Since about 1997 or so, I’ve been looking at USGS daily flow data. I also started using ESRI’s GIS software around that time as well. Despite being released last December, I just found out about this tool only a few days ago. Now that I’ve given it a spin, I am very impressed. ESRI’s latest version of ArcGIS (version 10) and the USGS NWIS Snapshot tool are perfect companions.
Here’s a link to the 2 page summary of the USGS tool: http://pubs.usgs.gov/fs/2011/3141/
This link will take you to the download and software support page: http://txpub.usgs.gov/snapshot/default.aspx
Assuming you have ArcGIS Desktop version 10, installation is pretty straight forward. The only additional data a user would likely need is a shapefile or feature class for a watershed area of interest. The documentation walks a user through the process of searching for surface water sites and obtaining the mean daily flow values. Once those data have been obtained, it’s just a matter of personal preference how a user would then want to use that data. ArcGIS has some built in graphing options, the data could be imported into Excel, or a user could use another graphing piece of software.
The Snapshot tool is one of the easiest to learn tools that I’ve seen in terms of being able to obtain mean daily flow data from USGS gages. In under ten minutes, I was able to create hydrographs of five stations that have collected flow data within the Ipswich River watershed. Personally, I think that’s pretty amazing.
CUASHI has developed HydroGET (http://his.cuahsi.org/hydroget.html) and HydroExcel (http://his.cuahsi.org/hydroexcel.html) which in many ways will ultimately do the same thing for a user as far as obtaining mean daily for values from the USGS is concerned. HydroExcel can search WebServices other than just the USGS and HydroGet will search for precipitation stations. Nevertheless, I think the NWIS Snapshot tool has the best user interface and is the easiest to execute.
The Snapshot tool along with CUASHI’s HydroDesktop (http://hydrodesktop.codeplex.com/) allow hydrologists to discover water resource data sets rather quickly using a GIS software. Generating graphs with these tools is also a fairly quick affair. Weather working on a pre-project proposal or if you are in the depths of a project, these two pieces of software should prove rather handy and time saving tools.
The Channel Restorationist 