What is hydrology?
is the science that encompasses the occurrence,
distribution, movement and properties of the waters of the
Earth and their relationship with the environment.
What do hydrologists do?
Hydrologists study fundamental transport processes to
describe the quantity and quality of water as it moves
through the hydrological cycle:
– evaporation, precipitation, streamflow, infiltration, groundwater flow,
and other related processes.
different sub-branches of hydrology and how they are interlinked
-Hydrometeorology: weather patterns, rainfall & climate.
• Surface hydrology: surficial water flow processes, floods, low flows.
• Groundwater hydrology (hydrogeology): subsurface water flow
patterns and storage.
• Ecohydrology: hydrological cycle ecosystem interactions.
• Urban hydrology: water flow and quality in urban environments.
• Water quality: water chemistry in rivers/lakes, pollutants and
• Hydrological models: simplified, conceptual realisations of
hydrological cycle data based or process description based.
• Stochastic hydrology: applying probabilistic methods to model
hydrological processes with random components (e.g. rainfall).
Agriculture and irrigation
– Provision of drinking water supply
– Reservoir storage, groundwater
-Design of flood prevention schemes
– Sustainable urban drainage systems
Managing water resources
what a watershed or catchment is and how it is defined
A catchment or watershed is the total area which drains into a common outlet
spatial and temporal scales of interest in hydrology processes
Spatial scales vary from a few meters to hundreds of
– Surface water and groundwater are related at large scales
– Local processes are affected by regional changes.
key hydrologic processes for water movement through cycle
Movement of water through hydrological cycle: – Evaporation – Condensation – Precipitation – Transpiration – Infiltration – Abstraction – Runoff
key factors affecting water cycle
– Land use
the need for gauging stations around Scotland and UK
- Runoff prediction
– Stream flow prediction
Amount of water vapour held in
air is absolute humidity (g/kg air)
water absorption by plants (usually through roots)
What is runoff?
Portion of precipitation (rain or snow) that
does not percolate into ground and
discharges into streams instead.