Seepage from Lake Burullus into the reclaimed Mansour and Zawia polder area

The Zawia and Mansour irrigation areas, formerly part of Lake Burullus, were reclaimed, drained and developed in the 1960's. Reclamation was not fully successful, however, and the agricultural land is still highly saline. Recent studies carried out on behalf of the Executive Authority for Land Improvement Projects by Euroconsult and the Study and Design Department of the Authority concluded that the groundwater tables were still too high and that the drainage should be intensified and deepened. The question remained whether, and to what extent, improved drainage would increase seepage from the lake into the polder area. The studies reported here showed that geohydrological conditions were such that no seepage of importance can be expected. Piezometer observations of vertical pressure gradients confirmed these results. Calculations showed that an increase in seepage due to improved drainage would be very small compared with the capacity of the existing drainage system.