How to manage future groundwater resource of China under climate change and urbanization: An optimal stage investment design from modern portfolio theory

Identification of priority conservation areas based on ecosystem services and systematic conservation planning analysis

In order to reverse the trend of ecological deterioration and resolve the conflict between ecological conservation and economic development, it is necessary to evaluate the trends of ecosystem services (ESs) and unravel the relationship between ESs and environmental drivers and identify the priority areas for ESs. In this research, we used the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model to quantify the variation of four important ESs (water purification, water yield, soil conservation, and habitat quality) in the Dongting Lake Basin from 2000 to 2015. During the past 15 years, water yield was declined by 3.38% and soil conservation was increased by 1.45%. Water quality purification was deteriorated with the rise in phosphorus export (5.32%) and nitrogen export (4.09%). Meanwhile, habitat quality was decreased by 3.27%. Trade-offs occurred primarily among water yield and other ESs. Social-ecological drivers importance analysis found that water yield was primarily influenced by precipitation and temperature. By contrast, water purification and habitat quality were more affected by the distribution of land use and land cover (LULC). Soil conservation was closely related to precipitation and geographical factor. Based on the distribution of ESs and the intensity of human activities, we delineated priority areas for each ESs using the systematic conservation planning tool (Marxan). LULC shifted most dramatically in water yield reserves (6.49%) with a large amount of lands conversed to cropland (4.4%) and build-up land (0.27%), which further increased the risk of water scarcity, while LULC changed less in other ESs priority areas due to human activities. Our study helps develop conservation strategies within specific area cost-effectively and provides scientific support for future conservation program of ESs formulation and adjustment.

Subsurface groundwater aquifer mapping and quality characterization in Matiari district, Sindh, Pakistan

Groundwater, is an alternative resource, is used as a supplement for irrigation as well as drinking purposes in Pakistan. This paper aims to determine the quantum and quality of groundwater in Matiari district of Sindh, Pakistan, through Electrical Resistivity Survey (ERS). The ERS was conducted at 52 location points using the ABEM Terrameter SAS 4000. The quantity of good quality groundwater has also been evaluated with ArcGIS interpolation techniques, i.e., the maximum percentage of fresh groundwater is 34% the marginal fresh groundwater 43% at the depth of with few patches of saline groundwater aquifers. Moreover, at 50-m depth, the percentage of fresh groundwater reduces to 21% and the marginal has increased to 48%. However, groundwater below the depth from 50 to 100 m was found only 8% fresh groundwater, 29% marginal, 49% salt water, and 14% high salt water. Analysis of groundwater samples for quality showed a good agreement with the quality obtained from VES results. In addition, a socio-economic survey of 55 tube well owners were conducted through interviews related to groundwater suitability and usage. According to the survey, about 62% of respondents are using good quality groundwater; however, 36% consuming the marginal and the remaining 2% are utilizing the hazardous quality of groundwater. The consumer satisfaction survey showed most farmers (89%) were satisfied with the groundwater usage, while 11% were unsatisfied due to poor-quality groundwater. The crop productivity could be enhanced through awareness and conjunctive use of marginal quality groundwater with the canal water.

Groundwater sustainability: Developing a non-cooperative optimal management scenario in shared groundwater resources under water bankruptcy conditions

Groundwater level drawdown changes the hydrological cycle and poses challenges such as land subsidence and reduction of the groundwater quality. In this study, a new approach using a simulation-optimization framework was developed for shared groundwater management under water bankruptcy conditions (where water demand is greater than the allowable discharge capacity of water resources). The novelty of this study lies in using bankruptcy rules and a game model to manage a bankrupted shared groundwater resource considering aquifer sustainability. Accordingly, groundwater flow in the aquifer was numerically simulated by a finite-differences model (MODFLOW). Then, the repeated performance code of the finite-differences model was run for different discharge scenarios, and the results were applied to develop an MLP-ANN meta-model. By coupling the meta-model with a non-dominated sorting genetic algorithm II (NSGA-II)-based multi-objective optimization model, an optimized cultivation pattern under water bankruptcy conditions was achieved. Then, six different bankruptcy methods were utilized to specify groundwater allocation between three stakeholders. To manage the water bankruptcy conditions, different scenarios considering various groundwater extraction rates and cultivation areas were defined, and the optimization model was recoded for each scenario to find the corresponding optimized cultivation pattern. To consider the competition between stakeholders for groundwater extraction, a non-cooperative 3-player game was applied to achieve a compromise for different combinations of management strategies, which maximizes the profit and yields the best cultivation scenario. Applicability of the proposed methodology was investigated in an aquifer system located in Golestan Province, Iran, including three regions (Minudasht, Azadshahr, and Gonbade-kavus). Results show that the proposed method is capable of managing the bankruptcy conditions by generating greater agricultural profit and reducing groundwater drawdowns.

Groundwater quality for potable and irrigation uses and associated health risk in southern part of Gu'an County, North China Plain

The study area is a part of the North China Plain, where groundwater is heavily abstracted for drinking and irrigation purposes. Groundwater quality is adversely affected due to rapid economic development and urbanization. Therefore, the purposes of this study were to evaluate the suitability of groundwater for drinking and irrigation purposes and to quantify the associated human health risks in the southern part of Gu'an County, North China Plain. The matter-element extension method based on entropy weight was used to evaluate the water quality for drinking, while sodium adsorption ratio, sodium percentage (%Na), residual sodium carbonate and magnesium hazard were used to evaluate the water quality for irrigation. Non-carcinogenic and carcinogenic health risks via different exposure ways were evaluated for different age groups. The study found that the quality of both deep and shallow groundwater in this area was generally suitable for drinking. Deep water quality has better quality than the shallow water. However, 8.70% and 73.92% of water samples pose non-carcinogenic health risks on adults and children, respectively. Children and adults are also at cancer risk due to Cr⁶⁺ and As in drinking groundwater in this area. The main responsible parameters for non-carcinogenic risk are Cr⁶⁺, F^- and Fe, and Cr⁶⁺ is also responsible for carcinogenic risk. These toxic elements are mainly from industries. Therefore, deterioration of groundwater quality can be prevented by strengthening the sewage management of various industries.

Can groundwater be protected from the pressure of china's urban growth?

Groundwater is expected to be more vulnerable to water-quality degradation in the future due to rapid urbanization. However, despite knowledge that protecting future groundwater resources is necessary for sustainable groundwater resource development, little is known about the role of groundwater policy in influencing the spatial distribution of urbanization. This study sheds light on how a policy that protects vulnerable groundwater could affect the distribution of urban expansion. Groundwater vulnerability to pollution under future climate change scenarios is used as a factor to generate urban expansion probability maps for China. The results indicate that there will be a significant and uneven urban growth by 2030, if current trends in urban expansion continue. The amount of urban land in 2030 will range from 2.9 to 4.2 times the urban area in 2010. Meanwhile, the urban expansion probability maps for projections with and without consideration of groundwater vulnerability in urban suitability are compared. The comparation shows that consideration of a groundwater policy would significantly alter the future spatial distribution of urban areas. Even with a weight of only 10% for groundwater vulnerability in the urban suitability consideration, the percentage of change area in the urban expansion probability distribution map can be as high as 60%. The probabilities of urban expansion are forecast to gradually transfer from the southeast coastal areas to inland areas as higher weight (from 10% to 50%) of groundwater vulnerability is given to urban suitability consideration. Our study demonstrates that groundwater protection from urbanization pressures can be achieved, provides support for policy and decision makers in evaluating options to modify existing urban expansion policies, and concludes that groundwater protection at the macro-scale is an appropriate policy goal.

Optimization of management strategies for reducing nitrogen loading in China

Terrestrial Nitrogen (N) loading in the environment has seen a steady increase over the past several decades as a result of more intensive anthropogenic activities. Quantifying N loading for an extended period is important for effective N management. In this study, a statistical model is constructed to describe the relationship between N loading and anthropogenic activities at watershed scale for 211 watersheds covering the entire land area of China. Subsequently, a portfolio optimization model is used to optimize the future management efforts of the long-term N loading. Our results show that N loading in China due to anthropogenic activities has increased significantly over the past 60 years (1949-2010), with the rate of increase at approximately 1 Tg N/year. When designing future N loading management strategies, the next 30 years is divided into three temporal stages and assume that the total amount of expenditure is fixed. The results of portfolio optimization analysis show that the best allocations of management efforts (e.g. capital investments, making new policies, improving technology, or alike) among three temporal stages are 28.55% (2021-2030), 71.45% (2031-2040) and 0 (2041-2050). Furthermore, it is suggested that the future population growth scenario has the largest influence on the results of the portfolio optimization analysis.

Urban Green Spaces and Their Need in Cities of Rapidly Urbanizing India: A Review

Urbanization offers several opportunities for the growth of economic, social, and technology sectors, offering benefits to society in terms of better living and healthcare facilities, as well as employment opportunities. However, some major downsides of urbanization are overcrowding and environmental degradation. In order to realize sustainable and environmentally friendly urbanization, there is an urgent need for comprehensive land use planning and of urban settlements by giving due consideration to create and sustain urban green spaces (UGS) such as parks, gardens, roadside vegetation, etc. UGS play a vital role in reducing air pollution, mitigating climate change, and providing various ecosystem services. UGS are being deteriorated substantially due to booming urbanization in developing countries such as India. This review is focused on highlighting the many challenges in creating and maintaining UGS in the Indian context. It is a compilation of available reports on problems linked with poor land use and/or planning of urban settlements. The challenges associated with the management and maintenance of UGS are described. The poor and irregular watering of many existing UGS is one of the major issues among several others requiring immediate attention to resolve the problem of deteriorating UGS in some cities of India. As the groundwater resources are rapidly depleting because of ever increasing water demand, UGS are being dispensed with poor and irregular watering resulting in their deterioration. A list of possible solutions and prospects of UGS in cities aiming to become smart cities soon are discussed in this review. Efficient wastewater treatment and a non-potable reuse system are possible solutions for better prospects of UGS, and therefore, optimism of better cities with low to null urban heat island effect.

Hydrogeochemical Characterization and Suitability Assessment of Groundwater: A Case Study in Central Sindh, Pakistan

Groundwater is the most important water resource, on which depends human geo-economic development and survival. Recent environmental changes and anthropogenic activities render groundwater severely vulnerable. Groundwater in Central Sindh, Pakistan, is facing a similar situation. Hydrogeochemical characteristics of the groundwater in the said region were investigated by analyzing 59 groundwater samples via agricultural and drinking indices, using various statistical methods and graphical approaches to identify factors affecting groundwater. Major reactions occurring in the groundwater system were quantified by hydrogeochemical modeling. A statistical summary reveals the abundance of cations is Na⁺ > Ca²⁺ > Mg²⁺ > K⁺, while the abundance of anions is HCO₃⁻ > Cl⁻ > SO₄². Groundwater chemistry is mainly of rock dominance. Correlation analysis and graphical relationships between ions reveal that ion exchange and rock weathering such as the dissolution of halite, albite, and dissolution of carbonate minerals are important rock–water interactions, governing the evolution of groundwater chemistry. Hydrochemical facies are predominantly of mixed CaMgCl and Na-Cl type, with few samples of Ca-HCO₃ type, which constitutes fresh recharged water. Based on the Water Quality Index (WQI), 28.82% samples were found to be unsuitable for drinking. A United States Salinity Laboratory (USSL) diagram, Wilcox diagram, and other agricultural indices indicate that majority of the groundwater samples fall within the acceptable range for irrigation purposes.

Effects of human activities and climate change on the reduction of visibility in Beijing over the past 36 years

Both climate change and intensive human activities are thought to have contributed to the impairment of atmospheric visibility in Beijing. But the detailed processes involved and relative roles of human activities and climate change have not been quantified. Optical extinction of aerosols, the inverse of meteorological visibility is especially sensitive to fine particles <1.0 μm. These submicron particles are considered more hazardous than larger ones in terms of cardiovascular and respiratory diseases. Here we used the aerosol optical extinction (inverse of visibility) as the indicator of submicron particles pollution to estimate its inter-annual variability from 1980 to 2015. Our results indicated that optical extinction experienced two different periods: a weakly increasing stage (1980-2005) and a rapidly increasing stage (2005-2015). We attributed the variations of optical extinction to the joint effects of human activities and climate change. Over the past 36 years, human activities played a leading role in the increase of optical extinction, with a positive contribution of 0.077 km^-1/10 y. While under the effects of climate change, optical extinction firstly decreased by 0.035 km^-1/10 y until 2005 and then increased by 0.087 km^-1/10 y. Detailed analysis revealed that the abrupt change (around 2005) of optical extinction resulted from the trend reversals of climate change. We found since 2005 the decreasing trend by 0.58 m·s^-1/10 y in wind speed, the growing trend at 8.69%/10 y in relative humidity and the declining trend by 2.72 hPa/10 y in atmospheric pressure have caused the rapid increase of optical extinction. In brief, the higher load of fine particles <1.0 μm in Beijing in recent decades could be associated with both human activities and climate change. Particularly after 2005, the adverse climate change aggravated the situation of submicron particles pollution.

Integrating priority areas and ecological corridors into national network for conservation planning in China

Considering that urban expansion and increase of human activities represent important threats to biodiversity and ecological processes in short and long term, developing protected area (PA) network with high connectivity is considered as a valuable conservation strategy. However, conservation planning associated with the large-scale network in China involves important information loopholes about the land cover and landscape connectivity. In this paper, we made an integrative analysis for the identification of conservation priority areas and least-cost ecological corridors (ECs) in order to promote a more representative, connected and efficient ecological PA network for this country. First, we used Zonation, a spatial prioritization software, to achieve a hierarchical mask and selected the top priority conservation areas. Second, we identified optimal linkages between two patches as corridors based on least-cost path algorithm. Finally, we proposed a new framework of China's PA network composed of conservation priority and ECs in consideration of high connectivity between areas. We observed that priority areas identified here cover 12.9% of the region, distributed mainly in mountainous and plateau areas, and only reflect a spatial mismatch of 19% with the current China's nature reserves locations. From the perspective of conservation, our result provide the need to consider new PA categories, specially located in the south (e.g., the middle-lower Yangtze River area, Nanling and Min-Zhe-Gan Mountains) and north regions (e.g., Changbai Mountains), in order to construct an optimal and connected national network in China. This information allows us better opportunities to identify the relative high-quality patches and draft the best conservation plan for the China's biodiversity in the long-term run.

Ecological vulnerability assessment for ecological conservation and environmental management

Identifying ecological vulnerable regions is a significant aspect in ecological conservation and environmental management. This paper presents a first attempt to provide a prototype framework that can assess ecological vulnerability and evaluate potential impacts of natural, social, economic, environmental pollution, and human health elements on ecological vulnerability with integrating spatial analysis of Geographic Information System (GIS) method and multi-criteria decision analysis (MCDA). A general ecological vulnerability index was constructed to describe the vulnerability status in an ecological hotspot of China. The assessment results of this study confirm the poor ecological vulnerability in China that only 1.32% of the China's population lives in not vulnerable ecosystem. A very high percentage (98.68%) of Chinese with 1.34 billion people lives in vulnerable and highly vulnerable area. This situation is mainly caused by increasing population pressure, exhausted nature resources, extensive economic growth, severe environmental pollution, insufficient environmental protection investment, and accelerating population aging. The spatial comparison indicates that spatial disparity existed in China with the central and northwestern provinces showing higher ecological vulnerability than the northeastern and southern provinces. The results of ecological vulnerability assessment can support effective guidance for mid- or long-term ecologic management. The developed framework can be replicated at different spatial and temporal scales using context-specific datasets to support ecological managers and government with decision-making. With available robust climate change models, future research might incorporate climate change into the ecological vulnerability framework.

Coupling Modern Portfolio Theory and Marxan enhances the efficiency of Lesser White-fronted Goose's (Anser erythropus) habitat conservation

Climate change and human activities cause uncertain changes to species biodiversity by altering their habitat. The uncertainty of climate change requires planners to balance the benefit and cost of making conservation plan. Here optimal protection approach for Lesser White-fronted Goose (LWfG) by coupling Modern Portfolio Theory (MPT) and Marxan selection were proposed. MPT was used to provide suggested weights of investment for protected area (PA) and reduce the influence of climatic uncertainty, while Marxan was utilized to choose a series of specific locations for PA. We argued that through combining these two commonly used techniques with the conservation plan, including assets allocation and PA chosing, the efficiency of rare bird's protection would be enhanced. In MPT analyses, the uncertainty of conservation-outcome can be reduced while conservation effort was allocated in Hunan, Jiangxi and Yangtze River delta. In Marxan model, the optimal location for habitat restorations based on existing nature reserve was identified. Clear priorities for the location and allocation of assets could be provided based on this research, and it could help decision makers to build conservation strategy for LWfG.

Long-term variations in sediment heavy metals of a reservoir with changing trophic states: Implications for the impact of climate change

Two dated sediment cores from the Miyun Reservoir of Beijing in China were analyzed to reconstruct the pollution history of heavy metals including cadmium (Cd), chromium (Cr), iron (Fe), nickel (Ni), and zinc (Zn) as well as phosphorus (P). Enrichment factor (EF) and geoaccumulation index (I_geo) were applied to assess the enrichment status of heavy metals. Average EF and I_geo values indicated that the studied heavy metals in the sediments mainly originated from non-point source pollution and soil-water erosion, showing low ecological risks. In addition, correlation analysis and principal component analysis (PCA) identified that Cd, Zn, and P were mainly from agricultural diffusion pollution caused by utilization of the phosphate fertilizer; Zn, Ni, and Cr originated from soil erosion. PCA analysis was further conducted to investigate the relationships among meteorological factors, algae-dominant total organic carbon (TOC), and heavy metals. Results showed that algae-dominant TOC had strong positive correlation with temperature, which can be explained by that increased temperature accelerated the growth of algae. Meanwhile the opposite loadings between algae-dominant TOC and heavy metal suggested that primary production played an important role in migration and transformation of metals. Moreover, stepwise multiple regression models showed that Fe was sensitive to temperature, which accounted for approximately 39.0% and 40.1% of the variations in Fe of two sediment cores, respectively. Fe showed significant decreasing trends during the past 50years. Reductive environment of water-sediment interface caused by increasing temperature probably contributed to the restoration of ferric iron, resulting in the release of soluble Fe to overlying waters. Future climate change with elevated temperature and extreme weather events will aggravate the ecological risk of heavy metals in water environment due to the enhanced leaching effect and non-point source pollution as well as the release of heavy metals from sediments to water environment.

Atmospheric deposition of mercury and cadmium impacts on topsoil in a typical coal mine city, Lianyuan, China

Mercury (Hg) and cadmium (Cd) in the atmosphere from coal combustion emissions play an important role in soil pollution. Therefore, the purposes of this study were to quantitatively evaluate the atmospheric Hg and Cd deposition and to determine the influence of atmospheric deposition on Hg and Cd contents in surface soil in a typical coal mine city. Atmospheric deposition samples were collected from May 2015 to May 2016 at 17 sites located in industrial, agricultural and forest areas in the Lianyuan city. Atmospheric Hg and Cd deposition fluxes in the different land use types showed high variability. Curvilinear regression analysis suggested that the atmospheric Hg deposition fluxes were positively related with Hg contents in soils (R² = 0.86359, P < 0.001). In addition, atmospheric Cd deposition fluxes were also positively correlated with Cd contents in soils when the site LY02, LY04 and LY05 (all belong to agricultural land) were not included in the fitting (R² = 0.82458, P < 0.001). When they were included, there was no significant relationship between them (R² = 0.2039, P = 0.05). The accumulation of Hg and Cd concentration in topsoil due to the influence of atmospheric deposition will increase rapidly in the next 30 years, and the mean value of the increment will reach 2.6007 and 33.344 mg kg^-1. After 30 years, the Hg and Cd concentration will increase slowly. The present study advocates that much attention should be paid to the potential ecological hazards in soil resulting from the atmospheric Hg and Cd deposition.

Characterization and hydraulic behaviour of the complex karst of the Kaibab Plateau and Grand Canyon National Park, USA

The Kaibab Plateau and Grand Canyon National Park in the USA contain both shallow and deep karst systems, which interact in ways that are not well known, although recent studies have allowed better interpretations of this unique system. Detailed characterization of sinkholes and their distribution on the surface using geographical information system and LiDAR data can be used to relate the infiltration points to the overall hydrogeological system. Flow paths through the deep regional geological structure were delineated using non-toxic fluorescent dyes. The flow characteristics of the coupled aquifer system were evaluated using hydrograph recession curve analysis via discharge data from Roaring Springs, the sole source of the water supply for the Grand Canyon National Park. The interactions between these coupled surface and deep karst systems are complex and challenging to understand. Although the surface karst behaves in much the same way as karst in other similar regions, the deep karst has a base flow recession coefficient an order of magnitude lower than many other karst aquifers throughout the world. Dye trace analysis reveals rapid, conduit-dominated flow that demonstrates fracture connectivity along faults between the surface and deep karst. An understanding of this coupled karst system will better inform aquifer management and research in other complex karst systems.

Heavy metals and metalloid distribution in different organs and health risk assessment for edible tissues of fish captured from Honghu Lake

Honghu Lake is the seventh largest freshwater lake in China, and fishery is one of the most important economic sources for local inhabitants. Toxic metal concentrations in muscle of all analyzed fish species captured from Honghu Lake were generally below China standards, except Cr in crucian carp. The average concentrations were decreased in the following order, Zn (14.65 mg/kg) > Cr (1.25 mg/kg) > Cu (0.5994 mg/kg) > Pb (0.0884 mg/kg) > Cd (0.0069 mg/kg) > As (0.0007 mg/kg). There was no significant health risk in consuming fish captured from Honghu Lake, based on the analysis results of target hazard quotient (THQ), carcinogenic risk (CR), and estimated weekly intake (EWI). Mixed edible fish tissues consuming brought higher carcinogenic risks than muscle consuming. Pb was regarded as the major contributor of potential non-carcinogenic risk, while As of the potential carcinogenic risk. THQ set the most stringent allowed values of the average consuming amount of fish muscle at 1,316 g/d, while CR set the value of mixed fish tissues at 525 g/d.

Changes in heavy metal mobility and availability from contaminated wetland soil remediated with combined biochar-compost

The combination of biochar and compost has been proven to be effective in heavy metals contaminated wetland soil restoration. However, the influence of different proportions between biochar and compost on immobilization of heavy metals in soil has been less studied up to date. Therefore, we investigated the effect of different ratios of biochar-compost mixtures on availability and speciation distribution of heavy metals (Cd, Zn and Cu) in wetland soil. The results showed that applying all amendment combinations into wetland soil increased gradually the total organic carbon (TOC) and water-extract organic carbon (WEOC) as the compost percentage rose in biochar-composts. The higher pH was obtained in a certain biochar addition (20% and 40%) in combinations due to efficient interaction of biochar with compost. All amendments could significantly decrease availability of Cd and Zn mainly from pH change, but increase available Cu concentration as the result of increased water-extract organic carbon and high total Cu content in compost. Moreover, amendments can decrease easily exchangeable fraction and increase reducible of Cd and Zn greatly with increase of compost content in combinations, while amendments containing compost promote transformation of Cu from Fe/Mn oxide and residual fractions to organic bindings. These results demonstrate that different ratios of biochar and compost have a significant effect on availability and speciation of heavy metals in multi-metal-contaminated wetland soil.

Spatial distribution and source identification of heavy metals in surface soils in a typical coal mine city, Lianyuan, China

In this study, we investigated the pollution degree and spatial distribution of heavy metals and determined their sources in topsoil in a typical coal mine city, Lianyuan, Hunan Province, China. We collected 6078 soil surface samples in different land use types. And the concentrations of Zn, Cd, Cu, Hg, Pb, Sb, As, Mo, V, Mn, Fe and Cr were measured. The average contents of all heavy metals were lower than their corresponding Grade II values of Chinese Soil Quality Standard with the exception of Hg. However, average contents of twelve heavy metals, except for Mn, exceeded their background level in soils in Hunan Province. Based on one-way analysis of variance (ANOVA), the contents of Cu, Zn, Cd, Pb, Hg, Mo and V were related to the anthropogenic source and there were statistically significant differences in their concentrations among different land use patterns. The spatial variation of heavy metal was visualized by GIS. The PMF model was used to ascertain contamination sources of twelve heavy metals and apportion their source contributions in Lianyuan soils. The results showed that the source contributions of the natural source, atmospheric deposition, industrial activities and agricultural activities accounted for 33.6%, 26.05%, 23.44% and 16.91%, respectively.

Green residues from Bangkok green space for renewable energy recovery, phosphorus recycling and greenhouse gases emission reduction

Effective ways to integrate human life quality, environmental pollution mitigation and efficient waste management strategies are becoming a crisis challenge for sustainable urban development. The aims of this study are: (1) to evaluate and recommend an optimum Urban Green Space (UGS) area for the Bangkok Metropolitan Administration (BMA); and (2) to quantify potential renewable resources including electricity generation and potential nutrient recovery from generated ash. Green House Gases (GHGs) emissions from the management of Green Residues (GR) produced in a recommended UGS expansion are estimated and compared with those from the existing BMA waste management practice. Results obtained from this study indicate that an increase in UGS from its current 2.02% to 22.4% of the BMA urban area is recommended. This optimum value is primarily due to the area needed as living space for its population. At this scale, GR produced of about 334kt·y^-1 may be used to generate electricity at the rate of 206GWh·y^-1 by employing incineration technology. Additionally, instead of going to landfill, phosphorus (P) contained in the ash of 1077 t P·y^-1 could be recovered to produce P fertilizer to be recycled for agricultural cultivation. Income earned from selling these products is found to offset all of the operational cost of the proposed GR management methodology itself plus 7% of the cost of BMA's Municipal Solid Waste (MSW) operations. About 70% of the current GHGs emission may be reduced based on incineration simulation.

Risk management for optimal land use planning integrating ecosystem services values: A case study in Changsha, Middle China

Land-use change has direct impact on ecosystem services and alters ecosystem services values (ESVs). Ecosystem services analysis is beneficial for land management and decisions. However, the application of ESVs for decision-making in land use decisions is scarce. In this paper, a method, integrating ESVs to balance future ecosystem-service benefit and risk, is developed to optimize investment in land for ecological conservation in land use planning. Using ecological conservation in land use planning in Changsha as an example, ESVs is regarded as the expected ecosystem-service benefit. And uncertainty of land use change is regarded as risk. This method can optimize allocation of investment in land to improve ecological benefit. The result shows that investment should be partial to Liuyang City to get higher benefit. The investment should also be shifted from Liuyang City to other regions to reduce risk. In practice, lower limit and upper limit for weight distribution, which affects optimal outcome and selection of investment allocation, should be set in investment. This method can reveal the optimal spatial allocation of investment to maximize the expected ecosystem-service benefit at a given level of risk or minimize risk at a given level of expected ecosystem-service benefit. Our results of optimal analyses highlight tradeoffs between future ecosystem-service benefit and uncertainty of land use change in land use decisions.