Development of a noncontact liquid level measuring system using image processing

This paper describes how the authors developed a liquid level measuring system designed to directly analyze images of liquid surfaces. This measuring system is based on the principle that the contour of the image of a slanted metal strip placed in a liquid shows an inflection point on the liquid interface. This liquid level measuring system using image processing is useful in automatically measuring the levels of water, oil, liquefied gases, and alcoholic beverages. Among the features of this measuring system are: (1) it is of the noncontact type, so that there is no need to install a sensor or other high-precision devices close to the liquid to be measured; (2) it can be installed in a way not affected by the liquid; (3) the scale and the liquid surface can be analyzed on an image basis directly, so that periodic recalibration is unnecessary; (4) deviations in measurements can be easily detected by visually checking the monitor screen; (5) images from more than one camera can be processed with a single image processor to reduce total costs.     

Peak operation of a hydroelectric station as a factor in formation of backflow in a lateral tributary

Conclusions Peak operation of an HES is capable of leading to formation of backflow in a tributary emptying into its lower pool. The flow characteristics (rate, duration) can be found from data on fluctuations in level with the use of the suggested schemes. As applied to the confluence of the Desna and Dnepr, we can conclude that in ordinary operating conditions of the Kiev HES it is practically impossible for Dnepr water to reach the existing or planned water intakes.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 9, pp. 22–26, September, 1994.     

Bidirectional connectivity via fish ladders in a large Neotropical river: Response to a comment

In a recent article, we described fitting electronic tags to the fish Prochilodus lineatus to document how a fishway connected aquatic habitats downstream and upstream of a major dam. Moreover, given that tagged fish remained upstream or downstream for periods extending months and years before returning to the fishway, and that observed patterns of passage were consistent with seasonal migratory cycles, and building on existing literature, we speculated that the fishway allows fish access to spawning habitats upstream and feeding habitats downstream. Our interpretation of the movement data resulted in several comments from Pelicice, Pompeu, and Agostinho (2020) and they outline various reasons by which, in their opinion, some of our conclusions may be mistaken. Their critique is threefold. First, they argue that the percentage of fish attracted into the fishway is too low to consider the fishway an effective link between the reservoir and the river downstream. We contend that without estimates of population size it is impossible to judge if 28% passage is “limited”; conceivably, the absolute number of fish passed may still be enough to maintain a viable population. Second, they assert that because receivers were located only in the fishway it is unknown if fish that used the fishway remained near the dam, or if they continued their migration. We counter with a brief literature review that documents P. lineatus migrating through reservoirs and spawning in tributaries. Third, they advocate for a broader conservation perspective and for additional research. We agree and, in the article, had already expressed this view that fishways are only a temporary fix and that we support their use only as an element of a broader environmental management package. We also agree with the need for more research but argue that procrastinating on conservation action may not be wise because we do not know if the research will be done, how long it will take, or what the cost may be of waiting.     

溢洪道泄槽弯道设置导流墙试验研究

通过对实际工程的模型试验,验证了在溢洪道泄槽弯道段上设置导流墙工程措施的合理性,介绍了该工程措施的设计方法:导流墙一般布置在弯道轴线上,起始位置与弯道开始位置相同;导流墙长度可等于或略大于弯道轴线长度,高度可按抬高泄槽底高度Δh的1.0~1.1倍取值;导流墙一般应采用钢筋混凝土结构;导流墙断面形式可采用矩形,因导流墙顶部可以过水,顶部宜做成梯形或半圆形.     

Characteristics and evaluation of the state of concrete dams operating for a long time

Conclusions The reliability of concrete dams should be evaluated by comparing the observed monitored parameters related to criteria of the safe state and reliable operation of structures with the maximum allowable values of these parameters.The maximum allowable values of the monitored parameters are determined in the basis of retrospective calculations of the structures and on the basis of a comprehensive analysis of the data of long-term instrument and visual observations. The maximum allowable values of the monitored parameters can be expressed both by quantitative and qualitative quantities.In the case of insufficient information for evaluating the state of a long-operating structure and its further reliable operation, it should be equipped with additional MME and in certain cases special experimental investigations should be conducted on it.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 4, pp. 17–19, April, 1995.     

灌溉管路用快速连接件产品的研制及其水力性能

在现有各类连接件结构的基础上,设计出一种灌溉管路用快速连接件产品,该产品整体结构设计合理,操作简单方便,具有快速组装与拆卸的特点,实现了插入自动通水、拔移自动断水的功能。分析快速连接件产品的结构组成和工作原理,并进行水力性能测试。测试结果表明:快速连接件产品具有过水流量稳定、局部水头损失小、插拔灵活性强、密封性能优等特点,能起到降低系统投资和提高工作效率的作用,适用于移动灌溉和抗旱灌溉工程。     

Modeling oxygen-supply depletion in a local region of a reservoir subjected to wind-generated pile up and decomposition of a phytoplankton mass

Conclusions  1. A procedure is proposed for possible use in calculating oxygen-supply depletion in a local area of a reservoir (gulf, bay, near-dam section) with wind-generated pileup and decomposition of a phytoplankton mass, and also for assessing the conditions of this depletion (trophicity of the reservoir, wind speed, direction, and duration, etc.). 2. The size of the local area (section) of the reservoir can be selected arbitrarily, but with allowance for the morphometric characteristics of the reservoir and the specifics of the problem being solved, which consists in the fact that assessment of conditions of oxygen-supply depletion in any section of the reservoir is probabilistic, i.e., ambiguous, in nature. Depletion of the oxygen supply can therefore be calculated for various conditions, including the dimensions of the section, but principally for wind conditions, which in final account, also determined the indicated estimate. 3. The proposed method makes it possible to predict the probability of an ecologically dangerous depletion of oxygen supply in a reservoir; this is illustrated in an example of the Verkhneupinsk Reservoir currently under design. Such a prediction may serve as the basis for the development of methods to reduce the eutrophication level of a reservoir and control the quality of its water to prevent starvation phenomena. Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 5, pp. 43–49, May, 1998.     

Application of a Hydrologic Model Considering Rainwater Storage to Analyze Storm-induced Landslides in a Forest Catchment

In this study, a conceptual hydrologic model was applied for the analysis of storm-induced landslides, which were affected by typhoons in 2004, in the forest catchments of Ehime Prefecture, Japan. Through the model, hydrologic conditions such as rainfall intensity, rainwater storage, and soil moisture behavior in 2004 were obtained and compared with other 19 years (1985 ∼ 2003). Furthermore, the relationship between landslide occurrence and hydrologic phenomena in the catchments were assessed. Results of this study indicated that soil moisture, excess rainfall storage combined with rainfall intensity, and its duration in the forest were the key elements for the occurrence of landslides. The hydrologic model in this study was able to represent hydrologic phenomena reasonably and it can be used for the estimation of discharge, soil moisture content, and water storage in catchments. The concept of this model is available to be applied in other areas and can be expected to provide important information on soil moisture behavior for forecasting and preventing landslide disasters.     

Characteristics of pressure fluctuations beyond spillways with a ledge

Conclusions When calculating the intensity of pressure fluctuation on a revetment for the surface regime beyond a dam with a ledge by the appropriate relations [3] it is necessary to take into account that the dispersion of the turbulent component given by this calculation is commensurate with the dispersion of the wave component of presssure fluctuation, which presently can be determined from the results of hydraulic investigations. The data given in [5] can be used for estimating the intensity of the total value of pressure fluctuation on a revetment for a surface regime beyond a dam with a ledge under conditions of the two-dimensional problem and in the range of relative heights of the ledge d/h_c=3–6.5 and Froude numbers in the vena contracta on the ledge Fr_c=8–50.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 3, pp. 26–28, March, 1986.     

Regulating the temperature regime of water in the lower pool of a hydroelectric station

Conclusions An analysis showed that the water intakes for selective withdrawal of water from a reservoir for water-supply purposes known from the scientific and technical literature cannot be used effectively for withdrawing a large quantity of water for hydrostation turbines, and the known intakes for selective withdrawal of a large quantity of water have substantial shortcomings and are in need of further design improvement. Simultaneously with this, the conclusions of the 1993 Divnogorsk conference that at present “it is impossible to freeze the Yenisei River within the Krasnoyarsk city limits” for a number of reasons is confirmed. However, under more favorable conditions than the Krasnoyarsk hydrostation, the selective withdrawal of water from a deepwater intake for hydrostation turbines, despite the high additional expenditures, can be justified and necessary. The proposed design of a floating intake of an electric power station has a number of advantages compared with the known floating intakes. In this case it recommended to direct the water that is withdrawn from the surface layer of the reservoir and passed only through one or two turbines to save expenditures to the bank part of the river, which promotes in the lower pool the formation of ice near the river banks and in its branches in the winter and their “warming” in the summer. Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 9, pp. 46–49, September, 1997.     

The Potential for Calculating a Meaningful Water Poverty Index

Abstract

One of the most significant failures in the development process has been our inability to match water demand to its supply. For a large portion of the world's population, this has meant a lack of provision of adequate water for domestic use, resulting in a significant loss of time and effort, especially on the part of women. While science can now provide us with detailed assessments of water resource availability, little to date has been done to link this to our knowledge of human resources and their geographical distributions. In order to manage these resources better, it is essential that they be addressed in a more holistic way. This paper provides a preliminary discussion of possible ways in which an interdisciplinary approach can be taken to produce a more holistic assessment of water stress, in such a way as to link physical estimates of water availability with the socio-economic drivers of poverty. To this end, some approaches to creating a Water Poverty Index are discussed, and it is hoped that this paper will generate interest and debate among a wide range of readers.     

Short-term flood routing in reserve storages of a stream

Conclusion Equations (6) and (7) make it possible to determine the dynamics of the change in the discharge and its maximum value at any site on the stream. Depending on the location of the control site and hydraulic parameters of the stream, the calculation can be considerably simplified without detriment for solving engineering problems.The proposed method of calculating flood characteristics makes it possible to rather simply find, during design, the rate of change in discharges at control sites with consideration of the main hydraulic parameters of a stream and duration of the shower for determining the speed of response of gate operation on intake works.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 11, pp. 40–42, November, 1991.     

Occurrence of a Cylindrospermopsis bloom in Louisiana

Cylindrospermopsis raciborskii occurs predominantly in tropical to subtropical freshwaters but appears to be spreading to temperate regions. After the hurricanes of 2005, a bloom of this organism took place in Lake Dauterive and Lake Fausse Pointe in Louisiana. The cyanobacterium dominated the phytoplankton community for three months. Of the three known morphotypes (straight, coiled and spiral) only coiled and spiral were found. In June 2006, 60% of the organisms were of the spiral morphotype but the relative abundance of this morphotype decreased dramatically within the month of June. However, the average density for both morphotypes remained the same until September. Densities (up to 160,000 cells/mL) significantly exceeded the threshold for toxicity. Because the sampled region offers optimal light and nutrient conditions, it is likely that C. raciborskii has been established in this region and future blooms can be expected. Therefore, a monitoring program should be implemented.     

某大坝沥青混凝土心墙变形监测分析与探讨

以工程实际监测资料分析为基础,经分析确定正位错大小与大坝心墙压应力无必然关系;因而提出：应提高过渡料填筑压实标准以减少心墙竖向变形,岸坡处理应尤为如此;并建议应采用更先进的光纤维传感技术加密对心墙的变形及变形量进行三维空间定位监测。     

Influence of a high‐head dam as a dispersal barrier to fish community structure of the Upper Mississippi River

In river systems, high‐head dams may increase the distance‐decay of fish community similarity by creating nearly impermeable dispersal barriers to certain species from upstream reaches. Substantial evidence suggests that migratory species are impacted by dams, and most previous studies in stream/river networks have focused on small streams and headwaters. Here, we assess whether a high‐head dam (Lock and Dam 19; LD 19) on a large river, the Upper Mississippi River (UMR), substantially alters fish community structure relative to variability expected to occur independent of the dam's effect as a fish dispersal barrier. Using fish catch per unit effort data, we modelled the distance‐decay function for the UMR fish community and then estimated the similarity that would be expected to occur across LD19 and compared it with measured similarity. Measured similarity in the fish community above and below LD19 was close to the expected value based on the distance‐decay function, suggesting LD19 does not create an abrupt transition in the fish community. Although some migratory fish species no longer occur above LD19 (e.g., skipjack herring, Alosa chrysochloris), these species do not occur in high abundance below the dam and so do not drive variation in fish community structure. Instead, much of the variation in species structure is driven by the loss/gain of species across the latitudinal gradient. Lock and Dam 19 does not appear to be a clear transition point in the river's fish community, although it may function as a meaningful barrier for particular species (e.g., invasive species) and warrant future attention from a management perspective.     

Storm Water Harvesting in Saudi Arabia: a Multipurpose Water Management Alternative

This work evaluates the potential for rainwater harvesting at the household level in the dry climate of Saudi Arabia. The amounts of rainwater that can be harvested in several cities in Saudi Arabia were estimated and it was found that a significant volume, exceeding 7.5 m³/100 m² per year, can be harvested. The per cubic meter cost of harvesting rainwater was compared to that of producing desalinated water. It was found that harvested rainwater is cheaper to capture than desalinated water produced from renewable energy-driven desalination plants, but that is not the case for fossil fuel-powered desalination. The study also considered the effects of rainwater harvesting on mitigating floods and reducing greenhouse gas emissions. A cost-benefit analysis of installing rooftop rainwater harvesting systems in Saudi Arabia was performed. It revealed that it is economically feasible to harvest rain in cities including Hail, Jeddah, Taif, and Riyadh, while it is not recommended in the holy cities of Makkah, Medina, and Buraidah.     

Effect of selective water intake on the oxygen regime of a stratified reservoir

Conclusions