Last month the mayor of Paris went for a swim in the Seine River. It was big news because the river had primarily been used as a sewer for household sewage, industrial waste, and agricultural runoff, precluding swimming because of the danger to human health.
Spurred by the 2024 Olympics, however, the French authorities strived to make the river safe for Olympic swimming events, and they largely succeeded. Post Olympic public swimming in the Seine River is once again conceivable if the French government’s efforts continue.
This water quality mitigation performance by the French government is impressive but hardly merits a gold medal. Neither does the performance of the U.S. government as judged against its own Clean Water Act of 1972 goal to make all U.S. waters “fishable and swimmable” by 1983.
Two years ago, at the 50th anniversary of the act and 40 years after the target date for “fishable and swimmable,” an assessment indicated only about 50% of river miles and 55% of lakes (measured by area) had met the target.
The Mississippi River provides an example that illustrates why improving water quality is so difficult: Fixing one problem often exacerbates another. In his 2024 book, “The Great River,” Boyce Upholt describes how beginning in the 19th century, Congress provided authority and appropriations to the U.S. Army Corps of Engineers (USACE) to improve navigation on the Mississippi. USACE proceeded to straighten, deepen, and clear downed trees from channels.
Improving navigation unfortunately increased downstream flooding. Flooding prompted the construction of dams and levees, which led to the conversion of vast areas of the former floodplain to agriculture, industry, and towns.
During high-water times, however, when levees were in danger of being overwhelmed, USACE repeatedly had to provide emergency outlets for the Mississippi and some of its tributaries, necessitating the building of gargantuan spillways. And as extreme floods have increased in recent years so, too, have emergency releases of river water, leading to billions of dollars of damage.
Redirecting the increasingly mud laden river into the Gulf of Mexico instead of dispersing the mud onto its floodplain and coastal wetlands, as the pre-engineered river did, has led to a dead zone at the mouth of the Mississippi, which NOAA announced earlier this month is about the size of New Jersey this year, with annual damages to fisheries and marine habitats estimated by the Union of Concerned Scientists at $2.5 billion in 2020.
In recent years, Congress has also tasked USACE with rebuilding coastal wetlands, but that requires allowing water to flood the landscape. As Upholt describes, USACE’s work over the last two centuries seems too often to be fixing the problem created by fixing the previous priority problem.
All the while the quality of the water remains largely unaddressed.
Although the Clean Water Act has allowed the EPA to rein in sewage outfalls and industrial effluents, a large remaining root cause of poor water quality – runoff of soils and excess fertilizer from agriculture and livestock production – is outside the Clean Water Act’s mandate. In fact, it is largely unregulated by any U.S. agency. Water quality improves dramatically as water passes through a natural wetland, where sediments settle and nutrients are absorbed by plants. The opposite can happen when water is shunted downstream at high velocity.
In an effort to better anticipate and quantify such tradeoffs for proposed projects, USACE, EPA, and other U.S. agencies have been required in recent decades to base project decisions on a rigorous evaluation of potential benefits as well as costs. This requires quantifying the value of different ecosystem goods and services, including the value of water quality.
Economists have provided increasingly accurate ways to do so, as illustrated in last year’s special issue of the Proceedings of the National Academy of Sciences on innovations in measuring the social benefits of water quality improvements. This was a product of Cornell Atkinson’s working group on the social cost of water pollution led by Cathy Kling, in collaboration with EPA. This effort is consistent with a new larger effort by the U.S. government to regularly assess the nation’s natural capital, including its freshwater. The first year’s results of this effort were released this spring. Such metrics are not adequately represented in traditional metrics of economic health, such as GDP or capital reserves of banks.
For the French, good water quality this summer in the Parisian stretch of the Siene was clearly worth a lot. Over the last decade, the French authorities spent the equivalent of $1.5 billion on water infrastructure improvements, including sewer system upgrades, sewage treatment, and stormwater storage. To continue to improve water quality in the Seine River, the Mississippi River and many other global waters, additional policy and technology innovations and public and private investments are needed.
In the U.S. especially, innovations and investments should aim to update and apply improved water quality technology to effluents from sewage plants and industry, and to improve the quality of agricultural runoff while minimizing losses of food production. The Water Resources Development Act of 2024 now being finalized in Congress has the potential to address some of these issues.