Hydrologic Landscape Characterization for the Pacific Northwest,USA

We update the Wigington et al. (2013) hydrologic landscape (HL) approach to make it more broadly applicable and apply the revised approach to the Pacific Northwest (PNW; i.e., Oregon, Washington, and Idaho). Specific changes incorporated are the use of assessment units based on National Hydrography Dataset Plus V2 catchments, a modified snowmelt model validated over a broader area, an aquifer permeability index that does not require preexisting aquifer permeability maps, and aquifer and soil permeability classes based on uniform criteria. Comparison of Oregon results for the revised and original approaches found fewer and larger assessment units, loss of summer seasonality, and changes in rankings and proportions of aquifer and soil permeability classes. Differences could be explained by three factors: an increased assessment unit size, a reduced number of permeability classes, and use of smaller cutoff values for the permeability classes. The distributions of the revised HLs in five groups of Oregon rivers were similar to the original HLs but less variable. The improvements reported here should allow the revised HL approach to be applied more often in situations requiring hydrologic classification and allow greater confidence in results. We also apply the map results to the development of hydrologic landscape regions.     

Hydrologic Effects of Surface Coal Mining in Appalachia (U.S.)

Surface coal mining operations alter landscapes of the Appalachian Mountains, United States, by replacing bedrock with mine spoil, altering topography, removing native vegetation, and constructing mine soils with hydrologic properties that differ from those of native soils. Research has demonstrated hydrologic effects of mining and reclamation on Appalachian landscapes include increased peakflows at newly mined and reclaimed watersheds in response to strong storm events, increased subsurface void space, and increased base flows. We review these investigations with a focus on identifying changes to hydrologic flow paths caused by surface mining for coal in the Appalachian Mountains. We introduce two conceptual control points that govern hydrologic flow paths on mined lands, including the soil surface that partitions infiltration vs. surface runoff and a potential subsurface zone that partitions subsurface storm flow vs. deeper percolation. Investigations to improve knowledge of hydrologic pathways on reclaimed Appalachian mine sites are needed to identify effects of mining on hydrologic processes, aid development of reclamation methods to reduce hydrologic impacts, and direct environmental mitigation and public policy.     

Applications of Turbidity Monitoring to Forest Management in California

Many California streams have been adversely affected by sedimentation caused by historic and current land uses, including timber harvesting. The impacts of timber harvesting and logging transportation systems on erosion and sediment delivery can be directly measured, modeled, or inferred from water quality measurements. California regulatory agencies, researchers, and land owners have adopted turbidity monitoring to determine effects of forest management practices on suspended sediment loads and water quality at watershed, project, and site scales. Watershed-scale trends in sediment discharge and responses to current forest practices may be estimated from data collected at automated sampling stations that measure turbidity, stream flow, suspended sediment concentrations, and other water quality parameters. Future results from these studies will provide a basis for assessing the effectiveness of modern forest practice regulations in protecting water quality. At the project scale, manual sampling of water column turbidity during high stream flow events within and downstream from active timber harvest plans can identify emerging sediment sources. Remedial actions can then be taken by managers to prevent or mitigate water quality impacts. At the site scale, manual turbidity sampling during storms or high stream flow events at sites located upstream and downstream from new, upgraded, or decommissioned stream crossings has proven to be a valuable way to determine whether measures taken to prevent post-construction erosion and sediment production are effective. Turbidity monitoring at the project and site scales is therefore an important tool for adaptive management. Uncertainty regarding the effects of current forest practices must be resolved through watershed-scale experiments. In the short term, this uncertainty will stimulate increased use of project and site-scale monitoring.     

Streamflow Responses to Climate Change: Analysis of Hydrologic Indicators in a New York City Water Supply Watershed

Recent works have indicated that climate change in the northeastern United States is already being observed in the form of shorter winters, higher annual average air temperature, and more frequent extreme heat and precipitation events. These changes could have profound effects on aquatic ecosystems, and the implications of such changes are less understood. The objective of this study was to examine how future changes in precipitation and temperature translate into changes in streamflow using a physically based semidistributed model, and subsequently how changes in streamflow could potentially impact stream ecology. Streamflow parameters were examined in a New York City water supply watershed for changes from model‐simulated baseline conditions to future climate scenarios (2081‐2100) for ecologically relevant factors of streamflow using the Indicators of Hydrologic Alterations tool. Results indicate that earlier snowmelt and reduced snowpack advance the timing and increase the magnitude of discharge in the winter and early spring (November‐March) and greatly decrease monthly streamflow later in the spring in April. Both the rise and fall rates of the hydrograph will increase resulting in increased flashiness and flow reversals primarily due to increased pulses during winter seasons. These shifts in timing of peak flows, changes in seasonal flow regimes, and changes in the magnitudes of low flow can all influence aquatic organisms and have the potential to impact stream ecology.     

Impacts of 21st‐Century Climate Change on Hydrologic Extremes in the Pacific Northwest Region of North America

Climate change projections for the Pacific Northwest (PNW) region of North America include warmer temperatures (T), reduced precipitation (P) in summer months, and increased P during all other seasons. Using a physically based hydrologic model and an ensemble of statistically downscaled global climate model scenarios produced by the Columbia Basin Climate Change Scenarios Project, we examine the nature of changing hydrologic extremes (floods and low flows) under natural conditions for about 300 river locations in the PNW. The combination of warming, and shifts in seasonal P regimes, results in increased flooding and more intense low flows for most of the basins in the PNW. Flood responses depend on average midwinter T and basin type. Mixed rain and snow basins, with average winter temperatures near freezing, typically show the largest increases in flood risk because of the combined effects of warming (increasing contributing basin area) and more winter P. Decreases in low flows are driven by loss of snowpack, drier summers, and increasing evapotranspiration in the simulations. Energy‐limited basins on the west side of the Cascades show the strongest declines in low flows, whereas more arid, water‐limited basins on the east side of the Cascades show smaller reductions in low flows. A fine‐scale analysis of hydrologic extremes over the Olympic Peninsula echoes the results for the larger rivers discussed above, but provides additional detail about topographic gradients.     

Delving into the “Institutional Black Box”: Revealing the Attributes of Sustainable Urban Water Management Regimes1

van de Meene, Susan J. and Rebekah R. Brown, 2009. Delving into the “Institutional Black Box”: Revealing the Attributes of Sustainable Urban Water Management Regimes. Journal of the American Water Resources Association (JAWRA) 45(6):1448‐1464. Abstract: This paper is based on the proposition that the transition to sustainable urban water management has been hampered by the lack of insight into attributes of a sustainable urban water regime. Significant progress has been made in developing technical solutions to advance urban water practice, however it is the co‐evolution of the socio‐institutional and technical systems that enable a system‐wide transition. A systematic analysis of 81 empirical studies across a range of practice areas was undertaken to construct a schema of the sustainable urban water regime attributes. Attributes were identified and analyzed using a framework of nested management regime spheres: the administrative and regulatory system, inter‐organizational, intra‐organizational, and human resources spheres. The regime is likely to involve significant stakeholder involvement, collaborative inter‐organizational relationships, flexible and adaptive organizational cultures, and motivated and engaging employees. Comparison of the constructed sustainable and traditional regime attributes reveals that to realize sustainable urban water management in practice a substantial shift in governance is required. This difference emphasizes the critical need for explicitly supported strategies targeted at developing each management regime sphere to further enable change toward sustainable urban water management.     

Fuzzy综合评判在森林水文效应研究中的应用

本文应用多层次、二型Fuzzy综台评判方法,对祁连山水源涵养林区的青海云杉林、祁连圆柏林、灌木林和牧坡草地4个不同植被类型进行了森林水文效应的多因子综合评判。结果表明:青海云杉林是该林区涵养水源效应最佳的林型,祁连圆柏林和灌木林次之,牧坡草地不仅蓄水能力差,且有水土流失发生;并提出了各植被类型合理经营的对策,为祁连山水源涵养林的保护、发展和综合利用提供科学依据。     

山地自然资源的环境特征与可持续开发对策

本文通过分析山地自然资源环境的基本特征,从开发模式、利用规模和适当的开发场所三方面论述了山地自然资源可持续开发对策,并指出了在山地自然资源可持续开发过程中应重点注意的问题。     

浅谈天然气采输过程环境保护管理

环境管理作为HSE管理的重要内容之一,与安全管理同样重要。天然气采输工程包含大量的工艺作业,若环境风险防控措施不到位,极易引发严重的环境污染事故。文章分析了天然气采输过程所涉及的环境保护问题,并对目前环境管理现状进行分析,识别天然气采输过程中的环境风险,分别从技术措施和组织管理措施两个方面提出了环境管理建议,为天然气采输过程的环境保护工作提供指导性依据。     

Inventory of ocean monitoring in the Southern California Bight

Monitoring of the ocean environment in southern California, USA, has been conducted by a diverse array of public and private organizations with different motivations, working on a variety of spatial and temporal scales. To create a basis from which to integrate information from these diverse programs, we conducted an inventory of ocean monitoring activities in the Southern California Bight to address the following questions: (1) How much money is being expended annually on marine monitoring programs? (2) Which organizations are conducting the most monitoring? (3) How are resources allocated among the different types of monitoring programs? This inventory focused on programs existing, or those expected to be in existence, for at least 10 years and that were active at any time between 1994 and 1997. For each program identified for inclusion in this study, information was collected on the number of sites, sampling intensity, parameters measured, and methods used. Levels of effort were translated into cost estimates based upon a market survey of local consulting firms. One hundred fourteen marine monitoring programs, conducted by 65 organizations and costing US $31 million annually, were identified. Most of the effort (81 programs, 65% of samples, 70% of costs) was expended by ocean dischargers as part of their compliance with National Pollutant Discharge Elimination System (NPDES) permit requirements. Federal programs (11 programs, 25% of samples, 10% of total expenditures) expended more than state or local government programs. More than one quarter of monitoring expenditures were conducted to measure concentrations and mass of effluent inputs to the ocean. The largest effort expended on receiving water monitoring was for measuring bacteria, followed by sediments, fish/shellfish, water quality, and intertidal habitats. The large level of expenditures by individual agencies has presented opportunities for integrating small, site-specific ocean monitoring programs into regional- and national-scale monitoring and assessment programs.     

Critical Steps for Continuing Advancement of Satellite Rainfall Applications for Surface Hydrology in the Nile River Basin1

Gebremichael, Mekonnen, Emmanouil N. Anagnostou, and Menberu M. Bitew, 2010. Critical Steps for Continuing Advancement of Satellite Rainfall Applications for Surface Hydrology in the Nile River Basin. Journal of the American Water Resources Association (JAWRA) 46(2):361-366. DOI: 10.1111/j.1752-1688.2010.00428.x. Abstract: Given the increasingly higher resolution and data accessibility, satellite precipitation products could be useful for hydrological application in the Nile River Basin, which is characterized by lack of reasonably dense hydrological in situ sensors and lack of access to the existing dataset. However, in the absence of both extreme caution and research results for the Nile basin, the satellite rainfall (SR) products may not be used, or may even be used erroneously. We identify two steps that are critical to enhance the value of SR products for hydrological applications in the Nile basin. The first step is to establish representative validation sites in the Nile basin. The validation site will help to quantify the errors in the different kinds of SR products, which will be used to select the best products for the Nile basin, include the errors in decision making, and design strategies to minimize the errors. Using rainfall measurements collected from the unprecedented high-density rain gauge network over a small region within the Nile basin, we indicate that SR estimates could be subject to significant errors, and quantification of estimation errors by way of establishing validation sites is critically important in order to use the SR products. The second step is to identify the degree of hydrologic model complexity required to obtain more accurate hydrologic simulation results for the Nile basin when using SR products as input. The level of model complexity may depend on basin size and SR algorithm, and further research is needed to spell out this dependence for the Nile basin.     

高含硫天然气钻探工程环境监理要点探讨

对高含硫天然气钻探工程的主要环境影响进行了分析,针对大气环境、水环境、声环境、固体废弃物、生态环境及水土流失、环境风险等环境要素,对其环境监理要点进行了探讨.     

Development and Comparison of Multiple Regression Models to Predict Bankfull Channel Dimensions for Use in Hydrologic Models

Channel dimensions are important input variables for many hydrologic models. As measurements of channel geometry are not available in most watersheds, they are often predicted using bankfull hydraulic geometry relationships. This study aims at improving existing equations that relate bankfull width, depth, and cross‐sectional area to drainage area (DA) without limiting their use to well‐gauged watersheds. We included seven additional variables in the equations that can be derived from data that are generally required by hydrologic models anyway and conducted several multiple regression analyses to identify the ideal combination of additional variables for nationwide and regional models for each Physiographic Division of the United States (U.S.). Results indicate that including the additional variables in the regression equations generally improves predictions considerably. The selection of relevant variables varies by Physiographic Division, but average annual precipitation (PCP) and temperature (TMP) were generally found to improve the models the most. Therefore, we recommend using regression equations with three independent variables (DA, PCP, and TMP) to predict bankfull channel dimensions for hydrologic models. Furthermore, we recommend using the regional equations for watersheds within regions from which data were used for model development, whereas in all other parts of the U.S. and the rest of the world, the nationwide equations should be given preference.     

天然气净化厂放空废气对环境的影响及控制措施

天然气净化厂除正常生产有工艺废气排放外,传统装置检修开停产过程、供电或设备异常情况下,会有大量酸气、原料气通过放空火炬燃烧后排放。文章主要分析了天然气净化装置放空废气排放情况及其对周边环境的影响,阐述了异常放空、检修开停产过程原料气和酸气放空的控制措施及其环境效益。     

Costs of Arsenic Treatment for Potable Water in California and Comparison to U.S. Environmental Protection Agency Affordability Metrics1

Hilkert Colby, Elizabeth J., Thomas M. Young, Peter G. Green, and Jeannie L. Darby, 2010. Costs of Arsenic Treatment for Potable Water in California and Comparison to U.S. Environmental Protection Agency Affordability Metrics. Journal of the American Water Resources Association (JAWRA) 46(6):1238–1254. DOI: 10.1111/j.1752-1688.2010.00488.x Abstract: The United States (U.S.) federal standard for arsenic in potable water systems is only the second water quality standard in which the U.S. Environmental Protection Agency (USEPA) administrator used “discretionary authority to establish a less stringent standard” based on the results of cost-benefit analyses. Based on the findings that a “standard of 3 μg/l would be feasible but not justified,” the revised maximum contaminant level (MCL) lowered the allowable arsenic concentration from 50 to 10 μg/l in 2002. In 2009, approximately 145 systems in California were out of compliance. The objectives were to gather performance and cost data from arsenic treatment systems in California to compare with data from the USEPA demonstration sites as well as with the USEPA affordability metrics for drinking water. The median cost of compliance with the revised arsenic MCL for the 36 surveyed systems was $1.95/1,000 gallons (2008 dollars), which is 69% of the average cost of delivered tap water in the U.S. in 2008 ($2.81/1,000 gallons). Additionally, 22% of the surveyed systems in California paid more than the maximum predicted cost of compliance with the revised arsenic MCL ($5.05/1,000 gallons). The largest variation in cost was seen in the systems that treated <500 gpm. For the systems utilizing adsorption, systems obtained between 20 and 80% of the expected bed volumes prior to breakthrough, indicating the need for better prediction of performance.     

自然资源利用权的双重物权属性及环境保护价值

自然资源利用权从产生的途径上看应属于特许物权,从内容和功能上看应属于准用益物权,两种物权属性并不相互排斥。自然资源利用权的双重物权属性符合环境保护的价值取向和价值选择。     

天然气勘探开发项目综合环境影响评价指标体系研究

针对目前天然气勘探开发项目环境影响评价不够系统的局限性,运用系统的思想观点和思维方法提出了天然气勘探开发项目综合环境影响评价指标体系.该评价体系把综合环境影响评价分为政策法规环境影响、自然生态环境影响、资源能源环境影响、经济环境影响、社会环境影响和科技环境影响等六大环境影响进行评价.借鉴环境影响评价的相关研究成果,分别为上述六大环境影响评价设计了具体的评价因子和评价指标.     

川渝地区天然气钻井作业环境影响及防治措施

针对天然气钻井作业特点、川渝地区土地资源与生态环境条件,在分析天然气钻井作业对川渝地区社会环境与生态环境影响及环境污染的基础上,提出了目前川渝地区天然气钻井作业存在的环境问题,并根据这些环境问题分别在钻井不同作业过程中给出了环境防治措施。