The influence of Moslem Water Law and the improved irrigation practices and techniques that accompanied the spread of Islam have had a remarkable and important impact on the Iberian peninsula, and in particular upon the irrigation system of Valencia. The system of water users association that developed within the Hispano-Muslim society has been a model used in several parts of the world and continues to be studied for its application where agriculture is essential and water limited. Pakistan applies Moslem water law principles at the local level in the allocation and distribution of water to agricultural users. At the governmental level, however, water management is a provincial matter, and in three or four provinces, the Canal and Drainage Act of 1873, introduced by the British, still is the rule of law. The interesting feature is that one of the largest and oldest irrigation systems in the world has been suffering from decay the past 50 to 80 years. Salinity is causing the loss of production on thousands of acres of land each year. The major problem is improper management at the farm level and lack of coordination among the provinces. Basically, the very principles that have helped create a very efficient and effective irrigation system in Valencia and in other Spanish districts have not had the same impact in Pakistan, perhaps due to a failure to adapt to the changing social and economic conditions of the Indus.