The dilemma of flood control in the United States

In spite of increasing annual expenditures for flood control, losses from flooding continue to rise in the United States. This seeming contradiction arises from overdependence on federally supported structural solutions to flood problems. Nonstructural controls are initiated reluctantly at local levels of government because of constitutional questions, restrictions of local tax bases, lack of federal subsidies for nonstructural solutions, and the high costs of delineating flood hazard areas. The success of the National Flood Insurance Program is doubtful since only about five percent of the flood-prone communities in the United States have qualified for the regular program. Future reduction of flood losses is dependent upon increasing popular awareness of flood hazards and altering federal subsidy policies to reduce the impact of local land-use regulations.     

Evaluation of Flood and Landslide Risk to the Population of Italy

We have compiled a database of floods and landslides that occurred in Italy between AD 1279 and 2002 and caused deaths, missing persons, injuries, and homelessness. Analysis of the database indicates that more than 50,593 people died, went missing, or were injured in 2580 flood and landslide events. Harmful events were inventoried in 26.3% of the 8103 Italian municipalities. Fatal events were most frequent in the Alpine regions of northern Italy and were caused by both floods and landslides. In southern Italy, landslides were the principal agents of fatalities and were most numerous in the Campania region. Casualties were most frequent in the autumn. Fast-moving landslides, including rock falls, rockslides, rock avalanches, and debris flows, caused the largest number of deaths. In order to assess the overall risk posed by these processes, we merged the historical catalogs and identified 2682 “hydrogeomorphological” events that triggered single or multiple landslides and floods. We estimated individual risk through the calculation of mortality rates for both floods and landslides and compared these rates to the death rates for other natural, medical, and human-induced hazards in Italy. We used the frequency distribution of events with fatalities to ascertain the magnitude and frequency of the societal risks posed by floods and landslides. We quantified these risks in a Bayesian model that describes the probabilities of fatal flood and landslide events in Italy.     

Water quality standards: Everglades National Park

Water quality criteria were developed for delivery waters to Everglades National Park. The park receives a minimum of 12.34 m³/sec (315,000 acre-ft/yr) of water from controlled sources external to its boundary. These waters often originate from areas that are or potentially are impacted from urban and agricultural developments. When, in 1970, the U.S. Congress guaranteed minimum water deliveries to Everglades National Park, it also required that these waters be of good quality.The Everglades National Park water quality data base was analyzed from 1970 to 1978 at both in-park and water delivery sites to determine the current level of delivery water quality and to select representative delivery sites. It was found that current delivery water quality was sufficiently high to be adopted as criteria against which future water quality could be compared. From the delivery sites S-12C and L-67A all data were combined from 1970–1978 for 36 parameters including macronutrients, heavy metals, and field parameters such as DO, pH, and specific conductance. Mean concentrations and upper limits were computed and tabulated for comparison during future monitoring programs. These criteria were subsequently adopted through a joint memorandum of agreement between the U.S. Army Corps of Engineers, South Florida Water Management District and the U.S. National Park Service.     

《水污染防治行动计划》实施的宏观经济影响分析

基于全产业链视角,本文采用投入产出模型定量模拟了《水污染防治行动计划》(以下简称《水十条》)项目实施的社会经济影响.结果表明,《水十条》的实施:①起到了刺激经济发展、促进社会就业的作用,将拉动我国GDP 累计增加56 964 亿元,其中直接贡献占13%,间接贡献占87%;累计增加非农就业岗位398 万人,其中直接贡献占29%,间接贡献占71%.②将拉动环保装备制造、建筑安装、环保技术服务等相关行业的发展,同时通过产业链关联间接带动农林牧渔业、交通运输及仓储业、批发和零售业、专用设备制造业等行业的发展.③在我国环境保护投资仍然严重不足的情况下,加大环保投资有利于带动节能环保产业的发展,促进我国经济战略转型.     

EFFECTS OF POTENTIAL WATER CONSERVATION EFFORTS IN EAST TENNESSEE1

ABSTRACT: The importance of water conservation was emphasized by a proposed National Water Policy which was established during the previous Carter Administration. This policy stressed water conservation on a national scale. Such a policy sought to apply one program to all water resources problems. Before implementation of this or another such policy, consideration must be given to those vast areas of the country which in reality do not have a shortage of water. One of these areas is the French-Broad River basin in Tennessee. This report was formulated in an effort to describe both the positive and negative effects of water policies which would bring about either a 10 percent or 30 percent reduction in water usage in this basically water rich area. The parameters used in the evaluation included selected economic, sociological, legal, and environmental impacts.     

Bacterial water quality: Springs and streams in the Great Smoky Mountains National Park

Water samples from streams and springs in the Great Smoky Mountains National Park were analyzed for fecal coliform, fecal streptococcus, and total coliform bacteria. Levels of bacteria were found to be highly variable but related to elevation, time of year, type of water source, and water level of the streams. Visitors did not seem to be major contributors to bacterial contamination. Levels of fecal coliform and total coliform in most water samples were unsuitable for drinking without treatment. Tennessee state standards for body contact recreation (swimming and wading) were exceeded in a few samples but none from streams suitable for swimming. As a result of these findings, park managers increased efforts to inform visitors of the need to treat drinking water and removed improvements at backcountry springs which tended to give the springs the image of safe, maintained water sources.     

秦皇岛市“创模”对策研究及效益分析

介绍了秦皇岛市创建国家环境保护模范城市的意义,重点阐述了完成创模任务的主要对策,包括:构建以旅游业为中心、特色产业互融互促的现代产业体系;加快城乡一体化建设;提升城镇发展质量和水平;加强重大基础设施建设;积极推广清洁能源,深入开展工程节能;积极推进循环经济发展等。秦皇岛市创建国家环境保护模范城市,将会在环境、经济和社会三方面产生明显的综合效益。     

Status report on flood warning systems in the United States

One of the major changes in flash-flood mitigation in the past decade is the number of communities that have implemented warning systems. The authors conducted a survey of 18 early-warning systems in the United States developed by communities or regions to provide protection against flash floods or dam failures. Problems revealed by the study included the following: equipment malfunctions, inadequate maintenance funding, inconsistent levels of protection and expenditure, inconsistent levels of expectations and formalization, varying levels of local commitment to the systems, underemphasis on response capability, and a tendency to over-rely on warning systems. The study also revealed some unanticipated benefits experienced by the survey communities: the warning systems serve as valuable data collection tools, a great deal of interagency cooperation has been demonstrated, and warning systems offer increased alternatives to structural modification projects. The interjurisdictional nature of drainage basins, the evolving roles of the various federal agencies involved in flood mitigation, and the lack of governmental standards of operations for flood warning systems are issues that must be considered as communities make decisions regarding the adoption of warning systems. The record on these systems is too short for a precise assessment of how successful they are; however, results of the study indicate that if the goal of reducing loss of life and property from flooding is to be achieved, warning systems must be only one part of a comprehensive flood loss reduction program.     

Model simulations of dissolved oxygen characteristics of Minnesota lakes: Past and future

A deterministic, one-dimensional, unsteady numerical model has been developed, tested, and applied to simulate mean daily dissolved oxygen (DO) characteristics in 27 lake classes in the state of Minnesota. Reaeration and photosynthesis are the oxygen sources, while respiration, sedimentary, and biochemical water column oxygen demand are the sinks of oxygen in the model. The lake classes are differentiated by surface area (A _s), maximum depth (H _max), and trophic status expressed as Secchi depth (Z _s). Because lake stratification is most important to lake oxygen dynamics, simulated DO characteristics are plotted in terms of a stratification parameterA _s/H _max ^0.25 and Secchi depthZ _s. Simulations provide DO profiles on a daily time scale. Specific DO characteristics of ecological and environmental interest are epilimnetic DO, hypolimnetic DO, DO gradient from surface to bottom, and DO minima and maxima. Specific results are as follows: Simulated mean daily and weekly DO values in the epilimnion of all lakes for both past and future climate scenarios are near saturation over the summer season. Hypolimnetic DO values depend strongly on lake morphometry, trophic status, and time throughout the summer season. Future climate conditions are specified as the historical records from 1955 to 1979, adjusted (monthly) by the 2 × CO₂ GISS model output to account for doubling of atmospheric CO₂. With this climate change, weekly averaged epilimnetic DO is projected to drop by less than 2 mg/liter, and will remain above 7 mg/liter throughout the open water season. The hypolimnetic DO reductions after climate change are on the order of 2–8 mg/liter. Periods of anoxia are longer by as much as 80 days. Those changes would alter water quality dynamics in lakes and have a profound effect on lake ecosystems including indigenous fishes. The results presented are useful for evaluating environmental management options.