Effects of the "Conversion of Cropland to Forest and Grassland Program" on the water budget of the Jinghe River catchment in China

In 1999 China adopted the "Conversion of Cropland to Forest and Grassland Program" (CCFGP), a nationwide ecological recovery program, to minimize wide-scale soil erosion and vegetation degradation in China, as well as to improve water budgeting results. In the 10 yr since implementation, the CCFGP has resulted in the recovery and reforestation of >100,000 km of cropland and bare land, though the quantitative effect of this program on catchment water budget is not entirely clear. Therefore, we used the Soil and Water Assessment Tool to evaluate and quantify the effects of the CCFGP on the water budget of the Jinghe River catchment, a tributary of the Yellow River covering the central region of the Loess Plateau. Our results indicated that precipitation had dropped by 12.0% from the 1970s (611.6 mm) to the 2000s (538 mm) and that there was a corresponding 25.2% decrease in humidity index from 0.48 to 0.36. Before the CCFGP's implementation, forest and grassland had been decreasing, while bare land, cropland, and shrub land had been increasing. After the implementation of the CCFGP, the opposite trend was observed. Moreover, streamflow increased by about 15 and 20% for the upstream and middle stream subbasins, respectively, while soil water content also showed an obvious increase. Over the same period, evapotranspiration decreased by 5.2 and 13.5 mm and runoff decreased by 37.5 and 38.6% in the two subbasins. The same trends were obtained in the downstream subbasin, where changes were even greater. As a result of the reduced runoff and evapotranspiration, utilization of water resources was more efficient and ecological environment was improved under the CCFGP policy. Our results indicate the CCFGP resulted in a favorable ecological impact and should therefore be maintained.     

Riparian vegetation dynamics and evapotranspiration in the riparian corridor in the delta of the Colorado River, Mexico

Like other great desert rivers, the Colorado River in the United States and Mexico is highly regulated to provide water for human use. No water is officially allotted to support the natural ecosystems in the delta of the river in Mexico. However, precipitation is inherently variable in this watershed, and from 1981-2004, 15% of the mean annual flow of the Lower Colorado River has entered the riparian corridor below the last diversion point for water in Mexico. These flows include flood releases from US dams and much smaller administrative spills released back to the river from irrigators in the US and Mexico. These flows have germinated new cohorts of native cottonwood and willow trees and have established an active aquatic ecosystem in the riparian corridor in Mexico. We used ground and remote-sensing methods to determine the composition and fractional cover of the vegetation in the riparian corridor, its annual water consumption, and the sources of water that support the ecosystem. The study covered the period 2000-2004, a flood year followed by 4 dry years. The riparian corridor occupies 30,000ha between flood control levees in Mexico. Annual evapotranspiration (ET), estimated by Moderate Resolution Imaging Spectrometer (MODIS) satellite imagery calibrated against moisture flux tower data, was about 1.1myr(-1) and was fairly constant throughout the study period despite a paucity of surface flows 2001-2004. Total ET averaged 3.4x10(8)m(3)yr(-1), about 15% of Colorado River water entering Mexico from the US Surface flows could have played only a small part in supporting these high ET losses. We conclude that the riparian ET is supported mainly by the shallow regional aquifer, derived from agricultural return flows, that approaches the surface in the riparian zone. Nevertheless, surface flows are important in germinating cohorts of native trees, in washing salts from the soil and aquifer, and in providing aquatic habitat, thereby enriching the habitat value of the riparian corridor for birds and other wildlife. Conservation and water management strategies to enhance the delta habitats are discussed in light of the findings.     

The effects of large-scale afforestation and climate change on water allocation in the Macquarie River catchment,NSW, Australia

Widespread afforestation has been proposed as one means of addressing the increasing dryland and stream salinity problem in Australia. However, modelling results presented here suggest that large-scale tree planting will substantially reduce river flows and impose costs on downstream water users if planted in areas of high runoff yield. Streamflow reductions in the Macquarie River, NSW, Australia are estimated for a number of tree planting scenarios and global warming forecasts. The modelling framework includes the Sacramento rainfall-runoff model and IQQM, a streamflow routing tool, as well as various global climate model outputs from which daily rainfall and potential evaporation data files have been generated in OzClim, a climate scenario generator. For a 10% increase in tree cover in the headwaters of the Macquarie, we estimate a 17% reduction in inflows to Burrendong Dam. The drying trend for a mid-range scenario of regional rainfall and potential evaporation caused by a global warming of 0.5 degree C may cause an additional 5% reduction in 2030. These flow reductions will decrease the frequency of bird-breeding events in Macquarie Marshes (a RAMSAR protected wetland) and reduce the security of supply to irrigation areas downstream. Inter-decadal climate variability is predicted to have a very significant influence on catchment hydrologic behaviour. A further 20% reduction in flows from the long-term historical mean is possible, should we move into an extended period of below average rainfall years, such as occurred in eastern Australia between 1890 and 1948. Because current consumptive water use is largely adapted to the wetter conditions of post 1949, a return to prolonged dry periods would cause significant environmental stress given the agricultural and domestic water developments that have been instituted.     

Bathymetric and core analysis of the Latrobe River delta to assist in catchment management

In this study, an analysis of bathymetric surveys of the Latrobe River delta conducted in 1879 and 1992 is combined with pollen analysis of cores from the delta sediments to assist in setting management priorities for the Latrobe River catchment, a 5000 km²catchment in the south-east of Australia. Reconstructed delta surfaces from 1879 (not long after European settlement of the area) and 1992 were compared to quantify areas of net erosion and deposition. These were compared to post-European deposition depths determined by the presence of exotic pollen species in the sediment. The results indicated that: (1) average sedimentation rates in the receiving lake for the Latrobe River are less than 1 mm yr⁻¹; (2) the deposited material is fine with no material considered as bedload; and (3) the fine nature of the deposited material makes it suitable for carrying a large load of nutrients. These results created a shift in management focus from concern over sedimentation and erosion in general to a greater emphasis on nutrients. While the integrated management of catchments is implicitly contemporary, it should always be performed within a historical context. Failure to do this can lead to management priorities that do not concur with the facts of catchment response and can therefore result in inefficient resource allocation. The use of studies which provide a historical perspective on the problem are therefore critical.     

Eutrophication of Lake Waters in China: Cost, Causes, and Control

Lake water eutrophication has become one of the most important factors impeding sustainable economic development in China. Knowledge of the current status of lake water eutrophicatoin and determination of its mechanism are prerequisites to devising a sound solution to the problem. Based on reviewing the literature, this paper elaborates on the evolutional process and current state of shallow inland lake water eutrophication in China. The mechanism of lake water eutrophication is explored from nutrient sources. In light of the identified mechanism strategies are proposed to control and tackle lake water eutrophication. This review reveals that water eutrophication in most lakes was initiated in the 1980s when the national economy underwent rapid development. At present, the problem of water eutrophication is still serious, with frequent occurrence of damaging algal blooms, which have disrupted the normal supply of drinking water in shore cities. Each destructive bloom caused a direct economic loss valued at billions of yuan. Nonpoint pollution sources, namely, waste discharge from agricultural fields and nutrients released from floor deposits, are identified as the two major sources of nitrogen and phosphorus. Therefore, all control and rehabilitation measures of lake water eutrophication should target these nutrient sources. Biological measures are recommended to rehabilitate eutrophied lake waters and restore the lake ecosystem in order to bring the problem under control.     

Stakeholders' views towards flood risk management in the Paz River catchment area of Guatemala and El Salvador

The river Paz is a transboundary river that flows through Guatemala and El Salvador. Its frequent floods endanger the lives and livelihoods of downstream communities. Attempts have previously been made to develop flood management programmes for this watershed. However, these approaches were generally made by high-level governmental institutions with few if any contributions from floodplain communities and other stakeholders. Recognising that public consultation is a key aspect in flood management programmes, we intend in this work to extract different stakeholders' views regarding current and future flooding and flood management programmes in the Paz River basin. This is achieved using Future Scenarios Workshops with a projected time horizon of 30 years. The exercise was expected to identify consensual short- and medium–long-term flood management strategies for the Paz River basin that draws on input from inhabitants of flood-prone areas and other stakeholders.     

Floristic Characteristics and Biodiversity Patterns in the Baishuijiang River Basin,China

A case study was conducted on the forest ecosystem in the Baishuijiang River basin of China to reveal the influences of environmental factors and human disturbance on the floristic characteristics and biodiversity patterns. Field surveys of the floristic composition, environmental factors, and disturbance factors were conducted along an elevation gradient, and the relationships between biodiversity pattern and environmental factors were analyzed using CCA (canonical correspondence analysis). The results showed that the floristic composition of higher plants consisted of 197 families, 796 genera, 2165 species, 19 subspecies, 239 varietas, and 12 forma, and it was characterized by the multi-geographic composition and by the transition from tropical to temperate zones. Along an elevation gradient, the variations in α and β diversity were best described by a bimodal curve, and the peak values occurred at middle elevations. The CCA indicated that the elevation had the greatest influence on the biodiversity pattern, followed by the topographic index, slope direction, slope, slope position, slope shape, and vegetation coverage. In addition, human disturbance has greatly impacted the floristic composition and biodiversity patterns, and the biodiversity indices were higher with intermediate disturbance at middle elevations compared to higher and lower disturbances at low and high elevations, respectively. This reflected a disturbance–diversity pattern and thus revealed the obvious importance to maintain the intermediate disturbance for biodiversity conservation.     

A framework for valuing the health benefits of improved bathing water quality in the River Irvine catchment

A simple model predicting bathing water concentrations of Escherichia coli from livestock in the Irvine catchment in SW Scotland has been adapted for intestinal enterococci (IE). This has been used to predict risk of bather illness by extrapolation of published data on bather IE exposure vs incidence of gastro-enteritis. Simulated reduction in the risk of illness by reduced faecal loading was multiplied by a willingness to pay for risk reduction to estimate the annual benefits of mitigation. Health benefits of reducing loading by 75% at Irvine Beach were estimated by a willingness to pay method to be about pound 276k pa. Estimated annualised costs of diffuse pollution mitigation measures across the catchment were higher (> pound 1m), and it is very unlikely that 75% mitigation is achievable with current stocking rates. Further work should explore the influence of uncertainty of model parameters, and use emerging epidemiological information on specific zoonotic pathogens such as E. coli O157 and Cryptosporidium. Other components of the value of clean water should also be included to obtain a complete estimate of the cost:benefit of mitigation.     

Sedimentary Causes and Management of Two Principal Environmental Problems in the Lower Yellow River

Flood and water shortage are two of the leading environmental problems around the world, and among the causes of the problems is sedimentation. The Yellow River brought disastrous floods in its lower reaches in Chinese history. Today, although floods caused by the river are still a formidable hazard hanging over China, it cannot provide the lower reaches with enough usable water. The ineradicable flood hazard and newly emerged water shortage problems of the river are proved to be closely associated with its immense sediment load. The over loaded flow of the river can quickly fill the reservoirs and unceasingly raise the riverbed, attenuating the capacity of reservoirs to suppress floods and provide more water for dry seasons and of river channels to convey floods. Also, the high sediment content pollutes the water and reduces the volume of usable water. In virtue of the intimate linkage between these problems and the formidable sediment load in the river, the solution to these problems should be based on sedimentation management. After reviewing the defects and merits of management measures implemented and proposed, a management scenario composed of multiple measures are recommended. Beside of persistent soil conservation to reduce the huge sediment load, more reservoirs to check sediment and regulate river flows, approaches to alleviating riverbed accretion, interbasin water transfer to mitigate water deficiency, and so on, an emphasis should be laid on use of muddy flows in order to scatter the sediment in a vast area, which was a natural process but has been interrupted by construction of embankments.     

我国入境旅游的收敛状况及原因分析

从经济增长收敛的视角分析我国入境旅游的均衡发展问题,选取1990—2009年我国31个省（市、自治区）的入境旅游人次数据,采用σ收敛方法检验我国入境旅游的收敛情况,并对其原因进行分析。结果表明,我国入境旅游不存在全域性收敛,东部地区存在俱乐部收敛,中部和西部地区呈发散趋势。旅游资源开发是入境旅游收敛的主要原因,突发事件对经济落后地区的短期入境旅游收敛有很大影响,旅游固定资产、人均可支配收入、旅游人力资源供给都不是入境旅游收敛的原因。     

中国南方酸雨的分布特征及其成因分析

本文阐述了酸雨的危害、近几年中国南方地区酸雨的污染的时空分布状况、酸雨的成因等3方面的内容。研究表明：我国南方酸雨区的酸雨污染状况基本上处在一个稳定的时期。降水pH〈5的区域有从长江中上游向长江中下游发展的趋势;在时间分布上,秋季冬季降水pH低,酸雨发生的频率高;春季夏季降水pH高,酸雨发生的频率低。在酸雨的成因上,着重讨论了大气性质、污染物的迁移和扩散、气候条件、大气中颗粒物浓度以及土壤性质对酸雨形成的影响。     

Progress, Challenges and Prospects of Eco-Hydrological Studies in the Tarim River Basin of Xinjiang, China

Eco-hydrological research in arid inland river basins has been a focus of geologists and ecologists as it is crucial for maintaining the sustainable development of socio-economy, particularly in ecologically vulnerable areas. Based on the research work carried out in the Tarim River basin of Xinjiang, northwestern China, this paper summarizes synthetically the climate change and associated responses of water resources in the mountainous area, land use and land cover in the oasis, and plants responding to environmental stresses in the desert area of the river basin. Research gaps, challenges, and future perspectives in the eco-hydrological studies of the Tarim River basin are also discussed.     

Eco-Compensation in Multi-District River Networks in North Jiangsu, China

Eco-compensation is a multi-disciplinary topic. There is no consensus on the issue of river eco-compensation across districts. Although policies regarding river eco-compensation have been issued in China since 2008, due to the high cost, eco-compensation has not been well implemented in the Taihu pilot region. Therefore, a simplified method based solely on water quality (both water quality and water volume included in the Taihu method) was proposed for North Jiangsu province (NJP). However, the formula was flawed and it led to payments being too low. Three problems need to be solved: (1) how to specify the eco-compensation areas; (2) how to test a reasonable eco-compensation model and (3) how to determine the compensation criterion. Solving these issues is already a priority. In this paper, three potential solutions surrounding eco-compensation are discussed: (1) three principles for selecting the representative eco-compensation areas are suggested; (2) the compensation calculation method based on contaminant flux above the ultra standard is revised and (3) a compensation criterion model based on the treatment costs of sewage is proposed. In the NJP case in 2009, the average eco-compensation criterion for chemical oxygen demand (COD) is 2,000 Chinese Yuan (CNY) per ton and ammonia nitrogen (NH₄–N) and total phosphorus (TP) are 8,000 CNY and 80,000 CNY per ton, respectively. Five districts needed to be compensated. The payments in the revised scheme were 4.15–586 million CNY, which were 16–48 times greater than that in the draft method. The new method can provide an important template for managers when drafting river eco-compensation schemes.     

Point- and nonpoint-source pesticide contamination in the Zwester Ohm catchment, Germany

Reducing pesticide loads in surface waters implies identifying the pathways responsible for the pollution. The current study documents the pesticide contamination of the river Zwester Ohm, a 4917-ha catchment in Germany with 41% of the land used for crop production. Discharges and concentrations of 19 pesticides were measured continuously at three locations for 15 mo. The load detected at the outlet of the catchment amounted to 9048 g a.i. The losses represent 0.22% of the pesticides applied by the farmers. The contamination showed a seasonal pattern following the pesticide application times. The wastewater treatment plant system (WWTPS) in the catchment (two wastewater treatment plants [WWTP], 14 combined sewer overflows (CSO), four CSO tanks) emits during dry weather periods purified sewage and during storm events sewage mixed with stormwater runoff into the river. The contribution by the WWTPS to the pesticide load was defined as point-source pollution (PSP). The load was dominated by PSP with at least 77% of the total pollution. No significant interdependencies between intrinsic properties of the pesticides, hydrometeorological factors, and the loads occurring in the stream could be found. Therefore, it is not possible to predict PSP for other catchments based on the results from this study. Whereas 65% of the total load entered the river via the WWTP, a portion of 12% was attributed to the CSO. The study points out that the influence of CSO on PSP should be taken into account in future catchment studies in areas with comparable agricultural structure.     

Water resources and development of women in arid regions in northern China

The total land area in China affected by desertification has grown over time due mainly to rapid population growth and environmental degradation. Arid and semi-arid regions now comprise approximately one-third of the country's land area. Women in arid areas suffer from the harsh environment as well as from discriminatory attitudes tied to the general expectations of women's role in society. Discrimination against women, high rates of illiteracy, poor health care, society's failure to recognize women's work, and insufficient social services result in illness, poverty, and low social status among women. The material poverty and lack of knowledge and education among women living in arid areas are discussed, as well as what women can do to alleviate poverty and improve the environment in arid areas. With regard to policies which could lead to sustainable development, the author discusses improving women's education in arid regions, public policies designed to improve women's conditions, ways to involve women in environmental protection, encouraging migration to reduce environmental degradation, and improving childbearing conditions.     

Nitrogen contamination in the Yellow River basin of China

Nitrogen contamination is one of the most serious problems in the Yellow River of China. This study was conducted to analyze monitoring data on nitrogen contamination for the Yellow River basin in the years 1980, 1990, 1997, and 1999. Several significant results have arisen from the study. First, in conjunction with an increase in economic indexes from the Yellow River's upper basin to its lower basin, the nitrogen concentration in the tributaries also showed an increasing trend from the upper to the lower basin, which, in turn, led to an increase in the nitrogen concentration of the mainstream from the upper to the lower reaches. Second, nitrogen in the river water in the mainstream and the tributaries of the Yellow River was attributed mainly to point sources. In spite of the fact that the ratio of point to nonpoint sources decreased from 2.7 in 1990 to 1.8 in 1997 for total inorganic nitrogen in river water at the Tongguan Station in the lower basin, point sources increased more than nonpoint sources. Third, the ammonium nitrogen and total inorganic nitrogen content of the river water increased significantly in the mainstream and the tributaries during the 1980-1999 period, a change caused by an increase in wastewater discharge and nitrogenous fertilizer application in the Yellow River catchment.     

Water resources and development of women in arid regions in northern China

This paper describes the difficult situation faced by women living in arid areas of China, based on research carried out by the author. She describes the causes and effects of poverty in the targeted areas, and postulates what roles women could play to alleviate poverty and improve the environment in arid areas. In addressing policies which could lead to sustainable development, she discusses improved education in a number of areas; public policies aimed at improving women's conditions; ways to involve women in environmental protection; encouraging migration to reduce environmental degradation; and improving child-bearing conditions.     

Georelational Analysis of Soil Type, Soil Salt Content, Landform, and Land Use in the Yellow River Delta, China

The Yellow River Delta, one of China’s three major river deltas, is becoming a major region for the development of agriculture and fisheries. Protecting the delicate ecology of newly formed aquatic systems as well as the evolution of soils, natural vegetation, and fauna on older upland environments in the delta is a priority in planning for the wise use of the delta’s resources for future agricultural development. In this article, we use a Geographic Information System (GIS) to analyze relationships between land-use/land-cover characteristics in the Dongying municipality, one of the most intensely developed areas of the delta, and spatial variations in soil salinity and landforms. This analysis reveals that soil salt content decreases from regionally high values in isolated depressions to relatively moderate values in embanked former back swamps, with the lowest values occurring in abandoned river courses. Comparing the present land use on this soil salinity–landform pattern shows that it is basically at odds with general concepts of land suitability for agricultural utilization of saline soils. Crop-based agriculture in the region is probably overdeveloped, whereas more appropriate agricultural development, like cattle and forest production, is underrepresented. Future development should focus on converting farmland in embanked former back swamps and abandoned river courses into grasslands and forests. Crop-based agriculture (up to 151,000 ha) could be planned at the low-salinity terrace uplands and flood plains. The article provides guidelines for decision-makers regarding agricultural land use and wetland protection in the Yellow River Delta.     

Land Use and Land Cover Change Analysis and Prediction in the Upper Reaches of the Minjiang River,China

Scientists have aimed at exploring land use and land cover change (LUCC) and modeling future landscape pattern in order to improve our understanding of the causes and consequences of these phenomena. This study addresses LUCC in the upper reaches of Minjiang River, China, from 1974 to 2000. Based on remotely sensed images, LUCC and landscape pattern change were assessed using cross-tabulation and landscape metrics. Then, using the CLUE-S model, changes in area of four types of land cover were predicted for two scenarios considering forest polices over the next 20 years. Results showed that forestland decreased from 1974 to 2000 due to continuous deforestation, while grassland and shrubland increased correspondingly. At the same time, the farmland and settlement land increased dramatically. Landscape fragmentation in the study area accompanied these changes. Forestland, grassland, and farmland take opposite trajectories in the two scenarios, as does landscape fragmentation. LUCC has led to ecological consequences, such as biodiversity loss and lowering of ecological carrying capacity.