Stream Nitrate Load Monitoring for Watershed Scale Assessment of Edge-of-Field Practices

Water quality in Alleman Creek, a small watershed in Iowa,
will be monitored through stream nitrate sampling and streamflow monitoring. Nearly all
subsurface drainage tile outlets in this watershed were treated with an edge-of-field
nitrogen reduction practice (saturated buffer or denitrifying bioreactor) as part of the first
Polk County Batch and Build Project. This project will assess the effectiveness of these
edge-of-field practices at scale by quantifying the reduction in nitrogen mass leaving the
watershed. This watershed assessment will be contextualized with nitrate mass reduction
monitoring of three individual saturated buffers in the watershed. This research will
provide valuable empirical data on the effectiveness of edge-of-field water quality
practices at a larger scale as widespread implementation of these practices accelerates to
meet water quality goals.

FloodRSS: Flood Resilience Support System for Participatory Community Action

Floods impact 2.2 billion people globally, and their occurrence displays an alarming increase
compared to other natural disasters. The State of Iowa follows this ascending trend, with flood-
presidential disaster declarations occurring almost every other year for the last 30 years. The
ever-growing flood threats continue to be tackled with piece-meal, sectoral mitigation
approaches that are trickled down to communities through top-down, limited-efficiency solutions
that disproportionally affect the socially vulnerable populations in rural and urban communities.
While considerable scientific and technological progress is increasingly available for many flood
mitigation efforts, their on-the-ground impacts are impeded, among other causes, by the limited
availability of tools to rapidly turn the expanding data into accessible and actionable knowledge
for flood mitigation. Changing the current situation requires a “system of systems” (SoS)
approach whereby the underlying hydrologic processes leading to floods are closely linked with
the watershed-level socio-economic functions through efficient collaboration tools to ensure
community involvement in the co-production of the mitigation plans with attention to socio-
environmental justice principles. Currently, there is no unified vision on the architecture,
components, and technologies for a generic flood mitigation and resilience support system.
The aim of the proposed research is to develop a prototype web-based mitigation platform,
Flood Resilience Support System (FloodRSS), for participatory community action where the
multi-disciplinary legacy datasets and incoming data streams are organized, stored, and analyzed
as a “big-data” case driven by emerging concepts in flood vulnerability and resilience. Our
proposal responds to the priority on “water related hazard and society” by linking flood
underlying hydrologic processes with socio-economic aspects within a generic and modular
cyberinfrastructure that can be iteratively enhanced with new developments as they occur.

Using Optical Brighteners as Proxies for Probing Waste in Surface Water

Optical brighteners—or fluorescent whitening compounds (FWCs)—absorb light
in the ultraviolet and violet region of the electromagnetic spectrum, and reemit light by a process
known as fluorescence in a lower-energy region of the spectrum, namely in the blue region
(typically 420-470 nm). These additives are often used to enhance the appearance of the coloring
of fabrics and papers, causing a “whitening” effect; they make intrinsically yellow or orange
materials look less so, by compensating the deficit in blue and purple light reflected by the material,
with the blue and purple optical emission of the fluorophore [1-9]. Because these are synthetic
compounds and, consequently, not naturally occurring, they make excellent markers for detecting
leakage of wastewater into surface water as they are introduced into sewage from the detergents
used in clothes washing. We propose to characterize commercially available optical brighteners
that are used predominantly in laundry detergents to determine the uniqueness of their spectral
signatures and to ensure that there is no spectral overlap with spectral signatures from other waste
or from naturally occurring substances. We also propose to determine the lifetimes of the optical
brighteners in the presence of oxygen, light, microbes, and surface water as such environments
may contribute to their partial decomposition, rendering them potentially useless as analytical
probes yet still deleterious from a public health perspective. Funding for this proposal will, in
addition to ensuring the outcomes noted above, also continue the training of promising
undergraduate students, enable the submission of a larger federally-funded grant proposal, and
potentially permit the patenting and licensing of new detection technology (with which we have
experience, as noted on our vita and as indicated by our RD100 award).

Treatment Impacts on Per- and Polyfluoroalkyl Substances (PFAS) Discharge in Wet- Weather Flows

Per- and Polyfluoroalkyl Substances (PFAS) are a class of over 6,000 persistent,
bioaccumulative, mobile, and toxic environmental contaminants that are ubiquitous in
wastewater and stormwater. PFAS exposure is linked to adverse human health outcomes and
lethal and sublethal toxicity in aquatic species. PFAS discharges in wastewater effluent draw
increasing scrutiny from states, including Iowa, and federal regulatory rule making is underway.
The best-studied and most frequently regulated PFAS are perfluoroalkyl acids (PFAAs). PFAAs
are also the terminal transformation products of many precursor PFAS with more complex head
groups. Wastewater treatment processes can transform many precursor species into PFAAs;
however, precursor species are less likely to be researched, monitored, or regulated than their
terminal transformation products.
We propose to investigate whether shorter hydraulic retention times during wastewater treatment
will result in less precursor transformation and therefore a greater discharge of PFAS which are
“invisible” to standard measurement protocols. Proper accounting of often-unmeasured precursor
PFAS—which may contribute to aquatic toxicity and can transform into terminal PFAAs in the
environment—will provide a more comprehensive understanding of PFAS discharge to
environmental waters from stormwater and wastewater. This improved understanding will enable
more informed treatment design and the establishment of effective and equitable regulations.

Probing Groundwater-Surface Water Interactions as a Driver of Complex Mixture Evolution in an Effluent-Impacted Stream in Iowa

Climate change and urbanization are increasing the influence of municipal wastewater effluent on
receiving waters, making wastewater effluent-dominated streams common worldwide, including
in temperate regions. This phenomenon increases loading of contaminants of emerging concern
(CECs) including pharmaceuticals, personal care products, pesticides, and industrial chemicals
from wastewater treatment plants (WWTPs) to drinking water supplies (i.e., de facto reuse) and
ecological systems. Treated effluent from WWTPs releases CEC mixtures that vary
spatiotemporally, which generate complex exposure conditions for biota and potential for
deleterious interactive effects (e.g., drug-drug interactions). When individual CECs present in
mixtures are removed from the aqueous phase via sorption or degrade from the stream at different
rates (i.e., differential attenuation), exposure conditions for biota change. Attenuation rates of
CECs we measured in the field are much greater than those in batch degradation tests—suggesting
other relevant stream processes. Currently, we do not fully understand the role of groundwater-
surface water exchange on complex mixture evolution. There is a critical need to evaluate the role
of groundwater-surface water exchange as a driver of complex mixture evolution using next-
generation high-resolution non-target analytical approaches to quantify CEC spatiotemporal

Identify causal pathways of how household flood recovery measures lead to the reduction of unmet social needs

The frequency of catastrophic flood events, amplified by climate change has increased
substantially in US Midwest (Neri et al., 2019; Reed et al., 2020). Flooding causes major
economic and social damage in the region. Because community vulnerabilities increase flood
impacts, vulnerability reduction is a crucial part of flood risk management. Many household
flood recovery projects often fail to address pre-existing community vulnerability, and in many
places the measurement of such reduction (if any) is difficult to identify.
The objective of the project is to determine how flood recovery measures facilitate the reduction
of unmet needs in a flood affected community. These unmet needs can be social, physical, health
or economic. The case study is based on two research questions: RQ1) What are the unmet social
needs of the flood exposed community? and RQ2) To what extent do flood mitigation measures
address unmet social needs? The study area is the City of Dubuque, which provided data
required for this project

Denitrification potential in floodplain forests: Investigating water quality improvements to reduce negative impacts in downstream communities

The US Cornbelt is a leading global producer of intensively managed, row-crop corn and
soybeans – yet, the agricultural production of these commodities is often linked to challenges
associated with nonpoint source nutrient pollution that negatively impacts water quality and
highly altered hydrology that negatively impacts surface water discharge. Excess nitrogen and
phosphorus in surface water can have regional and local impacts on aquatic ecosystems,
recreational opportunities, livelihoods, and human health. Altered hydrology can lead to excess
discharge, resulting in extreme flood events. While these challenges affect many downstream
regional and local communities, underrepresented, underserved communities and communities of
color are often disproportionately impacted by these negative environmental externalities.
Floodplain management offers a unique opportunity to address challenges related to water
quality and water quantity to reduce downstream impacts. Floodplain forests represent a
potentially powerful water quality and quantity conservation practice, as rigid upright stems and
associated downed woody material and understory vegetation act to reduce flood flow velocities
and encourage water retention and infiltration. Deposition of sediment and associated
phosphorus are associated with reduced flood velocities, and deposition acts to transfer these
potential pollutants into long-term floodplain storage. Often overlooked is the ability of
floodplain forests to address riverine nitrogen loading. Through a combination of floodwater
retention, raised water tables, and sediment and organic matter deposition, floodplain forests
create zones of nitrate removal by encouraging processes such as denitrification. In addition to
larger water retention sites often associated with woody floodplain vegetation (e.g., oxbows),
individual trees and downed woody material provide abundant water retention microsites
through tree windthrow (e.g., pit and mound microtopography) and localized scour. Although
floodplain forests represent potentially significant nitrate sinks, research that quantifies nitrogen
removal within these areas is rare – especially in the agricultural Midwest. In addition, studies
that seek to link water quality and quantity impact with current forest species composition,
structure, and condition, and provide management recommendations to maximize water quality
and quantity return, are exceptionally rare.
The primary objectives of this project are to: 1.) estimate riverine nitrogen removal performance
of individual floodplain forest sites along major Iowa rivers, 2.) combine floodplain forest water
quality and quantity data with forest stand inventory to estimate watershed-scale impacts of
floodplain forests, and 4.) increase awareness and value of floodplain forest systems within
impacted, underserved downstream communities. To meet these objectives, we will employ a
combination of in-field monitoring and inventory, hydraulic floodplain modeling, a conservation
planning tool, and extension efforts. The results and outcomes from this project will be used to
create floodplain forest management recommendations, and maximize water quality (i.e.,
nitrogen) and flood mitigation returns for underserved downstream communities. Field data will
also be coupled with GIS-based modeling used by co-PI Zimmerman to quantify landscape-level
outcomes associated with floodplain forest management and key opportunities to maximize
restoration benefits. Associated extension programming seeks to increase awareness of
floodplain forest value to underserved audiences, and sustain management through promotion of
natural resource careers (e.g., forestry) within underserved downstream communities.

Environmental Justice for All: Nutrient Impacts on Lake-Based Recreation and Tourism by Rural and Socially Disadvantaged Iowans

Over the past 18 years, nitrogen pollution flowing out of Iowa to the Gulf of Mexico has grown by close to 50% and contributed 29% of the total nitrogen headed to the Gulf from the Mississippi-Atchafalaya River basin. Increased nutrients in Iowa’s water deteriorates water quality and can lead to toxic algal blooms that can both decrease the oxygen fish and other aquatic life need to survive and can cause illness in humans through contact during recreational activities. In addition, in the presence of excess nutrients, potable water is more likely to be contaminated and cause disproportionate burdens and health risks for low-income and minority communities. An increase in the population impacted by nutrient issues in Iowa sparks concerns about broader socioeconomic disparities in nutrient pollution exposure. More studies are needed to understand the nutrient impacts on social wellbeing for all Iowans.

This 12-month project aims to understand nutrient impacts via the lens of local recreation and tourism as well as the economic impact of water quality improvement on rural and lower-income communities. Specifically, we have three objectives. First, focusing on lower-income and underrepresented households and building on nearly two decades of historical Iowa Lakes Survey work (2002–2019), we will examine how water quality influences participation in lake recreation activities and the roles of water quality perception and recreation equipment ownership on households’ recreation decisions. Second, we will supplement the forthcoming Iowa DNR 2020 Iowa Lakes Survey to include more household samples from rural and lower-income communities to counter the underrepresentation of these communities in previous surveys. The COVID-19 pandemic also provides us an opportunity to investigate if rural and lower-income communities respond differently to this change in 2020. Third, we will conduct a series of IMPLAN analyses to quantify the economic impacts of current recreation and tourism activities on local economies and project how these economic impacts change under different nutrient-driven water quality scenarios.


Understanding the Impacts of Coronavirus-related Reduction in Aerosols and Pollution on Precipitation and Discharge across Iowa

Among the many impacts of the COVID-19, the pandemic has led to improved air quality conditions in the countries under quarantine. Satellite-based maps highlight a remarkable reduction in aerosol and air pollution due to the shutdown of industries and very limited traffic in China and other Asian countries between late January and March 2020. Similarly, many areas across the United States have also experienced a large reduction in air pollution due to the lockdown in response to COVID-19. Meanwhile, large areas of the central United States, particularly within the Missouri River Basin, received less precipitation than normal during February-April 2020. Is it possible that the observed reduction in precipitation was driven by the reduced aerosols due to the coronavirus? If so, how much of these changes can be attributed to the pandemic and what does it mean in terms of discharge?

Our hypothesis is that the local aerosol reduction led to a detectable change in precipitation and discharge across the central United State and Iowa, and that these effects were either magnified or reduced depending on the magnitude of the long-range transport of particles. Therefore, the goal of this proposal is to evaluate how much of an impact this abrupt reduction in local and remote aerosols played during the past winter/spring in terms of precipitation and discharge, and to determine the physical mechanisms at play.

The research methodologies build on analytical tools and data sets with which the research team has extensive experience, and will be developed further to address the role of the reduction in aerosols due to COVID-19 in relation to the reduced precipitation and discharge across the central United States broadly, and Iowa in particular.

We will use the Weather Research and Forecasting (WRF) model coupled with Chemistry version 3.8.1 (WRF-Chem), and force it with the North American Regional Reanalysis (NARR) data and the near real-time Whole Atmosphere Community Climate Model (WACCM) outputs. We propose to design four experiments to isolate the relative contribution of the aerosols: Control (CTRL), Business-as-usual (BAU), NoTrans, and NoLocal experiments. In these runs, the circulation (e.g., zonal and meridional winds, geopotential height) is the same but they have different settings for transported and local aerosols. By comparing the four experiments, we can assess the relative roles of aerosols in forcing the observed changes in precipitation and discharge during February-April 2020. In addition to precipitation and discharge, the proposed experiments will produce outputs (e.g., temperature, humidity, ultraviolet radiation, ozone) which are important to diagnose the environmental conditions for the survival and spread of COVID-19.

The proposed research will enhance our knowledge of the role of local and remote aerosols on precipitation and discharge across the central United States, with a special focus on Iowa. Given the extreme reduction in aerosols due to the pandemic, our findings will have both short- and long-term impacts. In the short term, insights gained from this research can provide information in terms of preparation for the upcoming fall and winter from the perspective of water resources and emergency management. In the long term, our work will provide basic information on the potential impacts of different mitigation efforts aimed at reducing anthropogenic aerosols on precipitation across the central U.S.

The results and data from this project will be made available to federal and state agencies. Moreover, this information will be readily available to local stakeholders and users for their own use. The research team will leverage the tools and expertise provided by the Iowa Flood Center (IFC) to make the results of the proposed work relevant and immediately and directly available to agencies and to the general public. Moreover, the dissemination of the results will be facilitated by means of outreach activities through the IFC and the Iowa Water Center.

Catchment-scale hydrologic modeling of urban residential stormwater best management practices (BMPs)

The combined effects of urbanization and projected climate changes are expected to increase the already negative effects of urban areas on surface water resources. Increased runoff volumes, flow rates, and pollutant loads due to impervious surfaces will likely be exacerbated by increased intensity and duration of storm events, leading to degraded aquatic ecosystems and impaired water quality. In Cedar Falls, Iowa (the location of our project study sites) segments of Dry Run Creek which feed into the Cedar River have both biological and bacterial impairments. New approaches to stormwater management known as green infrastructure and stormwater best management practices (BMPs) are designed to restore the natural hydrologic cycle, increasing infiltration, reducing runoff volumes and rates, and trapping/filtering pollutants in soil. These practices have the potential to improve water quality and the ecological integrity of aquatic systems, but additional research is needed to quantify these effects. Extensive monitoring and modeling of distributed small-scale BMPs is crucial to understanding how these practices can reduce the impacts of stormwater on surface water resources, as well as to improving the long-term resiliency of stormwater management infrastructure to adapt to future climate changes. Additional empirical data for stormwater runoff quantity and quality are also crucial to the development of realistic and reliable urban hydrologic simulations. Several parameters within hydrological models, especially those used to assess and predict water quality, require extensive monitoring for robust model calibration. Subsequent model validation is also best performed using data independent of that used in the calibration process. Due to the time- and cost-intensive nature of long-term monitoring and sampling studies, many hydrologic models are not based on site-specific flow or water quality data, leading to high levels of uncertainty about whether they represent “real world” scenarios. This proposal seeks support to extend efforts to monitor stormwater runoff quantity and quality from two “paired” residential neighborhoods in Cedar Falls. The extended period of monitoring proposed here (from two years of previous monitoring to three years) will provide the data needed for parameterization and robust calibration and validation of hydrologic and water quality models. This will also allow for comparison to and closer replication of a previous five-year study conducted in the Easter Lake Watershed in Des Moines. The specific objectives of this study of two residential watersheds in the Dry Run Creek Watershed are to: 1) Monitor stormwater quantity and quality during storm events for one additional year; 2) Collate independent data sets to parameterize, calibrate and validate water quantity and quality models for both watersheds; 3) Characterize stormwater BMP effects on runoff volume and water quality parameters; and 4) Predict possible hydrologic outcomes of varying levels of BMP adoption across spatial and temporal scales, including the effects of climate variability over time. The results of this study will allow a range of hydrologic and water quality outcomes to be quantified and simulated, and will ascertain the levels of BMP adoption necessary to achieve water quality goals. Additionally, results of climate change simulations can be used to provide long-term hydrologic predictions and to support urban resiliency planning.