NU Water-Related Research in District 36

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 38 records found for District 36


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 Nutrient Use
Project's Primary Contact Information
Name Schepers, Jim
Unit Agronomy and Horticulture
Email Jim.Schepers@ARS.USDA.GOV
Phone 402-472-1513
Web Page http://www.agronomy.unl.edu/newfacultystaff/directory/schepers.html
Project Information
Title Managing Nitrogen Fertilizer Applications to Protect Groundwater
Description USDA-ARS scientists have research projects near Shelton, near Giltner, and about seven miles north of Central City which deal with protecting groundwater by carefully managing nitrogen fertilizer applications to corn and wheat. One cropping system involves seed corn production, which is assumed to be environmentally unfriendly. Our strategy is to plant wheat as a scavenger crop after the seed corn is harvested. In early June, soybeans are inter-seeded into the wheat. Both wheat and soybean function as scavenger crops and essentially eliminate the potential for nitrate leaching. A component of this management strategy is to use active (no sunlight required) crop canopy sensors to monitor plant chlorophyll (greenness) and biomass (vigor) while driving through the field to determine if more nitrogen is required by wheat or corn and automatically applying additional fertilizer while at that spot in the field. These technologies allow producers to use the crop as a bio-sensor of nitrogen needs and optimize nitrogen supplied by other sources (soil organic matter, manure, irrigation water).
Project Support U.S. Department of Agriculture - Agricultural Research Service
Project Website http://www.nue.okstate.edu/
Report
Current Status n/a
Topic Crop Nutrient Use
Project's Primary Contact Information
Name Wortmann, Charles
Unit Agronomy and Horticulture
Email cwortmann2@unl.edu
Phone 402-472-2909
Web Page http://agronomy.unl.edu/wortmann
Project Information
Title Nitrogen Use Efficiency of Irrigated Corn for Three Cropping Systems in Nebraska
Other(s) Charles Shapiro, Agronomy & Horticulture, cshapiro@unl.edu; Richard Ferguson, Agronomy & Horticulture, rferguson1@unl.edu; Gary Hergert, Panhandle Research & Extension Center, ghergert1@unl.edu 
Description

Overview Nitrogen fertilizer will continue to be indispensible for meeting global food, feed, and fiber needs. Voroneyand Derry (2008) estimated that 340 million Mg yr-1 N is fixed by natural means, including lightning and biological N fixation, and 105 million Mg yr-1 is fixed by human activities, including burning of fossil fuels and N fertilizer production, with N fixation by human activities expected to continue to increase. Townsend and Howarth (2010) estimated the amount of N fixed by human activities to be about 180 million Mg yr-1, with most used as mineral fertilizer. Fertilizer N production has important environmental implications with an average of ~2.55 kg CO2 emitted per kg fertilizer N fixed and transported (Liska et al., 2009). Th e amount of N applied is associated with emission of N2O (IPCC–OECD, 1997) and N accumulation in sensitive aquatic, marine, and terrestrial ecosystems (Groffman, 2008; Malakoff , 1998). Th e challenge is to produce more grain to meet growing global needs with high NUE.

Conclusions Across diverse production environments, high corn yields can be achieved with efficient use of soil and applied N and without high risk of NO3 -N leaching to groundwater. With excellent farm management, recovery of applied fertilizer-N in high-yielding corn fields of Nebraska was well above 60 to 70% at the economically optimal nitrogen rate (EONR), resulting in low residual soil nitrate nitrogen (RSN) levels. Agronomic efficiency and crop partial factor productivity (PFP), the Nitrogen use efficiency (NUE) components most closely related to profitability of production, can also be high at EONR. Less preplant and more in-season N application may be especially important for drybean (CD) which had low recovery efficiency (RE) and much postharvest RSN compared with corn (CC) and soybean (CS). The levels of NUE achieved in our study for CC and CS far exceed current national or regional means, demonstrating the potential for high NUE with high yield corn production. Further NUE efficiency may be gained through more accurate in-season N application such as with use of the presidedress NO3 test (Andraski and Bundy, 2002) and spatial variation in N rate in response to variation in crop need, such as through use of reflectance sensors (Scharf and Lory, 2009; Barker and Sawyer, 2010; Roberts et al., 2010).

Project Support Nebraska State Legislature, Nebraska Agricultural Business Association
Project Website
Report Wortmann_NUE.pdf
Current Status Completed
Topic Crop Water Use
Project's Primary Contact Information
Name Cassman, Ken
Unit Agronomy and Horticulture
Email kcassman1@unl.edu
Phone 402-472-5554
Web Page http://agronomy.unl.edu/cassman
Project Information
Title Real-time Decision Support System for Deficit Irrigation - Hybrid-Maize
Other(s)  
Description

Hybrid-Maize is a computer program that simulates the growth of a corn crop under non-limiting or water-limited (rainfed or irrigated) conditions based on daily weather data. Specifically, it allows the user to:

  • assess the overall site yield potential and its variability based on historical weather data
  • evaluate changes in attainable yield using different combinations of planting date, hybrid maturity, and plant density
  • explore options for optimal irrigation management
  • conduct in-season simulations to evaluate actual growth up to the current date based on real-time weather data, and to forecast final yield scenarios based on historical weather data for the remainder of the growing season

Hybrid-Maize does NOT allow assessment of different options for nutrient management nor does it account for yield losses due to weeds, insects, diseases, lodging, and other stresses. Hybrid-Maize has been evaluated primarily in rainfed and irrigated maize systems of the U.S. Corn Belt. Caution should be exercised when applying this model to other environments as this may require changes in some of the default model parameters.

This project will develop a similar tool for irrigation scheduling for Nebraska soybean producers, and a real-time decision support system for deficit irrigation on corn, both based upon the Hybrid-Maize model. These tools will assist producers who have limited irrigation water supplies to optimize irrigation scheduling in real time for maximum yields, in particular during water-short years.

Project Support Nebraska Natural Resources Conservation Service, Nebraska Soybean Board
Project Website http://hybridmaize.unl.edu/
Report
Current Status Continuing - Software Available
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 Nebraska Agricultural Water Management Demonstration Network
Other(s) Gary Zoubek, York County Extension, gzoubek@unl.edu 
Description

The Nebraska Agricultural Water Management Demonstration Network (NAWMDN) encourages the adoption of newer technologies that will enable farmers to use water and energy resources associated with irrigated crop production efficiently. NAWMDN launched in 2005 and started with 20 growers from south central Nebraska who joined the Network as collaborators. In 2008 an online tool named ETgage was added to enable participation by growers throughout Nebraska.

The NAWMDN ETgage project is one part of a system for testing cutting-edge technologies and creating a network with growers, UNL Extension, NRDs, NRCS, and crop consultants, and other interested partners, that will enable the adoption of water and energy conservation practices. The simplicity of the use and interpretation of the ETgage data, as well as its economic feasibility, makes it easy for farmers to monitor crop water use for effective irrigation management. In this project ETgages are used to estimate crop water use, and Watermark sensors are used to measure soil moisture to determine irrigation timing and amount. Each year, NAWMDN team members organize educational meetings during the growing season and over the winter to implement the project, teach participants how to use the ETgage and Watermark sensors for irrigation management, review the results, set goals, and obtain grower feedback. This project has been reported at local, regional, and national meetings.

In 2005, there were 18 demonstration sites. Some of the ETgage and Watermark sensors were read by growers and some were read weekly by Network core members. In 2006, the second year of the project, there were more than 50 demonstration sites. In 2007 more than 125 cooperators in nine NRDs and 22 counties were involved. In the fall of 2007, 89 producers involved in the NAWMDN were surveyed; of those 56% responding, the estimated corn water savings varied from 0-7.5" with an average savings of 2.6," while soybeans water savings varied from 0-4.8" with an average of 2.1." Using 2007 diesel prices, this resulted in total energy savings of $2,808,000 and $2,269,800 for corn or soybeans over 117,000 acres.

In 2008 over 300 active participants from 25 counties in 9 of Nebraska's 23 NRDs. An interactive web site was also created to inform growers and other clients about the network and to educate producers and industry professionals about using these two tools along with crop stage of growth information to make irrigation management decisions. This interactive web site has engaged the cooperating producers and enhanced learning. The site consists of a map of Nebraska's 93 counties on which producers can select specific counties to find a Google gps map with ETgauge locations marked. Producers can click on specific sites to see the weekly reference evapoptranspiration (ET) reported by producers. The site also includes information about the NAWMDN and how to use the various tools.

For detailed information, see Nebraska Agricultural Water Management Demonstration Network: Integrating Research and Extension/Outreach.

Project Support Partners include personnel from 19 extension offices, the Little Blue NRD, the Upper Big Blue NRD, Nebraska Association of Resources Districts, Nebraska Natural Resources Conservation Service, South Central Agricultural Laboratory, and the Central Nebraska Public Power and Irrigation District.
Project Website http://water.unl.edu/cropswater/nawmdn
Report
Current Status Continuing
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 A Decision Support Tool to Increase Energy and Crop Water Use Efficiency for Corn and Soybean Production
Description

Energy costs coupled with limitations in water availability are threatening the sustainability of irrigation in the state. Energy costs for irrigation rose almost 100 percent for typical Nebraska irrigators from the spring of 2003 to the summer of 2006 and continue to rise sharply. The rising cost of fuel and the limited availability of water make producing maximum crop yield with minimal input imperative.

Nebraska growers need scientifically based and practical management strategies that can aid them in their decision-making process to enhance crop water-use efficiency and reduce energy use to achieve maximum profitability. Growers are looking for answers on how to make a maximum use of limited irrigation water and how to manage irrigation water to reduce pumping cost.

Crop simulation models with the capability of "real-time" assessment of crop and soil water status and yield prediction based on historical climate data represent a powerful new tool to help improve irrigation decisions and increase water-use efficiency especially for situations where the amount of available water supply is less than the full requirement for maximum crop yield. This project validates and demonstrates a decision-support tool for a real-time irrigation scheduling period, and releases the new tool as a software program for use by crop producers, crop consultants, and industry professionals. This tool will be used to assess energy requirement for different irrigation regimes to aid growers and state and federal agencies to make better-informed management decisions.

Project Support Upper Big Blue Natural Resources District, Gard Fund
Project Website
Report
Current Status Underway
Topic Crop Water Use
Project's Primary Contact Information
Name Martin, Derrel
Unit Biological Systems Engineering
Email dmartin1@unl.edu
Phone 402-472-1586
Web Page http://bse.unl.edu/dmartin2
Project Information
Title Enhancing Irrigation Management Tools and Developing a Decision System for Managing Limited Irrigation Supplies - Enhancing The Water Optimizer
Other(s) Chris Thompson, Agricultural Economics, cthompson2@unl.edu; Paul Burgener, Panhandle Research and Extension Center, pburgener2@unl.edu; Ray Supalla, Agricultural Economics, rsupalla1@unl.edu; Gary Hergert, Panhandle Research and Extension Center, ghergert1@unl.edu 
Description

The Water Optimizer is a computer model developed in response to several years of drought across the state and to farmers facing water restrictions. The model can be used by producers to evaluate management options when water is limiting due to drought or regulations; it can also be used by water planners or policy makers who wish to estimate the farm-level economic consequences of retiring acres or regulating the water supply. Released by UNL in 2005, the model is available for all counties in Nebraska to evaluate single fields for several crop options. Irrigated crops include: corn, soybeans, sorghum, wheat, alfalfa, edible beans and sunflowers. Dryland crops include: corn, soybeans, sorghum, sunflowers, alfalfa and wheat in continuous, summer fallow and eco-fallow rotations. Producers put information into a Microsoft Excel spreadsheet, including soil type and irrigation system options. Irrigation options include center pivot or gravity irrigation systems, well or canal delivery, and systems powered by electricity, diesel or natural gas. After entering this basic information, producers enter their production costs, irrigation costs, crop prices, crop type and available water. After these parameters have been set, the program calculates what crops will be most profitable with the given costs and available water. This gives the producer a "whole farm view" in considering how to manage available water supplies.

While the Water Optimizer is useful, it is limited in that it considers economic choices and consequences one field (well) and one year at a time. Three different departments (Agronomy-Horticulture, Agricultural Economics and Biological Systems Engineering) will combine their expertise to develop information to enhance Water Optimizer by: 1) improving the tool's function for crops grown in the semiarid High Plains, including canola, camelina, chickpeas, dry beans and sunflowers; 2) expanding the tool's geographic coverage area to additional counties in Nebraska including irrigated areas in Colorado and Kansas; 3) developing the capability to evaluate risk-management alternatives on a whole-farm basis as well as field by field; and 4) developing the capability to determine the best strategies for managing multi-year water allocations. The benefits of this project will be to maintain profitability and sustain farming enterprises with a limited irrigation supply. The goal is to conduct educational programming in conjunction with the project to encourage other producers to implement practices and concepts demonstrated in this project. An additional outcome will be transferring this information to other areas of declining ground water or surface water.

The Water Optimizer tool was developed to assist in addressing water shortages created by drought and interstate water rights litigation. The current model released November 2010, supports all 93 Nebraska counties.

Project Support U.S. Department of Agriculture Risk Management Agency
Project Website http://agecon.unl.edu/wateroptimizer
Report
Current Status Underway
Topic Crop Water Use
Project's Primary Contact Information
Name van Donk, Simon
Unit West Central Research and Extension Center
Email svandonk2@unl.edu
Phone 308-696-6709
Web Page http://westcentral.unl.edu/web/westcentral/svandonk
Project Information
Title Determining the effect of the amount and timing of irrigation on corn production, using subsurface drip irrigation (SDI)
Description

It is important to learn how to grow crops with limited amounts of water and to determine crop water use with SDI. In 2007 a field study with corn was initiated that will be continued in 2008 and 2009. The treatments are:

  • Rainfed (no irrigation)
  • 0.50 ET (meet 50% of evapotranspiration requirements) throughout the season
  • 0.75 ET throughout the season
  • 1.00 ET throughout the season
  • no irrigation at first, 1.00 ET during 2 weeks around tasseling, then no more irrigation after that
  • 0.50 ET at first, 1.00 ET during 2 weeks around tasseling, then 0.50 ET after that
  • 0.50 ET at first, 1.00 ET during 3 weeks around tasseling, then 0.50 ET after that
  • 0.50 ET at first, 1.00 ET during 4 weeks around tasseling, then 0.50 ET after that
  • 0.75 ET at first, 1.00 ET during 4 weeks around tasseling, then 0.75 ET after that

Using SDI may not only increase water use efficiency, but also nutrient use efficiency when applying nutrients through the SDI system. This study was conducted at WCREC to assess the effect of different in-season nitrogen (N) application (via SDI) timings on corn production and residual soil nitrate-nitrogen (NO3-N). We evaluated the effect of three N application timing methods at two N application rates (UNL recommended rate and the UNL rate minus 20%) on corn grain, biomass yield, and end-of-study distribution of residual soil NO3-N.

In 2006, there were no significant differences in corn grain yields between the two N application rates. In 2007, the grain yield under the UNL recommended N rate was significantly higher (3.0 bu/ac) than under the UNL-minus-20% N rate. In both years, grain yield and biomass production for the N application timing treatments were not significantly different. The lack of response to different N application timing treatments indicates that there is flexibility in N application timing for corn production under SDI. This two-year field study was published in Soil Science.

Impact: This study helps us better understand the most appropriate times to apply N with SDI (underground fertigation). If applied at inappropriate times, nitrates are not used by the crop and may leach into groundwater. If N use is minimized, the producer's cost can be minimized.

Project Support n/a
Project Website
Report SDI_Corn_Yield.pdf
Current Status Completed
Topic Drought
Project's Primary Contact Information
Name Knutson, Cody
Unit National Drought Mitigation Center
Email cknutson1@unl.edu
Phone 402-472-6718
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=430
Project Information
Title Republican River Basin Water and Drought Portal
Other(s) Mark Svoboda, NDMC, msvoboda2@unl.edu; Donna Woudenberg, NDMC, dwoudenberg2@unl.edu; Jae Ryu, jryu@uidaho.edu 
Description The National Drought Mitigation Center (NDMC) is developing a decision-support web portal for the Republican River Basin in Nebraska, Colorado and Kansas, with support from the managers and staff of the Lower, Middle and Upper Republican Natural Resources Districts (NRDs) in Nebraska. Under the terms of the two-year grant, the NDMC will collaborate with the NRDs to identify and compile local drought monitoring and planning information needed by resource managers in the basin, including government agencies, local community planners, and agricultural producers, and package it into a web portal. The portal will eventually be housed on the websites of the NRDs and can serve as a model for developing local applications of the National Integrated Drought Information System.
Project Support National Oceanic and Atmospheric Administration - Sectoral Applications Research Program
Project Website http://www.rrbdp.org
Report
Current Status Underway
Topic Extension
Project's Primary Contact Information
Name van Donk, Simon
Unit West Central Research and Extension Center
Email svandonk2@unl.edu
Phone 308-696-6709
Web Page http://westcentral.unl.edu/web/westcentral/svandonk
Project Information
Title West Central Research and Extension Center - Gudmundsen Sandhills Laboratory
Other(s) Jim Goeke, West Central Research and Extension Center, jgoeke1@unl.edu 
Description

The University of Nebraska West Central Research and Extension Center is a research and extension facility of the University of Nebraska Institute of Agriculture and Natural Resources (IANR). It serves as the site for field-based research and extension involving faculty and graduate students in eight IANR departments. West Central consists of approximately 1,800 acres of which 1,100 acres are in pasture with the remaining in dryland and irrigated cropping systems. West Central delivers research-based education and information to citizens throughout the state. Extension specialists and educators are committed to excellence, conducting educational programs customized to meet the needs of Nebraskans. These educational programs, delivered via a variety of methods, are offered through federal, state and county partnership arrangements and provide research-based information and other educational resources to the 20-county West Central district and beyond.

The Gudmundsen Sandhills Laboratory (GSL), a 13,000 acre working ranch in the Nebraska Sandhills, is also part of West Central. GSL is situated over a relatively small portion of the High Plains Aquifer where saturated thickness exceeds 1000 feet. GSL also features a valley with a live stream, a drained valley with wet meadows, an adjacent lake, dry valleys, and many dune types so that literally all the surface and groundwater locales in the Sandhills are represented and available for research. In 2004 a U.S. Climate Reference Network station was established at GSL to provide future long-term observations of temperature and precipitation accurate enough to detect present and future climate change.

Project Support Varies according to program and project - for more information see http://www.westcentral.unl.edu
Project Website http://westcentral.unl.edu/web/gudmundsen/
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 Hydraulics
Project's Primary Contact Information
Name Szilagyi, Joe
Unit School of Natural Resources
Email jszilagyi1@unl.edu
Phone 402-472-9667
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=119
Project Information
Title Identifying Cause of Declining Flows in the Republican River
Description

The Republican River, shared by three states, Colorado, Nebraska, and Kansas, has yielded depleted streamflow at the Nebraska-Kansas border for about 20 years when compared to values preceding 1970. Based on model results estimating the average annual water balance of the basin, it is concluded that the observed decline in runoff cannot be explained by changes in climatic variables over the area; rather, it is the result of the combined effects of the following human activities: crop irrigation, change in vegetative cover, water conservation practices, and construction of reservoirs and artificial ponds in the basin. These human-induced changes have one property in common: they all increase the amount of water being evaporated over the basin, thereby reducing the amount of water available to runoff.

More about this research in the Journal of Water Resources Planning and Management

Project Support UNL School of Natural Resources
Project Website n/a
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 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 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 Eisenhauer, Dean
Unit Biological Systems Engineering
Email deisenhauer1@unl.edu
Phone 402-472-1637
Web Page http://bse.unl.edu/eisenhauer1
Project Information
Title Impacts of Land Terracing and Small Ponds on Basin Water Supplies
Other(s) Jim Koelliker, Biological and Agricultural Engineering, Kansas State University, koellik@ksu.edu; Derrel Martin, Biological Systems Engineering, dmartin2@unl.edu; Phil Barnes, Biological and Agricultural Engineering, Kansas State University, lbarnes@ksu.edu; Ayse Kilic, School of Natural Resources, akilic@unl.edu 
Description

Terraces in the Republican River Basin total about 2 million acres; about 15% of the basin above Hardy, Nebraska is terraced. The goal of this project is to better understand how on-farm conservation practices, specifically terraces and small ponds, affect the basin's water supplies. Data has been collected at five dryland fields near Culbertson, Curtis, and Stamford, Nebraska and Colby and Norton, Kansas. The Kansas sites are in areas where three main tributaries of the Republican River - Beaver, Sappa, and Prairie Dog creeks - flow toward Harlan County Reservoir. The field data collected will be used to determine if computer models created for the Republican River Basin accurately measure the impact of conservation terraces and small reservoirs on the basin.

Initial research results show:

  • About 16% of land in the Republican Basin is protected by terraces, and an equal number by small reservoirs
  • About 45% of runoff into a terrace channel goes to evapotranspiration (ET), 45% goes to groundwater recharge, and 10% overtops the terraces
  • Small reservoirs retain about 90% of inflow, most of which goes to groundwater recharge - little evaporation
  • Much overland flow is loss in transmission as recharge or ET from plants in the creek

Integrated values for the basin be completed by the end of 2010. For more information, see the following slides presented at the 2010 Greater Platte Basins Symposium:

Project Support U.S. Bureau of Reclamation
Project Website http://watercenter.unl.edu/PRS/PRS2010/Presentations/Eisenhauer%20Dean.pdf
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 Woldt, Wayne
Unit Southeast Research and Extension Center
Email wwoldt1@unl.edu
Phone 402-472-8656
Web Page http://bse.unl.edu/wwoldt1
Project Information
Title Watershed Modeling System
Description Due to the highly connected nature of the water resources in the Republican River region, the significant increase in groundwater utilization for irrigation is suspected of inducing changes to the surface water system. These changes are exacerbated by drought conditions. Therefore, a greater understanding of the complex surface-groundwater system is very important for better management of water resources in the area. This project involves developing a watershed modeling system capable of simulating subsurface, overland, and stream flow in a fully integrated manner. This model considers various hydrogeological properties and therefore provides a more real picture of groundwater and surface water flow patterns and connections in the region. (This modeling system is different than traditional models such as ModFlow.) The objective of the research is to study the interaction processes of groundwater and surface water flow. The second objective is to progress toward simulating large-scale watersheds and significant amounts of data with increased time efficiency.
Project Support n/a
Project Website
Report
Current Status Underway
Topic Invasive Species
Project's Primary Contact Information
Name Allen, Craig
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 Monitoring, Mapping and Risk Assessment for Non-Indigenous Invasive Species in Nebraska
Other(s) Karie Decker, Nebraska Invasive Species Project Coordinator, invasives@unl.edu 
Description

Biological invasions are a growing threat to both human enterprise and ecological systems. This project provides resources to the public and private sector on: 1) the potential spread and impact of non-indigenous species in Nebraska; 2) actual and potential maps of non-indigenous species range (habitat specific maps at high resolution); 3) information regarding identification and management of potential invaders; 4) centralized information on management and impacts and potential spread of currently established non-indigenous species (a web portal); and 5) outreach within Nebraska to county-level governments and individual stakeholders regarding the management, surveillance and control of non-indigenous species. On February 7-8, 2008 a conference on non-indigenous species impacts, spread and management was held, focusing on state-of-our-knowledge and coordination of disparate management and information-provisioning efforts with a goal towards unification of disparate efforts.

This project is meant to build momentum towards a cohesive non-indigenous species biosecurity and management system in Nebraska that is integrated and relatively seamless across institutional boundaries. Spatially - based risk assessments that focus on non-indigenous invasive species impacts on at - risk native species and communities in Nebraska have been initiated with funding from the U.S. Geological Survey and the Nebraska Game and Parks Commission. The results and predictive models generated by this project will be delivered and made widely available to policy makers, management practitioners and landowners in Nebraska. Additional general information about potential invasive species and their impacts will be made easily accessible. Most of the goals listed above will produce and disseminate products that are dynamic, with interactive elements for the public and managers, including mapping of habitat-specific current and potential distributions of invasive species as well as a portal through which the public can inform the entities responsible for management of invasive species occurrence and spread - and vice versa.

Project Support U.S. Geological Survey, Nebraska Game and Parks Commission, Nebraska Environmental Trust
Project Website http://snr.unl.edu/invasives
Report
Current Status Continuing
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 Invasive Species
Project's Primary Contact Information
Name Huddle, Julie
Unit School of Natural Resources
Email jhuddle2@unl.edu
Phone 402-472-8556
Web Page http://snr.unl.edu/vitae/faculty/2011/huddle-julie-cv-11012010.pdf
Project Information
Title Effects of eastern redcedar on the hydrology of cottonwood stands in the Republican River Basin
Other(s) Tala Awada, School of Natural Resources, tawada2@unl.edu, Derrel Martin, Biological Systems Engineering, dmartin1@unl.edu, Xinhua Zhou, School of Natural Resources, xzhou3@kumc.edu, Sue Ellen Pegg, School of Natural Resources, spegg2@unl.edu, Scott Josiah, Nebraska Forest Service, sjosiah2@unl.edu 
Description

This study examines how much water trees use in different forests. In riparian forests, invasive plants affect the quantity of water infiltrating and running off land by intercepting water and transpiring water. Sap flow sensors are being used to monitor how removal of invasive tree species affects tree-level and stand-level evapotranspiration. In addition, vegetation transects will reveal how understory plants respond to invasive tree removal. Researchers are gathering data using eddy covariance towers and satellite images. Study results will be used to test whether removing eastern Red Cedar and Russian Olive Trees can significantly improve water yields.

In regards to the understory response following the removal of invasive woody species from a cottonwood riparian forest, this research shows that:

  • Removing invasive species increased the frequency of invasive form and warm season grasses.
  • Species diversity increased when invasive tree species were removed.
  • Changes in understory species following thinning were most pronounced where eastern redcedars were removed.
  • Light level differences observed under different canopy types likely explain differences in understory species response to thinning. This will be examined in future studies.
Project Support Burlington Northern Endowment, Nebraska Department of Natural Resources, Nebraska Natural Resources Districts in the Republican River Valley, Southwest Nebraska Resource Conservation and Development (RCandD) Council Inc., Nebraska Southwest Weed Management Area
Project Website
Report Photographs of Understory.pdf
Current Status Published in the Great Plains Research 2011 21: 49-71
Topic Pollution Prevention
Project's Primary Contact Information
Name Comfort, Steve
Unit School of Natural Resources
Email scomfort1@unl.edu
Phone 402-472-1502
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=21
Project Information
Title Using Slow-Release Permanganate Candles to Remove TCE From a Low Permeable Aquifer at a Former Landfill
Other(s) Mark Christenson, School of Natural Resources; Ann Kambhu, Department of Civil Engineering 
Description

Past disposal of industrial solvents into unregulated landfills is a significant source of groundwater contamination. In 2009, we began investigating a former unregulated landfill with known trichloroethene (TCE) contamination. Our objective was to pinpoint the location of the plume and treat the TCE using in situ chemical oxidation (ISCO).

While the characteristics of the low permeable aquifer at the Cozad site dictates that additional field monitoring will be needed for several years to fully determine the efficacy of the slow release candles, initial field results and the supporting laboratory results presented indicate that slow-release permanganate candles may be an effective means of treating chlorinated solvents in low permeable zones. Potential advantages to the candle technology are that they negate the need for specialized equipment (mixing trailer, pumps, hoses, etc.), curtail health and safety issues associated with handling liquid oxidants, and when used in a barrier design, could potentially provide a long-term solution for controlling contaminant migration.

Project Support United States Environmental Protection Agency, University of Nebraska School of Natural Resources and Water Science Laboratory
Project Website n/a
Report Comfort_TCE.pdf
Current Status Completed
Topic Production Agriculture
Project's Primary Contact Information
Name Supalla, Raymond
Unit Agricultural Economics
Email rsupalla1@unl.edu
Phone 402-472-1792
Web Page http://agecon.unl.edu/supalla
Project Information
Title Economic and State Budget Cost of Reducing the Consumptive Use of Irrigation Water in the Platte and the Republican Basins
Other(s) Brian McMullen, Agricultural Economics, bmcmullen2@unl.edu 
Description

The terms of the Cooperative Agreement for the Platte Basin and the Supreme Court settlement decision for the Republican Basin both require that Nebraska reduce its consumptive use of irrigation water. This analysis evaluated the economic and the budgetary costs of meeting these requirements. Both the on-farm and off-farm costs were evaluated for both land retirement and water allocation programs, implemented in several different ways, over three alternative time periods, 10, 25 and 50 years.

The on-farm economic costs were defined as the change in net farm income associated with less irrigation. Off-farm economic costs were defined as the statewide change in household income resulting from changes in irrigation, as the effects ripple through the Nebraska economy. Budgetary costs were defined as the cost to the state budget (taxpayers) of policies which compensate irrigators for reducing consumptive use are implemented. Statewide economic costs were found to be lower for land retirement than for allocation programs, assuming the same total change in consumptive use. Total budgetary costs depended primarily on: where the irrigation reductions occurred (proximity to river); on how long the program was continued (number of years), and on whether irrigation was reduced voluntarily with incentives, or by regulation, or by some combination of regulation and incentives. It was found that policy makers could minimize the cost of reducing consumptive use from irrigation and augmenting stream flow by purchasing rather than leasing irrigation rights, by using a regulatory rather than a willing seller incentive approach, and by reducing irrigation at locations close to the river.

More on this research in a UNL Agricultural Economics working paper

Project Support n/a
Project Website
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 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 Riparian Vegetation Impacts on Water Quantity, Quality, and Stream Ecology
Other(s) Kyle Herrman, University of Wisconsin - Stevens Point, Kyle.Herrman@uwsp.edu; 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

The State of Nebraska is attempting to aggressively manage invasive species along the riparian corridors of the Platte River and the Republican River. Although the impetus for the removal is different, in both basins state agencies and weed management districts are using herbicides and mechanical removal to control a combination of invasive species led by Phragmites australis (common reed), Tamarix ramosissima Ledeb. (saltcedar), and Elaeagnus angustifolia L. (Russian olive).

Along the central stretch of the Platte River, invasive species have overtaken sandbars and side channels which are invaluable wildlife habitat. In an attempt to reclaim this habitat for bird species such as the Piping Plover and Whooping Crane, the state is removing large stretches of common reed. Along the Republican River, the state is removing all invasive species to reduce riparian evapotranspiration. By reducing evapotranspiration the hope is to increase stream flow along the Republican River. Since 2007 invasive species along the mainstem of the river and along the banks of the Harlan Reservoir have been sprayed with herbicide or mechanically removed.

In order to understand the impacts of removing invasive species along riparian corridors researchers at the University of Nebraska-Lincoln and collaborators at other universities have developed a multi-faceted research project.

On the Republican River basin researchers are directly measuring evapotranspiration rates from native and invasive plants. Researchers are also using a regional water balance model to estimate the water savings that could be achieved by removing all invasive species within the basin.

On the Platte River researchers are monitoring water quality changes associated with a controlled herbicide treatment of common reed. Using a combination of in situ instruments and grab samplers researchers are determining the impacts of species removal. Other experiments are being conducted to measure how invasive species alter biogeochemical processes and sediment characterization.

Visit the project website for more information, including real-time meteorological data from a riparian wetland near the Republican River, real-time water quality data at a stream site on the Platte River, and quarterly project reports.

Project Support Nebraska Environmental Trust, University of Nebraska Rural Initiative, University of Nebraska Institute of Agriculture and Natural Resources
Project Website http://www.geosciences.unl.edu/riparian/
Report
Current Status

Final Report on Riparian Vegetation Impacts on Water Quantity, Quality, and Stream Ecology

Topic Riparian Vegetation Water Use
Project's Primary Contact Information
Name Martin, Derrel
Unit Biological Systems Engineering
Email dmartin2@unl.edu
Phone 402-472-1586
Web Page http://bse.unl.edu/faculty/Martin.shtml
Project Information
Title Estimation of Evapotranspiration from Riparian and Invasive Species Using Remote Sensing and in Situ Measurements in the Republican River Basin
Other(s) Ayse Kilic, School of Natural Resources, akilic@unl.edu; Suat Irmak, Biological Systems Engineering, sirmak2@unl.edu; Shashi Verma, School of Natural Resources, sverma1@unl.edu; Tala Awada, School of Natural Resources, tawada2@unl.edu 
Description

This study is using a combination of techniques including remote sensing, to develop reliable estimates of evapotranspiration from riparian zones and determine varying water use rates for typical and invasive species in the Republican River Basin. The project will provide datasets of evapotranspiration and the annual water balance for a range of conditions in the riparian areas along the Republican River. Specific deliverables of the project include:

  • Map of surface energy fluxes, including evapotranspiration, across three watersheds in the Lower, Middle and Upper Republican Natural Resources Districts for different spatial and temporal (i.e. daily, seasonal and annual) scales.
  • Map of riparian vegetation classification across three watersheds using high resolution remote-sensing and ground truth observations.
  • Comparison of water use and water availability on riparian vegetation and adjacent treated research area by measuring evapotranspiration rates, using various methods.
  • Data for planners and decision-makers to develop water management policies.
  • Extension and education materials to inform and communicate results to stakeholders.
Project Support Nebraska Department of Natural Resources
Project Website
Report
Current Status Underway
Topic Water Quality
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 Distribution Patterns of Nitrate-Nitrogen in Groundwater
Other(s) Fujiang Wen, Doctoral Candidate in the School of Natural Resources, fwen314@yahoo.com 
Description

This paper evaluated spatial patterns of nitrate-nitrogen contamination of groundwater in the High Plains Aquifer in the area of Dawson, Buffalo and Hall counties in the South-Central Platte River Valley of Nebraska. Geostatistical approaches including ordinary kriging, indicator kriging and cokriging, were used to analyze 1514 samples drawn from 465 irrigation wells over a 30-year period. The spatial trends of the nitrate-N concentration suggested that about one third of the aquifer in the area had been contaminated by nitrate-N above a level of 5 ppm.

The small areas along with the South-Central Platte River Valley were classified as high risk with the nitrate-N level above 10 ppm. The probabilistic maps exceeding thresholds (10 and 5 ppm) for the nitrate-N concentrations of the groundwater were created to assess vulnerability. The areas with the nitrate-N levels exceeding 10 ppm at an extremely high risk (>75%) were delineated for the future nitrate priority areas of management. Temporal trends of the nitrate-N contamination at 465 sampling locations were analyzed for a period of 30 years. Thirty-seven (37) sampling wells, accounting for 8.0% of the total sampling wells, were identified with an increasing trend, in which the maximum increase was estimated at 4.20 ppm per five-year. Twenty-nine (29) wells were identified with a decreasing trend, in which the average decrease was 0.48 ppm per five-year. It was concluded that the groundwater nitrate-N contamination in some areas, such as the middle area of Buffalo County, was improving, but was worsening in other areas, such as the middle portion of Hall County and the south-eastern corner of Buffalo County. It was found that groundwater irrigation level (or well density) has a positive correlation with high concentration of nitrate-N.

Project Support Central Platte Natural Resources District
Project Website
Report
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 Water Quality
Project's Primary Contact Information
Name van Donk, Simon
Unit West Central Research and Extension Center
Email svandonk2@unl.edu
Phone 308-696-6709
Web Page http://westcentral.unl.edu/web/westcentral/svandonk
Project Information
Title Quantify the extent of vertical hormone movement through vadose zone soils
Description

The extent of exogenous hormone use in beef cattle production, in addition to endogenous hormones, increases the risk of hormone residues entering the environment when manure is applied to soil. This research will provide key information on the environmental fate of hormones commonly found in feedlot cattle manure. This information is critical in developing management practices for concentrated animal feeding operations and farms that will reduce environmental risks associated with land application of manure.

This research will be conducted using the specialized percolation lysimeters research site at the West Central Research and Extension Center during 2008 and 2009. The site contains fourteen percolation lysimeters installed at the center of each of fourteen field plots. Each plot is 40 ft m by 40 ft. Each lysimeter contains an undisturbed soil core with a diameter of 3 ft and a depth of 8 ft and has porous extractors at the bottom, which allows the extraction of leachate from unsaturated soil using a vacuum pump. These lysimeters have been used successfully for several nitrate-leaching experiments. Water samples, which represent the water that is leached from the crop root zone, can be collected at the bottom of these lysimeters and will be used to determine the amounts and types of hormones leaching below the crop root zone. Treatments will consist of treated stockpiled manure, treated compost manure, and a check (no manure application). The manures will be applied to the lysimeters and field areas adjacent to the lysimeters in the spring of 2008 at application rates to satisfy the nitrogen needs of corn based on University of Nebraska recommendations. The check plots will receive commercial nitrogen fertilizer to match the manure N availability. Three treatments and three replications (nine lysimeters in nine plots) will be used for this study.

Wheat will be planted in the lysimeters and adjacent plots during both years. Soil moisture from each plot will be measured weekly at 1 ft depth increments to a depth of 7 ft, using the neutron probe method. Water samples will be collected every three weeks from the lysimeters from April to November in both years. Soil samples will be collected at six depth increments down to a depth of 8 ft, four times between application and October in 2008, and three times from April to August in 2009. To reduce sampling errors created by spatial variability within each plot, five sub-samples will be taken from each depth. The sub-samples will then be mixed to create one composite sample. Background soil profile samples will be taken before the manure is applied. Sampling depths will be increased as needed, based on the confirmed movement of hormones of interest through the soil profile. Soil and leachate samples will only be taken during the periods when the ground is not frozen (April to November), when movement of water is expected.

Project Support n/a
Project Website
Report
Current Status Continuing
Topic Watershed Management
Project's Primary Contact Information
Name Allen, John C.
Unit Agricultural Economics
Email jallen1@unl.edu
Phone 435-797-9732
Web Page
Project Information
Title Socio-Cultural Study of the Middle Platte River Region of Nebraska: Building Capacity for Community-Based Conservation
Description Telephone surveys, focus group interviews, and in-depth interviews were conducted in 1997 and community profiles developed in 1998 to provide an integrated picture of the social and cultural factors that influence how Middle Platte River residents and communities perceive the river; where their futures fit with the perceived best case scenarios; and the future they see for themselves, their family, and their community.
Project Support U.S. Environmental Protection Agency
Project Website http://watercenter.unl.edu/PRS/PlatteRiverReports/Socio-Cultural%20Study%20of%20the%20Middle%20Platte%20River.pdf
Report
Current Status Completed
Topic Watershed Management
Project's Primary Contact Information
Name Hoagland, Kyle
Unit Nebraska Cooperative Fish and Wildlife Research Unit
Email khoagland1@unl.edu
Phone 402-472-9544
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=50
Project Information
Title Making Adaptive Management Meaningful: Translating Science Learning into Policy Decision-Making
Other(s) Chad Smith, School of Natural Resources, smithc@headwaterscorp.com 
Description

Adaptive management has been and continues to be implemented around the country and world, yet few examples exist of programs successfully implementing all six steps (Assess, Design, Implement, Monitor, Evaluate, and Adjust) of adaptive management. A key break point in this process seems to be synthesizing collected data and using that synthesis to tell a story about what data say in regard to key questions and hypotheses in a way that is useful to decision-makers and results in positive changes in management or policy.

Chad Smith continues his research into the gap between science and decision-making in adaptive management programs and tools to successfully bridge that gap.

GOALS:

  1. Explore the science and policy interface in a comparative study of several adaptive management programs
  2. Provide specific background on this issue as it relates to the Platte River Recovery Implementation Program
  3. Showcase decision analysis and other tools that can be used as decision support in the Platte River and other adaptive management programs
  4. Discuss opportunities for and challenges to bridging the science/policy gap

Smith is applying learning from his research in the real world, serving as Adaptive Management Plan implementation coordinator for the Platte River Recovery Implementation Program. He is also co-lead of a small team writing an Adaptive Management Plan for the Middle Rio Grande Endangered Species Collaborative Program.

Project Support n/a
Project Website http://snr.unl.edu/necoopunit/research.main.html#making_adaptive_management
Report
Current Status Continuing
Topic Watershed Management
Project's Primary Contact Information
Name Knutson, Cody (advisor)
Unit National Drought Mitigation Center
Email cknutson1@unl.edu
Phone 402-472-6718
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=430
Project Information
Title Stakeholder Perceptions of Water Supply Management and Sustainability in the Republican River Basin in Nebraska
Other(s) Ryan Bjerke, ryan.bjerke@huskers.unl.edu 
Description Due to a variety of human-induced and natural factors, water resources throughout the world will continue to face mounting challenges to their longevity and extent, and those within the Republican River Basin in Nebraska are no exception. Understanding the perspectives of water users is essential for developing informed and effective water resource policies and management plans. This study utilized a key informant sampling strategy in conjunction with in-depth telephone interviews to ascertain the perceptions of 32 key stakeholders in the Republican River Basin in Nebraska on concepts pertaining to water supply management and sustainability. The interview questionnaire was designed using a mixed methods approach that relied on qualitative and quantitative measures. Specifically, stakeholders were asked a series of questions to understand their perspectives on: the causes of water supply stress in the basin; what sustainable water management meant to them; the sustainability of water resources in the basin; and solutions that could be implemented to reduce water supply stress in the basin (e.g., financial, regulatory, infrastructure development, and water conservation and technical options). The study found a majority of individuals attributed ground water level declines to increased ground water use, more ground water users, and changing climate, while most believed surface water flow reductions were due to these factors in addition to soil and water conservation measures and increased near- and in-channel plant growth. Because of the need to maintain economic viability and protect water for future generations, water resource sustainability was very important to participants. Stakeholders thought solutions to water resources issues could be best achieved by employing a combination of: regulatory measures, like irrigated acreage and pumping limits; water conservation options, such as crop rotations and conservation tillage; and technological advancements, like more water-efficient irrigation systems and improved hybrids. Overall, eliciting stakeholder's perceptions on issues related to water supply stress and sustainability, along with potential solutions, may help inform policy and management decisions aimed at promoting water resource sustainability in the basin.
Project Support
Project Website
Report
Current Status Graduate thesis project completed December 2009 - thesis available at UNL CY Thompson Library (Call # LD3656 2009 .B547)
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 Allen, Craig
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 River Otter Home Range and Habitat Use
Other(s) Sam Wilson, School of Natural Resources, swilson5@yahoo.com; Amy Williams, School of Natural Resources, amy_ruth18@hotmail.com 
Description

River otters (Lontra canadensis) are native to Nebraska but were extirpated by the early 1900s. River otters became reestablished in Nebraska following their reintroduction in the mid 1980s and early 1990s by the Nebraska Game and Parks Commission. The species is currently listed as threatened in Nebraska. Despite the high profile of the reintroduction and the otters' role as a flagship species, relatively little is known about river otter ecology in Nebraska. In order to provide information for management, research was conducted to determine home range, habitat use, overnight movement distance, and annual survival of river otters in the central Platte River of Nebraska.

Eighteen river otters were trapped, implanted with telemetry transmitters, and tracked during 2006-2009. Researchers obtained 996 telemetry locations and constructed 13 annual home ranges. Male home ranges were larger than female home ranges. Habitat use was determined by comparing used versus available habitats using compositional analysis. Open water was used more than any other habitat type in all three comparisons tested.

Nineteen overnight movements were recorded (465 total telemetry locations) for four river otters during 2007-2008. Movements during January-February, when NGPC conducts winter bridge surveys, were lower than during the rest of the year. Annual survival was 100% as no river otter mortalities were detected during the study period.

River otters in the central Platte River select open water over other habitat types, exhibit reduced movements during winter months, and have high annual survival. This information will be used by NGPC to assess the status of river otters in Nebraska and direct management efforts for the species.

Project Support Nebraska Game and Parks Commission
Project Website n/a
Report Wilson River Otter.pdf
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 Pope, Kevin
Unit Nebraska Cooperative Fish and Wildlife Research Unit
Email kpope2@unl.edu
Phone 402-472-7028
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=759
Project Information
Title Population Assessment of Channel Catfish in Nebraska
Other(s) Lindsey Chizinski, Graduate Assistant 
Description

Channel catfish (Ictalurus punctatus) is an important sport fish, particularly in the Great Plains. In Nebraska, a majority of anglers target channel catfish, and fishing activities are a vital part of the state’s economy. Lentic water bodies provide the primary fishing opportunity for catfish anglers in Nebraska. Despite the popularity and economic importance of channel catfish, little is known of its population dynamics or habitat requirements, and existing studies often profile river populations.

Current standards for sampling channel catfish in lentic systems often yield inadequate catch to assess populations. The objective of this study was to utilize a recently developed sampling method, tandem-set hoop nets, to collect channel catfish in sufficient quantities to describe the effects of stocking and habitat variability on populations in lentic ecosystems. Three lentic ecosystems common to the Great Plains were considered: sand pits, flood-control reservoirs, and irrigation/power-generation reservoirs.

The influence of stocking on abundance and condition of channel catfish varied with ecosystem type. In sand pits, stocking negatively influenced fish condition, and only stocking on an annual basis positively influenced abundance. In flood-control reservoirs, stocking did not influence fish condition, but was associated with greater abundance. In irrigation/power-generation reservoirs, stocking did not influence fish condition or abundance. Additionally, there was evidence that mortality and growth rates varied with ecosystem type. In general, channel catfish from irrigation/power-generation reservoirs were predicted to experience slower growth and lower mortality, whereas channel catfish from sand pits were predicted to experience the fastest growth and highest mortality.

Catch rates of channel catfish were substantially less in this study compared to previous records of tandem-set hoop net surveys, but hoop nets were more efficient than the current standard gear, experimental gill nets, at capturing channel catfish. That is, 100 channel catfish could be captured with fewer sets of hoop nets than gill nets. However, catch rates and size structure of channel catfish in tandem-set hoop nets varied within the sampling season and between years. Furthermore, length-frequency distributions of channel catfish were dissimilar between hoop nets and gill nets.

Click here to read Lindsey Chizinski's Master's Thesis on Channel Catfish Population in Nebraska

Project Support Nebraska Game and Parks Commission
Project Website http://snr.unl.edu/necoopunit/research.main.html#channel_catfish
Report
Current Status Completed
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