|
|
|
Applying RS and GIS for Soil Erosion and Sediment Estimation by MPSIAC Model - A case study of Kenesht watershed in Kermanshah, Iran
H. Hesadi
Researcher of Soil Conservation and Watershed Management Research Institute, Kermanshah province, Iran.
Email: hhesadi@yahoo.com
Kh. Jalili
Researcher of Academic Center for Education, Cultural and Research, Kermanshah Province, Iran.
Email: khaliljalili@yahoo.com
M Hadidi
Researcher of Academic Center for Education, Cultural and research, Kermanshah Province, Iran.
Email: hadidi@acecr.ac.ir
Abstract
Soil losses in the world is one of main causes of fertility decreasing , sedimentation in canals and irrigation canals and rivers, decreasing of storage capacity in the dams ,increasing of floods frequency , environmental pollution and it prevents from stable development . Deficit in erosion data for quantity estimation in watersheds especially in watersheds with no measurement has caused that scientists and researchers to have a tendency toward to use of experimental methods for erosion and sediment studies. MPSIAC is one of known models that are used extensive due to suitable results.
In this model using nine factors that include surface geology, soil characteristics, climate parameters, run off, topography data, ground cover, land use, upland erosion and canal erosion and sediment transport and then estimate erosion and sediment yield. In the last decades applying of satellite data and geographical information systems helps to the scientists for gain better results in environmental studies based on capability of RS and GIS data tools conducted a case study on Kenesht watershed using MPSIAC and compared results with traditional studies .This study showed that separating homogeneous units is done better than traditional method, meanwhile the consumed time and costs new methods are very low. Results showed specific sediment yield range in homogeneous and hydrologic units is 1.92 to 26.09 and 3.45 to 5.37 ton/ ha/ year respectively. The amount of total sediment yield in homogeneous and hydrologic units in Kenesht watershed is 74305.47 and 66076.8 ton/year respectively; that show significant difference between traditional and new methods estimation.
Introduction
Soil erosion as "soil cancer" is a complex process and its multiple obvious and hidden social and environmental impacts are an increasing threat for the human existence (Ownegh, 2003). This phenomenon with decreased soil fertility cause the destruction of natural ecosystems like pastures, jungles and agricultural ecosystems (Bayramin , 2003) and Soil erosion rate is a key index for the assessment of land management strategies and sustainability of development programs of the countries (Ownegh, 2003).
Stable development of soil and water resources and effective life cycle, continuous productivity and premium of projects need correct estimation of elements and effective factors on soil erosion and the sedimentation of the regions (Barkhordari and Zaremehrjerdi, 2006). So complete knowledge and awareness of this phenomenon is vital. Expansion and presentation of qualitative relationship between the factors which are important for soil erosion is an essential need in soil erosion control (Nikkami, 2003).
Controlling and estimation of erosion intensify and sedimentation amount is essential for watershed management projects and determining the methods for fighting against this phenomenon in order to perform soil conservation programs and exact designing of erosion and sedimentation control structures is essential (Barkhordari and Zaremehrjerdi, 2005, Hadiane amri et al., 2006).
Obvious lack or shortage of statistics and information about soil erosion and sedimentation in many watershed areas because of lack of sediment measuring stations and high cost of such stations, using suitable experimental methods for the estimation of soil erosion and sedimentation reduction is very important (Refahi, 2004, Hadiane amri et al., 2006).
MPSIAC model is an experimental model for sediment estimation which has the ability to survey erosion and sedimentation in a qualitative and quantitative manner (Ahmadi, 1999).This model has been adapted for many watershed regions of storage dams in the Iran(Refahi, 2004) and is widely used in executive and research departments for erosion and sediment estimation(Nikkami,2003). Being a ware about the active nature of erosion and the calculation and drawings to reduce this process gives important information to specialists of soil preservation, designing dams, tankers, canals and resources management and damage estimation. Using this method in GIS is very easy so in most researches and studies this model is used to estimate erosion and sedimentation.
|
|
|