Vertisols are cracking clayey, arable soils that often overlay groundwater reservoirs. The soil cracks enable flow that bypasses soil blocks, which results in both relatively fresh recharge of the underlying groundwater and contamination with reactive contaminants. These special phenomena, as well as unique mechanism of salinization after cultivation and relative resilience to contamination by nitrate typical to groundwater under vertisols, are reviewed in this study.

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.

Low permeability sediments and rock can leak slowly, yet can act as important barriers to flow for resource development and for waste sequestration. Relatively rapid and reliable hydraulic tests of "tight" geological materials are possible by accelerating gravity. Results from geotechnical centrifuge testing of drill core and in situ pore pressure monitoring were compared with a regional flow model, and considered in the context of inherent geological variability at site and formation scale.

Existing solutions for the problem of pumping at a radial collector well (RCW) in unconfined aquifers either require laborious calculation or predict divergent results at a middle period of pumping. This study relaxes the above two limitations to develop a new analytical solution for the problem. The application of the solution is convenient for those who are not familiar with numerical methods. New findings regarding the responses of flow to pumping at RCW are addressed.

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.

Lake droughts result in significant hydrological, ecological and economic consequences. This study proposes approaches for quantifying the lake drought features and estimating the contributions from individual factors, taking China’s largest freshwater lake as a case examination. Our results showed that the recently increased lake droughts were due to hydroclimatic effects, with less important contributions from the water impoundments of the world’s largest dam affecting the lake outflows.

Removal efficiency of carbon and nitrogen in constructed wetlands is inconsistent and does not reveal whether the removal processes are from physical attenuation or transformation to other reactive forms. Previous research did not consider "pollution swapping" driven by transformational processes. Herein the biogeochemical dynamics and fate of carbon and nitrogen and their potential impact on the environment, as well as novel ways in which these knowledge gaps may be eliminated, are explored.

Three different types of gridded precipitation products are compared in a high glaciated tropical mountain environment (Cordillera Blanca, Peru): ground-based interpolation, a satellite-derived product (TRMM3B42), and outputs from the WRF regional climate model. While none of the products meets the challenge of representing both accumulated quantities and frequency of occurrence at the short timescale, we concluded that new methods should be used to merge those various precipitation products.

– A strategy to diagnose hydrological limitations of a Land Surface Model – Land Surface Model adaptation for hydrological applications – Highlights challenges faced while moving towards high resolution modelling

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 (resp. 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 into the complexity of flood risk evolution, at a local scale.

This paper was written to find the climatological characteristics of raindrop size distribution (DSD) with respect to the wind direction in Busan, Korea. The data were collected by POSS disdrometer during 4 years (2001–2004). Busan shows the tendency of land-sea breeze. When sea wind blows during rainfall period, mean size and number concentration of raindrop are smaller and larger than that of land wind blows, respectively. It means that the features of DSD depend on the wind direction.

In this study, the hydrological model J2000g was extended and applied to four selected endorheic lake basins in the southern-central part of the TP aiming to provide a more quantitative understanding of the key factors controlling their water balance. The model results indicated that the relative contribution of glacier runoff to total water inflow (between 14 and 30 %) plays a less important role compared to runoff generation from rainfall and snowmelt in non-glacierized land areas.

This paper illustrates the experimental and monitoring set-up of the 66 ha Hydrological Open Air Laboratory (HOAL) in Petzenkirchen, Lower Austria, which allows meaningful hypothesis testing. The HOAL catchment features a range of different runoff generation processes (surface runoff, springs, tile drains, wetlands), and is convenient from a logistic point of view as all instruments can be connected to the power grid and a high-speed glassfibre local area network.

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.

Catchment mean transit times have been widely inferred from seasonal cycles of environmental tracers in precipitation and streamflow. Here I show that these cycles yield strongly biased estimates of mean transit times in spatially heterogeneous catchments (and, by implication, in real-world catchments). However, I also show that these cycles can be used to reliably estimate the fraction of "young" water in streamflow, meaning water that fell as precipitation less than roughly 2–3 months ago.

Here I show that seasonal tracer cycles yield strongly biased estimates of mean transit times in nonstationary catchments (and, by implication, in real-world catchments). However, they can be used to reliably estimate the fraction of "young" water in streamflow, meaning water that fell as precipitation less than roughly 2–3 months ago. This young water fraction varies systematically between high and low flows and may help in characterizing controls on stream chemistry.

Soil moisture estimates from a novel method were evaluated in two semiarid watersheds. We found good agreements between the technique and estimates derived from watershed instruments designed to close the water balance. We then investigated local hydrologic processes and link between evapotranspiration and soil moisture obtained from the novel measurements.

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.

Caves offer a natural inception point to observe both the long-term groundwater recharge and the preferential movement of water through the unsaturated zone of such limestone. In this study, we develop a method that combines automated drip rate logging systems and remote sensing techniques to quantify the infiltration processes within a cave.

Parameter optimization is necessary to improve the flood forecasting capability of physically based distributed hydrological model. A method for parameter optimization with particle swam optimization (PSO) algorithm has been proposed for physically based distributed hydrological model in catchment flood forecasting and validated in southern China. It has found that the appropriate particle number and maximum evolution number of PSO algorithm are 20 and 30 respectively.

We define the equivalent precipitation to include local precipitation, inflow water and soil water storage change as the water supply in the Budyko framework. With the newly defined water supply, the Budyko curve can successfully describe the relationship between the evapotranspiration ratio and the aridity index at both annual and monthly timescales in unclosed basins. We develop a new Fu-type Budyko equation with two non-dimensional parameters (ω and λ) based on the deviation of Fu's equation.

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 a.s.l. elevation band contributes the bulk of snowmelt, but the 4000–5000 m a.s.l. band is a significant source and deserves further monitoring and research.

An index of floodplain surface complexity is developed in this paper and applied to eight floodplains from different geographic settings. Floodplain width and sediment yield were associated with the index or with sub-indicators, whereas hydrology was not. These findings suggest that valley and sediment conditions are important determinants of floodplain surface complexity, and these should complement hydrology as a focus of floodplain research and management.

This paper reviews literature surrounding many aspects of socio-hydrological modelling; this includes a background to the subject of socio-hydrology, reasons why socio-hydrological modelling would be used, what is to be modelled in socio-hydrology and concepts that underpin this, as well as several modelling techniques and how they may be applied in socio-hydrology.

We derived mathematical formulations of relations between relative wetness and gradients driving run-off and evaporation for a one-box model such that, when conductances are optimized with the maximum power principle, the model leads exactly to a point on the Budyko curve. With dry spells and dynamics in actual evaporation added, the model compared well with catchment observations without calibrating any parameter. The maximum-power principle may thus be used to derive the Budyko curve.

The sensitivity of the combined model (LINGRA-N and HYDRUS-1D) to hydraulic parameters, water stress, crop yield and lower boundary conditions was assessed. We showed that it is sufficient to estimate limited amount of key parameters in optimization strategies. A combined modelling approach could increase water use efficiency (12–22.5 %) and yield (5–7%) by changing irrigation scheduling. Result calls for taking into account weather forecast and soil water content data in precision agriculture.

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.

We developed 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 also developed to improve the simulation efficiency. The proposed model was applied in the Shaying River catchment, which is a highly regulated and heavily polluted region in China.

Groundwater recharge and hydraulic conductivity are both important properties of a groundwater system. However, models using 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.

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.