Study on flow regime change due to weir construction plan in Batang Asai River, Sarolangun, Province of Jambi

The weir design process not only considers the location, dimensions, strength, and durability of the weir structure, but must also be consider the effect on the flow characteristics in the river after the weir, especially related to the flow velocity characteristic around the weir. The water level will rise and affect the flow velocity downstream of the weir. Because of the fall of water, the velocity will greatly increase and the river can erode. The weir construction on the Batang Asai River, specifically located in Sarolangun, Province of Jambi, has unique conditions that cause the velocity of water after the weir to increase. Several alternatives will be analysed as solutions to deal with changes in flow velocity. The alternatives are groundsill, riverbed normalization, and river crossing widening. It was found that the alternative of river widening showed a significant reduction in flow velocity.