The research questions

• Rapid surface and groundwater development throughout the Krishna basin has significantly reduced flows reaching the ocean, effectively "closing" the basin. Traditional water users like agriculture face increasing competition from other potentially higher-value uses: hydropower generation, industrial and domestic needs.
• What is the optimum inter-sectoral allocation in a multipurpose project in a water scarce basin?
• What are the economic and social costs and benefits of water in its different uses in the basin?
• What are the economic and social costs of likely water re-allocation in the long term, and in particular in low allocation years?
• What technical and institutional developments are required to embed these into an adaptive framework for long term sustainable management?

Objectives

To develop an integrative framework for the formulation and evaluation of water allocation strategies in three sub-basins of the Krishna River Basin, and within each state. The objective of understanding and advising on inter-state water allocation has been downgraded due to political hostility from the states.

Methods

• Three representative sub-basins have been selected in each state
  • Malaprabha (Karnataka)
  • Upper Bhima (Maharshtra)
  • Musi (Andhra Pradesh)
• The three sub-basins represent most of the issues experienced in the nine sub-basins of Krishna. Musi sub-basin represents intra-sectoral water allocation issues in a semiarid zone including groundwater, tanks, urban water demand, medium and major irrigation projects and waste water.
• Water balance and historical use trends: The purposes of the hydrologic analysis and modeling are to;
  1. Identify the most important components of the water balance
  2. Identify key uncertainties in the balance to guide further data collection activities
  3. Evaluate the hydrologic implications of different water allocation scenarios.
• Remote sensing is being used to improve the accuracy and spatial coverage of evapo-transpiration and rainfall components of the water balance. The SEBAL procedure and publicly available MODIS satellite data are being used to estimate the evapo-transpiration. Rainfall data can be spatially interpolated from cold cloud cover duration using AVHRR and also from TRMM satellite data. Land use, with a focus on sources of irrigated area, is also being determined using fine and coarse resolution satellite imagery to relate evapo-transpiration to human activities. The source wise irrigated area mapping can provide the estimates of groundwater irrigated area that is being used in conjunction with ground truth survey of the field, to estimate the ground water usage in the basin. In addition, the ground water usage may be estimated from irrigation census data, and irrigation diversions will be quantified indirectly using mass balance from discharge and reservoir storage measurements.
• Hydrologic analysis and stream flow simulation: Rainfall data are available from the past 100 years but synthetic stream flow data will need to be generated for part of this period. Suitable data interpolation techniques including catchment similarity relations and hydrologic modeling will be used to forecast the stream flow. IWMI is currently undertaking research in this direction and these results can be utilized for this project. Additional modeling analysis will be needed to in-fill missing runoff data. This will be carried out in three selected sub-basins.
• Water allocation modeling: The main aim of allocation modeling in the selected sub-basins is to develop a generic process for modeling alternative allocation scenarios. A two-phase approach is being used. An initial exploratory analysis using a simple model such as WEAP to explore and understand the relations between the major water uses in the Krishna basin. The second stage involves the application of the Resource Allocation Model (REALM). The REALM is a well-proven tool to aid water resource planning and management in both urban and rural water supply systems.
• Development of allocation scenarios in the selected sub-basin within each riparian state: Simulation of new scenarios will be carried out based on various cropping patterns, climate change (wet, normal and dry climates), waste water re-use, urban requirements, future power requirements, etc. The implications of these scenarios on growing food demands (at least one crop per season to the farmers) and their environmental and socio-economic implications can then be assessed. The scenarios will also be analyzed at various reliability levels needed to meet priority human demands (drinking water, food security, etc.).
• Econometric modeling and integration: The economic modeling framework aims to provide insight into the potential water productivity gains from changes in allocated volumes as well as into gains from waste water treatment. This analysis will be integrated in the water allocation model to be able to assess the gains in water productivity of the alternative allocation scenarios the water allocation model assesses.

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