Assessment of groundwater contamination from land-use/cover change in rural-urban fringe of national capital territory of Delhi (India)

This study examines the relationship between groundwater depletion/pollution and land-use/cover change in rural-urban fringe of Delhi, where agro-ecosystems and populations are dependent on access to reliable groundwater supplies. Results indicate a significant relationship between high proportionate decrease in groundwater and land being removed from irrigation. The higher values of most of the parameters were found in the agricultural field and industrial area. The study results suggest that most of the elements exceeding the general acceptable limit. This indicates the land-use/cover change from agriculture to industrial and residential area and also the impact of excess use of chemical fertilizer/pesticides in agricultural land

Assessment of groundwater contamination from land use/cover change in rural-urban fringe of National Capital Territory of Delhi (India)

This study examines the relationship between groundwater depletion/pollution and land-use/cover change in rural-urban fringe of Delhi, where agro-ecosystems and populations are dependent on access to reliable groundwater supplies. Results indicate a significant relationship between high proportionate decrease in groundwater and land being removed from irrigation. The higher values of most of the parameters were found in the agricultural field and industrial area. The study results suggest that most of the elements exceeding the general acceptable limit. This indicates the land-use/cover change from agriculture to industrial and residential area and also the impact of excess use of chemical fertilizer/pesticides in agricultural land

Indigenous knowledge of terrace management for soil and water conservation in the Sikkim Himalaya, India

The main objective of this study was to understand the farmer’s indigenous knowledge of terrace management in the Sikkim Himalaya with reference to Rani Khola watershed. Primary data were collected through a mix of questionnaire surveys, focused group discussions, and field observations with a sample size of 300 households. Detailed documentation of the evolution of the terraces and their types, bunding material, types of risers, the relationship of slope and terraces dimensions, soil and water conservation (SWC) practices were performed. Remote sensing data was used to derive information pertaining to elevation, slope and land-use/cover of the watershed. The study reveals that dimensions and types of terraces are subjected to the elevation, slope gradient, local soil and vegetation cover. Leveled terraces were constructed on lower slopes while outward sloping terraces were more common on higher slopes. It was also observed that with the increase in slope angle, width and length of the terraces decreased. Terrace riser height was also correlated with slope; riser height unavoidably increased as slope increased. The study concludes that terraces in the study watershed are effective in reducing the slope gradient and length, and in turn helpful in trapping eroded soil, slowing soil movement and in due course reducing soil erosion and increasing agricultural productivity. It is suggested that for overall management of terraces, it needs to be combined with additional soil and water conservation practices

Indigenous knowledge of terrace management for soil and water conservation in the Sikkim Himalaya, India

475-485The main objective of this study was to understand the farmer’s indigenous knowledge of terrace management in the Sikkim Himalaya with reference to Rani Khola watershed. Primary data were collected through a mix of questionnaire surveys, focused group discussions, and field observations with a sample size of 300 households. Detailed documentation of the evolution of the terraces and their types, bunding material, types of risers, the relationship of slope and terraces dimensions, soil and water conservation (SWC) practices were performed. Remote sensing data was used to derive information pertaining to elevation, slope and land-use/cover of the watershed. The study reveals that dimensions and types of terraces are subjected to the elevation, slope gradient, local soil and vegetation cover. Leveled terraces were constructed on lower slopes while outward sloping terraces were more common on higher slopes. It was also observed that with the increase in slope angle, width and length of the terraces decreased. Terrace riser height was also correlated with slope; riser height unavoidably increased as slope increased. The study concludes that terraces in the study watershed are effective in reducing the slope gradient and length, and in turn helpful in trapping eroded soil, slowing soil movement and in due course reducing soil erosion and increasing agricultural productivity. It is suggested that for overall management of terraces, it needs to be combined with additional soil and water conservation practices

Catastrophic Ice-Debris Flow in the Rishiganga River, Chamoli, Uttarakhand (India)

A catastrophic flood occurred on 7 February 2021 around 10:30 AM (local time) in the Rishiganga River, which has been attributed to a rockslide in the upper reach of the Raunthi River. The Resourcesat 2 LISS IV (8 February 2021) and CNES Airbus satellite imagery (9 February 2021) clearly show the location of displaced materials. The solar radiation observed was higher than normal by 10% and 25% on 6 and 7 February 2021, respectively, however, the temperature shows up to 34% changes. These conditions are responsible for the sudden change in instability in glacier blocks causing deadly rock-ice slides that led to the collapse of the hanging glacier as a wedge failure. The displaced materials mixed with ice, snow, and debris caused catastrophic floods downstream within no time that destroyed critical infrastructure and killed human lives. The hydrodynamic modelling (HEC-RAS software) shows mean flow velocity up to 22.4 ± 8.6 m/s with an average depth of 16.3 ± 6.5 m that caused deadly devastation in the source region and along the rivers due to the flow of water in the valley

Hydrogeochemical characterization and quality assessment of groundwater resources in the Upper-Doab region of Uttar Pradesh, India

The present study tries to delineate groundwater zones in the Upper-Doab region of Uttar Pradesh, India based on its suitability for the use of domestic and irrigation purposes considering the physico-chemical parameters of groundwater samples (n ∼ 70) using Weighted Arithmetic Water Quality Index (WAWQI) and Composite Groundwater Quality Index for Irrigation (CGQII) methods, respectively. The Upper-Doab region of Uttar Pradesh is bounded by the mighty rivers of Ganga and Yamuna in the east and west respectively. In the southwest, the region shares the boundary with the national capital of Delhi, which has led to an increase in the growth of urbanization and industrialization in the region. These factors have a visible negative impact on the groundwater scenario of the region. Hydrogeochemical investigation reveals that the ionic dominance in the groundwater samples is in the order of HCO3 > Cl > SO4 > NO3 > F and Na > Mg > Ca > K. Chemical history of groundwater samples using piper-trilinear diagram shows that Ca-Mg-HCO3 and Ca-Na-HCO3 type of groundwater is mostly found in this region. Gibb’s plot reveals that rock-water interaction was dominantly controlling the ionic composition of the groundwater in the unconfined aquifer environment. Further, the bivariate plot of (SO4 + HCO3) vs. (Ca + Mg) reveals that the weathering of calcite and dolomite minerals present in the aquifer environment has largely attributed chemical character to the groundwater of the region. The groundwater zoning concerning its domestic and agricultural use reveals that the groundwater of Meerut, Muzaffarnagar, Baghpat, Ghaziabad, and Gautam Buddha Nagar districts have poorer quality of groundwater due to high electrical conductivity and higher concentration of nitrate which has a higher anthropogenic link. The evaluation of groundwater quality for irrigation using a single index value i.e., CGQII makes this study different from the other hydrochemical investigations under similar hydrogeolocal aquifer conditions in the region. The study suggests that corrective measures like, strict implementation of untreated discharge of industrial effluents to the water or groundwater directly, creating awareness among farmers for lesser use of chemical fertilizers, and regular groundwater monitoring systems for quality analysis must be considered for a sustainable future of the region

Analysing Challenges and Strategies in Land Productivity in Sikkim Himalaya, India

Agriculture is the major source of livelihood in rural areas and is considered the backbone of the Indian economy. In Sikkim, agriculture is being practiced by 80% of the rural population, and having no other major livelihood options has created immense pressure on the farmers and agricultural land. Agriculture sector is under great stress as the farmers are being confronted by various challenges in Sikkim Himalaya in recent years, such as land degradation, climate change and socio-economic problems. Despite the number of indigenous agriculture management methods being practised in Sikkim Himalaya, the agricultural production system is weakening. In this context, this paper presents an analysis of challenges faced by indigenous communities, local farmers and potential sustainable strategies for their management in Rani Khola watershed of Sikkim Himalaya. Data and information were collected by field observation, questionnaire surveys of 300 households, key informant interviews and focus group discussions conducted during 2017–18. Data processing and analysis were carried out with a combination of techniques, such as the application of remote sensing (RS), geographic information system (GIS)-based data processing and descriptive statistics. Major challenges identified in the watershed are water scarcity (80%), climate change (88%), soil erosion and runoff (72%), higher investment cost (100%), lack of irrigation facilities (77%), fragmentation and size of landholdings (100), human–wildlife conflict (59%) and pests and disease (60%). Some possibilities and innovations that could address these problems are the use and retaining of various indigenous soil and water conservation (SWC) measures, diversified farming systems, community involvement in the government development process, better irrigation facilities, strengthening the local economy, coordinated planning between stakeholders and development of market feedback mechanism within the system

Land Degradation, Overland Flow, Soil Erosion, and Nutrient Loss in the Eastern Himalayas, India

Studies on the assessment of land degradation, overland flow, soil loss, and nutrient loss have emerged as paramount importance for food security and rural livelihood in the mountains. The present study dealt with similar issues in the Eastern Himalayas, for which the primary data were collected from the field during 2017–18. Quantitative and qualitative methods were used to collect data on soil erosion and information on overland flow, soil loss, and nutrient loss was assessed through field experiments in the watershed of Sikkim, Eastern Himalayas. The first section of the methodology deals with the experimental analysis from different land use categories to quantify soil loss. In the second section, detailed qualitative analyses of farmers’ perceptions of soil erosion indicators were recorded through field surveys, i.e., key informant interviews (KEIs) and focus group discussions (FDGs). The results showed that the highest overland flow was in barren land (8.63%) followed by large cardamom-based agroforestry system (7.02%), and mixed cropping (4.84%), and the lowest overland flow was in terrace cultivation (4.69%). Soil loss was estimated to be the highest for barren land (7.73 Mg/ha/year (megagram/hectare/year)) followed by mixed cropping (4.32 Mg/ha/year), and terrace cultivation (3.75 Mg/ha/year), with the least soil loss estimated to be in cardamom-based agroforestry (3.23 Mg/ha/year). Loss of nitrogen (N) (4.49 kg/ha/year) and phosphorous (P) (2.43 kg/ha/year) were highest in barren land, while potassium (K) loss was highest (4.30 kg/ha/year) in mixed farming. The lowest N loss rate (3.34 kg/ha/year) was in terrace cultivation, the lowest P loss rate (8.19 kg/ha/year) was in mixed farming, and the lowest potassium loss rate (3.28 kg/ha/year) was in cardamom-based agroforestry. Approximately 33% of the farmers acknowledged light or no soil losses, while 17% of the farmers accepted moderate soil erosion. The results of field survey indicated that only 15–19% of the farmers reported high or extreme soil loss in the fields. Farmers in the watershed are practicing multiple measures to control land degradation; however, marginal farmers are still vulnerable and need strong support from the government to safeguard their land

Evaluating geo-hydrological environs through morphometric aspects using geospatial techniques: A case study of Kashang Khad watershed in the Middle Himalayas, India

The present study analyzes the geo-hydrological behaviour of the Kashang khad basin of the satluj river system in Kinnaur district, Himachal Pradesh. The major source of water in the region is the snowmelt, which contributes to the evolution of a drainage pattern. It highlights the importance of ASTER GDEM and satellite images for assessing and understanding the various geo-hydrological parameters such as drainage analysis, and topographic analysis for better basin management. Hydrological modelling of ArcGIS 10.5 has been used for the delineation and analysis of basins using SRTM DEM with 30 m resolution. Morphometric parameters like linear, relief, and aerial further help in the micro-level study of its physiographic characteristics and structural control of flow along with runoff, which can help predict floods, their extent, and intensity. It was found that the basin had a dendritic pattern with uniform lithology. The stream order ranges from 1st order to 5th order signalling homogeneity in texture and medium to high drainage density meaning permeable soil and good surface runoff. The drainage texture of 2.19 indicates the basin is prone to weathering and erosion. The bifurcation ratio ranges from 4.43 to 5.23, with a mean Rb of 4.82 showing the structural control on the elongated basin with Re of 0.56. The ASTER DEM and sophisticated morphometric attributes and hydrological environs can be effectively utilized in watershed management and other hydrological studies in higher mountainous regions

Trap Assisted Carrier Recombination in 4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran Doped Bis[2-(2-hydroxyphenyl)bezoxazolate] Zinc

The energy transfer mechanism has been studied in 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyram (DCM) doped zinc complex bis[2-(2-hydroxyphenyl) bezoxazolate]zinc [Zn(hpb)2]. The photoluminescence of the zinc complex and the optical absorption of the dye molecule have been found to have a large overlap favoring Förster mechanism for energy transfer from the host to the dye molecule. The photoluminescence of the host–guest system has been assigned to Förster type energy transfer where as the electroluminescence has been found to be dominated by trap assisted recombination and subsequent decay of excitons. The charge carrier trapping has been supported by electrical transport studies