جستجوی مقالات مرتبط با کلیدواژه « rainfall simulator » در نشریات گروه « جنگلداری »

Different parts of forest roads and uphill are usually the main sources of surface runoff, sediment, water resources pollution in forest streams and soil loss. Today, soil erosion and its consequences is a global matter of concern. This study was conducted in Kohmiyan forest near-Azadshahr in order to assess the effect of forest road uphill gradient in controlling the runoff production and soil loss by a rainfall simulator. Treatments include four levels of gradients (>20%, 20-40%, 40-60% and 60-80%). Other parameters such as soil moisture content, resistance to penetration, vegetation cover and precipitation were considered constant. Then, the amount of runoff and soil loss in each level were collected at an intensity of 80 mm/h with 15 min duration and sampled at three minute intervals. The results indicated that the average amount of total runoff in level 1 (gradient >20) to level 4 (60-80%) were 5.97, 10.14, 14.27 and 18.60, respectively. Sediment concentration were 4.15, 5.87, 7.84 and 10.68 g/l-1; runoff coefficient were 12.01, 20.25, 28.51 and 37.20 percent and total soil loss were 21.65, 54.67, 108.13 and 191.51 gr, respectively for each one square meter. The results of ANOVA showed there is significant difference between the amount of runoff and soil loss due to road gradient. The results of Duncan test also indicated that with increasing uphill gradient, the amount of runoff and sediment increased significantly.

Roads provide access to forest resources for properly management of timber production, transportation, forest protection and ecotourism. Forest road networks are usually the main source of sediment in forest watersheds. Globally, soil erosion is one of the most important environmental problems which is threaten soil and water resources. Therefore, poor planning and construction causes pollution of forest streams and damage to aquatic life. Road Gradient is one of the main factors of road construction standards. Determining the relation between road gradient and amount of sediment production can be used efficiency by forest manager to choose proper gradient for new roads. This study was conducted in Kohmiyan Forest-Gorgan, and three different segments with 3% 6%, 6%-9% and 9%-12% gradient were selected on road network. investigation Using rainfall simulation the effect of road gradient on amount runoff production and sediment was assessed. In three segments, other parameter such as: roadbed, amount traffic and precipitation are similar. The results indicated that the average amount of runoff produced in segment 1 (gradient 3%- 6%), segment 2 (6%- 9%) and segment 3 (9%-12%) were 21.00, 35.60 and 51.10 litter respectively for each one square meter and average amount of sediment were 3.54, 8.11 and 12.11 g/l. The results of analysis of variance showed significant differences between amount of runoff and sediment due to road gradient. The results of Tukey test showed significant differences among mean runoff and sediment of three segments and increasing with increased road gradient. So keeping the road gradient in standard range is an important factor for controlling runoff and sediment.