岷江大桥控制单元水体氨氮和总磷源解析

采用单因素法对岷江流域国控断面的岷江大桥水体进行评价,从污染源分担率、污染物时空变化等方面解析污染物的主要来源与变化。结果表明,水体不达标的主要因子为氨氮和总磷;污染物的主要来自城镇生活污水和规模化畜禽养殖废水的不达标排放,按各个污染源占比统计,2个主要污染源对于氨氮和总磷的污染分担率分别是42.54%、35.31%;受上游来水、其他补给水源的影响,氨氮浓度集中在1~5月超标严重,在2013年4月份出现峰值,总磷在2011~2014年普遍超标严重,在2014年5月出现峰值,由于"十二五"期间治污力度的加强,2015年氨氮污染趋势得到控制,总磷浓度明显有所降低,MIKE 21二维水动力水质模型模拟显示只要汇入支流断面均达到要求、污染负荷得到有效控制,控制单元能满足达标要求;最后从源头减排、区域综合整治、全程监管3个方面构建了使控制单元水体达标的策略。     

Anthropometric evaluation of cockpit designs

The objective of this research is to evaluate all the critical reaches in a cockpit and determine the visual sufficiency of a cockpit to accommodate 90% of potential pilots. While mismatches of measurements with cockpit dimensions are revealed, proposals are made to improve cockpit ergonomics. Regression models were generated to predict and assure adequate exterior vision. Mean, lower and upper control limits of all measurements were found acceptable except eye level. There are very strong positive relationships between stature and eye level (R²?=?0.972, p?R²?=?0.994, p?SD smaller than the eye level mean or seating adjustment limits in height may be changed. In general, cockpit design is acceptable in terms of fit/reach accommodation for pilots, except eye level and visual variables that could be solved by better seat adjustments.     

FLUVIAL GEOMORPHOLOGICAL METHODOLOGY FOR NATURAL STABLE CHANNEL DESIGN1

A fluvial geomorphological methodology for designing natural stable channels is being widely applied for river restoration. It is an analogue procedure, as the W/d ratio and sinuosity from a reference reach are scaled to determine the restoration design. The choice of reference reach is crucial and published criteria specify that it should be stable, correspond to the stream type at the restoration site, have the same valley type, and be from the same hydrophysiographic region. For stable, meandering gravel cobble bed rivers flowing through alluvial flood plains (C3 and C4 stream types), UK regime equations are used to evaluate the procedure. Successful design requires particular combinations of the ratios of bankfull discharge, bed material size and load, valley slope, and bank vegetation category between the reference and restoration sites. These critical ratios, which are confirmed by U.S. field data, provide guidelines for selecting a suitable reference reach for C3‐C4 stream types. They also indicate that the reference reach can be in any valley type or hydrophysiographic region. The geomorphological procedure will apply to all stable stream types, provided the reference reach is correctly identified. Specific guidelines for each stream type await the development of additional regime equations.     

A STATISTICAL METHODOLOGY FOR PREDICTING THE POLLUTANTS IN A RIVER1

Urban and industrial areas continue to expand and consequently, to create serious water pollution problems to natural streams. The need for the development of accurate, reliable, and sensitive water quality prediction models is most desirable. The first objective of this research is to set guidelines for dividing a natural stream into more or less independent reaches based on some criteria. The second objective is to obtain the predicting equations of the water pollutants in a selected stream. The preliminary phase of this research evaluated water quality data sampled from the Pearl River which flows southwest and then turns south through the states of Mississippi and Louisiana. This evaluation served as guidelines to divide the total river basin into reaches (subsystems) appropriate to the objective of this research. Subsequent to this subsystem assignment, a stepwise multiple regression FORTRAN program was used to regress the pollutants (dependent variables) for both time and space on their water characteristics (independent variables). Based on the results obtained, the proposed statistical approach provides a practical tool for developing regression equations for the purpose of water pollutants' prediction.     

三峡入库河流澎溪河回水区消落带与岸边土壤磷形态及其分布特征研究

应用沉积物中磷形态的分级提取法对三峡入库河流澎溪河回水区消落带和岸边土壤不同形态P进行分级测定,分析了各形态磷之间以及各形态磷与样品理化性质.结果表明,消落带土壤总磷含量在283.3～3281.6mg.kg-1之间,平均为780.6mg.kg-1,岸边土壤中总磷含量在395.0～1751.5mg.kg-1之间,平均含量...     

闽江下游北港河段污染物运动特性模拟与分析

建立了闽江下游北港河段二维水动力、水质耦合模型,对不同排污口污染带特征进行了分析比较,结果表明：排污口的布置对北港水质有很大影响,在排放相同浓度相同流量的污染物时,各排污口污染带长度和宽度完全不同。各排污口污染带长度明显大于宽度,彬德闸、江泗闸产生的污染带比较短,五孔闸、九孔闸污染带很长,在排放流量为40m^3／s,排放浓度为15mg/L时,在彬德闸或江泗闸排放对东南水厂水质影响较小,在五孔闸或九孔闸排放对东南水厂造成很大的影响。     

通吕运河控制断面水质达标分析

文章通过通吕运河规划区域内南通主城区、通州区、海门市、启东市污染物现状入河量和预测量的计算,将通吕运河全线划分为四个水质控制断面,并采用河流一维稳态水质模型对通吕运河沿程水质变化情况进行数值模拟,进行通吕运河四个控制断面水质达标分析,得出选定的四个控制断面水质在不同的污染物入河量时达到地表水环境功能区水质目标需要削减的化学需氧量、氨氮、总磷的排放量,为通吕运河的水环境综合整治提供技术支撑。     

珠江广州河段上覆水和间隙水中磷特性研究

通过研究污染比较严重的珠江广州河段(雅岗至琶洲大桥)的六个断面,共10个采样点的上覆水和间隙水的磷形态分布特征,得上覆水总磷(TP)值为0.705～3.893mg/L,均为劣V类水质。总溶解性磷(TDP)与磷酸盐磷(PO43-)在各采样点的含量分布不均匀,由PO43-含量显示,各采样点已经有明显的富营养化趋势。通过分析各采样点间隙水磷含量和引起其上下层含量差异的环境因素知间隙水TP与TDP有一定相关性。间隙水上下层TP,TDP,PO43-含量差异可能与沉积物有机质和氧化还原环境有一定相关性,总体上认为厌氧环境有利于促进沉积物的磷释放到间隙水。     

基于遗传算法的次级河流回水段水质模型多参数识别

根据长江次级河流临江河回水段的实际情况,建立一维水质模型,模型中的各变化项采用有限差分法(FDM)进行离散,以回水段水体中COD和NH3-N的实测资料为基础,利用自适应遗传算法(AGA)对2种污染物的纵向离散系数及一级降解系数进行反演计算,得出回水段COD和NH3-N的纵向离散系数分别为0.5227,0.5196km2/h,一级降解系数分别为0.0342,0.0367h-1;计算值与实测值吻合较好,表明FDM-AGA方法能较好地运用于次级河流回水段水质模型的多参数识别.     

农业气候资源变化对双季稻生产的可能影响分析

基于长江中游地区50 个气象台站自1960 年以来的历年地面气象观测资料,分1960-2009 及1960-1984、1985-2009 年3 个不同时间段,分温度生长期、早稻生长期、晚稻生长期分别分析了热量、光照、降水等农业的变化特征,并讨论对双季稻生产的可能影响。1960-2009年,该地区温度生长期平均气温、平均日最低气温、平均日最高气温的平均增速分别为0.08 ℃/10 a、0.09 ℃/10 a、0.07 ℃/10 a,≥10 ℃活动积温的平均增速为66.3 ℃/10 a,日照时数的平均减速为31.7 h/10 a,降水量的平均增速为3.7 mm/10 a。表现为温度上升、积温增加、温度生长期延长、日照时数减少、降水量微弱增加的变化特征。温度升高、积温增加可能导致发育速度加快、生育期缩短、病虫害加重,日照时数减少可能影响叶片光合及产量。早稻生长期的平均气温、≥10 ℃活动积温的增速分别为0.20 ℃/10 a、48.9 ℃/10 a,晚稻生长期分别为0.09 ℃/10 a、14.6 ℃/10 a,早稻和晚稻生长期间日照时数的下降速率分别为18.6 h/10 a、42.7 h/10 a,降水量的增加速率分别为1.9 mm/10 a、8.7 mm/10 a,表现为升温速率早稻大于晚稻,日照时数下降速率晚稻大于早稻,降水量增加速率晚稻大于早稻。早稻期间升温和积温增加明显可能有利于早稻提前播种、选用生育期稍长的品种、提高产量潜力和产量,晚稻期间升温不明显且日照时数下降则可能不利于群体光合和产量形成,影响其产量潜力和产量。区域中的江汉平原、洞庭湖平原等基础条件好的地区,其热量、日照、降水同步增加,其他地区则表现为热量、降水增加,但日照时数下降,要充分发挥其基础条件好与气候资源丰富且同步增加等优势,发展高效规模化生产,增强稻谷生产能力。