Water allowance of canal command is one of the key factors in improving the crop productivity and needs to be rationalized. The water allowance for early canal system was designed on average cropping intensity and area to be irrigated. Water allowances are different for different canal commands and these affects command area differently. For command areas where design water allowances are high than the crop water requirements it causing water logging, while in areas where design water allowances are low, un- satisfactions to crop water requirements has been observed that resulted in low productions. A Crop Water Allocation Model has been developed for optimal water allowance for a given canal commands and presented in this technical book. Application of CWAM was made to Kasur minor and suggested its adoptability for further testing under changing environment.The authors appreciate the efforts of Barthlemy Chaton and his team in providing guidance for book finalization and highly acknowledge publishing of it by VDM Publishing House Ltd. for scientific knowledge sharing globally.