Ogee weir.pptx

It gives basic information about weir and little more information about ogee weir.

1. Ogee-weir 1

2. What is a weir? A weir is a concrete or masonry structure which is constructed across the open channel (such as a river) to change its water flow characteristics. Weirs are constructed as an obstruction to flow of water. These are commonly used to measure the volumetric rate of water flow, prevent flooding and make rivers navigable. 2

3. 3 Types of Weirs : 1. Types of Weirs based on Shape of the Opening 2. Types of Weirs based on Shape of the Crest Sharp-crested weir Broad- crested weir Narrow-crested weir Ogee-shaped weir Trapezoidal weir Triangular weir Rectangular weir

4. Generally ogee shaped weirs are provided for the spillway of a storage dam. The crest of the ogee weir slightly rises and falls into a parabolic form. Flow over ogee weir is also similar to flow over rectangular weir.           Ogee-shaped weir: 4

5. Advantages of Weirs Can measure a diverse variety of flows correctly. It is compact and adjustable. Easy to build. Has more precise discharge rating than flumes . and orifices . 5

6. Disadvantages of Weir Relatively large head required, especially in free-flow conditions. The upstream pool must be kept clear of sediment and kept free of weeds and litter . Otherwise, the accuracy of the calculation would be impaired. 6

7. Thank you 7