48 research outputs found
Monitoring and modeling of runoff generating areas in a small agricultural watershed
No full textIt is presently well-known that more than 50% of total water quality impairment originates from non-point sources (NPS) of pollution. As an important NPS pollutant, runoff from agricultural lands contributes to water quality problems more than other non-point sources. Therefore, the identification and quantification of runoff generation areas is crucial for source water protection and nutrient management. Runoff generation is a complicated landscape process, affected by various factors in different seasons of the year. In this research, monitoring and modeling were selected as two important approaches to identify the mechanisms of runoff generation, runoff generating areas (RGAs) and its variability in time and space in a small agricultural watershed in southern Ontario. A wireless sensor network (WSN) was designed to monitor runoff generating areas in the study watershed with the ability to measure the depth of surface runoff and soil moisture over ten minutes time intervals. Eight pressure and soil moisture sensors were installed at the outlet of eight fields in the watershed. Data from eighteen natural rainfall events for the period from July 2008 to April 2009 were analyzed to study the spatial and temporal variability of runoff generation areas in the study watershed. The results showed that runoff generating areas in the watershed are highly dynamic in summer, fall and spring with differences in 100%-contribution-status persistency. The results also indicated that 15% of the watershed generates 75% of surface runoff during summer, 100% in fall and 45% during spring. In spite of the dynamic nature of RGAs, the sensitivity of different fields in the watershed in response to rainfall events remained constant, such that some specific fields responded first in all three seasons. This finding led to the introduction of a Slope/Area index for the identification of sensitive fields in the study watershed. Statistical analyses of the factors affecting RGAs indicated that the factors affecting the spatial and temporal variability of RGAs in three seasons vary; however, the soil moisture and rainfall intensity played important roles in the runoff generation mechanism and variability of contributing areas in all seasons. Based on monitored results and field observations, a hydrological model was developed to simulate runoff generating area and to classify the sensitivity of the fields to runoff generation on the basis of the modified Soil Conservation Service Curve Number approach. The model was able to identify the fields that generate runoff and classify the sensitivity of the fields in the watershed. The developed model could simulate RGAs for the summer season with higher degree of accuracy than fall. The developed model needs further improvements for simulation of runoff generating area in the spring season
Influence of structural lineaments on drainage morphometry in Qorveh-Dehgolan basin, Kurdistan, Iran
No full textIn the current study, a combination of automated lineament extraction from Landsat 8 satellite imagery and 3D interactive visual interpretation (using DEM) alongside image processing techniques (Gram-Schmidt pan-sharpening, convolution directional filter) was carried out to investigate expression and influence of tectonic activity on drainage morphometry within Qorveh-Dehgolan basin. The watersheds, derived from burned DEM using SWAT, were categorized into high and low-altitude watersheds depending on the associated relief. Analysis of spatial relationship of lineament density with drainage density and basin slope revealed that structural lineaments have a decisive control over drainage density distribution particularly at higher basin slopes of certain watersheds. These high-altitude watersheds, associated with more-resistant lithology, were also found to cover higher percentage of total lineaments compared to the lower-altitude watersheds associated with less-resistant lithology. The analysis presented significant insights into the influence of tectonic activity on drainage network in a relatively unexplored area and provided vital baseline information for future investigations.</p
Effect of conversion of rangelands to planted forests on some physical and chemical soil properties
No full textSo far it is well known that the conversion of degraded rangelands to planted forests through afforestation practices affects soil properties. Therefore, we selected one rangeland and two planted forest area to study the physical and chemical properties of soil in different land uses in Hassanabad region of Sanandaj in Kurdistan province. Physical soil characteristics such as the percentage of water content and soil bulk density were sampled in two-week intervals during 2012 to 2013 at three points in each area. In addition, a set of double rings was conducted to measure infiltration rate at three points within each area. The saturated hydraulic conductivity was computed using the experimental infiltration data. The soil samples for measuring chemical properties (e.g. pH, EC, organic carbon content, phosphorus and total nitrogen) were taken from 3 points in each area at the depth of 20 cm with six repeated measurements. The results showed that converting degraded rangelands to tree plantations has resulted in enhancing the quality of soil physical characteristics, whereas only a portion of the chemical characteristics (organic carbon content, phosphorus and total nitrogen) were positively affected
A GIS-based logistic regression model in rock-fall susceptibility mapping along a mountainous road: Salavat Abad case study, Kurdistan, Iran
No full textSurfactant assisted surface morphology and thermal properties of polythiophene composites
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Excellent approach to modeling urban expansion by fuzzy cellular automata: agent base model
No full textDrainage network extraction and morphometric analysis in an Iranian basin using integrating factor analysis and geospatial techniques
No full textThe application of multivariate statistical analysis (MSA) in analyzing drainage basin morphometry, in conjunction with seismic events (focal mechanism) and associated tectonic influences, has been discussed less in the framework of existing geomorphometric studies. Hence, in this study, an integrated approach was designed combining the geomorphometric analysis with MSA, focal mechanism and associated structural lineaments (using a remote sensing and GIS framework) to address the role of active tectonism on the drainage network characteristics in Qorveh-Dehgolan basin located in western part of Iran (Kurdistan province). Eight watersheds were delineated from burnt ASTER DEM using SWAT model and categorized into high-altitude watersheds and low-altitude watersheds. Four-sets of the drainage network were extracted from satellite imageries (Landsat 7 and 8) over a period of 17 years (2000–2017) to monitor the temporal stream network behavior. Overall, nineteen morphometric parameters were calculated (and categorized into linear, aerial, and relief aspects) exhibiting significant changes in the drainage network from 2000 to 2017 (the stream order declined from 5th to 4th order). The higher-altitude watersheds showed various anomalies in the calculated indices (indicating the potential influence of tectonic activity), while the lower altitude watersheds did not exhibit any specific anomalies. In addition, higher concentration of longer lineaments was observed in areas where the relatively resistant, fractured bedrock lithology (meta-volcanic and meta-sedimentary rocks) provided favorable conditions for origin and propagation of the lineaments. Further analysis of focal mechanism solutions (FMS, beachball diagrams) showed that the study area is primarily influenced by moderate earthquake events (3 ≤ Mw ≤ 6) and is influenced by a complex fault mechanism (primarily normal faults and strike slip faults). The morphometric parameters were further subjected to the factor analysis (principal axis factoring using Varimax rotation transformation) resulting in derivation of “factor of basin magnitude”, “factor of steepness” and “factor of texture” as three principal factors impacting the drainage network. Finally, it was concluded that “factor of steepness” played a decisive role in defining hydrology of higher-altitude watersheds (an indication of tectonic influences in these watersheds) and thereby defining the overall hydrology of the study area as well. Overall, this study highlighted the significant role of the tectonic activity associated with structural lineaments and the seismic events in defining the nature and behavior of the drainage network and certain anomalies caused in the basin hydrology under these structural controls
Analysis of Drainage Morphometry and Tectonic Activity in the Dehgolan Basin Kurdistan, Iran, Using Remote Sensing and Geographic Information System
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