scholarly journals Evaluating the Trend of Changes in Bed Sediments Gradation over the Sistan River

2021 ◽  
Vol 11 ◽  
pp. 08-14
Author(s):  
Mahdi Motallebian ◽  
Farzad Hassanpour ◽  
Hadi Kamell
Keyword(s):  
Statistical Parameters ◽  
Uniformity Coefficient ◽  
River Bed ◽  
Distance Weighting ◽  
Study Interval ◽  
Arc Gis ◽  
Standard Classification ◽  
Bed Material ◽  
Gis Software ◽  
Inverse Distance

Sediment movement in rivers is one of the most important indicators to evaluate the health of an ecosystem. Bed load different specification such as shape, dimensions and other statistical parameters of this sediment reflect the hydraulic and hydrological conditions governing them, directly. To investigate the changes of particle aggregation of Sistan river bed, four sediment samples were collected from the Sistan river. After aggregation of sediments in the laboratory, sediment diameter (D50) and uniformity coefficient (Cu) was calculated, and using inverse distance weighting (IDW) method, the mentioned parameters for the Sistan river from Jarikeh up to the AfzalAbad plugs place were interpolated and parameters using ARC-GIS software was zoning along the river. Results showed that Sistan river bed material is sand and silt, 3 km to the beginning and at end of the study interval based on the English standard classification it is silty texture and the rest of bed is sandy texture. 11 kilometers beginning and the end of the river also from 20 +721 kilometer up to about 12 kilometers has also a good aggregation. The entire river except for the middle section of river from the 13 +244 km to extent of 4 km river bed has non-uniform soil.

scholarly journals A Multimethod Analysis for Average Annual Precipitation Mapping in the Khorasan Razavi Province (Northeastern Iran)

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 592
Author(s):  
Mehdi Aalijahan ◽  
Azra Khosravichenar
Keyword(s):  
Regional Planning ◽  
Interpolation Method ◽  
Absolute Error ◽  
Rain Gauge ◽  
Annual Precipitation ◽  
Coefficient Of Determination ◽  
Distance Weighting ◽  
Average Annual Precipitation ◽  
Inverse Distance

The spatial distribution of precipitation is one of the most important climatic variables used in geographic and environmental studies. However, when there is a lack of full coverage of meteorological stations, precipitation estimations are necessary to interpolate precipitation for larger areas. The purpose of this research was to find the best interpolation method for precipitation mapping in the partly densely populated Khorasan Razavi province of northeastern Iran. To achieve this, we compared five methods by applying average precipitation data from 97 rain gauge stations in that province for a period of 20 years (1994–2014): Inverse Distance Weighting, Radial Basis Functions (Completely Regularized Spline, Spline with Tension, Multiquadric, Inverse Multiquadric, Thin Plate Spline), Kriging (Simple, Ordinary, Universal), Co-Kriging (Simple, Ordinary, Universal) with an auxiliary elevation parameter, and non-linear Regression. Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and the Coefficient of Determination (R2) were used to determine the best-performing method of precipitation interpolation. Our study shows that Ordinary Co-Kriging with an auxiliary elevation parameter was the best method for determining the distribution of annual precipitation for this region, showing the highest coefficient of determination of 0.46% between estimated and observed values. Therefore, the application of this method of precipitation mapping would form a mandatory base for regional planning and policy making in the arid to semi-arid Khorasan Razavi province during the future.

scholarly journals Spatial Distribution of Soil Nutrients in Farmland in a Hilly Region of the Pearl River Delta in China Based on Geostatistics and the Inverse Distance Weighting Method

Agriculture ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 50
Author(s):  
Rumi Wang ◽  
Runyan Zou ◽  
Jianmei Liu ◽  
Luo Liu ◽  
Yueming Hu
Keyword(s):  
Spatial Distribution ◽  
Pearl River Delta ◽  
Pearl River ◽  
Weighting Method ◽  
Farmland Protection ◽  
The Pearl River Delta ◽  
Hilly Region ◽  
Distance Weighting ◽  
The Pearl River ◽  
Inverse Distance

Soil nutrients are essential factors that reflect farmland quality. Nitrogen, phosphorus, and potassium are essential elements for plants, while silicon is considered a “quasi-essential” element. This study investigated the spatial distribution of plant nutrients in soil in a hilly region of the Pearl River Delta in China. A total of 201 soil samples were collected from farmland topsoil (0–20 cm) for the analysis of total nitrogen (TN), available phosphorus (AP), available potassium (AK), and available silicon (ASi). The coefficients of variation ranged from 47.88% to 76.91%. The NSRs of TN, AP, AK, and ASi were 0.15, 0. 07, 0.12, and 0.13, respectively. The NSRs varied from 0.02 to 0.20. All variables exhibited weak spatial dependence (R2 < 0.5), except for TN (R2 = 0.701). After comparing the prediction accuracy of the different methods, we used the inverse distance weighting method to analyze the spatial distribution of plant nutrients in soil. The uniform spatial distribution of AK, TN overall showed a trend of increasing from northeast to southwest, and the overall spatial distribution of AP and ASi showed that the northeast was higher than the southwest. This study provides support for the delimitation of basic farmland protection areas, the formulation of land use spatial planning, and the formulation of accurate farmland protection policies.

scholarly journals Comparison of Different Interpolation Methods for Prediction of Soil Salinity in Arid Irrigation Region in Northern China

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1535
Author(s):  
Tonggang Fu ◽  
Hui Gao ◽  
Jintong Liu
Keyword(s):  
Soil Salinity ◽  
Subsurface Layer ◽  
Salt Content ◽  
Spatial Prediction ◽  
Northern China ◽  
Sodium Adsorption Ratio ◽  
Interpolation Methods ◽  
Distance Weighting ◽  
Total Salt Content ◽  
Inverse Distance

Numerous methods have been used in the spatial prediction of soil salinity. However, the most suitable method is still unknown in arid irrigation regions. In this paper, 78 locations were sampled in salt-affected land caused by irrigation in an arid area in northern China. The geostatistical characteristics of the soil pH, Sodium Adsorption Ratio (SAR), Total Salt Content (TSC), and Soil Organic Matter (SOM) of the surface (0–20 cm) and subsurface (20–40 cm) layers were analyzed. The abilities of the Inverse Distance Weighting (IDW), Ordinary Kriging (OK), and CoKriging (CK) interpolation methods were compared, and the Root Mean Square Error (RMSE) was used to justify the results of the methods. The results showed that the spatial distributions of the soil properties obtained using the different interpolation methods were similar. However, the surface layer exhibits more spatial heterogeneity than the subsurface layer. Based on the RSME, the nugget/sill value and range significantly affected which method was the most suitable. Lower nugget/sill values and lower ranges can be fitted using the IDW method, but higher nugget/sill values and higher ranges can be fitted using the OK method. These results provide a valuable reference for the prediction of soil salinity.

scholarly journals Evaluation of an inverse distance weighting method for patching daily and dekadal rainfall over the Free State Province, South Africa

Water SA ◽  
2016 ◽  
Vol 42 (3) ◽  
pp. 466 ◽  
Author(s):  
Mokhele Edmond Moeletsi ◽  
Zakhele Phumlani Shabalala ◽  
Gert De Nysschen ◽  
Sue Walker
Keyword(s):  
South Africa ◽  
Inverse Distance Weighting ◽  
Free State ◽  
Weighting Method ◽  
Free State Province ◽  
Distance Weighting ◽  
Inverse Distance

scholarly journals Atmospheric Deposition Effects on Agricultural Soil Acidification State — Key Study: Krupanj Municipality

2014 ◽  
Vol 40 (2) ◽  
pp. 137-148 ◽  
Author(s):  
Dragan Čakmak ◽  
Jelena Beloica ◽  
Veljko Perović ◽  
Ratko Kadović ◽  
Vesna Mrvić ◽  
...  
Keyword(s):  
Soil Acidification ◽  
Interpolation Method ◽  
Natural Processes ◽  
Target Loading ◽  
Distance Weighting ◽  
The Status ◽  
Inverse Distance ◽  
Sustainable Productivity

Abstract Acidification, as a form of soil degradation is a process that leads to permanent reduction in the quality of soil as the most important natural resource. The process of soil acidification, which in the first place implies a reduction in soil pH, can be caused by natural processes, but also considerably accelerated by the anthropogenic influence of excessive S and N emissions, uncontrolled deforestation, and intensive agricultural processes. Critical loads, i.e. the upper limit of harmful depositions (primarily of S and N) which will not cause damages to the ecosystem, were determined in Europe under the auspices of the Executive Committee of the CLRTAP in 1980. These values represent the basic indicators of ecosystem stability to the process of acidification. This paper defines the status of acidification for the period up to 2100 in relation to the long term critical and target loading of soil with S and N on the territory of Krupanj municipality by applying the VSD model. The Inverse Distance Weighting (IDW) geostatistic module was used as the interpolation method. Land management, particularly in areas susceptible to acidification, needs to be focused on well-balanced agriculture and use of crops/seedlings to achieve the optimum land use and sustainable productivity for the projected 100-year period.

scholarly journals GROUNDWATER VULNERABILITY ASSESSMENT USING DRASTIC MODEL OF UP AL-KHASSA DAM SUB-BASIN, KIRKUK, NE IRAQ

2020 ◽  
Vol 53 (2E) ◽  
pp. 12-24
Author(s):  
Madyan Al-Gburi
Keyword(s):  
Vulnerability Assessment ◽  
Groundwater Vulnerability ◽  
Aquifer Vulnerability ◽  
Drastic Model ◽  
Drastic Method ◽  
Groundwater Vulnerability Assessment ◽  
Arc Gis ◽  
Vulnerability Map ◽  
Gis Software ◽  
Program Version

Several studies and assessments have been conducted of areas exposed to pollution, especially areas that contain aquifer. The final extraction of the vulnerability map of the groundwater was constructed through the use of the DRASTIC method by applying the linear equation of the seven coefficients in the Arc GIS software program (Version 10.4). The aim of the study to assess aquifer vulnerability to pollution. Results, vulnerability map range between 75-126 (very low, low, and medium), the study area consists of very low and low vulnerability, except some areas medium vulnerability close to the center of the sub-basin in the standard vulnerability map (s) and 91-149 (very low, low, and medium) for the agriculture or pesticide vulnerability map (p), the medium vulnerability occupies a greater area the center of the sub-basin.

scholarly journals CLASSIFICATION AND MAPPING OF LAND USE AND SOME SOIL PROPERTIES IN KIRŞEHIR PROVINCE, TURKEY

2021 ◽  
Vol 8 (8) ◽  
pp. 81-93
Author(s):  
M. Cüneyt Bagdatlı ◽  
Oğuzhan Arslan
Keyword(s):  
Land Use ◽  
Soil Properties ◽  
Numerical Data ◽  
Erosion Damage ◽  
Land Type ◽  
Stony Soil ◽  
Arc Gis ◽  
Gis Software ◽  
Land Types ◽  
Digital Soil Maps

In this study, land use capabilities, land types and other soil properties of Kırşehir province were classified and analyzed. In the study, 1/25.000 scale digital soil maps obtained from the Ministry of Agriculture and Forestry (Turkey) were used. Numerical data were classified using Arc GIS 10.3.1 software, which is one of the GIS software. As a result of the research; In general, It was observed that IV. class lands were formed in the Kirsehir province IV.class lands were found to be 1658.3 km2 and it was determined that they cover 25% of the total area. It is seen that soil insufficiency is high in Kırşehir province due to slope and erosion damage. Soil insufficiency due to slope and erosion damage was found to be 3520.7 km2 and it was determined that 54% of the total area was exposed to this effect. It has been observed that the land type is generally composed of steppe, bare rocks and rubble. It was determined that the area formed by bare, rocks and debris is 1128.5 km2. It has been determined that the stony soil areas are 1094.2 km2. As a result of the study, classified map outputs related to land uses and some soil properties were obtained. It will be inevitable that this research will provide important database bases for other studies to be carried out in this region in the future.

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