| 1. |
|
|
| 2. |
- Ali, Genevieve, et al.
(författare)
-
Comparison of threshold hydrologic response across northern catchments
- 2015
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 29:16, s. 3575-3591
-
Tidskriftsartikel (refereegranskat)abstract
- Nine mid-latitude to high-latitude headwater catchments - part of the Northern Watershed Ecosystem Response to Climate Change (North-Watch) programme - were used to analyze threshold response to rainfall and snowmelt-driven events and link the different responses to the catchment characteristics of the nine sites. The North-Watch data include daily time-series of various lengths of multiple variables such as air temperature, precipitation and discharge. Rainfall and meltwater inputs were differentiated using a degree-day snowmelt approach. Distinct hydrological events were identified, and precipitation-runoff response curves were visually assessed. Results showed that eight of nine catchments showed runoff initiation thresholds and effective precipitation input thresholds. For rainfall-triggered events, catchment hydroclimatic and physical characteristics (e.g. mean annual air temperature, median flow path distance to the stream, median sub-catchment area) were strong predictors of threshold strength. For snowmelt-driven events, however, thresholds and the factors controlling precipitation-runoff response were difficult to identify. The variability in catchments responses to snowmelt was not fully explained by runoff initiation thresholds and input magnitude thresholds. The quantification of input intensity thresholds (e.g. snow melting and permafrost thawing rates) is likely required for an adequate characterization of nonlinear spring runoff generation in such northern environments.
|
|
| 3. |
- Ameli, A. A., et al.
(författare)
-
The exponential decline in saturated hydraulic conductivity with depth : a novel method for exploring its effect on water flow paths and transit time distribution
- 2016
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 30:14, s. 2438-2450
-
Tidskriftsartikel (refereegranskat)abstract
- The strong vertical gradient in soil and subsoil saturated hydraulic conductivity is characteristic feature of the hydrology of catchments. Despite the potential importance of these strong gradients, they have proven difficult to model using robust physically based schemes. This has hampered the testing of hypotheses about the implications of such vertical gradients for subsurface flow paths, residence times and transit time distribution. Here we present a general semi-analytical solution for the simulation of 2D steady-state saturated-unsaturated flow in hillslopes with saturated hydraulic conductivity that declines exponentially with depth. The grid-free solution satisfies mass balance exactly over the entire saturated and unsaturated zones. The new method provides continuous solutions for head, flow and velocity in both saturated and unsaturated zones without any interpolation process as is common in discrete numerical schemes. This solution efficiently generates flow pathlines and transit time distributions in hillslopes with the assumption of depth-varying saturated hydraulic conductivity. The model outputs reveal the pronounced effect that changing the strength of the exponential decline in saturated hydraulic conductivity has on the flow pathlines, residence time and transit time distribution. This new steady-state model may be useful to others for posing hypotheses about how different depth functions for hydraulic conductivity influence catchment hydrological response.
|
|
| 4. |
- Amvrosiadi, Nino, et al.
(författare)
-
Water storage dynamics in a till hillslope : the foundation for modeling flows and turnover times
- 2017
-
Ingår i: Hydrological Processes. - : John Wiley and Sons Ltd. - 0885-6087 .- 1099-1085. ; 31:1, s. 4-14
-
Tidskriftsartikel (refereegranskat)abstract
- Studies on hydrology, biogeochemistry, or mineral weathering often rely on assumptions about flow paths, water storage dynamics, and transit times. Testing these assumptions requires detailed hydrometric data that are usually unavailable at the catchment scale. Hillslope studies provide an alternative for obtaining a better understanding, but even on such well-defined and delimited scales, it is rare to have a comprehensive set of hydrometric observations from the water divide down to the stream that can constrain efforts to quantify water storage, movement, and turnover time. Here, we quantified water storage with daily resolution in a hillslope during the course of almost an entire year using hydrological measurements at the study site and an extended version of the vertical equilibrium model. We used an exponential function to simulate the relationship between hillslope discharge and water table; this was used to derive transmissivity profiles along the hillslope and map mean pore water velocities in the saturated zone. Based on the transmissivity profiles, the soil layer transmitting 99% of lateral flow to the stream had a depth that ranged from 8.9 m at the water divide to under 1 m closer to the stream. During the study period, the total storage of this layer varied from 1189 to 1485 mm, resulting in a turnover time of 2172 days. From the pore water velocities, we mapped the time it would take a water particle situated at any point of the saturated zone anywhere along the hillslope to exit as runoff. Our calculations point to the strengths as well as limitations of simple hydrometric data for inferring hydrological properties and water travel times in the subsurface.
|
|
| 5. |
- Andersson, Jan-Olov, 1966-, et al.
(författare)
-
Spatial variation of wetlands and flux of dissolved organic carbon in boreal headwater streams
- 2008
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; :22, s. 1965-1975
-
Tidskriftsartikel (refereegranskat)abstract
- In order to investigate the relation between water chemistry and functional landscape elements, spatial data sets of characteristics for 68 small (0·2–1·5 km2) boreal forest catchments in western central Sweden were analysed in a geographical information system (GIS). The geographic data used were extracted from official topographic maps. Water sampled four times at different flow situations was analysed chemically. This paper focuses on one phenomenon that has an important influence on headwater quality in boreal, coniferous forest streams: generation and export of dissolved organic carbon (DOC). It is known that wetland cover (bogs and fens) in the catchment is a major source of DOC. In this study, a comparison was made between a large number of headwater catchments with varying spatial locations and areas of wetlands. How this variation, together with a number of other spatial variables, influences the DOC flux in the streamwater was analysed by statistical methods. There were significant, but not strong, correlations between the total percentages of wetland area and DOC flux measured at a medium flow situation, but not at high flow. Neither were there any significant correlations between the percentage of wetland area connected to streams, nor the percentage of wetland area within a zone 50 m from the stream and the DOC flux. There were, however, correlations between catchment mean slope and the DOC flux in all but one flow situations. This study showed that, considering geographical data retrieved from official sources, the topography of a catchment better explains the variation in DOC flux than the percentage and locations of distinct wetland areas. This emphasizes the need for high-resolution elevation models accurate enough to reveal the sources of DOC found in headwater streams.
|
|
| 6. |
|
|
| 7. |
- Asokan, Shilpa M., 1979-, et al.
(författare)
-
Analysis of water resources in the Mahanadi River Basin, India under projected climate conditions
- 2008
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 22:18, s. 3589-3603
-
Tidskriftsartikel (refereegranskat)abstract
- The paper presents the outcomes of a study conducted to analyse water resources availability and demand in the Mahanadi River Basin in India under climate change conditions. Climate change impact analysis was carried out for the years 2000, 2025, 2050, 2075 and 2100, for the months of September and April (representing wet and dry months), at a sub-catchment level. A physically based distributed hydrologic model (DHM) was used for estimation of the present water availability. For future scenarios under climate change conditions, precipitation output of Canadian Centre for Climate Modelling and Analysis General Circulation Model (CGCM2) was used as the input data for the DHM. The model results show that the highest increase in peak runoff (38%) in the Mahanadi River outlet will occur during September, for the period 2075-2100 and the maximum decrease in average runoff (32·5%) will be in April, for the period 2050-2075. The outcomes indicate that the Mahanadi River Basin is expected to experience progressively increasing intensities of flood in September and drought in April over the considered years. The sectors of domestic, irrigation and industry were considered for water demand estimation. The outcomes of the analysis on present water use indicated a high water abstraction by the irrigation sector. Future water demand shows an increasing trend until 2050, beyond which the demand will decrease owing to the assumed regulation of population explosion. From the simulated future water availability and projected water demand, water stress was computed. Among the six sub-catchments, the sub-catchment six shows the peak water demand. This study hence emphasizes on the need for re-defining water management policies, by incorporating hydrological response of the basin to the long-term climate change, which will help in developing appropriate flood and drought mitigation measures at the basin level.
|
|
| 8. |
- Barron, Jennie
(författare)
-
Establishing irrigation potential of a hillside aquifer in the African highlands
- 2020
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 34, s. 1741-1753
-
Tidskriftsartikel (refereegranskat)abstract
- Feeding 9 billion people in 2050 will require sustainable development of all water resources, both surface and subsurface. Yet, little is known about the irrigation potential of hillside shallow aquifers in many highland settings in sub-Saharan Africa that are being considered for providing irrigation water during the dry monsoon phase for smallholder farmers. Information on the shallow groundwater being available in space and time on sloping lands might aid in increasing food production in the dry monsoon phase. Therefore, the research objective of this work is to estimate potential groundwater storage as a potential source of irrigation water for hillside aquifers where lateral subsurface flow is dominant. The research was carried out in the Robit Bata experimental watershed in the Lake Tana basin which is typical of many undulating watersheds in the Ethiopian highlands. Farmers have excavated more than 300 hand dug wells for irrigation. We used 42 of these wells to monitor water table fluctuation from April 16, 2014 to December 2015. Precipitation and runoff data were recorded for the same period. The temporal groundwater storage was estimated using two methods: one based on the water balance with rainfall as input and baseflow and evaporative losses leaving the watershed as outputs; the second based on the observed rise and fall of water levels in wells. We found that maximum groundwater storage was at the end of the rain phase in September after which it decreased linearly until the middle of December due to short groundwater retention times. In the remaining part of the dry season period, only wells located close to faults contained water. Thus, without additional water sources, sloping lands can only be used for significant irrigation inputs during the first 3 months out of the 8 months long dry season.
|
|
| 9. |
- Beldring, S, et al.
(författare)
-
Kinematic wave approximations to hillslope hydrological processes in tills
- 2000
-
Ingår i: HYDROLOGICAL PROCESSES. - : JOHN WILEY & SONS LTD. - 0885-6087. ; 14:4, s. 727-745
-
Tidskriftsartikel (refereegranskat)abstract
- This work has been carried out within the framework of NOPEX - a NOrthern hemisphere climate Processes land surface EXperiment. Its purpose is to describe the spatial variability of groundwater levels and soil moisture content and their influence on runof
|
|
| 10. |
- Beldring, Stein, et al.
(författare)
-
Kinematic wave approximations to hillslope hydrological processes in tills
- 2000
-
Ingår i: Hydrological Processes. - 0885-6087 .- 1099-1085. ; 14:4, s. 727-745
-
Tidskriftsartikel (refereegranskat)abstract
- This work has been carried out within the framework of NOPEX - a NOrthern hemisphere climate Processes land surface EXperiment. Its purpose is to describe the spatial variability of groundwater levels and soil moisture content and their influence on runoff generation in small catchments in a landscape dominated by boreal forest and till soils, which is characteristic for the Nordic countries. Kinematic wave approximations have been used to describe saturated subsurface flow and saturation overland flow in hillslopes with a thin soil layer overlying a relatively impermeable bedrock. Simultaneous analyses of catchment runoff, groundwater-table depths and soil moisture in the unsaturated zone have been performed by including the kinematic wave descriptions in a precipitation-runoff model. The results have been compared with observed hydrographs and spatial patterns of groundwater levels and soil moisture content in two small experimental catchments. Results from this study indicate that is reasonable to apply the same parameter set when describing hydrological processes in computational elements with similar characteristics at a scale of about 1 km(2) in the NOPEX area.
|
|
| 11. |
- Bengtsson, Lars, et al.
(författare)
-
Extreme storms in Malmo, Sweden
- 2010
-
Ingår i: Hydrological Processes. - : Wiley. - 1099-1085 .- 0885-6087. ; 24:24, s. 3462-3475
-
Tidskriftsartikel (refereegranskat)abstract
- Short-term very intensive storms in the years 1980-2007 from rain gauges in Malmo have been analysed to find intensities of long return periods and to investigate trends. Observations from different stations have been pooled into series to which probability functions have been adjusted. Quality control of short-term precipitation records is emphasized. In order to investigate whether high rain intensities are different today compared to back in time, new and old rain data have been compared. Trends over the last 25 years have been computed for storms of duration 10 min to 1 h, and for 89 years of daily rains. A literature review of investigations of changing rain intensities is presented. It is found that 10- to 25-year long rain series from single stations are too short to give good estimates of storms of long recurrence time because a single event influences much. The largest observed rains in Malmo in the investigated period have a return period of about 20-50 years. For the very short-term storms, 50-year old intensity-duration-frequency curves do not differ much from those derived from new data. Trend analysis shows changing short-term high storm intensities only for storms of 10-min duration. (C) Copyright. 2010 John Wiley & Sons, Ltd.
|
|
| 12. |
|
|
| 13. |
- Bengtsson, Lars, et al.
(författare)
-
Long- term change of daily and multi- daily precipitation in southern Sweden
- 2014
-
Ingår i: Hydrological Processes. - : Wiley. - 1099-1085 .- 0885-6087. ; 28:6, s. 2897-2911
-
Tidskriftsartikel (refereegranskat)abstract
- Daily rain series from southern Sweden with records dating back to the 1870s have been analysed to investigate the trends of daily and multi-day precipitation of different return periods with emphasis on the extremes. Probabilities of extreme storms were determined as continuously changing values based on 25 years of data. An extra set of data was used to investigate changes in Skane, the southernmost peninsula of Sweden. Another 30-year data set of more than 200 stations of a dense gauge network in Skane was used to investigate the relation between very large daily rainfall and annual precipitation. The annual precipitation has increased significantly all over southern Sweden due to increased winter precipitation. There is a trend of increasing maximum annual daily precipitation at only one station, where the annual maximum often occurs in winter. The number of events with a short return period is increasing, but the number of more extreme events has not increased. Daily and multi-daily design storms of long return periods determined from extreme value analysis with updating year by year are not higher today than during the last 100 years. The largest daily storms are not related to stations with annual rainfall but seem to occur randomly. Copyright (c) 2013 John Wiley & Sons, Ltd.
|
|
| 14. |
- Bengtsson, Lars
(författare)
-
Probability of combined high sea levels and large rains in Malmö, Sweden, southern Öresund
- 2016
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087. ; 30:18, s. 3172-3183
-
Tidskriftsartikel (refereegranskat)abstract
- Observations of sea level and precipitation in Malmö, Sweden in the southeastern part of the sound Öresund have been used to estimate the probabilities of local compound events of high sea level and large daily and hourly rains. There are observations of sea level and daily rains extending back to 1930. The observations of short-term rainfall are from 1980 and onwards. Most large rainfalls come in the summer, while the highest sea levels are in the autumn and in the winter. The highest observed sea level is about 130cm above mean sea level, and the largest daily rain is close to 100mm. However, the highest sea level observed during a day with rainfall corresponding to the 1-year rain is less than 60cm. The highest sea level observed during an hour with 1-year hourly rainfall is 30cm. From the statistics of daily rains, hourly rains and sea level, extreme values for each of them have been computed. For events with frequency higher than one per four years the probabilities of combined events sea level - rainfall are determined directly from the observations. For more rare events, marginal distributions of sea level and rainfall are determined. Copulas and conditional probabilities are used. When the sea level exceeds 20cm above mean sea level, daily rains exceeding 10mm are almost independent of the sea level and so are hourly rains exceeding 5mm. It is extremely rare that large rains occur when the sea level is very high. The combination of 1-year rainfall and the 1-year sea level has a return period of more than 200years.
|
|
| 15. |
|
|
| 16. |
- Beven, Keith
(författare)
-
Advice to a young hydrologist
- 2016
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 30:20, s. 3578-3582
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 17. |
|
|
| 18. |
- Beven, Keith J., et al.
(författare)
-
GLUE : 20 years on
- 2014
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 28:24, s. 5897-5918
-
Forskningsöversikt (refereegranskat)abstract
- This paper reviews the use of the Generalized Likelihood Uncertainty Estimation (GLUE) methodology in the 20 years since the paper by Beven and Binley in Hydrological Processes in (1992), which is now one of the most highly cited papers in hydrology. The original conception, the on-going controversy it has generated, the nature of different sources of uncertainty and the meaning of the GLUE prediction uncertainty bounds are discussed. The hydrological, rather than statistical, arguments about the nature of model and data errors and uncertainties that are the basis for GLUE are emphasized. The application of the Institute of Hydrology distributed model to the Gwy catchment at Plynlimon presented in the original paper is revisited, using a larger sample of models, a wider range of likelihood evaluations and new visualization techniques. It is concluded that there are good reasons to reject this model for that data set. This is a positive result in a research environment in that it requires improved models or data to be made available. In practice, there may be ethical issues of using outputs from models for which there is evidence for model rejection in decision making. Finally, some suggestions for what is needed in the next 20 years are provided.
|
|
| 19. |
- Beven, Keith
(författare)
-
On doing better hydrological science
- 2008
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 22:17, s. 3549-3553
-
Tidskriftsartikel (refereegranskat)
|
|
| 20. |
|
|
| 21. |
- Beven, Keith
(författare)
-
On undermining the science?
- 2006
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 20:14, s. 3141-3146
-
Tidskriftsartikel (refereegranskat)
|
|
| 22. |
|
|
| 23. |
- Beven, Keith
(författare)
-
Preferential flows and travel time distributions : defining adequate hypothesis tests for hydrological process models
- 2010
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 24:12, s. 1537-1547
-
Tidskriftsartikel (refereegranskat)abstract
- This introduction to the second annual review issue of Hydrological Processes tries to put the collection of papers on preferential flows and travel time distributions into a more general context of testing models as hypotheses about how catchment systems function. It is suggested that, because of the possibilities of non-stationary and epistemic errors in both data and models, such tests could be carried out within a rejectionist limits-of-acceptability framework. The principles and difficulties of hypothesis testing within these particular research areas are discussed. An important point to take from this discussion is that the use of a formal testing framework, and the consequent rejection of models as hypotheses after allowing for uncertainties in the data, is the starting point for developing better theories and data sets. Copyright (C) 2010 John Wiley & Sons, Ltd.
|
|
| 24. |
|
|
| 25. |
- Beven, Keith, et al.
(författare)
-
Velocities, celerities and the basin of attraction in catchment response
- 2015
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 29:25, s. 5214-5226
-
Tidskriftsartikel (refereegranskat)abstract
- Catchment systems are interestingly nonlinear, but their dynamics are constrained from being unduly chaotic by mass and energy balance requirements. There have been no attempts in hydrology that we know of that have tried to map both the flow and transport dynamics of a catchment in any form of phase space. In part, this is because of the high dimensionality of the space-time patterns of response; in part because there is sufficient uncertainty about the input and output fluxes estimated by measurement that this might be expected to obscure any attractor-like behaviour. In this study we explore the basin of the catchment attractor for the Multiple Interacting Pathway (MIPs) model that in previous papers has been shown to give good results for the small Gardsjon catchment in Sweden. MIPs is based on particle tracking techniques and gives results for both the flow responses and for the travel and residence time responses of water in the catchment. Here it is used to provide consistent values of fluxes, total storage, travel time distributions and residence time distributions for a long simulation period. The nature of those responses in storage and input dimensions is then investigated. The results suggest that the range of behaviours is hysteretic in interesting ways and constrained by the forcing inputs, with space filling of trajectories in the basin of attraction as should be expected of a forced dissipative system. The range of behaviours exhibited defines a space that the responses of any simpler emulator model will need to span.
|
|
| 26. |
- Bieroza, Magdalena
(författare)
-
Fingerprinting hydrological and biogeochemical drivers of freshwater quality
- 2020
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 35
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding the interplay between hydrological flushing and biogeochemical cycling in streams is now possible owing to advances in high-frequency water quality measurements with in situ sensors. It is often assumed that storm events are periods when biogeochemical processes become suppressed and longitudinal transport of solutes and particulates dominates. However, high-frequency data show that diel cycles are a common feature of water quality time series and can be preserved during storm events, especially those of low-magnitude. In this study, we mine a high-frequency dataset and use two key hydrochemical indices, hysteresis and flushing index to evaluate the diversity of concentration-discharge relationships in third order agricultural stream. We show that mobilization patterns, inferred from the hysteresis index, change on a seasonal basis, with a predominance of rapid mobilization from surface and near stream sources during winter high-magnitude storm events and of delayed mobilization from subsurface sources during summer low-magnitude storm events. Using dynamic harmonic regression, we were able to separate concentration signals during storm events into hydrological flushing (using trend as a proxy) and biogeochemical cycling (using amplitude of a diel cycle as a proxy). We identified three groups of water quality parameters depending on their typical c-q response: flushing dominated parameters (phosphorus and sediments), mixed flushing and cycling parameters (nitrate nitrogen, specific conductivity and pH) and cycling dominated parameters (dissolved oxygen, redox potential and water temperature). Our results show that despite large storm to storm diversity in hydrochemical responses, storm event magnitude and timing have a critical role in controlling the type of mobilization, flushing and cycling behaviour of each water quality constituent. Hydrochemical indices can be used to fingerprint the effect of hydrological disturbance on freshwater quality and can be useful in determining the impacts of global change on stream ecology.
|
|
| 27. |
- Bishop, Kevin, et al.
(författare)
-
A primer for hydrology : the beguiling simplicity of Water's journey from rain to stream at 30 Preface
- 2015
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 29:16, s. 3443-3446
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Water's journey from rain to stream by Harald Grip and Allan Rodhe (1985, in Swedish: Vattnets vag fran regn till back) was one of the first textbooks to present groundwater contributions as a major feature of runoff generation, with implications for water quality and management. Three decades later, we have the privilege of presenting a special issue of Hydrological Processes, Runoff Generation in a Nordic Light: 30Years with Water's Journey from Rain to Stream' that seeks to introduce the book to a larger audience and continue the journey of ideas that the authors set in motion with their book.
|
|
| 28. |
- Bishop, Kevin, et al.
(författare)
-
A water cycle for the Anthropocene
- 2019
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 33, s. 3046-3052
-
Tidskriftsartikel (refereegranskat)
|
|
| 29. |
- Bishop, K., et al.
(författare)
-
Aqua Incognita: the unknown headwaters
- 2008
-
Ingår i: Hydological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 22, s. 1239–1242-
-
Tidskriftsartikel (refereegranskat)abstract
- Running water comprises just over one millionth of the world’s water. The importance of those streams and rivers as a resource for human welfare and biodiversity, however, is far out of proportion to that minuscule fraction. This explains why protecting running waters (the flow regimes, water quality and biota) is such a vital concern for society. Yet for all the focus and concern, how much do we actually know about these running waters, and the lotic habitat they comprise?
|
|
| 30. |
- Bishop, Kevin, et al.
(författare)
-
Water storage in a till catchment. II : Implications of transmissivity feedback for flow paths and turnover times
- 2011
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 25:25, s. 3950-3959
-
Tidskriftsartikel (refereegranskat)abstract
- This paper explores the flow paths and turnover times within a catchment characterized by the transmissivity feedback mechanism where there is a strong increase in the saturated hydraulic conductivity towards the soil surface and precipitation inputs saturate progressively more superficial layers of the soil profile. The analysis is facilitated by the correlation between catchment water storage and groundwater levels, which made it possible to model the daily spatial distribution of water storage, both vertically in different soil horizons and horizontally across a 6300-m2 till catchment. Soil properties and episodic precipitation input dynamics, combined with the influence of topographic features, concentrate flow in the horizontal, vertical, and temporal dimensions. Within the soil profile, there was a vertical concentration of lateral flow to superficial soil horizons (upper 30?cm of the soil), where much of the annual flow occurred during runoff episodes. Overland flow from a limited portion of the catchment can contribute to peak flows but is not a necessary condition for runoff episodes. The spatial concentration of flow, and the episodic nature of runoff events, resulted in a strong and spatially structured differentiation of local flow velocities within the catchment. There were large differences in the time spent by the laterally flowing water at different depths, with turnover times of lateral flow across a 1-m-wide soil pedon ranging from under 1?h at 10- to 20-cm depth to a month at 70- to 80-cm depth. In many regards, the hydrology of this catchment appears typical of the hydrology in till soils, which are widespread in Fenno-Scandia. Copyright (c) 2011 John Wiley & Sons, Ltd.
|
|
| 31. |
- Borris, Matthias, et al.
(författare)
-
Modelling the effects of changes in rainfall event characteristics on TSS loads in urban runoff
- 2014
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 28:4, s. 1787-1796
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of changes in rainfall event characteristics on urban stormwater quality, which was described by total suspended solids (TSS), was studied by means of computer simulations conducted with the Storm Water Management Model for a climate change scenario for northern Sweden. The simulation results showed that TSS event loads depended mainly on rainfall depth and intensity, but not on antecedent conditions. Storms with low-to-intermediate depths and intensities showed the highest sensitivity to changes in rainfall input, both for percentage and absolute changes in TSS wash-off loads, which was explained by the contribution of pervious areas and supply limitations. This has significant implications for stormwater management, because those relatively frequent events generally carry a high percentage of the annual pollutant load
|
|
| 32. |
- Brandimarte, Luigia, et al.
(författare)
-
Uncertainty in the estimation of backwater effects at bridge crossings
- 2013
-
Ingår i: Hydrological Processes. - : Wiley. - 1099-1085 .- 0885-6087. ; 27:9, s. 1292-1300
-
Tidskriftsartikel (refereegranskat)abstract
- The presence of a bridge spanning over a river and its floodplain alters the condition of flow. In subcritical conditions, which are typical in alluvial rivers, this flow alteration results in the so-called backwater effect, that is, an increase of the water surface elevation upstream of the structure as a response to increased energy losses. The extension of the expected backwater affected area and the increase in water surface elevation are highly dependent on the river morphology, bridge geometry, flow and floodplain characteristics and may originate upstream flooding. Thus, in many countries, at the stage of design a new bridge (or renovation works), a specific investigation on the backwater effect has to be undertaken to analyse its effect on the flooding of its vicinity. Bridge waterway hydraulics has been widely investigated in terms of practical research and some standard guidelines have been suggested for modelling the backwater effect at bridge crossings. Although the scientific literature has widely proven that hydraulic modelling is affected by many sources of uncertainty, the hydraulic modelling of backwater effects is still undertaken within a deterministic approach, based on the outcomes of a calibrated hydraulic model. This article aims at approaching the prediction of backwater effects at bridge crossings by accounting for the main sources of uncertainty affecting the hydraulic modelling exercise. A bridge over a highly vegetated floodplain (Tallahala Creek, Mississippi, USA) was considered for this analysis, and uncertainty in the model parameters and input data was assessed to predict backwater flood design profiles.
|
|
| 33. |
- Carey, Sean K., et al.
(författare)
-
Inter-comparison of hydro-climatic regimes across northern catchments : synchronicity, resistance and resilience
- 2010
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 24:24, s. 3591-3602
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 34. |
- Chen, Aifang, 1990, et al.
(författare)
-
Multidecadal variability of the Tonle Sap Lake flood pulse regime
- 2021
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 35:9
-
Tidskriftsartikel (refereegranskat)abstract
- Tonle Sap Lake (TSL) is one of the world's most productive lacustrine ecosystems, driven by the Mekong River's seasonal flood pulse. This flood pulse and its long-term dynamics under the Mekong River basin's (MRB) fast socio-economic development and climate change need to be identified and understood. However, existing studies fall short of sufficient time coverage or concentrate only on changes in water level (WL) that is only one of the critical flood pulse parameters influencing the flood pulse ecosystem productivity. Considering the rapidly changing hydroclimatic conditions in the Mekong basin, it is crucial to systematically analyse the changes in multiple key flood pulse parameters. Here, we aim to do that by using observed WL data for 1960-2019 accompanied with several parameters derived from a Digital Bathymetry Model. Results show significant declines of WL and inundation area from the late 1990s in the dry season and for the whole year, on top of increased subdecadal variability. Decreasing (increasing) probabilities of high (low) inundation area for 2000-2019 have been found, in comparison to the return period of inundation area for 1986-2000 (1960-1986). The mean seasonal cycle of daily WL in dry (wet) season for 2000-2019, compared to that for 1986-2000, has shifted by 10 (5) days. Significant correlations and coherence changes between the WL and large-scale circulations (i.e., El Nino-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and Indian Ocean Dipole (IOD)), indicate that the atmospheric circulations could have influenced the flood pulse in different time scales. Also, the changes in discharge at the Mekong mainstream suggest that anthropogenic drivers may have impacted the high water levels in the lake. Overall, our results indicate a declining flood pulse since the late 1990s.
|
|
| 35. |
- Chen, Haorui, et al.
(författare)
-
Forecasting the human and climate impacts on groundwater resources in the irrigated agricultural region of North China Plain
- 2023
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 37:3
-
Tidskriftsartikel (refereegranskat)abstract
- Climate change has caused significant impacts on water resource redistribution around the world and posed a great threat in the last several decades due to intensive human activities. The impacts of human water use and management on regional water resources remain unclear as they are intertwined with the impacts of climate change. In this study, we disentangled the impact of climate-induced human activities on groundwater resources in a typical region of the semi-arid North China Plain based on a process-oriented groundwater modelling approach accounting for climate-human-groundwater interactions. We found that the climate-induced human effect is amplified in water resources management ('amplifying effect') for our study region under future climate scenarios. We specifically derived a tipping point for annual precipitation of 350 mm, below which the climate-induced human activities on groundwater withdrawal will cause significant 'amplifying effect' on groundwater depletion. Furthermore, we explored the different pumping scenarios under various climate conditions and investigated the pumping thresholds, which the pumping amount should not exceed (4 x 10(7) m(3)) in order to control future groundwater level depletion. Our results highlight that it is critical to implement adaptive water use practices, such as water-saving irrigation technologies in the semi-arid regions, in order to mitigate the negative impacts of groundwater overexploitation, particularly when annual precipitation is anomalously low.
|
|
| 36. |
- Chen, X., et al.
(författare)
-
A distributed monthly hydrological model for integrating spatial variations of basin topography and rainfall
- 2007
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 21:2, s. 242-252
-
Tidskriftsartikel (refereegranskat)abstract
- Hydrological models at a monthly time-scale are important tools for hydrological analysis, such as in impact assessment of climate change and regional water resources planning. Traditionally, monthly models adopt a conceptual, lumped-parameter approach and cannot account for spatial variations of basin characteristics and climatic inputs. A large requirement for data often severely limits the utility of physically based, distributed-parameter models. Based on the variable-source-area concept, we considered basin topography and rainfall to be two major factors whose spatial variations play a dominant role in runoff generation and developed a monthly model that is able to account for their influences in the spatial and temporal dynamics of water balance. As a hybrid of the Xinanjiang model and TOPMODEL, the new model is constructed by innovatively making use of the highly acclaimed simulation techniques in the two existing models. A major contribution of this model development study is to adopt the technique of implicit representation of soil moisture characteristics in the Xinanjiang model and use the TOPMODEL concept to integrate terrain variations into runoff simulation. Specifically, the TOPMODEL topographic index ln(a/tan) is converted into an index of relative difficulty in runoff generation (IRDG) and then the cumulative frequency distribution of IRDG is used to substitute the parabolic curve, which represents the spatial variation of soil storage capacity in the Xinanjiang model. Digital elevation model data play a key role in the modelling procedures on a geographical information system platform, including basin segmentation, estimation of rainfall for each sub-basin and computation of terrain characteristics. Other monthly data for model calibration and validation are rainfall, pan evaporation and runoff. The new model has only three parameters to be estimated, i.e. watershed-average field capacity WM, pan coefficient and runoff generation coefficient . Sensitivity analysis demonstrates that runoff is least sensitive to WM and, therefore, it can be determined by a prior estimation based on the climate and soil properties of the study basin. The other two parameters can be determined using optimization methods. Model testing was carried out in a number of nested sub-basins of two watersheds (Yuanjiang River and Dongjiang River) in the humid region in central and southern China. Simulation results show that the model is capable of describing spatial and temporal variations of water balance components, including soil moisture content, evapotranspiration and runoff, over the watershed. With a minimal requirement for input data and parameterization, this terrain-based distributed model is a valuable contribution to the ever-advancing technology of hydrological modelling.
|
|
| 37. |
- Chen, Xi, et al.
(författare)
-
Simulating the integrated effects of topography and soil properties on runoff generation in hilly forested catchments, South China
- 2010
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 24:6, s. 714-725
-
Tidskriftsartikel (refereegranskat)abstract
- Estimation of runoff components associated with catchment topography and soil properties is critical for planning water resources utilization and evaluating hydrological changes due to artificially induced land surface manipulation. In this study, the modified TOPMODEL by Scanlon et al. (2000) was applied to simulate runoff-generating processes and to separate runoff components in two hilly forested catchments within the Dongjiang Basin of Southeast China. The modified TOPMODEL was improved by integrating an evapotranspiration package with the model algorithms. Influences of catchment topography and soil properties on runoff generation were analysed on the basis of explicit expression of catchment field capacity distribution derived from the topographic index and catchment average field capacity. Study results demonstrate that the model is capable of simulating hydrological processes and separate hydrological components in both hourly and daily time steps. Total runoff generation primarily depends on the effective storage capacity of unsaturated zone. A 50% decrease of the effective storage capacity from 0.22 to 0.11 m over the soil zone leads to a 6.6% increase in total runoff. Topography plays a dominant role in formation of runoff components. When the catchment mean slope increases by 87%, subsurface storm flow could increase by 50% whilst overland flow decreases by 7.5% and baseflow by 6.7%. Vertical changes of soil permeability influence runoff components as well. Decrease of the lower layer hydraulic transmissivity may result in 2-3% increase of overland flow and subsurface storm flow and 5% decrease of baseflow.
|
|
| 38. |
- Chen, Yuanying, et al.
(författare)
-
Nutrient source attribution : Quantitative typology distinction of active and legacy source contributions to waterborne loads
- 2021
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 35:7
-
Tidskriftsartikel (refereegranskat)abstract
- Distinction between active and legacy sources of nutrients is needed for effective reduction of waterborne nutrient loads and associated eutrophication. This study quantifies main typological differences in nutrient load behaviour versus water discharge for active and legacy sources. This quantitative typology is used for source attribution based on monitoring data for water discharge and concentrations of total nitrogen (TN) and total phosphorous (TP) from 37 catchments draining into the Baltic Sea along the coastline of Sweden over the period 2003-2013. Results indicate dominant legacy source contributions to the monitored loads of TN and TP in most (33 of the total 37) study catchments. Dominant active sources are indicated in 1 catchment for TN, and mixed sources are indicated in 3 catchments for TN, and 4 catchments for TP. The TN and TP concentration contributions are quantified to be overall higher from the legacy than the active sources. Legacy concentrations also correlate well with key indicators of human activity in the catchments, agricultural land share for TN (R-2 = 0.65) and population density for TP (R-2 = 0.56). Legacy-dominated nutrient concentrations also change more slowly than in catchments with dominant active or mixed sources. Various data-based results and indications converge in indicating legacy source contributions as largely dominant, mainly anthropogenic, and with near-zero average change trends in the present study of catchments draining into the Baltic Sea along the coastline of Sweden, as in other parts of the world. These convergent indications emphasize needs to identify and map the different types of sources in each catchment, and differentiate strategies and measures to target each source type for possible achievement of shorter- and longer-term goals of water quality improvement.
|
|
| 39. |
- Coluccio, K., et al.
(författare)
-
Mapping groundwater discharge to a coastal lagoon using combined spatial airborne thermal imaging, radon (Rn-222) and multiple physicochemical variables
- 2020
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085.
-
Tidskriftsartikel (refereegranskat)abstract
- Coastal lagoons are significant wetland environments found on coastlines throughout the world. Groundwater seepage may be a key component of lagoon water balances, though only a few studies have investigated large (>100 km(2)) coastal lagoons. In this study, we combined airborne thermal infrared imagery with continuous measurements of radon (Rn-222-a natural groundwater tracer), conductivity, water temperature and dissolved oxygen to map groundwater seepage to a large coastal lagoon in New Zealand. We found evidence of seepage along the margins of the lagoon but not away from the margins. Our findings confirmed previously known seepage zones and identified new potential locations of groundwater inflow. Both point source and diffuse seepage occurred on the western and northwestern margins of the lagoon and parallel to the barrier between the lagoon and sea. These observations imply geologic controls on seepage. The combination of remote sensing and in-situ radon measurements allowed us to effectively map groundwater discharge areas across the entire lagoon. Combined, broad-scale qualitative methods built confidence in our interpretation of groundwater discharge locations in a large, dynamic coastal lagoon.
|
|
| 40. |
- Dahlke, Helen E., et al.
(författare)
-
Isotopic investigation of runoff generation in a glacierized catchment in northern Sweden
- 2014
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 28:3, s. 1383-1398
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, summer rainfall contributions to streamflow were quantified in the sub-arctic, 30% glacierized Tarfala (21.7km(2)) catchment in northern Sweden for two non-consecutive summer sampling seasons (2004 and 2011). We used two-component hydrograph separation along with isotope ratios (O-18 and D) of rainwater and daily streamwater samplings to estimate relative fraction and uncertainties (because of laboratory instrumentation, temporal variability and spatial gradients) of source water contributions. We hypothesized that the glacier influence on how rainfall becomes runoff is temporally variable and largely dependent on a combination of the timing of decreasing snow cover on glaciers and the relative moisture storage condition within the catchment. The results indicate that the majority of storm runoff was dominated by pre-event water. However, the average event water contribution during storm events differed slightly between both years with 11% reached in 2004 and 22% in 2011. Event water contributions to runoff generally increased over 2011 the sampling season in both the main stream of Tarfala catchment and in the two pro-glacial streams that drain Storglaciaren (the largest glacier in Tarfala catchment covering 2.9km(2)). We credit both the inter-annual and intra-annual differences in event water contributions to large rainfall events late in the summer melt season, low glacier snow cover and elevated soil moisture due to large antecedent precipitation. Together amplification of these two mechanisms under a warming climate might influence the timing and magnitude of floods, the sediment budget and nutrient cycling in glacierized catchments.
|
|
| 41. |
- Dahlke, Helen E., et al.
(författare)
-
Using concurrent DNA tracer injections to infer glacial flow pathways
- 2015
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 29:25, s. 5257-5274
-
Tidskriftsartikel (refereegranskat)abstract
- Catchment hydrology has become replete with flow pathway characterizations obtained via combinations of physical hydrologic measurements (e.g. streamflow hydrographs) and natural tracer signals (e.g. stable water isotopes and geochemistry). In this study, we explored how our understanding of hydrologic flow pathways can be improved and expanded in both space and time by the simultaneous application of engineered synthetic DNA tracers. In this study, we compared the advective-dispersive transport properties and mass recovery rates of two types of synthetic DNA tracers, one consisting of synthetic DNA strands encapsulated into biodegradable microspheres and another consisting of `free' DNA, i.e. not encapsulated. The DNA tracers were also compared with a conservative fluorescent dye. All tracers were injected into a small (3.2-km(2)) valley glacier, Storglaciaren, in northern Sweden. Seven of the nine DNA tracers showed clear recovery during the sampling period and similar peak arrival times and dispersion coefficients as the conservative fluorescent dye. However, recovered DNA tracer mass ranged only from 1% to 66%, while recovered fluorescent dye mass was 99%. Resulting from the cold and opaque subglacial environment provided by the glacier, mass loss associated with microbial activity and photochemical degradation of the DNA is likely negligible, leaving sorption of DNA tracers onto suspended particles and loss of microtracer particles to sediment storage as probable explanations. Despite the difference in mass recovery, the advection and dispersion information derived from the DNA tracer breakthrough curves provided spatially explicit information that allowed inferring a theoretical model of the flow pathways that water takes through the glacier.
|
|
| 42. |
- Darracq, Amelie, et al.
(författare)
-
Scale and model resolution effects on the distributions of advective solute travel times in catchments
- 2010
-
Ingår i: Hydrological Processes. - : John Wiley & Sons, Ltd.. - 0885-6087 .- 1099-1085. ; 24:12, s. 1697-1710
-
Tidskriftsartikel (refereegranskat)abstract
- Advective solute travel times and their distributions in hydrological catchments are useful descriptors of the dynamics and variation of the physical mass transport among and along the different source-to-recipient pathways of solute transport through the catchments. This article investigates the scale dependence and the effects of model and data resolution on the quantification of advective travel times and their distributions in the Swedish catchment areas of Norrström and Forsmark. In the surface water networks of the investigated (sub)catchments, the mean advective travel time increases with (sub)catchment scale, whereas the relative travel time variability around the mean value (coefficient of variation, CV) is scale-invariant and insensitive to model resolution. In the groundwater and for the whole (sub)catchments, both the mean value and the CV of travel times are scale-invariant, but sensitive to model resolution and accuracy. Such quantifications and results of advective travel times constitute important steps in the development of improved understanding and modelling of nutrient, pollutant and tracer transport through catchments.
|
|
| 43. |
- Davies, Jessica A. C., et al.
(författare)
-
Hysteresis and scale in catchment storage, flow and transport
- 2015
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 29:16, s. 3604-3615
-
Tidskriftsartikel (refereegranskat)abstract
- The closure problem of representing hydrological boundary fluxes given the state of the system has been described as the scientific Holy Grail' of hydrology. This relationship between storage state and flux should be hysteretic and scale dependent because of the differences between velocities and celerities in a hydrological systemeffectively velocities are storage controlled, and celerities are controlled by storage deficits. To improve our understanding of the nature of these relationships a new hydrology model is used (the Multiple Interacting Pathways or MIPs model) to explore the influence of catchment scale on storage-flow-transport relationships, and their non-linearities. The MIPs model has been shown to produce acceptable simulations of both flow and tracer, i.e. of both celerities and velocities, at the Gardsjon catchment in Sweden. In this study the model is used to simulate scaled versions of the Gardsjon catchment to allow us for the first time to investigate the influence of scale on the non-linearities in storage-flow-transport relationships, and help us steer the quest for the scientific hydrological Holy Grail'. The simulations reveal the influence of scale on flow response in the nature of storage-discharge hysteresis and its links with antecedent storage; fractal-like systematic change of mean output travel times with scale; the effect of scale on input, output and storage residence time distributions; hysteric relations between storage and output travel times and links between storage and water table level hysteresis. (c) 2015 The Authors. Hydrological Processes published by John Wiley & Sons Ltd.
|
|
| 44. |
- Davies, Jessica, et al.
(författare)
-
A discrete particle representation of hillslope hydrology : hypothesis testing in reproducing a tracer experiment at Gardsjon, Sweden
- 2011
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 25:23, s. 3602-3612
-
Tidskriftsartikel (refereegranskat)abstract
- Despite the long history of the continuum equation approach in hydrology, it is not a necessary approach to the formulation of a physically based representation of hillslope hydrology. The Multiple Interacting Pathways ( MIPs) model is a discrete realization that allows hillslope response and transport to be simultaneously explored in a way that reflects the potential occurrence of preferential flows and lengths of pathways. The MIPs model uses random particle tracking methods to represent the flow of water within the subsurface alongside velocity distributions that acknowledge preferential flows and transition probability matrices, which control flow pathways. An initial realization of this model is presented here in application to a tracer experiment carried out in Gardsjon, Sweden. The model is used as an exploratory tool, testing several hypotheses in relation to this experiment.
|
|
| 45. |
|
|
| 46. |
|
|
| 47. |
- Destouni, Georgia, et al.
(författare)
-
Distinguishing active and legacy source contributions to stream water quality : Comparative quantification for chloride and metals
- 2021
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 35:7
-
Tidskriftsartikel (refereegranskat)abstract
- Hydrochemical constituents in streams may originate from currently active sources at the surface and/or legacy sources from earlier surface inputs, waste deposits and land contamination. Distinction and quantification of these source contributions are needed for improved interpretation of tracer data and effective reduction of waterborne environmental pollutants. This article develops a methodology that recognizes and quantifies some general mechanistic differences in stream concentration and load behavior versus discharge between such source contributions. The methodology is applied to comparative analysis of stream concentration data for chloride (Cl-), copper (Cu), lead (Pb), and zinc (Zn), and corresponding data for water discharge, measured over the period 1990-2018 in multiple hydrological catchments (19 for Cl-, 11 for Cu and Zn, 10 for Pb) around the major Lake Malaren in Sweden. For Cl-, the average load fraction of active sources is quantified to be 19%, and the average active and legacy concentration contributions as 2.9 and 11 mg/L, respectively. For the metals, the average active load fractions at outlets are 1%-3% over all catchments and 9%-14% in the relatively few catchments with mixed metal sources. Average active and legacy concentration contributions are 0.14 and 3.2 mu g/L for Cu, 0.05 and 1.5 mu g/L for Pb, and 1.4 and 12 mu g/L for Zn, respectively. This multi-catchment analysis thus indicates a widespread prevalence of legacy sources, with greater legacy than active concentration contributions for both Cl- and the metals, and active contributions playing a greater role for chloride than for the metals. The relatively simple first-order methodology developed and applied in the study can be used to screen commonly available stream monitoring data for possible distinction of active and legacy contributions of any hydrochemical constituent in and across various hydrological catchment settings.
|
|
| 48. |
- Di Baldassarre, Giuliano, et al.
(författare)
-
Is the current flood of data enough? : A treatise on research needs for the improvement of flood modelling
- 2012
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087. ; 26:1, s. 153-158
-
Tidskriftsartikel (refereegranskat)abstract
- Flood disasters account for more than 40% of all natural hazardsworldwide and about half of all deaths caused by natural catastrophes(Ohl and Tapsell, 2000). For instance, in 2010, according to theEmergency Events Database (EM-DAT, 2011) floods were responsible forthe loss of more than 8000 human lives and affected about 180 millionpeople. The catastrophic floods in Pakistan and Australia are the mostrecent examples of a worldwide increasing human exposure to flood risk.Figure 1 reports the number of fatalities caused by floods in Africa inthe period 1950–2009 (EM-DAT, 2011).The diagram shows that the number of flood fatalities in Africa hasdramatically increased by more than an order of magnitude in the last60 years (Figure 1). These dramatic figures indicate a need for urgentactions to decrease these staggering numbers (Di Baldassarreet al.,2010a).The flood risk is likely to grow further because of many factors,such as changing demographics, land use changes, climate variabilityand change, technological and socio-economic conditions, industrialdevelopment, urban expansion and infrastructure construction in flood-prone areas as well as unplanned human settlement in floodplains(UN-ISDR Scientific and Technical Committee, 2009). To mitigate thecontinuously increasing flood risk the currently proposed approach isintegrated flood management (more towards ‘living with floods’) that hasreplaced the more traditional flood defense approach (‘fighting floods’).This approach aims to minimize the human, economic and ecologicallosses from extreme floods while at the same time maximising the social,economic and ecological benefits of ordinary floods (e.g. UNESCO-IFI:International Flood Initiative).In this context, the aim of this commentary is twofold. First, to criti-cally discuss the current opportunities for improving flood modelling,which are offered by the increased availability of new data sources,such as the utilisation of remote sensing data of higher resolution andthe increasing availability of globally and freely accessible space-bornedata. Second, to discuss knowledge gaps and research needs to fullyand properly exploit this current ‘flood of data’ (Lincoln, 2007) andimprove flood modelling. This leads to the proposed elements of a futureresearch agenda to support the scientific basis of integrated flood management.
|
|
| 49. |
- Di Baldassarre, Giuliano, et al.
(författare)
-
Near real time satellite imagery to support and verify timely flood modelling
- 2009
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 23:5, s. 799-803
-
Tidskriftsartikel (refereegranskat)abstract
- The study investigates the capability of coarse resolution synthetic aperture radar (SAR) imagery to support flood inundation models. A hydraulic model of a 98-km reach of the River Po (Northern Italy) was calibrated on the October 2000 high-magnitude flood event with extensive and high-quality field data. During the June 2008, low-magnitude flood event a SAR image was acquired and processed in near real time (NRT) in order to provide adequate data for quick verification and recalibration of the hydraulic model.
|
|
| 50. |
- Divine, D. V., et al.
(författare)
-
Modelling the regional climate and isotopic composition of Svalbard precipitation using REMOiso : a comparison with available GNIP and ice core data
- 2011
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 25:24, s. 3748-3759
-
Tidskriftsartikel (refereegranskat)abstract
- Simulations of a regional (approx. 50 km resolution) circulation model REMOiso with embedded stable water isotope module covering the period 1958-2001 are compared with the two instrumental climate and four isotope series (d18O) from western Svalbard. We examine the data from ice cores drilled on Svalbard ice caps in 1997 (Lomonosovfonna, 1250 m asl) and 2005 (Holtedahlfonna, 1150 m asl) and the GNIP series from Ny-angstrom lesund and Isfjord Radio. The surface air temperature (SAT) and precipitation data from Longyearbyen and Ny-angstrom lesund are used to assess the skill of the model in reproducing the local climate. The model successfully captures the climate variations on the daily to multidecadal times scales although it tends to systematically underestimate the winter SAT. Analysis suggests that REMOiso performs better at simulating isotope compositions of precipitation in the winter than summer. The simulated and measured Holtedahlfonna d18O series agree reasonably well, whereas no significant correlation has been observed between the modelled and measured Lomonosovfonna ice core isotopic series. It is shown that sporadic nature as well as variability in the amount inherent in precipitation process potentially limits the accuracy of the past SAT reconstruction from the ice core data. This effect in the study area is, however, diminished by the role of other factors controlling d18O in precipitation, most likely sea ice extent, which is directly related with the SAT anomalies.
|
|
