The Hydro Reference Overlay - Medium Scales map template helps you create a hydro-centric reference map for 144K, 72K, and 36K scales based on a dataset that contains mean annual flow values (such as the NHDPlus).
The Hydro Reference Overlay is a reference map - just like the World Topographic Map - but with a hydro focus. It is an ArcGIS Server multi-scale cached web map service, and was built using the NHDPlus dataset published by the USGS, which includes the value added attribute Mean Annual Flow. The reference map was designed to be used as a basemap of the nation's surface water,
The streams on the map are symbolized using tapered symbology and the Mean Annual Flow values in the attribute table, which provides a unique view, and new understanding of flow in streams across the country. Using this tapered streams visualization allows map readers to easily compare the amount of water in streams from coast to coast.
The Hydro Reference Overlay is an out of the box base layer that engineers and watershed managers can use in site maps on their desktop, or in web maps on ArcGIS Online, or their own custom web mapping applications.
The Hydro Reference Overlay - Medium Scales map template provides the tools that you will need to create the 144K, 72K, and 36K scale levels of the Hydro Reference Overlay map. You just simply follow the instructions in the template package, and essentially pour your data into the template to create your own hydro-centric reference map.
We encourage you to use this template as a starting point to design your own hydro reference map.
To download the map template click here!