Effective irrigation and drainage systems are essential if growing demands for water resources are to be met. For the use of water for irrigation to be improved we must understand current levels of performance. This book draws together the growing body of knowledge on irrigation and drainage performance assessment that has been gained over the last twenty years. It provides guidelines for practitioners to enable them to design and carry out performance assessment and implement performance-based management. Developed by a working group of the International Commission on Irrigation and Drainage (ICID) it provides a generic framework for performance assessment with guidance on the theory and practice of how to audit and assess the performance of irrigation and drainage schemes.