Scientists predict that the long-term impacts of climate change and watershed development (WSD) on water security - in individual catchments and in the whole of the basins - will be severe in many river basins worldwide, including the Krishna and the Murray-Darling basins. Already the Krishna river basin is closing as a result of the combined impacts of vast irrigation developments over the past 50 years and extensive WSD programs promoted by the Indian Government. By the year 2100 some predict that India will experience a 3-5oC increase in average temperature and the Krishna basin will experience a 20% decline in precipitation. Accordingly, runoff in the Krishna basin would decline 30-50%. Thus achieving the desired level of agricultural growth will be challenging. This project will assess the potential impacts of WSD and climate change on the long-term water security for agriculture in the Krishna river basin and compare the findings with the forecast impacts and adaptation strategies in the Murray-Darling basin. The assessment will help to ascertain how well these strategies can support future food production and the concomitant effects they may have on farmer’s livelihoods.
This project commenced in April 2010 and an inception workshop was held one month later in Melbourne. This workshop was attended by all the participants in the project, along with representatives of the other ACIAR cluster funded projects in India. In this workshop a detailed project plan was developed and methods for integrating the various components of this project together, both internally and externally with other related ACIAR projects were established. In addition, a project collaboration strategy was discussed that provides for the direct communication between interested parties on methodology, data sharing and publication issues.
The main aim in this project is to assess the combined impacts of watershed development and climate change adaptation strategies on the long term water security for agriculture in the Krishna river basin and compare them with the forecast of impacts and adaptation strategies in the Murray-Darling basin. This project is designed to operate at two scales - sub-basin and whole-of-basin.
Initially, an investigation of the historical changes in key climatic inputs such as temperature, relative humidity and rainfall, was undertaken in the study area. It was found that no substantial change in the southwest monsoon rainfall occurred during the last 60 years. However, over that period the number of extreme 1-day rainfall and heavy rainfall events (>70 mm/day) were found to increase significantly, while low rainfall events (2.5mm-10mm) did not show a statistically significant trend. The analysis of average annual temperature shows a significant increase (0.08 C/decade) in the Krishna basin. A similar analysis in the Murray-Darling basin shows that a temperature increases of 0.9 C since 1950.
Three climate simulations corresponding to the IPCC-SRES A1B scenario were downscaled for the period 1961-2098 using “Providing REgional Climates for Impact Studies” (PRECIS) regional climate modelling system. These simulations were based on three versions of the HadCM3 global climate model which showed realistic results for the Indian summer monsoon. These global simulation results were extracted from the program on Quantifying Uncertainty in Model Predictions (QUMP). The simulations predict a 2% to 6% rise in the rainfall by 2020 compared to the model baseline (1961-90). However, rainfall is predicted to increase further towards the middle of the century. The model also predicts a mean annual temperature rise of around 2.50 C by the mid 2080s.
Remote sensing has been used to map land use, dynamic vegetation information, surface water reservoirs and evapotranspiration. This information will be integrated into the hydrologic modelling framework in order to constrain the models’ parameters, to provide inputs and to calibrate and verify model outputs. This information is collected and analyzed at two different scales -medium-resolution land use and evapotranspiration products over the whole Krishna River Basin and high-resolution products in the Musi catchment. In addition, a field experiment was conducted in the Musi catchment to measure high-quality spectral libraries using multispectral radiometers in the field. These will be combined with the satellite images to better understand the region-specific features of the crop species and their spectral characteristics.
Detailed data collection is currently being undertaken to characterise the key hydrological processes. The required variables (daily rainfall, maximum and minimum temperatures, wind speed, solar radiation and relative humidity) have been obtained from the Indian Meteorological Department stations. Collection of watershed structures and groundwater flow data is currently in progress.
The lumped hydrological model SimHYD was used to undertake a preliminary assessment of climate change and watershed development impacts on the hydrology of the region. It was found that the impacts are not spatially uniform across the basin. The development of the distributed model SWAT for the catchments is currently being undertaken.
At both central and state levels we have undertaken a mapping of the institutions and the identification of the programmes and policies on water that are currently promoted in the basin. Organograms have been developed which allowed the preparation of an initial database of various policies at the national level (including the National Water Policy and the National Water Mission) and at the State level for Maharashtra, Andhra Pradesh and Karnataka. This review forms the basis to understand the overarching framework that governs water use in the basin and to identify the relevant stakeholders at all levels in the basin. This review together with the study of socio-economic aspects and water utilisation patterns at sub-basin and basin levels were undertaken in preparation for the development of adaptation scenarios and concomitant adaptation responses.
Overall, the work undertaken in this first year of the project largely provides the basis for subsequent project activities. Once the hydrological models are built, it should also be possible to evaluate the economic activities using cost effectiveness analysis and provide a real options tool to policy makers.
The aim in this report is to describe the activities undertaken in project LWR/2007/113, between July 2001 and June 2012. The progress achieved to date, is shown in relation to the project schedule as it was outlined in the original proposal. This report presents a brief overview of progress in each component of the project, followed by a several individual reports containing a more detailed description of activities and results achieved in various components of the project.
The main aim in this project is to assess the combined impacts of watershed development and climate change on the long term water security for agriculture in the Krishna river basin in India and compare them with the forecast of impacts and adaptation strategies in the Murray-Darling basin. The geographical focus of the project is the MUSI basin in the State of Andhra Pradesh, India. It should be noted that during the period covered in this report, ACIAR conducted the midterm review of the project in Hyderabad over two days in September 2012. The review involved a review of the scientific outcomes of the project combined with a plenary stakeholder workshop involving government and multiple community and non-government organisations.
There are five distinct research components to this project, each which is the specific responsibility a project partner. They are:
Modelling and analysis of climate change
Remote sensing of land use and evapotranspiration
Development of scenarios and adaptation responses
Analysis of surface and groundwater hydrology
Modelling catchment and river basin water allocation and security
Real Options and scenario analysis
At the present stage of the project timeline and consistent with the project schedule, work has progress primarily in the first three areas.
Modelling and analysis of climate change
Remote sensing and analysis of surface and groundwater hydrology
Development of scenarios and adaptation responses
The highlights of the retrospective climate analysis reveal that there has been no substantial change in the southwest monsoon rainfall, its onset and its duration during last 50-60 years in the Krishna basin. In the Musi catchment, seasonal rainfall was found to be increasing and monsoon season temperatures show a significant rise that is similar to the rest of the Krishna basin. The climate modelling to predict future climate in the region includes three climate scenarios selected from the IPCC-SRES A1B scenario which derives from three ensembles of the HadCM3 global climate model. Simulations from the downscaled climate model showed a 2% to 6% decline in precipitation in the period 2020/30, followed by an increase in rainfall towards the middle of the next century. Rainfall variability is expected to increase as this century progresses and rainfall deficient years are likely to be more severe. The mean annual temperature shows consistent upward changes in all the time slices (2030, 2050, 2080) leading to around 2.5C towards the end of this century
Historical Evapotranspiration (ET) in the Krishna basin was estimated by combining remotely sensed data and ground based meteorological data using modified Penman- Monteith approach with biometric specific canopy conductance determined from Normalised Difference Vegetation Index (NDVI) for the period from 1982 to 2001. ET was found to increase at a rate of approximately 9.4 mm/annum in the basin during this period.
Remote sensing was also used to classify land use in the MUSI catchment using an approach developed from a combination of the Australian-India Land Surface Parameterisation Experiment (AILSPEX-11), Land Surface Water Index (LSWI) and NDVI techniques. The analysis allowed the classification of paddy and non-paddy rice fields in the catchment.
A hydrological analysis was undertaken to assess the hydrological and meteorological trends and anthropogenic changes that have occurred in different components of the water balance in the Himayat Sagar Catchment. It was found that there were no statistically significant trends in annual rainfall from 1980 to 2004, whereas there are clear declining trends over time in catchment outflow. The analysis of hydrologic impacts of climate change shows that there is a notable rise in average annual flows between 2011 and 2080 as a result of increased precipitation amount and high intensity precipitation events. This trend in annual flows is accompanied by a greater variability in runoff flows which occurs in all three climate scenarios. More importantly, increases in surface runoff follows a non-linear relationship with runoff increasing more than proportionally to increases in total precipitation.
Initial work in the groundwater component has focused on understanding and conceptualising the aquifer systems within the catchment. The results to date reveal that the groundwater flow system in the Musi sub-basin to be highly controlled by fracture intensity and weathering distribution. Groundwater development potential is shown to be directly proportional to the fracture intensity. Hydraulic analysis indicates that the Musi River is contributing to groundwater storage in the rainy season whilst during the remainder of the year groundwater drains into the river. Groundwater modelling and analysis was undertaken for the entire Musi catchment to quantity groundwater transfer between the groundwater and river interactions. The model calibration and validation are currently in progress.
An extensive consultation process has been carried out at three government and community levels -State and District Governments and Farmers - to elicit potential responses to future climate change. While this process has not yet been completed, it is observed that there is a clear gap in expectations between different stakeholders groups and government about climate adaptation responses. It is critically important that the adoption of any adaptation response(s) involves actions consistent with the expectations and capacity for adaptation by all tiers of affected stakeholders, and it is informed by factual evidence arising from the hydrologic and economic impacts of each response. The outcomes of this consultation process are the main consideration in the formulation of climate adaptation responses currently in progress. As a preparation for the economic tasks that will be completed later in this project, a number of issues confronting the long term estimation of the costs and value of water have been addressed.
The overarching aim of this project is to assess the combined impacts of watershed development and climate change on long-term water security in the Krishna Basin and to develop a Scenario Planning framework for generating and evaluating climate change adaptation responses. The project’s geographical focus is the Musi catchment in the State of Andhra Pradesh, India.
In this, the third year of the project, much of the remote sensing and hydrological work required to evaluate the impacts of climate change and watershed development has been completed. This work builds on and integrates the work on downscaling the global climate modelling work completed earlier in the project and lays the foundations for future work on allocation and economic modelling. The highlights from this year’s work include:
A new satellite based remote sensing algorithm calibrated and validated for the Krishna River Basin.
Calibration and evaluation of surface-groundwater models and preliminary evaluation of climate change impacts on the Musi catchment hydrology.
Climate change adaptation responses from stakeholders and government.
The methods needed to assess the economic impacts of adaptation policy prescriptions.
The remote sensing component of the project has largely been completed this year for the Musi catchment and mapping yearly land cover maps and spatially distributed evapotranspiration (ET) have been extended to the whole of the Krishna River Basin. In addition, monthly time series of ET maps from 1983 to 2000 were produced using remotely sensed imagery from the Advanced Very High Resolution Radiometer (AVHRR). It has been found that the basin-average ET has steadily increased at the mean annual rate of 5.00 mm/year/year in the Krishna River Basin between 1983 and 2001. This increase is mainly due to irrigation development and the resulting increase in plant biomass. An innovative algorithm was developed to map flooded rice paddies and applied to the whole of the Krishna River Basin to carry out a more accurate estimation of ET. This application found that conventional remote-sensing ET algorithms largely underestimate ET over flooded rice paddy areas during the growing season, leaving a large deficit in annual water balance. This rice paddy map can be used to update the basin-scale ET maps and to verify/validate the hydrological modelling over the Musi catchment.
The development of a combined surface-groundwater modelling capability is a critical element of this project that has occupied much of this year’s effort. The SWAT and MODFLOW models were fully calibrated and evaluated to determine the impacts of three climate scenarios selected from the HadCM3 global climate model (Q0, Q1, Q14) on surface and groundwater resources. The three variants of the model produced wide net variations in streamflows over the period 2011-2098 ranging from an average increase of 100% for climate scenario Q0 to 50% decrease for Q1 and 30% increase for Q14. All scenarios show an increase in flow variability in respect of the historical data. Evapotranspiration is predicted to increase by between 2% and 15% over the period analysed under all climate scenarios. The future impact of hydrologic structures under climate scenario Q0 is predicted to be greater in dry years due to a high rainfall-runoff elasticity of the Musi catchment. The preliminary groundwater analysis for the period 2011-2050 shows an average increase in recharge of 13% under the Q0 climate scenario, and declines of 30%-60% and 5% under scenarios Q1 and Q14, respectively.
The selection of adaptation responses to climate change scenarios forms the core of the project’s analytical framework. In this third year of the project, a second round of stakeholders and government consultations was conducted to define the final set of climate change adaptation responses. These consultations were focused on three districts of the Musi catchment (Nalgonda, Rangareddy and Mahabub Nagar). As expected, stakeholders held a wide range of views on how to adapt to future climate change. The various options were evaluated and ranked using a set of objective criteria. This process yielded five well defined adaptation responses that will be hydrologically and economically evaluated in the next stage of the project - changing cropping pattern, additional water storage capacity, increasing volume of groundwater extraction, improved efficiency and increasing farm tanks and ponds.
The economic component of this project is designed to evaluate the cost and performance of each adaptation response and the implementation time-sequence. It is linked to the hydrological elements in order to inform policy development. The economic analysis framework consists of a Cost-Effectiveness approach combined with Decision Analysis that takes account of the Real Options values of delaying or advancing adaptation responses. The framework is designed to overcome two main constraints that bedevil decision analysis over periods greater than 40-50 years - the selection of the discount rate and quantification of risks associated with optional implementation strategies.