砂质海岸岸滩侵蚀演变模式探讨——以山东南部海岸侵蚀岸段的岸滩演变为例

在分析山东南部海岸几十年来的地形观测资料的基础上，运用砂质海岸等深线变化预测理论，建立该区的岸滩侵蚀演变预测模型，研究了该区域岸滩演变规律。实测资料验证表明：预测结果合理，基本反映了本区岸滩演变的特征。     

The 3D simulation and optimized management model of groundwater systems based on eco-environmental water demand

Through the study of mutual process between groundwater systems and eco-environmental water demand, the eco-environmental water demand is brought into groundwater systems model as the important water consumption item and unification of groundwater’s economic, environmental and ecological functions were taken into account. Based on eco-environmental water demand at Da’an in Jilin province, a three-dimensional simulation and optimized management model of groundwater systems was established. All water balance components of groundwater systems in 1998 and 1999 were simulated with this model and the best optimal exploitation scheme of groundwater systems in 2000 was determined, so that groundwater resource was efficiently utilized and good economic, ecologic and social benefits were obtained.     

Straight river: its formation and speciality

Straight river is generally regarded as one of the typical river patterns in conventional classifications in terms of their channel plain landforms. However, very few straight patterns were found to be distributed in wider spatial and temporal spans in the self-adjusted fluvial rivers. Thus, the questions occur such as that is it possible for a channel takes on a stable straight pattern? What are the main factors controlling the processes of the river pattern formation and transformation from a straight to other patterns? Various theories and hypotheses including geomorphic threshold hypothesis, the extreme hypothesis on energy dissipation rate, the stability theory, etc. have been developed to explain the aforementioned questions, but none of them is sound for the explanation to the straight-river formation. From the modern fluvial plain patterns, the straight patterns are not as stable as other typical patterns which occurred in nature; from the historic records of the river sedimentation, no apparent evidence was found to support the stable straight river evolution. Based on the analysis of existing theories, observations, evolvement processes of the channel patterns in the experimental results, this paper concluded that the straight pattern should not be included as one of the typical patterns that are self-formed and developed. This study is of importance to understanding of the river pattern formation and transformation.     

Eco-environment range in the source regions of the Yangtze and Yellow rivers

Based on geographical and hydrological extents delimited, four principles are identified, as the bases for delineating the ranges of the source regions of the Yangtze and Yellow rivers in the paper. According to the comprehensive analysis of topographical characteristics, climate conditions, vegetation distribution and hydrological features, the source region ranges for eco-environmental study are defined. The eastern boundary point is Dari hydrological station in the upper reach of the Yellow River. The watershed above Dari hydrological station is the source region of the Yellow River which drains an area of 4.49×104 km2. Natural environment is characterized by the major topographical types of plateau lakes and marshland, gentle landforms, alpine cold semi-arid climate, and steppe and meadow vegetation in the source region of the Yellow River. The eastern boundary point is the convergent site of the Nieqiaqu and the Tongtian River in the upstream of the Yangtze River. The watershed above the convergent site is the source region of the Yangtze River, with a watershed area of 12.24×104 km2. Hills and alpine plain topography, gentle terrain, alpine cold arid and semi-arid climate, and alpine cold grassland and meadow are natural conditions in the source region of the Yangtze River.     

城市水资源的合理利用与可持续发展

自20世纪80年代以来，由于工业的高速发展，中国城市已由180座猛增至666座，城市人口和城市需水量都迅猛增长，造成城市水资源紧缺。城市发展也使污染问题日益严重，直接对水资源造成破坏，影响人体健康。地下水超量开采，引起地面沉降、岩溶塌陷、海水入侵等地质灾害，造成严重经济损失。针对以上问题，本文探讨了城市水资源紧缺的原因及其对生态的影响，提出城市水资源的合理规划、合理利用以及开源节流、保护生态环境与防止地质灾害的相关措施。     

2003年2月14日石河子M5.4地震地形变异常及其演化分析

分析了新疆石河子M5.4地震前震中250 km范围内定点形变的观测资料,认为从2002年5月到震前,单测项异常随时间起伏,多台异常在时间上连续发展并呈增加趋势,震前20天位于震中附近的台站出现临震突变;异常在空间呈现由西向东、由南向北,逐渐向震中区发展的态势.与1996年沙湾M5.2地震前的形变异常进行比较,认为存在较大的差异.     

长江三角洲全新世环境演变与人地关系研究综述

综合分析了近20年来长江三角洲全新世环境演变与人地关系研究的进展，着重对长江三角洲的形成与演变、环境演变与人类活动、人地关系的历史演变、古环境研究方法等进行了综述。指出今后研究的主要内容，包括多种环境替代指标的相互验证，高分辨率研究，定量研究，加强环境质量的时空演变研究，加强综合研究，寻求人地关系协调发展的途径。     

喀斯特土地利用变化及其区域生态环境效应--以广西都安瑶族自治县为例

从土地利用转移类型、空间格局变化定量分析、动态变化预测模型等方面分析近20年都安土地利用变化,进而对其生态环境质量变化进行定量分析,得出结论:都安各乡(镇)生态环境质量改善与恶化在很大程度取决于裸岩地扩展与收缩,土地利用时空变化与区域生态环境质量的区域差异有很大相关性。     

2010—2020年黄河下游河南典型灌区浅层地下水中砷和氟的演化特征及变化机制

黄河下游典型灌区河南段是豫北平原重要的农业种植区。该地区浅层水质整体较差,因常用于作物灌溉或家畜饮用,会对人体健康产生风险,因此对该地区地下水中砷与氟浓度变化特征和机制的研究将有助于提高对该地区地下水污染的认识水平。本文基于2010年和2020年在灌区范围内采集的327组浅层地下水样品,研究区内地下水砷和氟分布情况,并在此基础上对比研究十年间灌区浅层地下水中砷、氟的演化特征,探索分析砷与氟浓度及空间变化机制。研究结果表明：该地区浅层地下水中存在砷与氟超标问题,2020年浅层地下水中高砷（砷浓度大于10μg/L）和高氟（氟浓度大于1mg/L）的样品数量分别占总数的26.1%和26.06%。高砷水分布在太行山前洼地与黄河冲积平原等泥沙互层结构的沉积环境中,还原性较强,同时地下水径流不畅,较强的阳离子交换作用使得其所处环境中Ca²⁺浓度较高。近十年间砷浓度增加的水样占总数31.8%,砷浓度减少的水样占36.7%。砷浓度的增长（减少）是地下水还原性增强（减弱）使得锰氧化物溶解释放（吸附）导致。近十年间不同地区农业灌溉和水源置换等用水方式导致水位变化是引起砷浓度变化的潜在因素。高氟水主要分布在河南新乡与濮阳的黄河沿线,氟离子浓度受到沉积物中萤石等钙质矿物溶解影响,使得高氟地下水出现在低钙环境中。近十年间研究区中氟离子浓度减少的占总数60.2%,氟离子浓度增加的占32.1%,整体变化趋势向好,但是高氟区中氟离子浓度继续增加。氟浓度的变化同样受到Ca²⁺变化影响,在Ca²⁺浓度降低（升高）时氟浓度进一步升高（降低）。地下水中氟升高地区分布在黄河沿线,因此受到黄河水补给影响较大,地下水径流条件较好,阳离子交换作用减弱,使得Ca²⁺浓度降低,此时地下水中砷浓度受到环境影响而降低,因此研究区氟增加地区中砷与氟的分布和演化呈现反向关系。     

潮滩演变规律在围堤选线中的应用——以江苏辐射沙洲内缘区为例

滩涂围垦是沿海地区耕地占补平衡的重要手段。如何进行合理的围堤选线,尽可能减小围堤对潮滩水沙环境的影响,使匡围后的潮滩演变不影响海堤安全,是围海工程设计时必须考虑的问题。以江苏辐射沙洲内缘区仓东垦区匡围工程为例,运用潮滩均衡态概念框架,对条子泥西侧岸滩平均高潮位点变化、师地岛形成及潮沟活动性等潮滩演变特征及趋势进行了分析,并重点探讨了其在围堤选线中的应用。