Comment on "Using groundwater age and hydrochemistry to understand sources and dynamics of nutrient contamination through the catchment into Lake Rotorua, New Zealand" by Morgenstern et al. (2015)
Summary: We comment on “Using groundwater age and hydrochemistry to understand sources and dynamics of nutrient contamination through the catchment into Lake Rotorua, New Zealand” by Morgenstern et al. (2015). They propose that "the only effective way to limit algae blooms and improve lake water quality in such environments is by limiting the nitrate load". We outline four reasons why we believe it is important to limit both phosphorus and nitrogen loads to this iconic lake.
Hydrol. Earth Syst. Sci. Discuss., 12, 10379-10388, doi:10.5194/hessd-12-10379-2015, 2015
Assessment of the influence of bias correction on meteorological drought projections for Poland
Hydrol. Earth Syst. Sci. Discuss., 12, 10331-10377, doi:10.5194/hessd-12-10331-2015, 2015
Evaluation of five hydrological models across Europe and their suitability for making projections under climate change
Summary: The main aims of this paper are the evaluation of five large-scale hydrological models across Europe and the assessment of the suitability of the models for making projections under climate change. While we found large inter-model differences in biases, the skill to simulate interannual variability in discharge did not differ much between the models. Assuming that the skill of a model to simulate interannual variability provides a measure for the model’s ability to make projections under climate
Hydrol. Earth Syst. Sci. Discuss., 12, 10289-10330, doi:10.5194/hessd-12-10289-2015, 2015
Precipitation ensembles conforming to natural variations derived from Regional Climate Model using a new bias correction scheme
Summary: A primary advantage of using model ensembles for climate change impact studies is to represent the uncertainties associated with models through the ensemble spread. Currently, most of the conventional bias correction methods adjust all the ensemble members to one reference observation. As a result, the ensemble spread is degraded during bias correction. However the proposed method is able to correct the bias and conform to the ensemble spread so that the ensemble information can be better used.
Hydrol. Earth Syst. Sci. Discuss., 12, 10261-10287, doi:10.5194/hessd-12-10261-2015, 2015
Quantifying the nutrient flux within a lowland karstic catchment
Summary: In this study, the nutrient flux occurring within the surface and groundwaters of a lowland karst catchment in western Ireland was investigated with the aid of alkalinity sampling and a hydrological model. Results indicated that denitrification within a number of ephemeral lakes is the main process reducing nitrogen concentrations within the turloughs whereas phosphorus loss is thought to occur mostly via sedimentation and subsequent soil deposition.
Hydrol. Earth Syst. Sci. Discuss., 12, 10221-10260, doi:10.5194/hessd-12-10221-2015, 2015
A comparison of the modern Lie scaling method to classical scaling techniques
Summary: This article summarizes the theory and demonstrates the technique of a new scaling method known as the Lie scaling. In the course of applying the method to two example problems, classical notions of dynamical and kinematic scaling are incorporated. The two example problems are: a 2D unconfined groundwater problem in a heterogeneous soil, and a 1D contaminant transport problem. The article concludes with comments on the relative strengths and weaknesses of Lie scaling and classical scaling.
Hydrol. Earth Syst. Sci. Discuss., 12, 10197-10219, doi:10.5194/hessd-12-10197-2015, 2015
Impacts of climate change under CMIP5 RCP scenarios on the streamflow in the Dinder River and ecosystem habitats in Dinder National Park, Sudan
Summary: We assess the impact of future climate change on the Dinder River streamflow-Sudan, and infer its relative possible effects on the Dinder National Park (DNP) ecosystem habitats. Two GCMs from CMIP5 and two statistical downscaling approaches combined with SWAT were used. Climate over the basin will become warmer and wetter and the streamflow will likely increase, accordingly the ecosystems in DNP will be affected positively and promote the ecological restoration of the flora and fauna habitats’.
Hydrol. Earth Syst. Sci. Discuss., 12, 10157-10195, doi:10.5194/hessd-12-10157-2015, 2015
Impact of climate change on groundwater in a confined Mediterranean aquifer
Hydrol. Earth Syst. Sci. Discuss., 12, 10109-10156, doi:10.5194/hessd-12-10109-2015, 2015
Sensitivity analysis of runoff modeling to statistical downscaling models in the western Mediterranean
Summary: This original paper provides guideline to select statistical downscaling methods (SDMs) in climate change impact studies (CCIS) to minimize uncertainty from downscaling. Three SDMs were applied on NCEP reanalysis and two GCMs data values. We then analyzed the sensitivity of the hydrological model to the various downscaled data via five hydrological indicators representing the main features of the hydrograph. Our results enable to select the appropriate SDMs to be used to build climate scenarios.
Hydrol. Earth Syst. Sci. Discuss., 12, 10067-10108, doi:10.5194/hessd-12-10067-2015, 2015
Parameter regionalization of a monthly water balance model for the conterminous United States
Hydrol. Earth Syst. Sci. Discuss., 12, 10023-10066, doi:10.5194/hessd-12-10023-2015, 2015
Investigating effects of different evapotranspiration (ET) schemes on soil water dynamics and ET partitioning: a large lysimeter case of summer maize in a semi-arid environment northwest of China
Summary: The coupled water vapor and heat transport model with two different ET (ETdir, ETind) schemes differ in simulating soil water content and evapotranspiration components while agree well for the simulation of soil temperature. Considering the aerodynamic and surface resistance terms make the ETdir scheme better in simulating soil evaporation especially after irrigation. The interactive effect of crop growth parameters with changing environment play an important role in estimating ET components.
Hydrol. Earth Syst. Sci. Discuss., 12, 9977-10022, doi:10.5194/hessd-12-9977-2015, 2015
Identifying hydrological responses of micro-catchments under contrasting land use in the Brazilian Cerrado
Summary: This study examines the rainfall-runoff processes in micro-catchments in which a main source of variability is the contrasting land use. The study area is located in the Amazonian agricultural frontier, in the Brazilian Cerrado biome, and it aims to fill a gap in the literature concerning the Brazilian Cerrado, and to understand how streamflow and catchment hydrologic regimes are conditioned by microclimate, precipitation pattern, land cover and soil properties, among other catchment properties.
Hydrol. Earth Syst. Sci. Discuss., 12, 9915-9975, doi:10.5194/hessd-12-9915-2015, 2015
Stream flow recession patterns can help unravel the role of climate and humans in landscape co-evolution
Summary: We analyse how stream discharge declines after rain storms. This "recession" behaviour contains information about the capacity of the catchment to hold or release water. Looking at many rivers in Sweden, we were able to link distinct recession regimes to land use and catchment characteristics. Trends in recession behaviour are found to correspond to intensifying agriculture and extensive reforestation. We conclude that both men and nature reorganizes the soil in order to enhance efficiency.
Hydrol. Earth Syst. Sci. Discuss., 12, 9865-9913, doi:10.5194/hessd-12-9865-2015, 2015
Use of cosmic ray neutron sensors for soil moisture monitoring in forests
Summary: Cosmic ray neutron sensors bridge the gap between point-scale measurements of soil moisture and remote sensing applications. We tested 5 distinct methods to calibrate the sensor in a temperate forest environment using different soil moisture weighting approaches and neutron count corrections. While the variable leaf biomass of the deciduous trees had no significant influence on the calibration, it proved necessary to modify the standard calibration method to achieve the best sensor performance.
Hydrol. Earth Syst. Sci. Discuss., 12, 9813-9864, doi:10.5194/hessd-12-9813-2015, 2015
Stochastic or statistic? Comparing flow duration curve models in ungauged basins and changing climates
Summary: We compare a stochastic (process-based) and statistical (data-based) method to predict flow duration curves in ungauged basins, under stationary and non-stationary conditions, and using Nepal as a case study. Both methods worked well in stationary conditions, with performances driven by the main source of runoff heterogeneity (climate vs. recession). The stochastic model worked better under change, and the performance of the statistical model was determined by the resilience of the flow regime.
Hydrol. Earth Syst. Sci. Discuss., 12, 9765-9811, doi:10.5194/hessd-12-9765-2015, 2015
Reviving the "Ganges Water Machine": where and how much?
Summary: Agricultural production in the Ganges River Basin is affected by the water shortage in the dry months while the excess water during the rainy season causes floods in the downstream. Annual total surface runoff generated in the Ganges River Basin is about 298 ± 99 Bm3, and runoff in the monsoon months contribute upto 80% of this total runoff. Comparison of sub-basin-wise surface runoff with the estimated un-met water demand indicated that capturing only a portion of the wet-season runoff would be s
Hydrol. Earth Syst. Sci. Discuss., 12, 9741-9763, doi:10.5194/hessd-12-9741-2015, 2015
Modeling runoff and erosion risk in a~small steep cultivated watershed using different data sources: from on-site measurements to farmers' perceptions
Hydrol. Earth Syst. Sci. Discuss., 12, 9701-9740, doi:10.5194/hessd-12-9701-2015, 2015
Co-evolution of volcanic catchments in Japan
Summary: We derived indices of landscape properties as well as hydrological response and examined their relation with catchment age and climate. We found significant correlation between drainage density and baseflow index with age, but not with climate. We compared our data with data from volcanic catchments in Oregon and could confirm that baseflow index decreases with time, but also discovered that drainage density seems to stabilize after 2M years, after an initial increase due to landscape incision.
Hydrol. Earth Syst. Sci. Discuss., 12, 9655-9700, doi:10.5194/hessd-12-9655-2015, 2015
A framework for testing the use of electric and electromagnetic data to reduce the prediction error of groundwater models
Hydrol. Earth Syst. Sci. Discuss., 12, 9599-9653, doi:10.5194/hessd-12-9599-2015, 2015
Soil–aquifer phenomena affecting groundwater under vertisols: a review
Hydrol. Earth Syst. Sci. Discuss., 12, 9571-9598, doi:10.5194/hessd-12-9571-2015, 2015
Towards systematic planning of small-scale hydrological intervention-based research
Hydrol. Earth Syst. Sci. Discuss., 12, 9489-9569, doi:10.5194/hessd-12-9489-2015, 2015
A quantitative analysis to objectively appraise drought indicators and model drought impacts
Summary: To date, there is little empirical evidence as to which indicator best represents drought impact occurrence for any given region and/or sector. We therefore exploited text-based data from the European Drought Impact report Inventory (EDII) to evaluate drought indicators, empirically determine indicator thresholds, and model drought impacts. A quantitative analysis using Germany and the UK as a testbed proved to be a useful tool for objectively appraising drought indicators.
Hydrol. Earth Syst. Sci. Discuss., 12, 9437-9488, doi:10.5194/hessd-12-9437-2015, 2015
Simulating hydrology with an isotopic land surface model in western Siberia: what do we learn from water isotopes?
Summary: We show that water stable isotopes help constraining key processes in the land surface model ORCHIDEE. We implemented 18O, 2H, δ18O and δD in soil and leaf water in the model, ran it and evaluated results on measured profiles of soil water isotopes ratios. Relevant features of δ18O profiles are relatively well simulated. We show the importance of infiltration pathway and vegetation/bare-soil cover in ORCHIDEE and to which extent we can determine the evaporation/evapotranspiration ratio.
Hydrol. Earth Syst. Sci. Discuss., 12, 9393-9436, doi:10.5194/hessd-12-9393-2015, 2015
Evaluation of global fine-resolution precipitation products and their uncertainty quantification in ensemble discharge simulations
Summary: Six precipitation products, including TRMM3B42, TRMM3B42RT, GLDAS/Noah, APHRODITE, PERSIANN and GSMAP-MVK+, are investigated in the usually-neglected area - northeast China, and a framework to quantify the contributions of uncertainties from precipitation products, hydrological models and their interactions to uncertainty in simulated discharges is developed. It is found that interactions between hydrological models and precipitation products contribute significantly to uncertainty in discharge.
Hydrol. Earth Syst. Sci. Discuss., 12, 9337-9391, doi:10.5194/hessd-12-9337-2015, 2015
Technical Note: Application of artificial neural networks in groundwater table forecasting – a case study in Singapore swamp forest
Summary: This study, for the first time, applies ANN to predict the groundwater table variations in a tropical wetland – the NSSF in Singapore. Surrounding reservoir levels and rainfall are selected as ANN inputs. The limited number of inputs eliminates the data demanding restrictions inherent in the numerical models. The forecast is made at 4 piezometer locations with 3 leading times up to 7 days. The ANN forecast shows promising accuracy with slight decreasing performance when leading time progresses.
Hydrol. Earth Syst. Sci. Discuss., 12, 9317-9336, doi:10.5194/hessd-12-9317-2015, 2015
Subsurface flow mixing in coarse, braided river deposits
Summary: This study: - puts the hydraulic heterogeneity of coarse, braided river deposits in concrete terms, combining geophysics and sedimentological observations; - shows the possible impact of the heterogeneity on the three-dimensional flow field in terms of subsurface flow mixing); - demonstrates that not only the fast subsurface flow paths are important but also the hydraulic head field;
Hydrol. Earth Syst. Sci. Discuss., 12, 9295-9316, doi:10.5194/hessd-12-9295-2015, 2015
Sustainability of water uses in managed hydrosystems: human- and climate-induced changes for the mid-21st century
Summary: We assess the sustainability of planned water uses in complex mesoscale river basins by modeling water demand and availability under climatic and anthropogenic changes. We present an analysis through indicators that relate to water management goals. The impacts of climate projections on both water availability and demand question the water allocations and environmental constraints currently planned for the coming decades.This work brings an essential long-term perspective to water sharing plans.
Hydrol. Earth Syst. Sci. Discuss., 12, 9247-9293, doi:10.5194/hessd-12-9247-2015, 2015
Using geochemical tracers to distinguish groundwater and parafluvial inflows in rivers (the Avon Catchment, SE Australia)
Summary: This paper uses the natural geochemical tracer Rn together with streamflow measurements to differentiate between groundwater inflows to rivers and water that exits the river, flows through the near-river sediments, and subsequently re-enters the river downstream (parafluvial flow). Distinguishing between these two components is important to understanding the water balance and in managing and protecting surface water resources.
Hydrol. Earth Syst. Sci. Discuss., 12, 9205-9246, doi:10.5194/hessd-12-9205-2015, 2015
Investigation of hydrological time series using copulas for detecting catchment characteristics and anthropogenic impacts
Summary: This paper is aiming at detecting the climate change impacts on the hydrological regime from the long term discharge records. A new method for stochastic analysis using copulas, which has the advantage to scrutinize the data independent of marginal, is suggested in this paper. Two measures in the copula domain, one focuses on the asymmetric characteristic of data and the other compares the distances between the copulas, are calculated for 100 years daily discharges and the results are discussed.
Hydrol. Earth Syst. Sci. Discuss., 12, 9157-9203, doi:10.5194/hessd-12-9157-2015, 2015
Determinants of modelling choices for 1-D free-surface flow and erosion issues in hydrology: a review
Summary: This paper investigates the determinants of modelling choices, for 1-D free-surface flow and erosion issues, across multiple spatiotemporal scales. These determinants are sought in the interplay between flow typologies, cross-scale and scale-independent arguments. This review helps modellers positioning their choices with respect to the most frequent practices, within a generic, normative procedure possibly enriched by the community for a comprehensive, updatable image of modelling strategies.
Hydrol. Earth Syst. Sci. Discuss., 12, 9091-9155, doi:10.5194/hessd-12-9091-2015, 2015
HydroSCAPE: a multi-scale framework for streamflow routing in large-scale hydrological models
Summary: In this work we present HydroSCAPE, an innovative, parsimonious, and computationally efficient streamflow routing method based on travel time approach. HydroSCAPE is designed to be easily coupled with climate models, and to preserve the geomorphological dispersion of the river network, independently on the model grid size. This makes HydroSCAPE especially suited for multi-scale applications (from catchment up to continental scale), and to investigate extreme events (e.g. floods).
Hydrol. Earth Syst. Sci. Discuss., 12, 9055-9090, doi:10.5194/hessd-12-9055-2015, 2015
The effect of assimilating satellite derived soil moisture in SiBCASA on simulated carbon fluxes in Boreal Eurasia
Summary: Boreal Eurasia is contains extensive forests, which play an important role in the terrestrial carbon cycle. Droughts can modify this cycle considerably, although very few ground-based observations are available. We test whether satellite-observed soil moisture may be used to improve carbon cycle models in this region. This paper explains when and where this works best. The interpretation of satellite soil moisture is best in summer conditions, and is hampered by snow, ice and ponding.
Hydrol. Earth Syst. Sci. Discuss., 12, 9003-9054, doi:10.5194/hessd-12-9003-2015, 2015
Impact of two different types of El Niño events on runoff over the conterminous United States
Hydrol. Earth Syst. Sci. Discuss., 12, 8977-9002, doi:10.5194/hessd-12-8977-2015, 2015
Spatio-temporal variability of snow water equivalent in the extra-tropical Andes cordillera from a distributed energy balance modeling and remotely sensed snow cover
Summary: We present a high-resolution snow water equivalent estimation for the 2001 - 2014 period over the extratropical Andes Cordillera of Argentina and Chile, the first of its type. The effect of elevation on accumulation is confirmed, although this is less marked in the northern portion of the domain. The 3000-4000 m asl. elevation band contributes the bulk of snowmelt, but the 4000-5000 m asl. band is a significant source and deserves further monitoring and research.
Hydrol. Earth Syst. Sci. Discuss., 12, 8927-8976, doi:10.5194/hessd-12-8927-2015, 2015
Estimation of deep infiltration in unsaturated limestone environments using cave LiDAR and drip count data
Hydrol. Earth Syst. Sci. Discuss., 12, 8891-8925, doi:10.5194/hessd-12-8891-2015, 2015
Adaptation of water resource systems to an uncertain future
Hydrol. Earth Syst. Sci. Discuss., 12, 8853-8889, doi:10.5194/hessd-12-8853-2015, 2015
Modelling socio-hydrological systems: a review of concepts, approaches and applications
Summary: This paper reviews literature surrounding many aspects of socio-hydrological modelling; this includes a background to the subject of socio-hydrology, reasons for modelling, potential applications and concepts that underpin models, as well as describing several modelling techniques and how they may be applied in socio-hydrology.
Hydrol. Earth Syst. Sci. Discuss., 12, 8761-8851, doi:10.5194/hessd-12-8761-2015, 2015
Reviving the Ganges Water Machine: why?
Summary: The Ganges River Basin has abundant surface water and groundwater resources, but the seasonal monsoon causes a mismatch between supply and demand as well as flooding. Addressing this mismatch requires substantial additional storage. Reviving the Ganges Water Machine, long known as use of subsurface storage with accelerated surface-subsurface water exchange, to meet the unmet water demand, ranging from 59 to 119 billion m3, is the most opportune solution to the pending water crises in the Basin.
Hydrol. Earth Syst. Sci. Discuss., 12, 8727-8759, doi:10.5194/hessd-12-8727-2015, 2015
A parsimonious analytical model for simulating multispecies plume migration
Summary: A parsimonious analytical model for predicting the plume behavior of decaying contaminant is presented in this study. The analytical results indicate that the parsimonious analytical solutions are robust and accurate. The solutions are useful for serving as simulation or screening tools for assessing plume behaviors of decaying contaminants including the radionuclides and dissolved chlorinated solvents in groundwater systems.
Hydrol. Earth Syst. Sci. Discuss., 12, 8675-8726, doi:10.5194/hessd-12-8675-2015, 2015
Recent climatic, cryospheric, and hydrological changes over the interior of western Canada: a synthesis and review
Summary: This paper provides an integrated review and up-to-date synthesis of the observed changes in air temperature, precipitation, seasonal snow cover, mountain glaciers, permafrost, freshwater ice cover, and river discharge over the interior of western Canada since the mid or late-20th century. Important long-term observational networks and datasets are described, and qualitative linkages among the changing Earth system components are highlighted.
Hydrol. Earth Syst. Sci. Discuss., 12, 8615-8674, doi:10.5194/hessd-12-8615-2015, 2015
Nitrate sinks and sources as controls of spatio-temporal water quality dynamics in an agricultural headwater catchment
Summary: We quantify the spatio-temporal impact of distinct nitrate sinks and sources on stream network nitrate dynamics in an agricultural headwater. By applying a data-driven modelling approach we are able to fully distinguish between mixing and dilution processes and biogeochemical in-stream removal processes along the stream network. In-stream nitrate removal is estimated by applying a novel transfer coefficient based on energy availability.
Hydrol. Earth Syst. Sci. Discuss., 12, 8577-8614, doi:10.5194/hessd-12-8577-2015, 2015
Examination for robustness of parametric estimators for flood statistics in the context of extraordinary extreme events
Summary: In the last few years to occurence of extraordinary extreme flood events rised the question for a suitable statistical model to describe this flood behaviour and give a possibility for the calculation of high quantiles. Since the occurence of these extreme events in very short time series (less than 100 years) could influence the statistical estimators leading to a too high estimation we want to use robust estimators to give a moderate weighting to these floods. The results are given here.
Hydrol. Earth Syst. Sci. Discuss., 12, 8553-8576, doi:10.5194/hessd-12-8553-2015, 2015
Evaluation of soil moisture downscaling using a simple thermal based proxy – the REMEDHUS network (Spain) example
Summary: 1. Comprehensive evaluation of a simple newly developed downscaling scheme using in-situ measurements from REMEDHUS network. 2. First time to cross compare the performance of the downscaled soil moisture from MODIS and MSG SEVIRI. 3. Evaluate the performance of the downscaled soil moisture at different spatial resolutions. 4.Explore the influence of LST, vegetation index, terrain, clouds, and land cover heterogeneity on the performance of VTCI.
Hydrol. Earth Syst. Sci. Discuss., 12, 8505-8551, doi:10.5194/hessd-12-8505-2015, 2015
Mediterranean irrigation under climate change: more efficient irrigation needed to compensate increases in irrigation water requirements
Summary: At present the Mediterranean region could save 35 % of water by implementing more efficient irrigation and conveyance systems (EICS). By 2080-2090 the region might face an increase in gross irrigation requirements (IR) up to 74 % due to climate change and population growth. EICS may be able to compensate to some degree these increases. Most countries from the Northern and Eastern Mediterranean have a high risk of not being able to meet future IR due to water scarcity.
Hydrol. Earth Syst. Sci. Discuss., 12, 8459-8504, doi:10.5194/hessd-12-8459-2015, 2015
The Normalized Difference Infrared Index (NDII) as a proxy for soil moisture storage in hydrological modelling
Summary: We demonstrated that the readily available NDII Remote Sensing product is a very useful and accurate proxi for moisture storage in the root zone of vegetation. We compared the temporal variation of the NDII with the root zone storage in a hydrological model of 8 catchments in the Upper Ping river in Thailand, yielding very good results. Having a reliable NDII product that can help us to estimate the actual moisture storage in catchments is a major contribution to prediction in ungauged basins.
Hydrol. Earth Syst. Sci. Discuss., 12, 8419-8457, doi:10.5194/hessd-12-8419-2015, 2015
Analytical approach for determining the mean water level profile in an estuary with substantial fresh water discharge
Summary: In this paper, an analytical model for tide-river dynamics has been used to understand the influence of tide and fresh water discharge on the rise of mean water level along the estuary, which remains poorly understood. It is shown that the mean water level is influenced primarily by the tide-river interaction in the tide-dominated region, while it is mainly controlled by the river flow in the upstream part of the estuary.
Hydrol. Earth Syst. Sci. Discuss., 12, 8381-8417, doi:10.5194/hessd-12-8381-2015, 2015
High-frequency monitoring reveals nutrient sources and transport processes in an agriculture-dominated lowland water system
Hydrol. Earth Syst. Sci. Discuss., 12, 8337-8380, doi:10.5194/hessd-12-8337-2015, 2015
A question driven socio-hydrological modeling process
Summary: The paper, entitled "A Question Driven Socio-hydrological Modeling Process", presents a new process for developing conceptual models of coupled socio-hydrological systems. This modeling process is demonstrated by developing a model of a hypothetical system based on a hypothesis linking per capita water demand changes to supply reliability. The resulting model illustrates both the modeling process and the relevance of the hypothesis for reservoir operations policy.
Hydrol. Earth Syst. Sci. Discuss., 12, 8289-8335, doi:10.5194/hessd-12-8289-2015, 2015
A century scale human-induced hydrological and ecological changes of wetlands of two large river basins in Australia (Murray) and China (Yangtze): development of an adaptive water resource management framework
Hydrol. Earth Syst. Sci. Discuss., 12, 8247-8287, doi:10.5194/hessd-12-8247-2015, 2015
The use of semi-structured interviews for the characterisation of farmer irrigation practices
Summary: Semi-structured interviews provide an effective and efficient way of collecting qualitative and quantitative data on water use practices. Interviews are organised around a topic guide, which help lead the conversation while allowing sufficient opportunity to identify issues previously unknown to the researcher. The use of semi-structured interviews could significantly and quickly improve insight on water resources, leading to more realistic future management options and increased water security.
Hydrol. Earth Syst. Sci. Discuss., 12, 8221-8246, doi:10.5194/hessd-12-8221-2015, 2015
On the propagation of diel signals in river networks using analytic solutions of flow equations
Summary: We design and implement a theoretical experiment to show that, under low flow conditions, observed streamflow discrepancies between early and late summer can be attributed to different flow velocities in the river network. By developing an analytic solution to represent flow along a given river network, we emphasize the dependence of streamflow amplitude and time delay on the geomorphology of the network. We also simulate using a realistic river network to highlight the effects of scale.
Hydrol. Earth Syst. Sci. Discuss., 12, 8175-8220, doi:10.5194/hessd-12-8175-2015, 2015
Data assimilation in integrated hydrological modelling in the presence of observation bias
Hydrol. Earth Syst. Sci. Discuss., 12, 8131-8173, doi:10.5194/hessd-12-8131-2015, 2015
Assessing various drought indicators in representing drought in boreal forests in Finland
Hydrol. Earth Syst. Sci. Discuss., 12, 8091-8129, doi:10.5194/hessd-12-8091-2015, 2015
Time-series of tritium, stable isotopes and chloride reveal short-term variations in groundwater contribution to a stream
Summary: The transit time of water is a key indicator of hydrological processes at the catchment scale. Our results suggest that the use of tritium time-series in streamwater can be highly valuable for assessing the temporal variations in the transit time of older groundwater contributions to streamflow. We also show that shortly after high flow events, the transit time of the old water fraction increases and tends to approach the groundwater residence time.
Hydrol. Earth Syst. Sci. Discuss., 12, 8035-8089, doi:10.5194/hessd-12-8035-2015, 2015
A rainfall design method for spatial flood risk assessment: considering multiple flood sources
Summary: In this paper, a rainfall design method for spatial flood risk assessment, which considers the joint effects of multiple flood sources, is proposed. The concept of critical rainfall duration determined by the concentration time of flooding is introduced to connect response characteristics of different flood sources with rainfall. A copula method is then adopted to capture the correlation of rainfall amount with different critical rainfall duration.
Hydrol. Earth Syst. Sci. Discuss., 12, 8005-8033, doi:10.5194/hessd-12-8005-2015, 2015
The impact of near-surface soil moisture assimilation at subseasonal, seasonal, and inter-annual time scales
Summary: A soil moisture assimilation experiment is evaluated separately at sub-seasonal, seasonal, and inter-annual time scales. In addition to previously reported improvements in sub-seasonal scale soil moisture, it is show that such an assimilation can also improve the model soil moisture at seasonal and inter-annual time scales, demonstrating the potential for near-surface soil moisture assimilation to improve model representation of important long term events, such as droughts.
Hydrol. Earth Syst. Sci. Discuss., 12, 7971-8004, doi:10.5194/hessd-12-7971-2015, 2015
Influence of climate variability on water partitioning and effective energy and mass transfer (EEMT) in a semi-arid critical zone
Hydrol. Earth Syst. Sci. Discuss., 12, 7933-7969, doi:10.5194/hessd-12-7933-2015, 2015
Soil storage influences climate–evapotranspiration interactions in three western United States catchments
Hydrol. Earth Syst. Sci. Discuss., 12, 7893-7931, doi:10.5194/hessd-12-7893-2015, 2015
Technical Note: Testing an improved index for analysing storm nutrient hysteresis
Summary: This paper examines the current methodologies for quantifying storm behaviour through hysteresis analysis, and explores a new method. Each method is systematically tested and the impact on the results is examined. Recommendations are made regarding the most effective method of calculating a hysteresis index. This new method allows storm hysteresis behaviour to be directly compared between storms, parameters and catchments, meaning it has wide application potential in water quality research.
Hydrol. Earth Syst. Sci. Discuss., 12, 7875-7892, doi:10.5194/hessd-12-7875-2015, 2015
Effects of cultivation and reforestation on suspended sediment concentrations: a case study in a mountainous catchment in China
Summary: Whether changes in land use/cover alter soil loss by changing the runoff volume or by changing the suspended sediment concentration (SSC) has received little attention. This paper presents suspended sediment concentration dynamics and the relationship between SSC and discharge (Q) in the 8973-km2 Du catchment and its sub-catchment (4635 km2). ANOVA indicated that the SSC did not significantly change under cultivation for low and moderate flows, but was significantly different under high flow.
Hydrol. Earth Syst. Sci. Discuss., 12, 7583-7614, doi:10.5194/hessd-12-7583-2015, 2015
Estimating evapotranspiration with thermal UAV data and two source energy balance models
Summary: 1) Thermal images collected with an Unmanned Aerial Vehicle (UAV) are applied to two-source energy balance models in order to estimate evapotranspiration in very high resolution. 2) Thermal images are successfully mosaicked and processed into model input. 3) The two-source energy balance models (TSEB-PT and DTD) are validated during overcast weather conditions. 4) The DTD model provide results in best agreement with Eddy covariance data.
Hydrol. Earth Syst. Sci. Discuss., 12, 7469-7502, doi:10.5194/hessd-12-7469-2015, 2015
Future changes in flash flood frequency and intensity of the Tha Di River (Thailand) based on rainfall–runoff modeling and advanced delta change scaling
Summary: HBV-Light was calibrated and validated with simultaneously recorded discharge and precipitation data of the years 1989–2009. Results show, that the raw Regional Climate Model series overestimate precipitation sums by the factor of two or more. HBV modeling shows an increase for the yearly average cumulative precipitation until the end of the century between 10-30%. The dry season is likely to become longer and drier.
Hydrol. Earth Syst. Sci. Discuss., 12, 7327-7352, doi:10.5194/hessd-12-7327-2015, 2015
High-end climate change impact on European water availability and stress: exploring the presence of biases
Summary: A set of the new Euro-CORDEX projections is used to examine the impact of high-end scenarios on water availability and stress at pan-European scale. Drought climatology is investigated for five major European basins along with the impact of +2C versus +4C warming. The effect of bias correction is also examined. The selection of the observational dataset used for bias adjustment has an impact on the projected signal that could be of the same order of magnitude as the selection of the RCM.
Hydrol. Earth Syst. Sci. Discuss., 12, 7267-7325, doi:10.5194/hessd-12-7267-2015, 2015
Rainfall erosivity in subtropical catchments and implications for erosion and particle-bound contaminant transfer: a case-study of the Fukushima region
Summary: Characterizing rainfall erosivity in the Fukushima fallout-impacted region is important for predicting radiocesium behaviour. The majority of rainfall (60 %) and rainfall erosivity (86 %) occurs between June and October. Understanding the impact of typhoons will be important for managing sediment and sediment-bound contaminant transfers in the Fukushima region and other subtropical regions impacted by cyclonic activity.
Hydrol. Earth Syst. Sci. Discuss., 12, 7225-7266, doi:10.5194/hessd-12-7225-2015, 2015
Accounting for three sources of uncertainty in ensemble hydrological forecasting
Hydrol. Earth Syst. Sci. Discuss., 12, 7179-7223, doi:10.5194/hessd-12-7179-2015, 2015
Effectiveness of a regional model calibrated to different parts of a flow regime in regionalisation
Summary: - Model deficiencies were identified through analysing the non-stationarity nature under different climate conditions. - Model deficiencies influenced on the identification of the relationship between the model parameters and the catchment attributes. - The parameter uncertainty in regionalisation was reduced through improving identifiability of the model parameters representing the different behaviour of the catchment. - This approach is applicable to the catchments in the monsoon areas.
Hydrol. Earth Syst. Sci. Discuss., 12, 7057-7098, doi:10.5194/hessd-12-7057-2015, 2015
Spatial characteristics of severe storms in Hong Kong
Summary: A storm may cause serious damage to infrastructures and public safety. The objective of this paper is to quantify the spatial characteristics of three severe storms in Hong Kong. The spatial distribution of the maximum rolling rainfall is represented by a rotated ellipsoid trend surface and a random field of residuals. The principal directions of the surface trend are between 25° and 45°. The scales of fluctuation of the residuals along eight directions are found between 5 km and 25 km.
Hydrol. Earth Syst. Sci. Discuss., 12, 6981-7021, doi:10.5194/hessd-12-6981-2015, 2015
Development and verification of a real-time stochastic precipitation nowcasting system for urban hydrology in Belgium
Summary: The Short-Term Ensemble Prediction System (STEPS) is implemented in real-time at the Royal Meteorological Institute of Belgium (STEPS-BE). The idea behind STEPS is to quantify the forecast uncertainty by adding stochastic perturbations to the deterministic extrapolation of radar images. In this paper we present the deterministic, probabilistic and ensemble verification of STEPS-BE forecasts using four precipitation cases that caused sewer system overflow in the cities of Leuven and Ghent.
Hydrol. Earth Syst. Sci. Discuss., 12, 6831-6879, doi:10.5194/hessd-12-6831-2015, 2015
Investigating the impact of land-use land-cover change on Indian summer monsoon daily rainfall and temperature during 1951–2005 using a regional climate model
Summary: Regional climate model (RegCM4) simulations demonstrate that part of the observed decrease in moderate rainfall events during summer monsoon season over central India from 1951 to 2005 is attributed to anthropogenically induced land-use land-cover change (LULCC). LULCC also explains a warming in the daily mean and maximum temperature by 1-1.2oC, that is comparable with the observed increasing trend. This study shows the importance of LULCC in the context of regional climate change over India.
Hydrol. Earth Syst. Sci. Discuss., 12, 6575-6633, doi:10.5194/hessd-12-6575-2015, 2015
Linking biogeochemistry to hydro-geometrical variability in tidal estuaries: a generic modeling approach
Summary: A generic estuarine model is applied to three idealized tidal estuaries representing the main hydro-geometrical estuarine classes. The study provides insight on the estuarine biogeochemical dynamics, in particular the air-water CO2 flux, as well as on the potential response to future environmental changes and to uncertainties in model parameter values. We believe that our approach could help improving upscaling strategies to better integrate estuaries in regional/global biogeochemical studies.
Hydrol. Earth Syst. Sci. Discuss., 12, 6351-6435, doi:10.5194/hessd-12-6351-2015, 2015
Land-use changes reinforce the impacts of climate change on annual runoff dynamics in a southeast China coastal watershed
Summary: The L-R diagram was developed to reveal that land-use changes has reinforced the impact of climate changes on annual runoff dynamic in a Southeast China coastal watershed. Deforestation played significant role to generate overflow runoff in a watershed during heavy precipitation. In contrast, reforestation enabled watershed to store more water in a catchment during dry year. This study inferred that severe drought and flood in the future cannot be fully addressed as an impact of climate changes.
Hydrol. Earth Syst. Sci. Discuss., 12, 6305-6325, doi:10.5194/hessd-12-6305-2015, 2015
Estimation of flood warning runoff thresholds in ungauged basins with asymmetric error functions
Hydrol. Earth Syst. Sci. Discuss., 12, 6011-6041, doi:10.5194/hessd-12-6011-2015, 2015
On the spatial organization of the ridge slough patterned landscape
Hydrol. Earth Syst. Sci. Discuss., 12, 2975-3010, doi:10.5194/hessd-12-2975-2015, 2015