Assessment of Impacts of Urbanization on Surface Water Quality, The Case of Keha River, Gondar Town
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Date
2018-10
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
This study assessed the impacts of urbanization on surface water quality and identify the sources
of pollution on Keha River in Gondar town. Urbanization and anthropogenic activities are the
key factor causing water quality degradation as we go downstream along Keha River.
Based on Keha watershed land use land cover in1999,2004,2006 and 2017, it is shown
that there is significant land use change of the bare land, grassland and agricultural land
converted into urban land use and Keha River water quality has deteriorate in the past 15
years. The critical source of pollutions are industries like Moha soft drink industry,
Gondar hospital, Kedame Gebeya Commercial market, a lot of hotels and restaurants
among others. To analyze the river water quality fourteen (14) different strategic sampling
sites were selected. The analysis consisted of in situ and laboratory analysis of samples
using standard methods. The result indicated that the range of PH (5.9-8.97mg/l),
Conductivity (142-1231 us/cm), Turbidity (8-1072 NTU), Dissolved Oxygen (7.4-2.1mg/l),
BOD (4.1-217mg/l), TDS (102-1298mg/l), Alkalinity (89-508mg/l), Total Hardness(103283mg/l),
Iron(0.15-0.76),
Chromium(0.02-0.42),
Manganese(0.02-3.9),
Phosphate(1.3732.7mg/l),
Nitrate(35.4-178mg/l), Total coliform counts(2.9-495) and E.Coli counts (2273.8) for
rainy
and
dry
seasons.
At
all
sampling
sites
except
upstream of
Keha
River
the
Physico-
chemical
and
bacteriological
results
of
water
samples
were
above
the
Ethiopian
and
WHO standard limit indicated that Keha River was polluted. Except upstream of
Keha River, at all sites the Dissolved Oxygen (DO) is less than 5 mg/l that is below the
WHO and Ethiopian minimum standard limit. High nitrate and phosphate cause of
eutrophication, high total coliform and high E.coli lead to water borne disease and the
death of the communities especially children because some people like the daily laborers
and street children were used for drinking this polluted River within the study area. It is
therefore concluded that the river in the study area is polluted and not fit for domestic use.
It is recommended that the water of Keha River should not be used directly for domestic
purposes. It is also recommended that an IWRM approach be used in order to solve the
pollution problem. Keha River health restorative work is require for multiple importance
such as ecosystem regeneration, water quality improvements, reduce any negative impacts
on the water resources and aquatic life of Keha River.
Description
Keywords
Gondar City, Impacts of Urbanization, Keha River, Surface water quality