Historical overview of the efficacy of two decades of power plant fisheries impact assessment activities in Chesapeake Bay

The Chesapeake Bay is world renowned as an estuary that historically yielded large harvests of a wide variety of fish and shellfish species. Thirteen power plants are located on the mainstem of the Bay and its tributaries in Maryland, drawing out of and discharging into the Bay eight billion gallons per day of the Bay’s waters for cooling purposes. Maryland DNR’s Power Plant Research Program (PPRP) has, since 1974, funded a wide variety of fisheries assessment, entrainment and impingement studies. PPRP’s Potomac River Fisheries Program (PRFP) encompassed multi-year, statistically rigorous, quantitative studies of all life stages of striped bass, from egg to adult, together with estuarine hydrodynamics modeling and water quality assessments, all yielding data integrated to project potential entrainment impacts from a proposed nuclear power plant. PPRP and utility-sponsored monitoring programs at BGE’s Calvert Cliffs NPP, PEPCO’s Chalk Point SES and DP&L’s Vienna SES, as well as other generating facilities throughout the state have provided comprehensive data on impingement, entrainment and receiving water populations of all life stages of potentially impacted resource species. These studies have resulted in unusually complete and long term data sets being available for impact assessment applications, and provide a basis for confirming and validating impact assessment findings and conclusions based on much shorter time series. The state/federal Chesapeake Bay Program has extensively characterized the status and trends of all important resource species in the Bay. We compare and contrast impact conclusions and projections from studies conducted in the 1970s and 1980s with current data and information on the status of and trends in affected fish stocks in Chesapeake Bay. We use that comparison to establish the role that power plant impacts play as factors driving changes in species abundance over time. These comparisons and contrasts between historical and current data and information also illustrate and confirm the methodologies that have proven to be most and least useful for assessing entrainment and impingement impacts.     

Florida Power Corporation–Anclote Power Plant Entrainment Survival of Zooplankton

Florida Power Corporation (FPC) owns and operates the Anclote Power Plant at the mouth of the Anclote River on the Gulf of Mexico near Tarpon Springs, Florida. The circulating water system for the plant consists of six circulating water pumps, four cooling tower pumps serving two sidestream mechanical draft cooling towers, and four dilution pumps. The dilution pumps, which transfer water directly from the intake canal to the discharge canal, are capable of achieving FPC’s thermal discharge limitations when the ambient temperature is favorable. However, allowable dilution pump usage has been severely limited in past renewals of the NPDES Permit due to the conservative agency assumption that no zooplankton survived entrainment through these pumps. However, during a recent renewal of the NPDES Permit for Anclote, FPC proposed to the Florida Department of Environmental Protection (FDEP) an increase in dilution pump operation. To facilitate the review of this proposal, FPC agreed to perform a study of entrainment survival through the plant during September–November 1995. The results of this study demonstrated that overall entrainment survival for selected life stages and species of zooplankton, including ichthyoplankton, was significantly greater than had been previously hypothesized. Interestingly, the data demonstrated that zooplankton survived entrainment through the unit condensers at a mean overall rate of 68.2%, despite experiencing a temperature differential of up to 7°C. Mean overall survival through the dilution pumps was calculated to be 87.0%. This information was used by the FDEP as the basis for a permit revision allowing increased usage of the dilution pumps for control of thermal discharges. This allows FPC to greatly reduce operation of the cooling towers, which cause near total mortality of entrained zooplankton due to mechanical and chemical stressors.     

Entrainment and impingement studies at two power plants on the Wabash River in Indiana

Fish entrainment and impingement studies were conducted at Cayuga and Wabash River generating Stations in 1987 and 1988, respectively. Concurrent river samplings were conducted upstream from the stations to assess adult fish and ichthyoplankton populations. The original 316(b) studies at these stations were conducted in 1976–1977 and concluded that the stations were having minimal adverse impact on the Wabash River fish community. The state regulatory agency did not agree with this interpretation and requested the subsequent 1987 and 1988 studies. The major issue at these once-through cooling power plants was the large water withdrawals at Cayuga and Wabash River Stations [1318 and 1096 cubic feet per second (cfs) maximum plant flows, respectively], in contrast to the relatively low average annual Wabash River flows (10,070 and 11,110 cfs, respectively). The close proximity of the stations (35 river miles apart) together with the high percentage of water withdrawn suggest that the potential risk of unacceptable impacts is high.The six-month impingement estimates for Cayuga and Wabash River Stations were 15,086 and 11,401 fish, respectively. Impingement catches at both stations were dominated by young-of-the-year (YOY) channel catfish and gizzard shad. In addition, small minnows (primarily bullhead minnow and emerald shiners) were commonly impinged at Cayuga Station. Minnows (predominantly spotfin shiner, bullhead minnow and emerald shiner) were also the dominant species in the river samplings upstream from the stations. In the entrainment samplings, an estimated 26,920,382 and 107,503,876 fish eggs and larvae were entrained each year at Cayuga and Wabash River Stations, respectively. Ictiobinae (buffaloes and carpsuckers) and Cyprinidae (minnows and shiners) were the dominant ichthyoplankton in the river. Approximately 3.5 and 23% of the total river ichthyoplankton were entrained at Cayuga and Wabash River Stations, respectively. Gizzard shad at Cayuga Station, and Ictiobinae and Cyprinidae at Wabash River Station (WRS) were the dominant taxa entrained by the stations. Unusually low river flows during the spring and summer of 1987 and 1988 provided worst-case conditions for entrainment and impingement at the stations. However, the relatively low impingement and entrainment numbers during these worst-case conditions indicated that these stations were not adversely affecting the Wabash River fish community.     

Fish protection technologies: a status report

Section 316(b) of the Clean Water Act has required that “best technology available” (BTA) be used to minimize adverse environmental impacts resulting from operation of the cooling water intake structure (CWIS). The primary effects of CWIS operations are the entrainment of small aquatic organisms through the cooling water system and the impingement of larger life stages on traveling water screens. Extensive research has been conducted since the early 1970s in attempts to develop technologies that will minimize entrainment and impingement. As a result, a suite of technologies is available that can be considered for application as the BTA at the CWIS. Available technologies include fish collection systems, fish diversion systems, physical barriers and behavioral barriers. The ability of a given technology to meet BTA requirements is influenced by a wide variety of biological, environmental and engineering factors that must be evaluated on a site-specific basis. The status of systems and devices in each category of fish protection alternatives is presented.     

Intake modifications to reduce entrainment and impingement at Carolina Power & Light Company’s Brunswick Steam Electric Plant,Southport, North Carolina

The Brunswick Steam Electric Plant (BSEP) is a two-unit nuclear station located in the lower Cape Fear River Estuary (CFE) near Southport, NC. Once-through cooling water is withdrawn from the CFE and discharged to the Atlantic Ocean. Estuarine-dependent fish and shellfish species are potentially subject to entrainment and impingement during cooling-water withdrawal. Mitigation technologies include a fish diversion structure (9.4-mm mesh screens) at the mouth of the intake canal to reduce impingement of large organisms, 1-mm fine-mesh traveling screens to reduce entrainment of larvae, a fish return system to return impinged organisms alive back to the estuary, and flow minimization. Installation of the fish diversion structure resulted in a 40% reduction in number and 70% reduction in the weight of larger organisms impinged. Use of fine-mesh screens successfully reduced the number of organisms entrained by as much as 80% depending upon species present. Survival of organisms returned to the CFE ranged from <1% to approximately 92% depending upon species and size class. In addition to monitoring the effectiveness of the intake modifications, over 20 years of extensive environmental studies in the estuary indicate that operation of the BSEP has had no measurable adverse effect on the fisheries of the CFE. The species composition, seasonality, and abundance of organisms using the CFE have not changed as a result of operation of the BSEP.     

Evaluation of the effectiveness of intake wedgewire screens

The Logan Generating Plant (LGP), owned and operated by US Generating Company, is located on the shore of the Delaware River in New Jersey. It withdraws make-up water from the river to replace evaporative water losses from its closed-cycle cooling tower system. The intake is equipped with two intake conduits that are situated perpendicularly to the current and terminate on the river bottom at depth of approximately 3 m. The intake terminuses are covered by cylinders constructed of 1-mm wedgewire screen.The LGPs intakes are located in an area of the river where striped bass spawn and rear. Previous studies determined that without screening, the plant would withdraw less than 0.03% of the study area’s striped bass. LGP was required to conduct an intake screen performance test to document the plant’s entrainment of striped bass eggs and larvae.Entrainment samples were collected from water filtered through the wedgewire screens. Source water body samples were collected from three transects in the river: one upriver, one down river, and one directly in front of the plant. Sampling at the transect in front of the intake was coordinated to occur at the same time as entrainment sampling.The densities of striped bass larvae in the source water body and in entrainment samples were used to estimate proportional withdrawal. The study found that the wedgewire screens performed better than expected. The average proportional withdrawal of striped bass larvae was 0.003%, an order of magnitude less than the estimate for an unscreened intake.     

Wisconsin Electric’s experience with fish impingement and entrainment studies

Since 1975, Wisconsin Electric has conducted impingement studies at seven steam electric, once-through cooling-equipped power plants, as well as at one closed-cycle cooling system-equipped plant. Entrainment studies were also conducted at all seven once-through cooling-equipped plants. All eight plants are located on the Great Lakes or on major tributaries to them. Two of the eight plants have since been retired, while portions of two remaining multi-unit plants have been retired.As part of the study reports ultimately filed with the state agencies overseeing the studies, companies were also required to provide information on: intake design, capacity, and operation; whether biocides were used at the plants to control biofouling; and what ice control measures were employed during the winter season. Companies were also asked to provide brief assessments of available intake design alternatives that could be reasonably expected to reduce entrainment or impingement, as well as order of magnitude cost estimates for retrofiting plants with feasible alternative technologies.The studies concluded that since the vast majority of fish impinged during the 1975–1976 period were alewife and rainbow smelt (the then most abundant species in Lakes Michigan and Superior) and since the historic commercial harvests of these two species greatly exceeded annual impingement estimates, the impact of these incremental losses to lake-wide populations was inconsequential. With respect to the entrainment results, the studies detected few fish eggs or larvae that were not alewife or smelt.As a consequence of these findings, the company did not believe that any structural modifications to the intakes were necessary, since any one of the feasible alternatives would have been very costly. The state agencies concurred with these findings.     

太湖上游水环境对植物分布格局的影响机制

对北太湖上游流域的苏南第二大湖泊滆湖及其入太湖的主要河流(太滆运河与漕桥河)的水质和水生植被开展调查、评价与环境生态学研究。调查结果表明所有样点水质均超富营养化,尤以太滆运河与漕桥河的水体污染为甚。通过PCA综合评价,河流绝大多数河段已是Ⅳ类水体,滆湖也已呈Ⅲ类水体。对水生植物类群调查而言,调查发现太隔运河和漕桥河中上游河段水生植物多样性指数均很小,凤眼莲、芦苇和菰为优势种,沉水植被分布很少,群落退化严重,耐污种篦齿眼子菜和水盾草占优势;在湖泊中心区,沉水植物已完全退化。聚类分析发现所调查的植物可分为3大类群。PCO和CCA分别表明河流与湖泊所在的样点间的水体理化性状出现很明显的分离;该流域水体中不同形态N、P含量或底泥N、P含量主要影响水生植物种类组成和分布。     

辽东湾东部海域核电冷源取水区的风险生物分析

我国近年来在核电冷源取水系统运行过程中,因海洋生物聚集或暴发等原因,屡次堵塞冷源取水系统,造成取水水泵、发电机组甚至反应堆异常停止,给核电正常运行带来了较大风险。建立核电冷源取水区的风险生物目录,并有针对性地研究其监测、预警技术和防控对策,是核电冷源取水系统安全运行的前提。通过2015年6~11月在红沿河核电取水区及其临近海域的调查,筛选出对冷源取水系统风险值为"高"的海洋生物主要有长石莼（缘管浒苔）（Ulva linza）、孔石莼（Ulva pertusa）、海月水母（Aurelia aurita）、沙蛰（Nemopilema nomurai）、球型侧腕水母（Pleurobrachia globosa）、中国毛虾（Acetes chinensis）等。其中海月水母的风险分级基准为:大于或等于500 ind./（net.h）时风险为"高",为红色预警级别;大于300而小于500 ind./（net.h）时风险为"中",为黄色预警级别;大于100而小于300 ind./（net.h）时风险为"低",为蓝色预警级别。     

Cooling water use patterns at US nonutility electric generating facilities

Cooling water is used by many industrial facilities. The largest user of cooling water is the electric power industry, although other significant users include the pulp and paper, chemical, iron and steel, aluminum, and petroleum refining industries. The US Environmental Protection Agency (EPA) is currently developing regulations to implement section 316(b) of the Clean Water Act, which deals with cooling water intake structures. The EPA will examine cooling water use patterns at various industries. Data pertaining to cooling water use patterns at utility plants are readily available; however, no information has been assembled for cooling water use at electric power generating facilities owned or operated by entities other than utilities (nonutilities). This paper presents data concerning cooling water use from two subsets of the nonutility sector and focuses on plants using once-through cooling systems. The first subset includes 123 nonutility plants that each generate at least 150 MW of power. Collectively, they represent 41,494 MW of generating capacity, or about 56% of the total nonutility generating capacity. Approximately 17% of the installations within that subset utilize once-through cooling water. The second subset includes 58 waste-to-energy facilities, which individually produce less than 80 MW but collectively generate about 2200 MW. Only 11% of this subset of plants uses once-through cooling water. The total 15,372 MW generated by once-through nonutilities is equivalent to only 6% of the 258,906 MW generated by utilities utilizing once-through cooling. From a national perspective this share may appear relatively insignificant. However, in some states, the nonutility once-through total is equivalent to a more significant percentage of the utility once-through total.     

火电厂空冷机组水耗及煤耗性能分析

采用空冷机组是解决富煤贫水地区发电的有效措施,在中国西北部运用有着极为实际的意义,因此对中国燃煤电厂空冷机组的节水性能进行定量分析也具有现实意义。文章从国内外火电厂直接空冷机组与间接空冷机组发展的历史过程出发,在对近100个不同等级、不同冷却方式的火电项目样本进行统计分析的基础上,分别对直接空冷、间接空冷机组与常规火电机组的水耗及煤耗性能进行定量分析与比较,得出相应的水耗及煤耗结果,给出了水耗与煤耗的相关性,并给出相应的火电厂节水建议。     

基于核电冷源安全的海洋生物调查及筛选评价方法研究

我国滨海核电项目已发生多起海洋生物暴发导致取水系统异常的事件。当前核电厂建设前期海洋生物调查与评价缺乏对致灾海洋生物的针对性。本文结合国内外已开展的致灾海洋生物与核电厂冷源安全的现场工作反馈,分析了现有核电项目建设前期海洋生物调查工作的不足,提出了调查方案的优化措施,以尝试增强海洋生物调查、筛选评价与核电厂冷源安全纵深防御体系的关联。     

Estimating the abundance and egg production of spawning winter flounder (Pseudopleuronectes americanus) in the Niantic River,CT for use in the assessment of impact at Millstone Nuclear Power Station

The winter flounder is a coastal flatfish with spawning populations associated with specific estuaries or coastal areas. Because of its stock structure, this species is susceptible to localized impacts, including power plant entrainment of larvae. Winter flounder rank second in fish larvae entrained at the Millstone Nuclear Power Station (MNPS), located on Long Island Sound in Waterford, CT, USA. Because of its importance to the state’s fisheries, the population spawning in the nearby Niantic River was selected for impact assessment studies in the early 1970s. Northeast Utilities has consistently monitored annual abundance of adult spawners, characterizing relative abundance by trawl catch-per-unit-effort (CPUE) and absolute abundance using mark and recapture data with the Jolly model for demographically open populations. Trends in these two independent but highly correlated indices provide short-term assessments of winter flounder abundance. Abundance of winter flounder peaked in the early 1980s, but as fishing mortality increased to high levels in the late 1980s, their numbers declined thereafter and presently are very low. Information on sex ratio, length-frequency distribution, and spawning condition allow for calculation of annual egg production using a length-fecundity relationship. This forms the basis for estimating production loss due to larval entrainment, which is used as input to a long-term assessment model of power plant impact, discussed in an accompanying paper (Lorda et al., 2000: Lorda, E., Danila, D.J., Miller, J.D., 2000. Application of a population dynamics model to the probabilistic assessment of CWIS effects of Millstone Nuclear Power Station (Waterford, CT) on a nearby winter flounder spawning stock. Environmental Science & Policy 3, S471–S481).     

常州市水环境中精神活性物质污染特征与生态风险

为评估精神活性物质(psychoactive substances,PSs)在常州市水环境中的污染特征、潜在来源及生态风险,利用超高效液相色谱-质谱联用(UPLC-MS/MS)方法,检测了地表水(湖泊、河流及饮用水源水)中13种典型PSs的污染水平和分布特征. 结果表明:常州市湖泊、河流及饮用水源水三类地表水中甲基苯丙胺(methamphetamine,METH)、苯丙胺(amphetamine,AMP)、3,4-亚甲基二氧基苯丙胺(3,4-methylenedioxy amphetamine,MDA)、海洛因(heroin,HR)、氯胺酮(ketamine,KET)、美沙酮(methadone,MET)及麻黄碱(ephedrine,EPH)均有不同程度检出. ∑PSs (13种典型PSs)的检出浓度范围为0.67~39.03 ng/L,其中在河流中的检出频率和浓度较高,EPH (0.23~21.98 ng/L)和METH (nd~8.47 ng/L)是检出浓度和频率较高的单体目标物. 采用主成分分析对PSs的来源进行解析,发现医院、生活污水的直接排放以及污水处理厂出水可能是常州水体中PSs的主要来源. 对常州市水环境中PSs进行生态风险评估,发现新浮山水库及长荡湖中MET对水生生物具有低风险〔0.01相似文献   

Phase relations between a circadian rhythm and its zeitgeber within the range of entrainment

The regular day-night changes in tissues, physiologic functions, and behavior of organisms are based on endogenous rhythmic processes which under constant conditions continue with periods slightly deviating from 24h. These ‘arcadian’ rhythms have properties of self-sustained oscillators. Under natural conditions, circadian rhythms are synchronized (entrained) to 24 h by periodic factors in the environment, the so-called ‘Zeitgebers’. In the laboratory, circadian rhythms can also be entrained to periods other than 24 h within certain limits. Data on the phase relationship between the circadian rhythm and an entraining light-dark cycle for vertebrates, insects, plants, and unicellular organisms are reviewed.     

点篮子鱼(Siganus guttatus)对辽东湾核电厂冷源取水海域海藻生态防治的初步探讨

核电厂冷源取水海域海洋生物的异常暴发,会导致取水口堵塞,严重影响核电厂的正常运行。本文以点篮子鱼（Siganus guttatus）为实验对象,分别进行了室内和野外实验,室内模拟实验探讨了在不同温度（29℃、26℃、23℃、20℃和17℃）条件下点篮子鱼对常见优势藻类长石莼（缘管浒苔）（Ulva linza）的摄食作用,野外原位实验研究了点篮子鱼对长石莼和孔石莼（Ulva pertusa）的摄食行为。通过室内实验可以发现,点篮子鱼对长石莼有较强的摄食能力,并且在适合的生存温度范围内,温度越高摄食率越高,在29℃温度组中,平均摄食率高达7.86%;通过野外实验发现,点篮子鱼在实验海域生长良好,对长石莼和孔石莼喜好程度高且摄食积极。综上所述,点篮子鱼对辽东湾核电厂冷源取水海域具有海藻生态防治的潜力,但具体的实施措施和生态风险评估需要进一步探讨。本研究为核电厂冷源取水海域的海藻生态防治工作提供了理论基础和技术支持。     

Impacts of power-plant cooling systems on estuarine fish populations: the Hudson River after 25 years

In the early 1970s, impacts of power-plant cooling systems on fish populations were a major source of controversy. The most thoroughly studied and controversial power plants were the Indian Point, Bowline, and Roseton generating stations on the Hudson River. The assessments performed for these three plants were unique in employing river-wide sampling data and mathematical models designed to predict the effects of cooling-water withdrawals on the short- and long-term abundance of striped bass and other important fish populations. A Settlement Agreement in 1981 led to the establishment of a long-term monitoring program that continues to generate valuable information concerning the impacts of power-plant cooling systems on estuarine ecosystems. This paper evaluates the results generated by the past quarter century of Hudson River, with the objective of evaluating the utility of the information for future 316(b) assessments. Specific recommendations are made concerning: (1) methods for quantitative assessment of cooling-system impacts at new vs operating facilities; (2) research that would improve the efficiency and accuracy of assessments; and (3) the need to integrate cooling system impact studies into a general framework for management of aquatic ecosystems.     

What is ‘normative’ at cooling water intakes? Defining normalcy before judging adverse

Judgments of adverse environmental impact from cooling water intake structures need to be preceded by an appreciation of what is normal. In its report, Return to the River, the Independent Scientific Group (now called the Independent Scientific Advisory Board) — the scientific peer review arm of the Northwest Power Planning Council — advanced the notion of a ‘normative river ecosystem’ as a new conceptual foundation for salmonid recovery in the Columbia River basin. With this perspective, the sum of the best scientific understanding of how organisms and aquatic ecosystems function should be the norm or standard of measure for how we judge the effects of human activities on aquatic systems. For the best likelihood of recovery, key aspects of altered systems should be brought back toward normative (although not necessarily fully back to the historical or pristine state); new alterations should be judged for adversity by how much they move key attributes away from normative or what might be considered normal. In this paper, I ask what ‘normative’ is for the setting of cooling water intake structures and how this concept could help resolve long-standing disputes between groups interested in avoiding damage to all organisms that might be entrained or impinged and those who take a more population or community perspective for judging adverse environmental impact. In essence, I suggest that if a water intake does not move the aquatic ecosystem outside the ‘normative’ range, based on expressions of normalcy such as those discussed, then no adverse impact has occurred. Having an explicit baseline in normal or normative would place 316(b) analyses on the same conceptual foundation as 316(a) analyses, which strive to demonstrate the continuation of a balanced, indigenous community of aquatic organisms at the power station location.     

Blue water scarcity in the Black Sea catchment: Identifying key actors in the water-ecosystem-energy-food nexus

Large-scale water scarcity indicators have been widely used to map and inform decision makers and the public about the use of river flows, a vital and limited renewable resource. However, spatiotemporal interrelations among users and administrative entities are still lacking in most large-scale studies. Water scarcity and interrelations are at the core of the water-ecosystem-energy-food nexus. In this paper, we balance water availability in the Black Sea catchment with requirements and consumptive use of key water users, i.e., municipalities, power plants, manufacturing, irrigation and livestock breeding, accounting for evaporation from major reservoirs as well as environmental flow requirements. We use graph theory to highlight interrelations between users and countries along the hydrological network. The results show that water scarcity occurs mainly in the summer due to higher demand for irrigation and reservoir evaporation in conjunction with relatively lower water resources, and in the fall-winter period due to lower water resources and the relatively high demand for preserving ecosystems and from sectors other than irrigation. Cooling power plants and the demands of urban areas cause scarcity in many isolated locations in the winter and, to a far greater spatial extent, in the summer with the demands for irrigation. Interrelations in water scarcity-prone areas are mainly between relatively small, intra-national rivers, for which the underlying national and regional governments act as key players in mitigating water scarcity within the catchment. However, many interrelations exist for larger rivers, highlighting the need for international cooperation that could be achieved through a water-ecosystem-energy-food nexus.