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1.
Stream restoration efforts, particularly within meadow systems, increasingly rely on ‘pond and plug’ type methods in which (a) alluvial materials are excavated from the floodplain, forming ponds; (b) excavated alluvial materials are used to plug incised channels and (c) smaller dimension channels are restored to the floodplain surface. A commonly stated objective of these efforts is to restore ecologically significant hydrological processes to degraded riparian systems. However, little research has been conducted to evaluate and quantify the restoration of these hydrological processes. Direct comparisons of pre‐ and post‐restoration hydrological observations are often misleading due to an inter‐annual climatic variability. To overcome this issue and accurately quantify the hydrological effects of restoration, we developed, calibrated and validated a hydrological model of a 230 ha mountain meadow along a 3.6 km restored reach of Bear Creek in the northeastern California. We then applied the model to simulate the pre‐ and post‐restoration scenarios by altering the floodplain topography and stream channel networks. Our results document three general hydrological responses to the meadow restoration effort: (1) increased groundwater levels and volume of subsurface storage; (2) increased frequency/duration of floodplain inundation and decreased magnitude of flood peaks and (3) decreased annual runoff and duration of baseflow. This study supports and quantifies the hypothesis that ‘pond and plug’ type stream restoration projects have the capacity to re‐establish hydrological processes necessary to sustain riparian systems. In addition, the results of this study can be used to improve quantitative objectives for ‘pond and plug’ type stream restoration activities in similar settings. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Connection between rivers and their floodplain is critical to the function of fluvial systems; however, there has been little research quantitatively examining the dynamics of this interaction for large, alluvial rivers. Critical questions include the following: What are the rates and mechanisms of materials and energy exchange, and in what ways does the exchange impact ecosystem functioning? To address these questions, we built a simple model of a hypothetical reach of the Lower Mississippi River (LMR) containing a single backwater. The model is based on empirical data obtained from the LMR system. Our primary objectives for the model were to assess potential backwater impacts on river nitrate transport and in subsidizing phytoplankton biomass to the main channel. Simulations run over a 10‐year period suggest that on an annual basis, (a) LMR backwaters remove NO3–N, and it would require a temporal mean of 34,400 ha functioning like the model backwater, or 2.8 times the current area of oxbow lakes, to eliminate 100% of the river flux of NO3–N of our study region; (b) it would require inputs of phytoplankton from a mean of 5,242 ha of sites functioning like the model backwater to produce observed river flux of phytoplankton biomass; and (c) backwater function is sensitive to the controlling elevation in linking channels hence subject to management. Although simple, this model is a useful first step in quantifying the significance of river–backwater connectivity on ecological processes of the LMR system. 相似文献
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传统的水电厂、变电站设计洪水计算方法都是以经验公式或推理公式为基础建立的简单计算法,计算结果的正确率都较低。采用MIKE SHE分布式水文模型,结合GIS与RS技术,对贵州喀斯特地貌区的六硐河甲茶水电站进行了洪峰流量计算,并与其他模型方法的计算结果进行了比较。结果表明,在洪峰计算中,MIKE SHE模型具有模拟结果更加精确、详细等独特优势,且适用于喀斯特地貌区。该模型的成功使用为今后类似地区的洪峰计算奠定了坚实的基础。 相似文献
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The Atchafalaya River Basin in south‐central Louisiana (USA) comprises the largest contiguous river–floodplain swamp in North America and functions as a distributary for the Mississippi River to the Gulf of Mexico. We assessed the impact of the annual flood pulse on fisheries production at a basin‐wide scale. We modelled flood duration (days/year Butte LaRose gauge height >3.6 m) and magnitude (mean daily gauge height) against long term (1987–2009) fishery‐independent and fishery‐dependent data on largemouth bass (Micropterus salmoides), crappie (Pomoxis spp.), blue catfish (Ictalurus furcatus), buffalofish (Ictiobus spp.), gizzard shad (Dorosoma cepedianum) and crayfish (Procambarus spp.). When the Atchafalaya River at Butte LaRose is at flood stage (≥ 3.6 m gauge height) for approximately 121–157 days/year, then annual relative abundances of largemouth bass, crappie, blue catfish and buffalofish are optimized during the fall (October–December). In contrast to the tenets of the flood pulse concept, gizzard shad abundance was optimized during low flow years, when flood duration is ≤10 days/year. Annual proportion of age‐1 largemouth bass was associated positively with flow magnitude during the previous year, whereas proportions of age‐2 largemouth bass and crappie were associated positively with flood magnitude 2 years prior to the fish sample. Results for commercial production metrics were ambiguous. Crayfish catches were associated positively with flood magnitude and duration, whereas gizzard shad landings peaked at a relatively small flood magnitude level and were not related to flood duration. Blue catfish and buffalofish annual landings were not influenced by the annual flood pulse. The annual flood pulse can be managed to optimize the availability of recreational (largemouth bass and crappie) and some commercial fisheries resources (blue catfish and crayfish). We estimate that a minimum discharge of 8807 m3 s?1 is required at the river's source for approximately 4–5 months during the winter–spring months to optimize fisheries production. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Reduced river–floodplain connectivity can decrease fisheries production and cause ecological and socioeconomic consequences. In 2011, the largest flood on record in the Missouri River since 1898 nearly eliminated connectivity between an embayment (Hipple Lake) and Lake Sharpe, impeding movement of walleye (Sander vitreus) and a forage fish, gizzard shad (Dorosoma cepedianum). Thus, we used otolith chemistry to quantify Hipple Lake's natal contribution to Lake Sharpe's gizzard shad population and forecast effects of connectivity loss on the reservoir's socioeconomically important walleye fishery. Fish were classified to natal habitats with 79–89% accuracy, with most gizzard shad (64%) hatching in floodplain habitats (i.e., embayments, tributaries, canals, and stilling basins). Hipple Lake contributed 12% of gizzard shad to Lake Sharpe, more than a tributary (4%) and embayment (0%) but less than a canal (27%) and stilling basin (21%). Hipple Lake (178 acres) covers 0.31% of Lake Sharpe (56,884 acres), so its natal contribution is 38 times what would be expected if contribution was linearly related to area. Sediment and water management to maintain connectivity between Lake Sharpe and Hipple Lake and other floodplain habitats is important for continued gizzard shad production and prey supply for the walleye fishery. Otolith chemistry facilitates assessment of gizzard shad natal contributions in different habitats, serving as a fisheries management tool to inform floodplain habitat protection and rehabilitation after floods. 相似文献
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分布式水文模型是通过水循环的动力学机制来描述和模拟流域水文过程的数学模型。MIKE SHE作为一种分布式水文模型被越来越多地运用到流域规划、水资源管理、水资源评价等方面。要成功地建立起一个MIKE SHE模型除需要有充分的基础资料收集和前期准备工作外,后期的模型率定也是至关重要的一环。本文就渗透系数和给水度在MIKE SHE模型率定阶段的作用进行了分析。 相似文献
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On meandering rivers with well‐developed floodplains, bankfull stage has geomorphological and ecological significance because it approximates the level of connection between the channel and the floodplain. As a river rises to bankfull stage, sediment begins to be deposited on the floodplain, wetlands are progressively inundated and organisms migrate between the channel and floodplain habitats. On many rivers large headwater dams have reduced the frequency and duration of floodplain inundation downstream. However, the lack of reliable pre‐regulation flow data has made it difficult to quantify the effects of river regulation. This study used historical regulated and modelled natural flow data to determine the effects of regulation on the frequency and duration of bankfull flows on the Murrumbidgee River, one of Australia's largest and most heavily regulated rivers. In combination with floodplain surveys the flow data show that regulation has halved the frequency and duration of bankfull flows. This reduction in channel–floodplain connection has implications for the ecological health of the Murrumbidgee River. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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为提供开都河水库优化调度和水资源科学管理的依据,应用MIKE耦合模型进行流域中短期径流预报。选取欧洲天气预报中心（ECMWF）气象预报模式作为气象数据输入,构建包含6个子模块（蒸散发、非饱和带、饱和带、坡面流、河流与湖泊）和融雪模块的MIKE SHE模型。将MIKE Hydro river模型作为河道汇流计算与MIKE SHE模型耦合对未来10 d径流信息进行预报。选用相关系数（R2）、纳什效率系数（NSE）和相对误差（BAIS）评价模型率定与验证结果,添加预报效率（E）评价模型预报精度。研究表明：在开都河日尺度径流模拟中,验证期R2和NSE均大于0.70,相对误差仅为-15%,可见模拟径流与实测径流之间具有较好的拟合性和相关性;预报期的NSE=0.53、R2=0.61、E=0.51,说明模拟值与实测值的相关性达0.61。MIKE耦合模型的中短期径流预报可为开都河流域水资源优化利用提供参考。 相似文献
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MIKE SHE模型在灞河径流模拟中的应用研究 总被引：1，自引：0，他引：1
以灞河流域作为研究区域,依据该流域水文气象1990-2010年实测资料,采用MIKE SHE模型对流域径流进行模拟研究,利用Arc Gis等技术建立了模型数据库,对模型参数进行了率定和验证,使用多目标(均方根平方误差、模型效率系数和决定系数)对模型适用性进行了评价。结果表明:年径流模拟效果比较好,MIKE SHE模型在灞河流域的适用性较好,研究所率定的参数可为进一步研究灞河流域水资源利用与管理提供依据。 相似文献
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为了评估西控工程对望虞河西岸地区造成的防洪影响,以望虞河西岸为研究区域并结合其水文特性,构建了适合于模拟平原河网地区产汇流过程的MIKE11水文水力模型并利用当地降雨、水位等实测资料进行了率定。通过模拟50年一遇设计暴雨情况下的不同工况,得到研究区域内水系各节点的水位等要素变化情况,并依此分析了西控工程对望虞河西岸地区造成的防洪影响。结果表明:西控工程运行后,研究区域内重要节点的最高水位抬升明显,部分地区有遭受洪水淹没的风险;MIKE11水文水力模型对于分析平原河网地区河流沿线闸控影响具有较高的应用价值。 相似文献
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The Mississippi and Missouri Rivers experienced flooding in 1993 that fell outside the annual predictable flood period of spring and early summer. Flooding began in late June, peaked in late July (25 232 m3/s on the upper Mississippi and 21 240 m3/s on the Missouri) and remained at or near flood stage into October 1993. This study was performed to determine if disturbance by an unpredicted flood event would alter trophic dynamics of river–floodplain systems by creating shifts in the composition of organic matter available to consumers. The Ohio River, which did not flood during the same period, was examined for comparison. Stable isotopic ratios of carbon and nitrogen from samples collected in 1993 and 1994 were used to characterize potential food sources and determine linkages between food sources and invertebrate and fish consumers. Pairwise contrasts, performed separately for each river, indicated there were few interannual differences in δ13C and δ15N of organic matter sources and consumers. Between sample period (flood year versus normal water year) trends in both flooded rivers were similar to between‐year trends observed for the Ohio River. Trophic structure of the Mississippi and Ohio Rivers was similar in both years, with fine and ultra‐fine transported organic matter and dissolved organic matter representing the major sources of organic matter. Overlapping isotopic signatures in the Missouri River made tracking of sources through the consumers difficult, but similarities in δ13C and δ15N between years indicated trophic structure did not change in response to the flood. The results suggest that consumers continued to rely on sources of organic matter that would be used in the absence of the unpredicted 1993 flood. It is proposed that trophic structure did not change in response to flooding in the Mississippi and Missouri Rivers because both rivers exhibited the same trends observed in the Ohio River. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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In October 2000, the flow of the River Murray entering South Australia was increased from 32 000 to 42 050 ML day?1 by release of water from an offstream reservoir, and a downstream weir was raised by 500 mm to impound the flood and enhance local floodplain inundation. The flood was maintained for about two weeks, although the duration of inundation was longer at low elevations on the floodplain. Vegetation at three sites was surveyed before and after the flood to examine the impact of inundation on the growth and germination of flood‐tolerant, flood‐dependent and flood‐intolerant species. Among 32 recorded species, Atriplex vesicaria (bladder saltbush, Chenopodiaceae), Sporobolus mitchellii (rats tail couch, Graminae) and Sarcocornia quinqueflora (samphire, Chenopodiaceae) accounted for nearly 82% of the total cover/abundance. Flood‐tolerant and flood‐dependent species (e.g. S. mitchellii) grew and germinated and flood‐intolerant species (e.g. A. vesicaria) senesced. No aquatic plants germinated or established, despite favourable conditions, suggesting an impoverished seed bank or grazing. Based on the growth but lack of germination of flood‐tolerant and flood‐dependent species, the value of small, occasional interventions in environmental flow management may be to maintain existing communities rather than restore degraded ones. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Prioritizing projects to improve cost‐effectiveness has become a common practice in natural resources management, especially in selecting sites for river restoration work. Previous studies for prioritizing road–stream crossing upgrade projects focused on either restoring river connectivity or reducing sedimentation, even though crossings can affect connectivity and sedimentation simultaneously. In this study, we simulated site selection to maximize the improvement of connectivity restoration and sedimentation reduction of three prioritization schemes targeting (a) river connectivity, (b) erosion risk, or (c) both objectives concurrently and compared the results. Furthermore, we examined the relationships between the cost‐effectiveness of prioritizations and watershed characteristics. We found significant differences among the effectiveness of prioritization objectives; thus, trade‐offs should be taken into consideration when prioritizing crossings. The incorporation of spatial interdependency among crossings and weighting objectives could significantly change the cost‐effectiveness. We also found that splitting the budget and using a portion to individually prioritize each objective could be more cost‐effective than using the whole budget to achieve concurrent objectives. Watershed characteristics like size and connectivity‐ and sedimentation‐related factors could be used to help identify effective management for both connectivity restoration and sedimentation control. 相似文献
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The Tonle Sap River (TSR) serves as a natural medium for the reversal flow between Tonle Sap Lake (TSL) and the Mekong River to sustain productivity and biodiversity in the TSR floodplain and TSL. Understanding the hydrological connectivity and its dynamics in the TSR, including its floodplain, is therefore important to support activities that aim to maintain ecological services in the TSR–TSL system. Thus, the main objective of this study is to examine the hydrological connectivity of the TSR and its floodplain by a modelling approach that integrates inundation patterns and sediment dynamics. The Caesar–Lisflood model was applied to describe inundation, sediment erosion, transport, and deposition in the TSR for the period of 2003–2013. The inundation areas connected to the TSR ranged from 140 to 2,327 km2, whereas the isolated inundation areas from the TSR ranged from 0.27 to 504 km2. Sediment dynamics showed its influence on inundation patterns and hydrological connectivity and could alter the yearly inundation ratio (defined as a normalized inundation frequency with a value ranging from 0 to 1) up to 0.8. Our approach provides a quantitative way to determine key factors (e.g., total inundation areas, seasonality, and connectivity of inundation patterns) for further investigation of ecological processes in relation to the inundation patterns and sediment dynamics in the TSR and TSL. 相似文献
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Jeremy E. Matt Kristen L. Underwood Rebecca M. Diehl K. S. Lawson Lindsay C. Worley Donna M. Rizzo 《河流研究与利用》2023,39(9):1795-1811
Centuries of human development have altered the connectivity of rivers, adversely impacting ecosystems and the services they provide. Significant investments in natural resource projects are made annually with the goal of restoring function to degraded rivers and floodplains and protecting freshwater resources. Yet restoration projects often fall short of their objectives, in part due to the lack of systems-based strategic planning. To evaluate channel-floodplain (dis)connectivity and erosion/incision hazard at the basin scale, we calculate Specific Stream Power (SSP), an estimate of the energy of a river, using a topographically based, low-complexity hydraulic model. Other basin-wide SSP modeling approaches neglect reach-specific geometric information embedded in Digital Elevation Models. Our approach leverages this information to generate reach-specific SSP-flow curves. We extract measures from these curves that describe (dis)connected floodwater storage capacity and erosion hazard at individual design storm flood stages and demonstrate how these measures may be used to identify watershed-scale patterns in connectivity. We show proof-of-concept using 25 reaches in the Mad River watershed in central Vermont and demonstrate that the SSP results have acceptable agreement with a well-calibrated process-based model (2D Hydraulic Engineering Center's River Analysis System) across a broad range of design events. While systems-based planning of regional restoration and conservation activities has been limited, largely due to computational and human resource requirements, measures derived from low-complexity models can provide an overview of reach-scale conditions at the regional level and aid planners in identifying areas for further restoration and/or conservation assessments. 相似文献
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为解决我国城市化进程中的水安全和水环境问题,结合海绵城市建设理念和河道综合整治目标,分析暴雨洪水管理模型(storm water management model,SWMM)和MIKE 11模型的适用范围、具备优势和存在不足。结果表明,SWMM广泛应用于径流总量控制和面源污染削减的模拟,但是无法模拟河道中污染物的对流扩散和生化过程;MIKE 11河网模型广泛应用于城市河道水量和水质模拟,可预测特定条件下的河道水环境变化情况,但是无法反映陆域面源污染对河道水质的冲击影响。构建SWMM-MIKE 11耦合模型,利用SWMM进行海绵设施和雨水管网模拟,将SWMM中管网排口径流作为边界条件导入到MIKE 11模型中,可以实现二者优势互补。 相似文献