Water resource development projects of varied size and scales are inevitable with the ever increasing demands of the society. However, projects inherited—ranging from command areas of millions of hectares to very small local level ones have overlapping and at times conflicting objectives. Thus, there is seldom adequate coordination essential for ensuring collective sustainability. Integrated watershed development and management is the accepted answer but it in turn requires a comprehensive framework that can enable a planning process involving all the stakeholders at different levels and scales. Such a compulsory unified hydrological framework is essential to evaluate the cause and effect of all the proposed actions within the drainage basins.
Integrated water resources framework for India: A comprehensive planning process should cooperatively work towards identifying the water resource concerns, as well as develop and implement plans with solutions that are environmentally, socially and economically sustainable at various connectivity levels of the drainage system. It is important to understand that integrated water resource management should not merely imply the maintenance of an inventory of activities to be undertaken within a hydrological unit. It also requires the collation of information needed to evaluate the cause and effect of all the proposed actions within the drainage basin.
The watershed is the smallest unit where the evaluation of man induced impacts upon natural resources becomes possible. The impact at the watershed level will be experienced at a higher level within the drainage basin, and its assessment will require a regularly maintained and updated framework. The development of a hydrologic information system component is the logical response to meet the specific needs of the various end-users, which consists of a database coupled with tools for acquiring data to fill the database and tools for analysing, visualising and modelling the data contained within it.
A geographic information system (GIS) portal has been formulated using the ArcHydro data model for the general users to access the hydrological information based on the soil and water assessment tool (SWAT) hydrological modelling (Fig.2). The Arc Hydro data model (Fig.1) enables a watershed to be described in a single geodatabase which can be used by GIS based hydrologic and hydraulic model to simulate watersheds. ArcHydro provides means for linking simulation models through a common data storage system. Thus, a scheme that reflects temporal and geospatial hydrologic data was created to support surface water hydrology and hydrography modelling at any scale.
Data storage, sharing and protection: The GIS data is stored in a geodatabase using ArcSDE and Microsoft SQL server. ArcSDE allows administering spatial data stored in a relational database management system and provides access to data required for client applications. By transferring almost all GIS data into the ArcSDE geodatabase, a centralised resource for geospatial data is created that can be accessed through the intranet and internet by various GIS applications and functionalities designed to serve its many GIS users.
Distributing data and GIS functionality: With the help of built-in functionalities and customised ArcGIS Server applications that use .NET technology and Active Server Pages(ASP), allows enterprise GIS applications to be built that can be centrally managed and accessed via web-based interfaces, custom applications, or traditional desktop GIS. Built on ArcObjects, ArcGIS server can provide all the strength of advanced GIS functionalities in a distributed multiuser setting. A user can generate custom maps and tables in real time. The data delivery mechanism is streamlined, user friendly, and cost-effective.
Elements of the framework: The common framework for water resources planning and management requires creation of base layers at different scales so as to cater to the relevant problems at respective scales. However, it is imperative that all these scales should merge through the GIS environment for aggregation and integration to be possible. The major elements of the framework is shown in the Fig 1. ArcHydro data model could only meet the basic information on drainage—the geodatabase was extended to capture the information related to administrative area, landuse, soil feature class and non-spatial data. ArcHydro data model was also extended to support SWAT model output.
GIS interface for analysis of model results: The web based interface is available at www.gisserver.civil.iitd.ac.in/nat.com. Fig.2 shows the user view of the main page. The user can zoom in further to view the basin, catchment and sub-catchment level. The standardisation of the drainage area was done by giving the unique identification number at different levels, which can be used as reference for users across departments. The user has been given the option of selecting the basin, catchment or sub-catchment as per his/her interest/requirement. The user is then provided with a large range of outputs generated through the hydrological model SWAT with the different data sets such as those of India Meteorological Department for the period of 1971 to 2005, regional climate model (RCM) data sets pertaining to various scenarios, etc. The impact of climate change on water resources of the country has also been quantified using several Intergovernmental Panel on Climate Change (IPCC) scenarios.
SWAT model outputs of water balance components, flow, water quality parameters such as nitrite, nitrate, ammonium, organic nitrogen, organic phosphorus, mineral phosphorus, carbonaceous biochemical oxygen demand and dissolved oxygen, are options that are available to the user for analysis. The development of the geospatial web portal was thus to showcase the viability of the solution of addressing the complex water resources issues of the country and is a scientific platform for creating methodologies to evaluate the sustainability of the actions taken by the society as a whole.