ABSTRACT. While microplastics (MP) have been found in aquatic ecosystems around the world, the understanding of drivers and controls of their occurrence and distribution have yet to be determined. In particular, their fate and transport in river catchments are still poorly understood. We here identified MP concentrations at fifteen locations across the Neuse River Basin in North Carolina, USA. MPs >335 µm were found in all the stream water samples with concentrations ranging from 0.02 to 221 particles per cubic meter (p m-3) with a median of 0.44 p m-3. The highest concentrations were observed in urban streams and there was a significant correlation between streamflow and MP concentration in the most urbanized locations. Fourier Transform Infrared (FTIR) analysis indicated that for MPs >335 µm the three most common plastic types were polyethylene (37%), polypropylene (18%), and polystyrene (15%). A wide range of plastic types, plastic additives, resins, and copolymers were identified. We estimate MP (>335 µm) loading from the Neuse River watershed to be 670 million particles per year. Results will be related to common construction materials and how we can limit the plastic pollution generated from our ecological engineering projects.

ABSTRACT. Diverting food waste from landfills to anaerobic digestion (AD) can reduce methane (CH4) emissions and enable recovery of energy and nutrients in the form of biogas and digestate soil amendments. Recognition of these co-benefits has prompted recent food waste diversion initiatives across the US, but many food waste streams are not suitable for AD because they are mixed with plastic packaging (e.g., spoiled pre-consumer, imperfectly source-separated post-consumer, etc.). Mechanical depackaging systems separate residual packaging from organics, enabling the diversion of these contaminated food waste streams to AD. However, the possibility of imperfect mechanical separation has raised concerns that soil amendments derived from depackaged food waste may be a source of microplastics in the environment. To better understand these potential tradeoffs, we evaluated biochemical methane potential (BMP) and other key AD parameters (TS, TVS, COD, N, P, S, pH) as well as plastic (>0.5 mm) content of depackaged pre-consumer ice cream pints, depackaged post-consumer food scraps, and digestate derived in part from the depackaged ice cream pints. Depackaged ice cream pints had greater BMP than depackaged food scraps, at 453 ± 52 and 435 ± 37 NmL CH4 g VS-1, respectively. Our preliminary results indicate that depackaged ice cream pints had ~3 times the plastic content of depackaged food scraps on average, at 0.199 ± 0.144% and 0.070 ± 0.052% w/w TS, respectively. Average plastic content of the digestate was 0.016 ± 0.017% w/w TS. These results indicate that depackaged food waste can provide a valuable substrate for AD, however, plastic contamination in the resultant digestate, while low on a percent mass basis, is a drawback. More research is needed to compare microplastic content across other food waste management strategies and soil amendments.

ABSTRACT. The study bioprocessing of food waste (FW) to produce volatile fatty acids (VFA), bioenergy (methane/hydrogen), and bioplastics in a closed-loop approach. Anaerobic dark fermenters (ADF) and micro-aerobic dark fermenters (MADF) were created for FW processing to produce volatile fatty acids (VFA), which were used in bioplastics production. The ADF and MADF reactors were comparatively tested to understand the effect of fermenting FW and high salinity food waste (HSFW) using thermohydrolysis pretreatment (120 and 150°C for 15/30 min), pH adjustment (7, 10, and unadjusted), inoculum to substrate ratio (ISR), residence time (3, 6, 9 and 12 days), and temperature (mesophilic: 35°C and thermophilic: 55°C) to maximum FW conversion into VFAs. The highest VFA concentration achieved was 30.43 g/L using the MADF reactor and 30.21 g/L with the ADF reactor with an ISR of 1:4 at 55°C with a 12-day residence time. The MADF inoculum source had the most VFA content as acetic acid (27.58 g/L), followed by butyric (2.08 g/L), valeric (0.37 g/L), propionic (0.36 g/L), and iso-valeric (0.22 g/L). The conditions recommended for VFA production include blending of FW and HSFW as substrate with the microaerobic DF content as a seed with ISR of 1:4, operating at thermophilic temperature (55°C) with 6-day residence time and pH adjustment to 7.0 using KOH/NaOH and no thermohydrolysis pretreatment utilized. The produced VFAs were filtered (0.22 µm) to separate the solids and liquids, with the solid residuals used for methane production via anaerobic digestion and the liquid with the VFAs for bioplastic production using the bacteria Haloferax mediterranei (HM). This integrated approach improves the FW bioprocessing and provides complete carbon conversion into bioproducts, thus guiding a sustainable biobased economy. Techno-economic analyses (TEA) and life cycle assessments (LCA) are being used to understand the economics and process upscaling to create a food waste biorefinery system.

ABSTRACT. Ecosystem restoration has emerged into the mainstream as one of the central tools for society to forestall the global crises of biodiversity loss and the adverse effects of climate change. Nationally, Nature Based Solutions (NBS) and Engineering with Nature (EWN) have been written into policy and backed with billions of dollars through the Inflation Reduction Act and Bipartisan Infrastructure Law. As the wave of federal money lifts the ships of the ecological engineering community, its incumbent upon us to ensure that each investment in the ecosystem is yielding a positive return. The potential benefits associated with NBS are well defined, with ecosystem services often serving as a foundation for articulating a projects’ goals. But the anticipated benefits of a project are only one part of the ledger and are not, in and of themselves, enough to gage the value of an investment. The ecological engineer must also consider the natural capital costs associated with building an NBS project during design, and work to minimize impacts. The regeneration principle is defined as maximizing the return of ecological processes, biodiversity, and community well-being to natural capital invested. To operationalize the regeneration principle, a preliminary framework is proposed, with NBS project examples, to provide practical guidance and provoke discussion for ecological engineers.

ABSTRACT. Beaver dams can create flooding that poses a threat to human infrastructure, often resulting in their removal from an area. In an attempt to coexist with these beavers, deception and exclusion devices, or “beaver baffles,” may be installed to lower water levels without disrupting beaver activity. Little is known, however, about how these devices influence biogeochemical ecosystem services of beaver wetlands, including nitrate (NO3-) removal and carbon cycling dynamics. This study compared the rates of nitrate removal and carbon gas emissions (e.g. CO2 and CH4) between baffled and control beaver dams to evaluate the effects of baffles on these systems. We hypothesized that beaver impounded wetlands utilizing deception and exclusion management techniques would (1) have lower levels of nitrate removal (2) produce higher average carbon fluxes when compared to their natural, unmanaged counterparts. We found that, while NO3- removal was not significantly different between sites, baffled sites exhibited a positive relationship between increased downstream NO3- and discharge rates (p = 0.003, R2 = 0.633). Baffled sites also generated higher carbon dioxide (CO2) emissions (p = 0.003), though their methane (CH4) emissions were roughly similar to unmanaged sites (p = 0.296). These results suggest that implementation of baffles decrease stream NO3- removal during high discharge events and may increase atmospheric carbon mineralization in beaver impounded wetlands.

ABSTRACT. Increasing urbanization has profound impacts on freshwater ecosystems such as changing hydrology, water pollution and degraded biological habitats. River and stream restoration has become a popular management strategy for improving the physiochemical and ecological conditions of degraded urban streams in the United States. However, restoration in urban streams is both expensive and difficult because of the limits of many factors such as land ownership and urban infrastructure. To maximize the benefits of stream restoration practices with limited resources, we need to identify degraded streams with the highest priority for restoration. Previous studies developed various stream restoration prioritization tools. These tools prioritized streams for restoration based on various metrics that were developed to assess stream health (e.g. lower scores imply higher restoration priority). In this research, we propose to prioritize streams for restoration from a different perspective—stream restoration potential. Greater restoration potential indicates that stream health can be improved to a higher level (e.g. poor to fair, fair to good) with less restoration effort. From this perspective, we developed a stream restoration prioritization tool to identify streams with the greatest restoration potential in the Southeast Piedmont, a region that has experienced rapid urbanization, by using structural equation modeling (SEM). The USGS Southeast Stream Quality Assessment (SESQA) dataset was used for model development and the macroinvertebrate multi-metric index (MMI) was used to measure stream health level. Moreover, we developed a weighted metric to quantify the model predicted efforts to restore a stream, which can help managers to rank the priority of streams. Finally, by applying the tool to 75 streams in the Southeast Piedmont, we identified degraded streams with the greatest restoration potential and demonstrated the usefulness of SEM in combination with the developed weighted metric in prioritizing streams for restoration and proposing potential restoration strategies.

ABSTRACT. The Suwannee River Water Management District (District) applies environmental flow analyses to develop minimum flows and levels (MFLs) for priority waterbodies. These MFLs set the limit at which further surface and groundwater withdrawals would be significantly harmful to the water resources or ecology of the area. Over the past two decades, the District has established MFLs for a majority of its rivers and is currently focused on developing MFLs for the Upper and Middle Suwannee River segments and several priority springs. These river and spring MFLs are based on a suite of environmental flow analyses that relate changes in flows or levels to relevant recreational and ecological metrics, which often involves use of hydrologic and ecological simulation modeling. Examples include assessing how changes in flows affect instream fish and invertebrate habitat area, the frequency of floodplain wetland inundation, and the amount of time that boats can safely navigate shoals. While the District utilizes several analytical methods that were initially developed by other water management districts, we are working to refine these methods and develop new methods with particular focus on springs. In cases where MFLs are not being met, the District is required to develop recovery strategies that implement conservation measures, regulations, and projects to increase flows or levels to meet the MFLs. The Lower Santa Fe and Ichetucknee Rivers and associated priority springs are the focus of an ongoing regional recovery strategy. Several of these project concepts involve utilizing ecological engineering principles, particularly constructed treatment wetlands and alternative silviculture management to recharge the Floridan aquifer and restore springs flows. This presentation will review environmental flow analyses that the District applies to rivers and springs and discuss ongoing efforts to develop strategies that recover flows where needed.

ABSTRACT. Wetland structure and function are driven largely by hydrology. Successful wetland restoration and conservation therefore requires an understanding of hydrologic targets and thresholds. Measuring hydrology in reference wetlands is often critical for setting restoration benchmarks, and previous literature has defined general hydrologic characteristics, such as hydroperiod, for utilization as targets. However, it remains unclear how comparable wetland hydrology is within and across different reference wetland types--and what drives these hydrologic similarities and differences, especially across a broader set of ecohydrological indicators. To fill this gap, we used long-term water-level data (>20 years) from 45 reference wetlands to characterize variation in multiple ecologically significant hydrologic indicators and quantify the length of record required for monitoring data to sufficiently capture long-term temporal changes. The effects of data temporal resolution of sampling frequency (i.e., quarterly, monthly, weekly, and daily) were also examined. Hydropattern was characterized using four primary types of indicators: magnitude, represented by annual mean, median, maxima, and minima; timing, characterized by annual dates of minimum and maximum; duration, quantified using the period the wetland was either below or above the 25th/75th percentile; frequency taken as the number of water level reversals and rate of change as reversals. Preliminary results demonstrated that for most metrics, the length of record required was variable. For magnitude, mean and median water levels had similar ranges (13 and 8 years minimum needed, respectively, and 38 years on average needed). Minimum water levels required longer length of records (38 years minimum needed and 39 years on average needed) while maximum water levels were obtainable with shorter length of records (4 years minimum needed with 19.5 years needed on average). Within each metric, the length of record needed was highly variable amongst wetlands, suggesting that wetland types contribute to hydropattern tendencies.

ABSTRACT. Wetlands are an important carbon storage reservoir, which makes them critically important for regulating global climate and biogeochemical cycles. While decades of research have investigated the drivers of wetland carbon storage and loss, fewer studies have quantified how plants—and specifically non-native plants—affect wetland soil carbon dynamics. To do so, we analyzed data from the Environmental Protection Agency's National Wetland Condition Assessment (NWCA), a nationwide survey that aims to quantify wetland condition and identify key stressors across the US, segmented into four main ecoregions. We used wetland vegetation and soil data from the US collected in 2011 (n=1023) and 2016 (n=1029); of these wetlands, n=121 were sampled in both years. Using this data, we asked the following questions: 1) what are the primary drivers of wetland soil organic carbon storage across the US? 2) is plant composition and specific functional traits associated with soil carbon storage? and 3) how did soil organic carbon and plant communities change between 2011 and 2016—and were these changes consistently correlated? Preliminary results suggest wide variation in wetland carbon storage explained primarily by wetland type and small, but significant, increases in wetland carbon storage in resampled wetlands between 2011 and 2016. Overall, we aim for this work to leverage a unique, large scale survey dataset to better inform the linkages between carbon storage and vegetation in wetlands across a wide geographic and disturbance gradient, providing guidance on how to better manage these important ecosystems.

ABSTRACT. Agricultural nutrient losses are a major contributor to the eutrophication of many waterbodies across the world. In the Lake Erie watershed, phosphorus (P) from drained agroecosystems is the primary driver of recurrent harmful algal blooms. Based upon a known correlation between soil and drainage P concentrations, it was hypothesized that legacy-P fields would be responsible for greater nutrient loads compared to fields with agronomically recommended soil P concentrations (“agronomic-P fields”). A public-private partnership consisting of researchers, agricultural retailers, and farmers was assembled to target best management practices to legacy-P fields (e.g., where greater nutrient loads were expected) in the western Lake Erie basin. Nine legacy-P fields were recruited and monitored yielding nutrient concentration and load data for the 2021 calendar year. This data was compared to loading data from a USDA edge-of-field monitoring network in the same region. At a monthly resolution, statistically significant differences were observed in drainage dissolved reactive P (DRP) concentrations (March) and loading rates (March and June). Average DRP concentrations for June were 0.22 mg/L and 0.06 mg/L for legacy-P and agronomic-P fields, respectively. The average loading rates were 14 g/ha compared to 4.5 g/ha during March and 38 g/ha compared to 4.3 g/ha during June for legacy-P and agronomic-P fields, respectively. However, cumulative subsurface DRP losses over ecologically important periods (March-July, annual) were not significantly different between legacy-P and agronomic-P fields. There likewise were no significant differences in TP concentrations or loads between the two types of fields except for greater TP concentrations from agronomic-P fields in December. Further comparisons will consider surface runoff contributions, while further differences may be observed from continued monitoring of these fields. Additional analyses will elucidate the factors that discern those legacy-P fields with greater nutrient losses to maximize the benefits of targeted management.

ABSTRACT. Impermeable urban surfaces such as roads, carparks and roofs contribute pollutants via untreated runoff to urban waterways, causing a wide range of adverse effects on the aquatic ecosystem. Total suspended sediment, copper and zinc, in particular, have been identified as key pollutants of concern in urban runoff. If urban waterways are to be sufficiently protected from runoff pollutants throughout effective stormwater management, then an easy-to-implement means of identifying specific pollutant sources is needed to enable targeted stormwater management planning and decision-making.

An event-based pollutant model, Modelled Estimates of Discharges for Urban Stormwater Assessments (MEDUSA), was developed to address these needs. It uses rainfall characteristics (antecedent dry days, intensity, duration, rainfall pH) and surface characteristics (material type, usage, condition, age) to predict sediment and heavy metal loads generated from individual impermeable urban surfaces.

The model was calibrated and validated on subcatchments up to 250 ha (620 acres). A key application has been to an industrial catchment that contributes stormwater to a sensitive coastal lagoon ecosystem in Timaru, New Zealand, enabling spatial mapping of areas of highest load generation. Providing load predictions at the individual surface scale allows engagement with individual property owners to improve their onsite stormwater management prior to discharge into the municipal system. Furthermore, MEDUSA can also be used to explore the pollutant reduction benefit of various management scenarios, including the effect of new policies controlling roof material types, the effect of maintenance, and the effect of at-source compared to end-of-catchment treatment. The model is now being rolled out across the city of Christchurch, New Zealand (>260 km2 (100 square miles)). City wide applications benefit a wide range of stakeholders, and ultimately contribute to healthier urban waterway ecosystems. Although the current focus has been on TSS, Zn, and Cu loadings, the model will be extended to incorporate nutrients.

ABSTRACT. Alabama State Route 180 located in Gulf Shores is a vital coastal roadway impacted by severe storms, high groundwater tables and future sea level rise (SLR). The area surrounding AL-180 supports a wide variety of ecological habitats for natural and nature-based features (NNBF). This project focuses on the effects of SLR on surface transportation infrastructure and the ability of NNBF to mitigate those effects. NNBF, such as living shorelines, combine ecological with conventional designs and can be expected to change substantially over their lifespan through natural processes. NNBF are also responsive to hydrologic conditions such as inundation, groundwater fluctuations, and wave action. To inform modeling of NNBF scenarios, we applied the Wetland Accretion Rate Model of Ecosystem Resilience (WARMER) to vegetated areas of proposed NNBF designs. WARMER predicts changes in marsh surface elevation relative to mean sea level using a 1-D model to capture the critical marsh accretion processes. We parameterized WARMER using marsh sediment core data collected by previous studies in Bon Secour Bay paired with NOAA predictions for SLR in the northern Gulf Coast region. Based on Juncus roemerianus decomposition rate of -0.254/yr, total volume per unit area of matter accumulated in the 1st, 2nd, and 3rd+ years is 1.026cm/yr, 1.059cm/yr, and 1.112cm/yr respectfully. Under the low and intermediate-low SLR scenarios, the accretion processes will continue to outpace SLR over the next 150 years. Marsh surface elevation begins to decrease under intermediate or intermediate-high scenarios, predicting complete inundation after 141 years using the high scenario. Future work on this project will apply new simulations of coastal hydrologic dynamics under a changing climate as model inputs, allowing us to understand how the function of NNBF will evolve as part of a dynamic system.

ABSTRACT. With more and more waterbodies being degraded and deemed as “impaired” for water quality conditions, exacerbated by flooding, water supply shortages, and sea level rise and saltwater intrusion impacting groundwater wells and communities, engineers and scientists, alongside Federal and State agencies, are pressing hard to resolve these complex issues. There have been valiant efforts to protect, restore, manage and sustain ecosystems across the nation. However, these efforts have been carried out at relatively small scales, taking many years to decades to implement using the conventional design-bid-build project delivery method.

A new project delivery method, the turnkey project approach, delivers ecological uplift and adaptive improvement projects that are rooted in science-based design, and long-term stewardship. By invoking the turnkey approach, entities can more efficiently build and sustain sites that preserve environmental balance, lifting impaired ecosystems into restored health and ultimately, self-sufficiency and preparing ecosystems and communities for the next challenges our changing climate will bring.

The method begins at the data-driven land siting and acquisition stage, then dovetails into the design, permitting, construction, monitoring, and maintenance to guarantee project performance. This approach allows for a reduction in costs and time needed to implement and has helped government entities expedite meeting their mitigation, permit requirements, MFLs and TMDLs. A case study for siting criteria for restoration projects will be presented to exhibit first steps in the process for developing turnkey projects, identifying a set of conditions where turnkey delivery makes sense.

ABSTRACT. Urbanization and population growth are building resource strain and urban development is impacting environmental resiliency. Urban and peri-urban agricultural production is being threatened by competition over land use, increasing profitability of solar farming, and rising demand for renewable energy farming in urban areas. Combining agricultural production and rainwater harvesting with solar energy production can protect ecosystems and ensure sustainable synergy. The implementation of such innovative agricultural systems can help build community and environmental resiliencies. University of D.C. researchers have developed a triple yield (food, water and energy) system that incorporates solar panels and cisterns into an agricultural system to capture energy and water while producing high-value specialty crops in protected microclimates. We hypothesize that such a system is feasible in urban areas by using solar energy to pump water for drip irrigation and cisterns to collect rainwater from the panel surfaces. This system includes four treatment groups with six replicate plots: 30° solar panels, 45° solar panels, 60° solar panels, and no solar panels. A range of crops have been grown in the system, predominantly leafy greens, including arugula, collard greens, kale, mustard greens, spinach, and swiss chard. Current field scale experiments determine overall productivity with respect to the different treatments. Ongoing data collections include plant size and health, solar energy collection in kWh/m2, and rainwater collection quantity. Preliminary results indicate that the crops grow best beneath the panels, particularly the 30° and 45° solar panels, and that the 30° solar panels capture the most solar energy and rainwater; more specific findings to be shared at the conference. Thus, our research incorporates natural elements such as sustainable agriculture, water reuse and canopy shading into the popular practice of solar farming to decrease land competition while meeting increasing resource demand.

ABSTRACT. Each year in the U.S., 60,000 acres of natural wetlands are lost to development. To compensate for this, these wetlands must be “replaced” elsewhere by constructed wetlands to comply with “No Net Loss” policies, which aim to mitigate wetland surface area loss. While wetlands have the potential to significantly reduce atmospheric CO2, there is a lack of literature tracking how much carbon constructed wetlands sequester as they age. This knowledge gap precludes policy makers from knowing the long-term benefits that constructed wetlands provide. The Olentangy River Wetland Research Park is a research facility that is uniquely qualified to address this knowledge gap. Two constructed riverine wetlands in this park have some of the longest running datasets for constructed wetlands. I have identified 32 sites within these wetlands that were sampled in 1993, 1995, 2004, 2013, and 2022. My study will be the first to quantify carbon sequestration in constructed wetland soils over a 29-year, continuous timescale. These results will clarify mature constructed wetlands’ role in carbon sequestration, which will inform design, management, and legislation of wetland conservation and construction. Furthermore, these results can speak to whether “No Net Loss” policies are promoting wetland development that ensure long-term quality of these carbon sinks.

ABSTRACT. With a decreasing intensity and frequency of freeze events, coastal wetlands globally are undergoing ecosystem transitions as the poleward expansion of mangroves encroaches into salt marsh, especially in tropical-temperate transitional zones. Such transition triggers changes in coastal wetland ecosystem services, including coastal protection, nutrient removal and wildlife habitat. Here, we characterized how mangroves respond to temperature minima across levels of community, population and individual at 18 sites along Florida’s Gulf of Mexico coast (USA), to provide implication for coastal ecological engineering projects such as living shoreline and coastal accretion to adapt sea level rise. Warming scenarios could trigger linear accumulation of mangrove biomass, and canopy height and coverage of mangroves in north could experience dramatic increase to resemble the landscape in south mangroves. Species-specifically, A parabolic and positive linear relationship with temperature minima were found for abundance and coverage of tall A. germinans and tall R. mangle population respectively, suggesting R. mangle might take over dominancy from the pioneering A. germinans with warming scenarios. The projections suggested a faster rate of elevation accretion, enhanced coastal protection, alteration of habitats for fishery and increasing need for site-specific mangrove management while implementing traditionally marsh-based living shoreline in Northwest Florida.

ABSTRACT. The Teaneck Creek project site is a low-lying site surrounded by residential and commercial development. Prior to the site’s recent acquisition as a County Park, the site was used as a rubble fill and as a place for the surrounding urban development to discharge uncontrolled stormwater. Based on interest from The Teaneck Creek Conservancy and The Bergen County Audubon Society, Bergen County and Rutgers University decided to contract Biohabitats to design this project, which involved excavating the rubble mounds and 1-ft of the surface soils dominated by Phragmites. We used a stormwater best management practice called regenerative stormwater conveyance to repair the eroded stormwater flowpaths and attenuate the delivery of stormwater. Using readily available sand and woodchips supplied by Bergen County to create a hyporheic treatment layer, we designed an approximately 20-ac sand seepage wetland that used the stormwater supply from the surrounding urban and commercial landscape as the basis for wetland hydrology, storing runoff in more than 20 shallow wetland pools. The water in these pools slowly drains through the carbon-rich sand (hyporheic) layer vegetated by native species on its ultimate path to Teaneck Creek. The RSCs, pools, and seepage berms treat the stormwater runoff, reducing runoff quantity and reducing peak discharge, while improving quality through physical, chemical and biological treatment processes, delivering cleaner, cooler water to Teaneck Creek. Construction was completed in the Fall of 2022 and we have seen tremendous increases in habitat, wildlife, and community interest. We will walk through the project design, construction and future management efforts as a model for innovative, urban habitat restoration.

ABSTRACT. A section of the Roanoke River in southwestern Virginia is listed as an impaired water due to high fine sediment loads being a biological stressor. Tributaries draining into the Roanoke River, including Lick Run, were assigned a target sediment reduction goal as part of the Roanoke River total maximum daily load (TMDL) Implementation Plan. The Lick Run watershed was assigned a 75% sediment load reduction target, and as an MS4 permit holder, the City of Roanoke is responsible for meeting the reduction target. A watershed modeling effort using the U.S. Environmental Protection Agency’s (EPA’s) Storm Water Management Model (SWMM) was used as a planning tool to identify locations for installation of new stormwater best management practices (BMPs). To assist with long term planning, a potential 130-ac. development was included in the assessment. New stormwater infrastructure costs were considered with respect to infrastructures’ life cycle and environmental impact. An additional point of study for the Lick Run area is that many developers meet water quantity reduction standards, but outsource water quality reduction standards to trading programs. While trading proves cost-effective in the short-term, the practice results in local stream degradation which could be mitigated if water was treated on-site. The goal of this watershed modeling and planning assessment is to identify the stormwater infrastructure investments needed to meet TMDL requirements and assess the effect of trading on sediment loads within Lick Run.

ABSTRACT. Stormwater runoff is a primary carrier of pollutants to the nearby streams and lakes in the Puget Sound region. Green Stormwater Infrastructure (GSI) is built to intercept stormwater runoff to mitigate peak flows and stormwater pollutants before they reach surface waters. A rain garden is a type of GSI comprising a plant-soil system where water retention and pollutant mitigation is maximized through infiltration and storage. Proper placement of rain gardens within the watershed is crucial to maximizing their cost-effectiveness. The Lower Puyallup River Watershed, situated in South Puget Sound, consists of primarily residential areas of the cities of Puyallup and Tacoma. Preventing water quality impairment is essential as the streams and rivers in the watershed are critical habitat for Chinook and Coho salmon that return for spawning. The study's objective was to develop a framework to identify suitable sites for rain gardens in an urbanizing watershed. An indexing approach to identify Hydrological Sensitive Areas (HSA) was adopted, in which we considered the topography, runoff contributing area, soil depth, and hydraulic conductivity. The Topographic Wetness Index (TWI) and Soil Water Storage Capacity (SWSC) were computed to obtain the Hydrologic Sensitivity Index (HSI). Areas considered infeasible per criteria specified by state and county regulations were removed, and the HSI was classified based on suitability for the construction of rain gardens. The moderate HSI range (8.2–11.8) was deemed most suitable for rain garden placement in the study area. More than 500 suitable sites were identified providing a practical, scalable, and transferrable tool for prioritizing the placement of rain garden for stormwater runoff management.

ABSTRACT. While green stormwater infrastructure (GSI) has been mainly an approach aimed at improving water quality, its potential for flood management has gained more attention recently. The potential for reducing the impact of urbanization on existing undersized stormwater networks using GSI is investigated in this study using the City of Dallas as a case study. Flood prone areas were identified for the current 2-, 10- and 100-years storm as well as projected 2045 2-, 10- and 100-years storms based on the RCP 8.5 scenario using CMIP 5 model and the EPA SWWM 5.0 model. Once flood prone areas were identified, appropriate GSI practices (rainwater harvesting, rain gardens and bioretention) were modeled in each of the flood-prone subwatersheds. The volume reduction from each of the design storms was estimated and the benefit of GSI per gallon reduced was compared to the cost of grey infrastructure upgrades needed to accommodate the extra runoff volume. The results show that while neither option was able to eliminate the overflow in three of the seven priority watersheds, green infrastructure reduces overflow at a much lower cost. Green infrastructure is a promising cost-effective solution for stormwater management problems in the city of Dallas, and GSI should be considered first for capital investment while grey infrastructure should complement GSI to meet flow reduction targets when GSI alone is not enough.

ABSTRACT. Over the past 30 years, monarch butterfly (Danaus plexippus) populations have declined by over 90%. This is primarily because milkweed plants (genus Asclepias), their only reproductive habitat, have been replaced by agricultural and urban land. Restoration of this habitat is critical for the recovery of monarch populations. This study investigates the potential of bioretention cells engineered for stormwater management to be used as multifunctional ecosystems that also help restore monarch reproductive habitat. Fourteen bioretention cells in Columbus, Ohio were selected for this study, along with three natural milkweed patches (the control). Pots of common milkweed (Asclepias syriaca) and butterfly milkweed (A. tuberosa) were placed in the experimental sites in eight different combinations to test whether 1) the species of milkweed or 2) having that species potted or planted had an effect. The plants were checked weekly for monarch eggs from June to September from 2020-2022. Each visit, the number of eggs at each site was counted and the species of milkweed the eggs were laid on was noted. The number of eggs was normalized according to the number of plants at each site. No significant difference was found between the number of eggs laid in rain gardens and the number laid in natural milkweed patches. Additionally, results suggest that the diversity of milkweed species in the rain gardens positively impacts how many eggs were laid at each site. This research shows that planting milkweed in bioretention cells is a great way to integrate monarch habitat into our own human infrastructure and help restore some of the habitat that's been lost to urbanization and agricultural expansion. These results will be used by the City of Columbus, and could be used by other cities with similar green infrastructure initiatives, to manage bioretention cells to support monarch butterfly populations and other pollinator species, in addition to managing stormwater. If cities continue adopting evidence-based management strategies for monarch rehabilitation using bioretention cells, this could boost the recovery of monarch butterfly populations.

ABSTRACT. Food production and associated supply networks in the US have a significant negative impact on the environment, contributing to 33.6% of freshwater withdrawal and 8% of greenhouse gas emissions. In contrast, potentially hydroponics and aquaponics are more sustainable alternatives as they recycle water, use less area, and emit less carbon dioxide than traditional farming methods. The potential environmental, economic, and social impacts of implementing hydroponic and aquaponic systems in the Washington, D.C. region are being evaluated through a life cycle sustainability assessment (LCSA) at the Urban Food Hubs run by UDC. We have been experimenting with black magic kale, lettuce, basil, and some microgreens such as radish. SIMAPRO software is being utilized to quantify the environmental performance of the three different agriculture systems. LCA will be utilized to estimate total life cycle costs (e.g., Acidification, & Eutrophication potential-EP & global warming potential-GWP, etc.). Preliminary results from the SIMAPRO software show that 0.00035 Kg CFC-11 eq of ozone depletion and 2.993E3 Kg-CO2 eq global warming from greenhouse materials used in hydroponics is caused by the glass panel used as roofing during the construction phase. While the use of nutrients in the hydroponics caused 4.36E-8 Kg CFC-11 eq ozone depletion and 0.648 Kg-CO2 eq global warming. This study is contrasting soilless food production techniques with conventional soil-based agriculture and is identifying gaps in data that must be filled to undertake LCA, LCC, and sLCA. This project is pioneering to assess the advantages of hydroponics and aquaponics in urban settings from a sustainable perspective, and the LCSA framework being developed will provide municipal authorities with the tools they need to make informed policy decisions and improve manufacturing methods. Overall, this study will help to establish the benefits and drawbacks of hydroponics and aquaponics in urban agriculture, with a focus on sustainability.

ABSTRACT. Natural and constructed wetlands are now frequently used across the United States for mitigating nitrate losses to both surface and groundwater. Though the use of wetlands as a treatment approach for nitrate in runoff is well known, other active contaminants regularly co-occur with nitrate, potentially affecting the efficacy of nitrate-N removal. For example, veterinary pharmaceuticals have been observed in runoff originating from fields that receive livestock facility animal waste. In 2022, two mesocosm experiments were conducted to evaluate the combined effects of 4 common-use veterinary antibiotics (VAs) (chlortetracycline, sulfamethazine, lincomycin, monensin) on nitrate-N reduction efficiency. We hypothesized veterinary antibiotics would significantly impact nitrate-N removal through changes in denitrification processes within wetland ecosystems. To test this hypothesis, we simulated two pulse-flow storm events (2.5mg N03-N/L, 7.5 mg N03-N/L) and quantified the combined effects of trace-level antibiotics (1.0 mg/L) on the nitrogen cycle in fully saturated treatment wetlands. Results from previous experiments we conducted suggest nitrate reduction rates in treatments receiving antibiotics (CA= -1.04, FTWA= -1.31) remove nitrate more efficiently than those without (C= -0.01, FTW= -0.52). Plant uptake of VAs was also assessed, with results indicating that accumulation of VA compounds in wetland plants occurs and is primarily limited to the below ground biomass (above ground=1.6 mg m-2 total assessed veterinary antibiotics, below ground=574.1 mg m-2 total assessed veterinary antibiotics). Findings from these experiments will provide new insight into whether antibiotic residues in wetland environments affect proposed mitigation strategies for controlling nitrogen losses from fertilized crops and managing nitrate contamination of ground and surface water.

ABSTRACT. Wetland morphology is a key variable controlling wetland ecosystem functions that are key to success of restoration projects, including ecosystem gross primary productivity (GPP), greenhouse gas production, and denitrification. Generally, as wetlands become larger, terrestrial influence on ecosystem structure and function decreases. This includes reduced inputs of organic matter from terrestrial plants and increasing light exposure as canopy recedes. As wetlands become larger, water column concentrations of dissolved organic carbon (DOC) will generally decrease due to photodegradation and reduced terrestrial inputs. Further, these changes also alter the composition of DOC, decreasing aromatic content and optical density. These changes to light availability correlate to increased rates of GPP. Increased GPP drives higher variability in water column oxygen levels, potentially inhibiting redox-sensitive processes such as denitrification. Though methanogenesis is also a process that is typically favored by highly reducing conditions, there is emerging evidence that water column methane levels in lakes and wetlands can increase when aquatic GPP is high. Thus, understanding how wetland morphology influences ecosystem processes can help wetland managers and restoration practitioners identify strategies for increasing denitrification and decreasing greenhouse gas production. To test our hypothesis that GPP and methane levels would be positively correlated to water body size and that denitrification rates would decrease with increasing wetland size, we studied wetlands and lakes across Indiana. We measured DOC quantity and composition, nutrient content, methane concentrations, and denitrification rates across these systems. We estimated GPP using dissolved oxygen time series obtained from MiniDot dissolved oxygen sensors. We found that GPP increased and denitrification decreased with wetland size. Further, GPP was positively correlated to water column methane concentrations. Our results suggest that wetland morphology is a critical top-down influence on wetland ecosystem function that may help practitioners identify wetland restoration sites with the highest probability of success.

ABSTRACT. This was the first study to combine cavitation, anaerobic digestion (AD), and microbial electrolysis cell (MEC) and show high energy production from complex waste sources, such as black water and food waste (BW-FW), in a short time-period (10-days) through biological processes. The study investigated the effects of: 1) hydrodynamic cavitation to make organic material from BW-FW solids more available for energy production, 2) increases in methane (CH4) production from AD with MEC incorporation (AD-MEC), and 3) electric-coagulation (EC) to decrease organics and remove color from the liquid portion of the waste after settling. Digestion after cavitation generated 62% of the cumulative CH4 within 5 days and 81.2% after 10 days of the 30-day batch digestion, increasing the digestion rate by 12% compared to AD-only. Operating the AD-MEC at 1.2V resulted in more CH4 production than the MEC at 0.5 V and 0.9 V by 15.6% and 2.6%, respectively, with 26% higher CH4 production at thermophilic conditions (55°C) compared to mesophilic conditions (35°C). The novel EC technique to treat that the liquids after the 30 min gravity settling was tested using four EC voltages (10, 15, 20, and 25 V) for 5-90 min. The mass balance showed that after solid separation 90% of the BW-FW mixture proceeded to the liquid portion and had 93% reduction in COD (from 2,980 to 200 mg/L COD) and 100% reduction in total suspended solids (TSS) using EC treatment. The combination of these processes: settling, subcritical water cavitation pre-treatment, electrocoagulation, anaerobic digestion, and microbial electrolysis cells, was shown to greatly increase CH4 production volumes and AD production rate, EC integration showed how the combined system can meet water quality goals for low tier water for reuse, while surpassing energy production of non-enhanced AD systems.

ABSTRACT. This project is extensively investigating the roles of five specific scavenging materials (zeolite, activated carbon, silica gel, turface, aerogel, and chitosan) to adsorb certain volatile organic compounds (VOCs) and promote nitrification together with water contaminants adsorption in batch and pilot scale aquaponic systems. These scavenging materials have been shown to have relatively high adsorption capacities for water contaminants and are expected to be able to significantly reduce the concentration of contaminants like ammonium (NH4+) in the aquaponic systems while providing a surface for nitrifying bacteria to grow due to their high surface area and porosity. Preliminary batch experiments showed low ammonium adsorption by the scavenging materials, with adsorption capacities of 0.0608 (mg NH4)/(g Silica Gel) for silica gel, 0.06304 (mgNH4)/(g Zeolite) for zeolite,0.0408 (mgNH4)/(g Turface) for turface, and chitosan having no effect on ammonium levels. The scavenging materials could be adsorbing less than expected due to having the wrong functional groups to adsorb the ammonium, which could be changed by chemically treating the materials. Different material characterization tests such as BET surface area analysis, Fourier-transform infrared spectroscopy (FTIR) analysis and Boehm titration are being incorporated before further pre-treatment (e.g. conditioning zeolite to a cationic form using chloride salts) to improve adsorption capacity, the pretreated materials will be tested in batch again to determine their improved ammonium adsorption capacities and will also be tested with other contaminants such as nickel, silver, and VOCs such as CO2, Benzene, and Methane. Finally, the systems have been designed and scavengers will be implemented into pilot-scale aquaponic systems where water contaminants will be constantly monitored as well as the essential water and air quality parameters will be determined alongside documenting fish and plant growth parameters.

ABSTRACT. The algal turf scrubber (ATS) is a bioremediation technology that uses periphyton “turfs” to metabolize nutrient pollution from eutrophic water. These systems continuously generate algae biomass as a byproduct, which contains sequestered nutrients. Anaerobic digestion has been demonstrated to be effective to break down the algal waste from ATS in the Chesapeake Bay Watershed, allowing for nutrient recovery and the generation of bioenergy in the form of methane (CH4) as a value-added product. However, the high moisture content (>90%) of algae from ATS results in a low volume of CH4 generated per mass of algae digested. This experiment applied five settling and coagulation treatments (gravity, FeCl3, electrocoagulation, chitosan, and Bacillus sp. RP 1137) at 2-3 different dosages to 500-mL samples ATS algae to settle cells out from suspension. The clarified supernatant was then removed to dewater the settled solids, which were digested for 35 days in a laboratory-scale biomethane potential test to measure CH4 yield.

The raw ATS algae had a total solid (TS) of 4.02 ± 0.08%, total suspended solids (TSS) of 35.7 ± 0.8 g/L, and volatile solids (VS) of 17.0 ± 1.0% of the TS. The five dewatering treatments increased the TS of the algae by 14-291% depending on the treatment, with electrocoagulation the least effective and bacterial coagulation the most effective. All treatments, including gravity, reduced total suspended solids (TSS) in the supernatant by >98%. In the digestion experiment, the raw algae yielded 49.6 ± 3.6 mL CH4/g VS, or 1.65 ± 0.12 mL CH4/g algae digested. The dewatered solids had reduced digestion efficiency per mass VS by 29.6-71.0% compared to the untreated algae. However, solids dewatered with electrocoagulation, FeCl3, chitosan, and bacteria had 20.7-983% higher CH4 generation per mass of algae digested.

ABSTRACT. Algal Turf Scrubber systems, which utilize filamentous algae for wastewater treatment, are a promising alternative or complement to traditional wastewater treatment processes. These systems are simple in design and function, with water flowing through an inclined flow lane where the algal community grows and removes nutrients from the wastewater. Despite their efficiency in large-scale applications, there is limited organized knowledge regarding the growth, competition, and dynamics of the species that comprise the periphytic community in these systems. To fully attain the potential of Algal Turf Scrubber systems for wastewater and water treatment, as well as for research purposes, it is crucial to develop a descriptive model that can be used for design and prediction. The model should account for the complex and dynamic interactions between hydraulic and biological factors, both within and outside the algal community, and the physical attachment of the algae to the surface in the flow lane. This project aims to start to address these challenges by developing a model that incorporates light-based effects in different strata of an Algal Turf Scrubber community, as well as a nutrient-based interaction model between two dominant genera of filamentous algae in this type of system, Cladophora sp. and Stigeoclonium sp. The model considers the competitive interaction between species, favoring the growth based on the available environmental conditions and with parameters established based on literature and laboratory experiments. In its simplicity, this model can incorporate more and other species, being limited to the need for more basic physiological data on filamentous algae. This model provides a first step towards a descriptive model of algal growth in an ATS system, to enable the use of ATS systems in wastewater and water treatment and as a research tool.

ABSTRACT. The AEES Body of Knowledge (BOK) committee is charged with defining and updating the core set of knowledge, skills and abilities that underpin the practice of ecological engineering in support of AEES’ vision to lead ecological engineering education and provide guidance for academic programs. Accreditation is one of the tools available to provide guidance to ecological engineering academic programs. Following general consensus of the AEES membership, the BOK committee has been working to accredit ecological engineering academic programs with primary goals of (1) raising the profile of our discipline, (2) making ecological engineering education more visible and accessible to future students and (3) enabling AEES to take a lead in defining the educational criteria needed to prepare students for productive careers in the field. In the US, engineering and technology programs are accredited through an organization known as ABET (Accreditation Board for Engineering and Technology). This presentation will provide an update on the BOK’s work with ABET and affiliated professional societies to create accreditation criteria for ecological engineering programs, with a majority of focus on work that has occurred in the past year. Among the recent developments to be discussed include (1) partnership with ASABE, AAEES (Academy of Environmental Engineers and Scientists), and, more recently, ASCE as co-leads on the ecological engineering criteria, (2) efforts to identify potential programs that may accredit ecological engineering programs once the criteria are created, and (3) adjusted timeline for the ABET process, with time for discussion to follow.

ABSTRACT. Exposure to STEM working professionals and access to appropriate resources substantially impacts students’ motivations and decisions to pursue STEM degrees. Access to these types of social capital can be particularly challenging to students underrepresented in STEM disciplines, including women, people of color, and those whose parents did not attend college. Without proper introduction and exposure to the diverse field of engineering, many children have misconceptions and stereotypes about what engineers do. This lack of exposure and information could lead to a lack of interest in pursuing engineering as a career pathway. This study explored how underserved and minority 3rd through 8th grade children’s definition of, motivation to pursue, and sense of belonging in engineering change after a) learning about and interacting with local ecological engineering infrastructure and b) engaging with underrepresented engineering mentors (university faculty and students). Study activities took place at an after-school program and included teaching students about different types of engineering occupations (with an emphasis on ecological engineering), hands-on water testing of a local floating treatment wetland installation, and interacting with and learning more about the pathways of underrepresented university student and faculty engineers. Before these activities, the research team distributed surveys to understand children’s existing knowledge and attitudes of engineering and engineering careers. The team again distributed these measures after study activities to understand how the activities potentially changed children’s definition of and motivation to pursue engineering. Preliminary results indicate the percentage of students considering engineering occupations rose from 21% to 51% from before and after participation, and that the percentage of students considering going to college rose from 55% to 64%. Through hands-on ecological engineering activities and interactions with underrepresented engineers, participants appear to have become more motivated to pursue engineering pathways.

ABSTRACT. We are facing increasingly complex environmental issues with climate change and land use conversion than ever before, and these are embedded within social, political, and regulatory contexts that can be difficult to navigate. The integration of research, design, and implementation to create resilient solutions for communities and landscapes is paramount. Many recent frameworks and guidelines have emerged that include core principles, rules, and standards for ecological restoration, ecosystem-based design, and nature-based solutions. While these are helpful, some were too broad and lacked specificity while others were too narrowly focused on individual biomes or ecosystem types. They were also missing connections between research, extension, and implementation. Based on a review of the literature and unstructured conversations with researchers, extension professionals, and practitioners, we developed a set of 9 core principles that underpin effective, equitable, and resilient stream restoration programs. In this talk, we welcome your feedback with the hope that this effort will amplify and energize the dialogue about how to move the science and practice of stream restoration forward.

ABSTRACT. In urban riverscapes, nature-based solutions (NbS) and natural infrastructure (NI) can provide a spectrum of environmental, societal, and economic benefits, but widespread implementation of NbS and NI remains limited due to their context-dependent nature. Recently, windows of opportunity have opened through legislation and funding to expand NI solutions that address flooding, water quality, air pollution, extreme heat, and environmental equity. System-level approaches may offer these projects a framework that is flexible yet holistic enough to streamline implementation, and a systems approach is essential to realize the potential of NbS and NI for equitably achieving these goals. The purpose of this project was to support managers and decision-makers in prioritizing their conservation and capital investments in urban riverscapes for flood risk reduction, water quality improvement, and ecosystem restoration in addition to identifying and leveraging social co-benefits. A spatial multi-criteria decision analysis (MCDA) is well suited to landscape-scale environmental risk management and scenario comparisons, as it provides a logical and transparent way to incorporate multiple, competing goals and priorities from a variety of stakeholder groups. We conducted an urban stream spatial MCDA case study with Charlotte-Mecklenburg Storm Water Services to guide equitable and efficient stream reach, floodplain, and watershed interventions. Our study assessed social and ecological characteristics of the system and prioritized watersheds and sub-basins for potential NI using a spatial MCDA. We will present an urban stream prioritization framework that could be tailored to complement existing management strategies and also more broadly implemented in other social-ecological systems.

ABSTRACT. In 2020, Black and Hispanic students earned only 4.4 percent of doctorates in engineering (ASEE, 2021). Similarly in academia, historically underrepresented minorities represented just 6.4 percent of tenured and tenure-track faculty in engineering (ASEE, 2021). Previous research has shown the correlation between altruistic values and increased motivation in STEM for historically underrepresented and low-income students (Thoman, et al., 2015; Brown, et al., 2015; Smith, et al., 2014). Given their inherent focus on creating solutions and designing ecosystems that improve human health and provide research convergence with other disciplines (anthropology, biological sciences, chemistry, environmental science, data science, geoscience, hydrology, mathematics, microbiology, and public health) to address social justice, ecological or environmental engineering programs can be powerful change agents in fostering STEM diversity (May, 2022; Blaney, et al., 2017). This presentation will discuss inclusive practices (e.g., intentional recruitment of historically underrepresented undergraduate researchers, holistic graduate admissions, culturally inclusive mentoring, reciprocal partnerships with minority-serving institutions, BS-MS-PhD bridge programs, community-building and professional development activities) that have been the framework of the Alfred P. Sloan Foundation Minority PhD/University Center of Exemplary Mentoring (2005-present) and other signature initiatives at the University of South Florida (USF). These efforts are reducing structural barriers (e.g., over-emphasis on grade point average and test scores, limited research opportunities, and lack of access to mentors), and increasing belongingness in STEM doctoral graduate programs, while reimagining career pathways in engineering for historically underrepresented students (Diaz-Elsayed et al., 2023; Espinosa et al., 2022; Batchelor et al., 2021; NSTC, 2021; NAS, 2019; Espinosa et al., 2018; Rudolph et al., 2019).

ABSTRACT. The Biden Administration has made a real effort to incorporate Indigenous, Traditional Ecological Knowledge (ITEK) into all aspects of federal decision and policy making. Conceptually, this goal is admirable. As is often the case, taking this high-minded aspiration and implementing it in a practical, meaningful way presents many difficulties in a legal and regulatory framework that emphasizes engineered solutions and economic cost/benefit analysis rather than finding harmony with natural systems and less quantifiable, but equally important sources of value that comprise ITEK for many Native American tribes, such as the Seminole Tribe of Florida. Stephen A. Walker, will share experiences and his perspective on this issue from his decades spent representing the Seminole Tribe of Florida as outside counsel on a number of critical matters related to Everglades restoration. He will discuss issues that have arisen as federal agencies have engaged tribal staff to plan and implement complex environmental restoration projects including: how to site large infrastructure consistent with Tribal values, how to incorporate ITEK into the operation of key infrastructure, and how to be heard during planning processes that are dominated by non-native stakeholders and their perspectives/concerns.

ABSTRACT. With funding from the National Science Foundation the “Large-scale CoPe: Reducing Climate Risks with Equitable Nature-based Solutions: Engaging Communities on Reef-Lined Coasts” Hub explores risks and benefits to communities in tropical coastal areas where replenishing coral reef and mangrove ecosystems have been piloted and can be scaled up to national and/or regional management levels as “Nature-based Solutions” (NBS) to better protect communities. The work focuses on key sites across three regions with diverse coastal, coral reef-dependent communities in Florida, the US Virgin Islands, and in Belize. The goals are 1) to establish an inclusive participatory co-design approach for assessing current and future coastal risks and rigorously quantifying the benefits of NBS, including coral reef and mangrove restoration and protection, for equitably reducing risks while enhancing human well-being, economic recovery, and biodiversity benefits, and 2) to assess how community experiences of risk differ and affect NBS implementation and adaptive capacity to mitigate increasing climate change related impacts.

Our vision is to empower coastal communities by collaborating and co-creating new knowledge of how ecosystem-based processes can help address climate risk to inform equitable place-based and appropriate NBS. The expanded and standardized use of NBS also opens the opportunity to broaden participation of diverse stakeholders in the climate adaptation process throughout the lifecycle of the research. This talk shares experiences during year 1 of this 5-year project on fostering team science, convergence research, and community engaged research. It also provides a summary of approaches emerging from the project team for selecting sites for research and for considering equity as it relates to NBS across 3 geographies.