Water resources management & hydroclimatic data analysis in transboundary river basins under the influence of climate variability & water abstraction : Nile river basin

Ahmed, Y

Abstract

Water is a vital component for developing nations, as it is important for human
consumption and domestic use, irrigation, and industry. The freshwater availability for
each country should be known or estimated to sustainably manage its available supply,
or its share of available water in case of transboundary basins during the subsequent
years. The freshwater availability in the present and the future is governed by two
factors: the effects of climate change or climate variability and the effects of human
induced factors. The climate change can be sensed from the increase or decrease of
precipitation, increase in temperatures, and increased prevalence of heat waves,
drought events and the degree of severity of the drought events in some areas and
increase in floods in other areas. The human induced factors can be witnessed in the
change of land use, damming the rivers and excessive water obstruction and
withdrawal.
The sustainable management of the available water resources is essential for future
generations and environmental resources, especially with the present and possible
future challenges in terms of increase in demand due to population growth and possible
changes in precipitation. The application of water resources management practices is
more difficult to achieve in transboundary river basins. Sustainable management could
be achieved by assessing the utilization of the water at a transboundary scale besides
studying the possible impacts of climate change and applying mitigation measures to
avoid water scarcity in downstream countries.
The problems facing transboundary river basins are very complicated and there is a
need to study the problems occurring due to the human interventions and climate change or climate variability, which will give a solid ground to determine how much
the river flow is being affected qualitatively and/or quantitively and try to find suitable
effective solutions for each of them.
In this thesis the case of the Nile river basin will be representative of several shared
river basins. The Nile river basin is third biggest river basin in the world and the second
largest basin in Africa after the Congo basin in terms of area. It is shared between
eleven countries and covers about 10% of African land.
This thesis aims to present an analytical framework to determine how the river
discharge has been affected by the influence of both climate variability and human
induced factors. The findings from this thesis can support better understanding of the
changes occurring in river discharge due to coupled impact of climate variability and
river damming. The study of the changes occurring in the river discharge due to climate
variability and human intervention can lead to better planning for sustainable
management practices of water resources in transboundary river basins especially in
arid and semi-arid regions.
River flows have different fluctuations in river discharge as a result of the influence of
the change in climate and human influence. The main aim of this research is to measure
how the climate variability and human intervention affect the river flow either as an
increase or a decrease in river discharge. The change in river discharge occurs based
on the degree of intervention and the climatic conditions. Thus, the relation between
the degree of human intervention and climate variability to the river discharge could
or might help in taking the optimum procedure in the sustainable management of water
resources, and help in negotiations between riparian countries to reach to a suitable treaty saving the rights of both upstream countries and downstream countries, and
establish effective measure(s) to mitigate the water scarcity crises.
The objectives are to analyze the river discharge reaching the downstream countries in
the past, and how the human induced factors and climate variability in terms of changes
in trend and the occurrence of drought events affected the river discharge.
This has been addressed by assessing climate variability in the study area. The research
includes the studying and choosing of the best metrological dataset for the areas with
scarce meteorological datasets. The analyses of precipitation data obtained from the
Global Precipitation Climatology Centre (GPCC) and detecting if there is a trend,
Parametric and non-parametric tests are applied to the metrological data as the
precipitation and temperature, in addition, the drought indices are calculated for the
different time windows. and subsequently calculating drought events in the main
basins impacting on the downstream flow.
Then river discharge data are analyzed using different hydraulic indices at key stations
in the downstream country and measuring the alterations occurring in the flow. The
degree of alteration is a function of the number of civil engineering projects being in
operation and classified by time windows; pre-alteration is between 1900 and 1925,
while the alteration period is between 1933 and 2012. The alteration period was
classified into three periods based on the degree of alteration.
The research includes analyzing the records of river discharge reaching Egypt for 112
years. The total record of discharge (112 years) will be divided to time-windows based
on the degree of interventions, statistical analysis is applied to the discharge of each
time window, the alteration in discharge is compared between the different time windows. Finally, the investigation of the water usage in the upstream countries
through existing structures and consumptive use of water.
The different time windows in the study was between 1900 and 1925, 1933 and 1963,
1964 and 1999, and between 2000 and 2012. It was found that the highest period with
the discharge alteration was the last period, and this period had the strongest drought
events then came the period 1964—1999.
The precipitation patterns had a decrease in the last two periods (1964—1999) and
(2000—2012). The high alteration and strong drought events affected the river
discharge in these two periods compared to the original period between 1900 and 1925.
The results showed that there was no significant change in trends of the precipitation
in the Nile basin and the major flow contributor sub-basins. There was a noticeable
decline in trend at the two key river discharge stations (Dongola and Tamaniat
stations).
The increased drought events affected the precipitation pattern in this period. The
influence of the human induced factors and how they can control the river discharge
increased with the degree of intervention, especially in periods with low precipitation
and river flow.
The findings revealed that there are changes in the river flow regime caused by both
changes in the rainfall pattern in addition to the regulation in the upstream countries.
There is a direct relationship between the interventions in the upstream countries and
changes in the flow regime especially when coupled with drought events. By
increasing the water usage upstream, there is an increase in the alteration of the flow downstream. The years between 2000 and 2012 were linked to the highest alterations
between the modified years.
The proposed framework is a step forward in filling the gap in knowledge by analyzing
how the river discharge react climate variability coupled with human intervention in
large river transboundary basins.
The water resources future strategic plan could be built based on the river discharge
situation and how the river discharge is proportional to the variability in climate and
human intervention.

Citation

Ahmed, Y. Water resources management & hydroclimatic data analysis in transboundary river basins under the influence of climate variability & water abstraction : Nile river basin. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: Oct 7, 2020
• Publicly Available Date: Oct 7, 2020
• Award Date: Sep 30, 2020