Water on the earth is in motion through the hydrological cycle. The utilisation of water for most of the users i.e. human, animal or plant involves movement of water. The dynamic and renewable nature of the water resources and the recurrent need for its utilisation requires that water resources are measured in terms of its flow rates. Thus water resources have two facets. The dynamic resource, measured as flow is more relevant for most of developmental needs. The static or fixed nature of the reserve, involving the quantity of water, the length of area of the water bodies is also relevant for some activities like pisciculture, navigation etc.