Browsing by Subject "Water Quality"

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62nd Minnesota Nutrition Conference
(University of Minnesota, Extension Service, 2001-09) University of Minnesota, Extension Service
Agricultural Wetland Restoration: The Role of Sediment Removal, Hydroperiod and Time on Restoration Outcomes
(2021-06) Winikoff, Sarah
Restoring agricultural wetlands to remediate nutrient runoff, decrease flood risk, and improve wildlife habitat are areas of growing interest. One restoration strategy that may improve species diversity, enhance water retention, and decrease nutrient availability is the removal of accumulated eroded sediment from agricultural wetlands prior to restoration. In this work, we the measured physical and chemical characteristics of soils, characterized plant communities, and examined water column nutrient availability and denitrification potential in 54 restored agricultural wetlands in west central Minnesota. In half of the wetlands hydrologic function was restored by removing and plugging drainage tile and ditches, while hydrology was restored in the remaining basins following sediment removal (Excavation treatment), increasing basin depth by an average 30 cm. Excavation primarily influenced the plant community, by delaying the establishment of two invasive emergent macrophytes, hybrid cattail (Typha x glauca) and reed canary grass (Phalaris arundinacea), but the affect only lasted for 6 years. Contrary to expectations, soil properties, water column dissolved nutrients, and denitrification potential were all primarily influenced by hydroperiod – the number of consecutive days with standing water. Wetlands with longer hydroperiods had less bioavailable P in soils, lower dissolved N and P concentrations, and lower denitrification potential. We also found evidence that vegetation likely plays an important role in dissolved nutrient dynamics over time. Our results suggest that excavation may be an important tool in wetland restoration but its influence was lost as wetlands aged in the absence of invasive species management. Moreover, nitrogen and phosphorus dynamics were almost universally controlled by hydroperiod, with tradeoffs between nitrogen removal and phosphorus remineralization.
City of Prior Lake Sustainability Implementation Plan
(Minneapolis: Center for Urban and Regional Affairs, 2009) Finis, Abby; Schaum, Jessica; Torres, Angela; Shrestha, Grishma; Cannon, John
Clean Water: Everybody's Concern
(Minnesota Agricultural Experiment Station, 1988) University of Minnesota. Agricultural Experiment Station
DISSOLVED PHOSPHORUS DYNAMICS AND MANAGEMENT WITHIN THE AGRICULTURAL LANDSCAPE
(2022-05) Bender, Laura
Agricultural phosphorus loss was identified as a water quality priority within the Minnesota Nutrient Reduction strategy identifying a 45% yield reduction goal. Implementation plans call for total phosphorus (TP) reduction with traditional management strategies designed for erosion control and particulate nutrient removal, leaving the dissolved, or bioavailable, forms of phosphorus un-accounted for. Substantial yield increases in agricultural tributaries over recent decades highlight the need for dissolved reactive phosphorus (DRP) management, with some sources documenting over 50% DRP contributions to TP loads in Minnesota. DRP, hydrology, management and site-specific factors were investigated at two field research sites in southern Minnesota, with additional data harnessed from the Minnesota Discovery Farms Program. Data was used to assess the impacts of various site and management factors including cover crops, riparian buffers, edge-of-field wetlands, tillage category, fertilizer application and soil properties on phosphorus loads from farm fields and edge-of-field best management practice (BMPs) uptake. Four project objectives were addressed; 1.) to quantify and characterize current and target DRP yields from Southern Minnesota agricultural fields, 2.) to quantify the influence of local field and management conditions on DRP yields, 3.) to assess the effectiveness or inefficacy of common management practices for phosphorus and nitrogen removal, and 4.) to explore novel management strategies for DRP yield reductions including treatment trains, microbial soil amendment and plant harvest. Methodology included hydrologic monitoring, soil assessment, edge of field nutrient concentration analysis and measurement of phosphorus in vegetation to track phosphorus movement through the soil, water and plant components of agroecosystems. Current DRP loss rates from agricultural fields were quantified at 0.49 kg ha-1, with a target DRP yield of 0.27 kg ha-1 to achieve a 45% phosphorus reduction. To meet target yields, project results demonstrated the importance of both surface and subsurface DRP loss pathways, legacy phosphorus monitoring and management and the need for coordinated edge of-field and in-field management strategies. Significant conditions driving drain tile DRP concentrations included manure application rate, number of tillage passes and soil test phosphorus (STP). Significant conditions driving surface DRP concentrations included cumulative manure and fertilizer application rate and STP. STP accumulation was driven most significantly by manure application rate, number of tillage passes, organic matter content, clay content, soil pH and cover crop implementation. Cover crops, which were placed into the context of an agricultural treatment train, were found to reduce subsurface DRP concentrations by 63% and annual yields by .07 kg ha-1 through reduced constituent mobilization at higher flows but also to contribute to increased STP. Crop use efficiency, fertilizer application and soil phosphorus draw down where also associated as part of a mass balance to further correlate management action to DRP yields. Research findings will help to inform agricultural management for DRP removal strategies necessary for setting and meeting realistic nutrient reduction and water quality goals.
Dynamic Lake water quality simulation model "Minlake"
(1987-08) Riley, Michael J.; Stefan, Heinz G.
Lakes are in a continuous state of change. Some changes occur over very short periods of time on the order of hours and minutes. Other changes mark long-term trends in the biological and physical condition of a lake. Among the long-term trends in many lakes are a decrease in depth and an increasing productivity in a process called eutrophication. Typically, eutrophication occurs over a time scale of centuries. However, man-made changes to the watershed of a lake may result in a rapid acceleration of eutrophication such that significant changes in the water quality of the lake are noticed in a time span of a few years. Anthropogenic acceleration of eutrophication, known as cultural eutrophication, is due to agricultural, urban, and recreational development in the watershed of a lake which causes an increase in the nutrient loading to a lake. In response to the concern for the water quality of an eutrophic lake, many lake treatment practices have been developed. Treatment processes can be divided into watershed practice methods, inflow-outflow methods, and intake treatment methods. A partial list of these practices is provided in Table I. In some instances, treatment methods have been implemented without significantly improving the quality of a lake. The failure of a treatment method is often a result of a poor understanding of the short term dynamics of a lake which affect the rate and extent of cycling of nutrients within the water column, sediment, and biological components of a lake. To evaluate the effectiveness of lake treatment methods on Minnesota lakes, the Minnesota Lake Model (MINLAKE) has been proposed to model the principal dynamic relationships in a lake on a daily time scale. Treatment methods can then be modeled by modifying those components of the model which will be directly affected by the treatment process. The model can then predict the indirect and direct effects over a period of several months.
Environmental Sustainability Policies and Resources
(Minneapolis: Center for Urban and Regional Affairs, 2010) Shively, Emily
Essays on the economics of bioenergy and emissions trading.
(2012-06) Moon, Jin-Young
The three essays in this dissertation focus on the economics of bioenergy and emissions trading. Chapter Two analyzes the economic impacts of cellulosic feedstock production in a major watershed of south-central Minnesota. A regional economic model of agricultural production in the watershed is constructed. By integrating environmental parameters from a biophysical simulation analysis of the watershed, the model focuses on economic and environmental issues associated with increasing use of two cellulosic feedstocks, corn stover and switchgrass, at the watershed level. Results indicate that corn stover can be produced at a relatively low marginal cost compared to switchgrass. Sediment and nutrient losses from corn stover production make switchgrass more promising on environmental grounds but the high marginal cost of production causes switchgrass to cover only small part of crop land if farmers have unrestricted choice about how to supply cellulosic feedstocks. Chapter Three extends the model of chapter Two to examine the tradeoffs between cellulosic feedstock production and water quality by analyzing policy options targeted to address those tradeoffs. Policy alternatives considered include restrictions on total nitrate-N load in the watershed and production subsidies for switchgrass – an energy crop with potential environmental benefits. Restricting nitrate-N loads increases the cost of cellulosic feedstock supply and in some circumstances makes switchgrass production an economical alternative. Switchgrass production subsidies, if sufficiently high can increase feedstock supply while reducing or eliminating the negative effects of feedstock production on water quality. Chapter Four examines how uncertainty in emissions affects firms’ decision of permit purchase and abatement. This paper extends previous models of emissions trading by considering uncertainty as well as the order of firms’ decisions about abatement and permit trading. When there is uncertainty about emissions, total expected emissions are the same regardless of the order of moves. The results show that whether firms abate more under uncertainty is dependent on the expected penalty cost and marginal abatement cost. If the expected marginal penalty cost is greater than the marginal abatement cost, the firm will choose to reduce emissions and abate more under uncertainty. When expected penalty is greater than marginal cost of abatement, increase in uncertainty makes expected emissions decrease given unit penalty fee.
Influence of Water Chemistry and Microbiome on Macrophyte Composition in Wild Rice Wetlands in NE Minnesota
(2022-12) Untiedt, Tyler
Abstract Wild rice (Zizania palustris) has significant cultural and ecological value in Minnesota and is the state grain. Over recent decades, a decline in wild rice abundance and distribution in the region has occurred due to environmental contamination, opportunistic species infestation, and habitat destruction. Considerable resources and effort have been invested in managing and restoring wild rice wetlands to improve wildlife habitat and opportunities for wild rice harvest. Monitoring these restoration efforts is essential to refine and optimize restoration practices. We hypothesize that changes in surface and porewater chemistry, as well as the water column microbial community in wild rice beds, affect the establishment of self-sustaining wild rice populations. Microbe-plant interactions are critical to nutrient uptake and greatly impact the fitness of aquatic macrophytes. Little investigation has been done on the environmental microbiome of wetlands in the NE Minnesota region. This study aims to characterize the bacterial community associated with the water column naturally occurring wild rice beds along with water quality and macrophyte taxa diversity. Study sites include wetlands with the presence of; self-sustaining wild rice, historical wild rice restoration activity (with and without success), and current restoration. Using a high throughput amplicon sequencing approach, we provide a holistic view of microorganisms associated water columns of wild rice wetlands, as well as wetlands dominated by competing vegetation. These results improve our understanding of microbial ecology in wild rice wetlands in Minnesota, which may be helpful in developing management strategies that promote restoration success.
Investigating Bi-directional Impacts of the Microbiome and Drinking Water Quality in Drinking Water Distribution System Water Mains and Storage Facilities
(2022-07) Gomez, Christa Kimloi
The microbial communities that live in the biofilms of drinking water distribution system (DWDS) environments can exert significant impacts on drinking water quality before it reaches the consumer. The relatively recent advent and accessibility of powerful culture-independent techniques, such as high-throughput sequencing, have enabled characterization of diverse microbial communities; however, the difficulties of accessing DWDS infrastructure has hindered many efforts to study the health-relevant DWDS microbiome. In this work, high-throughput sequencing and quantitative real-time polymerase chain reaction (PCR) techniques were leveraged to characterize the biofilm communities of simulated and full-scale water mains, as well as the in situ suspended and biofilm communities of elevated water storage towers and underground reservoirs in a chloraminated DWDS. Seasonal variability and drivers of community composition were assessed in the simulated DWDS biofilms and in full-scale drinking water storage facilities. Among other examined drivers of community, the presence and concentration of disinfectant was an important selective pressure that impacted community composition. Communities in the simulated and full-scale DWDS biofilms were generally dominated by bacteria that live preferentially in, and form biofilms, exhibit increased resistance to disinfectant concentrations, or display versatility in substrate-utilization. These included genera that contain opportunistic pathogens, such as Mycobacterium, Pseudomonas, and Stenotrophomonas, genera implicated in microbiologically-caused corrosion of infrastructure (sulfate-reducing Desulfovibrio), - as well as ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) that catalyze nitrification processes and can cause reoccurring, problematic decreases in chloramine residual concentrations. Species-level taxonomic resolution of DWDS Mycobacterium, achieved by sequencing a mycobacterial heat shock protein gene, indicated that the bulk of these bacteria were not disease-associated strains. Early stages of community succession occurred rapidly for biofilms on new surfaces that were in proximity to more established biofilms – within a month, the biofilms on new surfaces exhibited similar compositions to neighboring, older biofilms. Apart from early changes in composition indicative of an initialization stage, biofilm communities in water storage facilities were temporally stable, although somewhat spatially heterogeneous. In contrast, suspended communities showed seasonal changes and were heavily influenced by water chemistry. Additionally, suspended communities were spatially homogeneous within a facility, and even at different facilities within the DWDS. In storage facilities that experienced problematic nitrification episodes and decreases in chloramine concentrations, suspended AOB concentrations increased as chloramine concentrations decreased. Notably, decreases in disinfectant were not accompanied by increases in the growth of other bacteria. Rather, as AOB concentrations increased, the total biomass of suspended communities actually decreased. During nitrification events, biofilm and suspended community compositions were most similar, lending further support to the concept that biofilms may act as reservoirs for nuisance and pathogenic bacteria in the DWDS. Abundant taxa were consistent with other studies of DWDSs that maintain chloramine, which provided support for the applicability of these findings to other systems, especially as there are no studies to compare to, to-date, of the microbiome in elevated storage towers.
Monitoring Phytoplankton Biomass and Surface Temperatures of Small Inland Lakes by Multispectral and Thermal UAS Imagery
(2021-08) Bartelt, Garrett
Chlorophyll-a is an essential environmental indicator for water quality monitoring, as it is used in photosynthesis by all phytoplankton. Chlorophyll-a concentration in water is correlated to phytoplankton biomass, which is used to monitor harmful algal blooms (HABs). The eutrophication of waters observed during HABs can deplete the water of dissolved oxygen, smother aquatic vegetation, and some species can even release cyanotoxins into the environment. Nutrient pollution and warmer waters caused by climate change are expected to increase the intensity and frequency of HABs. Remote sensing chlorophyll-a concentration for HAB monitoring has been demonstrated with satellite imagery. Satellites effectively monitor temperatures and large algal blooms in oceans and large lakes but lack the spatial resolution to monitor small bodies of water effectively. This study aims to apply remote sensing techniques to multispectral and thermal images captured by an unmanned aerial system (UAS). A UAS survey was conducted on a small freshwater lake, Brownie Lake, in Minneapolis, Minnesota. The collected imagery was then correlated to in-situ chlorophyll-a and temperature measurements. Data was collected using the MicaSense Altum sensor. The Altum is a combination multispectral and thermal camera designed for agricultural data collection. While the multispectral camera attachment is not designed for surface water surveys, this study observed good agreement between measured chlorophyll-a concentrations in a small freshwater lake and the UAS multispectral data. Chlorophyll-a concentration was discovered to be highly correlated with the indexes containing the near-infrared (NIR) band, with a wavelength of 840 nm. Of the multispectral indexes evaluated in this study, the most correlated index was the normalized difference vegetative index (NDVI), with an R2 value of 0.80. Remotely determined water surface temperatures also showed a correlation to manually collected water temperatures. This correlation was not as definitive, with an experimental R2 value of 0.31. This research supports the use case for UAS technologies in measuring water quality indicators important to HAB monitoring, such as temperature and chlorophyll-a concentration.
Nearfield water quality of the Metro WWTP effluent mixing zone in the Mississippi River under Summer conditions
(1984-08) Stefan, Heinz G.; Farrell, Gerard J.; Yuling, Chen
A side channel discharge such as that from the Metro Wastewater Treatment Plant (WWTP) into the Mississippi River interacts with the river flow in several ways before the two become fully mixed. Among the flow and mixing processes generally to be considered are: (a) Jet effects due to the momentum of the discharge. (b) Lateral displacement of river flow by the effluent input. Conservation of mass requires that the streamlines in the river are displaced towards the center to make room for the effluent flow rate in the river. (c) Downstream advection by the river flow. (d) Transverse turbulent mixing due to bed shear and secondary flow in the river. (e) Buoyant spreading caused by the density difference between effluent water and river water. The density depends on water temperature and total solids content. (f) Vertical turbulent mixing by the river due to bed shear. (g) Mixing by tug boats and barge traffic.
Novel Best Management Practices for Improving Water Quality in Midwestern Agricultural Settings: Field and Lab Applications
(2018-02) Krider, Lori
Water quality in agricultural watersheds is under greater scrutiny as the landscape and hydrologic pathways are altered to increase the production of affordable food. Agricultural best management practices (BMPs) are common tools to improve water quality on a local scale. This study examined the effectiveness of two-stage ditches using field data and the efficacy of bioreactors in a lab setting. In the field, the physical stability and nitrate removal of an alternatively designed drainage ditch in southern Minnesota (the Mullenbach Two-Stage Ditch) were assessed. Two-stage ditches are more stable than traditional, trapezoidal designs and may adjust slightly overtime to produce the most sustainable shape. This BMP is also effective at removing nitrate, although variably as it relates to temperature, hydraulic residence time, and influent nitrate loading. In the lab, a system to determine nitrate removal under reduced temperature conditions was used to evaluate novel media for bioreactors, including walnut shell biochar and BrotexTM material. A flow characterization and nitrate removal model was created in MS ExcelTM. Additionally, the model incorporated microbial processes found by a quantitative polymerase chain reaction (qPCR). This design is 2X more effective than traditional, woodchip only configurations. Multi-media bioreactors may have great potential for future applications by enhancing nitrate removal and microbial activity. Constant innovation is the key to sustainability, which can be achieved by creating optimized systems that highly effective under a range of environmental conditions and scenarios.
Soil Properties, Hydrology, and Water Quality of Perennial Vegetation on Undisturbed Soil in Southwestern Minnesota
(2016-05) Tollefson, David
This field experiment examined soil properties including bulk density, infiltration, and hydraulic conductivity, and the hydrology and water quality of three small watersheds composed of perennial vegetation with no history of soil disturbance (tillage). After two years, one of the watersheds was converted to row crop production. A fourth agricultural reference watershed with a long history of row crop production was also monitored. The perennial vegetation on undisturbed soils had much lower bulk density and higher infiltration and hydraulic conductivity rates than the newly converted and reference row crop fields. Soil properties were significantly changed in the first two years after conversion. Runoff did not occur from the perennial vegetation on undisturbed soils under non-frozen soil conditions, however, runoff did occur from the row crop fields in June. The perennial vegetation reduced runoff volumes, and had lower nutrient and sediment yields compared to the row crop.
The Timing of Winter Application of Dairy Manure and its Placement Within the Snowpack Affect Nutrient Loading to Snowmelt Runoff
(2022-03) Allen, Luis
Runoff from agricultural fields can contribute to the degradation of surface waters when not adequately controlled. Application of manure in the winter is practiced in the upper Midwest of the USA, where seasonally frozen soils reduce or eliminate infiltration from precipitation events and can result in greater nutrient losses from overland runoff. While extensive research exists on the hydrological conditions that interact with manure nutrient losses from runoff during spring, summer, and fall, winter manure best management practices need further investigation. Further research is also needed due to the changing hydrological conditions from the effects of climate change, such as the increased number of freeze-thaw cycles and the shortening of the snowfall period during the winter season. Two studies evaluated whether the timing of winter manure application and its placement within the snowpack affect the nutrient content and loading of snowmelt runoff. In the first study, two dairy manure application timings were assessed under field conditions: early manure (applied in December or January and over frozen soils in the absence of snow) and late manure (applied in February or March and over a snowpack). In the second study, three manure placements were assessed within a 30-cm snow column under laboratory-based conditions: manure under snow (US), manure between snow (Mid), and manure over snow (OS). The timing of winter manure application showed a statistically significant lower nutrient loading to snowmelt runoff from the early manure treatment, regardless of the hydrological and climatic variations between years. Manure placement within the snowpack showed a significant treatment effect on nutrient loading for nitrate-N, ammonium-N, and dissolved reactive phosphorus. A significant placement treatment effect was not observed for total nitrogen (bound), total phosphorus, dissolved carbon, and dissolved organic carbon. These studies suggest that while nutrient loading to snowmelt runoff may be reduced, results may vary depending on hydrological conditions and the type of nutrient studied. This research may inform winter manure and water quality best management practices. Producers may better assess the timing of manure application to reduce nutrient losses. Goals can also be assessed depending on the nutrient of concern.
Water Quality Benefits of a MN Floodwater Storage Impoundment
(2017-09) Guzner, Mariya
Nutrient and sediment pollution in Lake Winnipeg and its watershed, the Red River Basin, MN, are degrading water quality and impairing aquatic health, fishability, swimmability and recreational potential. It is necessary to capture and store the pollutants phosphorus (P), nitrogen (N), and total suspended solids (TSS) on the landscape, to improve water quality and protect valuable water resources in the region. Floodwater storage impoundments have the potential to effectively capture and store nutrient pollutants and suspended sediments, and consequently improve downstream water quality. There are already several dozen similar impoundments in the state, and plans to build approximately 200 in total. The water quality benefits of a floodwater storage impoundment in the Red River Basin were tested through various methods in this study. Nutrient budgets were built for the impoundment in 2014, 2015, and 2016. Load and concentration reductions were calculated for water entering and leaving the system, for nitrogen, phosphorus, and total suspended solids. In 2016, nitrogen and phosphorus reductions of 73% and 66%, respectively, were achieved. A hypothetical load reduction calculation was also modeled to determine the effects of impoundment water release speed on pollutant capture. The soil phosphorus storage potential of the impoundment was determined through a laboratory sorption experiment. Soils at the site were analyzed for their linear adsorption coefficient (K) and equilibrium P concentration at zero-sorption (EPC0). Analysis compared soils under various land uses, including: cropped, planted with native vegetation, and flooded. Results suggest that all soils within the impoundment outperform soils at the exterior of the structure regarding phosphorus storage and buffering potential. Variation in soil-phosphorus sorption properties between sites with different vegetation types will advise cropping and planting plans to optimize water quality benefits. Results of this research are intended to advise management of the study site, similar impoundments, and constructed wetlands for water quality treatment.

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