Int. J. Environ. Sci. Tech., 6 (2), 315-324, Spring 2009
ISSN: 1735-1472
© IRSEN, CEERS, IAU
Received 20 July 2008; revised 26 November 2008; accepted 18 February 2009; available online 1 March 2009
*Corresponding Author Email: eimam@aucegypt.edu
Tel.: +202 3336 1888
Impact of control structures on assimilative capacity of rivers and fish habitat
*E. H. Imam; S. A. El Baradei
Construction Engineering Department, American University, Cairo, Egypt
ABSTRACT: This research studies the impact of water level control structures on self-assimilative capacity of rivers and on fish habitat. Constructing a water level control structure in a river reach will alter its hydraulics as well as its water quality, thermal regime and fish …ver más…

Eid studied this impact but,
E. H. Imam; S. A. El Baradei
316
the simulated water temperature was assumed to be consistent with a linear relation and the lag time between water and air temperature wasn’t considered.
This paper studies the impact of water level control structures on the self-assimilative capacity of rivers and assesses possible changes in the ecosystem and fish habitat. For this purpose, water quality indicators were developed in order to express this impact in a quantifiable manner. This study was carried out in
2005 on the Esna barrage, in Egypt.
MATERIALS AND METHODS
The impact of constructing a water level control structure across a river is numerically modeled. The model consists of two main sub-models; a hydraulic sub-model and a water quality sub-model as described in Fig. 1. The water quality sub-model consists of a dissolved oxygen simulator along with its components such as biological oxygen demand, reaeration, photosynthesis and respiration. Two additional sub-models were developed: The temperature sub-model and the fish habitat submodel.
Hydraulic sub-model
The hydraulic sub-model simulates backwater curves, velocities and areas for a controlled river reach of