The United States invests billions of dollars annually to perform stream restoration projects, yet few studies have investigated the effects this ecosystem manipulation has on nutrient cycling and associated water quality. Water quality improvement remains a substantial motivation for mitigating catchment-scale disturbances, especially in urban streams. Various urban land use practices impact the transfer and transport of nutrients such as soluble reactive phosphorus, ammonium, and nitrate plus nitrite from land into the streams and rivers. The uptake length (Sw), or the distance a dissolved nutrient travels downstream within a stream reach, can be measured using short-term nutrient injections, where shorter uptake lengths suggest greater nutrient retention. This study evaluated the efficacy of using nutrient injection experiments as a monitoring tool to assess nutrient retention efficiency in first-order urban restored (RES) and urban unrestored (URE) stream reaches within the Piedmont ecoregion of South Carolina during the winter and summer seasons of 2022. Results suggested that the lack of fine sediment, such as silt and clay, may affect the nutrient cycling of phosphorus. The total nitrogen:total phosphorus ratio indicated the stream was phosphorus-limited during the experiments. The mean soluble reactive phosphorus uptake length throughout the study was shorter in RES than URE, suggesting that the restored reach was more efficient in retaining dissolved phosphorus. During summer injection, RES observed the shortest soluble reactive phosphorus uptake length of 77 m, while URE marked the longest uptake length of 3059 m during the same period. However, during winter injections, the URE segment had both the shortest and longest uptake lengths. In summer, RES exhibited noticeably shorter ammonium uptake lengths, while ammonium uptake lengths could not be calculated in URE. The presence of engineered pools in RES assisted in nutrient dynamics and helped trap nutrients, particularly soluble reactive phosphorus and ammonium, and could be prioritized in stream restoration efforts. Preliminary results from this study could provide helpful insights into the effectiveness of stream restoration and in-stream structures on nutrient dynamics, although further research is needed.

Since 1901, heavy rainfall events have increased in the United States in both intensity and frequency, and human population in the United States has increased, resulting in significant land use changes. Both trends contribute to an increase in observed flood magnitude and frequency. To determine if a relationship exists between land use/land cover and changing stream flows in northwest Arkansas, this study analyzed temporal changes in various flow statistics for 14 stream gages and compared the rates of change in flow statistics from gages on streams with watersheds that have varying land uses, i.e., urban, agricultural, and undeveloped. Mann-Kendall analysis was used to determine statistically significant changes in flow statistics, which were then compared to National Land Cover Dataset (NLCD) watershed land uses from 2001 and 2019. All analyzed gages had one or more flow statistics with at least a moderately significant increase, and all analyzed flow statistics showed at least moderately significant streamflow increases at two or more gages (P < 0.100). There were no decreases of any significance in any flow statistic at any gage. In general, urban land development did not happen on native prairies and forests but on previously agricultural land. Significant positive relationships were found between maximum yearly flow and 2019 urban land use, urban land use change from 2001 to 2019, and 2019 Human Development Index (HDI). A similar relationship was found to exist between yearly minimum flow and 2019 HDI. These results highlight the importance of considering the cost of potential stream bank erosion and flooding in future land use planning, permitting, and zoning.

The study involves prediction of chlorophyll-a as HABs index using different machine learning models.

Highlights Phosphorus fluxes were quantified before and after alum treatments five times between 2014 and 2019. Phosphorus fluxes were not significantly different from baseline after five treatments spread over six years. Long-term effectiveness of alum treatments was reduced due to large external phosphorus loads. Abstract. This study quantified sediment P fluxes under aerobic and anaerobic conditions at Quarry Island Cove at Lake Wister, Oklahoma, before and after alum treatments, which occurred five times between 2014 and 2019. Sediment-water cores were collected from the cove and incubated for 10 days at room temperature under aerobic and anaerobic conditions, and P fluxes were estimated as the slope of the increase in P mass over time divided by the area of the core. Aerobic P fluxes were not significantly different before or after alum treatments. Under anaerobic conditions, P fluxes significantly decreased one week after alum treatments compared to a week before treatment. However, after five treatments across six years, sediment P fluxes under anaerobic conditions were not significantly different than prior to any alum treatments in 2010 and 2014 (3 to 4 mg m-2 day-1). The lack of overall improvement in anaerobic P fluxes over time is likely due to the magnitude of P and sediment loads entering Lake Wister from the watershed, where 92% of the total P load to Lake Wister from 2010 to 2020 was from external sources. Therefore, while alum treatments provide short-term reductions in P fluxes, external P sources must be addressed. Keywords: Aluminum sulfate, Lake management, Nutrient loads, Phosphorus.

Highlights Machine Learning (ML) models are identified, reviewed, and analyzed for HAB predictions. Data preprocessing is vital for efficient ML model development. ML models for toxin production and monitoring are limited. Abstract. Harmful algal blooms (HABs) are detrimental to livestock, humans, pets, the environment, and the global economy, which calls for a robust approach to their management. While process-based models can inform practitioners about HAB enabling conditions, they have inherent limitations in accurately predicting harmful algal blooms. To address these limitations, Machine Learning (ML) models can potentially leverage large volumes of IoT data to aid in near real-time predictions. ML models have evolved as efficient tools for understanding patterns and relationships between water quality parameters and HAB expansion. This review describes ML models currently used for predicting and forecasting HABs in freshwater ecosystems and presents model structures and their application for predicting algal parameters and related toxins. The review revealed that regression trees, random forest, Artificial Neural Network (ANN), Support Vector Regression (SVR), Long Short-Term Memory (LSTM), and Gated Recurrent Unit (GRU) are the most frequently used models for HABs monitoring. This review shows ML models' prowess in identifying significant variables influencing algal growth, HAB drivers, and multistep HAB prediction. Hybrid models also improve the prediction of algal-related parameters through improved optimization techniques and variable selection algorithms. While ML models often focus on algal biomass prediction, few studies apply ML models for toxin monitoring and prediction. This limitation can be associated with a lack of high-frequency toxin datasets for model development, and exploring this domain is encouraged. This review serves as a guide for policymakers and researchers to implement ML models for HAB prediction and reveals the potential of ML models for decision support and early prediction for HAB management. Keywords: Cyanobacteria, Freshwater, Harmful algal blooms, Machine learning, Water quality.

Highlights Despite little to no dissolved nutrient supply in surface water, harmful algal blooms are sustained throughout the 2020 growing season. Sediment phosphorus release was high in a lake that has annual harmful algal blooms, and it is an important piece of the watershed management puzzle. Thresholds and hierarchical structure with individual physicochemical properties and pigment fluorescence at this lake explain a large portion of microcystin variability. Abstract. Harmful algal blooms (HABs) in freshwaters are a global concern, and research has focused on the nutrient drivers of cyanobacterial growth and toxin production. We explored the importance of nutrients on sustained cyanobacterial HABs producing measurable microcystin at Lake Fayetteville, Arkansas, USA. The specific objectives were to (1) quantify sediment phosphorus (P) flux and estimate potential equilibrium P concentrations (EPC0) in July 2020, (2) assess water quality conditions in the lake from March through September 2020, and (3) evaluate physicochemical thresholds (or change points, CPs) and hierarchical structure with total microcystin concentrations. The sediments were a potential P source under both oxic and anoxic conditions, and the SRP concentrations in the lake water were continuously less than the EPC0 estimated for bottom sediment (~0.03 mg L-1); sediments are likely a potential P source for cyanobacterial HABs at Lake Fayetteville. The physicochemical changes at Lake Fayetteville over the 2020 growing season were typical of small, hypereutrophic reservoirs, with low biomass in winter when nutrient supply was greatest and the greatest cyanobacterial growth and microcystin toxin as nutrient supply diminished into the growing season. Microcystin concentrations were elevated above 1 µg L-1 from mid-June through mid-August 2020, and most physicochemical parameters in this study showed thresholds or change points with microcystin. Hierarchical structure existed with total microcystin concentrations, showing the potential importance of cyanobacterial biomass, N supply, and total P on elevated microcystin. Nutrients and algal pigment raw fluorescence explained 83% of the variation in total microcystin concentrations at Lake Fayetteville during the 2020 growing season. Nutrients (both N and P) from external and internal sources are likely important drivers of these blooms and toxicity at Lake Fayetteville. Keywords: Harmful Algal Blooms, Nutrient Drivers, Sediment Phosphorus Release, Water Quality.

Cyanobacterial harmful algal blooms (cyanoHABs) have been observed across the USA and worldwide, and even locally in Lake Fayetteville (Arkansas, USA) once we started monitoring for total microcystin. The goal of this research note was to present a framework that might help guide cyanoHAB and toxin public health advisories at Lake Fayetteville. We evaluated nonparametric change points (i.e., thresholds) and hierarchical structure (using classification and regression trees) between total microcystin concentrations, chlorophyll, and phycocyanin; chlorophyll-a is a pigment in all algae, while phycocyanin is specific to cyanobacteria. Pigment concentrations and raw fluorescence units (RFUs) all showed significant thresholds with total microcystin concentrations, basically showing that as concentration or RFUs increased above the thresholds that total microcystin was greater at Lake Fayetteville. The regression tree with total microcystin concentrations showed a first split with phycocyanin RFUs at 4524, and then when phycocyanin RFUs were greater there was an optimal range for the phycocyanin to chlorophyll RFU ratio (0.64-1.5). At this recreational lake, total microcystin concentrations were greatest when water samples met these criteria, providing a possible framework for when lake managers might suggest an increased risk for elevated cyanobacterial toxins.

Cyanobacterial harmful algal blooms (cyanoHABs) continue to be a monitoring and research focus, particularly on the occurrence of toxins like total microcystins. The objectives of this study were to evaluate sampling and analytical variability in measured total microcystin concentrations and then to evaluate the volume of raw water needed in the freeze thaw cycle to reduce sampling variability. Water samples were collected from a recreational lake with annual cyanoHABs, and then 2 mL was used in freeze thaw cycles before total microcystin analysis. Then, sample volumes used in the freeze thaw cycles varied from 2 to 300 mL for total microcystin analysis. With three separate experiments, we observed a great deal of sampling variability (when using 2 mL in the freeze thaw cycles) while analytical variability was much less. In fact, sampling variability could potentially account for temporal variability observed in the routine monitoring. However, when sample volume used in the freeze thaw cycles increased, total microcystin variability decreased. We recommend at least 20 mL to be used in the freeze thaw cycles when analyzing total microcystins in environmental samples.

The watershed group H(2)Ozarks founded the StreamSmart Citizen Science Program to establish baseline and long-term water quality data for the Upper White River Basin, Arkansas. StreamSmart volunteers collect water samples and conduct habitat and macroinvertebrate community assessments at >20 sites across a land use-land cover (LULC) gradient. Since 2020, H(2)Ozarks has adaptively assessed the program to ensure that the investment in water quality data meets core goals, with particular interest in planning tools and aligning expectations of volunteer effort with the level of training and support. Study objectives were to use StreamSmart data to 1) facilitate understanding of water quality response to stressors in the basin using a range of methods (Spearman rank correlation, non-parametric changepoint analysis, and categorical and regression tree analysis) and 2) explore implications for program design and watershed planning. Water chemistry-LULC relationships were in-line with prior regional studies, as well as global patterns. Detected thresholds and hierarchy provide potential targets for managing LULC change to protect water quality, but further analysis is warranted to refine these relationships. Macroinvertebrate stressor-response was most detectable for sensitive and less sensitive taxa and for habitat index components, suggesting potential to streamline these programmatic elements. Study findings for StreamSmart should also be informative for other small-scale volunteer monitoring programs with limited resources, but which actively evaluate the types of data and program activities that yield a maximum scientific return on investment.

Trend analyses of water quality seek to determine whether concentrations of constituents have increased or decreased over time, which can show the effectiveness of management practices or the need for pollutant reduction. The Poteau River watershed (PRW) is a transboundary watershed across Arkansas and Oklahoma and, in Arkansas, has been listed as a priority watershed within the Arkansas Nonpoint Source Pollution Plan since 1998. The Poteau River, Black Fork, and Fourche Maline within the PRW flow into Lake Wister, which is an important reservoir for recreation, fishing, and waterfowl hunting for residents and tourists around eastern Oklahoma. The purpose of this study was to analyze long-term concentration trends and loads on the major tributaries entering Lake Wister using the Weighted Regression on Time, Discharge, and Season (WRTDS). The largest magnitude of loads came from the Poteau River, but flow normalized (FN) P and sediments have decreased over time, which is a positive impact of watershed management and must be maintained. However, FN N on the Poteau River has increased over time and should be the focus of future management on the Poteau River. Although the magnitude of constituent loads from the Fourche Maline is less than from the Poteau River, increasing FN P is a concern and should be prioritized for management in Oklahoma. The relatively undisturbed Black Fork watershed contributes the smallest loads to Lake Wister, and FN concentrations are decreasing or not changing over time, suggesting a low priority for the Black Fork watershed.

HighlightsA HOBO water level logger was deployed to obtain a continuous stage record across sites.SonTek-IQ acoustic Doppler instruments were deployed to measure discharge during high-flow events.Rating curves were developed using linear regression, LOESS regression, and Manning’s equation.The proposed method provides an opportunity to collect continuous flow records across multiple, small-scale watersheds.Abstract. Discharge monitoring stations are often costly and difficult to install, operate, and maintain, especially in small streams. The purpose of this study was to evaluate a low-cost method for remotely monitoring streamflow in small-scale watersheds to provide continuous discharge measurements across multiple sites and flow conditions. Within the Upper Poteau River Watershed (UPRW) in Arkansas, 12 sites were selected at bridge crossings near the outflow of HUC-12 or HUC-14 subwatersheds. A HOBO water level logger was deployed at each site to obtain continuous stage records, and HOBO barometric pressure transducers were installed within 16 km of each sample site to account for fluctuations in atmospheric pressure. SonTek-IQ acoustic Doppler instruments were deployed to measure discharge during high-flow events, and roving discharge monitoring stations were installed at each site to allow easy rotation of the SonTek-IQ instruments among sites between flood events. Once the roving discharge monitoring stations were installed at each site, one or more SonTek-IQ instruments could be rotated among sites to capture high-flow discharge measurements; therefore, a SonTek-IQ instrument was not required for every site of interest. The high-flow data captured during SonTek-IQ deployment, and baseflow discharge measurements collected on a monthly basis, were used to develop rating curves with a combination of simple linear regression, LOESS regression, and Manning’s equation. The rating curves well represented the measured flows, with Nash-Sutcliffe efficiencies ranging between 0.87 and 0.98. This method provides an opportunity to collect continuous records of flow across multiple, remote, small-scale watersheds, and in conjunction with constituent concentrations and load estimations, can be used to calibrate and validate watershed models. Keywords: Rating curves, Small-scale watersheds, Streamflow monitoring.

HighlightsThe relatively undisturbed Black Fork showed either decreases or no change in flow-adjusted constituents.Water quality was changing at the Poteau River and James Fork, both impacted by point and nonpoint sources.At the James Fork, total P did not change and OP increased, while P decreased at the Poteau River; N increased at both.After shift changes in flow-adjusted concentrations, often no monotonic trends occurred over time.Abstract. Water quality trend analyses seek to determine whether constituent concentrations or loads have increased or decreased over time, which can suggest the effectiveness of management practices or the need for pollutant reduction. The Poteau River watershed (PRW) is a transboundary watershed across Arkansas and Oklahoma, and the Arkansas portion is listed as a priority watershed. The Poteau River flows into Lake Wister, which is an important reservoir for recreation, fishing, and waterfowl hunting in eastern Oklahoma. The purpose of this study was to analyze long-term water quality trends across the upper PRW using the three-step trends method and to determine how water quality has evolved with increasing agriculture and changes in wastewater treatment discharges in Arkansas. The relatively undisturbed river in the PRW, the Black Fork, showed either significant decreases or no change in nutrient and sediment concentrations over time (i.e., ~1.0% year-1 decrease or less). On the other hand, water quality has changed over time in the James Fork and Poteau River watersheds, which are impacted by both point and nonpoint sources. At the James Fork, orthophosphate (OP) significantly increased over time, while total phosphorus (TP) and OP significantly decreased at the Poteau River; total nitrogen (TN) and nitrate plus nitrite (NN) significantly increased at both. Finally, sediment concentrations significantly decreased over time at both the Poteau River and James Fork, with decreasing shifts also occurring in the early 2000s. The changes over time were not necessarily monotonic, as shifts in flow-adjusted concentrations were observed. Effluent concentrations from point sources were found to be decreasing in the 2000s, and regulations were implemented in Arkansas to manage poultry little applications in nutrient surplus areas (i.e., the upper PRW) based on the P index. After those shift changes, water quality was not monotonically changing for most sites and parameters over time. Overall, continued monitoring should be prioritized to ensure that increasing or unchanging trends do not jeopardize water quality in the watershed. Keywords: Point and nonpoint sources, Water quality trends, Watershed management.

In many intensive animal production areas, the over-application of manure has resulted in a build-up of soil phosphorus (P) and the creation of legacy P soils that threaten water quality. We investigated dissolved P forms losses in runoff using simulated rainfall in packed soil boxes amended with three poultry litter and products, including raw (unprocessed) litter, granulated litter with the addition of urea, and heated raw litter. These were applied at 3 kg water-extractable P (WEP) ha-1 as determined with three litter-to-water extraction ratios (1:10, 1:100, and 1:200). Over three simulated rainfall events, the amount of dissolved reactive P (DRP) lost was significantly greater in runoff from soils amended with granulated litter (1.09 +/- 0.02 kg ha-1) than raw (0.81 kg ha-1) and heated (0.58 kg ha-1) litters. No significant differences in the amount of dissolved unreactive P (DUP) in runoff (0.38 +/- 0.07 kg ha-1) were observed among three litter amended soils. The soil test P (i.e., Mehlich 3-P) increased from 6.9 mg kg-1 in control to 10.4-11.6 mg kg-1 in litter amended soils, whereas the total WEP (0.26 +/- 0.03 mg kg -1) in soils was similar after three rainfall simulation events. We conclude that (1) an accurate litter-to-water extraction ratio (>1:200) is critical to determine the amount of WEP in manure as it will ensure similar amounts of soluble P application and will result in identical runoff losses of dissolved P, and (2) the granulation and heating of litter created a product that could enhance the use of poultry litter, especially in non-agricultural markets, resulting in sustainably using manure and reducing the risk of P loss to water bodies.

Abstract Accelerated eutrophication due to human activity has been linked to an increase in the occurrence of cyanobacteria in freshwater systems. The purpose of this study was to document the occurrence of microcystin, a common cyanotoxin, within northwest Arkansas streams. Twenty streams were sampled from May through October 2018, and water and periphyton samples were analyzed for microcystin and chlorophyll‐a (CHL‐a). Mean microcystin concentrations in water samples were low across sites, ranging from < 0.10 to 0.21 μg L−1. Mean microcystin in the periphyton across sites ranged from 2.6 to 9.9 μg m−2 and were within values observed in the literature. All microcystin concentrations measured in these Ozark streams were well below the current USEPA recreational guidelines of 8.0 μg L−1 and the drinking water guidelines of 0.3 μg L−1 for infants and 1.6 μg L−1 for adults.

Abstract Environmental concerns exist over extended storage of liquid animal waste in outdoor holding ponds before land application, particularly in regions with underlying karst geology. To determine the effects of holding ponds on water quality, belowground interceptor trenches, groundwater (well), and a downslope ephemeral stream were monitored for water quality parameters. Nitrate‐nitrogen concentrations increased (p < .0001) in well and ephemeral stream samples but decreased in trench samples (Trench 1 with a p < .0001) near the swine production facility and holding ponds over a 5‐yr monitoring period (April 2014–June 2019). In contrast, chloride, which is a conservative element that can move freely through the soil without chemical, physical, or biological modification, and electrical conductivity decreased (p < .0001 to .0203) over the monitoring period in well and Trench 1 samples. Flow in the interceptor trenches was highly responsive to rainfall, suggesting the trenches were mainly capturing shallow subsurface flows initiated by rainfall. A lack of any increasing trend in chloride and electrical conductivity for ephemeral stream, well, or trench samples suggests that elevated nitrate‐nitrogen concentrations in well and ephemeral stream samples may have been influenced by sources other than the liquid manure holding ponds (i.e., sources that have low chloride and electrical conductivity values). In regions with underlying karst geology, surface and subsurface water resources may require more expansive monitoring to demonstrate liquid manure holding ponds effects on nearby water quality.

Magnetohydrodynamics (MHD) is a unique approach for pumping fluids on a microscale and is highly suitable for enabling multiple functions for chemical analysis on a chip. An ionic current, j, is established in the fluid between selectively-activated electrodes in the presence of a magnetic field, B, that is perpendicular to the current, to generate a force, FB , orthogonal to j and B, through the right hand rule. FB is a body force that propels the liquid in the same direction through momentum transfer. We use microelectrodes, which are patterned into different, individually-addressable geometries on chips. Those electrodes are modified with poly(3,4-ethylenedioxythiophene), PEDOT, a conducting polymer, that converts the applied electronic current in the external circuit to ionic current in the liquid [1] via redox (R) processes and charging. A small NdFeB permanent magnet is placed under the chip to provide B. By strategic activation of the electrodes, fluid flow can be programmed. For example, we previously demonstrated that R-MHD can start, stop, reverse, adjust speed, and alter profiles of the fluid flow. We have also shown recently that R-MHD fluid flow can be diverted in a contactless way by magnetic field gradients when paramagnetic species are present [2]. In our presentation, we will discuss recent studies on using R-MHD to control the paths of individual microvolumes of fluids for different applications, which include chemical separations of mixtures of small biologically-relevant molecules as well as fluorescence imaging [3] and identification of cyanobacteria responsible for algal blooms in fresh water samples. Fluid manipulation and flow profiles under different experimental conditions and solvent and solution compositions will be described. These involve sustained and redirection of flow, adjacent counter flows, transverse paths, sampling, and injection. Acknowledgements: We are grateful for financial support from the National Science Foundation (CMI-1808286) and Arkansas Bioscience Institute, the major research component of the Arkansas Tobacco Settlement Proceeds Act of 2000. References [1] Khan, F. Z.; Fritsch, I. “Chip-Scale Electrodeposition and Analysis of Poly(3,4-ethylenedioxythiophene) (PEDOT) Films for Enhanced and Sustained Microfluidics Using DC-Redox-Magnetohydrodynamics”, Journal of The Electrochemical Society 2019, 166 (13), H615-H627. [2] Hähnel, V.; Khan, F. Z.; Mutschke, G.; Cierpka, C.; Uhlemann, M.; Fritsch, I. “Combining magnetic forces for contactless manipulation of fluids in microelectrode-microfluidic systems:, Scientific Reports 2019, 9:5103. [3] Khan, F. Z.; Hutcheson, J.; Hunter, C. J.; Powless, A. J. Benson, D.; Fritsch, I.*; Muldoon, T. J.* “Redox-Magnetohydrodynamically controlled fluid flow with poly(3,4-ethylenedioxythiophene) (PEDOT) coupled to an epitaxial light sheet confocal microscope for image cytometry applications”, Anal. Chem., 2018, 90(13), 7862-7870.

Harmful algal blooms (HABs) are increasing in magnitude, frequency, and duration caused by anthropogenic factors such as eutrophication and altered climatic regimes. While the concentrations and ratios of nitrogen (N) and phosphorus are correlated with bloom biomass and cyanotoxin production, there is less known about how N forms and micronutrients (MN) interact to regulate HABs and cyanotoxin production. Here, we used two separate approaches to examine how N and MN supply affects cyanobacteria biomass and cyanotoxin production. First, we used a Microcystis laboratory culture to examine how N and MN concentration and N form affected the biomass, particulate N, and microcystin-LR concentration and cell quotas. Then, we monitored the N, iron, molybdenum, and total microcystin concentrations from a hypereutrophic reservoir. From this hypereutrophic reservoir, we performed a community HAB bioassay to examine how N and MN addition affected the biomass, particulate N, and microcystin concentration. Microcystis laboratory cultures grown in high urea and MN conditions produced more biomass, particulate N, and had similar C:N stoichiometry, but lower microcystin-LR concentrations and cell quotas when compared to high nitrate and MN conditions. Our community HAB bioassay revealed no interactions between N concentration and MN addition caused by non-limiting MN background concentrations. Biomass, particulate N, and microcystin concentration increased with N addition. The community HAB amended with MN resulted in greater microcystin-LA concentration compared to non-MN amended community HABs. Our results highlight the complexity of how abiotic variables control biomass and cyanotoxin production in both laboratory cultures of Microcystis and community HABs.

All 54 km of the West Fork of the White River (WFWR) were on Arkansas's 303(d) list of impaired waterbodies for turbidity, total dissolved solids (TDS), and sulfate for many years. This study identifies which river segments fail to meet applicable water quality standards (WQS) and investigates possible anthropogenic or natural sources of pollutants. We also evaluated a larger dataset of 119 sites in the Boston Mountains and Ozark Highlands ecoregions, compiled from the Arkansas Department of Environmental Quality online database. In the WFWR, water samples were collected once or twice a month at nine sites from June 2014 through June 2018. Median values for turbidity, TDS, sulfate, and chloride ranged from 1.8 to 10.8 NTU, 40.8 to 151.3 mg/L, 3.5 to 27.9 mg/L, and 3.2 to 5.5 mg/L, respectively, and generally increased from upstream to downstream (p < 0.05). Violations of the water quality standard for the parameters of interest varied by site, but generally occurred in the downstream portion of the WFWR, where land use, riparian soils, and underlying geology change. In the larger dataset, turbidity, TDS, sulfate, and chloride concentrations were all significantly greater in the Ozark Highlands than the Boston Mountains ecoregion (p < 0.05). Anthropogenic activities influence dissolved ion concentrations across these study sites, while geology and riparian soils may be important factors for differences in sulfate and turbidity.