NU Water-Related Research in Thomas County

The list below shows water-related research being conducted within your district or that affects your district. They are sorted by water topic, then by primary contact's last name.

Displaying 13 records found for Thomas County


Topic Climate
Project's Primary Contact Information
Name Shulski, Martha
Unit High Plains Regional Climate Center
Email mshulski3@unl.edu
Phone 402-472-6711
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=474
Project Information
Title High Plains Regional Climate Center - Monitoring Stations
Description

As the demand for water grows, it is important to have reliable information for various assessments, such as drought, fire, and water development. In an effort to understand the surface hydrology and the water and energy interactions at the surface, scientists with the High Plains Regional Climate Center have installed a series of monitoring stations that collect temperature, humidity, solar radiation, windspeed and direction, soil temperature, precipitation and soil moisture data. These stations take hourly and daily data which can be used to calculate evapotranspiration and water balance terms. Monitoring equipment is located near Higgins Ranch, Sparks, Merritt, Ainsworth, New Port, Barta, Gudmundsens, Halsey, and Merna.

Volunteers supplement these stations by using rain gauges to monitor precipitation; volunteers enter their data online as part of the Nebraska Rainfall Assessment and Information Network (NeRAIN). In total volunteers from 40 states contribute precipitation data to the Community Collaborative Rain, Hail and Snow Network (CoCoRaHS). The CoCoRaHS network has been incorporated into the Applied Climate Information System (ACIS), which allows resource managers, researchers, and decision-makers to better access data.

Project Support National Climatic Data Center
Project Website http://hprcc.unl.edu
Report
Current Status Continuing
Topic Hydrology
Project's Primary Contact Information
Name Lenters, John
Unit School of Natural Resources
Email jlenters2@unl.edu
Phone 402-472-9044
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=743
Project Information
Title On Basin Residence Time and Annual Hydrology: Development of Annual Hydrology Model of the Sandhills Rivers
Other(s) Erkan Istanbulluoglu, University of Washington, erkani@u.washington.edu; Durelle Scott, Virginia Tech, dscott@vt.edu; Tiejun Wang, University of Washington-Seattle, tjwang@u.washington.edu 
Description

Simple models of annual and mean annual basin runoff and evapotranspration, such as the one proposed by Budyko, are useful for investigating the relationship between river flow and climate, and planning water storage structures in basins where long term streamflow measurements are not available. Such models are often based on the assumption that annual precipitation is in balance with annual runoff and evapotranspiration, and change in water storage of the basin is negligible. In basins where groundwater is the dominant source of streamflow this assumption hardly holds.

In this study first we develop a technique to investigate groundwater residence time to identify time scales over which a simple model of mean annual runoff can be meaningfully used. The model is applied in the Niobrara and Loup Rivers. Second we develop an annual hydrology model by solving the rate of change in basin storage. The runoff component of the model is based on the well-known linear reservoir model and a parameterization to characterize runoff on saturated areas. River water storages and streamflow diverted for irrigation are included as inputs in the model. The model explained as high as 80% of the annual variability of runoff in the Niobrara River at the Sparks gage. The model underscores the importance of saturation overland flow in the basin. Finally we used the model to investigate climate change scenarios, including extreme dry and wet conditions, as well as scenarios for the Medieval Warm Period during which Sandhills were destabilized as suggested by geological evidence.

Project presentation at the 2008 Water Colloquium

Project Support National Science Foundation
Project Website
Report Lenters_Groundwater.pdf
Current Status Published "On the role of groundwater and soil texture in the regional water balance: An investigation of the Nebraska Sand Hills", USA, Water Resour. Res., 45, W10413, doi:10.1029/2009WR007733.
Topic Hydrology
Project's Primary Contact Information
Name Pederson, Darryll
Unit Earth and Atmospheric Sciences
Email dpederson2@unl.edu
Phone 402-472-7563
Web Page http://eas.unl.edu/people/faculty_page.php?lastname=Pederson&firstname=Darryll&type=REG
Project Information
Title Waterfalls on the Niobrara River's Spring-fed Tributaries
Description The waterfalls on the spring-fed tributaries of the Niobrara River downstream from Valentine, Nebraska are unique in that the waterfalls are convex downstream. Groundwater discharge on either side of the waterfalls has led to significant weathering because of freeze/thaw cycles in the winter and wet/dry cycles in the summer. The water falling over the face of the falls protects them from the two weathering processes. Because the weathering rates on either side are higher than the erosion rates from falling water, the face of the falls is convex downstream. Similar waterfall face morphology occurs on the Island of Kauai where the main weathering processes are driven by vegetation and the presence of water.
Project Support National Park Service through the Great Plains Cooperative Ecosystem Studies Unit
Project Website http://snr.unl.edu/gpcesu/Project_library.htm
Report Waterfalls_Abstract.pdf
Current Status Completed
Topic Hydrology
Project's Primary Contact Information
Name Wang, Tiejun
Unit School of Natural Resources
Email tiejunwang215@yahoo.com
Phone
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=945
Project Information
Title Niobrara River Flow Variability
Other(s) Erkan Istanbulluoglu, University of Washington, erkani@u.washington.edu 
Description This project develops a database for hydrological and climatological variables within the Niobrara River basin so that researchers may study flow variability in the Niobrara River and its historical changes. Analysis includes all existing and discontinued streamflow gages within the system. Surface water diversion data are also collected to relate to changes in the flow discharge. Annual water yield of the river is studied at Sparks and Verdel gages. A lumped annual water yield model is developed to identify the natural variables that control runoff. The model uses annual runoff as forcing variable, as well as water diversions as outflux from the system. The model is currently being extended to monthly time scales.
Project Support Nebraska Game and Parks Commission, National Park Service
Project Website
Report
Current Status Underway
Topic Sandhills Studies and Modeling
Project's Primary Contact Information
Name Awada, Tala
Unit School of Natural Resources
Email tawada2@unl.edu
Phone 402-472-8483
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=4
Project Information
Title Soil Moisture Use by Grasses and Trees in the Sandhills
Other(s) Kathleen Eggemeyer, Texas State University, keggemeyer@txstate.edu; Ed Harvey, School of Natural Resources, feharvey1@unl.edu; David Wedin, School of Natural Resources, dwedin1@unl.edu; Xinhua Zhou, School of Natural Resources, xzhou2@unl.edu; C. William Zanner, University of Minnesota, bzanner@umn.edu 
Description

The Sandhills are well known as Nebraska's grassland region. The continued presence of relatively shallow-rooted grasses in the Sandhills have contributed to making this region a major recharge zone for the High Plains Aquifer. Unfortunately, trees are encroaching on the Sandhills, potentially threatening the region's recharge capacity.

This study was conducted in the Nebraska National Forest at Halsey (located in Blaine and Thomas counties). Researchers established a network of soil moisture monitoring sites to observe how relatively shallow-rooted grasses (i.e., little bluestem and switchgrass) and deep-rooted trees (i.e., ponderosa pine and eastern red cedar) deplete soil moisture at depths up to 10 feet. The study confirmed that both grasses use mostly shallow soil water. Deeper switchgrass roots may serve as an important survival mechanism for the plant during drought, but overall switchgrass's deep roots contribute only a small fraction to the plant's total water uptake.

On the other hand, the study showed that both trees "exhibited significant plasticity in sources of water uptake." During winter both trees drew soil water from below 0.9 m depth and in spring from the upper soil profile (0.05 - 0.5 m). During the growing season (May-August), the pine drew water mostly from the upper and mid soil profiles (0.05 - 0.5 and 0.5-0.9 m). The cedar gradually moved from the upper to the mid soil profile, thus being less responsive to precipitation but taking advantage of available soil moisture.

Overall the study showed that ponderosa pines and eastern red cedars have been able to encroach into the Sandhills because the trees "acquired water outside of the growing season, competed for shallow water with grasses during spring and early summer, and depended on water drawn from deeper in the soil profile during drought."

For more information about this topic, see David Wedin's presentation, "Was Weaver Wrong? Rooting Depths and Soil Moisture Depletion in the Nebraska Sandhills".

Project Support McIntire Stennis Forest Research Funds - USDA, Interdisciplinary Research Grant, ARD-University of Nebraska-Lincoln, Center for Great Plains Studies, UNL Water Sciences Lab, US Forest Service
Project Website
Report Awada_Sandhills.pdf
Current Status Published in Tree Physiology 29:157-169
Topic Sandhills Studies and Modeling
Project's Primary Contact Information
Name Billesbach, Dave
Unit Biological Systems Engineering
Email dbillesbach1@unl.edu
Phone 402-472-7961
Web Page http://bse.unl.edu/faculty/Billesbach.shtml
Project Information
Title Effects of Precipitation and Groundwater on Grassland Productivity in the Nebraska Sand Hills
Other(s) Tim Arkebauer, Agronomy and Horticulture, tarkebauer1@unl.edu 
Description

In the Sand Hills the depth to groundwater greatly affects the types and amounts of grasses that grow there, suggesting a strong linkage between groundwater, precipitation, and grass productivity. Wet meadows are where the water rable is usually less than a meter below the surface and make up about 10% of the Sand Hills land area. Dry valleys are where the water table never intersects the land surface and usually lies several meters below; dry valleys also make up about 10% of the Sand Hills land area. Except for lakes and wetlands (about 2% of the land area), the rest of the Sand Hills is dunal uplands where the water table is many meters below the surface.

It has long been assumed that the Sand Hills are a recharge zone for the underlying aquifer and that local precipitation more than accounts for the water usage of surface vegetation. This research measures how much water enters the Sand Hills ecosystem (via precipitation) and how much water leaves the land surface - the Sand Hills surface water balance. Research shows that Sand Hills surface water is lost primarily through evapotranspiration, or surface water evaporation and plant transpiration, with the relative size of each varying greatly depending on the time of year and other factors, such as drought. Research also shows that: 1) the most water is transferred to the atmosphere from wet meadows, followed by dry valleys and dunal uplands; 2) the close proximity to the aquifer acts as a buffer to both wet meadows and dry valleys, but not to dunal uplands; and 3) groundwater buffering is most affected by regional rather than local precipitation events. The long-term goal of this project is to study and better understand the relationship between water and the vegetative land cover (carbon).

Project Support n/a
Project Website
Report Billesbach_SandHills_Water.pdf
Current Status Continuing
Topic Sandhills Studies and Modeling
Project's Primary Contact Information
Name Efting, Aris
Unit School of Natural Resources
Email aefting@unl.edu
Phone 402-472-3471
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=226
Project Information
Title Determining Toxic Algal Bloom Frequency in Nebraska Lakes
Description Research has been conducted in the Sandhills to determine whether or not there has been an increase in toxic algal blooms. Four different lakes were cored to identify the lakes' history of toxic algal blooms and determine whether there is an increase in toxin concentrations post 1950.
Project Support Layman Fund
Project Website
Report
Current Status Underway
Topic Sandhills Studies and Modeling
Project's Primary Contact Information
Name Hu, Qi (Steve)
Unit School of Natural Resources
Email qhu2@unl.edu
Phone 402-472-6642
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=54
Project Information
Title The Missing Term in Surface Water Balance in the Great Plains
Other(s) Jinsheng You, School of Natural Resources, jyou2@unl.edu 
Description

It has been recognized that the surface water budget derived from the NCEP-NCAR Reanalysis and other existing climatic datasets is not in balance in the Great Plains region. This imbalance is shown by large surface evaporation which cannot be supported by source terms in the budget equation. This large surface evaporation is always appearing in calculations from the surface and soil moisture conditions specified in those datasets. This imbalance poses serious uncertainties to diagnostic and modeling studies of energy and carbon balances and to our understanding of atmospheric/climatic processes in this region. An effort aiming at identifying sources causing the water budget imbalance has been underway and some preliminary results have been obtained. A main source of the imbalance arises from the calculation of the surface evaporation. It was found that the surface and soil water specified in those datasets (developed from integrations of both observations and model simulations) is biased because of inaccurate descriptions of the soil properties, particularly the sandy soils in the Nebraska Sand Hills. A revised model with more accurate descriptions of the soils and soil hydrology in the Sand Hills has produced a balance surface water budget in the Sand Hills.

Project presentation at the 2008 Water Colloquium

Project Support Department of Commerce - National Oceanic and Atmospheric Administration (NOAA)
Project Website
Report
Current Status
Topic Sandhills Studies and Modeling
Project's Primary Contact Information
Name Hubbard, Kenneth
Unit High Plains Regional Climate Center
Email khubbard1@unl.edu
Phone 402-472-8294
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=55
Project Information
Title Assessment of Soil Moisture Dynamics of the Nebraska Sandhills Using Long-Term Measurements and a Hydrology Model
Other(s) Venkataramana Sridhar; David Wedin, School of Natural Resources, dwedin1@unl.edu 
Description Soil moisture, evapotranspiration, and other major water balance components were investigated for six Nebraska Sandhills locations during a 6 year period (1998-2004) using a hydrological model. Annual precipitation in the study period ranged from 330 to 580 mm. Soil moisture was measured continuously at 10, 25, 50, and 100 cm depth at each site. Model estimates of surface (0-30 cm), subsurface (30-91 cm), and root zone (0-122 cm) soil moisture were generally well correlated with observed soil moisture. The correlations were poorest for the surface layer, where soil moisture values fluctuated sharply, and best for the root zone as a whole. Modeled annual estimates of evapotranspiration and drainage beneath the rooting zone showed large differences between sites and between years. Despite the Sandhills' relatively homogeneous vegetation and soils, the high spatiotemporal variability of major water balance components suggest an active interaction among various hydrological processes in response to precipitation in this semiarid region.
Project Support National Science Foundation, High Plains Regional Climate Center
Project Website
Report Hubbard06.pdf
Current Status Published in Journal of Irrigation and Drainage Engineering, September/October 2006, 463-473
Topic Sandhills Studies and Modeling
Project's Primary Contact Information
Name Loope, David
Unit Earth and Atmospheric Sciences
Email dloope1@unl.edu
Phone 402-472-2647
Web Page http://eas.unl.edu/people/faculty_page.php?lastname=Loope&firstname=David&type=REG
Project Information
Title Large Wind Shift on the Great Plains During the Medieval Warm Period
Other(s) Venkataramana Sridhar; James Swinehart, School of Natural Resources, jswinehart1@unl.edu; Joseph Mason, University of Wisconsin, Madison, mason@geography.wisc.edu; Robert Oglesby, School of Natural Resources, roglesby2@unl.edu; Clinton Rowe, Geosciences, crowe1@unl.edu 
Description Spring-Summer winds from the south move moist air from the Gulf of Mexico to the Great Plains. Growing season rainfall sustains prairie grasses that keep large dunes in the Nebraska Sandhills immobile. Longitudinal dunes built during the Medieval Warm Period (800-100 yBP) record the last major period of sand mobility. These dunes are oriented NW-SE and are composed of cross-strata with bi-polar dip directions. The trend and structure of these dunes directly record a prolonged drought that was initiated and sustained by a historically unprecedented shift of Spring-Summer atmospheric circulation over the Plains: southerly flow of moist air was replaced by dry southwesterly flow.
Project Support National Science Foundation
Project Website
Report Loope Wind Shift.pdf
Current Status Published in Science November 2007 318:1284-1286
Topic Sandhills Studies and Modeling
Project's Primary Contact Information
Name Wedin, Dave
Unit School of Natural Resources
Email dwedin1@unl.edu
Phone 402-472-9608
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=128
Project Information
Title Sand Hills Biocomplexity Project
Other(s) Vitaly Zlotnik, Department of Geosciences, vzlotnik1@unl.edu. 
Description

The Sand Hills, the largest sand dune area in the Western Hemisphere, is now stabalized by native grasses. This was not always the case. The Sand Hills have mobilized several times over the last 10,550 years. Major droughts destabilized significant portions of the Sand Hills as recently as 1000 years ago. The stability of the Sand Hills affects not only hundreds of cattle ranches, but also the recharge of the High Plains Aquifer. Of the total groundwater stored in this vast aquifer, 65% occurs in Nebraska and over half of that lies under the Sand Hills. The groundwater connection is obvious throughout the region. Due to the high water table, interdunal valleys in portions of the Sand Hills contain extensive complexes of lakes, wetlands, and naturally sub-irrigated wet meadows, which together cover over 10% of the landscape.

The Sand Hills Biocomplexity Project is a major federal project led by Professor Wedin. The project is aimed at testing whether:

  1. Evapotranspiration (ET) from wet valleys buffers the impacts of short-term drought on upland grasslands through local climate feedbacks. (resistance stability)
  2. When wetlands go dry, the combined effect of lost upland grass cover and lost wetland ET creates a desertification feedback that amplifies drought impacts.
  3. Since subregions of the Sand Hills differ in their extent of interdunal wetlands, subregions respond differently to paleo and historic droughts, thus enabling landowners to prepare for future droughts.
  4. Increased groundwater recharge when dunes are bare hastens the rise of groundwater levels, which, together with the rapid recovery of warm season grasses, restabilizes the dunes. (resilience stability)

The project's Grassland Destabilization Experiment (GDEX) is studying what happens to a Sand Hills dune when the vegetation dies. Researchers have created 10 circular plots at the Barta Brothers Ranch, each 120 meters in diameter, and used herbicide to kill all the vegetation on several of them. The plots are kept clear of vegetation, so that information on vegetation coverage, root mass, soil organic matter, and sand movement may be monitored and recorded to determine the stability of the plots. Results indicate that the Sand Hills may be more stable than previously thought; that is, ersosion is just starting to occur were vegetation was killed two years ago. Additional studies are needed to determine what happens when sand dunes become mobile.

As a part of this project, Professor Vitaly Zlotnik carries out research on groundwater recharge, hydraulic properties of the dune cover, and the climate change effects on groundwater recharge.

Project Support National Science Foundation
Project Website http://sandhills-biocomplexity.unl.edu/
Report
Current Status n/a
Topic Wildlife
Project's Primary Contact Information
Name Pegg, Mark
Unit School of Natural Resources
Email mpegg2@unl.edu
Phone 402-472-6824
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=739
Project Information
Title Habitat Usage of Missouri River Paddlefish Project
Description Sediment from the Niobrara River has created a delta area near the headwaters of Lewis and Clark Lake, the reservoir formed by Gavins Point Dam on the Missouri River. This sediment aggregation has reduced reservoir volume and threatens to fill the reservoir; therefore, restoration of reservoir capacity has been proposed by means of high-velocity water releases from upstream mainstem dams. Biologists, however, have reported that this delta area may serve as spawning grounds for native fishes like paddlefish, and may provide suitable spawning habitat for federally endangered pallid sturgeon. This situation has created a unique paradox where information is needed to provide insight into fulfilling both the river management needs and biological needs in the Missouri River. This project will use paddlefish telemetry to study spawning success.

Click here to read Brenda Pracheil's dissertation on Paddlefish populations

Project Support Nebraska Environmental Trust
Project Website
Report Pracheil et al_Fisheries_2012.pdf
Current Status Completed
Topic Wildlife
Project's Primary Contact Information
Name Young, Chelsey
Unit Biology, UNK
Email youngca2@unk.edu
Phone 507-469-8284
Web Page
Project Information
Title A range-wide assessment of plains topminnow (Fundulus sciadicus) distribution and potential threats
Other(s) W. Wyatt Hoback, Biology UNK, hobackww@unk.edu; Keith Koupal, Biology UNK; Justin Haas 
Description The plains topminnow, Fundulus sciadicus, was once distributed from the Mississippi River to the Rocky Mountains, north to South Dakota and as far south as Oklahoma. Two centers of distribution are recognized. One is centered in Nebraska and the second is centered in Missouri. The geographic range of plains topminnow has decreased in the past decades. Plains topminnow are now considered a species of special concern in the state of Nebraska and listed as a Tier 1 species in the Nebraska Natural Legacy Project. Elimination of plains topminnow populations has been associated with introduction of invasive species, as well as loss of backwater habitats due to drought and lowered water tables. The objective of this project is to provide an updated assessment of plains topminnow distribution and population status as compared to all available historical records. Between 2004 and the present, sampling of plains topminnow revealed that in Nebraska 77% of historic Nebraska sites no longer contain plains topminnow populations. The sampling of remaining historic sites in Nebraska and neighboring states will continue in the 2009 sampling season.
Project Support n/a
Project Website
Report topminnow_range_reduction.pdf
Current Status Completed