Migratory behaviour and survival rates of wild northern Atlantic salmon Salmo salar post‐smolts: effects of environmental factors

To study smolt behaviour and survival of a northern Atlantic salmon Salmo salar population during river descent, sea entry and fjord migration, 120 wild S. salar were tagged with acoustic tags and registered at four automatic listening station arrays in the mouth of the north Norwegian River Alta and throughout the Alta Fjord. An estimated 75% of the post‐smolts survived from the river mouth, through the estuary and the first 17 km of the fjord. Survival rates in the fjord varied with fork length (L_F), and ranged from 97·0 to 99·5% km^?1. On average, the post‐smolts spent 1·5 days (36 h, range 11–365 h) travelling from the river mouth to the last fjord array, 31 km from the river mouth. The migratory speed was slower (1·8 L_F s^?1) in the first 4 km after sea entry compared with the next 27 km (3·0 L_F s^?1). Post‐smolts entered the fjord more often during the high or ebbing tide (70%). There was no clear diurnal migration pattern within the river and fjord, but most of the post‐smolts entered the fjord at night (66%, 2000–0800 hours), despite the 24 h daylight at this latitude. The tidal cycle, wind‐induced currents and the smolts' own movements seemed to influence migratory speeds and routes in different parts of the fjord. A large variation in migration patterns, both in the river and fjord, might indicate that individuals in stochastic estuarine and marine environments are exposed to highly variable selection regimes, resulting in different responses to environmental factors on both temporal and spatial scales. Post‐smolts in the northern Alta Fjord had similar early marine survival rates to those observed previously in southern fjords; however, fjord residency in the north was shorter.     

东江流域景观格局对氮、磷输出的影响

基于实地采样水质数据与遥感解译所得土地利用数据,采用相关分析和冗余分析,从时间和空间两个尺度,探讨东江流域景观格局与氮、磷输出的关系。结果表明：（1）城镇和水域面积占比与河流氮磷含量正相关,林地和草地面积占比与河流氮磷含量负相关。（2）景观分裂指数（DIVISION）、香浓多样性指数（SHDI）、散布与并列指数（IJI）、边缘密度（ED）和斑块密度（PD）等景观指数与河流氮磷含量呈正相关关系,最大斑块指数（LPI）、蔓延度指数（CONTAG）和相似邻近比例（PLADJ）与河流总氮总磷含量负相关。（3）平水期河流水质与景观格局的相关性强于丰水期;从空间尺度来看,集水区尺度与河流水质的相关性好于缓冲区尺度;此外,总氮对于景观格局的响应比总磷更敏感。     

Circulation and the nutrient budget in Myall Lakes

A two-dimensional model is used to study transport of material within Myall Lakes and is coupled to the ocean using a one-dimensional model of Lower Myall River. Runoff from the catchment is calculated from water levels and compares favourably with rainfall assuming an average runoff yield of 28% and a runoff coefficient of 47% for events above the 90th percentile. Most of the runoff enters Bombah Broadwater which is also the only basin connected to the ocean. Intermittent runoff events rapidly displace water from Bombah Broadwater into Boolambayte Lake and from Boolambayte Lake into Myall Lake. Displaced water is mixed within basins by wind-driven circulation within the time scale that levels fall as water drains from the lakes to the ocean. Only 7% of the nutrient load entering Bombah Broadwater becomes resident Myall Lake. About 40% of the nutrient load entering Boolambayte Lake becomes resident in Myall Lake. Median time scales for loss of conservative material entering each basin with the runoff are: 140 days for Bombah Broadwater, 118 days for Boolambayte Lake, and 535 days for Myall Lake. Salinity fluctuates greatly in Bombah Broadwater but is stable in Myall Lake. Material loss from Bombah Broadwater is characterized by many time scales associated with runoff from the catchment and low-frequency changes in ocean water level. Comparison of observed distributions of total nitrogen with simulations indicates that there are sources of total nitrogen in Boolambayte Lake and Myall Lake and sinks of total nitrogen in Bombah Broadwater. There appear to be sinks of total phosphorus throughout the Myall Lakes.     

The Water Framework Directive’s “percentage of surface water bodies at good status”: unveiling the hidden side of a “hyperindicator”

The Water Framework Directive (WFD) has provided the means of standardizing the way surface water bodies are monitored throughout the European Union (EU), using a common evaluation measure, the percentage of surface water bodies at good status, based largely on the structure and functioning of aquatic ecosystems. However, the evaluation of good status is based on the way the WFD is implemented, which differs in each country. In this article, we analyze how the WFD is implemented in France, how the water agencies divide up the water bodies, the areas covered by their monitoring networks, and the modalities of obtaining data to provide the EU with the percentage of water bodies at good status. This analysis reveals that it is this hyperindicator itself that is at stake, obtained by successively aggregating values measured in time and space, from the monitoring station to the River Basin District (RBD), reducing vast amounts of information to a single measure per RBD, while long-term monitoring of the major European rivers and their sedimentary budgets, which show improvements in certain quality aspects, are largely overlooked by the WFD. When drawing up the indicator, the agencies identify certain biases but not others. This raises the question of its use and relevance for managers and politicians, at both national and European level.     

基于动态测算模型的跨界生态补偿标准——以新安江流域为例

针对目前跨界生态补偿普遍存在的补偿标准单一、补偿内容不完善等问题,以新安江流域为例,构建基于机会成本法和生态系统服务价值法的动态测算模型,开展跨界生态补偿标准研究。根据目前新安江流域各阶段协议水质将生态补偿分为试行和修复两个测算阶段,补偿年限分别为2012-2014年和2015-2017年。试行阶段采用机会成本法,修复阶段采用生态系统服务价值法。结果表明：（1）试行阶段新安江流域生态补偿的直接成本和间接成本额度分别从2012年的18.49亿元和2.28亿元上升到2014年的32.47亿元和4.01亿元。其中,工业在间接成本中年均占比率高达55.10%,这说明黄山市从多方面逐渐加强对流域的生态管理和投入,尤其是对流域水生态环境起直接影响的污染企业采取了取缔关停等措施。（2）2015-2017年新安江流域生态补偿额度也呈现上涨态势。黄山市总供给和自身消耗的生态系统服务价值的年均增幅分别为5.08%和4.32%,生态系统服务价值总供给比自身消耗高0.76个百分点,反映出黄山市通过增加生态面积、改变土地利用类型等方式来提高流域水生态环境质量。（3）新安江流域2012-2014年试点阶段的生态补偿总额应为80.67亿元,2015-2017年修复阶段的生态补偿总额应为125.65亿元。而实际新安江流域试点以来累计投入36亿元的生态补偿额,远低于上游对环境整治的投入与损失额,因此建议为了新安江流域的生态环境保护,流域双方建立动态、长效的生态补偿机制,加大生态补偿额度。     

Developing an understanding of dissolved organic matter dynamics in the giant Lake Baikal by ultrahigh resolution mass spectrometry

To elucidate the molecular characteristics of dissolved organic matter (DOM) in Lake Baikal, 3D excitation-emission matrix spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) were employed. From the linear relationship between the humic-like peak intensities (excitation/emission = 305 nm/430 nm) and dissolved organic carbon (DOC) concentrations in the water samples extending from the Selenga River mouth to offshore (central lake in the south basin), allochthonous DOM appeared to be a main contributor to the DOC concentrations. However, DOM with fewer fluorophores dominated in the South Basin of the lake at stable DOC concentrations of ca. 0.84 mg C l^?1. Meanwhile, FT-ICR MS analysis and subsequent principal component analysis across the transect revealed a transition of compounds with high H-deficiency (aromatic) to compounds with low H-deficiency (aliphatic) that dominate pelagic open-lake water. We believe that this molecular change is induced by photo-degradation, which mainly alters aromatic compounds.     

1995-2014年拉萨河流域水环境变化及其驱动力

探究自然环境和人类活动影响下的河流水环境变化,对于流域水资源管理和保护有重要意义。目前从较长时间尺度上系统开展拉萨河流域水环境的研究较少,基于拉萨河流域达孜、卡林、才纳3个环境监测中心站近20年（1995-2014）的水质资料,综合单因子指数法和内梅罗指数法评估拉萨河流域水环境状况,并采用Mann-Kendall检验法分析其多年变化趋势。同时,从经济社会和自然环境两个方面通过灰色关联分析法识别了影响流域水环境变化的关键驱动因子,以期为流域水环境保护提供借鉴。结果表明：（1）总体上,拉萨河流域水环境状况良好,满足水功能区要求;（2）水体中pH、溶解氧、化学需氧量、总磷等指标的取值较高,在0.7左右,是拉萨河流域水环境需重点关注指标;（3）水环境质量稍有下降,内梅罗指数从1995年的0.62增加到2014年的0.73;（4）近20年来拉萨河流域水环境变化的主要驱动因子为降水量、牲畜存栏数、人口数、农村人口数和国民经济生产总值等,农牧非点源污染是拉萨河流域的主要污染源,要重点关注和管控。     

Integrated Constructed Wetlands (ICW) working at the landscape scale: The Anne Valley project,Ireland

Availability of clean water in Europe has become a topic of great concern. The Water Framework Directive (WFD) is putting pressure on EU Member States to provide water quality of a high standard throughout the Union. An effective way of tackling this problem is to use Integrated Constructed Wetlands (ICWs) at the landscape scale. Over the last 23 years, 15 ICWs have been constructed within the Anne Valley catchment in Waterford, Ireland, to address both point-source and diffuse pollution at the catchment scale. ICWs address a diversity of pollution problems including the treatment of sewage effluent from small villages, wastewater from livestock and waste material from creameries. A series of aerial photographs shows the development of these wetlands within the catchment over time. A catchment scale GIS is currently being developed in Ireland to address the WFD concerns. The integration of ICWs into these catchment models will provide a mechanism for measuring their effectiveness at the landscape scale and for identifying strategic sites for their implementation.     

Erosion and sediment yield in the Atna river basin

Variability in suspended sediment transport and its relation to erosion processes in two different catchments within the Atna river basin are discussed on the basis of 14 years of data collection. The upper Atna catchment is a headwater system covering 157 km². Extensive glacifluvial deposits are the main sediment source of the river. Sediment transport in the upper Atna during 1988–2001 ranged from 79.4 t to 13,200 t. The extreme upper value was due to an extreme rainflood in 1996. Suspended sediment concentrations varied from less than 1.0 mg l^?1 to a maximum of 2023.8 mg l^?1. There was no correlation between water discharge and suspended sediment concentration. Despite a fairly constant volume of total runoff, sediment concentrations remained at a high level during the first years after extreme floods, and then decreased over several more years. The complicated pattern of short term and long term variations in suspended sediment concentration and load was explained in terms of channel changes and variations in exposure of the sedimentary deposits to fluvial erosion. The catchment of the lower Atna drains an area of 672 km². Concentrations of inorganic suspended sediments were found to vary between <1.0 and 897 mg l^?1, with only a weak correlation to water discharge. The suspended sediment transport per year ranged from a minimum value of 574 t in 1991 to 60,651 t per year in 1995, the extreme flood year. The mean annual transport for all the years was 6271 t. The sediment transported in the lower Atna is derived from the same types of sources as in the upper catchment, but the sediments are supplied from a larger area. Grain size distribution analyses indicate that the transported sediments in upper Atna have a sand content of 10 to 65% compared to 2–20% in lower Atna. The transport of particulate organic matter in the upper and lower Atna catchments amounted to 9.8% and 12.6% of the total load, respectively.     

Small-scale Gold Mining in the Puyango River Basin,Southern Ecuador: A Study of Environmental Impacts andHuman Exposures

This study addresses the impact of small-scale gold mining on the environment and communities of the Puyango River basin in the southwest of Ecuador between 1999 and 2001. Our primary objectives were to measure mercury, manganese, and lead in the river, to identify pathways of population exposure, and biological indicators of human exposure. A multi-method design at the catchment scale was applied to the analysis of water, sediments, and particulate matter for mercury, lead, and manganese over two different seasons. A household survey was undertaken, and individuals were assessed for lead (blood samples), and for mercury (urine and hair samples). River water samples had high concentrations of particulate matter (700 mg/L). Mercury and lead levels in water at the gold processing plants were very high in both seasons (250 ng Hg/L and 160 μg Pb/L). Mercury and lead, there was a downstream gradient with the areas adjacent to the gold processing plants having the highest levels. In Portovelo, the Upper Basin city, 14% of the population reported occupational exposure to inorganic mercury. Although no one in Portovelo consumes water from the river, 10% of the population consume local fish. This contrasts the Lower Basin where 98% of the population consume fish, and 100% use river water for drinking and cooking. Lead blood levels over 20 μg/dl were found in 39.4% of the study population and blood mercury over 10 μg/L only in 10.0%. Urinary mercury over 4 μg/L was found in 66.5% of the examined persons. Hair methylmercury did not exceed the safe limit of 2 μg/g, the mean concentration was 1.2 μg/g. Mining activity and erosion contributes to heavy-metal contamination (mercury, lead, and manganese) throughout the Puyango Basin. The relation between environmental contamination is complex and further research is being conducted to understand these relations.     

Early marine migration of European silver eel Anguilla anguilla in northern Norway

To study the migratory behaviour in wild northern European silver eel Anguilla anguilla during sea entry and early marine migration, 32 individuals were tagged with acoustic transmitters and registered at four automatic listening station arrays from the mouth of the north Norwegian River Alta and throughout the Alta Fjord. The A. anguilla entered the fjord during all parts of the tidal cycle and did not seem to utilize the outgoing tidal currents. They migrated mainly during the night, in both the river mouth and the fjord. On average, they spent 2·7 days travelling from the river mouth to the outermost array, 31 km from the river mouth, corresponding to an average migratory speed of 0·5 km h(-1) . The A. anguilla generally migrated in the central part of the fjord and in the uppermost 10-25% of the water column, but with frequent dives to greater depths. Already 4 km after sea entry, A. anguilla were observed diving deeper than 130 m within 20-30 min periods. Hence, this study demonstrated that A. anguilla may perform an active diving behaviour during the early marine migration. The study took place in a pristine area with a minimum of anthropogenic interventions and by individuals from a population still uninfected by the introduced parasite Anguillicoloides crassus. The results may therefore be used as a baseline for future studies of the A. anguilla early marine migration.     

长江流域实际蒸散发演变趋势及影响因素

长江流域是我国重要的水资源供给区域,流域生态系统的水资源供给不仅服务于流域内部,同时也通过南水北调服务于北方部分地区。实际蒸散发作为地表水文循环重要环节会直接影响到生态系统的水资源供给服务能力。在全球气候变暖与地表环境变化的背景下,分析长江流域实际蒸散发的演变趋势与成因,对于我国水资源供给和生态安全的保障有着重要的意义。在对比GLEAM_v3.2a、MOD16、GLDAS_Noah2、ERA_Interim四种常用蒸散发数据集精度的基础上,选择精度最优的GLEAM_v3.2a数据集,通过分段线性拟合、逐步回归和相关性分析了1981-2017年间长江流域地表实际蒸散发演变趋势和影响因素。结果表明：（1）长江流域实际蒸散发的演变具有明显的阶段性,1981-1997年为不显著下降阶段,下降速率为-0.02 mm/a,下降区域主要分布在长江流域西北和东部部分子流域,1998-2017年为全流域显著上升阶段,上升速率为1.94 mm/a;（2）日照时数下降速率减缓、植被指数增加速率升高是长江流域实际蒸散发阶段性变化的主要原因,气温突增、风速回升在长江流域实际蒸散发的长期增加趋势中也起到了重要的正向作用;（3）1998-2017年间,长江流域生态系统水资源供给服务量在实际蒸散发显著增加的影响下有所下降,流域西部地区下降趋势明显,旱情加剧;（4）建议在长江流域西部干旱地区优先加强对本地原生林的保护,同时在生态修复工程中选择针叶乔木等蒸腾能力弱的树种,以缓解旱情加剧的趋势。     

Upstream river morphology and riparian land use overrule local restoration effects on ecological status assessment

River restoration is a central issue of present-day River Basin Management. Unfortunately, many studies have shown limited ecological improvements, hypothesizing catchment influences and missing donor populations as main impeding factors. This study evaluates the ecological status after restoration at 46 river reaches in light of catchment influences upstream. Three groups of environmental parameters were investigated: (i) riparian land use and (ii) physical habitat quality in different lengths upstream of the restorations and (iii) land use in the whole catchment upstream. Ecological quality ratios of standardized fish, invertebrate and macrophyte samples were used as response variables. The results imply that sub-catchment variables influence the ecological status more than local habitat improvements. In particular, fish and invertebrate ecological status was positively linked to percent deciduous forest upstream of restored sites, while macrophytes revealed an opposite trend. Furthermore, we found a strong linkage of site-scale ecological status and physical habitat quality up to 5 km upstream of the restorations; the more natural were riparian land use and river habitat quality upstream, the higher was the chance of a good ecological quality in restored reaches. We conclude that site-scale restoration measures are likely to be unsuccessful, if the sub-catchment physical habitat upstream is degraded.     

基于InVEST模型的黄河流域产水量时空变化及其对降水和土地利用变化的响应

黄河流域是重要的水源涵养和生态屏障区,研究其水源供给服务对实现黄河流域高质量发展和生态环境保护具有重要意义。本研究基于InVEST模型和情景分析法,以土地利用覆被、气象及土壤等数据作为输入,分析了1995—2015年黄河流域产水量的时空格局以及降水变化和土地利用变化对流域产水量的影响,并探讨产水量对二者的响应。结果表明:1995—2015年,黄河流域产水深度增加,增量为24.34 mm,产水高值区集中在西部和西南部,低值区集中在西北区域,产水深度空间格局特征变化不明显;黄河流域三级流域中,龙羊峡以上流域产水量最高,约117 亿m³·a^-1,是黄河流域主要产水区,兰州至河口流域产水量最低,约0.44 亿m³·a^-1;整个流域中永久冰川及雪地的平均产水深度最大,草地是全流域产水总量的主要贡献地类,提供了总产水量的62.6%;降水对产水量的影响比较显著,土地利用/覆被变化对产水量的影响较小。     

Interpreting spatial patterns in redox and coupled water–nitrogen fluxes in the streambed of a gaining river reach

Water pathways through permeable riverbeds are multi-dimensional, including lateral hyporheic exchange flows as well as vertical (upwelling and downwelling) fluxes. The influence of different pathways of water on solute patterns and the supply of nitrate and other redox-sensitive chemical species in the riverbed is poorly understood but could be environmentally significant. For example, nitrate-rich upwelling water in the gaining reaches of groundwater-fed rivers has the potential to supply significant quantities of nitrate through the riverbed to surface waters, constraining opportunities to deliver the goals of the EU Water Framework Directive to achieve ‘good ecological status’. We show that patterns in porewater chemistry in the armoured river bed of a gaining reach (River Leith, Cumbria) reflect the spatial variability in different sources of water; oxic conditions being associated with preferential discharge from groundwater and reducing conditions with longitudinal and lateral fluxes of water due to water movement from riparian zones and/or hyporheic exchange flows. Our findings demonstrate the important control of both vertical and lateral water fluxes on patterns of redox-sensitive chemical species in the river bed. Furthermore, under stable, baseflow conditions (<Q₉₀) a zone of preferential discharge, comprising 20 % of the reach by area contributes 4–9 % of the total nitrate being transported through the reach in surface water, highlighting the need to understand the spatial distribution of such preferential discharge locations at the catchment scale to establish their importance for nitrate delivery to the stream channel.     

滦河流域土壤保持和水质净化服务及其权衡与协同关系

滦河流域是京津冀地区重要的生态屏障和水源涵养区,但流域内仍存在水土流失、河流水质不达标等问题。基于实测资料及loadest模型等工具率定InVEST模型参数,定量评估了滦河流域各生态区2005、2010和2015年土壤保持和水质净化服务及其时空变化特征,采用相关分析和基于网格的Moran′I指数分析了两项服务的作用机理和权衡与协同关系的时空分异,并探讨了气候和土地利用变化对二者的影响。结果表明：2005年、2010年、2015年滦河流域年均土壤保持强度为136.45 t/hm²,时间上呈现出先强增后微减的特点,空间格局表现为由西北向东南增加;流域总氮(TN)、总磷(TP)年均输出量分别为1526.73 t/a和82.89 t/a,输出量逐年增加且集中在流域中下游,流域整体水质净化能力有所减弱。流域内水体中TN、TP浓度与泥沙入河量具有显著相关性,土壤保持和水质净化服务关系整体上由协同向权衡转变,空间上的差异性表现为林地、草地集中区域(生态区A)多以协同关系为主,而农牧带交错地区(生态区B)多以权衡关系为主。建议未来滦河流域开展生态建设和管理工作时应统筹考虑土壤保持...     

Dynamics of a Kalahari long-lived mega-lake system: hydromorphological and limnological changes in the Makgadikgadi Basin (Botswana) during the terminal 50 ka

The Kalahari features a long-lived lacustrine system which may exist since the Early Pleistocene. The emergence of an extant cichlid fish radiation from this (palaeo-) lake during the Middle Pleistocene indicates an ancient lake character. The early history of the system remains speculative, but it is established that lake extensions matching modern Lake Victoria in size have occurred during the Late Pleistocene. It has been assumed that the hydrographical dynamics chiefly depended on the inflow from the Okavango River and thus on ITCZ-controlled precipitation. Our studies, which focused the hydromorphological and palaeolimnological development of the Makgadikgadi Basin during the last 50 ka, suggest that from c. 46–16 ka it did not receive water from the Okavango River but from palaeo-rivers located in the northern and south-western catchment. A northward shift of the winter rainfall zone during the Last Glacial Maximum sustained a high lake level for a period of c. 6 ka. During Heinrich Event 1 (17–16 ka) the lake probably desiccated abruptly and completely. Higher lake levels, controlled by water from the Okavango river system, were reached again during the Holocene before the lake dried up in the middle of the last millennium.     

The recent occurrence,establishment and potential impact of <Emphasis Type="Italic">Geophagus proximus</Emphasis> (Cichlidae: Perciformes) in the Tietê River reservoirs: an Amazonian fish species introduced in the Paraná Basin (Brazil)

The introduction of allochthonous fish species happens constantly in large bodies of freshwater, like as the reservoirs of Paraná Basin, located in Brazilian southeast, representing a threat for local biodiversity. The fish species Plagioscion squamosissimus and Cichla ocellaris were introduced from the 1970s in several water bodies of this basin and had successfully established themselves in all six reservoirs located in the middle and lower Tietê River (SP, Brazil), particularly. After six decades from the first recorded species introduction, this hydrographic system remains open to the invasion of further fish species, owing to widespread fish-farming activity and by the channels opened between this system and other reservoirs and river basin. This study was an effort to confirm the Geophagus proximus occurrence in the six Tietê River reservoirs, verifying the actual introduction status and analyzing its potential environmental impacts on local species by the analysis of the population structure (abundance, body dimensions and feeding habits). By the results, this species was confirmed in the Ibitinga, Nova Avanhandava and Três Irmãos reservoirs. The abundance and feeding analysis shows, respectively, it is successfully established in the Três Irmãos reservoir with the same feeding habitats of local species, such as Geophagus brasiliensis. It was further shown to be very likely that G. proximus would spread throughout the reservoir system of the middle and lower Tietê River, in the manner of P. squamosissimus and C. ocellaris, and the competition pressure for food resources between G. proximus and the local species which represents a potential environmental impact system. These scientific evidences fortifies the knowledge basin for the implantation of a fish management system, to control and reduce the abundance of the invader and to prevent its becoming established in all the Tietê River Basin, avoiding the disastrous consequences for the native species of Paraná River Basin.     

一种改进的中国水资源空间网格化方法

为揭示中国水资源的时空分布格局,引入降水量、干燥度、蒸散发、坡度、植被覆盖度、集水区等6个因素,结合分区权重赋值法,提出了一种改进的对中国水资源空间分配模型。结果表明:基于二级流域的改进水资源空间分配模型对我国具有较高的适用性,其中在三级流域和省级行政单元上的空间分配总体误差分别为7.89%和7.25%。相比黄河流域、淮河流域和西北诸河流域,长江流域、松花江流域和东南诸河流域的水资源空间分配精度更优,其原因在于该区域的水资源空间分布受自然因素(降水量、蒸散发等)影响更为显著。中国水资源空间分布从西北到东南呈增长趋势,这与降水的空间格局基本吻合。南方诸河流域的水资源量主要来源于降水,而冰川融水则是西北诸河流域及多数内陆河流域的主要水源。水资源与国内生产总值(GDP)密度之间的关系随城市规模和地理位置发生变化。这些可为区域水资源管理提供科学依据和数据依据。     

海河流域典型河口生态环境需水量

在分析河口生态环境需水量类型及特征的基础上 ,采用水文学、生物学及水力学方法计算了海河流域中海河口、滦河口及漳卫新河口生态系统水循环、生物循环消耗水量及生物栖息地需水量。考虑不同生态功能需水量间的兼容性 ,得到各河口生态环境需水年度总量 ,以保持河口径流时间分布自然性为基础 ,确定了生态环境需水量年内时间分配。结果表明 ,即使不考虑污染物的排放 ,近年来海河口、漳卫新河口实际径流量已无法满足最低等级生态环境需水量 5 .97和 4 .96亿 m3的要求。相应河口生态系统已发生了不可自然恢复的退化。滦河口径流年度总量基本满足生态环境要求 ,其生态保护重点在于保持生态环境需水量年内时间变化的自然状况。通过比较不同河口间生态环境需水量结果 ,认为河口生态环境需水量空间差异性主要源于河口间气候和径流量的不同 ,时间差异性则受到河口地区年内季节间气候变化幅度的影响。保证污染物达标排放基础上 ,保持河口生态系统蒸发消耗、水体盐度需水量及相应年内时间变化的自然性应成为海河流域河口生态环境保护及恢复工作中的基础