Role of Arc GIS in developing Real Time and Forecasting Water Resource System ANMOL BHARDWAJ 1, ANIL VYAS 2 1 Project Associate, Indian Institute of Technology Roorkee 2 ADE National Hydrology Project, Bhakra Beas Management Board Chandigarh NHP, Bhakra Beas Management Board, Industrial Area Phase I, Chandigarh Word Limit of the Paper should not be more than 3000 Words = 7/8 Pages) Abstract: About the Authors: Arc GIS tools were used to delineate watershed of Sutlej and Beas using Digital Elevations Model. Using Er. Anil Vyas this flow direction, catchment, sub catchment, Experience: drainage line, cross sections for a watershed were obtained. This data is then exported to hydrological softwares for making models. The conventional systems has various limitations in analyzing Achievements: catchments having transboundary conditions, inaccessible catchment area due to terrain conditions, reliance on human intervention etc. The major part of Sutlej catchment resides in the China where the telemetry stations cannot be installed. There are some sites where telemetry gages have sparse distribution, so in those areas we are completely dependent on satellite data. Forecast and Real Time satellite data are downloaded in the form of grib, grib2, netcdf, tif from ftp servers and converted into appropriate format automatically using Arc GIS Model Builder tools and scripts. The process of data acquisition and decoding is completed within a few minutes. The results of using grid to grid calculation technique instead of using conventional techniques were compared. As Indian telemetry is in developing stage so data availability from all the stations is a matter of concern. Map to map tools (inverse distance weightage) of Arc GIS were Er. Anmol Bhardwaj used to make the system dynamically flexible to use the available number of stations. Different scenarios available in ensemble forecast were explored with the help of Arc GIS model builder and scripts. The data processed is being used into the hydrological, hydrodynamic and reservoir simulation models in real time for further analysis. The time series animation of the input and output data is visualized using tracking analyst. 3D visualization of terrain is done using Arc Scene. 26 years in hydropower and Water Resource Sector and 8 years experience in GIS, Water Resources and Watershed modeling. Member of Software & Protocol finalizing committee for Modelling Studies in National Hydrology Project, India. Participated in Technology Enhancement tour of US on May 2009 for development of RTDSS(Real Time Decision Support System) to World Bank headquarters Washington and USBR Denver Colorado. Selected for training programme of Danida Fellowship Center, Copenhagen, Denmark of the Danish Ministry of Foreign Affairs. Gold medal from BBMB for development of RTDSS ) of Sutlej and Beas. E mail ID: avbbmb@gmail.com Contact: +91 9464317318 Working on renowned forecast and Real time data GFS, ECMWF, IMD, NCMWRF, TRMM/GPM (gridded as well as point data) for use in River Basin Planning and Real Time forecast and automated the processes of RTDSS (1st of it's own kind in India) for Sutlej and Beas Catchment of BBMB, Chandigarh. E mail ID: anmol.bhardwaj5@gmail.com Contact: +91 9464330551 Page 1 of 8
Introduction Sutlej and Beas catchments are lifeline of North West India and also feeding power, irrigation area etc. It is driving the Indira Gandhi Canal system which fulfills the irrigation (8750 km 2 ) and drinking water demands in the Thar desert. It is an essential component of HP-II. Arc GIS is one of the foremost solution provider in GIS which integrates the relation between spatial data and time. Arc GIS has the capability of inclusion of Arc hydro tools (HEC Geo HMS and Geo RAS toolbars). The GeoHMS toolbar gives the output for hydrologic model whereas the GeoRAS toolbar provides the output for hydrodynamic model for the development of a watershed model. Arc GIS tools are used to delineate watershed using Digital Elevations Model. Using this flow direction, catchment, sub catchment, drainage line, cross sections for a watershed were obtained. This data is then exported to hydrological softwares for making models. The conventional systems and methodologies has various limitations in analyzing catchments, especially catchments having transboundary conditions (where one cannot install a station for getting the information), inaccessible catchment area due to terrain conditions (snow, high altitude etc.), reliance on human intervention etc. There are similar problems in the Sutlej Catchment. The major part of Sutlej catchment resides in China territory where the telemetry stations cannot be installed, also there are some sites where telemetry gages have sparse distribution, so in those areas we have used the satellite data. Forecast and Real Time satellite data are downloaded in the form of grib, grib2, netcdf, tif from ftp servers and converted into appropriate format automatically using Arc GIS Model Builder tools and scripts. The data acquisition and decoding is completed within a few minutes. The results of using grid to grid calculation technique versus conventional techniques are compared. As Indian telemetry is in developing stage so data availability from all the stations is a matter of concern. The solution has been done with Map to map tools (inverse distance weightage) of ArcGIS [1]. With the help of this, the system is dynamically flexible to use the available number of stations. Different scenarios available in ensemble forecast were explored with the help of Arc GIS model builder and scripts. The data processed is used into the hydrological, hydrodynamic and reservoir simulation models in real time for further analysis. Various other application of Arc GIS were explored in data visualization. Application of Arc GIS (i) Delineation Catchment is delineated using Arc GIS and information such as Flow Direction, Catchment, Rivers etc. were fetched. 1 Digital Elevation Model 2 GeoHMS Toolbar GeoRAS Toolbar 3 Water Resource Software Page 2 of 8
(ii) Introduction to Model builder Model Builder is a very powerful Graphical User Interface which will help users to automate stuff without the knowledge of scripting languages. It is loaded with the iterators, system tool boxes, external toolboxes etc. Inclusion of Python scripts in Model Builder is very useful for it's developers. The file Handling with their name, extensions and arguments is done very easily in Model Builder. (iii) Fig:1 Arc GIS Model Builder Scripts To automate the stuff the scripts can be derived and then customized by exporting it from ArcGIS Model Builder. Alternatively, scripts could be written and used as a tool in the model builder. Adding python scripts is very easy in model builder. Fig:2 Arc GIS Python script using IDLE (Integrated Development and Learning Environment) Data Sources (i) Global Forecast System GFS is numerical prediction weather model run by NOAA. This system is run at a frequency of 6 hours. It gives upto 10 days forecast of various parameters such as Wind, Mean sea level pressure, Temperature (absolute, min and max), Isotherm, CAPE and CIN (surface), Cloud cover, Relative humidity, Total precipitation, Snowfall, Snow depth etc. The forecast is available at different resolutions of.25,.5, 1 and 2 with possible time intervals of 3,6, 12 and 24 hours. The data is available in grib files archived in tfw. [2] Page 3 of 8
(ii) (iii) (iv) European Center for Medium Weather Forecast ECMWF is a similar forecast model and is widely used in today's environment. It gives absolute products as well as forecast ensembles with 50 scenarios. The information provided is cumulative in precipitation. The data is available in the form of grib2 files. [3] Tropical rainfall Measuring Mission/Global precipitation Management TRMM gives the precipitation for the whole earth with interval of 3 hours, 1day,3 days and 7days with a resolution of 0.25X0.25. GPM is a similar system for precipitation which gives information at 0.5 hour, 3 hour, 1day, 3days and 7 days. The files are available in tiff format. [4-5] Global Land Data Assimilation System GLDAS temporal resolution is 3 hours, the ftp server provides various parameters such as evaporation, pressure, temperature, wind speed, cloud cover, soil moisture content, snow water equivalent, snow melt etc. This data can be used for fetching snow parameters for the model. The data is available in grib format. [6] For realizing the above inputs to the model, the inputs need to be converted into appropriate format. With the help of Arc GIS scripts or model builder tools the data can be converted from tif, grib, nc, grib2 etc. to any format as per requirement (in our case we need. dss and.csv files). Conventional Method vs Modern Method Conventional Method uses point data as the data sources. Grids are converted into points and then used in the model. With Arc GIS a more advanced system could be made which will be a grid to grid model. The output of the climatic models could be directly coupled to the hydrologic models. The modern method saves processing time as well as does not alter the accuracy and precision of the climatic output. Data sources for Real Time grids are TRMM and GPM whereas for forecasting RIMES (Regional Integrated Early Warning System for Asia and Africa), IMD (Indian Metrological Data forecast), GFS (Global Forecast System), ECMWF (European Center for Medium Weather forecast), ECMWF ensembles are used. The grids of precipitation and temperature are shown below in Fig 3(a) and (b). Fig:3(a) Temperature grid set for input to Model Page 4 of 8
Fig:3(b) Precipitation grid set for input to Model Indian Telemetry Indian telemetry is in developing stage, so the data contains missing values. The stations do not have much dense network. Using IDW of Map to Map of Arc GIS this issue is resolved by interpolating the point data to grids. The system was made dynamically flexible according to the station data available. This is very efficient technique as compared to the rigid thiessen polygon. This technique uses the available stations data and interpolate them into grids. Results The grid cell file obtained from Arc GIS is used in the hydrological models for analysis of gridded data input. Fig:4 Grid Cell File of Sutlej Basin Page 5 of 8
From Arc GIS various resolution grid cell file could be obtained. The available grid cell resolutions are 10, 20, 50, 100, 200, 500, 1000, 2000, 5000 and 10000. The available grid cell types available are SHG and HRAP stands for Standard Hydrologic grid and Hydrologic Rainfall Analysis Project. The snow accumulation in various bands can be calculated using the Arc GIS tools and then used in the model for snowmelt analysis. Fig:5 Snow accumulation in different Elevation bands Figure 5 contains MODIS snow imagery along with the elevations. Using Arc GIS tools the snow accumulation was calculated and given as input to the model. This helped the model calibrations during snow accumulation and melting period. The results are shown in Figure 6. Fig:6 Observed vs Simulated flow from model Page 6 of 8
The figure below contains the output of hydrologic models using gridded data. The efficiency of model is greater than 70 percent which is constantly improving. With these models and ArcGIS model builder tools and scripts we are producing 15 days forecast from input from ECMWF, 10 days forecast obtained from GFS, 3 Days forecast obtained from IMD as well as RIMES. The result of the model is shown below in Fig 7(a) and (b). Fig:7(a) Observed vs Simulated flow from model Fig:7(b) Observed vs Simulated flow from model Page 7 of 8
Conclusion Modern systems will consist of gridded data. The Arc GIS is able to handle those grid files. Using a decoder and ArcGIS tools the gridded data can be converted into appropriate format as per requirement. The problem of Sutlej catchment in China and high altitudes has been solved using global gridded data sources. The Sutlej catchment had areas where the stations were having sparse distribution. The existing system was made dynamically stable using IDW interpolation of stations into grids. The repetitive tasks are performed using model builder and scripts. Few problems in model builder can be sorted out in scripts and vice versa. The model builder and scripts saved a lot of human efforts and time. The common mistakes that occurs with human intervention are minimized. The scripts from Arc GIS could be scheduled to be run automatically and a complete autonomous system could be made. The complete autonomous model will download, process and will give results. This kind of system will require minimum human intervention. The efficiency of model increased. The different forecast helps in making decisions regarding water management and better operation of reservoir. The system made will also help in flood and drought management. Early waning can be issued with this system in case of a hazard. References 1. "IDW" Retrieved from http://pro.arcgis.com/en/pro-app/tool-reference/spatial-analyst/idw.htm/. 2. "Global Forecast System" Retrieved from https://www.ncdc.noaa.gov/data-access/model-data/modeldatasets/global-forcast-system-gfs/. 3. "ECMWF Forecasts" Retrieved from http://www.ecmwf.int/en/forecasts/. 4. "Tropical Rainfall Measuring Mission" Retrieved from https://pmm.nasa.gov/trmm/. 5. "Global Precipitation Measurement" Retrieved from https://www.nasa.gov/mission_pages/gpm/main/. 6. "Global Land Data Assimilation System (GLDAS) Data Products" Retrieved from http://disc.sci.gsfc.nasa.gov/services/grads-gds/gldas/. Page 8 of 8