ASSESSING CHANGES IN WATERSHED FLOW REGIMES WITH SPATIALLY EXPLICIT HYDRAULIC MODELS1

ABSTRACT: Urbanization, farming, and other watershed activities can significantly alter storm hydrographs and sediment erosion rates within a watershed. These changes routinely cause severe economic and ecological problems manifested in the form of increased flooding and significant changes in channel morphology. As the activities within a watershed influence the hydrologic, hydraulic, and ecological conditions within a river, interdisciplinary approaches to predict and assess the impacts that different land uses have on streams need to be developed. An important component of this process is ascertaining how hydrologic changes induced by specific watershed activities will affect hydraulic conditions and the accompanying flood levels, sediment transport rates, and habitat conditions within a stream. A conceptual model for using spatially explicit (two‐dimensional) hydraulic models to help evaluate the impacts that changes in flow regime might have on a river is presented. This framework proposes that reproducing and quantifying flow complexity allows one to compare the hydraulic conditions within urban, urbanizing, and non‐urban streams in a more biologically and economically meaningful way. The justification, advantage, and need for such a method is argued through the results of one‐ and two‐dimensional hydraulic model studies. The implementation of this methodology in watershed urbanization studies is described.     

城市化进程中的土地资源优化配置

土地资源的优化配置是目前我国城市化进程中面临的重要问题.在分析城市化的内涵和我国城市化进程的基础上,运用定性与定量相结合的方法,明确了城市化进程与土地资源优化配置的密切关系,阐述了城市化进程中土地利用存在的四大问题,提出了五大对策,以确保城市化进程中土地资源的优化配置.     

大熊猫主食竹种秆龄鉴定及种群动态评估

四川西南部和西北部中山、亚高山森森下，竹源丰富，其中：拐棍竹和冷箭竹是大熊猫的主食竹种，作者１９８２－１９８７年进行竹类生态研究；通过固定样方观察和带标志茎秆记录分析，发现竹杆和笋箨的颜色，以及主枝叶鞘与枝节数的变化和竹子秆龄的增长密切相关，可以作为鉴定竹秆年龄的依据。根据竹子的秆龄结构，应用负指数函数模型，可以估算竹子种群的增长量和死亡率，评估竹子的种群动态变化，可为主管部门制定保护大熊猫规划规     

职业人群健康监护信息管理系统的研究

健康监护信息管理系统可以对尘肺发生、发展情况进行跟踪与监视。也反映了对这一职业人群职业病监测的信息从收集、贮存到处理、利用,建立一个完整的反馈系统的重要意义。该系统结构合理、功能性强、程序设计简洁清晰、运行可靠,达到了规范化、标准化的要求。通过对这一职业人群的医学监护,可以及时分析全省工业中尘肺发展动态,从而为防治尘肺的科学决策提供可靠依据,并为深入开展尘肺病因学、流行病学、卫生学科研工作奠定基础。     

PROJECTION OF URBANIZATION EFFECTS ON RUNOFF USING CLARK INSTANTANEOUS UNIT HYDROGRAPH PARAMETERS1

ABSTRACT: To alleviate serious flooding problems brought upon by rapid urbanization in the Beargrass Creek watershed, located in Louisville, Kentucky, the U.S. Army Corps of Engineers undertook a major flood study in 1973. In order to predict flood conditions in 1990, the year when the watershed was expected to undergo complete urbanization, trends in the Clark Instantaneous Unit Hydrograph (Clark IUH) parameters were utilized to determine the 1990 unit hydrograph and flood conditions. Based on the results from this flood study, this paper demonstrates the applicability of using projected Clark IUH parameters for modeling future runoff conditions in an urbanizing watershed. Values of these parameters, as estimated from maximum annual historical flood data, are used to develop regression models for predicting future Clark IUH parameters. Using the projected parameters, selected annual flood events since 1973 are simulated in order to verify the accuracy of these projections. Results show a close correspondence between the simulated and observed flood characteristics. Hence, the use of projected Clark IUH parameters is an appropriate procedure for modeling future runoff conditions in an urbanizing watershed.     

MUNICIPAL AND INDUSTRIAL WATER SUPPLY IN CIUDAD JUAREZ,MEXICO1

Rapid industrialization and population growth in the north Mexican desert city of Ciudad Juarez are placing a serious strain on the city's municipal water resources. Water deliveries and service area have more than doubled over the past decade, and plans for additional expansion are presently being implemented. This expansion is already contributing to water table declines and salinity increases in the Mexican portion of the Heuco Bolson, the sole source of water for the city. Continued mining of the limited fresh water reserves should produce serious water supply problems in the near future. New estimates of future water consumption incorporated into a digital aquifer simulation model indicate that these problems may show up much sooner than was anticipated in previous investigations. The results of this study point to the need to accelerate the gathering of basic data on alternative water resources. The problems faced by Cd. Juarez are illustrative of the kinds of difficulties likely to confront other rapidly developing cities of the arid zone.     

Effects of tourist population pressure on pollution of coastal seas

Coastal tourism continues to be an important industry for many countries. Improper planning, however, frequently results in the deterioration of the coastal waters in newly opened tourist resorts. Avoidance of this situation can be achieved by predetermining the bearing capacity of the site, which is very costly and time consuming. After an extensive study, the author previously had developed an equation by which the effects of the increase in tourist population on coastal water quality can be determined. The microbial pollution, which is indicated by coliform concentration, is a function of human population, intensity of light, turbidity, temperature of seawater, human population density, and the coastal characteristics coefficients. By using the equation, the bering capacity of a site can be determined easily. The purpose of the present study is the verification of the equation. To achieve this, a study was conducted at another tourist resourt, Cesme, where 1764 observations were made. The results, regardless of the small differences in the coefficients obtained, indicate that the proposed method can be used to determine the bearing capacity of the system as well as the extent of microbial pollution. This accelerates and simplifies the prediction and the prevention of possible negative effects that can be caused by opening coastal areas to tourism.     

Response of Georges Bank cod to periodic and nonperiodic oil spill events

In the management of conflicting dual-resource systems such as continental shelf hydrocarbon extraction and commercial fishing operations, it is necessary to consider the possibility of repeated impact events. The potential magnitude of impacts on Georges Bank fisheries of single oil spill events has been addressed in detail elsewhere (Reed and Spaulding 1979, Reed and others 1980, Spaulding and others 1982). An oil spill-fishery impact estimation model, implemented for the Georges Bank cod fishery (Reed and others 1980), has been used to investigate the potential for nonlinear biological responses to periodic and nonperiodic repetitive spill events. Prerecruit mortality equations incorporating young-of-the-year as well as adult-juvenile interactions, perform acceptably vis-à-vis the historical catch record, but show highly variable behavior under recruitment reductions induced by periodic simulated spills. The results demonstrate the importance of selecting mathematical representations of biological and physical processes underlying population dynamics such that characteristic system behavior is adequately represented in both the time and frequency domains.     

基于TM影像的人口密度数字模拟——以北京地区为例

居住区影像是人口分布客观真实的定性表现,对这种定性的数据源进行合理量化即可获得人口实际分布数据。在分析TM影像各个波段特征的基础上,选取5、4、3波段进行图像逻辑运算,比较精确地提取出居住区影像。计算居住区面积并依据面积大小将居住区分为3类,根据人口户籍统计值计算出3类居住区相对的人口分布比例系数kj。然后生成与居住区矢量投影相同的1km网格,利用图层叠加统计每个网格内的居住面积lj,居住区矢量与区县界矢量叠加统计每个区县内的居住面积Am,计算网格人口分配系数ki×lj/Am,依据该系数对人口总数进行网格化模拟,以得到人口密度空间分布规律。以北京地区为试验区进行人口模拟,结果显示北京中心区最大人口密度为16 661人/km2,其他地区最大人口密度是8231人/km2。在模拟结果的基础上估算乡镇级人口,对比分析乡镇级估算人口和实际调查人口对结果进行验证,对比数据表明该算法所得到的人口分布与实际人口分布较为相符。     

重庆市城镇化外部环境分析

从自然资源与生态环境的角度、人文与社会环境的角度、工农业等经济发展的角度对重庆市城镇化建设中的外部环境进行了深入分析，探讨了重庆市城镇化建设中具有的自身优势和存在的主要问题，以期能为重庆市城镇化建设提供一定的理论依据和参考价值。