Assessing the assessment tool: Developing modeling frameworks to evaluate hydraulic fracturing water withdrawals in Michigan
Project leads: Brian Ellis (email@example.com), Avery Demond University of Michigan, Civil and Environmental Engineering
To permit a well for high-volume water groundwater withdrawals, the State of Michigan requires that applicants use an online screening tool, the Water Withdrawal Assessment Tool, or WWAT, to evaluate potential adverse impacts on surface streams. The WWAT was originally designed to permit wells for long-term water withdrawals for purposes such as irrigation, but it is now being used for permitting wells for hydraulic fracturing activities that are characterized by brief, high-volume water withdrawals.
This study assessed the extent to which the analytical solution and assumptions used by the groundwater model in the WWAT provide a sound conservative estimate of streamflow depletion that might result from both traditional and emerging high-volume groundwater withdrawals. The team developed a groundwater flow model using MODFLOW, a 3-D finite difference groundwater flow simulator, at two different locations in Michigan where high volume wells have been permitted. One site was near the Black Creek, in Northern Michigan, a little less than a half-mile from the site of six permitted hydraulic fracturing wells and the other was in Calhoun County in Southwest Michigan where a high volume agricultural irrigation well has been permitted. They then compared the results for streamflow depletion from their model with those estimated by the groundwater model in WWAT.
The team found that the groundwater model used in the WWAT generally provides a conservative estimate of streamflow depletion. However, determining an appropriate value for the stream index flow, which is defined as the lowest flow during the driest month of the year, is paramount to understanding the full potential impact of the water withdrawal, especially for sensitive cold-water streams. In addition, the team found that some elements of the WWAT may lead to less conservative estimates of stream depletion than may have been intended.
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Performance monitoring of green infrastructure sites in Lucas County, Ohio
Project leads: Cyndee Gruden, University of Toledo (firstname.lastname@example.org), Keri Gerwin, Toledo Metropolitan Council of Governments
In 2012, the U.S. EPA Great Lakes Restoration Initiative granted Surface Water Improvement Funds for the design and installation of nine green infrastructure projects in Lucas County, Ohio. Comprehensive and comparable information on green infrastructure performance and costs often creates a barrier to implementing stormwater best management practices. The Water Center supported work by the University of Toledo and the Toledo Metropolitan Area Council of Governments to address this knowledge gap.
Gruden’s research team analyzed ten projects in total, including bioretention, biofiltration, permeable pavement, tree filter, and wetland restoration projects. The project compared design, installation, and on-going management costs for each site, e.g., capital, operations, and maintenance. It also determined how effectively selected green infrastructure projects captured rainwater and filtered soil and heavy metals found in the rainwater. For a subset of sites, the team used stormwater models to gauge project performance under different conditions. These data are available online, and will also be included in the International Stormwater BMP database.
A diverse group of users representing municipalities, agencies, and non-profit organizations from throughout the region met regularly throughout the project period to discuss the research process and advance understanding of green infrastructure projects throughout the region. Many of these partners continue to support green infrastructure work in Lucas County.
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Monitoring ecosystem function responses to stamp sand stabilization in tributaries of Lake Superior
Project leads: Amy Marcarelli (email@example.com) and Casey Huckins, Michigan Technological University
Assessing the success of a stream restoration project typically includes monitoring biotic response over time and comparing measurements in the restored stream to those made in a nearby, healthy reference stream. Ecosystem functions are not typically monitored, despite the fact that they relate directly to biotic responses. This project explored whether measuring stream ecosystem functions, such as nutrient flow through food webs and nutrient cycling within the stream, are useful in understanding overall ecosystem response to restoration activities.
The Houghton Keweenaw Conservation District’s Hills Creek Stamp Sand Stabilization Project, funded by the Great Lakes Restoration Initiative, is using an innovative environmental approach to stabilize and revegetate Hills Creek floodplain habitat buried by legacy stamp sands, tailings from earlier mining activities, in the Upper Peninsula of Michigan. Conducted in collaboration with the Houghton Keweenaw Conservation District, this project added measurements of ecosystem functions – energy flow through food webs, microbial nutrient uptake, retention of particulate and dissolved materials – to enhance understanding of ecological responses to restoration activities.
The research showed that nutrient uptake in restored sections of Hills Creek was similar to the reference reaches, but nutrients uptake was never detected in stamp-sand sites. However, organic matter was retained and decomposed at similar rates across all reference, restoration, and stamp sand sites. The data collected agrees with the results of several other complementary studies in the region– that is, ecosystem processes seem to be resilient to some large-scale stream disturbances as well as restoration efforts designed to mitigate those disturbances. Therefore, they may be less-than-ideal indicators of degradation and disturbance compared to other commonly used indicators such as organism community structure. Moreover, the “best” indicator may be site- and disturbance-specific, which raises concerns about applying a common set of monitoring criteria across large geographic or management units.
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High-resolution orbitrap mass spectrometry is expanding research opportunities related to emerging organic pollutants in freshwater systems
Project lead: Krista Rule Wigginton (firstname.lastname@example.org), University of Michigan, Civil and Environmental Engineering
Using a powerful new instrument, the Thermo qExactive high-resolution orbitrap mass spectrometer (HRMS), University of Michigan researchers are better able detect and quantify organic contaminants and their degradation products in freshwater ecosystems. Organic pollutants of concern in freshwater systems come from a variety of sources, from the breakdown of pharmaceutical and personal care products (PPCPs) to cyanotoxins produced by harmful algal blooms.
Research groups led by Krista Wigginton and Nancy Love (U-M Civil and Environmental Engineering) and Allen Burton (U-M School of Natural Resources and Environment) have been using the new HRMS for about one year, and in that time have focused primarily on methods development for quantifying components of a suite of PPCPs and for building chemical libraries to identify non-targeted chemicals. Over time, there will be opportunities for other University of Michigan researchers to use the HRMS’s broad scanning capabilities to explore a variety of applied freshwater research topics
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