INTRODUCTION
1.0 BACKGROUND OF STUDY
Availability of fresh water is increasingly becoming limited due to pressure from human
population expansion, modern agriculture to boost yields and meet increasing demand for food,
industrialization, poor watershed management that includes encroaching of riparian land and
raised demand of water per household for domestic uses (Weldemariam, 2013). At present,
approximately one-third of the world's people live in countries with moderate to high water
stress and the worldwide freshwater consumption increases six fold between the years 1900 and
1995 more than twice the rate of population growth, thus, many parts of the world are facing
water scarcity problem due to limitation of water resources coinciding with growing population
(United Nations Environmental Programme, UNEP, 2002).
Many people in developing countries of the world still rely on untreated surface water as their
basic source of domestic water supply. This is so because either there is an incessant supply of
potable water or inadequate water supply systems. At the global level, irrigation water for
agriculture is the biggest single user (about 70% of water use), followed by industry (23%) and
domestic uses (8%) (Sherbinin, 1998). If “green water” is added to the mix (water that feeds rain
fed crops), then crop production far and away outstrips other water uses. As demand for food
increases with growing populations and changing tastes (including growing demand for animal
versus vegetable protein with its far greater demands for water), it is expected that water
diversions for agriculture will only increase.
This problem is exacerbated in rural areas. Today, humanity is estimated to use 26% of terrestrial
evapotranspiration and 54% of accessible runoff (Postel et al., 1996). Falkenmark and Widstrand
(1992) established benchmarks for water stress of between 1000 and 1700 m3 per person, water
scarcity of between 500 and 1000 m3 per person, and absolute scarcity of less than 500 m3 per
person. Northern and southern Africa and the Middle East already suffer absolute scarcity. As
population grows and water resources remain more or less constant, many countries in the rest of
Africa are projected to fall below 1000 m3 per person (Engleman et al., 1998).
Globally, fresh water comprises 2.5 % of the total water mass with 68.7% of the water being in
ice form, 29.9% in aquifers as underground water and 0.26% in lakes and rivers. All these
,sources are susceptible to pollution hence reducing water potability (Carpenter et al., 2011). It is
fundamental to the biochemistry of living organisms; ecosystems are linked and maintained by
water; it drives plant growth; it is habitat to aquatic species; and it is a major pathway of
sediment, nutrient, and pollutant transportation in global biogeochemical cycles. (Acreman,
1998).
The biggest threat to sustainable water supply in South Africa is the contamination of available
water resources through pollution (Marsh, 1864). Many communities in South Africa still rely on
untreated or insufficiently treated water from surface resources such as rivers and lakes for their
daily supply. They have no or limited access to adequate sanitation facilities and are a high risk
to waterborne diseases (Lindblade et al., 1996). Since 2000, there has been a dramatic increase in
the episodes of waterborne diseases in South Africa (Tiffen, 1994; Natl. Acad. Sci.,1963)
In some developed countries of the world, adequate supply of potable water and improved
sanitation facilities have been achieved. Strict environmental laws and monitoring for
compliance prevent undue pollution to freshwater sources. Good waste management
technologies and increased environmental protection awareness have contributed immensely to
the success story. This has resulted in fewer cases of waterborne diseases reported compared to
developing countries.
STATEMENT OF PROBLEM
Many people in developing countries of the world still rely on untreated surface water as their
basic source of domestic water supply. This is so because either there is an incessant supply of
potable water or inadequate water supply systems. At the global level, irrigation water for
agriculture is the biggest single user (about 70% of water use), followed by industry (23%) and
domestic uses (8%) (Sherbinin, 1998). If “green water” is added to the mix (water that feeds rain
fed crops), then crop production far and away outstrips other water uses. As demand for food
increases with growing populations and changing tastes (including growing demand for animal
versus vegetable protein with its far greater demands for water), it is expected that water
diversions for agriculture will only increase.
, This problem is exacerbated in rural areas. Today, humanity is estimated to use 26% of terrestrial
evapotranspiration and 54% of accessible runoff (Postel et al., 1996). Falkenmark and Widstrand
(1992) established benchmarks for water stress of between 1000 and 1700 m3 per person, water
scarcity of between 500 and 1000 m3 per person, and absolute scarcity of less than 500 m3 per
person. Northern and southern Africa and the Middle East already suffer absolute scarcity. As
population grows and water resources remain more or less constant, many countries in the rest of
Africa are projected to fall below 1000 m3 per person (Engleman et al., 1998).
Contamination of water sources leads to increased pH that affects mucous membranes,
causes water to taste bitter and gives water a corrosive nature; increased dissolved oxygen,
increases temperature of water and results in increased microbial activity (WHO, 2006). They
also noted that nitrates can also soak into the ground and end up in drinking-water. All these can
result into health problems that contribute to methemoglobinemia or blue baby syndrome disease
which causes death in infants. The fresh water that is needed for a clean water supply is limited
and the demand far exceeds the available supply due to increasing population and
industrialization (Behailu et al. 2018).
OBJECTIVE OF THE STUDY
The objective of this study is to review studies on the effect of human activities on surface water.
CONCEPTUAL FRAMEWORK: SUSTAINABLE DEVELOPMENT
This research is based on the concept of sustainable development. The word sustainability means
the ability to exist continually, to comfort, and to nourish. Sustainable means continuing without
lessening (Flint et al., 2002). Development means improving or bringing to a more progressive
state, such as in our economy. Thus, sustainable development means working to enhance the
potential of human productivity without damaging or undermining society or the environment
(Flint, 2004). Sustainable Water Management is a critical component of sustainable
development, and accounts for similar issues as sustainability. Mays (2006) defined Sustainable
Water Management as meeting current water demand for all water users without impairing future
1.0 BACKGROUND OF STUDY
Availability of fresh water is increasingly becoming limited due to pressure from human
population expansion, modern agriculture to boost yields and meet increasing demand for food,
industrialization, poor watershed management that includes encroaching of riparian land and
raised demand of water per household for domestic uses (Weldemariam, 2013). At present,
approximately one-third of the world's people live in countries with moderate to high water
stress and the worldwide freshwater consumption increases six fold between the years 1900 and
1995 more than twice the rate of population growth, thus, many parts of the world are facing
water scarcity problem due to limitation of water resources coinciding with growing population
(United Nations Environmental Programme, UNEP, 2002).
Many people in developing countries of the world still rely on untreated surface water as their
basic source of domestic water supply. This is so because either there is an incessant supply of
potable water or inadequate water supply systems. At the global level, irrigation water for
agriculture is the biggest single user (about 70% of water use), followed by industry (23%) and
domestic uses (8%) (Sherbinin, 1998). If “green water” is added to the mix (water that feeds rain
fed crops), then crop production far and away outstrips other water uses. As demand for food
increases with growing populations and changing tastes (including growing demand for animal
versus vegetable protein with its far greater demands for water), it is expected that water
diversions for agriculture will only increase.
This problem is exacerbated in rural areas. Today, humanity is estimated to use 26% of terrestrial
evapotranspiration and 54% of accessible runoff (Postel et al., 1996). Falkenmark and Widstrand
(1992) established benchmarks for water stress of between 1000 and 1700 m3 per person, water
scarcity of between 500 and 1000 m3 per person, and absolute scarcity of less than 500 m3 per
person. Northern and southern Africa and the Middle East already suffer absolute scarcity. As
population grows and water resources remain more or less constant, many countries in the rest of
Africa are projected to fall below 1000 m3 per person (Engleman et al., 1998).
Globally, fresh water comprises 2.5 % of the total water mass with 68.7% of the water being in
ice form, 29.9% in aquifers as underground water and 0.26% in lakes and rivers. All these
,sources are susceptible to pollution hence reducing water potability (Carpenter et al., 2011). It is
fundamental to the biochemistry of living organisms; ecosystems are linked and maintained by
water; it drives plant growth; it is habitat to aquatic species; and it is a major pathway of
sediment, nutrient, and pollutant transportation in global biogeochemical cycles. (Acreman,
1998).
The biggest threat to sustainable water supply in South Africa is the contamination of available
water resources through pollution (Marsh, 1864). Many communities in South Africa still rely on
untreated or insufficiently treated water from surface resources such as rivers and lakes for their
daily supply. They have no or limited access to adequate sanitation facilities and are a high risk
to waterborne diseases (Lindblade et al., 1996). Since 2000, there has been a dramatic increase in
the episodes of waterborne diseases in South Africa (Tiffen, 1994; Natl. Acad. Sci.,1963)
In some developed countries of the world, adequate supply of potable water and improved
sanitation facilities have been achieved. Strict environmental laws and monitoring for
compliance prevent undue pollution to freshwater sources. Good waste management
technologies and increased environmental protection awareness have contributed immensely to
the success story. This has resulted in fewer cases of waterborne diseases reported compared to
developing countries.
STATEMENT OF PROBLEM
Many people in developing countries of the world still rely on untreated surface water as their
basic source of domestic water supply. This is so because either there is an incessant supply of
potable water or inadequate water supply systems. At the global level, irrigation water for
agriculture is the biggest single user (about 70% of water use), followed by industry (23%) and
domestic uses (8%) (Sherbinin, 1998). If “green water” is added to the mix (water that feeds rain
fed crops), then crop production far and away outstrips other water uses. As demand for food
increases with growing populations and changing tastes (including growing demand for animal
versus vegetable protein with its far greater demands for water), it is expected that water
diversions for agriculture will only increase.
, This problem is exacerbated in rural areas. Today, humanity is estimated to use 26% of terrestrial
evapotranspiration and 54% of accessible runoff (Postel et al., 1996). Falkenmark and Widstrand
(1992) established benchmarks for water stress of between 1000 and 1700 m3 per person, water
scarcity of between 500 and 1000 m3 per person, and absolute scarcity of less than 500 m3 per
person. Northern and southern Africa and the Middle East already suffer absolute scarcity. As
population grows and water resources remain more or less constant, many countries in the rest of
Africa are projected to fall below 1000 m3 per person (Engleman et al., 1998).
Contamination of water sources leads to increased pH that affects mucous membranes,
causes water to taste bitter and gives water a corrosive nature; increased dissolved oxygen,
increases temperature of water and results in increased microbial activity (WHO, 2006). They
also noted that nitrates can also soak into the ground and end up in drinking-water. All these can
result into health problems that contribute to methemoglobinemia or blue baby syndrome disease
which causes death in infants. The fresh water that is needed for a clean water supply is limited
and the demand far exceeds the available supply due to increasing population and
industrialization (Behailu et al. 2018).
OBJECTIVE OF THE STUDY
The objective of this study is to review studies on the effect of human activities on surface water.
CONCEPTUAL FRAMEWORK: SUSTAINABLE DEVELOPMENT
This research is based on the concept of sustainable development. The word sustainability means
the ability to exist continually, to comfort, and to nourish. Sustainable means continuing without
lessening (Flint et al., 2002). Development means improving or bringing to a more progressive
state, such as in our economy. Thus, sustainable development means working to enhance the
potential of human productivity without damaging or undermining society or the environment
(Flint, 2004). Sustainable Water Management is a critical component of sustainable
development, and accounts for similar issues as sustainability. Mays (2006) defined Sustainable
Water Management as meeting current water demand for all water users without impairing future
