Watershed Water Research Articles

Surface water – Groundwater Coupled Modelling for Watershed Water Resources Sustainability Assessment

There are limited studies in Cisangkuy Watershed which shows the water resources availability and variability with respect to changing climates and land use. Uncertainties due to climate change and population growth have created a critical water resources situation for Cisangkuy Watershed. These uncertainties come from undescribed quantification of surface water – groundwater interaction. Investigating spatio-temporal variability of recharge-discharge is a critical initial step for water-resource management. The main objective of this study is to set up a physically-based spatially distributed SWAT and MODFLOW for the analysis of the different hydrological and hydrogeological component. The objectives to be achieved include 1) identifying the characteristics and distribution of river stream recharge -discharge 2) assessing surface water and groundwater quantity. The result shows that calibrated SWAT-MODFLOW model can represent surface water – groundwater interaction in Cisangkuy Watershed spatio-temporally. Baseflow from aquifer discharge is main factor that give contribution to river discharge in study area, so we can conclude that Cisangkuy Watershed has a good potential of water resources on the low area, but also has high potential of disaster due to groundwater like flood and landslide.This study is expected to develop water resources management in Indonesia. So that water resources sustainability can be analyzed from the aspect of the quantity of surface water and groundwater.

Modeling Water Quality in Watersheds: From Here to the Next Generation.

In this synthesis, we assess present research and anticipate future development needs in modeling water quality in watersheds. We first discuss areas of potential improvement in the representation of freshwater systems pertaining to water quality, including representation of environmental interfaces, in-stream water quality and process interactions, soil health and land management, and (peri-)urban areas. In addition, we provide insights into the contemporary challenges in the practices of watershed water quality modeling, including quality control of monitoring data, model parameterization and calibration, uncertainty management, scale mismatches, and provisioning of modeling tools. Finally, we make three recommendations to provide a path forward for improving watershed water quality modeling science, infrastructure, and practices. These include building stronger collaborations between experimentalists and modelers, bridging gaps between modelers and stakeholders, and cultivating and applying procedural knowledge to better govern and support water quality modeling processes within organizations.

Quantitative assessment of surface hydrological connectivity in Momoge National Nature Reserve, Northeast China

Quantitative assessment of hydrological connectivity is a hot but difficult issue in current research. Using the 30-m resolution global monthly surface water remote sensing dataset released by the EU Joint Research Center and three indicators of geostatistical connectivity, maximum distance of connection (MDC), and surface water extent of connectome (i.e., seasonally connected water bodies), we quantified the hydrological connectivity of surface water in Momoge National Nature Reserve in different months of a normal year (May to October 2016), and in September of different hydrological years (a wet year, namely 1998; a normal year, namely 2016; a drought year, namely 2002), and different directions (west-east and north-south). Our results showed that: 1) the geostatistical connectivity function (GCF) along the west-east direction was better than that along the north-south direction. The GCF in August and July was better than that in other months. The GCF along the west-east direction of each hydrological year was better than that in the drought year, whereas the GCF in the drought year was better than the corresponding value in the normal year. The GCF along the north-south direction in each hydrological year was better than that in the normal year, whereas the GCF in the normal year was better than that in the drought year. The MDC along the west-east direction in June, July, September, and October of the normal year was all concentrated at 25.26 km. MDC was more concentrated along the north-south direction, with 10 km for all months. The MDC in the normal and drought years was relatively close, but both were much smaller than that in the wet year. 2) frequent seasonal connections between the Yuelianghu Reservoir and the Nenjiang River, and between Etoupao and its neighboring lakes occurred in the study area during the normal year, while most of the other lakes remained isolated. The patterns of hydrological connection in the study area differed across different hydrological years: two giant connectomes were formed in the wet year, some lakes are periodically connected in the normal year, and all lakes remain isolated in the drought year. 3) As a drainage area for farmland receding water, the surface water extent of the Etoupao connectome increased visibly during the three water supplement seasons (spring, summer, and autumn). By quantifying the surface hydrological connectivity in Momoge National Nature Reserve with multiple water sources from different perspectives, our results provide a scientific basis for wetland protection and restoration and integrated management of watershed water resources.

Groundwater from perennial springs provide refuge from wildfire impacts in mountainous semiarid watershed

Warming temperatures, earlier snowmelt, and the elongation of dry seasons are contributing to the propensity for more frequent and severe wildfires in semiarid, mountainous watersheds, which act as source watersheds for communities, especially in the southwestern United States. Research on how vegetation and water sources will respond following wildfires in these watersheds is critical for water resource, land, and forest managers. Little research has been completed on the effect of groundwater discharged from springs on revegetation of burned forests. We test whether springs, as perennial sources of water in semiarid watersheds, have the potential to protect roots and seeds from being damaged and facilitate the regrowth of native vegetation in areas affected by wildfires, thereby creating zones of fire refugia and mitigating the propensity for floods, erosion, and incursion of invasive species. The effect of springs on revegetation is studied in the Asaayi Creek Watershed located in the Chuska Mountains, NM/AZ, and in the Royal Gorge Park located near Cañon City, CO. In the Asaayi Creek watershed, remote sensing imagery and ground surveys show that springs facilitated revegetation following a June 2014 wildfire. Post-fire time lapse photography reveal more abundant vegetation around springs and more diverse vegetation in areas where there are multiple springs. Significantly higher Enhanced Vegetative Index (EVI) values are observed around perennial springs in the Asaayi Creek watershed and also around intermittent springs in the Royal Gorge area, one year after wildfires occurred in each study area. However, the revegetation around the perennial springs in the Asaayi Creek Watershed is widespread compared to Royal Gorge. There are multiple perennial springs that are clustered close together in Asaayi Creek Watershed, and only three intermittent flowing springs are located in the Royal Gorge burn area. Springs in the Asaayi Creek watershed provide a critical source of water that directly impacts soil moisture near the springs and in turn, protects roots and buds allowing native vegetation to regenerate.

Identifying watershed-scale spatiotemporal groundwater and surface water mixing function in the Yiluo River, Middle of China.

Researching the watershed-scale spatiotemporal groundwater and surface water mixing function, groundwater recharge heights and age can provide important information to watershed water sources management and water pollution controlling. In this study, 20 groundwater samples, 6 precipitation samples, and 40 surface water samples in the Yiluo River watershed in middle China were collected, and the mixing function between groundwater and surface water, recharge height, and age of groundwater was studied by using hydrochemistry (Cl, DO, EC, pH), radioactive isotopes (14C), and stable isotopes (13C, 18O, 15N). The results showed that river and shallow groundwater had frequent interaction. Evaporation function played a major role in the groundwater recharging process. Groundwater age displayed spatial and seasonal variations, and the age ranged from 660 to 2800years (dry season) and 560 to 1800years (wet season) in downstream and midstream, while the age range from 12,025 to 143,600years (dry season) and 10,560 to 12,650years (wet season) in upstream. The average recharge height of downstream and midstream both in dry and wet seasons is about 576.00 to 908.70m. While in upstream, both, in the dry and wet seasons, ranged from 1285 to 2680m. The mixing function between groundwater and surface water displayed spatiotemporal variety. These results of this study can provide useful information for the watershed-scale water resources management.

Hydrological process simulation in Manas River Basin using CMADS

Abstract The inability to conduct hydrological simulations in areas that lack historical meteorological data is an important factor limiting the development of watershed models, understanding of watershed water resources, and ultimate development of effective sustainability policies. This study focuses on the Manas River Basin (MRB), which is a high-altitude area with no meteorological stations and is located on the northern slope of the Tianshan Mountains, northern China. The hydrological processes were simulated using the China Meteorological Assimilation Driving Datasets for the SWAT model (CMADS) using the Soil and Water Assessment Tool (SWAT) model. Simulated runoff was corrected using calibration/uncertainty and sensitivity program for the SWAT. Through parameter sensitivity analysis, parameter calibration, and verification, the Nash–Sutcliffe efficiency (NSE), adjusted R-square ( R adj 2 {R}_{\text{adj}}^{2} ), and percentage bias ( PBIAS \text{PBIAS} ) were selected for evaluation. The results were compared with statistics obtained from Kenswat Hydrological Station, where the monthly runoff simulation efficiency was NSE = 0.64 \text{NSE}\hspace{.25em}=0.64 , R adj 2 = 0.69 {R}_{\text{adj}}^{2}\hspace{.25em}=0.69 , and PBIAS = – 0.9 \text{PBIAS}\hspace{.25em}=\mbox{--}0.9 , and the daily runoff simulation efficiency was NSE = 0.75 \text{NSE}\hspace{.25em}=0.75 , R adj 2 {R}_{\text{adj}}^{2} = 0.75, PBIAS \text{PBIAS} = −1.5. These results indicate that by employing CMADS data, hydrological processes within the MRB can be adequately simulated. This finding is significant, as CMADS provide continuous temporal, detailed, and high-spatial-resolution meteorological data that can be used to build a hydrological model with adequate accuracy in areas that lack historical meteorological data.

Evaluation of the Clinton River Watershed Water Quality as an Indication of Salinization due to Road Deicing Methods

The purpose of this study was to determine the full effect that road salting practices in Southeastern Michigan have had on local streams. The research method followed as an experimental procedure commonly used in the environmental science field. Variables measured include pH, total phosphates, nitrates, turbidity, salt content and conductivity. The resulting conclusions indicate a significant change in water quality between the non-winter and winter months tested. Although significant change was identified, no single value exceeded legal limits in the respective area.

Numerical rainfall-runoff model of Cimanuk Watershed before and after the operation of Jatigede Reservoir

Cimanuk watershed is one of the watersheds in West Java that has critical land. Critical land resulted in a Cimanuk watershed becomes a flood and drought. The management of Cimanuk Watershed water availability is done by regulating water supply from the Cimanuk River with the contruction of Jatigede Reservoir. The watershed hydrological process is the relationship between inputs in the form of rainfall, process, and output in the form of runoff. The process of converting rainfall into runoff is very complex, therefore, simplifying the rainfall-runoff model approach is needed. Hydrologic Engineering Center-hydrologic Modeling System (HEC-HMS) is one of the models for simulating rainfall into runoff. The purpose of the study is to simulate the availability of water surface at Cimanuk Hulu watershed using HEC-HMS hydrological modeling system based on before and after the operation of Jatigede reservoir. The results showed that the calibration of the model produced an NSE value of 0,640. On the other hand, the best validation results was in 2018 with NSE of 0,576 with the peak discharge value before the operation of the reservoir was of 456,8 m 3/s, and after modified with the presence of Jatigede Reservoir, peak discharge became 131,9 m 3/s.

Trade-off between watershed water yield and ecosystem productivity along elevation gradients on a complex terrain in southwestern China

Understanding the tradeoffs between water yield and ecosystem productivity is important for developing strategies for large scale ecological restoration worldwide. This study focused on a national forest protection project in the Upper Yangtze River Basin where a logging ban was implemented in 1998. We used a hydrologic model and remote sensing data to study the interactions between water and carbon cycles along elevation gradients in the Minjiang watershed (MJ), where extensive deforestation and reforestation have occurred in the past seven decades. Average annual evapotranspiration (ET), water yield, and gross primary productivity (GPP) from 2000 to 2015 were estimated as 429 mm yr−1, 555 mm yr−1, and 1002 g C m−2 yr−1, respectively. ET decreased sharply and consistently with increasing elevation, whereas GPP only decreased significantly in high elevation areas (i.e., >3,000 m), resulting in divergent trends of water use efficiency (WUE) with elevation. Evergreen needleleaf forests (ENF) contributed 28% of water yield and 37% of GPP at the watershed scale, while grassland (GRA) also contributed 28% of water yield, but only 20% of total watershed GPP. Moreover, runoff coefficients showed strong negative correlations with GPP, suggesting a general trade-off relationship between water yield and ecosystem productivity in MJ. Our results suggest that vegetation composition and elevation played a key role in determining the relative ecological benefits for carbon and water in the study watershed with a complex terrain.

Diagnóstico participativo de calidad de agua como herramienta para la gestión ambiental. El caso del Municipio de Vichadero, Rivera, Uruguay.

The current investigation comes from concerns expressed by local social actors in the municipality of Vichadero, Rivera, Uruguay and the lack of data on the conditions of the bodies of water in the area. The objective based on the perception of the community, was to identify the main environmental problems of the area, from a socio-environmental diagnosis using participatory methodologies, empowering through the collective production of knowledge from the people involved. This approach was put in dialogue with the results of physical-chemical and mutagenic analysis of the quality of surface water in the micro watershed of the area. This research provides evidence that similar processes could promote the involvement of local actors in monitoring and research processes associated with the environmental management of a locality.

Impacts of Urbanization on Watershed Water Balances Across the Conterminous United States

AbstractUrbanization impacts ecosystem functions and services by fundamentally altering the balances between precipitation, water yield (Q), and evapotranspiration (ET) in watersheds. Accurate quantification of future hydrologic impacts is essential for national urban planning and watershed management decision making. We hypothesize that “hydrologic impacts of urbanization are not created equal” as a result of the large spatial variability in climate and land use/land cover change (LULCC). A monthly water balance model was validated and applied to quantify the hydrologic responses of 81,900 12‐digit Hydrologic Unit Code (HUC) watersheds to historical and projected LULC in 2000, 2010, 2050, and 2100 in the conterminous United States (CONUS). Stepwise regression and Geographically Weighted Regression models were used to identify key factors controlling the spatially varied hydrologic impacts across CONUS. Although the simulated impact of future urbanization on mean change in water yield (ΔQ) was small at the national level, significant changes (ΔQ > 50 mm/year) were found in 1,046 and 3,747 watersheds by 2050 and 2100, respectively. Hydrologic responses varied spatially and were more pronounced in the eastern United States. Overall, the impacts of urbanization on water yield were influenced by local climate, previous LULC characteristics, and the magnitude of changes in land use and impervious surfaces. The continued increase in impervious surface, especially in previously urbanized watersheds, and background precipitation contributed most to future ΔQ through both increase in direct runoff and reduction in ET. Effective national‐scale integrated watershed management strategies must consider local climatic and LULC conditions to minimize negative hydrologic impacts of urbanization.

A comprehensive study on spectral analysis and anomaly detection of river water quality dynamics with high time resolution measurements

Systemic analysis of hydrology and water quality fluctuations using a data-intensive approach is an emerging research area and is significant for understanding hydrological processes. However, there is very limited understanding of the high-frequency characteristics of water quality fluctuations in the frequency domain. This study proposes a generic systemic framework to comprehensively analyse river water quality dynamics using a combination of Fourier and wavelet spectral analyses with high temporal resolution measurements. This framework identifies long-term, short-term, periodic, aperiodic, normal baseline and abnormal fluctuations, with particularly focus on detecting transient anomaly events due to their importance for watershed management. This study was conducted on the Potomac River, USA, where seven parameters, water temperature (Temp), pH, dissolved oxygen (DO), conductance (Cond), turbidity (Turb), nitrate plus nitrite (NOx-N) and discharge (Disc), were monitored every 15 min for two years at five sites/sub-catchments. Fast Fourier transform (FFT) revealed that Temp, pH and DO exhibited typical low-frequency periodic fluctuations, such as seasonal and bi-annual fluctuations, as well as interesting high-frequency periodic fluctuations, such as 12-hour and 8-hour fluctuations, which were identified as periodic anomalies. Cond, Turb and NOx-N presented universal temporal scaling phenomena, i.e., 1/f fluctuation, at all sites, as shown by the power spectral density. The scaling exponent β ranged between 1 and 3 and presented the order of βCond > βNOx-N > βTurb. The continuous wavelet transform (CWT) associated with contour-based scalograms successfully identified the time, location, duration and magnitude of transient anomaly events and classified two anomaly patterns: abrupt changes and large swings. The two patterns exhibited clearly different spectral energy distributions, i.e., pseudo-frequencies, on the CWT scales. A preliminary causality analysis found that the frequency of occurrence of turbidity anomaly events (FOATurb) was proportional to the product of the developed land area percentage and FOATemp, and FOANOx-N was proportional to the product of forest land area percentage and FOAdisc. Wavelet coherence analysis showed different hysteresis characteristics of different water quality parameters. In particular, Turb and NOx-N presented significantly different coherent fluctuation behaviours between high-frequency and low-frequency regions. Some findings of this study are still difficult to explain at this stage. High-frequency monitoring combined with spectral analysis provides new insights into the details of water quality dynamics, which can help to develop a new index and framework for the reliability, resilience, and management of watershed water quality vulnerability. These results can also be used to design new algorithms for online anomaly detection.

Identifying Nitrate Sources in a Typical Karst Underground River Basin

Underground rivers are an important source of groundwater in karst area. Recently, nitrate pollution of underground rivers has become a serious issue. To identify the sources of nitrate in Guancun typical karst underground river basin, stable isotope techniques (δ15N-NO3-, δ18O-NO3-, and δ18O-H2O) were applied in this study. The contribution rates of different nitrate sources in groundwater were quantitatively identified based on the stable isotope analysis in R (SIAR) model, and the influence of land use type on nitrate distribution and source in watershed water was clarified. The results showed that ① nitrate mainly came from fertilizers, soil organic nitrogen, and manure/sewage based to the isotopic composition of nitrate nitrogen and oxygen isotopes. It was revealed that non-point sources significantly contributed to nitrate in waters of the Guancun underground river basin. ② Nitrification dominated the formation process of nitrate in groundwater, and the initial values of nitrogen and oxygen isotopes were not affected by fractionation. ③ Based on SIAR, the contribution of different sources to nitrate in water in the basin varied seasonally, and the contributions of fertilizer, soil organic nitrogen, and manure/sewage to nitrate were 57.07%, 34.06%, and 8.87% in the wet season and 34.14%, 33.02%, and 32.84% in the dry season, respectively. Overall, the present study quantitatively evaluated the temporal variations of nitrate sources in a typical karst groundwater river basin and provided a theoretical foundation for prevention and control management of non-point source pollution and watershed management in karst areas.

Modelling the Vegetation Response to Climate Changes in the Yarlung Zangbo River Basin Using Random Forest

Vegetation coverage variation may influence watershed water balance and water resource availability. Yarlung Zangbo River, the longest river on the Tibetan Plateau, has high spatial heterogeneity in vegetation coverage and is the main freshwater resource of local residents and downstream countries. In this study, we proposed a model based on random forest (RF) to predict the Normalized Difference Vegetation Index (NDVI) of the Yarlung Zangbo River Basin and explore its relationship with climatic factors. High-resolution datasets of NDVI and monthly meteorological observation data from 2000 to 2015 were used to calibrate and validate the proposed model. The proposed model was then compared with artificial neural network and support vector machine models, and principal component analysis and partial correlation analysis were also used for predictor selection of artificial neural network and support vector machine models for comparative study. The results show that RF had the highest model efficiency among the compared models. The Nash–Sutcliffe coefficients of the proposed model in the calibration period and verification period were all higher than 0.8 for the five subzones; this indicated that the proposed model can successfully simulate the relationship between the NDVI and climatic factors. By using built-in variable importance evaluation, RF chose appropriate predictor combinations without principle component analysis or partial correlation analysis. Our research is valuable because it can be integrated into water resource management and elucidates ecological processes in Yarlung Zangbo River Basin.

Relationship Between Source-Sink Landscape Pattern and Antibiotics in Surface Water in Peri-urban Watershed

Quantitively identifying the effect of land use patterns on antibiotics in surface water has significance in maintaining water quality and protecting residents' health in urban and rural regions. In this study, a typical peri-urban watershed, located in the Yangtze River Delta, was selected as the study area. Based on surface water sampling, laboratory analysis, and source-sink landscape model (SSLM) analysis, the component and distribution characteristics of antibiotics in surface water in different sub-watersheds were analyzed. The effects of source and sink landscape patterns on antibiotic concentrations in surface water were identified. The results of this study showed substantial differences in types and concentrations of antibiotics in surface water in different sub-watersheds. The total concentrations of antibiotics in surface water ranged from 1.12 ng·L-1 to 53.74 ng·L-1. From upstream to downstream, the area of "source" landscape increased, and the area of "sink" landscape decreased based on landscape pattern analysis. The results of non-metric multidimensional scaling (NMDS) showed that sub-watersheds with similar "source-sink" landscape patterns were detected as having similar antibiotics types and concentrations in surface water. Land use composition, distance, elevation, and slope degree had substantial impacts on antibiotic concentrations in surface water. The results of this study also found that location-weighted landscape index (LWLI) was positive correlated with antibiotics concentrations in surface water based on correlation analysis and redundancy analysis. The sub-watersheds with high LWLI values usually had relatively higher antibiotic concentrations in surface water. This study indicated that optimization of "source" and "sink" landscapes at the watershed scale can decrease antibiotic contamination in surface water. Furthermore, SSLM is an effective tool in landscape optimization at the watershed scale.

Research on Organic Removal of Food Processing Waste-Water Based on Watershed Water Protection

If the waste water from the production of candied fruit, as one of the non-staple foods, is not treated up to the standard and discharged directly into the surface watershed. It will inevitably cause the pollution of the watershed water and affect the safety of production and domestic water. The biodegradable index of candie waste-water is higher than 0.45 due to the large amount of sugar, which is easily biodegradable. Because of the high value of BOD5, anaerobic fermentation method was adopted. The digestible sludge from the sewage treatment plant was taken and put into the plastic bucket with a ratio of 2:28 sludge waste water. The pollution index value of waste water was significantly reduced when the reaction was 60 h. The COD in the waste-water decreased by 1480.6 mg/L, and the COD removal rate reached 49.6%. The BOD5 of waste-water decreased by 793.6 mg/L, and the BOD5 removal rate reached 50.1%. The turbidity of waste-water decreased from 110.8NTU to 69.3 NTU, the turbidity decreased by 41.5 NTU, and the turbidity removal rate of waste-water reached 37.5%.

Characterizing the impacts of land use on nitrate load and water yield in an agricultural watershed in Atlantic Canada

Excessive nitrate loading from agricultural non-point source is threatening the health of receiving water bodies at the global scale. Quantifying the drivers/sources of water and nitrate flux in watersheds and relating them to spatial and temporal land uses is essential for developing effective mitigation strategies. This study investigated the impact of land use on water yield and nitrate loading to surface water in a typical agricultural watershed in Prince Edward Island (PEI), Canada. We used historical streamflow and water quality records to calibrate the comprehensive hydrological model Soil and Water Assessment Tool (SWAT), which was setup with detailed annual land use records. The SWAT model performed well in predicting both daily streamflow and nitrate load. Land use demonstrated little impact on water yield but affected nitrate load significantly. Annual nitrate load ranged from 5.6 to 44.4 kg N ha−1 yr−1 for forest and soybean, respectively. Potato rotated land contributed 84.5% of annual nitrate load to the watershed. Source of water yield demonstrated high variability between the growing season and non-growing season. About 90% of water yield was contributed by groundwater during growing season, while runoff contributed over 60% of water yield during the non-growing season. Groundwater was the dominant source of nitrate loading for both seasons. The watershed estuary faced the highest threats from subbasins in the south western area due to the high nitrate load and proximity to the watershed outlet. Results by the machine learning algorithm random Forest analysis indicated that the climatic variables of temperature and precipitation were the top two factors affecting water yield, with a combined relative importance of 61%. Land use was the dominant factor affecting nitrate load, the relative importance of land use alone was ~50%. The results of this study provided critical insights for watershed management in Atlantic Canada.

Dredged Material Quality in Anthropogenically Exploited Catchment Area

The paper is focused on the research of pollutants in dredged material and water in the watershed of the Sigord reservoir (Eastern Slovakia), which is influenced by anthropogenic activity. The monitored area extends to the cadastral area of ​​Zlatá Baňa, which has been used for a long time and intensively for mining of gold, antimony and mercury. After the end of mining activities (at the beginning of the 20th century) the territory remained devastated by numerous remains of mining activities and no attention has been paid to this area in terms of scientific research. Therefore, the monitoring of dredged sediment and water quality has been carried out. The results show that the limit values ​​of selected heavy metals (such as Sb, As, Hg, Pb, Cu, Zn, Ni, Fe and Al) are exceeded in both sediments and water in the reservoir watershed, as a result of the former mining activities around Sigord.

Bacterial communities and nitrogen transformation genes in streambank legacy sediments and implications for biogeochemical processing

Streambank legacy sediments may be important sources of sediment and nutrients from Mid-Atlantic watersheds. However, little is known about the nutrient processing roles of microorganisms that inhabit legacy sediments, let alone their composition, diversity, and distributions. In this study, we sampled 15 streambanks at multiple depths throughout four watersheds in the Mid-Atlantic Region of the USA. High throughput sequencing of 16S ribosomal RNA genes indicated that streambank microbial community composition varied within site depth and across contemporary land uses. Collectively, the most abundant microbial taxa in legacy sediments included Acidobacteria (25–45%), Proteobacteria (15–40%), Nitrospirae (2–10%), Chloroflexi (1–5%), and Actinobacteria (1–10%). Bacterial community composition was distinct between agriculture and urban sites as well as suburban and urban sites. There was significant variation in community composition between the top (1–25%), upper-middle (26–50%), and bottom layers (76–100%) of sediments, while the relative abundances differed between layers for only Acidobacteria and Proteobacteria. Several streambank chemistry variables (metals, %TC, and %TN) had weak positive correlations with community composition. Compared to ammonia-oxidizing bacteria, nitrifying archaea were more predominant. This study provides the first insights into detailed microbial composition of legacy sediments and identifies environmental drivers for community structure and nitrogen processing. Future studies should consider exploring the role of this unique microbial environment for nutrient processing and leaching from legacy sediments and its implications for watershed water quality.

Effects of payments for watershed services policy on economic growth: a case study based on the synthetic control method

Payments for watershed services (PWS) can provide financial incentives to the watershed water environment protection in upstream regions. It is necessary to understand the influence of watershed ecological protection on economic development. In this paper, taking the Xin’anjiang River basin as a case, synthetic control method was used to analyze the effects of PWS policy implemented in Huangshan City from 2012 on its per capita GDP. The results showed that the PWS policy had a negative effect on per capita GDP in Huangshan City, which was reduced by 1.73%. It indicated that the payments were not enough to offset the opportunity cost of upstream regions, proving that the conservation of the environment was at the expense of sacrificing economic growth. However, the ecosystems and society benefited from the PWS policy. Attention should be paid to balance the economy, ecology, and society in the process of development. In addition, compensation fund and market-based mechanisms could be applied to help alleviate the pressure of government finance to realize the social economy sustainable development.