南黄海6.1级地震的中期预报

归纳介绍了１９９５年两篇报告中的中期预报意见及主要依据，并据此讨论了这次中期预报与南黄海６．１级地震的对应关系及今后长南带海域６级以上地震中期预报的思路     

EVALUATION OF THE MAXEY-EAKIN METHOD FOR ESTIMATING RECHARGE TO GROUND-WATER BASINS IN NEVADA1

AESTRACT An evaluation of the Maxey-Eakin method for calculating recharge to ground-water basins in Nevada was performed. The evaluation consisted of comparing Maxey-Eakin estimates with independent estimates of recharge, and analyzing the nature of the differences between the groups of estimates. In the comparison with the Maxey-Eakin estimates, two different groups of independent estimates were used: (1) 40 recharge estimates that were identified from water budgets contained in reports by the Nevada Department of Conservation and Natural Resources and (2) 27 recharge estimates that were identified from previous studies that used models. The results of the comparisons indicate generally good agreement between the Maxey-Eakin estimates and both groups of independent estimates. To quantify this agreement, an analysis was conducted to estimate the uncertainty in the Maxey-Eakin method. The analysis produced an upper bound on the standard deviation of the Maxey-Eakin estimate for a given basin. For the group of 40 water-budget estimates, the upper bound on the standard deviation for an individual basin is 4,800 acre-ft/yr, and the corresponding coefficient of variation of the Maxey-Eakin estimate is no greater than 44 percent. For the group of 27 model estimates, the upper bound on the standard deviation is 4,100 acre-ft/yr, and the corresponding coefficient of variation is no greater than 24 percent.     

海平面上升对海岸带环境的影响与危害及其防治对策

本文阐述了过去近百年来和未来特定年份海平面上升的趋势，分析了海平面上升的原因及其对海岸带环境的影响与危害，最后提出了防治对策与措施。     

山东沿海的9216号台风暴潮灾害

在１９９２年第１６号强热带风暴和天文大潮的作用下，山东沿海发生了特大风暴潮灾害，直接经济损失４３．５亿元，死亡７６人；砂质海岸遭受强烈侵蚀，损失土地约１４５．３ｈａ。     

Identification of critical areas on forest lands for control of nonpoint sources of pollution

Most nonpoint source pollution problems on forest lands can be controlled by careful planning and management of specific critical areas. Critical areas include sites with high mass and surface erosion hazards, overland flow areas, and the riparian zone. Some guides for identifying critical areas are presented along with examples of land-use constraints that might be applied.     

Critique of present wetlands mitigation policies in the united states based on an analysis of past restoration projects in San Francisco Bay

A detailed evaluation of past wetland restoration projects in San Francisco Bay was undertaken to determine their present status and degree of success. Many of the projects never reached the level of success purported and others have been plagued by serious problems. On the basis of these findings, it is debatable whether any sites in San Francisco Bay can be described as completed, active, or successful restoration projects at present. In spite of these limited accomplishments, wetland creation and restoration have been adopted in the coastal permit process as mitigation to offset environmental damage or loss of habitat. However, because the technology is still largely experimental, there is no guarantee that man-made wetlands will persist as permanent substitutes for sacrificed natural habitats. Existing permit policies should be reanalyzed to insure that they actually succeed in safeguarding diminishing wetlands resources rather than bartering them away for questionable habitat substitutes. Coastal managers must be more specific about project requirements and goals before approval is granted. Continued research on a regional basis is needed to advance marsh establishment techniques into a proven technology. In the meantime, policies encouraging or allowing quid pro quo exchanges of natural wetlands with man-made replacements should proceed with caution. The technology and management policies used at present are many steps ahead of the needed supporting documentation.     

THE IMPACTS OF WATERWAY USER FEES ON GRAIN TRANSPORTATION ON THE SNAKE-COLUMBIA RIVER1

ABSTRACT: Grain transportation is a major economic activity on the multiple use Snake-Columbia River System. Congress is currently considering increased transportation user fees aimed at recapturing federal expenditures for waterway operations and maintenance. Three types of fee structure and four levels of cost recovery are evaluated using a network program model. In each case traffic is diverted away from the river to other Puget Sound ports via truck and rail transport modes. Grain shippers in the region will be adversely affected by a higher transport bill. The Lower Columbia River port economic activities will be negatively affected; however, competitive uses of the river, recreation, and hydroelectric generation will likely benefit modestly.     

REGIONAL MANAGEMENT OF DEPLETED AQUIFERS1

ABSTRACT: Aquifers with pressure head seriously reduced by overdrafting are referred to as depleted. In coastal areas they may be invaded by saltwater. An obvious remedy is to reduce the rate of withdrawal to the permanently available dependable yield. This is being done now in two areas for New Jersey, under the authority of the State's Water Supply Management Act; but it has not previously been accomplished on a regional scale. The dependable yield was estimated by means of detailed hydrogeological modeling. “Water Supply Critical Areas” were delimited on the basis of piezometric pressure, drawn down 30 feet below sea level. Within the depleted area, water withdrawals must be reduced by a fixed ratio (35 to 50 percent) below the amount withdrawn during 1983. This reduction is effective as soon as al alternative source of water can be made available, usually from a surface source. Special arrangements are made whereby ground water users unconnected to the alternative source of supply can pay to withdrawn their full needs from the depleted aquifers, the money being used to purchase additional water from the new surface water source, in return for which some other user will reduce his ground water withdrawal below his reduced allocation.     

UPLAND SOIL EROSION SIMULATION FOR AGRICULTURAL WATERSHEDS1

ABSTRACT: A soil erosion simulation model that considered the physical conditions of agricultural watersheds and that interfaced with the modified USDAHL-74 watershed hydrology model was developed. The erosion model simulates the detachment and transport of soil particles caused by raindrop impact and overland flow from rill and interrill areas. The model considers temporal and spatial variation of plant residue, crop canopy cover, snow cover, and the moisture content of surface soil as modifying factors of the erosive forces of raindrop impact and overland flow. The hydrology model simulates overland flow and some of the physical parameters that are used in the erosion model. The simulation is executed in the time interval determined by the rainfall rate or snowmelt rate. The erosion model compares the transport capacity of the overland flow and the sediment loaded in the overland flow to determine the fate account for the free soil particles that have already been detached and are readily available to be transported by the overland flow. The model was tested with data from two small agricultural watersheds in the Palouse region of the Pacific Northwest dryland. The model was calibrated by trial-and-error to determine the coefficients of the model.     

Soil Gas Volatile Organic Compound Concentration Contours for Locating Vadose Zone Nonaqueous Phase Liquid Contamination

Diffusion of VOC from cylindrical vadose zone domains contaminatedwith distributed nonaqueous phase liquid is examined in the steadystate approximation. The effects of first-order biodegradation and ofan extended underlying pool of LNAPL floating on the water table belowthe cylindrical domain are explored by means of an orthogonal functionsapproach. The distribution of VOC in the vadose zone above a floatingcircular LNAPL pool of finite size is explored by a numerical method.The results provide information useful in estimating the spacing anddepth at which soil gas samples should be taken in order to detect thepresence of such source areas. Comparison of model results with soilgas VOC measurements at various depths also provides insight into theextent to which natural biodegradation of the VOCs is taking place.