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urban watersheds

Soil moisture dynamics and their effect on bioretention performance in Northeast Ohio

Most members of the Watershed Hydrology lab chose to go to GSA this year, and we had a blast sharing our science and enjoying Vancouver and surrounding areas. But now we are sadly missing out on the American Geophysical Union (AGU) meeting going on this week. Fortunately, a small piece of our work will be represented by outstanding summer REU student Sidney Bush. She’s giving a poster on Thursday afternoon in the Moscone West poster hall at H43F-1017. Here’s her abstract:

Soil moisture dynamics and their effect on bioretention performance in Northeast Ohio

Sidney A. Bush1, Anne Jefferson2, Kimberly Jarden2, Lauren E Kinsman-Costello2 and Jennifer Grieser3, (1)University of Virginia Main Campus, Charlottesville, VA, United States, (2)Kent State University Kent Campus, Kent, OH, United States, (3)Cleveland Metroparks, Parma, OH, United States

Urban impervious surfaces lead to increases in stormwater runoff. Green infrastructure, like bioretention cells, is being used to mitigate negative impacts of runoff by disconnecting impervious surfaces from storm water systems and redirecting flow to decentralized treatment areas. While bioretention soil characteristics are carefully designed, little research is available on soil moisture dynamics within the cells and how these might relate to inter-storm variability in performance. Bioretentions have been installed along a residential street in Parma, Ohio to determine the impact of green infrastructure on the West Creek watershed, a 36 km2 subwatershed of the Cuyahoga River. Bioretentions were installed in two phases (Phase I in 2013 and Phase II in 2014); design and vegetation density vary slightly between the two phases. Our research focuses on characterizing soil moisture dynamics of multiple bioretentions and assessing their impact on stormwater runoff at the street scale. Soil moisture measurements were collected in transects for eight bioretentions over the course of one summer. Vegetation indices of canopy height, percent vegetative cover, species richness and NDVI were also measured. A flow meter in the storm drain at the end of the street measured storm sewer discharge. Precipitation was recorded from a meteorological station 2 km from the research site. Soil moisture increased in response to precipitation and decreased to relatively stable conditions within 3 days following a rain event. Phase II bioretentions exhibited greater soil moisture and less vegetation than Phase I bioretentions, though the relationship between soil moisture and vegetative cover is inconclusive for bioretentions constructed in the same phase. Data from five storms suggest that pre-event soil moisture does not control the runoff-to-rainfall ratio, which we use as a measure of bioretention performance. However, discharge data indicate that hydrograph characteristics, such as lag time and peak flow, are altered relative to a control street. This analysis suggests that street-scale implementation of bioretention can reduce the impact of impervious surface on stormflows, but more information is needed to fully understand how soil moisture of the bioretentions affects inter-storm variability in performance.

Sidney’s poster is part of a session on “Water, Energy, and Society in Urban Systems” that Anne nominally helped convened. Check out all of the stimulating morning talks and awesome afternoon posters on Thursday. The rest of us are sorry to be missing it, but if *you* are in San Francisco at AGU this week, don’t miss out on all the great science in the session.

Stormwater-Stream Connectivity: Process, Context, and Tradeoffs

In a few minutes, I’ll be giving a cyberseminar in CUAHSI’s fantastic sustainable urban streams seminar series. You can join the seminar live at 3:30 pm, or watch a recording of it later. Either way, https://www.cuahsi.org/Posts/Entry/13551 is where you want to go to watch and listen. If you want to know what you’re in for, I’ve attached my late-breaking abstract below. The whole series has been really superb, with great speakers making key points about the state-of-the-science in urban streams and watersheds. I’m honored to be part of the lineup, and I encourage you to check out all of the recordings. Enjoy!

Stormwater-Stream Connectivity: Process, Context, and Tradeoffs

Anne Jefferson

Streams in urban areas are often said to suffer from “urban stream syndrome” resulting in degraded geomorphology, biogeochemistry, and ecosystem function. Uncontrolled or poorly controlled stormwater is a root cause of many of the symptoms of urban stream syndrome, so understanding how stormwater management options affect in-stream processes is important for creating sustainable urban streams. Today’s approaches to stormwater control include green infrastructure distributed throughout the watershed and more centralized stormwater control ponds and wetlands located near the stream. How well do these approaches minimize risks to human health and infrastructure and protect aquatic ecosystems? In this talk, I’ll suggest that the answer depends on three factors: context; process; and tradeoffs. In terms of context, watersheds and stormwater management efforts are situated within a particular natural landscape (climate, soils, etc.); relative to urban development (age and style of development, type of infrastructure); and within the social context of environmental attitudes and economic constraints and incentives. Processes upslope of stormwater controls that affect water quantity and quality and processes within the controls themselves, such as mixing, infiltration and residence time, exert significant influence on how urban stream hydrology, water quality, and ecology responds to stormwater inputs. Where stormwater ponds and wetlands (SCMs) are large inputs to a stream, they can impart distinct water quality signals, and such SCMs are unlikely to restore pre-development stream water quantity and quality. Distributed green infrastructure shows promising reductions in peakflows and total stormwater volumes at the street-scale, but challenges remain in scaling up to enough projects to make a difference at the watershed scale and in ensuring that variability in construction and maintenance don’t reduce the effectiveness of the green infrastructure. Finally, there are tradeoffs in our choices around stormwater management infrastructure, in terms of the broader environmental benefits it can provide versus a more narrow focus on water quantity and quality. Using an ecosystem services framework, I show one approach to examining these tradeoffs. None of the current approaches to managing stormwater are a panacea, but with process-based, contextual studies that also examine limitations and tradeoffs, we can move the science and practice of stormwater management toward better outcomes and more sustainable urban streams.

CUAHSI Cyberseminar Series on Sustainable Urban Streams – featuring Anne + 4 more outstanding hydrologists!

Not in northeast Ohio for tomorrow’s Water Symposium? Don’t worry! There’s lots of urban hydrology coming your way through CUAHSI’s next cyber-seminar series. It starts tomorrow afternoon and extends through December 5th. You’ll hear from four outstanding hydrologists, and then Anne will attempt to have something to add on December 5th.

Sustainable Urban Streams – Science to Support Evolving Management Objectives

The management of urban streams and rivers has historically emphasized two critical ecosystem services: stormwater conveyance (flood protection) and wastewater disposal. Maximizing these services has generally resulted in major alteration of aquatic ecosystem structure and function, and reduced provision of other ecosystem services, such as aesthetics, recreation, food and biodiversity. Recent decades have seen a renewed appreciation of the value of these other services, an improved understanding of the processes by which streams are altered, and the development of engineering and design practices to manage these processes in ways that can provide multiple services.

In this series, we will hear from five presenters:

On Oct. 31 Larry Band will present Green infrastructure, groundwater and the sustainable city, discussing the altered surface and subsurface hydrology of urban areas, and arguing that effective management needs to consider the full critical zone, from rooftop to bedrock. Band is the Voit Gilmore Distinguished Professor of Geography and the Director of the Institute for the Environment at the University of North Carolina.

On Nov. 7 Derek Booth will present Watershed context and the evolution of urban streams, exploring the management implications of different regional and watershed settings on the development and restoration of urban channels. Booth has worked as a geologist and geomorphologist in academia, government agencies and the private sector, including a stint as the president of Stillwater Sciences, Inc., and is an adjunct professor in the Bren School of Environmental Science and Management at UC Santa Barbara.

On Nov. 14 Tim Fletcher will discuss The Little Stringybark Creek project—the world’s first full-catchment retrofit of stormwater infiltration and management practices, which has been in operation and under active study since 2008 under the co-leadership of Fletcher and Prof. Chris Walsh. Fletcher is Professor in Urban Ecohydrology at the University of Melbourne (Australia), and the author of over 300 publications on stormwater quality, treatment and impacts.

On Nov. 21 Emma Rosi-Marshall will present Contaminants of emerging concern as agents of ecological change in urban streams. She will discuss how contaminants such as pharmaceuticals and personal care products can have surprising and sometimes cascading effects on aquatic organisms. Rosi-Marshall is an Aquatic Ecologist at the Cary Institute of Ecosystem Studies and the Director-Designate of the Baltimore Ecosystem Study, one of only two urban long-term ecological research sites in the U.S.

All seminars are at 3:30 Eastern time. For more info, and how to connect, see details here: https://www.cuahsi.org/cyberseminars

On Dec. 5th, Anne Jefferson will present Stormwater-Stream Connectivity: Process, Context, and Tradeoffs, discussing new insights into the downstream effects of conventional stormwater management and green infrastructure practices, how watershed context regulates these effects, and how stormwater-stream management strategies require tradeoffs in the ecosystem services provided by urban watersheds. Jefferson is on the faculty at Kent State University, has had her work funded by NSF, EPA, and USGS, and engages in interdisciplinary collaborations with ecologists, social scientists, and architects.
The series will be hosted by Seth Wenger, Director of Science of the River Basin Center at the University of Georgia.

Kent State Water Symposium Tomorrow: Water Infrastructure and Rebounding Cities

Water Infrastructure and Rebounding Cities

Oct. 31, 2014

8 a.m. – 5:30 p.m.

Kent State University Hotel and Conference Center
215 Depeyster Street, Kent, OH 44240

Tomorrow will be a day full of inter-disciplinary talks and discussion about water and cities. David Sedlak, author of Water 4.0, will be the keynote speaker, but all of the talks promise to be informative and thought-provoking. Watershed hydrology lab students will be showing off their posters in the late afternoon.

Join us for this wonderful and stimulating event. For more info: https://www2.kent.edu/research/water-infrastructure-and-rebounding-cities.cfm

Assessing hydrologic impacts of street-scale green infrastructure investments for suburban Parma, Ohio

The Watershed Hydrology lab will be out in force for the Geological Society of America annual meeting in Vancouver in October. Over the next few days, we’ll be sharing the abstracts of the work we are presenting there.

ASSESSING HYDROLOGIC IMPACTS OF STREET-SCALE GREEN INFRASTRUCTURE INVESTMENTS FOR SUBURBAN PARMA, OHIO

JARDEN, Kimberly, Department of Geology, Kent State University, 221 McGilvrey Hall, Kent State University, 325 South Lincoln St, Kent, OH 44242, kjarden@kent.edu, JEFFERSON, Anne J., Department of Geology, Kent State University, 221 McGilvrey Hall, Kent, OH 44240, GRIESER, Jenn, Cleveland Metroparks, 2277 W Ridgewood Dr, Parma, OH 44134, and SCHAFER, Derek, West Creek Conservancy, Cleveland, OH 44134
Impervious surfaces in urban environments can lead to greater levels of runoff from storm events and overwhelm storm sewer systems. Disconnecting impervious surfaces from storm water systems and redirecting the flow to decentralized green infrastructure treatments can help lessen the detrimental effects on watersheds. Most research on green infrastructure has focused on the performance of individual elements, whereas this project addresses the question of hydrologic impacts and pollution reduction of street scale investments using green infrastructure best management practices (BMPs), such as front yard rain gardens, street side bioretention, and rain barrels. The West Creek Watershed is a 36 km2 subwatershed of the Cuyahoga River that contains ~35% impervious surface. Before-after-control-impact design pairs two streets with 0.001-0.002 ha. lots and two streets with 0.005-0.0075 ha. lots. Flow meters have been installed to measure total discharge, velocity, and stage pre– and post-BMP construction. Runoff data have been analyzed to determine if peak discharge for storm events has been reduced after installation of BMPs on the street with 0.001-0.002 ha. lots. Initial results show that the peak flows have not been reduced for most storm events on the street with the green infrastructure. However, several larger events show that peak flows have been reduced on the treatment street and need to be further investigated to determine what conditions led to flow reductions from these storms but not other events. Initial results for centroid lag-to-peak, centroid lag, lag-to-peak, and peak lag-to-peak show that lag times have increased on the treatment street. Additional research will include analysis of the total effect of street-scale BMPs on storm hydrograph characteristics including, hydrograph recession behavior and total runoff volume. Water samples are being collected at the end of each street during storm events to evaluate the ability of the BMPs to remove heavy metal pollutants from stormwater runoff. After studying the effect of each treatment street, we will define the level of disconnected impervious surfaces needed in order to reduce peak flows within the West Creek watershed.

Stormwater control measures modify event-based stream temperature dynamics in urbanized headwaters

Next week, the Watershed Hydrology Lab will be well represented at the CUAHSI 2014 Biennial Colloquium. We’ll be presenting four posters, so here come the abstracts…

Stormwater control measures modify event-based stream temperature dynamics in urbanized headwaters

Grace Garner1, Anne Jefferson2*, Sara McMillan3, Colin Bell4 and David M. Hannah1
1School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
2Department of Geology, Kent State University, Kent, OH, 44240, USA
3Department of Civil and Environmental Engineering, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA
4Department of Infrastructure and Environmental System, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA

Urbanization is a widespread and growing cause of hydrological changes and ecological impairment in headwater streams. Stream temperature is an important control on physical, chemical and ecological processes, and is an often neglected water quality variable, such that the effects of urban land use and stormwater management on stream temperature are poorly constrained. Our work aims to identify the influence of stormwater control measures (SCMs) of differing design and location within the watershed on the event-based temperature response of urban streams to precipitation in the North Carolina Piedmont, in order to improve prediction and management of urban impacts. Stream temperature was measured within SCMs, and upstream and downstream of them in two streams between June and September 2012 and 2013. Approximately 60 precipitation events occurred during that period. To unambiguously identify temperature increases resulting from precipitation, surges were identified as a rise in water temperature of ?0.2°C between the hours of 15:30 and 5:30, when the diurnal temperature cycle is either decreasing or static on days without precipitation. Surges up to 5°C were identified in response to precipitation events, with surges occurring both upstream and downstream of the SCM under some conditions. Surges were also recorded within the SCMs, confirming that temperature surges are the result of heated urban runoff. Classification tree modeling was used to evaluate the influence of hydrometeorological drivers on the generation and magnitude of temperature surges. In both streams, event precipitation, antecedent precipitation, and air temperature range were identified as the drivers of whether or not a surge was observed and how large the surge was, though the order and thresholds of these variables differed between the two sites. In a stream with an off-line, pond SCM, the presence of the pond in the lower 10% of the watershed did not affect the magnitude of temperature surges within the stream, but the pond itself had a wider range of surge magnitudes than did the stream. In a watershed with a large in-line pond, and a downstream contributing wetland SCM receiving flow from 40% of the watershed, the wetland increased both the frequency and magnitude of temperature surges observed in the stream. Our results suggest dynamic hydrometeorological conditions, SCM design, and position within a watershed all influence whether stormwater management reduces or enhances temperature surges observed within urban headwater streams, and that these factors should be considered in the recommendations for urban stormwater management systems.

Assessing impacts of green infrastructure at the watershed scale for suburban streets in Parma, Ohio

Next week, the Watershed Hydrology Lab will be well represented at the CUAHSI 2014 Biennial Colloquium. We’ll be presenting four posters, so here come the abstracts…

Assessing impacts of green infrastructure at the watershed scale for suburban streets in Parma, Ohio

Kimberly Jarden, Anne Jefferson, Jennifer Grieser, and Derek Schaefer

High levels of impervious surfaces in urban environments can lead to greater levels of runoff from storm events and overwhelm storm sewer systems. Disconnecting impervious surfaces from storm water systems and redirecting the flow to decentralized green infrastructure treatments can help lessen the detrimental effects on watersheds. The West Creek Watershed is a 36 km2 subwatershed of the Cuyahoga River that contains ~35% impervious surface. We seek to evaluate the hydrologic impacts and pollution reduction of street scale investments using green infrastructure best management practices (BMPs), such as rain gardens, bioretention, and rain barrels. Before-after-control-impact design will pair two streets with 0.001-0.002 ha. lots and two streets with 0.005-0.0075 ha. lots. Flow meters have been installed to measure total discharge, velocity, and stage pre– and post-construction. Runoff data has been preliminarily analyzed to determine if peak discharge for large (> 10 mm) and small (<10 mm) storm events has been reduced after installation of BMPs on the street with 0.001-0.002 ha. lots. Initial results show that the peak flows have not been reduced for most storm events on the street with the green infrastructure. However, several larger events show that peak flows have been reduced on the treatment street and need to be further investigated to ensure no outside hydrological impacts are having an effect on the flow. Initial analysis of total flow volume for each event, pre- and post-construction, show that total volume has increased on the street with green infrastructure treatments. Possible explanation for the increase on flow volume could be attributed to under drains from bioretention creating a more connected flow path to the storm drain or an upstream leak in the control street storm drain. Each scenario will be investigated further to confirm results. Further research will include analysis of the total effect of street-scale BMPs on storm hydrograph characteristics including, hydrograph regression behavior and lag time. Analysis on the accumulation of metals in the bioswales and the reduction of metals in street runoff will also be conducted to determine if the BMP treatments are capturing pollutants associated with storm water. After studying the effect of each individual treatment, we will define the level of disconnected impervious surfaces needed in order to achieve a natural hydrologic regime in this watershed.

REU at Kent State – Come work on aquatic-terrestrial linkages in urban ecosystems

Kent State and Holden Arboretum are hosting a summer REU (Research Experience for Undergraduates) focused on aquatic-terrestrial linkages in urban impacted ecosystems. Lots of great faculty in geology, biological sciences and other departments are participating, and I would be thrilled to mentor a student through the program. The program will run from June 1st to August 8th, 2014, and applications are due February 17th.

Kent State University and The Holden Arboretum invite applicants for a 10-week summer research training program. Students enrolled in this program will conduct mentored research into the importance of terrestrial-aquatic linkages in the ecology of urban-impacted ecosystems. This research will be designed to examine how human activities such as urbanization, industry, farming, mining, and recreational activities affect the way terrestrial and aquatic ecosystems interact. Projects might compare sites with and without urban impact to examine: nutrient cycling in soils and streams, microbial community composition in forest soils and stream sediments, plant-soil interactions, how shredders modify terrestrial leaf litter input to stream ecosystems, the effects of terrestrial pollutants on aquatic microbial community structure and function, how terrestrial and aquatic biogeochemical cycles are affected by human activities such as acid precipitation and land-use change. Along with learning about hypothesis generation, project design, and ethics in research, students will receive additional training archiving data in a geospatial database and will participate in weekly seminars.

To find out more about the program, look at all of the possible mentors and cool projects, and begin the application process, check out the website here.

CUAHSI Cyberseminar on Watershed Sensitivity to Climate and Land Use Change

From an email to CUAHSI members today:

A quick reminder that we invite you to join us for a special CUAHSI Cyberseminar this Thursday at a special time hosted by Roy Haggerty,  Tom Meixner, and Patrick Belmont, members of the Water, Sustainability and Climate  (WSC) community.

Thursday, January 23rd, 2 -3 PM ET

Dr. Thomas Johnson

EPA Office of Research and Development

Watershed Modeling to Assess  the Sensitivity of Streamflow, Nutrient, and Sediment Loads to  Potential Climate Change and Urban Development in 20 U.S. Watersheds

Join the seminar at: http://cuahsi.adobeconnect.com/cyberseminar/

Dr. Johnson will discuss the release of the final report released by EPA this fall. From the release:

“There is growing concern about the potential effects of climate change on water resources. To develop this report, watershed modeling was conducted in 20 large U.S. watersheds to characterize the sensitivity of streamflow, nutrient (nitrogen and phosphorus), and sediment loading to a range of plausible mid-21st century climate change and urban development scenarios. The report also provides an improved understanding of methodological challenges associated with integrating existing tools (e.g., climate models, downscaling approaches, and watershed models) and data sets to address these scientific questions. To view the study and related links, visit: http://cfpub.epa.gov/ncea/global/recordisplay.cfm?deid=256912.”

Please join us on January 23rd. Dr. Johnson will present on the results of the report, and there will be a Q&A following the presentation.

Our regular Cyberseminar series will have a spring theme of “Snow Hydrology,” and is being hosted/organized by Dr. Jessica Lundquist (Washington). The spring series begins February 7th. See http://www.cuahsi.org/Cyberseminars.aspx for more info.

Reflecting on Teaching Urban Hydrology – Spring 2013 edition

I was hired as part of a cluster hire focused on urban ecosystems at Kent State University, and while my research has a significant urban component to it, I had not taught an urban-focused class… until this past semester, when I created a new class in Urban Hydrology. Urban hydrology is a fascinating and relevant topic, but its not part of the standard curriculum for geology students in the US. Where urban hydrology is typically taught is at the graduate level to civil engineering students, and follows on courses on hydraulics, fluid mechanics, etc. Thus, the content and approach taken in civil engineering Urban Hydro classes was not quite what I wanted for the senior geology majors and graduate students in my class, most of whom had no experience with hydrology before arriving in my classroom. This class was my first full course taught at Kent State, so it was a big semester of learning about the students here and how to effectively teach to them. While I think my students learned a lot in my class, I can say with some confidence that I learned just as much from the experience of teaching a new topic to a new audience.

At the beginning of my course planning, I set four learning objectives for the students:

  1. Understand the natural and human factors that regulate hydrologic processes in urban areas
  2. Evaluate watershed land use changes and associated hydrologic impacts
  3. Describe methods to mitigate the effects of urbanization on aquatic systems
  4. Analyze the scientific literature on urban aquatic systems and discuss the approaches and main conclusions with fellow scientists and the public

Upon reflection, the first two objectives have some significant overlap, though “evaluation” requires a different set of skills than “understanding.” These two objectives were the primary focus of the first half of the semester, in which I introduced students to the concepts of watersheds, water budgets, and hydrographs, and had them work through the USDA NRCS handbook TR-55 “Urban Hydrology for Small Watersheds” (pdf link) with a real example from the Cleveland metropolitan area. Overall I’m very happy with how this part of the course went, because I took students from not knowing how to define a watershed given a topographic map to being able to solve an applied hydrologic problem in an urban setting.

The first half of the course could also be summed up as “how we got to where we are today in urban watersheds,” and my goal for the second half was to help students understand “where do we go from here.” This is where objectives 3 and 4 came into greater play. We talked about principles and practices of stormwater control and low impact development, stream restoration, solving the legacy problem of combined sewer overflows, and attempts at watershed-scale approaches to reducing stormwater inputs to streams. I organized two optional field trips – one to look at stream restoration and dam removal sites in Kent (with help from the Ohio EPA) and surrounding towns and one lead by Cleveland Metroparks to look at stormwater BMPs and stream restoration in the West Creek watershed in Parma. The culminating project for this half of the class was the design of rain garden. While I’m reasonably happy with how this half of the class went, there are some tweaks I’d like to make for the future. I need to tie the topics covered in the second half of the semester into a more cohesive unit, and I need to rethink my fourth learning objective (re: scientific literature), because I didn’t do as a good of a job as I would like with implementing it. We certainly read quite a number of papers, and they wrote reflective essays about them, but the discussion with the public part didn’t happen.

I’m quite pleased with the final project though. In many neighborhoods, this rainfall that lands on a rooftop is delivered to driveways, streets, or pipes that lead to the storm sewer network and straight to streams. The goal of rain gardens is to “disconnect” the rooftop and treat the water on-site, returning the hydrology to a more natural state. The class worked in teams of three as competing consulting firms angling for a design-build contract on the rain garden. They had to survey the site to quantify impervious surface, soil characteristics, and lot and topographic limitations. Then using a variety of resources that they’d identified for rain garden design and construction, the teams developed plans that detailed size, position, soil characteristics, and planting for the rain garden. On the last day of class they presented their designs to each other. I didn’t actually ask the students to construct the rain garden (that’s something Chris and I have taken on over the summer, since it is in our front yard), but several have asked how the process is going. (I may post some pre-, syn- and post-project pictures later.)

I also had students participate in water quality data collection and analysis for the Cuyahoga River in Kent. I think this was a very valuable way for the students to gain a small amount of experience with hydrologic data from hypothesis generation and testing, to quality control of field measurements, to putting their results in the context of the literature. I’d like to keep a version of this project in future iterations of the course, but I want to tie it more explicitly into the course objectives.

I’m not likely to teach the course again for at least two years, but I’m hopeful that I can build off of what I did last spring to create an even better Urban Hydrology class at Kent State. In the meantime, almost all course materials can be found on my website, which I hope will be a resource for other people interesting in learning more about this fascinating and important field of hydrology.