Assessing watershed-scale impacts of best management practices and elevated atmospheric carbon dioxide concentrations on water yield.

Changes in water yield are influenced by many intersecting biophysical elements, including climate, on-land best management practices, and landcover. Large-scale reductions in water yield may present a significant threat to water supplies globally. Many of these intersecting factors are intercorrelated and confounded, making it challenging to separate the factors' individual contributions to shaping local streamflow dynamics. Comprehensive hydrological models constructed based on a well-established understanding of biophysical processes are often employed to address these matters. However, these models rarely incorporate all relevant factors influencing local hydrological processes, due to the reliance of these models on the latest, albeit limited, state-of-the-art research. For instance, complexities inherent in watershed hydrology, which involve multilayered interactions among potentially many biophysical factors, leave the direct analysis of subtle impacts on water yields measured in-situ largely intractable. Therefore, we propose an innovative approach to assess impacts of elevated atmospheric CO2 concentrations and flow diversion terraces (FDTs) on stream discharge rates at the watershed scale. Initially, we use a comprehensive hydrological model to account for the impacts of major climatic and landuse/landcover factors on changes in field-acquired measurements of water yield. Next, we employ conventional and advanced statistical methods to decompose the residuals of model predictions to facilitate the identification of subtle influences promoted by increases in atmospheric CO2 concentrations and the application of FDTs in an agriculture-dominated watershed. Through this innovative approach, we find that FDTs contributed to a watershed-wide, net water-yield reduction of 188.0 mm (or 28.9 %) from 1992 to 2014. Ongoing increases in ambient CO2 concentrations, which are responsible for an overall reduction in a watershed-level assessment of stomatal conductance, have led to a minor increase in stream discharge rates during the same 23-year period, i.e., 0.45 mm of water yield per year, or 1.6 % overall. Streamflow reductions explicitly caused by regional warming in the area alone, on account of increased evapotranspiration, may be overestimated due to the opposing, synergistic effects on water yield associated with CO2-enrichment of the lower atmosphere and the annual application of FDTs.

Beyond land use planning and ecosystem services assessment with the conservation use potential framework: A study in the Upper Rio das Velhas basin, Brazil.

Human actions can damage the ecosystems and affect the services depending on them, with ample detrimental consequences. In earlier studies, the Conservation Use Potential (PCU) framework proved useful in assessing the capacity for aquifer recharge, suitable land uses and resistance to erosion at the river basin scale. On the other hand, the joint analysis of PCU and land uses allowed identifying the adequacy of current uses in relation to suitability (natural uses) in various basins. This was especially useful from the management perspective in basins with environmental conflicts, where current uses differed from suitability, because the PCU indicated how and where the conflicts should be mitigated. Besides the use as management tool, the PCU has potential to shed light over environmental issues such as ecosystem services, but that was not tempted so far. The aim of this work was therefore to bridge that knowledge gap and frame the PCU's application from the standpoint of Ecosystem Services (ES) assessment. We demonstrated how the PCU could be used to improve provision (recharge), support (sustainable agriculture) and regulation (resistance to erosion) services in a specific basin with land use conflicts (the Upper Rio das Velhas basin, located in Minas Gerais, Brazil), through the planning of suitable uses. It was noted that the studied basin is mostly composed of Very Low, Low and Medium potentials. These classes occur because steep slopes, fragile soils and lithologies with high denudation potential and low nutrient supply dominate in the basin. On the other hand, urban sprawl has a negative impact on all ES, while maintaining agricultural areas with appropriate management can effectively regulate erosion. As per the current results, the premise of using the PCU as joint management-environmental tool was fully accomplished, and is recommended a basis for public policy design and implementation in Brazil and elsewhere.

Temporal change in urban fish biodiversity-Gains, losses, and drivers of change.

Our aim was to examine temporal change in alpha and beta diversity of freshwater fish communities in rivers that have urbanized over the same period to understand the influence of changes in land use and river connectivity on community change. We used biological (2001-2018), land use (2000-2015), and connectivity data (1987-2017) from Toronto, Ontario, Canada. We used linear mixed effects models to determine the strength of upstream land use, connectivity, and their changes over time to explain temporal change in alpha and beta diversity indices. We examined beta diversity using the temporal beta diversity index (TBI) to assess site-specific community change. The TBI was partitioned into gains and losses, and species-specific changes in abundance were assessed using paired t-tests. There were more gains than losses across the study sites as measured by TBI. We found little to no significant differences in species-specific abundances at aggregated spatial scales (study region, watershed, stream order). We found different relationships between landscape and connectivity variables with the biodiversity indices tested; however, almost all estimated confidence intervals overlapped with zero and had low goodness-of-fit. More fish biodiversity gains than losses were found across the study region, as measured by TBI. We found TBI to be a useful indicator of change as it identifies key sites to further investigate. We found two high value TBI sites gained non-native species, and one site shifted from a cool-water to warm-water species dominated community, both of which have management implications. Upstream catchment land use and connectivity had poor explanatory power for change in the measured biodiversity indices. Ultimately, such spatial-temporal datasets are invaluable and can reveal trends in biodiversity useful for environmental management when considering competing interests involved with urban sprawl in the ongoing "Decade on Restoration."

A GIS-based modified PAP/RAC model and Caesium-137 approach for water erosion assessment in the Raouz catchment, Morocco.

Water erosion poses a significant environmental threat in the Mediterranean region, with pronounced impacts observed throughout Morocco. It impairs soil quality and disrupts both sediment transport and water availability. Contributing factors range from natural (climate, topography, and geology) to anthropogenic (land use, vegetation cover, and management). This study introduces an improved Priority Actions Program/Regional Activity Centre (PAP/RAC) model, enriched with GIS and the Caesium-137 (137Cs) technique, to investigate erosion within Morocco's Raouz basin. Enhanced with additional variables including soil types, slope length, rainfall erosion potential, slope orientation, soil moisture, and land surface temperature, the model transcends the classical approach, promoting granularity and precision in predictions. In addition to the comprehensive model, the 137Cs method, which discerns long-term soil erosion and redistribution, provides a dual-faceted validation, bolstering the robustness of this project's erosion risk evaluation. This study's outcomes underscore the gravity of the erosion hazard with significant soil depletion rates ranging from 8.1 to 20 t ha-1 yr-1, demonstrating the model's alignment with empirical data, affirming its utility. The modified PAP/RAC model concurs with the 137Cs data, demonstrating its usefulness for water erosion assessment and management in similar areas.

Remote sensing and GIS-based study of land use/cover dynamics, driving factors, and implications in southern Ethiopia, with special reference to the Legabora watershed.

This paper investigates the trends, drivers, and consequences of LULC changes in Legabora watershed, Ethiopia, by utilizing remote sensing and geographic systems. Landsat Maltispectiral scanner (MSS), Thematic Mapper (TM), Enhanced Thematic Mapper (ETM+), and Operational Land Imager (OLI) images of years 1976, 1991, 2001, and 2022, respectively, were used to study the dynamics of LULC. Essential image pre-processing steps were carefully carried out to correct distortions caused by sensor limitations. Eight main LULC categories were identified based on supervised image categorization methods and the maximum likelihood classification algorithm.The findings of change detection and cross-tabulation matrix demonstrate that there has been a significant increase in the area of cropland 345.1 ha/year, settlement 5.9 ha/year, forest 38.2 ha/year, and degraded lands 2.56 ha/year, respectively, over the period between 1976 and 2022. In contrast, considerable decreases were observed in grasslands (-248 ha/year) and shrublands (-144 ha/year), whereas other LULC categories augmented. The results revealed that the overall accuracy rates stood at 88.3 %, 88.4 %, and 85.6 % for 1976, 1991, and 2022, respectively. The overall kappa coefficient demonstrated values of 0.86 %, 0.86 %, and 0.83 % for the same period. Surveyed respondents perceived population growth, settlement, agricultural expansion, and infrastructure development as the most noticeable drivers of these LULC changes. In contrast, deforestation, land degradation, lack of livestock fodder, and biodiversity loss were identified as the main consequences of LULC changes. The factors and implications addressed in this study may be helpful tool for the formulation and implementation of evidence-based land use policies and strategies within in the study area and elsewhere.

Modeling National Embedded Phosphorus Flows of Corn Ethanol Distillers' Grains to Elucidate Nutrient Reduction Opportunities.

Freshwater quality and ecosystem impairment associated with excess phosphorus (P) loadings have led to federally mandated P reduction for certain organic waste streams. Phosphorus reduction from livestock and poultry feeds such as corn ethanol distillers' grains (DGs) presents a centralized strategy for reducing P loss from animal manurein agriculturally intensive states, but little is known about the actual distribution and geospatial P contributions of DGs as animal feed. Here, a county-level flow network for corn ethanol DGs was simulated in the United States to elucidate opportunities for P reduction and the potential for nutrient trading between centralized sources. Overall, the estimated P in DGs that was transferred to US animal feeding operations was nearly twice that present in all human waste prior to treatment. Simulation results suggest that Midwestern states account for an estimated 63% of domestic DG usage, with 72% utilized within the state of production. County-level data were also used to highlight the potential of using nutrient trading markets to incentivize P recovery from DGs at biorefineries within an agriculturally intensive watershed region in Iowa. In summary, corn ethanol biorefineries represent a key leverage point for sustainable P management at the national and local scales.

River Basin Export Reduction Optimization Support Tool; a tool to screen options for reducing nutrient loads while minimizing cost.

Excess loading of nitrogen and phosphorus to river networks causes environmental harm, but reducing loads from large river basins is difficult and expensive. We develop a new tool, the River Basin Export Reduction Optimization Support Tool (RBEROST) to identify least-cost combinations of management practices that will reduce nutrient loading to target levels in downstream and mid-network waterbodies. We demonstrate the utility of the tool in a case study in the Upper Connecticut River basin in New England, USA. The total project cost of optimized lowest-cost plans ranged from $18.0 million to $41.0 million per year over 15 years depending on user specifications. Plans include both point source and non-point source management practices, and most costs are associated with urban stormwater practices. Adding a 2% margin of safety to loading targets improved estimated probability of success from 37.5% to 99%. The large spatial scale of RBEROST, and the consideration of both point and non-point source contributions of nutrients, makes it well suited as an initial screening tool in watershed planning.

The impacts of human-induced disturbances on spatial and temporal stream water quality variations in mountainous terrain: A case study of Borcka Dam Watershed.

Unaltered watersheds with natural vegetation cover (forest, grasslands, etc.) provide several ecological benefits in addition to providing freshwater, controlling water levels, and supporting flourishing streamside ecosystems. However, as in many watersheds in the World, the research area in this study, the Borcka Dam Watershed (BDW), has been affected by many human-induced disturbances affecting a wide area of forest and grassland areas as well as soil and water resources. Therefore, the objective of this study was to assess and evaluate the possible effects of anthropogenic disturbances, particularly on annual changes in water discharge, some water quality parameters, and total suspended sediment (TSS) amounts in the main streams of four sub-watersheds (Fabrika, Godrahav, Hatila, and Murgul) and the reservoir of the dam. In addition, we intend to confirm that land use change and/or transformation play a significant role in influencing stream water quality. The YSI/Professional-Plus, a portable water quality measurement device, was used to determine the amounts of pH, dissolved oxygen (DO), total dissolved substance (TDS), ammonium (NH4-N), nitrate (NO3-N), salinity, electrical conductivity (EC), and temperature besides measuring discharge and total suspended sediments (TSS) from a total of 27 sampling points in the field. Although the results revealed that the annual mean values of all water quality parameters for all four streams were mostly in good condition, for some time and points of the measurements, several parameters were found to be above the official water quality standards due to the intensive aforementioned anthropogenic activities, particularly in the stream waters of Murgul (e.g. pH and TSS being 10,84 and 236 mg/L, respectively) and Fabrika (e.g. EC of 412 µs/cm; DO of 4.44 mg/L; 14 ml of NO3-N) sub-watersheds. These outcomes indicate that these two sub-watersheds have been impacted more severely by the human-induced disturbances compared to Hatila and Godrahav sub-watersheds.

Enhancing groundwater management using aggregated-data analysis and segmented robust regression: A case study on spatiotemporal changes in water quality.

Groundwater quality management, crucial for ensuring sustainable water resources and public health, is the scope of this study. Our objective is to demonstrate the significance of secondary data analysis for the spatiotemporal characterization of groundwater quality. To this end, we develop and employ a robust trend analysis method, in tandem with a spatiotemporal data aggregation method, to accurately identify shifts in groundwater quality over time, even in the face of inflection points or breakpoints. The methods and results reveal diverse trends and characteristics in water quality over space and time across the entire dataset from selected regions in South Korea, emphasizing the importance of analyzing aggregated data beyond individual business locations. The conclusions indicate that this study contributes to the development of more reliable and effective groundwater quality management strategies by addressing gaps in traditional monitoring methods and the challenges of limited monitoring resources and uneven data quality. Future research directions include the application of the developed methods to other regions and data sources, opening avenues for further advances in groundwater quality management.

Effect of stabilization time and soil chromium concentration on Sesbania virgata growth and metal tolerance.

Sesbania virgata is a pioneer shrub from the Fabaceae family, native to riparian environments in northeast of Argentina, southern of Brazil and Uruguay. In peri-urban riparian soils, metal contamination is a frequent problem, being its bioavailability partly determined by the stabilization time and frequency of contamination events. The effect of time elapsed between chromium (Cr) soil enrichment and plant seeding and Cr doses on S. virgata tolerance and metal absorption were evaluated. Treatments were developed by adding Cr (80-400 ppm) to the soil and allowing two days or fifteen months to elapse before sowing, and a control treatment without Cr addition. After 150 days from seeding, bioaccumulation and translocation factors, growth parameters (dry biomass and its aerial/radical allocation pattern, stem length and its elongation rate), morphological parameters (root volume and leaf area), and physiological parameters (chlorophyll content) of the specimens were determined. The emergence of S. virgata was inhibited since 150 ppm when Cr was added to the soil two days before seeding, with Cr accumulation in roots starting at 80 ppm (17.4 ± 2.5 mg kg-1). Under 15 months of metal stabilization, S. virgata plants survived across the entire range of Cr doses tested, with accumulation in roots since 100 ppm (35.5 ± 0.2 mg kg-1) and metal translocation to aerial tissues only under 400 ppm. The results obtained showed that S. virgata did not have high BCF and TF values, suggesting that it cannot be classified as bioaccumulator of Cr under the tested conditions. However, its presence in environments contaminated with Cr can be beneficial, as it helps to stabilize the metal in the soil.

A Machine Learning Approach to Predict Watershed Health Indices for Sediments and Nutrients at Ungauged Basins.

Effective water quality management and reliable environmental modeling depend on the availability, size, and quality of water quality (WQ) data. Observed stream water quality data are usuallEEy sparse in both time and space. Reconstruction of water quality time series using surrogate variables such as streamflow have been used to evaluate risk metrics such as reliability, resilience, vulnerability, and watershed health (WH) but only at gauged locations. Estimating these indices for ungauged watersheds has not been attempted because of the high-dimensional nature of the potential predictor space. In this study, machine learning (ML) models, namely random forest regression, AdaBoost, gradient boosting machines, and Bayesian ridge regression (along with an ensemble model), were evaluated to predict watershed health and other risk metrics at ungauged hydrologic unit code 10 (HUC-10) basins using watershed attributes, long-term climate data, soil data, land use and land cover data, fertilizer sales data, and geographic information as predictor variables. These ML models were tested over the Upper Mississippi River Basin, the Ohio River Basin, and the Maumee River Basin for water quality constituents such as suspended sediment concentration, nitrogen, and phosphorus. Random forest, AdaBoost, and gradient boosting regressors typically showed a coefficient of determination R2>0.8 for suspended sediment concentration and nitrogen during the testing stage, while the ensemble model exhibited R2>0.95. Watershed health values with respect to suspended sediments and nitrogen predicted by all ML models including the ensemble model were lower for areas with larger agricultural land use, moderate for areas with predominant urban land use, and higher for forested areas; the trained ML models adequately predicted WH in ungauged basins. However, low WH values (with respect to phosphorus) were predicted at some basins in the Upper Mississippi River Basin that had dominant forest land use. Results suggest that the proposed ML models provide robust estimates at ungauged locations when sufficient training data are available for a WQ constituent. ML models may be used as quick screening tools by decision makers and water quality monitoring agencies for identifying critical source areas or hotspots with respect to different water quality constituents, even for ungauged watersheds.

Toxicity and mechanism of nanoplastics to phytoplankton in high-latitude aquatic ecosystems of Canadian prairie: Effects of multiple environmental factors.

The potential ecological risks of nanoplastics (NPs) may be inaccurately assessed in some studies as they fail to consider the impact of environmental factors and their interactive effects. Here, the effects of six representative environmental factors (N, P, salinity, DOM (dissolved organic matter), pH and hardness) on NPs' toxicity and mechanism to microalgae are investigated based on the surface water quality data in Saskatchewan watershed, Canada. Our 10 sets of 26-1 factorial analysis reveal the significant factors and their interactive complexity towards 10 toxic endpoints from cellular and molecular levels. This is the first time to study the toxicity of NPs to microalgae under interacting environmental factors in high-latitude aquatic ecosystems of Canadian prairie. We find that microalgae become more resistant to NPs in N-rich or higher pH environments. Surprisingly, with the increase of N concentration or pH, the inhibitory effect of NPs on microalgae growth even became a promotion effect with the decreased inhibition rate from 10.5 % to -7.1 % or from 4.3 % to -0.9 %, respectively. Synchrotron-based Fourier transform infrared spectromicroscopy analysis reveals that NPs can induce alterations in the content and structure of lipids and proteins. DOM, N*P, pH, N*pH and pH*hardness have a statistically significant effect on NPs' toxicity to biomolecular. The toxicity levels of NPs across Saskatchewan watersheds are evaluated and we find that NPs could have the greatest inhibition on microalgae growth in Souris River. Our findings indicate that multiple environmental factors should be considered during the ecological risk assessment of emerging pollutants.

The impacts of global atmospheric circulations on the water supply in select watersheds in the Indonesian Maritime Continent using SPI.

Despite the diverse atmospheric circulations affecting the Indonesian Maritime Continent (IMC), i.e., El Nino Southern Oscillation-ENSO, Indian Ocean Dipole-IOD, Madden Julian Oscillation-MJO, Monsoon, there is a lack of research on their interaction with hydrological events in watersheds. This study fills this gap by providing insights into the dominant atmospheric events and their correlation with the water supply in three characteristic watersheds, i.e., Tondano (north/Pacific Ocean), Jangka (south/Indian Ocean), and Kapuas (equatorial/interior) in IMC. The research used the standardized precipitation index for the 1-monthly (SPI1), 3-monthly (SPI3), and 6-monthly (SPI3) scale generated from 23 years (2000-2022) of monthly historical satellite rainfall data. The analysis compared each location's SPI indices with the monthly Nino 3.4, Dipole Mode Index (DMI), MJO (100E and 120E), Monsoon index, and streamflow data. The result shows that the dominant atmospheric events for the Tondano watershed were ENSO, IOD, and MJO, with correlation values of -0.62, -0.26, and -0.35, respectively. The MJO event was dominant for the Kapuas watershed, with a correlation value of -0.28. ENSO and IOD were dominant for the Jangka watershed, with correlation values of -0.27 and -0.28, respectively. The monsoon correlated less with the SPI3 in all locations, while it modulates the wet and dry period pattern annually. Most intense dry periods in Tondano occur with the activation of El Nino, while the intense wet period occurs even in normal atmospheric conditions. Most intense wet periods in Jangka occur with the activation of La Nina, while the intense dry period occurs even in normal atmospheric conditions. The occurrence of MJO compensates for the intense wet and dry periods in Kapuas. The correlation among SPI3, atmospheric circulation, and streamflow in the diverse watershed characteristics in the IMC watersheds could give strategic information for watershed management and applies to other watersheds with similar atmospheric circulation characteristics.

Impact of land use land cover changes on ecosystem service values in the Dire and Legedadi watersheds, central highlands of Ethiopia: Implication for landscape management decision making.

Land use land cover change in a landscape is the main driver of degradation in ecosystem goods and services. This study was aimed at analysing the dynamics of the LULC change in the catchments of the water supply reservoirs as well as the impact on the Ecosystem Service Values (ESVs) between 1985 and 2022. The benefit transfer method was used to evaluate ecosystem service value (ESV) changes in response to LULC. The watersheds experienced substantial LULC changes. As a result, the natural vegetation, grasslands, and eucalyptus plantations declined dramatically, while settlements and cultivated lands considerably increased. The global and local ESV estimates show a dramatic decline in ESVs between 1985 and 2022. According to global and local ESV estimates, total ESV in the Legedadi watershed has decreased from approximately US$ 65.8 million in 1985 to approximately US$ 11.9 million in 2022 and from approximately US$ 42.7 million in 1985 to approximately US$ 9.66 million in 2022. According to global and local ESV estimates, total ESV in the Dire watershed decreased from approximately US$ 437 thousand in 1985 to approximately US$ 59 thousand in 2022 and from approximately US$ 225 thousand in 1985 to approximately US$ 36 thousand in 2022. The overall decline in ESV demonstrates that the natural environment is deteriorating as a result of replacement of the natural land cover by other economic land uses. Hence, it is highly recommended that implementing sustainable watershed management practices to halt the dramatic loss of natural ecosystems must be a high priority.

Core and conditionally rare taxa as indicators of agricultural drainage ditch and stream health and function.

BACKGROUND: The freshwater microbiome regulates aquatic ecological functionality, nutrient cycling, pathogenicity, and has the capacity to dissipate and regulate pollutants. Agricultural drainage ditches are ubiquitous in regions where field drainage is necessary for crop productivity, and as such, are first-line receptors of agricultural drainage and runoff. How bacterial communities in these systems respond to environmental and anthropogenic stressors are not well understood. In this study, we carried out a three year study in an agriculturally dominated river basin in eastern Ontario, Canada to explore the spatial and temporal dynamics of the core and conditionally rare taxa (CRT) of the instream bacterial communities using a 16S rRNA gene amplicon sequencing approach. Water samples were collected from nine stream and drainage ditch sites that represented the influence of a range of upstream land uses. RESULTS: The cross-site core and CRT accounted for 5.6% of the total number of amplicon sequence variants (ASVs), yet represented, on average, over 60% of the heterogeneity of the overall bacterial community; hence, well reflected the spatial and temporal microbial dynamics in the water courses. The contribution of core microbiome to the overall community heterogeneity represented the community stability across all sampling sites. CRT was primarily composed of functional taxa involved in nitrogen (N) cycling and was linked to nutrient loading, water levels, and flow, particularly in the smaller agricultural drainage ditches. Both the core and the CRT were sensitive responders to changes in hydrological conditions. CONCLUSIONS: We demonstrate that core and CRT can be considered as holistic tools to explore the temporal and spatial variations of the aquatic microbial community and can be used as sensitive indicators of the health and function of agriculturally dominated water courses. This approach also reduces computational complexity in relation to analyzing the entire microbial community for such purposes.

Streamflow duration curve to explain nutrient export in Midwestern USA watersheds: Implication for water quality achievements.

As part of federal programs to reduce nutrient pollution, states across the Midwest have developed nutrient reduction strategies, which focus on implementation of agricultural conservation practices (ACPs) or best management practices (BMPs). Despite several decades of federal investment in implementing ACPs/BMPs for reducing nutrient pollution, nutrient pollution is a continuing and growing challenge with profound implications for water quality and public health as well as ecological functions. Pollutant transport depends on water and sediment fluxes, which are governed by local hydrology. Therefore, knowing how flow conditions affect nutrients export is critical to develop effective nutrient reduction strategies. The objective of this study was to investigate the role of streamflow duration curve in controlling nutrient export in the western Lake Erie Basin and the Mississippi River Basin. To achieve this goal, we used long-term monitoring data collected by the National Center for Water Quality Research. We focused on the percentage of the annual pollutant load (nitrate-NO3-N, dissolved reactive phosphorus-DRP, total phosphorus-TP, and total suspended solids-TSS) exported during five flow intervals that spanned the flow duration curve: High Flows (0-10th percentile), Moist Conditions (10-40th percentile), Mid-Range Flows (40-60th percentile), Dry Conditions (60-90th percentile), and Low Flows (90-100th percentile). The results show that the top 10% of flows (i.e., high flows) transported more than 50% of the annual nutrient loads in most of the studying watersheds. Meanwhile, the top 40% of flows transported 54-98% of the annual NO3-N loads, 55-99% of the annual DRP loads, 79-99% of the annual TP loads, and 86-100% of the annual TSS loads across the studying watersheds. The percentage of the annual loads released during high flows increased as the percentage of the agricultural land use in the watershed increased, but it decreased as the watershed area increased across different watersheds. Finally, flow condition/nutrient export relationships were consistent over studying period. Therefore, reducing nutrient loads during high flow condition is the key for effective nutrient reduction.

Days-ahead water level forecasting using artificial neural networks for watersheds.

Watersheds of tropical countries having only dry and wet seasons exhibit contrasting water level behaviour compared to countries having four seasons. With the changing climate, the ability to forecast the water level in watersheds enables decision-makers to come up with sound resource management interventions. This study presents a strategy for days-ahead water level forecasting models using an Artificial Neural Network (ANN) for watersheds by conducting data preparation of water level data captured from a Water Level Monitoring Station (WLMS) and two Automatic Rain Gauge (ARG) sensors divided into the two major seasons in the Philippines being implemented into multiple ANN models with different combinations of training algorithms, activation functions, and a number of hidden neurons. The implemented ANN model for the rainy season which is RPROP-Leaky ReLU produced a MAPE and RMSE of 6.731 and 0.00918, respectively, while the implemented ANN model for the dry season which is SCG-Leaky ReLU produced a MAPE and RMSE of 7.871 and 0.01045, respectively. By conducting appropriate water level data correction, data transformation, and ANN model implementation, the results of error computation and assessment shows the promising performance of ANN in days-ahead water level forecasting of watersheds among tropical countries.

Methods and technologies for spatial analysis of regional ecosystems based on the watershed approach.

The watershed management approach is an efficient tool for organizing and implementing natural resource management at the regional and interregional levels. Statistical processing of watershed information contributes to a comprehensive assessment of the environment of the river watersheds at different hierarchical levels. The purpose of this work is to use spatial analysis and data simulation for assessing the state of ecosystems in hydrologically defined geographical areas such as watersheds. The minimal watersheds of the "pilot" territory of four watersheds in Eastern Siberia with an average area of approximately 1ha are used as elementary territorial units. For each watershed, spatial analysis tools form a set of attributes of unique natural characteristics, which are obtained using ground and satellite data. Such a set of attributes can be used to assess the state of the territory employing various methods of mathematical modeling and statistical and cluster analysis. Watershed modeling of the territory was carried out based on the MERIT Hydro digital elevation model. Based on Terra MODIS satellite information, data on temperature, vegetation indices, and vegetation cover were obtained for each watershed. The NASA Global Precipitation Measurement reanalysis data were used to generate the data on accumulated precipitation for all elementary watersheds. Analysis of the seasonal dynamics of the surface temperature in the study area was made, and statistical distributions of temperature variations during the year were obtained for each watershed. Effective temperature sum was calculated. Statistical values and average annual characteristics of trends in several vegetation indices were obtained for each watershed. The necessary methods and technologies for generating, storing, and processing data on each watershed have been developed. Integr Environ Assess Manag 2023;19:972-979. © 2021 SETAC.

Implementing community-engaged ecological research in Proctor Creek, an urban watershed in Atlanta, Georgia, USA.

The Southeast Region of the United States Fish and Wildlife Service (USFWS) implemented community-engaged research in Proctor Creek, an urban watershed in Northwest Atlanta, Georgia, to sample for aquatic species of concern in Atlanta, Georgia's Proctor Creek Watershed as a part of the Urban Waters Federal Partnership program. This research shifted the focus of the agency from the endangered and pristine natural spaces to a major city watershed negatively impacted by urbanization and other human influences for more than a century. Team members from USFWS, Proctor Creek Watershed residents, local students, and other stakeholders in the Urban Waters Federal Partnership (UWFP) spent three months conducting stream surveys and participating in community-led events to build relationships and learn community priorities. The team collected data at 11 sites throughout the Proctor Creek Watershed, visually assessed each site, and collected aquatic species using dip nets, seines, and traps. We observed approximately 28 aquatic species, including 13 unique fish species, and eight macroinvertebrate species, including two unique crayfish species. We also observed varying degrees of ecological health throughout the watershed. Native aquatic animal species were found at all stream sites, no matter the condition of the stream. Through creating training resources and disseminating data among team members for future sampling, the team established pathways to keep natural resource stewardship sustainable without direct federal involvement. Through engaging in community-engaged research to achieve the mission of the agency, the USFWS Proctor Creek Watershed survey helped shift the paradigm of how government agencies can connect their mission statements to the ever-changing complex needs of the American public.

Riparian buffers increase future baseflow and reduce peakflows in a developing watershed.

Land conversion and climate change are stressing freshwater resources. Riparian areas, streamside vegetation/forest land, are critical for regulating hydrologic processes and riparian buffers are used as adaptive management strategies for mitigating land conversion effects. However, our ability to anticipate the efficacy of current and alternative riparian buffers under changing conditions remains limited. To address this information gap, we simulated hydrologic responses for different levels of buffer protection under a future scenario of land/climate change through the year 2060. We used the Soil and Water Assessment Tool (SWAT) to project future streamflow in the Upper Neuse River watershed in North Carolina, USA. We tested the capacity of riparian buffers to mitigate the effects of future land use and climate change on daily mean streamflow under three buffer treatments: present buffer widths and fully forested 15 m and 30 m buffers throughout the basin. The treatments were tested using a combination of a future climate change scenario and landcover projections that indicated a doubling of low-intensity development between 2017 and 2060. In areas with >50 % development, the 30 m buffers were particularly effective at increasing average daily streamflow during the lowest flow events by 4 % and decreasing flow during highest flow events by 3 % compared to no buffer protection. In areas between 20 and 50 % development, both 15 m and 30 m buffers reduced low flow by 8 % with minimal effects on high flow. Results indicate that standardized buffers might be more effective at a local scale with further research needing to focus on strategic buffer placement at the watershed scale. These findings highlight a novel approach for integrating buffers into hydrologic modeling and potential for improved methodology. Understanding the effects of riparian buffers on streamflow is crucial given the pressing need to develop innovative strategies that promote the conservation of invaluable ecosystem services.