Hydrology

2 Hydrologic Study

Scientific Hydrology

Engineering or Applied Hydrology

Water in various state with different hydrological state or process

Hydrologic Cycle

Types of Hydrologic Cycle

Precipitation

Evaporation

Infiltration (Percolation)

Transpiration

Run-off

Stream Flow

Condensed water in atmosphere

Precipitation

Liquid water to gas

Evaporation

entering of water to ground

Infiltration

Water from grounds to plants

Transpiration

Paths above the surface of the earth reaching the stream channel

Run-off

Run-off that reaches channel

Stream Flow

Types of Temporary Storage (Depression Storage)

Reservoir

Dams

Ponds

Hydrologic Alterations or Modifications

Artificial Rain (Cloud Seeding)

Evaporation Suppression

Change of Vegetal Cover & Land Use

Watershed

Types of Watershed

Catchment Area

Divide

Area of land draining intro stream or water course

Catchment

Other term for Catchment Area

Drainage Area or Drainage Basin

Ridge separating the catchment area from its neighboring areas

Divide

Forms of Precipitation

Rain

Snow

Drizzle

Glaze

Sleet

Hail

Water drops of sizes larger than 0.5mm

Rain

Ice crystals which usually combine to form flakes

Snow

Fine sprinkle of water droplets

Drizzle

Freezing rain form on ground

Glaze

Frozen raindrops of transparent grains (rain freezes BEFORE impact on ground)

Sleet

Showering precipitation - irregular pallets or lumps of ice

Hail

Interface between 2 distinct air masses

Front

2 Types of Fronts

Warm front

Cold front

Large low pressure region with circular wind motion (counter clockwise)

Cyclone

2 Types of Cyclone

Tropical Cyclone

Extreme Tropical Cyclone

clockwise wind circulation in north hemisphere

Anti-Cyclone

pocket of air which it warmer that the surrounding air

Convective Precipitation

Due to the lifted moist air masses brought by intervening mountain barriers

Orographic Precipitation

Consists of cylindrical vessel assembly kept in the open to collect rain

Rain Gauge

2 Types of Rain Gauge

Non-Recording Gauges

Recording Gauges

3 Types of Recording Gauges

Tipping Bucket Type

Weighing Type

Natural Syphon Type

Water contained in the receiving vessel with an accuracy of 0.1m

Non-Recording Gauge

Continuous plot of rainfall against time and provide valuable data of intensity and duration of rainfall for hydrological analysis of storms

Recording Gauges

Graphical representation of the variation of rainfall depth or intensity with time.

Hyetograph

Types of Presentation of Data

Mass Curve of Rainfall

Hyetograph

Point Rainfall

Indicates cumulative rainfall depth at any time during the storm

Mass Curve of Rainfall

Refers to the rainfall data of a station. Data can be listed daily, weekly, monthly, seasonal or annual values for various periods. Data represented as plots of magnitude vs chronological time in form of a bar diagram

Point Rainfall (Station Rainfall)