长江上游高洪水期泥沙输移特性

长江上游高洪水期(汛期)泥沙输移特性是决定三峡库区泥沙淤积的关键因素,直接关乎三峡水库使用寿命及综合效益的发挥。借助干、支流长系列水沙资料,分析了长江三峡水库入库寸滩站高洪水期泥沙输移特性,结果表明:近40 a来,寸滩站场次洪水中7 d洪量未出现趋势性变化,而7 d沙量显著减少,高洪水期输沙经历了“涨水输沙占优—涨、落水基本持平—落水输沙占优”的变化过程。2013年以前,寸滩站高洪水期径流及泥沙均主要来自于金沙江,而向家坝、溪洛渡水电站陆续投运后,2013—2019年寸滩站洪水场次(洪峰流量30 000 m³/s以上)共计14场。从径流来源来看,仅4场主要来自于金沙江,其余9场主要来自于嘉陵江,1场来自岷江;从泥沙来源来看,9场主要来自于嘉陵江,其余5场分别来自于沱江、岷江、横江,金沙江已不是寸滩站高洪水期过程中泥沙的主要来源区。研究成果可为三峡水库沙峰排沙调度、库尾减淤调度提供理论支撑,为长江泥沙治理提供保障。     

Effects of extreme floods on macroinvertebrate assemblages in tributaries to the Mohawk River,New York,USA

Climate change is forecast to bring more frequent and intense precipitation to New York which has motivated research into the effects of floods on stream ecosystems. Macroinvertebrate assemblages were sampled at 13 sites in the Mohawk River basin during August 2011, and again in October 2011, following historic floods caused by remnants of Hurricane Irene and Tropical Storm Lee. The annual exceedance probabilities of floods at regional flow‐monitoring sites ranged from 0.5 to 0.001. Data from the first 2 surveys, and from additional surveys done during July and October 2014, were assessed to characterize the severity of flood impacts, effect of seasonality, and recovery. Indices of total taxa richness; Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness; Hilsenhoff's biotic index; per cent model affinity; and nutrient biotic index‐phosphorus were combined to calculate New York State Biological Assessment Profile scores. Analysis of variance tests were used to determine if the Biological Assessment Profile, its component metrics, relative abundance, and diversity differed significantly (p ≤ .05) among the four surveys. Only total taxa richness and Shannon–Wiener diversity increased significantly, and abundance decreased significantly, following the floods. No metrics differed significantly between the July and August 2014 surveys which indicates that the differences denoted between the August and October 2011 surveys were caused by the floods. Changes in taxa richness, EPT richness, and diversity were significantly correlated with flood annual exceedance probabilities. This study increased our understanding of the resistance and resilience of benthic macroinvertebrate communities by showing that their assemblages were relatively impervious to extreme floods across the region.     

1959-2018年山东省降水时空分布特征与洪旱演变规律

基于山东省1959-2018年地面气象观测站逐日降水资料,应用反距离权重插值、Z指数、Mann-Kendall检验及小波分析等研究方法,探讨近60年来山东省降水的时空分布特征及洪旱演变规律。结果表明：空间分布上,降水量存在显著的地区差异,呈现东部多西部少且山区多于平原的空间分布格局。时间分布上,多年平均降水量呈现下降的变化趋势,东部沿海地区下降速率比西北内陆地区快。山东省的洪旱灾害具有年代际变化特征,20世纪70年代前,涝灾频繁,80年代到21世纪初旱灾频繁,21世纪后,主要发生偏涝,洪旱灾害地区间差异明显。研究结果对该省防灾减灾及区域经济发展具有重要意义。     

Do Management Actions to Restore Rare Habitat Benefit Native Fish Conservation? Distribution of Juvenile Native Fish Among Shoreline Habitats of the Colorado River

Many management actions in aquatic ecosystems are directed at restoring or improving specific habitats to benefit fish populations. In the Grand Canyon reach of the Colorado River, experimental flow operations as part of the Glen Canyon Dam Adaptive Management Program have been designed to restore sandbars and associated backwater habitats. Backwaters can have warmer water temperatures than other habitats, and native fish, including the federally endangered humpback chub Gila cypha, are frequently observed in backwaters, leading to a common perception that this habitat is critical for juvenile native fish conservation. However, it is unknown how fish densities in backwaters compare with that in other habitats or what proportion of juvenile fish populations reside in backwaters. Here, we develop and fit multi‐species hierarchical models to estimate habitat‐specific abundances and densities of juvenile humpback chub, bluehead sucker Catostomus discobolus, flannelmouth sucker Catostomus latipinnis and speckled dace Rhinichthys osculus in a portion of the Colorado River. Densities of all four native fish were greatest in backwater habitats in 2009 and 2010. However, backwaters are rare and ephemeral habitats, so they contain only a small portion of the overall population. For example, the total abundance of juvenile humpback chub in this study was much higher in talus than in backwater habitats. Moreover, when we extrapolated relative densities based on estimates of backwater prevalence directly after a controlled flood, the majority of juvenile humpback chub were still found outside of backwaters. This suggests that the role of controlled floods in influencing native fish population trends may be limited in this section of the Colorado River. Copyright © 2014 John Wiley & Sons, Ltd.     

南渡江左岸排涝工程研究

南渡江下游左岸是洪涝灾害十分频繁的洪泛区,一般年份洪水即可入侵农田和村庄,对农业生产造成极大损失.如遇20年一遇洪水,项目区积水深度会超过1 m左右,持续时间达2～3d,为排出防护区内涝水,设计应用ArcGIS分析地形并划分排涝分区,通过调蓄计算确定排涝工程规模.     

Groundwater quality monitoring overview

A study was made to develop an approach to designing a groundwater-quality network for implementation by Mexico's Comisión Nacional del Agua (CNA) under support funding from The World Bank's (1996) PROMMA program. The network-design conceptualization and guidelines were based in part upon review of CNA's past and existing monitoring programs in measurement of water levels as well as measurements and analyses of groundwater quality. The principal focus used for this network-design framework rather was derived from identification of specific monitoring-program information needs. Also, a detailed review has been made of available reports and technical materials describing the nature, extent, and management of Mexico's groundwater resources and groundwater-quality impacts. This physical-based approach complemented a socioeconomic-based methodology being developed concurrently. Specific selection criteria and recommendations were made regarding network design components, in terms of monitoring locations, scheduling, and variables (parameters). Understandably, this preliminary design methodology, when implemented, should take into consideration somewhat realistic levels of effort that are judged to be fiscally sustainable by CNA over the near term. Moreover, some guidance also is provided in the case of fiscal or capacity-building limits of monitoring-program efforts.     

Calendar of Future Meetings Involving IWRA

ABSTRACT

Irrigation-water-delivery systems are designed and managed to receive water from a source and to distribute it among farmers in order to meet their agricultural requirements. High system performance can be achieved through rehabilitation of deteriorating and inadequate physical facilities and through improved system management. Various design decisions must be made in order to rehabilitate or develop irrigation-water-delivery systems, including those related to specification of the characteristics of hydraulic structures used to convey regulate, or divert water

This study develops and applies a response surface methodology (RSM) for achieving optimal design for hydraulic structures in irrigation-water-delivery systems in canal networks. This approach provides a means of understanding system behavior through developing a response surface in terms of a mathematical expression representing system performance as affected by design decisions. Design decisions include pipe diameters for diversion and regulating structures. Simulation of steady spatially varied flow was incorporated into the response surface methodology to determine high-performance low-cost solutions.

Objectives of adequacy, efficiency dependability, and equity of water delivery were considered in defining water delivery performance. Fuzzy membership functions were used to address subjectivity associated with interpreting expected values of performance measures associated with each of the prescribed objectives.

This study is an extension of a previous study by Alshaikh [1]. That study reported the application of RSM on a single canal case while herein RSM was used for the case of a canal network. Though, in general, RSMs for large-scale branched systems are computationally intensive, this proposed methodology overcomes this drawback. The approach constitutes a significant easy-to-use step forward in the development of comprehensive systems-scale techniques for the design of structural components of irrigation-water-delivery systems.     

洮河流域纳纳河山洪灾害临界雨量分析计算

临界雨量是指典型流域山洪、泥石流、滑坡等自然灾害“恰好”能够发生所对应的时段最小降雨量值。在《山洪灾害临界雨量分析计算细则》规定的基础上,经过实践摸索提出了综合分析临界雨量初值的几种方法,并以黄河支流洮河流域纳纳河为例,进行了临界雨量的分析计算。计算结果表明,所采用的分析计算方法对类似流域山洪泥石流临界雨量的分析计算具有借鉴意义。     

淮河流域和长江中下游流域旱涝年的划分

利用1951—2007年国家气象信息中心提供的756站逐日降水资料,通过计算6—7月降水标准差,确定淮河流域和长江中下游流域降水变率最大的站点,分别计算各站与这两个流域降水变率最大的站点相关系数,把通过显著性检验的站点分别作为淮河流域和长江中下游流域的代表站。利用两流域代表站的标准化降水指数确定了1951—2007年的旱涝年份:淮河流域的旱年为1952年、1959年、1961年等共10 a,涝年为1954年、1956年、1957年等共9 a;长江中下游流域的旱年为1952年、1958年、1961年等共11 a,涝年为1954年、1969年、1980年等共10 a。结合水文资料进行修订后,确定了1951—2007年淮河流域和长江流域因梅雨季降水而导致的洪涝年份。     

A local alignment approach to similarity analysis of industrial alarm flood sequences

Similar alarm sequence alignment algorithms have been used to find similar alarm floods in the historical database for the prediction and prevention of alarm floods. However, the existing modified Smith–Waterman (SW) algorithm has a high computation complexity, preventing its online applications within a tolerable computation time period. This paper proposes a new local alignment algorithm, based on the basic local alignment search tool (BLAST). The novelty of the proposed algorithm is three-fold. First, a priority-based similarity scoring strategy makes the proposed algorithm more sensitive to alarms having higher alarm priorities. Second, a set-based pre-matching mechanism avoids unnecessary computations by excluding all irrelevant alarm floods and alarm tags. Third, the seeding and extending steps of the conventional BLAST are adapted for alarm floods, which reduce the searching space significantly. Owing to the novelties, the proposed algorithm is much faster in computation and provides a higher alignment accuracy than the SW algorithm. The efficiency of the proposed algorithm is demonstrated by industrial case studies based on the historical alarm floods from an oil conversion plant.