Atmospheric CO2 Consumption by Chemical Weathering in the Main Tributaries of the Yellow River: Tao He, Huang Shui, and Datong He, Originating From the Northeastern Qinghai-Tibet Plateau

The Tao He, Huang Shui, and Datong He originate from the northeastern margin of the Qinghai-Tibet Plateau (QTP) and flow into the Yellow River on the Loess Plateau (LP), all with a basin area exceeding 15,000 km2, and are the three largest tributaries of the Yellow River QTP sub-basin. Water samples were collected at the river outlets, the QTP section, the transition zone between the QTP and the LP, and the LP section of each river. These water samples were used to explore CO2 consumption by chemical weathering and its control mechanisms. Runoff and physical erosion are the main factors controlling chemical weathering in the three rivers. The increase of relief ratio in the transition zone between the QTP and the LP makes the chemical weathering particularly intense in this area. The total CO2 consumption rates by chemical weathering in the Tao He and Huang Shui transition zones are 1.4 times and 1.7 times greater than in their QTP sections, and 1.7 times and 2.3 times greater than in their LP sections, respectively. In contrast, due to the high relief ratio of 8‰ in the Datong He transition zone, the residence time of the water is extremely short, and unweathered fine-grained materials are delivered downstream to continue weathering. The influence of differential lithology distribution on chemical weathering includes that the Datong He QTP section with carbonate exposure presents the most intense carbonate weathering in that basin, and the Tao He transition zone has low silicate weathering resulting from the distribution of early Permian strata. In addition, groundwater recharge most likely influenced the silicate weathering of Huang Shui significantly. The total area of the three rivers accounts for 25% of the Yellow River QTP sub-basin, while their contribution to the total CO2 consumption flux by chemical weathering approximates 36%. The silicate weathering of the northern QTP rivers is lower than the global average and significantly lower than those of the southern QTP rivers. However, carbonate weathering of the QTP rivers exhibit no north-south regional differences.

Quantitative Geomorphological Parameters Analysis for the Aynalem- Illala Streams, Tigray, Northern Ethiopia

Morphometric analysis is the measurement and mathematical analysis of the configuration of the surface, shape, and dimension of landforms. The objective of this study is to characterize the Aynalem and Illala streams using the morphometric parameter. The topographic map at a scale of 1:50,000 taken from the Ethiopian National Mapping Agency was used to characterize the linear and areal aspects. ASTER Digital Elevation Model with 10m resolution was used to characterize the relief aspect. The Arc GIS 10.4.1 was used during the morphometric analysis. The analysis result of the streams is summarized based on the linear, areal, and relief aspects. The area is characterized by a dendritic drainage pattern which is characteristics of massive hard rock terrain. The Aynalem and Illala streams are 4th and 5th order streams. Considering the number of streams in the Aynalem (75.81%) and Illala (74.66%) is composed of first-order streams that indicate a flashy flood and the mean bifurcation value of Aynalem (6.8) and Illala (4.7) shows that the Aynalem area is more structurally affected than Illala but both show less stream integration. The analysis of areal aspects such as elongation ratio, circularity ratio, and form factor has indicated that both streams are characterized as elongated streams, this implies that both streams are flowing in heterogeneous rock material, presences of structural effect, and slow runoff discharge. The other areal aspect such as drainage density, stream frequency, infiltration number, and length of overland flow all show smaller values in both streams. This implies that the streams are characterized by a relatively permeable rock material with a higher infiltration capacity. The relief aspect of the Aynalem and Illala was also analyzed using basin relief, relief ratio, ruggedness number, hypsometric curves, and Hypsometric integral. The streams are characterized by a lower relief ratio and ruggedness number which implies a relatively flat slope and lower relief. The hypsometric curves and the Hypsometric Integral of the streams indicate that the Aynalem and Illala are at the maturity stage. This shows the area is characterized by higher erosion but less affected by recent structures. Based on the morphometric parameter analysis result it is possible to conclude that the stream development is dependent on the topography and geology of the study area and both streams show similar morphometric character.

Watershed prioritization for soil erosion mapping for the Lesser Himalayan Indian basin using PCA, WSA method in conjunction with morphometric parameters and GIS-based approach

Watersheds in the subtropical Himalayan basins are highly prone to land degradation due to deforestation, landslides, intensive agriculture, population pressure, and overgrazing, in particular, where various fluvial and denudation processes occur. It is important to assess the magnitude of problem and to understand the erosion process under normal conditions, so that effective measures can be implemented. Therefore, the study selected Kalsa watershed from the Lesser Himalayan region, where soil erosion is more prominent. Regarding this issue, to identify the hotspot of soil erosion of the basin, watershed prioritization methods using advanced geographical information system and remote sensing techniques integrated with weighted sum analysis (WSA) and principal component analysis (PCA). In addition, a comparison has been made to evaluate the performance of these models. The study considered sixteen different morphometric parameters, including linear (Rho coefficient, stream frequency, drainage density, length of overland flow, drainage texture, and constant of channel maintenance); landscape (relative relief, relief ratio, basin slope, and ruggedness number); and shape (elongation ratio, form factor, circulatory ratio, and compactness coefficient). Both the method PCA and WSA indicate the same results showing high priority, meaning the outlet watersheds have high priority. The sub-watersheds in the north-eastern part have the lowest priority. The results also show that the length overland flow, relative relief, basin relief ratio and hypsometric integral are the most important indicators. The sub-watersheds prioritize high ranks, medium ranks, and low ranks out of 10 sub-watersheds covering about 45.32%, 27.78% and 26.90% area of the Kalsa River watershed, respectively. This study will help regional planners, farmers, and governments take more detailed decisions to propose efficient soil erosion control measures and conservation priorities of the watershed. The study findings have implications for sustainable land management and conservation goal targets (target 2.3 and 2.4; target 3.9; target 13.1, 13.2 and 13.3; target 15.3 and 15.4), which finally helps to achieve the United Nation’s 2030 Agenda for Sustainable Development.

Morphometric Analysis of a Drainage Basin: A Study of Ghatganga River, Bajhang District, Nepal

This study attempts to study the morphometric characteristics of the Ghatganga basin by using Geographical information system (GIS). This analysis has shown that the relation of stream order (U) and stream number (Nu) which gives a negative linear pattern that order increases with a decreasing number of stream segment of a particular order. Different morphometric parameters such as stream length (Lu), bifurcation ratio (Rb), drainage density (D), stream frequency (Fs), texture ratio (T), elongation ratio (Re), circularity ratio (Rc), form factor ratio (Rf), relief ratio (Rh) and river profile have revealed the basin has a dendritic pattern of drainage, indicating high relief and steep ground slope with less elongated young and mature landforms in which geological structures don’t have a dominant influence on the basin.

Qurain AL-Thamad Valley Hydrological Aspects Extraction Using Remote Sensing and GIS Techniques

In the arid to semi-arid lands the extracted hydrological features are essential ones, since their effect on water projects managing, agricultural projects administrating, and animals grazing, so that this research is considered to be vital research because the climate of Qurain AL-Thamad basin is arid climate and basin region inhabited by many tribes who works in agricultural and grazing fields. The illustration of hydrological features using morphometric analyses is optimum since the quantization issue of basin factors, in the past this would be difficult using classical procedures (i.e. using paper topographic maps and planmeter). Recently as in this work modern procedures has been used (i.e. satellite imagery DEM as ancillary image and Arc GIS 10.5 as geo-measuring and spatio-analyzing program). The pattern of Qurain AL-Thamad basin's drainage network shows dendritic configuration in low orders streams and parallel configuration in the high order streams. The spatial analysis using GIS environment categorize basin's shape parameters into three categories: firstly one is the linear parameters with streams divided into 1st order streams with (611.587 km) length, 2nd order streams with (384.015 km) length, 3rd order streams with (181.868 km) length, and 4th order streams with (103.674 km) length. Bifurcation ratios were calculated, Rb1 is (2.046), Rb2 is (1.869), and Rb3 is (1.624), with (1.852) Rb mean value. Secondly categorize deals with areal parameters; The longitudinal drainage density was (0.259 km??), the drainage frequency was (0.035 stream /km²), Drainage Texture value was (0.338 stream / km ), the elongation ratio was (0.483), the circularity ratio value was (0.244), the form factor was (0.183) , and the relief ratio was (0.447). according to these quantitative results the flood hazard in the basin main stream is absent, basin soil is high permeable and region rainfall rate is very low, there is significant differences in region geological structures solidity, land steepness and relief ratio are low valued yielding a few water erosion power, sediment yield, and runoff flood peak in the basin water catchment area.

Morphometric analysis of river subwatersheds using geographic information system and principal component analysis, northeast of Algeria

In the present paper an attempt is made to study the morphometric characteristics of five watersheds which are part of Seybouse and Coastal basin of Constantine located in northeast of Algeria. The study focuses on evaluating the effect of morphometric parameters on land degradation. The Geographical Information Systems which represent efficient tools in determination of drainage basin morphometric properties and principal component analysis are applied to ten geomorphic parameters on twenty subwatersheds, to group the parameters under different components based on significant correlations. Some morphometric parameters are computed and analyzed such as basin area, drainage density, stream frequency, form factor, orographic coefficient, hypsometric integral, and lithology index, basin slope, average overland flow distance, basin relief ratio. Outcomes of the matrix of correlation and principal component analysis of ten geomorphic parameters clearly depict that fifty percent of the variables are strongly correlated with the components like basin area, drainage density, stream frequency, orographic coefficient and relief ratio. It has been found that Guis sub-basin, three sub-basins of the Saf Saf watershed and all the sub-basins of the Mellah watershed are subjected to high land degradation, thus, creating an urgent need for applying soil and water conservation measures.

Estimación de la severidad en incendios forestales a partir de datos LiDAR-PNOA y valores de Composite Burn Index

Mediterranean pine forests in Spain experience wildland fire events with different frequencies, intensities, and severities. An estimation of the fire severity as accurate as possible is required by forest managers to decide which strategy is most appropriate to mitigate the effect of fire. The aim of this research is to estimate the post-fire severity, relating a pool of independent variables derived from the LiDAR (Light Detection And Ranging) points clouds delivered by the National Plan for Aerial Orthophotography (PNOA) to field data based on Composite Burn Index collected in four fires located in Aragón (Spain). Logistic regression models were developed and statistically tested and validated to map fire severity with up to 85.5% accuracy. The canopy relief ratio and the percentage of all returns above one meter height were the most significant variables. In addition, the obtained results are compared to different spectral indices derived from Landsat Thematic Mapper.

Are We Providing Enough to Those Who Have Too Little? Measuring Poverty Relief

This manuscript presents a new measure of safety net program effectiveness—a “poverty relief ratio”—that is based on the estimated relationship between market income and social transfers, and reports the amount of income support provided, relative to the amount required to provide for all low-income households’ basic needs. In an important advance over the standard poverty reduction rate measures, the poverty relief ratio preserves the rank order of observations across varying poverty thresholds. In this paper, we introduce this measure and demonstrate its validity by tracking major changes in federal policy and cross-state variation in safety net programs.