CHEMISTRY OF COALBED METHANE DISCHARGE WATER INTERACTING WITH SEMI‐ARID EPHEMERAL STREAM CHANNELS1

ABSTRACT: The objective of this study was to examine the chemistry of Coalbed Methane (CBM) discharge water reacting with semi‐arid ephemeral stream channels in the Powder River Basin, Wyoming. The study area consisted of two ephemeral streams: Burger Draw and Sue Draw. These streams are tributaries to the perennial Powder River. Samples were collected bimonthly from three CBM discharge points and seven channel locations in Burger Draw and Sue Draw. Samples were also collected bimonthly from the Powder River above and below the confluence of Burger Draw. Before sample collection, the pH and electrical conductivity (EC) were measured in the field. Samples were transported to the laboratory and analyzed for alkalinity, major cations, and anions. From the measurement of sodium (Na), calcium (Ca), and magnesium (Mg), practical sodium adsorption ratio (SARp) and true sodium adsorption ratio (SARt) were calculated. Results suggest pH and EC of CBM discharge water was 7.1 and 4.3 dS/m, respectively. The CBM discharge water consisted of higher concentrations of sodium and alkalinity compared to other components. The pH of CBM discharge water increased significantly (p = 0.000) in the downstream channel of Burger Draw from 7.1 to 8.84 before it joined with the Powder River. Dissolved calcium concentration of CBM discharge water decreased significantly (p = 0.000) in the downstream channel water. Subsequently, SARp increased approximately from 24 to 29. The SARt also increased significantly (p = 0.001) in the downstream channel water. For instance, SARt of CBM discharge water increased from 32.93 to 45.5 downstream channels after the confluence of Sue Draw with the Burger Draw. The only significant difference in water chemistry above and below the confluence of Burger Draw with the Powder River was pH, which increased from 8.36 to 8.52. The significant increase in SAR values of CBM discharge water in Burger Draw and Sue Draw tributaries suggest a careful monitoring of salinity and sodicity is needed if CBM discharge water is used for irrigation in semi‐arid environments. Results discussed in this study will be useful to downstream water users who depend on water for irrigation.     

Water Management Decision Making in the Face of Multiple Forms of Uncertainty and Risk

In the Wasatch Range Metropolitan Area of Northern Utah, water management decision makers confront multiple forms of uncertainty and risk. Adapting to these uncertainties and risks is critical for maintaining the long‐term sustainability of the region's water supply. This study draws on interview data to assess the major challenges climatic and social changes pose to Utah's water future, as well as potential solutions. The study identifies the water management adaptation decision‐making space shaped by the interacting institutional, social, economic, political, and biophysical processes that enable and constrain sustainable water management. The study finds water managers and other water actors see challenges related to reallocating water, including equitable water transfers and stakeholder cooperation, addressing population growth, and locating additional water supplies, as more problematic than the challenges posed by climate change. Furthermore, there is significant disagreement between water actors over how to best adapt to both climatic and social changes. This study concludes with a discussion of the path dependencies that present challenges to adaptive water management decision making, as well as opportunities for the pursuit of a new water management paradigm based on soft‐path solutions. Such knowledge is useful for understanding the institutional and social adaptations needed for water management to successfully address future uncertainties and risks.     

Influence of Riparian Seepage Zones on Nitrate Variability in Two Agricultural Headwater Streams

Riparian seeps have been recognized for their contributions to stream flow in headwater catchments, but there is limited data on how seeps affect stream water quality. The objective of this study was to examine the effect of seeps on the variability of stream NO₃‐N concentrations in FD36 and RS, two agricultural catchments in Pennsylvania. Stream samples were collected at 10‐m intervals over reaches of 550 (FD36) and 490 m (RS) on 21 occasions between April 2009 and January 2012. Semi‐variogram analysis was used to quantify longitudinal patterns in stream NO₃‐N concentration. Seep water was collected at 14 sites in FD36 and 7 in RS, but the number of flowing seeps depended on antecedent conditions. Seep NO₃‐N concentrations were variable (0.1‐29.5 mg/l) and were often greater downslope of cropped fields compared to other land uses. During base flow, longitudinal variability in stream NO₃‐N concentrations increased as the number of flowing seeps increased. The influence of seeps on the variability of stream NO₃‐N concentrations was less during storm flow compared to the variability of base flow NO₃‐N concentrations. However, 24 h after a storm in FD36, an increase in the number of flowing seeps and decreasing streamflow resulted in the greatest longitudinal variability in stream NO₃‐N concentrations recorded. Results indicate seeps are important areas of NO₃‐N delivery to streams where targeted adoption of mitigation measures may substantially improve stream water quality.     

液化和压缩气体半球形扩散模型集的构建和应用

国内外液化和压缩气体的泄漏爆炸事故屡见不鲜,针对其性质和短时间近地面扩散的特点,总结、修正和扩展了瞬时泄漏下的平均半球形扩散模型。对于连续泄漏,利用数学积分理论建立了静风下的半球形扩散模型。接着对有风时的情况进行建模推导,将风速和气体自身扩散速度进行矢量合成,得到了半椭球形扩散和半椭圆锥与1/4椭球体组合扩散下气体的质量浓度和质量浓度变化趋势。最后用实例验证了该模型的先进性。该模型集能较好地反映液化和压缩气体泄漏后不同泄漏情况、时间、近地面区域和风速下的扩散浓度空间分布及其动态变化过程,为事故后果预估和应急救援决策提供参考。     

循环流化床干法脱硫除尘一体化工艺去除汞探讨研究

目前,由于人类污染源每年向大气排汞量日益增长,使国际上对汞排放的控制研究成为热点,本文通过理论计算及工程实例说明了循环流化床干法烟气脱硫除尘一体化工艺系统可以有效地控制燃煤电厂汞的排放。     

化学需氧量半微量烘箱测定方法的研究

介绍了污水和工业废水中化学需氧量(COD)的半微量烘箱测定方法。该法与经典回流法比较,具有节省水电、省时、省药品等特点。用Ag2SO4-MnSO4作催化剂,HgSO4用量少,减少了汞盐的二次污染。具有较好的精密度和准确度,适用于大批量的水样的测定,有良好的推广价值。     

Competition of the active roots of Cassia siamea Lam. and Zea mays L.(cv.Katumani Composite B) in an alley cropping trial in semi arid Kenya

ＩｎｔｒｏｄｕｃｔｉｏｎＯｎｅｏｆｔｈｅｍａｊｏｒｄｒａｗｂａｃｋｓｏｆａｌｌｅｙｃｒｏｐｐｉｎｇｓｙｓｔｅｍｓｉｎｓｅｍｉａｒｉｄｌｏｗｆｅｒｔｉｌｉｔｙｃｏｎｄｉｔｉｏｎｓｉｓｃｏｍｐｅｔｉｔｉｏｎｆｏｒａｖａｉｌａｂｌｅｗａｔｅｒａｎｄｎｕｔｒｉｅｎｔｓ．Ｃｏｍｐｅｔｉｔｉｏｎｉｓｔｏｂｅｅｘｐｅｃｔｅｄｉｆｔｈｅｔｒｅｅａｎｄｔｈｅｃｒｏｐｈａｖｅｏｖｅｒｌａｐｐｉｎｇａｃｔｉｖｅｒｏｏｔｓｙｓｔｅｍｓｉｎｓｐａｃｅａｎｄｔｉｍｅ．Ａｋｎｏｗｌｅｄｇｅｏｆｔｈｅｓｐａｔｉａｌｄｉｓｔｒ…     

半干半湿法烟气脱硫装置中喷雾增湿技术的研究

脱硫塔内喷雾增湿技术是影响燃煤锅炉半干半湿法烟气脱硫效果的一个重要环节。分析了供水量和压力的变化关系 ,通过对脱硫装置喷雾增湿技术的优化 ,实现对增湿系统高压水的压强的精确调节 ,控制脱硫塔内雾滴的颗粒直径在 80 μm左右 ,从而达到理想的增湿效果     

Understanding yields in alley cropping maize (Zea mays L.) and Cassia siamea Lam. under semi-arid conditions in Machakos, eastern Kenya

ＩｎｔｒｏｄｕｃｔｉｏｎＯｎｌｙａｂｏｕｔ 2 0 %ｏｆＫｅｎｙａ’ｓｔｏｔａｌｌａｎｄａｒｅａｈａｓｈｉｇｈｐｏｔｅｎｔｉａｌｆｏｒａｇｒｉｃｕｌｔｕｒａｌｐｒｏｄｕｃｔｉｏｎ ,ｔｈｅｒｅｓｔｂｅｉｎｇａｒｉｄｏｒｓｅｍｉ ａｒｉｄ .ＴｈｅａｎｎｕａｌｐｏｐｕｌａｔｉｏｎｇｒｏｗｔｈｒａｔｅｉｎＫｅｎｙａｏｆｃｌｏｓｅｔｏ 4 %ｉｓｏｎｅｏｆｔｈｅｈｉｇｈｅｓｔｉｎｔｈｅｗｏｒｌｄ (ｅ .ｇ .ＵｎｉｔｅｄＮａｔｉｏｎｓＤｅｖｅｌｏｐｍｅｎｔＰｒｏｇｒａｍｍｅ ,1990 ) .Ｔｈｉｓｓｉｔｕａｔｉｏｎｈａｓｌ…     

Response of photosynthesis,morphology and growth of Hedysarum mongolicum seedlings to simulated precipitation change in Maowusu sandland

ＩｎｔｒｏｄｕｃｔｉｏｎＭａｏｗｕｓｕｓａｎｄｌａｎｄ ,ａｓｅｍｉ ａｒｉｄａｒｅａｏｆＣｈｉｎａ,ｌｉｅｓｏｎｍｉｄｄｌｅｐａｒｔｏｆＣｈｉｎｅｓｅｎｏｒｔｈｄｅｓｅｒｔ (Ｙａｏ ,1 992 ) .Ａｔｐｒｅｓｅｎｔ,ｄｅｓｅｒｔｉｆｉｃａｔｉｏｎｉｓｂｅｃｏｍｉｎｇｍｏｒｅｓｅｒｉｏｕｓａｎｄｔｈｅｌａｎｄｓｃａｐｅｃｏｍｐｒｉｓｅｓｌａｒｇｅａｒｅａｓｏｆｓａｎｄ ｃｏｖｅｒｅｄｌａｎｄｔｈｅｒｅ(Ｚｈａｎ ,1 994;Ｃｈｉ,1 994) .Ｔｈｅｅｎｖｉｒｏｎｍｅｎｔｉｓｃｈａｒａｃｔｅｒｉｚｅｄｂｙｗａｔｅｒｓ…