STREAMFLOW TRENDS IN WISCONSIN'S DRIFTLESS AREA1

ABSTRACT: Trends in streamflow characteristics were analyzed for streams in southwestern Wisconsin's Driftless Area by using data at selected gaging stations. The analyses indicate that annual low flows have increased significantly, whereas annual flood peaks have decreased. The same trends were not observed for forested areas of northern Wisconsin. Streamflow trends for other streams in southeastern Wisconsin draining predominantly agricultural land were similar to trends for Driftless Area streams for annual low flows. The causes for the trends are not well understood nor are the effects. Trends in annual precipitation do not explain the observed trends in streamflow. Other studies have found that erosion rates decreased significantly in the Driftless Area, and have attributed this reduction to a change of agricultural practices, which increase infiltration, decrease flood peaks, and increase low flows.     

COMPARISON OF PARAMETRIC TAIL ESTIMATORS FOR LOW‐FLOW FREQUENCY ANALYSIS1

ABSTRACT: In recent years, several approaches to hydrologic frequency analysis have been proposed that enable one to direct attention to that portion of an overall probability distribution that is of greatest interest. The majority of the studies have focused on the upper tail of a distribution for flood analyses, though the same ideas can be applied to low flows. This paper presents an evaluation of the performances of five different estimation methods that place an emphasis on fitting the lower tail of the lognormal distribution for estimation of the ten‐year low‐flow quantile. The methods compared include distributional truncation, MLE treatment of censored data, partial probability weighted moments, LL‐moments, and expected moments. It is concluded that while there are some differences among the alternative methods in terms of their biases and root mean square errors, no one method consistently performs better than the others, particularly with recognition that the underlying population distribution is unknown. Therefore, it seems perfectly legitimate to make a selection of a method on the basis other criteria, such as ease of use. It is also shown in this paper that the five alternative methods can perform about as well as, if not better than, an estimation strategy involving fitting the complete lognormal distribution using L‐moments.     

End-of-life flows of multiple cycle consumer products

Explicit expressions for the end-of-life flows (EOL) of single and multiple cycle products (MCPs) are presented, including deterministic and stochastic EOL exit. The expressions are given in terms of the physical parameters (maximum lifetime, T, annual cycling frequency, f, number of cycles, N, and early discard or usage loss). EOL flows are also obtained for hi-tech products, which are rapidly renewed and thus may not attain steady state (e.g. electronic products, passenger cars). A ten-step recursive procedure for obtaining the dynamic EOL flow evolution is proposed. Applications of the EOL expressions and the ten-step procedure are given for electric household appliances, industrial machinery, tyres, vehicles and buildings, both for deterministic and stochastic EOL exit, (normal, Weibull and uniform exit distributions). The effect of the physical parameters and the stochastic characteristics on the EOL flow is investigated in the examples: it is shown that the EOL flow profile is determined primarily by the early discard dynamics; it also depends strongly on longevity and cycling frequency: higher lifetime or early discard/loss imply lower dynamic and steady state EOL flows. The stochastic exit shapes the overall EOL dynamic profile: Under symmetric EOL exit distribution, as the variance of the distribution increases (uniform to normal to deterministic) the initial EOL flow rise becomes steeper but the steady state or maximum EOL flow level is lower. The steepest EOL flow profile, featuring the highest steady state or maximum level, as well, corresponds to skew, earlier shifted EOL exit (e.g. Weibull). Since the EOL flow of returned products consists the sink of the reuse/remanufacturing cycle (sink to recycle) the results may be used in closed loop product lifecycle management operations for scheduling and sizing reverse manufacturing and for planning recycle logistics. Decoupling and quantification of both the full age EOL and of the early discard flows is useful, the latter being the target of enacted legislation aiming at increasing reuse.     

The contemporary Oceania zinc cycle: one-year stocks and flows

The material flow approach provides a framework from which to address resource management and estimate gross environmental impacts, both spatially and temporally. In this article, the major flows of zinc in Oceania over its entire life-cycle are examined; these include production (mining, milling, and refining), fabrication and manufacturing of semi- and finished products, use, and the waste management system. Comprehensive mass balances were applied to determine the zinc flows, including the quantities of zinc entering stocks in waste and in-use reservoirs. The Oceania cycle shows that substantial amounts of zinc (about 1120Gg/year) are mined on the continent. The total flow of zinc in finished products entering the use stage is about 8.6kg/(capita.year), substantially exceeding the zinc flow in discarded products. This difference, about 7.2kgZn/(capita.year) on average, is added to the in-use reservoir, largely for galvanizing applications in domestic construction and transportation. Less than 60% of all discarded zinc entering the waste management system is recycled. Much of the remaining discarded zinc is diluted into other waste streams, where recovery and recycling are probably not economically feasible.     

Comparing urban solid waste recycling from the viewpoint of urban metabolism based on physical input-output model: A case of Suzhou in China

Investigating impacts of urban solid waste recycling on urban metabolism contributes to sustainable urban solid waste management and urban sustainability. Using a physical input-output model and scenario analysis, urban metabolism of Suzhou in 2015 is predicted and impacts of four categories of solid waste recycling on urban metabolism are illustrated: scrap tire recycling, food waste recycling, fly ash recycling and sludge recycling. Sludge recycling has positive effects on reducing all material flows. Thus, sludge recycling for biogas is regarded as an accepted method. Moreover, technical levels of scrap tire recycling and food waste recycling should be improved to produce positive effects on reducing more material flows. Fly ash recycling for cement production has negative effects on reducing all material flows except solid wastes. Thus, other fly ash utilization methods should be exploited. In addition, the utilization and treatment of secondary wastes from food waste recycling and sludge recycling should be concerned.     

Precipitation Extremes and Flood Frequency in a Changing Climate in Southeastern Virginia

Despite the advances in climate change modeling, extreme events pose a challenge to develop approaches that are relevant for urban stormwater infrastructure designs and best management practices. The study first investigates the statistical methods applied to the land‐based daily precipitation series acquired from the Global Historical Climatology Network‐Daily (GHCN‐D). Additional analysis was carried out on the simulated Multivariate Adaptive Constructed Analogs (MACA)‐based downscaled daily extreme precipitation of 15 General Circulation Models and Weather Research and Forecasting‐based hourly extreme precipitation of North American Regional Reanalysis to discern the return period of 24‐hr and 48‐hr events. We infer that the GHCN‐D and MACA‐based precipitation reveals increasing trends in annual and seasonal extreme daily precipitation. Both BCC‐CSM1‐1‐m and GFDL‐ESM2M models revealed that the magnitude and frequency of extreme precipitation events are projected to increase between 2016 and 2099. We conclude that the future scenarios show an increase in magnitudes of extreme precipitation up to three times across southeastern Virginia resulting in increased discharge rates at selected gauge locations. The depth‐duration‐frequency curve predicted an increase of 2–3 times in 24‐ and 48‐h precipitation intensity, higher peaks, and indicated an increase of up to 50% in flood magnitude in future scenarios.     

环保投资统计指标体系构建研究——以青岛市为例

文章在总结分析国内外环境保护投资统计指标的基础上,制定了环保投资统计指标构建原则;以青岛市为例,构建环保投资统计指标体系;并使用构建的指标体系统计分析了青岛市2014~2015年环保投资情况。结果表明,2014~2015年青岛市环保投资总额分别为86.30亿元、90.69亿元,其中,污染治理设施投资是环保投资的主要组成部分,占全市环保投资额度的一半以上。环保设施运行维护费用和生态环境保护投资次之,环境管理投资占比最低。     

环境管理体系的保持与维护

探讨企业建立环境管理体系后保持与维护体系应注意的几个问题，介绍了对体系进行持续改进的几种方法和思路。     

旅游流时空演变下的乡村旅游开发研究——基于蓝田县汤峪镇调研数据

我国国内旅游呈快速发展态势。在国内旅游客流中,乡村游、近郊游、短线游、一日游、自驾游、休闲度假游等旅游客流成为主要旅游流,乡村成为重要旅游目的地。以西安市蓝田县汤峪古镇为例,通过实地调查研究,了解在旅游流时空演变下的乡村旅游开发及发展现状,找出面临的问题,从旅游流时空演变机理下的旅游客流、管理流、信息流、资金流、物资流、能量流、文化流、促销流、人才流等方面着手,就管理、开发规划、产品创新、环境与文化保护、市场营销、资金投入、延长产业链、人才培养等方面探讨其可持续发展模式。     

ICP-MS的安装调试和日常维护的注意事项

ICP-MS广泛的用于环境监测系统。本文主要围绕ICP-MS的安装调试、维护保养以及在日常检测工作中应注意的事项展开了讨论。并结合笔者自身经验提出了如何减少故障的办法。