Correlations between discharge and meteorological parameters and runoff forecasting from a highly glacierized Himalayan basin

Abstract

To assess the predictive significance of meteorological parameters for forecasting discharge from the Dokriani Glacier basin in the Himalayan region, discharge autocorrelation and correlations between discharge and meteorological factors were investigated on a monthly and a seasonal basis. Changes in correlations between discharge and meteorological variables, lagged by 0–3 days, were determined. Discharge autocorrelation was found to be very high for each individual summer month and for the melt season as a whole. This suggests that a substantial meltwater storage in the glacier, which results in a delayed response of runoff, and therefore discharge, from the highly glacierized basins is very much dependent on the previous day's discharge. A comparison of correlations between discharge and temperature, and discharge and precipitation shows that temperature has a better correlation with discharge during June and September, while precipitation has good correlation with discharge in July and August. Variations in the physical features of the glacier, weather conditions, and precipitation and its distribution with time over the basin account for changes in correlations. To forecast the runoff from the Dokriani Glacier basin, multiple linear regression equations were developed separately for each month and for the whole melt season. A better forecast was obtained using the seasonal regression equation. A comparison of correlations for the Dokriani Glacier with those for the Z'mutt Glacier basin, Switzerland, illustrates that, for both basins, the previous day's discharge (Q_i-1) shows maximum autocorrelation throughout the melt period. Whereas a good correlation between discharge and temperature was observed for the Z'mutt Glacier basin for the whole melt period, for the Dokriani Glacier basin it was strong at the beginning and end of the ablation season. Runoff delaying behaviour in the Dokriani Glacier basin is found more prominent than in the Z'mutt Glacier basin early in the melt season. Water storage appears to be less significant in the Dokriani Glacier than in the Z'mutt Glacier towards the end of the ablation season. The strength of correlation between discharge and precipitation is higher for the Dokriani Glacier basin than for the Z'mutt Glacier basin. This is due to higher rainfall in the Dokriani Glacier basin. In general, for both glacier basins, maximum correlation is found between discharge and precipitation on the same day.     

Landscape level analysis of disturbance regimes in protected areas of Rajasthan,India

There is an urgent need to identify the human influence on landscape as disturbance regimes was realized for prioritization of the protected areas. The present study has attempted to describe the landscape level assessment of fragmentation and disturbance index in protected areas of Rajasthan using remote sensing and GIS techniques. Geospatial analysis of disturbance regimes indicates 61.75% of the total PAs are under moderate disturbance index followed by 28.64% and 9.61% under low and high respectively. Among the 28 protected areas- National Chambal WLS, Jaisamand WLS, Kumbhalgarh WLS, Sawai Man Singh WLS, Kailadevi WLS and Bandh Baratha WLS are representing high level of disturbance. The present study has emphasized the moderate to low disturbance regimes in protected areas, which infer low biotic pressure and conservation effectiveness of PA network in Rajasthan. The spatial information generated on PAs is of valuable use for forest management and developing conservation strategies.     

Settlement relocations in the char-lands of Padma River basin in Ganges delta, Bangladesh

Bangladesh has a unique hydro-geological setting and deltaic floodplain which is jointly formed by the deposition of the Ganges (Padma), Brahmaputra (Jamuna) and Meghna River. The physical characteristics of the geographic location, river morphology and the monsoon climate render Bangladesh highly vulnerable to natural disasters, primarily, floods and cyclones. River flooding has exerted a great impact on the culture and socioeconomic activities. The char people and their settlements in the Padma River channel are under threat due to floods and associated river bank erosion. The excess of water happens during the monsoon season because of widespread flooding that damages char-land settlements, agricultural crops, infrastructure and communication networks. Purba Khas Bandarkhola Mouza of Char-Janajat is largely affected by annual floods, and as a result the char people are displaced frequently from one place to another within and/or outside the char. The dwellers can return to the native char when new land emerges in the river channel after floods. This study has revealed that the displacement of char settlement takes place in almost every 3–5a at Purba Khas Bandarkhola Mouza of Char-Janajat. Our findings shed light on the char flood disaster management and social adaptation plan for settlement development of char livelihood in the Padma River basin in the Ganges delta of Bangladesh.     

Geochemical Modelling of Fluoride Concentration in Hard Rock Terrain of Madhya Pradesh, India

The aim of the present study is to locate and decipher the groundwater quality,types,and hydrogeochemical reactions,which are responsible for elevated concentration of fluoride in the Chhindwara district in Madhya Pradesh,India.Groundwater samples,quality data and other ancillary information were collected for 26 villages in the Chhindwara District,M.P.India during May 2006.The saturation index was computed for the selected samples in the region,which suggest that generally most of the minerals are saturated with respect to water.The concentration of fluoride in the region varies from 0.6 to 4.74 mg/l,which is much higher as per the national and international water quality standards.The study also reveals that the fluoride bearing rock formations are the main source of the higher concentration of fluoride in groundwater along with the conjuncture of land use change.Moreover,the area is a hard rock terrain and consists of fractured granites and amygdaloidal and highly jointed compact basalt acting as good aquifer,which is probably enriching the high content of fluoride in groundwater.High concentration of fluoride is found in deeper level of groundwater and it is possible due to rock-water interaction,which requires further detailed investigation.The highly alkaline conditions indicate fluorite dissolution,which works as a major process for higher concentration of fluoride in the study area.The results of this study will ultimately help in the identification of risk areas and taking measures to mitigate negative impacts related to fluoride pollution and toxicity.     

Ichnofossils from the Miocene Middle Bhuban Formation, Mizoram,Northeast India and their Paleoenvironmental Significance

An ichnofossil assemblage is preserved in sediments of the Middle Bhuban Formation,Surma Group,of Miocene age from the Durtlang and Chanmari sections,Aizawl district,Mizoram,northeastern India.The studied sections comprise a thick,bioturbated and thinly bedded sandstone–silty shale facies.The preserved ichnofossils show high density and low diversity with the assemblage represented by feeding and resting traces,i.e.,Psilonichnus upsilon Frey et al.,1984,Ophiomorpha isp.,Teichichnus spiralis Mikulá.1990,Skolithos isp.,Palaeophycus isp.,and other horizontal burrows.Sedimentary structures associated with these traces are mainly cross bedding,flaser bedding and slump structures.Considering the distribution of the Psilonichnus ichnogenus across an integrated ichnological–sedimentological framework,the stratigraphic interval of the Middle Bhuban Formation,in which they occur,are interpreted to have been deposited under a shallow,marginal-marine channel complex dominated by tidal channels developed in quiet,brackish-water portions of a delta plain.