Palaeoenvironmental reconstruction at an oxbow lake situated at the lower Nottawasaga River,southern Ontario,Canada

Abstract

The purpose of this investigation at the lower Nottawasaga River in southern Ontario, Canada, was to reconstruct the impact of base level on fluvial stability and human occupation during the Holocene in a topographically confined section, where the river cuts through the Edenvale Moraine. Three cores were extracted from an oxbow lake (Doran Lake) and a ground-penetrating radar survey was executed in its vicinity to study wider subsurface alluvial architecture. Radiocarbon dating suggests that the Nottawasaga River became entrenched in the Edenvale Moraine early in the Holocene, with base-level lowering in the Lake Huron basin, and that Doran Lake formed towards the middle Holocene as a meander cutoff when water levels in the Lake Huron basin increased, leading to a period of fluvial instability, enhanced flow and floodplain aggradation. Fluctuating lake levels would have affected human settlement as well as the preservation and visibility of archaeological remains predominantly through vertical accretion.     

近300年来新疆玛纳斯湖变迁研究

本文在充分分析、利用历史文献记载、精确解读历史地图信息的基础上,结合现代大比例尺地形图、遥感卫星影像资料,以及前人的科学研究和野外实地考察成果,运用历史地理逆向推演法,分析了近300年来玛纳斯湖的历史演化过程,确定了不同历史时期玛纳斯湖的地理位置,弥补了第四纪以来玛纳斯湖演化过程研究的空白,并且对不同历史时期区域自然因素与人文因素对玛纳斯湖流域水文变迁的影像进行了分析,为今后玛纳斯湖周围生态环境演化研究提出了新的研究重点和研究方向。     

清代东太湖地区的湖田与水文生态

清代的东太湖地区的湖田出现了快速增长。随着山区水土流失,东太湖的泥沙量大增,水面植被也出现大扩展,淤积和湖田扩展也因此加速。在西部出现大缺口,大缺口在清代很快合拢。东部湖田发展使出太湖的水流受阻,吴淞江北移瓜泾口,进而使东北部湖田快速发展。湖田形成时往往先是大圩,后是小圩,以后逐步形成纵向交错的河网。植桑又加速了湖田水稻土的培肥,优良的水稻土在小圩规模上逐步形成。植桑养蚕与稻作的配合维持了传统江南生态农业的持续。     

寻迹西湖 西湖的历史云山

杭州西湖,位于浙江省杭州市老城区的西部因此而得"西湖"之名,自东汉西湖形成以后的近四百年间,钱塘县不断生聚.扩展,至6世纪,杭州诞生。隋代江南运河的开凿,杭州城成为运河的终点,就此一跃成为一个商业城市,并迅速发展。"西湖"之名,大概始于隋代,至唐代已被频繁使用,也是从这个时候,杭州开始迅速发展。至唐代李泌开凿六井,引西湖淡水润泽杭州城里的千家万户开始,西湖就成为杭州城不可分割的一个部分。同时,杭州城的不断发展兴盛也有效地阻遏了它的沼泽化过程使之继续存在。西湖,从一个大海湾,到一个泻湖,在不断地淤积疏浚过程中,最终成为一个风景湖泊。它的形成与发展过程,就是一部保护与治理的历史。这其中贯穿了中国传统山水文化的精神和理念,体现了西湖历史文化的延续性。     

明代运河“水脊”的形成及其意义

明后期以降的史籍普遍认为南旺自元代起一直是会通河沿线的制高点“水脊”,元明会通河成败的关键就在于是否选择了南旺“水脊”作为分水口,这种观点不正确。南旺湖原本是梁山泊最后的余绪,地势低洼,明初宋礼引汶水到南旺济运后开始淤积,成化年间确定南旺分水核心地位后,挑出的泥沙堆积在运河和小汶河两岸形成土山地貌,构成明后期以降人们眼中的“水脊”意象。即南旺“水脊”形成于明代中叶,是汶水泥沙淤积和人工挑浚堆积的结果。据此,需重新审视元明会通河成败的原因,讨论明代中叶南旺“水脊”的形成对会通河水源从暴虐黄河水到安稳汶河水的转变的意义及其对明中叶以降治黄原则的深远影响。     

20世纪七八十年代引滦工程决策历程

水资源短缺一直制约着京津唐地区经济和社会的发展。20世纪70年代,因缺水引发的经济、社会问题逐渐凸显,促使中央和地方政府开始考虑实施跨流域调水工程。引滦工程作为北方最大的跨流域调水工程,其决策经历了曲折的过程。1958年,北京和唐山曾分别提出引滦河水的设想,唐山还实施了引滦入还和引还入陡工程。1972年,海河流域大旱促使中央做出加快实施引滦工程的决定,但由于地质情况复杂等原因,引滦工程设计方案被反复修改。1981年,天津提出了单独引滦济津路线并得到了中央的支持。引滦工程对缓解京津唐用水紧张发挥了重要作用,天津是引滦工程受益最大的地区。     

Ecohydrology and Environmental Change to Lake Albacutya and Wyperfeld Park in North‐Western Victoria,Australia

Lake Albacutya is a well‐known intermittent lake in north‐western Victoria. The lake is near the termination of the Wimmera River. From time‐to‐time the lake fills and flow passes down Outlet Creek into Wyperfeld National Park. The wetlands associated with the lake have a high biodiversity value and are named in international treaties. This paper examines the hydrologic factors associated with lake filling and flow into Wyperfeld. The lake has filled approximately six times since 1880 and has partially filled on other occasions. Examination of rainfall data from 1875 at Horsham gave no indication of long term rainfall decline, and showed that rainfall at Horsham can be viewed as representative of rainfall in the Wimmera River catchment. However a double‐mass analysis showed that the relationship between the Wimmera River flow and rainfall has varied from 1890 to the present. Examination of data associated with six fillings of Lake Albacutya suggested that filling is a two‐year event requiring at least 550 GL of flow passing Horsham over the two years immediately associated with the flood. A simple model based on rainfall and this threshold reproduced observed characteristics of the data reasonably well. This suggested that the flooding frequency of Lake Albacutya has dropped from about one in 25 years in the natural state to a substantially lower frequency under current river conditions. The results also suggested that because of changes in the Wimmera River the last filling and flood into Wyperfeld in 1976 was far smaller than it would otherwise have been. This is consistent with field mapping of the flood in relation to River Red Gum (Eucalyptus camaldulensis Dehnh.) stands. Analysis of the health of these stands showed major dieback with the severity of this being roughly proportional to the distance from the 1976 flood boundaries. An examination of values associated with the lake and adjoining Wyperfeld National Park suggested that biodiversity and economic values are and will be compromised by the reduction in flooding. In particular, an internationally‐known provenance of Red Gum is at risk, and bird‐breeding opportunities have diminished.     

论湖泊的自然衰亡与可持续开发利用——以杭州西湖古今开发为例

从地理学角度看,湖泊都有自然沼泽化的趋势。人类活动可以加剧或者减缓这种趋势。杭州西湖就是由于人们古往今来的长期良性开发,才得以保存至今而且成为著名风景胜地的。在阐明这一原理的基础上,本文分析评价了近20余年来人们对此湖的开发行为,结论是:良性和非良性开发都在持续。这一结论对国内许多同类湖泊而言具有一定普遍性或代表性。     

Holocene lakes and prehistoric settlements of the Western Faiyum,Egypt

Holocene lake stages in the Faiyum depression commenced with a high lake stand during the 10th millennium bp, followed by an early Holocene lake from 8500 to 7000 bp. A pronounced recession and the development of a palaeosol preceded another rise to a mid-Holocene, high lake level from 6500 to 5100 bp. A major drop in level coincided with the late Neolithic and Early Dynastic. The Moeris lake witnessed by Herodotus is also documented. The drop in lake level during early Ptolemaic times marked the end of the freshwater lake and was apparently, in part, a result of declining Nile floods. Terminal Palaeolithic sites are associated with the early Holocene lake and Neolithic sites with the mid-Holocene phase. Prehistoric settlements were placed near lake-margin marshes and ponds. The richness of the lake margin in aquatic resources and its susceptibility to short- and long-term fluctuations influenced both subsistence and settlements, and is believed to have encouraged a para-agricultural economy.     

历史时期大清河南系的变迁研究——兼谈与白洋淀湖群的演变关系

海河水系以"清"为名的大清河其实只是相对于位居其南、其北著名浊流滹沱河与永定河而言的"清"河。历史时期,随着上游水土流失的日益加剧,大清河南系各河含沙量不断增高,干流段决徙逐渐频繁。本文利用历史文献,对先秦以来在自然与人类活动共同影响下的大清河南系的变迁进行了探讨,揭示和总结了两千余年来水系格局变动的基本过程及主要特点。大清河南系又是白洋淀湖群地表径流补给最大的水源,上述研究结论还将是理解和分析这一著名湖群演变不可忽视的重要基础。     

Two Artificial Anchorages off the Northern Shore of the Dead Sea: a specific feature of an ancient maritime cultural landscape

A recently discovered artificial stone mound on the northern shore of the Dead Sea is a maritime feature exposed by the drying of the lake. Lake‐level fluctuations, a loose silt bottom, lack of natural anchorages, and onshore prevailing winds, prevented the long‐term planning, construction and maintenance of shore‐based harbour installations in this area. This and a similar mound nearby, Rujum el Bahr, are interpreted as structures once used for open‐water mooring, providing a firm anchor‐hold over a range of lake levels and wind directions. As such, they enabled the use of this economically and strategically important part of the lake by maritime traffic.     

明清时期漳河平原段的河道变迁及其与“引漳济运”的关系

漳河是海河水系重要的支流。历史时期,在自然环境与人为因素的共同作用下,漳河平原段具有易淤、易决与易徙等特征。本文以明清(1368-1911年)为研究时段,对漳河的变迁过程进行了尽可能具体、详细的复原和定位。并在此基础上,探讨了漳河变迁的特点与规律。     

洞庭湖变迁的历史过程再探讨

关于洞庭湖的历史变迁过程问题,学术界一直没有取得共识。本文认为,今洞庭湖地区在先秦两汉时期尚处于河网沼泽平原阶段,没有形成大型湖泊;进入魏晋南朝隋唐时期,今洞庭湖地区的湖泊水体得到快速扩展;唐后期至清前期,今洞庭湖地区的湖泊水体面积处于全盛阶段;自清中期以来,随着长江来沙量的日益增加,湖泊进入明显的萎缩阶段。历史时期洞庭湖的形成与变迁主要取决于洞庭湖区的沉降速度和长江干流的来沙量。     

DAMMING JAMES BAY: I. POTENTIAL IMPACTS ON COASTAL CLIMATE AND THE WATER BALANCE

The proposed grand Canal project calls for the damming of James Bay and the diversion of its water southward. This first part of a two-part study models some potential impacts on the climate, water balance, and growth patterns in the James Bay coastal zone. Use is made of a linear relationship of Bowen ratio and temperature, developed from studies of coastal wetlands in southern and northwestern James Bay and central Hudson Bay. It is hypothesized that changing James Bay into a fresh-water lake and disrupting its coastal currents would result in a delayed Bay ice melt of unknown length in the spring. Allowing a delay to vary between 0 and 30 days results in the prediction of lesser evaporation and greater water surplus. These differences in magnitude increase with the length of delayed melt, but in all cases are most strongly evident during the peak of the growing season. Colder and wetter conditions would have a strong ecological impact on all coastal areas of western and southern James Bay. In the northwest this could change the species composition of coastal flora, cause forests to retreat from the coast, and result in the growth of permafrost there.     

明清时期福州西湖水环境变迁及其治理研究

明清时期,福州西湖水环境总体趋劣。明代西湖水源较为充足,水质状况良好;万历以降,受民间占垦等社会因素影响,湖域面积缩减,水质日渐趋下;清代中后期,福州城内水道淤浅,江潮渐绝,西湖水源趋向单一。明清时期西湖水环境的变动,除了受区域气候干湿变化、山地森林水土保持以及湖泊含沙量的影响之外,还与人为的水地之争密切相关。由于人地关系紧张,加之水资源权属不清、新垦湖田税赋征收模糊等,获取湖利的必然性刺激了民间占湖为地的行为。地方官府也曾采取如修闸筑坝护堤、追返侵地还湖、清理粪秽淤泥等治理措施,并取得阶段性成效,但受区域人口、土地资源与生存环境等社会经济因素的影响,西湖历经多次治理仍积弊难除。     

云梦问题的新认识

自唐以来,学者虽然对先秦楚地云梦的位置、范围颇有争议,但一直都以"云梦"作为湖泊水体专名或游猎区专名。由于先秦迄汉晋时代在江汉—洞庭平原长江南北、峡江地区、黄淮平原淮河以北分布有七处以上的云梦,而汉代的"云梦官"不止一处,楚国(地)人也有"薮曰云"、"梦,泽中"、"梦,草中"之类的解释,因此早期"云梦"应不是专名,而是古夏(汉)语楚地方言对具有游赏意义的水体不大但植被繁茂之区的通称,其本来含义即为草泽或泽草。云梦分布的广泛性和云梦含义的揭破,不但可以较好解决学界关于云梦与云梦泽问题的长期争论,也使我们能够正确认识历史早期江汉—洞庭平原、华北平原、峡江等地的自然环境面貌。     

元代的吴淞江治理及干流“改道”问题

曾为太湖的主要泄水入海通道的今黄浦江支流吴淞江 ,当有元一代 ,曾经进行过规模相当、持续不断的“治理”。通过对相关资料的重新考察 ,得出以下结论 :一、由于时人的“肆意妄为”,入元以后的十数年间 ,原本“安流”的吴淞江水系遭到了严重的破坏 ,从而开始了难以“恢复”的不可逆转。二、至元末的淀山湖工程、大德末的吴淞江工程以及泰定、至顺、至正中的工程 ,都不是“有效”的水利工程 ,究其原因 ,一是没有从整体的利害关系考虑 ,二是有违当时已经形成的“自然”态势 ,那就是太湖水流宣氵曳日益向南的“必然”演化。三、关于南宋吴淞江的干流 ,并不如许多研究者所言即明代的“虬江”、今天的西虬江。准确的表述应是 :当时的吴淞江河床包含今吴淞江南岸到虬江北岸间的整个区域。“虬江”亦是“旧江”,不过是由于河床垫高、水流分岔后的一股北去水道的遗迹而已     

Late Quaternary ostracods from Lake George,New South Wales

Fossil ostracods from the uppermost 3m of core LG4 from Lake George all have modern living representatives. This part of the core is thought to represent deposition during the last 60,000 years (see Singh et al., 1981b) and the lake hisotry is traced from a knowledge of the ostracod ecology.

The following distinct phases, and their respective timing, are postulated for Lake George (the timing of events should be considered with caution as few ¹⁴C dates are available): water fresh and lake full for the periods of 10,200 – 12,000 yBP and 19,100 – 20,700 yBP, water fresh, ephemeral at times, for the periods of 3,200–4,000 yBP, 7,000 yBP, 7,500 yBP, 8,500–10,200 yBP, 12,000–13,500 yBP, 20,700–23,500 yBP, 23,800–27,600 yBP and at some stage between 27,000 and 60,000 yBP; ephemeral saline water for a few short episodes between 3,200 and 4,000 yBP and for the periods of 15,600–17,400 yBP and 23,800–27,600 yBP; lake definitely dry between 17,400 and 19,100 yBP.

Data obtained from the ostracods correlate reasonably well with those of lake level fluctuations based on the study of ancient shorelines by Coventry (1976) and others based on facies analyses and the record of plant microfossils by Singh et al. (1981b).     

Environmental response to land use at Lake Curlip,East Gippsland,Victoria

A palaeoecological approach was undertaken to investigate the last 400 years of change in vegetation, fire, nutrient mobility, lake productivity and erosion associated with Aboriginal and European land-use practices in a forested environment in eastern Victoria. Melaleuca ericifolia scrub, although present prior to European settlement, has expanded around Lake Curlip in the last 200 years, primarily due to the action of fire on a forest already weakened by drought. A fern understorey has declined in extent and a more open aspect has developed in the forest. Fire has been a major component of vegetation dynamics in the historical period. Erosion rates were comparatively low and associated with fire during prehistoric times, but after European settlement its increase is more closely related to land clearance and flooding than fire. The response of vegetation to both anthropogenic and natural influences changed during the historical period. Although fire is an integral part of vegetation change, it is not an over-riding effect at Lake Curlip. Drain construction in the swamp has reduced the impact that any accumulation of pasture improvement chemicals may have had on eutrophication of the lake.     

幻景中的沉城记忆:清代黄淮运交汇区的湖市蜃楼

沉城之灾是水环境变迁引发的极端事件,湖市蜃楼以祥瑞的幻景方式重复着沉城的灾难记忆。黄淮运交汇区湖泊水系众多、河工频繁,为明清时期蓄清、刷黄、济运的水利核心区。尤其清代以后,治河无须兼顾护陵,湖泊环境的剧烈变迁引发洪泽镇、泗州城等沉入水底,给当地环境社会带来深远影响。史籍中有关湖市蜃楼的记载多见于湖面急剧扩大的清代,在洪泽湖、高宝诸湖上均有发生;蜃景发生时多被与时间空间上最近或影响最大的沉城事件联系起来。沉城再现的湖市蜃楼固然不可信,但幻景中包含了百姓的灾难记忆,提醒人们历史需被记忆,灾难不应遗忘。