A sewage and sludge treated lake and its impact on the environment, Mysore, India

Water, soil, suspended load and biomass samples were collected from a sewage and sludge treated lake (Lake Dalavayi) around Mysore, Karnataka, India. The polluted lake water is mainly used for irrigation and domestic purposes. The samples have been analysed for heavy metals (Cu, Cr, Co, Cd, Ni, Fe, Mn, V, Zn, Sr) and cations (Ca, Na, Mg) by Inductively Coupled Plasma Emission Spectrometer (ICP) model Labtam 8500. With the exception of water, all the matrices suspended particulate matter, lake bed sediment and biomass of the lake show high concentrations of heavy metals and cations when compared to the World Health Organization (WHO) standard, indicating metal toxicity in this lake. Additional inputs of soaps and detergents carried by sewage water are causing the eutrophication of the lake. Elevated levels of heavy metal toxicity, especially Co and Cd, are indicated by the bioindicator Eichornia cressepes (water hyacinth), which, using these metals as micronutrients, has grown luxuriously over the lake water, further augmenting the death of lifeforms in the lake.     

Influence of groundnut shell ash on strength and durability properties of clay

Groundnut shell ash, cement and their combinations are used as soil stabilizers in various percentages to improve the strength of locally available highly compressible clay soil. The effect of stabilizer in improving the strength of the soil is evaluated through change in consistency limits, compaction characteristics, undrained cohesion and modulus of elasticity. The durability characteristics of stabilised soil were studied based on the improvement of undrained shear strength for various days of curing by increasing the percentage of cement. Stabilised soil showed satisfactory improvement in strength and consistent durability characters. Groundnut shell ash and cement increased the optimum moisture content. There was a slight decrease in the dry density and modulus of elasticity of soil. These can be used as a viable economic alternative in construction of roads and for stabilising soil acting as bearing medium. The use of groundnut shell ash, an agricultural waste, helps in waste management and promotes sustainable development of local construction industry.     

Landslide susceptibility analysis using probabilistic likelihood ratio model—a geospatial-based study

The crucial and difficult task in landslide susceptibility analysis is estimating the probability of occurrence of future landslides in a study area under a specific set of geomorphic and topographic conditions. This task is addressed with a data-driven probabilistic model using likelihood ratio or frequency ratio and is applied to assess the occurrence of landslides in the Tevankarai Ar sub-watershed, Kodaikkanal, South India. The landslides in the study area are triggered by heavy rainfall. Landslide-related factors—relief, slope, aspect, plan curvature, profile curvature, land use, soil, and topographic wetness index proximity to roads and proximity to lineaments—are considered for the study. A geospatial database of the related landslide factors is constructed using Arcmap in GIS environment. Landslide inventory of the area is produced by detailed field investigation and analysis of the topographical maps. The results are validated using temporal data of known landslide locations. The area under the curve shows that the accuracy of the model is 85.83%. In the reclassified final landslide susceptibility map, 14.48% of the area is critical in nature, falling under the very high hazard zone, and 67.86% of the total validation dataset landslides fall in this zone. This landslide susceptibility map is a vital tool for town planning, land use, and land cover planning and to reduce risks caused by landslides.     

Effects of the Herbicide Metazachlor on Phytoplankton and Periphyton Communities in Outdoor Mesocosms

The effects of the chloroacetanilide herbicide metazachlor have been investigated in outdoor artificial mesocosms. Decreasing phytoplankton densities were caused by the application, however, the communities recovered after 30 to 35 days. Periphyton growth was found to be affected not only by the herbicide application but by the presence of species with different ability to grow on artificial substrates. Zooplankton diversity was small due to low density of ingestible algae species. Oxygen saturation was found to be correlated with the dosage levels of the herbicide in the second half of the study.     

Providing new homes for climate change exiles

Abstract

Given a certain pre-existing commitment to sea-level rise due to the long thermal lags of the ocean system, several million people living in coastal areas and small islands will inevitably be displaced by the middle of the century. These climate exiles will have nowhere to go. Rather than deal with this in an ad hoc manner as the problem arises, the authors propose a mechanism by which these exiles would be given immigration benefits by countries through a formula that ties numbers of immigrants to a country's historical greenhouse gas emissions. Such a compensatory mechanism appears to be a fair way of addressing the problems faced by climate exiles.     

Spatial distribution and geochemical baselines of major/trace elements in soils of Medak district,Andhra Pradesh,India

Regional-scale variations in soil geochemistry were investigated with special reference to differences among soil groups and lithology in an area of 9,699 km² in Medak district, Andhra Pradesh, India. The concentrations of 29 elements (major: Si, Al, Fe, Mn, Mg, Ca, Na, K, Ti, P and trace: As, Ba, Cd, Co, Cr, Cu, F, Mo, Ni, Pb, Rb, Se, Sr, Th, U, V, Y, Zn, Zr) in 878 soil samples collected (557-topsoil, 321-subsoil) at a sampling density of 1 site/17 km² from 557 sites representative of all the soil types present in studied area were determined, and their elemental composition are discussed. The baseline levels of these elements in soils are determined over different lithological units for the identification of anomalous values relative to these. For the first time, geochemical maps for Medak district are prepared on 1:50,000 scale and the lithogeochemical database generated provides information on the lateral and vertical distribution of elements in soil. The spatial variations in the distribution of elements reflect underlying geologic characteristics. Box-plots reveal that the concentration of most of the elements in soils were not strongly dependent on the soil group but the soil-geochemistry abruptly changes with the change in the soil parent materials indicating that the distribution of elements is mostly influenced by the bedrock lithology and other natural processes acting on them. For instance, the concentrations of Co, Cu, Fe, Mn, Ti, V and Zn are high in soils developed on basaltic terrain while the soils developed on granitic and gneissic terrain exhibit high elemental concentrations of K, Pb, Rb, Si, Th and Y. Alfisols had relatively high contents of elements while entisols had lower concentrations of most of the elements. The database can be used in the chemical characterisation of different geological units as well as applications in various environmental and agricultural fields. The results indicate that regional geology is an important determinant of soil geochemical baselines for soil pollution assessment and further emphasizes the importance of determining background levels locally. The defined baselines can be used to establish background values for future soil surveys.     

Spatial Assessment of Soil Organic Carbon Density Through Random Forests Based Imputation

Regional estimates of soil carbon pool have been made using various approaches that combine soil maps with sample databases. The point soil organic carbon (SOC) densities are spatialized employing approaches like regression, spatial interpolation, polygon based summation, etc. The present work investigates a data mining based spatial imputation for spatial assessment of soil organic carbon density. The study area covers Andhra Pradesh and Karnataka states of India. Field sampling was done using stratified random sampling method with land cover/use, soil type, agro-ecological regions for defining strata. The spatial data at 1 km resolution on climate, NDVI, land cover, soil type, topography was used as input for modeling the top 30 cm Soil Organic Carbon (SOC) density. To model the SOC density, a Random Forest (RF) based model with optimal parameters and input variables has been adopted. Experiment results indicate that 500 number of trees with 5 variables at each split could explain the maximum variability of soil organic carbon density of the study area. Out of various input variables used to model SOC density, land use / cover was found to be the most significant factor that influences SOC density with a distinct importance score of 34.7 followed by NDVI with a score of 12.9. The predicted mean SOC densities range between 2.22 and 13.2 Kg m^?2 and the estimated pool size of SOC in top 30 cm depth is 923 Tg for Andhra Pradesh and 1,029 Tg for Karnataka. The predicted SOC densities using this model were in good agreement with the measured observations (R?=?0.86).     

Watershed prioritization of Palar sub-watershed based on the morphometric and land use analysis

Morphometric analysis is an indispensable tool for hydrological investigation that involves the development and management of drainage basin. This study characterizes the micro watersheds in the Palar sub-watershed using morphometric analysis and assesses its risk by land use and land cover features in a particular micro watershed. Palar sub-watershed is divided into 6 micro watersheds for prioritization based on morphometric and land use analysis. Several morphometric parameters （linear, shape and relief） are determined from the drainage map; ranks are assigned based on their capacity to induce erodability and degradation. Final ranking is based on the composite index calculated from the sum of the ranks of each morphometric parameter. Morphometric analysis reveals micro watersheds 5 and 6 as most susceptible and 2 and 3 as low susceptible. Land use is mapped using IRS ID LISS III satellite data. The risk in terms of watershed degradation involved to each micro watershed is based on the ranks of each land use feature, obtained from a similar composite index as that of morphometric analysis. Land use analysis shows that micro watersheds 2 and 4 fall under high priority category while 5 and 6 under low priority category. Integration of the morphometric and land use analysis shows that only microwatershed 1 falls under the same category in both analyses. Control measures are suggested to contain degradation depending on its specific land use pattern and morphometric features. This study ean be used to prepare a comprehensive watershed plan for the development or for planning resource conservation strategies, by integrating land use features with the drainage characteristics of the region, in particular for a hill ecosystem as the prioritization is at micro level.     

Fish detection and identification using neural networks-somelaboratory results

Tests on laboratory data on the use of neural networks to detect and identify fish from their sonar echoes are reported. Results are quite encouraging; simple three-layer perceptrons trained on a portion of the data set are able to recognize over 80% of the targets on the remainder of the data set. Parallel networks are found to be very effective, and a parallel combination of two networks (feature fusion), one trained on the original data and the other trained on the data preprocessed through a peak detector, performs significantly better than either network acting alone. In the test cases, over 90% of the targets were identified correctly by the parallel combination. In the simpler detection problem, where the objective is only to detect the presence of fish and not make a complete identification, success rates of over 98% were obtained using a parallel combination as described above. For the fish detection problem, with incomplete training data, correct responses are still obtained in over 95% of the test cases     

Key morphological changes and their linkages with stream power and land-use changes in the Upper Tapi River basin,India

Knowledge on spatio-temporal variations in planform, hydraulic geometry, and bed-level variations of alluvial streams is required for planning and development of hydraulic structures and bank protection works. In the current study, a Geographic Information System (GIS) has been used to analyze topographical maps, multi-temporal remotely sensed imagery, and hydrologic and hydraulic data to extract the morphological parameters of the Upper Tapi River, India. The river has been found to have consistent migration towards the northern direction, with erosion/deposition on right/left banks. The river has not experienced any major meander except in the lower reaches of the Upper Tapi Gorge and minor braiding conditions at the location where the river emerges from mountainous topography to the plain region. The analyzed river cross sections were found to be depth dominated, and contain large flows within the channel banks. The cross-sections exhibited moderate channel bed adjustments in 1994, 2006, and 2007 wherein excessive sediment flux and stream power were capable of causing morphological changes in the river. High intensity rainfall in the subcatchment resulted in high sediment flux into the river during 1994, which was reported to cause significant aggradation at the downgauging station. The analysis of sediment flux into the river in conjunction with decadal land use land cover, revealed that sediment yield from the catchment was reduced during 2000–2010 due to an increase in water bodies in the form of minor hydraulic structures. The entry of comparatively less sediment laden water into the river, resulted in moderate bed degradation especially in 2006 and 2007 as observed at the downstream station. The methodology applied in the current study is generic in nature and can be applied to other rivers to identify their morphological issues.