INTERNATIONAL MANAGEMENT OF THE RIO GRANDE BASIN THE UNITED STATES AND MEXICO1

ABSTRACT. Despite radical differences in water laws, water management agencies, approaches to water planning, and financial resources, Mexico and the United States forged a common program to manage water and related land on the Rio Grande. Actions of Rio Grande Commissions related to stream gaging, boundary definition, and multiple-purpose construction projects are among the more successful international water-management efforts in the world. Cost-sharing arrangements promoted rapid completing of international works. However, joint action accomplished only part of expectations. International developments were competitive rather than complementary until basin water appropriation was virtually complete. Moreover, Commissions were not empowered to consider long-range competitive water needs, or regional water requirements, throughout the basin. International groundwater use coordination does not exist. International structures produce less than anticipated benefits. Hydroelectric generators are financial liabilities, irrigated acreage exceeds dependable streamflow, and soil salinization is experienced. Unanticipated environmental changes occurred in every major program. The Rio Grande experience points to the need for society to specify goals to which the use of water should contribute and to specify priorities for water use among different sectors of river basins and various segments of society.     

联合国环境规划署（UNEP）的角色演进

环境问题是全球性问题,应对环境问题的需要催生了联合国环境规划署。其是联合国系统内最早成立的专门处理环境问题的机构,且为在全球层面上处理环境问题作出了重要贡献。自1972年成立以来,以里约会议为分界点,联合国环境规划署的发展可分为两个阶段,其在这两个阶段的发展状况有所不同。UNEP成立以来为世界环境保护事业做了很多努力,取得了可喜的成绩,但是世界环境恶化的趋势并没有得到遏制,国际环境管理体制存在着诸多的问题,UNEP面临着巨大的挑战和新的机遇。     

Climate variability,water levels,and fish catch in the Upper East Region of Ghana

The aim of the research was to investigate the effects of climate variability on selected water bodies in the Upper East Region of Ghana using time series decomposition and simple linear regression analyses. Data on temperature and rainfall (1960–2015), annual total fish catch (1996–2016), and the recorded water levels (1987–2015) of a major reservoir, the Tono, were used. Time series decomposition analyses were performed on the rainfall, temperature, and water level data to identify their trends. While temperature was increasing, rainfall was decreasing and resulted in a decrease in the water level in the Tono Reservoir. The decreasing water level in the reservoir made fish catch easier, which led to overfishing. Out of the other 39 dugouts studied, 8 (21%) were silted. Also, rainfall was decreasing at 4.4% per decade and minimum and maximum temperatures were increasing at 2.5% and 0.03% per decade, respectively. The minimum, maximum, and mean water levels of the Tono Reservoir were 3.7, 8.0, and 4.9 meters (m), respectively. The water level of the Tono Reservoir was decreasing by ?0.08 m per year. It is concluded that the water level in the Tono Reservoir was continually decreasing as a result of decreasing rainfall and increasing maximum and minimum temperatures. To maintain a much more stable microclimate and decrease the siltation rate of the reservoirs, farmers are advised to stop farming along the banks of water bodies and avoid clearing vegetation. Fishermen are also encouraged to adopt fish farming in enclosed areas within the reservoir to meet the growing protein demands in the Upper East Region of Ghana.     

导致上西里西亚工业区儿童血铅水平升高环境和社会经济因素研究

本文集中在横向分析近期波兰儿童铅暴露和铅暴露增加背后的社会经济因素。在上西里西亚工业区,铅是分布最广泛的有毒重金属之一。儿童血铅水平升高关系儿童幸福,不断引起严重关切。本研究涉及在1999 - 2013年间,上西里西亚地区3岁到18岁的4 882名儿童。记录了每一个孩子血液中铅的浓度。孩子的父母被要求回答关于儿童接触铅的环境和家庭社会经济条件的问卷调查。铅暴露增加的因素包括：父母受教育程度较低,父母失业、父母的职业铅暴,家庭的贫穷社会经济地位,在家吸烟,生活在建筑物底层,食用本地种植的蔬菜和水果,在污染环境中长期进行户外活动和男性性别。铅的环境暴露仍然是导致上西里西亚地区儿童慢性铅中毒的主要因素。与儿童血铅浓度关系最大的社会经济因素是儿童父母的低教育水平。
精选自Wojciech Pelc, Natalia Pawlas, Micha? Dobrakowski, S?awomir Kasperczyk. Environmental and socioeconomic factors contributing to elevated blood lead levels in children from industrial area of Upper Silesia. Environmental Toxicology and Chemistry: Volume 35, Issue 10, pages 2597–2603, October 2016. DOI: 10.1002/etc.3429
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3429/full
     

Five Hundred Years of Hydrological Drought in the Upper Colorado River Basin1

Abstract: This article evaluates drought scenarios of the Upper Colorado River basin (UCRB) considering multiple drought variables for the past 500 years and positions the current drought in terms of the magnitude and frequency. Drought characteristics were developed considering water‐year data of UCRB’s streamflow, and basin‐wide averages of the Palmer Hydrological Drought Index (PHDI) and the Palmer Z Index. Streamflow and drought indices were reconstructed for the last 500 years using a principal component regression model based on tree‐ring data. The reconstructed streamflow showed higher variability as compared with reconstructed PHDI and reconstructed Palmer Z Index. The magnitude and severity of all droughts were obtained for the last 500 years for historical and reconstructed drought variables and ranked accordingly. The frequency of the current drought was obtained by considering two different drought frequency statistical approaches and three different methods of determining the beginning and end of the drought period (annual, 5‐year moving, and ten year moving average). It was concluded that the current drought is the worst in the observed record period (1923‐2004), but 6th to 14th largest in terms of magnitude and 1st to 12th considering severity in the past 500 years. Similarly, the current drought has a return period ranging from 37 to 103 years based on how the drought period was determined. It was concluded that if the 10‐year moving average is used for defining the drought period, the current drought appears less severe in terms of magnitude and severity in the last 500 years compared with the results using 1‐ and 5‐year averages.     

CLIMATE VARIABILITY AND FLOOD FREQUENCY ESTIMATION FOR THE UPPER MISSISSIPPI AND LOWER MISSOURI RIVERS1

ABSTRACT: This paper considers the distribution of flood flows in the Upper Mississippi, Lower Missouri, and Illinois Rivers and their relationship to climatic indices. Global climate patterns including El Niño/Southern Oscillation, the Pacific Decadal Oscillation, and the North Atlantic Oscillation explained very little of the variations in flow peaks. However, large and statistically significant upward trends were found in many gauge records along the Upper Mississippi and Missouri Rivers: at Hermann on the Missouri River above the confluence with the Mississippi (p = 2 percent), at Hannibal on the Mississippi River (p < 0.1 percent), at Meredosia on the Illinois River (p = 0.7 percent), and at St. Louis on the Mississippi below the confluence of all three rivers (p = 1 percent). This challenges the traditional assumption that flood series are independent and identically distributed random variables and suggests that flood risk changes over time.     

汇流阈值对提取叶尔羌河上游流域面积高程积分的影响

不同地貌单元,其汇流阈值的界定差异较大,而不同的汇流阈值直接影响河流长度、河网密度以及集水区面积的提取结果,因此,汇流阈值的界定是提取流域面积高程积分的关键.以叶尔羌河上游流域为研究对象,基于不同分辨率数字高程模型数据对叶尔羌河上游流域面积高程积分的提取结果,确定适宜分辨率的数字高程模型数据,探讨不同汇流阈值对叶尔羌河...     

Evaluation of the Temporal Transferability of a Model Describing Dissolved Solids in Streams of the Upper Colorado River Basin1

Kenney, Terry A. and Susan G. Buto, 2012. Evaluation of the Temporal Transferability of a Model Describing Dissolved Solids in Streams of the Upper Colorado River Basin. Journal of the American Water Resources Association (JAWRA) 48(5): 1041‐1053. DOI: 10.1111/j.1752‐1688.2012.00667.x Abstract: The application of a nonlinear least‐squares regression model describing the sources and transport of dissolved solids in streams of the Upper Colorado River Basin, and that was calibrated using data from water year 1991, was evaluated for use in predicting annual dissolved‐solids loads for the years 1974 through 1998. Simulations for each water year were run using annual climate data. To evaluate how well the model captures the observed annual variability across the basin, differences in predicted annual dissolved‐solids loads for each simulated year and 1991 were compared with differences in monitored annual loads. The temporal trend of the differences between predicted annual loads for the simulated years and the load for 1991 generally followed the trend of the monitored loads. The model appears to underpredict the largest annual loads and overpredict some of the smaller annual loads. An underprediction bias for wetter years was evident in the residuals as was an overprediction bias, to a lesser degree, for drier years. A regression analysis on the residuals suggests that the underprediction bias is associated with precipitation differences from 1991 and with previously defined downward trends in dissolved‐solids concentrations in the basin. In general, given the representative climatic conditions, the model adequately performs throughout the period examined. However, the model is most transferable to years with climatic conditions similar to 1991.     

安宁河上游冷渍沟泥石流特征及其发展趋势

冷渍沟是安宁河上游左岸的一级支沟,沟内发育了一大型滑坡 碎屑流,为后续泥石流活动提供充足的松散物质来源。为了研究冷渍沟泥石流的危害特征,在野外调查和实地勘测的基础上,分析了泥石流的形成背景条件及其特征,探讨了泥石流的发展趋势,提出了相应的泥石流防治对策。研究表明,冷渍沟泥石流属于过渡性（亚粘性）高频大规模泥石流,泥石流成灾速度快,危害严重;百年一遇的泥石流容重为21 t/m3,五十年一遇的泥石流容重为20 t/m3,二十年一遇害泥石流容重为19 t/m3,相应的峰值流量分别为12768、8171和3818 m3/s。在常态下,冷渍沟泥石流的发生频率和规模会逐渐减小;但如果近期遭遇强震或者暴雨,一旦滑坡失稳堵塞沟道,将会暴发大规模泥石流,很容易堵断安宁河,对上下游造成严重危害。因此,建议在该流域布设必要的泥石流防治工程;同时加强对沟道两岸和滑坡稳定性监测,做好泥石流发生的监测预警工作     

Investigation of the Curve Number Method For Surface Runoff Estimation In Tropical Regions

This study tests the applicability of the curve number (CN) method within the Soil and Water Assessment Tool (SWAT) to estimate surface runoff at the watershed scale in tropical regions. To do this, surface runoff simulated using the CN method was compared with observed runoff in numerous rainfall‐runoff events in three small tropical watersheds located in the Upper Blue Nile basin, Ethiopia. The CN method generally performed well in simulating surface runoff in the studied watersheds (Nash‐Sutcliff efficiency [NSE] > 0.7; percent bias [PBIAS] < 32%). Moreover, there was no difference in the performance of the CN method in simulating surface runoff under low and high antecedent rainfall (PBIAS for both antecedent conditions: ~30%; modified NSE: ~0.4). It was also found that the method accurately estimated surface runoff at high rainfall intensity (e.g., PBIAS < 15%); however, at low rainfall intensity, the CN method repeatedly underestimated surface runoff (e.g., PBIAS > 60%). This was possibly due to low infiltrability and valley bottom saturated areas typical of many tropical soils, indicating that there is scope for further improvements in the parameterization/representation of tropical soils in the CN method for runoff estimation, to capture low rainfall‐intensity events. In this study the retention parameter was linked to the soil moisture content, which seems to be an appropriate approach to account for antecedent wetness conditions in the tropics.