共查询到20条相似文献，搜索用时 46 毫秒
1.
Since water supply failure is one of the primary impacts of drought, drought risk should be quantified in the context of a lack of available water. To assess the drought risk, water supply system performance indices such as reliability, resiliency, and vulnerability are usually introduced as they correspond to primary drought characteristics, i.e., frequency, duration, and magnitude. In this study, we developed a drought risk index (DRI) through weighted averaging the performance indices derived using bivariate drought frequency analysis. We suggested two types of DRI: observed DRI (DRI_O) and designed DRI (DRI_D). DRI_O was calculated using an observed (or synthesized) time series of water shortages. DRI_D was estimated from the bivariate drought frequency curves, which are the probabilistic magnitudes of water shortages corresponding to a particular duration. The historical maximum drought event that represents the maximum DRI_O has generally been used as the target security level. However, we could establish a practically applicable target security level considering that the future water supply failure risk is represented by DRI_D. We defined regional drought safety criteria in this study by comparing DRI_O and DRI_D. Application of the criteria to the Nakdong river basin in South Korea showed that W1 (Byeongseongcheon) and W4 (Hyeongsangang) had the lowest and highest drought risk, respectively, and the drought safety criteria showed an average range of 5–20 years. 相似文献
2.
Revisiting hydrological drought propagation and recovery considering water quantity and quality 总被引：2，自引：0，他引：2
Climate extremes, in particular droughts, are significant driving forces towards riverine ecosystem disturbance. Drought impacts on stream ecosystems include losses that can be either direct (e.g., destruction of habitat for aquatic species) or indirect (e.g., deterioration of water quality, soil quality, and increased chance of wildfires). This paper combines hydrologic drought and water quality changes during droughts and represents a multistage framework to detect and characterize hydrological droughts while considering water quality parameters. This method is applied to 52 streamflow stations in the state of California, USA, over the study period of 1950–2010. The framework is assessed and validated based on two drought events declared by the state in 2002 and 2008. Results show that there are two opposite drought propagation patterns in northern and southern California. In general, northern California indicates more frequent droughts with shorter time to recover. Chronology of drought shows that stations located in southern California have not followed a specific pattern but they experienced longer drought episodes with prolonged drought recovery. When considering water quality, results show that droughts either deteriorate or enhance water systems, depending on the parameter of interest. Undesirable changes (e.g., increased temperature and decreased dissolved oxygen) are observed during droughts. In contrast, decreased turbidity is detected in rivers during drought episodes, which is desirable in water systems. Nevertheless, water quality deteriorates during drought recovery, even after drought termination. Depending on climatic and streamflow characteristics of the watersheds, it was found that it would take nearly 2 months on average for water quality to recover after drought termination. 相似文献
3.
水文干旱多变量联合设计及水库影响评估 总被引：2，自引：1，他引：1
基于东江流域博罗站月径流数据,采用游程理论提取水文干旱事件.选用Meta-Gaussian Copula函数,统计模拟水文干旱指标的多变量联合分布.采用Kendall联合重现期和最大可能权函数,设计给定联合超越重现期的水文干旱指标组合值,并定量评估水库径流调节作用对水文干旱多变量联合特征的影响.结果表明:东江流域水文干旱历时、强度和峰值的统计优选分布均为韦布尔分布.干旱指标之间具有较高的正相关性,Meta-Gaussian Copula能够很好地模拟水文干旱指标两变量和三变量联合分布.基于任意两个变量联合设计和三变量联合设计,干旱指标设计组合值位于同频位置附近,且同一个干旱指标设计值在不同变量组合之间差别较小.水库径流调节作用对于缓解东江流域水文干旱效果明显,同一组干旱指标的多变量联合超越重现期在水库影响下明显变大.联合超越重现期越小,水库对联合设计值的影响程度越大.根据目前水库运行模式,若要满足河道内最小管理流量目标,联合超越重现期10 a一遇的干旱历时、强度和峰值依然达到了约3.89~4.04月、7.20~7.97亿m3和2.99~3.12亿m3. 相似文献
4.
MIKE BONELL 《水文科学杂志》2013,58(5):809-810
Abstract Since droughts are natural phenomena, their occurrence cannot be predicted with certainty and thus it must be treated as a random variable. Once drought duration and magnitude have been found objectively, it is possible to plan for the transport of water in known quantities to drought-stricken areas either from alternative water resources or from water stored during wet periods. The summation of deficits over a particular period is referred to as the drought magnitude. Drought intensity is the ratio of drought magnitude to its duration. These drought properties at different truncation levels provide significant hydrological and hydrometeorological design quantities. In this study, the run analysis and z-score are used for determining drought properties of given hydrological series. In addition, kriging is used as a spatial drought analysis for mapping. This study is applied to precipitation records for Istanbul, Edirne, Tekirdag and Kirklareli in the Trakya region, Turkey and then the drought period, magnitude and standardized precipitation index (SPI) values are presented to depict the relationships between drought duration and magnitude. 相似文献
5.
干旱是洞庭湖区长期以来面临的严重自然灾害之一,给周边人们的生产生活造成了极大的影响.针对2006和2011年洞庭湖区发生的极端干旱事件,借助遥感影像大范围、时空连续的优势,结合湖区水文气象等观测资料,从时空两方面阐释了洞庭湖在典型干旱年份水域分布及变化过程,进一步从温度、降水、径流以及蓄水量等方面对比分析不同干旱事件发生、发展过程的一致性和差异性.研究结果表明:2006年干旱大致从7月开始,至12月结束.水面淹没范围由湖心向周边扩展,到7月达到最大值,8月提前进入枯水期,减小范围主要集中在东洞庭湖外围和南洞庭湖的北边.2006年干旱属于由入湖径流减少主导的水文干旱事件;2011年的干旱则从4月开始,至11月结束,在9月以后干旱继续加重.水面淹没范围在6月急剧增大且一直到8月都维持在较高的水平,涨水期水面由中心向四周淹没,退水期水面变化范围与涨水期相反.2011年干旱是由流域降水减少引起的水文和气象干旱事件.研究结果揭示了洞庭湖区干旱成因的多样性和复杂性,对于制定科学合理的干旱灾害防范措施,减缓区域的生态环境问题等具有一定的指导和借鉴意义. 相似文献
6.
Roger A. Pielke Sr. Nolan Doesken Odilia Bliss Tara Green Clara Chaffin Jose D. Salas Connie A. Woodhouse Jeffrey J. Lukas Klaus Wolter 《Pure and Applied Geophysics》2005,162(8-9):1455-1479
The 2002 drought in Colorado was reported by the media and by public figures, and even by a national drought-monitoring agency, as an exceptionally severe drought. In this paper we examine evidence for this claim. Our study shows that, while the impacts of water shortages were exceptional everywhere, the observed precipitation deficit was less than extreme over a good fraction of the state. A likely explanation of this discrepancy is the imbalance between water supply and water demand over time. For a given level of water supply, water shortages become intensified as water demands increase over time. The sobering conclusion is that Colorado is more vulnerable to drought today than under similar precipitation deficits in the past. 相似文献
7.
This paper compares two generators of yearly water availabilities from sources located at multiple sites with regard to their ability to reproduce the characteristics of historical critical periods and to provide reliable results in terms of the return period of critical sequences of different length. The two models are a novel multi-site Markov mixture model explicitly accounting for drought occurrences and a multivariate ARMA. In the case of the multisite Markov mixture model parameter estimation is limited to a search in the parameter space guided by the value of parameter λ to show the sensitivity of the model to this parameter. Application to two of the longest time series of streamflows available in Sicily (Italy) shows that the models can provide quite different results in terms of estimated return periods of historic droughts, although they seem to perform more uniformly when it comes to simulate drought-related statistics such as drought length, severity and intensity. The role of parameter selection for the multisite Markov mixture model and of the marginal probability of generated flows in providing results consistent with the characteristics of the observed series is discussed. Both models are applied to the system of sources supplying the city of Palermo (Sicily) and its environs showing the applicability of the newly developed multisite Markov mixture model to medium-to-large scale water resources systems. 相似文献
8.
Drought hotspot identification requires continuous drought monitoring and spatial risk assessment. The present study analysed drought events in the agriculture‐dominated mid‐Mahanadi River Basin in Odisha, India, using crop water stress as a drought indicator. This drought index incorporated different factors that affect crop water deficit such as the cropping pattern, soil characteristics, and surface soil moisture. The drought monitoring framework utilized a relevance vector machine model‐based classification that provided the uncertainty associated with drought categorization. Using the proposed framework, drought hotspots are identified in the study region and compared with indices based on precipitation and soil moisture. Further, a bivariate copula is employed to model the agricultural drought characteristics and develop the drought severity–duration–frequency (S–D–F) relationships. The drought hotspot maps and S–D–F curves are developed for different locations in the region. These provided useful information on the site‐specific drought patterns and the characteristics of the devastating droughts of 2002 and 2012, characterized by an average drought duration of 7 months at several locations. The site‐specific risk of short‐ and long‐term agricultural droughts are then investigated using the conditional copula. The results suggest that the conditional return periods and the S–D–F curves are valuable tools to assess the spatial variability of drought risk in the region. 相似文献
9.
Sangeun Lee Suhaimi Abdul-Talib Heekyung Park 《Aquatic Sciences - Research Across Boundaries》2012,74(2):213-227
Numerous publications document increasing consensus in the scientific community that climate change will increase the severity
and frequency of drought. However, constructing large infrastructures is often viewed as an unreliable and inefficient option
in dealing with the problem of drought, owing to unpredictability of climate change. This study aims at illustratively presenting
that there is much room to improve drought management without resorting solely to infrastructure options. The adaptiveness
concept is first explained to examine the reasons of failure in drought management and appropriate options from the viewpoint
of a systems approach. Thereafter, a Korean water scarcity case is defined as the system dynamics model. The model is implemented
to include movement of water via the reservoir and water supply facilities, the operating rules of the reservoir, and the
relation between water scarcity and customer stress. Simulation results demonstrate that adaptiveness of drought management
was low because of untimely or limited options of the reservoir operator. They also show that most customer stress could be
largely mitigated by two options chosen from the adaptiveness concept. It is finally concluded that drought management needs
to be addressed with consideration of the adaptiveness concept before deciding solely on expansion of infrastructure upon
facing challenges due to climate change. 相似文献
10.
Jessica Fennell Josie Geris Mark E. Wilkinson Ronald Daalmans Chris Soulsby 《水文研究》2020,34(22):4190-4210
Climate change, combined with industrial growth and increasing demand, could result in serious future water shortages and related water quality and temperature issues, especially for upland and humid areas. The extreme 2018 drought that prevailed throughout Europe provided an opportunity to investigate conditions likely to become more frequent in the future. For an upland rural catchment utilised by the distilling industry in North-East Scotland, a tracer-based survey combined discharge, electrical conductivity, stable water isotopes and temperature measurements to understand the impacts of drought on dominant stream water and industry water sources, both in terms of water quantity and quality (temperature). Results showed that water types (groundwater, ephemeral stream water, perennial stream water and water from small dams) were spatially distinct and varied more in space than time. With regards to the drought conditions we found that streams were largely maintained by groundwater during low flows. This also buffered stream water temperatures. Water types with high young water fractions were less resilient, resulting in streams with an ephemeral nature. Although our results demonstrated the importance of groundwater for drought resilience, water balance data revealed these storage reserves were being depleted and only recovered towards the end of the following year because of above average rainfall in 2019. Increased storage depletion under continued trends of extreme drought and water abstraction could be addressed via informed (nature based) management strategies which focus on increasing recharge. This may improve resilience to droughts as well as floods, but site specific testing and modelling are required to understand their potential. Results could have implications for management of water volumes and temperature, particularly for the sustainability of an historic industry, balancing requirements of rural communities and the environment. 相似文献
11.
Shifts in discharge‐concentration relationships as a small catchment recover from severe drought 
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下载免费PDF全文 This paper provides evidence of the recovery of a small, moorland catchment to a severe drought, the most extreme on record in the UK. We present a detailed water quality time series for the post‐drought recovery period, from the first significant storm event at the end of the drought through three very wet months during which time the catchment fully wetted up. High‐frequency observations were obtained using pump water samplers, at 15‐min intervals for storm events and 2 hourly at other times. There are significant shifts in discharge‐concentration response as the catchment wets up; initial behaviour is very different to later storms. Extreme drought may become more common in a warmer world, so it is increasingly important to understand water quality response during and after such episodes, if their impact on water resources and in‐stream ecology is to be better anticipated. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
12.
Drought events are increasing worldwide. Socio-economic drought is the least investigated type of drought, and is the only type for which water demand is taken into consideration. In this research, socio-economic drought was studied in Lake Mead, USA, using a multivariate standardized water-scarcity index (MSWSI) over the period 1990–2014, combining two water-scarcity indices based on time series of inflow, outflow, reservoir storage, and water demand. The inflow and outflow were determined from streamgage data, and reservoir storage from lake level data; demand was based on water pumped by the Southern Nevada Water Authority. Missing observations in input streamgage data were filled through regression modeling. The results indicate that Lake Mead has been in socio-economic drought since 2000, with the most severe drought occurring between 2006 and 2012, and the highest intensity drought in April–July 2014. The Lake Mead droughts revealed through the MSWSI are consistent with those reported in US Drought Monitor (USDM) products. The temporal behavior of MSWSI provides an insight into the socio-economic effects of droughts not captured by USDM products. 相似文献
13.
The effect of conservation practices in sloped croplands on soil hydraulic properties and root‐zone moisture dynamics 下载免费PDF全文
下载免费PDF全文 Rain‐induced erosion and short‐term drought are the two factors that limit the productivity of croplands in the red soil region of subtropical China. The objective of this study was to estimate the effects of conservation practices on hydraulic properties and root‐zone water dynamics of the soil. A 3‐year experiment was performed on a slope at Xianning. Four treatments were evaluated for their ability to reduce soil erosion and improve soil water conditions. Compared with no practices (CK) and living grass strips (GS), the application of polyacrylamide (PAM) significantly reduced soil crust formation during intense rainfall, whereas rice straw mulching (SM) completely abolished soil crust formation. The SM and PAM treatments improved soil water‐stable aggregates, with a redistribution of micro‐aggregates into macro‐aggregates. PAM and SM significantly increased the soil water‐holding capacity. These practices mitigated the degradation of the soil saturated hydraulic conductivity (Ks) during intense rainfalls. These methods increased soil water storage but with limited effects during heavy rainfalls in the wet period. In contrast, during the dry period, SM had the highest soil water storage, followed by PAM and CK. Grass strips had the lowest soil water storage because of the water uptake during the vigorous grass growth. A slight decline in the soil moisture resulted in a significant decrease in the unsaturated hydraulic conductivity (Ku) of the topsoil. Therefore, the hydraulic conductivity in the field is governed by soil moisture, and the remaining soil moisture is more important than improving soil properties to resist short‐term droughts. As a result, SM is the most effective management practice when compared with PAM and GS, although they all protect the soil hydraulic properties during wet periods. These results suggest that mulching is the best strategy for water management in erosion‐threatened and drought‐threatened red soils. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
14.
Streamflow drought time series forecasting 总被引：5，自引：2，他引：5
Reza Modarres 《Stochastic Environmental Research and Risk Assessment (SERRA)》2007,21(3):223-233
Drought is considered to be an extreme climatic event causing significant damage both in the natural environment and in human
lives. Due to the important role of drought forecasting in water resources planning and management and the stochastic behavior
of drought, a multiplicative seasonal autoregressive integrated moving average (SARIMA) model is applied to the monthly streamflow
forecasting of the Zayandehrud River in western Isfahan province, Iran. After forecasting 12 leading month streamflow, four
drought thresholds including streamflow mean, monthly streamflow mean, 2-, 5-, 10- and 20-year return period monthly drought
and standardized streamflow index were chosen. Both observed and forecasted streamflow showed a drought period with different
severity in the lead-time. This study also demonstrates the usefulness of SARIMA models in forecasting, water resources planning
and management. 相似文献
15.
洞庭湖是长江中游重要的通江湖泊,水系格局复杂.近年来在气候变化和人类活动的双重影响下,江湖关系发生变化,湖泊水文干旱事件频发.基于洞庭湖、流域和长江干流水文站点的实测数据,通过标准化水位指数和标准化径流指数识别了水文干旱事件,并运用Copula函数分析了洞庭湖-流域-长江系统水文干旱的联合概率分布特征.结果表明:在年尺度上,1964—2016年间洞庭湖共发生了9次水文干旱事件,水文干旱的发生概率为14.01%,洞庭湖-流域系统、洞庭湖-长江系统的水文干旱联合概率分别为9.65%和8.58%,表明年尺度上流域来水对洞庭湖水文干旱的影响更大.在季节尺度上,洞庭湖-流域系统春季水文干旱联合概率最高,且两者同时发生水文干旱事件的次数最多,表明洞庭湖春季水文干旱与流域入湖补给减少有密切关系;而洞庭湖-长江系统,其秋季水文干旱联合概率最大,尤其自2003年以后更加极端和频发,这一方面受秋季降水减少和流域内人类活动的影响,另一方面三峡水库秋季蓄水使长江中下游干流水位降低,长江对湖泊顶托作用减弱也是重要原因之一. 相似文献
16.
Recent studies have highlighted the importance of understanding ecohydrological drought feedbacks to secure water resources under a changing climate and increasing anthropogenic impacts. In this study, we monitored and modelled feedbacks in the soil–plant-atmosphere continuum to the European drought summer 2018 and the following 2 years. The physically based, isotope-aided model EcH2O-iso was applied to generic vegetation plots (forest and grassland) in the lowland, groundwater-dominated research catchment Demnitzer Millcreek (NE Germany; 66 km2). We included, inter alia, soil water isotope data in the model calibration and quantified changing “blue” (groundwater recharge) and “green” (evapotranspiration) water fluxes and ages under each land use as the drought progressed. Novel plant xylem isotope data were excluded from calibration but were compared with simulated root uptake signatures in model validation. Results indicated inter-site differences in the dynamics of soil water storage and fluxes with contrasting water age both during the drought and the subsequent 2 years. Forest vegetation consistently showed a greater moisture stress, more rapid recovery and higher variability in root water uptake depths from a generally younger soil water storage. In contrast, the grassland site, which had more water-retentive soils, showed higher and older soil water storage and groundwater recharge fluxes. The damped storage and flux dynamics under grassland led to a slower return to younger water ages at depth. Such evidence-based and quantitative differences in ecohydrological feedbacks to drought stress in contrasting soil-vegetation units provide important insights into Critical Zone water cycling. This can help inform future progress in the monitoring, modelling and development of climate mitigation strategies in drought-sensitive lowlands. 相似文献
17.
The Earth’s surface fluid mass redistribution, e.g., groundwater depletion and severe drought, causes the elastic surface deformation, which can be measured by global positioning system (GPS). In this paper, the continuous GPS observations are used to estimate the terrestrial water storage (TWS) changes in southwestern USA, which have a good agreement with TWS changes derived from Gravity Recovery And Climate Experiment (GRACE) and hydrological models. The seasonal variation is mostly located in the Rocky mountain range and Mississippi river watershed. The largest amplitude of the seasonal variation is between 12 and 15 cm in equivalent water thickness. The timing and duration of TWS anomalies caused by the severe drought in 2012 are observed by the GPS-derived TWS, which are confirmed by the GRACE results. Different hydrological models are further used for comparison with GPS and GRACE results. The magnitude of TWS depletion from GRACE and GPS observations during the drought is larger than that from hydrological models, which indicates that the drought was caused by comparable groundwater and surface water depletion. The interannual TWS changes from GPS are also consistent with the precipitation pattern over the past 6 years, which further confirms the severe drought in 2012. This study demonstrates that continuous GPS observations have the potential as real-time drought indicator. 相似文献
18.
《Limnologica》2016
Shallow coastal lakes are under increasing pressure from climate change. Low rainfall and reduced run-off contributed to an unprecedented drought in Lake St. Lucia since 2002. Physico-chemical variables and microalgal biomass are analysed, tracking the transition from drought (2009) to wet conditions (2014). Despite low water levels and habitat loss due to desiccation, microalgal biomass remained high mainly due to cyanobacterial contribution. The system exhibited distinct spatio-temporal patterns in terms of salinity, water level, DIN, microalgal biomass and class composition associated with the drought, transition and wet climatic phases. Regime shifts were detected, coinciding with the end of the drought and the beginning of the wet phase. The St. Lucia ecosystem responds rapidly to changes in climatic phases while sustaining microalgal stocks; it may therefore be relatively resilient to extreme drought events. 相似文献
19.
A bivariate pareto model for drought 总被引：2，自引：2，他引：0
Saralees Nadarajah 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(6):811-822
Univariate Pareto distributions have been so widely used in hydrology. It seems however that bivariate or multivariate Pareto
distributions have not yet found applications in hydrology, especially with respect to drought. In this note, a drought application
is described by assuming a bivariate Pareto model for the joint distribution drought durations and drought severity in the
State of Nebraska. Based on this model, exact distributions are derived for the inter arrival time, magnitude and the proportion
of droughts. Estimates of 2, 5, 10, 20, 50 and 100 year return periods are derived for the three variables, drought duration,
drought severity and the pairwise combinations: (drought duration, drought severity), (inter arrival time of drought, proportion
of drought) and (drought duration, drought magnitude). These return period estimates could have an important role in hydrology,
for example, with respect to measures of vegetation water stress for plants in water-controlled ecosystems. 相似文献
20.
太湖流域宜溧河地区水体水质状况及营养状态评价 总被引：17，自引：5，他引：17
宜溧河流域是太湖的主要集水流域，流域水体的水质状况及营养状态与太湖的水质状况与营养状态密切相关，本研究根据2000年12月14-15日以及2001年4月18-19日两次大规模的水质同步监测结果，对流域平原河网地区水体的水质状况及营养状态进行了系统综合的评价，评价结果表明：不管是平水期还是枯水期，河网水体的水质状况都较差，营养水平较高；在枯水期间，受多种因素的综合影响，水体的水质状况呈现恶化趋势，营养盐含量也有所升高。 相似文献