激光测距仪在水位测量中的应用

介绍了悬挂式水位测量装置的原理,并从浮子的设计、激光测距仪的安装、信号控制转换器、装置的可维护性等4个方面,分析了悬挂式水位测量装置的科学性,介绍了其在湖北清江水情自动测报系统中的应用情况,指出了悬挂式激光水位测量装置的技术优势和适用场合。     

常用水位传感器的比较和选择

总结常用的浮子式、压力式、超声波式、雷达式、激光式水位传感器的基本工作原理和主要优缺点,从设备的测量精度、测量量程、可靠性、所需配套土建、运行维护等方面对常用水位传感器进行相互比较,总结在实践中水位传感器选择的一些经验,提出水位传感器的选择应遵守可靠、精确、经济的先后原则。     

压力式水位传感器在水文自动测报系统应用中的精度分析

太湖流域水文自动测报系统中水位传感器，采用了加拿大克玛尔公司生产的压力式水位传感器，资料证明，该传感器室内率定时精度较高，但使用时，各水文测站所测水位精度不同，主要由于工作环境与室内有较大差异造成，论述了与人工水尺和综合式自记水位计的水位比例方法，分析了比例误差的原因，提出了设置压力式水位传感器的注意事项，列举了在太湖流域水文自动测报系统中的成功应用实例。     

吹气式水位计的改进设计

水电机组的现场测试是确定机组特性 ,实现最佳经济运行方式的重要手段 ,准确、可靠地测量水电站上下游水位以及集水井、拦污栅、船闸闸室等水位 ,从而了解水位是否在规定的范围 ,并使水位控制在允许范围内 ,对保证发电设备的安全经济运行具有十分重要的意义 ,水电站水位测量是机组现场测试的一个关键内容。吹气式水位测量装置主要由外部气源、气流控制器、压力 (差压 )变送器、吹气测量管组成。吹气式水位测量装置是一套小型测量系统 ,主要分为三大类 :水位测量装置ＩＰＳ系列、水位控制器ＢＬＣ系列、水位差测量装置ＢＤＣ系列。为满足三峡…     

水位和流量测量技术的最新发展

最近，在水资源管理领域内测量仪器已取得了一些新进展。现有有的测量系统能以小于０．０１％量程的精度记录压力，水流测量装置的精度为测量值的０．５％－１％，但是，仅有精确的测量系统还不足以取得准确的结果。本文结合几例讨论获取可靠的成果需要考虑的其它条件。     

浙江省水利防灾减灾重点实验室引进GDSTTS饱和土三轴仪、TAJ-2000大型动静三轴仪

浙江省水利防灾减灾重点实验室新引进1台25 kN高端Bishop&Wesley应力路径饱和土三轴仪系统,试样尺寸包含38,50,70,100 mm,最高承受2 MPa压力;围压和反压量程均为2 MPa,体积精度为测量值的0.1%(±30 mm3)。压力精度为     

实验室水位仪检测平台设计及应用

针对水利实验室水位仪技术指标的检测要求,研发了实验室水位仪检测平台。平台利用高精度传动及测量组件,能够快速检测常见实验室水位仪的精度、量程、采样周期及跟踪速度等技术指标。利用检测平台对探测式水位仪LH-1、探测式水位仪WEL-Ⅱ型、超声式水位仪进行了检测,检测结果表明这些水位仪的实际技术指标满足标称指标。     

斜井式激光水位测量装置

斜井式激光水位测量装置,为特殊条件下水位测量提供一种新的采集传输手段。介绍了斜井式水位装置的工作原理,并从浮子的设计、激光测距仪的安装、信号控制转换器、装置的可维护性等4个方面分析了实现斜井式水位测量的可用性,并通过实际应用,剖析了斜井式激光水位测量装置的技术优势和应用前景。目前＂斜井式激光水位测量装置＂已广泛用于水库、江河、湖泊等新建水位遥测站中,具有很好的推广价值。     

河流断面探入式精准测流装置的研发及应用

随着科技的进步和水利行业的快速发展,河流断面测流方式已逐渐由自动化代替人工测流,出现了多种自动化断面流量测量装置。测量装置按照测量方法可分成探入式和非探入式两种。提出了一种基于探入式测量方法,适用于多类型自动测量设备的通用型装置。该装置通过测量线长、偏角和倾角,结合采集处理技术,可精确测量河流断面水位、水深、淤积、分层流速等参数,适用于缆道型、轨道型等多种断面测流设备。通过实验检测及现场监测对比,结果表明采用该装置可大幅提高垂线测量精度。     

水电站单片机水位自动测量装置

介绍一种新型的潜入式液位传感器及以单片机为核心、可自动测量水电站水位的新型智能仪器。该测量装置只有测量准确、操作简便、上下限报警、自动记录打印或远距离传输测量数据的优点，可广泛用于测量水电站的水位。     

Understanding Seasonal Water Clarity Dynamics of Lake Dahuchi from In Situ and Remote Sensing Data

Obtaining, analyzing and understanding the seasonal dynamics of water clarity is of importance for understanding and managing lakes and sustaining their ecosystem services. This study aimed to explore the seasonal dynamics of water clarity and to analyze how water level, wind velocity and total precipitation influence this dynamics in Lake Dahuchi, China. The Secchi disk depths recorded in the field and derived from Moderate Resolution Imaging Spectroradiometer (MODIS) images together demonstrated a seasonal pattern of water clarity, which was lower in winter and spring, increased in April or May to reach the highest values in summer, upon which it gradually declined from September onward. Piecewise linear regression analysis between water clarity and water level showed that water level could explain 70% of the variation of the logarithm of Secchi disk depth. The water clarity of Lake Dahuchi was primarily controlled by suspended sediment, while the seasonal variation of water level induced different sediment resuspension, thus we concluded that the water clarity seasonal dynamics of Lake Dahuchi was mainly regulated by seasonal variation of water level.     

JS—B型精密水位仪的实验和使用

对JS—B型精密数字水位仪进行性能和技术指标的试验。通过半年来现场的使用试验,与JS—A型精密数字水位仪的对比试验,及计算机的联机试验,抗干扰、抗振动等性能试验,以及技术指标的测试试验等,认为仪器的主要技术指标均已达到了设计的要求。     

万寨寨水利枢纽分期汛限水位的研究

在对万家寨水利枢纽洪水特性进行分析的基础上,提出分期汛限水位,在保证枢纽度汛安全的前提下,求得对水资源的充分利用,以提高水利枢纽的经济效益和社会效益。     

近40年鄱阳湖水位变化趋势

利用实测水位资料,分析鄱阳湖水位近40年中的变化趋势,并用倾向率作定量描述。结果表明,鄱阳湖年最高水位以0.22m/10a的倾向率上升,其出现时间以3.2d/10a的倾向率推迟,大洪水年以0.06a/10a的倾向率增多,洪水位升高与大洪水增多使得洪涝灾害加剧,将成为鄱阳湖区开发整治中的突出问题。     

浅谈水位涨率法对单站洪水的预报

为了解决跨国界河流洪水预报问题,以广西平而水文站和水口水文站为例,采用以水位涨率为参数的相应水位法进行洪水预报。结果：洪水预见期,平而水文站为26h,水口水文站为13h,且预报精度均符合《水文情报预报规范》的要求。     

Enhancement of a global lake and reservoir database to aid climate studies and resource monitoring utilizing satellite radar altimetry

Here, we describe the expansion and enhancement of a large (surface area ≥100 km²) lake and reservoir database (1.GREALD). These efforts have also resulted in the spin-off of two additional databases, one containing lakes and reservoirs (2.GREALD, area 10–99 km²), and the other containing ephemeral lakes (3.GELD, area ≥100 km²). These databases are unique sources for projects that utilize satellite radar altimeter data to monitor surface water levels. While 1.GREALD aims to be a complete catalog, 2.GREALD focuses on reservoirs in response to applied sciences programs that monitor water and energy resources. The creation of 3.GELD has climate change objectives as well as water resources and ecosystem conservation applications. The recording of information pertaining to the potential overpasses (waterbody crossings) of the current and archive satellite altimeters is a primary objective as is the need to highlight any form of controlled water level variation. The permanent water databases now contain 6282 entries, half experience some form of anthropogenic influence and ～430 have been identified as potential climatically sensitive terminal lakes. The revised integral surface area distribution is a power law with exponent ?1.016. Statistics reveal that with altimetric repeat visit times of 10-day to monthly, at least 80% of the permanent water bodies (≥10 km²) have been overflown at some period since the 1990s. Current information on water use and reservoir formation date show that the primary use of the reservoir class is hydroelectric power, and that China, Brazil, India, Turkey, and Vietnam dominate the dam building in recent decades.     

The effect of Lake Erie water level variations on sediment resuspension

Variability in Lake Erie water levels results in variations of the fluid forces applied to the lake bed by free-surface gravity wind-waves. An increase in the bed stress may re-suspend sediment deposited years earlier. This study identifies areas of possible non-cohesive sediment mobilization in response to the forcing conditions and water levels present in Lake Erie. Observations from NOAA buoy 45005 were used to identify wave events generated by a variety of atmospheric forcing conditions. For each event, numerical predictions of significant wave height, wave period, and water level from the Great Lakes Forecasting System (GLFS) were used to characterize the wave event variability over the lake. The Shields parameter was estimated at each 2 km × 2 km grid cell with the local wave forcing as predicted by GLFS assuming an estimate of the wave-induced friction factor. In the Cleveland harbor region of the central basin, the Shields parameter was also estimated by assuming uniform wave conditions as observed by NOAA buoy 45005. The “contour of incipient motion” for both variable and uniform wave events was defined as the offshore contour where the Shields parameter exceeds the critical limit for motion. Comparisons with a radiometrically corrected image from Landsat-7 showed that the spatially varying wave events from GLFS were in qualitative agreement with the satellite observations. A sensitivity analysis of wave height, wave period, and grain size showed the contour of incipient motion to be the most sensitive to wave period. Calculations performed for record high and low water levels showed that the incipient motion of non-cohesive sediments in the relatively flat central basin to be the most sensitive to the historic hydrologic variability present in Lake Erie.     

受洪水涨落影响水位流量关系延长方法探讨

本文结合本站水位后移法和曼宁公式两种方法,以抚河李家渡站为例,探讨受洪水涨落测站如何开展水位～流量关系延长,得出以下结论：通过本站水位后移法试算,采用后移时段1.5h可实现李家渡高水绳套曲线单值化;利用曼宁公式延长单值化曲线,并通过水位后移反算,可实现受洪水涨落影响的水位～流量关系的延长;两种方法结合,可为受洪水涨落影响的测站开展巡测分析和测验成果检验提供借鉴。     

Monitoring water level and volume changes of lakes and reservoirs in the Yellow River Basin using ICESat-2 laser altimetry and Google Earth Engine

Monitoring the water level and volume changes of lakes and reservoirs is essential for deepening our understanding of the temporal and spatial dynamics of water resources in the Yellow River Basin, with a view to better utilizing and managing water resources. In recent years, there have been many studies on monitoring water level and volume changes in inland waters, but they were mainly focused on radar altimetry and the full waveform LiDAR ICESat, which was retired in 2010. Few studies based on the latest photon-counting LiDAR ICESat-2 have been reported. Compared with previous sensors, ICESat-2 has great advantages in footprint size, transmitting frequency, pulse number, etc, but its performance in monitoring water level and volume changes in inland waters has not been fully explored. Here we investigated the spatial distribution of water level and volume changes of 11 lakes and 8 reservoirs in the Yellow River Basin based on ICESat-2 and Google Earth Engine, and analyzed the factors affecting the measurement uncertainties. In-situ validation of lake level in Lake Qinghai indicates that the Root Mean Square Error (RMSE) of our result is only 7 cm after the reference coordinate system conversion. We found that the water level trend of the natural lake shows significant seasonal variations, while the water level trend of the reservoir shows a sharp rise and fall. In addition, precipitation plays a decisive role in the changes in natural lake levels and indirectly affects the artificial control of reservoirs’ water discharges. The uncertainty of water volume change monitoring is mainly affected by water level measurement uncertainty for lakes, while for reservoirs, that is affected by the combination of water level and area measurement uncertainties. The stability of lake level measurement increases with the increase in photon counts. The introduction of ICESat-2 ATL13 Significant Wave Height might lead larger standard deviation in water level measurement. According to the law of propagation of uncertainty, the uncertainty of the water volume change estimation by the combination of ICESat-2 and GEE is less than 9 %.     

Effects of dams and reservoirs on the hydrological characteristics of the lower drava river

During the last 20 years numerous water supply, hydroelectric and other large structures have been built along the Drava River and in its catchment area in Slovenia, Croatia, Hungary and Austria. Their construction has greatly influenced the water regime of the Drava River, especially during low water periods. The changes in the low flow regime along the stretch from Varazdin (285 km) to its confluence with the Danube (0 km) are examined. The analysis includes changes in the water levels, discharges and the amounts of suspended sediment and bed load. The intensity of changes, the time of their occurrence and their trends are examined.