ABSTRACT
Qarun Lake constitutes the most important and striking feature of El Fayoum depression. It constitutes the remnants of the ancient fresh Moris Lake. It is now forming a promising area for new development projects such as salt production, fisheries and tourism. Unfortunately, the continuous rise of the Lake water level and salinity content not only threaten the old agriculture activities but also the new developed ones. A water budget model was applied through the year 2005 to estimate the quantity of the excess water that causes these problems. Accordingly, the inflow water is estimated as 586.42 million m[3] and outflow water amounts to 436.22 million m[3], so the storage content equals 150.33 million m[3]. This amount of water is being stored in the lake every year and is responsible for the continuous rising of the lake level. Reviewing the actual water quantity stored in the lake through the same interval reveals that an amount of water equals 175.88 million m[3]. This means that the quantity of water actually stored in the lake exceeds the quantity of water that enters the lake through precipitation, groundwater seepage and drainage water [inflow water] by 25.55 million m[3]. This addational quantity recharges the lake besides the previously mentioned sources. The source of this water may attribute to the upward leakage from the deep aquifers and/or seepage from Wadi El Rayan lakes along deep fissures and fractures. The higher bottom salinity of the lake's water than the surface salinity enhances this result. The salinity difference ranges from 0.01 g/l to 2 g/l with an average value amounts to 0.77 g/l. In a trial to predict the behavior of the lake surface in the next ten years, the lake level is simulated using the MODFLOW package [version 5]. The simulation reveals that, the lake level is expected to rise from -43.09 m to -41 .5m. This means that the lake receives 223.5 million m[3] of excess water, which may damage additional areas around the lake