GROUND-WATER RECHARGE THROUGH ACTWE SAND DUNES IN NORTHWESTERN NEVADA1

ABSTRACT: Most water-resouree investigations in semiarid basins of the Great Basin in western North America conclude that ground-water recharge from direct precipitation on the valley floor is negligible. However, many of these basins contain large areas covered by unvegetated, active sand dunes that may act as conduits for ground-water recharge. The potential for this previously undocumented recharge was investigated in an area covered by sand dunes in Desert Valley, northwestern Nevada, using a deep percolation model. The model uses daily measurements of precipitation and temperature th determine energy and moisture balances, from which estimates of long-term mean annual recharge are made. For the study area, the model calculated a mean annual recharge rate of as much as 1.3 inches per year, or 17 percent of the long-term mean precipitation. Model simulations also indicate that recharge would be virtually zero if the study area were covered by vegetation rather than dunes.     

STREAM TEMPERATURE ESTIMATION FROM AIR TEMPERATURE1

ABSTRACT: Air temperatures are sometimes used as substitutes for stream temperatures. To examine the errors associated with this procedure, linear relationships between stream temperatures, T, and air temperatures, T_a, recorded for 11 streams in the central U.S. (Mississippi River basin) were analyzed. Weather stations were an average 42 miles (range 0 to 144 miles) from the rivers. The general equations, T_w= 5.0 + 0.75 T_a and T_w= 2.9 + 0.86 T_a with temperatures in °C, were derived for daily and weekly water temperatures, respectively, for the 11 streams studied. The simulations had a standard deviation between measurements and predictions of 2.7°C (daily) and 2.1°C (weekly). Equations derived for each specific stream individually gave lower standard deviations, i.e., 2.1°C and 1.4°C, respectively. Small, shallow streams had smaller deviations than large, deep rivers. The measured water temperatures follow the air temperatures closely with some time lag. time lags ranged from hours to days, increasing with stream depth. Taking into account these time lags improved the daily temperature predictions slightly. Periods of ice cover were excluded from the analysis.     

山东省水环境自动监测监控系统数据的应用设计和使用方法

山东省水环境自动监测监控子系统的主要功能是将全省水质自动站数据利用计算机网络、数据仓库等技术导入到环境监测数据仓库中，实现全省水环境自动监测的统一监控和监测信息的自动管理和发布。本文简单介绍了系统担制中心端监测数据统计应用部分的功能设计和实现方法。     

山东省城市空气自动监测监控系统数据的应用设计和使用方法

山东省城市空气自动监测监控系统的主要功能是将全省城市自动监测站数据利用计算机网络、数据仓库等技术导入到环境监测数据仓库中，实现全省城市空气质量自动监测的统一监控和监测信息的自动管理和发布。本文简单介绍了系统控制中心端监测数据统计应用部分的功能设计和实现方法。     

Water Use by Thermoelectric Power Plants in the United States1

Abstract: Thermoelectric power generation is responsible for the largest annual volume of water withdrawals in the United States although it is only a distant third after irrigation and industrial sectors in consumptive use. The substantial water withdrawals by thermoelectric power plants can have significant impacts on local surface and ground water sources, especially in arid regions. However, there are few studies of the determinants of water use in thermoelectric generation. Analysis of thermoelectric water use data in existing steam thermoelectric power plants shows that there is wide variability in unitary thermoelectric water use (in cubic decimeters per 1 kWh) within and among different types of cooling systems. Multiple‐regression models of unit thermoelectric water use were developed to identify significant determinants of unit thermoelectric water use. The high variability of unit usage rates indicates that there is a significant potential for water conservation in existing thermoelectric power plants.     

Demonstrating Floodplain Uncertainty Using Flood Probability Maps1

Abstract: The U.S. Federal Emergency Management Agency (FEMA) flood maps depict the 100‐year recurrence interval floodplain boundary as a single line. However, because of natural variability and model uncertainty, no floodplain extents can be accurately defined by a single line. This article presents a new approach to floodplain mapping that takes advantage of accepted methodologies in hydrologic and hydraulic analysis while including the effects of uncertainty. In this approach, the extents of computed floodplain boundaries are defined as a continuous map of flood probabilities, rather than as a single line. Engineers and planners can use these flood probability maps for viewing the uncertainty of a floodplain boundary at any recurrence interval. Such a flood probability map is a useful tool for visualizing the uncertainty of a floodplain boundary and represents greater honesty in engineering technologies that are used for flood mapping. While institutional barriers may prevent adoption of such definitions for use in graduated flood insurance rates (as most other insurance industries use to account for relative risks), the methods open the door technically to such a reality.     

Normality of Hydrological Data1

ABSTRACT: Assessment of normality of hydrological data has been based upon subjective judgments. This paper aims to provide an objective method for such an assessment by introducing three computationally simple statistical tests. Application to some stream flow data indicates that (1) for annual values, at least one of the three sequences- original, square root, and logarithmic - can be considered to be normally distributed; and (2) most monthly stream flows are skew and neither the square root nor the logarithmic transformation is able to render their sequences in all the 12 months normal.     

NUMERICAL MODEL OF A TRACER TEST ON THE SANTA CLARA RWER,VENTURA COUNTY,CALIFORNIA1

ABSTRACT: To better understand the flow processes, solute-trans. port processes, and ground-water/surface-water interactions on the Santa Clara River in Ventura County, California, a 24-hour fluorescent-dye tracer study was performed under steady-state flow conditions on a 45-km reach of the river. The study reach includes perennial (uppermost and lowermost) subreaches and ephemeral subreaches of the lower Piru Creek and the middle Santa Clara River. The tracer-test data were used to calibrate a one-dimensional flow model (DAFLOW) and a solute-transport model (BLTM). The dye-arrival times at each sample location were simulated by calibrating the velocity parameters in DAFLOW. The simulations of dye transport indicated that (1) ground-water recharge explains the loss of mass in the ephemeral middle subreaches, and (2) ground-water recharge does not explain the loss of mass in the perennial uppermost and lowermost subreaches. The observed tracer curves in the perennial subreaches were indicative of sorptive dye losses, transient storage, and (or) photodecay - these phenomena were simulated using a linear decay term. However, analysis of the linear decay terms indicated that photodecay was not a dominant source of dye loss.     

空间视角下湖北省环境绩效评估及影响因素分析

以湖北省为例，基于压力-状态-响应（PSR）模型构建环境绩效评估指标体系，运用空间自相关和标准差椭圆对湖北省各地区绩效指数空间特征及影响因素进行探讨，结果显示：湖北省各地区环境绩效指数（EPI）均高于60，但普遍处于中等水平，良好及优秀所占比例低.EPI较高的地区主要位于湖北省西部和中部，压力和状态指数从西至东递减，响应指数则呈现东部高于西部高于中部的态势.状态指标绩效指数在空间上显著正相关，即环境质量状况较好（或较差）的地区在空间上集聚.EPI及二级指标绩效指数均以西北-东南为布局方向，且EPI椭圆重心较于基准重心偏向于西南方向.各地区环境指数除受到资源禀赋的影响外，还与城镇化率和人口密度显著相关.