TY - JOUR T1 - Determination of Proper Size of Plots for Runoff and Sediment Estimation from Small Watersheds in Sanganeh Watershed, Razavi Khorasan Province TT - تعیین اندازه مناسب کرت‌های برآورد روان‌آب و رسوب آبخیزهای کوچک در حوزه آبخیز سنگانه، استان خراسان رضوی JF - JSTNAR JO - JSTNAR VL - 14 IS - 52 UR - http://jstnar.iut.ac.ir/article-1-1222-en.html Y1 - 2010 SP - 39 EP - 47 KW - Experimental plot KW - Iran KW - Razavi Khorasan Province KW - Runoff generation KW - Sanganeh watershed KW - Sediment yield KW - Soil erosion. N2 - Erosion plots are basically used for studying erosion processes and many related problems. However, the possibility to extend the results of experimental plots to surrounding watersheds is rarely taken into account. In the present study, an attempt was made to study on the accuracy of soil erosion plots in estimation of runoff and sediment yield from small watersheds. Towards this attempt, 12 experimental plots with length of 2, 5, 10, 15, 20 and 25 meter were installed on two north and south facing slopes in Sanganeh watershed, northeastern Razavi Khorasan Province with an area of ca. 1 ha. The performance of the plots in estimation of runoff and sediment was controlled by data collected at the main outlet associated with 12 storm events occurred during November 2006 to June 2007. The results showed that the accuracy of plot estimates on sediment and runoff improved while the plot length increased. The optimal length for estimation of sediment and runoff parameters was found to be equal to average slope length and more than 20m. M3 ER -