Category: Statewide

Concern about the impact of ethanol production on Iowas water resources has increased due to the large increase in statewide ethanol production. Water use at ethanol plants could soon reach 22 billion gallons per year (Ggal/yr). Groundwater is preferred for these operations because of its high quality and stable quantity; however, placement of ethanol plants is determined by access to corn, not necessarily to groundwater supply. Permits for ethanol-related groundwater withdrawals are being granted in rural areas where determination of local pumping impact is often performed by a well driller or consultant. Tools for assessing the larger-scale impacts of ethanol production in aquifers (including water quality and ecological impacts) and for evaluating the sustainability of aquifers in the State need to be developed in order to provide a scientific basis to strengthen administrative oversight of groundwater use. The proposed research will compare the ability of three different types of groundwater models to assess the potential impact of ethanol production and determine aquifer sustainability using a test case of the Ames aquifer a regional, alluvial/buried valley aquifer in central Iowa. The grant will help fund Phase III of the project Water Supply for Ames in the 21st Century: A Comprehensive Reassessment of the Ames Aquifer and will address the following objectives: 1. Simulate steady-state and transient groundwater flow in the Ames aquifer under non-pumping and pumping conditions using a 3-D, finite-difference, groundwater flow model; 2. Compare output of 2-D and 3-D groundwater models to determine which would best identify impacts of ethanol production in aquifers and the appropriate scale of investigation; 3. Apply simulation-optimization modeling to the calibrated 3-D model to investigate the impact of large-scale ethanol development on drawdown, optimize well pumping schedules, manage future well field expansion, and assess the long-term sustainability of the aquifer. Modeling will take advantage of three USGS stream gages in Squaw Creek and the Skunk River, 65 hydraulic head targets, and nearly 100 boring logs in the Ames aquifer that have been used to construct a 3-D framework for the aquifer. In order to further understand the geology, the 3-D distribution of hydraulic head, and estimate recharge rates for the model, funds are requested for the installation of two new piezometer nests. Nest 1 in the Downtown Well Field would be designed specifically to estimate vertical K (Kv) and recharge (R) in the aquitard. Nest 2 in the Skunk River alluvium will specifically test the hypothesis that the Skunk River is a losing stream and can develop an unsaturated zone beneath the river. Both piezometer nests will be installed in fall 2007 and instrumented with combination pressure transducers/ dataloggers (corrected for barometric pressure) in order to gather real-time data that can be related to pumping schedules and USGS stream gaging data. Modeling with MODFLOW will begin in July 2007 and the simulation will be calibrated to hydraulic head measurements in the model domain and streamflow under pre-development conditions. Transient simulations will commence once the model is calibrated. Results of a regional 2-D, steady-state, analytic element, groundwater/surface water model (GFLOW) and a local-scale, 3-D, transient, groundwater flow model (MODFLOW), will be compared to determine which approach is best suited to evaluating the impacts of ethanol production at different scales. A simulation-optimization model (the Groundwater Management process for MODFLOW 2005) will be applied in spring 2008 to evaluate the sustainability of the Ames aquifer, taking into account limits on groundwater withdrawals, streamflow depletion under multiple uses (pumping) of the aquifer, and alternative climatic scenarios. By using models to assess the impact of ethanol production and to address sustainability for the Ames aquifer, the results of this study will provide a template to guide management and regulation of similar aquifers under pumping stresses from ethanol production in Iowa and the Midwest.

Interest in biorenewable energy is increasing due to concerns associated with continued reliance on fossil fuels. As the primary producer of crops used as feedstocks for ethanol production and other biorenewable energy sources, the Midwest in general, and Iowa in particular, is likely to incur a high percentage of the benefits and costs of the biorenewable energy initiative. Of significant potential concern is the impact of feedstock selection, management, and harvest on nutrient and sediment losses to receiving water bodies and the resulting impact on the integrity of aquatic resources. In the short term, increases in corn acreage, or large-scale conversion of Conservation Reserve Program lands to feedstock production, have the potential for significant negative impacts on water resources. In the longer term, conversion to perennial-plant based feedstocks for cellulosic feedstocks has great potential to positively impact aquatic integrity and water quality. However, in order to make a credible assessment of impacts of such change, significant knowledge gaps regarding the function of such landscape features need to be addressed. Managed riparian buffers, composed of woody and nonwoody vegetation, are being used to reduce inputs of nutrients, sediments, and chemicals to streams that commonly result from intensive agriculture. In central Iowa, previous studies conducted by the Iowa State University Agroecology Issue Team demonstrated that buffer attributes (e.g., physical structure, root uptake) reduce nutrient and sediment loading to streams. However, responses of most ecosystem components, including populations and communities of aquatic organisms, remain poorly studied. The emerging biorenewables initiative is likely to generate even greater agricultural production, particularly on lands susceptible to high runoff and soil erosion. Therefore, it is critical that we identify functional qualities (e.g., spatial distribution, length and width, vegetation composition and age) of effective riparian buffers and apply this knowledge to design and manage systems that protect aquatic ecosystems in an economically-viable manner. Animal and plant populations and communities respond to and reflect all physical, chemical, and biological attributes of their environment, including conditions affecting human health. Additionally, biological communities are sensitive to episodic events (e.g., pulses of contaminant inputs during high surface-water runoff) and rare contaminants that are undetected by periodic measurement of selected physical and chemical ecosystem attributes. Because organisms are now acknowledged to be definitive indicators of water quality, they are increasingly being used for regulatory assessments (e.g., USEPA) and are likewise essential tools for assessing riparian buffer effectiveness. In this study, invertebrate and fish community characteristics (i.e., species composition, abundance, growth) will be evaluated in three central Iowa streams with and without managed riparian buffers of different age, size, and structure (N = 40 total stream reaches). Instream habitat features (e.g., streambed substrate particle sizes, coarse particulate matter abundance, temperature, turbidity) will also be measured in riffles, pools, and runs where fish and invertebrates are sampled. Results of this study will produce quantitative measures of buffer effectiveness that will help guide future riparian management strategies in agroecosystems. In addition, this study will provide a platform for expanding the scope and scale of our investigations. Planned studies to increase mechanistic understanding of riparian buffer effects in agroecosystems include analyses of buffer effects on stream metabolism (e.g., dissolved oxygen, primary production), and nutrient- and energy-flow pathways through aquatic food webs. The proposed research will also provide a platform for investigating emerging issues across Iowa. Issues include conservation of systems influenced by production of biorenewable feedstocks (i.e., cereal grains, cellulosic materials in riparian buffers), lake and reservoir restoration activities, and biological assessment of recently reclassified headwater stream systems.

Improved watershed modeling, uncertainty analysis and statistical techniques for TMDLs have been identified as immediate TMDL science needs by the National Research Council (US EPA 2002). Recently approved sediment TMDLs in Iowa use versions of the Universal Soil Loss Equation (USLE) with conservation input to account for uncertainty. The uncertainty associated with these USLE estimates cannot be explicitly quantified and the margin of safety (MOS) required by the TMDL program is considered to be implicit in the watershed modeling process. This project proposes to test the following hypothesis: The uncertainty associated with sediment TMDLs can be quantified by applying the process-based Water Erosion Prediction Project model (WEPP) and an explicit computation of the margin of safety (MOS).

The quality and quantity of groundwater resources in Iowa are a growing concern because of increased pressures on quantity and concerns about contamination. Interactions between land management, groundwater, and surface water are conceptually well understood but the impact of temporal shifts on groundwater and surface water are largely unknown. Groundwater and streamwater quality are of particular concern in cities such as Ames because of their reliance on groundwater as a water supply. Recent monitoring near College Creek in Ames identified nitrate in groundwater at two of four transects and significant total P and SRP concentrations present in all 12 wells and in streamwater. Recent groundwater modeling of the Ames aquifer suggests direct interaction between surface water transported through tributaries running through the city and the Ames aquifer. Because most streams that enter the alluvium of Squaw Creek and South Skunk River becoming losing streams at that point, contaminants in the streams will impact the city’s water supply. Thus, efforts to prevent contaminants from getting to streams in headwater areas are necessary to protect groundwater quality downstream. Those responsible for the contaminant loading become as important as the presence of the contaminants themselves. This research proposes the addition of a strongly integrative groundwater-streamwater component to an ongoing urban stormwater research/non-point source pollution research and stream stabilization effort on College Creek in Ames. Our proposal occurs at an interesting and exciting time for College Creek and the Ames community. The City of Ames is partnering with ISU researchers whose work with water resources in the community are supported by multiple agencies and institutions. The City also committed $291,540 of its operating budget over the next three years to match an IWIRB grant they were awarded for College Creek stream stabilization and riparian enhancement. As this momentum for addressing non-point source pollution grows, it is also understood that only a very limited amount of research has been dedicated to exploring groundwater from the perspective of the urban residentthe group likely responsible for much of the contaminant loading occurring in headwater areas. This proposal includes an innovative community-based education based on biophysical and social investigations of the urban groundwater-streamwater system at the neighborhood scale. We focus specifically on interactions between land management, groundwater, soil water and streamwater within the urban residential landscape. Monitoring of a nested well site adjacent to College Creek in Ames is accompanied by simultaneous investigation of groundwater perceptions and technical understanding among a statically representative sample of urban, riparian landowners. Research activities are organized to utilize the results from each component to inform the others. Early monitoring results are utilized to develop a social assessment tool to characterize the perceptions & misconceptions residents hold concerning local hydrologic processes and conditions. Social assessment results add landowner behavior data that, when integrated with monitoring and modeling, contribute to a greater understanding of nutrient movement between the landscape and hydrologic system. Finally, educational curriculum is developed to integrate both monitoring results as well as any lack of understanding or misconceptions identified during social assessment.

Excess sediment, phosphorus (P) and nitrogen (N) impair the majority of Iowa lakes and many streams also are impaired during some periods of the year. Most sediment and nutrients originate from agricultural fields or stream banks. A good potential for large-scale bioenergy production in Iowa is challenging researchers and nutrient management planners to develop crop and nutrient management systems to maximize production of feed, fuel, and fiber while utilizing soil and nutrient resources minimizing undesirable environmental impacts. Therefore, there is a need for studies of soil processes and nutrient loss on a field-plot scale that represent actual field conditions as much as possible focusing on bioenergy production and nutrient management systems likely to be adopted soon. The project will evaluate and compare systems that will still predominate for years to come in Iowa (such as corn and soybean for grain production) and new systems with likely adoption for bioenergy production (such as total or partial corn and perennial grass biomass harvest) managed with fertilizer or liquid swine manure. The study results will provide needed information about cropping and management systems for bioenergy production impacts on soil and water quality that can be compared to impacts from currently used systems. The proposed work will integrate efforts by scientists from the Department of Agronomy and the Department of Agricultural and Biosystems Engineering, by the ISU Research and Demonstration Farms System, a group of Northwest Iowa farmers (the Northwest Iowa Experimental Association), and seed funding by the IFLM program of IDALS. These contributions plus requested funding from the Iowa Water Center will be used to develop work during 2008 and 2009 at a runoff study site in Northwest Iowa and a tile-drainage study site in Central Iowa. We propose to study how crops, biomass harvesting systems, fertilizer and manure management practices, and selected soil properties relate to loss of sediment and various forms of N and P with surface runoff and subsurface tile drainage. The main objectives are (1) to determine dissolved reactive P, total dissolved P, algal-available P, total P, and total N concentrations and loads in surface runoff from corn production systems harvested for grain using different tillage and fertilizer or manure P management systems and from continuous corn harvested for grain and cornstalks and (2) to determine loss of nitrate, dissolved reactive P, and total dissolved P through subsurface tile drainage from crops for selected bioenergy production systems managed with fertilizer or manure N-P management systems. We will also analyze soil and harvested biomass for nutrient concentration and relate these results to treatment effects on N and P loss. Overall, the information from the study will be useful to establish new and improved environmentally oriented management guidelines and will provide useful information concerning impacts of anticipated land changes in the near future on export of nutrients to water resources.

Surface water from the Des Moines River is impaired by nitrate-nitrogen for drinking water use. Saylorville Reservoir is a 24.1 km2 impoundment of the Des Moines River located approximately 10 km north of the City of Des Moines. Monthly mean nitrate concentration data collected upstream and downstream of the reservoir for a 30-year period (1977-2006) are analyzed in this study. Our objective is to improve understanding of the reservoir effects on river nitrate concentrations. We hypothesize that monthly water quality downstream of the reservoir depends on the current monthly upstream water quality and its past lags. The dynamic relation is studied via a transfer function model that is shaped by reservoir characteristics such as surface area, volume, and discharge. Research results may used to better manage Saylorville Reservoir to mitigate nitrate concentrations in downstream receiving waters and forecast potential impairment to the Des Moines Water Works.

Runoff from open beef feedlots is a contributor of nutrients to the surface waters of Iowa. Currently, efforts are underway to improve the runoff control systems on open feedlot operations of all sizes. Both the Iowa Small Feedlot Team (comprised of ISU faculty and staff, Iowa DNR, and the NRCS) and the Iowa DNR expect vegetative treatment systems to be one of the lower cost, effective runoff control options that Iowa feed-lots can use to reduce beef feedlot runoff impacts on water quality. Improved understanding of the transport and fate of nitrogen and phosphorus within and from vegetative treatment systems is necessary to improve system design and to understand long term effectiveness of the treatment system. Currently, the Iowa State University – Vegetative Treatment Area model used to design and evaluate vegetative treatment system performance is based on runoff control system hydrology. Likewise, system performance has been evaluated based on effluent flow into and out of the treatment system. To improve the design capability of the Iowa State University – Vegetative Treatment Area model and performance of these runoff control systems, nutrient transport and fate needs to be considered. The objective of this proposal is to investigate the dynamics and transport of phosphorus and nitrogen applied to the vegetative treatment area. We propose to: • Measure phosphorus sorption isotherms on soils obtained from four vegetative treatment systems in Iowa • Determine nitrogen mineralization rates for feedlot runoff • Develop phosphorus budgets for four vegetative treatment systems in Iowa • Develop preliminary nitrogen budgets for four vegetative treatment systems in Iowa The deliverables produced as a result of this study will include: • Design guidance for sizing a vegetative treatment systems based on phosphorus loading • Design guidance for sizing a vegetative treatment systems based on nitrogen loading This data will be in direct support of the Iowa Small Feedlot Teams efforts to develop runoff control strategies for open beef feedlots. Data from this study will be used to develop guidance documents for appropriate VTS sizing and ultimately to add nitrogen and phosphorus simulation capabilities to the Iowa State University – Vegetative Treatment Area model. Developing these tools will provide consultants, NRCS, the Iowa DNR, and the Iowa Small Feedlot Team with the tools necessary to install more effective runoff control systems on open feedlots, protecting the waters of Iowa. The results of this study will be used as preliminary data to seek additional funding from the USDA – Agriculture and Food Research Initiative Competitive Grants Program to further evaluate the fate and transformations of nitrogen and phosphorus occurring in these systems. Future research topics that we will seek additional funding from USDA to investigate include; quantification of nitrogen leaching from the treatment area, measurement of gaseous nitrogen emissions from the treatment system, and measurement of the mineralization of organic phosphorus.

The sediment in transport within a stream is a complex mixture of eroded upland surface soils, collapsed channel bank material, and resuspended bed sediments. The proportion of sediment contributed from each primary source (i.e., uplands, banks, and bed) is affected by the relative rates of the dominant erosion processes occurring in a watershed. As we still deal with the daunting problem of water quality degradation by high sediment loads, the following question remains: “What are the contributions from each of the primary sources during a storm event and how do these contributions vary in space from the headwaters to the mouth of a watershed?” Upland erosion rates in Iowa watersheds are relatively high for the U.S. (e.g., Cruse et al., 2006). However, channel sources in some streams during extreme events can contribute up to 80% of the stream load (e.g., Wilson et al., 2008). The key objective of this research is to identify the major source(s) of sediment to the stream load of an anthropogenically altered watershed in SE Iowa, the Clear Creek, IA watershed (CCW). This information will provide better understanding of the relative roles of upland and channel erosion processes in the delivery of sediment to local streams. Identifying the major source(s) of sediment to the stream load will also allow for better focusing of remediation efforts to abate another predominant water quality concern in Iowa, namely high sediment-associated P loads. Transport and mixing of sediment-associated P in rivers often constitutes a high percentage of (23-61%) of the total annual P load (e.g., Lick, 2009). We propose to use established tracing techniques, such as the naturally occurring radionuclides, 7Be and 210Pbxs, for identifying the proportions of sediment derived from each primary source (i.e., uplands, banks, and bed) under different magnitude hydrologic events, including floods. In particular, 7Be has shown the unique ability to differentiate upland soils from stream bank and bed sediments (e.g., Wilson et al., 2008). 7Be is produced continuously in the atmosphere but delivered to the earth surface in high concentrations mainly during precipitation events. Moreover, 7Be does not remain long in the soil before decaying due to its relatively short half-life of only 53 days. Thus, there is a strong relationship between a single erosion event and high signatures of 7Be in the eroded upland soils. To meet our research goal, a comprehensive study is designed that takes advantage of existing monitoring and database infrastructure in the CCW. First, we will construct sediment rating curves (i.e. flow discharge vs. sediment flux curves) using existing in-situ, measuring instrumentation for flow discharges and sediment fluxes [Task 1]. We will partition the sediment sources corresponding to each event by analyzing the radionuclide activity of collected grab samples through gamma spectroscopy in the laboratory. The activities of the grab samples will be compared against the radionuclide activities of sediments extracted from the primary sources, namely, the uplands, channel banks, and stream bed. An established unmixing model (Fox and Papanicolaou, 2007) will be used to isolate the fraction of each primary source contributions in terms of mass (or volume) [Task 2]. The data from this study will be incorporated in the Clear Creek Digital Watershed and used for model verification and model refinement [Task 3]. These rare data will allow us to quantify for the first time the sediment fluxes from different sources under different hydrologic conditions and will lead to the refinement and extension of sediment rating curves applicable to most Midwestern agricultural watersheds. If we can quantify the dominant sediment source(s) in streams, we can identify the areas, which need BMPs to control sediment-bound P, and design our BMPs more efficiently. The results will be disseminated in EOS and the journal of Soil Water Conservation (JSWC). This study will support a Master’s level student and laboratory sediment analysis.

Problem: Urban watersheds are composed of a complicated spatial fabric and are influenced by a wide range of often competing economic, policy, and public interest drivers and constraints. With increased regulation of stormwater discharges taking place on a national basis, there are greater pressures on municipalities to develop effective urban stormwater management strategies. In addition, highlighted by recent events in Iowa, there is great interest in flooding and potential mechanisms for better managing the landscape, including urban areas, to improve hydrologic response and reduce damaging flooding events. To these ends, there is a great need for effective tools which can aid the design and execution of such strategies by identifying hot-spot areas contributing to excessive discharges and pollutants and to evaluate potential best management practices. Methods: This project will address urban hydrological problems in the first instance and year by developing processes for incorporating Light Detection and Ranging (LiDAR) elevation data into modeling processes using an industry-standard urban watershed model (WinSLAMM). Iowa is one of the first states in the country to have state-wide coverage of LiDAR data and this presents an opportunity to develop improved WinSLAMM modeling processes using LiDAR data. These processes will be initiated in the Dry Run Creek (an impaired waterway) watershed (85% of Cedar Falls) and then transferred to the Catfish Creek watershed which overlaps with large portions of Dubuque. In the event of second year funding, a new ArcGIS extension, called ArcWinSLAMM, will be developed. This extension will provide more efficient mechanisms for input parameterization of WinSLAMM and allow for easier visualization of modeled results. The extension will be developed with standard application development tools and will be made freely available. The development process will include beta testing by personnel with WinSLAMM modeling experience. In addition, training sessions for using the new ArcWinSLAMM extension will be provided at the end of the project. Objectives: The goals of the project include the development and demonstration of more effective WinSLAMM modeling processes utilizing LiDAR topography data in the Dry Run Creek and Catfish Creek watersheds, the development of a freely available ArcGIS extension which will improve efficiency and accuracy in WinSLAMM modeling, and technology transfer in the form of training and provision of the free extension. The project will lead to novel techniques and technologies, adoptable throughout the country, for addressing both water quality and quantity (flooding) issues in urban watersheds.

The sediment in transport within a stream is a complex mixture of eroded upland surface soils, collapsed channel bank material, and resuspended bed sediments. The proportion of sediment contributed from each primary source (i.e., uplands, banks, and bed) is affected by the relative rates of the dominant erosion processes occurring in a watershed. As we still deal with the daunting problem of water quality degradation by high sediment loads, the following question remains: What are the contributions from each of the primary sources during a storm event and how do these contributions vary in space from the headwaters to the mouth of a watershed? Upland erosion rates in Iowa watersheds are relatively high for the U.S. (e.g., Cruse et al., 2006). However, channel sources in some streams during extreme events can contribute up to 80% of the stream load (e.g., Wilson et al., 2008). The key objective of this research is to identify the major source(s) of sediment to the stream load of an anthropogenically altered watershed in SE Iowa, the Clear Creek, IA watershed (CCW). This information will provide better understanding of the relative roles of upland and channel erosion processes in the delivery of sediment to local streams. Identifying the major source(s) of sediment to the stream load will also allow for better focusing of remediation efforts to abate another predominant water quality concern in Iowa, namely high sediment-associated P loads. Transport and mixing of sediment-associated P in rivers often constitutes a high percentage of (23-61%) of the total annual P load (e.g., Lick, 2009). We propose to use established tracing techniques, such as the naturally occurring radionuclides, 7Be and 210Pbxs, for identifying the proportions of sediment derived from each primary source (i.e., uplands, banks, and bed) under different magnitude hydrologic events, including floods. In particular, 7Be has shown the unique ability to differentiate upland soils from stream bank and bed sediments (e.g., Wilson et al., 2008). 7Be is produced continuously in the atmosphere but delivered to the earth surface in high concentrations mainly during precipitation events. Moreover, 7Be does not remain long in the soil before decaying due to its relatively short half-life of only 53 days. Thus, there is a strong relationship between a single erosion event and high signatures of 7Be in the eroded upland soils. To meet our research goal, a comprehensive study is designed that takes advantage of existing monitoring and database infrastructure in the CCW. First, we will construct sediment rating curves (i.e. flow discharge vs. sediment flux curves) using existing in-situ, measuring instrumentation for flow discharges and sediment fluxes [Task 1]. We will partition the sediment sources corresponding to each event by analyzing the radionuclide activity of collected grab samples through gamma spectroscopy in the laboratory. The activities of the grab samples will be compared against the radionuclide activities of sediments extracted from the primary sources, namely, the uplands, channel banks, and stream bed. An established unmixing model (Fox and Papanicolaou, 2007) will be used to isolate the fraction of each primary source contributions in terms of mass (or volume) [Task 2]. The data from this study will be incorporated in the Clear Creek Digital Watershed and used for model verification and model refinement [Task 3]. These rare data will allow us to quantify for the first time the sediment fluxes from different sources under different hydrologic conditions and will lead to the refinement and extension of sediment rating curves applicable to most Midwestern agricultural watersheds. If we can quantify the dominant sediment source(s) in streams, we can identify the areas, which need BMPs to control sediment-bound P, and design our BMPs more efficiently. The results will be disseminated in EOS and the journal of Soil Water Conservation (JSWC). This study will support a Masters level student and laboratory sediment analysis.