The design approach for the flood canal seems well-thought-out. Diverting water through a weir into two pathways based on rainfall intensity allows for adaptability during different flood conditions.

Below the 5-year flooding level, the water is directed along a branch line to a wetland area, serving as a means for natural purification and infiltration of the water.

For higher flood levels, the canal incorporates an overtopping mechanism at the diversion weir, diverting excess water to the river via a flood channel, for up to a 50-year return period.

Consideration of various flood levels (5-year, 30-year, and 50-year) is important for erosion control measures. Different design strategies, such as impervious concretion base for the 5-year flood, retaining walls along the slope for the 30-year flood, and pervious surface measures above that level due to low erosion risk, help meet the requirements of each flood level and velocity.

Overall, the design of the flood canal appears to account for ecological concerns, varying flood conditions, and the management of sedimentation and erosion.