NU Water-Related Research in Polk 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 24 records found for Polk County


Topic Climate
Project's Primary Contact Information
Name Irmak, Suat
Unit Biological Systems Engineering
Email sirmak2@unl.edu
Phone 402-472-4865
Web Page http://bse.unl.edu/sirmak2
Project Information
Title Dynamics of Climate Change in Central Platte Valley, Nebraska, as Indicated by Agro-meteorological Indices over 116 years (1893-2008): Preliminary Analyses
Other(s) Kabenge, Isa Mutiibwa, Denis 
Description

It has been established with a degree of confidence that the temperature of the earth’s atmosphere has increased by about 0.3 to 0.6 degrees C in the late 19th century (IPCC, 1997). Global warming can have substantial impact on agricultural production, water resources, and their interactions, by influencing microclimatic variables that drive plant physiological functions, such as surface air temperature, solar radiation, humidity, wind speed, rainfall frequency and amount, as well as hydrological balances, including evapotranspiration. Knowledge and analyses of long-term historical trends in agro-meteorological and hydrological parameters can aid in water resources design, planning, and man-agement. Historical trends in these variables can also help to relate agro-ecosystem production to climate change. We assessed the long-term trends in climatic variables. We quantified reference evapo-transpiration from solar and net radiation, vapor pressure deficit, wind speed, relative humidity, and air temperature from 1893 to 2008 using measured and estimated climatic data. Both alfalfa-reference and grass-reference evapotranspiration values were computed on a daily time step. We present historical trends in air temperature, relative humidity, preci-pitation, solar radiation, and evapotranspiration from 116 years of climatic observations and modeling results in the Central Platte Valley, Nebraska.

Conclusions from this project are:

  • Missing long-term climatic variables from 1893 to 1986 were reliably estimated for reference ET calculations.
  • Annual total rainfall amount showed an increasing trend over 116 years.
  • Both grass and alfalfa-reference ET fluctuated from year to year, but slightly decreased over the years.
  • Solar radiation slightly decreased due to increased rainfall/cloud cover.
  • Average vapour pressure deficit (VPD) did not change considerably.
  • Aridity index trend indicates a general tendency for Central City, NE area to shift toward more humid conditions, more so in the last 10 years.
Project Support
Project Website
Report
Current Status Completed
Topic Crop Water Use
Project's Primary Contact Information
Name Irmak, Suat
Unit Biological Systems Engineering
Email sirmak2@unl.edu
Phone 402-472-4865
Web Page http://bse.unl.edu/sirmak2
Project Information
Title Mapping Spatial Distribution of Evapotranspiration and Other Energy Fluxes for Key Vegetation Surfaces
Other(s) Ayse Irmak, School of Natural Resources, airmak2@unl.edu; Shashi Verma, School of Natural Resources, sverma1@unl.edu; Derrel Martin, Biological Systems Engineering, dmartin2@unl.edu 
Description Efficient use of water resources in semi-arid agro-ecosystems of Nebraska is an important issue because of the rapid depletion of freshwater resources and drought conditions, and degradation of groundwater quality in recent years. Proper planning and management, and related policy decisions of water resources require accurate quantification of evapotranspiration (ET). An extensive field campaign has been initiated with the Central Platte Natural Resources District and UNL in the Central Platte River Valley to measure ET and other surface energy fluxes for various vegetation surfaces. The vegetation surfaces include, center pivot-irrigated grassland, rainfed grassland, rainfed winter wheat, center pivot-irrigated alfalfa, Phragmites australis-dominated cottonwood and willow stand plant community, irrigated maize, irrigated soybeans. A deluxe version of Bowen ratio energy balance systems are being used to measure ET and other surface energy balance components, soil moisture, and plant physiological parameters in each research site.
Project Support Central Platte Natural Resources District
Project Website
Report
Current Status Underway
Topic Crop Water Use and Water Use Efficiency
Project's Primary Contact Information
Name Allen, Craig (advisor)
Unit Nebraska Cooperative Fish and Wildlife Research Unit
Email callen3@unl.edu
Phone 402-472-0229
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=647
Project Information
Title Agricultural Landuse Change Impacts on Bioenergy Production, Avifauna and Water Use in Nebraska's Rainwater Basin
Other(s) Daniel Uden, School of Natural Resources, daniel.uden@huskers.unl.edu; Rob Mitchell, USDA-ARS; Tim McCoy, Nebraska Game and Parks Wildlife Division; Qinfeng Guan, School of Natural Resources, qguan2@unl.edu 
Description

This study addressed how the conversion of marginally productive agricultural lands in the Rainwater Basin region of south-central Nebraska, U.S.A. to bioenergy switchgrass (Panicum virgatum) might impact ethanol production, grassland bird populations and agricultural groundwater withdrawals. This study also used multi-model inference to develop predictive models explaining annual variation in springtime wetland occurrence and flooded area in the Rainwater Basin.

Results suggest that cellulosic ethanol production from switchgrass and residual maize (Zea mays) stover within existing starch-based ethanol plant service areas is feasible at current feedstock yields, removal rates and bioconversion efficiencies. Throughout the Rainwater Basin, the replacement of marginally productive rowcrop fields with switchgrass could increase ethanol production, conserve groundwater and benefit grassland birds under novel future climatic conditions. However, converting Conservation Reserve Program (CRP) grasslands to switchgrass could be detrimental to grassland bird populations. Predictive wetland inundation models suggest that surrounding agricultural landuse, wetland hydric footprint shape complexity, and autumn and winter precipitation and temperature are strong drivers of springtime wetland occurrence and flooded area in the Rainwater Basin.

Under a modest change scenario, 350 wells on rowcrop fields converted to switchgrass could cease groundwater pumping, conserving 52,064 acre-feet of water annually (2.6% of regional pumping capacity).

Under a extreme change scenario, 737 wells on rowcrop fields converted to switchgrass could cease groundwater pumping, conserving 112,827 acre-feet of water annually (5.6% of regional pumping capacity).

In areas at higher risk for additional irrigation limitations, agriculture groundwater use under the modest change and extreme change scenarios could decrease by 9.6% and 19.1%, respectively.

Click here to read a journal article about this research

Project Support U.S. Geological Survey, Great Plains Landscape Conservation Cooperative
Project Website http://snr.unl.edu/aboutus/who/people/graduatestudent-member.asp?pid=1373#tab1
Report Uden Landuse Change.pdf
Current Status Completed
Topic Drought
Project's Primary Contact Information
Name Hanson, Paul
Unit School of Natural Resources
Email phanson2@unl.edu
Phone 402-472-7762
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=758
Project Information
Title Pre-Historic Drought Records from the Eastern Platte River Valley
Other(s) R. Matt Joeckel, School of Natural Resources, rjoeckel3@unl.edu; Aaron Young, School of Natural Resources, ayoung3@unl.edu 
Description Recent studies have related large-scale dune activity in the Nebraska Sandhills and elsewhere on the western Great Plains to prehistoric megadroughts. At the eastern margin of the Great Plains, however, little or no effort has been expended toward identifying the impacts and severity of these climatic events. The eastern margin of the Great Plains should be of particular interest in paleclimate studies because it represents an important biogeographic boundary that may have shifted over time. In dunes around the present confluence of the Loup and Platte Rivers near Duncan, Nebraska, optical dating contrains, for the first time, the chronology of dune activity in the central-eastern margin of the Great Plains. A total of 17 optical age estimates taken from dune sediments clearly indicate two significant periods of dune activation at 5,100 to 3,500 years ago and 850-500 years ago. These reconstructed time intervals overlap both periods of large-scale dune activity in the Nebraska Sandhills and ancient droughts identified from other paleoclimate proxy records on the western Great Plains. The agreement between results from the eastern margin of the Great Plains and data from farther west indicate that megadroughts were truly regional in their effect. In order to further test a hypothesis of geographically-widespread megadrought effects, future work will date other dune deposits in eastern Nebraska from sites along the Loup and Elkhorn Rivers, as well as dunes in east-central Kansas and western Iowa.
Project Support United States Geological Survey Statemap Program
Project Website
Report Hanson Eastern Platte Valley.pdf
Current Status Published in Geomorphology 103 (2009) 555-561
Topic Extension
Project's Primary Contact Information
Name Skipton, Sharon
Unit Southeast Research and Extension Center
Email sskipton1@unl.edu
Phone 402-472-3662
Web Page http://www.southeast.unl.edu/staffdir/Skipton_Sharon
Project Information
Title Southeast Research and Extension Center
Other(s) Gary Zoubek, York County Extension, gzoubek@unl.edu 
Description Each day University of Nebraska Extension makes a difference in the lives of adults and youth. The faculty and staff in the Southeast Research and Extension Center and the 28 County Offices work to bring relevant researched based information to people in communities, towns and urban centers. Our efforts rely increasingly on partnerships with government agencies, business, industry, schools and community organizations. Working together with our partners Extension strives to strengthen the social, economic and environmental base of Nebraska's communities. Our programs must be ever-changing as Extension listens and responds to issues as they evolve. The Southeast Research and Extension District is unique because it serves both urban and rural communities Nebraska. The faculty and staff are committed to bringing the resources of the University and its research based information to the individuals and communities of Southeast Nebraska.
Project Support Varies according to program and project - for more information see http://www.southeast.unl.edu/
Project Website http://www.southeast.unl.edu/
Report
Current Status Continuous
Topic Groundwater
Project's Primary Contact Information
Name Perera-Estrada, Hugo
Unit Agronomy and Horticulture
Email hpereaestrada2@unl.edu
Phone 402-472-6085
Web Page
Project Information
Title Modeling Groundwater Nitrate Transport Beneath a Ground Water Quality Management Area in the Central Platte Region of Nebraska
Other(s) Mary E. Exner, School of Natural Resources, mspalding1@unl.edu; Roy Spalding, Agronomy and Horticulture, rspalding1@unl.edu 
Description A Ground Water Quality Management Area (GWQMA) is being evaluated to determine the effectiveness of producer practices in reducing high nitrate levels that result from excessive N-fertilizer and irrigation water applications. The assessment of nitrate movement in the primary and secondary aquifer relies on simulating groundwater flow and contaminant transport beneath the 588 km2 Phase III GWQMA. The Platte River is in hydraulic connection with the aquifer and forms the southern boundary of the model. The northern boundary parallels the northern edge of the GWQMA. Hydraulic conductivities from test hole data, irrigation well pedigree information and nitrate concentrations from 1988 to 2003 were input to a 3-D groundwater finite difference model. A Neumann or second-type boundary condition was established for the northern and southern model boundaries. Prescribed heads (Dirichlet-type boundary condition) were imposed on the upgradient and downgradient sides of the GWQMA. The thicknesses of the primary (upper) and secondary aquifers are somewhat variable in the investigated area as are hydraulic conductivities in the secondary aquifer. The groundwater model was calibrated in the steady-state mode with hydraulic head data from 1988 to 2003. The flow path and travel times within the study area result in an approximate evaluation of the susceptibility to nitrate contamination with transport. Results are described in 2-D and 3-D graphical visualizations. Hydraulic head and water quality data from adjacent monitoring wells screened in either the primary or secondary aquifers were used to quantify nitrate transport between the aquifers.
Project Support n/a
Project Website http://www.usawaterquality.org/conferences/2009/PDF/CEAP-all/Perera-Estrada09.pdf
Report
Current Status Completed
Topic Groundwater
Project's Primary Contact Information
Name Spalding, Mary Exner
Unit School of Natural Resources
Email mspalding1@unl.edu
Phone 402-472-7547
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=111
Project Information
Title Evaluation of the Effectiveness of Selected Farm Practices in Reducing Groundwater Nitrate
Other(s) Hugo Perera-Estrada, Agronomy and Horticulture, hpereaestrada2@unl.edu; Megan L. Liedte, Statistics; Roy Spalding, Agronomy and Horticulture, rspalding1@unl.edu 
Description Data from 25,961 producer reports and 1,935 irrigation wells were used to assess the effectiveness of management practices within 588 km2 of intensely irrigated corn production in the Platte River drainage in central Nebraska. The area has been regulated as a Phase III Ground Water Quality Management Area by the local Natural Resources District (NRD) for 19 years. The initial spatial analysis of the 1987 groundwater nitrate concentrations revealed an obvious concentration demarcation. Concentrations in the very contaminated northern area averaged 25.7 mg NO3-N/L while those in the southern portion averaged 9.4 mg NO3-N/L. Groundwater nitrate concentrations in the north are significantly correlated with time (r2 = 0.87) and decreased at an average annual rate of 0.24 mg NO3-N/L between 1987 and 2005. No significant concentration trend occurred in the southern area. During the 19 years the amount of N removed in grain increased at an average annual rate of 2 kg N/ha. In the north the association between the increase in N removed in grain and decrease in groundwater NO3-N concentrations is significant. The acreage converted from furrow to sprinkler irrigation increased threefold between 1988 and 2003. In the north the increase in sprinkler-irrigated acres is associated with the decrease in groundwater NO3-N concentrations. The NRD- recommended N-fertilizer rate for each corn field in the Phase III area is based upon a realistic yield goal and NRD-modified university N-fertilizer recommendation with credits for residual soil N and N available in irrigation water. From 1988 to 2003 N-fertilizer rates on 62 to 88% of the fields were within ± 56 kg N/ha (50 lb N/ha) of the NRD recommendation. The remaining fields were more likely to be fertilized at rates greater than 56 kg N/ha in excess of the recommendation than receive N at rates more than 56 kg N/ha below the NRD recommendation.
Project Support n/a
Project Website http://www.usawaterquality.org/conferences/2009/PDF/CEAP-all/Exner09.pdf
Report
Current Status Completed
Topic Hydrology
Project's Primary Contact Information
Name Chen, Xun-Hong
Unit School of Natural Resources
Email xchen2@unl.edu
Phone 402-472-0772
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=19
Project Information
Title Investigation of Stream-Aquifer Hydrologic Relationship for Clear Creek in Polk and Butler Counties
Other(s) Weihong Dong, Jilin University; Zhaowei Wang, School of Natural Resources; Gengxin Ou, School of Natural Resources; Can Liu, School of Natural Resources, can.liu1989@huskers.unl.edu 
Description

Vertical hydraulic conductivities (Kv) of both streambed and point bars can influence water and solute exchange between streams and surrounding groundwater systems. The sediments in point bars are relatively young compared to the older sediments in the adjacent aquifers but slightly older compared to submerged streambeds. Thus, the permeability in point bar sediments can be different not only from regional aquifer but also from modern streambed. However, there is a lack of detailed studies that document spatial variability of vertical hydraulic conductivity in point bars of meandering streams. In this study, the authors proposed an in situ permeameter test method to measure vertical hydraulic conductivity of the two point bars in Clear Creek, Nebraska, USA. We compared the Kv values in streambed and adjacent point bars through 45 test locations in the two point bars and 51 test locations in the streambed.

The Kv values in the point bars were lower than those in the streambed. Kruskal–Wallis test confirmed that the Kv values from the point bars and from the channel came from two statistically different populations. Within a point bar, the Kv values were higher along the point bar edges than those from inner point bars. Grain size analysis indicated that slightly more silt and clay particles existed in sediments from inner point bars, compared to that from streambed and from locations near the point bar edges. While point bars are the deposits of the adjacent channel, the comparison of two groups of Kv values suggests that post-depositional processes had an effect on the evolution of Kv from channel to point bars in fluvial deposits.

We believed that the transport of fine particles and the gas ebullition in this gaining stream had significant effects on the distribution of Kv values in a streambed-point bar system. With the ageing of deposition in a floodplain, the permeability of point bar sediments can likely decrease due to reduced effects of the upward flow and gas ebullition.

Project Support Upper Big Blue Natural Resources District, Chinese Ministry of Education, National Natural Science Foundation of China
Project Website
Report Chen_Hydraulic_Conductivity.pdf
Current Status Completed
Pic 1 Project Image
Pic Caption 1 Map showing the study site in Clear Creek, Nebraska 
Pic 2 Project Image 2
Pic Caption 2 Schematic for the in situ permeameter test in the point bars 
Topic Hydrology
Project's Primary Contact Information
Name Chen, Xun-Hong
Unit School of Natural Resources
Email xchen2@unl.edu
Phone 402-472-0772
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=19
Project Information
Title Hydrologic Connections in the Central Platte River Basin
Other(s) Mark E. Burbach, Conservation and Survey Division, mburbach1@unl.edu; Cheng Cheng, School of Natural Resources, ccheng2@unl.edu 
Description

The hydrologic properties of channel sediments have an important role in controlling hydrologic process in streams. This study focused on the water exchange between a stream and an aquifer induced by groundwater withdrawal, with the purpose of investigating the interbedded feature of channel sediments and to evaluate its effects on the calculation of streamflow depletion. Field work was conducted at nine study sites between Kearney and Columbus during the summers of 2005 and 2006. Direct-push techniques were used to produce electrical conductivity logs and to collect sediment cores. Permeameter tests were conducted on the sediment cores. Stream-aquifer simulation models were used to evaluate streamflow depletion for various types of channel sediments.

Sediment core samples were categorized into four groups:

  • sand and gravel,
  • sand and gravel with interbedded silt and clay layers,
  • fine sand with silt or clay layers, and
  • silt and clay with some sand and gravel.

In general coarse sediments occur in the western part of the study area, and the amount of fine sand, silt and clay increases eastward along the river. However, the sediments in the top two meters are about the same for all the sites, consisting mainly of sand and gravel.

Project Support Central Platte Natural Resources District, Upper Big Blue Natural Resources District, U.S. Geological Survey (through the University of Nebraska-Lincoln Water Center), U.S. Environmental Protection Agency
Project Website
Report Chen Hydrologic Connections.pdf
Current Status Published in Journal of Hydrology 2008 352:250-266
Topic Hydrology
Project's Primary Contact Information
Name Chen, Xun-Hong
Unit School of Natural Resources
Email xchen2@unl.edu
Phone 402-472-0772
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=19
Project Information
Title Hydrologic Connections in the Big and Little Blue River Basins
Other(s) Cheng Cheng, School of Natural Resources, ccheng2@unl.edu 
Description Over extraction of groundwater near a stream can lower stream stage and induce streamflow depletion when the stream and aquifer are hydrologically connected. The Little Blue River Basin is an area of intensive groundwater development for irrigation, and the streamflow depletion in this basin was determined by an analog model (Emery, 1966). However, the post audit of the model (Alley and Emery, 1986) suggested that the decline of water-levels was overestimated and streamflow depletion was underestimated. Therefore, it is necessary to re-evaluate stream-aquifer interactions in the basin. In this study, an area is chosen for this analysis from the basin and three main streams -- the Little Blue River, Big Sandy Creek, and Spring Creek are included. Channel sediments and structures play an important role in determining stream-aquifer interactions. Firstly, field and laboratory methods including geoprobe logging and permeameter tests are utilized to investigate the channel deposits in the three main streams in the Little Blue River Basin. Results show that channels have low hydraulic-permeable layers which reduce their hydraulic connections to the adjacent aquifers. Secondly, a groundwater flow model is constructed to identify the hydraulic properties of the aquifer and evaluate streamflow depletion under groundwater withdrawals in the study area. Modeling results indicate that streamflow depletion is very low and aquifer storage loss is the main source of groundwater pumpage.
Project Support Upper Big Blue Natural Resources Distrect, Lower Big Blue Natural Resources District, Little Blue Natural Resources District
Project Website
Report
Current Status Completed
Topic Hydrology
Project's Primary Contact Information
Name Chen, Xun-Hong
Unit School of Natural Resources
Email xchen2@unl.edu
Phone 402-472-0772
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=19
Project Information
Title Groundwater Flow Model for the Lower Platte North Natural Resources District
Other(s) Cheng Cheng, School of Natural Resources 
Description Compared to other parts of Nebraska, the Platte River is wide and thus it is more challenging to characterize its hydrologic connections with the surrounding aquifers. The shallow aquifer consists of the alluvial and glacial deposits and displays strong heterogeneity. A three-dimensional groundwater flow model is developed using Visual MODFLOW to evaluate the impacts of groundwater withdrawals on the stream-aquifer system in the Lower Platte River Basin. The study area is about 65 miles by 50 miles and is located in eastern Nebraska. Two pumping tests were conducted to determine the hydraulic properties of the aquifers and aquitards, which are beneficial for model calibration. In-situ and laboratory permeameter tests of streambed sediments in the Platte River were per-formed to determine the streambed vertical hydraulic conductivity (Kv) values, which play an important role in controlling stream-aquifer interactions. The ground-water flow model integrates the geological, hydrological, precipitation, and soil information. The test-hole logs combining with the irrigation well logs were used to define the hydrostratigraphic units. The model is divided into 5 layers with 201 columns and 195 rows in each layer. The Platte River is simulated by the constant-head boundary package in MODFLOW. The model is calibrated using the groundwater level measurements of the USGS and local Natural Resources District observation wells from January 1950 to December 2004. The time interval of the calibration is divided into 660 stress periods, and each stress period consists of 10 time steps. Trial-and-error calibration is used to determine the hydraulic conductivity, specific yield, and specific storage of the aquifers and aquitards. Furthermore, the values of groundwater recharge and evapotranspiration are estimated by model calibration. After the model is well calibrated, it is used to determine the impacts of groundwater pumping over the 55 year periods on the streamflow in the Platte River.
Project Support Lower Platte North Natural Resources District
Project Website
Report
Current Status Underway
Topic Hydrology
Project's Primary Contact Information
Name Cheng, Cheng
Unit School of Natural Resources
Email ccheng2@unl.edu
Phone 402-472 0772
Web Page http://snr.unl.edu/aboutus/who/people/graduatestudent-member.asp?pid=798
Project Information
Title Statistical Distribution of Streambed Vertical Hydraulic Conductivity along the Platte River, Nebraska
Other(s) Xun-Hong Chen, School of Natural Resources, xchen2@unl.edu, Jinxi Song, Deming Wang 
Description Streambed vertical hydraulic conductivity (Kv) plays an important role in understanding and quantifying the stream-aquifer interactions. While several researchers have discussed the spatial variability of streambed horizontal hydraulic conductivity or Kv at one or several close-located sites in a river, they did not develop any statistical distribution analysis of streambed Kv at distant sites along a large river. In this paper, the statistical distribution and spatial variation of streambed Kv at 18 test sites in a 300-km reach of the Platte River in Nebraska are presented. Insitu permeameter tests using the falling-head method were carried out to calculate the streambed Kv values. Fine-grained sediments transported by two tributaries, the Loup River and the Elkhorn River, to the Platte River appear to result in lower streambed Kv values downstream of the confluences between the Platte River and the tributaries. The streambed Kv values were found to be normally distributed at nearly each test site. When the correlated Kv values were eliminated from the grid sampling plots, the remaining independent sub-datasets of streambed Kv values were still in normal distribution at each test site. Furthermore, the combined streambed Kv values upstream of the first confluence between the Platte River and the Loup River was normally distributed, which may be due to the lack of tributaries in-between and thus streambed sediments were well distributed in this reach and belonged to a single population of hydraulic conductivity values. In contrast, the combined dataset of all measurements conducted downstream of this confluence was no longer in normal distribution, presumably as a result of the mixing of different sediment sources.
Project Support Lower Platte North Natural Resources District, Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China
Project Website
Report Cheng_Distribution.pdf
Current Status Published in Water Resources Management DOI 10.1007/s11269-010-9698-5
Topic Hydrology
Project's Primary Contact Information
Name Korus, Jesse
Unit Conservation and Survey Division
Email jkorus3@unl.edu
Phone 402-472-7561
Web Page http://snr.unl.edu/aboutus/who/people/staff-member.asp?pid=1010
Project Information
Title Eastern Nebraska Water Resources Assessment (ENWRA)
Other(s)

Paul Hanson, School of Natural Resources / Conservation and Survey Division, phanson2@unl.edu; Sue Lackey, School of Natural Resources / Conservation and Survey Divison, slackey1@unl.edu; Matt Marxsen, School of Natural Resources / Conservation and Survey Division, mmarxsen2@unl.edu

Dana Divine, ENWRA Project Coordinator, ddivine@lpsnrd.org

Visit the Nebraska Maps and More website (http://nebraskamaps.unl.edu/home.asp) to order an excellent publication that describes this project more in-depth, Bulletin 1: Eastern Nebraska Water Resources Assessment (ENWRA) Introduction to a Hydrogeological Study.

 
Description

Eastern Nebraska contains 70% of the state's population, but is most limited in terms of the state's groundwater supplies. The population in this region is expected to increase; thus the need for reliable water supplies is paramount. Natural resources districts (NRDs), charged with ground water management in Nebraska, seek to improve their management plans in response to growing populations, hydrologic drought, and new conjunctive management laws. Detailed mapping and characterization is necessary to delineate aquifers, assess their degree of hydrologic connection with streams and other aquifers, and better predict water quality and quantity.

In a collaborative effort between local, state, and federal agencies, the ENWRA project has been initiated to gain a clearer understanding of the region's groundwater and interconnected surface water resources. These resources can be difficult to characterize because of the complex geology created by past glaciations. Acquiring geologic and hydrologic data in the eastern, or glaciated, part of Nebraska requires the use of multiple, innovative techniques. Currently, little is known about which techniques are most effective and feasible. Once identified, the most effective and feasible tools will be used to provide data, interpretations, and models for improved water resources management.

The ENWRA group has established three pilot test sites for intensive study using a variety of investigative techniques. The goal of the initial work being done at the three pilot test sites is to determine the location, extent, and connectivity of aquifers with surface waters, with the hope of expanding these investigative techniques across other portions of eastern Nebraska. The pilot test sites are located near Oakland, Ashland, and Firth with each site exhibiting differing geologic conditions. The techniques that will be utilized in the study include: 1) helicopter electromagnetic (HEM) surveys; 2) ground-based geophysical surveys; 3) test hole drilling; and 4) geochemical analysis, just to name a few. So far HEM surveys were completed over approximately one township at each site. Other techniques were used to provide "ground truth" data to support the HEM interpretations.

The agencies involved in the ENWRA are:

  • Lower Platte South Natural Resources District
  • Lower Platte North Natural Resources District
  • Papio Missouri River Natural Resources District
  • Lower Elkhorn Natural Resources District
  • Lewis and Clark Natural Resources District
  • Nemaha Natural Resources District
  • United States Geological Survey
  • University of Nebraska Lincoln Conservation and Survey Division
  • Nebraska Department of Natural Resources
  • Nebraska Department of Environmental Quality
Project Support Nebraska Department of Natural Resources Interrelated Water Management Plan/Program
Project Website http://www.enwra.org/
Report
Current Status HEM surveys are complete and 3-D aquifer diagrams have been prepared. Report Status: Ashland area report has been prepared and is under review and the Firth area report is being written.
Pic 1 Project Image
Pic Caption 1 Eastern Nebraska Water Resources Assessment (ENWRA) Study Sites. 
Topic Invasive Species
Project's Primary Contact Information
Name Allen, Craig (advisor)
Unit Nebraska Cooperative Fish and Wildlife Research Unit
Email callen3@unl.edu
Phone 402-472-0229
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=647
Project Information
Title The Effect of Common Reed (Phragmites australis) on River Otter (Lontra canadensis) Habitat Use
Other(s) Amy Williams, amy_ruth18@hotmail.com; Sam Wilson, Nebraska Game and Parks Commission, sam.wilson@nebraska.gov 
Description The river otter (Lontra canadensis) is a threatened species in Nebraska and little is known about its local ecology. The recent invasion of the Platte River by the common reed (Phragmites australis) has altered the riverscape and could have negative effects on otters. Since the reintroduction of river otters to several of Nebraska's river basins beginning in the late 1980's, there have been no quantitative studies examining the status of the population or habitat use of river otters in the state. The recent invasion of P. australis in the Big Bend region of the Platte River has made the need to fill this knowledge gap more critical. We are examining the effects of P. australis on river otters by determining if otters use river ways dominated by P.australis or den in areas of P. australis more or less than expected relative to availability. Sixteen otters were trapped, radio tagged, and tracked between 2006 and 2009. 517 den/resting locations were identified, 127 of which were unique locations. Den/resting site habitat use was compared to availability to determine if otters were using P. australis in proportion to availability. Females use unique sites in P. australis more than expected but males do not. When all locations were analyzed, both males and female used P. australis in proportion to availability. P. australis provides cover for females and is likely used for resting locations when traveling with pups. Information on otter abundance and habitat use from this study will support the creation and implementation of a state river otter management plan and ensure the persistence of a viable otter population in Nebraska.

Project Support

Nebraska Cooperative Fish and Wildlife Research Unit, Nebraska Game and Parks Commission
Project Website http://snr.unl.edu/necoopunit/research.main.html#river_otters
Report
Current Status Completed
Topic Property Values
Project's Primary Contact Information
Name Shultz, Steve
Unit UNO Real Estate Research Center
Email sshultz@mail.unomaha.edu
Phone 402-554-2810
Web Page http://cba.unomaha.edu/dir/HomePageBio.cfm?id=347
Project Information
Title Ongoing UNO/UNL Research on the Determinants of Agricultural Land Values: How Irrigation Contributes to Land Values in Western and Central Nebraska
Other(s) Nick Schmitz, UNO Real Estate Research Center 
Description

Hedonic (mass appraisal) land valuation models were estimated in the Republican and Platte watersheds of Central and Western Nebraska. These models are based on assumption that the buyers and sellers of agricultural land are able to accurately assess the value of irrigation when negotiating sale contract prices, and that irrigation equipment can be distinguished from land and irrigation values. Alternative models were estimated using various combinations of explanatory variables (all measured at the parcel level of analysis). These include: soil productivity measures, topography precipitation, parcel size, cropping patterns, topography, aquifer thickness, well pumping capacity, distances to elevators and towns, and irrigation systems.

The location of all agricultural land sales statewide (2000-2007) and estimated irrigation values in the Platte and Republican Watersheds were identified. Preliminary mass appraisal model results were summarized in tables and the locations of retired irrigation parcels in the Republican Watershed (as part of a 2006 NE DNR and USDA Pilot Program) were identified. The value of irrigated cropland is on average $615/acre (this is the value of irrigated cropland only and does not include the value dryland corners within pivot systems). As well, there are numerous areas and site-specific parcels within the watershed with both lower and higher irrigation values. In fact, we have calculated irrigation values for all of the natural resource districts in the Republican watershed: they range from $488/acre to $948/acre. These estimates are still considered 'preliminary' and may be subject to revision. These irrigation values also do not account for premiums above and beyond marginal market values that farmers and landowners will likely require to willingly participate in future irrigation retirement programs.

More on this research in a journal of the Western Agricultural Economics Association

Project Support U.S. Department of Agriculture Water and Watershed Program
Project Website
Report
Current Status Complete (up to 2007)
Topic Riparian Vegetation Water Use
Project's Primary Contact Information
Name Kilic, Ayse
Unit Center for Advanced Land Management Information Technologies
Email akilic@unl.edu
Phone 402-472-5351
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=860
Project Information
Title Estimating Riparian Water Use: An Application of Remote Sensing
Description The goal of this project is to quantify riparian evapotranspiration (ET) by utilzing satellite and air-borne remote sensing data on selected watersheds in the North Platte River. The results will be used to develop guidelines on riparian water use.
Project Support UNL Office of Research Layman Award
Project Website
Report
Current Status Completed
Topic Riparian Vegetation Water Use
Project's Primary Contact Information
Name Kilic, Ayse
Unit Center for Advanced Land Management Information Technologies
Email akilic@unl.edu
Phone 402-472-5351
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=860
Project Information
Title Estimating Riparian Water Use: An Application of Remote Sensing
Description The goal of this project is to quantify riparian evapotranspiration (ET) by utilzing satellite and air-borne remote sensing data on selected watersheds in the North Platte River. The results will be used to develop guidelines on riparian water use.
Project Support UNL Office of Research Layman Award
Project Website
Report
Current Status Completed
Topic Survey
Project's Primary Contact Information
Name Joseph Hamm
Unit jhamm2@nebraska.edu
Phone 402-472-5678
Web Page http://ppc.unl.edu/
Project Information
Title Platte River Habitat Partnership Survey
Other(s) Lisa Pytlik Zillig, Public Policy Center, lpytlikz@nebraska.edu, Alan Tomking, Public Policy Center, atomkins@nebraska.edu 
Description

Nebraska’s native prairies are a valued resource and under constant anthropogenic demand and degradation. By engaging land owners in voluntary programs, the Platte River Habitat Partnership aims to restore and enhance this important natural resource. In this project, the Public Policy Center conducted a survey to assess land owners’ perceptions of the Platte River Habitat Partnership to help direct the Partnership’s second phase. Specifically, land owners who live in the region covered by the Partnership but did not participate, and those that did participate in the Partnership were surveyed in order to answer four key questions: 1. How knowledgeable are these land owners about the Partnership? 2. What is the nature of these land owners’ interactions with the Partnership? 3. How is the Partnership itself generally perceived by these land owners? 4. What would encourage land owners who had not participated in the Partnership to participate?

Project Support The Nature Conservancy
Project Website http://ppc.unl.edu/project/PlatteRiverHabitatPartnershipSurvey
Report PRHP_Report.pdf
Current Status Completed
Topic Water Quality
Project's Primary Contact Information
Name Riens, John
Unit Wisconsin Ecological Services Field Office, U.S. Fish & Wildlife Service
Email John_Riens@fws.gov
Phone 541-885-2503
Web Page http://www.fws.gov/
Project Information
Title Macroinvertebrate Response to Buffer Zone Quality in the Rainwater Basin Wetlands of Nebraska
Other(s) W. Wyatt Hoback, Biology UNK, hobackww@unk.edu; Matt Schwarz, U.S. Fish & Wildlife Service 
Description

The Rainwater Basin is one of the most endangered wetland ecosystems in North America. This ecosystem is critical to many species including migratory waterfowl. Land use and runnoff from agriculture and cattle confinement operations are likely to be reducing the basin's health and diversity, however little information exists concerning macroinvertebrates. Twenty-two locations were assessed for water quality parameters, vegetation composition, and macroinvertebrates identified to genus. Samples were collected biweekly starting in April through July for three years. Macroinvertebrate diversity was impacted in areas with little buffer although the effects were not pronounced. Institution of a more effective vegetative buffers strip may reverse this trend to improve ecosystem quality and provide for invertebrate resources for migratory birds.

Click here to see a poster about this research

Project Support n/a
Project Website
Report
Current Status Completed
Topic Water Quality
Project's Primary Contact Information
Name Tang, Zhenghong
Unit Architecture
Email ztang2@unl.edu
Phone 402-472-9281
Web Page http://architecture.unl.edu/people/bios/tang_zhenghong.shtml
Project Information
Title Assessment of Sedimentation and Water Quality Conditions in the Rainwater Basin's Playa Wetlands
Other(s) Mark Kuzila, School of Natural Resources, mkuzila1@unl.edu; Xu Li, Department of Civil Engineering, xuli@unl.edu; Amy Burgin, School of Natural Resources, aburgin2@unl.edu 
Description

The overall goal of this project is to prioritize watershed restoration/acquisition programs in the Rainwater Basin (RWB) by examining playa wetlands’ sedimentation and water quality conditions using the Revised Universal Soil Loss Equation 2 (RUSLE2) and the fly ash technology.

Three specific tasks are included in this project:

  1. Calculate and map the sedimentation rates and the age of deposition for all playa wetlands in RWB
  2. Consolidate existing water quality data of the RWB playa wetlands and evaluate the key factors influencing playa wetland water quality
  3. Assess the effects of sedimentation control practices and prioritize future watershed restoration/acquisition programs

The final products of this project include:

  1. An atlas of wetland sedimentation maps and a risk report highlighting the areas in watersheds with the highest sedimentation rates
  2. A geodatabase and an evaluation report on the water quality conditions of the playa wetlands in the RWB
  3. A written assessment report for sedimentation control practices and a watershed index to prioritize future conservation/acquisition programs
Project Support U.S. Environmental Protection Agency
Project Website http://www.unl.edu/playawetlands/
Report
Current Status Underway
Topic Watershed Management
Project's Primary Contact Information
Name Jenkins, Allan
Unit Economics
Email
Phone
Web Page
Project Information
Title Middle Platte Socioeconomic Overview
Description This report was published in February 1999 and designed to provide a common body of knowledge to all groups engaged in decisions regarding the Platte River. Recognizing that different decision-makers have different levels of prior knowledge concerning the Platte River, the author attempted to create a document suitable for a range of audiences that also facilitated discussion.
Project Support U.S. Environmental Protection Agency
Project Website http://watercenter.unl.edu/PRS/PlatteRiverReports/The%20Platte%20Watershed%20Program.pdf
Report
Current Status Completed
Topic Wetlands
Project's Primary Contact Information
Name Tang, Zhenghong
Unit Architecture
Email ztang2@unl.edu
Phone 402-472-9281
Web Page http://architecture.unl.edu/people/bios/tang_zhenghong.shtml
Project Information
Title Developing LiDAR-Derived Wetland Maps To Assess Conservation Design Practices For Playa Wetlands In Rainwater Basin
Other(s) Ed Harvey, School of Natural Resources, feharvey1@unl.edu; Xu Li, Department of Civil Engineering 
Description The overall goal of this project is to provide wetland managers with topographically-correct 3-D wetland maps to prioritize wetland conservation efforts and assess wetland conservation design practices. This project addresses three specific tasks for the playa wetlands: 1) Establish accurate, topographically-correct, 3-D wetland maps to relate weather conditions and wetland functions; 2) Develop a measurable Restorable Wetland Index to prioritize playa wetland and drainages conservation; 3) Assess wetland conservation design practices for watershed-based wetland conservation. This research will use high-resolution Light Detections And Ranging (LiDAR) data to create next-generation wetland maps for playa wetlands. The research provides the missing link in conservation design as these data will provide accurate elevation measures to delineate watershed extent and determine the impact of individual hydrologic modifications. This project will be one of the first to integrate LiDAR data and a hydrologic modifications datasets to find the relations of current weather conditions and wetland functions. This project provides reliable, accurate wetland spatial parameters to prioritize playa wetland conservation and assess the effectiveness of existing wetland conservation design practices. The wetland conservation design tools and protocols will be examined in two pilot counties in Nebraska. The intellectual merit of the research is based on advancing knowledge linkage of wetland mapping technologies and wetland function modifications, and showing how to adapt wetland conservation designs. The outputs from this project provide practical protocols for state/regional/local wetland managers and thus ensure "no net loss" in quality and quantity of wetlands.
Project Support US EPA
Project Website
Report
Current Status Completed
Topic Wildlife
Project's Primary Contact Information
Name Pegg, Mark (advisor)
Unit Nebraska Cooperative Fish and Wildlife Research Unit
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 Catfish Population Dynamics in the Platte River, Nebraska
Other(s) Tony J. Barada, abarada2@unl.edu 
Description

Catfish angling is popular throughout the United States and catfish are the most sought after fish species in the Platte River. However, catfish management in the Platte River is minimal as little is known about current populations. The objective of this study was to determine the current status of channel catfish and flathead catfish populations in the central and lower Platte River. Specifically, the study evaluated population characteristics including relative abundance, size structure, condition, age, growth and mortality.

Channel catfish are much more abundant than flathead catfish in the Platte River. The current Platte River channel catfish population appears to be average, comparable to many Nebraska and Midwestern rivers. Population characteristics displayed considerable variation along the Platte River and some longitudinal patterns were evident. Channel catfish in the central Platte River had lower relative abundances, higher condition, greater size structure, faster growth and lower mortality compared to lower Platte River channel catfish. Key factors likely influencing differences in channel catfish population characteristics are prey availability, flow modifications, habitat characteristics, tributary inflows and angler exploitation. Water manipulations from the Loup River Power Canal were also identified as a possible negative influence on lower Platte River channel catfish populations because hydropeaking is likely creating a stressful environment. However, channel catfish in the central Platte River appear to have benefited from recent high flows that likely increased productivity and food availability in the central Platte River.

Tony Barada's Master's Thesis on Catfish Population Dynamics in the Platte River

Project Support Nebraska Game and Parks Commission, Federal Aid in Sportfish Restoration
Project Website
Report
Current Status Graduate thesis project completed - thesis available at UNL CY Thompson Library (Call # LD3656 2009 .B373)
Topic Wildlife
Project's Primary Contact Information
Name Vivian, Lindsay A.
Unit Biology, UNK
Email lindsayviv@gmail.com
Phone 308-379-4587
Web Page
Project Information
Title Updating the Distribution and Population Status of the Platte River Caddisfly
Other(s) W. Wyatt Hoback, Biology UNK, hobackww@unk.edu 
Description The Platte River caddisfly, Ironoquia plattensis, was first described in 1999 from a warm water slough just south of Grand Island, NE. Using a benthic core sampling method, the investigators reported an average caddisfly larval density of 805 ± 194/m2. In 2004, there were no Platte River caddisflies observed at the 1999 study site. Ironoquia plattensis has been observed at five other locations in the central Platte region, but only two of the six historic populations are considered stable. Between 2002 and 2005, central Nebraska suffered an extensive drought, which could have taken its toll on the caddisfly. The sloughs where Ironoquia plattensis occur are typically wet nine months out of the year and dry during the summer. During the summer of 2009, four historic sites and one new, previously unrecorded site were sampled for larvae using a 30 cm D-frame net to sample a one meter swath a minimum of four times from each location. Using a GIS (Geographic Information Systems) predictive model and Google Earth, additional areas are being surveyed for the presence of the Platte River Caddisfly. The GIS model was created using local groundwater data from 1999 to the present, a soils layer, high resolution imagery, and a vegetation map analysis. If more populations are found, transects will be set up on the slough banks, and a quadrat will be used to quantify larval abundance in these areas. This will also be done at all historic locations. The goal is to establish the population status of this very rare insect of Nebraska which is adapted to the seasonal flows of the Platte River.

Lindsay Vivian's Master's Thesis on Platte River Caddisfly

For more information, read this journal article in the Annals of the Entomological Society of America

Project Support US Fish and Wildlife Service
Project Website
Report
Current Status In progress