Kent Dam with canal lock and towpath behind it, in this undated photo from Kentohio.net.

For 168 years, a dam stood across the Cuyahoga River, under the main street bridge, and impounded water for a couple of miles upstream. In 2004, the dam was modified to let the river be free-flowing through town. The arched stone dam face was preserved but the remnants of a Pennsylvania and Ohio Canal lock structure were removed, creating a narrow chute in the river where once there was a full blockage. After the reservoir drained, some of the sediments were regraded to form a well-signed little heritage park behind the dam.

Looking upstream at the dam in August 2012. In the summer, water is recirculated to a trough at the top of the dam in order to give the illusion of a waterfall. On beautiful spring evenings, like this week, the park behind the dam is filled with people enjoying the weather…or studying.

Looking downstream through an arch of the Main Street bridge at the remaining section of the dam on the right and the former lock, now river on the left. Photo April 30, 2013.

Above the dam site, the river is confined to a fairly narrow bedrock gorge with class 2 rapids. In a few places you can easily get down to it and see some nicely potholed rock in the riverbed. Kayakers call this a pin spot.

Looking upstream from the pin spot on the Cuyahoga in Kent. Co-blogger and the High Albedo geo-dog for scale.

While we were wandering down there a few evenings ago, we met an angler who caught and released two small trout from the river in the space of about five minutes. There was no fish passage around the Kent Dam before it was removed, so I’m taking the trout as a good sign of some ecological recovery in this section of the river. Another good ecological sign has been spotted a few miles downstream. Rebuilding of another bridge over the river in Kent has been delayed so that endangered native mussel beds can be relocated.

Looking downstream from the pin spot between Main St and Crain Ave. Look closely for the angler near the river.

I know that the dam removal decision in 2004 was controversial in the community – generations had grown up with the dam as a local landmark and it was on the National Register of Historic Places – but when I walk along this section of the river, I am impressed not only by the wonderful ecology and geomorphology of this little river that runs through our downtown, but I’m also impressed by the community’s embrace of the free-flowing Cuyahoga. On this day, so important to Kent’s history, it gives me hope that we can overcome the wrongs and divisions of the past and work together to make a better future for both our communities and the world around us.

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.

Abstract:

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 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.

Meet Mr. Toilet | Jessica Yu from Focus Forward Films on Vimeo.

Lost Rivers is a new documentary by Montreal-based Catbird Films, and it tells the story of how cities built around water, then built over it “losing” the rivers, and how today we are starting to uncover those rivers again. The film was released earlier this year, and there’s only been two other screenings of it in the US so far. And totally unbeknownst to me, the third US screening is here in Kent, Ohio on Friday (April 19th) as part of the Who’s Your Mama? Environmental Film Festival. The film festival runs from 5 to 9 pm, with lots of great shorts, and Lost Rivers is the featured documentary, which will show at 7:30 pm. The film festival is in the Kiva on the Kent State Campus, and admission is $7, $5 for students and seniors, or free for kids under 12. There will also be local food tastings and booths by local environmental organizations, including Kent State’s student group CRICK.

Lost Rivers – OFFICIAL TRAILER from Catbird Productions on Vimeo.

Doesn’t it look great? I’ll definitely be at the screening on Friday, and I hope I’ll see some of my students there as well (though I know many will be on a field trip). In any case, I’ll report back, but I’m hopeful that by the next time I teach Urban Hydrology, I’ll have a copy on DVD and be able to show it to my class. Whee!

As the final stop of what has come to feel like a speaking tour this spring, I found myself condensing the stream restoration talk down to about 20 minutes. Here’s what the abstract said.

Jefferson, Anne J.*¹, Sandra Clinton², and Mackenzie Osypian². Evaluating the effects of restoration on transient storage and ecosystem services in urban headwater streams
1. Kent State University, Kent, OH.
?2. University of North Carolina at Charlotte, Charlotte, NC. ?

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 diversity. In Charlotte, North Carolina, we have evaluated restored and unrestored streams to quantify and compare transient storage. 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 had lower hydraulic conductivity of bed sediments, which was likely related to the construction of the restoration. The net effect of restoration was to greatly increase in-stream transient storage, while not appreciably increasing hyporheic exchange. Evaluating the ecological effects from changes in transient storage was complicated by the effects of canopy removal around stream restoration projects, the combination of which resulted in higher water temperatures and reduced benthic diversity. 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.