Environmental considerations for levees and floodwalls

Levees and floodwalls are used extensively throughout the United States for flood control. Levee projects often lack ecological, recreational, and aesthetic values, except for incidental fish and wildlife benefits derived from borrow pits and recreational facilities found in some urban settings. In recent years increased environmental concern within construction agencies and greater responsiveness to public opinion have resulted in increasing numbers of levee projects designed, built, and maintained with environmental objectives in mind. This paper reviews environmental concepts successfully employed on levee projects constructed in recent years by the US Army Corps of Engineers. Some of the most innovative concepts are described and illustrated and design considerations are discussed.     

A THEORETICAL FRAMEWORK OF FLOOD INDUCED CHANGES IN URBAN LAND VALUES1

ABSTRACT: By integrating literature from flood hazard research and urban economics a theoretical structure is developed to explain changes in residential land values following flood events. The negative aspects of the flood hazard are shown to be capitalized in the value of the property. It is further suggested that land values (i.e., capitalization) will vary both spatially across the floodplain and temporally depending on the frequency, severity and spatial characteristics of the flood event. Previous work in this area has not addressed the capitalization process explicitly and has not specifically examined the ability of the land market to recover. This may account for the contradictory findings in the published literature.     

IDENTIFICATION OF SOLUTE LOADING SOURCES TO A SURFACE STREAM1

ABSTRACT: A study was performed to identify sources of solute loading to the Dirty Devil River and its major tributaries, in southeastern Utah. A primary goal was to determine the contribution of gypsum dissolution to total dissolved solids concentration, and its potential increase in the future if salinity control measures are instituted. Synoptic field data were collected during the low flow period in October 1983. Data were analyzed using the geochemistry models WATEQF and BALANCE to postulate mineral reactions leading to solute loading. Three known sources of solute loading, involving two different geochemical mechanisms, were clearly discernable. Two additional areas of possible gypsum dissolution were located.     

MANAGEMENT OF INSTREAM FLOWS THROUGH RUNOFF DETENTION AND RETENTION1

ABSTRACT: The use of reservoirs and land treatments to manage streamflow for the maintenance or enhancement of instream flow values is a valid concept. Historically, large reservoirs have been used for flood control and water-supply regulation. Smaller structures have enjoyed widespread use for soil and water conservation in headwater areas. Where reservoir releases can be controlled, it is technically feasible to regulate flows for the enhancement of instream values. However, institutional and political obstacles may preclude the operation of some reservoirs for this purpose. Retention and detention structures and land treatments, implemented for soil and water conservation purposes, have often had favorable effects on the streamflow hydrograph. Decreases in peak flows and increases in low flows have been documented. Design concepts for runoff-control structures are discussed in relation to instream flow management objectives. Hydro-logic simulation is offered as a potential tool for project design and feasibility analysis.     

ALTERNATIVES TO THE USE OF AGRICULTURAL DRAINAGE WELLS1

ABSTRACT: A large number of agricultural drainage wells (ADWs) are located in north-central Iowa. These wells permit sediments, pesticides, nitrate, and bacteria in surface and subsurface drainage water to enter regional aquifers that are currently being used for drinking-water supplies, mostly by rural families and communities. This paper reports some possible alternatives to control the entry of surface and subsurface drainage waters into groundwater systems, and describes a methodology to make comprehensive economic feasibility studies of alternative drainage outlets. The estimated cost of providing main subsurface drains varied from $220 to $960 per hectare. If the use of ADWs was completely eliminated without providing alternative drainage, it is estimated that the average annual loss to the farmers of the area would be at least $270 per hectare in reduced crop yields. Of course, losses would be weather dependent and highly variable. Management practices to reduce the pollutant load in water draining to ADWs are also discussed.     

Population control of exotic rainbow trout in streams of a natural area park

Expansion of the distribution of exotic rainbow trout is thought to be a leading cause for the decline of native brook trout since the 1930s in Great Smoky Mountains National Park, USA. An experimental rehabilitation project was conducted from 1976 to 1981 using backpack electrofish shockers on four remnant brook trout populations sympatric with rainbow trout. The objectives were to evaluate the effectiveness of the technique to remove the exotic rainbow trout, to determine the population responses by native brook trout, and to evaluate the usefulness of the technique for trout management in the park.Rainbow trout populations were greatly reduced in density after up to six years of electrofishing, but were not eradicated. Rainbow trout recruitment, however, was essentially eliminated. Brook trout populations responded by increasing in density (including young-of-the-year), but rates of recovery differed among streams. The maximum observed densities ir each stream occurred at the end of the project.The findings suggest that electrofishing had a major negative impact on the exotic species, which was followed by positive responses from the native species in the second and third order study streams. The technique would probably be less effective in larger (fourth-order) park streams, but as an eradication tool the technique may have its highest potential in small first order streams. Nonetheless, the technique appears useful for population control without causing undue impacts on native aquatic species, although it is labor intensive, and capture efficiency is greatly influenced by fish size and stream morphology. To completely remove the exotic fish from selected streams, different technologies will have to be explored and developed.     

Water quality management worldwide

This article analyzes water quality on a global scale. An overview of the global water supply and demand situation is presented first, including regional and country information, as well as data on selected water use patterns. The focus then shifts to a discussion of water pollution, its various causes, impact, and remedies, with emphasis on legal and administrative solutions. Water pollution control expenditures and the resultant achievements are dealt with in the final third of the article, with projections to 1995. A wide variety of published sources was dovetailed to obtain a composite picture and most likely scenario; this was supplemented with primary interviews by the author conducted in North America, Western and Eastern Europe, and Oceania at the start of the 1980s.     

Twenty-five years of HAZOPs

The HAZOP or hazard and operability study was developed by ICI over 25 years ago and is in wide use today throughout the world. The technique is intended to review, in a formalized manner, the design of a system such as a chemical process production plant to detect potential problems in the operation of the system. The system has been extended for use on all types of production, storage and distribution units. Experience in the use of hazard studies has lead to the development of a phased approach with three distinct design phases.     

建立我国重大事故预防控制体系之探讨

简述了我国重大工业事故发生的主要原因，提出了建立重大事故预防控制体系的建议，制定《重大事故预防和控制法》，实行重大危险源上报、登记、评价、分级监察管理，建立国家、省、市三级重大事故应急反应系统和重大危险源动态监控网络系统。