Search

Global warming is exacerbating water security risks in watershed ecosystems. Hence, it is especially crucial to examine how blue and green water respond to drought in watershed ecosystems. This study utilized the Soil and Water Assessment Tool (SWAT) to investigate temporal and spatial variations in blue and green water resources within the Wujiang River Basin (WRB) across three distinct ecosystems: agriculture, forest, and grassland. Concurrently, the Standardized Precipitation Evapotranspiration Index (SPEI) was employed to assess drought risk in the basin, and the relationship between typical ecosystem blue and green water resources and drought response was further explored. The study's results revealed the following key findings: (1) From 1985 to 2014, the basin recorded an average total of 54129.8 × 106 m3 and 46227.7 × 106 m3 of blue and green water, respectively. Notably, forest ecosystems contributed 50 % and 62 % to the blue and green water resources, respectively. (2) In typical ecosystems, temporal changes in both blue and green water exhibited a pattern of initial increase followed by a decrease. Furthermore, spatial changes along the upstream-to-downstream gradient showed an initial decrease, followed by an increase, and ultimately another decrease. (3) In typical ecosystems, blue water is more affected by dry and wet conditions, while green water is influenced by a combination of dry and wet conditions and land use changes. (4) As drought intensity rises, both blue and green water resources in typical ecosystems decrease. Notably, green water in forest ecosystems is less affected by drought intensity, which contributes to maintaining water resource security in watershed ecosystems. These study findings provide a robust scientific foundation for water resource management and drought mitigation strategies in the basin.

Blue and green water resources are essential for human livelihood and the sustainable development of ecosystems. It is crucial to thoroughly examine the effects of climate change and land use change on these resources. This study takes the Wujiang River Basin as an example, which, as a typical mountainous basin, has more prominent water resource problems. Firstly, two sets of land use data from 1990, 2000 and 2010 were selected, considering various climate and land use change scenarios. The impact of climate and land use changes on blue and green water resources in the Wujiang River Basin from 1985 to 2014 was then quantitatively analyzed using the soil and water assessment tool (SWAT). Subsequently, the future land-use simulation (FLUS) model was employed to simulate land use in 2040, based on two periods of land use data (2000 and 2020). Finally, the SWAT model, driven by future land use data and two scenarios from the CMIP6 model (SSP2-4.5 and SSP5-8.5), projected the blue and green water resources in the Wujiang River Basin for the period 2015-2100. The results indicate the following: 1) The SWAT model demonstrated good performance in simulating the water cycle process in the Wujiang River Basin, with nash-sutcliffe coefficient (NSE) and coefficient of determination (R² ) values of 0.94 and 0.94 for the calibration period, and 0.77 and 0.87 for the validation period, respectively. 2) The FLUS model effectively simulated land use in 2020, achieving a Kappa coefficient of 0.764 and demonstrating its applicability for future land use simulations. 3) From 1985 to 2014, land use changes revealed reversibility patterns, with agricultural land being converted mainly into forest land and grassland, forest land being converted mainly into agricultural land and grassland, and grassland being converted mainly into agricultural land and forest land. 4) The period from 1985 to 2014 witnessed an initial increase followed by a decrease in blue and green water resources in the Wujiang River Basin, with blue water increasing by 137.3 mm/a and then decreasing by 127.5 mm/a, and green water increasing by 7.9 mm/a and then decreasing by 12.7 mm/a. Climate change accounts for 99% of blue water change and 85% to 90% of green water change, highlighting its predominant role in these shifts. 5) Urban land is projected to expand almost 1.5 times in 2040 compared to 2010. Both scenarios indicate an upward trend in blue and green water resources when contrasted with the historical base period (1985-2014), with the SSP5-8.5 forward period displaying the most substantial increase. This trend amplifies the risk of flooding and drought occurrences. These findings offer valuable insights for informed land use planning, integrated water resources management, and decision-making concerning future water resource management in the Wujiang River Basin. [ABSTRACT FROM AUTHOR]

Analysis of the relationships among ecosystem services (ESs) can help ensure that benefits from ecosystems are consistent over time. This study explored the spatial and temporal patterns of water supply (WS), grain supply (GS), carbon storage (CS), water conservation (WC), soil conservation (SC), and habitat quality (HQ) in the Wujiang River Basin (WJRB) from 2000 to 2020 and the trade-off/synergy relationships of ESs. The ESs in the WJRB are downstream > midstream > upstream in space, with the greatest increase and decrease in the upstream and midstream temporal dimensions, respectively. The WS, WC, and SC underwent a trend shift in 2005 due to climatic influences, whereas GS and HQ underwent a trend shift in 2010 due to human social development. GS formed a trade-off with other ESs in the spatial pattern, whereas WS formed a trade-off with CS and WC in the temporal dimension. Adjusting the GS spatial pattern reduces the trade-off between ESs in the spatial pattern, allowing for focusing on monitoring soil and water erosion-prone areas to prevent extensive soil erosion during heavy precipitation years; this reduces the trade-off between ESs in the time dimension in the WJRB. This provides a theoretical basis for achieving high-quality WJRB development. [ABSTRACT FROM AUTHOR]

Blue-green water evaluation can provide scientific suggestion for the comprehensive management of water resources in the basin. Here Wujiang river basin was as an example, based on the SWAT (Soil and Water Assessment Tool) hydrological model, the annual runoff anomaly percentage method was used to determine different precipitation patterns. The Mann-Kendall trend method(M-K) and the linear regression trend analysis method were applied to evaluate the temporal and spatial characteristics of blue-green water resources from 1992 to 2019 and the differences in the distribution and spatial distribution of blue-green water in different precipitation years. The results showed that: (1) the simulation of the SWAT model was better, which describe the water cycle process in Wujiang river basin. (2) The annual average precipitation, blue water resources and green water resources in the basin were 1126mm, 549mm and 589mm, respectively. The precipitation and blue water resources generally showed a decrease trend, but the green water resources exhibited an increase trend. (3) The green water coefficient were 46%, 52% and 58% in the wet year, normal year and dry year, respectively. Thus, the amount of green water resources has changed and plays an important role in ecosystem maintenance. (4) From the upstream to the downstream of the basin, the precipitation and blue water resources increased first and then decreased, while the green water resources presented a trend of first increasing, then decreasing and finally increasing. (5) The temporal and spatial variation of blue water resources was mainly impacted by the change of precipitation, while that of green water resources was affected by the change of precipitation, temperature, and land use cover. [ABSTRACT FROM AUTHOR]

Study region: Wujiang River Basin, China. Study focus: Blue and green water play key roles in water management and sustainable development in the Wujiang River Basin. It is essential to conduct a comprehensive study on the availability of blue and green water resources due to the uneven distribution of water resources in the basin. In this study, the monthly, seasonal, and interannual variations in blue and green water resources were analyzed during 1985–2014, and the changes in blue and green water resources were predicted for the period 2015–2100 based on the 5 Coupled Model Intercomparison Project Phase 6 (CMIP6). New hydrological insights for the region: From 1985–2014, blue water resources were dominant in the Wujiang River basin, accounting for 53.6% of the total water resources. Blue water resources exhibited an increasing trend, while green water resources exhibited a decreasing trend. Precipitation exhibited a much more significant impact on blue water resources than on green water resources. The spatial distribution of blue and green water resources in the basin is uneven, where the blue water resource with an annual average of 629.5 mm, indicating an increase followed by a decreasing trend from upstream to downstream. The green water resources had an annual average of 544.7 mm, with a decrease followed by an increasing trend from upstream to downstream. Delta and multi-model ensemble (MME) can effectively reduce the uncertainties associated with CMIP6 model output. Annual precipitation and mean annual temperature increase from 2015 to 2100 in SSP1–2.6, SSP2–4.5, SSP3–7.0, and SSP5–8.5. Compared to the baseline period, blue water resources show the highest growth in the recent (2015–2040) and intermediate (2041–2070) periods in SSP1–2.6, i.e., by 4.9% and 13.7%, respectively. In the final period (2071–2100), blue water resources exhibit the highest growth in SSP5–8.5, i.e., by 21.5%. The future projections indicated that the uneven spatial distribution of blue water resources in the basin will persist. This study improves our understanding of the blue and green water resources in the Wujiang River Basin under climate change scenarios and can provide valuable insights for integrated water resources management in the Wujiang River Basin.

Cultural route is the heritage expression of ethnic exchange, communication and integration, and it is an important resource for building the awareness of the Chinese nation community. With the theory of cultural route, this paper identifies the heritage of the shipping system of the Wujiang rive through literature collation and field investigation. The research finds that, shipping system of Wujiang river is composed of rich types of heritage and has the basic characteristics of cultural routes. It is a cultural route worthy of the name, which can be called Wujiang waterway. By discussing the characteristics and values of Wujiang waterway, this study can provide a heritage perspective of cultural routes for the research of inter-extensive promotion of ethnic exchange, communication and integration. [ABSTRACT FROM AUTHOR]

In the planning and restoration of land ecological space, the ecological restoration priority area has attracted more and more attention, especially in the regions with great vulnerability. As a typical area of karst ecological region in Southwest China, Wujiang River Basin experienced human disturbance and land uses which had great impacts on the ecological environment. Based on the land use evolution from 1985 to 2019, the change of ecological-production-living land in Wujiang River Basin was analyzed by transfer matrix, intensity analysis and long-time series trajectory approaches. The results showed that from 1985 to 2019, the ecological land in Wujiang River Basin significantly decreased, the production land increased first then decreased, and living land increased significantly. The reduced ecological land was mainly transformed to cropland. After 1990, the change intensity of land use in Wujiang River Basin gradually increased. At the category level, the intensity of forest land change was the most stable, and while that of barren land, shrub land and grassland were active. At the transition level, the increased impervious land was mainly from cropland, and the reduced forest land was mainly transformed into cropland. Trajectory analysis from 1985 to 2019 showed that the stable land use type of Wujiang River accounted for 67.36% of the total area of the basin and forest land was the main stable land use type. Our research spatially identified the land use change from different aspects which could be a new approach for ecological restoration. Also, our study can provide decision-making basis for the sustainable use of land resources in the study area.

Analysis of the relationships among ecosystem services (ESs) can help ensure that benefits from ecosystems are consistent over time. This study explored the spatial and temporal patterns of water supply (WS), grain supply (GS), carbon storage (CS), water conservation (WC), soil conservation (SC), and habitat quality (HQ) in the Wujiang River Basin (WJRB) from 2000 to 2020 and the trade-off/synergy relationships of ESs. The ESs in the WJRB are downstream > midstream > upstream in space, with the greatest increase and decrease in the upstream and midstream temporal dimensions, respectively. The WS, WC, and SC underwent a trend shift in 2005 due to climatic influences, whereas GS and HQ underwent a trend shift in 2010 due to human social development. GS formed a trade-off with other ESs in the spatial pattern, whereas WS formed a trade-off with CS and WC in the temporal dimension. Adjusting the GS spatial pattern reduces the trade-off between ESs in the spatial pattern, allowing for focusing on monitoring soil and water erosion-prone areas to prevent extensive soil erosion during heavy precipitation years; this reduces the trade-off between ESs in the time dimension in the WJRB. This provides a theoretical basis for achieving high-quality WJRB development.

The influence of cascade dams on the migration of microplastics (MPs) was conducted by analyzing the spatial distribution of MPs in sediments of the Wujiang river basin (Wujiang river basin) in Southwest China. The results showed that the abundance of MPs in Wujiang river basin sediments ranged from 310 to 2620 items/kg dw (mean: 1354 items/kg dw, a high level compared with aquatic sediments worldwide). The main chemical components of these MPs were polypropylene and polyethylene. High abundance of MPs in tributary sediments suggested that tributary inputs contributed to the main stream and reservoirs. Statistical analysis showed that gross domestic product (GDP) and the basin area of cascade reservoirs, rather than hydraulic retention time and reservoir age, were the dominating factors in the distribution of MPs in the Wujiang river basin. The accumulation of MPs in cascade reservoirs implied the interception effect of cascade dams. The rapid development of cascade dam systems and the interception effect of dams should be taken into account when predicting the flux of MPs from rivers to the ocean. Heavy metals found on the surface of the MPs showed the compound pollution of MPs and heavy metals in dammed rivers and cascade reservoirs. Our results deepen the understanding of the migration of MPs in rivers alongside intensive cascade hydropower development.

This paper innovatively combines the artificial bee colony (ABC) algorithm and the backpropagation neural network (BPNN) into a precipitation prediction model. The research data were collected by 17 stations in the Wujiang River Basin from 1961 to 2018, and compiled into a time series of precipitation data. Through wavelet analysis on precipitation series, the authors identified the features of precipitation distributions in time and frequency domains at different timescales, and demonstrated the inter-annual trend and abnormalities of precipitation in the basin. Next, the weights and thresholds of the BPNN was optimized by the ABC algorithm, and used to predict the precipitation of the basin in the next two decades. The predicted results were consistent with the periodicity and break points obtained by the wavelet analysis. The Z index was introduced to identify the flood years and drought years in the prediction period. The research results shed new light on climate prediction, flood control and drought resistance.

Traditional Chinese rural drama in the Wujiang River Basin has a long history, with a wide variety of dramas and various artistic forms. Nuo opera is one of the most representative types of traditional Chinese rural drama in the area. Since the 1980s, the study of Nuo opera culture in the Wujiang River Basin has mainly involved four aspects: the interpretation of Nuo opera and the origin of Nuo culture, the textual review of Nuo opera and the construction of Chinese Nuo opera history, the study on the aesthetic form of Nuo opera art and the research of intangible heritage protection and cultural inheritance, development and utilization of Tourism resources. These achievements have expanded the unique perspective of the study of Nuo culture in the Wujiang River Basin, and added new discourse space and academic growth points to the study of outstanding traditional Chinese rural drama culture. [ABSTRACT FROM AUTHOR]

Based on the daily precipitation observation data at 41 meteorological stations in the Wujiang River basin from 1960 to 2016, temporal and spatial distribution characteristics of the annual mean surface rainfall, the annual mean maximum daily precipitation, and the number and precipitation amount of the annual mean extreme precipitation in the Wujiang River basin during the study period were analyzed. The analysis shows the following results. (1) The annual rainfall and the number of raining days in the Wujiang River basin showed a significant increasing trend (both passed the 0.05 reliability test), while the intensity of the rainstorm showed no significant increase. The rainfall and the number of days of rainstorms from May to October were basically the constant. From mid-May to early August, there was a unimodal distribution; the intensity of rainstorm first increased and then decreased. (2) In the past 57 years, the annual mean maximum daily precipitation in the Wujiang River basin did not show significant linear variation, but the interdecadal changes were more obvious. (3) The mean annual number of extreme persistent heavy rainfall in the Wujiang River basin showed an insignificant decrease, but the extreme persistent heavy precipitation showed an insignificant increase. The maximum daily precipitation at five representative stations in Wujiang River basin was calculated using the Gumbel extreme value Ⅰ distribution method. It was found that there was a critical point of 50 a in the time scale of the return period.

Copyright of Journal of Shanghai University / Shanghai Daxue Xuebao is the property of Journal of Shanghai University (Natural Sciences) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper innovatively combines the artificial bee colony (ABC) algorithm and the backpropagation neural network (BPNN) into a precipitation prediction model. The research data were collected by 17 stations in the Wujiang River Basin from 1961 to 2018, and compiled into a time series of precipitation data. Through wavelet analysis on precipitation series, the authors identified the features of precipitation distributions in time and frequency domains at different timescales, and demonstrated the inter-annual trend and abnormalities of precipitation in the basin. Next, the weights and thresholds of the BPNN was optimized by the ABC algorithm, and used to predict the precipitation of the basin in the next two decades. The predicted results were consistent with the periodicity and break points obtained by the wavelet analysis. The Z index was introduced to identify the flood years and drought years in the prediction period. The research results shed new light on climate prediction, flood control and drought resistance. [ABSTRACT FROM AUTHOR]

• The spatial and temporal dynamics of blue and green water in typical ecosystems in the basin were evaluated. • Agriculture, forest and grassland ecosystems are the main ecosystems in the Wujiang River Basin. • Forest ecosystems account for 50% and 62% of total blue and green water, respectively. • The response of blue and green water to SPEI was analyzed. • Drought has various degrees of impact on blue and green water. Global warming is exacerbating water security risks in watershed ecosystems. Hence, it is especially crucial to examine how blue and green water respond to drought in watershed ecosystems. This study utilized the Soil and Water Assessment Tool (SWAT) to investigate temporal and spatial variations in blue and green water resources within the Wujiang River Basin (WRB) across three distinct ecosystems: agriculture, forest, and grassland. Concurrently, the Standardized Precipitation Evapotranspiration Index (SPEI) was employed to assess drought risk in the basin, and the relationship between typical ecosystem blue and green water resources and drought response was further explored. The study's results revealed the following key findings: (1) From 1985 to 2014, the basin recorded an average total of 54129.8 × 106 m3 and 46227.7 × 106 m3 of blue and green water, respectively. Notably, forest ecosystems contributed 50 % and 62 % to the blue and green water resources, respectively. (2) In typical ecosystems, temporal changes in both blue and green water exhibited a pattern of initial increase followed by a decrease. Furthermore, spatial changes along the upstream-to-downstream gradient showed an initial decrease, followed by an increase, and ultimately another decrease. (3) In typical ecosystems, blue water is more affected by dry and wet conditions, while green water is influenced by a combination of dry and wet conditions and land use changes. (4) As drought intensity rises, both blue and green water resources in typical ecosystems decrease. Notably, green water in forest ecosystems is less affected by drought intensity, which contributes to maintaining water resource security in watershed ecosystems. These study findings provide a robust scientific foundation for water resource management and drought mitigation strategies in the basin. [ABSTRACT FROM AUTHOR]

Focusing on the quantitative identification of the impacts of climate change and human activities on annual and maximum daily runoff at a basin scale, taking the Wujiang River Basin, South China for instance, this paper simulated and quantitatively evaluated the impacts of climate change and human activities on runoff and their contribution ratios to runoff at daily and annual scales by using the HIMS model and elastic coefficient method. The results showed that, the HIMS model performed well in the Wujiang River Basin at daily scale. The Nash-Sutcliffe coefficients are 0.85 and 0.77, and the absolute values of water balance errors are 3.1% and 3.3% respectively in calibration and validation periods. The results obtained by the HIMS model and the elastic coefficient method indicated that climate change is the dominat factor that leads to the increase of annual runoff and human activities cause the runoff decrease while its contribution ratio is smaller compared to that of climate change. The annual maximum daily runoff showed an upward trend due to climate change and human activities. The contribution ratios of climate change and human activities are 94% and 6% , respectively. Climate change has greater impact on annual maximum daily runoff than that on annual average runoff. [ABSTRACT FROM AUTHOR]

Thirty-four sampling sites for surface water and twenty-seven sampling sites for ground water in areas of different land use were selected in the Wujiang River Basin, upstream section in Guizhou Province, China. Carbonic anhydrase (CA) activity in surface and ground water was analyzed and compared. The results show that CA activity was detected in all surface and ground water samples. In general, average CA activity in surface and ground water was highest from samples in arbor lands, followed by shrub lands, shrub and grass lands, agricultural lands, and residential areas. The average CA activity in ground water from arbor lands, shrub lands, and shrub and grass lands was higher than that in surface water. Water CA activity was positively correlated with HCO3- concentration in surface water and ground water. These results imply that the contribution of CA in water to the karst carbon sink potential of river basins warrants further extensive and in-depth research. [ABSTRACT FROM AUTHOR]

The influence of cascade dams on the migration of microplastics (MPs) was conducted by analyzing the spatial distribution of MPs in sediments of the Wujiang river basin (Wujiang river basin) in Southwest China. The results showed that the abundance of MPs in Wujiang river basin sediments ranged from 310 to 2620 items/kg dw (mean: 1354 items/kg dw, a high level compared with aquatic sediments worldwide). The main chemical components of these MPs were polypropylene and polyethylene. High abundance of MPs in tributary sediments suggested that tributary inputs contributed to the main stream and reservoirs. Statistical analysis showed that gross domestic product (GDP) and the basin area of cascade reservoirs, rather than hydraulic retention time and reservoir age, were the dominating factors in the distribution of MPs in the Wujiang river basin. The accumulation of MPs in cascade reservoirs implied the interception effect of cascade dams. The rapid development of cascade dam systems and the interception effect of dams should be taken into account when predicting the flux of MPs from rivers to the ocean. Heavy metals found on the surface of the MPs showed the compound pollution of MPs and heavy metals in dammed rivers and cascade reservoirs. Our results deepen the understanding of the migration of MPs in rivers alongside intensive cascade hydropower development. [Display omitted] • Distribution and abundance of microplastics was investigated at a large watershed scale. • Tributary input is an important source of microplastics in the main stream and cascade reservoirs. • GDP and basin area, instead of HRT, dominated the distribution of microplastics. • Combined pollution of microplastics and heavy metals in dammed rivers needs to be concerned. [ABSTRACT FROM AUTHOR]

To promote ecosystem protection in the Wujiang River, this paper proposes a practical approach for calculating the environmental flow. The proposed approach combines the idea of the "guarantee rate" of the flow duration curve (FDC) method and the grading idea of the Tennant method. A daily flow series of the Wujiang River was compiled from 1956 to 2019 and used to compare the effect of the proposed approach versus the traditional approaches in four selected sections along the river. The results show that the environmental flow of the Wujiang River can be divided into five levels by the T-FDC method, with a level-by-level disparity, and all levels can capture the temporal and spatial variability of river flow. Additionally, the calculated basic environmental flow process ranges between the historical minimum and second minimum monthly average flow, and the threshold width of the optimal flow is more reasonable than the Tennant method. The T-FDC method can provide technical support for Wujiang River ecosystem management and sustainable development.

Guizhou is one of the most seriously contaminated regions with mercury in China, but mercury deposition fluxes in this region have not been well studied. Concentrations and wet deposition fluxes of total mercury (THg) and methyl mercury (MeHg) were measured from January to December 2006 at 5 sites in Wujiang River Basin, Guizhou, China. Monthly-integrated samples were collected using bulk precipitation samplers. Samples were treated rigorously according to our trace metal protocol, and THg was analyzed by cold vapor atomic fluorescence spectrometry (CVAFS) and MeHg by aqueous phase ethylation, GC separation, and CVAFS detection. The annual volume-weighted mean concentration and wet deposition fluxes of THg and MeHg for 5 sites were 36.0ngL−1 and 34.7μgm−2 yr−1, and 0.19ngL−1 and 0.18μgm−2 yr−1 in 2006, respectively. The proportion of MeHg to THg ranged from 0.2% to 2.3%, with the mean value of 0.7%. The results also showed that each site had a similar seasonal trend for mercury concentration and wet deposition flux. The largest wet deposition fluxes of THg and MeHg occurred during the rainy season (May–October) when the rainfall was greater, whereas the highest concentrations of THg and MeHg appeared during winter months (December–February). The monthly concentrations of THg and MeHg negatively correlated well with the monthly precipitation depth (r 2 =0.17 and 0.12), suggesting that scavenging of particle-bound mercury from the atmospheric is an important mechanism contribution to mercury in rain. [Copyright &y& Elsevier]

Changes in climate and the underlying surface are the main factors affecting runoff. Quantitative assessment of runoff characteristics, and determination of the climate and underlying surface contribution to changes in runoff are critical to water resources management and protection. Based on the runoff data from the Wulong Hydrological Station, combined with the Mann-Kendall test, Indicators of Hydrologic Alteration (IHA), Budyko hypothesis, and changes in climate and the underlying surface, this study comprehensively analyzed the runoff in the Wujiang River Basin (WRB). The results showed that: (1) The annual runoff of Wujiang River showed a downward trend, and an abrupt change occurred in 2005. (2) The overall hydrological change in WRB is 46%, reaching a moderate change. (3) The contribution rates of precipitation (P), potential evaporation ( ET 0 ), and underlying surface to runoff changes are 61.5%, 11.4%, and 26.9%, respectively. (4) After 2005, the WRB has become more arid, human activities have become more active, vegetation coverage has increased, and the built-up land has increased significantly.