山区卵砾石河流的阻力

山区卵砾石河流在西部山区广泛分布,其阻力关系是认识水流泥沙输移规律、模拟山洪演进过程的制约因素。通过在四川龙溪河的现场观测,获得了水力学、泥沙、地貌等要素的数据,分析了阻力系数与卵砾石特征粒径、坡降、流量、河床结构强度等参数的关系,检验了已发表的多个山区河流阻力公式的适用性。结果表明,由于山区卵砾石河流存在不同发育程度的河床结构以及卵砾石的部分可动性,阻力系数与山区河流的流量、坡降、河床结构发育程度参数等有密切关系;Rickenmann 及 Ferguson 阻力公式在龙溪河具有较好的适用性。本文仅仅是山区河流阻力的初步成果,今后将进一步开展阻力关系的深入研究。     

大比降卵砾石河流输沙率试验研究

针对我国西部地区大比降卵砾石河流的比降和河床组成,采用1m宽水槽对大比降卵砾石河流的输沙率进行分析研究。分析结果表明：（1）水槽试验数据与现有推移质公式对比,比较有代表性的Meyer-peter（1948）、Engelund（1976）两个公式计算的输沙率偏大,与Ackres＆White（1973）公式计算值较为接近。（2）根据Ackres＆White（1973）的结构形式,补充大比降卵砾石河流泥沙起动条件,假设推移质运动强度与水流有效运动强度成幂次关系,得到大比降卵砾石河流输沙率公式形式。（3）通过水槽试验数据,拟合出适合大比降卵砾石河流的输沙率公式。     

砂卵石河流粗化完成后细沙补给对河床阻力的影响

结合Venditti关于细沙补给对河床活动性影响的分析,引用修正后的Einstein-Barbarossa方法对河床阻力进行划分,探讨了细沙补给对砂卵石河流冲刷粗化完成后河床阻力变化的影响。研究结果表明:在一定量细沙补给的条件下,沙粒阻力与床面阻力的比值先减小后增大,形状阻力与床面阻力的比值先增大后减小;水流克服表面阻力损失的能量随沙粒阻力减小而减少,进一步导致水流损失的机械能减小,河床上大颗粒泥沙获得的能量增大进而导致其活动性增强;河床上活动的泥沙颗粒与裸露大颗粒泥沙之间不断接触碰撞形成局部能量交换,裸露大颗粒泥沙通过水流方向的动量交换所产生的颗粒剪应力增大,这可能也是河床上大颗粒泥沙活动性增强的一个原因。     

山区河流河床形态对推移质输沙率影响的试验研究

为探索山区卵砾石河流推移质运动受水流条件和河床形态的影响规律,开展了大比降浅水流动条件下卵砾石输移的室内水槽试验,获得了两组泥沙组成的19个流量条件下的水流、泥沙及河床三维地形场数据。结合室内水槽试验及文献中的天然河流输沙观测数据,分析了不同水沙输移阶段水流阻力、河床形态与推移质运动之间的关系。试验结果表明:河床阻力系数随着河床形态强度参数增大而增大,形态阻力与河床形态强度参数相关性更强。在泥沙补给充分阶段,推移质输沙率与床面阻力、形态阻力及河床形态强度参数均呈正相关关系;在泥沙补给不充分的水流冲刷阶段,推移质输沙率随河床形态强度参数增大而减小。     

基于图像识别的非恒定流卵砾石输移试验研究

采用自主研发的水位、泥沙运动同步观测系统,分析相同幅度、不同周期非恒定流条件下卵砾石起动试验研究,其中水位与泥沙运动观测系统主要由相机、超声水位计组成。提出了卵石运动图像的分析方法,能够有效识别经过断面的卵石运动。初步对非恒定流条件下卵砾石输移进行研究,试验结果表明,非恒定流条件下,上升段输沙强度大于下降段输沙强度,随着周期的增加,上涨段与下降段的输沙强度差逐渐减小。     

HEC-RAS模型在山区中小河流水面线计算中的应用研究 ——以铁场河综合整治工程为例

山区中小河流具有坡降大、水工建筑物多、水流急的特点,在水面线推算上相比平原区河流难度较大。常规的水面线方法在急流及多水工建筑物情况下容易出现突变,需分段推求水面线,计算精度较差。该文选定铁场河综合整治工程案例,建立HEC－RAS一维模型推算铁场河干流水面线,并与常规的水面线方法结果对比,分析HEC－RAS模型在山区中小河流水面线推算中的优点。     

山区河流二维推移质数学模型及应用研究——以望谟河整治工程为例

为了充分利用我国西南山区丰富的水能资源,同时减少望谟河因山洪引起的高含沙水流洪涝和泥石流灾害,应用二维水流泥沙数学模型常用的控制方程式,采用有限体积法对方程进行离散,并使用"冻结法"对模型中陆地边界进行处理,建立了具有一定通用性的山区河流的二维推移质数学模型。利用建立的模型对贵州省望谟河新屯段进行了流场和推移质冲淤模拟计算,并进行了望谟河整治工程影响分析。结果表明:对于望谟河水位和河床冲淤变形验算,数值模型计算值与经验公式推算变化趋势一致,数值也较为接近;整治工程实施后望谟河沿程的水位绝大部分发生不同程度的降低,仅局部存在微小的抬高;望谟河整治后,同流量下,水位降低,流速归槽泥沙淤积减小,有利于河道防洪。     

山区型水利发展与改革探讨——以曲靖市为例

本文通过调查数据深入分析了曲靖市水利发展与改革现状,指出其水资源供需矛盾突出、管理体制不完善、经费投入不足、工程建设管理滞后等主要问题,最后提出了加快水利发展与改革的措施建议。     

山区小城镇最终规模控制法——以松滋市刘家场镇总体规划为例

本文通过对我国山区小城镇的特点、发展的不确定性、最终规模的可预见性等一系列因素的剖析,指出我国现行小城镇规划方法的局限性;提出了我国小城镇总体规划中符合山区小城镇实际的最终规模控制法。     

山区河道堤防设计探索——以松阳县河道治理工程为例

针对山区河道的特点,结合山区河道堤防工程实例,探讨山区河道堤防工程设计的一般原则与方法,并提出山区堤防工程应在确保防洪安全的前提下,合理布置堤线,充分发挥山区自然优势,就地取材,采用合适的断面型式及生态护坡,使山区堤防工程建设更科学、合理、实用。     

Flow regulation by dams affecting ichthyoplankton: the case of the Porto Primavera Dam,Paraná River,Brazil

The effects of a dam closure (Porto Primavera Dam) on reproduction of the main species that use the floodplain located below a nursery area were determined. Specifically, we examined, before and after the closure of the dam, the spatial distribution of larvae and the differences in density according to life strategy (migratory and non‐migratory species). Fifteen points distributed along the channels of the Paraná, Ivinheima and Paranapanema rivers were sampled, between 1997 and 2001, (October 1997 to December 1998—pre; and between January 1999 to March 2001—post closure), during the spawning period of most fish species found in the region (October to March). Samplings were always conducted at night, using a conical‐cylindrical plankton net (0.5 mm mesh) with a flowmeter attached. There were significant differences in larvae densities between pre and post dam closure for several species. Also, there were significant differences between the pre and post‐closure periods for densities of migratory and non‐migratory species, and between sampling sites. These findings indicate decline in densities and number of taxa caught after the closure of the dam. Larvae of migratory species, formerly common in the entire study area, were registered only in points influenced by the non dammed rivers (such as the Ivinheima River), indicating that the closure of Porto Primavera caused negative impacts on fish reproduction downstream of the dam. Copyright © 2006 John Wiley & Sons, Ltd.     

堵汊工程在长江中下游分汊河道整治中的作用

为了控制河势，防害兴利，在长灌中下城陵矶至江阴河段的４１处分汊河道进行堵汊，实施后未对长江河道带来不利影响，而且这工程在防洪、防止崩岸发展、消灭钉螺、稳定河势、航运、洲滩利用等方面发挥了积极的作用。实践证明：对长江中下复杂多汊整治应堵塞分流比较小的支汊，使多汉型河道向两汊型方向转化，对分汊河道的稳定十分有利。     

塔里木河“二源一干”生态供水潜力研究

为解决塔里木河干流水资源短缺、流域损失水量过大、用水效率低下、农业灌溉用水挤占生态用水等问题,基于“节水优先”的治水方针,以塔里木河二源流(阿克苏河、叶尔羌河)及其干流(“二源一干”)的山区水库群和平原水库群为研究对象,兼顾塔里木河干流的农业灌溉用水、生态用水、工业用水、生活用水等多目标,构建并求解了现状水平年和远景规划年的山区与平原水库群联合调度优化模型,分析了塔里木河干流的生态供水潜力和山区水库群联合调度的贡献。结果表明：仅通过干流平原水库群联合调度,农业灌溉用水和生态用水的供水保证率难以满足设计要求;通过山区与平原水库群优化调度,在远景规划年各行业均满足设计保证率要求,体现了山区水库群显著的调控性能和“节水优先”治水方针的合理性和可靠性;远景规划年塔里木河干流的生态供水潜力为2.84亿m³,可为塔里木河下游生态保护与修复提供了坚实的水量基础。     

Rate of biotic colonization following flow restoration below a diversion dam in the Bridge River,British Columbia

In August 2000, a continuous flow release was initiated below a diversion dam in the Bridge River, British Columbia, to rewater 4 km of stream bed that had been without flow for 37 years. Within a month after the start of flows, periphyton and invertebrate populations were present in the previously dry reach. Juvenile salmonids were common downstream of the rewetted reach, but only a few moved upstream to the new habitats after flow restoration. However, adult salmon quickly colonized the rewetted area and spawned 1–8 months after the onset of flow. Age‐0 salmonid abundance was high 1 year later and appeared to be largely due to successful spawning in the new reach rather than the upstream migration of juveniles. We conclude that the full colonization of the new reach will take more than a year as a consequence of the migratory patterns of the salmonids species in the river, and that monitoring programs for habitat restoration should be cognizant of the lags in the response of target populations because of their life histories. Copyright © 2008 John Wiley & Sons, Ltd.     

基于大辽河上游水库来水与压盐流量关系的研究

根据大辽河上游水库的来水量,通过对营口境内历年灌区各提水站的实际提水量比较,经过分析从而得出压盐流量与水库来水之间的关系。其结论为：大辽河槽内必须保持淡水7000～9000万 m3,才能保证压盐流量至田庄台,两岸才能正常引水。水稻泡插期严重缺水年份,大辽河盐分太高,水库加大放流压盐效果明显。     

Influence of Flow on Community Structure and Production of Snag‐Dwelling Macroinvertebrates in an Impaired Low‐Gradient River

The natural flow regime of rivers has been altered throughout the world in a variety of ways, with many alterations resulting in reduced flows. While restoring impaired systems remains a societal imperative, a fundamental understanding of the effects of reduced flows on river ecosystem structure and function is needed to refine restoration goals and guide implementation. We quantified the effects of chronic low flows on snag‐dwelling macroinvertebrate community structure and production in a low‐gradient river. Macroinvertebrates commonly associated with flowing water (e.g. passive filter‐feeders (PFF)) and higher quality habitats (e.g. Ephemeroptera, Plecoptera and Trichoptera (EPT)) had significantly higher abundance and biomass, and showed trends of higher production, in faster flowing reaches upstream of a hydrologic disconnection created by a drainage ditch. The presence of EPT and PFF groups resulted in a significantly more diverse community composed of larger‐sized individuals compared with downstream, low‐flow reaches, where smaller‐bodied taxa (e.g. small crustaceans), and groups reflective of degraded conditions (e.g. Oligochaeta, Isopoda and Chironomidae) dominated production. Multivariate analyses suggested that differences between these two disparate communities were driven by water velocity and organic matter resources. Mean estimates of total community production did not differ significantly between the two reaches, however, there were areas in low‐flow reaches that attained high secondary production because of patchily distributed and highly productive chironomids. Results demonstrate that long‐term reductions in flows, even in a low‐gradient river, can lead to significant shifts in macroinvertebrate communities, ultimately influencing energy flow pathways in stream food webs. Copyright © 2015 John Wiley & Sons, Ltd.     

宁夏黄河干流和干支流交汇处河床冲淤演变分析

分别采用沙量平衡法和断面法计算宁夏黄河干流和干支流交汇处的冲淤量,以刘家峡、青铜峡水库运行前(1951-1968年)、刘家峡、青铜峡水库运行后(1969-1985年)、龙刘联合运用(1986-2005年)和近期(2006-2011年)四个阶段对干流的冲淤变化进行了研究,对干支流交汇处1993-2015年历次实测大断面资料进行套绘,分析了1993-2015年干支流交汇处的断面特征变化以及干、支流不同水沙组合对干流和干支流交汇处冲淤的影响。分析结果表明:宁夏黄河干流年均来沙系数越大,干流河床淤积越严重,但支流来沙量的增大对干流河床冲淤的影响不大;干支流交汇处年均全断面冲淤量与干流年均来沙系数无明显相关关系;支流年均来沙系数越大,干支流交汇处断面反而冲刷越严重。     

黄河小北干流河段揭河底规律分析

“揭河底”现象是黄河高含沙洪水特有的一种泥沙运动方式.本文通过对历史“揭河底”水文资料的统计和分析,提出了历史“揭河底”发生的水沙条件、河道边界条件、河床淤积物组成,总结了其发生的规律.该研究进一步探讨了黄河小北干流河段“揭河底”冲刷现象的运动机理,充分发挥冲刷塑造窄深河槽的积极作用,减小了冲刷造成的危害,对在治黄中如何利用“揭河底”规律,趋利避害有一定的指导意义.     

流域环境流量管理分区方法研究——以浑河流域为例

环境流量管理分区对识别流域各地区的环境流量管理要求,合理配置河流环境流量,协调社会-生态竞争性用水具有重大意义。本文结合管理结构体系,统筹考虑社会-自然两大属性,构建流域分区指标体系;利用聚类分析算法以及布尔运算法结合指标体系对管理流域进行划分,建立了一种区划管理分区的方法。以浑河流域为例,按划分方法将浑河流域划分为5个环境流量管理分区。结果表明:分区方法切实可行,利于简化流域整体管理复杂程度;每个分区具有独立完整的管理结构体系;环境流量管理分区特征鲜明,利于各区管理目标的制定。