Two different in situ spectrophotometers, which were used in the field to determine highly time resolved nitrate-nitrogen (NO3-N) concentrations at two distinct spring discharge sites, are compared: a double and a multiple wavelength spectrophotometer. The objective of the study was to review the hardware options, determine ease of calibration, accuracy, influence of additional substances and to assess positive and negative aspects of the two sensors as well as troubleshooting and trade-offs.

Groundwater surface mapping is used as an independent data set to better estimate groundwater discharge to streamflow. The groundwater surfaces indicated when other techniques likely overestimated the groundwater discharge component of baseflow. Groundwater surfaces also identified areas where regional groundwater could not be contributing to tributary streamflow. This method adds significant value to water resource management where sufficient groundwater monitoring data are available.

We present a proof-of-concept approximation of within-GCM uncertainty using non-stationary stochastic replicates of monthly precipitation and temperature projections and investigate the impact of within-GCM uncertainty on projected runoff and reservoir yield. Amplification of within-GCM variability from precipitation to runoff to reservoir yield suggests climate change impact assessments ignoring within-GCM uncertainty would provide water resources managers with an unjustified sense of certainty

Nutrient pollution models need to have an appropriate level of complexity and must be applicable at the mesoscale. Here we show the minimum information requirement approach to building models that are used by policy makers to look at the broad-scale effects of their decisions. CRAFT (Catchment Runoff Attenuation Flux Tool) relies on the representation of hydrological flow pathways and how they can be altered. A case study is shown to demonstrate what can be simulated at the mesoscale.

We assimilate satellite soil moisture into a rainfall-runoff model for improving flood prediction within a data-scarce region. We argue that the spatially distributed satellite data can alleviate the model prediction limitations. We show that satellite soil moisture DA reduces the uncertainty of the streamflow ensembles. We propose new techniques for the DA scheme, including seasonal error characterisation, bias correction of the satellite retrievals, and model error representation.

This study presents a modeling framework for estimating potential climate and land use change impacts for the 21st century in the Mancha Oriental aquifer. A watershed agriculturally based hydrological model (SWAT) was sequentially coupled with a groundwater flow model in MODFLOW and a groundwater mass-transport model in MT3DMS for groundwater concentrations. Future projections preview a decrease in groundwater recharge, affecting groundwater quantity, quality and interaction with the Jucar River

The study evaluates annual precipitation (largely rainfall) amounts for the tropics and subtropics; precipitation was obtained from ground observations, satellite observations and numerical weather forecasting models. - Annual precipitation amounts from ground and satellite observations were the most realistic. - Newer weather forecasting models better predicted annual precipitation than older models. - Weather forecasting models predicted inaccurate precipitation amounts for Africa.

We present an empirical study of the rates of increase in precipitation intensity with air temperature using high-resolution 10 min precipitation records in Switzerland. We estimated the scaling rates for lightning (convective) and non-lightning event subsets and show that scaling rates are between 7 and 14%/C for convective rain and that mixing of storm types exaggerates the relations to air temperature. Doubled CC rates reported by other studies are an exception in our data set.

River flows depend not only on how much water is in a catchment, but also on where the water is stored, which changes over time. We monitored streamflow, soil moisture, and groundwater levels in a NZ catchment, to find out what controls water storage and variability. We found that the catchment had a summer mode where water storage is controlled by near-surface interactions of water with soils and vegetation, and a winter mode where water storage is controlled by deeper groundwater movement.

High-resolution three-dimensional point clouds are used to analyse erosion processes at the millimetre scale. The processes analysed here play a role in the closure of cracks. We demonstrated how micro-scale infiltration can influence the degradation of soil surface by inducing downward mass movements that are not reversible. This development will aid in designing future experiments to analyse processes such as swelling, crack closure, micro-landslides, etc.

Using two sites with different climates, we show that a 1-pixel version of a distributed hydrologic model that uses a single soil layer with a novel dual-pore structure and employs linear parameterization for infiltration and other fluxes and has comparable performance to a benchmark detailed soil water physics solver in capturing the essential local-scale soil moisture dynamics.

The paper asks why the Arkavathy River in southern India is drying. The study results indicate that anthropogenic drivers like groundwater pumping, eucalyptus plantations and channel fragmentation are much more likely to have caused the decline than changing climate. The multiple-hypothesis approach presents a systematic way of quantifying the relative contributions of different drivers, contributing to the policy debate and prioritizing new scientific research.

We use a virtual mission analysis on a ca. 260km reach of the central Amazon River to assess the hydraulic implications of potential measurement errors in swath-altimetry imagery from the forthcoming Surface Water and Ocean Topography (SWOT) satellite mission. We estimated water surface slope from imagery of water heights and then derived channel discharge. Errors in estimated discharge were lowest when using longer reach lengths and channel cross-sectional averaging to estimate water slopes.

We present a novel simulation method for estimating spatially distributed and transient groundwater recharge in unconfined sandy aquifers. The approach uses field data for the most important parameters affecting groundwater recharge and accounts for parameter uncertainty. The results show that tree canopy cover is the most important factor in controlling groundwater recharge at our study area. Tree canopy is thinned by forestry, which may lead to a significant increase of groundwater recharge.

1. Catchments with higher snow ratio tend to have larger runoff index. 2. A modified Budyko method is proposed to illustrate the snow effect on runoff. 3. Snow ratio change has a significant contribution to runoff change, according to historical observations and projected future climate scenarios, especially in northwestern mountainous and northern high-latitude areas of China.

Hydrological drought types in cold climates have complex causing factors and impacts. In Austria and Norway, a lack of snowmelt is mainly related to below-normal winter precipitation, and a lack of glaciermelt is mainly related to below-normal summer temperature. These and other hydrological drought types impacted hydropower production, water supply, and agriculture in Europe and the US in the recent and far past. For selected drought events in Norway impacts could be coupled to causing factors.

The study compared evapotranspiration (ET) modelled by two remote sensing models and one hydrological model in a river catchment in Denmark. The results show that the spatial patterns of ET produced by the remote sensing models are more similar to each other than to the fluxes produced by the hydrological model. This indicates potential benefits to the hydrological modelling community from integrating spatial information derived through remote sensing methodology into the hydrological models.

We reconstructed a 100-year monthly history of flooding and drought of a large wetland in arid northwest Australia, using hydroclimatic data calibrated against 25 years of satellite images. Severe and intense regional rainfall, as well as the sequence of events, determined surface water expression on the floodplain. While inter-annual variability was high, changes to the flood regime over the last 20 years suggest the wetland may become more persistent in response to the observed rainfall trend.

We present the outcomes of a collaborative hydrological experiment undertaken by five different international research groups in a virtual laboratory. Moving from the definition of accurate protocols, a rainfall-runoff model was independently applied by the research groups, which then engaged in a comparative discussion. The results revealed that sharing protocols and running the experiment within a controlled environment is fundamental for ensuring experiment repeatability and reproducibility.