Development and implementation of domestic suction dredges with submersible pumps

One of the main directions in upgrading suction dredges is equipping them with submersible dredge pumps. __________ Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 9, September 2006, pp. 5–10.     

Removal of organic sediments from reservoirs and lakes and their processing

The experimental-industrial cleaning of Latvian lakes and the removal of sapropel at its in situ moisture content by a suction-tube dredge with a chambered pneumatic pump made by the Italian firm Pneuma, and also a new procedure for production of commercial sapropel are described.     

Use of hydraulic excavation for cleaning and construction of water bodies

The materials in this paper are based on practical work performed by the establishment JSC “Sapropel’” in cleaning water bodies sand small rivers in Nizhnii Novgorod and the Nizhegorodskaya Oblast. For this purpose, the establishment has developed and built small dredges with a water output of 400 – 1600 m³/h. Using these dredges, significant volumes of water bodies can be cleared of silt deposits in order to return them to their normal ecological state for water management. An algorithm for selection of the type of dredge as a function of the volume to be cleared, the time required for the work, and characteristic features of the soils has been developed based on analysis of the work performed.     

Output of suction dredges with respect to solids

Conclusions Quite brief operation of the suction dredge and its pipeline on clear water permits determining the minimum value of the head being developed by a given dredge, and all subsequent heads during its operation with mixtures permit, with consideration of other factors (as indicated), determining the amount of solids being transported by water through the pipeline at a given time and during any time period in tons or cubic meters.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 10, pp. 45–47, October, 1992.     

挖泥船增加水下泥泵技术经济分析

为了提高目前国内使用挖泥船的综合效益,在原有挖泥船基础上增加水下泥泵,可以用较少的投资大幅度提高经济效益,减少单位土方的能量消耗,为国家节能环保做出贡献。     

Minor local effects of a River Thames power station on the macroinvertebrate fauna

In July 1996, a survey of the macroinvertebrate fauna of the River Thames was undertaken in the vicinity of Didcot A Power Station, which is located on the right (south) bank of the river. The aim was to determine whether short‐range biological effects could be detected due to abstraction and discharge of cooling water. Sampling zones were selected upstream of the abstraction point (zone A), between the abstraction and discharge point (zone B), and below the discharge point (zone C). Five pond‐net and five dredge sampling units were taken from each bank in each of zones A, B and C and analyses were undertaken at BMWP family level. A total of 46 BMWP families were captured during the survey. Marginal pond‐net samples from the left bank had a significantly higher mean number of BMWP taxa than those from the right bank. These differences are thought to be due to the greater diversity of macrophytes and substrata on the left bank. In addition, there were lower numbers of BMWP taxa on the right bank of zone C compared with zone B (but not zone A), probably due to poor quality habitat. When the fauna from dredge samples in ‘control’ zone A was compared with zone B, there was no evidence on either bank of a deleterious impact on the fauna in zone B. Comparison of dredge samples from zone C with those from zones A and B, revealed no statistically significant differences in the number of BMWP taxa between zones C and A or between C and B on either bank. However, the first two dredge sampling units from the right bank of zone C, immediately downstream of the discharge point, had just five and 12 BMWP taxa, respectively, compared with a range of 17–28 taxa in all other dredge samples (on either bank of the three zones). These results correlated with a local change in dominant substratum to sand and associated fine particles, and suggest a very localized effect of the discharge on river‐bed morphology and hence on the fauna of the right bank in zone C. Copyright © 2000 John Wiley & Sons, Ltd.     

The 200-50R demountable suction dredge

Conclusions The analysis of results of operation and exhaustive tests of the new 200-50R demountable suction dredge demonstrated the efficiency and reliability of the adopted design and permitted recommending the mass production of this machine. Mass production of the 200-50R suction dredge started in 1979.Addition of demountable machines to the existing suction dredging equipment will make it possible to substantially expand the field of application of hydromechanization, and will undoubtedly constitute an appreciable factor in the raising of the earthwork mechanization level.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 9, pp. 12–15, September, 1980.     

Improvement of measuring devices for monitoring dredge operation

Conclusions  

河道采砂管理船载监控终端研发

为加强对持证采砂船只采砂活动的监管,提出一款成本适中、功能实用、安装于持证采砂船只上的船载监控终端,该装置支持定点、定时、定功率开采监控及采砂量无线远传功能,可对采砂过程实施有效监视、控制。该船载监控终端支持数据存储转发功能,保证了无线通信的可靠性。监控终端采用的低功耗设计策略,提高了装置硬件平台的可靠性。     

黄河河口拦门沙疏浚综合技术的探讨

黄河河口拦门沙是河海动力相互作用后径流势能锐减,咸淡水混合,泥沙絮凝加速沉积而成的堆积体,是造成河口河段泄水泄沙不畅、淤积加快、水位抬高和流路摆动的重要因素。通过对以往黄河口口门5种疏浚技术方案的综合分析比选,推荐绞吸式挖泥船和扰沙船两种技术方式相结合进行疏浚黄河口拦门沙。     

盐龙湖表面流人工湿地底泥氧化层对污染物释放的影响

为了解盐城市盐龙湖表面流人工湿地底泥氧化层理化性质,探讨其对底泥氮、磷及有机物释放过程的影响,在测定底泥理化性质的基础上进行了室内静态柱状试验。结果表明:盐龙湖表面流人工湿地长期运行后在底泥表层形成了厚度为1 cm、呈棕黄色、无明显臭味、含水率低、TP含量高、TOC和TN含量低的氧化层;氧化层对于底泥中污染物的释放特征影响显著(P0.05),对内源污染的控制具有一定的正面作用;无氧化层试验组上覆水中TN、NH_3-N和COD的平均质量浓度分别比有氧化层试验组高9.5%、30.8%和3.5%;在湿地的实际管理中,不宜对湿地进行疏浚,如疏浚则疏浚深度应达到健康层。     

Climate Variability Influences on Hydrological Responses of a Large Himalayan Basin

The hydrological cycle, a fundamental component of climate is likely to be altered in important ways due to climate change. In this study, the historical daily runoff has been simulated for the Chenab River basin up to Salal gauging site using a simple conceptual snowmelt model (SNOWMOD). The model has been used to study the impact of plausible hypothetical scenarios of temperature and rainfall on the melt characteristics and daily runoff of the Chenab River basin. The average value of increase in snowmelt runoff for T + 1°C, T + 2°C and T + 3°C scenarios are obtained to be 10, 28 and 43%, respectively. Whereas, the average value of increase in total streamflow runoff for T + 1°C, T + 2°C and T + 3°C are obtained to be 7, 19 and 28%, respectively. Changes in rainfall by −10 and + 10% vary the average annual snowmelt runoff over the T + 2°C scenario by −1% and + 1% only. The result shows that melt is much more sensitive to increase in temperature than to rainfall.     

Utilization of Time-Based Meteorological Droughts to Investigate Occurrence of Streamflow Droughts

Complexities of streamflow drought analyses motivate utilization of simple, alternative methods, which can provide timely information for effective water resources management. For this purpose time-based meteorological drought characteristics, identified by SPI _{3 − month} , SPI _{6 − month} and SPI _Anuual are investigated. A boxplot approach is used to exclude non-rainy months from the analysis. Streamflow drought characteristics are described by drought intensities, and are calculated by the threshold level method. The non-parametric Wilcoxon–Mann–Whitney test is used to investigate relations between streamflow drought intensities and SPI _{3 − month} , SPI _{6 − month} and SPI _Anuual . The study area is the Doroodzan Watershed and Reservoir in southwestern Iran, with four rain gauge and two hydrometric stations. According to the results, most of time-based SPI values show significant relations (at 5% level of significance) with streamflow drought intensities. However, the most significant relation is between SPI _Anuual of Jamalbeik rain gauge station (centrally located in the study area) and drought intensities of Chamriz hydrometric station (located at the reservoir inlet). Comparison of study results with available records of documented droughts, confirms applicability of the proposed procedures. The SPI _Anuual is based on one-year-ahead moving average rainfalls. Then, SPI _Anuual of Jamalbeik station can be used to investigate occurrence of streamflow drought in Chamriz hydrometric station.     

Comparability Analyses of the <Emphasis Type="Italic">SPI</Emphasis> and <Emphasis Type="Italic">RDI</Emphasis> Meteorological Drought Indices in Different Climatic Zones

Comparability analyses are performed to investigate similarities/differences of the standard precipitation index (SPI) and the reconnaissance drought index (RDI), respectively, utilizing precipitation and ratio of precipitation over potential evapotranspiration (ET ₀). Data are from stations with different climatic conditions in Iran. Drought characteristics of the 3-month, 6-month and annual SPI and RDI time series are developed and Markov chain order dependencies are investigated by the Log-likelihood, AIC and BIC tests. Steady state probabilities and Markov chain characteristics, i.e., expected residence time in different drought classes and time to reach “Near Normal” class are investigated. According to results, both indices exhibit an overall similar behaviour; particularly, they follow the first order Markov chain dependency. However, climatic variability may produce some differences. In several cases, the “Extremely Dry” class has received a more critical value by RDI. Furthermore, the expected residence time of “Near Normal” class and expected time to reach “Near Normal” class are quite different in a number of cases. The results show that the RDI by utilizing the ET ₀ can be very sensitive to climatic variability. This is rather important, since if the drought analyses are for agricultural applications, utilization of the RDI would seem to serve a better purpose.     

Design of hydraulic-fill dumps and environmental protection

Conclusion Hydraulic-fill dumps must be designed with minimum appropriation of land areas with the construction of large borrow pits in the base. To prevent seepage of water into groundwaters, it is necessary to construct a watertight facing in the base of the dump and particularly in the pit by one of the following methods: striplike placement of soil on ice; delivery of the mixture into the pit with excavation of the soil in piles by a monitor; excavation of the pit by a dredge and hydraulic filling of narrow-profile embankments.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 2, pp. 46–48, February, 1992.     

Adaptation to Climate Change in the Management of a Canadian Water-Resources System Exploited for Hydropower

The management adaptation potential of the Peribonka River water resource system (Quebec, Canada) is investigated in the context of the evolution of climate change. The objective of this study is to evaluate the impacts on hydropower, power plant efficiency, unproductive spills and reservoir reliability due to changes in the hydrological regimes. The climate change projections used here are from the Canadian regional climate model (CRCM) nested by the Canadian-coupled global climate model (CGCM3) forced with the SRES A2 greenhouse gas emission scenario. The hydrological regimes were simulated with the distributed hydrological model Hydrotel. They were incorporated into a dynamic and stochastic optimization model in order to adapt the operating rules of the water resource system annually, according to the evolution of the climate. The impacts were analyzed over the years 1961–2099, split into four periods for comparison purposes: control period (1961–1990), horizon 2020 (2010–2039), horizon 2050 (2040–2069) and horizon 2080 (2070–2099). The main results indicate that annual mean hydropower would decrease by 1.8% for the period 2010–2039 and then increase by 9.3% and 18.3% during the periods 2040–2069 and 2070–2099, respectively. The trend to increase is statistically significant starting from 2061 (Mann–Kendall with p = 5%). The change in the mean annual production is statistically significant for the 2040–2069 and 2070–2099 periods (t-test with p = 5%). Also, the change in the variance is significant for the periods 2010–2039, 2040–2069 and 2070–2099 (F-test). Annual mean unproductive spills would increase from 1961–2099, but the trend is not statistically significant. However, the changes in the variance of the annual mean spills are significant in the periods 2010–2039, 2040–2069 and 2070–2099. Overall, the reliability of a reservoir would decrease and the vulnerability increase as the climate changes.     

Hantush’s M(α, β) and M*(α, β) are Generalized Incomplete Exponential Functions

It is pointed out that Hantush’s M(α, β) and M*(α, β) functions, two functions that arise with respect to groundwater pumping modeling, are particular cases of the generalized incomplete exponential functions known in the mathematics/statistics literature. Some relevant computational issues are discussed.     

Nomograms for preliminary design of pressure tunnel linings

Conclusions By means of the proposed nomograms it is possible to select at preliminary stages of design the economically advantageous types and dimensions of linings of tunnels being driven in isotropic rocks. From an examination of the solutions obtained from the nomograms, we can draw the following conclusions, which have also been included in the “Instructions on the Designing of Hydraulic Tunnels,” namely: a) it is recommended to use concrete linings in tunnels with an inside diameter up to 6 m in rocks withf _st=2–10 at internal water pressure heads not exceeding 20–90 m, respectively; here it is recommended to take into account the economy of labor expenditures in comparison with other types of linings; b) reinforced-concrete linings should be used: in weak rocks (f _st=0.5–1.0) at internal water heads to 40 m and in stronger rocks (f _st≥2) for tunnels with D_i=5 and greater at heads to 50 m, and in strong rocks (f _st=15) to 140 m; c) two-layer linings with an inner reinforced-gunite ring up to 15 cm thick should be used at heads of 50 m and greater in rock of medium strength and higher (f _st≥3); d) two-layer linings with an inner steel shell should be used in granular and soft rocks (f _st=0.5–1.0) with D_i≥10 m, and also at neads of 40 m and greater for any tunnel sections in these rocks and in cases of the economic inexpediency or structural impossibility of using other types of linings. Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 4, pp. 15–19, April, 1973.     

First Record of Corophium mucronatum Sars (Crustacea: Amphipoda) in the Great Lakes

Corophium mucronatum Sars, a small amphipod native to the Caspian and Black Sea basins, was discovered in September 1997 in Lake St. Clair. A single individual was collected using a bottom sled dredge in littoral waters adjacent to Seaway Island, Ontario. The specimen was found on silty-sand substrate in an area populated by submerged macrophytes. Because no other Corophium individuals were found despite repeated sampling over two years at a total of 60 sites in the corridor between the St. Clair River and western Lake Erie, it is highly unlikely that this species has established in the Great Lakes.