Journal of Contemporary Water Research & Education最新文献

Permeable pavements are a green infrastructure stormwater management practice that can serve as a functional component of the site design. However, previous field studies suggest high uncertainty in the parameters used for performing hydrologic calculations for permeable pavements. The Environmental Protection Agency (EPA) Storm Water Management Model (SWMM) within the PCSWMM software package was used to simulate the hydrologic dynamics of a parking lot that is 25% covered with permeable interlocking concrete pavers in Auburn, AL. The model was calibrated to field observations of water level at two points where the pavement system outflows to a bioretention basin and rainfall data from a nearby weather station. The use of the Curve Number (CN) method within SWMM resulted in good prediction of pavement outflow by the calibrated model, with R² and Nash-Sutcliffe model efficiency both greater than 0.8, except where issues with precipitation data coverage occurred. This demonstrates that permeable pavements can be modeled as a land cover type rather than as detention storage. The calibrated value of the runoff CN for permeable pavement was 60, much lower than what is recommended in many design guidelines for the underlying soil type at the research site, which is hydrologic soil group B. Based on evaluation of alternative model scenarios, the permeable pavement reduced runoff by 11-38% across contrasting rain events.

In the United States, the lack of diversity, equity, inclusion, and justice (DEIJ) in water governance and management has been identified as a serious problem that affects the validity of decisions. Because water governance and management institutions, processes, and practices at all scales involve dialogue, it is important to understand DEIJ in water dialogues. This paper reports on the results of a systematic literature survey that was undertaken to guide efforts by The University of Arizona Water Resources Research Center to improve diversity and inclusion in its engagement practices and outreach strategies. Three questions are explored: 1) How is DEIJ defined, conceptualized, and measured in water dialogues?, 2) How does a lack of DEIJ in water dialogues affect water-related outcomes and actors?, and 3) What are the approaches that can be used to increase DEIJ in water dialogues, especially with respect to underrepresented groups? The review synthesizes definitions of DEIJ and examines theories and methods from the literatures on discourse, diversity, social learning, and environmental justice. The lens of dialogue focused these disparate literatures on how people with diverse voices can be engaged and enabled to effectively participate in water dialogues. Despite the paucity of DEIJ literature relating to water resources in general, and to water dialogues more specifically, the review identified characteristics of DEIJ, factors that contribute to DEIJ issues, general lessons, and pathways that apply to increasing DEIJ in water dialogue participation. Further, this paper articulates a conceptual framework for understanding and addressing DEIJ failures in water dialogues. A concept of “just water dialogues” emerged that integrates insights from the literature reviewed with notions of environmental justice to help with identifying and resolving “water dialogue justice” (i.e., DEIJ failures). Review results suggest that DEIJ in water resources dialogues depends on the distribution of knowledge resources, and on broader issues that include cultural, political, and other often ignored contextual factors. Importantly, addressing DEIJ problems through the creation and maintenance of just water dialogues requires tackling power imbalances, enhancing individual and organizational capacity, and building bridges through effective engagement of diverse voices, especially those of underrepresented groups. Strategies that have demonstrated effectiveness in other contexts are highlighted, and future research needed to improve practices to enhance DEIJ in water dialogues is outlined.

Fecal indicator bacteria, Escherichia coli, for primary body contact recreation (PBCR) in Oklahoma waterbodies, is defined as the geometric mean of 10 samples from the recreation season, May 1 to September 30, with an impairment threshold of 126 colony forming units (cfu) per 100 mL. However, the water quality standards provide limited guidance on spatiotemporal and environmental factors that could influence samples collected and analyzed. In this study, two stream cross sections under baseflow conditions in a central Oklahoma urban perennial stream, Spring Creek, were densely sampled to investigate temporal and spatial variability of E. coli concentrations and water quality parameters across the stream channel. Water quality parameters (specific conductivity, temperature, dissolved oxygen, pH, turbidity, and total suspended solids (TSS)), stream discharge, and bacteria samples were collected simultaneously at equal intervals across the two cross sections in the morning and afternoon during one summer day with sunny, dry, and hot weather conditions. Results indicate a significant difference between time-of-day samples and water quality parameters and E. coli concentrations. Strong correlations between temperature, dissolved oxygen, and time versus E. coli concentrations were observed, while location, turbidity, and TSS were not significant or correlated to measured values. Furthermore, E. coli concentrations were highly variable spatially across each stream cross section, regardless of time of day or location. Results from this study provide an initial indication that stream water quality, spatial cross section sample location, and diurnal variations may be influencing factors on bacteria concentrations.

The micronutrient iron has been noted to play a crucial role in regulating phytoplankton growth; however, most studies have focused on large lakes with persistent phytoplankton blooms that are known to undergo iron limitation, such as Lake Erie. Iron abundance in boreal lakes is also known to correlate with dissolved organic carbon and increased iron concentrations causing “browning.” To assess the spatial distribution of dissolved Fe (DFe) in lakes throughout Iowa, a landscape once dominated by prairies, DFe was measured in surface waters of 124 lakes distributed across the state over the 2018 summer season. Thirty lakes were selected for 15 weeks of weekly DFe monitoring to assess temporal trends over the summer season. Dissolved Fe concentrations in surface waters ranged from 5 to 1000 μg L^-1. Iowan lakes exhibited temporal trends in DFe, with decreasing concentrations from May to mid-July and an increase into August. Unsupervised learning method (k-means) identified three main groups of lakes based on temporal DFe trends. In this study, surface water temperature was associated with DFe trends in some lakes. This study serves as a baseline for DFe in Iowa’s lakes and can provide insights into iron biogeochemical cycling and its role in phytoplankton blooms, which are important to ecosystem and public health.

Harmful Algal Blooms (HABs) persist in many water bodies around the world and pose adverse health and economic impacts to the affected communities. Small Unmanned Aerial Vehicles (UAVs) have recently been applied as a cost-effective tool for HABs monitoring. In this study, HABs in two small lakes in Southern Illinois (Carbondale Reservoir and the Campus Lake of Southern Illinois University) were monitored using UAVs and biomass concentrations in lake waters. By analyzing vegetation indices derived from multispectral UAV images and chlorophyll-a concentrations in the two lakes, statistical regression models were established for each waterbody. The model relates spectral characteristics of the lake water to its algae biomass. It was found that normalized difference vegetation index (NDVI) and blue-to-green band ratio are the best-fit indices to the variation in chlorophyll-a in Carbondale Reservoir and the Campus Lake, respectively. The findings in this study can be used for monitoring HABs using UAVs in these lakes in the future.

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.

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.

The watershed group H₂Ozarks 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, H₂Ozarks 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.

Oysters are a foundational part of their ecosystem and research has shown they are negatively impacted by exposure to microplastics (MPs). High MP levels have been documented in waters surrounding oyster reefs, and as filter feeders, oysters can ingest MPs along with their food. Here, we determined MPs (>30 µm) in oysters (Crassostrea virginica) from ten sites across the Mississippi Gulf Coast. Further, a subset of these samples was dissected to quantify MPs within specific tissues. Average concentrations ranged from 30.7± 11.5 to 4.7 ± 0.25 putative MPs/g wet weight (ww) of whole tissue, with sites inside bays near population centers displaying higher levels of MPs than those exposed directly to the Gulf. Mantle, gill, and adductor muscle tissues had similar concentrations of putative MPs (15.9 ± 13.4, 11.5 ± 8.6 and 12.8 ± 6.7 MPs/g, respectively), whereas digestive system tissues had lower concentrations (6.8 ± 6.1 MPs/g of tissue). This suggests that most MPs in an oyster likely adhere to external tissues and are not actually ingested. Most of the MPs retained were in the smallest size fraction of 30-90 µm (80%), followed by 125-250 µm (9%), 90-125 µm (8%), and >250 µm (3%). Analysis of samples from Biloxi Bay by µ-FTIR to assess MP composition shows that polyurethane, polyethylene, and polyamide are common, but additional analyses are needed to fully characterize the MP profile across sites. Overall, this work provides much-needed empirical data on the abundances and sizes of MPs in oysters from the Mississippi Sound, as well as the tissues where they reside.