Outline of hydrology

The following outline is provided as an overview of and topical guide to hydrology:

Hydrology – study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability.

Essence of hydrology

Main article: Hydrology

• Water
• Hydrologic cycle
• Cryosphere
• water on Earth

Branches of hydrology

• Hydrometry – the measurement of the different components of the hydrologic cycle
• Chemical hydrology – the study of the chemical characteristics of water
• Ecohydrology – the study of interactions between organisms and the hydrologic cycle
• Hydrogeology – the study of the presence and movement of water in aquifers
• Hydroinformatics – the adaptation of information technology to hydrology and water resources applications
• Hydrometeorology – the study of the transfer of water and energy between land and water body surfaces and the lower atmosphere
• Isotope hydrology – the study of the isotopic signatures of water
• Surface hydrology – the study of hydrologic processes that operate at or near the Earth's surface
• Catchment hydrology – study of the governing processes in a given hydrologically-defined catchment

History of hydrology

Main article: History of hydrology

Water movement pathways

Above ground

• Evaporation –

• Pan evaporation –

• Interception –

• Evapotranspiration –

• Stemflow –
• Throughfall –

On ground

• Surface runoff –
• Overland flow –
• Horton overland flow –

Below ground

• Infiltration –
• Pipeflow –
• Baseflow –
• Subsurface flow –

Further information: Hydrological phenomenon

Measurement tools

Groundwater

• Aquifer characterization

• Flow direction

• Piezometer - groundwater pressure and, by inference, groundwater depth (see: aquifer test)
• Conductivity, storativity, transmisivity
• Geophysical methods

• Vadose zone characterization
  • Infiltration
    • Infiltrometer - infiltration
  • Soil moisture
    • Capacitance probe-soil moisture
    • Time domain reflectometer - soil moisture
    • Tensiometer - soil moisture
    • Solute sampling
    • Geophysical methods

Surface water

• Water level

• Mechanical pressure gauge –
• Electronic pressure gauge –
• Acoustic pressure gauge –

• Channel shape

• Dumpy level –

• Discharge

• Acoustic Doppler velocimeter –
• Dilution tracing –

Meteorological

• Precipitation

• Rain gauge – rainfall depth (unit) and intensity (unit time⁻¹)
• Disdrometer – raindrop size, total precipitation depth and intensity
• Doppler weather radar – raindrop size, total precipitation depth and intensity, rain cloud reflectivity converted to precipitation intensity through calibration to rain gauges
• Wind profiler – precipitation vertical and horizontal motion, vertical cross-section of reflectivity and typing

• Frozen precipitation (on ground)

• Pressure sensors – pressure, depth, and liquid water equivalent
• Acoustic sensors – pressure, depth, and liquid water equivalent

• Mean windspeed and direction

• Anemometer –
• Doppler sonar –
• Wind profiler – air vertical and horizontal motion

• Mean air temperature

• Thermometer –

• Humidity

• Infrared thermometer – a form of remote sensing
• Hygrometer (Psychrometer) – measures relative humidity

• Air pressure

• Barometer –

• Heat flux

• Net radiometer –
• Pyranometer –
• Pyrgeometer –
• Heat flux sensor –
• Lysimeter –

• Cloudiness/Sunshine

• Spectroradiometer –
• Campbell–Stokes recorder –

• Evapotranspiration

• Water budget method

• Basin water balance –
• Evaporation pan –
• Lysimetry –
• Soil moisture depletion –

• Water vapor transfer method

• Bowen ratio – considers the energy budget
• Eddy covariance –

• Component analysis

• Porometry/Sap flow –
• Interception loss –
• Soil evaporation –

• Large-scale

• Scintillometer –
• Remote sensing estimates –
• LIDAR –

Soil/porous media

• Bulk density & porosity

• Oven dried sample –

• Matric potential

• Suction plate – determines relationship between the water volume and matric potential
• Resistance thermometer – relates to matric potential from previous calibration

• Hydraulic conductivity

• Disc permeameter – measures soil hydraulic conductivity
• Rainfall simulator – measures output through the application of constant input ("rain") in a sealed area
• Slug test – addition or removal of water and monitors the time until return to predisturbance level

• Piezometer –
• Soil moisture content (water volume percentage)

• Frequency domain sensor –
• Time domain reflectometer –
• Neutron probe –

Water quality

• Conductivity

• Electrical conductivity – variety of probes used

• pH

• pH meter –

• Dissolved oxygen (DO)

• Winkler test –

• Turbidity

• Nephelometer (Turbidimeter) –

• Water clarity

• Secchi disk –

• Bed load
• Erosion/deposition

Modeling

• Behavioral modeling in hydrology

Equations

Basin

• Hack's law –

Catchment

• Water balance –

Evaporation

• Penman –
• Penman-Monteith –

Infiltration/Soil Movement

• Darcy's Law –

• Darcy-Weisbach –

• Richards equation –

Streamflow/Open channel

• Fick's law of diffusion –
• Chézy formula –
• Manning formula –
• Strahler number –
• Standard Step Method – computational technique for modeling steady state open channel surface profiles

Erosion

• Hjulstrøm curve –

Groundwater

• Dupuit–Forchheimer assumption –
• Groundwater flow equation –

Power/Uncertainty

• Nash–Sutcliffe model efficiency coefficient
• GLUE

Models

Main article: Hydrological transport model

See also: Runoff model (reservoir)

• GSSHA
• HEC-HMS
• DSSAM
• HBV
• MOHID Water Modelling System

• MOHID Land

• SWAT
• SahysMod
• SaltMod
• DRAINMOD[1]
• SEDCAD

Persons influential in the field of hydrology

Hydrology scholars

Ven Te Chow, Professor of Hydraulic Engineering, University of Illinois. Most noted for the 1964 compendium of water resources technology and methods titled "Handbook of Applied Hydrology", published by McGraw-Hill Book Company. Library of Congress Catalogue number 63-13931.

Environmental issues

• Desertification/Oasification –
• Hypoxia –
• Erosion –
• Water pollution –

Allied sciences

• Aquatic chemistry –
• Civil engineering –

• Hydraulic engineering –

• Climatology –
• Environmental engineering –
• Environmental Engineering Science –
• Geomorphology –
• Hydroacoustics –
• Hydrography –

• Limnology –
• Oceanography –

• Physical geography –

Hydrology lists

• Drainage basins by area – largest hydrologically defined watersheds in the world
• Floods – chronological and geographic list of major floods worldwide
• Waterways – worldwide listing of waterbodies classified as rivers, canals, estuarys, and firths