Octeber, 2011

Octeber, 2011   ||  Volume 15 No.4


Studies on Land Use/Land Cover and change detection from parts of South West Godavari District, A.P – Using Remote Sensing and GIS Techniques

N.C.Anil, G.Jai Sankar, M. Jagannadha Rao*, I.V.R.K.V.Prasad and U.Sailaja

Dept.of Geo-Engineering, Andhra University, Visakhapatnam-530 003.
*Delta Studies, Andhra University, Visakhapatnam-530 003.

Land use/ land cover is an important component in understanding the interactions of the human activities with the environment and thus it is necessary to monitor and detect the changes to maintain a sustainable environment. In this paper an attempt has been made to study the changes in land use and land cover of southern part of West Godavari district. The study was carried out through Remote Sensing and GIS approach using SOI toposheets, Landsat imagery of 2000 and IRS-1D-LISS-III 2010. The land use/land cover classification was performed based on the Survey of India toposheets and Satellite imageries. GIS software is used to prepare the thematic maps and ground truth observations were also performed to check the accuracy of the classification. The present study has brought out that the aquaculture tanks have been decreased from 33.02% to 25.66% during 2000-2010 with a net decrease of 7.34%. Agriculture was also decreased from 43.32% to 37.75% with a net decrease of 5.56% during 2000-2010. The reasons for this decrease have been discussed. However, some plantations mixed with crops, fallow lands and settlements have shown considerable increase. The areas under natural streams/ rivulets, mangroves etc have shown no significant change and can be considered as a positive sign for sustainable development. Though there are some changes detected in landuse/land cover analysis of the period 2000-2010, it does not indicate any significant environmental impact on the study area. However, it is necessary to closely monitor the landuse/land cover changes for maintaining a sustainable environment..


Integrated approach using remote sensing & GIS for assessment of groundwater situation in parts of Chandrapur and Gadchiroli Districts of Maharashtra
Abhay M. Varade1, Priyanka Wath1, Kartik Dongre2 Y.D. Khare3 and Hemant Khandare4
1 PG Department of Geology, RTM Nagpur University, Amravati Road, Nagpur (MS) – 440001
2 Central Ground Water Board, Central Region, Nagpur- 440001
3 Retired Scientist, Maharashtra Remote Sensing Application Agency (MRSAC) Nagpur
4 MG College, Department of Geology, Armori
Correspondence: am_varade@yahoo.com

The present work deals with the assessment of groundwater potential zones in parts of Chandrapur and Gadchiroli districts of Maharashtra based on remote sensing and GIS approach, in which, the IRS-P6 LISS III geo-coded satellite data (21 April, 2006) and the Survey of India toposheet No. 55 P/14 on 1:50,000 scale were used. In the process of assessment of groundwater in the area, different thematic maps on lithology, lineaments, geomorphology and land use/land cover were prepared and assigned with differential weightage values as per their groundwater recharge and storage characteristics. Accordingly, the Groundwater Potential Map (GWP) for the study area was derived in the GIS environment by integrating all the thematic maps and considering their respective weightage values. Finally, the study area was classified into five zones of groundwater potentials i.e. excellent, very good, good, poor- moderate and poor.
In order to ascertain the validity of the derived GWP map, a field validation was carried out in the post-monsoon season of November, 2007. The well inventory study revealed that the GWP map derived through integrated approach using remote sensing and GIS techniques exhibits a good correlation with the actual groundwater scenario in the area. The study significantly demonstrates that the integration of thematic maps derived by using remote sensing technique in conjunction with collateral data in GIS environment is immensely helpful in delineating the groundwater potential zones at a micro-level.

Rainfall, runoff and sediment transport from a forested Lesser Himalayan watershed in Himachal Pradesh

Omvir Singh
Department of Geography
Kurukshetra University, Kurukshetra-136119, Haryana
Email: ovshome@yahoo.com;ovshome@gmail.com

Sediment transfer from continents to oceans via rivers is one of the most important processes. The amount of sediment transported from a watershed system is an indicator of the rate of erosion or the soil loss. In the present study, the long-term annual, seasonal, monthly and diurnal variations in sediment transport have been studied at the outlet (concentration point) of Tirthan watershed using the monitored data during 1981-2004. The sediment transport at the outlet of watershed is a function of rainfall and runoff occurring over the watershed area. A temporal and spatial variation in the amount of rainfall and runoff clearly exhibits annual, seasonal, monthly and diurnal variation in the sediment generation response behaviour. The higher concentration of rainfall depths exceeding 5 mm or more with significant variability could result in generation of more sediment fluxes. Both sediment concentration and load have been found to be the highest in the month of July followed by August and nearly 67% of the total sediment load has been transported in these two months. The peak of sediment load in July and August indicates that materials weathered during the dry season get mobilized during this period. Sediment load for the entire study period is computed as 454 t km-2 yr-1. Sediment yield from the watershed was lower as compared to the average sedimentation rate of the north Indian reservoirs. Availability of good forest cover (56%) within the watershed system may be attributed to low sediment transport rates from this watershed. The lower sedimentation rate from the watershed will enhance the operational efficiency of hydro-power projects to be built or already constructed in the Tirthan watershed system.  

Geophysical investigation for groundwater exploration in Lakshadweep Islands – A case study
N.B. Narasimha Prasad
Centre for Water Resources Development and Management,
Kozhikode 673571, Kerala State, India
E-mail: nbnprasad@hotmail.com

One of the main problems experienced by the islanders of Lakshadweep is associated with the availability of fresh water for drinking purpose. The scarcity of fresh water is due to the peculiar hydrologic, geologic, geomorphic and demographic features. Proper understanding of the groundwater condition, in terms of availability, distribution and quality, is very important to meet the increasing demand and also to formulate future planning and development of water resources. However there is very limited data / information available with regard to hydrogeological aspects of Lakshadweep. It is in this context; this study has been carried out. Geophysical investigation, using electrical resistivity method, is employed to locate potential zones of ground water in Andrott Island, one of the 10 inhabited islands in Lakshadweep. The data has been interpreted with the help of computer-aided techniques and presented in the form of spatial maps. The details of sub-surface lithology, as observed from the nearby existing dugwells and the water quality of the surrounding wells have also been considered during the interpretation of resistivity data.