FISH RECRUITMENT IS INFLUENCED BY RIVER FLOWS AND FLOODPLAIN INUNDATION AT APALACHICOLA RIVER,FLORIDA

High human demand for limited water resources often results in water allocation trade‐offs between human needs and natural flow regimes. Therefore, knowledge of ecosystem function in response to varying streamflow conditions is necessary for informing water allocation decisions. Our objective was to evaluate relationships between river flow and fish recruitment and growth patterns at the Apalachicola River, Florida, a regulated river, during 2003–2010. To test relationships of fish recruitment and growth as responses to river discharge, we used linear regression of (i) empirical catch in fall, (ii) back‐calculated catch, via cohort‐specific catch curves, and (iii) mean total length in fall of age 0 largemouth bass Micropterus salmoides, redear sunfish Lepomis microlophus and spotted sucker Minytrema melanops against spring–summer discharge measures in Apalachicola River. Empirical catch rates in fall for all three species showed positive and significant relationships to river discharge that sustained floodplain inundation during spring–summer. Back‐calculated catch at age 0 for the same species showed positive relationships to discharge measures, but possibly because of low sample sizes (n = 4–6), these linear regressions were not statistically significant. Mean total length for age 0 largemouth bass in fall showed a positive and significant relationship to spring–summer discharge; however, size in fall for age 0 redear sunfish and spotted sucker showed no relation to spring–summer discharge. Our results showed clear linkages among river discharge, floodplain inundation and fish recruitment, and they have implications for water management and allocation in the Apalachicola River basin. Managed flow regimes that reduce the frequency and duration of floodplain inundation during spring–summer will likely reduce stream fish recruitment. Copyright © 2012 John Wiley & Sons, Ltd.     

流域初始状态对环境同位素法划分流量的影响

在使用同位素示踪剂划分流量时,流域初始状态会对事件水和事件前水分割产生影响。为研究流域初始状态对环境同位素法划分流量的影响,以和睦桥流域2015—2016年间4场降雨事件为研究对象,根据稳定同位素含量(δ¹⁸O)确定其在流域出口断面径流的不同水源组成比例,着重分析流域不同初始流量和前期土壤含水量对流量过程线划分的影响。结果表明:流域出口径流总量中事件前水占优,洪峰流量以事件水为主;流域不同初始状态下同位素分割结果不同,表明该流域存在多种产流机制,流域初始流量与总径流系数及事件水贡献比例呈负相关;前期土壤含水量与事件水贡献比例的影响模式复杂多变,但在前期土壤含水量较高或前期降雨较多的情况下,总径流中事件水贡献比例将降低。     

Assessing Groundwater Contribution to Streamflow of a Large Alpine River with Heat Tracer Methods and Hydrological Modelling

The contribution of groundwater to streamflow in Alpine catchments is still poorly understood, despite the fact that it may heavily impact hydrological balance and stream habitats. This paper presents the results of a field campaign based on experiments with heat tracer methods to assess the hyporheic flow during the low‐flow period of a large Alpine river in Italy. These measurements were employed to validate a distributed hydrological model that can be used to asses river–groundwater interaction in both low‐flow and high‐flow conditions. The results show that groundwater may have a relevant role during low‐flow periods, by increasing river discharge and during floods, by subtracting direct run‐off that is stored in river banks. Copyright © 2015 John Wiley & Sons, Ltd.     

无测站流域径流预测区域化方法研究进展

无测站流域径流预测是地表水文研究的难题与挑战,而区域化方法,即将水文信息从有测站流域移植至无测站或缺测站流域估算径流量的过程,则为该问题提供了有效的解决办法。由于不同流域地文属性及气候特征各不相同,目前并无通用的方法,回归法、空间近似法及物理相似法是径流预测区域化研究中最常用的三种方法。基于此,本文阐明了三种方法的基本理论,综述了其研究进展、适用性及局限性,分析了区域化研究中常用水文模型及流域特征因子遴选的依据,总结了误差检验及不确定性分析的方法,并展望了径流预测区域化研究的未来发展方向。本文可为无测站流域区域化方法的选择提供基本依据与科学参考。     

Rainfall-runoff modelling of water resources in the upper Senegal River basin

The streamflow series for the upstream basin of the Senegal River is marked by considerable gaps. The objective of this article is to simulate and extend hydrological data, using the GR2M rainfall-runoff model. A sensitivity analysis of the model to rainfall and water holding capacity input data was performed. This analysis was performed after calculating catchment rainfall, mean potential evapotranspiration, and maximum, minimum and mean water holding capacity. The best combination of input data was chosen by catchment based on the Nash-Sutcliffe criterion. Then cross calibration-validation tests were performed, using the selected input data to choose model parameter sets.     

施工导流超标洪水风险率估计的水文模拟方法

利用系统辨识技术，根据实测日径流系列建立了日径流过程的随机模拟模型. 由该模型模拟出多组导流工程服务年限中的日径流过程，经统计得出各种风险率下的设计流量与超标洪水发生次数的关系， 从而把风险率、施工年限、设计流量和超标洪水发生次数紧密联系起来， 为合理选择导流设计流量提供了依据。     

Estimation of geomorphically significant flows in alpine streams of the Rocky Mountains,Colorado (USA)

Streamflows recorded at 24 gauging stations in the Rocky Mountains of Colorado were analyzed to derive regional regression equations for estimating the natural flow duration and flood frequency in reaches where the natural flows are unknown or have been altered by diversion or regulation. The principal objective of this analysis is to determine whether the relatively high, infrequent, but geomorphically and ecologically important flows in the Rocky Mountains can be accurately estimated by regional flow duration equations. The region considered in this study is an area of relatively abundant runoff, and, consequently, intense water resources development. The specific streams analyzed here, however, are unaltered and remain nearly pristine. Regional flow duration equations are derived for two situations. When the mean annual discharge is known, flows ≧10% of the time can be estimated with an uncertainty of ±9% for the 10% exceedance flow, to ±11% for the 1.0% exceedance flow. When the mean annual discharge is unknown, the relatively high, infrequent flow can be estimated using the mean basin precipitation rate (in m³/s), and basin relief with an uncertainty of ±23% for the 10% exceedance flow to ±21% for the 1.0% exeedance flow. The uncertainty in estimated discharges using the equations derived in this analysis is substantially smaller than has been previously reported, especially for the geomorphically significant flows which are relatively large and infrequent. The improvement is due primarily to the quality of streamflow records analyzed and a well‐defined hydrologic region.     

Development of hydrological indices to aid cumulative impact analysis of riverine wetlands

A hydrological analysis of historic stream data collected with the gauge on the Cache River at Patterson, Arkansas, USA, is presented as the basis for cumulative impact analysis of riverine wetlands. Subtle, long-term changes in hydroperiod, which could collectively have major effects on wetland function, are quantified. Harmonic analysis, time-scale analysis, and conventional methods of hydrological analysis of gauge data, at decade intervals, are employed, showing a steady decline in the magnitude and predictability of the baseflow during low flow periods, beginning with the 1920s and becoming increasingly more pronounced into the 1980s. Complementary information suggests that hydroperiod alterations are associated with increased groundwater pumping to support rice agriculture in the basin. These hydrological methods are simple enough for routine application (when adequate data are available) but sufficiently sophisticated to identify subtle changes in hydroperiod associated with cumulative effects. The changes in hydroperiod identified using these methods may have potential to explain changes in biotic communities or wetlands structure as part of comprehensive wetlands studies. © 1997 John Wiley & Sons, Ltd.     

Uncertainty assessment of streamflow projection under the impact of climate change in the Lower Mekong Basin: a case study of the Srepok River Basin,Vietnam

Uncertainty assessment of future projection of streamflow is of the essence for an effective formulation of water resources management and planning adaptive to climate change. The aim of this study is to investigate the uncertainty in streamflow projection under the climate change impact in the Srepok River Basin. Uncertainty associated with emission scenarios (RCP2.6, RCP4.5 and RCP8.5), General Circulation Models (GCMs) (CanESM2, CNMR‐CM5 and HadGEM2‐AO), statistical downscaling methods (delta change method, quantile mapping and SDSM), and hydrological models (ANN, HEC‐HMS and SWAT) is examined. The results showed the largest uncertainty source of the streamflow projection is the GCM simulations, followed by the statistical downscaling methods, hydrological models and emission scenarios. In addition, the use of hydrological models has a considerable impact on uncertainty in the simulations of dry seasonal streamflow. Generally, the present study highlighted the importance of using multi‐GCMs in the studies on hydrological impact of climate change.     

SCS-CN-based Continuous Simulation Model for Hydrologic Forecasting

A new lumped conceptual model based on the Soil Conservation Service Curve Number (SCS-CN) concept has been proposed in this paper for long-term hydrologic simulation and it has been tested using the data of five catchments from different climatic and geographic settings of India. When compared with the Mishra et al. (2005) model based on variable source area (VSA) concept, the proposed model performed better in all applications. Both the models however exhibited a better match between the simulated and observed runoff in high runoff producing watersheds than did in low runoff producing catchments. Using the results of the proposed model, dominant/dormant processes involved in watershed’s runoff generating mechanism have also been identified. The presented model is found useful in the continuous simulation of rainfall–runoff process in watersheds.