engleski

Hydraulic Aspects of the Vegetation Growth in the Canals

Surface drainage as an engineering system must sustain designed dimensions during long time period and fulfill its function. It is based on hydrologic and hydraulic calculation and on the hydropedological characteristics of agricultural land that is being drained. Sustaining of the designed dimensions of the canal and functioning of the system at different flow rates require regular maintenance. Effect of irregular maintenance of canals is overgrowing which reduces the flow rate. Vegetation in canals increases hydraulic roughness, flow resistance respectively, and influences the changing of velocity and water depth. The magnitude of this effect depends on the type of soil, physical properties of the canal, but also on the amount and type of vegetation (woody or herbaceous vegetation). Because of irregular and insufficient maintenance, cross section of canal will be changed and slopes will become overgrown with perennial woody vegetation. However, the vegetation in the drainage and irrigation canals has many positive impacts. Vegetation roots reinforce the canal banks and bottom and reduce erosion . Plants increase flow resistance and thus reduce the flow velocity which affects the geomorphological stability. Vegetation also reduces sediment transport and backfilling the bottom of the canals. The positive effect of vegetation in surface drainage systems is absorption of nutrients coming from agricultural land. The aim of this paper is to show the impact of vegetation in drainage and irrigation canals through various quantitative and qualitative, both positive and negative aspects. Emphasis is placed on the complexity of the flow calculations, taking into account any herbaceous or woody vegetation.

surface drainage system; roughness; maintenance; water quality

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