Shallow River Research Articles

Female-biased Sex Ratios and Control Effects Observed in Two Local Populations of Red-eared Slider Turtles (Trachemys scripta elegans) in Western Japan

High abundance of invasive red-eared slider (RES) turtles (Trachemys scripta elegans) in Japan has been a serious issue in freshwater ecosystems. Information on reproductive parameters, such as sex ratios, of RES turtles is needed to effectively control the invasive species. We conducted a long-term field study on RES turtles at two study sites: the Taisho River (a shallow river) and Teradaike Pond (an irrigation reservoir that was irregularly drained to maintain the embankment and water quality) in western Japan. Using trapping and muddling methods, we captured RES turtles and checked for sex, carapace length, and body weight. We also examined whether the population of RES turtles could be reduced by continuously removing the turtles captured at each study site. The sex ratio (male/both sexes) of RES turtles that could be sexed by external morphology (presumably adult turtles) was 0.27 at the Taisho River and 0.26 at Teradaike Pond. At both sites, these sex ratios were almost the same as those of RES turtles that could be sexed only by necropsy after euthanasia (presumably juvenile turtles). These sex ratios were markedly biased toward females and consistent between the adult and the juvenile turtles, thus suggesting that more females had been produced than males. At the Taisho River, a total of 1,366 RES turtles were captured and eliminated over more than ten years. Nevertheless, the annual catch did not tend to decrease and only an effect of preventing population growth was observed. At Teradaike Pond, a total of 1,831 RES turtles were captured over nine years. Nearly half of them were caught for the initial two years, during which the pond was drained. Thereafter, the annual catch of RES turtles clearly decreased. These results suggest that it is difficult to control RES turtles established in rivers but that it is feasible to effectively control RES turtles in enclosed small water bodies, such as irrigation reservoirs, by intensively capturing and eliminating the turtles during the drainage period.

Dynamics of the parasitofaauna of roach Rutilus rutilus (Linnaeus, 1758) since the beginning of the existence of the Boguchanskoye reservoir

This article presents the results of parasitological studies of roach Rutilus rutilus (Linnaeus, 1758) in Boguchanskoye reservoir, the stages of parasite fauna formation and the current state of the reservoir. Ichthyofauna of Boguchanskoye Reservoir was formed by local fauna of Angara River. Transformation of the original reservoir has led to significant changes in the composition and community structure of all groups of organisms of aquatic biota and affected the parasite fauna of fish. Over eight years (2012–2020), 35 species of parasites from 9 classes were recorded in roach in Boguchanskoye Reservoir. Originally, the composition of parasites was not diverse and had few specific species. Most parasites had low or single occurrence. Trematode metacercariae predominated, and their quantitative indicators (extensity of infection and index of abundance) indicate the ecological confinement of fish to shallow river sections. After impoundment, the parasite fauna composition became more diverse due to parasitic protozoa and monogeneas. Currently, the proportion of parasites with a direct development cycle is 68.2%. In 2020, two types of helminths were registered with a plankton development pathway: Ligula intestinalis Linnaeus, 1758 and Philometra rischta Skrjabin, 1917. The species Ph. rischta — first detected in fish in water bodies of Krasnoyarsk Region. There was a change in the dominant species, Dactylogyrus crucifer (Wagener, 1857) became the dominant species.

Towards a better understanding of the evaporative cooling of rivers: case study for the Little Southwest Miramichi River (New Brunswick, Canada)

Stream temperature plays an important role in many biotic and abiotic processes, as it influences many physical, chemical, and biological properties in rivers. As such, a good understanding of the thermal regime of rivers is essential for effective fisheries management and the protection of aquatic habitats. Moreover, a thorough understanding of underlying physical processes and river heat fluxes is essential in developing better and more adaptive water temperature models. Very few studies have quantified river evaporation and rivers’ corresponding evaporative cooling component. The present study investigated the evaporative cooling of the Little Southwest Miramichi River in Eastern Canada by calculating the evaporative heat flux and overall heat fluxes using in-situ data. Results showed that the evaporative heat flux reached −300 W m−2 mid-day when high water temperatures were observed. The daily evaporative heat flux can thus account for close to 50% of the total heat losses, followed by longwave radiation (25%), streambed heat fluxes (20%), and sensible heat (5%). Our results show that the evaporative heat flux can be a critical cooling mechanism for wide and shallow rivers during high summer temperatures.

Implementation of a Full-scale Circular Constructed Wetlands to Treat Greywater at Natural Tourism in Malang, Indonesia

This research examines a circular-shape constructed wetlands (CCW) system at Bedengan Camping Site (BCS) as Natural Tourism in Malang, Indonesia. There are family fun-park, shallow rivers, and camping grounds at BNT as a tourist attraction. The CW system was built in 2021 and used to treat greywater from public toilets, food courts, and cafes. This study aims to demonstrate the performance of the CW system in treating greywater to meet the standard limits of the treated wastewater. The CW was arranged in a circular shape to follow the contour of the land, and three water plants such as Canna, Heliconia psittacorum, and Equisetum hyemale planted for the CW treatment. A sampling of wastewater took place during covid-19 pandemic and after the pandemic from three sampling ports: the sedimentation tank, inlet of CCW, and outlet of CCW. The results show that the CCW system performs well in reducing organic pollutants from greywater produced by visitors and meets the domestic wastewater threshold limit as stated in the Ministry of Environment and Forestry Regulation No. P.68/2016. The average of the organic pollutant removals was higher than 90%, while the pH of the treated water changed from acid to neutral condition. It is assumed that the CW system can provide a neutralisation process of the greywater at BCS.

The Admiralty Plant on the Shirsha: A Road to Nowhere

The Admiralty plant on the river Shirsha, located 20 versts upstream of Arkhangelsk along the Northern Dvina, was the largest enterprise of the naval authority in the Russian North that filled the demands of the Arkhangelsk Admiralty, located in Solombala, in the foundry and metalwork productions as well as in timber. The number of the plant’s workmen used to be up to 250 people, with the total staff number of up to 370 officers and lower ranks. The main problem of the plant was the low capacity of its machines, as the main source of energy was the water from the local shallow rivers. In addition, there were no mechanical engineering facilities in Shirsha, which made it impossible to manufacture machinery for steam-powered vessels under construction. For propulsion systems to be installed, they had to travel around Scandinavia to the Kronstadt docks. The boilers, too, were often brought from St. Petersburg or from other factories. Another serious issue was the complicated logistics for delivering finished products directly to the Admiralty. To address this issue, the naval authority experts proposed to move the plant facilities directly to Solombala to drastically reduce transportation costs and use available and planned steam engines. During the preparation of the Arkhangelsk Admiralty for closing down it was originally planned to hand over the plant to a private owner but these projects were buried in 1862. The plant was closed down and the remaining assets were sold.

Flavobacterium potami sp. nov., a multi-metal resistance genes harbouring bacterium isolated from shallow river silt

Environmental pollution by heavy metals is becoming an increasing problem and has become a matter of great concern due to the adverse effects worldwide. In this study, we report a novel strain of multi-metal resistant bacteria. A Gram-stain-negative, strictly aerobic, non-motile, yellow, rod-shaped strain 17AT, was isolated from the shallow silt of Fuyang River located in Longdian town, Hengshui city, Hebei province, China. Strain 17AT grew at 20-35°C (optimum, 30°C), pH 5-10 (optimum, pH 7) and 0-2% (w/v) NaCl (optimum, 1%). Phylogenetic analyses of 16S rRNA gene sequences showed that strain 17AT was closely related to members of the genus Flavobacterium, and had the highest 16S rRNA gene sequence similarity with 'Flavobacterium panacis' DCY106T (97.5%), followed by Flavobacterium johnsoniae subsp. johnsoniae UW101T (97.3%), Flavobacterium cutihirudinis E89T (97.2%), Flavobacterium limi THG-AG6.4T (97.2%), Flavobacterium hibisci THG-HG1.4T (97.2%) and Flavobacterium johnsoniae subsp. aurantiacum DSM 6792T (97.1%). The genome size of strain 17AT was 5.4Mb and the DNA G + C content was 34.0%. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values among strain 17AT and reference strains were in the ranges of 79.8-86.1%, 24.1-31.4% and 80.5-88.6%, respectively, lower than the threshold values for species delineation. Strain 17AT contained iso-C15:0 and C16:0 3-OH as the predominant fatty acids (≥ 10%). The main isoprenoid quinone of strain 17AT was identified as MK-6. The polar lipids consisted of phosphatidylethanolamine, three unidentified aminolipids, two unidentified aminophospholipids and six unidentified lipids. Comparative genomics analysis between strain 17AT and its reference type strains revealed that there are a number of metal-resistant genes in strain 17AT, which are located in 15 gene clusters responsible for the copper homeostasis, cobalt-zinc-cadmium resistance, copper resistance, and arsenic/antimony resistance, with the copper resistance protein NlpE being unique to 17AT. Combined data from phenotypic, phylogenetic and chemotaxonomic studies demonstrated that strain 17AT is a representative of a novel species within the genus Flavobacterium, for which the name Flavobacterium potami sp. nov. is proposed. The type strain is 17AT (= GDMCC 1.2723T = JCM 34833T).

Contrast Analysis of Flow-Discharge Measurement Methods in a Wide–Shallow River during Ice Periods

The discharge of natural rivers is one of the important hydrological factors that are considered when responding to ice-flood disasters during ice periods. Traditionally, holes need to be dug along the cross-section on the ice cover to gauge velocity distributions along the flow depth at each hole, and to calculate the cross-sectional flow discharge by integrating velocity profiles over the entire area. This method is time consuming, costly, and inefficient. The discharge measurement can be improved using the sectional flow-depth distribution and stream-tube methods. However, the selection of both the depth-averaged–velocity-estimation method and the typical survey-point position in the cross-section affects the estimation accuracy. This study first compared the estimation methods of the depth-averaged velocity, such as the one-, two-, three-, and six-point methods, and their estimation accuracy. Furthermore, the variations in relative-unit discharge distributions in common channels with cross-sectional topographies were analyzed, and the effects of the cross-section characteristic coefficient and typical survey-point position on the flow-discharge estimation accuracy were compared. The results show that the average errors of the depth-averaged velocity estimated by the one-point method at 0.5H, new three-point method, and six-point method were 1.96%, 1.22%, and 0.45%, respectively. The new three-point method is recommended if measurement workload and accuracy are key considerations. The cross-section characteristic coefficient is considered to be 0.5 and 0.25 for the natural river and artificial channel, respectively, and the maximum-flow-depth position in the mainstream area of the cross-section is selected as the typical survey-point position. Thus, the flow-discharge estimation accuracy can be improved. In conclusion, this study provides an improved stream-tube method for the measurement of flow discharge and velocity distribution in ice periods, which can be used as a reference during practical applications.

IDENTIFIKASI PENYEBAB DEADFREIGHT MUATAN BATUBARA DI MV. RB MYA

Muara Berau Anchorage is one of the waters in East Kalimantan that many ships visit for coal loading and unloading activities. The coal export transhipment was carried out in the Berau Estuary, Samarinda because the draft of large ships did not allow it to enter the far and shallow river channel. In the execution of loading there is often a shortage of load caused by several factors. The purpose of the study is to determine the causes and impacts of load deadfreight and efforts to reduce the occurrence of load deadfreight in the coal loading process. The methods used are descriptive qualitative. Data were collected through observation, interviews and literature studies that were tested for validity and reliability tests. The results of this study show that the cause of the load deadfreight in the MV. RB MYA is the theft of cargo along the Mahakam river, spillage of coal cargo during the loading process, and lack of supervision in the loading process at the Jetty. The impact of the deadfreight of coal cargo is the occurrence of a shortage of shiploads and the occurrence of losses for shippers. Efforts were made to reduce the occurrence of payload deadfreights in the MV. RB MYA is to hold barge escorts, increase the effectiveness of communication between the ship and floating cranes, and increase the number of Foreman Jetty.

Enhancement of energy capture by flow induced motion of a circular cylinder using passive turbulence control: Decoupling strip thickness and roughness effects

Passive turbulence control of flow induced motion of a cylinder using strips has been practiced for over 30 years. The two distinct physical characteristics of strips: thickness and roughness, can have coupled effects on altering the flow induced motion. The experimental work discussed here decouples these two effects for augmented energy extraction. Tests with cylinders attached with strips of roughness varying from 0% to 100%, and thickness varying from 0.8% to 8.2% of the cylinder diameter, were performed (5000 < Re < 35600). The dynamic response of the configurations with rough strips was compared to that with smooth strips of same thickness. Mechanical power and energy transfer efficiencies were evaluated to analyze the power extraction potential of different configurations. Power generated by the smooth strip configurations was 1.25–5 times higher depending on the roughness ratio and flow velocity. Smooth strips also provided more operational stability, characterized by smaller values of the coefficient of variation of power and concentrated non-dimensional force-velocity states. These devices are the more efficient adaptation from an energy harvesting perspective at low velocities (<1.0 m/s), a range below the cut-in speed for most hydrokinetic turbines, thereby making energy extraction feasible from shallow rivers and slow-flowing streams.

STRATEGI BPBD KABUPATEN PACITAN DALAM UPAYA PENANGGULANGAN BENCANA BANJIR DAN TANAH LONGSOR

This study aims to determine the condition of natural disasters such as floods and landslides and the efforts of BPBD to overcome them. The research was conducted in Pacitan City on the basis of the consideration that floods and landslides are common in this area. Data was collected through open interviews, observation, and document review, then the data were analyzed descriptively qualitatively. The results showed that the condition of the Pacitan City area consists mostly of highlands in the form of steep mountains and shallow river areas so that it is very vulnerable to natural disasters in the form of floods and landslides, especially during the rainy season. The flood natural disaster that occurred in Pacitan City was mainly caused by the silting of the riverbed and the narrowing of the river's width. Meanwhile, landslides are caused by erosion caused by rainwater and the increasing number of residential areas that make the foot of the slope increasingly eroded. Efforts made by BPBD to overcome natural disasters of floods and landslides that occurred in Pacitan Regency were by launching various forms of strategies such as the DESTANA program, Socialization, Procurement of Disaster Simulations, Construction of Embankments, Installation of Information Signs for Disaster-Prone Areas, Map-making of Disaster-Prone Areas and Determination of Evacuation Areas, and Mangrove Planting. The various strategies implemented also serve to increase public awareness and preparedness for disasters.

Drone-Based Bathymetry Modeling for Mountainous Shallow Rivers in Taiwan Using Machine Learning

The river cross-section elevation data are an essential parameter for river engineering. However, due to the difficulty of mountainous river cross-section surveys, the existing bathymetry investigation techniques cannot be easily applied in a narrow and shallow field. Therefore, this study aimed to establish a model suitable for mountainous river areas utilizing an unmanned aerial vehicle (UAV) equipped with a multispectral camera and machine learning-based gene-expression programming (GEP) algorithm. The obtained images were combined with a total of 171 water depth measurements (0.01–1.53 m) for bathymetry modeling. The results show that the coefficient of determination (R2) of GEP is 0.801, the mean absolute error (MAE) is 0.154 m, and root mean square error (RMSE) is 0.195 m. The model performance of GEP model has increased by 16.3% in MAE, compared to conventional simple linear regression (REG) algorithm, and also has a lower bathymetry retrieval error both in shallow (&lt;0.4 m) and deep waters (&gt;0.8 m). The GEP bathymetry retrieval model has a considerable degree of accuracy and could be applied to shallow rivers or near-shore areas under similar conditions of this study.

Waterbird assemblage along Punatsangchhu River, Punakha and Wangdue Phodrang, Bhutan

Crossing Bhutan is one of the shortest transits, and Bhutan holds the main breeding refuge/habitats for many Central Asian migratory birds. Our study assessed the community structure of waterbirds along the Punatsangchhu River basin, located towards the western part of Bhutan. The study determined the species composition, habitat use and preference of waterbirds, together with the different habitats present. Furthermore, the study examined the potential drivers of habitat fragmentation along the river. The entire study area was classified into five different habitats: dam, dredged area, farmland, urban, and pristine. The Cummings method of habitat assessment for high gradient river and streams was used to assess the habitat variables such as bank stability, vegetative protection and the riparian vegetation zone along the river and the association with the diversity of aquatic birds. A questionnaire survey was also used to evaluate the degree of threats caused by human disturbances. Among the five habitats, the dam area recorded the highest diversity (H` = 2.13) against their total count of 103 (8.7%) and the least diversity was recorded from farmland area (H` = 1.1) against their total count of 282 (23.8%) birds. Most waterbirds preferred an open area with shallow river depth. Habitats with emergent vegetation negatively correlated with the waterbird species composition. The study also recorded one Vulnerable species Aythya ferina, one Near Threatened species Vanellus duvaucelii, and one Endangered species Haliaeetus leucoryphus. Punatsangchhu is a major habitat to both resident and migratory waterbirds which stop here enroute from the Palaearctic and Indo-Malayan Region corroborating the need for habitat conservation and management regimes in the basin.

Image-based migration velocity and dune length in clear water rivers

This work presents a novel way of measuring image-based migration velocity and dune length in clear water rivers. These results, together with empirical formulations, can be used to estimate bedload sediment transport with a high-spatial resolution. Image processing relies on the non-intrusive image-based technique called Space-Time Image Velocimetry (STIV). STIV consists in visualizing pixel intensity variation in time over a defined line. This technique was originally applied to hydraulics in order to characterize streamwise surface velocities in rivers. In this case, STIV is used to measure dune migration velocity and length in a shallow river with clear water in Córdoba Province, Argentina. Image processing procedures are detailed, including pre-processing and rectification. Results are then compared with measurements obtained from Acoustic Doppler Current Profilers. Finally, as an appendix, using the measured data and empirical equations, an estimation of bedload sediment transport is performed using both techniques.

Mapping Underwater Bathymetry of a Shallow River from Satellite Multispectral Imagery

Rivers play an important role in water supply, waterway transport, and riverine species habitations. The underwater depth of a river channel is a fundamental geometric element and a key input to studies for the aforementioned and other applications. Traditional in-situ field surveys for flow depth measurements would incur high costs and encounter technical and/or logistical difficulties, particularly for river channels of large extents, very shallow channels, and remote, inaccessible channels. Recent advances in satellite remote sensing of inland water bodies like rivers, streams, and creeks have allowed mapping flow depth in an inexpensive, convenient, and efficient manner. The purpose of this paper is to demonstrate the retrieval of river flow depth from high-resolution (1.2 m) WorldView-3 satellite imagery. The depth retrieval methods are based on the ratio of top-of-atmosphere reflectance between two pairing wavelength bands of multispectral imagery. The originality of the methods lies in using analytical relationships without resorting to ground data of river flow depth for calibration, which improves from previous studies of remote sensing of river flow depth. The methods are successfully applied to mapping the underwater bathymetry of a 26 km reach of the Nicolet River in Quebec, Canada. This study shows the importance of geometric and radiometric corrections to the satellite images. The obtained flow depths using the ratio of reflectance of the red band (630–690 nm) to that of the green band (510–580 nm), among the eight bands in the visible spectrum, agree best with in-situ measurements. This study is perhaps the first use of the analytical approach for mapping river bathymetry. It is feasible to implement the approach to other river channels, with a good potential to reduce the costs and increase the efficiency of mapping river bathymetries.

Challenges with Regard to Unmanned Aerial Systems (UASs) Measurement of River Surface Velocity Using Doppler Radar

Surface velocity is traditionally measured with in situ techniques such as velocity probes (in shallow rivers) or Acoustic Doppler Current Profilers (in deeper water). In the last years, researchers have developed remote sensing techniques, both optical (e.g., image-based velocimetry techniques) and microwave (e.g., Doppler radar). These techniques can be deployed from Unmanned Aerial Systems (UAS), which ensure fast and low-cost surveys also in remotely-accessible locations. We compare the results obtained with a UAS-borne Doppler radar and UAS-borne Particle Image Velocimetry (PIV) in different rivers, which presented different hydraulic–morphological conditions (width, slope, surface roughness and sediment material). The Doppler radar was a commercial 24 GHz instrument, developed for static deployment, adapted for UAS integration. PIV was applied with natural seeding (e.g., foam, debris) when possible, or with artificial seeding (woodchips) in the stream where the density of natural particles was insufficient. PIV reconstructed the velocity profile with high accuracy typically in the order of a few cm s−1 and a coefficient of determination (R2) typically larger than 0.7 (in half of the cases larger than 0.85), when compared with acoustic Doppler current profiler (ADCP) or velocity probe, in all investigated rivers. However, UAS-borne Doppler radar measurements show low reliability because of UAS vibrations, large instrument sampling footprint, large required sampling time and difficult-to-interpret quality indicators suggesting that additional research is needed to measure surface velocity from UAS-borne Doppler radar.

Water Column Microbial Communities Vary along Salinity Gradients in the Florida Coastal Everglades Wetlands.

Planktonic microbial communities mediate many vital biogeochemical processes in wetland ecosystems, yet compared to other aquatic ecosystems, like oceans, lakes, rivers or estuaries, they remain relatively underexplored. Our study site, the Florida Everglades (USA)—a vast iconic wetland consisting of a slow-moving system of shallow rivers connecting freshwater marshes with coastal mangrove forests and seagrass meadows—is a highly threatened model ecosystem for studying salinity and nutrient gradients, as well as the effects of sea level rise and saltwater intrusion. This study provides the first high-resolution phylogenetic profiles of planktonic bacterial and eukaryotic microbial communities (using 16S and 18S rRNA gene amplicons) together with nutrient concentrations and environmental parameters at 14 sites along two transects covering two distinctly different drainages: the peat-based Shark River Slough (SRS) and marl-based Taylor Slough/Panhandle (TS/Ph). Both bacterial as well as eukaryotic community structures varied significantly along the salinity gradient. Although freshwater communities were relatively similar in both transects, bacterioplankton community composition at the ecotone (where freshwater and marine water mix) differed significantly. The most abundant taxa in the freshwater marshes include heterotrophic Polynucleobacter sp. and potentially phagotrophic cryptomonads of the genus Chilomonas, both of which could be key players in the transfer of detritus-based biomass to higher trophic levels.

大兴安岭南段马鹿生境适宜性分析与生态廊道构建

PDF HTML阅读 XML下载 导出引用 引用提醒 大兴安岭南段马鹿生境适宜性分析与生态廊道构建 DOI: 10.5846/stxb202109062517 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 赤峰市林业科技振兴计划项目 Habitat suitability analysis and ecological corridor designs for red deer (Cervus elaphus) in the southern Greater Khingan Mountains Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:构建生态廊道在缓解生境破碎化对生物多样性的影响、维持濒危物种的遗传多样性、维护自然生态系统结构完整与功能稳定方面具有重要作用。以内蒙古大兴安岭南段分布的马鹿（Cervus elaphus）种群为研究对象，利用MaxEnt模型对其生境适宜性进行分析，并利用最小累积阻力模型构建潜在生态扩散廊道，探讨大兴安岭南段区域隔离马鹿种群的栖息地连通方案。结果显示，马鹿栖息地呈破碎化状态，种群有明显的隔离分布趋势，现有适宜栖息地具有海拔较低（800-1200 m）、坡度较缓（<15°）、靠近水源、植被类型多为靠近山林的灌丛或草地等特点。所构建12条生态廊道具有经过河流浅水节段、远离村落等特点，便于落实栖息地生态恢复管理措施。研究从区域尺度综合分析了大兴安岭南段马鹿栖息地现状及连通性，有助于优化适宜栖息地格局，促进马鹿扩散和栖息地连通，为该物种隔离种群及其栖息地保护规划提供现实指导和基础资料。 Abstract:Effectively designed ecological corridors can eliminate the impact of habitat fragmentation on biodiversity, promote gene flow and the genetic diversity of endangered species, and maintain the structural integrity and functional stability of natural ecosystems. In this study, we used the MaxEnt model to analyze habitat suitability for red deer (Cervus elaphus) in the southern Greater Khingan Mountains, Inner Mongolia. We created a minimum cumulative resistance model to identify potentially ecological corridors for red deer. Results showed that red deer habitats in the study area were fragmented. The red deer population had an obvious trend of isolation distribution; the existing suitable habitats were characterized by low elevation (800-1200 m) and a gentle slope (<15°) close to a water source, and the suitable habitats mostly consisted of forest shrub or grassland vegetation close to woodland edges. The creation of 12 ecological corridors would encourage red deer dispersal and support habitat connectivity. Three main characteristics of the corridors that were conducive to habitat restoration management measures include-passing through shallow rivers, irregular topography, and being located far away from human residences. The comprehensive analysis of habitat suitability and ecological corridors from a large-scale perspective may help optimize red deer habitat distribution. The analysis can provide practical guidance and basic information for the conservation of the species in the southern Greater Khingan Mountains. 参考文献 相似文献 引证文献

Sediment Removal from Deep Reservoir Dams by Suction and Jet Flow

One method of sediment removal from dam reservoirs is the use of submerged pumps and suction mixes of sediment and water. This method is usually considered for shallow rivers but we want to adopt this method for large dams. In this research, a system based on suction with a submerged pump structure is designed to collect fine sediments close to body of the dam from a large depth and to be transmitted by floating pipes to the margin of lake. And also, by pumping of jet fresh water flow and creating turbulence by the jet on sedimentary bed is simultaneously used to increase harvesting efficiency. The usage of simple equipment for removing fine grains near the dam body without the need for discharging of water resources is one of the essential features of this method which is suitable for arid and dry areas such as Iran. By using turbulent flow of water jet and simultaneous suction with a submerged pump, a vortices stretch is produced to suction the sediment mixture. Overall, the discharged sediment separates from water on the margin of lake to restores water to the reservoir.

Anatomy, and: Afterlife

Anatomy, and: Afterlife Yuki Tanaka (bio) Anatomy Shallow river with my right foot in it.The river has no fish, but a dozen sundown snakesnibble at my toes. I feel no poison. I am strong.My toenails hang onto me like lovers.When I am tired, I leap up to relax the muscles or squatto dip my buttocks in the water. My left foot divesin the river, like a child. The bright snakes welcome him.Under the watery roof, my feet are brother and sister.From their viewpoint, my face is smooth as otter skin,which gives me the confidence to say, You are both invited.Man with a liquid face, they call me, but refuse to come out.My face streams, carrying dirt.The evening turns my eyes to geranium.I gulp to beautify my voice, and say, Come home.They whisper, He can’t get his own feet back,is he a ghost.Having no feet, he must miss the smell of crushed grass. [End Page 5] Afterlife 1 my body thinnedto a mirror reflecting others backmrs mashino stumbled and felland I helped her up saying you are a scarecrowtumbled by a flood she said she was and I felt badI should have said, You were happy on the cloudand fell down with heavy thoughtshow her mood shifted from rain to storm to magnoliaher small face had a pockmarked cheekbut sweat made it a beautiful riverbankmice music from the buoysunbraided hair her fireworksdon’t feed stray cats or they’ll make light of youshe had the voice of grassand I imitate the wind passing through herhaha she laughs haha I echomingled with the shells of Ishikawa [End Page 6] 2 I wait for her returnsitting in the distance of forty pebblesslow rain from the iciclesit is windlessthe horse hoof print becomes a sunlit poolmy tree blooms and bears plumsand lets them falllike guests knocking on earth unable to come indoes that mountain have a chinwhere a bird could perch and tickle himif the mountain speaks upthe bird is shaken off and needs to find a homemy smoothed arm is a desirable branchcome fly to touch meare you too a reincarnatoryou have that forsythia look [End Page 7] Yuki Tanaka yuki tanaka holds an mfa in poetry from the Michener Center for Writers and a PhD in English from Washington University in St. Louis. His chapbook, Séance in Daylight (Bull City Press), was the winner of the 2018 Frost Place Chapbook Contest. He teaches at Hosei University in Tokyo. Copyright © 2022 Yuki Tanaka

THE MALE OPILLIA MORPHOLOGICAL ANALYSIS OF RELIEF

The Male Opillia morphological analysis of relief has been carried out on the basis of constructed morphological maps on the scale of 1:50 000 for the key part of the Zubra – Sukhodilka watershed. The morphological mapping lies in taking into consideration dotted, linear and areal elements of relief. The absolute heights of the study area are between 255 and 405 meters high (highland level – 330-405 m, lowland level (main valleys) – 255–290 m). The relative heights of the Zubra River Basin are between 50 and 100 m, Davydivka–Sukhodilka River Basin – between 70 and 130 m. Four main linear elements of relief are thalwegs, combes, convex and concave bends. The most common linear elements are thalwegs. They are the bottoms of shallow river valleys, arroyos, and largest gullies. The main direction of linear reach is diagonal (NW–SE). The convex bends delineate the highland surfaces and flats. They also separate gentle watershed slopes from steep valley slopes. The concave bends usually are the borders of greater river valleys. These elements of relief are entirely isolated, which demonstrates a discernible contact between slopes and bottoms. The combes are the least common linear elements. It is connected with the roundness and alignment of highland surfaces and a small number of sudden changes of directions of horizontals on the straightforward slopes. The dotted elements of relief are submitted as high points. Most high points are rounded. The areal elements of relief are submitted as highland (watershed) surfaces, flats, bottoms of valleys, and different shapes of slopes, according to the cross-section and plan. The highland surfaces are quite noticeable. Their absolute height is estimated between 350 and 380 m. The highland surfaces don’t occupy the upper parts of interfluves; they are divided into two parts. The shape of highland surfaces is strongly stretched along. The nature of morphology of the surface of relief is weakly curved and flat according to the cross-section, and weakly curved and wavy according to the longitude. The surfaces of the flats are subhorizontal elements of relief, which are an intermediate position in relief. These surfaces are bounded by one or two concave bends. The bottoms of the valleys of the Zubra are 190–770 m in width, the Davydivka – 190–770 m, the Sukhodilka – 140-820 m. The shape of the cross-section is predominantly flat, and only in shallow valleys it’s partly concave. The slopes occupy much of the study area so that they prevail over subhorizontal surfaces. The convex slopes prevail; the least common are concave slopes. Key words: morphological analysis of relief; morphological map; elements of relief; Male Opillia.