补偿中华鲟产卵场水动力环境的梯级水库联合生态调度研究

三峡—葛洲坝梯级水利枢纽工程的建设和运行阻隔了长江部分洄游鱼类的洄游通道,梯级水库的联合调度运行改变了坝下河道天然径流过程,对被迫在坝下形成新产卵场的珍稀水生物中华鲟的产卵繁殖产生一定影响。为有效保护中华鲟资源,在明确梯级水库调度运行与中华鲟产卵场产卵适合度相关性分析的基础上,提出优化三峡下泄流量和葛洲坝运行方式相结合的三峡—葛洲坝梯级水库生态调度方式,以补偿中华鲟产卵栖息所需的河流生境。通过以三峡水库的实际来流过程输入水库生态调度模型,得出中华鲟产卵期(每年10—12月)补偿其产卵栖息水环境的梯级水库联合生态调度方式。根据梯级水库生态调度与现有调度结果进行分析比较结果表明:梯级水库联合生态调度可在满足三峡水库常规调度目标的基础上同时满足中华鲟产卵所需的生态流量,配合葛洲坝电厂优化调度运行方式,可有效增加坝下中华鲟产卵场水动力环境产卵适合度,补偿梯级水库运行对中华鲟产卵生境造成的不利影响。     

优化中华鲟产卵生境的水库生态调度研究

为减轻水利工程对河流生态系统造成的不利影响，针对重要珍稀水生动物中华鲟资源的有效保护及和可持续发展问题，本文在葛洲坝下游中华鲟产卵场水动力数学模型及产卵适合度评价模型的基础上，利用BP人工神经网络的学习能力获得水库调度与产卵场产卵适合度关系模型，并将关系模型嵌入葛洲坝现行的水库调度模型，获得中华鲟产卵期（10~11月）优化中华鲟产卵生境的水库生态调度模型。生态调度模型以中华鲟产卵场产卵适合度及水电厂发电量最大为双目标函数，以同期水库需满足的航运效益、水资源利用效益及水轮机运行效益为主要约束条件。通过比较相同入库流量下生态调度和现行调度的水库综合效益，得出在中华鲟产卵期，优化中华鲟产卵生境的生态调度在仅损失0.15%发电量的同时使坝下中华鲟产卵场产卵适合度增加39%，使中华鲟获得更适宜的水动力环境，增加产卵概率，有效保护中华鲟资源。     

中华鲟产卵场的三维水流特性分析

中华鲟面临严重的种群资源问题,明确中华鲟产卵场的水流特性可为产卵场修复和自然种群挽救提供更准确合理的技术参数。研究运用流体力学软件Fluent模拟葛洲坝坝下中华鲟产卵场产卵时期的三维水流过程,分析流速、涡量、湍动能等水力学参数在产卵场不同功能区内的变化规律和取值范围。结果表明:不同功能区水力学参数的取值范围不同,对比各取值范围发现底层流速基本满足产卵受精区播卵区着卵孵化区,而播卵区的流速垂向变化幅度总体大于产卵受精区;涡量基本满足播卵区产卵受精区着卵孵化区;湍动激烈区基本位于水体的上中层,底层湍动能在各功能区变化不大,特别是着卵孵化区的湍动能没有明显区别于播卵区。葛洲坝坝下产卵场水流状况不是特别有利于中华鲟卵的受精散播和附着孵化,为了进一步明确中华鲟产卵繁殖的水流特性,需要继续开展大量的模拟、对比分析工作。     

优化中华鲟产卵场水动力环境的梯级水库联合调度研究

为保护中华鲟资源,修复其产卵场水动力环境,通过资料调查、数值模拟等方法,明确三峡-葛洲坝梯级水库联合运行前后葛洲坝下中华鲟产卵场水动力环境演变趋势,构建优化中华鲟产卵场水动力环境的梯级水库联合调度模型。对比分析2010年中华鲟产卵期(10—12月)梯级水库实际调度过程与优化调度,得出结论:三峡-葛洲坝联合优化调度方案在满足梯级水库常规调度目标的同时,可有效提高中华鲟产卵场产卵适合度,优化产卵场水动力环境,增加中华鲟自然繁殖的概率,有效保护中华鲟资源。     

葛洲坝电站运行对中华鲟产卵场水流条件的影响

葛洲坝修建后,中华鲟被迫于每年10~11月在葛洲坝下游产卵繁殖。但三峡水库蓄水后,中华鲟产卵期,葛洲坝来水量减小,使中华鲟产卵场水流条件发生变化,从而对其自然繁殖产生不利影响。通过建立中华鲟产卵场二维水动力模型,在探讨中华鲟产卵场适宜水流速、流量和葛洲坝机组增容的基础上,提出2种葛洲坝水电站生态优化调度方案。结果表明:改变发电流量泄流位置将一定程度改善中华鲟产卵场水流条件,但增加机组额定发电流量对改善产卵场水流条件作用有限。     

三维水动力学数值模拟获得中华鲟偏好流速曲线

偏好流速是描述鱼类行为的重要特征量,是建立鱼类行为与栖息地水力特性关系的桥梁。中华鲟是我国重要的珍惜鱼类,由于其体形庞大,在实验室获得其偏好流速非常困难。同时由于其底栖性,在自然界中获得其活动位置附近微栖息地的流速特征也非常困难。自从葛洲坝1981年大江截流后,原本洄游到上游进行繁殖的中华鲟被阻隔在葛洲坝以下,并在葛洲坝下狭小的水域中进行自然繁殖。本文使用三维数值模拟方法模拟此河段的流场特征,并结合1998年到2002年间在此河段进行的声纳探测结果获得中华鲟的偏好流速。     

CALCULATION OF FLOW FIELD AND ANALYSIS OF SPAWNING SITES FOR CHINESE STURGEON IN THE DOWNSTREAM OF GEZHOUBA DAM

The Chinese sturgeon (Acipenser Sinensis) is one of the unique and important fishery resources in China. Since the construction of the Gezhouba Dam, the traditional migration route of the sturgeon has been blocked; consequently, the length of natural spawning sites is reduced from 800 km in the past to less than 5 km at present. As an endangered species, the Chinese sturgeon has become one of the most conserved aquatic species. In this article, the flow field of its spawning states in the downstream of Gezhouba Dam was simulated and analyzed using N-S equations and k ? ε turbulence model. Volume Of Fluid (VOF) method with the Finite Volume Method (FVM) was used to simulate the water-air two-phase flow to examine the computed area. On the basis of the ecological-hydraulic characteristics of Chinese sturgeon, the features of the flow field were investigated to provide theoretical support for the proper management of the Three Gorges Reservoir.     

三峡大坝至葛洲坝两坝间河段通航水流条件

采用水流数学模型对三峡大坝至葛洲坝两坝间河段的通航水流条件进行研究,结果表明,枯水期日调节条件下两坝间河段的水面比降和流速变化均不影响本河段万吨级船队的航行条件。洪水期间大流量条件下两坝间航道水流条件十分复杂,在葛洲坝坝前水位为66.00 m、流量大于30 000 m3/s时,两坝间的水流条件不能满足现状条件下万吨级船队的通航;随着流量的增加,通航卡口段也随之增加,主要位于水田角、喜滩上下、石牌、偏脑等局部河段。研究成果可为两坝间航线选择与航道治理提供参考。     

三峡水库对下游水力学要素的影响

文章模拟计算了三峡水库建库前后,葛洲坝下游中华鲟产卵场水力学要素的变化,并对模拟结果进行分析.结论表明:三峡水库建坝后各水力学要素,如流速、过水面积、弗劳德数、切应力等水力学参数都有不同程度的减小,从而改变了原有河流生态系统的平衡.根据对2003年后中华鲟产卵次数及数量的观测表明,以上变化可能对中华鲟的繁殖产生一定的影响.     

四大家鱼产卵栖息地适宜度与大坝泄流相关性分析

为探究三峡—葛洲坝水库联合调度运行后,长江四大家鱼对不同大坝泄流工况下产卵栖息地水动力环境的适宜性,在构建长江四大家鱼主要产卵栖息地水动力数学模型及产卵栖息地适宜度评价模型基础上,针对大坝不同运行参数进行大坝泄流方式与四大家鱼产卵栖息地适宜度相关性分析。结果表明,大坝泄流量为10 000~15 000 m~3/s时,四大家鱼产卵栖息地具有较高的适宜度;在流量基数为10 000~15 000 m~3/s,日均流量增长率为1 000~1 500 m~3/s时,四大家鱼产卵栖息地同样有较高的产卵栖息适宜度。研究结果可为构建考虑家鱼自然繁殖的水库生态调度方式提供参考。     

Applying instream flow incremental method for the spawning habitat protection of Chinese sturgeon (Acipenser sinensis)

The Chinese sturgeon, Acipenser sinensis, is an anadromous species that spawns in the Yangtze River and Pearl River of China. Its population has declined dramatically since the construction of the Gezhouba Dam (GD) in 1981 and then with the impoundment of the Three Gorges Dam (TGD) upstream of the GD in 2003. This paper presents a quantitative method based on the instream flow incremental method to explore the relationship between the fish spawning habitat and the operations of the GD and TGD, aiming to find a solution for conservation of the species. A two‐dimensional hydrodynamic model was built with the River2D to simulate the hydraulic behaviour of the stream below the GD. Habitat suitability index was determined by the biological data of the fish collected in the field. The two parts were then integrated through a geographical information system developed via ArcGIS to outline the fish habitat area variation with flows. The decision support system is applied to set up a habitat time series for validating the assumption that more habitats have the potential to support more fish. The fish habitat results for alternative instream flow schemes are then compared with one another for defining the optimal flow requirements and evaluating effects of reservoir operation alternatives in order to improve the operation management for the GD and TGD projects. The results show that the optimal flow for spawning of the fish is about 7000–13000 m³/s and the optimal inlets combination is where the inflow comes from two power plants. Copyright © 2009 John Wiley & Sons, Ltd.     

Genetic origins and diversity of lake sturgeon in the St. Louis River Estuary

Lake sturgeon Acipenser fulvescens were extirpated from the St. Louis River Estuary (SLRE) by the early 1900’s due to overfishing and habitat degradation. A restoration stocking program began in 1983, and continued almost annually until 2000. Lake sturgeon stocked into the SLRE were primarily obtained from the Wolf River (Lake Winnebago) genetic stock (n = 861,000) but some sturgeon were obtained from the Sturgeon River (Lake Superior) genetic stock (n = 61,380). Recently, spawning and natural recruitment has been documented near the Fond du Lac Dam, the upstream limit for lake sturgeon migrating from Lake Superior. However, the genetic origin of lake sturgeon spawning in the SLRE was unknown. Our objectives were to determine (1) the genetic origins and (2) genetic diversity of lake sturgeon spawning in the SLRE. Using both GENECLASS2 and ONCOR, a majority (79–81%) of lake sturgeon captured in the SLRE during spawning (2016–2018) assigned to the Wolf River genetic stock (Lake Winnebago) with greater than 80% probability using established microsatellites and a standardized genetic baseline. Other genetic stocks present (≥1%) included the Pic and Goulais rivers and possibly the Black Sturgeon River (identified using GENECLASS2, but not ONCOR); no fish assigned to the Sturgeon River using either method. Genetic diversity metrics showed that the SLRE lake sturgeon population was similar to other Lake Superior lake sturgeon populations. Overall, the SLRE Sturgeon population appears headed towards recovery. Adaptive management practices currently being employed should be continued to help guide further recovery of this population.     

三峡大坝与葛洲坝两坝间水域的水环境保护

剖析三峡大坝与葛洲坝两坝之间的水环境状况。分析给出建坝前两坝间的水环境状况,以及葛洲坝建坝后的水污染状况,对黄柏河流域进行总体水质评价,并给出分段水质评价。最后建议,对两坝间的水域水环境治理、流域生态治理,应纳入总体规划和三峡工程专项治理和保护项目中,对排污口和污染源进行规范化治理,对黄柏河下游河段实行污染物总量控制,对葛洲坝水利工程建议开展工程环境影响评价项目后评估工作。     

航道整治水文情势变化对四大家鱼产卵场的影响——以荆江周天河段为例

以长江中游荆江周天河段航道整治工程为例,采用平面二维水动力数学模型,对工程修建后水流流态、水位和流速等水力因素变化进行计算分析,进而研究航道整治工程所导致的水文情势变化对河段内四大家鱼产卵场的影响。研究表明:工程实施后,产卵期水位变化约-0.01～0.01 m,流速变化约为-0.10～0.15 m/s,不会对产卵场水流流态造成大的影响;潜丁坝工程会导致局部流速以及附近河床冲淤的变化,但客观上起到了人工鱼礁的作用,为鱼类提供良好的庇护、栖息及觅食等环境,一定程度上有利于鱼卵的受精和正常孵化;工程水下沉排和抛石使得局部河床地形更为复杂,但对河床地形地貌影响范围和程度较小。     

基于水力学模型的三峡库区四大家鱼产卵场推求

卵场位置是长江流域四大家鱼资源调查的重点。对于四大家鱼产卵场位置的定位以及影响家鱼产卵繁殖的水文、水流条件等非生物的因素,一般以河段邻近水文站观测数据来推算或近似。本文采用MIKE 11商业软件,基于三峡库区622个河道断面,模拟了2002~2003年三峡库区水动力变化,而后以重庆市云阳断面为起点,根据该断面2002~2003年四大家鱼捞获卵、苗的发育时间,推求出长江上游重庆至云阳4个产卵场的位置,最后对模型法推求产卵场位置的不确定性进行了分析。     

水质模型中污染物衰减系数敏感性分析

对于河流纳污能力数值模拟问题,污染物扩散衰减系数是一个重要参数,决定了模型的准确性和可靠性。本文针对三峡大坝至葛洲坝之间河段,基于Mike21建立平面二维水质模型,以氨氮为典型污染物分析河流纳污能力,在此基础上进行了衰减系数对流量、本底浓度及有无衰减过程等因素的敏感性分析。模拟结果表明:相比本底浓度,流量的改变对污染物扩散过程的影响更为明显;污染物扩散范围随流量的增加而增加,随本底浓度的增大而降低;增大衰减系数将使污染物扩散范围减小,且高流量低本底浓度时衰减系数的取值范围较大,使得影响范围变幅最大。     

Genetic assessment of straying rates of wild and hatchery reared lake sturgeon (Acipenser fulvescens) in Lake Superior tributaries

Natal philopatry in lake sturgeon (Acipenser fulvescens) has been hypothesized to be an important factor that has lead to genetically distinct Great Lakes populations. Due to declining abundance, population extirpation, and restricted distribution, hatchery supplementation is being used to augment natural recruitment and to reestablish populations. If hatchery-reared lake sturgeon are more likely to stray than naturally produced individuals, as documented in other well-studied species, outbreeding could potentially jeopardize beneficial site-specific phenotypic and genotypic adaptations. From 1983 to 1994, lake sturgeon propagated using eggs taken from Lake Winnebago adults (Lake Michigan basin) were released in the St. Louis River estuary in western Lake Superior. Our objective was to determine whether these introduced individuals have strayed into annual spawning runs in the Sturgeon River, Michigan. Additionally, we estimated a natural migration rate between the Sturgeon River and Bad River, Wisconsin populations. Presumed primiparous lake sturgeon sampled during Sturgeon River spawning runs from 2003 to 2008 were genotyped at 12 microsatellite loci. Genotypic baselines established for the Sturgeon River (n = 101), Bad River (n = 40), and Lake Winnebago river system (n = 73) revealed a relatively high level of genetic divergence among populations (mean F_ST = 0.103; mean R_ST = 0.124). Likelihood-based assignment tests indicated no straying of stocked Lake Winnebago strain lake sturgeon from the St. Louis River into the Sturgeon River spawning population. One presumed primiparous Sturgeon River individual likely originated from the Bad River population. Four first-generation migrants were detected in the Sturgeon River baseline, indicating an estimated 3.5% natural migration rate for the system.     

Seasonal use of two unregulated Lake Superior tributaries by lake sturgeon

Lake sturgeon movement in two adjacent unregulated Lake Superior tributaries, the Pic and White rivers, was assessed over several years to determine seasonal use, identify potential contributing factors for entry or exit migrations, and evaluate whether sturgeon using these tributaries constituted one or two populations. A total of 95 lake sturgeon implanted with radio transmitters were tracked using multiple stationary receivers augmented with boat-based manual surveillance during peak movement times. Both rivers were used by lake sturgeon during the open water (“ice off”) season. In general, spawning sturgeon moved to the first insuperable barrier (i.e., natural rapids) during the spawning season, and then moved downstream to deeper pools in mid- to late summer. Non-spawning sturgeon moved into the river concurrently but remained in lower portions of the river. Lake sturgeon emigrated from the Pic River and resided in Lake Superior during the winter season whereas a small portion of radio transmittered sturgeon, originally sampled in the Pic River, overwintered in the White River. River discharge and the interaction between discharge and water temperature were correlated with upstream movement, and river discharge was also correlated with outmigration. No genetic structuring was apparent between Sturgeon within the two rivers, consistent with telemetry data showing radio-tagged fish moving readily between the rivers. This study provided pertinent seasonal use information of unregulated Great Lake tributaries and may contribute to planning processes for future hydroelectric developments to minimize disruptions to lake Sturgeon populations.     

提高三峡-葛洲坝两坝间通航能力试验研究

三峡-葛洲坝两坝间河段是川江船舶航行最困难的航段之一.葛洲坝建成后,当川江流量小于2万 m 3/s,航行条件较好;当川江流量大于2万m 3/s,两坝间洪水急流滩相继出现,航行条件逐渐变差.各主要滩段均不能满足万吨级船队的通航要求.因此,提高两坝间河段通航流量,延长通航期具有重要意义.采用增加推轮推力,改善推轮操纵性能和减驳减载等改进措施,可将两坝间河段的通航流量级由上水的2万m 3/s提高到4.5万m 3/s.     

上游水库水温情势变化对中华鲟产卵江段水温的影响

针对三峡水库蓄水运行后中华鲟自然产卵期逐渐推迟的问题,对影响中华鲟繁殖关键要素水温的因素开展研究。基于三峡大坝及葛洲坝上下游典型断面的水温及气温实测资料,分析了三峡水库蓄水后10年(2003—2012年)的水温变化情势和影响葛洲坝下游中华鲟产卵江段特定时段水温的原因。结果表明:三峡水库蓄水后库区在10月水温高于蓄水前,对下游中华鲟产卵江段水温产生直接影响;局地气温变化与水温情势变化密切相关,是引起中华鲟产卵江段水温上升的根本原因,对水温上升的贡献度约为61%。