effect the sediment on discharge amount of lateral canals lining or do not lining at start joining of head regulator which at time reduce the discharge of canals with stay water level is constant or increasing because of detention of water due to sediment.
this effect on rating curve therefore must change the rating curve at all month or at before and after rising of sediment
My knowledge specific to your situation is limited to that described. But I have learned from agricultural terraces that if the gradient is too low, such as 1% gradient, the terrace will aggrade and loose capacity. If the terrace is too steep, somewhere around 2-4% gradient, the channel will degrade (entrench). Hydrologist and trainer Dave Rosgen discussed some of the irrigation canal issues that farmers and ranchers had in Colorado. When the main channel degraded to the extent that the stream was below the head gate, he discussed using Cross Vanes or J hooks to help provide needed grade control and elevate channel back to access the canal. If sediment is too great for the stream capacity, it will aggrading and possibly foul the head gate with sediment during periods of closure. An aggrading channel has too much sediment for its capacity, and are often unstable, and sometimes braided in nature. In one instance of excess sediment load, he showed is a vortex weir that was designed to remove sediment and deposit it to excavated floodplain pits. The settling of materials in the pits offered some gradation according to distance from the weir outlet pipe, so potentially gravels, and sands were somewhat sorted and might be useful for some types of construction. The excavated pits had to be regularly maintained to remove the materials so the vortex weir pipe had a clear discharge outlet or it would eventually fill with sediment. If you are familiar with stream facets, fish often use the glide after the pool to spawn, as this is often some of the cleanest water, and this may be best to tap with a head gate. But if the pools have filled, perhaps that is not an option. What sometimes works is to keep records of those sites visited, and identify those that appear to be functioning properly, then try to analyze combination of factors or conditions seem to fit the desired circumstance best. Besides technical expertise, sometimes farmers, ranchers, water keepers have some worthwhile ideas.
Dear Ali Hassan Hommadi ,
It depends on the gradient of the canal and the velocity of water. If the velocity of water is above certain level (Self cleansing) then there will be no sedimentation.