Currently browsing category


GSA abstract: Abundance and Geomorphic Function of Wood in Urban Stream Systems

Later this month, Caytie, Garrett, and I will be representing the Watershed Hydrology Lab at the Geological Society of America Annual Meeting in Seattle, Washington. Garrett will be presenting the following talk on Monday at 2:55 in Conference Center Chelan 5.

Abundance and Geomorphic Function of Wood in Urban Stream Systems

Blauch, G. and Jefferson, A.

Large wood serves important geomorphic and ecologic functions in streams, as established by research set in relatively undisturbed watersheds. However, the dynamics and function of wood in urban streams has not received similar attention. Previous studies have not clearly distinguished between the effects of low recruitment potential due to developed riparian zones and hydrograph flashiness increasing wood mobility. In order to focus on the effects of hydrograph flashiness, our study focuses on wood abundance and function across urban northeastern Ohio streams where protected riparian buffers offer recruitment opportunities. Impervious surface cover is used as a proxy for urbanization’s effect on the stream hydrology. The frequency and geometry of large wood was surveyed within the bankfull channels in 11 stream reaches, with watersheds that span 0.39 – 88 km2 and 0.56 – 40.1% impervious cover. Geometry measurements cover length, diameter, and planform orientation for individual pieces and smaller jams, as well as 3D structure of significant wood jams in 7 of the 11 streams using Structure-from-Motion techniques. Measurements of the long profiles, stream banks, and streambed sediments provide indications of the geomorphic context of large wood with respect to pool formation, bank erosion, and sediment storage. Preliminary results show a decrease in the occurrence of large wood pieces from 36 per 100m of stream length in the least developed watershed to as little as 1 piece per 100m at higher impervious surface covers. Of those streams with wood stored as both individual pieces and as part of jams, 73% of the total wood (by count) is stored as jams on average. In the most developed, urban watersheds, early re-surveys show that even these larger jams can be mobilized. These results suggest that even though wood is available to the stream, flashy urban hydrographs still have an influence on the presence of wood within urban streams. With large wood often considered in management and restoration practices, protection of the riparian buffer is not enough to maintain the presence of wood – and the geomorphic and ecologic benefits provided by it – in these flashy urban systems.

wood jam spanning a stream, man on right side gravel bar looking at something in his hands.

Garrett get ready to take some data on this wood jam in West Creek, August 2017.

GSA abstract: Storage Dynamics Revealed by Water Isotopes Provide Insight into Water Quality Function of Stormwater Green Infrastructure

Later this month, Caytie, Garrett, and I will be representing the Watershed Hydrology Lab at the Geological Society of America Annual Meeting in Seattle, Washington. I will be presenting the following talk on Wednesday at 10:15 in WSCC Room 612.

Storage Dynamics Revealed by Water Isotopes Provide Insight into Water Quality Function of Stormwater Green Infrastructure

Jefferson, A., Sugano, L., Buzulencia, H., Avellaneda, P., and Kinsman-Costello, L.

Increasingly popular, stormwater green infrastructure is touted as improving water quality, through filtration and retention that allows plant uptake and biogeochemical processing to occur. Many data sets reveal large inter-storm variability of water quality in green infrastructure effluent, suggesting that internal dynamics that control water transit time may play an important role in the water quality functioning of green infrastructure. We hypothesized that collecting data on water stable isotopes, in addition to solute chemistry, would provide insight into transit times and would help explain variability in water quality flowing out of three forms of green infrastructure. Water isotopes, chemistry, and fluxes were measured from bulk precipitation, inflow, outflow, and surface water storage for a green roof, bioretention cell, and wetland at a site in northeastern Ohio.

On the green roof, outflow isotopes were variable within storms, but flow-weighted averages were similar to bulk precipitation for each event, suggesting transit times of minutes to hours. First flush behavior for solutes was exhibited for some storms and some solutes, but much of the inter-event variability in solute export could be explained by precipitation amount and antecedent dry period of each storm. In the bioretention cell, inter-event storage and release of old water is sometimes observed in the outflow isotopes. Outflow nitrogen concentrations were generally lower when old water was discharged, suggesting that denitrification is occurring within the bioretention cell. However, antecedent dry period also appears to influence nitrogen concentrations, suggesting some discharge of new water even during moderately-sized storms. Isotopic hydrograph separation was possible for some storms in the wetland, and in these cases, solute concentrations in the outflow can be explained by mixing of new water with previously ponded water. Where solute concentrations can’t be explained by mixing, biogeochemical processing may be happening during the storm period.

This work builds on work I presented earlier this year at the HydroEco 2017 (June) and the GSA regional meeting (March).

GSA abstract: Soils and Geomorphology of Five Reclaimed Surface Mine Sites in the Cuyahoga Valley National Park, Ohio

Later this month, Caytie, Garrett, and I will be representing the Watershed Hydrology Lab at the Geological Society of America Annual Meeting in Seattle, Washington. Caytie will be presenting the following poster on Tuesday, October 24th in spot 257-4 in the Washington State Convention Center.

Soils and Geomorphology of Five Reclaimed Surface Mine Sites in the Cuyahoga Valley National Park, Ohio

Ruhm, C., Jefferson, A., Blackwood, C., Minerovic, A., and Davis, C.

Abandoned mine lands are common to human-altered landscapes. Despite the improvement of remediation techniques, the geomorphic and ecological function of historical abandoned mines persist as a concern to many regions. Cuyahoga Valley National Park (CVNP) is home to ~50 abandoned gravel, sand, and topsoil mines. After mining ceased, these sites were backfilled, compacted, and seeded. Following reclamation, rills and gullies appeared on some steep slopes within the sites. Additionally, reforestation efforts at these sites have not been successful. The causes of these failures are not well understood. Previous studies of coal mines have pointed toward altered chemical properties as a cause of reforestation failure. However, since the CVNP sites lack coal and associated tailings, further research is required to understand how the mining and reclamation affect erosion control and reforestation efforts.
Our research is investigating the geomorphology and soil quality of five of the abandoned mine sites within CVNP relative to four reference sites with similar slope and aspect, but mature forest. We aim to (1) determine the quality of the soils within the sites in comparison to the reference locations, (2) determine if the sites are currently undergoing erosion in exceedance of the reference locations, and (3) inform future reclamation projects to assist in the creation of successful practices.

We have collected ~250 soil samples from the five sites and four reference locations to analyze for grain size distribution, soil pH, concentrations of extractable Al, Ca, Fe, K, Mg, and P, and total C and N. Preliminary results indicate a marked difference in soil pH between the mined (pH 7-8) and forested reference (pH 3.6-6) sites. Measurements of infiltration capacity and bulk density are underway. Preliminary results of bulk density indicate that the density is very high (>2000 kg/m3) in the mined sites, which may be impeding plant growth and promoting overland water flow. Pressure transducers in three gullies on the mined sites indicate water flow during and following intense rainfall, and silt fences are allowing us to quantify sediment flux. Mapping of gully long profiles and cross-sections will enable us to calculate the volume of sediment removed by the gullies since reclamation occurred.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6
doi: 10.1130/abs/2017AM-303598

Grassy hill with trees in the background. Cloudy sky.

One of the sites that Caytie is studying, as it appeared in October 2016. The several acre site was host to invasive Phragmites reeds and a failed tree planting.

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.

Surface runoff from a closed landfill and the effects on wetland suspended sediment and water quality

Watershed Hydrology lab undergraduate Cody Unferdorfer will be representing the lab at this year’s Geological Society of America meeting in Denver in September. The work that he will be presenting will build on preliminary work that won the Kent State University Undergraduate Research Symposium Geology/Geography division in April, and Cody will have more and better data and analyses to show of at GSA.

Update: Cody will be giving a poster in the session on Undergraduate Research Projects in Hydrogeology on Sunday.

Surface runoff from a closed landfill and the effects on wetland suspended sediment and water quality

Cody Unferdorfer (1), Anne Jefferson (1), Lauren Kinsman-Costello (2), Hayley Buzulencia (1), Laura Sugano (1)
1. Department of Geology, Kent State University
2. Department of Biological Sciences, Kent State University

During rainstorms, many wetlands receive surface runoff carrying sediment and dissolved materials. Some of the sediment and solutes remain within the wetland, where they impact aquatic organisms and nutrient cycling. With time, excess sediment can fill in a water body and destroy the aquatic ecosystem, or excess nutrients can lead to eutrophication. Closed landfills have compacted surfaces that can generate large amounts of surface runoff, and the goal of this project is to examine the effects of a closed landfill’s runoff on a wetland.

The study site is a constructed wetland in Parma, Ohio. Water samples were collected during storms beginning in July 2015. We monitored five locations at the wetland: inflow from the landfill; inflow from two green infrastructure treatment trains; inflow from a stream seep, and outflow. Water samples were analyzed for suspended sediment concentration, water stable isotopes, and dissolved forms of nitrogen and phosphorus. Discharge was measured at the outflow.

Based on a preliminary analysis of four storms, of the inflows; the landfill contributes the most suspended sediment with an average of 400 mg/L. There is no correlation between TSS and discharge at the outflow. Instead a first flush effect was observed, where TSS concentrations decreased with time. The landfill inflow is close to the wetland outflow, which could allow for suspended sediment to bypass most interaction with the wetland’s interior. However, comparing rain and wetland outflow stable isotopes shows that water residence time often exceeds a single storm, suggesting that there are opportunities for biogeochemical processing of nutrient inputs within the wetland.

Runoff from the landfill (right) enters the wetland (left) near the wetland's outlet structure. What impact does this muddy water have on the wetland itself? Photo by a Watershed Hydrology lab member, August 7, 2015.

Runoff from the landfill (right) enters the wetland (left) near the wetland’s outlet structure. What impact does this muddy water have on the wetland itself? Photo by a Watershed Hydrology lab member, August 7, 2015.

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.

How low will they go? The response of headwater streams in the Oregon Cascades to the 2015 drought

From a distance, Anne has been watching an incredibly unusual summer play out in the Pacific Northwest, following a winter with far less snow (but more rain) than usual. Folks on the ground in Oregon have been collecting data on the response of the Oregon Cascades streams to “no snow, low flow” conditions. Anne is making minor contributions to the following poster, to be presented in Session No. 291, Geomorphology and Quaternary Geology (Posters) at Booth# 101 on Wednesday, 4 November 2015: 9:00 AM-6:30 PM.


LEWIS, Sarah L.1, GRANT, Gordon E.2, NOLIN, Anne W.1, HEMPEL, Laura A.1, JEFFERSON, Anne J.3 and SELKER, John S.4, (1)College of Earth Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, (2)Pacific Northwest Research Station, USDA Forest Service, 3200 SW Jefferson Way, Corvallis, OR 97331-8550, (3)Department of Geology, Kent State University, Kent, OH 44242, (4)Biological & Ecological Engineering, Oregon State University, Corvallis, OR 97331,

Larger rivers draining the Oregon Cascades are sourced from headwater systems with two distinct runoff regimes: surface-flow dominated watersheds with flashy hydrographs, rapid baseflow recession, and very low summer flows; and spring-fed systems, with slow-responding hydrographs, long baseflow recession, and summer flow sustained by deep groundwater fed coldwater springs. Our previous research has explored these differences on both the wet west-side and dry east-side of the Cascade crest, as expressed in contrasting discharge and temperature regimes, drainage efficiency, low and peak flow dynamics, and sensitivity to snowpack and climate change scenarios. In 2015, record low winter snowpack combined with an anomalously dry spring resulted in historically low flows across our research sites and throughout Oregon. These extreme meteorological conditions, equivalent to a 4°C warming scenario, offer an exceptional opportunity to witness how these contrasting stream networks might respond to anticipated changes in amount and timing of recharge.
Conceptually, channel network response to decreasing discharge may involve both lateral and longitudinal contraction. Lateral contraction, the decrease of wetted channel width and depth, occurs in both surface-flow and spring-fed streams as flows diminish. Longitudinal contraction may be expressed as (a) a gradual drying of the stream channel and downstream retreat of the channel head, (b) a “jump” of the channel head downstream to the next spring when an upper spring goes dry, or (c) no change in channel head despite diminishing flows. We hypothesize that while individual stream channels may display a combination of these dynamics, surface-flow and spring-fed watersheds will have distinctive and different behaviors. We field test our hypothesis by monitoring channel head locations in 6 watersheds during the low flow recession of 2015, and repeatedly measuring discharge, water quality and hydraulic geometry at a longitudinal array of sites along each surface-flow or spring-fed channel. The resulting data set can be used to explore the fundamental processes by which drainage networks accommodate decreasing flows.

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.