The Detroit Metropolitan area is predominantly part of two drainage basins.

• Mostly urbanized with areas of high industrialization

• History of automotive and manufacturing industry

• Classified as areas of concern by the Environmental Protection agency (EPA)

• Surface waters negatively impacted by human activities

• Use restrictions of some waters

Rouge River Watershed

The Rouge River watershed consists of approximately 450 square miles that contain more than 1.35 million people residing in 48 cities or towns (1). Water drains into one of the four branches of the Rouge River that ultimately flow the Detroit River. The city of Detroit and much of the surrounding metropolitan area falls within the watershed boundaries . In addition to being heavily populated, the watershed is the most industrialized in southeastern Michigan. The watershed has a legacy of pollution from automotive manufacturing, steel mills, a petroleum refinery, and a coal fired powerplant. Toxic metals such as lead, cadmium, chromium and mercury can be released from these industrial activities. Metals eventually settle and runoff into rivers where they negatively nearby wildlife. Heavy metals can be carcinogenic and disturb neurological function. Communities of fish, amphibians, mammals, reptiles, and insects living in the river are directly impacted by toxic metals. Communities of birds, spiders, and mammals can also be negatively impacted as metals bioaccumulate up the food chain.

The Rouge River watershed is listed as an area of concern by the Environmental Protection Agency (EPA) due to contamination of metals and other aquatic pollutants (2). Impervious surfaces contribute to the runoff of pollutants and also the overflow of untreated or partially treated sewage through combined sewer overflows. Generally, as the amount of impervious surfaces in the watershed increase, the health of aquatic ecosystems decline. The Rouge River Watershed has seen an increase in impervious surfaces over the past 30 years as wetlands, and green spaces have been replaced by roofs, roads, and parking lots (3) . Water does not pass through these surfaces and drains into streams quickly. This quick influx of water can degrade water quality by increasing erosion, raising stream temperatures, reducing dissolved oxygen, and increase turbidity. Higher stream temperatures reduce dissolved oxygen and can exclude sensitive species. Increased turbidity can reduce the rate of photosynthesis and productivity of the aquatic ecosystem. Within the watershed pollutants have contributed to the restriction of fish and wildlife consumption, degradation of wildlife, fish tumors, loss of habitat, eutrophication, and beach closings (2). Eutrophication is caused by excessive nutrient runoff that can lead to algae blooms and lower dissolved oxygen levels. The area has also experienced the following impairments on water quality (3):

• Elevated levels of E. Coli

• Impairment of biota across the watershed

• Dissolved oxygen deficiencies across the watershed

• Polychlorinated biphenyls (PCBs) in fish and surface waters across the watershed

• Mercury in fish tissue and surface waters in some locations

Clinton River Watershed

The Clinton River watershed consists of approximately 760 square miles that contain 1.5 million people residing in 71 cities or towns (4). The watershed is divided into seven smaller sub watersheds, most of which have primarily residential land uses with some areas of industry and agriculture (4). Water that runs into the Clinton River will ultimately flow into Lake St. Clair. Lake St. Clair contains a major shipping channel and is a popular destination for swimming, fishing, watersports and boating and also a source of drinking water. Lake St. Clair is an expansive wildlife habitat and ranks as the 15th largest lake in the country at over 430 square miles (4).

Land use in the Clinton River watershed impacts Lake St. Clair water quality, wildlife, and recreational opportunities. Water quality degradation has largely been due to a history of industrial and municipal discharges, however ongoing water pollution is largely attributed to nonpoint sources (5). Urbanization has played a role in the degradation of water quality as impervious surfaces carry runoff into the river. The urbanization of the watershed has led to the concentration of a variety of pollutants that negatively affect water quality such as, PCBs, heavy metals, solid human waste, and oils (5). Many of these contaminants are associated with cancer in animals and a variety of detrimental effects on the nervous, endocrine, immune and reproductive systems. These pollutants have placed restrictions on fish consumption, caused the degradation of fish and wildlife populations, beach closings and eutrophication. Combined sewer overflows contribute to beach closings, eutrophication, degradation of wildlife populations, and increased levels of fecal coliform bacteria. The watershed has also experienced the following impairments due linked to the decline in water quality (5):

• restriction of wildlife consumption

• decline of bottom dwelling life

• undesirable algae

• loss of aesthetics

• decline of fish and wildlife populations

• loss of aquatic and riparian habitats

Water Gauges to Manage Stream Quality

One technology used to monitor and manage water quality in Detroit and around the country is a network of water gages that measure and publish a variety of parameters. The interview transcribed below summarizes how the technology is used to manage water and preserve its quality for human use and the conservation of aquatic and riparian organisms. Click here to explore the water gage data through the national water dashboard.

Can you tell me about the technology utilized at USGS water gauges to monitor water quality?

The technology used to measure water-quality parameters varies with the constituent being measured. Traditionally, these parameters include: temperature, acidity (pH), dissolved solids (specific conductance), particulate matter (turbidity), dissolved oxygen, hardness and suspended sediment. More recently, nutrient parameters including forms of nitrogen and phosphorus. Some of these instruments emit different light frequencies and monitor the reflected light spectra to measure concentrations of constituents of interest. Acoustic signals are also used to measure things like sediment concentrations. The accuracy of both of these monitoring technologies can degrade over time due to electronic drift in the monitoring equipment and biofouling of the probe. The discrete measurements, which are often based on composite samples that are subsequently analyzed with high precision in a laboratory, provide a basis for detecting and adjusting the continuous measurements.

How is the data used from gauges to manage water quality?

Monitoring data can be used to regulate the discharge of wastewater into a stream. Wastewater commonly has a biological and chemical oxygen demand associated with organic materials. If the oxygen demand and flow rate of wastewater into a stream is too high for the streamflow and dissolved oxygen levels to support, the wastewater can reduce dissolved oxygen levels in the stream to the point that fish and other aquatic organisms cannot survive. Similarly, unsafe levels of dissolved nitrogen in a stream can make the water unfit as a water supply for humans and animals without additional water treatment.

What are the primary challenges of managing surface water quality in urban areas?

Small streams are sometimes enclosed in culverts and are effectively placed underground to reduce their impact on transportation networks and to reduce hazards to urban populations. So, access to streams for monitoring purposes can be restricted. In addition, urban areas typically have large amounts of impervious areas like parking lots, which restrict rainfall infiltration. So, urban runoff tends to occur quickly after the onset of rainfall and is able to carry more debris from humans and animals. In addition, salt for deicing sidewalks and streets can readily find its way into streams.

Are there any new or emerging technologies being used to manage surface water quality in urban areas? If so, can you briefly summarize the implementation of such technologies?

There are technologies to monitor the flow depth and velocity and water-quality parameters in underground pipe networks that commonly carry water to streams. This information can be made available in real time to aid processing and treatment of flows.

What do you think is important to know about surface water quality for people living in urban areas?

Surface waters are less protected from environmental pollution than groundwaters. So, people are commonly able to drink groundwater from wells in suburban and rural areas without treatment. There are many fewer areas, however, where it is safe to drink or come into contact with surface waters without treatment. Also, surface water quality can change rapidly with time and over short distances. Public health officials often post warnings on beaches where elevated bacteria can arise in adjacent surface waters.