E. Maroufpoor, M. Parvini,
Volume 17, Issue 66 (winter 2014)
Abstract
One of the most important issues in trickle irrigation design is investigating the emitter's characteristics, the effect of factors on flow rate, and finally appropriate emitter selection. Therefore, in this study nine types of pressure compensating emitters with codes of A, B, C, D, E, F, G, M and N, made based on trickle irrigation physical model were tested and the effects of four different water temperatures (13, 23, 33 and 43°C) with different pressure ranges (between zero and 1.2 times more than the maximum pressure) on the emitters were evaluated. All experiments were carried out based on ISO 9261 standard and IRISI 6775 standard of the Institute of Standards & Industrial Research of Iran. The obtained results at all the tested temperatures, no emitter has x more than 0.2 and all emitters were pressure compensating types. The effect of temperature on the flow rates of models F, M and N was significant at 95% confidence level. Increase in temperature showed an increase in the flow rates of the above mentioned models.
S. Parvini, Z. Jafarian, A. Kavian,
Volume 22, Issue 2 (Summer 2018)
Abstract
Due to the lack of necessary equipment for measuring and recording changes in watershed runoff and flood situation after the implementation of corrective actions, using hydrologic models is considered as an efficient tool to assess the undertaken actions and simulate the behavior of the watershed before and after the implementation of these measures. The present study aimed to simulate the effects of corrective actions on runoff components using HEC- HMS hydrological models in the form of a rangeland and watershed plan in 2006 and the predicting plan of applicable operations in a region in the Meikhoran watershed, Kermanshah. For this purpose, three scenarios including the conditions before running the rangeland and watershed plan, the conditions after running the project and requirements and enforcement actions resulting from the proposed location map were considered in the spring of 2006. First, a map of the curve number (CN) changes was prepared under all three scenarios caused by the vegetation changes and by implementing HEC-HMS model, the curve number criteria, the peak discharge and flood volume were determined to assess the changes in hydrological basins and their values for all three scenarios were calculated and compared. The results showed that the HEC- HMS model for the base period (first scenario) with Nash-Sutcliffe coefficient 0/551 and the coefficient of determination 0/63 had an acceptable accuracy in predicting runoff. Nash-Sutcliffe coefficient for the second and third scenarios was 766/0 and 0/777, respectively. Also, the results showed that in the second scenario, there was an 8/85 and 7/74% decrease in the peak flows and runoff volumes, respectively, and these values for the proposed operation were estimated to be 12.84% and 6.33%, respectively. Overall, the results indicated the considerable impact of rangelands and watershed management (third scenario) on the reduction of effective runoff components, particularly flood peak, on the basis of the location model.
