Hydrological impacts of flow regulation associated with the Upper Nepean water supply scheme,NSW

The upper Nepean River has been progressively regulated for water supply to Sydney and Wollongong since 1886 by the Upper Nepean Water Supply Scheme which consists of four large dams, two small dams and two diversion weirs. Secular rainfall changes produced periods of high rainfall and large floods (flood‐dominated regimes) between 1857 and 1900 and 1947 and the present, and an intervening period (1901–46) of low rainfall and small floods (drought‐dominated regime). Upstream impoundment and flow regulation significantly reduced flood magnitudes for most return periods during both types of flood regimes. The probability distribution of mean daily flows was also changed significantly by flow regulation such that during the drought‐dominated regime, the high and low frequency flows were reduced substantially but the moderate frequency flows were increased due to dam releases; the change from a regulated drought‐dominated regime to a regulated flood‐ dominated regime resulted in a substantial increase in discharge for most durations; and increased water diversions to Wollongong during the current flood‐dominated regime produced a marked downward shift in the whole flow duration curve. Nepean Dam reduced downstream suspended sediment yields by two orders of magnitude because it traps in excess of 99 per cent of the inflowing suspended sediment load. Streamflow releases are urgently required from the two diversion weirs to improve downstream water quality and to ensure the viability of the resident ‘potentially threatened’ eastern Macquarie perch (Macquaria nov. sp.).     

Improved mappint of the Lake Agassiz Herman strandline by integrating geological and soil maps

Several discontinuous, segmented strandlines that mark the former shores of Lake Agassiz can be found in eastern North Dakota. These strandlines are difficult to map and correlate because of their segmented nature. Better mapping would benefit researchers working on a number of problems involving Lake Agassiz including dating the strandlines, reconstructing the lake's history, and calculation of asthenosphere viscosity beneath the Lake Agassiz basin. Elongated soil delineations representing beach-indicative soils with a north-northwest trend and extending from currently mapped areas of the Herman strandline were identified on Grand Forks County soil maps. This information was combined with the geologic map of Grand Forks County in an attempt to better define the location of the Herman strandline in the southern part of the county. This approach worked well, and it is recommended that similar studies be attempted on other Lake Agassiz strandlines in North Dakota and the surrounding area.     

Quaternary soil chronosequences on terraces of the Susquehanna river, Pennsylvania

Susquehanna River terraces are used to establish time lines along a 150 km reach of the river, from the Lower Piedmont to the edge of the Appalachian Plateau. This is achieved by generating soil chronosequences at two locations — Marietta, PA, in the Lower Piedmont, and Muncy, PA, near the glacial border on the boundary between the Valley and Ridge province and the Appalachian Plateau. These sites preserve the most complete record of fluvial incision on the Susquehanna River with flights of seven Quaternary terraces ranging in elevation from 3 m to 51 m above the modern river.Soil characteristics used to develop the soil chronosequences include complexity of horizonization, thickness of B horizon, clay content of B horizon, soil color, CBD extractable Fe, Al, and Mn, total extractable Fe, and clay mineralogy. Terrace age constraints are based on soil development, correlation to regional glacial stratigraphy, correlation to dated fluvial and glaciofluvial deposits, and by paleomagnetic analysis of sediments. Terrace ages at the Muncy site range from modern (< 150 ybp) to Middle Middle through Early Middle Pleistocene (∼ 300 ka to ∼ 770 ka). Marietta has terrace ages ranging from modern (< 150 ybp) to Early Pleistocene through Late Pliocene (∼ 770 ka to ∼ 2400 ka).     

Sequences and genesis of the Yellow River terraces from Sanmen Gorge to Kouma

Based on field landscape investigations, thermoluminescence (TL), magnetostratigraphy and loess-paleosol sequence, we found that there are at least four Yellow River terraces, whose ages are 0.86 Ma, 0.62 Ma, 0.13 Ma and 0.05 Ma, in Yuxi Fault-Uplift (from Sanmen Gorge to Mengjin) and at least three Yellow River terraces, whose ages are 1.24 Ma, 0.25 Ma and 0.05 Ma, in Huabei Fault Depression (from Mengjin to Kouma). All the terraces have a similar structure that several meters of paleosols directly develop on the top of fluvial silt. It shows that the Yellow River incised and consequently abandoned floodplain converted to terrace during the interglacial period. Therefore, there may be a link between the formation of terraces and glacial-interglacial climatic cycles. However, the differences in the Yellow River terrace sequences and ages between Yuxi Fault-Uplift and Huabei Fault Depression indicate that the surface uplift should play an important role in the formation of these terraces.     

黄河三门峡至扣马段的阶地序列及成因

Based on field landscape investigations, thermoluminescence (TL), magnetostratigraphy and loess-paleosol sequence, we found that there are at least four Yellow River terraces, whose ages are 0.86 Ma, 0.62 Ma, 0.13 Ma and 0.05 Ma, in Yuxi Fault-Uplift (from Sanmen Gorge to Mengjin) and at least three Yellow River terraces, whose ages are 1.24 Ma, 0.25 Ma and 0.05 Ma, in Huabei Fault Depression (from Mengjin to Kouma). All the terraces have a similar structure that several meters of paleosols directly develop on the top of fluvial silt. It shows that the Yellow River incised and consequently abandoned floodplain converted to terrace during the interglacial period. Therefore, there may be a link between the formation of terraces and glacial-interglacial climatic cycles. However, the differences in the Yellow River terrace sequences and ages between Yuxi Fault-Uplift and Huabei Fault Depression indicate that the surface uplift should play an important role in the formation of these terraces. Foundation: Science and Technology Planning Project of Yunnan Province, No.2007D199M; National Natural Science Foundation of China, No.40462002; No.40161002 Author: Su Huai (1977–), Ph.D, specialized in geomorphology and Quaternary geology.     

Runoff and soil erosion on cultivated rainfed terraces in the Middle Hills of Nepal

The paper presents runoff and soil erosion measurements from plots on outward-sloping rainfed agricultural terraces in the Likhu Khola drainage basin, Middle Hills, Nepal, for the pre-monsoon and monsoon periods of 1992 and 1993. Runoff coefficients ranged from 5% to over 50%, depending on the nature of the rainfall event and the characteristics of the terrace. Total rainfall amount provided the highest level of explanation for the variation in runoff. Soil losses ranged from 2.7 to 8.2 t ha^–1 for 1993 and up to 12.9 t ha^–1 for 1992. The higher losses were associated with red, finer-grained soils. The majority of these rates are lower than the rates of soil loss that have been commonly perceived for the Middle Hills of the Himalaya. However, they are broadly similar to rates obtained from the few other studies that have examined runoff and erosion under traditional rainfed cultivation. The results suggest that a re-evaluation of the degree of land degradation in such areas may be necessary. Relationships between soil loss and rainfall characteristics were highly variable but were improved considerably when vegetation cover was included. This indicates that the maintenance of some form of ground cover is advisable if runoff and erosion are to be minimized.     

贵州高原北部河流阶地发育与喀斯特地貌演化

贵州高原北部发育平缓丘丛和深切峰丛2种喀斯特地貌组合,保存于喀斯特山间盆地的河流阶地对区域地貌演化具有指示意义.本文根据阶地发育特征和光释光(OSL)测年,分析阶地形成的时代和动力,结合区域地质背景,探讨构造抬升和河流侵蚀对黔北喀斯特地貌演化的驱动作用.结果显示,绥阳盆地T1阶地时代18.8?8.2 ka,T2时代14...     

土壤可蚀性研究述评

土壤可蚀性是土壤对侵蚀作用的敏感性。对土壤可蚀性的研究是认识土壤侵蚀机理的一个重要环节。土壤可蚀性可以通过测定土壤的理化性质、水冲、模拟降雨、小区和风洞试验测定,可以使用土壤侵蚀模型与诺谟图计算土壤可蚀性。研究中产生了许多可蚀性指数和计算公式。土壤可蚀性是一个相对的概念,它受空间变化、土壤性质的时间动态变化和人类活动等因素的影响。在土壤可蚀性的研究中存在着一些不足,具体表现为:农田土壤是土壤可蚀性研究的主要对象,区域之间的土壤可蚀性缺乏对比,因此加强对土壤可蚀性机理、实验与风水复合侵蚀作用下土壤可蚀性的研究有着十分重要的意义。     

鄂尔多斯高原周缘黄河阶地的形成与青藏高原隆升

构造运动和和气候变化是河流阶地形成的两个重要因素。学术界对于构造运动与气候变化中哪个因素是河流阶地形成的控制因素尚未形成一致观点。本文选择位于鄂尔多斯高原周缘的河流阶地,综述了前人在兰州段、中卫段和晋陕峡谷段3个河段的黄河阶地上的研究成果,结合2万年以来的古洪水记录与古地震活动等证据,对比了河流阶地形成、气候变化以及青藏高原的幕式隆升的时间。对比结果显示,鄂尔多斯高原周缘多级河流阶地的形成时间与青藏高原阶段性隆升的时间比较一致,而与气候冰期—间冰期变化之间没有明显规律,这一结果支持构造运动是鄂尔多斯高原周缘的河流阶地形成的控制因素。     

A rockfall avalanche in a sandstone landscape,Nattai North,NSW

Rockfall avalanches are commonly associated with the alpine regions of Europe, South America and north‐western Canada, but modern examples have only been reported very recently in Australia (Pells et al. 1987). The Nattai North rockfall avalanche is located on the Burragorang Walls escarpment in the sandstone landscape of the Sydney Basin. The volume of rock involved in the failure had sufficient magnitude to enable the resulting mass of debris to flow in the manner of a semiviscous fluid. The conventional models of rockslope evolution, involving undercutting followed by blockfalls, do not apply at this site. Indeed these models do not apply to most of the large‐scale rock collapses in the Sydney Basin. All such rockfalls have occurred in the vicinity of underground coal mines. Coal mining has affected the stability of nearby escarpments by altering stress distributions within the rock mass. The subsequent failures are typically larger and of a different form than those occurring naturally.     

郧县盆地风成黄土—古土壤与汉江Ⅰ级阶地形成年龄研究

在对汉江上游河谷进行野外考察的基础上,就郧县盆地汉江Ⅰ级阶地及其风成黄土-古土壤覆盖层沉积学和理化性质进行了研究,并且采用OSL方法进行了测年断代.获得了26个OSL年龄数据,证实厚层风成黄土L1底部的年龄在25 ka BP,而剖面底部风成黄土-冲积砂层交互层(T1-al2)年龄范围在55-25 ka BP之间.地层年龄说明Ⅰ级阶地上黄土的堆积过程基本连续,汉江Ⅰ级阶地的发展经历了早期新构造抬升与河流下切阶段(55-25 ka BP)和晚期阶地面稳定接受沉积(25-0 ka BP)两个阶段.距今55 ka BP前后,新构造运动抬升和汉江下切作用加剧,河漫滩相沉积层开始脱离水面并接受风尘堆积物.这个过程持续到距今约25 ka BP,期间河水不时地淹没阶地面,从而形成了风成黄土-冲积砂交互的沉积学特征.距今约25 ka BP以来,河水不再淹没阶地,汉江Ⅰ级阶地最终形成,阶地面开始接受连续的风尘堆积.在汉江下切作用加剧的同时,全球性末次冰期的发展也逐步进入冰盛期,风尘活动强烈,在阶地表面堆积形成了厚层黄土.汉江Ⅰ级阶地形成以来,气候的变化使黄土覆盖层受到不同程度的风化成壤改造,形成了黄土-古土壤地层,其地层序列从下向上依次为:河流相砂卵石层(T1-al1)→黄土-冲积砂互层(T1-al2)→马兰黄土(L1)→过渡黄土(L1)→古土壤(S0)→近代黄土(L0)→表土(MS).这个层序记录汉江上游流域自从25 ka BP以来的气候变化经历末次冰期后东南季风逐渐加强、中全新世季风强盛、晚全新世季风衰退和气候变干的演变模式.     

Morphometric and geological conditions for sediment accumulation in the Udava River,Outer Carpathians,Slovakia

The accumulation of sediment in river channels is a phenomenon that is not only influenced by the channel morphology, but also by the physical and geographical characteristics and the endogenous and exogenous processes taking place in the catchment. This paper presents an analysis of the impact the changes in lithological conditions have on the morphological and morphometric parameters of the Udava River channel and their relation to the channel accumulation forms representative of the river’s longitudinal profile as well as of its planform. Results document when accumulation forms occur and what is their spatial distribution within the longitudinal and cross-sectional river profiles. More resistant structures created sections with a lower degree of sedimentation, while in depression segments the degree of sedimentation was higher. With the increase in longitudinal slope, the impact of channel width on the average channel bar size increased. Also a difference in the accumulation was observed between the left and right bank which could be possibly explained by the impact of Coriolis force.     

中国水土保持研究回顾

The preservation and sustainable development of soil and water resources is one of the basic principles for the development of China. Throughout the course of history, all the social improvement and economic development are deeply concerned with soil loss and ecological environmental protection. It is now a common sense that soil and water conservation is the safety insurance for national ecology and its development. For the past long period of time, soil and water loss has been recognized as “the No. 1 killer“ to the ecological environment. The nation is on the stage of the critical conditions for its development. China has massive mountain and upland area with complicated geological conditions and accelerated human destruction and serious soil and water loss.Based on rich historical documents, renovating experience and detailed analysis of the data collected in field experiments and field surveys for soil and water conservation, this paper aims to review the general characteristics of soil and water loss, to explore the relationship between soil and water conservation and sustainable economic development, and to provide relevant strategies for soil and water conservation in China.     

A review of soil and water conservation in China

The preservation and sustainable development of soil and water resources is one of the basic principles for the development of China. Throughout the course of history, all the social improvement and economic development are deeply concerned with soil loss and ecological environmental protection. It is now a common sense that soil and water conservation is the safety insurance for national ecology and its development. For the past long period of time, soil and water loss has been recognized as "the No.1 killer" to the ecological environment. The nation is on the stage of the critical conditions for its development. China has massive mountain and upland area with complicated geological conditions and accelerated human destruction and serious soil and water loss. Based on rich historical documents, renovating experience and detailed analysis of the data collected in field experiments and field surveys for soil and water conservation, this paper aims to review the general characteristics of soil and water loss, to explore the relationship between soil and water conservation and sustainable economic development, and to provide relevant strategies for soil and water conservation in China.     

金沙江金江街段河流阶地年代及对河谷水系演化历史的启示

100多年来,关于金沙江独特水系格局的形成历史一直是地学界争论的重要话题之一。多数学者认为,现代金沙江水系是古长江袭夺古红河上游发展过来的。红河海底扇5.5 Ma泥沙供给中断被认为与这一袭夺事件有关。然而,长期以来人们一直没有找到与这一时代相匹配的地貌证据。最近在金沙江金江街段找到了多达8级的河流阶地序列,ESR测年结果显示这些阶地的形成年代为1.07 Ma、0.70 Ma、0.65 Ma、0.51 Ma、0.47 Ma、0.44 Ma、0.30 Ma和0.18 Ma,结合GPS高程测量数据,推算最近1.0 Ma以来的河谷平均下切速率为147 mm/ka。以填充河谷地形为主要手段的古地形恢复结果（基于DEM数据）显示,古长江袭夺古红河上游形成现代金沙江水系发生在这一区域内海拔2000 m左右的古地形面解体之后,依照河谷平均下切速率外推,古地形面解体时代为5.5 Ma,即现代金沙江水系形成于5.5 Ma之后。我们的研究结果与红河海底扇的资料形成一个相互呼应的证据链,为重建现代金沙江水系格局形成历史提供重要依据。     

A review on the eco-geography of soil fauna in China

This review summarizes main research findings in soil fauna eco-geography in China in the past 30 years. The subject areas and main results were overviewed including biodiversity and eco-geological distribution of soil fauna communities. Studies of ecological distributions of soil fauna and dynamic ranges in space from tropical, subtropical to temperate regions, and in categories from forest, grassland, desert, wetland, farmland to urban ecosystems, the responses and indications of soil fauna to soil environments. Effects of intensive disturbance such as fire, grazing, farming, fertilization on soil fauna include sensitive (e.g. nematode) and rare groups and community indexes. The functions of soil fauna were discussed including environmental construction, environmental purification, litter decomposition and elements cycling. Interactions between soil fauna and other biota in soil ecosystems and linking between aboveground and belowground diversity and the effects of global change on soil fauna community in China were also included. Finally, the authors pointed out common interests in soil fauna eco-geographical studies, which include application of molecule biology into soil fauna taxa; function and mechanism of soil fauna community diversity; interaction between aboveground and belowground ecosystems; effects of disturbance, pollution, biological invasion, and global change on soil fauna community and function. The review is to provide a scientific basis for promoting soil fauna eco-geographical studies in China.     

中国土壤动物生态地理研究进展(英文)

This review summarizes main research findings in soil fauna eco-geography in China in the past 30 years.The subject areas and main results were overviewed including biodiversity and eco-geological distribution of soil fauna communities.Studies of ecological distributions of soil fauna and dynamic ranges in space from tropical,subtropical to temperate regions,and in categories from forest,grassland,desert,wetland,farmland to urban ecosystems,the responses and indications of soil fauna to soil environments.Ef...     

Land management,geological and soil effects on streamwater chemistry in upland mid-Wales

Streamwater chemical data are presented to show that the difference in chemistry between a number of first-order streams can be interpreted in terms of bedrock, soil and land management influences. A change in lithology within a geochemically uniform bedrock had little effect on streamwater chemistry. Small-scale calcite mineralization, however, coincided with significant increases in pH and the concentrations of calcium and bicarbonate; other solutes were generally unaffected. Land improvement resulted in increased concentrations of several solutes; some reflecting addition as fertilizer and others the effects of cultivation. Differences in the amount of peat within the catchments and hence the proportion of water derived from peat also influenced the pH and the concentrations of calcium and bicarbonate present in the streamwater.     

A review of mortality maps included in the annual reports on vital statistics for Ireland, 1864-1998

Since 1864, some 135 reports have been produced examining marriages, birth and deaths for Ireland. The reports produced during the period prior to World War I are notable for the maps and charts that are included and the level of detail provided. Recent reports have failed to include mortality maps, while those produced since 1950 generally show a declining level of detail.     

黄河冲积扇发育研究述评

黄河冲积扇是第四纪以来多期沉积建造的冲积扇复合体,它既是来自黄土高原的泥沙强烈堆积的地貌单元,又是历代河流决口改道的地区,也是华夏文明的发源地。在回顾了黄河冲积扇发育的研究历史的基础上,详细介绍了黄河冲积扇的形成时代、地貌类型与沉积速率,形成过程与特点等方向的研究进展,系统地论述了河道变迁、地质构造、气候变化以及人类活动等因素对黄河冲积扇形成的影响作用。并指出目前黄河冲积扇的发育研究中还存在着研究深度不够和时空的广度不完整等问题。史前黄河冲积扇的发育研究将成为今后研究中的难点。