Two Chesapeake Bay Program tools hold the key to 40 years of watershed data

Since 1984, the Chesapeake Bay Program has monitored the health of the Chesapeake Bay and its tributaries at more than 130 stations. In order to understand changes taking place in the estuary, an analysis team within the Bay Program has created two products that interpret the data and showcase long-term and short-term trends. 

Tributary summaries

The Chesapeake Bay Program’s tributary summaries are in-depth reports depicting trends in water quality data at individual tributaries or a cluster of tributaries that drain to the Bay. The 12 reports summarize environmental factors like dissolved oxygen and water clarity, while connecting these data to recent research and what’s happening on the land. This allows readers to look beyond annual pollution measures and understand how the geology, land use and conservation practices in the region affect a river’s water quality. 

One popular tributary summary covers the Choptank River and its watershed. Located on the Eastern Shore of Maryland, the Choptank is the largest river on the Delmarva peninsula, with a watershed covering almost 2,000 square miles. The Choptank tributary summary offers insight into the changes taking place in the region, with maps and graphs showing both long-term water quality trends since 1985 and more recent trends from the past 10 years. 

The Choptank tributary summary has provided useful background information to one team in the Chesapeake Bay Program building a dynamic model for evaluating future conditions in the river. For example, tributary maps of the Choptank have shown that most of the river is not meeting dissolved oxygen standards, a crucial component for aquatic systems to support life. Similar information from the tributary summaries can be used to guide decisions on where modeling or conservation efforts can be most useful. 

Geonarratives

Similar to tributary summaries, geonarratives also provide information on trends within Chesapeake Bay tributaries. Geonarratives adapt the same data used in each tributary summary, but take the form of a compact and interactive website, highlighting visual data and community organizations local to the region. 

One example of the Bay Program’s geonarratives is on a portion of the Bay’s mainstem in Maryland, referred to as the Maryland mainstem. This cluster of tributaries includes the Susquehanna River basin and upper Chesapeake Bay shorelines, stretching north through Maryland, Pennsylvania and New York, covering about 120,000 square miles. 

As shown in the geonarrative, over the long term, all 14 monitoring stations in the Maryland mainstem show a decrease in nitrogen, a nutrient that enters tributaries from urban and agricultural runoff, wastewater and air pollution. This trend indicates major improvement in water quality, since excess nitrogen fuels harmful algal blooms in waterways and can kill marine plant and animal life. 

Local governments and communities can utilize geonarratives to showcase these environmental improvements and foster support for clean water initiatives. Similarly, the Maryland mainstem geonarrative can provide a data-driven background helpful in setting regional goals and visualizing trends across a large watershed. 

Although the Chesapeake Bay Program’s tributary summaries only use tidal data, a non-tidal network geonarrative is also available through the Non-Tidal Water Quality Monitoring Program, which tracks water quality trends in tributary creeks and branches upstream of the Bay. The non-tidal network encompasses 123 monitoring stations that record water quality factors, similar to the tidal tributary summaries and geonarratives. This geonarrative can provide insight on trends in the headwater regions of the Chesapeake Bay watershed.

Understand your river’s water quality

The Bay Program’s tributary summaries and geonarratives are all publicly available and free to download. Whether you are a concerned resident, local elected official or leader of an environmental nonprofit we encourage you to dig into your waterway’s data. 

All tributary summaries and geonarratives can be found on the Chesapeake Bay Program project webpage. New geonarratives are being created as past tributary summaries are updated, so look out for the Choptank River, Maryland mainstem, Lower Eastern Shore and York River geonarratives this fall!