Hydrology is the study of the distribution and movement of water on and below the Earth's surface, as well as the impact of human activity on water availability. Various hydrological models have been developed worldwide to understand the impact of climate and soil on water resources, with the best models providing results close to reality using few parameters. Rainfall-runoff models are classified as lumped or distributed based on how model parameters vary over space and time, and as deterministic or stochastic based on other criteria. Examples of hydrological models discussed include SWAT, MIKE SHE, HBV, TOPMODEL, and VIC.

2. Hydrology
Hydrology is the study of the distribution and movement of
water both on and below the Earth’s surface, as well as the
impact of human activity on water availability and conditions.

3. Hydrological
models
Various hydrological models have been developed across the
world to find out the impact of climate and soil properties on
hydrology and water resources .
A model is simplified representation of real-world system. The
best model is the one which give result close to reality with the
use of least parameters and model complexity.

4. Hydrological
models
A model consists of various parameters that define
characteristics of the models.
The two important inpust are rainfall data and drainage area.
Along with these watershed caracteristics.
• Soil properties
• Vegetation cover
• Watershed topography

5. Types of
models
Rainfall-runoff models are classified based on model input and parameters
and the extent of physical principles applied in the model. It can be
classified as lumped and distributed model based on the model parameters
as a
function of space and time and deterministic and stochastic models based
on the other criteria.
1. Empirical models (Metric model)
2. Conceptual methods (Parametric models)
3. Physically based model

6. Brief description of few models
Development of SWAT model is an ongoing process and it is the successor
of “the Simulator for Water Resources in Rural Basins” model.
SWAT model is a complex physically based model and was designed to test
and forecast the water and sediment circulation and agriculture
production with chemicals in ungauged basins.
The model breaks the entire catchment in to sub catchments which are
further divided in to hydrologic response units (HRU), land use,
vegetation and soil
characteristics. Based on amount of precipitation and mean daily air
temperature rate of snowfall
can be determined.
1. MIKE SHE model (Systeme Hydrologique European)
2. HBV model (Hydrologiska Byrans Vattenavdelning model)
3. Top model
4. VIC model (Variable Infiltration Capacity model).

7. Thanks for you attention