STATIC WATER LEVEL MAPPING IN EAST CENTRAL MICHIGAN1

ABSTRACT: This paper presents a methodology for preparing a static water level map using a sample of water level measurements obtained from the well log records of private wells that are finished in glacial drift. The test was conducted in Tyrone Township, located in east central Michigan. A variety of selection criteria were examined and the resulting maps were compared with a ground truth map that was prepared from water level measurements obtained in the field. The map prepared from a random sample of wells at a density of two points per section best approximates the ground truth map. Using a sample of records from the Michigan Statewide Groundwater Database to create static water levels that are used in community ground water vulnerability analyses will provide a more accurate map than using the complete dataset or other selection criteria based on temporal groupings or seasonality.     

污泥处置与资源化新技术探讨

文章系统地综述了国内外城市污泥处置与利用的现状，讨论了近年来污泥处置以及资源化新技术的研究进展。指出污泥的减量化、资源化和无害化是符合我国的实际情况的污泥处置方法。     

OXYGEN DEMAND IN ICE COVERED LAKES AS IT PERTAINS TO WINTER AERATION1

ABSTRACT: Winterkill, the death of fish under ice due to oxygen deficiency, threatens hundreds of shallow lakes in the upper Midwest of the United States every winter. For decades, attempts have been made to prevent winterkill, usually through aeration, with mixed results. In large part, the failure of strategies to prevent winterkill can be linked to a lack of understanding of winter limnology and in particular, of oxygen dynamics under ice. Most winterkill lakes behave as closed systems with regard to oxygen. Consequently, the oxygen content of an ice and snow covered lake is essentially a function of the amount of initial storage and the rate of depletion. Should the stored oxygen be insufficient to prevent near anoxia before melting of the ice cover occurs, winterkill will result. Most oxygen consumption in ice covered lakes is due to bacterial respiration and chemical oxidation at the sediment/water interface, the remainder occurring in the water column. Oxygen consumption (and thus depletion) is a function of the velocity and oxygen concentration of the near sediment water. This is due to the fact that oxygen transport to the sediment is mediated by a diffusive boundary layer adjacent to the sediment surface. Winter oxygen depletion rates decrease when the oxygen concentration of the overlying water falls below about 3 mg/l. Aeration techniques which increase the oxygen concentration and velocity of the near-sediment water also increase the oxygen consumption (depletion) rate.     

A STAGE DISTRIBUTION APPROACH TO ESTIMATING ICE RELATED FLOODING PROBABILITIES1

ABSTRACT: A procedure is presented for estimating flooding probabilities resulting from either open water or ice condition events. The methodology involves individually fitting a distribution function to water stages from open water and ice events and determining the composite probability of exceedence of any stage value. The parameters of the two distribution functions are estimated using censored maximum likelihood. The approach is evaluated with a Monte Carlo sampling program and is applied to estimate flooding probabilities on the Yukon River.     

Pesticide and Transformation Product Detections and Age‐Dating Relations from Till and Sand Deposits1

Abstract:  Pesticide and transformation product concentrations and frequencies in ground water from areas of similar crop and pesticide applications may vary substantially with differing lithologies. Pesticide analysis data for atrazine, metolachlor, alachlor, acetochlor, and cyanazine and their pesticide transformation products were collected at 69 monitoring wells in Illinois and northern Indiana to document occurrence of pesticides and their transformation products in two agricultural areas of differing lithologies, till, and sand. The till is primarily tile drained and has preferential fractured flow, whereas the sand primarily has surface water drainage and primary porosity flow. Transformation products represent most of the agricultural pesticides in ground water regardless of aquifer material – till or sand. Transformation products were detected more frequently than parent pesticides in both the till and sand, with metolachlor ethane sulfonic acid being most frequently detected. Estimated ground‐water recharge dates for the sand were based on chlorofluorocarbon analyses. These age‐dating data indicate that ground water recharged prior to 1990 is more likely to have a detection of a pesticide or pesticide transformation product. Detections were twice as frequent in ground water recharged prior to 1990 (82%) than in ground water recharged on or after 1990 (33%). The highest concentrations of atrazine, alachlor, metolachlor, and their transformation products, also were detected in samples from ground water recharged prior to 1990. These age/pesticide detection relations are opposite of what would normally be expected, and may be the result of preferential flow and/or ground‐water mixing between aquifers and aquitards as evident by the detection of acetochlor transformation products in samples with estimated ground‐water ages predating initial pesticide application.     

火灾下大空间结构温度场的数值模拟分析

大空间结构近年来在我国得到了迅速的发展,然而,我国原有防火规范常常无法满足该类结构防火设计的需要。目前性能化设计方法是防火研究领域的发展趋势,而结构内部温度场的准确计算与否是其中非常关键的重要环节。笔者利用流体动力学计算软件FLUENT对不同火灾曲线和火源功率下,典型尺寸模型的温度场随时间与空间的分布情况进行了计算模拟,并与我国《钢结构防火技术规程》(征求意见稿)中近似公式计算结果相对比,同时对规范中未规定的火源功率可否使用已知值采用线性插值方法求解进行了讨论,并深入分析了此简化计算公式存在的局限性。     

Water input requirements of the rapidly shrinking Dead Sea

The deepest point on Earth, the Dead Sea level, has been dropping alarmingly since 1978 by 0.7 m/a on average due to the accelerating water consumption in the Jordan catchment and stood in 2008 at 420 m below sea level. In this study, a terrain model of the surface area and water volume of the Dead Sea was developed from the Shuttle Radar Topography Mission data using ArcGIS. The model shows that the lake shrinks on average by 4 km²/a in area and by 0.47 km³/a in volume, amounting to a cumulative loss of 14 km³ in the last 30 years. The receding level leaves almost annually erosional terraces, recorded here for the first time by Differential Global Positioning System field surveys. The terrace altitudes were correlated among the different profiles and dated to specific years of the lake level regression, illustrating the tight correlation between the morphology of the terrace sequence and the receding lake level. Our volume-level model described here and previous work on groundwater inflow suggest that the projected Dead Sea–Red Sea channel or the Mediterranean–Dead Sea channel must have a carrying capacity of >0.9 km³/a in order to slowly re-fill the lake to its former level and to create a sustainable system of electricity generation and freshwater production by desalinization. Moreover, such a channel will maintain tourism and potash industry on both sides of the Dead Sea and reduce the natural hazard caused by the recession.     

H2O2存在条件下冰相中苯酚的光化学转化

研究了在125W高压汞灯照射下,低温(-14～-12℃)反应装置中H2O2存在条件下冰相中苯酚的光转化反应,考察r冰相中苯酚光转化的影响因素以及光转化动力学过程.结果表明,冰相中苯酚光转化速率随着光强和H2O2初始浓度的增加而加快,随着苯酚初始浓度的增加而减慢;强酸条件促进了苯酚的光转化;苯酚的光解速率符合一级动力学模式.苯酚光解产物的GC-MS和LC-MS分析表明,苯酚在光解过程巾主要发乍了羟基化反应和偶联反应.     

含油污泥减量化及影响因素研究

对某炼油厂含油污泥进行了减量化处理,并研究了影响污泥减量化的影响因素。研究表明,以三氯化铁、阳离子型聚丙烯酰胺(CPAM)和生石灰复合调质处理含油污泥后,经过55 kPa(绝)抽滤,可使含水率由98.6%下降到70.3%,体积减少为原来污泥脱水后体积的71.43%,大大降低了含油污泥的体积,实现了含油污泥的减量化。以PR-A复合药剂为调质剂,在温度为70℃～80℃,pH值为4.0～5.0,搅拌时间为30 min条件下,经55 kPa(绝压)抽滤后,含油污泥的处理效果最好,滤饼含水率可达到70.3%,进一步方便含油污泥的后续处理,有利于污泥的资源化利用和无害化处理。     

非饱和马兰黄土土-水特征曲线研究

本文通过对西气东输管线子长县—永平镇段原状马兰黄土的基本物理力学性质进行试验,分析了非饱和马兰黄土土样的基本性质,并利用2Bar体积压力板仪对该土样的基质吸力和体积含水量进行了研究,得出其土-水特征曲线,同时分别采用Gardner、Fredlund和Xing以及Van Genuchten土-水特征曲线方程对试验数据进行...