Uncertainties in Water Resources System and Risk Analysis Method

One of the key problems in water resources system research today is how to quantify uncertainty, which is inherent in every water resources system. Uncertainties are the origin of risk in hydrology and water resources. In this paper, the types of uncertainties in water resources system are comprehensively concluded, such as random, fuzzy, grey and unascertainty, and the concept of uncertain system of water resources is puts forward. From the points of mathematical proceeding of uncertainty factors, the risk analysis model based on probability theory (related to the field of random) is introduced, and new risk analysis models based on fuzzy subordinative degree (related to the field of fuzzy), grey number (related to the field of grey) and unascertained mathematics (related to the field of unascertainty) are put forward. It lay a foundation for risk planning and management of water resources.