NU Water-Related Research in District 38

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 41 records found for District 38


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 Bernards, Mark
Unit Agronomy and Horticulture
Email mbernards2@unl.edu
Phone 402-472-1534
Web Page http://agronomy.unl.edu/bernards
Project Information
Title Water Use of Winter Annual Weeds
Other(s) Suat Irmak, Biological Systems Engineering, sirmak2@unl.edu 
Description

This study examines the water use of winter annual weeds. More winter annual weeds grow now than 20 years ago because of the adoption of reduced tillage systems, where the soil is not disturbed between harvest and planting. Winter annuals typically germinate in the fall, overwinter as small plants, and grow rapidly as temperatures warm in the spring; these weeds are especially well adapted to limited summer rainfall. Common winter annuals in Nebraska are downy brome, henbit, field pennycress, wild mustard, marestail (horseweed), foxtail barley, shepherdspurse, speedwell, and prickly lettuce. This project is investigating whether allowing winter annual weeds to grow too long in the spring depletes the soil of moisture that would benefit the crop later in the summer.

Estimated potential nitrogen immobilization by winter annual weeds may be calculated as:

  • 500 lbs/ac of winter annual biomass growth at planting time (this would be a relatively dense, uniform stand of weeds).
  • As a general statement, nitrogen composes approximately 3% of plant biomass.
  • $0.58/lb of nitrogen fertilizer (based on $950/ton of anhydrous ammonia)

Based on these assumptions, a dense, uniform stand of winter annuals could tie up approximately 15 lb of nitrogen per acre (500 x 0.03), or $8.70 per acre (15 x 0.58) of nitrogen intended for a corn crop.

Estimating the irrigation cost to replace water used by the same 500 lbs/A of winter annual biomass by assuming:

  • 500 lbs/A of winter annual weed biomass at planting time,
  • 800 lbs of water is required to produce 1 lb of winter annual weed biomass.
  • At $2.50 diesel fuel, applying 1 inch of irrigation water per acre would cost $9.66.

The 500 lbs of winter annual biomass would use 400,000 lbs of water per acre (500 x 800), or 47,920 gallons of water (400,000 lb x 0.1198 gal/lb). This equals 1.75 acre inches of soil water (47,920 gal /{27,158 gal/acre in}) used by these weeds. Based on a cost of $9.66 to apply 1 inch of irrigation water, it would cost approximately $17.00 per acre to replenish the water used by winter annual weeds in this scenario.

Project Support n/a
Project Website http://weedscience.unl.edu/
Report
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 Cassman, Ken
Unit Nebraska Center for Energy Sciences Research
Email kcassman1@unl.edu
Phone 402-472-5554
Web Page http://agronomy.unl.edu/cassman
Project Information
Title Crop Water Productivity Project
Other(s) Patricio Grassini, Agronomy and Horticulture, 
Description

This project will first establish benchmarks for irrigated corn within the Tri-Basin Natural Resources District and more broadly for the state and the High Plains. On-farm data from the Tri-Basin area will be compared with the benchmarks to estimate gaps between actual yields and optimum yields attainable with efficient water use. The goal is to adjust crop management to get greater yields with the same or a lesser amount of irrigation water. A 10% savings in irrigation water could total 90,000 acre feet and reduce annual pumping costs in Nebraska by $4 million. Farmers contributing to yield gaps will be identified in the project's first year; management advice and tools to help farmers improve yields and water productivity will be the focus of the second year.

Project Support Water, Energy and Agriculture Initiative - Nebraska Corn Board, Nebraska Soybean Board, UNL Agricultural Research Division, Nebraska Public Power District through the UNL Nebraska Center for Energy Sciences Research
Project Website
Report Grassini_Corn_Efficiency.pdf
Current Status Completed
Topic Crop Water Use
Project's Primary Contact Information
Name Hubbard, Kenneth
Unit High Plains Regional Climate Center
Email khubbard1@unl.edu
Phone 402-472-8294
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=55
Project Information
Title Data for Estimating Crop Water Use
Other(s) Ayse Kilic, School of Natural Resources, akilic@unl.edu 
Description

The University's High Plains Regional Climate Center (HPRCC) operates automated weather monitoring stations that take the essential information for calculating the Penman and Penman-Montieth reference evapotranspiration estimates. The estimates serve as the basis for estimating crop water use and as such are an essential element of the water budget for the hydrological cycle. These stations also monitor the soil moisture at four levels (10, 25, 50, and 100 cms) in the soil profile. The HPRCC is collecting hourly data from stations in Clay Center, Curtis, Holdrege, Imperial, McCook, Red Cloud, and Smithfield.

Project Support National Climatic Data Center
Project Website http://hprcc.unl.edu
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 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 Crop Water Use and Water Use Efficiency
Project's Primary Contact Information
Name Abunyewa, Akwasi
Unit Agronomy and Horticulture
Email akwasi_abunyewa@yahoo.com
Phone
Web Page
Project Information
Title Skip-Row and Plant Population Effects on Sorghum Grain Yield
Other(s) Richard Ferguson, Agronomy and Horticulture, rferguson@unl.edu; Charles Wortmann. Agronomy and Horticulture, cwortmann2@unl.edu; Drew Lyon, Panhandle Research and Extension Center, dlyon1@unl.edu; Stephen Mason, Agronomy and Horticulture, smason1@unl.edu; Robert Klein, West Central Research and Extension Center, rklein1@unl.edu 
Description This research conducted in Clay, Gosper, Frontier, Hayes, Center, Lincoln, Red Willow, and Cheyenne Counties from 2005 to 2007 evaluated the effect of skip-row configuration and planting population on sorghum grain yield and yield stability in nonirrigated, no-till fields. Results were not consistent or significant across the sites. Skip-row planting is expected to produce higher yields when growing season water is less than 26-27 inches, with conventional planting producing higher yields in wetter areas.
Project Support U.S. Agency for International Development to the International Sorghum and Millet Collaborative Research Support Program, Scholarship Secretariat, Government of Republic of Ghana
Project Website
Report Wortmann_Sorghum.pdf
Current Status Published Agron.J. 2010 102:296-302
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 Economics
Project's Primary Contact Information
Name Thompson, Christopher
Unit Agricultural Economics
Email cthompson2@unl.edu
Phone 402-472-8602
Web Page http://wateroptimizer.unl.edu
Project Information
Title Water Trading Can Reduce the Cost and Increase the Effectiveness of Groundwater Allocation
Other(s) Raymond Supalla, Agricultural Economics, rsupalla1@unl.edu 
Description This project determined that capping the total amount of water pumped with an allocation, and then permitting allocating rights to be traded, reduces control costs because water can move to where it is most valuable. Irrigators with inefficient irrigation systems or relatively unproductive land sell all or part of their allocation rights to irrigators with more productive operations at a mutually agreed upon price that makes both parties better off with no change in total pumping. Subsequent work suggests that cap and trade markets may be able to increase the effectiveness of a groundwater allocation program as well as reduce costs. Read more about this research in Cornhusker Economics
Project Support U.S. Department of Agriculture Risk Management Agency
Project Website http://wateroptimizer.unl.edu
Report Thompson_Water_Trading.pdf
Current Status Completed
Topic Extension
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 South Central Agricultural Laboratory - Crop Water Use Research
Description

The South Central Agricultural Laboratory is a University of Nebraska research farm located about 15 miles east of Hastings immediately south of Highway 6. The primary focus of this farm is the development and refinement of irrigated crop production practices for Nebraska agriculture and beyond. A number of research projects are currently underway on site and in conjunction with producers in the region.

  1. Crop water use efficiency, nitrogen use efficiency, and best irrigation and fertigation management practices for subsurface-irrigated corn and soybeans.
  2. Measurement of soil evaporation under no-till, conventional (disk) till, and ridge till practices for corn using frequency-domain reflectometers under three irrigation frequencies and five irrigation levels for corn.
  3. Development of best deficit irrigation management strategies for soybeans.
  4. Center pivot irrigation engineering and evapotranspiration research: measurement of crop coefficients, evapotranspiration, and yield of corn under deficit irrigation settings.
  5. Measurement of crop water use and crop water use efficiency of eight corn hybrids under full and deficit irrigation and dryland settings.
  6. Measurement of maximum allowable crop water stress that can be imposed on corn, stress versus crop growth-yield- and available soil water relationships.
  7. Crop canopy temperature measurements to quantify crop water stress index for corn and soybeans.
  8. Measurements of hydraulics and uniformity coefficients, crop water use efficiency of a new low pressure irrigation system for soybeans.
  9. Measurement of energy fluxes and crop coefficients using high frequency techniques such as Bowen ratio energy balance system and Eddy covariance system to provide improved evapotranspiration data for corn, soybeans, and natural grassland.
  10. Measurement of non-growing (dormant season) evaporative losses to quantify annual evaporation and other water balance components.
  11. Operational characteristics of atmometers (ETgage) to measure reference evapotranspiration and Watermark granular matrix sensors to monitor soil water status and their practical applications and demonstrations for effective irrigation management.
  12. Rootworm pressure effect on crop water uptake under center pivot irrigation.
  13. On-farm demonstration of limited irrigation strategies for making maximum use of water resources. The project is being conducted in partnership with the NRCS and Nebraska Corn Board in Hordville, Geneva, York, Edgar, Ord, West Point, Schuyler, and Mead in grower fields.
Project Support Varies according to program and project
Project Website http://scal.unl.edu/
Report
Current Status Continuous
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 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 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 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 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 Franklin County
Description

Dr. Chen conducted a pumping test in the alluvial aquifer near Bloomington and streambed tests in the Republican River channel. This data was used to develop a groundwater flow model in Franklin County to simulate the impact of groundwater pumping on stream flow.

Project Support n/a
Project Website
Report
Current Status Completed
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 Harvey, F. Edwin
Unit School of Natural Resources
Email feharvey1@unl.edu
Phone 402-472-8237
Web Page http://eas.unl.edu/people/faculty_page.php?lastname=Harvey&firstname=Ed&type=ADJ
Project Information
Title Hydrologic Research in the Rainwater Basin Wetlands of South-Central Nebraska
Description

As part of this project, Harvey and his students are conducting research to unravel the hydrology of central Nebraska's Rainwater Basin wetlands. These wetlands are of international importance as habitat for millions of migratory water birds. In addition, these playa wetlands may contribute to groundwater recharge and water quality improvement. However, many of the wetlands have been drained, and those remaining suffer functional impairment due to sedimentation and pesticide and fertilizer runoff.

Most of the remaining Rainwater Basin wetlands are geographically isolated. Currently research is underway to investigate the role of these wetlands in providing groundwater recharge and water quality improvement. This is a significant environmental issue of concern because groundwater in this region is of vital importance, providing drinking and irrigation water. Moreover, groundwater levels are declining throughout much of the region. Levels of nitrate and atrazine exceed drinking water standards in some parts of the basin. Most of the remaining playa wetlands are impaired by sediment and there is an active program to restore the wetlands by removing this sediment. Study sites are located in Phelps, Kearney, Clay, Fillmore, and York counties (see map below).

Three components need to be measured when establishing a hydrologic budget for these closed basin wetlands which are surface storage, evapotranspiration (ET), and groundwater recharge. ET is calculated by the Bowen-Ratio Energy Budget (BREB) Method with the aid of a Bower Tower. Surface storage and recharge data will be aided by stilling wells and drive-point wells, respectively. Hydroperiods and plant community diversity are being determined before and after sediment removal to evaluate the impact of in-washed sediments on recharge and underlying groundwater quality. Chloride concentrations obtained from upland runoff collectors will be incorporated into the Chloride Mass-Balance Method along with precipitation and sediment chloride concentrations to obtain recharge fluxes for a wetland site.

Two Master's theses and one Bachelor's thesis have been completed as part of this project:

  • Wilson, Richard D. (2010), Evaluating Hydroperiod Response in the Rainwater Basin Wetlands of South-Central Nebraska, MS Thesis, UNL School of Natural Resources, 163 p.
  • Foster, Sarah E., (2010), Temporal and Spatial Variations of Ions, Isotopes and Agricultural Contaminants in Surface Waters and Groundwater of Nebraska’s Rainwater Basin Wetland Region, MS Thesis, UNL Department of Earth and Atmospheric Sciences, 185 p.
Project Support U.S. Environmental Protection Agency
Project Website http://snr.unl.edu/harvey/projectrainwater.htm
Report
Current Status Continuing
Pic 1 Project Image
Pic Caption 1 The Rainwater Basin area of Nebraska. 
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 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 Invasive Species
Project's Primary Contact Information
Name Narumalani, Sunil
Unit School of Natural Resources
Email snarumalani1@unl.edu
Phone 402-472-9842
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=85
Project Information
Title Predicting Potential Occurrence and Spread of Invasive Plant Species along the North Platte River, Nebraska
Other(s) Justin D. Hoffman; Deepak R. Mishra, University of New Orleans, dmishra@uno.edu; Paul Merani; Robert G. Wilson, Panhandle Research and Extension Center, rwilson1@unl.edu 
Description

Riparian habitats are important components of an ecosystem; however, their hydrology combined with anthropogenic effects facilitates the establishment and spread of invasive plant species. Researchers used a maximum-entropy predictive habitat model, MAXENT, to predict the distributions of five invasive plant species (Canada thistle, musk thistle, Russian olive, phragmites, and saltcedar) along the North Platte River in Nebraska. Projections for each species were highly accurate. Researchers studied a 1-mile wide buffer on either side of the North Platte River channel from the Wyoming-Nebraska state line to approximately 3.2 km west of North Platte. Field work was conducted in September 2005, March 2006, and May 2007.

Researchers found different distribution patterns among the species. Russian olive and thistles closely resembled each other in extent and variable contribution. While conducting field work, researchers repeatedly documented thistles below Russian olives or in close proximity. In addition, both species were commonly documented at varying distances from the river. Conversely, researchers found phragmites and saltcedar to have a more restricted potential distribution. Saltcedar was common throughout most of the study area except in the extreme eastern parts. The eastern edge of the study area approaches the distribution limit of saltcedar in Nebraska (Kaul et al. 2006; Wilson and Knezevic 2006). Phragmites was common in the eastern parts of the study area; however, there was low to no probability of phragmites occurrence in the west. Potential suitable habitat diminished just west of Lake MaConaughy, suggesting researchers have identified the western distributional limit of phragmites on the North Platte River and in Nebraska.

Variable contribution among all species was similar, with elevation and distance from river as the two most important variables for all species. The most probable underlying variable explaining the significance of distance from river is soil moisture. In most cases soil moisture will decrease as distance from river increases. Although soil moisture may be more directly responsible for the observed plant distributions, this variable is not easily estimated over large areas, unlike distance from river. There was a large disparity of elevation in the study area. The importance of elevation may be the result of the locations of the survey sites, underlying mechanistic variables, or both. Collection sites occurred at the elevational extremes. For Russian olive, thistle, and saltcedar, the lack of presence data at median elevations most likely caused MAXENT to weight that variable higher than others. The predictive model of phragmites also determined elevation to be the most important variable. Unlike the other species, no phragmites was documented at the western site. It is possible that phragmites can not survive at higher elevations because of colder temperatures found at these sites. However, Saltonstall (2002) found invasive haplotypes of phragmites occurring at high elevations in Wyoming and Utah, which does not support the previous hypothesis. A more likely explanation is that phragmities is in the process of expanding its range westward on the North Platte River and has not had enough time to disperse to the western parts of the river.

The results of this study have management implications for these species along the North Platte River, as well as other river ecosystems. For example, the variables used in this study resulted in excellent predictions of the distributions of invasive plants. As mentioned above, some of these variables (i.e., elevation and distance from river) may have underlying mechanistic factors that are more accurate measures of plant distributions. However, one of the utilities of the current approach is that these variables are easy to access and generate in a geographic information systems environment and useful predictions can be derived, which is not the case for some of their potential underlying factors. Also, predictive modeling shows limited areas of suitable habitat in the western parts of the North Platte River, primarily along the river channel. Researchers suggest that extensive monitoring be conducted in these areas to identify any populations that may occur there. Identification and control of these populations will significantly slow or stop the westward spread of phragmites. Also, any populations of phragmites that occur in the west should be relatively small and isolated making control of these populations more feasible. Similarly, abundances of saltcedar decreased in the eastern parts of the North Platte River. As with phragmites in the west, a control strategy should be used for saltcedar while populations are small and manageable. In addition, both species were found to occur close to the river bed, thus by monitoring the riverbanks and sandbars, the majority of populations could be identified within a very limited search area. Russian olive and thistles occur throughout the study area. Researchers suggest that control of these species should take place in areas with high probability of occurrence to prevent establishment of monotypic stands of each species.

Project Support U.S. Department of Agriculture - Animal and Plant Health Inspection Service
Project Website
Report Narumalani_Invasive.pdf
Current Status Published in Invasive Plant Science and Management 2008 1:359-367
Topic Invasive Species
Project's Primary Contact Information
Name Narumalani, Sunil
Unit School of Natural Resources
Email snarumalani1@unl.edu
Phone 402-472-9842
Web Page http://snr.unl.edu/aboutus/who/people/faculty-member.asp?pid=85
Project Information
Title Detecting and Mapping Four Invasive Species along the Floodplain of North Platte River, Nebraska
Other(s) Deepak R. Mishra, University of New Orleans, dmishra@uno.edu; Robert G. Wilson, Panhandle Research and Extension Center, rwilson1@unl.edu; Patrick Reece, Panhandle Research and Extension Center, preece1@unl.edu; Ann Kohler 
Description

This research focused on the dominant invasive plant species in Nebraska, including saltcedar, Russian olive, Canada thistle, and musk thistle. Once established, these invasive species can have several harmful effects, such as increasing (1) soil salinity, which reduces productivity of native plants and results in the loss of natural habitat (Pimentel et al. 2000); (2) soil water consumption to such an extent that it can dry up streams and reduce water levels of rivers and lakes (Friederici 1995); (3) risk of wildfires during summer (Brooks et al. 2004); and (4) chances of flooding during high-intensity rainfall by impeding stream flow (Zavaleta 2000).

The study area was a corridor approximately 1.6 km wide and 257 km long located along the North Platte River starting at the Wyoming/Nebraska border and ending at Kingsley Dam on Lake McConaughy. The elevation ranges from 1,244 m above sea level at the Wyoming/Nebraska state line to 943 m, in an area below Kingsley Dam. The Platte River is generally considered to be a braided river with a network of small channels separated by large and small islands and sandbars. It has been noted that historically the banks of the Platte River were rarely covered with trees but instead with grasses and sedges (Farrar 1983; Kuzelka et al. 1993). Some of the islands were wooded, and willows (Salix exigua) and cottonwood (Populus deltoids) trees were observed. In the 1930s, Russian olive was introduced into the region for conservation plantings. It has rapidly spread along the Platte River, replacing willows and cottonwoods. More recently, saltcedar has also invaded the study area from the west and, along with Russian olive, occupies riverbanks, sandbars, and islands. Saltcedar seedlings are tolerant of shade and thrive in a variety of soil and moisture conditions, but especially saline soils.

When examined from a comprehensive perspective for the entire study area (22 flight lines) from the Nebraska/Wyoming Border to Kingsley Dam, invasive plants covered an area of 139,632 ha, of which 1,965 hectares (2% of the total area) were identified as saltcedar and 1,478 hectares (1.1% of the total area) as Russian olive. The three mixed classes occupied approximately 5% of the total area. These numbers indicate the severity of invasion of nonnative species along the North Platte River. Nonnative species such as saltcedar have been known to consume large quantities of water, and because western Nebraska is frequently affected by drought, mapping and monitoring their spread along the river corridor can aid in the implementation of biological, mechanical, chemical, or some combination of these control mechanisms to minimize the effects on water resources.

Effective control and management of an invasive species begins with its detection and inventory. The ability to detect invasive plants with the use of remotely sensed data has improved with new sensors, enhanced technology (e.g., hyperspectral), and innovative image processing techniques. However, datasets that have the highest likelihood of detecting invasive plants come with high fiscal and technical considerations. When compared with low-resolution multispectral data, airborne hyperspectral data is most appropriate for detecting subtle changes in the reflectance properties of various vegetation species present in the landscape (Narumalani et al. 2006).

Project Support n/a
Project Website http://snr.unl.edu/invasives/file/northplatte_sunil_deepak.ppt
Report Narumalani_Platte.pdf
Current Status Published in Weed Technology 2009 23:99-107
Topic Production Agriculture
Project's Primary Contact Information
Name Ferguson, Richard
Unit Agronomy and Horticulture
Email rferguson1@unl.edu
Phone 402-472-1144
Web Page http://agronomy.unl.edu/ferguson
Project Information
Title Interactions of Water and Nitrogen Supply for Irrigated Corn across Field Landscapes
Other(s) Tim Shaver, West Central Research & Extension Center, tim.shaver@unl.edu; Nicholas Ward, Agronomy & Horticulture, ward.nick.c@gmail.com; Suat Irmak, Biological Systems Engineering, sirmak2@unl.edu; Simon van Donk, West Central Research & Extension Center, simon.vandonk@unl.edu; Daran Rudnick, Agronomy & Horticulture, daran.rudnick@huskers.unl.edu; Brian Wienhold, Agronomy & Horticulture, bwienhold1@unl.edu 
Description

Water and nitrogen (N) supply to a crop can interact throughout the growing season to influence yield potential. The increasing availability of variable rate irrigation systems to growers in irrigated regions, along with existing capacity for variable rate fertilization, provides the opportunity for temporal and spatial management of inputs of water and nitrogen. This study was initiated in 2011 to explore interactions of landscape and soil features with water and N inputs on grain yield and water and N use efficiency. Five field locations were used across Nebraska to evaluate the effects of landscape variation, climate, and capacity for temporal and spatial management of water and N. Preliminary results in 2011 showed that at sites with significant topographic variation these features influenced grain yield as much as the rate of irrigation water or nitrogen fertilizer, indicating the importance of considering spatial variation in landscape features when optimizing rates and timing of water and nitrogen.

Five field locations were used for the study in 2011. Two sites were at University of Nebraska-Lincoln (UNL) research laboratories the South Central Agricultural Laboratory (SCAL) and the Brule Water Resources Laboratory (BWL). Three sites were located on cooperating producer’s fields one in Morrill County, and two in Hamilton County. The UNL research sites included more detailed measurements, and inclusion of treatments that were more yield-limiting than those on producer fields. Locations were situated across a rainfall and soils gradient in Nebraska, allowing evaluation of site-specific water/N management interactions over a range of annual rainfall and soil types. Three of the sites included the use of variable rate irrigation systems and two of the sites implemented canopy sensor-based in-season N treatments.

Project Support John Deere
Project Website
Report Ferguson_Landscape.pdf
Current Status Completed
Pic 1 Project Image
Pic Caption 1 Study locations in 2011, with precipitation gradient across Nebraska 
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 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 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 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 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 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 Recruitment of Walleye and White Bass in Irrigation Reservoirs
Other(s) Jason DeBoer, Robert Kill and Christopher Lewis, Graduate Students; Ryan Lueckenhoff (MS 2011), Dustin Martin (MS 2008) 
Description

The five reservoirs within Nebraska’s Republican River watershed (Swanson, Enders, Red Willow [also referred to as Hugh Butler Lake], Medicine Creek [Harry Strunk Lake], and Harlan County) were built primarily for flood control and irrigation, resulting in large in-reservoir water-level fluctuations within and among years. These reservoirs also provide important fisheries for anglers in southwest Nebraska. Walleye and white bass are of particular importance in these reservoirs. However, continued annual stockings of walleye are necessary because natural production is limited. In contrast, white bass populations are self-sustaining within these reservoirs, although recruitment is extremely erratic (i.e., weak or missing year-classes are common) in all but Harlan County Reservoir. A recruitment bottleneck likely exists for walleye and perhaps white bass in these irrigation reservoirs.

GOALS: The purpose of this project is to gain an understanding of the factors affecting recruitment of walleye and white bass in irrigation reservoirs. The primary foci are documenting the relative Catching walleye with an electro-fisherimportance of spawning habitats and determining when the suspected recruitment bottleneck for walleye and white bass occurs in southwest Nebraska irrigation reservoirs. This information is vital for understanding reservoir fish ecology in semiarid regions.

CURRENT STATUS: Sampling walleye and white bass populations continues in these reservoirs. Several more years of data are needed to begin initial explorations for potential recruitment bottlenecks of walleye and white bass in southwest Nebraska irrigation reservoirs. We have finished processing otoliths from fall gillnet surveys conducted with Nebraska Game and Parks Commission from 2007–2011, which allows us to evaluate the age structure of the walleye and white bass populations in these reservoirs. Furthermore, mathematical models are allowing us to gain insight into the mechanisms affecting recruitment of walleye and white bass, and the spatial scale at which these mechanisms are operating. Future efforts include comparing walleye egg size (theoretically related to reservoir productivity) among reservoirs, and evaluating larval white bass feeding efficiency under variable turbidity conditions and zooplankton densities.

In an effort to improve the walleye fishery in the reservoirs, annual stocking strategies are being evaluated. The effect of in-reservoir water-level fluctuations on the success of walleye stocking is being examined, with the goal of constructing a mathematical model to predict maximum stocking efficiency.

Project Support Nebraska Game and Parks Commission
Project Website http://snr.unl.edu/necoopunit/research.main.html#Recruitment_of_Walleye_and_White_Bass_in_Irrigation_Reservoirs
Report
Current Status Continuing
Topic Wildlife
Project's Primary Contact Information
Name Pope, Kevin (advisor)
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 Impact of White Perch on Walleye and Predators of White Perch at Branched Oak and Pawnee Reservoirs
Other(s) Nathan Gosch, Graduate Research Assistant 
Description

Habitat alterations and accidental introduction of white perch into Branched Oak Lake have shifted the fish community from one dominated by littoral (near-shore) species (e.g., largemouth bass and bluegill) to one dominated by pelagic (open-water) species (e.g., white perch and gizzard shad). Along with the change in the fish community, angler trips to Branched Oak Reservoir have declined by 85% over the last two decades. Further, the white perch population has become stunted, meaning there is a high density of slow growing individuals that mature at a small size. Like Branched Oak Lake, Pawnee Lake historically supported an active and diverse fishery, and has experienced similar habitat alterations and accidental introduction of white perch; however, unlike Branched Oak Lake, stunting has not yet occurred for the white perch population in Pawnee Lake.

Studies at both lakes enable researchers to examine white perch interactions with other fishes in two similar Nebraska reservoirs having different white perch population stages (i.e., stunted and non-stunted). Food habits and diet overlap among white perch, crappie, walleye, white bass, and channel catfish are being evaluated. To study diet, fish stomachs are pumped and the contents analyzed to understand which fish species prey on white perch. All stomach content samples are analyzed and data synthesized. Stable isotope analyses of stomach contents have been conducted and the results confirmed.

By documenting the potential competition bottlenecks that exist between white perch and other fish species of importance, management program may be developed to eliminate stunted status for the white perch population in Branched Oak Lake and to prevent stunting of the white perch population in Pawnee Lake.

Project Support U.S. Geological Survey, Nebraska Game and Parks Commission
Project Website http://www.nlc.state.ne.us/epubs/U1500/B011-2008.pdf
Report
Current Status Completed - report available