Drought severely damages water and agricultural resources, and both hydrological and ecological responses are important for its understanding. First, precipitation deficit induces soil moisture deficiency and high plant water stress causing agricultural droughts. Second, hydrological drought characterized by deficit of river discharge and groundwater follows agricultural drought. However, contributions of vegetation dynamics to these processes at basin scale have not been quantified. To address this issue, we develop an eco-hydrological model that can calculate river discharge, groundwater, energy flux, and vegetation dynamics as diagnostic variables at basin scale within a distributed hydrological modeling framework. The model is applied to drought analysis in the Medjerda River basin. From model inputs and outputs, we calculate drought indices for different drought types. The model shows reliable accuracy in reproducing observed river discharge in long-term (19 year) simulation. Moreover, the drought index calculated from the model-estimated annual peak of leaf area index correlates well (correlation coefficient r 5 0.89) with the drought index from nationwide annual crop production, which demonstrates that the modeled leaf area index is capable of representing agricultural droughts related to historical food shortages. We show that vegetation dynamics have a more rapid response to meteorological droughts than river discharge and groundwater dynamics in the Medjerda basin because vegetation dynamics are sensitive to soil moisture in surface layers, whereas soil moisture in deeper layers strongly contributes to streamflow and groundwater level. Our modeling framework can contribute to analyze drought progress, although analyses for other climate conditions are needed.

[1] Drought in the Philippines has been monitored for agricultural and economic losses, but spatial and temporal characterization at the basin scale has not been quantified. The relationship between different drought types, and how these can be integrated into timely water-resource-management planning in the agriculture and water sector of the Pampanga River basin, were considered. Specifically, the objectives of this study are as follows: (1) to propose a standardized anomaly (SA) index for assessing different types of drought impacts at the basin scale; (2) to quantify vulnerability of the agriculture and water sectors using physically consistent hydrological parameters with temporal variation and spatial heterogeneity; (3) to develop a method for combining the drought index calculated from the inputs and outputs of WEB-DHM on the basis of sturdy algorithms for the physics of water and energy movement in the basin using monthly and seasonal differences of various drought types; and (4) to combine hydrological parameters with crop production to determine its effects on rice. The SA was calculated for the variables related to each drought type: rainfall (meteorological), streamflow and groundwater (hydrological), and soil moisture (agricultural) during 1983, 1987, 1990 -1992, and 1998 droughts. El Niño is one of the major driving forces leading to drought in the country. The drought intensified on the second year of the average two-year El Niño Southern-Oscillation (ENSO) composites with a 1 to 7 month time lag between parameters and hot spots in the upland and central plains of the basin. Recommended adaptation strategies include crop scheduling, crop/livelihood substitutes, and alternative water sources.Citation: Jaranilla-Sanchez, P. A., L. Wang, and T. Koike (2011), Modeling the hydrologic responses of the Pampanga River basin, Philippines: A quantitative approach for identifying droughts, Water Resour. Res., 47, W03514,

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This paper introduces the process of development and practical use implementation of an advanced river management system for supporting integrated water resources management practices in Asian river basins under the framework of GEOSS Asia water cycle initiative (AWCI). The system is based on integration of data from earth observation satellites and in-situ networks with other types of data, including numerical weather prediction model outputs, climate model outputs, geographical information, and socio-economic data. The system builds on the water and energy budget distributed hydrological model (WEB-DHM) that was adapted for specific conditions of studied basins, in particular snow and glacier phenomena and equipped with other functions such as dam operation optimization scheme and a set of tools for climate change impact assessment to be able to generate relevant information for policy and decision makers. In situ data were archived for 18 selected basins at the Data Integration and Analysis System (DIAS) of Japan and demonstration projects were carried out showing potential of the new system. It included climate change impact assessment on hydrological regimes, which is presently a critical step for sound management decisions. Results of such three case studies in Pakistan, Philippines, and Vietnam are provided here. integrated water resources management tools, climate change impact assessment, Asian river basins, Asian Water Cycle Initiative Citation: Koike T, Koudelova P, Jaranilla-Sanchez P A, et al. 2015. River management system development in Asia based on Data Integration and Analysis System (DIAS) under GEOSS. Science China: Earth Sciences, 58: 76 -95,The global Earth observation system of systems (GEOSS) Asian water cycle initiative (AWCI) was established in 2007 as a response to the recognized needs for accurate, timely, and long-term water cycle information to implement integrated water resources management (IWRM) practices and with regards to the commonality in the water-related issues and socio-economic needs in the Asia-Pacific region. Implementing IWRM at the river basin level, while respecting the physical, social and political context, is an essential element to managing water resources in a more sustainable way, leading to long-term social, economic and environmental benefits (GWP, 2009). It requires a wide range of disparate data from multiple disciplines and various sources and appropriate tools for processing these data and integrating and translating them into relevant information for water resources practitioners and policy decision makers. A system for supporting IWRM practices thus must be able to simulate and predict a wide range of flows from droughts to floods and to be applicable for long-term, cli-

The development of new water sources to ensure more stable water supply for Metropolitan Manila is urgently needed especially with the changing climate. The objectives of this study are: 1) to develop hydrological models in 3 river basins (Angat, Kaliwa and Pampanga) surrounding Metro Manila; 2) to assess basin-scale hydrological impacts of climate change in terms of a) flooding trends and b) drought trends. Calibrations of the basins were performed in Angat dam inflows for Angat basin; and Pantabangan dam, Cabanatuan, Zaragoza, San Isidro and Arayat stream flows for Pampanga river basin. Soil moisture verification of Pampanga river basin utilized monthly surface soil moistures from both the LDAS-UT and hydrological model outputs in short vegetation areas. Incorporating bias corrected rainfall and other parameters from GCMs showed future flooding trends is virtually certain to increase while drought trends are as likely as not to increase in the uplands but very likely to increase in the flood plains.