studying risk and frequency analysis of flood is done in order to design structures located in floody lands. in hydrological and water resources engineering projects, first of all, we should determine frequency of this phenomenon- their return period. in this research, the method of planning, the cumulative freguency curve is explained and probability and return period and errors concerning sma...

Due to heterogeneity of lands over ungauged/sparsely gauged watersheds at which the hydrological flows occur, there is a need to upscale the hydrological conservation equations to the scale of the grid areas of the numerical mesh laid out over the watershed which is being modelled. A literature review of the various methods utilized in hydrology for the upscaling of hydrological conservation eq...

Distributed hydrological models combine observations and knowledge about a hydrological system to make spatial predictions of hydrological attributes. These models require methods to assess their performance at spatial prediction. The current practice for assessment is simplistic. For qualitative assessment, simulated spatial patterns are compared visually against an observed pattern to assess ...

Global gridded precipitations have been extensively considered as the input of hydrological models for runoff simulations around world. However, limitations hydrologic and inaccuracies precipitation datasets could result in large uncertainty forecasts water resource estimations. Therefore, it is great importance to investigate value a weighted combination driven by different datasets. In additi...

An operational hydrological ensemble forecasting system based on a meteorological ensemble prediction system (M-EPS) coupled with a hydrological model searches to capture the uncertainties associated with the meteorological prediction to better predict river flows. However, the structure of the hydrological model is also an important source of uncertainty that has to be taken into account. This...

Hydrological processes such as runoff and contaminant transport are usually affected by various complex interrelated variables. Moreover, uncertainties in variables estimate are the common stamp of these processes. Due to this complex nature, Physical modeling of any hydrological system requires availability of large, accurate and detailed data related to all influencing variables, which are no...

This paper combines an empirical paired-catchment method with hydrological simulation techniques in quantifying and explaining the influence of forest removal on streamflow generation. The pair of catchments (56 and 29 ha) is located in a northern boreal zone in eastern Finland. As the first part of the study, measured streamflows from the two catchments, of which one has been partially clear-c...

The baseflow is the drainage from the groundwater and soil water to the streamflow. As one important source of the streamflow, the baseflow could be the main source of the streamflow in the dry season. The Wei River, located in the semi-arid region of the Loess Plateau which is overlain by deep and loose soil, is the largest tributary of the Yellow River. According to former research, most of t...

Hydrological time series forecasting remains a difficult task due to its complicated nonlinear, non-stationary and multi-scale characteristics. To solve this difficulty and improve the prediction accuracy, a novel four-stage hybrid model is proposed for hydrological time series forecasting based on the principle of 'denoising, decomposition and ensemble'. The proposed model has four stages, i.e...

Due to biases in the output of climate models, a bias correction is often needed to make the output suitable for use in hydrological simulations. In most cases only the temperature and precipitation values are bias corrected. However, often there are also biases in other variables such as radiation, humidity and wind speed. In this study we tested to what extent it is also needed to bias correc...