Page - 1268 - in Book of Full Papers - Symposium Hydro Engineering

rusting. The lifetime of such structures, depend on many variables in design, construction, operation and maintenance procedures. Some experts estimate the lifetime of these structures in the range of 100 – 200 years. Anyway, these structures must be rehabilitated or replaced after a defined period of time. The oldest functioning regulators in Egypt are Dairout Group of Regulators that were built in 1872. Table 1 Number of main hydraulic structures according to year of construction and location on the waterway Nombre de structures hydrauliques principales selon l'année de construction et l'emplacement sur la voie navigable Before 1900 1900 - 1920 1920 - 1945 1945 - 1970 After 1970 Sub - total Nile Barrage 0 2 2 1 3 8 Big Head Regulator (HR) 2 3 4 2 5 16 Big Intermediate Regulator (IR) 5 0 4 6 13 28 Smaller HR/ IR 7 4 27 49 14 101 Sub-total 14 9 37 58 35 153 2. PROBLEM DEFINITION Having in mind the water scarcity challenges that Egypt face and the vital need to adopt all required measures that improve water allocation and use efficiencies, RGBS initiated a replacement programme to many of these structures several years ago. This programme is in parallel with a continuous maintenance and rehabilitation programme. The rehabilitation programme was generally adopted yearly by reporting urgent defects in certain structures and allocating the required budget for the necessary remedy actions. Longer planning was not possible for more than a 5 year ahead plan. The (RGBS) authority was in need to have longer ahead plans up to the year 2050. In order to decide action for a certain structure, remedy action or rehabilitation, the optimisation between urgency of remedy action and the importance of the structure was always a debate that could only be settled by own experience of the decision maker. Capacities and state-of-the-art tools to support informed decisions were not available. Moreover, unavailability of such tools could lead to wrong decisions 1268