中国地下水资源演变趋势及影响因素分析

中国地下水资源发生了显著变化,全面摸清地下水资源演变趋势及其影响因素是治理和管理地下水资源的基础。基于全国水资源调查评价、中国水资源公报等资料,对中国60余年来地下水资源的演变规律与影响因素进行了系统分析。结果表明：全国地下水资源量总体稳定,但区域演变趋势差异明显,海河区、辽河区、黄河区呈明显衰减态势;地下水补给结构发生重大变化,由自然补给演变为自然与人工补给并存的模式;地下水排泄结构发生巨大变异,由天然排泄逐渐演变为以人工排泄为主。海河区、松花江区、黄河区、西北诸河区等区域地下水补给排泄关系严重失衡,超采问题突出;降水变化、下垫面条件改变、人类活动干扰是地下水资源变化的主要原因。     

中国地下水资源演变趋势及影响因素分析

中国地下水资源发生了显著变化,全面摸清地下水资源演变趋势及其影响因素是治理和管理地下水资源的基础。基于全国水资源调查评价、中国水资源公报等资料,对中国60余年来地下水资源的演变规律与影响因素进行了系统分析。结果表明:全国地下水资源量总体稳定,但区域演变趋势差异明显,海河区、辽河区、黄河区呈明显衰减态势;地下水补给结构发生重大变化,由自然补给演变为自然与人工补给并存的模式;地下水排泄结构发生巨大变异,由天然排泄逐渐演变为以人工排泄为主。海河区、松花江区、黄河区、西北诸河区等区域地下水补给排泄关系严重失衡,超采问题突出;降水变化、下垫面条件改变、人类活动干扰是地下水资源变化的主要原因。     

北京市重要地质遗迹资源保护规划探讨

北京素有中国地质工作摇篮之称,在几亿年的地质演变长河中,受不同时期的地质作用,形成了形态多样、类型独特的地质奇观。众所周知,地质遗迹是不可再生资源,合理的规划、利用和保护能为地质科研教学、旅游资源可持续发展做出贡献。为遏制地质遗迹破坏的趋势,建议制定北京市地质遗迹保护规划,并分期实施,近期对区内已遭严重破坏的地质遗迹进行抢救性保护,初步探讨北京地质遗迹保护方案。     

环境演变区域分异的表现形式

环境演变区域分异的表现形式方修琦（北京师范大学资源与环境科学系，北京，１００８７５）随着对全球变化区域响应问题的日益重视，环境演变区域分异的研究已成为热点问题之一。所谓环境演变的区域分异有两方面的含义：一是全球变化的区域表现形式各不相同，二是区域分异...     

咸海流域水文水资源演变与咸海生态危机出路分析

中亚的咸海问题已成为全球性的生态和社会问题,研究咸海流域水文水资源、经济社会发展演变与气候变化,对深入理解中亚地区咸海危机形成机理、未来发展趋势、探讨咸海生态危机出路具有重要意义,对类似区域跨界河流和我国西北干旱区水资源开发利用具有重要借鉴意义. 介绍了中亚五国咸海流域的水资源及其开发利用情况,重点分析了中亚五国咸海流域农业灌溉的发展演变、近80a来咸海流域气候变化趋势与主要河流水文演变情势及咸海水文特征演变. 结果表明,咸海生态危机完全是由人类自导并日益严重的水资源-生态-环境与社会危机,短期内难以遏制,长期来看也无法逆转. 结合咸海危机生态环境效应,讨论了3个跨流域调水方案拯救咸海的利弊与前景,探讨了立足于流域本身拯救咸海的综合治理措施. 最后,提出了咸海危机经验教训对我国内陆河水资源开发利用的若干启示.     

洛阳市地下水位下降及防降对策研究

因大量开采地下水而引起地下水位持续下降,形成开采降落漏斗。诱发地面沉降,地下水资源枯竭,造成地质灾害发生。本文在论述了洛阳市地下水动态变化特征及演变趋势的基础上,提出了防治地下水下降的对策。供有关部门参考。     

中国农作物绿水占用指数估算及时空差异分析

从农作物生长消耗的绿水量入手,构造了农作物绿水占用指数,选取中国31个省区作为研究对象,通过对农作物绿水占用指数的计算,揭示中国各省区农业生态系统对绿水资源占用情况的空间分布特征,发现农作物绿水占用指数高的地区以黄淮海平原为核心集中分布,低的地区则主要分布在中国的西部。利用空间自相关分析方法,对中国1997～2007年农作物绿水占用指数的总体空间区域差异及时间演变趋势进行研究,结果显示,中国农作物绿水占用指数空间上存在着显著的集聚现象,但该现象逐年呈减弱趋势。结合局部自相关分析,对中国31个省区11年间的农作物绿水占用指数区域分异的时空演变规律进行探索,并对演变原因做出解释。     

黑河中游水资源开发利用与管理的历史演变

从历史的角度探讨了黑河中游水资源开发利用与管理的演变过程.辨别了历史上不同时期黑河中游水资源管理的状况,分析了兴衰的原由,探讨了水资源管理演变的趋势、特征以及存在的问题,总结了历史上可资借鉴的经验,说明资源管理问题与社会问题和其他问题相互之间是不断转化的,对策措施集合也是不断调整的.简要论述了部分历史经验在建立水资源利...     

世界资源格局与展望

本文阐释了人均能源消费、人均矿产资源消费与人均GDP“S”形规律的内涵, 指出发达国家(OECD)能源与重要矿产资源消费已经或正在进入零增长期, 资源需求将趋稳或呈缓慢下降趋势, 发展中国家已经成为资源消费主体, 全球能源与矿产资源需求重心正在向亚洲转移; 以石油为例, 阐述了国际资源市场体系的演变及其脆弱性, 强调发展中国家经济发展的资源成本将呈不断上升态势, 低碳经济将推动全球新能源及相关产业快速发展, 提出了发展中国家应对国际资源格局变化的相关对策和建议。     

雅鲁藏布江径流演变规律及其驱动因子分析

本文以雅鲁藏布江为研究对象，结合Mann—Kendall非参数检验方法，分析了流域1956—2000年的年径流演变规律及其驱动因子。结果表明，流域径流总体上呈减少的趋势，演变过程中表现出明显的阶段性和突变性。相关分析进一步揭示了降雨是河川径流演变的主要驱动因子，气候变化也在一定程度上控制着径流演变的趋势。     

Internal architecture and evolution of bioclastic beach ridges in a megatidal chenier plain: Field data and wave flume experiment

Beach ridges in macrotidal environments experience strong multi‐annual to multi‐decennial fluctuations of tidal inundation. The duration of tide flooding directly controls the duration of sediment reworking by waves, and thus the ridge dynamics. Flume modelling was used to investigate the impact of low‐frequency tidal cycles on beach ridge evolution and internal architecture. The experiment was performed using natural bioclastic sediment, constant wave parameters and low‐frequency variations of the mean water level. The morphological response of the beach ridge to water level fluctuations and the preservation of sedimentary structures were monitored by using side‐view and plan‐view photographs. Results were compared with the internal architecture of modern bioclastic beach ridges in a macrotidal chenier plain (Mont St. Michel Bay, France) surveyed with ground‐penetrating radar. The experimentally obtained morphologies and internal structures matched those observed in the field, and the three ridge development stages identified in ground‐penetrating radar profiles (early transgressive, late transgressive and progradational) were modelled successfully. Flume experiments indicate that flat bioclastic shapes play a key role in sediment sorting in the breaker zone, and in sediment layering in the beach and washover fans. Water level controls washover geometry, beach ridge evolution and internal structure. Low water levels allow beach ridge stabilization and sediment accumulation lower on tidal flats. During subsequent water level rise, accumulated sediment becomes available for deposition of new washover units and for bayward extension of the beach ridges. In the field, low‐frequency water level fluctuations are related to the 4·4 year and 18·6 year tidal cycles. Experimental results suggest that these cycles may represent the underlying factor in the evolution of the macrotidal chenier coast at the multi‐decadal to centennial time scale.     

杭州湾南、北两岸潮滩变迁遥感动态调查

杭州湾是钱塘江河口区外海滨部分,其水动力条件、泥沙运移、沉积过程和地貌演变复杂。根据杭州湾区域遥感影像和地理地形等资料,通过综合分析研究,探讨了杭州湾南、北两岸潮滩的变迁过程。研究表明:杭州湾南、北两岸潮滩的发展程度不同,总体呈现南淤北侵的趋势。 43年来,北岸滩界变动范围基本限制在 1955年潮滩界线之内,潮滩面积呈负增长;南岸扇顶滩界外移 12550m,外移速率达 + 292m/a。潮滩的发展具有空间、时间上的差异性,南岸潮滩淤涨集中在 1955～1963年和 1977～1987年;北岸负增长则集中在 1955～1963年及 1987～1998年。进一步研究还发现:潮滩发育的差异性主要受岸线的空间地貌位置的影响。     

锦州湾泥沙来源、洄淤状况与建港条件分析

锦州湾泥沙主要来源于沿岸入海河流的输送,外海水体的携带与沿岸、岛屿蚀余物质的补给。每年进入湾内的泥沙总量约为３３—３５万吨,假如这些泥沙不再向湾外流出,在湾内作均匀分配沉积,则相当于在湾底铺上５ｍｍ厚的土。水准和水深重复测量表明,潮滩以稳定的弱堆积为主,水下浅滩基本处于稳定状态。该湾在非正常情况下产生骤淤的可能性不大。综合建港条件良好。     

河北省怀来新元古代长龙山组沉积相研究

河北省怀来新元古代长龙山组主要为一套富含Ｃｈｕａｒｉａ等宏观藻类化石的碎屑岩沉积组合。对剖而的岩相分析及地球化学的研究,确定了潮坪、浅水陆及海滩等三种沉积相。由此提出了长龙山组的沉积相模式。长龙山组表现为三种沉积相的周期性叠置,组成了两个碎屑岩沉积序列。长龙山组的下部序列由潮坪相到浅水陆棚相再退回到海滩相;上部序列由浅水陆棚相及上组成。Ｃｈｕａｒｉａ等宏观藻类化石主要发育在浅水陆棚相的滨外页岩亚相     

Longshore grain size trends in the Kakinada-Mulapeta Beach,east coast of India

Shore-normal and shore-parallel variations in grain size statistics of beach sand have been studied over a period of one year along the Kakinada-Mulapeta coast. The southern beaches of this coast have been accretionary while the northern ones erosional since 125 years. The grain size gradings, beach and nearshore processes help in identifying (i) the Groins-fishing harbour beach influenced predominantly by the tidal regime. (ii) the Mulapeta-Vakalapudi beach influenced by refracted wave regime and (iii) the Vakalapudi-fishing harbour beach affected by both wave and tidal regimes at relatively subdued levels.     

巨型人工采砂坑对伶仃洋自然演变的影响

伶仃洋内建有华南最大的两个主枢纽港及相连的深水航道,长期保持"三滩两槽"稳定格局是广州港选择西槽开发深水航道并取得成功的关键基础。2008年以后,由于在中滩上人工采砂,现已形成了容积达7×108m3的巨型采砂坑,直接影响了伶仃洋的滩槽演变。采用现场调查和数值模拟等方法,分析了采砂活动过程中对周围水体及地形的影响,指出采砂区域水体含沙量为1.5~2.8kg/m3,最大可达5kg/m3以上,远大于采砂前0.2kg/m3,可引起附近海床淤积,对港珠澳大桥桥区的海床稳定也会产生影响。同时,采砂坑形成后潮位、潮流、潮量出现较大改变的区域主要在采砂坑及其附近水域,表现为潮位下降（小于1cm）,潮流减小,采砂坑内以泥沙回淤为主（33cm/a）,坑周围海床呈侵蚀冲刷状态,南侧冲刷较大。此外,现状条件下采砂坑以回淤为主,回淤时间预计20年,但在2#、3#采砂坑或2#、4#采砂坑连通等不利状况下,有可能形成新的潮流通道,改变现有"三滩二槽"的格局,对目前已有航道维护和港口生产造成不利影响。     

Sedimentology and stratigraphy of a transgressive, muddy gravel beach: Waterside Beach, Bay of Fundy, Canada

Sediments exposed at low tide on the transgressive, hypertidal (>6 m tidal range) Waterside Beach, New Brunswick, Canada permit the scrutiny of sedimentary structures and textures that develop at water depths equivalent to the upper and lower shoreface. Waterside Beach sediments are grouped into eleven sedimentologically distinct deposits that represent three depositional environments: (1) sandy foreshore and shoreface; (2) tidal‐creek braid‐plain and delta; and, (3) wave‐formed gravel and sand bars, and associated deposits. The sandy foreshore and shoreface depositional environment encompasses the backshore; moderately dipping beachface; and a shallowly seaward‐dipping terrace of sandy middle and lower intertidal, and muddy sub‐tidal sediments. Intertidal sediments reworked and deposited by tidal creeks comprise the tidal‐creek braid plain and delta. Wave‐formed sand and gravel bars and associated deposits include: sediment sourced from low‐amplitude, unstable sand bars; gravel deposited from large (up to 5·5 m high, 800 m long), landward‐migrating gravel bars; and zones of mud deposition developed on the landward side of the gravel bars. The relationship between the gravel bars and mud deposits, and between mud‐laden sea water and beach gravels provides mechanisms for the deposition of mud beds, and muddy clast‐ and matrix‐supported conglomerates in ancient conglomeratic successions. Idealized sections are presented as analogues for ancient conglomerates deposited in transgressive systems. Where tidal creeks do not influence sedimentation on the beach, the preserved sequence consists of a gravel lag overlain by increasingly finer‐grained shoreface sediments. Conversely, where tidal creeks debouch onto the beach, erosion of the underlying salt marsh results in deposition of a thicker, more complex beach succession. The thickness of this package is controlled by tidal range, sedimentation rate, and rate of transgression. The tidal‐creek influenced succession comprises repeated sequences of: a thin mud bed overlain by muddy conglomerate, sandy conglomerate, a coarse lag, and capped by trough cross‐bedded sand and gravel.     

Evolution and stratigraphy of a regressive barrier/backbarrier complex: Kiawah Island, South Carolina

Analysis of 75 vibracores from the backbarrier region of Kiawah Island, South Carolina reveals a complex association of three distinct stratigraphic sequences. Beach ridge progradation and orientation-controlled backbarrier development during the evolution of Kiawah Island, and resulted in deposition of: (1) a mud-rich central backbarrier sequence consisting of low marsh overlying fine-grained, tidal flat/lagoonal mud; (2) a sandy beach-ridge swale sequence consisting of high and low marsh overlying tidal creek channel and point bar sand, and foreshore/shoreface; and (3) a regressive sequence of sandy, mixed, and muddy tidal flats capped by salt marsh that occurs on the updrift end of the island. Central backbarrier deposits formed as a result of the development of the initial beach ridge on Kiawah Island. Formation of this beach ridge created a backbarrier lagoon in which fine-grained estuarine and tidal flat mud accumulated. Washovers, oyster mounds, and tidal creek deposits form isolated sand and/or shell-rich lenses in the lagoon. Spartina alterniflora low marsh prograded into the lagoon as the tidal flats aggraded. Barrier progradation and sediment bar-bypassing at Stono Inlet created digitate beach ridges on the northeast end of Kiawah Island. Within the beach-ridge swales, tidal flats were disconformably deposited on shoreface and foreshore sand of the older beach ridges. Tidal creek drainage systems evolved to drain the swales. These rapidly migrating creeks reworked the tidal flat, foreshore, and shoreface sediments while redepositing a fining-upward sequence of channel lag and point bar deposits, which served as a substrate for salt marsh colonization. This resultant regressive sedimentary package marks the culmination of barrier island development and estuary infilling. Given enough time and sedimentation, the backbarrier sequence will ultimately prograde over the barrier island, reworking dune, beach, and foreshore sediments to form the upper sand-rich bounding surface of the barrier lithosome. Preservation of the regressive sequence is dependent upon sediment supply and the relative rate of sea-level rise, but the reworking of barrier islands by tidal inlets and migrating tidal creeks greatly alter and complicate the stratigraphic sequence.     

四川盆地下寒武统龙王庙组岩相古地理特征和沉积模式

在系统吸收前人研究成果的基础上,通过露头、岩心和薄片观察,结合测井和区域地质资料,探讨了四川盆地龙王庙组岩相古地理特征及沉积模式。研究认为:四川盆地及周缘在寒武系龙王庙组沉积时期为远端变陡的缓坡环境,自西向东依次发育近岸潮坪—内缓坡—中缓坡—外缓坡相带。其中四川盆地主体位于内缓坡,它又可划分为浅水内缓坡、局限内缓坡和开阔内缓坡三个古地理环境,发育颗粒滩、滩间海、正常湖、局限湖和潮坪等5种亚相。在纵向上龙王庙组沉积期经历了上下两个海侵—海退的短期旋回。古地貌较高的浅水内缓坡主要发育上旋回,以颗粒滩和滩间海亚相为主,沉积了较厚层的砂屑白云岩、鲕粒白云岩、细晶白云岩、粉晶白云岩等。局限内缓坡和开阔内缓坡的下旋回发育了2套完整的湖—台坪组合,岩性以泥晶灰岩为主。上旋回普遍发生了白云石化,水体能量总体较弱;其中在局限内缓坡由于水流不畅、环境局限,以上旋回发育膏盐岩为特征。四川盆地及周缘缓坡台地的沉积特征和沉积模式的主控因素有三个:即古构造控制了沉积体系和沉积相类型;海平面升降控制了沉积物的垂向叠置和演变;古地貌和水体能量控制了沉积物类型和沉积微相分异。据此预测了安岳—南充—剑阁一带为有利储层的分布区。     

A data-driven approach for analyzing dynamics of tide–aquifer interaction in coastal aquifer systems

Analysis of tidal effects on aquifer systems plays an important role in coastal aquifer management owing to various hydrological, engineering and environmental problems in coastal areas. Using the real-world data of unconfined and confined aquifers, a data-driven approach is presented in this study for the analysis of tide–aquifer interaction in coastal aquifers. Six analytical tide–aquifer interaction models were selected which take into account the effects of vertical beach, sloping beach, tidal loading, aquifer leakage, outlet capping, and combined leakage and outlet capping on tide-induced groundwater fluctuations. The tide–aquifer interaction datasets were obtained from the Konan groundwater basin (unconfined aquifer) of Japan and the Dridrate groundwater basin (confined aquifer) of Morocco. The analysis of the results obtained by the sloping beach model revealed that for a given beach slope, the amplitude of groundwater level increases with an increase in aquifer diffusivity and a decrease in aquifer thickness. However, no significant effect of beach slope was observed in this study at unconfined sites for all the datasets. The influence of tidal loading was found to be considerably less for all the three confined sites. Further, the analysis of the results of the leakage model indicated that with an increase in leakage into the aquifer, the amplitude of groundwater level as well as the phase shift (time lag) decreases. Of all the confined and unconfined datasets, only two confined sites were found to be affected by outlet capping. Overall, it is concluded that the coastal beach bordering the Konan basin is not significantly sloping, the contribution of tidal loading to tide-induced groundwater fluctuations in the Dridrate aquifer is not appreciable, and that the aquifer leakage and outlet capping do not exist at the unconfined sites under investigation.