Vulnerability of groundwater resources to interaction with river water in a boreal catchment
Summary: Based on low-altitude aerial infrared surveys, around 370 groundwater–surface water interaction sites were located. Longitudinal temperature patterns, stable isotopes and dissolved silica composition of the studied rivers differed. Interaction sites identified in the proximity of 12 municipal water plants during low-flow seasons should be considered as potential risk areas during flood periods and should be taken under consideration in river basin management under changing climatic situations.
Hydrol. Earth Syst. Sci., 19, 3015-3032, doi:10.5194/hess-19-3015-2015, 2015
Data assimilation in integrated hydrological modeling using ensemble Kalman filtering: evaluating the effect of ensemble size and localization on filter performance
Hydrol. Earth Syst. Sci., 19, 2999-3013, doi:10.5194/hess-19-2999-2015, 2015
Propagation of hydro-meteorological uncertainty in a model cascade framework to inundation prediction
Summary: The study is an investigation on the propagation of hydro-meteorological uncertainty within a model cascade applied to flood prediction. Uncertainty is evaluated at meteorological and hydrological levels in a hindcast scenario, which allows for its generation from the rainfall prediction to its interaction at a catchment level, and propagation to an estimated inundation area and depth. A complex aggregation of errors is demonstrated with larger effect on inundation depths than flood extents.
Hydrol. Earth Syst. Sci., 19, 2981-2998, doi:10.5194/hess-19-2981-2015, 2015
Analyses of uncertainties and scaling of groundwater level fluctuations
Summary: The error or uncertainty in head, obtained with an analytical or numerical solution, at an early time is mainly caused by the random initial condition. The error reduces with time, later reaching a constant error. The constant error at a later time is mainly due to the effects of the uncertain source/sink. The error caused by the uncertain boundary is limited to a narrow zone. Temporal scaling of head exists in most parts of a low permeable aquifer, mainly caused by recharge fluctuation.
Hydrol. Earth Syst. Sci., 19, 2971-2979, doi:10.5194/hess-19-2971-2015, 2015
Technical Note: Semi-automated effective width extraction from time-lapse RGB imagery of a remote, braided Greenlandic river
Summary: Here, we give a semi-automated processing workflow to extract hydraulic parameters from over 10,000 time-lapse images of the remote Isortoq River in Greenland. This workflow allows efficient and accurate (mean accuracy 79.6%) classification of images following an automated similarity filtering process. We also give an effective width hydrograph (a proxy for discharge) for the Isortoq using this workflow, showing the potential of this workflow for enhancing understanding of remote rivers.
Hydrol. Earth Syst. Sci., 19, 2963-2969, doi:10.5194/hess-19-2963-2015, 2015
Projected changes in US rainfall erosivity
Summary: We estimate future changes in US erosivity from the most recent ensemble projections of daily and monthly rainfall accumulation. The expectation of overall increase in erosivity is confirmed by these calculations, but a quantitative assessment is marred by large uncertainties. Specifically, the uncertainty in the method of estimation of erosivity is more consequential than that deriving from the spread in climate simulations, and leads to changes of uncertain sign in parts of the south.
Hydrol. Earth Syst. Sci., 19, 2945-2961, doi:10.5194/hess-19-2945-2015, 2015
Corrigendum to "Laser vision: lidar as a transformative tool to advance critical zone science" published in Hydrol. Earth Syst. Sci., 19, 2881–2897, 2015
Hydrol. Earth Syst. Sci., 19, 2943-2943, doi:10.5194/hess-19-2943-2015, 2015
TopREML: a topological restricted maximum likelihood approach to regionalize trended runoff signatures in stream networks
Summary: We introduce TopREML as a method to predict runoff signatures in ungauged basins using linear mixed models with spatially correlated random effects. The nested nature of streamflow networks is accounted for by allowing for stronger correlations between flow-connected basins. The restricted maximum likelihood framework provides best linear unbiased predictions of both the predicted flow variable and its uncertainty as shown in Monte Carlo and cross-validation analyses in Nepal and Austria.
Hydrol. Earth Syst. Sci., 19, 2925-2942, doi:10.5194/hess-19-2925-2015, 2015
Operational aspects of asynchronous filtering for flood forecasting
Summary: This is the first analysis of the asynchronous ensemble Kalman filter in hydrological forecasting. The results of discharge assimilation into a hydrological model for the catchment show that including past predictions and observations in the filter improves model forecasts. Additionally, we show that elimination of the strongly non-linear relation between soil moisture and assimilated discharge observations from the model update becomes beneficial for improved operational forecasting.
Hydrol. Earth Syst. Sci., 19, 2911-2924, doi:10.5194/hess-19-2911-2015, 2015
The water balance components of undisturbed tropical woodlands in the Brazilian cerrado
Summary: We determined the main components of the water balance for an undisturbed cerrado. Evapotranspiration ranged from 1.91 to 2.60mm per day for the dry and wet seasons, respectively. Canopy interception ranged from 4 to 20% and stemflow values were approximately 1% of gross precipitation. The average runoff coefficient was less than 1%, while cerrado deforestation has the potential to increase that amount up to 20-fold. The water storage may be estimated by the difference between P and ET.
Hydrol. Earth Syst. Sci., 19, 2899-2910, doi:10.5194/hess-19-2899-2015, 2015
Laser vision: lidar as a transformative tool to advance critical zone science
Summary: This review's objective is to demonstrate the transformative potential of lidar by critically assessing both challenges and opportunities for transdisciplinary lidar applications in geomorphology, hydrology, and ecology. We find that using lidar to its full potential will require numerous advances, including more powerful open-source processing tools, new lidar acquisition technologies, and improved integration with physically based models and complementary observations.
Hydrol. Earth Syst. Sci., 19, 2881-2897, doi:10.5194/hess-19-2881-2015, 2015
Towards observation-based gridded runoff estimates for Europe
Summary: Water storages and fluxes on land are key variables in the Earth system. To provide context for local investigations and to understand phenomena that emerge at large spatial scales, information on continental freshwater dynamics is needed. This paper presents a methodology to estimate continental-scale runoff on a 0.5° spatial grid, which combines the advantages of in situ observations with the power of machine learning regression. The resulting runoff estimates compare well with observations.
Hydrol. Earth Syst. Sci., 19, 2859-2879, doi:10.5194/hess-19-2859-2015, 2015
A 2-D process-based model for suspended sediment dynamics: a first step towards ecological modeling
Summary: Suspended sediment concentration (SSC) levels are important indicator for the ecology of estuaries. Observations of SSC are difficult to make, therefore we revert to coupled 2-D hydrodynamic-sediment process-based transport models to make predictions in time (seasonal and yearly) and space (meters to kilometers). This paper presents calibration/validation of SSC for the Sacramento-San Joaquin Delta and translates SSC to turbidity in order to couple with ecology models.
Hydrol. Earth Syst. Sci., 19, 2837-2857, doi:10.5194/hess-19-2837-2015, 2015
Including the dynamic relationship between climatic variables and leaf area index in a hydrological model to improve streamflow prediction under a changing climate
Hydrol. Earth Syst. Sci., 19, 2821-2836, doi:10.5194/hess-19-2821-2015, 2015
Turbidity in the fluvial Gironde Estuary (southwest France) based on 10-year continuous monitoring: sensitivity to hydrological conditions
Summary: This study aims to analyse for the first time suspended sediment dynamics in the fluvial Gironde through a unique set of a 10-year continuous turbidity record. We demonstrate the following: the interest of turbidity-discharge hysteresis loops to evaluate the presence of sediment depositions; the relationships between features of the turbidity maximum zone (TMZ) and river flow; and the definition of hydrological indicators of the persistence and concentration of the TMZ.
Hydrol. Earth Syst. Sci., 19, 2805-2819, doi:10.5194/hess-19-2805-2015, 2015
Revised predictive equations for salt intrusion modelling in estuaries
Summary: We revised the predictive equations for two calibrated parameters in salt intrusion model (the Van der Burgh coefficient K and dispersion coefficient D) using an extended database of 89 salinity profiles including 8 newly conducted salinity measurements. The revised predictive equations consist of easily measured parameters such as the geometry of estuary, tide, friction and the Richardson number. These equations are useful in obtaining the first estimate of salinity distribution in an estuary.
Hydrol. Earth Syst. Sci., 19, 2791-2803, doi:10.5194/hess-19-2791-2015, 2015
Assessment of Halon-1301 as a groundwater age tracer
Summary: We assess the potential of Halon-1301 as a new groundwater age tracer, which had not been assessed in detail. We determine Halon-1301 and infer age in 17 New Zealand groundwater samples and various modern waters. Halon-1301 reliably inferred age in 71% of the sites within 1 SD of the ages inferred from tritium and SF6. The remaining (anoxic) waters show reduced concentrations of Halon-1301 along with even further reduced concentrations of CFCs. The reason(s) for this need to be further assessed.
Hydrol. Earth Syst. Sci., 19, 2775-2789, doi:10.5194/hess-19-2775-2015, 2015
Understanding NMR relaxometry of partially water-saturated rocks
Hydrol. Earth Syst. Sci., 19, 2763-2773, doi:10.5194/hess-19-2763-2015, 2015
Technical Note: A simple generalization of the Brutsaert and Nieber analysis
Summary: We propose a simple modification of the Brutsaert–Nieber analysis of aquifers during a hydrologic recession that allows for the nonzero depth of the adjoining stream to the aquifer to be duly taken into account. This modification can produce significantly different values of the estimated drainable porosity, as found by a simple sensitivity analysis.
Hydrol. Earth Syst. Sci., 19, 2755-2761, doi:10.5194/hess-19-2755-2015, 2015
Large-basin hydrological response to climate model outputs: uncertainty caused by internal atmospheric variability
Summary: Our paper is one of very few studies where the influence of stochastic internal atmospheric variability (IAV) on the hydrological response is analyzed. On the basis of ensemble experiments with GCM and hydrological models, we found, e.g., that averaging over ensemble members filters the stochastic term related to IAV, and that a considerable portion of the simulated trend in annual Lena R. runoff can be explained by the externally forced signal (global SST and SIC changes in our experiments).
Hydrol. Earth Syst. Sci., 19, 2737-2754, doi:10.5194/hess-19-2737-2015, 2015