Study Shows Rivers’ Quality Declined
River Keepers give a “D plus” rating to water quality of Milwaukee’s estuary.
The study is by the Milwaukee Riverkeeper, a non-profit that advocates for and keeps meticulous data on water quality in the region. The group annually studies the Milwaukee river basin, which includes the Milwaukee, Menominee and Kinnickinnic river watersheds.
Viewed long-term, the group’s experts note, water quality in the basin has improved markedly in the past century. But from a year-to-year point of view, water quality can improve or decline. Using data collected over the course of a year, Riverkeeper’s annual report gave the basin a D+ for 2016, down from a C in 2015.
Zac Driscoll, water quality specialist for the group, cautions that “it doesn’t necessarily indicate a long term trend in decreasing water quality.”
That’s because he’s accounting for a number of factors like seasonal variation, expanded monitoring efforts by their team of citizen-scientists, new parameters of water quality being measured, and new methods for grading a particular part of the river basin.
Still, a D+ is obviously not optimal. “How would your mom take a D+? Probably not good,” says Cheryl Nenn, a longtime Riverkeeper staff member. “You’d definitely hide your report card from your mom.”
Good News, Bad News
The Milwaukee estuary — the confluence of the Milwaukee, Menominee and Kinnickinnic rivers in the greater downtown area — actually scored higher in water quality than all but one subwatershed in the region.
The estuary’s quality is largely due to its proximity to Lake Michigan. The giant body of water rocks back and forth, “kind of like a bathtub,” Driscoll explains. This water, typically of a higher quality than the river water in the basin, infiltrates in and out of the estuary diluting the concentration of pollutants.
For this reason, the Kinnickinnic river watershed scored relatively good in past years because it was measured with the estuary included. But this year, when Riverkeeper’s study separated the watershed from the estuary in its measurements, the analysts found, to no surprise for them, that the KK has incredibly poor water quality, much of it irreversibly so.
A major contributing factor to the watershed’s degraded quality is that it’s one of the most urbanized watersheds in the state. About 90 percent of the land in the watershed is designated urban and about 40 percent has an impervious surface, according to the state Department of Natural Resources. There’s an incredible amount of concrete around the river, dumping trash and waste along with other pollutants into runoff flowing into the river. Driscoll has seen an oily sheen on the water at times while monitoring water quality during a rain event.
Much of the river itself has been concretized to get the stormwater out of the neighborhoods and downstream as fast as possible, Nenn says. But this can increase the total amount of pollutants in the river, according to a DNR fact sheet.
Along with the runoff from the predominantly urban, concretized surroundings, pollutants find their way in from industrial uses. Or in the case of some of the creeks in the southern part of the watershed, from the airport.
Nenn says the airport has made a lot of improvements. But the watershed still gets de-icing chemicals showing up in a few streams. In past years, Wilson Creek would glow pink or green during the winter from chemicals used at the airport, she notes.
The river basin’s water quality is highly dependent on the surrounding land use and the season.
The basin received a B+ overall for chloride in 2016. This is good, because chloride levels have an important role in biodiversity of a body of water. Organisms living in the freshwater streams of the Milwaukee basin need the salt concentrations in their body to be higher than that of the surrounding water. Too much chloride in a particular stream can mean fish and other organisms start to die or can’t live there anymore.
But while the river basin scores relatively well on average on chloride, measurements can vary greatly depending on the season. In the winter tons of salt are dumped on our roads and much of it is washed into our streams. So a parameter like chloride can have a relatively good annual grade, but that doesn’t mean it won’t spike at certain times of the year or cause a fish kill in some part of the basin.
In this state, construction slows down during the winter. But when it picks up again in the summer, it leads to inordinate discharges of sediment into the watersheds. “All the dirt and gravel and junk, a lot of that stuff is just going right into the storm drains and most of those storm drains go right to the river,” Nenn says.
Sediment, along with other debris and nutrients, can cause changes to the ecology of streams through plant and algae growth. These growths can affect the temperature and oxygen levels of streams that can impact freshwater life.
In the summer there also tends to be droughts: that means less water in the streams, which causes a higher concentration of pollutants.
Failures in our Streams
Three parameters of water quality measured by the Riverkeeper have been consistently poor. The levels of phosphorous, bacteria and specific conductivity in the river basin each received a failing grade.
In the north branch of the Milwaukee River subwatershed, the study found disconcerting measurements for specific conductivity. This parameter is basically a measurement of a stream’s ability to pass an electrical current. The geology of a stream will naturally have a bearing on its specific conductivity, but this measurement can be impacted by the presence of charged particles, which can enter the stream through phosphates, chloride and heavy metals.
The north branch had the worst grade for specific conductivity of the entire river basin. Though, the highest grade for the Milwaukee River in this category only saw water quality goals being met 64.7 percent of the time. That was in the east and west branch.
The Riverkeeper analysts don’t know what’s causing the poor conductivity measurements in the north branch. But they know the land surrounding many of the streams is used for agriculture, and fertilizers that run off from farm fields and into streams during rain showers are loaded with phosphates, nitrates and potassium.
Those same fertilizers are known to be contributing to high levels of phosphorus in the water throughout the basin as well. But, “It’s kind of a complicated parameter,” Nenn notes. Phosphorus enters streams as a “point-source” pollutant, meaning singular or identifiable sources like a sewage pipe draining into the river. But there are several potential point sources around the river basin, including agricultural runoff and effluent discharged from industrial uses. It’s also added to the city water supply to stop lead from leaching out of pipes.
The Riverkeeper analysts see huge discharges in the lower Menomonee River where a lot of factories dump water containing phosphorus into the stream. “If anyone is using city water to cool their equipment and then discharging that water, that water is super high in phosphorus,” Nenn notes.
In general, specific conductivity and phosphorus in streams are common in rural areas with agricultural use. But there’s a third parameter that is also usually found near agricultural land, and that’s bacteria. And bacteria in the river basin is at a failing grade as well.
Phosphorus is called a “controlling factor” for plant and algae growth, according to the DNR. When there are high levels of phosphorus in a stream, growth of aquatic plants and algae can explode. These plants and algae are broken down by bacteria. And agricultural runoff containing bacteria can lead to high levels of bacteria, which consume oxygen to fuel their work. So they end up sucking the oxygen out of the stream, to the detriment of fish and other aquatic life.
In the north branch subwatershed of the Milwaukee River, where Riverkeeper data shows abysmal readings for phosphorus and specific conductivity, the readings for dissolved oxygen are dangerously close to a failing grade. The river basin as a whole, though, received an A- for dissolved oxygen, as the rest of the subwatersheds had good measurements for dissolved oxygen.
The low oxygen results in the north branch could be due to the low flow of a few particular streams, which can lead to stagnant water, but that could be due to the presence of agricultural land surrounding the streams. Driscoll noted that Batavia creek, which had consistently poor oxygen levels throughout the year, is surrounded by agricultural land.
All is not lost, though, Nenn and Driscoll say. There have been cleanup efforts, stream-bed reconstructions and habitat restorations, and there will be more in the future. Many of the problems have been identified, and the Riverkeeper isn’t alone with its monitoring. The DNR and the Milwaukee Metropolitan Sewerage District have decades of data on the state of the river basin, though the Riverkeeper has more monitoring stations than any others.
Nenn says more technology exists now than ever before to identify and deal with water quality problems. But solving these problems is the real challenge, she adds: “What we don’t necessarily have is the money or the political will.”