Volume-1 :: Issue-3
Uncertainty of Streamflow Forecasting with the Climate Change Scenario in India
Streamflow and rainfall estimates have utmost importance to compute detailed water availability and hydrology for many sectors such as agriculture, water management, and food security. There are various models developed over the years for runoff estimation but among them only a few models incorporate climate change factors. Snowmelt and rainfall are the main sources of surface as well as groundwater resource and the main inputs in runoff models for estimation of streamflow. There are numerous factors which leads to climate change which intern affects the distribution on rainfall on spatial and temporal scales and the rate of melting of snows in the Himalayan region. Uncertainties in projected changes in the hydrological systems arise from internal variability in the climatic system, uncertainty about future greenhouse gas and aerosol emissions, the translations of these emissions into climate change by global climate models, and hydrological model uncertainty. Projections become less consistent between models as the spatial scale decreases. The uncertainty of climate model projections for freshwater assessments is often taken into account by using multi-model ensembles. The multi-model ensemble approach is, however, not a guarantee of reducing uncertainty in mathematical models. In recent years the floods have occurred due to high intensity rainfall occurred in a very short time, but in several cases the flooding has also occurred because the rainfall has fallen at times when all the storage systems have not been emptied after the previous rainfall. This is what we call coupled rainfall. There is currently no recommendation for how to take coupled rainfall account when applying the climate change scenario. It is estimated that such changes represent at a large scale, and cannot be applied to shorter temporal and smaller spatial scales. In areas where rainfall and runoff are very low (e.g., desert areas), small changes in runoff can lead to large percentage changes. In some regions, the sign of projected changes in runoff differs from recently observed trends. Moreover, in some areas with projected increases in runoff, different seasonal effects are expected, such as increased wet season runoff and decreased dry season runoff. Studies using results from fewer climate models can be considerably different from the other models.
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Estimation of Soil Loss from Watershed for Identifying High Risk Erosion Zones Using GIS
Chandra Sekhar Matli, Nimmy John
Soil loss from watersheds significantly influences the fertility soils and natural environment and hence it is a serious concern across the globe. Soil conservation is the top priority in watershed management though it is impractical to completely control soil erosion from all parts of watershed and hence achieve soil conservation. As controlling soil erosion in watersheds at micro level is difficult, broad measures which are economical and feasible are recommended for soil conservation. In order to plan suitable conservation techniques, it is essential to prioritize watersheds based on vulnerability to soil erosion. For identifying suitable soil conservation methods, it is necessary to consider critical erosion zones, threats to lives and property, socio-economic constraints and local challenges. Assessment of soil erosion is very important for arriving at the prioritization of watersheds for soil conservation. This paper reports the findings of the study carried out on Janagoan Mandal in Warangal District with hell of GIS techniques. Estimation of soil loss from the watershed is estimated using Universal Soil Loss Equation (USLE). Using the data available with various agencies, average annual erosion is estimated by developing GIS maps for six major watershed parameters. The watershed has been divided into sub watersheds and prioritization study is carried out considering factors that influence soil erosion. Using GIS tool and Universal Soil Loss Equation (USLE), the soil loss from the watershed is estimated and high risk zones are demarked. Soil loss from 80% of the watershed area is in the range of 0 – 200 tons/ha/year, while the high risk zones of erosion are about 12% of the area. Watershed management practices are recommended to reduce the soil loss from the high risk zones.
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Optimal Design and Analysis of Water Distribution Networking System using EPANET
Bipin Sahu, Ajai Singh
To satisfy the increasingly growing population’s water demand, it is necessary to provide adequate and consistent quantities of water across the planned pipeline network. The scarce water resources must be planned scientifically and proper water distribution network can play an important role in managing non-revenue urban and rural water management. In the present work, we have applied the EPANET model for analyzing the water distribution system for a small place in Ranchi, Jharkhand. The results showed that the pressures at all junctions and the flows at all pipes are sufficient to provide adequate water for the design network. The maximum pressure was observed to be 30.04 m and the flow was also quite reasonable for transporting the water to the consumers. The study demonstrated the application of EPANET for analyzing a water distribution system and should be used to check non-revenue urban and rural water management.
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Entropy Analysis of Seasonal Groundwater Level Fluctuations for Delhi and Haridwar Regions of India using GRACE Satellite Data
Shekhar Singh, Deepak Kumar
Groundwater monitoring and its spatio-temporal study require installation and management of ground-based observation wells on a large scale. The cost associated with such a study is generally high. An alternative to it is to use remote sensing data to manage groundwater resources in the least cost. There are only a few satellites which can provide gravity-based groundwater data. Gravity Recovery and Climate Experiment (GRACE) is a satellite which measures the change in gravity and is further used to study groundwater fluctuations. In the present study, groundwater fluctuations data (Product of GRACE satellite data) for Haridwar and Delhi region of India has been used to study the temporal and spatial variability using entropy theory. The temporal data from 2003 to 2016 has been used for both regions. The results suggested that the groundwater fluctuations are increasing in both regions of the study area. Results suggested that fluctuation of groundwater was high for the winter season of all years, but in the post-monsoon season, the fluctuation in between Delhi and Hardwar has been detected just about same Seasonal fluctuation in water level for both regions showed a maximum rise of 60 cm in water level and also maximum fall in the same range.
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Hydrological Inferences and Functions of Grasslands: An Indian Scenario
Murari Lal Gaur
Grasslands together with rangelands & pastoral scenery, forms about 40% of the global land surface, and remains an important ecosystem to offer livelihoods for more than 800 million people. They are active sink for about one-third of the global stock of carbon. The growing issues of climate change and water scarcity have added a new dimension to the values of such lands with a critical warning to appropriately understand their hydrological processes and water budget. Harnessing optimum productivity of bio-mass and water from such land parcels is a growing need to cater the upward feeding demands of India’s livestock (being largest in the world ~623 M of which at least 50 % depends upon open grazing on natural grasslands). Indian grasslands are still least understood and underestimated natural habitats where grazing-based livestock husbandry continuously influence the regional water economy. The rationale of this paper is revealing potential benefits and developmental prospects of Indian grasslands to facilitate their elementary role to regulate prevailing natural resources at watershed scales. It describes the interacting factors that indeed affect the hydrologic cycle under rangeland/pastureland conditions. The author has shared his own case studies and 20 years operational experiences while being actively engaged in planning, development and management of grasslands, wastelands, and degraded forest catchments in many parts of India. It also includes few outcomes from execution of soil & water conservation plans & measures controlling runoff and soil erosion to deliver better (quantitative & qualitative) biomass outputs from such lands. A substantial food for thought is provided for debating & devising a suitable component of water policy framework exclusively for such lands
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