The Chesapeake Bay Program’s latest look at watershed health reflects the reality of an impaired Bay, where population growth and pollution could threaten stable blue crab, striped bass and shad populations.
Released today, Bay Barometer: Health and Restoration in the Chesapeake Bay Watershed collects and summarizes the Bay Program’s most recent data on water quality, pollution loads and other “indicators” of Bay health, from ecological markers like underwater grass abundance to measures of progress toward restoration goals.
According to the report, more than half of the watershed’s freshwater streams are in poor condition, almost three-quarters of the Bay’s tidal waters are impaired by chemical contaminants and just 29 percent of the Bay has attained water-quality standards.
But an absence of rapid improvement in Bay health is not an indication that our restoration efforts are ineffective. Instead, it is an indication that lag-times are at play. Knowing that we will have to wait before we see visible improvements in water quality gives officials hope that the work done in 2012—like the 285 miles of forest buffers planted along waterways, the 2,231 acres of wetlands established on agricultural lands or the 34 miles of streams reopened to fish passage—will lead to results in the watershed. In fact, long-term trends indicate nutrient levels in Bay tributaries are improving, with most showing lower levels of nitrogen and phosphorous.
“Bay Program partners have made significant strides in moving us ever closer to a healthy, restored Bay watershed,” said Bay Program Director Nick DiPasquale in a media release. “We will have to exercise persistence and patience as the actions we take to rebuild balance and resilience… into this complex ecosystem… show up in the data from our monitoring networks.”
Slow-moving groundwater on the Delmarva Peninsula could push excess nutrients into the Chesapeake Bay even after we have lowered the amount of nitrogen and phosphorous we put onto the land.
Image courtesy yorgak/Flickr
According to new research from the U.S. Geological Survey (USGS), most of Delmarva is affected by the slow movement of nutrients from the land into the water. A USGS model developed to track the movement of nitrogen through the region showed that groundwater—and the pollutants it can contain—takes an average of 20 to 40 years to flow through the peninsula’s porous aquifers into rivers and streams. In some parts of Delmarva, the groundwater that is now flowing into local waterways contains nitrogen linked to fertilizer used three decades ago.
The slow flow of nitrogen-laden groundwater into the Bay could affect efforts to restore the watershed, lengthening the “lag-time” between the adoption of a conservation practice and the effect of that practice on a particular waterway. In other words, it could take days or even decades for today's management actions to produce positive water quality results.
“This new understanding of how groundwater affects water-quality restoration in the Chesapeake Bay will help sharpen our focus as many agencies, organizations and individuals work together to improve conditions for fish and wildlife,” said Lori Caramanian, Department of the Interior Deputy Assistant Secretary for Water and Science, in a media release.
While these findings seem to contradict the value of our restoration work, the study in fact indicates that pollution-reducing practices put in place over the past decade have begun to work. The study also confirms that rigorous steps taken to reduce nutrients on the land will lower the amount of nitrogen loading into streams in the future.
How poor are they that have not patience! What wound did ever heal but by degrees?
William Shakespeare, Othello, Act II, Scene 3
Between fast food restaurants and speed-of-light cell phones, we live in a culture of instant gratification. But the environment around us doesn’t operate that way. Instead, it is slow to respond to changes—like the upsets or imbalances created by human activity.
Scientific evidence shows that many of the pollution-reducing practices we are placing on the ground now may take years to show visible improvements in water quality. One reason? Pollutants can be persistent. French and Canadian researchers, for instance, tracked the movement of fertilizer through a plot of land over the course of three decades. While more than half of the fertilizer applied to the land in 1982 was absorbed by agricultural crops like wheat and sugar beet, 12 to 15 percent remained in the soil. The researchers predicted it would take an additional 50 years before the fertilizer fully disappeared from the environment.
Much of the farmland in the Chesapeake Bay watershed sits over groundwater, now contaminated with high levels of nitrates following years of fertilizer applications above ground. Work by the U.S. Geological Survey (USGS) has shown that it will take a decade for this nitrogen-laden groundwater to flow into rivers, streams and the Bay. On the Delmarva Peninsula, where deeper, sandy aquifers underlie the Coastal Plain, this so-called “lag-time” could take 20 to 40 years.
So what implications could lag-times have for the Bay restoration effort? Last year, the Chesapeake Bay Program’s Scientific and Technical Advisory Committee (STAC) released a report about the lag-time phenomenon. The team of experts concluded that lag-times will affect public perception of our progress toward meeting the pollution diet set forth by the Chesapeake Bay Total Maximum Daily Load (TMDL).
The TMDL requires the six Bay states and the District of Columbia to implement their proposed pollution-reduction measures by 2025. There may be an expectation on the part of the general public and our elected officials that once these measures are fully implemented, the Bay will have met its water quality goals. But now we know that it may take some time before we can make that claim. As 2025 approaches, we must remind the public that lag-times exist and ask for their patience in seeing a healthy Bay. Because through patience—and vigilance—the Bay will be restored.
Note: The opinions expressed above are those of the author and do not necessarily reflect U.S. EPA policy, endorsement, or action.
Cover crops, sediment ponds and streamside trees and shrubs: each of these conservation practices will slow the flow of pollutants into the Chesapeake Bay. But each will take different amounts of time to produce water quality results, according to a panel of experts convened by the Chesapeake Bay Program.
Image courtesy Uncle Kick-Kick/Flickr
In a report released this month, the Bay Program’s Scientific and Technical Advisory Committee (STAC) notes that the impacts of changes in land use and pollution loads into rivers and streams will not always be immediately reflected in changes to water quality. In fact, these so-called “lag-times”—or the stretch of time between the adoption of a conservation practice and the effect of that practice on a particular waterway—could call for patience in awaiting visible results from our restoration work.
Lag times are a natural part of our environment: as rainwater soaks into the ground, it can move nitrogen through the soil, and strong storms can pick up sediment and deposit it elsewhere. Because conditions in the Bay are a result of current human activities and a legacy of activities from the past, it makes sense that management actions taken now could take days or even decades to produce positive results. In fact, scientists know that some practices—in particular, those that take place close to rivers and streams—can produce results faster than others.
But according to STAC, this doesn’t mean that we should scale back on watershed restoration. Instead, an understanding of lag-times improves our understanding of how the ecosystem works, and reminds us to be “patiently realistic about the time-scale for observing results.”
Learn more about lag-times and the Chesapeake Bay.