The Secret Life of Rivers from S Solomon Leaping Frog Films on Vimeo.
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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.
HOW LOW WILL THEY GO? THE RESPONSE OF HEADWATER STREAMS IN THE OREGON CASCADES TO THE 2015 DROUGHT
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, firstname.lastname@example.org
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.
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.
As California’s drought continues and intensifies, groundwater is ever more heavily exploited. Groundwater withdrawals are happening much faster than natural recharge will ever occur, and the consequences can literally move the ground beneath your feet. This video from the USGS is a nice explainer:
For more on California’s climate and water woes, check out my review of the book “The West Without Water,” which was published last spring in Earth Magazine.
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, email@example.com 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.
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…
After the dam comes out: groundwater-stream interactions and water quality impacts of former reservoir sites
Krista Brown and Anne Jefferson
Over that past decade, dam removals have become increasingly popular, as many dams near the end of their life expectancy. With an increasing number of anticipated dam removals coming in the near future this study aims to develop an understanding of groundwater-stream interactions and water quality in former reservoir sites after dam removals have occurred. Low head dams (~2 m) were removed in 2009 from Plum Creek in Kent, Portage County, Ohio and on Kelsey Creek in Cuyahoga Falls, Summit County, Ohio. Kelsey Creek reservoir has been unaltered since the dam removal 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 in the stream and riparian areas. Pressure transducers were also deployed in each well and stream from November 20, 2013 to January 5, 2014. Hydraulic conductivity was calculated using the Hvorslev method. Since October 2013, hydraulic heads have been recorded semi-weekly and water samples have been taken in the wells and stream. Water quality is being evaluated with field-measured pH, temperature, specific conductance, and dissolved oxygen, and ion chromatography of chloride, bromide, nitrate, sulfate and phosphate concentrations. Plum Creek is being used to understand the water quality effects of channel restoration at former reservoir sites.
At Kelsey Creek, hydraulic conductivity ranges five magnitudes, from 10?2 to 10?6 m/s, but wells near the channel, in an off-channel wetland, and on an adjacent hillslope respond similarly during high flow events. However, the well closest to the stream shows substantial variability in specific conductance, indicating bidirectional groundwater-stream exchange. Despite the wetlands and presumed greater groundwater-stream exchange in the unrestored Kelsey Creek, stream water quality is similar to the restored Plum Creek site. This suggests that the water quality measures considered here should not determine whether to restore channels within former reservoir sites. Findings from this research may be applicable when considering options for future dam removal sites.
Kent State University Department of Geology’s Watershed Hydrology class visited the Susquehanna Shale Hills Critical Zone Observatory on April 5-6, 2014. Penn State post-doc Pamela Sullivan gave them a tour of the watershed and its instrumentation, with a focus on how the measurements could contribute to understanding how hydrology drives landscape evolution on shales. The students were introduced to the challenges of hydrologic field work as they attempted to produce a continuous flow of water from a 75′ foot deep well on the watershed’s ridgeline. On Sunday, the students learned and practice water quality sampling protocols and collected water samples from streams and shallow wells in the CZO watershed and in watersheds with differing geology.Temperature, pH, specific conductance, and DO were measured in the field, and ions, cations, and stable isotopes will be measured in laboratories at Penn State and Kent State. The students will discuss these data in class over the next several weeks as they integrate their understanding of how geology and topography control hydrologic flowpaths, streamflow generation mechanisms, and water quality.
The class stayed on the shores of Lake Perez, which has been drained for the last few years to enable repairs on the dam. The lake has just begun refilling, but while empty it has created some interesting research opportunities.
I’ll try to add some more beauty shots of the CZO watershed at some point, but I wanted to be able to show our class in action in the field.
Congratulations to Darren Reilly who did a wonderful job defending his MS thesis on Tuesday. Darren’s thesis focused on the identification of groundwater pollution and its sources in rural northeastern Pennsylvania residential water wells. Darren will be preparing his thesis for publication in a journal and is looking for a job in the energy or environmental sectors. Check him out on LinkedIn.
Congratulations also to Alison Reynolds who won first place in the Kent State Undergraduate Research Symposium, Geology/Geography category for her poster on “Sensitivity of precipitation isotope meteoric water lines and seasonal signals to sampling frequency and location.” Aly is a junior this year, and will be continuing to be a valuable member of our research group this summer and next year before heading somewhere fabulous for graduate school.
Congrats Darren and Aly. It is a pleasure to work with such passionate and dedicated students.
Department of Geology – MS Thesis Defense
“IDENTIFICATION OF LOCAL GROUND WATER POLLUTION IN NORTHEASTERN PENNSYLVANIA: MARCELLUS FLOW-BACK OR NOT?”
Tuesday, April 1, 9:15 am, McGilvrey 236
Co-advised by Drs. Anne Jefferson and David Singer
Abstract season is upon us. I’ll be at AGU, where there looks to be loads of good sessions, including one on “Groundwater-Surface Water Interactions: Physical, biological, and chemical relevance“. Hopefully, my work (abstracted below) will be part of this session.
Transient Storage versus Hyporheic Exchange in Low-gradient Headwater Streams
A.J. Jefferson, S.M. Clinton, M. Osypian
In-channel storage and hyporheic exchange are components of transient storage that exist as a function of geomorphology and which can have contrasting effects on nutrient retention, temperature, and biological communities. In order to evaluate and predict the effects of geomorphic changes on the biogeochemical and ecological functioning of transient storage zones, in-channel storage needs to be quantified separately from hyporheic exchange. In four headwater streams, we used salt injections modeled in OTIS-P to quantify total transient storage fluxes and piezometer measurements to quantify hyporheic fluxes. In the mixed bedrock-alluvial streams, restoration increased both in-channel and hyporheic exchange fluxes, but in-channel transient storage was dominant. In the fully alluvial streams, total transient storage fluxes were ~100 times greater in the stream which had undergone restoration than in one where no restoration had occurred. Conversely, hyporheic fluxes were ~400 times smaller in the restored alluvial stream. Thus, in the restored stream, hyporheic flux was <1% of total transient storage flux, while in the unrestored stream, hyporheic flux accounted for up to 75% of total transient storage fluxes. This difference in the contribution of the hyporheic zone to total transient storage appears to be a function of both channel morphology and bed sediments, primarily the creation of pools and reduction in sediment size that occurred as a result of restoration. These dramatic variations in the magnitude and relative proportions of in-channel and hyporheic fluxes that occur across low-gradient, headwater streams may be an important control on reach-scale biogeochemical and ecosystem functioning.