Evaluation of energy expenditure in adult spring Chinook salmon migrating upstream in the Columbia River Basin: an assessment based on sequential proximate analysis

The upstream migration of adult anadromous salmonids in the Columbia River Basin (CRB) has been dramatically altered and fish may be experiencing energetically costly delays at dams. To explore this notion, we estimated the energetic costs of migration and reproduction of Yakima River‐bound spring Chinook salmon Oncorhynchus tshawytscha using a sequential analysis of their proximate composition (i.e., percent water, fat, protein, and ash). Tissues (muscle, viscera, and gonad) were sampled from fish near the start of their migration (Bonneville Dam), at a mid point (Roza Dam, 510 km upstream from Bonneville Dam) and from fresh carcasses on the spawning grounds (about 100 km above Roza Dam). At Bonneville Dam, the energy reserves of these fish were remarkably high, primarily due to the high percentage of fat in the muscle (18–20%; energy content over 11 kJ g^?1). The median travel time for fish from Bonneville to Roza Dam was 27 d and ranged from 18 to 42 d. Fish lost from 6 to 17% of their energy density in muscle, depending on travel time. On average, fish taking a relatively long time for migration between dams used from 5 to 8% more energy from the muscle than faster fish. From the time they passed Bonneville Dam to death, these fish, depending on gender, used 95–99% of their muscle and 73–86% of their visceral lipid stores. Also, both sexes used about 32% of their muscular and very little of their visceral protein stores. However, we were unable to relate energy use and reproductive success to migration history. Our results suggest a possible influence of the CRB hydroelectric system on adult salmonid energetics. Published in 2006 by John Wiley & Sons, Ltd.     

Seasonal Effects of Hydropeaking on Growth,Energetics and Movement of Juvenile Atlantic Salmon (Salmo Salar)

The performance and movements of juvenile Atlantic salmon Salmo salar exposed to variable water discharge (simulating hydropeaking) but with a stable water‐covered area were studied in six experimental stream channels, both during the winter and summer. Thirty fish were stocked into each channel, and the growth, body fat and movements of the fish were followed for about 2.5 months in each season. During the winter, no effect of hydropeaking was documented on performance or movement. In the summer, fish experiencing hydropeaking had lower body mass, lower body fat, and higher movement rates than the control fish. In general, effect sizes were small, and the rapid and frequent changes in water discharge and water level in the present study had small effects on the performance of juvenile Atlantic salmon. The cumulative long‐term effect at the population level is unknown, but a reduced growth rate of 10% and a reduction in body fat of 16% in the hydropeaking experiments in the summer might to some extent translate into increased smolt age and lower overwintering survival. Copyright © 2014 John Wiley & Sons, Ltd.     

Atlantic salmon (Salmo salar) in the regulated River Alta: effects of altered water temperature on parr growth

The chief objective of this study was to analyse the effects of altered water temperature, due to the hydropower regulation of the River Alta, on growth of Atlantic salmon parr. The river was developed for hydroelectric purposes in 1987. A 110 m high concrete dam was built in the main river 49 km upstream from the outlet to the sea. The outlet of the power station is located 2.5 km downstream from the dam. The annual regime of water temperature has been altered downstream from the power station because of the regulation. It has decreased 1–2° C during June, July and the first half of August, while it has increased up to 3° C during late summer. During winter, water temperature has increased from 0° C to about 0.3–0.4° C. Atlantic salmon is the predominant fish species in the river. They can penetrate 46 km from the sea, up to the outlet of the power station. In this paper I have studied the relationship between growth of juvenile Atlantic salmon and water temperature in the upper part of the river. At similar temperatures, the growth rate of salmon parr in the River Alta is higher in early summer than later in the growing season. In early summer the salmon grew faster than the maximum rate predicted by a recently published model. Therefore, I adjusted the model to describe growth rates of salmon in early summer (ice break to mid‐August), using data derived prior to the hydropower development (1981–1986). The new model proved effective at describing growth rates of fish in early summer following the hydropower development (1987–1996). After development, growth rates decreased during early summer, but increased correspondingly later in the season. There was close agreement between these growth changes and the altered annual regime of river temperature. Overall, only minor changes in annual growth rates have been observed after the hydropower development. Copyright © 2003 John Wiley & Sons, Ltd.     

Contrasting temperatures,waterflows, and light: seasonal habitat selection by young Atlantic salmon and brown trout in a boreonemoral river

Habitat use and habitat selection by young Atlantic salmon and brown trout were investigated by direct underwater observation. We sampled during winter and summer water temperatures (low: 3–7°C; high: 9–12°C) coinciding with low and high waterflows (12–20 and 60–80 m³ s^?1), and during day and night in winter, and on six selected stations in the river. Observations of 396 salmon and 120 trout indicated a distinct seasonal pattern in behaviours and habitat selection. Feeding was the dominant behaviour at high water temperatures during summer. In winter, there was a diurnal pattern in behaviour; both species sheltered in interstitial spaces in the substrate during daylight, but during night held positions on or close to the substrate in slower flowing stream areas. Coarse substrate providing cover was therefore an important habitat factor during daylight at low water temperatures, while slow‐flowing water was important during night. Although spatial niche overlap was considerable both in summer and winter, salmon and trout segregated with respect to meso‐ and microhabitat selection, and relatively more at low temperatures. Both species changed their use of mesohabitats towards more slow‐flowing glide/flat habitats in winter. Irrespective of season, trout preferred in general more slow‐flowing water than salmon did, but the difference was more pronounced in winter. Salmon used a wider range of water depths and in particular water velocities, than did trout. Both species were less tolerant of high water velocities at low water temperatures. The seasonal and diurnal pattern in habitat selection reported have important implications for habitat research and habitat‐hydraulic modelling. Copyright © 2001 John Wiley & Sons, Ltd.     

Differential lipid dynamics in stocked and wild juvenile lake trout

After 45 years of stocking, lake trout in Lake Champlain have started to exhibit strong natural recruitment, suggesting a recent change in limiting factors such as prey availability or overwinter survival. The abundance of juvenile wild lake trout varies among regions of Lake Champlain which suggests the prey base, or foraging success, may vary geographically within the lake. One metric that can indicate differences in resources across regions is lake trout lipid content, which reflects the availability of food and serves as an important energy reserve for overwinter survival. We quantified total lipid content of stocked and wild age-0 to age-3 lake trout among lake regions and seasons. No spatial differences in lipid content were apparent, but wild fish had higher overall mean ± SE percent total lipid content (17.0 ± 0.7% of dry mass) than stocked fish (15.2 ± 0.7%). Lipids in fish stocked in November were high (35.1 ± 0.7% of dry mass) but dropped by spring (14.9 ± 1.3%) and continued to decline through autumn. Wild fish showed seasonal changes with winter depletion in lipids followed by summer increase, and a plateau in autumn. The lipid depletion in stocked fish poses two competing hypotheses: 1) the high lipid concentration is necessary for stocked age-0 fish to transition to foraging in the wild, or 2) the high lipid concentration is difficult to maintain on a wild diet and reduces survival in the first post-stocking year.     

Dam and geomorphological influences on colorado river waterbird distribution,Grand Canyon,Arizona, USA

Impoundment effects override natural, reach-based channel geomorphology influences on seasonal waterbird distribution in Grand Canyon along the Colorado River downstream from Glen Canyon Dam. Large winter waterbird populations were rare or non-existent prior to completion of Glen Canyon Dam in 1963, and pre-dam summer breeding was rare. Post-dam river corridor surveys of 13 geomorphological reaches from 1973 to 1994 detected 58 species of waterfowl, waders, shorebirds and piscivorous raptors, with a grand mean of 138·2 waterbirds/reach (SE=31·0, n=727 reach surveys), and a mean area-adjusted rate of encounter (AARE) of 372·8 waterbirds km⁻¹ h⁻¹ of observation per reach (SE=69·1). The post-dam assemblage has been dominated by Anseriformes (13 diving and 12 dabbling species) and includes regionally significant populations of wintering waterfowl and bald eagle, and breeding mallard. Most wading birds and shorebirds occur primarily as migrants or summer vagrants. Total waterbird AARE was greatest in the productive clear water (CW) and variably turbid (VT) segments upstream from the Little Colorado River (LCR) (km 98), decreasing downstream on the usually turbid (UT) lower Grand Canyon segment. Mean total winter waterfowl AARE was 1076·8, and decreased by three orders of magnitude from the CW to the UT segments (p=0·0001). Mean total summer AARE was 2·7, and also decreased across the turbidity segments (p=0·066). In contrast, AARE varied little between wide and narrow geomorphological reaches. Total AARE was only 1·4 and 1·3-fold greater in wide versus narrow reaches within the VT and UT turbidity segments, respectively (p<0·0002). Winter AARE was threefold greater (p=0·0002), while summer AARE was equivalent between wide and narrow reaches. These tributary-related turbidity and geomorphological reach width factors contributed to a non-linear, circuitous shift in the waterbird assemblage over distance downstream from the dam, differentially affecting the seasonal distribution of waterbird feeding guilds. We discuss flow regulation and habitat management implications. © 1997 John Wiley & Sons, Ltd.     

Habitat utilization and preferences in juvenile atlantic salmon (salmo salar) in streams

Young Atlantic salmon appear to occupy similar suitable stream habitats year round. The salmon is stationary, often associated with “home stones”. At low water temperatures in winter, the fish seek shelter in the substrate, which has to be coarse enough to provide interstices for the fish to hide in. In summer, salmon select habitats within tolerable ranges of habitat variables, rather than narrow optima. It is suggested that a genetic basis to habitat evaluation allows incorporation of the full range of behavioural responses. This is important as partially different habitats may be selected in diverse streams. Habitat availability influences both habitat use and habitat preferences. Suitable summer habitats have depths in the range 5–90 cm; mean water velocities 10–80 cm s^?1, and gravel-to-boulder substratum. Fish size affects habitat use, as young of the year are found in the more shallow habitats closer to the stream banks, whereas the older parr use a wider range of habitats. In the absence of brown trout, the Atlantic salmon parr, and especially young of the year, use habitats otherwise inhabited by brown trout. Water velocities are in many cases the principal physical habitat variable determining the distribution of Atlantic salmon in streams, but other variables are also important. Depth is more important in small streams than in large streams.     

Optimal sampling designs for estimating salmonid run abundances from video recordings at a fishway on the Bois Brule River,Wisconsin, a tributary to Lake Superior

Using a simulation program and video census data (2004–2018) from the Bois Brule River fishway, Wisconsin, USA, we compared alternative sampling designs to estimate spawning run abundances of steelhead, coho salmon, Chinook salmon, and brown trout. We evaluated two types of two-stage sampling designs, comprising varying numbers of days sampled within a year (1st stage samples) and varying numbers of hours sampled within a day (2nd stage samples). While days were sampled using stratified random sampling under both types of sampling designs, hours were sampled using uniform (1/24) or non-uniform (proportional to hourly runs) selection probabilities under the first and second types of sampling designs, respectively. Number of days sampled within a year, comprising three strata, varied from 30 to 200 days in 10-day increments, and number of hours sampled within a day varied from 2 to 24 h in 2-hour increments. Spawning run sizes of the salmonids could be estimated with a relative root mean square error (RMSE) of less than 10% on average by employing a two-stage sampling design with samples of 100 days·yr⁻¹ and 8 hrs·day⁻¹, i.e., 800 hrs·yr⁻¹; by contrast, full census involved reviewing 250 days·yr⁻¹ and 24 hrs·day⁻¹, i.e., 6000 hrs·yr⁻¹, of video. Sampling more days (>100) resulted in greater reductions in estimation error than sampling more hours (>8). Non-uniform (vs. uniform) selection probabilities for hours sampled slightly reduced error of estimates. Our results underscore that optimal sampling designs could ensure a considerable reduction in survey resources while maintaining relatively low error in estimation of salmonid abundances.     

Juvenile masu salmon in a regulated river

We examined the relationship between the physical environment and habitat use of juvenile masu salmon, Oncorhynchus masou, in the Nobori River in Hokkaido, Japan to provide a perspective for the conservation of fish habitat in regulated streams. The study was undertaken during the autumn and winter, with an emphasis on the hierarchy of three spatial scales: microhabitat, channel‐unit and reach scales. The microhabitat‐scale analysis indicated juvenile masu salmon preferred a midstream habitat type, with a greater depth (Avg. ± SD: 35.4 ± 14.2 cm) and high (43.4 ± 23.1 cm s^?1) and uniform current velocities during the autumn, and a channel margin habitat type with a moderate current (about 20 cm s^?1) and submerged cover during winter. In addition, different cover types have different roles in determining juvenile salmon distributions during winter. Grass cover had extremely high carrying capacities, whereas coarse substrate cover provided winter habitat for larger juvenile salmon. Channel‐unit scale analyses showed that abundance of juvenile salmon tended to be higher in pools than runs in the autumn through winter. Reach‐scale analysis showed that abundance and mean body length of juvenile salmon significantly differed between differently regulated reaches during winter, associated with the dominant cover type in each reach. This study demonstrated that the habitat conditions determining juvenile masu salmon distribution differ according to the season and scale of analysis. Therefore, for conservation of fish communities, it is important to evaluate and conserve or create fish habitats in regulated reaches, with a focus on the hierarchy of spatial scales and seasonal differences. Copyright © 2007 John Wiley & Sons, Ltd.     

HIGH‐HEAD DAMS AFFECT DOWNSTREAM FISH PASSAGE TIMING AND SURVIVAL IN THE MIDDLE FORK WILLAMETTE RIVER

Many high‐head dams in Oregon's Willamette River basin were constructed without fish passage facilities for downstream migrants. Instead, fish pass dams via hydroelectric turbines, surface spillways or deep‐water regulating outlets. The availability of these routes varies seasonally with dam operations and reservoir depth, which can fluctuate by tens of meters. To assess how dam and reservoir operations affect fish movement timing and survival, we used rotary screw traps below three Willamette basin dams and at two riverine sites above reservoirs. Traps were operated 2950 days over 8 years, and >195 000 fish were collected. Samples above reservoirs were primarily native salmonids (Oncorhynchus spp.), daces (Rhinichthys spp.) and sculpins (Cottus spp.), while those below dams were often dominated by non‐native Centrarchidae. Capture rates at riverine sites were highest from late winter to early summer, coincident with juvenile Chinook salmon emigration. Conversely, collection below dams was largely restricted to late fall and winter when reservoirs were drawn down to annual lows and discharge was high. We hypothesize that winter operations facilitated fish access to dam turbines and regulating outlets, whereas spring–summer operations entrapped fish in reservoirs and restricted volitional downstream passage. Total fish mortality was ≤2% at riverine sites and was 36–69% below dams. Estimates were highest for non‐native species and juvenile Chinook salmon. Fatal injuries were consistent with traumas related to pressure, shear and contact and there were size‐related and morphology‐related risk differences. Mitigation opportunities include fish bypass system development, retrofits for existing routes and seasonally appropriate reservoir draw down to allow fish passage. Copyright © 2012 John Wiley & Sons, Ltd.     

Temperature-dependent Effects of Rainbow Trout on Growth of Atlantic Salmon Parr

Temperature may influence interactions between species by regulating energy balances of individuals. We conducted a laboratory study to determine whether temperature influenced the effects exerted by large rainbow trout on the growth of Atlantic salmon parr. Bioenergetic models were used to predict maintenance rations so that food resources were limiting over a range of temperatures; equal biomasses of rainbow trout were substituted for Atlantic salmon to evaluate the relative effect of interspecific interactions on Atlantic salmon growth. In the presence of rainbow trout, salmon growth increased as temperatures increased from 15°C to 25°C; no such temperature effect occurred for salmon maintained alone. Growth differences between salmon maintained with and without trout were highly significant at 25°C but not at 15°C. We conclude that the presence of trout depressed salmon growth at 15°C but not at higher temperatures, most likely a result of differences in thermal optima between these two species. Field data show that the proportion of stocked Atlantic salmon to wild rainbow trout coexisting in natural streams is a function of mean summer temperature. As stream temperatures increased, Atlantic salmon became increasingly favored over rainbow trout, but with a concomitant decrease in total salmonine biomass. We suggest that Atlantic salmon restoration programs focus more attention on relatively warm streams in watersheds where interactions with naturalized rainbow trout may occur.     

Effect of stream regulation on population parameters of atlantic salmon [Salmo salar L.] in the river Lærdalselva,western Norway

The river Lærdalselva, West Norway, was regulated in the autumn of 1974. Regulation led to an increase in winter flow and a decrease in summer flow in a section where there was natural production of salmon. A slight decrease in summer temperature was also recorded in the uppermost part of this section. No data existed on juvenile Atlantic salmon before regulation and the regulation effect on juvenile fish population parameters is therefore based on samples taken from adult salmon in the period 1969 to 1984. No differences in growth, smolt age, and smolt size which could be related to the regulation of the river were found. The smallest mean sizes of yearlings (0+) were found in 1964 and 1967. After regulation the mean size was never lower than before. Mean smolt age was between 3–1 and 3–9 years, but after regulation never exceeded that found before. River growth was slow, three year old smolts growing faster than four year old smolts. However, there were no differences in river growth before and after regulation.     

Energy content of young yellow perch and walleye in Saginaw Bay

We evaluated seasonal energy content of age-0 yellow perch Perca flavescens and walleye Sander vitreus in Saginaw Bay, Lake Huron in 2009 and 2010. We also determined the energy content of age-1 fish from the 2009 and 2010 cohorts the following spring (i.e., for fish that had survived one winter) to evaluate overwinter energy losses. As expected, larger fish within each species had disproportionately higher energy content (i.e., slope relating length and energy > 3.0) than smaller conspecifics. By contrast to expectations, allometric slopes were > 3.0 in nearly all months, not just the fall, and were higher for age-0 yellow perch than for walleye, even though increased allocation to growth would have seemingly been beneficial to even the largest yellow perch during summer. Seasonal energy allocation patterns differed between years. In 2009, length specific energy content increased from late summer to fall for both species. However, for the 2010 cohorts of fish, length specific energy content decreased between late summer and fall for yellow perch and did not change for walleye. There were 13–17% overwinter declines in length specific energy content between the fall (October or November) and the spring (May) with no major differences between cohorts within a species or between species for a given year. Because young yellow perch and walleye are similar physiologically but differ in size (i.e., yellow perch are smaller), it is possible that overwinter energy losses are more important for yellow perch than for walleye.     

Modelling the Effects of Climate Change on Water Resources in Central Sweden

This article describes investigationsinto the effects of climate change on flow regimes oftwenty-five catchments (from 6 to 1293 km²) incentral Sweden. Hydrological responses of fifteenhypothetical climate change scenarios (e.g.combinations of T = +1, +2 and +4 °C andP = 0, ± 10%, ± 20%) were simulated by a conceptual monthly water balance model. The results suggest thatall the hypothetical climate change scenarios wouldcause major decreases in winter snow accumulation.Significant increase of winter flow and decrease ofspring and summer runoff were resulted from mostscenarios. Attendant changes in actualevapotranspiration were also examined for all climatechange scenarios. Despite the changes in seasonaldistribution of evapotranspiration, the change inannual total evapotranspiration was relatively smallwith the maximum change of 23% compared with the 76%for mean annual snow water equivalent changes and 52%for mean annual runoff changes. Such hydrologicresults would have significant implications on futurewater resources design and management.     

First assessment of methane and carbon dioxide emissions from shallow and deep zones of boreal reservoirs upon ice break-up

Most studies dealing with greenhouse gas (GHG) emissions from large boreal reservoirs were conducted during the ice‐free period. In this paper, the potential methane (CH₄) and carbon dioxide emissions are estimated for two hydroelectric reservoirs, as well as for a small experimental reservoir from boreal latitudes (northern Quebec, Canada) at the ice break‐up event through diffusion (diffusive fluxes) and release of bubbles (bubbling fluxes). The results of this preliminary study suggest that the winter diffusive fluxes at the air–water interface of the sampled reservoirs represent < 7% of their cumulative carbon emissions during the ice‐free period. Furthermore, the release upon ice‐break of CH₄ bubbles accumulated under the ice cover during the winter could represent  2% of the summer carbon emissions from hydroelectric reservoirs in northern Quebec. The results presented herein suggest that the GHG emissions upon ice break‐up from the boreal reservoirs investigated are a small, but non‐negligible, component of their annual GHG emissions.     

Multi‐objective analysis of boating and fishlife interests in Lake Sommen,Sweden

The conflicts between boating and fishlife interests in Lake Sommen and hydroelectric, irrigation and urban water supply uses in the Svartå river downstream of Lake Sommen are examined using a goal programming model. The desired water levels corresponding to boating and fishlife interests in Lake Sommen are specified as minimum goals. The hydroelectric, irrigation and water supply needs in the Svartå river are specified as minimum levels within the constraint set for the model. The model was applied for a range of levels of the hydroelectric, irrigation and urban water supply uses. During the winter periods the lake level goals for fishing and boating are always fulfilled. However, in the dry periods, in which fishing and boating interests are critical, the goals are not met during the summer. Furthermore there appears to be very little flexibility within the present operating system to improve boating and fishing conditions during these dry summer periods.     

岩滩水电站建设对水生生物的影响

根据岩滩水电站河段近30年水生生物自然资源长序列数据,分析水电站建设对水生生物自然资源的影响,研究红水河流域渔业自然资源枯竭的原因。结果表明:岩滩水电站蓄水11年,库区浮游植物种类减少2.7%,单位体积生物质量为蓄水前的4.4倍;浮游动物种类增加97.9%,单位体积生物质量为蓄水前的16.1倍;底栖动物种类减少70.6%,单位面积生物质量为蓄水前的5倍;水生维管束植物种类增加80%;鱼类种类减少40%。岩滩水电站建设前后水域生态环境发生重大变化,水生生物种类组成及生物量结构差异显著,鱼类及底栖动物种类的生物多样性损害严重。     

Remote Sensing and GIS Innovation with Hydrologic Modelling for Hydroelectric Power Plant (HPP) in Poorly Gauged Basins

Within the last two decades, modelling of rainfall–runoff has become an important topic in water resources assessment due to increasing water demand and energy, particularly in the determination of hydropower potential. In addition to remote sensing (RS) and geographical information systems (GIS), with the development on satellite technologies, it becomes possible to asses rapid and economic solutions to determine a practical rainfall–runoff relation, particularly poorly gauged or ungauged basins. In this paper, Solakli Watershed which is located in Eastern Black Sea Region of Turkey is selected as the study area. To determine the hydroelectric water potential in a poorly gauged basin, basin boundary and area, minimum maximum and mean elevation, slope information of the basin have been derived from the digital elevation model (DEM) using remote sensing (RS) and geographical information systems (GIS) techniques. IRS P5 stereo satellite data with 2.5-m spatial resolution has been used for deriving the DEM. This DEM is used to produce the flow direction and flow accumulation maps of the basin. Afterward, synthetic drainage network is obtained with the analysis of these maps. Using topographical data such as area, mean basin elevation and limited point observations of rainfall data; a regression model was derived for the whole watershed. This regression model was validated on a sub-basin with satisfactory results using mean areal rainfall which was calculated isohyetal map produced by kriging method. Suggested hydropower station points are also determined.     

Seasonal selection of habitat by Spotted Bass and Shorthead Redhorse in a regulated river in the Midwest,USA

Riverine fish populations depend on habitats supporting their resource and life history needs. Dynamic streamflow caused by river regulation or natural events influences the distribution of downstream habitat characteristics. Through studying habitat selection, we can identify the most utilized and valuable habitats for the success of native fishes. We determined seasonal habitat selection of two common, native fish species on the Osage River downstream of Bagnell Dam, a hydroelectric dam in central Missouri, from April 2016 to June 2017 using radio telemetry. Spotted Bass (Micropterus punctulatus) are nest‐guarders, sight feeders, and habitat generalists, whereas Shorthead Redhorse (Moxostoma macrolepidotum) are fluvial dependent, migratory, and benthic feeders. Bayesian discrete choice analyses determined that both species selected particular water depth, velocity, and presence of submerged cover in some or all seasons, even as available habitat changed. Spotted Bass selected water depths <4.0 m near submerged cover during all seasons, low velocity during spring and summer, and near‐bank habitat in all seasons except spring. Shorthead Redhorse used fast flowing habitat during spring, 0.4–1.1 m/s velocity during summer, and low velocity in fall and winter (0.1–0.5 m/s). Shorthead Redhorse used submerged cover in all seasons except summer and selected specific ranges of depth within spring (2.4–4.4 m), summer (3.3–6.7 m), and winter (1.1–2.3 m). Our findings suggest that maintaining habitats with cover and diverse water depths and velocities, particularly both low and high velocity habitats during spring, may promote resilience by providing beneficial habitats for native fishes.     

珠江磨刀门河口日均水位变化及影响因子辨识

珠江磨刀门河口日均水位变动的态势受自然过程与强人类活动的驱动,呈现出明显的阶段性演变与季节性异变。辨识日均水位的影响因子,是河口动力学研究的重要内容,对河口治理和水资源高效开发利用具有重要指导意义。本文通过流量驱动的数据驱动模型,对磨刀门河口沿程主要站点长时间日均水位序列(1959—2016年)进行分解,分解出由地形和海平面边界共同驱动以及仅由上游马口站流量边界驱动引起的日均水位变化。地形和海平面边界共同驱动的结果表明:甘竹-灯笼山河段春夏两季日均水位变化主要由河道挖沙引起,日均水位下降(平均下降0.26 m);秋冬两季则由口门围垦与海平面边界控制,日均水位抬升(平均抬升0.07 m)。仅由上游马口站流量边界驱动的结果表明:春夏秋三季日均水位变化主要由水库蓄水主导,日均水位下降(平均下降0.13 m);冬季日均水位变化受水库调枯影响,日均水位抬升(平均抬升0.03 m);从量值上看,地形和海平面边界对磨刀门河口日均水位变动的影响大于上游水库调蓄作用。