Ahmad Ahmadi; Farhang Ghasriani; Anvar Sanaei; Mina Bayat
Abstract
The purpose of this study was to determine the Evaluation of different cutting intensity on some attributes of Teucrium polium and Helichrysum globiferum Gharebagh key species. In this first region and two key area of half hectare in area Gharebagh and in the first year and was grazed, and fencing. Selected ...
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The purpose of this study was to determine the Evaluation of different cutting intensity on some attributes of Teucrium polium and Helichrysum globiferum Gharebagh key species. In this first region and two key area of half hectare in area Gharebagh and in the first year and was grazed, and fencing. Selected and removed from any of 0, 25, 50, 75% and control is exercised (a basic 10 treatments). Monthly by the clipper and the area is grazing season. Effective utilization of changes in the phenological characteristics, forage and seed production, vitality, mortality and other characteristics of selected plants species were studied. Finally, the combined analysis of data from yield and vigority with a split plot design in SAS software was analyzed. Results of studies of the effects on forage production and harvest of T. polium and H. globiferum Gharebagh species studied showed that effects of different levels, different years, and their interactions on the production level is a significant percentage (p<0.01). This shows that in different years with different weather conditions of production are different. The research findings can be taken as authorized by the 50% cutting intensity for the T. polium and 25% for H. globiferum are suitable.
Saeed Golian; Ahmad Ahmadi; Narjes Salarian
Abstract
A check dam is a small dam with a simple and low cost structure and because of its specific material and simple building technology, it has a wide range of applications in flood control projects. In this research, the effects of check dams on reducing the flood peak and increasing the time of flood flow ...
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A check dam is a small dam with a simple and low cost structure and because of its specific material and simple building technology, it has a wide range of applications in flood control projects. In this research, the effects of check dams on reducing the flood peak and increasing the time of flood flow to reach to peak were investigated for Kan basin in north-west of Tehran.The hydraulic and hydrologic situation of the Kan basin was modeled using HEC-HMS software. Using hydrologic modeling the effect of building check dams on flood characteristics was studied in three scenarios of river slope change. The results showed that check dams reduced the flood peak to reduce between 0 and 0.9% in the first scenario (0.5 of the natural slope) and from 0.4% to 3.5% and 3.9% to 10.6% in the second (0.1 of the natural slope) and third (0.01 of the natural slope) scenarios, respectively. The time to peak also increased from 10 to 50 minutes. In hydraulic-hydrologic modeling, the effect of constructing check dams with no sediment in their reservoir was investigated for rainfalls of different return periods. The results revealed that with increase in rainfall return period, the effect of check dams on reducing flood characteristics will decrease. For instance, in the case of 100 check dams, the percentage reduction in peak outflow will decrease from 22.8 to 1.2 % for rainfalls of 2 and 20 years return period, respectively. In general, construction of check dams has no considerable influence on reducing constructive effects of floods. In other words, check dams should be used together with other structural and non-structural flood control methods.
