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The integration of remote sensing data, machine learning and geographic information system in managing and analysing spatial data helps in generating maps showing groundwater potential. These maps are important tools for aiding stakeholders and decision-makers in groundwater resources to make informed decisions during groundwater development and management; to ensure the reliability of these maps, validation with the field data is conducted. This study analysed 125 scientific articles spanning the period from 2002 to 2023. The results show that around 85% of articles contain validated maps, indicating a significant number of researchers adhere to validate the remote sensing and GIS-based maps with field data, which is crucial in scientific research. However, 15% of articles contain non-validated maps. This is an alarming figure; therefore, journals should be strict in ensuring that validation is adhered to. In the reviewed articles, a total of 10 methods were used to validate groundwater potential maps using various parameters such as well yield, well/spring discharge rate, aquifer transmissivity, well specific capacity, and presence of wells/springs. This study will also add to the knowledge of selecting appropriate methods for validating remote sensing and GIS-based groundwater potential maps. The use of field data reflecting aquifer productivity is more appropriate for validation of groundwater potential maps.

This study involved a comparative analysis in the groundwater vulnerability domain, which is a crucial component of groundwater management decision support systems (DSS). This was achieved by creating models that covered the range of algorithms from the subjective to the data-driven. The study was conducted in a basement complex area. Databases of climatic, remote sensing, and geophysical datasets were created using varieties of data acquisition techniques. The datasets included in this assessment were: rainfall (R), land use (LU), bedrock topography (BT), recharge rate (Re), and slope (S). The slope and rainfall were determined to have the highest (0.78) and lowest (0.01) weighted factors, respectively, using the entropy method. For the development of the TOPSIS-Entropy model algorithm, the weights results were combined with the TOPSIS outranking method. To generate the Groundwater Vulnerability Model map of the study area, the hybrid model was applied to griddled raster layers of the factors. Also, the TOPSIS and Entropy-WLA model algorithms were also explored and used to generate groundwater vulnerability maps. The TOPSIS-Entropy algorithms produced an accuracy of 70%, while TOPSIS and Entropy-WLA produced accuracy of 50 and 47%, respectively. The resulting model maps were validated by using correlation technique on the produced map and the longitudinal conductance map of the study area. The TOPSIS-Entropy, which followed an object-oriented model pattern, demonstrates greater accuracy and has the potential to provide appropriate insights and alternatives to decision-making in the field of groundwater hydrology in the study area and other regions of the world with comparable geology.

The northwestern side of Sikkim Himalayas is selected to study the climatic variability. In this study, the regional assessment of glacier lakes area increasing over the 30 years is calculated and correlated with the land surface temperature using Geospatial technology in the North West Sikkim Himalaya. For this site, glacier lakes have been mapped with Landsat (4–5) MSS/TM and Landsat 8 (OLI) satellite imagery acquired in the years 1990, 1995, 2000, 2005, 2010, 2015 and 2020. The glacier area (North Lhonak glacier, Lhonak glacier, and South Lhonak glacier) and the glacier lakes area are calculated for the given years, and found that area of the glacier is shrinking and area of the Lhonak and South Lhonak lake is increasing over the years. The land surface temperature of the area was calculated in this study to determine the rate at which the temperature of the area has increased over the years. Due to surface temperature rise, the glaciers are melting, and this melting of glaciers is increasing the area of Lhonak glacier lake and South Lhonak glacier lake. Remote sensing and GIS technique are very helpful to evaluate the risk assessment of GLOFs for remote mountainous areas.

Regulations for land use monitoring in Indonesia are still centered on how to increase production as high as possible, without intensively and carefully securing the soil as a sustainable planting medium. Several approaches have been developed, and the concept of soil security which has emerged in several developed countries, is one of the alternative solutions upheaved that need to be modified to ensure soil sustainability in this tropical environment. The geographical approach using remote sensing and GIS is examined to answer the challenges of the broad and diverse characteristics of Indonesia. This study aims to identify the existing approaches related to land capability assessment for agricultural food commodities, and to be able to develop a method to quantify the soil capability, condition, and capital under the concept of soil security, in Central Java, Indonesia. Parameters used in calculating the capability include land use, rainfall, and soil properties, which are derived from various data, including remote sensing data. The result shows that Central Java has a great potential for agriculture purposes indicated by the high score of soil capability. However, the soil condition and capital status need more support from regulation to be sustainable both physically and economically. Soil security classes as a foundation to establish new regulations will comprehensively codify the importance of strengthening the security of soil and thus of food. Using freely available data, our study can be scaled up to provide a national spatial database on soil security status, and to sustain food security in the country.

Surface water monitoring is a necessary component of researching ecological and hydrological processes. Recent improvements in satellite-based remote sensors have ushered in a new era in the area of surface water monitoring. The assessment and mapping of water resources in the semi-arid regions are one of the challenging tasks for the research domain of hydrogeologists and decision-makers. In this study, an inventory of existing ancillary data and remotely sensed data, i.e., Landsat 7 ETM+, Landsat 8 OLI/TIRS, and DEM data used for monitoring and mapping the surface water resources in the semi-arid regions of south India. For monitoring and mapping the water resources, twenty years of land cover changes were assessed using the Modification of Normalized Difference Water Index (MNDWI) techniques. Each MNDWI land cover has been classified into five categories viz., fallow land, vegetation land, developed land, moisture soils, and surface water bodies, based on the pixel values varying from +1 to -1. The results of the research reveal that the surface water bodies vary from year to year over the past two decades. The fallow land (36.20 %), vegetation lands (35.37 %) are decreased, and developed land (22.56 %), moisture soils (4.81 %), and surface water bodies (1.06 %) are increased over the past two decades from 2000 to 2020. Most land cover categories differed statistically from one another, however, when defining vegetation with varying water content, there were some commonalities. MNDWI is found to be efficient in identifying water bodies.

The analysis of morphometric parameters gives a precise scenario about the geomorphic characteristics and the hydrological behaviour of a drainage basin, especially in the areas where hydrological data are unavailable due to the absence of a gauging station or inaccessibility for harsh topographic conditions. So, the current study is aimed to investigate the hydro-geomorphic characteristics of the Rayeng basin in Darjeeling Himalaya. The extraction and analysis of the morphometric variables of the study area were done using remote sensing and GIS. The spatial disparity in drainage density, lineament density, stream frequency, texture ratio, and infiltration number has inferred that the Rayeng basin is carried a high runoff intensity and low infiltration rate on the upper reaches and an inverse situation in the lower reaches. The extracted ruggedness index and Melton's Ruggedness index indicate the unevenness of the topography and normal flow in the main channel in the Rayeng basin. A distinctive topographic diversity is also depicted by the basin's Topographic Positioning Index (TPI). A significant spatial variation of water availability in this basin is indicated by the Topographic Wetness Index (TWI); the depressed areas of the basin have higher TWI compared to the steep-sloped high land. The basin's hypsometric integral (HI) is inferred youthful stage. This basin has a good potentiality of water which can be sustainably used by the people of the lower reaches of the basin. This study will be helpful to assess the hydro-geomorphic characteristics of a drainage basin where hydrological data are not available.

Mapping and monitoring of land use land cover (LULC) changes in the Himalayas is vital for sustainable development, planning and management. Based on remote sensing (RS) and geographic information system (GIS) techniques, the study is an attempt to monitor the changes in LULC patterns of Rani Khola watershed of Sikkim Himalaya for the periods 1988–1996, 1996–2008 and 2008–2017. Images from Landsat-5 Thematic Mapper (TM) and Sentinel 2A (Multispectral Instrument) MSI data were used to extract land cover maps. Supervised classification using Maximum Likelihood Classifier (MLC) was applied to prepare LULC maps of the watershed. The accuracy of the classified map was assessed using a High Resolution Planet scope image and ground realities have been verified and ascertained through field observations and site specific interviews. As a result of policy changes and traditional agroforestry systems, LULC in the study watershed has undergone a series of complicated changes over the past three decades. Six major LULC classes viz; agriculture, barren land, built-up area, dense forest, open forests and water bodies have been identified and indicate that major land use in the watershed is forestry. Results shows, dense forest, built-up area and water bodies have increased by 16.40% (41.76 km2), 2.13% (5.41 km2) and 0.11% (0.28 km2) while open forest, agriculture and barren land have decreased by −13.98% (−35.59 km2), 2.83% (−7.22 km2) and −1.82% (0.4.64 km2) respectively. The analysis and findings of the study highlights important policy implications for the sustainable LULC management in the Rani Khola watershed of the Sikkim Himalaya.

Under the background of rapid urbanization, the change of urban land use structure has a great impact on ecological environments, and determination of impacts of urban spatial expansion (USE) on the urban ecosystem service value (ESV) is of particular significance to sustainable development in arid regions. To archive a better understanding of the spatio-temporal characteristics of USE, and to quantitatively describe the impact of USE on ESV, five typical oasis cities around the Tarim Basin are selected as research areas. Based on classifying the land use types from LandsatTM/ETM+/OLI imagery data between 1990 and 2015, the urban spatio-temporal dynamic changes are quantitatively analyzed, ESV changes of each land use types and each ecosystem functions were estimated, and USE impacts on ESV is determined. The results are concluded as follows: (1) Over the researched 25 years, the largest USE area occurred in Korla, followed by 63.65 km2, and the smallest is in Artux, followed by 2.91 km2. (2) Farmland and unused land has a great contribution to the USE, and the reduction of farmland in five cities were 2.68 km2 in Korla, 5.13 km2 in Aksu, 0.54 km2 in Artux, 28.42 km2 in Kashgar, and 14.25 km2 in Hotan during the 1990–2015 years. (3) Both of the expansion speed and expansion intensity are maximal in Hotan (followed by 8.38% and 25.89%) and minimal in Artux. (4) There are the highest compactness, the lowest fractal dimension, and the simplest and most stable shape in Artux. In contrast, Korla has the lowest compactness and highest fractal dimension, and is the most complex, disperse and unstable city. (5) The total ESV of the five cities is reduced at 45.36 million CNY with a decrease rate of −21.54%. Among these cities, only Korla shows an increasing trend of ESV (23.72 million CNY), but the other four cities shows a decreasing trend with 20.98 million CNY in Aksu, 0.15 million CNY in Artux, 35.76 million CNY in Kashgar, and 12.20 million CNY in Hotan. (6) USE has a great effect on the ESV changes, and the increasing runoff, temperature and precipitation are impacting the ESV in some positive ways. (7) Waste treatment, water conservation and soil formation functions are the top three ecosystem functions with high service value, and ecosystem function of the five cities belong to a provision function. In light of these findings, this study conveys important strategies for regional sustainable development and plan in the arid ecologically fragile regions.

ABSTRACT: Watershed management is an essential part to achieve sustainability. In the case of large watersheds, management and conservation practices cannot be implemented efficiently over the entire area due to inadequate human resources and financial support. Therefore, prioritizing the sub-watersheds and implementation of management practices would be a viable technique to ensure sustainability within the watershed. In this study, sub-watershed prioritization is carried out for the Kalinadi basin based on erosion susceptibility using morphometric analysis. SRTM DEM is used to extract stream network and delineate the sub-watersheds using ArcGIS software. Further, the Kalinadi basin is divided into eight sub-watersheds and morphometric analysis performed. In the current study, for prioritizing the sub-watersheds, nineteen morphometric parameters are considered which include linear, aerial and relief aspects. The results of linear, aerial and relief parameters of every sub-watershed are given with ranks based on their influence on soil erosion and then subjected to compound parameter analysis which is used to prioritize each sub-watershed. The morphometry-based prioritization findings demonstrate that Sub watershed-8 (SW-8), SW-4 and SW-5 face high risk, SW-6, SW-7 and SW-2 face medium risk whereas SW-3 and SW-1 face a low risk of soil erosion. The results can be used by the decision-making authorities to plan and implement the watershed management practices optimally to control soil erosion.

The biodiversity of the Cerrado biome is endangered. Ensuring its quality requires maintaining its biogeophysical characteristics, and environmental studies must consider space-time scales and sustainable perspectives to balance environmental, economic, and social needs. This study evaluates environmental conservation in a hydrographic basin in Brazil’s São Paulo state and proposes integrating two types of spatial analysis generally applied separately. The Land Change Modeler was used to model future land use by using artificial neural networks and CA-Markov. Environmental conservation levels were obtained through multicriteria evaluation for three scenarios, verified through field visits and the application of an ecological diversity protocol. Significant changes were noted, primarily related to anthropic disorders, with land use map values for 2028 indicating dominant trends in the anthropized area and silviculture. Priority areas for conservation are the reservoir, Brazilian Cerrado, wetlands, bodies of water, riparian forest, and silviculture. Fragmented natural vegetation was identified in regions with springs and high, but dispersed, values of environmental conservation. Mean and minimum values anticipated increase, indicating a tendency for degradation, which could be mitigated by incentive policies for preservation and conservation. Environmental management and inspection by public agencies are needed at reservoir sites used for recreation, tourism, and fishing. Finally, the study’s integrated methods proved satisfactory for assessing conservation dynamics and providing data to inform strategic planning for effective land use management focused on sustaining natural resources.

In the last few decades, rainfall-induced urban waterlogging has become a significant environmental barrier and acquired global prominence worldwide due to its frequent threat, which results in significant infrastructure damage and economic loss. This study aims to model and identify the waterlogging hazard, vulnerability, and risk zones in the unplanned city of Siliguri, ‘Gateway of North-east India’, with the help of an integrated Analytical hierarchy process (AHP) and GIS techniques. Due to the lack of a comprehensive database, a systematic waterlogging assessment in the Siliguri city has not yet been carried out. However, waterlogging is a seasonal phenomenon in the Siliguri city, especially during the monsoon seasons, when short-duration and high-intensity rainfall cause inundation in low-lying areas causing mayhem to the city. Therefore, in this present study, a primary field investigation was conducted to prepare waterlogging inventory map along with seventeen other parameters, including spatial and attribute data from the secondary sources to delineate waterlogging hazard, waterlogging vulnerability, and risk map. Further, the final risk map was integrated with the spatial distribution of the slums locations, revealing that a larger proportion of slum households are under high-risk zones. The results suggest that about 46% of the city is under high to very high waterlogging hazard zones, while 38% of the Siliguri is highly vulnerable to waterlogging. The final risk map reveals that around 35% of the study area is susceptible to threat of waterlogging, which is mostly concentrated in the central part of the city center. Besides, the consistency of the model was assessed by area under curve (AUC), which gives an accuracy of 0.782 or 78.2%. This study's overall strategy may be used for planning and mitigation efforts to reduce future waterlogging incidents all around the world.

Since 2016, the Chinese government has invoked some policies to make Jing-Jin-Ji (JJJ) a new urban agglomeration. However, there has been no research to study the effect of these new policies on future urban growth. This study assessed part of these new policies on JJJ urban growth in 2020–2050 using SLEUTH model. Then the ecological effects of the urban growth are evaluated. Results showed the policies had nearly no obvious impact on the whole JJJ urban growth, but affected sub-regional (Beijing, Tianjin and Hebei, respectively) urban growth. Under ecological protection in future, the value of ecological service in JJJ would increase to a maximum of 31.7×108 Yuan/km2 in 2031. The ecological elasticity also increased and the ecological risk was strongly reduced around the present urban area. This ecologically sustainable development is critical to the future urban growth, and should be considered more carefully by urban planners and managers. More policies should be evaluated for JJJ urban growth in future work.

We assessed soil site suitability for selected winter crops in the coastal saline agro-ecological environment of Sagar Island, India by integrating land limitation and crop suitability evaluation framework of FAO. Grid based (1 km by 1 km) soil sampling and estimation of important soil quality attributes were measured in the laboratory following standard procedures. Geo-statistical and visualization methods were applied to match the soil suitability for selected crops. The weights of crop specific soil parameters have been assigned through PCA analysis. The inverse distance weighting interpolation and reclassification methods were adopted for generation of spatial layers of those soil attributes. Nearly 61% area (14,618 ha GA) of the Island is under agricultural landuse (AL), mostly dominated (>75% of AL) by lowland rice-fallow mono-cropping. Soils are highly suitable (S1) for growing sunflower while moderately suitable (S2) for growing chilli, mustard and potato crops. The grid-wise georeferenced soil data information generated in this study will help in periodic monitoring of soil quality in spatio-temporal dimensions for devising location specific soil health managements in the Island. The methodology used in estimating soil quality index and crop specific soil suitability analysis in spatial format will help in replicating such studies in other such coastal Islands of Indian Sub-continent.

The coastal landuse and land cover features in the South West coast of Kanyakumari are dynamically regulated due to marine and terrestrial processes and often controlling by natural and anthropogenic activities. The primary objective of this study is to estimate the decadal changes and their transformations of landuse and land cover (LULC) features under Level II category of USGS-LULC Classification System using Landsat ETM+ and TM images using Maximum Likelihood Classifier (MLC) algorithm for the period 2000–2011. The classified LULC features are categorized as beachface land cover, cultivable lands, plantation and shrub vegetation, fallow land, barren land, settlements and built-ups, water bodies, and mining area, etc. The geo-database is prepared for LULC feature class with an attributes of name, location, area and spatial distribution, etc. It shows the larger area in beachface land cover (sandy beaches, foredunes, uplands, Teri dunes (laterite) and associated nearshore landforms), plantations, cultivable lands, fallows, and barren lands are converted into built-ups and it increases more than twice in the period of 10 years. Using GIS techniques, the analysis of change detection matrix reveals that the total area of 45.90 km2 in different LULC features periodically shifted or transformed from one state to another one or more states, i.e. the beachface land cover area of 1.24 km2 is encroached for built-ups and 0.63 km2 for placer mining during the decade. Meanwhile, the area of 0.21 km2 in this cover is transformed into wetlands and saltwater bodies. During the past decade, the expansion of area in the built-ups and settlements are directly proportional to the growth of population, which produces severe threat to the coastal resources. Accuracy assessment of classified images shows the overall accuracy is estimated as 81.16% and 77.52% and overall Kappa coeffient statistical values of 0.83 and 0.76 for the year 2000 and 2011 respectively. Ground truth verification of the extracted LULC features performed using 120 samples (10 samples per class) reveals that the accuracy of classified features is 89%. This indicates the acceptable accuracy of the classified LULC features for landuse and land cover change studies. The geodatabase of LULC features is used as primary source for sustainable land resource management in the coastal region.

This study aimed to model deforestation susceptibility in forest ecosystem of Rudraprayag district, India. For this purpose, site-specific physical (slope angle, slope aspect, altitude, annual average rainfall, soil texture, soil depth), and anthropogenic (population distribution, distance from road, distance from settlement, proximity to agricultural land) deforestation conditioning factors were chosen. Landsat TM and OLI images for 1990 and 2015 were utilized to evaluate the changes in forest cover. The frequency ratio model was used for deforestation susceptibility mapping. The extent of deforestation was examined by overlaying forest fragmentation map and deforestation susceptibility map. The results showed that about 112.5km 2 forest area has been deforested over the last 25years. Of the total existing forest, nearly 10% area falls under very high, 17% under high and 30% under moderate deforestation susceptibility categories. Patch, edge and perforated have influenced high (64%) and very high (81%) deforestation susceptibility zones. The integrated methodology involving frequency ratio model, fragmentation approach and remote sensing and GIS techniques has proved useful in analyzing deforestation susceptibility and identifying its causative factors. Thus, the methodology adopted in this study can best be utilized for effective planning and management of forest ecosystem., (Copyright © 2018 Elsevier B.V. All rights reserved.)