Characterizing Small Subbasins: A Case Study from Coastal Oregon

A fine-grained statisticaly robust probability sample of stream segments is used to compare two small (20,000 hectare) subbasins of the Tillamook watershed, north coastal Oregon. The two subbasins are matched with respect to several variables [size coastal climates], but vary in terms of geology and consequently land use. A total of 67 wadeable + non-wadeable sizes were identified for sampling in the two subbasins (combined) over two field seasons from a sampling universe consisting of the River Reach File 3 (blue lines on 1:100,000 maps). Target variables include an extensive array of physical habitat endpoints, selected water chemistry endpoints, species composition, and relative abundance of both benthic macroinvertebrates and fish. Field protocols generally followed those of the U.S. EPA's Environmental Monitoring and Assessment Program (EMAP).Eleven fish species were encountered, a typically low number for coastal Oregon streams. Exploratory analysis using nonmetric multidimensional scaling revealed that 92.4% of the variation in the fish assemblages could be explained with two ordination axes. Environmental factors related to stream size and substate were the most correlated to these axes. Further, stream segments for the two subbasins tended to map in different areas of species space. Therefore, we also give unweighted probability distributions for several of the factors that heavily on these two axes by subbasins, as well as probability distributions for chemical endpoints. Results from the subset of sites sampled during the first year (21 wadeable sites) reveal: 1) differences between samples from the two subbasins relates to dream size and substrate composition that are consistent with known differences in geology and land use, 2) unexpectedly minor differences between samples from the two subbasins for stream temperature, canopy cover, and dissolved oxygen, 3) differences between samples from the two subbasins for total P, and total N, possibly related to land use, and 4) unexpected differences in samples from the two subbasins for conductivity, probably related to geological factors. Sample size for each subbasin is low and therefore our samples cannot be taken to necessarily characterize either subbasin. However, our findings are consistent with a comprehensive assessment that had been previously produced for one of the two subbasins.All field work was completed in 8 weeks 3-person field crew. We conclude that rapid assessment protocols, based on probability samples at this level of resolution, can be a cost-effective approach to watershed analysis. This approach should be seen as a complement to, rather than a replacement for, systematic surveys that produced finer scale, reach specific information on factors such as channel complexity and cover relevant to in-stream restoration planning.     

城镇化对西苕溪大型底栖动物群落的影响

于2004—2010年5月对西苕溪流域20个参照点,5个中度干扰点以及2个重度干扰点的底栖动物进行了调查,共鉴定出74科190属226个种;受干扰后,底栖动物群落物种丰富度、EPT物种丰富度、Shannon-wiener多样性指数和B-IBI指数显著下降,BI指数显著升高。CCA分析结果表明,参照、中度和重点干扰样点的底栖动物群落差异明显。城镇化引起的溪流水温上升、营养盐升高、泥沙输入量增多和堤岸固化是导致溪流底栖动物群落退化的主要原因。     

大辽河水系表层沉积物中石油烃和多环芳烃的分布及来源

对大辽河水系的3条干流浑河、太子河和大辽河表层沉积物中石油烃(PHs)和多环芳烃(PAHs)分析表明,PHs总量分布范围为61.37～229.42 μg·g-1,PAHs总量分布范围为61.9～840.5 ng·g-1.石油烃含量远远高于已报道的世界其它河流和海洋沉积物中的含量,表明大辽河水系沉积物石油烃污染严重;而与世界其它河流和海洋地区相比,多环芳烃污染水平相对偏低.石油烃分布特征为太子河＞浑河＞大辽河;多环芳烃分布特征为大辽河＞太子河＞浑河.烃污染来源诊断表明,石油烃污染以陆源植物和人为污染输入为主,多环芳烃污染以石油燃烧热解为主,工业和生活污水是烃污染的主要来源.     

RELATIVE REGIONAL VULNERABILITY OF WATER RESOURCES TO CLIMATE CHANGE1

ABSTRACT: Changes in global climate may alter hydrologic conditions and have a variety of effects on human settlements and ecological systems. The effects include changes in water supply and quality for domestic, irrigation, recreational, commercial, and industrial uses; in instream flows that support aquatic ecosystems, recreation uses, hydropower, navigation, and wastewater assimilation; in wetland extent and productivity that support fish, wildlife, and wastewater assimilation; and in the frequency and severity of floods. Watersheds where water resources are stressed under current climate are most likely to be vulnerable to changes in mean climate and extreme events. This study identified key aspects of water supply and use that could be adversely affected by climate change, developed measures and criteria useful for assessing the vulnerability of regional water resources and water dependent resources to climate change, developed a regional database of water sensitive variables consistent with the vulnerability measures, and applied the criteria in a regional study of the vulnerability of U.S. water resources. Key findings highlight the vulnerability of consumptive uses in the western and, in particular, the southwestern United States. However, southern United States watersheds are relatively more vulnerable to changes in water quality, flooding, and other instream uses.     

MODELING DEVELOPED COASTAL WATERSHEDS WITH THE AGRICULTURAL NON-POINT SOURCE MODEL1

ABSTRACT: Many coastal states are facing increasing urban growth along their coast lines. The growth has caused urban non-point source nitrogen runoff to be a major contributor to coastal and estuarine enrichment. Water resource managers are responsible for evaluating the impacts from point and non-point sources in developed watersheds and developing strategies to manage future growth. Non-point source models provide an effective approach to these management challenges. The Agricultural Non-Point Source Model (AGNPS) permits the incorporation of important spatial information (soils, landuse, topography, hydrology) in simulating surface hydrology and nitrogen non-point source runoff. The AGNPS model was adapted for developed coastal watersheds by deriving urban coefficients that reflect urban landuse classes and the amount of impervious surface area. Popperdam Creek watershed was used for model parameter development and model calibration. Four additional watersheds were simulated to validate the model. The model predictions of the peak flow and total nitrogen concentrations were close to the field measurements for the five sub-basins simulated. Measured peak flow varied by 30 fold among the sub-basins. The average simulated peak flow was within 14 percent of the average measured peak flow. Measured total nitrogen loads varied over an order of magnitude among the sub-basins yet error between the measured and simulated loads for a given sub-basin averaged 5 percent. The AGNPS model provided better estimates of nitrogen loads than widely used regression methods. The spatial distribution of important watershed characteristics influenced the impacts of urban landuse and projecting future residential expansion on runoff, sediment and nitrogen yields. The AGNPS model provides a useful tool to incorporate these characteristics, evaluate their importance, and evaluate fieldscale to watershed-scale urban impacts.     

长江上游流域生态与可持续发展对策

概述了长江上游流域生态环境退化的现状和急需解决的问题,分析了生态环境退化的人为驱动因素和生态建设存在的问题,在此基础上提出了将长江上游作为一个流域整体进行跨地区、跨部门、跨学科的大联合攻关,强调“快速、经济、参与”为指导思想和原则,突出重点生态类型区域,开展关键技术试验示范攻关,发展以资源导向为主的区域经济,从而实现“近期遏制恶化,中期治理恢复,最终持续发展”的分阶段目标。     

登沙河流域水质监测断面优化研究

基于大连市登沙河监测断面的水质数据,采用系统聚类法、模糊聚类法和物元分析法进行优化,筛选代表性断面.结果表明,优化后的监测断面个数减少了40％,相关性较高的相邻断面个数由优化前的71％减少为54％,优化前、后的样本方差齐且均值无显著性差异.优化后的监测断面在显著提高效率的同时也确保了数据的代表性,使得断面重复布设情况得...     

Livelihood change and livelihood sustainability in the uplands of Lembang subwatershed, West Sumatra, Indonesia, in a changing natural resource management context

This paper analyzes livelihood change and livelihood sustainability of households in the upland part of the Lembang subwatershed, West Sumatra, in response to changes in the natural resource management context during the last decade. Using the sustainable livelihood framework (SLF), we measured livelihood changes at two separate points in time, 1996 and 2006, and assessed their environmental, economic, social, and institutional sustainability. We found that people with a low income had less access to capital assets than people from middle- and high-income groups. Our analysis revealed, however, that access to capital assets increased over time, and that poor households experienced economic improvement, indicating an overall increase in economic sustainability. Environmental sustainability, however, is threatened by intensive agricultural practices such as high agrochemical input and intensive soil tillage on steep slopes, leading to pollution and soil erosion. Social sustainability is also a matter of concern: while social exclusion has been reduced, income inequity has increased. Institutional sustainability is likely to remain uncertain, as local institutions for natural resource management are still weak, despite the fact that decentralization has been implemented during the last 8 years. External facilitation is needed to improve the livelihood of upland people while, at the same time, enhancing the sustainability of watershed management. Strengthening local institutions, conserving natural resources, and promoting environmentally sound agricultural practices are the three most important policies to be promoted within the watershed.     

秦皇岛市土地利用结构与土壤侵蚀空间格局分析

利用3S技术和景观生态学原理,以小流域为单元对秦皇岛市土地利用结构和土壤侵蚀等级类型进行空间分析,得出了不同土地利用结构所占面积和不同土壤侵蚀类型所占面积及分布小流域,并详细分析了秦皇岛市土壤侵蚀的主要影响因子和不同土地利用结构侵蚀现状。     

附加回流的生物接触氧化工艺净化滇池大清河水质的示范工程研究

针对滇池流域污染最为严重的大清河,采用附加回流生物接触氧化工艺（IBCOP）开展河道水体的旁路处理示范工程研究。IBCOP示范工程的设计规模为1 000 m³/d,HRT为4.75 h,在2007年11月至2008年4月冬旱季期间,根据气候和进水水质条件调节回流比,示范工程运行了3种工况。研究结果表明：示范工程对COD和NH⁺₄-N具有较高的去除效果,平均去除率为46.8%和48.8%,高回流比有利于去除NH⁺₄-N;受到低温、低碳源、高进水DO和生物膜生长不佳等因素影响,示范工程对TN去除效果较低,平均去除率为10.2%,调节回流比不能显著改善碳源不足的情况;水绵的吸收和底泥的沉积是示范工程除磷的主要机理,TP平均去除率为17.9%,低TP浓度进水、生物膜的脱落以及高回流比不利于除磷。