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Figure 6. The present rate of relative sea-level rise as calculated in this analysis will reach ~1 m
above mean sea level (msl) by 2100 A.D., with marine water (shown in blue) having advanced land-
ward, submerging about one-third of the present Nile delta surface (after Hereher, 2010).
eustatic sea-level rise of ~3 mm/yr. A total
relative sea-level rise of 1 m or more could
well occur at this delta’s low margin, but
not by eustatic rise alone, which accounts
for only ~26% to 45% of measured total
estimated relative sea-level rise (~6.7 mm/yr
to ~11.4 mm/yr) between the delta’s NW
and NE coastal margin. Total relative sea-
level rise by year 2100 could be further
increased locally by neotectonic lowering
as has occurred sporadically and affected
the delta’s margin in the recent past.
Additional repercussions are envisioned
from the effects of a continued decrease of
Nile sediment now reaching the coast,
resulting from increased anthropogenic
entrapment by new up-river dams and
other structures, plus increased rates of
eustatic rise in sea level due to higher rates tional accords with regard to the Nile’s
of polar ice melt that, in years ahead, may
possibly accompany global warming.
Land subsidence plus eustatic sea-level
rise presently affect saline water intrusion
into the delta’s aquifer. Highly saline soils
in the northern delta become moderately
saline southward from about Kafer el-
Sheikh to the central delta (Fig. 5B). Non-
saline soils occur primarily south of Tanta,
in the central to southern delta (Kotb et al., from other countries, will be Africa’s largest
2000; Sefelnasr and Sherif, 2014). Egypt
could help ameliorate these salinization
and coastal erosion problems by construct-
ing laterally extensive, continuous, and
deeply emplaced protection structures
along the delta’s coastal perimeter. Present
ongoing quarrying of sand dunes along the
delta coast, for mineral mining and other
applications, should be avoided, because it
removes a natural protective barrier that
10 GSA Today | May 2017
backs the low-lying shoreline. Govern-
mental investment in establishing much-
needed desalination plants and drip irriga-
tion technology should be planned. Serious
indeed is decreasing agricultural produc-
tion at a time when Egypt’s population
continues to increase. Further Nile fresh
water decrease would be grave because, at
best, the river barely supplies 97% of
Egypt’s water needs, and now provides
only 660 m3, one of the world’s lowest per
capita water shares. With a population
expected to double in the next 50 years,
Egypt is projected to reach a state of seri-
ous country-wide fresh water and energy
shortage by 2025.
Additional complications include interna-
hydrology, drawn up in 1929 and amended
in 1959, that attributed most Nile water to
Egypt and Sudan without consulting
upstream states (Waterbury, 1979; Said,
1993). To address its own conditions of
drought and energy poverty, Ethiopia began
construction of its Grand Ethiopian
Renaissance Dam (GERD) in 2011, with
completion expected this year. The dam,
paid for mainly by Ethiopia, but with aid
hydroelectric power plant, producing 6000
megawatts of electricity with 16 turbines
and an estimated production of 15,000 GwH
per year. The reservoir behind the dam will
flood 1680 km2, retain a volume of ~63
Bm3, and could take 5–7 years to reach
capacity. During this period of fill, the Nile’s
fresh water flow to Egypt may be cut by
25%, with a loss of a third of the electricity
generated by the Aswan High Dam.
In addition to the GERD, Ethiopia is
proposing more dams along the Nile, and a
new series of dams is also planned in the
Sudan. With ~400 million people living in
the 10 countries across which the Nile
flows (Fig. 1), some now experiencing
severe droughts and unmet energy needs,
it is expected that a large proportion of
Nile water now directed to Egypt (~70%;
Said, 1993), will have to be reallocated
up-river (Fig. 6). Already facing a multi-
tude of economic, political, and demo-
graphic problems (Fragile States Index,
2016), in addition to hydrological and
coastal protection challenges, the interde-
pendence of the Nile Basin countries and
their reliance upon the Nile’s waters
must be resolved immediately. It is hoped
that rather than resorting to threats and
military action, some form of arbitration
by regional or global bodies be applied to
the delicate situation, especially with
regard to the three most impacted countries
along the Blue Nile: Egypt, the Sudan,
and Ethiopia.
ACKNOWLEDGMENTS
Prof. M.P. Bernasconi, University of Calabria,
Prof. P. Eager, Hood College, K. Corwin, Idaho
State University, A.N. Ellis, Adamstown, Maryland,
and two anonymous reviewers are sincerely
thanked for their valuable assistance with this
article. Messrs. L. Vianello and G. Contardi, staff
of Salini Impregilo, S.p.A., kindly shared photo-
graphs and information about the GERD dam’s
construction in Ethiopia. Research funding to the
senior author and the Mediterranean Basin
(MEDIBA) Program that led to this synthesis was
provided by the Smithsonian Institution, National
Museum of Natural History, Washington, D.C.
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