The prediction of changes in velocity distribution and channel bed morphology is significant in open channel management and design. This paper implements experimental work to realize and quantify the effect of rigid aquatic bank weeds on vertical velocity profiles and channel bed morphology. In the experimental work, weeds were given a staggered distribution using three distances of 25, 50, and 75 mm, unilaterally and bilaterally, with Froude numbers ranging from 0.11 to 0.30, achieving 168 scenarios. Results for the tested weed cases showed that the average velocity was directly proportional to the weed density and approached the Froude number. By comparing the smooth and weeded velocities, it was found that the velocity inside the infested reach was close to the downstream velocity and exceeded the upstream velocity by about 10% and 41%, respectively. Scour depths along the centerline of the vegetated reach for the bilateral weeds were higher by 11% to 33% than those for the unilateral weeds. The maximum observed depth of the scour holes along the smooth bank was about 30% to 60% of the maximum scour depth at the middle line. Finally, to quantify the results, multiple regression analysis was performed to develop empirical equations to assist in the water management process.

Canal lining and rehabilitation aim to distribute water, reduce losses, and ensure that water reaches the ends of the canals. Recognizing the need to improve the management of the irrigation system and maintain the width of strategic adjacent roads to canals, the Western Meleg Canal in Menoufia Governorate, Egypt, was selected as a case study. A reach of 1500–3400 km faces problems that impede the implementation of the lining sector as a result of the proximity of the buildings that could not be removed on the canal banks. Two alternatives, including the contraction of the bed width or coverage of the reach from 1500 km to 3400 km on the Western Meleg Canal, were explored. A coupled one-two dimensional numerical model to replicate the water surface profile and flow velocity was implemented. The total cost of each alternative was approximately estimated. The results show that the contraction of the bed width along the considered reach has a limited effect on the levels and velocities of water along the canal, as water levels increased by 2 to 6 cm from the design levels before the contraction of the width of the bed, and the maximum velocity of the water was 0.72 m/s. In the case of covering the selected reach, the difference in water pressure through the coverage (1500:4000 km) was 74 cm, and the coverage works under free flow. The estimated cost of covering is more than four times the cost of plain concrete lining. The findings of this study may help decision-makers and could be implemented in other such canals.