| 1. |
- McNamara, James P., et al.
(författare)
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Storage as a Metric of Catchment Comparison
- 2011
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 25:21, s. 3364-3371
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Tidskriftsartikel (refereegranskat)abstract
- The volume of water stored within a catchment, and its partitioning among groundwater, soil moisture, snowpack, vegetation, and surface water are the variables that ultimately characterize the state of the hydrologic system. Accordingly, storage may provide useful metrics for catchment comparison. Unfortunately, measuring and predicting the amount of water present in a catchment is seldom done; tracking the dynamics of these stores is even rarer. Storage moderates fluxes and exerts critical controls on a wide range of hydrologic and biologic functions of a catchment. While understanding runoff generation and other processes by which catchments release water will always be central to hydrologic science, it is equally essential to understand how catchments retain water. We have initiated a catchment comparison exercise to begin assessing the value of viewing catchments from the storage perspective. The exercise is based on existing data from five watersheds, no common experimental design, and no integrated modelling efforts. Rather, storage was estimated independently for each site. This briefing presents some initial results of the exercise, poses questions about the definitions and importance of storage and the storage perspective, and suggests future directions for ongoing activities. Copyright. (C) 2011 John Wiley & Sons, Ltd.
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| 2. |
- Seibert, J., 1968-, et al.
(författare)
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Water storage in a till catchment. I : Distributed modelling and relationship to runoff
- 2011
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 25:25, s. 3937-3949
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Tidskriftsartikel (refereegranskat)abstract
- Although water storage is an important variable to understand the hydrological functioning of a catchment, it is challenging to estimate the total water storage in a catchment. Catchment water storage can be estimated on the basis of water balance, but this approach is prone to errors in the different water balance terms. Here, an approach is presented to estimate the daily dynamics of catchment-wide soil water and groundwater storage on the basis of groundwater-level observations, soil properties and an assumption of hydrological equilibrium above the water table. This approach was applied to a 6300-m2 till catchment in Southwest Sweden. The predicted mean catchment water storage between April 1991 and June 1992 was 210mm and ranged from 190 to 260mm. The estimated water storage followed runoff rates closely especially during recession periods. On average, 79% of the water storage was held in the unsaturated zone, and the remaining 21% was groundwater, but this proportion varied strongly with runoff and total storage. During dry conditions, unsaturated storage accounted for at maximum 95% of the water storage; during wet conditions, this number dropped to 40%. Copyright (c) 2011 John Wiley & Sons, Ltd.
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| 3. |
- Fischer, Benjamin M. C., et al.
(författare)
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Investigating the impacts of biochar on water fluxes in a rice experiment in the dry corridor of Central America, Costa Rica
- 2022
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 36:12
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Tidskriftsartikel (refereegranskat)abstract
- Amending soils with biochar, a pyrolyzed organic material, is an emerging practice to potentially increase plant available water and reduce the risks associated with climatic variability in traditionally-rainfed tropical agricultural systems. To investigate the impacts of biochar amendment on soil water storage relative to non-amended soils, we performed an upland rice field experiment in a tropical seasonally dry region of Costa Rica consisting of plots with two different biochar amendments and a control plot. Across all plots, we collected hydrometric and isotopic data (δ18O and δ2H of rain, mobile soil, ground and rice xylem water). We observed that the soil water retention curves for biochar treated soils shifted, indicating that rice plants had 2% to 7% more water available throughout the growing season relative to the control plots and thus could withstand dry spells up to seven extra days. Furthermore, the isotopic composition of plant water in biochar and control treatments were rather similar, indicating that rice plants in different treatments likely consumed similar water. Hence, we observed that biochar amendments can stabilize water supplies for the rice plants; however, still supplemental irrigation was required to facilitate plant growth during extended dry periods. Ultimately, our findings indicate, that biochar amendments can complement, but not necessarily replace, other water management strategies to help reduce the threat of rainfall variability to rainfed agriculture in tropical regions.
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| 4. |
- Ali, Genevieve, et al.
(författare)
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Comparison of threshold hydrologic response across northern catchments
- 2015
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 29:16, s. 3575-3591
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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.
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| 5. |
- Chen, Yuanying, et al.
(författare)
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Nutrient source attribution : Quantitative typology distinction of active and legacy source contributions to waterborne loads
- 2021
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 35:7
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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.
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| 6. |
- Grip, Harald
(författare)
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Sweden's first forest hydrology field study 1905-1926: contemporary relevance of inherited conclusions and data from the Rokliden Hillslope
- 2015
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 29, s. 3616-3631
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Tidskriftsartikel (refereegranskat)abstract
- During the last decades of the 19th century, a great worry arose about forest landscape paludification in Northern Sweden. This was the original impetus for forest hydrological research in Sweden, and the Swedish Institute of Experimental Forestry established the first field research site in 1905 at Rokliden, close to Pitea in North Sweden. It comprised 8.64ha located 2km down a 3-km-long gently sloping (similar to 4%), north facing Norway spruce covered till slope, interspersed with small mires. By 1931, it was concluded that paludification was not spreading across Northern Sweden at an appreciable rate. Within the Rokliden research site, 22 groundwater wells were installed and levels measured weekly until 1926. A map with 0.5m equidistance, ten vegetation classes, and soil profiles was established. Groundwater flow velocity was estimated by tracing added sodium chloride. Hydraulic conductivity was measured on undisturbed soil cores, while mechanical and chemical analyses were carried out on other samples. Groundwater was collected and analysed for dissolved compounds including oxygen. Hydrology was found important for soil types and vegetation development. The necessary profile drainage for podzol soil development was identified as vein drainage at the bedrock surface. Modern measurements in the re-established groundwater observation network and re-analysis of old data confirmed the plausibility of these original conclusions. Partial catchment area could explain rates of both groundwater level rise and recession. Revisiting this field study reveals that many issues in contemporary hillslope hydrology were already established a century ago, even though the provenance of that knowledge is not generally recognized. Copyright (c) 2014 John Wiley & Sons, Ltd.
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| 7. |
- Joel, Abraham, et al.
(författare)
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Modelling discharge from a coastal watershed in southeast Sweden using an integrated framework
- 2010
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 24, s. 3837-3851
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Tidskriftsartikel (refereegranskat)abstract
- The field hydrology model DRAINMOD integrated with Arc Hydro in geographical information system (GIS) framework (Arc Hydro-DRAINMOD) was used to simulate the hydrological response of a coastal watershed in southeast Sweden. Arc Hydro-DRAINMOD uses a distributed approach to route water from each field edge to the watershed outlet. In the framework the Arc Hydro data model was used to describe the stream network in the watershed and to connect the individual simulated DRAINMOD-field outflow time series from each plot using Arc Hydro schema-links features, which were summed at Arc Hydro schema-nodes features along the stream network to generate the stream network flow. Hydrology data collected during six periods between 2003 and 2008 were used to test Arc Hydro-DRAINMOD and its performance was evaluated by considering uncertainties in model inputs using generalized likelihood uncertainty estimation (GLUE). The GLUE estimates obtained (uncertainty bands 5% and 95%) agreed satisfactorily with measured monthly discharges. The percentage of time in which the observed discharges were bracketed by the uncertainty bands was 88% in calibration periods and 75% in validation periods. Although monthly time step simulations showed good agreement with observed discharges during the two main discharge events in spring, the contradictory daily time step results indicate that the watershed response simulations on a daily basis need to be improved. The uncertainty analysis showed that in periods of higher discharge, such as spring periods, the uncertainty in prediction was higher. It is important to note that these uncertainty estimations using the GLUE procedure include the uncertainties in measured discharge values, model inputs, boundary conditions and model structures. It was estimated that stream baseflow represented 42% of the total watershed discharge, but further research is needed to confirm this. These results show that the new Arc Hydro-DRAINMOD framework is applicable for predicting discharge from artificially drained watersheds in southeast Sweden. Copyright (C) 2010 John Wiley & Sons, Ltd.
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| 8. |
- Juston, John, et al.
(författare)
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Temporal sampling strategies and uncertainty in calibrating a conceptual hydrological model for a small boreal catchment
- 2009
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 23:21, s. 3093-3109
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Tidskriftsartikel (refereegranskat)abstract
- How much data is needed for calibration of a hydrological catchment model? In this paper we address this question by evaluating the information contained in different subsets of discharge and groundwater time series for multi-objective calibration of a conceptual hydrological model within the framework of an uncertainty analysis. The study site was a 5.6-km(2) catchment within the Forsmark research site in central Sweden along the Baltic coast. Daily time series data were available for discharge and several groundwater wells within the catchment for a continuous 1065-day period. The hydrological model was a site-specific modification of the Conceptual HBV model. The uncertainty analyses were based on a selective Monte Carlo procedure. Thirteen subsets of the complete time series data were investigated with the idea that these represent realistic intermittent sampling strategies. Data Subsets included split-samples and various combinations of weekly, monthly, and quarterly fixed interval subsets, as well as a 53-day 'informed observer' Subset that utilized once per month samples except during March and April-the months containing large and often dominant snow melt events-when sampling was once per week. Several of these subsets, including that of the informed observer, provided very similar constraints on model calibration and parameter identification as the full data record, ill terms of credibility bands on simulated time series, posterior parameter distributions, and performance indices calculated to the full dataset. This result Suggests that hydrological sampling designs can, at least in some cases, be optimized. Copyright (C) 2009 John Wiley & Sons, Ltd.
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| 9. |
- Karlsen, Reinert, et al.
(författare)
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The assumption of uniform specific discharge : unsafe at Any time?
- 2016
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 0:21, s. 3978-3988
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Tidskriftsartikel (refereegranskat)abstract
- 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 68km(2) 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.
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| 10. |
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