Influences of land use/cover on water quality in the upper and middle reaches of River Njoro, Kenya

Data from 10 sampling sites along the River Njoro are used to examine the contribution of nutrients from upstream land uses draining each of the sampling sites. The data also are used to assess whether both the proportion of land uses and the size of the subwatersheds account for the variability in water quality in the River Njoro watershed. Geographical Information System analysis was used to determine the spatial distribution of land‐cover types and subwatersheds contributing run‐off to the sampling sites in the River Njoro. Standard Digital Elevation Model‐based routines were used to establish the watershed area contributing run‐off to each sampling site. Water and sediment samples were collected for chemical analysis, and the nutrient levels were related to the upstream land‐use types and the size of the subwatersheds. The mid‐stream portion of the River Njoro (near Egerton University) accounts for the highest nutrient contributions. The percentage contribution is magnified by additions from industrial, human settlements and agricultural land uses around the University. There is a significant decrease in nutrient levels downstream, however, indicating natural purification as the river flows through an area of large‐scale farming with intense, well‐preserved riparian and in‐stream vegetation. Steep slopes of the land upstream of Egerton University enhance erosion and nutrient losses from those subwatersheds. Mixed small‐scale agricultural and bare lands contribute over 55% of the phosphorus load to the upper and mid‐reaches of the River Njoro. The size of the subwatershed accounts for about 53% of the variability in the soluble phosphorus in the river. The land‐use subwatershed proportions are important for characterizing and modelling water quality in the River Njoro watershed. Upland land uses are as important as near‐stream land uses. We suggest that conservation of intact riparian corridor along the river and its tributaries contributes significantly to natural purification processes and recovery of the ecological integrity of the River Njoro ecosystem.     

河流生态用水流量确定新方法研究

新修改的《中华人民共和国水法》明确提出要维持江河的生态用水流量,以维持水体的自然净化能力,确保健康河流。经过对多种计算方法分析、比较,提出了河流生态用水流量的内涵与计算方法,该法简单可行,不但有一定的理论价值,而且有一定的实用价值,可供实际工作参考使用。     

灞河生态治理工程模型试验研究

通过模型试验 ,对位于西安市东郊因采沙使河道破坏严重的灞河河段进行了复现试验和研究 ,并以此为依据 ,通过优化比较为设计部门提供了合理的橡胶坝坝址和坝座高程。在此基础上 ,又对建坝后橡胶坝对上下游冲淤变化的影响进行了试验研究和分析 ,解决了工程设计中的一些关键技术问题     

生态环境的恶化与乡村社会控制--以清代徽州的棚民活动为中心

从明后期开始进入徽州地区的外地棚民，利用当地丰富的自然资源，进行各种经济活动。在当时的社会条件制约下，此类经济活动耗费了大量的资源，破坏了徽州农村的生态环境，损害了地方和国家的利益。针对这一问题，清代徽州乡村社会各种民间力量和官方联合展开了一场声势浩大的驱禁棚民运动，取得了预期效果。     

莫莫格湿地生态演变及水源解决途径探析

湿地的生态演变是区域性生态演变的前奏，而水是生态环境的控制性因素。     

生态城市与水利现代化

对天津及其滨海新区生态城市水利建设进行了分析。研究了在淡水资源极度匮乏的条件下,有效开发利用非常规水资源的必要性、重要性和现实性。认为天津市对水资源应遵循节水、治污、高效配置,妥善处理生活、生产、生态之间的关系,力求平衡调配。供水水源应是多元的,增加非常规水资源(污水、海/咸水、雨/洪水)的利用,同时增加可用地下水,外调来水等,逐步进入可持续发展配置。     

建设项目生态经济效益分析

从建设项目对生态经济的影响，建设项目生态经济的评价以及自然资源价值对建设项目评价的影响，论证了建设项目与生态经济对立统一的关系，提出了建设项目环境保护的重要性，建设性的提出了如何进行建设项目中的生态经济效益分析和评价，具有一定的现实意义。     

国有资产管理及营运模式研究

加入WTO ,中国企业与全球经济融会一体 ,企业人才国际化势在必然。为此 ,必须树立企业人才国际化战略的紧迫感 ,明确企业人才国际化的深层内涵 ,致力营造企业人才国际化的生态环境。     

对外贸易对我国生态环境影响的实证分析

学术界对对外贸易与生态环境的关系还存在争论。本文建立了对外贸易影响环境的投入产出分析模型，并以此模型为基础，利用我国2002年投入产出表和我国能源消费数据，对我国2002年对外贸易对环境的影响进行了实证分析，得出了对外贸易有利于我国生态环境改善的结论。