Currently browsing category


Hydrologic response to watershed metrics describing urban development and mitigation with stormwater control measures

Watershed Hydrology lab collaborator and Ph.D. candidate Colin Bell will be giving a talk in T106. From Green Roofs and Gutters to Urban Streams: Advancing Urban Watershed Hydrology through Innovative Field and Modeling Approaches on Monday, 2 November 2015 at 2:25 pm in Room 342 (Baltimore Convention Center).


BELL, Colin D., Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907, MCMILLAN, Sara K., Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907-2093, JEFFERSON, Anne J., Department of Geology, Kent State University, Kent, OH 44242 and CLINTON, Sandra, Department of Geography and Earth Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223,

Stormwater control measures (SCMs) are designed to mitigate changes in hydrologic response to hydrometeorological forcing caused by urban development. Total imperviousness (TI) is a metric that effectively quantifies this urban development, but does not contain information about the extent of SCM mitigation within the watershed. The hydrologic records of 16 urban watersheds in Charlotte, NC spanning a range of TI (4.1 to 54%) and mitigation with SCMs (1.3% to 89%) were analyzed to identify which of a suite of easily-determined watershed metrics best predict hydrologic behavior. We tested the watershed metrics TI, percent forested coverage, impervious area unmitigated by SCMs, effective impervious area, percent SCM-mitigated area, and a newly-developed metric called the mitigation factor. Linear models proved TI to be the best predictor of the 10th, 30th, 50th, 70th, and 90th percentiles of the distributions of peak unit discharge and rainfall-runoff ratios. In addition, TI was the best predictor of a watershed’s ability to buffer small rain events and the rate at which a stream responds once that buffering capacity is exceeded. Additional variables describing hydrograph record flashiness and water yield were best correlated to unmitigated imperviousness and forest coverage, respectively. For the range of watersheds considered, simple metrics that quantify SCM mitigation of both total watershed area and impervious area were neither the strongest primary control nor a consistent, secondary control on storm event behavior across sites. The dominance of TI as a control on hydrology over metrics of stormwater mitigation could either be attributed to the range of sites considered (14 out of 16 sites had less than 20% SCM mitigated area) or because the watershed metrics were not able to consider the spatial arrangement of impervious surfaces and SCMs. Our results have implications for policy makers designing standards that seek to minimize stream ecosystem degradation due to hydrologic disturbances from urbanization.

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.

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.

Brock Freyer defends his MS on the Mighty Mississippi

Two people, standing behind a boat, with river and bluffs in the background.

Brock and Anne at the end of field work on the Mississippi River, July 2008.

Today, Brock Freyer will be defending the results of his M.S. research. The title of his research project is: Fluvial Response to River Management and Sediment Supply: Pool 6 of the Upper Mississippi River System, Southeastern Minnesota.

Brock’s committee is composed of Anne Jefferson (advisor), John Diemer and Ross Meentemeyer.

The defense is on Tuesday April 23, 2013, at 1:30 pm in McEniry 307 of UNC Charlotte. As Brock is currently located in Alaska, this will be a Skype defense. All are welcome to attend.


In this age of environmental restorations and rehabilitations, the scale and extent of projects have been getting larger and more expensive. In the Upper Mississippi River System (UMRS) the U.S. Army Corp of Engineers (USACE) has begun the task of restoring the negative effects that over a century of river management has incurred. Due to the scale and cost of such projects, it is essential to understand the natural and human processes that have affected the river system. In the UMRS, erosion and land loss are considered the dominant geomorphological trend, but Pool 6 of the UMRS is an exception to this norm. In Pool 6, deposition and land growth in recent decades have allowed the river morphology to begin reverting to its condition prior to intense river management. Through the application of varied chronological data sets within ArcGIS, spatial variations were measured to better understand where and why changes have occurred. A nested study area approach was applied to Pool 6 by dividing it into three scales: a general Pool wide observation; a smaller more in-depth observation on an area of island emergence and growth in the lower pool; and a subset of that section describing subaqueous conditions utilizing bathymetric data. The results from this study have indicated that site-specific geographic and hydrologic conditions have contributed to island emergence and growth in Pool 6. In Pool 6 land has been emerging at an average rate of 0.08km2/year since 1975.  Within lower Pool 6, land has been emerging on an average rate of 18m2/year since 1940. The bathymetric subset has shown that sediments on average have gained 2.41m in vertical elevation, which translates into just under 828,000 m3 of sediments being deposited in 113 years.  By identifying and describing these conditions river managers will be able to apply such knowledge to locate or reproduce similar characteristics within degraded sections of the UMRS. If the observations hold true in other locations, restoration efforts will be cheaper, more self-sustaining, promote natural fluvial dynamics, and ultimately be much more successful.

We are currently preparing a manuscript for publication.

Mackenzie Osypian defends her thesis on stream restoration and transient storage

Woman in stream with PVC pipes (piezometers)

Mackenzie tending to piezometers in one of her streams.

Mackenzie Osypian is defending her MS research in Civil Engineering at UNC Charlotte, April 22nd at 4:00 pm in McEniry Hall 441 on the UNC Charlotte campus. Mackenzie is advised by Anne Jefferson and Sandra Clinton. John Daniels and Jim Bowen are on her committee.

Mackenzie’s research is titled: “Evaluating restoration effects on transient storage and hyporheic exchange in urban and forested streams.”  Her abstract is below:

Millions of dollars are spent each year on restoration projects designed to improve stream habitat, but few studies have investigated effects of restoration on groundwater- surface water interactions. Hyporheic exchange and transient storage in four second-order streams (urban/forest; restored/unrestored) were studied by measuring geomorphology, streambed vertical head gradients and water fluxes, and by using conservative, impulse-loaded tracer studies along with the OTIS model. Total storage exchange and percent hyporheic exchange were found by utilizing the OTIS P parameters and the sum of downwelling fluxes calculated in SURFER. The upwelling and downwelling varied between -1.783 m/m to 3.760 m/m in the restored urban stream, which contains large step structures, while the unrestored urban stream had no measured upwelling or downwelling (0 m/m) along the reach, which is incised to bedrock.  The forested restored stream had a smaller range of hydraulic gradients (-0.012 m/m to 1.99 m/m) compared to the forested unrestored stream, which ranged from -0.725 m/m to 0.610 m/m. The forested unrestored reach had the highest percent of hyporheic exchange, reaching 22% during the winter season. The urban restored has the smallest percent of hyporheic exchange of 0% across all seasons due to the exposure of bedrock in the streambed. The restored reaches were found to have between 0% and 6% of total transient storage exchange occurring in the hyporheic zones, with some seasonal variability.

The results indicate that restoration increases the hyporheic storage when the stream has incised to bedrock, but that large in-channel storage is also created. When the stream has an alluvial bed (as in the forested streams), the percent of hyporheic flow compared to total storage is reduced. The forested unrestored stream had the largest average hydraulic conductivity of 0.006 cm/s compared to the forested restored, 0.001 cm/s, and the urban restored, 0.001 cm/s.  The restored forested site had a maximum area to storage area ratio of 247 m2/m2 in the spring, which was higher than the forested unrestored site. That site had a maximum of 16.4 m2/m2, which occurred during the fall season.

We are currently preparing her thesis for publication.

Reflecting on my cities and their water

This week’s mini-assignment for my urban hydrology class reads thus: “In 1-2 paragraphs, describe your hometown (or some other city you know well) in terms of its location, size, and form and why it is that way (i.e., historical context). Then write a paragraph describing your city’s relation to water. For example, what is the water supply and where is wastewater disposed? Are there local water bodies or water issues important to the community? You don’t need to include references with your assignment, but you should check your facts if you are unsure about anything.”

Because I’m a water geek, and I wanted to model a good response to these questions, I present not one, but two, reflections on cities I’ve known well and how those cities relate to water.

Winona, Minnesota

I grew up in Winona, Minnesota, a town of about 28,000 people in the southeastern corner of Minnesota. The main part of the city is situated in the middle of the Mississippi River floodplain, with the main channel on one side and a former channel (now lake) on the other. The Winona area was inhabited by Native Americans for millennia, prior to its establishment by white settlers in 1851. Winona’s location along the river made it an important link for railway and steamboat transportation, and Winona was the second place on the Mississippi to be crossed by a railroad bridge (opened in 1891). Winona grew rapidly, and by 1900 had almost 20,000 residents. Winona was a major sawmilling center (with logs floated down the river to the mills), and Winona is still a major port on the river for loading agricultural products onto barges. In southeastern Minnesota, the Mississippi River sits in a ~500 foot deep valley, so as the city has grown larger, it has spread outwards into tributary valleys and up onto the plateau. However, most of the population still lives on the floodplain, and most of the developed area (including pretty much all of the industrial and commercial areas) is in the valley bottom.

As is apparent by the paragraph above, Winona as a city is intricately tied to the Missisisippi River, physiographically and economically. River recreation (boating, fishing, duck hunting) is also a major past-time (and economic contributor) for Winonans. The river holds pride of place in town, but it was also a source of major and frequent flooding until 1985 when an 11-mile levee was built surrounding the town. Other than the occasional flood (now more a curiosity than a catastrophe), periodic public engagement with dredging of sand from the river bottom, and the enjoyment of boat trips on the river, I would say that Winonans’ aren’t particularly attentive to water issues, because it is abundant and out of their way. The city gets its water supply from a Cambrian sandstone aquifer several hundred feet below town, where water is abundant and good quality. It disposes its treated wastewater into the river at the downstream end of town. The big water issue I remember growing up, was about water quality in the Lake, which was quite degraded by the invasive exotic, Eurasian water milfoil. There is actually a water issue that has cropped up over the last several years in the region, which is getting local attention, and that is the mining of “frack sand” from the local sandstone formations. This is getting attention because of problems with heavy truck traffic in town, blowing sand from exposed storage piles, and from destruction of rural areas where the sandstone is being mined. However, to me, it is ultimately a water issue, because those sandstone formations are the regional aquifers. It’s not clear to me yet what effect the mining will have on local or regional water quality, but it seems like an issue to watch.

Charlotte, North Carolina

I spent five years living in Charlotte, which is the largest city in North Carolina, with a metropolitan population of 1.8 million people. Charlotte is a major financial center, and also the home of NASCAR. The city was founded around 1755 at the intersection of two Native American trading paths, and it was a “hornet’s nest of rebellion” during the American Revolution, being the first place that city leaders signed a declaration of independence from Great Britain. Charlotte’s history includes being close to the site of the first gold boom in the US, and becoming a major cotton processing center and railroad hub. Banking and NASCAR rose to prominence since the 1970’s, and the region has experienced explosive population growth (and urban sprawl) since then. The population of the city itself has gone from 241,000 in 1970 to over 730,000 in the 2010 census. There is a relatively small, high density city center surrounded by miles of low density residential, commercial, and industrial development. The gentle rolling topography of the Piedmont forms no barriers to the geographic expansion of the urban area. Several small towns have been agglomerated by the urban area, and many people commute from these communities into the city center or across the city.

The Catawba River, which has a watershed area of 3343 miles upstream of the South Carolina border (Charlotte’s southern boundary), flows through the urban area a few miles west of downtown Charlotte. The River is impounded in a series of reservoirs used for hydroelectric generation by Duke Energy, and was one of the first rivers in the country used for that purpose. Most of the land along the river is privately owned by relatively affluent people, and there are only a few public parks on the reservoirs. Power-boating recreation is popular with those along the river, but swimming is banned in the county in which Charlotte sits, because of concerns about liability. The river forms the water supply for the city, because the fractured crystalline rocks in the area don’t support pumping of large groundwater volumes. Wastewater is treated and disposed of back into the river (farther downstream) or into local streams. There are a number of small urban streams that flow through the city, and these streams are quite prone to flooding during heavy rainstorms. The city and county have undertaken a major stream restoration and stormwater management program to try to reduce flooding hazards, and a series of greenways have been established along the some of the streams. When I moved to Charlotte in 2007, we were in the middle of an intense drought, and subject to limitations on outdoor water use. However, as soon as the drought lifted, local water conservation mindfulness seemed to disappear too. There is an illusion of abundance of water in the southeastern US, even though as population grows water supplies are becoming stressed (Atlanta is a stark example of this). In a recent book, author Cynthia Barnett highlighted Charlotte as a prime example of a city that was “disconnected” from its water supply, meaning that the people of the area lacked a water culture or ethic that would encourage conservation and sustainable use.

I probably spent about 20 minutes writing each piece, but I’m fairly familiar with the water issues and setting in each area (see above: I’m a water geek). So it might take you a bit longer to do a similar amount of writing. One essay is 499 words, and the other is 528 words, but you could write less and still cover the relevant information. I haven’t included hyperlinks to lots of sources here, because I didn’t require that of my students, but I might go back later and add them, because it just seems like wasting the capabilities of the web to not do so.

Anne’s November Navigations

Cross-posted at Highly Allochthonous

I’m not joining the exodus of geoscientists to AGU this week; I’m still recovering from November.

I’m not sure whether I spent more time in Ohio or outside of it last month. The month started with the rain and runoff from our brush with Superstorm Sandy, but by November 2nd I had a car packed full of conference and research gear and was heading south to North Carolina. The drive south was a great chance to watch all sorts of geology go by at interstate speeds. I started out in the glaciated Appalachian Plateau, drove south of the glacial limit, crossed the Ohio River, and was soon in the heart of the Appalachians and West Virginia‘s coal mining country. On Interstate 77, the border between West Virginia and Virginia seems to mark the dramatic transition the Valley and Ridge Province, then it is up on to the Blue Ridge and finally down the Blue Ridge Escarpment and into the Piedmont and North Carolina, finally arriving in Charlotte after eight hours of driving. Climatically, I left the cold and damp, drove through the snow left behind by Sandy, and ended up in the warm, sunny, and very dry south.

The Geological Society of America meeting was a busy time. I convened two sessions, helped lead a field trip and had more meetings for committees and with colleagues than I care to remember. But it was a great time to hear about exactly the sorts of science that I find most interesting and to get out in the field with 50 friends and colleagues to talk about new ideas in geomorphology.

  • Geomorphology of the Anthropocene: The Surficial Legacy of Past and Present Human Activities. We had an amazing slate of speakers that packed the room, fantastic poster presenters that drew a crowd, and we were able to announce that we will be editing a special issue of the new journal Anthropocene with papers from the session. Then the journal’s publisher threw us a special reception.
  • Hydrology of Urban Groundwater, Streams, and Watersheds. This session featured another roster of incredible speakers and a kick-ass set of posters featuring many of my students and colleagues from UNC Charlotte.
  • Kirk Bryan Field Trip: Piedmont Potpourris: New Perspectives on An Old Landscape (and Some of its Younger Parts. The annual syn-meeting field trip of the Quaternary Geology and Geomorphology division always features good scenery and intense but friendly discussions. This year we looked at an old mill dam site in an urban stream and channel heads and terrace soils near the Catawba River, and then we climbed a monadnock to talk about Blue Ridge escarpment retreat and the long term evolution of landscapes. Plus, we had a delicious lunch of NC barbecue on our able and charismatic field trip leader’s front lawn.

Missy Eppes atop a red soil pit.

Field trip leader Missy Eppes atop a typically red soil profile, on a terrace above the Catawba River.

50 geomorphologists on the front steps

An enthusiastic and well fed group of geomorphologists and Quaternary geologists on a delightful November day.

Geomorphologists on a rock listening to Ryan McKeon

On top of Crowders Mountain, learning from Ryan McKeon.

After the meeting was over, I stuck around Charlotte for a few days, with plans to do a tracer injection in one of my local field sites. As I’ve already shown you, that didn’t work out so well. So I headed back north.

Back in Ohio, I did some exploring of Cuyahoga Valley National Park, which was timely given that I am just about to submit a proposal to do work in the headwater streams in and around the park. I also spent a wonderful day with someone from the Ohio EPA, looking at dam removal and stream restoration sites in the region.

Stream with sediment and trees

Headwater stream near Brandywine Creek, CVNP, November 2012.

My fun explorations of Ohio streams were tempered with sadness though. Just before Thanksgiving, my sweet, 14-year old canine companion, Cleo passed away. She was my longest running and most faithful field assistant, and I’ll miss her forever.

Dog meets spring

Cleo, in ~2005, at one of my PhD field sites.

But then it was off to Baltimore to visit with Claire Welty and the folks at the Center for Urban Environmental Research and Education, who do some of the coolest urban hydrology work around. They also host the Baltimore Ecosystem Study field site.

Sign on door reads "Baltimore Ecosystem Study"

That was just the warm-up for the real reason for my trip, giving a seminar in the Department of Geography and Environmental Engineering at The Johns Hopkins University. My talk was on “drainage network evolution is driven by coupled changes in landscape properties and hydrologic response,” in which I attempted to integrate the Oregon Cascades, North Carolina Piedmont, and urban landscapes. It was a thrill and an honor to give a Reds Wolman seminar at JHU, which is my undergraduate alma mater, and the experience was made even more memorable by a morning spent exploring stream restoration sites with Profs. Peter Wilcock and Ciaran Harman. We saw some sites that made some sense, and some that were a bit…non-sensical? I will come out and say it, I’m not a fan of what happened to the little granite pegmatite knickpoint where I went as an undergraduate to try to pretend I wasn’t really in the city. But a bit farther upstream, I could see the value in installing some nice structures that stabilized banks and increased accessibility to the stream in a park popular with joggers and dog-walkers.

JHU profs Wilcock and Harman discuss the restoration of Baltimore's Stony Run

JHU profs Wilcock and Harman discuss the restoration of Baltimore’s Stony Run

And that pretty much brought me to the end of November. I’m looking forward to no travel in December, at least until the end of the month. But that doesn’t mean I won’t stay busy.

The wrong conditions for a stream tracer injection

Cross-posted at Highly Allochthonous

Leaving behind Ohio and the high waters from Sandy, I ventured south in early November for the Geological Society of America meeting in my former home of Charlotte, North Carolina. The meeting was busy and wonderful, and far too packed for me to hear as much science or talk to as many people as I would have wished. After the meeting was over, I stuck around Charlotte for a few days in order to do some field work with one of my graduate students. Our plan was to do a tracer injection in one of the headwater streams that form her field area. Such tracer injections are a bit finicky to schedule…if it’s raining or has recently rained, you can’t do them because the stream discharge won’t be steady over the several hours of the experiment. But Sandy had not dropped any rain on the Charlotte area and the weather was beautiful all during the conference. Nonetheless, my student assured me that there would be plenty of water in the stream, as it had been running well just two weeks prior. Perfect conditions, we thought.

So the afternoon before the experiment, we headed out to the study site to measure discharge and mark the places where we would be collecting samples. My student advised me to wear my hip waders, not knee boots, as she had over topped her boots last time she was in the field.

But…it turns we didn’t need the boots. At all.

Piezometers rising from a dry stream bed.

The wrong conditions for a stream tracer injection, November 2012, Charlotte, NC.

Clearly, we could not add our tracer to the streamflow the next day. We were missing one crucial ingredient: streamflow.

One upside to the situation is that it was a very easy call to make. No hemming and hawing and making some sort of judgement about whether things were “good enough” to go for it. We simply couldn’t do the experiment.

It was also stunningly good conditions for walking the channel and looking at the location and conditions of the stream restoration structures and wood jams. And we spent the next day with our heads together working on much more solid plans for the eventual experiment. So, not a total loss.

But now we need to wait, for the right hydrological conditions, suitable ecology, and a time that works in our schedules. Field work is incredibly important for learning about the way that real, complex hydrologic systems work. And it can be incredibly fun. But it can also be filled with frustration…and waiting. In this case, for the “right conditions for a stream tracer injection.”

Abstract: Evaluating the success of urban stream restoration in an ecosystem services and watershed context

I’ll be at the 2013 Upper Midwest Stream Restoration Symposium in LaCrosse, Wisconsin in February. Even though the conference focuses on the Upper Midwest (of which Ohio is a part), I’m going to be talking about work from the southeastern US. Of course, the conference will be a great chance for me to learn from and make connections with stream restoration practicioners and scientists in the Midwest. I’m really looking forward to it, and hopefully they won’t call me out as a carpetbagger. I actually grew up ~25 miles from the conference location.  Here’s the abstract.

Evaluating the success of urban stream restoration in an ecosystem services and watershed context

Anne Jefferson1, Sandra Clinton2, Mackenzie Osypian3, Sara McMillan3, Alea Tuttle2

1. Department of Geology, Kent State University
2. Department of Geography and Earth Sciences, University of North Carolina at Charlotte
3. Department of Civil Engineering, University of North Carolina at Charlotte

In urban watersheds, the capacity of streams to provide essential ecosystem services is often limited as a result of channel straightening, incision and removal of geomorphic features. Stream restoration seeks to provide stream stability while reestablishing ecosystem services, but restoration alone may not mitigate the effects of watershed land-use change and urbanization. Stream restoration activities frequently impact transient storage and hyporheic exchange, the processes by which water movement is slowed down or temporarily detained at the surface or in the streambed. Transient storage and hyporheic exchange zones are important regulators of nutrient retention and stream temperature, and they harbor diverse biological communities. However, it is unknown how successful stream restoration activities are at creating ecologically effective storage and exchange zones that promote improved water quality and nutrient retention. In a series of studies in Charlotte, North Carolina, we have evaluated restored and unrestored streams to quantify and compare transient storage and nutrient retention. Our goal is to evaluate the relative success of restoration activities for ecosystem services in urban and forested watersheds. We measured increased transient storage and greater variability in upwelling and downwelling vertical hydraulic gradients in restored relative to unrestored reaches. However, restored reaches also had lower hydraulic conductivity of bed sediments, which was likely related to to restoration practices such as streambed compaction and installation of landscaping fabric and cement below structures that may reduce the magnitude of hyporheic exchanges. Restored streams also have higher water temperatures than unrestored streams. The removal of riparian vegetation and soil disturbance and compaction during the restoration process, along with continued input of nutrients from fertilizers in urban watersheds can result in a unique water quality signature in urban restored streams. Denitrification rates were variable between sites, but channel complexity and restoration of urban streams appear to increase denitrification, even though hyporheic exchange was generally low. In unrestored urban streams, allochthonous anthropogenic debris (e.g., shopping carts) may contribute to channel complexity and nutrient retention. While current practices of urban stream restoration may be successful in creating channel stability, coupling watershed-scale management of stormwater and nutrients with restoration techniques designed to enhance ecologically effective storage and exchange may be required for restoration success in a holistic sense.

Dense riparian vegetation, dry stream channel, rocks, log, and a muddy pool

One of our restored stream sites, during the summer drydown (August 2010). Beaverdam Creek watershed, Charlotte, North Carolina. Photo (c) Anne Jefferson.

Positions Available: Urban Hydrology and Water Quality Research Assistants at UNC Charlotte

Join the exciting Ecology and Biogeochemistry of Watersheds research group at UNC Charlotte in learning about the effects of stormwater management on urban stream ecosystems.  We are looking for one or more student research assistants for full or part-time work. This is a great opportunity for students looking for hands-on research experience and will be a good resume boost for those intending to go to grad school.

The research assistant will be responsible for helping with some or all of the following:

  • Maintaining field equipment including autosamplers, water level loggers, and temperature probes
  • Collecting discharge (streamflow) data and water samples during and following storms and wet weather
  • Assisting with sediment, water and biological sampling in the field and lab
  • Assisting with laboratory tasks, including sample preparation and analysis
  • Maintaining instrument logs and good records of field and laboratory measurements

We are searching for students interested in part-time or full-time work for the summer. There is also the opportunity to begin work immediately and continue into the next academic year on a part-time basis. Your summer schedule should have enough flexibility to allow you to participate in field work as weather conditions dictate. You must provide your own transportation to and from field sites, but you will be reimbursed for gas. Research assistants will be paid $10/hour.  While desirable, previous experience is not required for these positions.

To apply for these positions, please email your (1) resume, (2) list of relevant coursework,  (3) list of past field and research experiences, and (4) availability for full-time or part-time work in the spring, summer and fall to Sara McMillan (smcmillan at uncc dot edu), Anne Jefferson (ajefferson at uncc dot edu), or Sandra Clinton (sclinto1 at uncc dot edu).  Incomplete applications will not be reviewed.  If you have questions about the work, please email us before applying. You can learn more about our group here:

We will begin considering applications immediately.

Muddy Creek: A restored urban stream and one of our field sites