South River Report Card

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Since 2007, the Federation has compiled an annual South River Scorecard. Each year, the Scorecard presents data on key indicators of River health, such as: water clarity, dissolved oxygen, underwater grasses, and the abundance of aquatic life.

Much of the data in the Scorecard has been collected by the South Riverkeeper, but the report also utilizes data from a variety of respected sources such as the Maryland Department of Natural Resources and the Virginia Institute of Marine Sciences.

Click here for the summarized 2018 South River report card.

To view our interactive data map, that contains historical graphs for dissolved oxygen and water clarity, click here. We hope to add West/Rhode data in 2019!

Rain Leads to Poor Scores

We have long known that heavy rain washes pollution from the land into our rivers. Rainfall in 2018 was the highest ever recorded for the Baltimore metro area. The U.S. Naval Academy showed a 65% increase in rainfall between 2017 and 2018, and the River suffered accordingly.

The South River’s overall score dropped from 56% to 51%, and we saw declining scores in every major parameter measured. The month of May alone received 6.22 inches of rain, the greatest amount of rainfall for this month that we have seen in our past eight years of sampling.

Excess Nutrients Lead to Algae Blooms

This year’s rain washed large nutrient loads, including nitrogen and phosphorous, into the South River. While nutrients are critical for the maintenance of a healthy aquatic ecosystem, in excess they can quickly become debilitating. Lawn fertilizers, leaking septic tanks, and compromised sewage lines are the main contributors of nutrient pollution. Perhaps, the most harmful consequence of such nutrient levels are algae blooms.

This spring, the South River water turned a dark brownish-orange color. Locals call this algae bloom  a Mahogany Tide (see photo on right from Chesapeake Bay Program). This bloom caused the pH of the water to increase and become more alkaline, or basic. The high pH alone came close to causing a massive fish kill, as pH levels throughout the water column approached the threshold for fish survivability. At first, our quality assurance data experts suspected such high pH readings would have been impossible without a corresponding fish kill and was more likely the result of malfunctioning equipment. However, after some research, it became clear that some fish are able to withstand alkalinity levels above their claimed tolerances for limited periods of time before falling irreparably ill.

An algae bloom called a "mahogany tide" in a tributary of the Chesapeake Bay.

An algae bloom occurs when large amounts of algae, or floating plant matter, grow in one area over a short period of time. As the algae grow near the water’s surface with access to abundant sunlight, they produce high amounts of oxygen, (over 150% saturation depending on season). As the short-lived algae die and sink, bacteria go to work, decomposing the algae. In doing so, they simultaneously consume enormous amounts of oxygen in bottom waters, creating an area with extremely low oxygen levels. Commonly referred to as a “dead zone,” this area becomes barren of life, as aquatic organisms that rely on this dissolved oxygen are forced to move to more suitable waters or perish.

A Clear Link Between Stormwater and Nitrogen

In 2018, Maryland Department of Natural resources observed the highest levels of both nitrogen and phosphorous in four years. Nitrogen in particular seems to be, not surprisingly, correlated with monthly rainfall during the sampling season.

Usually, nutrient concentrations of this caliper (>=0.2mg/L nitrogen, >= 1.3mg/L Phosphorous) are infrequent; seldom occurring more than once per year. However, in 2018, nitrogen and phosphorus levels both spiked above these levels twice, a phenomenon we have not seen since 2011, when Tropical Storm Lee came through the Chesapeake region.

Phosphorus Levels Spike Alarmingly High

Coincidentally, a large number of gates at the Conowingo Dam, stationed at the mouth of the Susquehanna River, opened during the same months as these peaks occurred. After the gates opened, the Bay and the South River saw huge amounts of debris, which had been building up behind the dam, make its way downstream. The South Riverkeeper pulled a great deal of debris from the South River this summer from logs to broken plastic buckets and plastic bottles. Likewise, many water front communities organized clean ups to clear their shorelines.

Conowingo Releases Debris

Coincidentally, a large number of gates at the Conowingo Dam, stationed at the mouth of the Susquehanna River, opened during the same months as these peaks occurred. After the gates opened, the Bay and the South River saw huge amounts of debris, which had been building up behind the dam, make its way downstream. The South Riverkeeper pulled a great deal of debris from the South River this summer from logs to broken plastic buckets and plastic bottles. Likewise, many water front communities organized clean ups to clear their shorelines.

However, we are unable to conclude whether or not this event had an influence on our river’s water quality. As a matter of fact, our data actually shows insignificant water quality changes in the majority of the South River. The overwhelming amount of South River’s pollution does not come from the Bay, but from the communities of the South River Watershed.

Volunteers at the Annapolis Maritime Museum clean up debris released by the opening of the Conowingo Dam in Annapolis, Md., on Aug. 1, 2018. (Photo By Kaitlyn Dolan/Chesapeake Bay Program)
Volunteers at the Annapolis Maritime Museum clean up debris released by the opening of the Conowingo Dam in Annapolis, Md., on Aug. 1, 2018. (Photo By Kaitlyn Dolan/Chesapeake Bay Program)

How Dirty is the River?

Dirt is one of the most troubling pollutants plaguing the South River, as it can prevent the growth of underwater grasses, suffocate fish spawning grounds, clog gills, and bury oyster beds.

We are often asked, “How dirty is the South River?” In the past we’ve answered that question by assessing water clarity which improves as you head toward the river’s mouth. However, this year, we took water samples and sent them to a lab to analyze the amount of total suspended solids– the closest measurement we have for tracking dirt.

The results indicate that in general, we have higher levels of total suspended solids at the headwaters, or the top, of the river. Stations at the top are more heavily influenced by land use and human activity than stations closer to the mouth, where the Bay can dilute them.  The EPA has officially listed the South River as impaired for sediment (dirt) and set a goal of 22% decrease.

This illuminates the main purpose for our restoration projects: to prevent pollution from making its way from the land of the South River watershed into the South River itself. We pursue this by terraforming streams and adding structures to slow the water, allowing pollutants to settle out and be absorbed by plants installed on site.

Now for the Good News…

Bacteria Levels Drop at Church Creek Headwaters

Overall, bacteria rates for the South River worsened from the 90% passing score in 2017 to 85% in 2018. However, Bacteria levels at the tidal headwaters of Church Creek have steadily dropped since the completion of  our restoration project in 2014! Since then, we have constructed two more stream restoration projects further upstream.

Church Creek Headwaters is one of our largest restoration projects. It involved restoring a series of braided ditches into a set of lush wetland pools. The site has begun to rebound with biological life, sporting greater diversity and richness of fish and amphibian species than before (post restoration saw fish populations 10x pre-restoration levels).

Church Creek in Annapolis, MD has been a high priority restoration goal since the Federation’s first strategic restoration plan in 2005. Over 50% of its 1,300 acre watershed contains impervious surfaces (watersheds start to see wildlife impairment at 5%). The creek struggled under the immense amount of polluted stormwater, leaking sewage and septic systems, and long history of illegal dumping. Over 20,000 native trees, shrubs, and plants were planted. Learn more: http://www.arundelrivers.org/restoration/stream-wetlands/church-creek/

Soon We’ll Be “Shell”abrating!

One unique upcoming restoration project will not only arrest shoreline erosion, but also provide stellar habitat for oysters. On Glebe Bay at Turnbull Estates, the Federation has partnered with Ecosystem Planning and Restoration (design firm), Chesapeake Bay Foundation, and Coastal Conservation Association on an innovative living shoreline that incorporates oyster reef balls into the design. The reef balls will promote oyster growth in the nearby oyster Sanctuary Reef and stabilize the rapidly eroding shoreline.

The Eastern Oyster, Crassostrea virginica, requires certain environmental conditions to thrive. However, the rain in 2018 reduced the level of salinity in the South River waters, making it a difficult year for oysters to thrive and reproduce. While oysters were not as productive, the salinity drop did allow Dark False Mussels, another natural filter, to make a return in some of the creeks. Supporters reported sightings of Dark False Mussels in Harness Creek, Church Creek, and near Donovan’s Pier.

Silver Lining

While all the rain in 2018 led to poorer water quality for the South River, the record rain and fresher (reduced salinity) waters also caused an absence of jellyfish this summer. In a rare event, the South River experienced no jellyfish, which only happens once every several years. The absence of jellyfish may make for more pleasant swimming outings, but it is not ideal for oysters. Fewer jellyfish, which feed on comb jellies, mean fewer predators to keep the comb jelly population from preying too much on oysters in their larval stage.

https://wamu.org/story/18/08/14/marylands-jellyfish-gone/#.XJvHW5jYpPY