Occurrence of severe floods in the Salado River Basin,Buenos Aires province,Argentina

Floods in the Salado Riverbasin, Argentina, seriously affect bothhuman activities and the environment.Inadequate and improper water managementaggravates the effects of natural extremeevents. The damage caused by the extremeflood in 1993 cost US$507 million,affected 14,500 farmers and flooded6,500,000 ha within the basin. This paperanalyses natural trends within the rainfalland riverflow records, and considers thepossible effects of human interference. Theriver basin is mainly underlain byimpermeable soils with a high water table.The soil factor and the low topographicgradients often produce surface run-off withslow lateral drainage. Very often, heavyrainfall associated with high soil moisturecontent leads to flooding of the basin.Three major flood events that have occurredsince 1960 have been analysed. Floodoccurrences have been placed in the contextof precipitation variability and soil waterstorage. The precipitation records of twolong-term stations in the basin (Junin andDolores) show an increasing trend and thisis due to rainfall increases in the warmseason. However, none of the rain eventsreached the probable maximum precipitationof 100 year return period. The dischargerecords of the Salado River are comparedwith the pattern of the ElNiño/Southern Oscillation and it isfound that only the May discharge anomaliesare weakly related to the El Niñodriven climate variability. Results fromthis study are useful for the formulationof flood mitigation measures. The paperconcludes with a consideration of the floodmitigation policy developed in PlanMaestro.     

滏阳河流域的水资源问题

根据对华北地区水资源短缺最严重的滏阳河流域的实证研究表明,随着部门和上下游用水者之间用水竞争程度的加剧,流域从开放向闭合的转变,地下水位的逐年下降及引致的环境问题,节水的空间也变得十分有限。解决未来水资源短缺的问题很大程度上将依赖于如何运用政策、制度和经济措施实现水资源的优化配置和综合管理,提高灌区的运行绩效和实现有效的产权制度创新。     

云南省境内怒江流域水质变化趋势分析

用线性回归方法对云南省境内怒江流域1980年～2000年的水质状况及污染物输送量进行长系列趋势分析.怒江流域污染物入河量呈上升趋势,河流总体水质有下降趋势,主要支流水质下降程度高于干流,并结合面源对河流水质贡献率大的特点,提出流域面源污染防治对策及建议.     

小清河流域砷含量及其存在形态的研究

对小清河流域的砷含量进行了监测分析 ,并采用形态分析方法对砷的存在形态进行了分析研究。结果发现该流域水土受到一定程度的砷污染。从形态分析看 ,土壤、底质中以无机砷为主 ,而无机砷又以As(V)为主 ;河水中以有机砷为主     

太湖湖西洞天福地

太湖湖西苏皖浙交界地域 ,晚古生代—早中三叠世纪沉积的石灰岩发育 ,厚度大 ,质纯 ,加上滨临太湖 ,具有优越的地理和气候环境 ,因而形成数十个岩溶洞穴。著名者有 :宜兴南部善卷洞、张公洞、灵谷洞、幕蠡洞 ,广德北部太极洞和湖洲以北黄龙古洞和黄龙宫等洞天福地     

Assessment of nitrogen leaching from arable land in large river basins: Part I. Simulation experiments using a process-based model

A two-step procedure for analysing nitrogen leaching from arable land in large river basins is suggested: (1) application of a process-based dynamic model for a set of representative conditions in a large river basin to simulate water and nitrogen fluxes and (2) development of a fuzzy-rule based metamodel using the simulated nitrogen fluxes in Step 1 as a training set. After that the metamodel can be used for rapid assessment of water quality inside the considered ranges of parameters, describing natural conditions and management practices. This paper describes Step 1 of the procedure. Step 2 is described in an accompanying paper (Haberlandt et al., Ecological Modelling 150 (3) (2002) 277–294). The advantage of this approach is that it combines the ‘process-based foundation’ with the resulting simplicity of the metamodel. Simulation experiments for analysing nitrogen (N) leaching from arable land were performed using the Soil and Water Integrated Model (SWIM) for a set of representative conditions in the Saale basin (23 687 km²) in Central Europe. The Saale River is one of the main tributaries of the Elbe. In advance, hydrological validation of the model was done for the whole Saale basin and validation of nitrogen dynamics was fulfilled in two mesoscale sub-basins of the Elbe. For the simulation experiments the drainage basin area was sub-divided into five climate zones and nine representative soil classes were chosen. The basic rotation and fertilisation schemes were established using regional information obtained from literature. In addition, the effects of changing the basic rotation to more/less intensive ones and changing fertilisation rates by 50% increase/decrease were studied. The ranges of simulated nitrogen fluxes for the basic rotation and fertilisation schemes are comparable to available regional estimates and differences between sub-regions and soils are plausible. The relative importance of natural and anthropogenic factors affecting nitrogen leaching for the Saale River basin was as follows: (1) soil, (2) climate, (3) fertilisation rate and (4) crop rotation. The simulation experiments provide a basis for a fuzzy-rule based metamodel approach, which aims at rapid water quality assessment of large regions.     

我国水污染防治的战略与政策的探讨

我国大部分城市污水的95%未经处理排放入水体,城市地区的水质有继续恶化的趋势,甚至许多城镇的下水管网尚不完善.随着城市化和工业化的发展,城市污水将继续增加.我国在污水处理中投资不足和水污染规模大这一不相适应的矛盾将会在相当长的一个时期内存在.解决我国水污染的根本原则是供求最大的费用—有效性.未来水污染防治的政策要点是:1.集中力量于源头削减污染产生量;2.建立按总量控制的流域级水污染防治的方法和示范工程;3.在投资和管理体制上建立以城市污水集中处理的市场经济刺激机制.     

鲁中王氏组的形成环境及其构造意义

本文将晚白垩世王氏组的沉积相划分为五类:湖盆陡岸浊积扇相,洪积扇沉积相、滨—浅湖前缘斜坡相、次深湖相、湖湾相。并详细研究了微相特征。王氏组沉积特征所反映的沂沐断裂带的活动特点是:先为徐缓的脉动,而后是陡然激烈的断陷,故造成了补偿性沉积与超补偿性沉积的叠置。王氏组砂岩平均化学成分表明:马站盆地具孤后盆地性质。     

我国淡水湖泊资源开发探讨——以东平湖为例

本文阐述了我国淡水湖泊具有调节河川径流、发电、灌溉、航运等功能。并以东平湖为例,系统论述了它们的资源特征(自然环境、理化特征、鱼类生境、旅游环境),及其利用开发现状,并分级分析了它们各自的生态环境、生态系统特点。指出了我国淡水湖泊存在的主要问题:入湖水源不足,工业废污水的污染,水工建筑物阻隔河湖通道,滞洪淤积等,导致了水域生态环境恶化,溯河入湖物种绝灭,湖体湮废等。最后提出了设计湖体水生资源得以开发的流域水资源调节控制规划;加强流域水土保持;有计划地进行湖底清淤;疏竣河湖接口通道,添建鱼道;编制利于水生动、植物生境的水利工程运营方案,设计高效静水资源开发方案等整治对策。     

吐鲁番盆地的生态灾害及其调控

吐鲁番盆地的生态灾害具有种类多、危害面广、危害程度深等特征，并严重制约着该区绿洲经济的持续稳定发展。本文分析了每种生态灾害发生的原因、危害程度及地区分布，并提出了生态灾害调控的基本原则；综合整体性、区域分异性、持续性．最后探讨了该地生态灾害调控的一些具体措施。