From the rugged mountains of the Eastern Continental Divide, through the gentle farmlands of central Pennsylvania and the Shenandoah Valley, and into the heart of Nation’s Capital, Potomac Country is a patchwork of personalities. Similarly in the world of cartography, mapmakers have used their skills and imagination to depict the geography of the Potomac watershed in many different forms. Here are some of them:

The Interstate Commission on the Potomac River Basin gives us a good generalized look at Potomac Country. The first thing that becomes apparent is that the watershed is shared among four states plus the District of Colombia. In other words, the institutions responsible for governing the affairs of the watershed’s natural environment do not fit the ecological boundaries of the resource, which complicates efforts to reduce pollution and improve land management. Ideally, institutional jurisdiction should align with ecological boundaries, although for historical and political reasons, this almost never happens. One approach for improving capacity for collective action is to create a multi-jurisdictional  entity such as the ICPRR, and hope for the best.

Geographer and map wizard Robert Szucs created this masterpiece with GIS software. Despite its geographic and artistic splendor, it reminds us of how tiny the Potomac Basin is in relation to the watersheds of the United States. And how much the Mississippi basin dominates the continent. Go Natchez!

The US Geological Survey (USGS) has created what it bills as the largest-ever assessment of water-quality changes in the country’s streams and rivers, including in the Potomac watershed. Included are trends in water chemistry (nutrients, pesticides, sediment, carbon, and salinity) and aquatic ecology (fish, invertebrates, and algae) for four time periods: 1972-2012, 1982-2012, 1992-2012, and 2002-2012. The USGS map shows six water quality data points for the Potomac watershed, unfortunately all trending down.