تأثیر تندی و جهت شیب بر روان آب سطحی و رسوب از کرت های کوچک آزمایشی درحوزة آبخیز کجور

Abstract

Abstract The proper management of a watershed depends on recognition of effective elements and investigation of their behavior in different conditions. Till date, many researches have studied the role of topographical general characteristics on hydrologic behaviors. Whereas, the changeability of hydrologic properties under different conditions, especially in Iranian watershed has been rarely taken into account. This research aimed to assess the role of slope steepness and aspect on runoff and sediment characteristics in Educational and Research Watershed of Tarbiat Modares University (Kojour) watershed located in southeastern of Nowshahr Township, Iran. Experiments were conducted by using a pressure rain simulator with an intensity of 1.6 mm min-1 and a plot in dimension of 30×30 cm in two slope ranges i.e. ≤ 25 and > 25% and eastern and western aspects. These experiments were done in three replications and in particular places on monthly basis from October 2008 to June 2009. The study was formulated in factorial and Latin square designs and the associated results were then analyzed with the help of SPSS 17 software package. Results showed that the affect of slope on runoff volume was significant (p<0.04) so that, in contrary to oft reported, the volume of runoff was lower in steeper slope. Slope steepness and aspect had also alterative significant (p<0.05) effects on sediment yield. Generally, the higher slope with coarse soil texture and less available sediment, the lower sediment yield with greater amounts in eastern slope. Keywords: Kojour Watershed, Runoff Generation, Slope Aspect, Slope Steepness, Sediment Yield