Currently browsing category

abstracts

AGU Abstract: Dynamic Hydraulic Conductivity, Streambed Sediment, and Biogeochemistry Following Stream Restoration

The Watershed Hydrology Lab will be represented at the AGU Fall Meeting in December in the session on “Groundwater-Surface Water Interactions: Identifying and Integrating Physical, Biological, and Chemical Processes.”

Dynamic Hydraulic Conductivity, Streambed Sediment, and Biogeochemistry Following Stream Restoration

Anne Jefferson, Stuart Baker, and Lauren Kinsman-Costello, Kent State University, Kent, OH, United States

Stream restoration projects strive to improve water quality and degraded habitat, yet restoration projects often fall short of achieving their goals. Hyporheic exchange facilitates biogeochemical interaction which can contribute to positive water quality and habitat, but there are limited data on how restoration affects hyporheic processes. Hyporheic flowpaths can be altered by the processes and products of stream restoration, as well as the transport of fine sediment through the stream bed post-restoration. In two northeastern Ohio headwater streams, variations in hydraulic conductivity and pore water chemistry were monitored following restoration, as measures of hyporheic functioning. A second-order stream restored in August 2013, had a slight decrease in average hydraulic conductivity but an increase in heterogeneity from pre-restoration to four months post-restoration. Data collected 10 and 15 months post-restoration show continued declines in hydraulic conductivity throughout large constructed riffles. These piezometers also indicate dominance of downwelling throughout the riffles with only isolated upwelling locations. Grain size analysis of freeze cores collected in streambed sediments show differences suggesting fluvial transport and sorting have occurred since construction was completed. Pore water sampled from piezometers within the riffles had Mn2+ concentrations ten times higher than surface water, suggesting redox transformations are occurring along hyporheic flowpaths. A first-order stream reach, immediately downstream of a dam, restored in April 2014 had no significant change in average hydraulic conductivity between 1 and 2 months post-restoration, but many individual piezometers had increases of over 100% in high gradient positions or decreases of over 50% in low gradient positions. Changes in hydraulic conductivities in both restored streams are thought to be an adjustments from disturbance to a new dynamic equilibrium influenced by the morphology and sediment regime established by restoration, suggesting these are important processes to consider in the design of such projects.

One of the study streams, 3 months post-restoration.

One of the study streams, 3 months post-restoration.

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

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

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

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

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

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

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

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

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.

After the dam comes down: groundwater-stream interactions and water quality effects of restored and unrestored reaches in northeastern Ohio

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

AFTER THE DAM COMES DOWN: GROUNDWATER-STREAM INTERACTIONS AND WATER QUALITY EFFECTS OF RESTORED AND UNRESTORED REACHES IN NORTHEASTERN OHIO

BROWN, Krista Marie, Geology, Kent State University, Kent, OH 44240, kbooth@kent.edu and JEFFERSON, Anne J., Department of Geology, Kent State University, 221 McGilvrey Hall, Kent, OH 44240

Over that past decade, dam removals have become increasingly popular, as many dams near the end of their life expectancy. With an anticipated increase of dam removals in coming years, this study aims to develop an understanding of groundwater-stream interactions and water quality in former reservoirs after dam removal. Low head dams were removed in 2009 on Plum Creek and Kelsey Creek, tributaries to the Cuyahoga River. Kelsey Creek reservoir remains unaltered and consists of a stream channel flowing through riparian-wetland environments, while Plum Creek reservoir underwent channel restoration in 2011. At Kelsey Creek, 20 piezometers and 3 wells were installed within the former reservoir. Since October 2013, hydraulic heads have been recorded semi-weekly for aquifer modeling and water samples have been taken in the wells and stream. Water quality is being evaluated with field-measured parameters and ion chromatography. Plum Creek is being used to understand the water quality effects of channel restoration.
At Kelsey Creek, interaction between the stream and shallow groundwater is evident. The stream tends to contribute shallow groundwater flow toward the western side of the site and north, parallel to the stream. The well closest to the stream shows variability in specific conductance, indicating bidirectional groundwater-stream exchange and all wells show rapid response to precipitation events. Hydraulic conductivity calculated using the Hvorslev method ranged 2.84×10-2to 7.38×10-6 m/s and poorly correlate with the bulk sediments in Kelsey Creek.
Despite the wetland and groundwater-stream exchange in the unrestored Kelsey Creek, there is little change in stream water quality within the former reservoir site, similar to the restored Plum Creek site. This suggests that there is little water quality benefit to be gained from stream restoration at dam removal sites. Left unaltered, Kelsey Creek provides flood control and groundwater recharge in wetland areas.

Sensitivity of precipitation isotope meteoric water lines and seasonal signals to sampling frequency and location

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.

SENSITIVITY OF PRECIPITATION ISOTOPE METEORIC WATER LINES AND SEASONAL SIGNALS TO SAMPLING FREQUENCY AND LOCATION

REYNOLDS, Allison R., Department of Geology, Kent State University, 221 McGilvrey Hall, Kent, OH 44242, areyno13@kent.edu and JEFFERSON, Anne J., Department of Geology, Kent State University, 221 McGilvrey Hall, Kent, OH 44240
Every precipitation event has its own isotopic signature, making it useful for hydrology purposes, like estimating transit time or identifying seasonality of groundwater recharge. Our purpose is to compare the seasonal signal and local meteoric water line (LMWL) generated by one year of event-based sampling to those resulting from multi-year monthly sampling at the closest Global Network of Isotopes in Precipitation (GNIP) stations. The question we seek to answer is whether data from different sampling strategies, periods, and locations within the eastern Great Lakes region in North America converge on a regional-scale LMWL and seasonal signal.
From October 2012-present precipitation samples were collected in Kent, Ohio, filtered and analyzed by a Picarro L-2130i at Kent State University. The closest GNIP sites are Coshocton, Ohio, USA and Simcoe, Ontario, Canada; monthly data was downloaded from a database. For each site, we graphed the ?18O versus ?2H and added a linear trendline to represent the LMWL and fit sine waves to the data to assess seasonal isotopic signal.
Based on the event data, Kent has the most isotopically depleted precipitation, but when looking at monthly samples, it falls between Simcoe to the north and Coshocton to the south. This suggests that, in this region, isotopically light precipitation events are more important in terms of their frequency than their amount. LMWLs for each site were similar. Comparing the LMWLs generated from the event samples and monthly data, monthly data had a slightly lower slope and d-excess. For Coshocton, amplitude of the seasonal sine wave for ?18O is 6.2‰, for Simcoe the sine wave is 4.3 ‰. For the Kent dataset, event-based data produced a sine wave with amplitude of 6.1‰, while monthly data resulted in a 4.9‰ amplitude wave. While it is possible that the amplitude of a wave fit to monthly data would increase with data points that represent isotopically extreme months, it is likely that curves fit to monthly data will frequently under-represent the variability in precipitation isotopes as measured at event and sub-event timescales. Both the LMWL and seasonal signal analysis suggest a greater variability in precipitation isotope signatures during the winter relative to the summer in the eastern Great Lakes region.

Changes in hyporheic exchange and subsurface processes following stream restoration

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.

CHANGES IN HYPORHEIC EXCHANGE AND SUBSURFACE PROCESSES FOLLOWING STREAM RESTORATION

BAKER, Stuart B., Department of Geology, Kent State University, 221 McGilvrey Hall, 325 S. Lincoln St, Kent, OH 44242, sbaker51@kent.edu and JEFFERSON, Anne J., Department of Geology, Kent State University, 221 McGilvrey Hall, Kent, OH 44240
Stream restoration is a billion dollar industry with major goals of improving water quality and degraded habitat, yet restoration often falls short of significant improvements in toward these objectives. At present, there are limited data and understanding of the physical and biogeochemical responses to restoration that constrain the potential for water quality and ecological improvements. Hyporheic exchange, the flow of water into and out of the streambed, is an important stream process that serves a critical role in naturally functioning streams, allowing for stream water to interact with the substrate in various processes. Hyporheic flowpaths can be altered by the transport of fine sediment through the stream bed and are thus susceptible to changes in sediment regime and hydraulics, as well as the changes wrought by construction of a restoration project. The goal of this research is to determine the effect of restoration on hyporheic exchange and associated biogeochemical processes. Preliminary results from Kelsey Creek, OH, a second-order stream restored in August 2013, show a slight decrease in average hydraulic conductivity but an increase in heterogeneity from pre-restoration (geometric mean 8.47×10-5 m/s, range 2.67×10-5-3.05×10-4) to four months post-restoration (geometric mean 4.40×10-5 m/s, range 1.18×10-6-1.19×10-3) to ten months post-restoration (geometric mean 1.41×10-5 m/s, range 1.11×10-6-6.40×10-4) in piezometer nests through large constructed riffle structures. These piezometers also indicate dominance of downwelling throughout riffle structures with only isolated locations of upwelling. A stream in Holden Arboretum, OH restored in April 2014 had no significant change in average hydraulic conductivity between 1 and 2 months post-restoration, but many individual piezometers had increases of over 100% or decreases of over 50%. The greater variation in hydraulic conductivities in both restored streams may be adjustment from disturbance to a new dynamic equilibrium. Transient storage and hyporheic exchange were also measured with resazurin injections pre-restoration and post-restoration, and nutrient injections of NH4Cl will compare the nitrogen uptake rates of the restored reach to an unrestored reach downstream.

The effects of biogeochemical sinks on the mobility of trace metals in an area affected by acid mine drainage, Huff Run, 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.

THE EFFECTS OF BIOGEOCHEMICAL SINKS ON THE MOBILITY OF TRACE METALS IN AN AREA AFFECTED BY ACID MINE DRAINAGE, HUFF RUN, OHIO

TRAUB, Eric L., Department of Geology, Kent State University, 325 S. Lincoln St, 221 McGilvrey Hall, Kent, OH 44240, etraub@kent.edu, JEFFERSON, Anne J., Department of Geology, Kent State University, 221 McGilvrey Hall, Kent, OH 44240, and SINGER, David M., Department of Geology, Kent State University, 228 McGilvrey Hall, Kent, OH 44242
Currently, a watershed restoration group has made progress in remediating surface water contributions to the Huff Run Stream in Mineral City, OH, which is heavily affected by acid mine drainage (AMD) due to historical coal mining. However, the accumulation of AMD sediments on the streambed has prevented the overall ecological health of the area from rebounding. A proposed remediation plan includes dredging, however the efficacy of doing so while preventing further iron buildup and the potential release of trace metals during such an operation is uncertain. The objectives of this research are to examine the effects geochemical sinks can have on the fate and transport of trace metals in order to understand the possible side effects of dredging on the Huff Run. This work aims to build a framework on which to base proposed remediation plans at a wide range of acid-mine drainage impacted sites. To achieve these objectives cores were gathered from the Huff Run and the Farr tributary, where a large amount of AMD is discharged into the Huff Run. These core sediments were analyzed through XRD analysis to understand the abundance and distribution of mineral phases, and ICP analysis to provide information on the amount of trace metals and understand what mineral phases they are associated with. Groundwater piezometers installed in AMD-bearing sediments and streambed sediment were used to quantify changes in trace metals concentrations. The analyses of cores gathered from the stream provide evidence that overtime deposited iron oxides go through thermodynamic transformations into more stable phases, mainly goethite. On-going work aims to determine how mineralogical transformations impact the availability of trace metals. Hydraulic head values gathered the piezometers have shown that hyporheic exchange is occurring, despite the deposition of fine grained sediment and iron oxides from historical mining. Water samples collected from the piezometers have been analyzed for pH and conductivity and show consistent changes as the water is exchanged from the surface and groundwater. On-going work aims to determine how this exchange affects the transport of trace metals.

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.

Rayleigh isotope distillation module – development and transferability in geoscience education

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.

RAYLEIGH ISOTOPE DISTILLATION MODULE – DEVELOPMENT AND TRANSFERABILITY IN GEOSCIENCE EDUCATION

GRIFFITH, Elizabeth M., Earth and Environmental Sciences, University of Texas at Arlington, 500 Yates St, Arlington, TX TX 76019, lgriff@uta.edu, ORTIZ, Joseph D., Department of Geology, Kent State University, 221 McGilvrey Hall, Kent, OH 44242, JEFFERSON, Anne J., Department of Geology, Kent State University, 221 McGilvrey Hall, Kent, OH 44240, DEES, David, Faculty Professional Development Center and School of Foundations, Leadership and Administration, Kent State University, 231 Moulton Hall, Kent, OH 44242, and MERCHANT, William, Department of Evaluation and Measurement, Kent State University, 111L Nixon Hall, Kent, OH 44242
Rayleigh distillation is an important concept in geochemistry – applied to isotopic and elemental systems ranging from crystallization in magma chambers to oxygen isotope stratigraphy across glacial-interglacial periods. A teaching module that allows students to discover first-hand consequences of isotopic fractionation and Rayleigh distillation was developed, peer-reviewed, modified and used in thre upper-division geoscience courses: Sedimentology/Stratrigraphy, Environmental Geochemistry and Paleoceanography. In the module “Rayleigh isotope effect in the oceans: building glaciers” students perform (or are given data from) a simple batch distillation experiment that they model using open system Rayleigh isotopic fractionation. Insight on isotopic fractionation during phase transitions and a fundamental understanding of oxygen isotope stratigraphy is learned first-hand by the students preforming simple experiments and analyzing the data on sophisticated equipment. The teaching module is adaptable for the geoscience curriculum, including upper division courses and introductory courses. The module has only been tested in three upper division courses, but future work adapting and implementing the activity in an Introduction to Oceanography lab is planned.
Funding by the NSF Division of Undergraduate Education allowed us to study the impact on student learning and motivation from teaching the material within the module using different pedagogical approaches including a paper-based data analysis activity and hands-on data collection with and without access to the water isotope analyzer. Assessment techniques were developed and implemented through the close collaboration with a faculty expert within the educational field. The 3-year project is in its second year and initial quantitative results and reflections from the faculty and students will be presented. Both faculty noted a difference in the classroom dynamic with the students performing the experiments vs those completing the paper-based data analysis. Additional strategies will be highlighted for the transferability of the hands-on experiment to institutions and departments without access to the water isotope analyzer.