Esri Hydro Reference Overlay

<p><span style='color:#b22222;'><span style='background-attachment:initial; background-clip:initial; background-image:initial; background-origin:initial; background-position:initial; background-repeat:initial; background-size:initial;'><strong>Retirement Notice:&nbsp;</strong></span></span><strong>This item is in </strong><a target='_blank' href='https://goto.arcgis.com/lifecycle/content' rel='nofollow ugc noopener noreferrer'><strong>mature support</strong></a><strong> as of&nbsp;June 2025 and will be retired in December 2026.&nbsp;A&nbsp;</strong><a target='_blank' href='https://www.arcgis.com/home/item.html?id=a69f14ea2e784e019f4a4b6835ffd376' rel='nofollow ugc noopener noreferrer'><strong>new version of this item</strong></a><strong>&nbsp;is available for your use.</strong> Esri recommends updating your maps and apps to use the new version.</p><div><div>This tile layer is designed to provide a a hydrologically oriented set of features to use with the&nbsp;World Terrain Base Layer&nbsp;or other simple base maps. The map features a hydro-centric design based on the amount of water flowing within the drainage network such that symbols of the same size and color represent roughly the same amount of water.&nbsp;</div><div>&nbsp;</div><div>This map shows surface water flow as a linear phenomenon even over and through bodies of water. Using the best available data we show relative flow accurately, so that if one river carries more water downstream than another river, the result will be that the river will have a thicker symbol on the map.</div><div>&nbsp;</div><div>This map is used as an overlay for content such as elevation from the&nbsp;World Terrain Base&nbsp;service or thematic services such as soil units, vegetation, or ecoregions. Combined with a basemap and your map services, this map provides a frame of reference for showing regional, national, and continental hydrologic phenomena such as drought, runoff, river level monitoring and flood forecasting.</div><div>&nbsp;</div><div>River names are collected in the UTF8 character set so river names are collected in their original language but are written in the Roman alphabet. Sources for all river names are from the open source geonames.org project so they are international by nature.</div><div>&nbsp;</div><div>The map is compiled from several sources. The global scales (very small scales through 1:2,300,000) include content from: HydroSHEDS, GTOPO30 Global Topographic Data, SRTM, GLWD, WorldClim, GRDC, and WWF Global 200 Terrestrial Eco Regions, with the latter three providing the inputs and basis for calculating flow. &nbsp;At medium scales (1:36,000 to 1:2,000,000) this service currently contains only U.S. data from the NHDPlusV2 that was jointly produced by the USGS and EPA.&nbsp;</div></div>