Comprehensive security risk factor identification for small reservoirs with heterogeneous data based on grey relational analysis model

Identification of security risk factors for small reservoirs is the basis for implementation of early warning systems.The manner of identification of the factors for small reservoirs is of practical significance when data are incomplete.The existing grey relational models have some disadvantages in measuring the correlation between categorical data sequences.To this end,this paper introduces a new grey relational model to analyze heterogeneous data.In this study,a set of security risk factors for small reservoirs was first constructed based on theoretical analysis,and heterogeneous data of these factors were recorded as sequences.The sequences were regarded as random variables,and the information entropy and conditional entropy between sequences were measured to analyze the relational degree between risk factors.Then,a new grey relational analysis model for heterogeneous data was constructed,and a comprehensive security risk factor identification method was developed.A case study of small reservoirs in Guangxi Zhuang Autonomous Region in China shows that the model constructed in this study is applicable to security risk factor identification for small reservoirs with heterogeneous and sparse data.

Estimation of Small Reservoir Sedimentation in Semi-Arid Southern Zimbabwe

Small surface reservoirs play an important role of providing ready and convenient source of water for various uses in semi-arid areas which are characterized by erratic and low rainfall. Lack of current data on reservoir capacity loss due to sedimentation is one of the challenges to the sustainable management of surface reservoirs. The study investigated the capacity loss due to sedimentation from 2000-2012, and estimated the trap efficiency of the Mutangi reservoir which is located in semi-arid Chivi, Southern of Zimbabwe. Hydrographic surveys, grab sampling and water depth-capacity methods were used to determine the capacity of the dam as of 2012. To compute capacity loss from 2000 to 2012, the 2000 and 2012 dam capacities were compared whilst the trap efficiency of the reservoir was determined using a set of empirical models that relates trap efficiency to the capacity-watershed area ratio and capacity-inflow ratio. The results show that Mutangi reservoir has a trap efficiency of 95% - 98% (av = 96.4%) and has lost 37% of its capacity due to sedimentation in 12 years (2000 and 2012). Rates of sedimentation were 8539 t·yr-1, 9110?t·yr-1 and 8265 t·yr-1 for the hydrographic survey, grab sampling and water depth-capacity method respectively, and the little difference in these figures demonstrates that any method can be used to determine sedimentation rates. The area specific sediment yield (ASY) ranged from 14 - 15.5 t·ha-1·yr-1 (av = 14.956 t·ha-1·yr-1). At the current rate of sedimentation the projected dead level of the reservoir will be lost to sedimentation in 8 years while the useful life of the reservoir is estimated to be 30 years. Capacity loss due to sedimentation is further complicating the already strained water scarcity situation in semi-arid areas and management decisions should be made based on the current sedimentation rates estimated by different methods. These results imply that management practices that reduce erosion, hence sedimentation in these small reservoirs should be practiced in order to prolong their lifespan.

Assessment of Sedimentation Impacts on Small Dams—A Case of Small Reservoirs in the Lotsane Catchment

Sedimentation is a major problem for agricultural dams in Botswana, as it reduces the storage capacity and life span of the reservoirs. The process of sedimentation starts from day one of the impounding of water in any given reservoir. Even though a provision is made for every reservoir during planning for a certain storage capacity, specifically for sediment deposition, called dead storage, a major portion of the sediment gets deposited for many years of the reservoir’s life in areas other than the dead storage, and this trend cannot be reversed at easy cost. This study is aimed at the analysis of prevailing sedimentation processes in the nearby dozens of dams found in the Lotsane catchment located within the Limpopo Basin of Botswana, and focuses on assessment of annual sedimentation rate. A spatial analysis and modelling study was conducted based on the Revised Universal Soil Loss Equation and GIS to determine sediment yield and degree of impact of each reservoir for a given landscape, rainfall and catchment heterogeneity. Field observations and soil sampling were carried out in order to determine the factors that lead to reservoir sedimentation. Spatial data on the dams in Lotsane catchment were also collected from Ministry of Agriculture, which were used for ground-truthing, GIS-based calculations and model validation. The average sediment rate and sediment delivery ratio were found to be 1.74 t/ha/year and 81%, respectively. These are useful parameters to estimate service life of the dams and plan remedial measures related to sedimentation problems.

Research and application of flood detention modeling for ponds and small reservoirs based on remote sensing data

This paper proposes a method of small reservoir flood detention modeling that utilizes data from the American land resources satellite Landsat TM/ETM+. Precipitation and potential evapotranspiration are taken as the control conditions in this method on the basis of basin terrain classification. The objective of this method is to solve the question of a small-scale water conservancy project’s influence on flood forecasting precision, which can be used in the basin with multitudinous small reservoirs in the upstream region and can help estimate non-runoff data for small reservoir runoff. Taking the 20060826 flood as an example, the flood detention quantity of 19 small reservoirs is modeled. The results show that the absolute error of the total flood detention quantity is 0.2×10 4 m 3 , and the relative error is 0.12%. The flood detention quantity of small reservoirs in the entire basin is then modeled using this method, and the primary flood forecasting model is adjusted. After adjustment, the precision is significantly improved, with the relative error decreasing from 31.8% to 10.1%.

小型水库预报预警系统研发与应用

针对小型水库洪水预报预警研究不足问题,以构建的分布式水文模型、缺资料地区参数移植技术,以及小型水库防洪预警方式与指标体系、预警方案编制等为支撑,利用Java语言、Vue技术、ElementUI组件、EChart组件、Spring Boot、JSON数据交互等技术,设计开发了一套基于B/S架构的标准化、通用型小型水库预报预警系统。介绍了系统的设计模式及功能结构,阐述了基础信息展示、洪水预报、防洪调度、洪水预警、数据管理、基础空间地理分析等主要系统模块的设计,以及系统开发关键技术。以在安徽省的应用为例,展示了系统具备的可靠性、灵活性与实用性。

Impact of the Small Town Construction on Original Inhabitants in the Three Gorges Reservoir Area——A Case Study in Lishu Village, Changling Town, Chongqing Municipality, China

Based on the five-year long dynamic tracking and investigation of the peasant households of the Lishu village, the influences by small town construction on the economy and employment of the original peasant households are discussed. On the one hand, small town construction plays a positive role in adjustment of the industrial structure of the original peasant households and in the transfer of their employment towards non-agricultural industries. On the other hand the economic growth of the original peasant households is not so well sustainable, and is so fluctuating. Moreover, the unbalance of income distribution of the said households has been furthered, and small town construction has made the existing labor surplus of the original peasant households more serious, particularly the women labor surplus.

The Influence of Land Use and Fish Farming on the Contents of Ca²⁺, Mg²⁺, K⁺and Na⁺in Pond and Reservoir Ecosystems in an Agricultural Small Watershed, China

It is not understood well that how the effects of land use and fish farming on the contents of alkali metals (Ca2+, Mg2+, K+ and Na+) in small water bodies of pond and reservoir ecosystems at the watershed scale. In this study, the concentrations of Ca2+, Mg2+, K+ and Na+ in water bodies were measured for 103 ponds and reservoirs used as fish farming or surrounded by different agricultural land use types in the subtropical hilly watershed of Jinjing (105 km2), China. The two important environmental factors of fishing farming and agricultural land use influenced the spatial variation the contents of alkali metals. The ponds and reservoirs in residential area had significantly higher concentrations of Ca2+ and Na+ than those with other land use types, reflecting the influence of domestic wastewater. Compared with those of natural ponds with non-fish farming, no significant increase of alkali metal contents occurred in fish farming ponds, due to the regular cleaning of ponds by farmers. However, the effect of fish culture on alkali metal contents was still supported indirectly by the fact that the alkali metal contents significantly correlated with nitrate contents in fish farming ponds and but high related with that of DIP in natural ponds. The suitability assessment for irrigation on the pond water indicated that almost all of ponds were suitable for irrigation except some ponds surrounded by residential area and tea plantation. Generally, our results demonstrated that fish farming and agricultural land use affected the contents of alkali metals in ponds and reservoirs. The agricultural water irrigation would be with caution from the ponds with tea plantation and residential area in the subtropical hilly watershed.

华庆油田H201延8油藏小层划分方案及地质意义

在充分吸收前人对H201延8油藏的地质认识的基础上,结合新、老井资料对研究区标志层及各小层电性响应、岩性组合、沉积旋回特征进行深入研究,基于以上研究成果将研究区内的延8地层重新划分为延81、延82、延83三个小层,利用划分结果绘制地层剖面及构造图,对地层厚度及平面展布特征进行了研究。其中,延8地层整体厚度介于27~42m之间,各小层间厚度相差不大,平面上整体呈现东高西低的趋势,北部较南部坡降大,内部发育局部微构造高点。

新形势下提升小型水库除险加固工程竣工验收水平的对策分析

对小型水库除险加固常态化的新形势,结合攻坚行动的现场核查情况,分析总结历次规划(方案)中未及时竣工验收的小型水库除险加固项目存在的问题,并结合新形势下小型水库除险加固面临的新要求,提出了提高小型水库除险加固工程竣工验收效率和质量的对策与建议,可为小型水库除险加固工程的竣工验收管理提借鉴。

基于Django的小水库雨水工情一体化监测平台研究与开发

文章基于Django的开发框架,研究开发了小型水库雨水工情一体化监测信息管理平台,解决了平台开发过程中Web应用扩展开发困难、表单处理能力不足、数据库开发要求较高等问题,可实现小型水库雨量、水位、大坝渗压自动监测和信息综合展示功能。工程数据试验表明,该平台可靠、可高速运行。

山东省小型水库专业化管护模式实践研究

小型水库专业化管护是破解小型水库安全难题的重要举措,随着小型水库管理体制改革不断深化,各地探索实行的管护模式具有相似性,也表现出区域差异性。以山东省小型水库管护模式建设为例,在梳理山东省基层管护现状、管护模式分类和管护模式组织机构基础上,选取16个典型县区进行管护模式实践成效分析,总结得到不同管护模式的适应条件与建设要点。从管护模式推行、工程基础、管护企业培育、巡库员队伍建设、智慧化管护等方面提出了小型水库专业化管护模式长效运行相关建议。

小型水库洪水预报模型研究及应用

针对缺资料地区小型水库入库洪水预报难的问题,构建了一种小型水库入库洪水预报模型,其产流模块采用SCS模型,汇流模块采用地貌瞬时单位线,模型参数基于高精度地形地貌数据确定,不依赖于实测流量资料进行模型参数率定,并在安徽省永堌水库进行了应用。采用1818号台风“温比亚”期间永堌水库强降雨洪水进行了验证分析,应用结果表明,构建的模型对该场次洪水过程两次洪峰模拟值与专家反推的入库洪峰较为一致,相对误差分别为3.2%和-11.8%,均在±20%以内,峰现时差均为0,径流深模拟相对误差为-19.2%,确定性系数为0.949,说明建立的小型水库入库洪水预报模型对本次降雨洪水模拟效果较好,对其他小型水库入库洪水预报具有较好的参考和借鉴意义。

小型水库库容精确测算方法研究

我国小型水库数量众多,是调控水资源分配的重要基础设施。为了精确测量水库周边地形以及计算库容,本文提供了一套完整的测算方法。首先,采用机载摄影测量与激光雷达采集库岸数据,用无人船采集水下地形数据。然后,进行数据处理并提出了一种三角网精确分割库容计算算法。该方法对测量点云数据建立三角网,并对三角网中每一个三角形进行判断,通过对三角形中每一个点的高程与水平面高程进行对比,分为一点小于水平面高程、两点小于水平面高程、三点小于水平面高程3种类型,分别计算体积并进行累加获得不同高程值的库容量。最后,基于C++开发了库容精确计算程序。将本文算法与等高线法计算的库容进行对比,两者的误差小于2%,且其中多数小于1%。本文研究可为小型水库库容的精确测算提供技术支持。

广东省降等报废小型水库周边土地利用变化特征分析

以广东省2020—2022年实施降等或报废的小型水库作为研究对象,引入单一土地利用空间动态度、综合动态度和变化强度等指标,对2000—2020年期间水库周边土地利用之间的相互动态转化和时空变化特征进行分时段统计分析。研究结果表明:①2020—2022年广东省实施降等或报废的小型水库周边土地利用变化主要发生于2010—2020年,以耕地、森林和草地向人造地表的转化为重要特征,其中耕地向人造地表的转化最为突出;②耕地面积萎缩和人造地表扩张是广东省小型水库实施降等或报废的重要驱动因素;③此类驱动性转变最先发生于珠三角地区,在粤北地区表现最为显著。

农业小流域句容水库出入库水体CO_(2)、CH_(4)浓度与通量特征

为探究农业小流域句容水库出入库水体二氧化碳(CO_(2))、甲烷(CH_(4))的变化特征,本研究以句容水库为研究对象,进行为期2年的逐月野外试验,探明农业小流域水库水体CO_(2)、CH_(4)浓度与通量特征。结果表明:句容水库出入库水体CO_(2)、CH_(4)浓度和排放通量存在明显的空间差异。就年均CO_(2)浓度和排放通量而言,入库口A〔(108.57±14.27)μmol·L^(-1)、(210.55±36.58)mmol·m^(-2)·d^(-1)〕和入库口B〔(162.74±17.86)μmol·L^(-1)、(338.74±47.25)mmol·m^(-2)·d^(-1)〕显著高于出库口〔(28.04±3.53)μmol·L^(-1)、(10.05±4.04)mmol·m^(-2)·d^(-1)〕;入库口B年均CH_(4)浓度和排放通量〔(747.05±190.63)nmol·L^(-1)、(1.84±0.46)mmol·m^(-2)·d^(-1)〕显著高于出库口〔(115.75±15.75)nmol·L^(-1)、(0.11±0.02)mmol·m^(-2)·d^(-1)〕。句容水库水体CO_(2)、CH_(4)浓度和排放通量有明显的季节变化,水体CO_(2)、CH_(4)浓度和排放通量均表现为暖季高、冷季低的变化规律,其水体CO_(2)、CH_(4)浓度和排放通量的时间变化显著受到水温、溶解氧浓度和降水量的影响,同时外源氮素的输入影响CO_(2)、CH_(4)浓度和排放通量的空间变化。综上,农业小流域句容水库是大气CO_(2)、CH_(4)的排放源,排放通量高于国内水库平均值。

效益风险综合评价模型在论证小型水库降等报废中的应用——以广东省小型水库为例

针对小型水库降等报废论证中关于成本、效益及可能的失事风险难以量化的问题,提出了一种效益风险综合评价模型,结合工程实际资料,选取并测算了成本、效益及可能的失事风险三方面共9个指标,计算得到了评价指标θ,其值对应了不同的处置建议,研究成果可为小型水库降等报废的论证工作提供参考。

广东雨窝地形下中小水库极端降水及其发生时间的特征分析

广东清新—佛冈—龙门是广东三大暴雨中心之一,历史上曾多次发生洪涝灾害,大秦、银盏、良洞和黄龙带四座中小水库地处该雨窝中心,因而提升其防洪减灾及水资源管理能力亟待研究。利用研究区域内93个站点的历史逐日雨量数据,基于EEMD分解、圆形统计和R/S分析等方法,对这四座中小水库的极端降水及其发生时间的特征进行分析。结果表明,四座水库各极端降水指数主要表现为准3、7年的年际变化周期;四座水库的极端降水主要发生在前汛期,且未来发生时间仍会高度集中;良洞水库具有最强的降水强度和极值降水,大秦和银盏水库的降水极端性在未来有增强趋势,应特别关注;在年初的冬季至秋季需做好四座水库灾害性天气的监测和预警,其中春夏季需重点关注良洞水库极端降水的发生。

加强小型水库运行管理的思考与建议

以小型水库运行管理为例,提出了当前小型水库存在的问题,分析了小型水库运行管理面临的形势,结合实际提出了加强小型水库运行管理工作的相关建议,可为小型水库运行管理工作提档升级提供参考与借鉴。

小型水库除险加固防渗提升技术应用研究

水利工程除险加固对于水库的长期安全运行至关重要,水磨坑水库建成年代早,影响水库安全稳定的工程地质条件复杂,同时坝体存在渗流安全稳定隐患,亟需提升大坝防渗能力。以水磨坑水库为研究背景,从混凝土防渗墙、坝基帷幕灌浆和重设排水棱体等多方面,针对大坝渗流和安全稳定进行加固优化提升,并进行复核分析,提出合理的变形渗流监测补充措施。

小型水库除险加固工程主要水工建筑的安全与设计研究

某小型水库存在渗流稳定,溢洪道不满足泄洪要求的问题,这些安全隐患严重影响水库的安全稳定运行。以某小型水库为研究对象,在其除险加固工程的过程当中,对大坝坝体和溢洪道进行安全复核和加固设计,通过比对相应的除险加固方案,最终发现采用充填灌浆,重建溢洪道消力池等方案处理小型水库的病险问题具有良好效果。