Prioritization of sub-watersheds based on morphometric and land use analysis using remote sensing and GIS techniques

Watershed prioritization has gained importance in natural resources management, especially in the context of watershed management. Morphometric analysis has been commonly applied to prioritization of watersheds. The present study makes an attempt to prioritize sub-watersheds based on morphometric and land use characteristics using remote sensing and GIS techniques in Kanera watershed of Guna district, Madhya Pradesh. Various morphometric parameters, namely linear and shape have been determined for each sub-watershed and assigned ranks on the basis of value/relationship so as to arrive at a computed value for a final ranking of the sub-watersheds. Land use/land cover change analysis of the sub-watersheds has been carried out using multi-temporal data of IRS LISS II of 1989 and IRS LISS III of 2001. The study demonstrates the significant land use changes especially in cultivated lands, open scrub, open forest, water bodies and wastelands from 1989 to 2001. Based on morphometric and land use/land cover analysis, the sub-watersheds have been classified into three categories as high, medium and low in terms of priority for conservation and management of natural resources. Out of the seven sub-watersheds, two sub-watersheds viz., SW1 and SW6 qualify for high priority, whereas SW7 has been categorised as medium priority based on the integration of morphometric and land use change analysis.     

Seismicity assessment of Fukushima region,fault kinematics and calculation of PGA value for Idosawa fault in Hamadori area,Japan

Natural Hazards - In depth assessment of seismicity distribution for a particular region like Fukushima, prefecture is key towards reliable seismic hazard analysis for the area. Assessment of...     

GIS-based spatial landslide distribution analysis of district Neelum,AJ&K,Pakistan

Natural Hazards - The Landslide happens in mountainous regions due to the catastrophe of slope through intensive rain and seismicity. The Himalayas is one of the susceptible parts of the world in...     

Changes in monsoon precipitation patterns over Bangladesh and its teleconnections with global climate

Theoretical and Applied Climatology - Understanding changes in monsoon precipitation patterns is crucial as it determines the occurrence, intensity, and duration of floods and droughts in...     

Landslide susceptibility mapping using an integrated model of information value method and logistic regression in the Bailongjiang watershed,Gansu Province,China

Bailongjiang watershed in southern Gansu province, China, is one of the most landslide-prone regions in China, characterized by very high frequency of landslide occurrence. In order to predict the landslide occurrence, a comprehensive map of landslide susceptibility is required which may be significantly helpful in reducing loss of property and human life. In this study, an integrated model of information value method and logistic regression is proposed by using their merits at maximum and overcoming their weaknesses, which may enhance precision and accuracy of landslide susceptibility assessment. A detailed and reliable landslide inventory with 1587 landslides was prepared and randomly divided into two groups, (i) training dataset and (ii) testing dataset. Eight distinct landslide conditioning factors including lithology, slope gradient, aspect, elevation, distance to drainages, distance to faults, distance to roads and vegetation coverage were selected for landslide susceptibility mapping. The produced landslide susceptibility maps were validated by the success rate and prediction rate curves. The validation results show that the success rate and the prediction rate of the integrated model are 81.7 % and 84.6 %, respectively, which indicate that the proposed integrated method is reliable to produce an accurate landslide susceptibility map and the results may be used for landslides management and mitigation.     

Addition of Phosphorus and Nitrogen Support the Invasiveness of Alternanthera Philoxeroides Under Water Stress

Coordination of plant functional traits with changes in the environment is helpful to understand the mechanisms underlying both invasiveness and adaptation of plants. Thus, to investigate the performance and functional traits in invasive Alternanthera philoxeroides (Mart.), an experiment of water stress is conducted with different nutrient concentrations. Alternanthera philoxeroides plants are grown under natural and nutrient soils and subjected to three levels of nitrogen (N) and phosphorus (P) solution: ambient P and N concentration (P?N?), P addition with an ambient N concentration (P+N?), and P addition with high N concentration (P+N+) in combination with three different irrigation water levels as 1) 100% irrigation, 2) 50% irrigation, and 3) 25% deficit irrigation. Based on results, A. philoxeroides produces significantly higher biomass in both soils under 100% irrigation with P+N? treatment and exhibits higher values of leaf area and root length. However, 25% irrigation with P?N? treatment in both soils exerts a significant negative effect on relative growth rate and root/shoot ratio of A. philoxeroides plants. Under 50% irrigation in soils with both P+N? and P+N+ treatments, high values of leaf nitrogen are recorded. Moreover, nutrient soil is more supportive to A. philoxeroides than natural soil.     

Spatio-temporal land cover changes in a semi-arid watershed: Central India

Land use/land cover change is a global phenomenon which reflects natural resources degradation and/or utilization. Remote sensing and GIS have been widely used to monitor such changes at watershed level. The present study evaluates the LU/LC change during 1989 - 2001 in a semi-arid watershed of central India. Geocoded satellite data of 1989 and 2001 on 1:50,000 scale, were visually interpreted to prepare thematic maps which were later digitized using ArcGIS softwares. The analysis shows that vast tracts of cultivated land have become uncultivated and at some places even converted to wasteland. However, the land under dense forest and open forest has decreased due to expansion of built-up land and other anthropogenic activities. Increase in area of uncultivated land, wasteland and decrease in cultivated land and open scrub is also supported by rainfall analysis, which shows a declining trend and a fall of 186.93 mm in average annual rainfall for 1986-2003 period. The change detection map prepared using land use/land cover of 1989 and 2001 as inputs shows that out of the total geographical area of the watershed, 25.78% of the watershed area has seen a change from one land use category to another, however rest 74.22% has remained unchanged.     

Mechanisms involved in triggering debris flows within a cohesive gravel soil mass on a slope: a case in SW China

The triggering mechanisms of debris flows were explored in the field using artificial rainfall experiments in two gullies, Dawazi Gully and Aizi Gully, in Yunnan and Sichuan Provinces, China, respectively. The soils at both sites are bare, loose and cohesive gravel-dominated. The results of a direct shear test, rheological test and back-analysis using soil mass stability calculations indicate that the mechanisms responsible for triggering debris flows involved the decreases in static and dynamic resistance of the soil. The triggering processes can be divided into 7 stages: rainfall infiltration, generation of excess runoff, high pore water pressure, surface erosion, soil creep, soil slipping, debris flow triggering and debris flow increment. In addition, two critical steps are evident: (i) During the process of the soil mass changing from a static to a mobile state, its cohesion decreased sharply (e.g., the cohesion of the soil mass in Dawazi Gully decreased from 0.520 to 0.090 kPa, a decrease of 83%). This would have reduced the soil strength and the kinetic energy during slipping, eventually triggered the debris flow. (ii) When the soil mass began to slip, the velocity and the volume increment of the debris flow fluctuated as a result of the interaction of soil resistance and the sliding force. The displaced soil mass from the source area of the slope resulted in the deposition of a volume of soil more than 7 - 8 times greater than that in the source area.     

Groundwater level estimation in northern region of Bangladesh using hybrid locally weighted linear regression and Gaussian process regression modeling

Theoretical and Applied Climatology - Urban groundwater resources (GWRs) have declined substantially in recent decades, due to rapid urbanization, population growth, groundwater exploitation, land...