Temperature and rainfall estimates for past 18 000 years in Owens Valley, California with a coupled catchment–lake model
Summary: This study simulates paleolake extent in Owens Valley, California in the last 18ka. A coupled catchment-lake model is developed which is capable of accurately simulating lake extent as a function of modern climate and paleoclimate. Through these simulations, the paleoclimate information including annual precipitation and temperature can be quantitatively estimated against field evidence in a catchment-lake hydrologic system.
Hydrol. Earth Syst. Sci. Discuss., 12, 6505-6539, doi:10.5194/hessd-12-6505-2015, 2015
Estimating spatially distributed soil water content at small watershed scales based on decomposition of temporal anomaly and time stability analysis
Summary: Spatiotemporal SWC was decomposed into into three terms (spatial forcing, temporal forcing, and interactions between spatial and temporal forcing) for near surface and root zone; Empirical orthogonal function indicated that underlying patterns exist in the interaction term at small watershed scales; Estimation of spatially distributed SWC benefits from decomposition of the interaction term; The suggested decomposition of SWC with time stability analysis has potential in SWC downscaling.
Hydrol. Earth Syst. Sci. Discuss., 12, 6467-6503, doi:10.5194/hessd-12-6467-2015, 2015
Impacts of grid resolution on surface energy fluxes simulated with an integrated surface-groundwater flow model
Hydrol. Earth Syst. Sci. Discuss., 12, 6437-6466, doi:10.5194/hessd-12-6437-2015, 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
Enhancing the T-shaped learning profile when teaching hydrology using data, modeling, and visualization activities
Hydrol. Earth Syst. Sci. Discuss., 12, 6327-6350, doi:10.5194/hessd-12-6327-2015, 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
High frequency monitoring of water fluxes and nutrient loads to assess the effects of controlled drainage on water storage and nutrient transport
Summary: Controlled drainage has been recognized as an effective option to optimize soil moisture conditions for agriculture and to reduce unnecessary losses of fresh water and nutrients. For a grassland field in The Netherlands we measured the changes in the field water and solute balance after introducing controlled drainage. We concluded that controlled drainage reduced the drain discharge and increased the groundwater storage in the field, but did not have clear positive effects for water quality.
Hydrol. Earth Syst. Sci. Discuss., 12, 6275-6304, doi:10.5194/hessd-12-6275-2015, 2015
Determining the stable isotope composition of pore water from saturated and unsaturated zone core: improvements to the direct vapor equilibration laser spectroscopy method
Hydrol. Earth Syst. Sci. Discuss., 12, 6241-6274, doi:10.5194/hessd-12-6241-2015, 2015
Hydrologic extremes – an intercomparison of multiple gridded statistical downscaling methods
Summary: Seven gridded statistical downscaling methods are tested for strength in simulating climate and hydrologic extremes. A recently developed technique, which is a post-processed version of Bias Corrected Constructed Analogues where the final bias correction is based on the Bias Corrected Climate Imprint method, is shown to be an especially strong method for hydrologic extremes versus other more commonly applied methods including the popular Bias Corrected Spatial Disaggregation method.
Hydrol. Earth Syst. Sci. Discuss., 12, 6179-6239, doi:10.5194/hessd-12-6179-2015, 2015
Assessing changes on urban flood vulnerability through mapping land use from historical information
Summary: This paper presents an appraisal of flood vulnerability of two French cities, Besançon and Moissac, which have been largely impacted by two ancient major floods (respect. in January 1910 and March 1930). An analysis of historical sources allows the mapping of land use and occupation within the flood extent of the two historical floods, both in past and present contexts. It gives an insight of the complexity of flood risk evolution, at a local scale.
Hydrol. Earth Syst. Sci. Discuss., 12, 6151-6177, doi:10.5194/hessd-12-6151-2015, 2015
In-situ unsaturated zone stable water isotope (2H and 18O) measurements in semi-arid environments using tunable off-axis integrated cavity output spectroscopy
Hydrol. Earth Syst. Sci. Discuss., 12, 6115-6149, doi:10.5194/hessd-12-6115-2015, 2015
Initial assessment of a multi-model approach to spring flood forecasting in Sweden
Summary: New approaches to spring flood forecasting, that reflect the latest developments with respect to analysis and modelling on seasonal time scales, are presented and evaluated. Three main approaches, represented by specific methods, are evaluated in spring-flood hindcasts for three Swedish rivers over a 10-year period. When combining all forecasts in a weighted multi-model approach, a mean improvement over all locations and lead times of nearly 10% was indicated, as compared with today's approach.
Hydrol. Earth Syst. Sci. Discuss., 12, 6077-6113, doi:10.5194/hessd-12-6077-2015, 2015
Satellite signal shows storage-unloading subsidence in North China
Summary: There has been excessive (surface and subsurface) water use in North China for several decades now. Why this has enhanced productivity, it has its environmental consequences. This study is a novel use of GRACE and various hydro-geodetic data in analyzing storage depletion subsidence in North China, which condition further reduces water storage. The concurrence of storage loss and land subsidence threatens social stability.
Hydrol. Earth Syst. Sci. Discuss., 12, 6043-6075, doi:10.5194/hessd-12-6043-2015, 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
Evaluating the utility of satellite soil moisture retrievals over irrigated areas and the ability of land data assimilation methods to correct for unmodeled processes
Hydrol. Earth Syst. Sci. Discuss., 12, 5967-6009, doi:10.5194/hessd-12-5967-2015, 2015
The cost of ending groundwater overdraft on the North China Plain
Hydrol. Earth Syst. Sci. Discuss., 12, 5931-5966, doi:10.5194/hessd-12-5931-2015, 2015
Influence of environmental factors on spectral characteristic of chromophoric dissolved organic matter (CDOM) in Inner Mongolia Plateau, China
Hydrol. Earth Syst. Sci. Discuss., 12, 5895-5929, doi:10.5194/hessd-12-5895-2015, 2015
Spatiotemporal variability of oxygen isotope compositions in three contrasting glacier river catchments in Greenland
Hydrol. Earth Syst. Sci. Discuss., 12, 5841-5893, doi:10.5194/hessd-12-5841-2015, 2015
South Asia river flow projections and their implications for water resources
Summary: South Asia is a highly variable region where there is concern over water and food security. The simulations presented suggest an increasing trend in water resources, in some cases almost doubling by the end of the century although this is masked by the large annual variability of river flows for this region. Future peak river flows still occur during the Monsoon period, with a tendancy for reduced frequency of lowest flows and increased magnitude of highest flows across the selected locations.
Hydrol. Earth Syst. Sci. Discuss., 12, 5789-5840, doi:10.5194/hessd-12-5789-2015, 2015
Correction of real-time satellite precipitation with satellite soil moisture observations
Hydrol. Earth Syst. Sci. Discuss., 12, 5749-5787, doi:10.5194/hessd-12-5749-2015, 2015
Effective damage zone volume of fault zones and initial salinity distribution determine intensity of shallow aquifer salinization in geological underground utilization
Summary: The degree of shallow aquifer salinization triggered by fluid injection into deeper brine-bearing aquifers and brine upward migration through hydraulically conductive faults strongly depends on the regional depth of the freshwater-saltwater boundary, since displaced brines originate only from the upper fault damage zones in the study area. The highest local salinity increase in shallow aquifers occurs in case of closed model boundaries and low fault damage zone volumes.
Hydrol. Earth Syst. Sci. Discuss., 12, 5703-5748, doi:10.5194/hessd-12-5703-2015, 2015
The effect of empirical-statistical correction of intensity-dependent model errors on the climate change signal
Summary: The effect of empirical-statistical bias correction methods like quantile mapping (QM) on the simulated climate change signals (CCS) is currently strongly discussed and is often regarded as deficiency of bias correction methods. We demonstrate that, quite the contrary, QM can lead to an improved CCS and has also the potential to serve as an empirical constraint on model uncertainty in climate projections.
Hydrol. Earth Syst. Sci. Discuss., 12, 5671-5701, doi:10.5194/hessd-12-5671-2015, 2015
Assessing the quality of Digital Elevation Models obtained from mini-Unmanned Aerial Vehicles for overland flow modelling in urban areas
Summary: Precise and detailed DEMs are essential to accurately predict overland flow in urban areas. In this this study we evaluated whether DEMs generated from UAV imagery are suitable for urban drainage overland flow modelling. Specifically, fourteen UAV flights were conducted to assess the influence of four different flight parameters on the quality of generated DEMs. In addition, we compared the best quality UAV DEM to a conventional LiDAR-based DEM; the two DEMs are of comparable quality.
Hydrol. Earth Syst. Sci. Discuss., 12, 5629-5670, doi:10.5194/hessd-12-5629-2015, 2015
Biogeochemical processes controlling density stratification in an iron-meromictic lake
Hydrol. Earth Syst. Sci. Discuss., 12, 5601-5628, doi:10.5194/hessd-12-5601-2015, 2015
Joint inference of groundwater-recharge and hydraulic-conductivity fields from head data using the Ensemble-Kalman filter
Summary: Groundwater recharge and hydraulic conductivity are both important properties of a groundwater model. However, an erroneous conductivity field can be compensated by a false recharge field to construct the same type of hydraulic head observations. In this work we show that prior knowledge is very important when estimating parameter fields from ambiguous data (such as head observations). If the prior information is reasonable, the joint parameter estimation can be possible.
Hydrol. Earth Syst. Sci. Discuss., 12, 5565-5599, doi:10.5194/hessd-12-5565-2015, 2015
Review and classification of indicators of green water availability and scarcity
Summary: The paper draws attention to the fact that green water (soil moisture directly returning to the atmosphere as evaporation) is a scarce resource, because its availability is limited and there are competing demands for green water. Around 80 indicators of green water availability and scarcity are reviewed and classified. Future research directions to develop operational green water scarcity indicators, that can broaden the scope of water scarcity assessments, are discussed.
Hydrol. Earth Syst. Sci. Discuss., 12, 5519-5564, doi:10.5194/hessd-12-5519-2015, 2015
Sensitivity of water scarcity events to ENSO driven climate variability at the global scale
Summary: Freshwater shortage is one of the most important risks, partially driven by climate variability. Here we present a first global scale sensitivity assessment of water scarcity events to El Niño-Southern Oscillation, the most dominant climate variability signal. Given the found correlations, covering a large share of the global land area, and seen the developments of water scarcity impacts under changing socioeconomic conditions, we show that there is large potential for ENSO-based risk reduction.
Hydrol. Earth Syst. Sci. Discuss., 12, 5465-5517, doi:10.5194/hessd-12-5465-2015, 2015
Transit times from rainfall to baseflow in headwater catchments estimated using tritium: the Ovens River, Australia
Summary: This study documents the age of river water in the upper parts of catchments using radioactive tracers (tritium). River water in the upper Ovens Valley (Australia) is several years to decades old and water from different parts of the catchment (e.g., soil, regolith, and groundwater) is mobilised at different flow conditions. The results indicate that these rivers are buffered against short term climate variability but are susceptible to longer-term climate and land use changes.
Hydrol. Earth Syst. Sci. Discuss., 12, 5427-5463, doi:10.5194/hessd-12-5427-2015, 2015
Accounting for dependencies in regionalized signatures for predictions in ungauged catchments
Summary: The absence of flow data to calibrate hydrologic models may reduce the ability of such models to reliably inform water resources management. To address this limitation, it is common to condition hydrological model parameters on regionalized signatures. In this study, we justify the inclusion of larger sets of signatures in the regionalization procedure if their error correlations are formally accounted for and thus enables a more complete use of all available information.
Hydrol. Earth Syst. Sci. Discuss., 12, 5389-5426, doi:10.5194/hessd-12-5389-2015, 2015
Closing the water balance with cosmic-ray soil moisture measurements and assessing their spatial variability within two semiarid watersheds
Hydrol. Earth Syst. Sci. Discuss., 12, 5343-5388, doi:10.5194/hessd-12-5343-2015, 2015
Regionalisation of groundwater droughts using hydrograph classification
Summary: To improve the design of drought monitoring networks and water resource management during episodes of drought, there is a need for a better understanding of spatial variations in the response of aquifers to major meteorological droughts. This paper is the first to describe a suite of methods to quantify such variations. Using an analysis of groundwater level data for a case study from the UK, the influence of catchment characteristics on the varied response of groundwater to droughts is explored
Hydrol. Earth Syst. Sci. Discuss., 12, 5293-5341, doi:10.5194/hessd-12-5293-2015, 2015
Assessing the impact of climate variability and human activity to streamflow variation
Summary: This study investigates the impact of climate variability and human activity to streamflow variation by using an elasticity-based method, calibrated TOPMODEL and VIC hydrologic models. The results from the three methods show that the estimates of climate variability impacts from the hydrological models are similar to those from the elasticity-based method, and the decreased streamflow was mainly affected by human activities. We made a comparison among three different attributing approaches.
Hydrol. Earth Syst. Sci. Discuss., 12, 5251-5291, doi:10.5194/hessd-12-5251-2015, 2015
Long-term effects of climate and land cover change on freshwater provision in the tropical Andes
Summary: Andean catchments play a key role in the provision of freshwater resources. The development of mega-cities in the Inter-Andean valleys raises severe concerns about growing water scarcity. Our study is one of the first long-term (1970s-now) analyses of the role of land cover and climate change on provision and regulation of streamflow in the Tropical Andes. Given the non-stationary character of hydrometeorological time series, we apply novel techniques based on empirical mode decomposition.
Hydrol. Earth Syst. Sci. Discuss., 12, 5219-5250, doi:10.5194/hessd-12-5219-2015, 2015
Identification of spatiotemporal patterns of biophysical droughts in semi-arid region – a case study of the Karkheh river basin in Iran
Summary: This study identified historical patterns of meteorological, hydrological, and agricultural droughts in the Karkheh River Basin in Iran. The SWAT model was used to obtain the variables required for calculating drought indices. Five meteorological droughts were identified, of which four corresponded with the hydrological droughts with 1-3 month lag. The meteorological droughts corresponded with the agricultural droughts during dry months, while the latter lasted for a longer time.
Hydrol. Earth Syst. Sci. Discuss., 12, 5187-5217, doi:10.5194/hessd-12-5187-2015, 2015
Evaluation of a multi-satellite soil moisture product and the Community Land Model 4.5 simulation in China
Summary: In this work, we investigated the performances of a microwave-based merging satellite product (ECV-SM) and the CLM4.5 simulation in China using twenty years of in situ soil moisture observations from 308 stations. CLM4.5 produces better temporal variation of surface soil moisture; ECV-SM has a low bias, but shows a weak correlation; ECV-SM is more likely to be superior in semi-arid regions.
Hydrol. Earth Syst. Sci. Discuss., 12, 5151-5186, doi:10.5194/hessd-12-5151-2015, 2015
Optimality and inference in hydrology from entropy production considerations: synthetic hillslope numerical experiments
Hydrol. Earth Syst. Sci. Discuss., 12, 5123-5149, doi:10.5194/hessd-12-5123-2015, 2015
Trends in West African floods: a comparative analysis with rainfall and vegetation indices
Hydrol. Earth Syst. Sci. Discuss., 12, 5083-5121, doi:10.5194/hessd-12-5083-2015, 2015
Creating long term gridded fields of reference evapotranspiration in Alpine terrain based on a re-calibrated Hargreaves method
Summary: Gridded fields of daily max. and min. Temperatures for the Austrian domain are used to calculate ET0 based on a re-calibrated Hargreaves method. Newly derived, station based calibration parameters, with Penman-Monteith ET0 as a reference, show a distinct altitude and seasonal dependence. Theses features are used to interpolate the new calibration values in space and time onto the temperature grids. The ET0 is then calculated based on the entire gridded temperature data starting back in 1961.
Hydrol. Earth Syst. Sci. Discuss., 12, 5055-5082, doi:10.5194/hessd-12-5055-2015, 2015
Integrated water system simulation by considering hydrological and biogeochemical processes: model development, parameter sensitivity and autocalibration
Summary: We extended a semi-distributed hydrological model (TVGM) to an integrated water system model by coupling multiple water-related processes in hydrology, biogeochemistry, water quality and ecology, and considering the interference of human activities. The parameter sensitivity and autocalibration modules were developed to improve the simulation efficiency. The extended model was applied in the Shaying River Catchment, which is a highly regulated and heavily polluted region in China.
Hydrol. Earth Syst. Sci. Discuss., 12, 4997-5053, doi:10.5194/hessd-12-4997-2015, 2015
Rainfall erosivity estimation based on rainfall data collected over a range of temporal resolutions
Hydrol. Earth Syst. Sci. Discuss., 12, 4965-4996, doi:10.5194/hessd-12-4965-2015, 2015
Estimation of crop water requirements: extending the one-step approach to dual crop coefficients
Hydrol. Earth Syst. Sci. Discuss., 12, 4933-4963, doi:10.5194/hessd-12-4933-2015, 2015
A method for calculating the duration and intensity of salt intrusions: the Yangtze River estuary
Summary: This paper demonstrates a method for calculating the probability of long duration salt intrusions in the Yangtze estuary. The relationship between river discharge and the intensity and duration of saline intrusions is shown to be probabilistic and continuous. For periods like 1950–2014, in a quarter of years saline intrusions (chlorinity ≥ 250 mg / L) of at least 30 days have a one in ten chance of occurring. Intrusions that can disrupt the supply of water to local residents are not rare.
Hydrol. Earth Syst. Sci. Discuss., 12, 4909-4932, doi:10.5194/hessd-12-4909-2015, 2015
Annual canopy interception at artificial lowland tropical forest
Summary: A study has developed a simple model to estimate annual interception loss with temporal resolution effects. The model required minimum input and the amount of the interception loss from an artificial lowland tropical forest was determine with this model. The interception values has been compared with results calculated using original Gash model, modified Gash model and measured data. The findings show that the model can be applied to estimate the interception loss with 0.18 to 2.71% differences.
Hydrol. Earth Syst. Sci. Discuss., 12, 4879-4907, doi:10.5194/hessd-12-4879-2015, 2015
A review of applications of satellite SAR, optical, altimetry and DEM data for surface water modelling, mapping and parameter estimation
Summary: Hydrological data collection is a challenge for the scientific community especially as some events e.g. floods occur in un-gauged rivers or infrequently. Some of such events are however recorded by satellites. Using satellite remote sensing in estimating surface water parameters has its limitations but recent improvements in sensor specifications, expansion in research methods and knowledge of satellite data has increased its utilization The review is on modelling, mapping with RS
Hydrol. Earth Syst. Sci. Discuss., 12, 4857-4878, doi:10.5194/hessd-12-4857-2015, 2015
Effects of mountain agriculture on nutrient cycling at upstream watersheds
Summary: We summarized the findings below: 1. The mountain watersheds are vulnerable to agriculture expansion. 2. Proper spatial configuration of agricultural lands in mountain watersheds can mitigate the impact of agriculture on NO3- output by 70%. 3. The re-constructed element fluxes for the watersheds indicate excessive leaching of N and P, and additional loss of N to the atmosphere via volatilization and denitrification, which likely resulted from excessive fertilizer use.
Hydrol. Earth Syst. Sci. Discuss., 12, 4785-4811, doi:10.5194/hessd-12-4785-2015, 2015
Reconciling high altitude precipitation in the upper Indus Basin with glacier mass balances and runoff
Hydrol. Earth Syst. Sci. Discuss., 12, 4755-4784, doi:10.5194/hessd-12-4755-2015, 2015
Quantifying energy and water fluxes in dry dune ecosystems of the Netherlands
Summary: This study explores the magnitude of energy and water fluxes in an inland dune ecosystem in the Netherlands. We parameterized the Penman-Monteith evapotranspiration model for four different surfaces: bare sand, moss, grass and heather. The knowledge presented in this paper will help improve the simulations of water recharge in sand dunes by hydrological models, and allow quantifying the cost and benefit of nature conservation in terms of groundwater recharge.
Hydrol. Earth Syst. Sci. Discuss., 12, 4541-4594, doi:10.5194/hessd-12-4541-2015, 2015
Spatial and temporal runoff processes in the degraded Ethiopian Highlands: the Anjeni Watershed
Hydrol. Earth Syst. Sci. Discuss., 12, 4387-4411, doi:10.5194/hessd-12-4387-2015, 2015
Uncertainty analysis for evaluating the accuracy of snow depth measurements
Hydrol. Earth Syst. Sci. Discuss., 12, 4157-4190, doi:10.5194/hessd-12-4157-2015, 2015
Climatological characteristics of raindrop size distributions within a topographically complex area
Hydrol. Earth Syst. Sci. Discuss., 12, 4005-4045, doi:10.5194/hessd-12-4005-2015, 2015
Stochastic approach to analyzing the uncertainties and possible changes in the availability of water in the future based on a climate change scenario
Summary: The objective of this study was to analyze the changes and uncertainties related to water availability in the future, in the Ijuí river basin (south of Brazil), using a stochastic approach. In general the results showed a trend to increased flows. It can be concluded that there is a tendency to increase the hydrological variability during the period between 2011-2040, which indicates the possibility of occurrence of time series with more marked periods of droughts and floods.
Hydrol. Earth Syst. Sci. Discuss., 12, 3787-3846, doi:10.5194/hessd-12-3787-2015, 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
5 year radar-based rainfall statistics: disturbances analysis and development of a post-correction scheme for the German radar composite
Hydrol. Earth Syst. Sci. Discuss., 12, 1765-1808, doi:10.5194/hessd-12-1765-2015, 2015
Spatially-distributed influence of agro-environmental factors governing nitrate fate and transport in an irrigated stream-aquifer system
Summary: Nitrate contamination in agricultural groundwater systems is a concern in many regions worldwide. In this study, a model is applied to a regional-scale irrigated stream-aquifer system to identify the system inputs and processes that govern nitrate fate and transport at multiple scales: for the entire study region, for spatial areas irrigated by individual canals, and for individual cultivated fields. Results can be used to guide the localized application of best management practices.
Hydrol. Earth Syst. Sci. Discuss., 12, 1653-1696, doi:10.5194/hessd-12-1653-2015, 2015
Analysis of frequency and duration of the functional periods on the basis of long-term variability of limnetic processes within the Bug River valley
Hydrol. Earth Syst. Sci. Discuss., 11, 13145-13174, doi:10.5194/hessd-11-13145-2014, 2014