Nutrient enrichment of Iowa’s water bodies is one of the most critical issues the state is currently facing. Intensive farming and heavy nutrient application in the Midwest coupled with an extensive subsurface tile drainage network leads to excessive nutrients entering surface waters. Of the nutrients entering Iowa’s surface waters, nitrate is one of the most critical due to its contribution to harmful algal blooms (HABs) not only in the Midwest, but also in the Gulf of Mexico. Nitrate receives attention from researchers, farmers, and the general public because it travels in subsurface tile drainage and causes HABs. There is a long history of research conducted to reduce nitrate transport to water bodies from drainage. Phosphorous (P) also contributes to HABs and at lower concentrations, but its pathways are less understood by researchers. Recent work has begun to document the significant export of phosphorous through drainage systems. Woodchip bioreactors are one of the most cost effective and least invasive methods to remove nitrate from subsurface drainage. By installing these systems at the edge-of-the field, there is potential to expand the range of pollutants removed by woodchip bioreactors to include phosphorous. The goal of the proposed project is to evaluate the ability of woodchip bioreactors to remove phosphorous by adding biochar as a P amendment to the bioreactor. Objectives of the study are (1) to assess the effectiveness of different amendments on P removal in bioreactors and (2) to analyze the effect of influent P on overall removal. The study will be carried out in the Water Quality Research Laboratory (WQRL) at Iowa State University where there are three bioreactor columns available for use to complete a P amendment column study. We will analyze a range of enhanced biochars as an amendment, including three types of pyrolysis, biochar treated with Magnesium, and organic material sourced from corn stover, hardwood, and softwood. Results of the proposed project will include identification of viable P amendments to enhance the nutrient removal of woodchip bioreactors suitable for a range of applications.
Spatial Potential for Enhanced In-field Denitrification from Perennial Vegetative Filter Strips
Iowa’s waterways receive excessive nitrogen from agricultural lands. This project aims to identify the spatial specifics of a conservation practice that has demonstrated abilities to promote denitrification within agricultural fields, perennial vegetation filter strips. We have a strategy to identify the locations with the greatest potential for denitrification due to interactions between the filter strip and landscape processes resulting in changes in the soil environment. To do so, we will create and use a linear, fuzzy logic model to predict potential denitrification areas (PDA). The framework includes the spatial distribution of environmental factors which are conducive for denitrification following the following form: PDA= f (OC, T, pH, θv) where OC is a measure of accessible, oxidable carbon, T is a measure of favorable thermal conditions, pH is hydrogen ion activity, and θv is a measure of water holding capacity. In our current work, we have already observed the impact these filter strips are having on soil properties, affecting a greater area than generally assumed. Among those impacts, is a strong increase in θv within and surrounding the filter strips. This change in the soil environment suggests that if the other factors are present in the right combinations the capacity for denitrification in unsaturated hillslopes with perennial vegetation filter strips may also be increasing. Our research is unique in that it quantitatively accounts for the interaction between the hillslope morphology, hydrology, and the filter strips, which allows us to pinpoint the spatial interactions. Although impacts of perennial vegetation filter strips on water quality at the small catchment scale have been documented, the spatial distribution of the processes producing those impacts within the field has yet to be explored. By adding the soil sample analysis proposed here, our spatial modelling will create a map of PDA. The production and analysis of this map will assist in identify optimal filter strip design for increasing PDA.
The Economic Benefits of Mitigating Harmful Algal Blooms in Iowa
Since 2006, the Iowa Department of Natural Resources has issued 190 advisories at state park beaches because of high levels of microcystin produced by harmful algae. Among those advisories, 142 were issued in the last five years, with a record 37 advisories issued in 2016. Microcystin was also detected in treated drinking water of Des Moines in 2016. While harmful algal blooms (HABs) can have adverse impacts, such as increased drinking water treatment costs and limiting recreational usage of waterbodies, the economic impacts of HABs in Iowa have not been studied. The proposed two-year project will conduct a comprehensive assessment of the economic benefits of mitigating HABs in Iowa. The benefits from improved drinking water safety, recreational opportunities, property values, and water aesthetics will be monetized using state-ofthe-art economic valuation methods. In the first year of the project, we will conduct a survey of Iowa citizens to gauge their awareness and attitude toward HABs and related issues including concerns about lake beach advisories and excessive levels of microcystin in drinking water. The survey data will also be used to monetize the benefits of mitigating HABs. In the second year, we will integrate the housing transaction, lake visitation, and water quality data to quantify the impacts of HABs on property values and recreation activities in Iowa. This study will (1) advance the understanding of socio-economic impacts of HABs to Iowans; (2) support the evaluation and cost-benefit analysis of Iowa Nutrient Reduction Strategy and other conservation programs in Iowa; and (3) provide information for better designing water quality improvement policies in both regional and state scales.
Denitrification in Agricultural Depressions by Nitrate Isotope Analysis
Iowa’s agricultural lands are among the most productive in the world, but they are also a large source of nitrate (NO3-)pollution. Ideally, NO3-is incorporated into crop tissues which are removed through harvest. NO3-which is not utilized by crops, or is returned to the soil through mineralization, is primarily lost through leaching and denitrification (Libra et al., 2004). The highest rates of NO3-leaching in Iowa are found in the poorly drained Des Moines Lobe (DML), where extensive tile drainage is thought to promote leaching to streams (Jones et al., 2017). However, wet soil conditions also promote denitrification, where in the absence of oxygen, soil microbes reduce NO3-to gaseous forms, primarily nitrous oxide (N2O) and dinitrogen gas (N2) (Hall et al., in press). Soil water content in the DML is mediated by the presence of landscape depressions (former prairie pothole wetlands), where both infiltration and N2O production may exceed surrounding uplands (N. Lawrence, unpublished). Quantifying how much NO3-is removed through denitrification versus lost through leaching is critical to understanding the role of landscape depressions as a source and sink of NO3-at the landscape level and providing insight into how targeted management of depressions might address NO3-loads. Here, we propose to apply a cutting-edge method—analysis of the natural-abundance isotope composition of NO3-—to address the role of within-field denitrification in attenuating agricultural NO3-loads.
Quantifying Differential Sorption and Biodegradation of Pharmaceuticals in a Wastewater Effluent-Dominated Stream in Iowa
Wastewater effluent contains a complex mixture of biologically active chemicals, in-cludingpharmaceuticals. Many pharmaceuticals have demonstrated deleterious effects to aquatic organisms including endocrine disruption, causing intersex characteristics,and reduced fecundity. These biological impacts can be magnified under low-flow conditions where wastewater effluent substantially contributes to the streamflow. Effluent-dominated streamflow conditions are becom-ing more common in temperate regionssuch as Iowa and are expected to increase due to climate change and population shifts.Current understanding of pharmaceuticals in the aquatic environ-ment does not adequately account for how pharmaceutical mixtures evolve spatiotemporally, or how pharmaceutical mixture composition relates to biological effects. Natural attenuation pro-cesses can either reduce or increase the toxicity of pharmaceuticals towards the aquatic species. Thereisa critical needtounderstand the underlying attenuation mechanismsincluding sorption and biotransformation to better predict the fate, transformation,and associated biological impacts of pharmaceutical mixtures. This research will help protect ecosystem health in freshwater re-sources in Iowa and inform stakeholder decisions such as wastewater treatment plant design, op-eration,and upgrade.
Determining the Effects of Co-Nutrient Availability on Harmful Algal Blooms Across Varying Lake Types
Harmful algal blooms caused by cyanobacteria (cyanoHABs) are a serious water quality problem in Iowa’s lakes. The presence of cyanobacterial toxins in Iowa’s lakes can threaten human health and increase economic loss. The proposed study will investigate how co-nutrient limitations, such as nitrogen and iron, combine with factors such as temperature and dissolved oxygento fuelcyanoHAB growth and toxin release across different lake types in Iowa. In general, artificiallakes tend to havelowernutrients, but earlier studies found nutrient conditionsto be higher in those surrounded by agricultural land use. We hypothesize that cyanoHAB intensityis higher in Iowa’s artificial lakes (e.g. reservoirs, impoundments) due to greater surface runoff carrying agriculturally-derived nutrients (N, P). We will test this hypothesis by measuring nutrients, including iron (Fe), which is generally not measured. We willlook for correlates between individual nutrients or nutrient ratios and/or physical conditions with phytoplankton biomass and toxin presence. This approach will help reveal larger landscape-scale trends distinguishing the susceptibility of artificial vs. natural lakes to cyanoHAB formation and toxin release. Findings from this study will help facilitate environmental risk management and develop mitigation strategies to reduce human and animal health risk.
Developing Methods to Measure Internal Phosphorus Loading in Iowa Lakes
Harmful algal blooms (HABs) present public health challenges for communities in Iowa and around the globe. These blooms are most closely associated with in-lake phosphorus availability. Management strategies to prevent and mitigate HABs typically focus on watershed sources of phosphorus; however, lakebed sediments also represent a pool of phosphorus that may reenter the water column and fuel HABs. In many systems, this internal phosphorus loading can maintain high, in-lake phosphorus concentrations, even if external nutrient inputs are reduced.It is known that a variable suite of chemical, physical, and biological mechanisms drives internal P loading; however, these control points are poorly understoodand quantified in shallow lakes. The objectives of this research are to (1) quantify the magnitude of gross internal phosphorus loading in shallowlakes, including variation within and among lakes; (2) identify sources of variation in internal phosphorusloading within and among lakes; and (3) evaluate the relative influences of chemical conditions and disturbance on sediment phosphorus loads. In order to meet the proposed objectives, we will build a sediment core incubation system and use it to measure gross internal phosphorus loading on cores from seven study lakes in northwestern Iowa. Replicate cores will be incubated under different oxygen and disturbance treatments to evaluate interactions among hypothesized drivers of internal loading. The results of this research will offer a quantitative understanding of internal phosphorus loading in shallowlakes. Thisis critical knowledge for the prediction and prevention of HABs.This project will additionally enhance our understanding of shallow lake biogeochemistry, offer verified methods to measure sediment phosphorus fluxes, and provide managers with another tool for lake restoration planning and evaluation.
The Economic Benefits of Mitigating Harmful Algal Blooms in Iowa
In the United States, one-third of all agricultural output depends on pollinators. Unfortunately, the populations of native and managed pollinators such as honeybees and monarch butterflies have experienced significant declines over the past decade. The loss of proper habitat that provides pollen and nectar along with changes in agriculture production practices, the use of broad-spectrum pesticides, and urbanization are among the main culprits for these declining trends. In response, many governmental and non-profit efforts have been devoted to enhance pollinator habitats. In particular, the USDA Conservation Reserve Program (CRP) Pollinator Habitat Initiative provides farmers and landowners with monetary incentives to plant legume-rich forage or diverse wildflower plantings. In 2015, Iowa launched the “Monarch Highway” (I-35) to create a multi-state partnership to help promote monarch habitats, such as milkweed plants.Increasing pollinator habitats in agricultural areas is particularly relevant for the IWC because native plants that make up monarch and pollinator habitat like milkweed plants, wildflowers, and bunch grasses, have deep root systems that can reach several feet into the ground. These plants provide food and shelter for many wildlife species, including monarchs, while also helping to slow the flow of runoff and prevent contaminants from reaching our waterways. Despite these connections, few studies examine the potential co-benefits that stem from efforts to enhance pollinator habitat, which may produce water quality benefits in addition to wildlife/pollinator benefits. We propose building on the IWC-funded year 1 survey on the economic value of harmful algal bloom reduction to conduct a general public survey on the willingness to pay (WTP) for pollinator conservation and the tradeoff between water quality benefits and pollinator benefits through conservation efforts to protect and enhance habitats for monarch butterflies. In particular, we propose conducting a mixed-mode survey of 3,000 households in Iowa and neighboring states along the monarch butterfly migration path in spring/summer 2020. A key component of the survey is a set of choice experiments that mimic possible policy scenarios that vary in the acres of conservation practices, possible improvements in surface and drinking water quality, and the population and health of key pollinators like monarch butterflies. In particular, we explore how Midwest residents’ valuation varies when their hypothetical monetary contribution helps with the upstream restoration of milkweed habitat, or donation to a general pollinator protection NGO. We will also gather valuable information about residents’ knowledge of various pollinators such as butterflies, habitat species such as milkweed, and their understanding of the connections between water quality and pollinator benefits. Understanding how Midwest especially Iowa residents value pollinator conservation is an important step towards a better understanding of the co-benefits associated with conservation practices that enhance water quality, benefits that can be missed when valuation studies focus on water quality benefits alone. The survey can also examine how the exposure to monarch butterflies would affect the valuations of pollinator conservation among residents along the migration path, and how Iowa residents’ views and valuations differ from neighboring states.
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Review the 2021 policy brief based on these projects here.
Measuring Impacts of Lake Management Practices on Harmful Algal Blooms using Continuous Monitoring at the Iowa Great Lakes
The nutrient dynamics in eutrophic shallow lakes is complicated by a number of external and in-ternal ecosystem factorsthat control the timing and rates of nutrient availability. Depending on these dynamics,abundant dense-rooted aquaticplants or algal blooms commonlyform. High-value recreational lakes, such as those that comprisethe Iowa Great Lakes, experienceadditional pres-suresdue to invasive speciesand desire to ensure clear,open water conditionsfor recreational purposes.The lakes also serve as a critical drinking water source for local communities. Manage-ment of rooted aquatic plants, includingthe amount andtiming of removal can affect internal re-cycling of nutrients, which may result inconditionsamenable for development of algal blooms.Theseblooms can consist of cyanobacteria (i.e., blue-green algae),or what have become com-monly known as harmful algal blooms (HABs).During their life cycle,HABs lead to unpleasant conditions including blue-green scums on the water surface, and under someconditions HABs release toxins into the water,which present a health risk.With this researchwe propose to addressthe following question: “To what degree doin-lake management activities,designed to improve water quality and recreation at the Iowa Great Lakes,affect the occurrence of algal blooms, particularly harm-ful algal blooms due to cyanobacteria?”Recorded trends of HABs are rising in Iowa and are a major concern due to their impacts on drink-ing water supplies and human health, on recreation, and due to the danger to livestock, pets, and wildlife. A number of Iowa lakes regularly experience HABs. Some lakes,such as Green Valley Lake,experience chronic HABs throughout the summer, while others (e.g.,Lake MacBrideand Big SpiritLake)only occasionally experience blooms.Predicting when andwhere HABs will form is still poorly understood. Nevertheless, withadvances in real-time continuous monitoring, as well as recent investments in water quality monitoring buoys by the Iowa DNR and Iowa Lakeside Laboratoryinstalled on two of the Iowa Great Lakes, there is now an opportunity to investigate how management practices intended to control water quality affect the conditionsthat result in HABs. In particular, internal recycling of nutrients may be affectedby management of invasive rooted aquatic plants, such as curly-leaf pondweed. Investigating nutrient release rates from lake sediments along with trackingthe timing and extent of management activities will provide critical data to better understand the connections between lake water quality management and HABs.Ex-treme weather resulting in sediment resuspension and release of phosphorus from lake sediments may also be a factor in the formationof HABs.
Read full research findings here.
Hydro-NPOSS: A Non-Proprietary Open-Source Software for Hydrologic Data Visualization and Model Evaluation
Emerging techniques and data sources such as satellite remote sensing platforms and field observation networks have brought an unprecedented opportunity for the hydrologic community to better understand hydrologic cycle. At the same time, it has introduced challenges requiring effective tools and techniques for dissemination, visualization and analysis of the hydrologic data. Several open-source software solutions have been developed for hydrologic data visualization and analysis. Unlike their commercial counterparts, open-source software for web applications can benefit from developer contributions, user feedbacks, and further improvement. However, in most cases, the current solutions for hydrologic data have multiple dependencies on third-party software and programming languages which makes them cumbersome and time-consuming to deploy, maintain, and extend. To overcome these hurdles, we developed a non-proprietary open-source software (NPOSS) that allows users to visualize and analyze multivariate space-time hydrologic data that we call Hydro-NPOSS. Hydro-NPOSS leverages the concept of three-dimensional data cubes that allow users to query data in space, time, and variable dimension(s) which does not require a database system. Thereby, users can define data sources from local file systems and/or external data sources (e.g. online data services). This capability makes Hydro-NPOSS a flexible and portable solution where users can publish their hydrologic datasets in Open Data journals or as companion to their publications. Moreover, Hydro-NPOSS is an easy-to-deploy and interactive web solution for data visualizations where it can be used for visualizing time-series and geospatial datawith least effort and user expertise in web application development.