Miyun Reservoir Watershed Research Articles

Comprehensive evaluation of nitrogen contamination in water ecosystems of the Miyun reservoir watershed, northern China: distribution, source apportionment and risk assessment.

Miyun Reservoir plays a vital role as a source of drinking water for Beijing, however it grapples with nitrogen contamination issues that have been poorly understood in terms of their distribution, source, and associated health risks. This study addresses this knowledge gap by employing data on nitrate nitrogen (NO3--N), chloride (Cl-), dual isotopic compositions of NO3- (δ15N-NO3- and δ18O-NO3-) data in water ecosystems, systematically exploring the distribution, source and health risk of nitrogen contaminants in Miyun reservoir watersheds. The results showed that over the past 30years, surface water runoff has exhibited a notable decrease and periodic fluctuations due to the combined influence of climate and anthropogenic activities, while the total nitrogen (TN) concentration in aquatic ecosystems presented an annual fluctuating upward trend. The TN concentration in the wet season was predominantly elevated because a large amount of nitrogen contaminants migrated into water ecosystems through heavy rainfall or river erosion. The concentration of NO3--N, the main contaminant of the water ecosystems, showed distinct variations across different watersheds, followed as rivers over the Miyun reservoir. Moreover, NO3--N levels gradually increased from upstream to downstream in different basins. NO3--N in surface water was mainly derived from the mixture of agricultural ammonia fertilizer and sewage and manure, with a minority of samples potentially undergoing denitrification. Comparatively, the main sources of NO3--N in groundwater were soil N and sewage and manure, while the denitrification process was inactive. The carcinogenic risks caused by NO3--N in groundwater were deemed either nonexistent or minimal, while the focus should predominantly be on potential non-carcinogenic risks, particularly for infants and children. Therefore, it is crucial to perform proactive measures aimed at safeguarding water ecosystems, guided by an understanding of the distribution, sources, and associated risks of nitrogen contamination.

Seasonal Variation and Driving Factors of Nitrate in Rivers of Miyun Reservoir Watershed, North China

In order to identify the seasonal variations and dominant driving factors of NO3-N in rivers, investigations of five consecutive years were conducted in seven rivers of the Miyun Reservoir Watershed. Significant seasonal variation of NO3-N in rivers was separately found in the dormant season (non-growing season) and the growing season. Furtherly, the V-shaped, W-shaped, and indistinct seasonal patterns of NO3-N accounted for 53.0%, 38.7%, and 8.3%, respectively. They were remarkably affected by stream flow, and their significant quadratic function was discovered. The annual maxima and minima of NO3-N corresponded to medium flow in the dormant season and low flow or flood in the growing season, respectively. On one hand, flood mainly played a role in the diluent for the Chao River with high NO3-N, and on the other hand, it acted as a nitrogen source for the Bai River with low NO3-N. The NO3-N was closely correlated with human activities, and this correlation had obvious seasonal change trend. In the dormant season, significant and mostly extremely significant high correlation coefficient (R) values were determined, while partly non-significant with low R values were found in July, August, September, and October. Increasing seasonal variation index of NO3-N from upstream to downstream was found that was gentle for large rivers and sharp for small tributaries. The seasonality of NO3-N was more affected by natural factors, especially flood, than human factors.

Material flow analysis of the nitrogen loading to surface water of Miyun reservoir watershed under uncertainty

Nitrogen (N) was one of the primary causes to water environment depravation, having a thorough understanding of N loading to water body is important for reducing the N pollution purposefully. In this research, we took the Miyun reservoir watershed as a typical area, of which a material flow model of the N metabolism was built. Afterwards, the material flow analysis (MFA) was conducted to identify the main pathways that generated N loading. And then the Monte Carlo (MC) method was applied to make uncertainty analysis of the N loading calculated through the MFA. The MFA results showed that the total N loading to surface water of the Miyun reservoir watershed was 5505.42 × 103 kg N, of which about 74.89% was originated from the agriculture subsystem (i.e., crop planting, fruit planting and vegetable planting subsystems). The main pathways of the agriculture subsystem that generated N loading were recognized as maize, chestnut, apple, pear, cabbage, cucumber and tomato planting. The uncertainty analysis results revealed that the N loading calculated from the MFA had some uncertainty, of which the fruit planting and industry subsystem had the biggest uncertainty, while the N loading from the fish farming subsystem had the lowest uncertainty. To make directed actions to protect the water quality of the Miyun reservoir watershed, the main pathways of each subsystem that generated N loading need to be regulated. This study provided a new framework of combing the MFA and MC method to simulate N loading to surface water at watershed scale, and was of vital significance to provide decision support for the watershed N pollution management globally.

Assessment of the Impacts of Land Use Change on Non-Point Source Loading under Future Climate Scenarios Using the SWAT Model

The Miyun Reservoir is an important source of surface drinking water in Beijing. Due to climate change and human activities, the inflow of Miyun Reservoir watershed (MRW) has been continuously reduced in the past 30 years, which has seriously affected the safety of Beijing’s water supply. Therefore, this study aimed to assess the mitigation measures based on the quantification of the integrated impacts of climate and land use change in MRW. The non-point source (NPS) model (soil and water assessment tool, SWAT) was used for the development of future climate scenarios which were derived from two regional climate models (RCMs) under two representative concentration pathways (RCPs). Three land use scenarios were generated by the land use model (conversion of land-use and its effects (CLUE-S)): (1) historical trend scenario, (2) ecological protection without consideration of spatial configuration scenario and (3) ecological protection scenario. Moreover, the reduction of sediment and nutrients under three future land use patterns in future climate scenarios was evaluated. The results showed that an appropriate land use change project led to the desired reduction effect on sediment and nutrients output under future climate scenarios. The average reduction rates of sediment, total nitrogen and total phosphorus were 11.4%, 6.3% and 7.4%, respectively. The ecological protection scenario considering spatial configuration showed the best reduction effect on sediment, total nitrogen and total phosphorus. Therefore, the addition of region-specific preference variables as part of land use change provides better pollutant control effects. Overall, this research provides technical support to protect the safety of Beijing’s drinking water and future management of non-point source pollution in MRW.

Concentration and Carbon Isotope Composition of DOC and DIC in the Miyun Reservoir Watershed in Summer

This study aims to complement existing research on the carbon cycle of water in reservoirs, for the effective control of nutrient input in drinking water. The content and isotopic compositions of water dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) from the Miyun Reservoir watershed in Beijing were studied, and water from the Jingmi diversion canal was also studied as a baseline reference. The results showed that the content of DOC in the Miyun Reservoir watershed in summer varied from 1.07 to 5.19 mg·L-1, with an average value of 2.61 mg·L-1. DOC in tributaries was lower than that of most rivers in China and globally, while DOC in reservoirs, particularly in Miyun Reservoir, was high. The high water level might be the main reason for the high DOC in the Miyun Reservoir. In summer, the δ13CDOC in the Miyun Reservoir watershed ranged from -27.4‰ to -24.3‰, with an average value of -25.8‰. Results from the isotopic analysis showed that the water in the Miyun Reservoir watershed was less affected by human sources, with the exception of some points. In summer, DOC in tributaries and in the Miyun Reservoir was mainly derived from soil organic matter and terrestrial C3 plants. In addition, endogenous substances also contributed to DOC in the watershed. DOC concentration increased along the Chao and Bai Rivers, and DOC from soil erosion and human sources was higher in the Chao River. The δ13CDIC in the study area varied from -12.6‰ to 5.75‰, with a mean value of -9.44‰. The weathering of carbonate rocks accounted for the major river DIC, and DIC had been clearly assimilated by the phytoplankton by photosynthesis. DOC and DIC in the Miyun Reservoir were significantly higher than in the Jingmi diversion canal (P<0.01), and the δ13CDIC in the Miyun Reservoir showed a clear positive deviation. This indicated that there were differences in carbon concentration and components in the two kinds of water, which might affect the denitrification capacity of the water in the Miyun Reservoir after mixing. In general, the dissolved carbon in the water of the Miyun Reservoir watershed is less affected by human sources. The conversion of DIC to DOC may also be a potential source of DOC in the study area.

A linear additivity water resources assessment indicator by combining water quantity and water quality

Water scarcity is a major problem faced by many parts of the world and seriously affects local development. Most of the previous water resources assessment only considered the water quantity and quality separately, and few studies had converted it into an indicator for assessment. We proposed a linear additivity indicator to calculate the amount of water resources by combining water quantity and water quality. The indicator named Water Quantity and Quality for Water Yield Equivalent (QQWYE). We calculated the water yield in the upstream watershed area of Miyun reservoir near Beijing, China in the year of 2000, 2008 and 2013. At the same time, we also used the QQWYE indicator to calculate the water yield equivalent on the basis of water yield, and made a sensitivity analysis of the results. Then the results of water yield and water yield equivalent were used to assess the amount of water resources. The results showed that the water yield in the study area in 2000, 2008 and 2013 were 372 × 106 m3, 723 × 106 m3 and 700 × 106 m3, respectively, and the water yield equivalent calculated using QQWYE were-206 × 106 m3, 553 × 106 m3 and 509 × 106 m3. This indicates that using the QQWYE indicator to assess water resources is more accurate than calculating water yield alone. In the sensitivity analysis, precipitation and evapotranspiration are highly sensitive to water yield and water yield equivalent, because climate change will significantly affect local precipitation and evapotranspiration. In the future watershed management, water consumption should be saved and water use efficiency should be improved to prevent climate change from having a significant impact on water resources. Beyond that, using a linear additivity indicator QQWYE to assess water resources can meet the principle of conservation of water resources. The calculation results of this study are relatively reliable and can provide a scientific basis for the sustainable management and rational utilization of water resources in the Miyun Reservoir watershed.

Agricultural nitrogen flow in a reservoir watershed and its implications for water pollution mitigation

Miyun Reservoir plays a fundamental role in providing drinking water for Beijing Municipality. In this study, agricultural nitrogen (N) flow was analysed for water pollution mitigation in Miyun Reservoir watershed. A partial substance flow analysis (SFA) method was applied to evaluate the historic changes in N flow from 2001 to 2017. Based on this method, N flow, N losses, N accumulation, and nitrogen use efficiency (NUE) over 17 years were identified and quantified. The results showed that N input, N output, and N stock gradually decreased in this period. The decline of N input mostly resulted from the considerable decrease in chemical fertilizer use and livestock excrement application. With decreasing N input, the N stock also decreased over these years. The N losses generally decreased, except for 2009–2012, as a result of the substantial increase in harvested grains which generated even more straw for feeding or burning. In addition, the average NUE was as low as approximately 15% which may due to the huge straw storage and N losses. It is indicated that there was a great potential to decrease N input especially chemical fertilizer for mitigation of water pollution through analysis. Therefore, combined technology innovation with policy impact was proposed in Miyun County. Reducing chemical fertilizer, improving waste cycling, reducing ammonia volatilization, preventing erosion and runoff and improving peasant awareness of environmental protection were proposed as recommendations. The historic analysis of N flow could be helpful to understand the challenges of N pollution. The integrated policy and technology measures will be effective to achieve water quality control. Both will provide a reference for other countries or regions with the similar issues.

Identification of Critical Source Areas of Nitrogen Load in the Miyun Reservoir Watershed under Different Hydrological Conditions

The spatiotemporal distribution of critical source areas (CSAs) will change with hydrological conditions. In this study, the CSAs of nitrogen load under different hydrological conditions in the Chaohe River watershed were identified using the cumulative pollution load curve method determined from the nitrogen pollution simulated using the Soil and Water Assessment Tool (SWAT) model. The results showed that: (1) The order of factors impacting nitrogen load intensity is as follows: fertilization intensity, rainfall, runoff, land use type, slope type, and soil type. (2) The primary and secondary CSAs are concentrated in the upper and lower areas of the watershed, where cultivated land (8.36%) and grassland (52.55%) are more abundant. The potential pollution source areas are concentrated in the upper and middle areas of the watershed, where cultivated land (6.99%), grassland (42.37%), and forest land (48.18%) are evenly distributed. The low-risk source areas are concentrated in the middle and left bank of the watershed, where forest land (67.65%) is dominant and the vegetation coverage is highest. The research results have significance for improving the accuracy of the implementation of best management practices, and can provide a reference for the formulation of drinking water protection policies for Beijing.

SWAT Model Simulation of Non-Point Source Pollution in the Miyun Reservoir Watershed

Non-point source pollution is becoming an important factor affecting water environment in China. The Soil and Water Assessment Tool (SWAT) model, the most powerful tool in measuring NPS, has played a significant role in NPS research across China. The suitability and calibration of the SWAT model is of primary importance. This study evaluated the effectiveness and applicability of SWAT model in runoff and nutrient load in Miyun Reservoir watershed. The SWAT model was also calibrated and validated using parameter sensitivity analysis, which showed that ALPHA_BF, SOL_AWC, CN2, NPERCO, PHOSKD and PPERCO were the most sensitive parameters, resulting in large variations in hydrological and nutrient loads. SWAT calibration and verification suggested it is a reliable method of measuring the NPS pollution in Miyun Reservoir watershed. This study estimated and analyzed spatial and temporal variations in NPS pollution loads in Miyun Reservoir watershed from 2005 and 2010. Significant variations in NPS pollution loads were found in different simulation periods. There were noticeable differences and an uneven distribution between high- and low-flow years. Nutrient loss occurred most frequently during high-flow years and wet seasons, the crucial period for pollution prevention. The results show that the total nitrogen loads is much higher than the total phosphorus loads. The pollution loads resulting from various land use types showed significant spatial differences: agricultural land had the most TN and TP load per unit area, followed by grassland. Forest land had the least pollution load per unit area. NPS load has a remarkable association with the spatial distribution of precipitation across the entire watershed.

Evaluating the performance of conservation practices under climate change scenarios in the Miyun Reservoir Watershed, China

Climate change is one of the major challenges in watershed management systems. Rising air temperatures, increasing precipitation in winter, and decreasing precipitation in summer as well as increases in extreme weather events have increased flooding and droughts and further affected water quality in the Miyun Reservoir Watershed (MRW). This study used the Soil and Water Assessment Tool (SWAT) model with five downscaled general circulation models (GCMs) to quantify the impact of climate change on hydrology, soil erosion, nutrient cycling, and the performance of Best Management Practices (BMPs) at watershed scale, driven by RCPs 2.6, 4.5, and 8.5. Compared with the baseline scenario, the results indicated that climate variability, especially precipitation and temperature, had great effects on surface runoff, sediment yields, and nutrient losses and further significantly affected BMP efficiency, although the magnitudes of change differed among the RCPs. Monthly sediment and nutrient loads increased substantially in all climate change scenarios, especially in flood season, due to the increase in precipitation intensity. Although BMPs were identified to be not appreciably effective in controlling water balance, they were effective in reducing sediment and nutrient losses. Based on this case, a simulation-optimization framework was applied to develop future watershed management strategies with BMP configurations because of their climate adaptation benefits, water improvement targets, and economical cost. The results indicated that the discrepancy among different climate scenarios was reflected by the number and types of BMPs and their spatial distributions, especially structural BMPs. This study suggests that the increasing frequency of rainfall events may decrease the efficiency of BMPs in the MRW, and watershed management should be adjusted according to changing climate in the future.

Quantifying effects of conservation practices on non-point source pollution in the Miyun Reservoir Watershed, China

Non-point source (NPS) pollution, including fertilizer and manure application, sediment erosion, and haphazard discharge of wastewater, has led to a wide range of water pollution problems in the Miyun Reservoir, the most important drinking water source in Beijing. In this study, the Soil and Water Assessment Tool (SWAT) model was used to evaluate NPS pollution loads and the effectiveness of best management practices (BMPs) in the two subwatersheds within the Miyun Reservoir Watershed (MRW). Spatial distributions of soil types and land uses, and changes in precipitation and fertilizer application, were analysed to elucidate the distribution of pollution in this watershed from 1990 to 2010. The results demonstrated that the nutrient losses were significantly affected by soil properties and higher in both agricultural land and barren land. The temporal distribution of pollutant loads was consistent with that of precipitation. Soil erosion and nutrient losses would increase risks of water eutrophication and ecosystem degradation in the Miyun Reservoir. The well-calibrated SWAT model was used to assess the effects of several Best Management Practices (BMPs), including filter strips, grassed waterways, constructed wetlands, detention basins, converting farmland to forest, soil nutrient management, conservation tillage, contour farming, and strip cropping. The removal rates of those BMPs ranged from 1.03 to 38.40% and from 1.36 to 39.34% for total nitrogen (TN) and total phosphorus (TP) loads, respectively. The efficiency of BMPs was dependent on design parameters and local factors and varied in different sub-basins. This study revealed that no single BMP could achieve the water quality improvement targets and highlighted the importance of optimal configuration of BMP combinations at sub-basin scale. The findings presented here provide valuable information for developing the sustainable watershed management strategies.

Impacts of climate change on watershed systems and potential adaptation through BMPs in a drinking water source area

Climate change, in terms of changes in temperature and patterns of precipitation, has significant impacts on water resources and watershed ecosystems. Adapting to climate change is becoming an important strategy for watershed management. The goal of this study was to quantify the impacts of climate change on watershed hydrological processes and water quality, to evaluate the efficiency of Best Management Practices (BMPs) and the possible effects of a changing climate, and to configure cost-effective BMPs at sub-basin scale using a multi-objective optimization method to mitigate climate effects on water resource. The Soil and Water Assessment Tool (SWAT) model was used to simulate the possible effects of changing climate on watershed hydrological and water-quality processes and adaptation options in the Miyun Reservoir Watershed (MRW). Climate change had significant impacts on water balance components such as precipitation, runoff, and evapotranspiration (ET) and on water-quality components such as sediment and nutrient loads. A substantial decreasing trend of runoff indicated that the Miyun Reservoir faced a more acute challenge of insufficient water-supply capacity. Compared with baseline climate, climate change represented by precipitation and temperature regimes resulted in substantial increases in sediment load (12.95%) and nutrient losses (7.26% for TN and 9.56% for TP) on average all sub-basins. Climate variability had significant effects on BMP efficiency through effects on watershed hydrology, soil erosion, and nutrient losses. Results highlight the importance of optimal configuration of site-specific BMPs at sub-basin scale for adaptation to climate change. The methods and findings presented here hold promise to enhance the resilience of the watershed system to current and future climate change.

Exploring effective best management practices in the Miyun reservoir watershed, China

Miyun reservoir watershed is a major source of drinking water for China’s capital, Beijing, which has a population of 21.75 million. Recently, the capacity of the Miyun reservoir to supply clean drinking water has been threatened by increasing eutrophication (or algae bloom), mainly due to the discharge of wastewater and excessive fertilization application in the upstream watershed. Therefore, there is an urgent need to design effective best management practices (BMPs) to reduce upstream nutrient load and improve water quality in the Miyun reservoir. In this study, we built a watershed model (the Soil and Water Assessment Tool) for the Miyun Reservoir Watershed (MRW) and calibrated and validated it using long-term sediment, nitrogen (N) and phosphorus (P) data. Furthermore, we developed a Markov Chain based multi-objective optimization program to explore optimal BMPs with tradeoffs between economic costs and water quality responses. Using the watershed model and multi-objective optimization algorithms, we explored the potential effectiveness of BMPs under two scenarios that are currently being considered. Scenario 1 assumes that funding for BMP implementation comes from national grants and targets high water quality standards, whereas scenario 2 assumes funding is provided by farmers and targets water quality that meet the drinking water standards. We found substantial discrepancies between the two scenarios with respect to the types and spatial configurations of BMPs and associated economic costs, highlighting the need to reconcile concerns from different stakeholders in order to arrive at a BMP plan that all parties will agree upon. In addition, we found that cross-subwatershed coordination and targeting flood season instead of year-round water quality standards could pronouncedly reduce the economic costs of BMP implementations without substantially degrading water quality. The watershed scale optimization method developed here holds promise to serve as an effective tool to explore tradeoffs between economic costs, water quality improvements, and decision makers’ and stakeholders’ concerns in BMP design, thereby informing sustainable watershed scale water resources management and ecosystem maintenance.

A simulation–optimization modeling approach for watershed-scale agricultural N2O emission mitigation under multi-level uncertainties

In this research, an integrated simulation–optimization modeling approach (ISOMA) was developed for supporting agricultural N2O emission mitigation at the watershed scale. This approach can successfully combine soil N2O emission simulation and the consequential mitigation management within a general modeling framework. Also, uncertainties associated with the key soil parameter can be effectively reflected and addressed through adoption of Monte Carlo analysis for the simulation results. The Monte Carlo simulated results were then used to generate fuzzy membership functions that can be consequentially used for emission mitigation management, reflecting the combined uncertainties for N2O emission simulation and mitigation management. The developed ISOMA was then applied to a reservoir watershed in Miyun county of Beijing municipality. In the studying watershed, the simulation model was calibrated and verified. Then, N2O emission from multiple agricultural land-use patterns were predicted. The amounts of N2O emission of four land use patterns (i.e., cash tree, orchard, cropland, and natural forest) were (536.9, 590.8, 653.1), (237.7, 254.4, 275.9), (79.5, 100.7, 105.1), (33.0, 47.3, 61.1) kg CO2 eq ha−1 year−1, respectively. Two scenarios (i.e., G1 and G2) were set up according to development priorities of local economy and society. Meanwhile, multiple credibility levels were considered according to the risk of N2O emission. The land use patterns could be adjusted according to solutions of ISOMA. The developed methods could help regional manager choose various production patterns with cost-effective agriculture N2O emission management schemes in the Miyun reservoir watershed. The manager also can obtain deeply insights into the tradeoffs between agricultural benefits and system reliabilities.

Impacts of climate change on stream flow and water quality in a drinking water source area, Northern China

Understanding the impacts of climate change on water quality and stream flow is important for management of water resources and environment. Miyun Reservoir is the only surface drinking water source in Beijing, which is currently experiencing a serious water shortage. Therefore, it is vital to identify the impacts of climate change on water quality and quantity of the Miyun Reservoir watershed. Based on long-time-series data of meteorological observation, future climate change scenarios for this study area were predicted using global climate models (GCMs), the statistical downscaling model (SDSM), and the National Climate Centre/Gothenburg University—Weather Generator (NWG). Future trends of nonpoint source pollution load were estimated and the response of nonpoint pollution to climate change was determined using the Soil and Water Assessment Tool (SWAT) model. Results showed that the simulation results of SWAT model were reasonable in this study area. The comparative analysis of precipitation and air temperature simulated using the SDSM and NWG separately showed that both tools have similar results, but the former had a larger variability of simulation results than the latter. With respect to simulation variance, the NWG has certain advantages in the numerical simulation of precipitation, but the SDSM is superior in simulating precipitation and air temperature changes. The changes in future precipitation and air temperature under different climate scenarios occur basically in the same way, that is, an overall increase is estimated. Particularly, future precipitation will increase significantly as predicted. Due to the influence of climate change, discharge, total nitrogen (TN) and total phosphorus (TP) loads from the study area will increase over the next 30 years by model evaluation. Compared to average value of 1961 ~ 1990, discharge will experience the highest increase (15%), whereas TN and TP loads will experience a smaller increase with a greater range of annual fluctuations of 2021 ~ 2050.

Classification of the Relationship between Household Welfare and Ecosystem Reliance in the Miyun Reservoir Watershed, China

Household welfare is inseparable from the environment because of its dependence on ecosystems and their services. However, linking household welfare and ecosystems in order to inform differentiated household livelihood development in spatially heterogeneous regions is still a great challenge. Based on a field survey of 1754 households, we grouped the relationships between household welfare (defined by total income) and ecosystem reliance (expressed by an index of dependence on ecosystem services) in the Watershed of Miyun Reservoir, the only source of surface water for domestic use in Beijing, China. The relationships can be grouped into four types: high welfare and high dependency; low welfare and low dependency; high welfare and low dependence; and low welfare and high dependency. Family structure, households’ education and skill level, and the proximity to Beijing have significant impacts on household welfare, while the quantity of natural capital and eco-compensation fund significantly contribute to the ecosystem dependence. Maintaining suitable family size and age structure, improving education and skill levels, and strengthening payment for ecosystem services within low welfare households would be effective approaches to their welfare improvement. The above classification can help design tailored policy and management options to promote sustainable livelihoods based on different household subgroups.

A comparison of single- and multi-site calibration and validation: a case study of SWAT in the Miyun Reservoir watershed, China

An essential task in evaluating global water resource and pollution problems is to obtain the optimum set of parameters in hydrological models through calibration and validation. For a large-scale watershed, single-site calibration and validation may ignore spatial heterogeneity and may not meet the needs of the entire watershed. The goal of this study is to apply a multi-site calibration and validation of the Soil andWater Assessment Tool (SWAT), using the observed flow data at three monitoring sites within the Baihe watershed of the Miyun Reservoir watershed, China. Our results indicate that the multi-site calibration parameter values are more reasonable than those obtained from single-site calibrations. These results are mainly due to significant differences in the topographic factors over the large-scale area, human activities and climate variability. The multi-site method involves the division of the large watershed into smaller watersheds, and applying the calibrated parameters of the multi-site calibration to the entire watershed. It was anticipated that this case study could provide experience of multi-site calibration in a large-scale basin, and provide a good foundation for the simulation of other pollutants in followup work in the Miyun Reservoir watershed and other similar large areas.

Field management of a drinking water reservoir basin based on the investigation of multiple agricultural nonpoint source pollution indicators in north China

Agricultural nonpoint source (NPS) pollution has become one of the major contributors to water quality degradation. It is of great significance to identify the spatial-temporal distribution and output characteristics of agricultural NPS pollution, and to explore the mitigation methods in typical watersheds, such as drinking water source area. In this study, taking the Miyun Reservoir watershed in China as the study area, the primary drinking water source in Beijing, the distribution patterns and output characteristics of agricultural NPS pollution were investigated and several field management methods were proposed, based on field experiments and a questionnaire survey. The results showed that different land use types had a significant influence on the distribution patterns of agricultural NPS pollutants, especially on the soil N content. Concurrently, soil NPS pollutant contents under different vegetation had significant temporal dynamics. The correlations between the NPS pollutant contents in the runoff and soil varied significantly with land use types. Significant correlations were observed for cropland and economic forest. Furthermore, there were significant differences for the agricultural activities and environmental consciousness of the local residents. Based on the results of the field experiments and the questionnaire survey, land use types, rainfall characteristics and agricultural activities were identified as the major factors affecting outputs of agricultural NPS pollution. Certain best management practices should be taken at the field scale to control the agricultural NPS pollution in the upstream of the Miyun Reservoir watershed.

Household Livelihood Strategy Choices, Impact Factors, and Environmental Consequences in Miyun Reservoir Watershed, China

Household livelihood strategies are embedded in the natural and socioeconomic contexts in which people live. Analyzing the factors that influence household livelihood choice and defining their consequences can be beneficial for informing rural household policies. In turn, this has great significance for fostering sustainable livelihood strategies. We grouped household livelihood strategies based on the income distribution of 756 households and analyzed their influencing factors and possible livelihood consequences in the watershed of Miyun Reservoir, the only source of surface water currently available for domestic use in Beijing, China. Local farmers’ livelihood strategies can be grouped into three types: farming, local off-farm, and labor-migrant. Farming households have the lowest livelihood capitals, other than natural capital, compared with labor-migrant households and off-farm households, the latter having better livelihood capital status. Geographical location, natural capital, household structure, labor quality, and ecological policies are the main factors affecting farmers’ choice of livelihood strategy. Local off-farm households have a significantly lower dependency on firewood, land resources, and investment than that of farming and labor-migrant households, and have the highest reliance on fossil fuel. This household classification can help us understand the livelihood characteristics, impact factors, and consequences of different types of household strategies, which also suggest tailored policy and management options to promote sustainable livelihoods based on different household types.

密云水库上游流域生态系统服务功能空间特征及其与居民福祉的关系

PDF HTML阅读 XML下载 导出引用 引用提醒 密云水库上游流域生态系统服务功能空间特征及其与居民福祉的关系 DOI: 10.5846/stxb201303120397 作者: 作者单位: 中国科学院生态环境研究中心 城市与区域生态国家重点实验室,中国科学院生态环境研究中心 城市与区域生态国家重点实验室,中国科学院生态环境研究中心 城市与区域生态国家重点实验室,中国科学院生态环境研究中心 城市与区域生态国家重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金资助项目（41371538）；城市与区域生态国家重点实验室科研专项资助项目（SKLURE2008-1-02）；国家基础研究重大专项资助项目（2009CB421105） Ecosystem services’ spatial characteristics and their relationships with residents’ well-being in Miyun Reservoir watershed Author: Affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences,,State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:生态系统管理的一个重要挑战是在区域尺度上管理生态系统服务并提高当地居民福祉。以2009年土地利用数据和社会经济数据为基础，利用InVEST模型和空间制图在乡镇尺度上对密云水库上游流域水资源供给服务、土壤保持服务、水质净化服务、产品供给服务以及居民福祉进行了定量评估和空间特征刻画，并探讨了生态系统服务与居民福祉的不同关系模式。结果表明，流域内各乡镇土壤保持服务从上游到下游呈逐渐递增的趋势，水质净化服务从上游到下游整体上也呈逐渐递增的趋势，流域内水质净化服务功能与水资源供给服务、粮食供给服务、蔬菜供给服务以及畜牧产品供给服务在空间上呈显著负相关；基于生态系统服务与居民福祉在空间上的聚集特征，可将56个乡镇划分为低服务低福祉模式、供给服务依赖模式和高服务高福祉模式，针对这3种关系模式特点，可分别提出改善生态系统服务功能和居民福祉的管理措施。案例研究可为其他区域实施分区管理、协调生态系统服务功能保护与居民福祉的关系提供借鉴。 Abstract:Understanding the characteristics of spatial coupling of ecosystem services and human well-being is the premise to strengthen ecological system management and then conserve ecosystem services and improve human well-being. The research community, however, mainly focused on the conceptual framework and the large-scale description since United Nations released Millennium Ecosystem Assessment in 2005. This study use the ecosystem services assessment model InVEST(Integrated Valuation of Ecosystem Services and Tradeoffs)to evaluate the special characteristics of water supply service, soil conservation service, water purification service, and provisioning ecosystem services. Specifically, we chose Miyun Reservoir watershed as a typical example, which is of vital importance to regulation of ecosystem services, to evaluate these characteristics such as such as food supply, the supply of livestock products, and the supply of vegetables at township scales in Miyun Reservoir watershed. Then we reveal the spatial characteristics of human wellbeing which utilize the per capita net income of farmers as proxy a indicator, and investigate different patterns of relationships between ecosystem service and human well-being. The results show that:(1) Ecosystem services appear to be a significant spatial heterogeneity in space in Miyun Reservoir watershed: water supply service turns out to first increase and then decrease from upstream to downstream; Both soil conservation service and water purification service show a consistent increasing tendency from upstream to downstream; and provisioning ecosystem services are higher at Chao and Bai river watershed and lower at the intermediate region.(2) The relationship between water purification service and water supply service, provisioning ecosystem services, and agricultural services turns out to be a significant negative correlation (P < 0.05). Agricultural development is a important factor to affect the ecosystem water purification services.(3) The residents' well-being shows a significant spatial heterogeneity in space: The rural per capita net income of farmers in Beijing is 4.46 times that in Heibei Province at province scale. And the residents' well-being doesn't show an apparent agglomeration at township scale.(4) Based on the special agglomeration characteristics of ecosystem services and residents' well-being at township scale, the 56 towns appear to contain three spatial coupling patterns: high well-being with high ecosystem services, human wellbeing depending on provisioning ecosystem services (a dependent pattern), and low well-being with low ecosystem services.(5) In order to achieve the win-win objective which can bring about both protect ecosystem services and improve residents' well-being, we propose management recommendations as follows: Emphasize to keep regulating services in high well-being with high ecosystem services pattern; Emphasize to keep provisioning ecosystem services in dependent pattern; Emphasize the implementation of ecological compensation policies in low well-being with low ecosystem services pattern. This study provides an insights to relationships between the spatial pattern of ecosystem services and residents' well-being, and reveals both the spatial coupled pattern and its characteristics. These findings provide scientific support for district and classification management, while the research methods and train of thought can provide a reference for protecting ecosystem services and simultaneously enhancing the well-being of residents for other basin management. 参考文献 相似文献 引证文献