Methods and accounts for water withdrawal at the city level and evaluation of sectoral water saving in China

In the context of the freshwater crisis, two-thirds of the cities in China suffer from freshwater scarcity, and there are restrictions on the use of water by industries. Although ‘Redline Regulation’ policies as core regulations were set to save water through improving water-withdrawal efficiency, China still has transnationally low efficiency owing to poor sectoral water-saving initiatives. Control on efficiency still lacks targeting and prioritization to specific sectors and cities. To save water at the city level has become a priority strategy of regulation and requirement in water field for China, yet how to conduct and realize it among various cities or sectors has not been fixed. Although high water-consumption activities are proposed in a few cities, comparison across the whole cities and economic-sectors could not be realized. Accounting for sectoral water withdrawal at the city level could help planners regulate water use in different sectors to improve water use efficiency. Thus, high-resolution water accounting methods and datasets in terms of spatiality and economic-sector are critical for China’s water saving. What is more, it is meaningful to investigate sectoral water-saving potential and implication for alleviating scarcity, to promote sustainable water use and economic development. Yet due to lack of measured efficiency data, there remains a dearth of water withdrawal accounting methods and datasets, as well as water availability and scarcity data, no matter for total or sectoral amounts for prefectural cities. These data limitations from water statistics and accounting in China are significant, long-lasting for two decades (typically data from 1995 are still being utilized in research, and urgently need to be updated). Compared to developed countries, such as Australia etc., water accounting in China has already fallen behind. Disaggregated sectoral water withdrawal accounting is not readily available for China. Not all cities in China have the water accounting as ‘routine’ management activities. Approximately one fifth of 343 cities do not collect or develop water data statistics (with no bulletins). For data of the other four fifths of cities, there are only total numbers of six types provided (with differences in terms of statistical calibers etc.). New accounting methodology is needed to develop, which should be suitable for new cases according to specific statistical conditions of different sectors, and China’s own actual state. This is quite different from developed countries. Water withdrawal statistics in China are patchy, and water data across all sectors at the city level appear to be relatively insufficient. Hence, in administrative and territorial scopes, I develop a general framework to, for the first time, account for water withdrawal of 65 economic-social-environmental sectors in cities of China. This novel methodology is based on water withdrawal efficiency, as benchmark performance, from point-sourced surveys in China (led and carried out by the Ministry of Ecology and Environment) in 2015. It features in selection of 22 driving forces, and I connect each size indicator with its unique water-withdrawal efficiency. The general framework is applied because only inconsistent water statistics collected from different data sources at the city level are available. Applying this general framework, I account for water withdrawal of all 65 economic-socio-environmental sectors for all 343 prefectural cities in China, using a 2015 data benchmark. Then I compare different scopes and methods of official accounts and statistics from various water withdrawal datasets. I further account for total water availability, and water scarcity status in each of 343 prefectures. These high-resolution water accounts in terms of spatiality and economic-sector are unprecedented in China. From the water withdrawal datasets, I first find 1) different from conventional perceptions that agriculture is usually the largest water user, industrial and household water withdrawal may also account for the largest percentages in the water-use structure of some cities, for example Luoyang (central) for industrial water withdrawal; and Guangzhou (south) and Qingdao (east) for household water withdrawal. 2) The difference among annual household water use per resident in the urban areas of different cities is relatively small (as is the case for rural areas), but that between urban and rural areas is large. Thus, increased attention should be paid to controlling industrial and urban household water use in particular cities, such as Xi’an (west), Shaoxing (east), Taizhou (east), Luoyang (central), and Chongqing (southwest). These high-resolution water scarcity accounts throw light upon cities suffering from water scarcity, and low water-efficiency sectors at the city level: I find 3) agricultural and industrial sectors with high water-withdrawal intensity exist in representatively small developing cities. 4) The top 10% of low-efficiency industrial sectors represent 46% industrial water withdrawal. Examples of 3) and 4) are listed below: papermaking and product manufacturing in Chenzhou (central), Lincang (southwest) and Qiqihar (northeast); liquor, beverage and tea manufacturing in Jingdezhen (mid-east), Anqing (mid-south) and Wuzhou (southwest); electricity and hot water supply in Changde (mid-south); and agricultural-related sectors in Zhoukou (central), Linyi (east) and Fuyang (mid-south). Thus, attention should also be paid to both coordinating production scales in water-scarce cities, and reducing water withdrawal intensities for stringent management. What is more, to investigate sectoral water-saving potential and implication for alleviating stress, I build water-saving scenarios in 41 industrial and 5 agricultural sectors across 180 water-scarce cities, by assuming a convergence of below-average efficiencies to the national sector-average for technology improvement. I find overall industrial water-withdrawal efficiency could improve by 20%, satisfying the redline regulation. 18.9 km3 (±3.2%) water saving in industry and 50.3 km3 (±2.3%) in agriculture would be achieved, equivalent to the annual water demand of Russia. A minority of sectors could contribute to most water savings whilst minimizing economic disruptions. In contrast, implementing water efficiency measures in the majority of sectors would result in significant economic change to achieve identical savings. As a result, water efficiency improvements should be targeted towards this minority of sectors: cloth(ing) and chemical manufacturing in industry, and rice, vegetables and fruits cultivation in agriculture. Cities with above-average water saving potential are Suzhou (south), Nanjing (southeast), Xiangtan (mid-south), Guangzhou (south) and so on for industry; Bayannur (north), Kashi (northwest), Akesu (northwest), and Daqing (northeast) etc. for agriculture. There would be 18 cities with population of 40 million alleviated below the scarcity threshold (40%) and shake off water scarcity at identical water availability levels, for example Xining, Zhangye, Hotan, Haidong (northwest), Jincheng, Yulin (west), Jilin city (northeast), Wuxi and Xiangtan (mid-south). At the national level, mean scarcity level of water-scarce cities would fall by 20 percentage points from 96% to 76%, being alleviated to sub extreme-scarcity level. Through unique account, I propose that sectoral water saving should be well positioned to alleviate water stress, through improving sectoral water use efficiency, especially by reducing sectoral water withdrawal intensities with little cost to the economy. I think sectors of low efficiency in water scarce cities should be well-targeted. Requiring all sectors to evenly or in-general improve water efficiency does not represent an optimal policy choice. In sum, this complete analysis through unique account would bring a conceptual advance. Our results help to enable targeted saving strategies and identify priorities, to facilitate more effective water regulation through optimizing efforts for improving efficiency. At last, these geo-data of high resolution could be used directly in input-output models, consumption-based accounting and structural decomposition analyses. The data accounted would facilitate proceeding to in-depth exploration. Data could also help gain in-depth insights, concerning sectoral water withdrawal, and alleviating water stress from local activities

Quantity and quality of China's water from demand perspectives

China is confronted with an unprecedented water crisis regarding its quantity and quality. In this study, we quantified the dynamics of China's embodied water use and chemical oxygen demand (COD) discharge from 2010 to 2015. The analysis was conducted with the latest available water use data across sectors in primary, secondary and tertiary industries and input-output models. The results showed that (1) China's water crisis was alleviated under urbanisation. Urban consumption occupied the largest percentages (over 30%) of embodied water use and COD discharge, but embodied water intensities in urban consumption were far lower than those in rural consumption. (2) The 'new normal' phase witnessed the optimisation of China's water use structures. Embodied water use in light-manufacturing and tertiary sectors increased while those in heavy-manufacturing sectors (except chemicals and transport equipment) dropped. (3) Transformation of China's international market brought positive effects on its domestic water use. China's water use (116-80 billion tonnes (Bts))9 and COD discharge (3.95-2.22 million tonnes (Mts)) embodied in export tremendously decreased while its total export values (11-25 trillion CNY) soared. Furthermore, embodied water use and COD discharge in relatively low-end sectors, such as textile, started to transfer from international to domestic markets when a part of China's production activities had been relocated to other developing countries

City-level water withdrawal in China:Accounting methodology and applications

In the context of the freshwater crisis, accounting for water withdrawal could help planners better regulate water use in different sectors to combat water scarcity. However, the water withdrawal statistics in China are patchy, and the water data across all sectors at the city level appear to be relatively insufficient. Hence, we develop a general framework to, for the first time, estimate the water withdrawal of 58 economic–social–environmental sectors in cities in China. This methodology was applied because only inconsistent water statistics collected from different data sources at the city level are available. We applied it to 18 representative Chinese cities. Different from conventional perceptions that agriculture is usually the largest water user, industrial and household water withdrawal may also occupy the largest percentages in the water-use structure of some cities. The discrepancy among annual household water use per capita in the urban areas of different cities is relatively small (as is the case for rural areas), but that between urban and rural areas is large. As a result, increased attention should be paid to controlling industrial and urban household water use in particular cities. China should specifically prepare annual water accounts at the city level and establish a timetable to tackle water scarcity, which is a basic step toward efficient and sustainable water crisis mitigation

City-level water-energy nexus in Beijing-Tianjin-Hebei region

Water-energy nexus in a city can either prompt or undermine its development. Yet in China, the relevant research is rarely found. This study accounts the city-level water-energy nexus in Beijing-Tianjin-Hebei region in 2012 from both production and consumption perspectives, where input-output analysis based on city-level input-output tables are applied to conduct consumption-based accounts. Regarding water for energy, Beijing, Tianjin and Tangshan occupy the largest amounts of water for production in the energy sector, at 203 million tonnes (Mt), 148 Mt and 118 Mt, and they also consume most water for energy, at 6690 Mt, 1328 Mt and 1476 Mt. In terms of energy for water, Shijiazhuang and Tianjin have the largest amounts of CO2 emissions for production and consumption respectively, at 28 thousand tonnes (Kt) and 1746 Kt. Furthermore, local authorities should prioritise electricity sector as it holds 69% and 72% of the total water amounts for production and consumption in the energy sector. Besides, integrated management is crucial for cities with low water and energy efficiency (Baoding and Zhangjiakou), and for large CO2 emitters in Hebei province in order to ensure their water and energy sustainability without stunting their economic growth

Rb-Sr Isotopic Geochronology and Geological Implications of Dongfeng Gold Deposit in Jiaodong Area

The superlarge Dongfeng gold deposit is located in the Potouqing faults-alteration belt of the eastern part of the ‘Zhao-Lai-gold ore belt’, which belongs to the northwestern part of the Jiaodong area. Tectonically, ore bodies are controlled by faults and gold mainly occurs in the pyrite and polymetallic sulfide-bearing quartz vein. In this paper, Rb–Sr isotopic analysis is carried out with the beresite, which formed by hydrothermal metasomatism, and the Rb–Sr isochron age is 125.5±6.7Ma, indicating this deposit set up in the early Cretaceous of the late Yanshanian. Based on the relationship between the Dongfeng gold deposit and the Mesozoic granite, it is suggested that the formation of the gold deposit is a complex geological process of gradual enrichment and precipitation of the ore-forming elements. The initial 87Sr/86Sr ratio of the beresite is 0.711502±0.000069, which indicates the ore-forming materials mainly come from the crust. Combined with the complex mineralization process of the Dongfeng gold deposit and the reported H-O isotopic data, it is suggested that the ore-forming materials are mainly derived from the crust with some mantle materials, while the ore-forming fluids are originated primarily from magmatic hydrothermal and mantle with some precipitate water

City level water withdrawal and scarcity accounts of China

In the context of China’s freshwater crisis high-resolution data are critical for sustainable water management and economic growth. Yet there is a dearth of data on water withdrawal and scarcity regardless of whether total or subsector amount, for prefectural cities. In administrative and territorial scope, we accounted for water withdrawal of all 63 economic-socio-environmental sectors for all 343 prefectural cities in China, based on a general framework and 2015 data. Spatial and economic-sector resolution is improved compared with previous studies by partitioning general sectors into industrial and agricultural sub-sectors. Construction of these datasets was based on selection of 16 driving forces. We connected a size indicator with corresponding water-withdrawal efficiency. We further accounted for total blue-water withdrawal and quantitative water scarcity status. Then we compared different scopes and methods of official accounts and statistics from various water datasets. These disaggregated and complete data could be used in input-output models for municipal design and governmental planning to help gain in-depth insights into subsector water-saving priorities from local economic activities

De novo transcriptome analysis of Medicago falcata reveals novel insights about the mechanisms underlying abiotic stress-responsive pathway

BACKGROUND: The entire world is facing a deteriorating environment. Understanding the mechanisms underlying plant responses to external abiotic stresses is important for breeding stress-tolerant crops and herbages. Phytohormones play critical regulatory roles in plants in the response to external and internal cues to regulate growth and development. Medicago falcata is one of the stress-tolerant candidate leguminous species and is able to fix atmospheric nitrogen. This ability allows leguminous plants to grow in nitrogen deficient soils. METHODS: We performed Illumina sequencing of cDNA prepared from abiotic stress treated M. falcata. Sequencedreads were assembled to provide a transcriptome resource. Transcripts were annotated using BLASTsearches against the NCBI non-redundant database and gene ontology definitions were assigned. Acomparison among the three abiotic stress treated samples was carried out. The expression of transcriptswas confirmed with qRT-PCR. RESULTS: We present an abiotic stress-responsive M. falcata transcriptome using next-generation sequencing data from samples grown under standard, dehydration, high salinity, and cold conditions. We combined reads from all samples and de novo assembled 98,515 transcripts to build the M. falcata gene index. A comprehensive analysis of the transcriptome revealed abiotic stress-responsive mechanisms underlying the metabolism and core signalling components of major phytohormones. We identified nod factor signalling pathways during early symbiotic nodulation that are modified by abiotic stresses. Additionally, a global comparison of homology between the M. falcata and M. truncatula transcriptomes, along with five other leguminous species, revealed a high level of global sequence conservation within the family. CONCLUSIONS: M. falcata is shown to be a model candidate for studying abiotic stress-responsive mechanisms in legumes. This global gene expression analysis provides new insights into the biochemical and molecular mechanisms involved in the acclimation to abiotic stresses. Our data provides many gene candidates that might be used for herbage and crop breeding. Additionally, FalcataBase (http://bioinformatics.cau.edu.cn/falcata/) was built for storing these data. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12864-015-2019-x) contains supplementary material, which is available to authorized users

Allosteric control of an asymmetric transduction in a G protein-coupled receptor heterodimer

GPCRs play critical roles in cell communication. Although GPCRs can form heteromers, their role in signaling remains elusive. Here we used rat metabotropic glutamate (mGlu) receptors as prototypical dimers to study the functional interaction between each subunit. mGluRs can form both constitutive homo- and heterodimers. Whereas both mGlu2 and mGlu4 couple to G proteins, G protein activation is mediated by mGlu4 heptahelical domain (HD) exclusively in mGlu2-4 heterodimers. Such asymmetric transduction results from the action of both the dimeric extracellular domain, and an allosteric activation by the partially-activated non-functional mGlu2 HD. G proteins activation by mGlu2 HD occurs if either the mGlu2 HD is occupied by a positive allosteric modulator or if mGlu4 HD is inhibited by a negative modulator. These data revealed an oriented asymmetry in mGlu heterodimers that can be controlled with allosteric modulators. They provide new insight on the allosteric interaction between subunits in a GPCR dimer

Rb-Sr Isotopic Geochronology and Geological Implications of Dongfeng Gold Deposit in Jiaodong Area

The superlarge Dongfeng gold deposit is located in the Potouqing faults-alteration belt of the eastern part of the ‘Zhao-Lai-gold ore belt’, which belongs to the northwestern part of the Jiaodong area. Tectonically, ore bodies are controlled by faults and gold mainly occurs in the pyrite and polymetallic sulfide-bearing quartz vein. In this paper, Rb–Sr isotopic analysis is carried out with the beresite, which formed by hydrothermal metasomatism, and the Rb–Sr isochron age is 125.5±6.7Ma, indicating this deposit set up in the early Cretaceous of the late Yanshanian. Based on the relationship between the Dongfeng gold deposit and the Mesozoic granite, it is suggested that the formation of the gold deposit is a complex geological process of gradual enrichment and precipitation of the ore-forming elements. The initial 87Sr/86Sr ratio of the beresite is 0.711502±0.000069, which indicates the ore-forming materials mainly come from the crust. Combined with the complex mineralization process of the Dongfeng gold deposit and the reported H-O isotopic data, it is suggested that the ore-forming materials are mainly derived from the crust with some mantle materials, while the ore-forming fluids are originated primarily from magmatic hydrothermal and mantle with some precipitate water