded during runoff on rainy
seasons. Moreover, water quality has been affected negatively.
Privately owned land has been used for intensive cultivation and
to some extent abstraction of water for irrigation hence leading
to decline in water quantity. The study concluded that Lake
Ol’Bolossat requires urgent measures to restore, conserve and
manage the watershed.
The study suggests various strategies towards restoration,
conservation and management of Lake Ol’Bolossat. Sustainable
land use practices and farming technologies such as organic
farming to minimize agro pollution and drip irrigation to avoid
water wastage. Oxidation ponds could be constructed to deal
with nutrients in the runoff water from farms; nutrients flow into
the lake will be reduced. The local community should be sensitized
on the various advantages of conservation of the watershed
through capacity building by training conservation groups and
Rainwater harvesting should be improved in order to provide
alternative sources of water for irrigation instead of abstracting
direct from the lake. Riparian reserves and buffer zones need to
be provided to remove people on the catchment and allow restoration,
such as massive livestock grazing. However, the Water resource
management authority needs to protect Lake Ol’Bolossat
from degradation by locating the cattle dips far away from water
sources in order to reduce pollution.
I would like to take this opportunity to thank everybody who
contributed to enabling me to write this research proposal successfully,
more specifically, my supervisor Dr. G.N. KARUKU, my
classmates and all my friends and family who assisted me in one
way or another. Most of all I would like to thank the Almighty God
for seeing me through this proposal writing process and guiding
me every step of the way. It is because of His mercies that I can
come this far.
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