Currently browsing tag

GSA

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.

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

Abstract
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.

GSA 2013: Revisiting watershed drainage density: New considerations for hydrologic prediction

While I’ll be missing the festivities at the 125th anniversary edition of the the Geological Society of America, my able collaborator Sarah Lewis will be presenting our work in a session on “Quaternary Geology and Geomorphology: Past, Present, and Future.” Here’s what she’ll be showing off:

Revisiting watershed drainage density: New considerations for hydrologic prediction

S.L. Lewis, M. Safeeq, A.J. Jefferson, G.E. Grant

Watershed morphometry has long been identified as a major control on the shape and character of the hydrograph. Easily extractable landscape-level metrics have been explored for hydrologic prediction in ungaged watersheds, with varying success. In particular, mean drainage density (stream length/watershed area), which has a strong theoretical relationship to flow, has been both heralded and cast aside as an explanatory variable for hydrograph characteristics. However, previous approaches did not account for the spatial heterogeneity in drainage density within a single watershed. For example, many watersheds in the Oregon Cascades are comprised of both young lava flows with limited drainage networks, subtle peaks and sustained baseflows, and older highly dissected volcanics with steep slopes and flashy hydrographs. A mean drainage density fails to represent this dichotomy.

Here we revisit the long-standing conceptualization of drainage density as a good predictor of flow behavior at the landscape level. We depict drainage density (Dd) heterogeneity as a probability distribution function (pdf) of individual drainage densities within a watershed. Rather than limiting Dd to a single number (mean), we use standard quantitative descriptors of the pdf to explore landscape-level controls on flow regime. Two watersheds with similar mean values may have dramatically different pdfs and therefore exhibit variations in flow dynamics. We assert that some of the inconsistent results applying Dd as a predictive variable may be due to the accuracy with which a mean value can capture the behavior of a drainage network. In watersheds where drainage density is homogeneous, mean Dd may provide a good approximation of drainage behavior, but in watersheds where drainage density is heterogeneous, quantitative descriptors of the pdf can provide additional insight into flow dynamics.

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.