Tag: National Hydrography Dataset

What’s in a name? The USGS on NHD Feature Names Inspection

by Cynthia Deischer and Ray Postolovski

Juliet: “What’s in a name? That which we call a rose by any other name would smell as sweet.”

Romeo and Juliet meet in Shakespeare’s tale.  They are predestined from the start because of their surnames. Juliet tells Romeo that a name is an artificial and meaningless convention.  Meaning what matters is what something is, not what it is called.  However in the geospatial community, a name is far from meaningless and what something is named is just as important as what something is.  Continue reading

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National Hydrography Dataset Plus Version 2


by Tommy Dewald, USEPA Office of Water The National Hydrography Dataset Plus (NHDPlus) is a suite of geospatial products that build upon and extend the capabilities of the NHD (1:100,000 scale) by integrating it with the National Elevation Dataset (30M) … Continue reading

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Linking Fish Sampling Sites to the NHD

by Ariel T. Doumbouya, NHD Team, United States Geological Survey

Fish Sampling Sites in Nashuma Subbasin, MassachusettesFish sampling sites in the Nashua River Subbasin in Massachusetts are linked to the National Hydrography Dataset (NHD) as events using the Hydrography Event Management (HEM) Tools.  Events allow scientific information to be linked to the NHD which provides a powerful modeling framework that can be used to locate water related information on the network, establish up and/or downstream relationships, perform habitat and species modeling, and determine relationships between  other environmental factors.

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National Hydrography Dataset New Applications Page


by Kathy Isham, National Hydrography Dataset, USGS The US Geological Survey (USGS) has redesigned its applications page for the National Hydrography Dataset (NHD). The new applications page is organized into the six different types of applications that highlight how USGS … Continue reading

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Esri Hydro Viewer

The Esri Hydro Viewer is a Javascript application built for the Esri Hydro Basemap that allows users to interact with the map, turning a static map into an interactive information center. The application has a user-friendly interface, and allows for easy navigation and visualization of hydrologic information. The Esri Hydro Viewer adds value to the Hydro Basemap by making the data contained within the map useful and easy to understand.  Both the Esri Hydro Viewer and the Esri Hydro Basemap were built using NHDPlus products.

What it does:  The Esri Hydro Viewer presents information about watersheds, including spatial information about contributing watershed area. For example, if you click on a watershed in Texas, the application presents a detailed report of information about the selected watershed, and highlights the larger hydrologic unit that it is contained within. The report tells you what category of watershed you have selected, and gives the names of the larger contributing units, as well as the HUC number, area, mean annual flow, cumulative drainage, and a brief description of the watershed. The application presents information about the watershed and helps you visualize how your selected watershed fits into the larger national context.

Esri Hydro Viewer with Subbasin Austin-Oyester in Texas selected.

Esri Hydro Viewer with Subbasin Austin-Oyster in Texas selected.

The application also has navigational functionality that makes it easy for you to zoom between region, subregion, and subbasin scale levels, illustrating to map readers the multi-scaled nature of the data, and making those relationships easy to understand—especially to someone who is does not know much about hydrology.

Zoomed to Subregion level, Galveston Bay – San Jacinto.

Zoomed to Subregion level, Galveston Bay – San Jacinto.

How it was built: The Esri Hydro Viewer is a relatively simple application and can be customized for other data or purposes with a basic understanding of Javascript and HTML. The application, along with the required files, are available for download HERE. The application was constructed using the ArcGIS Javascript API, along with the Dojo and ExtJS toolkits to help build the interface. We also used Google Charts for drawing the charts in the reports. The included HTML file has been annotated with comments so that it is easier to edit.

The application consists of four map services – the reference layer and terrain layer that make up the base map, along with the overview map and query layer. We also implemented two widgets into the application – the Overview Map, and the Legend widgets. You can find more documentation and instructions for both widgets in the ArcGIS Javascript API Resource Center. The Overview Map widget defaults to showing the first map layer added in the application. For this application, however, we used a map that was specifically designed to be used as an overview map instead. To do this, you need to set your custom Overview Map layer visibility to false, and make sure that it is the first layer added to your map. That way, it is not loaded as the basemap, but loads only in the Overview Map widget.

Custom Overview Map layer visibility to false.

First layer added to your map.

Even though the base map you see is our Hydro Basemap, we use Bing Maps for our search functionality. To do this, you need to hide the Bing Maps layer so the geocoding works, but the layer does not appear. Using Bing Maps requires a Bing Maps application “key,” which is packaged together with ArcGIS Server 10.0. You can obtain this by going into Server Manager – Settings – and Bing Maps Key. Further instructions on using Bing Maps can be found here.

Whenever you click on the map, two queries are executed (unless you are at the Regional scale level) – one for the selected unit, and one for the larger unit that it is contained within. It looks like the second query is done using a spatial relationship, but we actually used a “query.where” to query for the unit with the same name as the selected unit. By querying based on attributes, our queries run much faster.

To select the larger unit.


The charts in the reports were generated using Google Charts, which makes it very easy to create nice looking visual aids. As you can see in the figure below, not much code is required to build the charts. We used pie charts to represent our data, but there are many other different types of charts available for use as well.

Google Charts

Google Charts

Three different report templates are specified in the code – one for the Region level, one for the Subregion level and one for the Subbasin level. The formatting is mostly done using plain HTML so it would be easier to modify the reports.

The Esri Hydro Viewer is in the Hydro Resource Center Map & App Gallery, and on ArcGIS Online.

The Esri Hydro Viewer can be customized for other data or purposes. For questions or assistance with this please contact Mapping Center.

Special thanks to Kenny Ling for providing this post. Questions for Kenny: Kling@esri.com.

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Versatile New Maps: The Medium Scale Hydro Basemap and Hydro Reference Overlay

In the bad old days, you may have done some work for a client and got to a point where you just want to make a map for a meeting or a report.  One of the most time consuming parts of making a map from scratch was finding data for rivers, streams, and lakes, then turning each an appropriate blue, making each line the appropriate symbol, then symbolizing each stream segment.  It takes time to find a dataset that is good enough, at the right scale, and that looks good when you are done symbolizing everything.  It may take you hours to find the right data, symbolize, and label everything.

In my past life as a consultant, sometimes I had to start from scratch like this. I spent time finding and downloading appropriate scale data, checking it to see if it looks OK on my map, then symbolizing each stream and lake at least a little bit (most places I have worked don’t need glaciers symbolized) so they show up with the right symbol.  Once that is all set, I haven’t even started labeling each stream, which can take quite a while to get right.

Sometimes to save my clients money I would give up and use USGS DRGs, turning only the blue symbols on.  I often thought wouldn’t it be wonderful if there was some kind of national hydrologic map service on the internet that you can just add to your map and it just works?

Now there is… in the form of the esri Mapping Center Hydro Team Hydro Basemap.  We have made a medium scale hydro basemap of the United States, from 1:147,000 to 1:18,000.  And we think it will make a lot of things easier for our community.

The Hydro Basemap of the United States is based on NHD, but with a focus on analytical cartography.  These maps are made to show hydrologic networks connecting through a system.  What’s known as the ‘Hydro Basemap’ is just the Hydro Reference Overlay plus relief… At times you may have your own relief or basemap and may not need any background behind the rivers and lakes.  For that you don’t want the whole Hydro Basemap, just what’s called the Hydro Reference Overlay. That’s the only difference in the two concepts… the presence of relief.  These two products are close companions to one another.

Hydro Basemap

Gardiner, Maine area, esri Mapping Center Team Hydro Basemap of the United States

Actually the Mapping Center Team has gone way beyond the concept I described earlier.  What we actually built is a hydro basemap, but one that is ready for a multiscale experience.  You can take one of the applications we built such as the High Water Map, then recycle/repurpose the javascript application for your needs, and the basemap is ready for you to use.  Just add your data.

 Hydro Basemap mashup with USGS Gauges

A map created on arcgis.com using the hydro basemap, mashed up with the USGS river gauge service.

As you zoom in and out, streams turn on and off, and labels rearrange for you.  As you zoom in, more and more stream segments appear that are important to your map view.  As you zoom out, smaller streams that would clutter your map view are selected out of the cache and removed.  Streams do not turn off and on indiscriminately or based solely on size or flow, there is a sophisticated algorithm at work here that will prioritize small streams with big important names (such as the upper Mississippi River in Minnesota).  In addition, different parts of the country have different methods of stream prioritization, and these are respected.  There is no one size fits all method to pruning streams as scales change, since different parts of the country have different soils and drainage characteristics. Don’t worry, we have done this for you so you don’t have to.

It’s easy to get used to something like this because (as we like to think at the Mapping Center) it’s how things should have been all along. We at the Mapping Center Hydro Team are proud of this product and would like you to give it a spin, and see how you like it.  We’d like to hear your comment to know how easy this is for you to use.  I wish they had this when I was a consultant.

Special thanks to Michael Dangermond for providing this post. Questions for Michael:  mdangermond@esri.com

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Hydrography Event Management Tool for ArcGIS 10

National Hydrography Dataset






The Hydrography Event Management (HEM) Tool Version 2.4 for ArcGIS 10 is now available!

The HEM Tool provides full functionality for adding and editing events in the National Hydrography Dataset (NHD).

Events are informational data linked to the NHD using a linear
referencing system on NHDFlowlines.  The use of events allows vast
amounts of scientific information to be linked to the NHD.

The HEM tool handles all linear referencing mechanics to make working with events easy.  It works on point, line, and area events and allows events to be located interactively, imported, or calculated.

A number of state and federal partners have adopted HEM: Environmental Protection Agency (EPA) incorporated HEM to meet Clean Water Act reporting requirements, the U.S. Forest Service incorporated HEM functionality into their National Resource Information System (NRIS) Aquatic Surveys application, Bureau of Land Management (BLM) incorporated HEM to support event creation for its Oregon/Washington Aquatic Resource Information Management System
and is evaluating its use for a national Riparian Database, and the HEM
Tool is used to georeference water quality data to the NHD, and this
information is then used for Section 303(d) water quality reports on impaired waters.

HEM effort is a unique collaboration between the BLM, U.S. Geological
Survey (USGS), and the EPA that results in ongoing tool development and
support to the expanding HEM user community.

The USGS provides basic to advanced HEM training with easy to follow exercises:

and additional user support in the Troubleshooting Guide.

OR you can request training and support on a specific HEM topic.

To find out more information visit USGS’s HEM site.

NHD Tools



Special thanks to Ariel Bates for providing the post. Questions for Ariel: atbates@usgs.gov

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