NU Water-Related Research in York County

There is a critical need to accurately and efficiently assess and manage water quantity. This is a challenge because water management is conducted under conditions of uncertainty about current and future water resources. Adaptive water management has become the policy heuristic for flexible water management that responds to ever changing physical and social demands. The central challenge of the Adaptive Management approach is the need to quantify the uncertainty in observed water measurements.

The long-term goal of this project is to develop intelligent, scalable decision support tools for collaborative systems that incorporate uncertainty to analyze and integrate hydrological data and information. The framework is powered by knowledge discovery, information fusion and visualization tools, that:

• assist hydrologists developing comprehensive models and metrics for the analysis of the water cycle;
• supports decision makers in adaptive management determinations;
• increases confidence in water data for adaptive managers, policymakers, and water users; and
• helps policy makers study the social and legal impact on water users.

The project addresses several research aspects of collaborative systems, including knowledge discovery and information fusion applied in a digital government domain. Part of the project also includes collaboration with Hohai University (Nanjing, China) to develop cross-national research relevant to water management issues.

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

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

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

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

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

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

Sediment core samples were categorized into four groups:

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

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

This project will explore the ability of chemical additives to direct the formation of products in alkene ozonolysis, one of the most important oxidative transformations in organic chemistry. While the central role of carbonyl oxides in alkene ozonolysis has been known for more than a half century, the scope of reagents able to react with these short-lived intermediates remains extremely limited. The hypothesis central to the research is that the presence of specific additives will control the reactivity of the intermediate carbonyl oxides to favor formation of particular products, some of which are completely unavailable by traditional methodology. The project will focus on three areas: First, the generation and fragmentation of carbonyl oxide-derived zwitterions will be investigated as a new approach for \"reductive\" ozonolysis, a process which directly produces carbonyl products without the need for a separate reductive step. Second, ozonolysis in the presence of Lewis acids will be explored as a means for enhancing nucleophilic trapping of carbonyl oxides. Finally, generation and fragmentation of heteroozonides will be explored for the direct conversion of alkenes to carboxyl groups.

Click here to read a journal article about Ozonolysis

Click here to read another journal article about this research

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