Principal Aquifers of the 48 Conterminous United States, Hawaii, Puerto Rico, and the U.S. Virgin Islands

This map layer contains the shallowest principal aquifers of the conterminous United States, Hawaii, Puerto Rico, and the U.S. Virgin Islands, portrayed as polygons....本地图图层包含美国本土、夏威夷州、波多黎各以及美属维尔京群岛范围内的最浅主要含水层（principal aquifers），该类含水层以多边形要素形式进行可视化呈现。