Read more about our work on climate change and waterborne disease National Geographic News
Milwaukee River Plume Project
Turbid water plumes are frequently observed in the Milwaukee harbor and Lake Michigan following large rain events. Understanding the impact that these plumes have on the nearshore environment is important for protecting Milwaukee area beaches and prioritizing mitigation efforts. Additionally, Total Maximum Daily Load regulations require that the Milwaukee River watershed substantially reduce total loads of fecal bacteria, sediments, and nutrients to Lake Michigan. In part of a study funded by the Milwaukee Metropolitan Sewerage District, we aimed to better understand the fate of some of these pollutants associated with wet weather events using a previously constructed hydrodynamic model. This model was originally developed in collaboration with Prof. Hector Bravo to visualize both spatial and temporal dynamics of fecal coliform concentrations in Lake Michigan. For this project, we collaborated with Prof. Bravo and Dr. Bahram Khazaei to adapt and expand upon the model so that we could explore differences between the “visual” plumes caused by suspended sediments and the “invisible” plumes caused by fecal bacteria (fecal coliform and E. coli).
The hydrodynamic model animations below show movement of pollutants in the Milwaukee harbor and nearshore during the same rain event (the event dates can be seen at the top of each animation).
Hydrodynamic model of fecal coliform impact in the Milwaukee nearshore from a June 2018 rain event
Hydrodynamic model of Total Suspended Solids impact in the Milwaukee nearshore from a June 2018 rain event
World Harbor’s Project
Our lab is collaborating with the World Harbor’s Project to understand pollution signals and other worldwide challenges that major harbors face. This work involves tracking a number of indicators to understand the broad health issues that impact global waterways adjacent to urban environments.
Oceans and Human Health
Sewage overflows are a serious public health threat in the Great Lakes. The EPA has previously estimated that 850 billion gallons of combined stormwater and sewage from older cities is discharged into surface waters. Almost one fifth of these communities are in the Great Lakes, which has approximately 10,000 miles of shoreline and serves as drinking water to more than 40 million people. This pollution contains human pathogens that can potentially impacts drinking water intakes and the more than 500 beaches within the US boundaries. Our project is an interdisciplinary project focused on coupling hydrodynamic modeling and particle distribution studies with molecular detection of to predict pathogen fate in the Great Lakes. Recent findings from our work have shown that viruses and other pathogens are present at detectable levels following rain events that introduce stormwater into nearshore waters of Lake Michigan. Levels of fecal indicator bacteria increase an order of magnitude (e.g. ten times) following severe storm events and combined sewer overflows. Pollution plumes are rapidly diluted once they extend more than 2.5 km offshore, however evidence of pathogens can be found using molecular methods as far as 8-10 km into open waters.
This project is in collaboration with Hector Bravo’s work with hydrodynamic modelling and Val Klump’s work on determining particle residence times and sediment resuspension in the system.
Former students in our OHH training program
Identification and Quantification of Sewage Contamination in the Milwaukee Estuary Area of Concern
In work funded by a WDNR/EPA Area of Concern (AOC) grant, we demonstrated that human fecal contamination is chronic in the urbanized rivers of metropolitan Milwaukee. The use of fecal coliforms and other culture-based fecal indicator bacteria alone fail to identify the risk of human sewage contamination in recreational waters, as demonstrated by the inconsistent detection of human fecal indicators among samples that had both high and low fecal coliform concentrations. The results are being applied to local TMDLs which must take into account the sources of fecal contamination before informed decisions can be made for implementation. Additionally, we examined loads of human fecal pollution entering the Milwaukee estuary during different hydrographic events. Fluxes of sewage in Milwaukee’s three rivers increased several orders of magnitude between low flow periods and rainfall events, suggesting rainfall was a driver of sewage pollution. Sewage contamination in these rivers related to the degree of urbanization in the watershed indicating that there are consistent sources of sewage throughout the urban areas.
CDC/Wisconsin Department of Health Services
Through our work on the Health Impact Assessment of Climate Change in Wisconsin project, we collaborated with a research team (Jonathan Patz and Steve Vavrus from University of Wisconsin Madison) with expertise from across the fields of climatology, environmental public health, water resources, microbiology, and statistical modeling to develop a state-level health impact assessment of climate change in Wisconsin. A primary goal of this work is dissemination of our findings to inform future policy and decision making. Ten policy briefs are available for download through the link above.
WICCI
The Wisconsin Initiative on Climate Change Impacts (WICCI) is a joint effort between the Department of Natural Resources and the Nelson Institute of Environmental Studies at the University of Wisconsin-Madison. This effort includes several working groups throughout the state of Wisconsin. The Milwaukee Working Group started in February 2008 as a multidisciplinary approach to address the impacts that climate change will have on the most urbanized area in the state of Wisconsin and Lake Michigan. The goals of this working group are to (1) organize a critical mass of researchers, professionals, and policy makers that span a wide range of disciplines (e.g., water resources, hydrology, public health, engineering, urban planning, economics); (2) explore the impact of recent climate changes on the urban environment and relevant infrastructure (3) detail how future climate change is likely to influence the Milwaukee urban environment, and (4) formulate recommendations for adaptive management strategies.
WICCI completed its first assessment report, including reports from the Milwaukee working group and the 12 other groups http://www.wicci.wisc.edu/publications.php.
NOAA/SARP (Download the 2013 Final Report)
Climate Change Risks and Impacts on Urban Coastal Water Resources in the Great Lakes. Recently, the Milwaukee Working Group was awarded the NOAA Sectoral Applications Research Program (SARP) grant to incorporate climate change data into existing water resource models so decision-makers can evaluate future risks and consequences to the Milwaukee metropolitan area, including nearshore Lake Michigan, a values resource for the region.
The primary focus of this project is to characterize the water resource and coastal impacts and consequences of altered climate patterns in the Great Lakes.
Example of downscaled climate data for the State of Wisconsin. Downscaling global climate models improves resolution at a regional scale, allowing finer scale predictions that are specific to Southeastern Wisconsin.
Source: David Lorenz, Nelson Institute Center for Climatic Research, University of Wisconsin-Madison
For more information see the Interagency report on The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment