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1.
Catchment storage capacity is an important factor in the determination of catchment sensitivity to climate variability. Quantification of catchment sensitivity is in turn important in the regional assessment of the effects of possible climate change. In the present paper, an empirical regional model is proposed that quantifies catchment sensitivity as the ratio of present maximum reservoir storage to catchment storage capacity. Catchment storage capacity is defined theoretically using readily available catchment variables. Present maximum reservoir storage in a catchment, as determined from recession analysis, is expressed as a fraction of catchment storage capacity; the fraction defines catchment sensitivity and depends on storage capacity and annual net precipitation. Average annual conditions for present maximum reservoir storage and average annual net precipitation are used to test the developed model. Although the study used data from only 15 catchments in the Upper Loire region in France, the model proved statistically valid. Storage capacity calculated with the model compares favourably with the baseflow index and a storage index defined in previous research. Values of storage capacity are probable with respect to reported water resources in the area. With the model catchment sensitivity can easily be assessed. Flood or drought prone catchments can be identified as well as a catchment's sensitivity to a catchment-type transition (baseflow versus direct flow dominated catchments). © 1998 John Wiley & Sons, Ltd.  相似文献   

2.
Predicting inter-catchment groundwater flow (IGF) is essential because IGF greatly affects stream water discharge and water chemistry. However, methods for estimating sub-annual IGF and clarifying its mechanisms using minimal data are limited. Thus, we quantified the sub-annual IGF and elucidated its driving factors using the short-term water balance method (STWB) for three forest headwater catchments in Japan (named here catchment A, B and As). Our previous study using the chloride mass balance indicated that annual IGF of catchment A (49.0 ha) can be negligible. Therefore, we calculated the daily evapotranspiration (ET) rate using the Priestley–Taylor expression and the 5-year water balance in catchment A (2010–2014). The sub-annual IGF of the three catchments was then calculated by subtracting the ET rate from the difference between rainfall and stream discharge during the sub-annual water balance periods selected using the STWB. The IGF rates of catchment B (7.0 ha), which is adjacent to catchment A, were positive in most cases, indicating that more groundwater flowed out of the catchment than into it, and exhibited positive linear relationships with rainfall and stream discharge. This suggested that as the catchments became wetter, more groundwater flowed out of catchment B. Conversely, the IGF rates of catchment As (5.3 ha), included in catchment A, were negative in most cases, indicating that more groundwater flowed into the catchment than out from it, and exhibited negative linear relationships with rainfall and stream discharge. Given the topography of the catchments studied, infiltration into the bedrock was the probable reason for the IGF outflow from catchment B. We hypothesized that in catchment As, the discrepancy between the actual hydrological boundary and the surface topographic boundary could have caused an IGF inflow. This study provides a useful tool for determining an IGF model structure to be incorporated into rainfall-runoff models.  相似文献   

3.
Assessing catchment runoff response remains a key research frontier because of limitations in current observational techniques to fully characterize water source areas and transit times in diverse geographical environments. Here, we report a study that combines empirical data with modelling to identify dominant runoff processes in a sparsely monitored humid tropical catchment. The analysis integrated isotope tracers into conceptual rainfall–runoff models of varying complexity (from 5 to 11 calibrated parameters) that are able to simulate discharge and tracer concentrations and track the evolving age of stream water exiting the catchment. The model structures can be seen as competing hypotheses of catchment functioning and were simultaneously calibrated against uncertain streamflow gaugings and a 2‐year daily isotope rainfall–runoff record. Comparison of the models was facilitated using global parameter sensitivity analysis and the resulting effect on calibration. We show that a variety of tested model structures reproduced water and tracer dynamics in stream, but the simpler models failed to adequately reproduce both. The resulting water age distributions of the tested models varied significantly with little similarity between the stream water age and stored water age distributions. The sensitivity analysis revealed that only some of the more complex models (from eight parameters) could be better constrained to infer more plausible water age distributions and catchment storage estimates. These models indicated that the age of water stored in the catchment is generally older compared with the age of water fluxes, with evapotranspiration age being younger compared with streamflow. However, the water age distributions followed a similar temporal behaviour dominated by climatic seasonality. Stream water ages increased during the dry season (greater than 1 year) and decreased with increased streamflow (a few weeks old) during the wet season. We further show that the ratios of the streamwater age to stored water age distribution and the water age distribution of actual evapotranspiration to the stored water age distribution from constrained models could potentially serve as useful hydrological indicators of catchment functioning. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

4.
Diagnostic analyses of hydrological models intend to improve the understanding of how processes and their dynamics are represented in models. Temporal patterns of parameter dominance could be precisely characterized with a temporally resolved parameter sensitivity analysis. In this way, the discharge conditions are characterized, that lead to a parameter dominance in the model. To achieve this, the analysis of temporal dynamics in parameter sensitivity is enhanced by including additional information in a three‐tiered framework on different aggregation levels. Firstly, temporal dynamics of parameter sensitivity provide daily time series of their sensitivities to detect variations in the dominance of model parameters. Secondly, the daily sensitivities are related to the flow duration curve (FDC) to emphasize high sensitivities of model parameters in relation to specific discharge magnitudes. Thirdly, parameter sensitivities are monthly averaged separately for five segments of the FDC to detect typical patterns of parameter dominances for different discharge magnitudes. The three methodical steps are applied on two contrasting catchments (upland and lowland catchment) to demonstrate how the temporal patterns of parameter dynamics represent different hydrological regimes. The discharge dynamic in the lowland catchment is controlled by groundwater parameters for all discharge magnitudes. In contrast, different processes are relevant in the upland catchment, because the dominances of parameters from fast and slow runoff components in the upland catchment are changing over the year for the different discharge magnitudes. The joined interpretation of these three diagnostic steps provides deeper insights of how model parameters represent hydrological dynamics in models for different discharge magnitudes. Thus, this diagnostic framework leads to a better characterization of model parameters and their temporal dynamics and helps to understand the process behaviour in hydrological models. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

5.
The active rock glacier “Innere Ölgrube” and its catchment area (Ötztal Alps, Austria) are assessed using various hydro(geo)logical tools to provide a thorough catchment characterization and to quantify temporal variations in recharge and discharge components. During the period from June 2014 to July 2018, an average contribution derived from snowmelt, ice melt and rainfall of 35.8%, 27.6% and 36.6%, respectively, is modelled for the catchment using a rainfall-runoff model. Discharge components of the rock glacier springs are distinguished using isotopic data as well as other natural and artificial tracer data, when considering the potential sources rainfall, snowmelt, ice melt and longer stored groundwater. Seasonal as well as diurnal variations in runoff are quantified and the importance of shallow groundwater within this rock glacier-influenced catchment is emphasized. Water derived from ice melt is suggested to be provided mainly by melting of two small cirque glaciers within the catchment and subordinately by melting of permafrost ice of the rock glacier. The active rock glacier is characterized by a layered internal structure with an unfrozen base layer responsible for groundwater storage and retarded runoff, a main permafrost body contributing little to the discharge (at the moment) by permafrost thaw and an active layer responsible for fast lateral flow on top of the permafrost body. Snowmelt contributes at least 1/3rd of the annual recharge. During droughts, meltwater derived from two cirque glaciers provides runoff with diurnal runoff variations; however, this discharge pattern will change as these cirque glaciers will ultimately disappear in the future. The storage-discharge characteristics of the investigated active rock glacier catchment are an example of a shallow groundwater aquifer in alpine catchments that ought to be considered when analysing (future) river runoff characteristics in alpine catchments as these provide retarded runoff during periods with little or no recharge.  相似文献   

6.
Testing competing conceptual model hypotheses in hydrology is complicated by uncertainties from a wide range of sources, which result in multiple simulations that explain catchment behaviour. In this study, the limits of acceptability uncertainty analysis approach used to discriminate between 78 competing hypotheses in the Framework for Understanding Structural Errors for 24 catchments in the UK. During model evaluation, we test the model's ability to represent observed catchment dynamics and processes by defining key hydrologic signatures and time step‐based metrics from the observed discharge time series. We explicitly account for uncertainty in the evaluation data by constructing uncertainty bounds from errors in the stage‐discharge rating curve relationship. Our study revealed large differences in model performance both between catchments and depending on the type of diagnostic used to constrain the simulations. Model performance varied with catchment characteristics and was best in wet catchments with a simple rainfall‐runoff relationship. The analysis showed that the value of different diagnostics in constraining catchment response and discriminating between competing conceptual hypotheses varies according to catchment characteristics. The information content held within water balance signatures was found to better capture catchment dynamics in chalk catchments, where catchment behaviour is predominantly controlled by seasonal and annual changes in rainfall, whereas the information content in the flow‐duration curve and time‐step performance metrics was able to better capture the dynamics of rainfall‐driven catchments. We also investigate the effect of model structure on model performance and demonstrate its (in)significance in reproducing catchment dynamics for different catchments. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

7.
Recent studies have shown that boreal peatlands exhibit considerable chemical variability but without clear spatial pattern. This chemical heterogeneity illustrates the complex hydrological behaviour of peatlands, particularly patterned fen. Isotopic, chemical and physical tracers were used to describe the hydrological behaviour of a small boreal headwater catchment (13 ha) during the snow‐free period with a special emphasis on the downstream patterned fen. Results showed that shallow pools were mixed every day during the summer, particularly during nights or discharge periods. Despite large water storage capacities in pools, which should induce large buffer effect, hydrological behaviour of patterned fen is more similar to a piston flow process. This is probably because of the division of the fen into successive small cascading streamflow reservoirs. The consequences were a rapid change of the chemical signature throughout the fen, particularly upstream. A spatial pattern was observed downstream in early summer. The isotopic signature passed from an upstream depleted and homogeneous signature to a progressively enriched downstream signature. However, this pattern was not identified during the wetter period (late summer), probably because the discharge, which dominated the water budget, decreased the surface water residence time and flushed a large proportion of stored surface water. We developed for this patterned fen a conceptual model of the surface flow to explain these particular mixing effects and the implications on the dynamics of the chemical signature. To further our understanding of similar boreal headwater catchments, future work should include the development of a multiple mixed‐reservoir model. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

8.
Streamflow response of Belgian catchments to IPCC climate change scenarios   总被引：8，自引：0，他引：8  
The IRMB (Integrated Runoff Model—F. Bultot) daily step conceptual model has been applied to eight Belgian catchments with areas ranging from 100 to 1200 km2. These catchments are characterized by various infiltration rates and ground water storage capacities. The outputs of six GCMs (General Circulation Model) distributed by the IPCC (Intergovernmental Panel on Climate Change) and an earlier scenario have been used to perturb time series of hydrometeorological input data relevant to simulate the water cycle. This paper focuses on the impacts on streamflow and its surface and underground components, as well as on the occurrence of flood days and low flow days. Impacts are shown to be catchment and scenario dependent. Due to the scenario diversity, streamflow impacts are found to be either positive or negative. The trends are common to scenarios with the same patterns or to catchments with similar characteristics. For all but two scenarios, all the catchments present an increase of flood frequency. Nevertheless, for all the scenarios, catchments with prevailing surface flow are undergoing an increase in flood frequency during winter months.  相似文献   

9.
Our work analyses the intra‐annual variability of the volume of water stored in 15 forested headwater catchments from south‐central Chile, aiming at understanding how forest management, hydrology, and climate influence the dynamic components of catchment storage. Thus, we address the following questions: (a) How does the annual water storage vary in catchments located in diverse hydroclimatic conditions and subject to variable forest management? (b) Which natural (i.e., hydrologic regime and physiographic setting) and anthropogenic factors explain the variance in water storage? Results show that the annual catchment storage increases at the beginning of each hydrological year in direct response to increases in rainfall. The maximum water storage ranges from 666 to 1,272 mm in these catchments. The catchments with Pinus or Eucalyptus spp. cover store less water than the catchments with mixed forest species cover. Forest cover (biomass volume, plantation density, and percentage of plantation and age) has the primary control on dynamic storage in all catchments. These results indicate that forest management may alter the catchment water storage.  相似文献   

10.
There is considerable interest in large‐scale spatial patterns of sediment transport in catchments, and this topic is often approached using terrain‐based modelling. In such models topography influences the discharge of overland flow and its sediment transport capacity. The sediment transport capacity of overland flow is commonly expressed as a power function of slope and discharge (i.e. qs=k1qβSγ). The relationship between discharge and contributing area can also be expressed as a power function. Several reviews reveal a limited range of values for the two exponents β and γ. In this paper we examine the sensitivity of catchment‐scale patterns of sediment delivery to valley floors to a range of sediment transport capacity and hillslope hydrology parameterizations, using two catchments on the southern tablelands of New South Wales. The results indicate that, over the limited range of β and γ identified within the literature, sediment deliveries to valley floors across the two catchments are similar for all but one of five sediment transport capacity relationships. The patterns are dominated by the trend in slope through each catchment. The sensitivity to hillslope hydrology of predicted sediment delivery patterns is strong in the catchment with systematic variation in unit hillslope area, and weak in the catchment for which there are no systematic trends in unit hillslope area. We believe there is less experimental evidence to restrict choice of hillslope hydrology parameters than there is for sediment transport capacity. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

11.
Hydrological classification systems seek to provide information about the dominant processes in the catchment to enable information to be transferred between catchments. Currently, there is no widely agreed‐upon system for classifying river catchments. This paper develops a novel approach to classifying catchments based on the temporal dependence structure of daily mean river flow time series, applied to 116 near‐natural ‘benchmark’ catchments in the UK. The classification system is validated using 49 independent catchments. Temporal dependence in river flow data is driven by the flow pathways, connectivity and storage within the catchment and can thus be used to assess the influence catchment characteristics have on moderating the precipitation‐to‐flow relationship. Semi‐variograms were computed for the 116 benchmark catchments to provide a robust and efficient way of characterising temporal dependence. Cluster analysis was performed on the semi‐variograms, resulting in four distinct clusters. The influence of a wide range of catchment characteristics on the semi‐variogram shape was investigated, including: elevation, land cover, physiographic characteristics, soil type and geology. Geology, depth to gleyed layer in soils, slope of the catchment and the percentage of arable land were significantly different between the clusters. These characteristics drive the temporal dependence structure by influencing the rate at which water moves through the catchment and/or the storage in the catchment. Quadratic discriminant analysis was used to show that a model with five catchment characteristics is able to predict the temporal dependence structure for un‐gauged catchments. This method could form the basis for future regionalisation strategies, as a way of transferring information on the precipitation‐to‐flow relationship between gauged and un‐gauged catchments. © 2014 The Authors. Hydrological Processes by published by John Wiley & Sons, Ltd.  相似文献   

12.
Fine sediment delivery to and storage in stream channel reaches can disrupt aquatic habitats, impact river hydromorphology, and transfer adsorbed nutrients and pollutants from catchment slopes to the fluvial system. This paper presents a modelling tool for simulating the time‐dependent response of the fine sediment system in catchments, using an integrated approach that incorporates both land phase and in‐stream processes of sediment generation, storage and transfer. The performance of the model is demonstrated by applying it to simulate in‐stream suspended sediment concentrations in two lowland catchments in southern England, the Enborne and the Lambourn, which exhibit contrasting hydrological and sediment responses due to differences in substrate permeability. The sediment model performs well in the Enborne catchment, where direct runoff events are frequent and peak suspended sediment concentrations can exceed 600 mg l?1. The general trends in the in‐stream concentrations in the Lambourn catchment are also reproduced by the model, although the observed concentrations are low (rarely exceeding 50 mg l?1) and the background variability in the concentrations is not fully characterized by the model. Direct runoff events are rare in this highly permeable catchment, resulting in a weak coupling between the sediment delivery system and the catchment hydrology. The generic performance of the model is also assessed using a generalized sensitivity analysis based on the parameter bounds identified in the catchment applications. Results indicate that the hydrological parameters contributing to the sediment response include those controlling (1) the partitioning of runoff between surface and soil zone flows and (2) the fractional loss of direct runoff volume prior to channel delivery. The principal sediment processes controlling model behaviour in the simulations are the transport capacity of direct runoff and the in‐stream generation, storage and release of the fine sediment fraction. The in‐stream processes appear to be important in maintaining the suspended sediment concentrations during low flows in the River Enborne and throughout much of the year in the River Lambourn. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

13.
The estimation of catchment‐scale soil properties, such as water storage capacity and hydraulic conductivity, is of primary interest for the implementation of distributed hydrological models at the regional scale. This estimation is generally performed on the basis of information provided by soil databases. However, such databases are often established for agronomic uses and generally do not document deep‐weathered rock horizons (i.e. pedologic horizons of type C and deeper), which can play a major role in water transfer and storages. Here, we define the Drainable Storage Capacity Index (DSCI), an indicator that relies on the comparison between cumulated streamflow and precipitation to assess catchment‐scale storage capacities. DSCI is found to be reliable to detect underestimation of soil storage capacities in soil databases. We also use the streamflow recession analysis methodology defined by Brutsaert and Nieber in 1977 to estimate water storage capacities and lateral saturated hydraulic conductivities of the nondocumented deep horizons. The analysis is applied to a sample of 23 catchments (0.2–291 km2) located in the Cévennes‐Vivarais region (south of France). For regionalization purposes, the obtained results are compared with the dominant catchment geology and present a clear hierarchy between the different geologies of the area. Hard crystalline rocks are found to be associated with the thickest and less conductive deep soil horizons. Schist rocks present intermediate values of thickness and of saturated hydraulic conductivity, whereas sedimentary rocks and alluvium are found to be less thick and most conductive. These results are of primary interest in view of the future set‐up of distributed hydrological models over the Cévennes‐Vivarais region. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

14.
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15.
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16.
太湖西苕溪流域径流过程的模拟   总被引：5，自引：1，他引：4  
张奇  李恒鹏  徐力刚 《湖泊科学》2006,18(4):401-406
西苕溪是太湖集水域的一个主要流域,研究西苕溪流域径流过程及污染物产出对了解太湖水文水质变化以及开展周围其它流域研究工作具有重要意义．作为研究的第一步,采用集总式模型LASCAM建立了西苕溪流域径流模型．以流域内2个水文观测站1968-1988年日径流观测数据对模型作了率定．率定效果满意,模拟日、年径流量与观测值吻合良好．在流域资料不够充分的情况下,模型能获得较为理想的模拟效果,说明所采用的模型适用于数据不足区域．模拟还揭示,西苕溪流域径流产生可能以饱和地面径流机制为主．近河道浅层饱和土体的水位与降雨量相关性好,呈现出明显的日波动周期;而深层地下水位呈年波动周期,在旱季和雨季,水位呈明显的降落和上升趋势．这些发现为进一步细化径流模型以及建立污染物输移模型奠定了基础．  相似文献   

17.
Hydrological models used for flood prediction in ungauged catchments are commonly fitted to regionally transferred data. The key issue of this procedure is to identify hydrologically similar catchments. Therefore, the dominant controls for the process of interest have to be known. In this study, we applied a new machine learning based approach to identify the catchment characteristics that can be used to identify the active processes controlling runoff dynamics. A random forest (RF) regressor has been trained to estimate the drainage velocity parameters of a geomorphologic instantaneous unit hydrograph (GIUH) in ungauged catchments, based on regionally available data. We analyzed the learning procedure of the algorithm and identified preferred donor catchments for each ungauged catchment. Based on the obtained machine learning results from catchment grouping, a classification scheme for drainage network characteristics has been derived. This classification scheme has been applied in a flood forecasting case study. The results demonstrate that the RF could be trained properly with the selected donor catchments to successfully estimate the required GIUH parameters. Moreover, our results showed that drainage network characteristics can be used to identify the influence of geomorphological dispersion on the dynamics of catchment response.  相似文献   

18.
The higher mid‐latitudes of the Northern Hemisphere are particularly sensitive to climate change as small differences in temperature determine frozen ground status, precipitation phase, and the magnitude and timing of snow accumulation and melt. An international inter‐catchment comparison program, North‐Watch, seeks to improve our understanding of the sensitivity of northern catchments to climate change by examining their hydrological and biogeochemical responses. The catchments are located in Sweden (Krycklan), Scotland (Mharcaidh, Girnock and Strontian), the United States (Sleepers River, Hubbard Brook and HJ Andrews) and Canada (Catamaran, Dorset and Wolf Creek). This briefing presents the initial stage of the North‐Watch program, which focuses on how these catchments collect, store and release water and identify ‘types’ of hydro‐climatic catchment response. At most sites, a 10‐year data of daily precipitation, discharge and temperature were compiled and evaporation and storage were calculated. Inter‐annual and seasonal patterns of hydrological processes were assessed via normalized fluxes and standard flow metrics. At the annual‐scale, relations between temperature, precipitation and discharge were compared, highlighting the role of seasonality, wetness and snow/frozen ground. The seasonal pattern and synchronicity of fluxes at the monthly scale provided insight into system memory and the role of storage. We identified types of catchments that rapidly translate precipitation into runoff and others that more readily store water for delayed release. Synchronicity and variance of rainfall–runoff patterns were characterized by the coefficient of variation (cv) of monthly fluxes and correlation coefficients. Principal component analysis (PCA) revealed clustering among like catchments in terms of functioning, largely controlled by two components that (i) reflect temperature and precipitation gradients and the correlation of monthly precipitation and discharge and (ii) the seasonality of precipitation and storage. By advancing the ecological concepts of resistance and resilience for catchment functioning, results provided a conceptual framework for understanding susceptibility to hydrological change across northern catchments. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

19.
Nearby catchments in the same landscape are often assumed to have similar specific discharge (runoff per unit catchment area). Five years of streamflow from 14 nested catchments in a 68 km2 landscape was used to test this assumption, with the hypothesis that the spatial variability in specific discharge is smaller than the uncertainties in the measurement. The median spatial variability of specific discharge, defined as subcatchment deviation from the catchment outlet, was 33% at the daily scale. This declined to 24% at a monthly scale and 19% at an annual scale. These specific discharge differences are on the same order of magnitude as predicted for major land‐use conversions or a century of climate change. Spatial variability remained when considering uncertainties in specific discharge, and systematic seasonal patterns in specific discharge variation further provide confidence that these differences are more than just errors in the analysis of catchment area, rainfall variability or gauging. Assuming similar specific discharge in nearby catchments can thus lead to spurious conclusions about the effects of disturbance on hydrological and biogeochemical processes. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

20.
The period of direct groundwater storage measurements is often too short to allow reliable inferences of groundwater storage trends at catchment scales. However, as groundwater storage sustains low flows in catchments during dry periods, groundwater storage can also be estimated indirectly from daily streamflow based on hydraulic groundwater theory; this idea was applied herein to 17 selected Australian catchments to examine their long-term (half a century or longer) groundwater storage trends. On average, over past 45 years, groundwater storage exhibited negative trends in all the selected catchments, except in the Katherine River catchment located in the Northern Territory. These negative trends persisted over longer periods, close to 100 years in some catchments and the strongest decreasing trend of 0.241 mm per year was observed in the Barron River catchment in New South Wales. However, groundwater storage exhibited different trends over the different shorter periods. Thus, while during the period of 1997–2007, 15 out of the 17 catchments showed negative trends in groundwater storage, during the period of 1980–2000, 12 out of the 17 catchments exhibited positive trends in groundwater storage; this underscores the fact that record lengths of one or even two decades are inadequate to derive meaningful trends. Strong consistencies in the trends exist across most catchments, indicating that groundwater storage is affected by large-scale climate factors.  相似文献   

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