الفهرس 
LITERATURE REVIEWOnly 14 pages are availabe for public view
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Abstract
The study of the natural grassed canal is an important aspect of hydraulic engineering. Vegetation in a canal affects the flow discharge, roughness, flow depths, specific energies, and state of flow. They may be natural or artificial, flexible or rigid, submerged, or imerged. The majority of this research work was established based on terrestrial plants and plastic molds as laboratory factors, whereas there are only few studies done with natural aquatic vegetation. Hence, in the present study, the most common kinds of natural vegetation are Polygonum Serrulatum and Eichhornia Crassipes sitting at 500 m from the
canal beginning. The analysis of the grassed canal is aided by the use of two equations. The first one is the Manning’s equation which used to study the effect of vegetation on the roughness coefficient. The second is a specific energy equation which equals the sum of flow depth and velocity head terms to study the losses in the grassed canal. In the present work, fieldworks were carried out on Ganabia 9B in the southeast of ElMahalla El Kubra, El-Garbia, Egypt. The effect of natural vegetation canal sections is
highlighted. The different average heights of natural vegetation in the grassed canal were 28, 46, 67, 90, and 115 cm. Velocities at different sections were measured using the Flow
Tracker device. The velocities and water depths were measured exactly every 100 m in the longitudinal direction, every 0.5 m in the cross-sectional direction, and every 5 cm in
the vertical direction. Rectangular weir was established at 700 m from the beginning of the canal to obtain steady flow with constant discharge and water surface along the canal.
The field results of the present study are presented in the form of tables, curves, and statistical equations. The characteristics of flow and comparison between un-grassed and grassed canal for discharge values varied between 11.9 and 129.25 L/s are presented. A
comparison of the present study with the previous works is presented. Three programs, namely, Statistical Package for the Social Sciences (SPSS), Artificial Neural Network (ANN), and Gene Expression Programming (GEP), were employed to create empirical formulas involving the Manning’s coefficient and relative specific energy through the grassed and un-grassed canals. A comparison between these programs is presented.
It is found that analysis of the hydraulic parameters indicated the existence of strong correlations between Manning’s coefficient and the Froude number. For a higher value of
the Froude number, the Manning’s coefficient gradually closes to a constant value. The values of Manning’s coefficient in the case of studying the grassed canal ranged from
0.014 to 0.4302 and ranged from 0.0123 to 0.081 in the case of an un-grassed canal. The Manning’s coefficient in partially submerged vegetation was higher than in submerged vegetation. The mean values of Manning’s coefficient increased with increasing value of grass height.
Energy and momentum coefficients were calculated for all different sections by using isovelse. The values of energy and momentum coefficients for an un-grassed canal were higher than the grassed canal. The energy coefficient in the grassed canal was higher than in the un-grassed canal, at a ratio ranging from 0.54% to 4.37%. The value of relative specific energy in the case of an un-grassed canal was higher than the grassed canal and increased with increasing value of submergence ratio. To verify the results, the data obtained in the present work were compared to those collected from previous studies, where a sound agreement was confirmed. Based on the statistical analysis conducted by SPSS, ANN, and GEP, the GEP program presents the best results.