Showing 3 results for Mpsiac
Sayed-Farhad Mousavi, Ahmad Mohammad-Zadeh, Ahmad Jalalian, Hossein Samadi-Boroujeni,
Volume 1, Issue 2 (10-1997)
Abstract
One of the most vital problems in the storage and utilization of surface waters for drinking, flood control, hydropower, and agricultural purposes is that of sedimentation in reservoirs and subsequent decline of dam lifetime. The useful lifetime of a dam is defined as the time necessary for approximately 80% of the volume of its initial capacity to be filled by sediments washed in by water. It is a function of the volume of the incoming sediments, specific weight of sediments, and reservoir trap efficiency. Trap efficiency depends on sediment characteristics, life, shape, and rule curves of the reservoir as well as on the capacity-inflow ratio. It is the purpose of the present study to calculate sediment trap efficiency of small dams and also to determine the relationship(s) among the effective parameters in the Chaharmahal and Bakhtiary region. For our purposes, 14 small earth dams (with heights of less than 15 m and capacities of about 1 MCM) were selected around Shahrekord and Borougen. Since no data were available on the erosion and sedimentation for these dams, the MPSIAC empirical model was used to estimate the incoming sediment to the dams' reservoirs. The model considers nine factors effective on erosion and sediment production in each watershed. These factors were analyzed for the watershed of each dam under study and the annual sediment yield was calculated. The amount of sediments retained in the reservoirs as a result of the working life of the dams was estimated by reservoir surveying. The trap efficiency was calculated for all the reservoirs under study. The results obtained revealed that the trap efficiencies for these small dams ranged from 10.4 to 68.9%. New curves were developed and suggested for the trap efficiency of small dams based on these results.
S. Rastgoo, B. Ghahraman, H. Sanei Nejad, K. Davary, S. R. Khodashenas,
Volume 10, Issue 1 (4-2006)
Abstract
This research is aimed to predict erosion and sedimentation of Tang-e-Kenesht basin in Kermanshah province using MPSIAC and EPM models in GIS software. This basin has about 14348 hectare area. This region has various vegetation, geology and soil texture and land use types. The basin has divided into 9 sub-basins and its maximum and minimum elevations are 3300 and 1400 m, respectively. Needed data were collected in part through published reports, while the remainings were derived by field survey. Necessary maps in MPSIAC and EPM models were prepared in Autocad-2000 medium and were transported to Arc-Info, after some revisions to them. After constructing topologies for all polygons, we entered all layers weights in Arc-View software. Combinations of all layers were managed thereafter. Nine layers for MPSIAC model and three layers for EPM model were combined to result the final layer of erosion and sedimentation. Basin erosion was calculated as 1002.7 and 1739.2 m3/Km2 by MPSIAC and EPM models, respectively. The result for basin sediment was 521.7 and 307.8 m3/Km2, respectively. Thereafter, medium and high erosion classes were found for the two models under study, respectively. Due to not fully compatible tables for EPM model and its subjective nature, one can conclude that MPSIAC model may have better performance.
H. Hosseinkhani, E. Ghanbari Adivi, R. Fatahi Nafchi, A. Raeisi,
Volume 29, Issue 4 (12-2025)
Abstract
Soil erosion and sediment transport are among the key challenges in the management of water and soil resources in Iran. In this study, the Modified PSIAC (MPSIAC) empirical model was applied to estimate sediment yield and evaluate the erosion status in the Plasjan watershed. The model is based on the assessment of nine influencing factors, including geological characteristics, soil properties, climatic conditions, runoff, land slope, vegetation cover, land use, surface erosion, and channel erosion. By assigning scores to each factor and integrating the spatial layers, the sediment yield intensity of each sub-watershed was quantified both qualitatively and quantitatively. The required base data were prepared and analyzed using the Geographic Information System (GIS). Subsequently, the final erosion index for each sub-watershed was calculated, and erosion hazard classes were determined according to the model’s standard tables. The total annual sediment production in the watershed was estimated at 803,301 tons, and the Sediment Delivery Ratio (SDR) was calculated as 14.48%, indicating considerable sediment deposition along the transport paths. The results showed that most sub-watersheds fall within the “moderate” erosion class, while insufficient vegetation cover, steep slopes, and land-use changes were identified as the main contributing factors to increased sediment yield. Based on these findings, identifying critical areas, implementing erosion control measures, and utilizing remote sensing and sediment monitoring technologies are strongly recommended. This study provides a scientific basis for improving watershed management and mitigating erosion-related risks in similar basins.
