Low (web) Quality - BALTEX

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Climate change impacts on the water quality: A case study of the Rosetta
Branch in the Nile Delta, Egypt
Alaa El-Sadek 1
1 Researcher, Drainage Research Institute, National Water Research Center, Delta Barrage, P.O.Box 13621/5, Cairo, Egypt.
alaa_elsadek@yahoo.com
A physico-chemical water quality model has been developed
for the Rosetta Branch in the Nile Delta, making use of the
MIKE11 river modelling software of DHI Water &
Environment (DHI, 2002). The physico-chemical water
quality (WQ) module of MIKE11 was linked with a detailed
full hydrodynamic (HD) model developed for the same
Rosetta Branch, and also implemented in the MIKE11
modelling system. The WQ model aims to describe and
predict concentrations of dissolved oxygen (DO),
biochemical oxygen demand (BOD) and nitrogen in the
form of ammonia (NH 4 -N) and nitrate (NO 3 -N), taking into
consideration advection, dispersion and the most important
biological, chemical and physical processes. All significant
pollution sources along the Rosetta Branch were considered.
The objective of this research is to study the effect of the
climate change in terms of temperature on the water quality
statues in Rosetta branch in the Nile Delta of Egypt. The
results of this research indicated that, climate change is
likely to increase the stress on rivers already under pressure
from salinity, over-allocation and declining water quality.
Higher water temperatures and reduced stream flows will
tend to adversely affect water quality - water temperature,
oxygenation, nutrient and pollution loads, salinity and other
water chemistry - affecting habitat values for aquatic and
riparian species and affecting human uses.
Changes in water quality could have implications for all
types of uses. For example, higher temperatures and changes
in water supply and quality could affect recreational use of
rivers or productivity of freshwater fisheries. Finally, the
research concluded that, with respect to water quality, most
climate change impacts can be attributed to changes in either
discharge or in water temperature. To a minor degree
climate change may also affect the levels of direct
atmospheric input of nutrients and other elements to the
surface waters. The discharge controls dilution and
residence times. When temperature increases, oxygen
diffusion to water decreases and biological activity is
enhanced. The development of water quality will depend
essentially on the future evolution of human activities. The
effectiveness of wastewater treatment, agricultural practices,
water withdrawals and many other factors will play an
important role.