






























East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, Issue. 2, 13-28

Effect of Land Use Activities on Water Quality and Vegetation Cover Change in Nsooba - Lubigi
Wetland System, Kampala City

Charles K.Twesigye1*, Kennedy Igunga1 and Ritah Nakayinga1

1 Department of Biological Sciences, Faculty of Science, Kyambogo University, P.O. Box 1, Kyambogo,
Kampala, Uganda

KEYWORDS:

Agriculture;

Built environment;

Public health;

Pollution;

Wetland

ABSTRACT

An assessment of the effect of land use activities on water quality and vegetation cover
change in Nsooba - Lubingi Wetland System in Kampala city was conducted between July
and October 2020. In order to achieve the set objectives, twelve locations were selected
from the Nsooba - Lubingi Catchment. The physico-chemical characteristics of water
along the catchment area were determined by standard analytical methods. The average
values for Total Dissolved Solids across all the land-use types of wetland, built up areas
and agriculture were lower than the National Standard (750 mg/l). A similar pattern of the
land-use  was observed for the parameters Total phosphorous, Biological oxygen demand,
Chemical oxygen demand, Total suspended solids and Total organic carbon, where the
observed average values were all below the National Standards of 10 mg/l, 50mg/l,
70mg/l, 50mg/l and 50mg/l, respectively. The Total Nitrogen average value for built-up
areas (11.27 mg/l) was higher than the national standard of 10 mg/l while the remaining
land use types of wetland (8.05mg/l) and agriculture (5.96mg/l) were below that of the
recommended standard. GIS and Remote sensing techniques were used to analyze high-
resolution satellite imagery captured during 1998, 2008 and 2018. Wetland coverage
declined by approximately 5 hectares (47.2% to 14.58%) from 1998 to 2018. Although
most of the measured parameters were below the National standard specified by the
Uganda National Environmental Management Authority apart from Total Nitrogen for
built-up areas, there is need for close monitoring of the water quality in Nsooba - Lubingi
catchment to ensure public health safety. The increased built-up environment in the
Nsooba - Lubigi wetland affects ecosystems services of the wetland. The buffer zones for
flood control and sewage treatment have been turned into built-up environment. The
results from this study suggest a need to protect the Nsooba - Lubingi catchment for its
important ecosystems services of flood control and sewage treatment.

INTRODUCTION

The world's growth metrics have been impacted
by unchecked expansion in a variety of human
undertakings, including industrial,

transportation, agricultural, and urbanization
(Gavrilescu et al. 2015 and Mishra et al., 2023).
Globally, water quality deprivation is one of the
main persistent, and greatly observable signs of
anthropogenic impacts. Surface water bodies

East African Journal of Biophysical and Computational Sciences

Journal homepage : https://journals.hu.edu.et/hu-journals/index.php/eajbcs
Hawassa University

College of Natural & Computational Sciences

Year 2021

Volume xx No xx

*Corresponding author:
Email: twesigyeck@yahoo.com +256-782353775 https://dx.doi.org/10.4314/eajbcs.v5i2.2S

 
Research article



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

14

such as reservoirs, river streams and lakes are
enormously vulnerable to primary discharges of
solid and liquid waste. Extremely dilute water
bodies, specifically in headwater regions are
vulnerable to impacts caused by atmospheric
deposition (acid rain) (Sasakova et al., 2018).

In developing countries, the changes in land use
are directly and indirectly related to pollution
challenges that include sewage, insecticides and
pesticides, greatly contaminated water quality,
principally near intensive agricultural areas and
urban industrial centers (Wang et al., 2015).
This alters the ecological landscape, severe
strain from anthropogenic encroachment as well
as consistent land filling activities for
reclamation, water drainage for agriculture and
livestock farming, human settlements, clay and
sand extraction, brick making, harvesting of
papyrus,  municipal and industrial waste
discharges, unsuitable and illegal solid waste
disposal (Peters et al., 205, Kayima et al.,
2018). In the natural ecosystem, heavy metal
concentrations differ, human activities alter the
distributions and natural cycles of metals
creating an unbalanced ratio in the metal cycle
leading to accumulation (Edokpayi et al., 2018).

Many studies of watershed microbiology focus
largely on the detection of indicator microbes
such as E. coli, enterococci, salmonella and
coliform bacteria and how these might indicate
potential risks to human health and
environment. Hawumba (2017) indicated that;
in Uganda, the leading causes of water quality
impairment is high nutrient (phosphorus and
nitrogen) discharge to the ground and surface
water bodies. The same author further added
that, whereas nitrogen is of principal
significance in affecting and preventing
eutrophication in marine environments,

phosphorous is the restraining nutrient in
freshwater (or non-saline) ecosystems.
According to Ding et al., (2015), studying the
correlation among water quality and land use
supports to ascertain primary stresses to water
quality which are predetermined for efficient
water resource and quality control since they
can be used to target key land use regions and to
incorporate pertinent methods to curtail
contamination discharges.

Similar studies on land use have indicated its
substantial impacts on water quality (Twesigye
et al.,2011). Deforestation, urbanization and
agriculture mostly alter land topography and
characteristics, surface runoff volume, upsurge
algal production, generate contamination and
reduce concentrations of dissolved oxygen in
water resources. According to Wang et al.
(2015), vegetation cover is an indicator that
assesses terrestrial environmental surroundings.
Minor alterations of vegetation structures of the
landscape inhibit ecological processes. The
increasing rates of land-use change over natural
habitats like wetlands, lakes, rivers have
resulted into the conversion of the natural
environment for agriculture, sand mining,
fishing and urbanization.  Any deterioration of
the natural vegetation raises the quantity levels
of particulate matter in water, and consequently
can directly and indirectly affect water quality
(Fierro et al., 2017).

According to Sebhatleab (2014), land use
change has triggered the decline in both soil
physicochemical and biological properties
depending on the classification levels across the
landscape and soil profile. Constant exposure of
top soil can attribute to long-term intensified
vegetation deprivation and start a process of
land pollution (Marinho et al., 2016). The



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

15

surface water flow from the upstream, as well as
the populous  slums of Kawaala, Kyebando,
Kalerwe, Bwaise, Kanyanya, Nansana and
Namungoona (Karabo, 2017). Due to
insufficient environmental policies like
development of the buffer zone to protect
drainage system, Nsooba - Lubigi drainage
system has and will continuously receive the
initial and direct trickle-down effect of the
visually and severely contaminated wastewater
from the up-stream storm water draining to the
channel as well as the Lubigi Sewage Treatment
Plant.

Additionally, Nsooba - Lubigi drainage system
has continuously been under serious pressure
emanating from human actions and
encroachment including unplanned land filling
for reclamation, water drainage for agriculture,
human settlements and livestock farming, use of
agricultural pesticides in management of crops,
sand and clay mining, brick making, the
harvesting of papyrus for handcrafts,
inappropriate solid waste disposal, municipal
and industrial effluent disposal and other forms
of discharges have led to pollution and
contamination of the drainage system thus being
a haphazard to  the environment and
surrounding community.

The area was selected as an ideal site because of
the urbanization levels (construction of northern
by-road), crowded settlements and the apparent
poor sanitation and management of waste water.
Further, Nsooba slaughter house also discharges
solid and waste water into Lubigi wetland,
creating severely contaminated wastewater from
the upstream Nsooba - Lubigi water drainage
stream and the Lubigi Sewage Treatment Plant.

correlation  between  land  use  activities  and  its
impact on soils involves  studying the drivers of
the  variations  in  soil  structure  and  help  in
illustrating  good  management  processes  to
prevent  desertification  and  attain  conservation
goals.

Limited  studies  have  been  conducted  to  study
the  overall  interactions  between  land  use  and
water  quality.  The  consequences  of
anthropogenic  activities  on  water  quality,  soils,
and  vegetation  cover  are  severe  and  call  for
sustainable  management.  This  study examines
the  relationship  between  land  use  and  water
quality  to  determine  the  microbial  and  physic  -
chemical  attributes  of  the  water, soils  integrity,
as  well  as  the  vegetation  cover  along  Nsooba  -
Lubigi  drainage  system.   This   study,therefore,
explores  the  effect  of  land  use activities
on  water  quality,  soil  and  vegetation cover on
Nsooba  -  Lubigi  drainage system.

MATERIALS AND METHODS

Study Area

The  study  area  lies  within  Nsooba  -  Lubigi
drainage  system,  stretching  from  Bukoto  hills,
the origin of  Nsooba  -  Lubigi  to Lubigi wetland
in  Namungona.  It  is  located  between  0°  21’N
latitude  and  32°  35’E  longitude,  in  Kawempe
Division, Kampala City.

The  discharge   from  the  surrounding
environment  to  Nsooba  -  Lubigi  drainage
system  is  about  220,000  m3/day  and  originates
from  the  daily  human  activities,  industrial  and
municipal  effluent,  automotive  and  mechanical
discharge,  rainwater  run-off,  surface  and  sub-



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

16

Figure 1: Study sites in Nsooba - Lubigi drainage system, Kampala City

Data Collection Tools and Methods

Land Use Land Cover Change Activities

Landsat-5 TM, Landsat-8, and Sentinel 2
images with a spatial resolution of 30m and 10m

for 3 years (2018, 2008, and 1998) were
downloaded from an open-source at no cost.
These were used for the spatial analysis of land
use activities and vegetation cover change in
Nsooba - Lubigi.

Table 1: Data specifications

Satellite Data MM/DD/YY PATH and Row Band Resolution Source
Landsat 5 (TM) 08/07th/1998 172,059 3,4,5 30m x 30m USGS
Landsat 7 (ETM+) 09/14th/2008 172,059 3,4,5 30m x 30m USGS
Landsat 8 (OLI/TIR) 10/07th/2018 172,059 3,4,5 30m x 30m USGS

A hand held GPS receiver was used for ground
verification in evaluating the five land use/
cover classes as indicated in Table 2.



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

17

Table 2: Land Use Land Cover (LULC) classification by Anderson method

Land use/cover classes Description
Agriculture Subsistence Farming: Mixed farming characterized by crops grown for

survival
Small scale farming Small Scale Farming: Mixed farming, single and multi farming, dry and

irrigated farming
Bare Land Land that is productive and unproductive with no developments activities

going on
Wetlands seasonal and permanent wetlands, swamps, bog
Built-up Areas Settlements like residentials, commercials, non-residentials, roads

As supervised classification was performed at
the study area, each class was calculated while
considering the pixel counts and total site (Table
2). Thus, categorizations were made based on
area coverage and presented in both hectares
and percentage. The five classes included
Forestry, Grassland, Wetlands, Settlement, and
Small scale farming. Percentages of classes
based on these results portrayed land use/land
cover events seen in the study area during 1998,
2008, and 2018 respectively.

Sampling Strategy

Water and soil samples were collected from the
field for further analysis. A minimum of 48
water samples and 36 soil samples were
gathered from 11 sites along Nsooba - Lubigi
drainage system. The sites were selected due to
the high anthropogenic activities (urbanization,
slaughterhouse, industries and road
construction) carried out within the wetland
area. A minimum of 4 sampling at each
sampling site were collected in Duran.
Parameters for analysis included pH, EC, TSS,
TN, TP, total coliform and E. coli, BOD and
COD. These constitute the major parameters in
measuring the degree of contamination of a
water body (Chapman, 1992; Longe and Omole
2008). All the samples were preserved at 4oC

using  a  sampling  cooler  box  and  transported  to
the  laboratory  for  analysis.  Sampling  was  done
between  08.00  am  and  05.00  pm,  the  time  of
peak  activities  at  the  Nsooba  -  Lubigi  drainage
system  in  July  2020  and  October  2020.  During
sample  collection,  sampling  containers  were
rinsed  twice  with  sampled  water  and,  labeled
and  then  taken  to  the  Ministry  of  Water  and
Environment  laboratory  in  Entebbe,  stored  in
the  refrigerator  while maintaining a temperature
of 4°C prior to analysis.

Water Pollutants

Water  samples  were  collected  between  July
2020  and  October  2020  in  two  sets  to  ensure
that the results obtained are more representative.
Each  set  consisted  of  24  samples  totaling  to  48
samples.

Analytical Procedures and Measurement

In order to assess the effect of land use activities
on   quality  of  water  and   vegetation   cover
of Nsooba- Lubigi  drainage  system,  physico-
chemical  properties  and  nutrients  loads  from
upstream  and  downstream  of  the  Kalerwe
abattoir  discharge  area  were  evaluated. The
physico-chemical  characteristics  were
determined  by  the  American  Public  Health



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

18

Association (APHA) standard analytical
methods of water analysis. HACH standard
method was used to determine nutrients
concentrations by using a DR 1900
spectrophotometer and a DRB 200 digester as
defined in the HACH procedure manual for
chemical and physical water quality. Total
suspended solids were analyzed using a
gravimetric method. The Galen Kamp oven was
used for drying at 105°C and a Mettlor Toledo
weighing scale was used for weighing.

Chemical Oxygen Demand was determined by a
standard HACH procedure using a DR 6000
spectrophotometer and DRB 200 digester as
described in the HACH procedure manual. A
volume of 2mls of the sample were put in the
COD vial and digested at 150 °C for 2hrs. The
vials were allowed to cool and COD was read.
BOD was analyzed using a BOD5 day test kit.
This was used for digestion and monitoring
oxygen changes.

Determination of pH & Electrical Conductivity

pH was photometrically analyzed using a
thermo scientific Orion star 3 machine whereas
Electrical conductivity was analyzed using an
Orion star A 222 conductivity meter.

Determination of Vegetation Cover Change

This was determined using Landsat8 and
sentinel 2. Landsat enabled the acquisition of
old satellite images of 2008 and 1998, whereas
sentinel facilitated the acquisition of satellite
image of 2018.

Data Analysis

To compare the parameters across land use
types, the data were subjected to a non-
parametric test known as Kruskal-Wallis H-test,
because it is more robust and requires smaller
samples sizes. The test compares medians
among k independent groups (k > 2) and is
formulated based on ranks rather than actual
observations (Daniel, 1990). The test is
generally robust to departure from normality
and homoscedasticity and is less sensitive to
outliers. Kruskal-Wallis H-test only indicates
that more than two groups are significantly
different. It cannot show which specific groups
of the independent parameters are statistically
different from each other. Dunn test was used to
determine which land use types were
statistically significantly different from each
other. Fisher’s exact test was used were the data
was categorical in nature and therefore difficult
to compute the median.

Image Acquisition

Re-classification process and change detection
analysis of various land-use land-cover classes
were performed by three Landsat satellite
images of 5 TM, Landsat 7 ETM+ and Landsat
8 OLI/TIR all acquired from path 172 and row
059 as indicated in Table1. The satellite imagery
data was downloaded from the United States
Geological Survey website (USGS)
(ftp://ftp.glcf.umd.edu/glcf/Landsat/WRS2 and
https://earthexplorer.usgs.gov/). After
downloading, the images were all geo-
referenced to the WGS 84 datum with the UTM
Zone 36N of the coordinate system. All satellite
data were analyzed by assigning per-pixel
signatures and segregating the land uses to 5
classes based on different landscape elements.



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

19

eight out of the nine physicochemical
parameters were positively skewed (skewness>
2.0) signifying the presence of large outliers.
These values for the parameters EC, TDS, TP,
TN, BOD, COD, TSS and TOC are 2.563,
2.700, 2.731, 2.996, 4.400, 6.808, 2.412 and
2.867 respectively. This implied that the median
was preferred to the mean as the measure of
central tendency of the data and for comparison
to the National Standards. The pH value of
0.966 was negatively skewed, signifying
accurate correlation.

According to Table 3, the EC values for wetland
(537.5 µs/cm), built-up areas (472.5 µs/cm) and
agriculture (272.50 µs/cm) remained below the
recommended threshold of 1000 µs/cm. The
average values for TDS across all the land-use
types of wetland, built up areas and agriculture
(309.00 mg/l, 352.00 mg/l and 155.00 mg/l
respectively) were lower than the National
Standard (750 mg/l). A similar pattern of land-
use types of wetland, built up areas and
agriculture was observed for the parameters TP
(0.84mg/l, 0.82 mg/l and 0.53 mg/l
respectively), BOD (5.75 mg/l, 14.00 mg/l and
8.75 mg/l respectively), COD (41.00
mg/l,49.50mg/l and 42.00 mg/l respectively),
TSS (25.00 mg/l, 42.00 mg/l and 10.00 mg/l
respectively) and TOC (16.70 mg/l, 20.50 mg/l
and 5.65 mg/l respectively), where the observed
average values were all below the National
Standards of 10mg/l, 50mg/l, 70mg/l, 50mg/l
and 50mg/l respectively. For TN, the average
value for built-up areas (11.27 mg/l) was higher
than the national standard of 10 mg/l while the
remaining land use types of wetland (8.05mg/l)
and agriculture (5.96mg/l) were below that of
the recommended standard.

The  delineated  classes  were:  Agriculture,  Bare
land, Wetland and Built up  Areas  (Table  2). For
each   of  these,  a designated  land  use/   cover
category  was  assigned  training  samples  by
defining  polygons  within  each  sites,  and
signatures  files  created  for  the  particular  land
use/  cover  categories  downloaded  from  the
satellite   imagery   taken   by   using   pixels
enclosed  by  polygons.  The  unsupervised
classification  was  performed  using  the  ISO
Clustering  Classification  method  which  was
followed  by  ground-trothing  to  guide  in  the
performance  of  the  Maximum  Supervised
Classification  for  accuracy  assessment.  All
classification  processes  were  executed  using
ArcGIS  10.2  as  explained  in  the  subsequent
paragraphs.

RESULTS

Impact  of  human  activity  on  the  water
quality

The  results  for  the  effect  of  land  use  activities
on  physico-chemical  composition  of  water
quality  are  presented  in  Table  3  and  shows  a
significant  correlation  between  land  use
activities  and  physico-chemical  composition  of
water. According to Table 3, the Kruskal-Wallis
test  showed  p  values  of  less  than  0.05  for  EC
(0.007),  TDS  (0.022),  pH  (0.022),  TN  (0.007),
BOD  (0.000),  TSS  (0.003)  and  TOC  (0.010),
indicating that they are significantly affected by
LUAs.  On  the  contrary,  no  significant
correlation  was  found  between  land  use
activities  and  TP  and  COD.  The  p  value  was
greater than 0.05 with TP recording a p value of
0.317  and  COD  with  0.203.The  results  from
descriptive  statistics  indicate  that  the  data  from



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

20

Table 3: Descriptive summary statistics and test for equality of medians for physic- chemical
parameters of water quality by land use
Parameter Land use Land

cover
No. of
obs. (n)

Median
(homogenous
groups**)

Kruskal-Wallis
test*

Overall
skewness

National standard
for waste water
discharge, NEMA

Electrical
conductivity
(µs/cm)

Wetland 8 537.50a H = 9.838
p = 0.007

2.563 1000 (µs/cm)
Built Up Areas 36 472.50a

Agriculture 4 272.50b

Total dissolved
solids (mg/l)

Wetland 8 309.00a H = 7.612
p = 0.022

2.700 750 (mg/l)
Built Up Areas 36 352.00a

Agriculture 4 155.00b

pH Wetland 8 7.30a H = 7.245
p = 0.027

0.966 5.0-8.5
Built Up Areas 36 7.20b

Agriculture 4 7.45a

Total
Phosphorus
(TP) (mg/l)

Wetland 8 0.84a H = 2.298
p = 0.317

2.731 5 (mg/l)
Built Up Areas 36 0.82a

Agriculture 4 0.53a

Total Nitrogen
(TN) (mg/l)

Wetland 8 8.05b H = 9.895
p = 0.007

2.996 10(mg/l)
Built Up Areas 36 11.27a

Agriculture 4 5.96b

BOD (mg/l) Wetland 8 5.75b H = 16.666
p = 0.000

4.400 50 (mg/l)
Built Up Areas 36 14.00a

Agriculture 4 8.75b

COD (mg/l) Wetland 8 41.00a H = 3.185
p = 0.203

6.808 70 (mg/l)
Built Up Areas 36 49.50a

Agriculture 4 42.00a

TSS (mg/l) Wetland 8 25.00a H = 11.896
p = 0.003

2.412 50 (mg/l)
Built Up Areas 36 42.00a

Agriculture 4 10.00b

TOC (mg/l) Wetland 8 16.70a H = 9.126
p = 0.010

2.867 50 (mg/l)
Built Up Areas 36 20.50a

Agriculture 4 5.65b

* National Environment (Standards for Discharge of Effluent into Water or Land) Regulations, 2020.

The effect of land use activities on the
vegetation cover in Nsooba - Lubigi drainage
system

The results for the effect of land use activities
on the vegetation cover for the years 1998, 2008
and 2018 are shown in Table 6..

Table 4: Land Use Land Cover Change from 1998 to 2018
Year 1998 2008 2018 Percentage

Change (%)Land Use Land
Cover

Area (Ha) % Area (Ha) % Area (Ha) %

Wetlands 6.93 47.21 4.05 27.59 2.14 14.58 -32.63
Agriculture 2.06 14.03 4.55 31 4.47 30.45 16.42
Bare land 2.13 14.51 1.05 7.15 1.04 7.08 -7.43
Built Up Areas 3.56 24.25 5.03 34.26 7.03 47.89 23.64
Total 14.68 100 14.68 100 14.68 100 0



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

21

The vegetation cover change from 1998 to 2018
was investigated for the four land use classes
namely; wetlands, agricultural activities, bare
land and built-up areas. According to results
from table 6 wetlands gradually declined from
47.21% in 1998 to 27.59% in 2008 and 14.58%
in 2018. Similarly, results for bare land showed
24.5% in 1998, and drastically dropped to
7.15% in 2008 and with no significant change
(7.08) in 2018. Seemingly, there was gradual
increase in agriculture and built-up areas by
14.03% in 1998 to 31% in 2018 and slowed
growth of 30.45% in 2018; and 24.25% in 1998
to 34.26% in 2008 and 47.89% in 2018. The
increase in built-up could have resulted into
reduced agricultural activities. The Land
use/land cover changes and vegetation cover for
the years 1998, 2008 and 2018 are shown in
Figure 2. LULC types such as Agriculture and
Built-up Areas have shown a notable increase
for the last two decades (from 1998-2018).

Land use land cover, a, b, c in1998, 2008,2018

Table 4 shows that, the total land area of the
study area was 14.68ha with a variation in land

use land cover change of the study area. The
dominant land use type was wetlands with an
area of 6.93ha (47.21%), followed by built up
areas at 3.56ha (24.25%). Both agriculture and
bare land showed minimal changes having
2.14ha (15.51%) 2,23ha (14.03%) of the land
use land cover respectively.

The analysis indicated that the surrounding
environment within Nsooba - Lubigi drainage
system in 2008 shows an increase in built up
areas 5.03ha (34.26%) and agriculture 4.55ha
(31%), these are the major anthropogenic
activities that result to contamination of water
quality and degradation of the Nsooba - Lubigi
wetland. There was a deliberately declined to
4.05ha (27.3%) as well as a significant decline
in bare land to 1.05ha (7.15%) resulting from
urbanization of the city centre.

It was observed that in 2018 the built up areas
consistently increased to 7.03ha (47.89%),
followed by 4.5ha (30%) of the total land use
and the natural vegetation cover especially
wetlands to 2.14ha (14.6%) and bare land at
1.03ha (7.08%) respectively.



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

22

Figure 2. Land use/land cover changes and vegetation cover

current land uses and activities. The previous
style of land use prevailed on both sides of the
Nsooba - Lubigi drainage system in the form of
road structures, communication networks,
settlements (planned and unplanned), and
farmlands. Evidence shows that the land and
vegetation cover has deliberately changed
compared to the past years. The Nsooba -
Lubigi drainage system has been seriously
affected by mainly human activities evidenced
by the on-going developments of the multi-
trillion road construction of the Kampala-
Entebbe express way for easy accessibility to
the Entebbe international airport which has
greatly affected the natural vegetation cover
thereby endangering the species diversity within
the study area.

The physico-chemical Parameters that were
analyzed in water include, Electrical
conductivity, Total dissolved solids, pH, Total

Land use land cover change

The high levels of built up areas at 23.64% and
agriculture  to  16.43%  of  the  total  percentage
land  use  change  between  2018  and  1998  meant
intensive  pressure  is  on  the  natural  resources
especially  the  wetlands  thereby  altering  the
water  quality  levels  to  -32.63%  between  2018
and  1998,  leading  to  expansion  of  urban
agriculture along and on marginal lands as well
as encroachment into protected  Nsooba  -  Lubigi
wetland.

DISCUSSION

While  determining  the impact  of  land  use
activities  on  water  quality  and  vegetation  cover
along  the  Nsooba  -  Lubigi  drainage  system,  it
was noticed that there are various activities  and
variations  in  past  land  use  as  compared  to  the



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

23

nitrogen, Total phosphorous, BOD, COD Total
suspended solids and Total organic carbon.
These were selected because they bring about
severe pollution and eutrophication if not
controlled or regulated which subsequently
impacts on the receiving ecosystem. Electrical
conductivity and Total dissolved solids
contribute to an ion influx which consequently
increase the saltiness of the water. This makes it
hard for the water born species to survive. pH,
on the other hand increases the alkalinity or
acidity of the water hence affecting the aquatic
life since they have specific pH in which they
survive. Total nitrogen and total phosphorous
are nutrients that bring about excessive growth
of the algae and the other green plants in the
water. This overtime inhibits direct light
penetration into the water and also inhibits
atmospheric re-oxygenation of the water which
consequently leads to suffocation of the fish and
other water borne species.

Further, land use activities in the study area
range from agriculture which includes animal
husbandry, horticulture, floriculture in the
Lubigi wetland, road construction, settlement
both planned and unplanned. Construction of
northern bypass has attracted more development
and population increase, this later led to creation
of slums in the wetlands for example Bwaise
and Kalerwe. National water and sewerage
cooperation has also constructed a sewage
treatment plant which encroached on the
vegetation cover of Lubigi wetland. All these
land use activities have led to degradation of the
wetland and loss of vegetation cover.

The effect of land use activities on the
physico-chemical properties of water

Figure 2 presents the Median (homogenous
groups**) of  EC, TDS, pH, TP, TN, BOD,
COD, TSS and TOC parameter values for the
land use activities. Figure 2 revealed that EC
and TDS were significantly impacted by land
use activities while COD, TTS and TOC were
moderately impacted. On the contrary, pH, TP,
TN and BOD were minimally impacted by land
use activities. Further, wetlands and built-up
areas presented the highest significant impact on
water quality, specifically EC and TDS, while
agriculture presented the lowest impact on water
quality and this could have been attributed to the
low farming activities carried out in the
sampling areas. Despite, the substantial effect of
LUAs on the water quality, all the EC, TDS,
pH, TP, TN, BOD, COD, TSS and TOC
parameter values for wetland, built-up areas and
agriculture activities were below the National
Standard for wastewater discharge set by
National Environmental Management Authority,
2020. This indicates that the results from
wetlands, built-up areas and agricultural areas
have minimal impact on the water quality.

The agriculture activity recorded the lowest EC
compared to built-up areas, which further
increased significantly in the wetlands. Similar
trends were obtained by Wachu (2018) who
presented that EC is highest in urban sites
compared to cultivated areas and forested areas.
The studies concluded that high EC
concentrations in wetlands is due to the
increased input of ions from industrial effluents
including car garages in Masanafu and
slaughterhouse in Kalerwe and domestic
wastewater. This conquers with the findings
attributed by Ochuka et al. (2019); who stated



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

24

moderate concentrations. This is also supported
by moderate concentrations in TOC from both
the wetland and built-up area activities. This
similar trend was also observed in the study
conducted by Özdemir et al. (2022)who
indicated that wastes from agricultural and
tourism activities in the field of study could
affect nitrogen and its derivatives.

Built-up areas presented the highest TSS and
this could be attributed to poor waste
management practices through littering and
discharge of unhealthy effluent from both
domestic and industrial activities. This is in
agreement with the studies conducted by Grimm
et al. (2005) and Shafie et al. (2017) who
highlighted that bare soil at building sites has
frequently resulted in large sediment inputs to
the drainage streams through rainfall runoff
events. The studies further indicated that the
extent of fine particulate was generally higher in
drainage streams around residential areas.

Other physico-chemical parameters including
BOD, COD TSS and TOC were moderately
high though below the National Standard, as
observed within the sampling areas. This clearly
shows that the high values could be attributed to
the undigested materials and animal solid waste
released from the Nsooba slaughterhouse. It
therefore implies that there is need for huge
amount of oxygen to synthesize all of these
organic materials into CO2 and water, which in
turn, cause high concentrations of COD and
BOD within the study area which could clarify
on the linear correlation between solids, COD
and BOD. This is in line with Hawumba (2017)
who stated that, the subsequent highly
concentrated discharge further adversely affects
the water quality of Nsooba channel as detected
by the increase in COD and microbial overload,

that anthropogenic activities such as application
of  agro-chemicals  and  waste  disposal  are
associated to higher EC in built-up areas.

In  regard  to  TDS,  the  concentrations  from
wetlands,  built-up  areas  and  agriculture  were
attributed  to  different  minerals  dissolved  in
water  which  include  potassium,  sodium,
magnesium,  bicarbonates,  these  can  be
connected to numerous other compounds which
can  be  water  contaminants  as  well.   However,
the  results  of  this  study  differs  from  recent
studies  conducted  earlier  within  the  drainage
system  by  Hawumba  (2017)  and  Ochuka  et  al.
(2019)  who  stated  that increased  concentration
of  TDS  results  in  noxiousness   through
heightened salinity  and  change  in   the  ionic
composition, influencing water  taste,  odour,
colour  and hardness. Water with TDS less than
600  mg/L  is  considered  pleasant; nevertheless,
extremely  low  TDS  reduces  the  flavor  of
drinking water.

The  average  values  of  pH  obtained  under  the
three  land  uses  fell  within  the  acceptable  range
of the national standard (5.0-8.5), signifying that
land-use  did  not  impact  the  water  pH.  Total
phosphorus  (TP)  had  negligible  impact  on  the
water quality, since the activities indicated very
low  quality  characteristics  in  comparison  to  the
national  standard.  This  could  have  been
attributed  to  the  low  BOD  levels  that  are
recognized to favor phosphorus discharge to the
freshwater  ecosystem  (Shafie  et  al.,  2017).  It
was  observed  that  Total  nitrogen  (TN)  is
moderately higher in all the 3 activities (though
below the national standard). Large increases in
organic  matter  from  wetland  areas  and  built-up
areas  (domestic  -  household  wastewater,
sewage,  detergent  waste,  etc.)  areas  might  have
led  to  an  increase  in  the  factors  affecting



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

25

revealing of significant nutrient quantities. The
sedimentation of some suspended solids, and the
mineralization of the organic loads as the water
flows away from the discharge points, should
partially describe the reduction in COD linked
to what other researchers have studied.

The effect of land use activities on the
vegetation cover

From Table 4 it was observed that built-up areas
and agriculture are the activities with the lowest
stability as they are developing activities in the
drainage system. This means that the transitions
of wetlands and bare lands types are oriented
towards urbanization and developing farming
activities. The percentage changes for wetlands,
agriculture, bare land and built-up areas
between 1998 and 2018 were observed to be -
32.63%, 16.42%, -7.43% and 23.64%
respectively as shown in table 4.

Further, it was observed that Nsooba - Lubigi
drainage system has been subjected to a gradual
process of reclamation and presently
experiences some of the most dangerous threats
and pressures, especially on the wetlands. The
sites around the drainage system, including
Nsooba channel and Lubigi wetland are
observed as major sites for urbanization due to
their proximity to the city center and industrial
district. The land use land cover (LULC) results
showed that Nsooba - Lubigi drainage system
was under several anthropogenic uses including
industrialization, increased agriculture, road
construction among others has increased the rate
of loss of vegetation cover. This is agreement
with Twesigye et al. (2011) who stated that
increased development such as urbanization and
industrialization, and other anthropogenic
practices  have led to the decline in vegetation

cover and its loss. Kayima et al. (2018) also
presented that rapid urbanization coupled with
increasing population growth are one of the
major driving factors of land use along Nsooba -
Lubigi drainage system. This proportionately
relates to Ding et al. (2015) who elaborated
that, in most  urbanized areas, land use largely
contributes to nitrogen and phosphorus
emanating from point source and non-point
source pollutants. Ribolzi et al. (2011 found that
most urban households are the common point
source to pollution in waste water
contamination, these contain pathogens which
harbor low dissolved oxygen conditions in
ground water supply leading to high metal
concentration in the wetlands and other aquatic
plant life.

Urbanization has additionally stretched to
water-resistant areas larger volumes of runoff.
Impervious rainfall runoff drains all types of
pollutants including point and non-point source
pollutants into rivers, which intensifies nutrients
concentrations into surface waters. The strategic
location of Nsooba - Lubigi drainage system
means that it offers an exclusive and significant
set of amenities to the residents within Bukoto,
Kyebando, Bwaise and Kawempe among others.
It serves as a buffer through which much of
Kawempe division's and part of Kampala
industrial and domestic effluents pass before
being discharged into River Mayanja which
eventually drains into River Kafu. Partially
treated sewage from NWSC Lubigi treatment
plant is mixed with the untreated wastewater
present in the Nsooba Channel before entering
the Lubigi wetland.

The current rise in settlements around Nsooba -
Lubigi drainage system especially in the areas
of Bwaise, Kalerwe, Kyebando and Makerere



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

26

among others is largely due to the high demand
for affordable accommodation by people who
work in the motor vehicle garages, Kalerwe
market and other markets around, petrol station
fuel attendants and small companies located
within Kawempe division. This is in line with
Zhang et al. (2011), who stated that
macroeconomic activities such as
industrialization and other businesses,
contributing to the growth of GDP often require
large areas also contribute to the transition of
forest/shrub land/grassland into buildup areas.
These results are in agreement with Omagor and
Barasa (2018) who reported that the wetland
extent was narrowing at a high rate due to
settlements. Similar trends in the degradation of
wetlands in Kampala city have been reported by
Warsame et al. (2022) and Karabo (2017). The
study by Karabo further reported that  the buffer
zones/spaces for flood control, sinking
sediments, silt, nutrients, pollutants, toxins and
sewage treatment have been turned into built-up
environment which explains the growing
problem of flooding and water quality in the
wetland catchments (Karabo, 2017).

A significant number of low income earners
find affordable and cheap temporal housing
along Nsooba - Lubigi drainage system and
wetland. Some of the residents around
Masanafu, Sentema, Namungoona and Bulaga
settlements depend on harvesting of papyrus
materials from Lubigi wetland as a way of
making the ends meet. The degraded natural and
cultural characteristics of the Nsooba channel
and Lubigi wetland show lack of clear channel
management policies. The location of Nsooba -
Lubigi drainage system makes it suitable for
providing exceptional and important ecological
services to the residents of Kawempe division
and Kampala City at large. Nsooba - Lubigi

drainage system is consequently meant to play
an important role in preserving the quality of
both water supply and open waters. This
signifies that areas made of urbanization, bare
land, as well as farming activities are
characterized by a significant population size
that could be partly contributing to water quality
and soil quality deterioration in the area.

CONCLUSION & RECOMMENDATION

The analytical concentrations of land-use types
of wetland, built up areas and agriculture was
observed for the parameters EC, TDS, TP,
BOD,COD , TSS, TOC , where the observed
average values were all below the National
Standards of 1000 µs/cm, 750 mg/l, 10mg/l,
50mg/l, 70mg/l, 50mg/l and 50mg/l
respectively. For TN, the average value for
built-up areas was higher than the national
standard of 10 mg/l while the remaining land
use types of wetland and agriculture were below
that of the recommended standard.

There was a significant decline in land coverage
for wetlands and bare land from 1998-2018
attributable to rapid urban development
involving infrastructural development, farming
activities and rapid population growth. Wetland
coverage declined by approximately 5 hectares
since 1998 which represents an average decline
of 2 hectares per decade. Bare Land was also
observed to have declined from 14.5% in 1998
down to 7% by 2018, signifying a rapid decline
of about 50% from 1998 to 2008. The
percentage changes for wetlands, agriculture,
bare land and built-up areas between 1998 and
2018 were observed to be -32.63%, 16.42%, -
7.43% and 23.64% respectively.



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

27

The Nsooba - Lubigi drainage system, with its
natural status is potentially susceptible to land
use changes attributed to anthropogenic
pressures. The physical and chemical
examination of water quality revealed that built
up area (Kalerwe) had the highest level of
pollution attributed to rapid population growth
and human activities including Nsooba
slaughter house that discharges untreated
effluents to Nsooba channel. The findings of
this research can offer scientific orientation for
land use management and water pollution
regulation as well as guide in the creation of
strategies for managing the water and other
natural resources. However, other factors
associated with water quality, such as the
weather, precipitation, and density of population
call for further research. From the findings of
this study, a degraded land cover pattern in the
Nsooba - Lubigi catchment is evident. The study
concludes that the people settling around
Nsooba - Lubigi Wetland System are victims of
the Lubigi wetland system environmental
degradation challenges and must be involved in
finding solutions to these problems. This calls
for the communities in the study area to assume
responsibilities in guiding and controlling its
development with the help of responsible
government institutions like NEMA and
research institutions. Our results suggest an
urgent need for formation of community based
management committees and by-laws to protect
the fragile wetland ecosystems in Kampala city
which are critical in biodiversity conservation,
flood control and waste wastewater treatment.

Acknowledgement

The authors are grateful to the Uganda Ministry
of Water and Environment (MWE) for
providing laboratory facilities for water

analysis. Denis Ekakoro is acknowledged for
GIS technical support.

References

Chapman D. 1992. Water Quality Assessments - A Guide
to Use of Biota, Sediments and Water in
Environmental Monitoring - Second Edition, 1996
UNESCO/WHO/UNEP. ISBN 0 419 21590 5 (HB)
0 419 21600 6 (PB)

Daniel T.C. 1990. Measuring the Quality of the Natural
Environment: A Psychophysical Approach. Am.
Psychol. 45(5) 633 – 637.

Ding J., Jiang Y., Fu L., Liu Q., Peng Q. and Kang M.
2015. Impacts of Land Use on Surface Water
Quality in a Subtropical River Basin: A Case Study
of the Dongjiang River Basin, Southeastern China.
Water 7(8): 4427-4445

Edokpayi J.N., Rogawski E.T., Kahler D.M., Hill C. L.,
Reynolds C., Nyathi E., Smith J.A.J., Odiyo J.O.,
Samie A., Bessong P. and Dillingham R. 2018.
Challenges to Sustainable Safe Drinking Water: A
Case Study of Water Quality and Use Across
Seasons in Rural Communities in Limpopo
Province, South Africa. Water (Basel). 10(2): doi:
10.3390/w10020159.

Fierro P., Valdovinos C., Vargas-Chacoff L., Bertrán C.
and Arismendi I. 2017. Macro invertebrates and
Fishes as Bio indicators of Stream Water Pollution.
In: Tutu H. (Ed) Water Quality
http://dx.doi.org/10.5772/65084, pp 428.

Gavrilescu M., Demnerová K., Aamand J., Agathos S.
and Fava F. 2015. Emerging pollutants in the
environment: present and future challenges in bio-
monitoring, ecological risks and bioremediation. N
Biotechnol. 32፡ 147-156.

Grimm N. B., Sheibley R. W., Crenshaw C. L., Dahm C.
N., Roach W. J. and Zeglin L. H. 2005. N Retention
and transformation in urban streams. J. N. Am.
Benthol. Soc. 24(3):626 – 642.

Hawumba J. F. 2017. The Impact of Kalerwe Abattoir
Wastewater Effluent on the Water Quality of the
Nsooba Channel. Agri. Res. & Tech: Open Access J
6(1): https://doi.org/10.19080/artoaj.2017.06.555677

Karabo Q.C. 2017. Land use and land cover change in
Nsooba-lubing wetland system, Central Uganda
Masters Dissertation, Makerere University,
Kampala, Uganda

Kayima J. W., Mayo A. and Nobert J. 2018. Ecological
Characteristics and Morphological Features of the
Lubigi Wetland in Uganda. Environ. Ecol. Res. 6(4):
218–228. https://doi.org/10.13189/eer.2018.060402



East Afr. J. Biophys. Comput. Sci. (2024), Vol. 5, No. 2, 13-28

28

Longe E.O. and Omole D.O. 2008. Analysis of pollution
status of River Illo, Ota, Nigeria. Environmentalist
28: 451–457.

Marinho F. P., Mazzochini G. G., Manhães A. P., Weisser
W. W. and Ganade G. 2016. Effects of past and
present land use on vegetation cover and
regeneration in a tropical dryland forest. J. Arid
Environ. 132: 26–33.

Mishra R.K., Mentha S.S., Misra Y. and Dwivedi N.
2023. Emerging pollutants of severe environmental
concern in water and wastewater: A comprehensive
review on current developments and future
research. Water-Energy Nexus 6: 74-95.

Ochuka M. A., Ikporukpo C. O., Ogendi G. M. and
Mijinyawa Y. 2019. Spatial Variability in Physico-
Chemical Parameters of Water in Lake Baringo
Catchment, Kenya. Curr. World Environ. 14(3):
443–457.

Omagor A. and Barasa B. 2018. Effects of Human
Wetland Encroachment on the Degradation of
Lubigi Wetland System, Kampala City, Uganda.
Environ. Ecol. Res. 6(6): 562-570.

Özdemir N., Perktas M. and Döndü M. 2022. Evaluation
of Surface Water Quality Parameters by Multivariate
Statistical Analyses in Northern Coastal Line of
Gökova Bay (Muğla, Turkey) . ADÜ ZİRAAT
DERG, 19(1): 81 – 91

Peters N.E., Meybeck M. and Chapman D.V. 2005. 93 :
Effects of Human Activities on Water Quality.
Water Quality and Biogeochemistry. Encyclopedia
of Hydrological Sciences. Edited by M. Anderson.
John Wiley & Sons, Ltd.

Ribolzi O.,  Cuny J., Sengsoulichanh P., Mousque C.,
Soulileuth B., Pierret A., Huon S. and
Sengtaheuanghoung O. 2011. Land Use and Water
Quality along a Mekong Tributary in  Northern Lao
P.D.R. Environ. Manage. 47: 291–302

Sasakova N., Gregova G., Takacova D., Mojzisova J.,
Papajova I., Venglovsky J. and Kovacova S. 2018.

Pollution of Surface and Ground Water by Sources
Related to Agricultural Activities. Front. Sustain.
Food Syst. 2:42. doi: 10.3389/fsufs.2018.00042

Sebhatleab M. 2014. Impact of land use and land cover
change on soil physical and chemical properties: a
case study of Era-Hayelom Tabias, Northern
Ethiopia. Land Restoration Training Programme
http://www.unulrt.is/static/fellows/document/Sebhatl
eab2014.pdf

Shafie M. S., Wong A., Harun S. and Fikri A. 2017. The
use of aquatic insects as bio-indicator to monitor
freshwater stream health of Liwagu River, Sabah,
Malaysia. J. Entomol. Zool. Stud. 5(4): 1662-1666.

Twesigye C. K. Onywere S. M. Getenga Z. M. Mwakalila
S. S. and Nakiranda J. K. 2011. The Impact of Land
Use Activities on Vegetation Cover and Water
Quality in the Lake Victoria Watershed. The Open
Environmental Engineering Journal 4: 66-77.

Wachu C. M. 2018. Effects of Land Use and Seasonality
on the Distribution of Mayflies and Water Quality
Along Thika River, Kenya. Nairobi: Kenyatta
University. MSc. Thesis.

Wang H., Wang T., Zhang, B., Li F., Toure B., Omosa I.
B., Chiramba T., Abdel-Monem M. and Pradhan M.
2014. Water and Wastewater Treatment in Africa -
Current Practices and Challenges. Clean - Soil, Air,
Water 42(8): 1029–1035.

Wang J., Wang K., Zhang M. and Zhang C. 2015.
Impacts of climate change and human activities on
vegetation cover in hilly southern China. Ecol. Eng.,
81: 451–461.

Warsame A., Luyiga S. and Akiyode O. 2022.Assessing
Wetland Degradation in a Growing Urban Area:
Case of Nsooba in Kampala, Uganda. KIU J. Eng.
Sci. Technol. 1(1): 1 – 6.

Zhang W. Ren L. L. Yang X. & Jiang S. 2011. The
impact of land use and land cover changes on runoff
in a semi-arid River basin. IAHS-AISH Publication,
350: 38–44.


	INTRODUCTION
	MATHEMATICAL MODEL FORMULATION
	The modified mathematical model
	Model formulation

	QUALITATIVE ANALYSIS OF THE MODIFIED MODEL
	Well-posedness
	Steady state
	Basic reproduction number
	Local stability of disease free equilibrium
	Global stability of disease free equilibrium
	Endemic equilibrium point
	Local stability of endemic equilibrium
	Bifurcation analysis
	Sensitivity analysis

	NUMERICAL SIMULATIONS AND DISCUSSION
	EXTENSION OF THE MODIFIED MODEL INTO AN OPTIMAL CONTROL
	Optimal protection and hospitalization using modified model
	Existence of an optimal control
	The Hamiltonian and optimality system

	Numerical simulations of optimal control problem
	Optimal control comparisons and strategies

	CONCLUSION
	INTRODUCTION
	PRELIMINARIES
	Intuitionistic Fuzzy Set
	Operations over Intuitionistic Fuzzy Sets

	Multi-objective programming problem

	MATHEMATICAL FORMULATION OF PROBLEM
	Intuitionistic Fuzzy Multi-objective Linear Decision-Making Problem
	Intuitionistic Fuzzy Goal Model of IF-MOLDMP

	PROPOSED SOLUTION METHOD
	 Extended Yager-membership function in the IFDE
	Develop a new intuitionistic fuzzy (IF) aggregation operator
	The intuitionistic fuzzy goal programming method
	Interactive Penalty Function Method (IPFM)

	ALGORITHM FOR PENALIZED IFGP METHOD
	NUMERICAL EXAMPLE
	RESULTS AND DISCUSSION
	CONCLUSION
	INTRODUCTION
	MATHEMATICAL MODEL FORMULATION
	The modified mathematical model
	Model formulation

	QUALITATIVE ANALYSIS OF THE MODIFIED MODEL
	Well-posedness
	Steady state
	Basic reproduction number
	Local stability of disease free equilibrium
	Global stability of disease free equilibrium
	Endemic equilibrium point
	Local stability of endemic equilibrium
	Bifurcation analysis
	Sensitivity analysis

	NUMERICAL SIMULATIONS AND DISCUSSION
	EXTENSION OF THE MODIFIED MODEL INTO AN OPTIMAL CONTROL
	Optimal protection and hospitalization using modified model
	Existence of an optimal control
	The Hamiltonian and optimality system

	Numerical simulations of optimal control problem
	Optimal control comparisons and strategies

	CONCLUSION

