Nutrient-based ecological consideration of a temporary
river catchment affected by a reservoir operation to
facilitate efficient management
Ourania A. Tzoraki, Gerald Dörflinger, Nicholas Kathijotes
and Artemis Kontou
ABSTRACT
The water quality status of the Kouris river in Cyprus was examined in order to fulfil the requirements
for ecological quality as defined by the Water Framework Directive-2000/60/EC. Nitrate
concentration (mean value) was increased in the Limnatis (2.8 mg L
À1
) tributary in comparison with
the Kryos (2.1 mg L
À1
) and Kouris (1.0 mg L
À1
) tributaries depicting the influence of anthropogenic
activities. The total maximum daily nutrients loads (TMDLs) based on the flow duration curves
approach, showed that nutrients loads exceeded threshold values (33.3–75.6% in all hydrologic
condition classes in the Kouris tributary, and 65–78% in the Limnatis tributary) especially under low
flow conditions. The TMDL graph is intended to guide the temporal schedule for chemical sampling in
all hydrologic classes. Kouris reservoir is an oligotrophic system, strongly influenced by the river’s
flash-flood character but also by the implemented management practices. Kouris river outflow,
which was reduced to one-tenth in the post dam period altered the wetland hydrologic network and
contributed to the decrease of aquifer thickness. Continuous evaluation and update of the River
Basin Management Plans will be the basis for the sustainable development of the Kouris basin.
Ourania A. Tzoraki (corresponding author)
University of Aegean, School of Environment,
Department of Marine Science,
Mytilene,
Greece
E-mail: rania.tzoraki@aegean.gr
Gerald Dörflinger
Water Development Department, Ministry of
Agriculture, Natural Resources and
Environment,
Cyprus
Nicholas Kathijotes
Department of Civil Engineering and Geomatics,
Cyprus University of Technology,
Limassol,
Cyprus
Artemis Kontou
Akzo Nobel Coatings,
Newcastle upon Tyne,
United Kingdom
Key words | Cyprus, hydrologic regime, Kouris river, measures, reservoir, temporary rivers, TMDLs,
water quality
INTRODUCTION
To date, the dynamic and sustainable aquatic and terrestrial
ecosystems are threatened by population, change of land use
and the irreversible effects of climate change (CC). Dry and
semi-arid regions at mid and low latitudes and especially
extended areas of southern Europe are suffering from
water stress and desertification. Common practices related
to lack of water include dam construction, river abstraction
and overexploitation of groundwater (Mimikou et al. ;
Krol et al. ). Despite the fact that dam construction
saves millions of cubic meters of water, the reduction of
river flow, creates severe alterations of the river ecosystems
in terms of dynamics and quality. In delta ecosystems, down-
stream of dams, a decrease in biological productivity and in
sediment transport is observed. Additionally, an increase in
the salinity of delta and agricultural areas and in general
ecosystems deterioration is particularly observed in many
parts of the Mediterranean region.
Integrated water resources management plans consider
the river basin and coastal zone as a unit, aiming to achieve
‘good water ecological quality’ according to the requirements
of the Water Framework Directive (WFD-2000/60/EC).
Therefore, the WFD provides clear instructions for the
characterization of the hydrological and chemical quality of
perennial rivers neglecting intermittent flow rivers (tempor-
ary rivers). A river is characterized as intermittent (or
temporary) if it ceases to flow every year or at least twice
every 5 years (Tzoraki et al. ). Prolonged no-flow periods
are interrupted by intense flood events which initiate trans-
port of sediment and pollution load downstream into the
coastal zone. Ecological indexes such as macroinvertebrates
and riparian vegetation metrics are affected by flow variabil-
ity (Bonada et al. ; Poff & Zimmerman ; Munné &
Prat ). In particular, nutrient fluxes are of major concern
in lakes and reservoirs because they are correlated with
847 © IWA Publishing 2014 Water Science & Technology | 69.4 | 2014
doi: 10.2166/wst.2013.783