He proposed that horizontal creep has less head and is less effective in reducing uplift than vertical creep. A weightage factor of 1/3 is proposed for horizontal creep and 1.0 for vertical creep.

Streamlines enter from upstream with some head (H), but in case of equipotential lines it is considered that in downstream side water is not present. So, even though energy dissipation takes place re will some residual head (h) will be present at certain points on streamlines. Therefore, joining se points toger forms an equipotential line.

The Hathni Kund is a concrete barrage situated on Yamuna River in Haryana and it replaced Tajewala Barrage in 1999 which is out of service now. It diverts water into Western and Eastern Yamuna Canals.

The hydraulic design of a weir involves determining section of weir, details of upstream cutoff, crest, glacis, floor, downstream cutoff, and protection works of upstream and downstream.

According to Bligh, top width of weir wall (B?) is given by H / (G-1)^1/2 where H is head of water over weir wall at time of maximum flood and G is specific gravity of floor material. The top width generally varies from 1.5 m to 1.8 m.

For clayey soils, range is 1.6 to 3.0. For boulders, gravel, and sand it is 2.5 to 3.0 and for gravel and sand, range is 3.0 to 3.5.

The main cause of retrogression is silt carrying capacity of channel. This is explained as when a weir is constructed upstream side losses it silt carrying capacity due to formation of shoals and islands. So, refore in order to fulfil increased demand of silt carrying capacity of channel in downstream side progressive erosion takes place on downstream side leading to retrogression.

The protection works are needed both on upstream and downstream side to prevent scour hole which is travelling close to pucca floor of weir and to relieve uplift pressure. So, in order to achieve this, protection arrangement consists of an inverted filter and launching apron.

The value of upstream cutoffs has a considerable effect on decreasing uplift pressure especially from a value of 1 m to 2 m. The provision of sheet pile at U/s end and sufficient thickness of floor resists uplift pressure.

According to ory, safety against piping can be ensured by providing sufficient creep length. It is given by ?
L = CH where, C = Bligh?s coefficient and H = seepage head
OR
Hydraulic gradient (i) ? 1/C.