Temporal change detection in river courses and flood plains in an arid environment through satellite remote sensing

Temporal changes in ephemeral river courses and associated flood plains, which could not be detected by Landsat MSS due to its poor spatial resolution of 80m, have been identified and mapped within 10% accuracy by Landsat TM False colour composite because of its higher spectral and spatial resolution of 30 m. Over a period of 28 years (1958–86) the river courses widened upto 1.8 times through bank erosion due to the recurring flash floods. The flash floods have also caused morphological, soil fertility and landuse changes in the associated flood plains, which could also be monitored by the Landsat TM.     

Understanding the hydrological system dynamics of a glaciated alpine catchment in the Himalayan region using the J2000 hydrological model

This paper provides the results of hydrological modelling in a mesoscale glaciated alpine catchment of the Himalayan region. In the context of global climate change, the hydrological regime of an alpine mountain is likely to be affected, which might produce serious implications for downstream water availability. The main objective of this study was to understand the hydrological system dynamics of a glaciated catchment, the Dudh Kosi River basin, in Nepal, using the J2000 hydrological model and thereby understand how the rise in air temperature will affect the hydrological processes. The model is able to reproduce the overall hydrological dynamics quite well with an efficiency result of Nash–Sutcliffe (0.85), logarithm Nash–Sutcliffe (0.93) and coefficient of determination (0.85) for the study period. The average contribution from glacier areas to total streamflow is estimated to be 17%, and snowmelt (other than from glacier areas) accounts for another 17%. This indicates the significance of the snow and glacier runoff in the Himalayan region. The hypothetical rise in temperature scenarios at a rate of +2 and +4 °C indicated that the snowmelt process might be largely affected. An increase in snowmelt volume is noted during the premonsoon period, whereas the contribution during the monsoon season is significantly decreased. This occurs mainly because the rise in temperature will shift the snowline up to areas of higher altitude and thereby reduce the snow storage capacity of the basin. This indicates that the region is particularly vulnerable to global climate change and the associated risk of decreasing water availability to downstream areas. Under the assumed warming scenarios, it is likely that in the future, the river might shift from a ‘melt‐dominated river’ to a ‘rain‐dominated river’. The J2000 model should be considered a promising tool to better understand the hydrological dynamics in alpine mountain catchments of the Himalayan region. This understanding will be quite useful for further analysis of ‘what‐if scenarios’ in the context of global climate and land‐use changes and ultimately for sustainable Integrated Water Resources Management in the Himalayan region. Copyright © 2012 John Wiley & Sons, Ltd.     

Temporal change of glaciers area and geomorphometric parameters in Parbati valley,Himachal Pradesh,India

Temporal change in the glacier coverage is analyzed for the period between 1962 and 2003 in Parbati valley, Himachal Pradesh. It is observed that the total glacier cover has been decreased by 17% ranging between 8 and 100% for individual glacier. The pattern of de-glaciation shows a high degree of shrinkage in outer zone of Parbati valley, while least shrinkage is observed in the inner valley. The present study is conducted to establish relationship between glacio-geomorphic parameters and glaciers shrinkage pattern to predict the future glacier cover in warming scenario. A systematic change is observed for glacio-geomorphic parameters associated with temporal change in glacier cover. It is observed that mean and minimum elevation, slope, relief and duration of insolation have changed substantially. Maximum elevation, plan/profile curvatures and aspect have shown less change from 1962 to 2003. A correlation matrix between glacio-geomorphic parameters for glaciers between 1962 and 2003 shows that the recent glaciers are much more controlled by terrain characteristics than that in the recent past.     

Application of remote sensing data in characterization and mapping of soil resources for watershed planning in arid Western Rajasthan

Visual interpretation of IRS-L1SS-II (January, 1995) FCC (1:50,000 scale) of spectral bands 2, 3 and 4 was carried out for the identification and mapping of major physiographic units in an arid watershed of Jodhpur district (Rajasthan). Based on image characteristics and field traverses, seven major physiographic units identified are (1) hills (2) pediments, flat to undulating (3) buried pediments, moderately deep to deep, coarse textured (4) buried pediment, shallow to moderately deep and deep, medium to fine textured, saline (5) older alluvial plains, deep and very deep, coarse textured (6) younger alluvial plains, deep to very deep, very coarse textured and (7) dune complexes. Based on physiographicvariatton and soil or site characteristics such as texture, depth, slope, erosion and underneath substrata, 41 soil mapping units were identified and mapped. Final physiography, soil, slope, drainage and landuse maps were prepared on 1:5,000 scale. Taxonomically, the soils of the watershed were classified as Para-Lithic Torriorthents, coarse-loamy, Lithic/Typic Haplocambids, fine-loamy, Lithic/Typic Haplosalids and Typic Torrifluvents and Typic Torripsamments. Land suitability for various mapping units in the watershed have been assessed on the basis of soil physico-chemical characteristics.     

Satellite remote sensing for detecting the temporal changes in the grazing lands

Traditional grazing lands in the Indian arid zone can be identified and mapped, reliably and reasonably within ±10% accuracy, through Landsat TM false colour composite of bands 2,3,4. Comparative study of Landsat TM and the Survey of India topographical maps revealed reduction in the areal extent of the grazing lands in the Jodhpur district up to 9 to 30% over a period of 28 years, between 1958 and 1986, due to the human activity like cultivation and urbanisation resulting in the desertification of the adjoining agriculturallands.     

Location-allocation modeling for emergency evacuation planning with GIS and remote sensing: A case study of Northeast Bangladesh

This work developed models to identify optimal spatial distribution of emergency evacuation centers(EECs) such as schools, colleges, hospitals, and fire stations to improve flood emergency planning in the Sylhet region of northeastern Bangladesh.The use of location-allocation models(LAMs) for evacuation in regard to flood victims is essential to minimize disaster risk.In the first step, flood susceptibility maps were developed using machine learning models(MLMs), including: Levenberg–Marquardt back propagation(LM-BP) neural network and decision trees(DT) and multi-criteria decision making(MCDM) method.Performance of the MLMs and MCDM techniques were assessed considering the area under the receiver operating characteristic(AUROC) curve.Mathematical approaches in a geographic information system(GIS) for four well-known LAM problems affecting emergency rescue time are proposed: maximal covering location problem(MCLP), the maximize attendance(MA), p-median problem(PMP), and the location set covering problem(LSCP).The results showed that existing EECs were not optimally distributed, and that some areas were not adequately served by EECs(i.e., not all demand points could be reached within a 60-min travel time).We concluded that the proposed models can be used to improve planning of the distribution of EECs, and that application of the models could contribute to reducing human casualties, property losses, and improve emergency operation.     

Impact assessment of industrial effluent of arid soils by using satellite imageries

Visual interpretation ofIRS-LISS-II (1:50,000 Scale) FCC, band 2, 3 and 4 was carried out for the Industrial effluence assessment on soils (21900 ha) along the Bandi river course in Pali district of arid Rajasthan. Very severe (4378 ha), severe (3427 ha), moderate (5856 ha) and slight (1388 ha) categories of anthropogenic salt affected soils with the varied image characteristics in conjunction with ground truth Have been identified and delineated from satellite imagery. The morphological and physico-chemical characteristics revealed that very severe category soil has thick salt crust dominantly in light gray color at surface, manifestation of strong sub-angular to angular blocky structure, extra-ordinary hardness, high ECe, SAR and ESP but low pHs. Severe category soils have light brownish gray colour at surface, manifestation of strong angular to columnar structure, high Ece, pHs, SAR and ESP but slightly lower than very severe category.Moderate category soils have light brownish gray colour at surface, moderate to strong manifestation of prismatic structure, low ECe but high pHs, moderate to high SAR and ESP.Slight category soils have pale brown colour and hard crust at surface, moderate hardness with the tendency to form weak prismatic structure in subsoil, low ECe (<4dSm^-) but moderate pHs. The cations and anaions in saturation extract was in the order of Na⁺>Ca⁺⁺ > Mg⁺⁺ > K⁺ and Cl^- > SO₄ ^-- > HCO₃ ^-- > CO₃ ^--, respectively and salinity/sodicity was Sodium-Chloride-Sulfate type. Dynamics of salt accumulation, available nutrient status and amelioration measures required for their reclamation and improvement has been discussed in this paper.     

Assessment of spatial transferability of process‐based hydrological model parameters in two neighbouring catchments in the Himalayan Region

Estimating the hydrological regime of ungauged catchments in the Himalayan region is challenging due to a lack of sufficient monitoring stations. In this paper, the spatial transferability of the model parameters of the process‐oriented J2000 hydrological model was investigated in 2 glaciated subcatchments of the Koshi river basin in eastern Nepal. The catchments have a high degree of similarity with respect to their static landscape features. The model was first calibrated (1986–1991) and validated (1992–1997) in the Dudh Koshi subcatchment. The calibrated and validated model parameters were then transferred to the nearby Tamor catchment (2001–2009). Sensitivity and uncertainty analyses were carried out for both subcatchments to discover the sensitivity range of the parameters in the two catchments. The model represented the overall hydrograph well in both subcatchments, including baseflow, rising and falling limbs; however, the peak flows were underestimated. The efficiency results according to both Nash–Sutcliffe (ENS) and the coefficient of determination (r²) were above 0.84 in both catchments (1986–1997 in Dudh Koshi and 2001–2009 in Tamor). The ranking of the parameters in respect to their sensitivity matched well for both catchments while taking ENS and log Nash–Sutcliffe (LNS) efficiencies into account. However, there were some differences in sensitivity to ENS and LNS for moderately and less‐sensitive parameters, although the majority (13 out of 16 for ENS and 16 out of 16 for LNS) had a sensitivity response in a similar range. The generalized uncertainty likelihood estimation results suggest that the parameter uncertainty are most of the time within the range and the ensemble mean matches very good (ENS: 0.84) with observed discharge. The results indicate that transfer of the J2000 parameters to a neighbouring catchment in the Himalayan region with similar physiographic landscape characteristics is viable. This indicates the possibility of applying a calibrated process‐based J2000 model to other ungauged catchments in the Himalayan region, which could provide important insights into the hydrological system dynamics and provide much needed information to support water resources planning and management.     

Determinants of agricultural commercialization and mechanization in the hinterland of a city in Nepal

In view of the significance of agricultural commercialization for rural development, this study analyzed factors determining agricultural commercialization and mechanization in the hinterland of an urban centre in Morang district, Nepal. Information needed for the study was collected through a questionnaire survey, covering 120 farm households, and group discussion and key informant interviews. The regression analysis of determinants of agricultural commercialization revealed four significant variables, namely, the amount of inorganic fertilizer used, area under tractor-ploughing, area under pump-set irrigation and landholding size. The predicted R value of 0.87, R square of 0.75, and adjusted R square of 0.75 indicate the high explanatory power of the model as a whole. The regression model related to the area under pump-set irrigation predicted the degree of agricultural commercialization and the distance from the city as significantly influencing factors, with a predicted R value of 0.79, R square of 0.63, and adjusted R square of 0.62. The analysis of determinants of the area under tractor-ploughing found only the degree of commercialization as a significantly influencing factor, with a predicted R value of 0.77, R square of 0.59, and adjusted R square of 0.58. In both instances of farm mechanization, the degree of commercialization is the most influential factor, indicating the significant role of mechanization in agricultural commercialization. The major policy implications of the findings of the study are outlined.