Is sluice gate management beneficial for spawning migrations? The case of the shark catfish (Helicophagus waandersii) in the Mun River below the Pak Mun Dam,Thailand

The reproductive ecology of shark catfish Helicophagus waandersii in the Mun River, the largest Mekong tributary in Thailand, was studied from July 2003 to December 2004. The aim of the study was to determine whether shark catfish, which contribute greatly to fish catches, benefits in terms of spawning, from the management regime of the Pak Mun Dam to open all sluice gates annually for 4 months during the rainy season. In total, 228 females were studied. The highest average gonadosomatic index (4.42% ± 1.90%) was observed in the rainy season in June 2004. Fecundity ranged from 21 550 to 191 540 eggs. Three hormonal profiles viz. testosterone (T), 17 β‐estradiol (E₂), and 17, 20 β‐dihydroxy‐4‐pregnen‐3‐one (17, 20 βP) were determined by radioimmunoassay. The highest levels of T (0.96 ng ml⁻¹), E₂ (14.37 pg ml⁻¹), and 17, 20 βP (0.81 ng ml⁻¹) were respectively measured in April to May, July, and May. Changes in the maturity stage and the annual sex hormonal profiles revealed that the spawning period of H. waandersii is from May to June. There was no spatial statistical difference (p > 0.05) for each sex steroid profiles. The results indicated that H. waandersii spawn during the rainy season in the rapid areas, both downstream and upstream, and the sluice gates opening management regime for 4 months in the rainy season is of advantage for H. waandersii in terms of feeding and nursery grounds in the upstream area. Copyright © 2006 John Wiley & Sons, Ltd.     

三峡水库建成后对长江中下游江湖水沙关系变化趋势初探Ⅰ:大型河网水沙数模的建立与验证

对于天然河道的数学模拟计算中,特别是长江中下游的干支流、洞庭湖区等,会出现较多分流、汇流、分流比未知的分汉河段,形成水流顺逆不定、复杂多变的河网,为此,本文在用四点带权隐式差分求解非恒定流的基础上,通过消元、转换,建立了河网水沙数学模型.该模型既可解决复杂的河网水流计算问题,亦适用于长河段、长时段的较复杂的天然河道水流计算问题.通过对长江中下游千支流洪水过程的模拟,水位、流量、输沙量及洪水过程与实测值相比均在误差范围内,说明该数学模型合理可行,可扩展应用.计算迅捷简便,应用性强.     

河湖普查若干问题的讨论

编制河流名录和水系编码,是河湖普查工作的重要内容之一.提出了甄别和统计河流干支流的原则:①以河流最长的一条为干流,或者以集水面积最大的一条为干流;②各支流的长度、面积接近时,则以水量明显很大的一条为干流;③各支流的长度、面积、水量均接近时,取河道宽广、河谷平缓顺直、上下段自然延伸的一条为干流;④要充分尊重历史上合理的传统称谓.确定河流源头的方法主要有3种:①河流向上溯源交于分水岭,其交点就是河流的源头;②在数字综合水系图上搜索河槽线上端最末端处,其最小集水面积定义为0.2 km2;③河流上源开始有水的地方,"水"包括泉水、小溪、沼泽、湖泊、冰川融水等,但有水即源的方法存在一些缺点.     

三峡库区典型支流氢氧同位素时空分布特征研究

定量分析三峡水库支流库湾中水体组成,研究支流库湾水循环过程,有助于分析支流库湾的环境问题。对三峡水库内的草堂河及其毗邻干流进行了连续1 a的观测,分析了水体中氢氧同位素特征,阐述了在干支流相互作用下,三峡水库支流库湾的水团来源及其组成,探讨了三峡水库蓄水后支流库湾水循环的变化。研究表明:长江干流和支流库湾中δD/δ~(18)O与区域降水线十分接近,表明其水团主要来源为大气降水;同时长江和支流库湾中的氘盈余与建库前有明显不同,说明三峡水库蓄水之后长江干流和支流库湾水体组分发生了一定改变;支流库湾中水体混合比存在明显的时空变化,长江干流水团占的比例为76. 9%~99%。     

Effects of pool formation and flash flooding on relative abundance of young‐of‐year flannelmouth suckers in the Paria River,Arizona

Flannelmouth sucker, Catostomus latipinnis, a fish endemic to the Colorado River basin in the western United States, appears to experience poor recruitment to adult size in the Colorado River, downstream of Glen Canyon Dam. Lack or impermanence of rearing areas for young‐of‐year (YOY) fish is hypothesized to be the problem. Knowing the importance of tributary mouths as rearing areas in other river systems, we studied use of the mouth of the Paria River, a tributary of the Colorado River, by YOY flannelmouth suckers, and the availability of rearing area in the mouth at different flow levels in the Colorado River in 1996 and 1997. We also examined the relationship between flash floods in the Paria River and catch‐per‐unit‐effort (CPUE) of YOY in the Paria River between 1991 and 1996. Maximum mean daily discharge in the Paria River was inversely correlated with CPUE of YOY flannelmouth suckers (Spearman Rho=?0.9856, p=0.0003) during their critical rearing period (15 March–30 June). Thus, it appears that YOY flannelmouth suckers rear longer in the Paria River in years when flash flooding is minimal. Recruitment of YOY flannelmouth suckers at the Paria River may also be improved by enhancing pool formation during spring and summer rearing seasons. YOY flannelmouth sucker was captured in a pool created by high Colorado River flows (≥336 m³/s) that inundated the mouth of the Paria River during spring and summer, 1996. In 1997, high flows (about 550–750 m³/s) in the Colorado River during winter and spring initially inundated the Paria River and formed a pool in the mouth. However, these high flows eventually caused 0.5–1.0 m of suspended sediment from the incoming Paria River to deposit in the mouth. Thus, despite higher flows than 1996, the slackwater area formed only occasionally in 1997. Differences in pool formation between 1996 and 1997 demonstrate that pool formation cannot be inferred solely from Colorado River flows. Copyright © 2001 John Wiley & Sons, Ltd.     

MSR（ITU-T X.87/Y.1324）体系构架与系统特性

针对光城域网对综合业务的电信级需求，以城域网三网业务融合传送为主要领域，以基于弹性分组环RPR实现多业务传送为主要手段，研究了多业务传送与交换的简化方法，介绍了自主国际标准ITU-T X．87／Y．1324的协议要点、组网拓扑结构、传输架构、系统节点的组成和MSR通用帧格式。通过与RPR的比较，得出如下结论：MSR解决了语音、数据和视频等多业务(支路)分别在RPR各节点上，下的传送、支路组播、支路保护和性能监测问题。MSR成本较低，而且在同一网络平台上提供语音、数据和视频等支路业务需要这样的功能，它是目前基于分组的城域网多业务传送和出租的有效方法。     

平原河道支流水量交换数值模拟方法

简要介绍了4种平原河道支流水量交换的模拟方法，即干支比法、调蓄滩地法、调蓄单元法和反分析求解法．并应用这4种模拟方法分别计算了苏州河与黄浦江的水量交换．其结果表明，调蓄单元法和反分析求解法具有较高的模拟精度．     

河流支流入河口水质处理系统工程设计初探

为了改善流溪河水体水质,通过设计膜生物反应器-人工湿地组合工艺系统,来提高流溪河支流入河水质。根据支流入河口的地理位置,在支流的末端建造3个污水拦截坝,将污水依次截留形成两个处理阶段.系统设计利用了水位差为水流提供动力,充分利用生物膜法占地面积小、处理效率高、操作简单及对CODcr、SS、NH3-N、微生物的去除效果好,并结合了人工湿地技术具有生态、廉价、较高的N和P去除率、易于管理的优点。     

基于系列水沙条件的黄河内蒙段河床演变试验研究

为了探讨系列径流泥沙过程对河床演变的累积效应,对黄河内蒙三湖河口-昭君坟河段,进行了5种不同系列年水沙过程的河床演变试验研究.规划整治工程方案因归顺河势,有效减少了主槽淤积;调水方案流量Q＜ 400m3/s出现几率低,有效减小了小水淤积.不同方案累积淤积量还与高含沙支流洪水的入汇几率有关,入汇次数多,淤积量大;同时也对模拟河段局部纵剖面演变有重要影响.当水沙系列过程使得小流量过程占优时,河相关系(√B)/H增大,平滩流量降低;数据分析表明汛期来沙系数S/Q与河相系数(√B)/H间存在对数型关联性,说明汛期水沙条件是影响河道断面形态的重要因素.     

支流来水来沙对黄河宁蒙河段冲淤的影响

采用实测资料分析和数学模型计算等多种手段分析了支流来水来沙对宁蒙河段淤积的影响。结果表明:宁蒙河段支流来沙量与干流淤积量的相关性较强,是影响宁蒙河段淤积的主要因素之一;考虑支流来水来沙与不考虑支流来水来沙相比,宁蒙河段年均多淤积0.301亿t,1986年以前年均多淤积0.207亿t,1986年以后年均多淤积0.377亿t。