1. HydroGET A web service client for ArcGIS Ernest To PhD Candidate, University of Texas at Austin August 2008

2. What is HydroGET? A web service client for ESRI‘s ArcGIS environment. Harvests time series data from web services and stores them in the Arc Hydro data model. Default Mode: Downloads data from national data sources to describe components of the hydrological cycle. Atmospheric data from Daymet or Unidata Surface data from USGS NWIS Subsurface data from USGS NWIS Illustration courtesy of the United States Geological Survey Custom Mode: Downloads data from any combination of CUAHSI web services to describe other properties (e.g. biological) of a study area.

3. GIS layer that contains points of interest. List of variables (each tab holds a different set of variables) Period of interest Geodatabase to store downloaded data Main Interface Types of data and sources User inputs Data from user- specified sources for single point Subsurface data from USGS NWIS Surface data from USGS NWIS Data from user- specified sources for multipoints Atmospheric data from Daymet and Unidata Default Mode Custom Mode HydroGET Interface

4. Default Mode The default mode of Weather Downloader describes the hydrological history of a given location by downloading time series from public data repositories. For this demonstration, we have selected the San Marcos basin in central Texas. The basin is located between the cities of Austin, TX and San Antonio TX. It isis situated over the Edwards Aquifar, a major source of fresh water for the region. Legend Watershed centroids (Daymet) USGS groundwater gages (USGS NWIS) USGS streamflow gages (USGS NWIS) San Marcos basin in central Texas HydroGET in action (Demo I)

5. Assembling data for hydrological insights Precipitation data from watershed centroids Streamflow data from USGS gages. Groundwater data from USGS wells. Precipitation (cm) Streamflow (cfs) Groundwater level (m above ground surface)

6. What HydroGET needs to call a web service Query ParameterExplanationExample WSDL Web Service Description Language (WSDL)http://water.sdsc.edu/wateroneflow/NWIS/Daily Values.asmx?WSDL NETWORK Name for the sensor networkNWIS SITECODE Site code of the monitoring point08170500 VARCODE Variable code for the variable of interest00060 STARTDATE Start date for the period of interest1/1/2000 ENDDATE End date for the period of interest12/31/2003 AUTHCODE Authentication code for security reason Query ParameterExplanationExample HydroID ID assigned to the site (Long Integer)1000004 TSTypeID/ VarID ID assigned to the variable (Long Integer) 1003 Underneath the hood What HydroGET needs to store data in Arc Hydro

7. Making Arc Hydro data user-friendly with SQL queries Join Pivot 2. Join (Use a query to join the TimeSeries table with TSType table and the featureclass attribute table) 3. Pivot (Pivot the joined table by Variable field to create a MultiColumn table) MultiColumn table Joined table 1. Arc Hydro data model (In Arc Hydro, time series information are stored in three separate tables: TSType, TimeSeries and a featureclass containing the monitoring sites) Join Time series format is optimal for storing data but not necessarily for data analysis.

8. Multicolumn table All the time series data from the Arc Hydro geodatabase can be integrated into a single understandable, multicolumn table using queries. Each record in the table contains all variables measured at the same point in space and time. Latitude, Longitude, Offset and Time information are also provided within each record. Multicolumn format is more amenable to data analysis. Because the table is actually a query, when underlying time series data are updated with HydroGET, the multicolumn table gets updated as well.

9. Conclusions HydroGET and MySelect are useful tools for harvesting from CUAHSI web services. Semantic differences between different data sources can be mediated by MySelect. SQL queries allow instantaneous conversion of Arc Hydro time series into a format suitable for analysis. HydroGET is available at http://his.cuahsi.org/hydroget.html http://his.cuahsi.org/hydroget.html