DROUGHT PLANNING: A PROCESS FOR STATE GOVERNMENT1

ABSTRACT: Drought has been a prevalent feature of the American landscape during the latter part of the 1980s, producing serious socioeconomic and environmental consequences. These recent experiences with drought have renewed concern about the inadequacy of federal and state contingency planning efforts and the lack of coordination for assessment and response efforts between these levels of government. This paper presents the results of research aimed at facilitating the preparation of drought contingency plans by state government in conjunction with a state's overall water management planning activity. The ten-step drought plan development process reported is intended to improve mitigation efforts through more timely, effective, and efficient assessment and response activities. Officials in appropriate state agencies should examine the proposed framework and alter it to best address drought-related concerns, adding or deleting elements as necessary.     

MFAM模型在河流水质污染模拟及预测中的应用

文中以时间序列分析为基础，介绍了均值生成函数这一崭新概念，并且经成份因子提取分析推导建立了模拟序列的数字模型（简记为MFAM），经对黄河下游花园口断面的1988-1989年实测水质污染指标溶解氧（DO），氨氧，化学耗氧量（COD），五日生化需氧量（BOD5）等序列模拟，结果表明MFAM模型能较好地模拟河流水质污染指标的变化趋势，拟合平均误差只有5.2-6.4%，MFAM模型应用于预测1990-1991年水质污染指标变化，结果表明预测精度达85%以上，文中最后得出结论：MFAM模型应用于河流污染模拟和预测，是完全可行且十分方便。     

Control of upland bank erosion through tidal marsh construction on restored shores: Application in the maryland portion of Chesapeake Bay

During the period of 1972 through 1993, Environmental Concern Inc. (EC) and its recent (1989) affiliate Environmental Construction Company (ECC) have completed 216 marsh construction projects to control upland bank erosion in tributaries of the Maryland portion of Chesapeake Bay. Of these projects, 26 have involved marsh construction on unaltered existing shores and 190 have utilized marsh construction on shores that have been restored to former increased elevations through shoreline filling and grading. This paper describes the latter restoration technique. Throughout the 21-year period of applying the technique for long-term upland bank erosion control, refinements to the design standards and criteria for site suitability have been made so as to optimize its successful application. As a result of this experience, a reliable bioengineering restoration technique has evolved to control upland bank erosion. This paper describes the details of this successful technique through a review of: (1) its objectives and benefits, (2) suitability of sites for its application, (3) the design of its shore restoration, (4) its construction, (5) its maintenance, and (6) comparison of its cost with those of structural techniques for bank erosion control. Although the technique has only been applied in the Maryland portions of Chesapeake Bay, its applicability should, with modifications, be broadly applicable to all water bodies.     

SUBALPINE,COLD CLIMATE,STORMWATER TREATMENT WITH A CONSTRUCTED SURFACE FLOW WETLAND1

The Tahoe City Wetland Treatment System (TCWTS) was constructed in 1997 to treat stormwater runoff from 23 ha of commercial, highway, and residential land use in the Lake Tahoe Basin. This subalpine, constructed, surface flow wetland treatment system consists of two cells in series, with a design water surface area of about 0.6 ha. Water quality monitoring from October 2002 through September 2003 was conducted with autosamplers at the inflow and outflow sites during 24 sampling events, with a median duration of 53 hours, representing 42 percent of total inflow to this wetland during the year. Monitoring data indicate an improvement of 49 percent or greater in effluent concentrations of dissolved phosphorus, nitrate, orthophosphorus, and total suspended solids. On average, event mean concentrations of total phosphorus were reduced from a median 279 μg/l at the inflow to 94 μg/l at the outflow. Event mean concentrations of total nitrogen were reduced from a median 1,599 μg/l at the inflow to 810 μg/l at the outflow. Net nutrient retention for the sampling period was estimated at 3 g phosphorus (P)/m²/y and 13 g nitrogen (N)/m²/y. Almost 4,000 kg of suspended sediment was captured by this wetland system during the year.     

ASSESSMENT OF POSSIBLE IMPACTS OF CLIMATE CHANGE IN AN URBAN CATCHMENT1

ABSTRACT: Stationarity of rainfall statistical parameters is a fundamental assumption in hydraulic infrastructure design that may not be valid in an era of changing climate. This study develops a framework for examining the potential impacts of future increases in short duration rainfall intensity on urban infrastructure and natural ecosystems of small watersheds and demonstrates this approach for the Mission/Wagg Creek watershed in British Columbia, Canada. Nonstationarities in rainfall records are first analyzed with linear regression analysis, and the detected trends are extrapolated to build potential future rainfall scenarios. The Storm Water Management Model (SWMM) is used to analyze the effects of increased rainfall intensity on design peak flows and to assess future drainage infrastructure capacity according to the derived scenarios. While the framework provided herein may be modified for cases in which more complex distributions for rainfall intensity are needed and more sophisticated stormwater management models are available, linear regressions and SWMM are commonly used in practice and are applicable for the Mission/Wagg Creek watershed. Potential future impacts on stream health are assessed using methods based on equivalent total impervious area. In terms of impacts on the drainage infrastructure, the results of this study indicate that increases in short duration rainfall intensity may be expected in the future but that they would not create severe impacts in the Mission/Wagg Creek system. The equivalent levels of imperviousness, however, suggest that the impacts on stream health could be far more damaging.     

Waste reduction through variable charging programs: its sustainability and contributing factors

 In this study, we analyzed the sustainability and determinant factors of waste reduction through variable charging schemes. We drew three main conclusions from the study. (1) Waste reduction was achieved by variable charging and was sustained over an average of at least 10 years. The results regarding the sustainability of the price effect were inconclusive. (2) The main factors contributing to the combustible waste reduction achieved through variable charging were two-tier pricing and the price of waste bags. The effect of two-tier pricing programs was positive. (3) Waste paper recycling and variable charging reinforce each other to promote waste reduction. Received: September 3, 2001 / Accepted: January 13, 2002     

热带气旋的短期气候预报检验

用非线性预报的方法，作西太平洋、南海、以及登陆我国、登陆广东热带气旋的短期气候预测，用逐日气压场作登陆广东热带气旋的时段和地段以及南海海面带气旋出现的时间的气候预测。对近3年的热带气候预报进行检验，效果较满意。     

洞庭湖区域环境整治规划及措施

随着工、农业的发展,洞庭湖区域的环境污染日趋严重。本文较详细地研究了洞庭湖区域的环境整治规划,在各环境要素的规划方面进行了探讨。     

四川盆地森林覆盖率自然影响因素分析

本文对四川盆地森林覆盖率的影响因素进行逐步回归分析,结果表明影响森林覆盖率的自然因素是综合的,它包括气候、地貌、土壤等自然条件。其中以7月降水量、地形崎岖度、山地比例、酸性紫色土比例及土地垦殖系数等作为决定四川森林覆盖率变化的最重要因素,这5个因素即可解释盆地森林覆盖率80%以上的变化。     

The impact of global warming on winter tourism and skiing: a regionalised model for Austrian snow conditions

Possible climate change will modify snow-cover depth and change the characteristics of winter tourism and skiing districts. Our model describes seasonal snow-cover depth related to altitude in six Alpine climate regions as the best fit of all snow stations. Data cover 30 winter seasons (November to April values) from 1965 to 1995. We modified the data according to a scenario of temperature and precipitation change (2 °C warming, no precipitation change) and achieve a new simulated snow-cover depth. The indicators MARP (mean altitude of resident population) and MASPSL (mean altitude of starting point of ski lifts) serve as references for “critical altitudes” of Austrian districts. A warming implies a reduction of snow in all districts, but the loss is overproportional in lower altitudes. The direction of economic impacts is clear – income losses and adaptation costs – but magnitude and time frames remain uncertain. Received: 24 February 1999 · Accepted: 15 May 1999