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green infrastructure

Stormwater management is all around you. Can you #SpotTheSCM?

realscientistsFor a week in October 2016, I had over 38,000 twitter followers as I took a turn hosting the @realscientists account. Of course, I spent a bunch of my time preaching the gospel of stormwater management. Here are tweets over two days synopsizing its history in 140 character bites. (Please note that the account is hosted by a different scientist each week. The image attached to these tweets is that of the current @realscientists host, not a crazy makeover of Anne.)

On Thursday of @highlyanne’s week @realscientists, she was putting finishing touches on a research proposal to do new, cool science on stormwater managment. She also wanted to get people to realize that stormwater managment is already happening in their neighborhoods, so #SpotTheSCM was born.

Water Management Association of Ohio conference abstract: A Neighborhood-Scale Green Infrastructure Retrofit

I was asked to submit an abstract for the Water Management Association of Ohio conference in November. I’m going to try to sum up 4 years worth of work on the green infrastructure retrofit we’ve been studying in Parma, and I’m looking forward to learning about from the other presenters at this very applied conference.

A Neighborhood-Scale Green Infrastructure Retrofit: Experimental Results, Model Simulations, and Resident Perspectives

Anne J. Jefferson, Pedro M. Avellaneda, Kimberly M. Jarden, V. Kelly Turner, Jennifer M. Grieser

There is growing interest in distributed green infrastructure approaches to stormwater management that can be retrofit into existing development, but there are relatively few studies that demonstrate effectiveness of these approaches at the neighborhood scale. In suburban northeastern Ohio, homeowners on a residential street with 55% impervious surface were given the opportunity to receive free rain barrels, rain gardens, and bioretention cells. Of 163 parcels, only 22 owners (13.5%) chose to participate, despite intense outreach efforts. After pre-treatment monitoring, 37 rain barrels, 7 rain gardens, and 16 street-side bioretention cells were installed in 2013-2014. The monitoring results indicate that the green infrastructure succeeded in reducing peak flows by up to 33% and total runoff volume by up to 40% per storm. The lag time between precipitation and stormflow also increased. A calibrated and validated SWMM model was built to explore the long-term effectiveness of the green infrastructure under 20 years of historical precipitation data. Model results confirm that green infrastructure reduced surface runoff and increased infiltration and evaporation. The model shows that the green infrastructure is capable of reducing flows by >40% at the 1, 2, and 5 year return period, and that, in this project, more benefit is derived from the street-side bioretention cells than from the rain barrels and gardens that treat rooftop runoff. Surveys indicate that many residents viewed stormwater as the city’s problem and had negative perceptions of green infrastructure, despite slightly pro-environment values generally. Substantial hydrological gains were achieved despite low homeowner participation. The project showcases the value of careful experimental design and monitoring to quantify the effects of a green infrastructure project. Finally, the calibrated model allows us to explore a wider range of hydrologic dynamics than can be captured by a monitoring program.

Evaluating Bioretention Cell and Green Roof Hydrologic Performance in northeastern Ohio

Graduate student Laura Sugano will also be presenting her green infrastructure research at the CUAHSI Biennial Symposium in July.

Evaluating Bioretention Cell and Green Roof Hydrologic Performance in northeastern Ohio

Laura L. Sugano*, Anne J. Jefferson, Lauren E. Kinsman-Costello, Pedro Avellaneda
Kent State University


In urban areas, increased runoff from storm events is a significant concern due to flooding, erosion, ecosystem disturbance, and water quality problems. Green stormwater infrastructure is designed to ameliorate these effects by decreasing the flow rate and overall volume of runoff. We compared the effectiveness of a co-located green roof and bioretention cell in order to understand their relative capacities to decrease stormwater runoff, when subjected to the same weather conditions. Our field site was the Cleveland Metroparks’ Watershed Stewardship Center in Parma, Ohio. Beginning in June 2015, rainfall, underdrained outflow, groundwater levels, and soil moisture have been measured on 1-5 minute intervals during 84 storms. Event sizes spanned from 0.25 mm to 54 mm. The bioretention cell completely retained flow from 75% of the storm events, and the green roof retained 49% of storms. The bioretention cell completely retained all events smaller than 3.05 mm and the green roof completely retained all events smaller than 0.51 mm, though some larger events were also completely retained. For storms where underdrain outflow occurred, the average retention was 25% for the bioretention cell and 79% for the green roof. The bioretention cell completely retained 64% of the storm events in summer 2015, 90% in fall 2015, and 77% in winter 2015-2016. The green roof completely retained 37% of the storm events in summer 2015, 48% in fall 2015, and 89% in winter 2015-2016. The groundwater level in the bioretention cell increases in response to storm events and lowers between storms. The soil moisture in the green roof increases during storm events and slowly decreases between storms. My study suggests that bioretention cells can mitigate stormwater issues better than green roofs because they have the capacity to retain more stormwater due to their thicker substrate and their ground-location allows it to retain surface runoff as well as direct precipitation.

The effect of antecedent soil moisture conditions on green roof runoff water quality and quantity

Lab alumna and 2015 REU student Jillian Sarazen is presenting her work this week at the 59th Annual Conference on Great Lakes Research, affectionately known as IAGLR. Jillian graduated from Oberlin College in May. Congratulations on both fronts, Jillian!

The effect of antecedent soil moisture conditions on green roof runoff water quality and quantity.


1. Oberlin College Department of Biology, Oberlin, OH, 44074, USA;
2. Kent State University Department of Biological Sciences, Kent, OH, 44240, USA;
3. Kent State University Department of Geology, Kent, OH, 44240, USA;
4. Kent State University Department of Geography, Kent, OH, 44240, USA.

One of the many benefits of green roofs is that they reduce the amount of stormwater runoff as compared to normal roofs, however they can negatively impact water quality. This study was conducted at the three year-old green roof on Cleveland Metropark’s Watershed Stewardship Center in Parma, Ohio. The objectives were to (1) measure green roof runoff quantity and quality of phosphate (PO43-), nitrate (NO3-) and ammonium (NH4+) concentrations during rain events and (2) relate antecedent soil moisture conditions to water quality and quantity. We sampled sequential water samples (Teledyne, ISCO) during four summer 2015 rain events that varied in size and intensity. We measured soil moisture at high temporal resolution using four logging sensors and two to three times per week at 33 sampling locations using a handheld probe. Soil moisture increased immediately upon commencement of rainfall. Spatial data show a response in the soil to rain events with high variability, but no clear patterns. Phosphate export increased linearly with total outflow, while ammonium and nitrate export did not show clear relationships with outflow quantity. Results of our study show that there is a trade off between ecohydrologic function and water quality, as indicated by leaching of excess nutrients in the green roof outflow.

Keywords: Water quality, Green Roof, Urban watersheds, Green Infrastructure, Lake Erie.

CUAHSI cyberseminars on Urban Streams

Green infrastructure, groundwater and the sustainable city
Larry Band, Institute for the Environment at University of North Carolina

Watershed context and the evolution of urban streams
Derek Booth, Bren School of Environmental Management at UC Santa Barbara

The Little Stringybark Creek project
Tim Fletcher, University of Melbourne

Contaminants of emerging concern as agents of ecological change in urban streams
Emma Rosi-Marshall, Cary Institute of Ecosystem Studies and Baltimore Ecosystem Study

Stormwater-Stream Connectivity: Process, Context, and Tradeoffs
Anne Jefferson, Kent State University

Green infrastructure research featured on Kent Wired

Kent Wired, the electronic version of Kent State University’s student media, ran a story on Saturday about the work Kimm Jarden and I have been doing on the effectiveness of green infrastructure retrofits in a neighborhood in Parma, Ohio.  Hopefully I’ll have more to say about this in the next few days. In the meantime, if you want a glimpse of what we’ve been up to, you can check out the news article here.

Quantifying the influences of stormwater control measures on urban headwater streamflow

The Watershed Hydrology Lab will be at the Geological Society of America meeting in November in Baltimore. Anne will be giving an invited talk in the Urban Geochemistry session (T32) on Sunday, November 1st at 9 am in BCC room 308. Here’s what she’ll be talking about:

Quantifying the influences of stormwater control measures on urban headwater streamflow

Anne Jefferson1, Colin Bell2, Sara McMillan2, and Sandra Clinton3
1. Department of Geology, Kent State University, 221 McGilvrey Hall, Kent, OH 44242 USA. Phone: 1-330-672-2746 Email:
2. Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, Indiana, USA.
3. Department of Geography and Earth Sciences, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, USA.

Stormwater control measures are designed to mitigate the hydrological consequences of urbanization, but their as-built effectiveness in altering patterns of urban streamflow remains poorly quantified. Stream gaging and water stable isotopes were used to understand the effects of stormwater ponds and wetlands on hydrograph characteristics and water sourcing in four urban headwater streams in Charlotte, North Carolina. At the small watershed scale (0.15-1.5 km2), runoff ratio and peak discharge are more strongly related to impervious area than area treated by stormwater controls. For one stream during 10 events, we used stable isotopes to quantify contributions of retention pond discharge to streamflow, taking advantage of the unique isotope signature of pond outflow. The pond, which drains 25% of the watershed’s impervious area, contributed an average of 10% (0-21%) of the streamflow on the rising limb and 12% (0-19%) of discharge at peak flow. During recession, this pond contributed an average of 32% (11-54%) of the stream’s discharge, reflecting the pond’s design goals of temporarily storing and delaying runoff. The isotopic signature of the pond’s discharge also reveals varying water residence times (hours to weeks) within the structure, which may have implications for nutrient and metal fluxes into the stream. Our results suggest that even when individual stormwater control measures are working as designed, they are insufficient to fully mitigate the effects of urbanization on stream hydrology. They also demonstrate the combination of traditional hydrometric and tracer-based techniques can reveal a nuanced view of stormwater influences on urban streams. Such hydrological nuance will be necessary to develop strong mechanistic understanding of biogeochemical processes in urban streams and watersheds.

Abstract: Assessing the Possibilities of the West Creek Watershed Stewardship Center Vegetated Roof

Results of our work on green infrastructure at Cleveland Metroparks Watershed Stewardship Center will make its debut at the CitiesAlive 13th Annual Green Roofs & Walls Conference, in New York, NY from October 5th to October 8th, 2015.

Assessing the Possibilities of the West Creek Watershed Stewardship Center Vegetated Roof

Jessie Hawkins, Reid Coffman, Anne Jefferson, Lauren Kinsman-Costello

The vegetated roof at the Cleveland Metroparks’ Watershed Stewardship Center is an element in a suite of green infrastructure approaches, intended to be educational components, showcasing various methods of stormwater management. This study reviews estimation and design decision making tools to understand expected performance. Field data will be used to assess the current conditions of the roof in order to make recommendations for improvement of the existing vegetated roof system.

The planting design for the roof was intended to intercept rainfall with prostrate vegetation, pre-grown in 4 inch thick trays planted with varieties of Sedum spp. and Allium senescens. Plant species composition and biomass will be assessed in regard to stormwater performance and biodiversity, allowing for an invertebrate habitat. Soil samples taken from the roof have been analyzed for infiltration and nutrient content. Nutrient concentrations will be assessed in rainwater and compared to water flowing off the roof, determining if the roof is a source of nutrients to the downstream ecosystems. Sound reduction and thermal properties will be assessed with the results used for recommendation, serving as a resource guideline for local implementation.

Ground level view of the green roof, April 2015. Photo by A. Jefferson.

Ground level view of the green roof, April 2015. Photo by A. Jefferson.

Post-doc Opportunity in Watershed Modeling at Kent State University

This position has been filled. Thanks for your interest.

Post-doctoral Associate in Watershed Modeling

A post-doctoral position focusing on hydrologic modeling of urban watersheds is available in the Department of Geology, Kent State University, in the lab of Anne Jefferson ( The successful candidate will have experience using RHESSys or another distributed watershed model and interest in applying their skills to questions about the effects of green infrastructure and climate change in urban areas. The post-doc will be expected to contribute to research design and undertaking, publication, and pursuit of external funding. There will also be the potential to develop additional projects building on the strengths, interests, and expertise of the successful candidate. The post-doc will have access to a wealth of data sets, field sites and instrumentation; an interdisciplinary, collaborative group of researchers and external partners focused on urban ecosystems; and a campus mentoring program for postdocs.

Kent State University (, the second largest university in Ohio, is a state-supported, doctoral degree granting institution ranked as ‘high research’ by the Carnegie Foundation. The Department of Geology ( has a strong graduate program (both MS and Ph.D. degrees) in both applied and basic areas of geologic research. The city of Kent combines the eclectic atmosphere of a small midwest college town with easy access to major metropolitan centers, including Cleveland, Akron, Columbus, and Pittsburgh.

Salary will be commensurate with experience and includes a competitive benefits package. Funding is initially available to support 1.5 years of work and opportunities will be sought to extend the support. If you are interested in learning more about the position, e mail Anne Jefferson (ajeffer9 at kent edu) with your CV, a description of your interests and experiences, and contact information for three people willing to serve as references. Review of applications will begin March 1st and continue until the position is filled. Kent State University is an Affirmative Action/Equal Opportunity Employer and encourages interest from candidates who would enhance the diversity of the University’s faculty.