Hydrology Terms Defined

Tributary

River that flows into another, larger river.

Stream

A small, continuous flow of water in a channel.

Flash Flood

Sudden, violent increase in water level flowing down a stream or dry channel, occurring abruptly in areas with steep slopes.

Water Balance

The relationship between available water resources and their use. In Spain, this balance is currently considered positive.

Flow (Discharge)

The amount of water flowing through a river channel at a specific point in time, typically measured in cubic meters per second.

Instantaneous Flow

The instantaneous amount of water passing a specific point in a river per second.

Hydrographic Basin (Drainage Basin)

The territory where all surface water drains to a common point, such as a river, lake, or ocean. Basins can be exorheic (draining to the sea) or endorheic (draining internally).

River Course

The path a river follows from its source to its mouth.

Dry Season

The period when river flow is lowest, often occurring in summer.

Lake

A large body of still water, either freshwater or saltwater, located in a depression on the land surface.

Source (River Source)

The natural point where a stream or river begins.

Meander

A winding curve or bend in a river channel. Meanders form due to erosion on the outer bank (where water velocity is highest) and deposition on the inner bank (where velocity is lowest), especially on flatter terrain.

Weir

A small dam built across a river or stream to raise the water level or divert flow, often creating a small reservoir for purposes like irrigation.

Rambla

A dry, flat-bottomed streambed or channel, typically found in arid or semi-arid regions, that carries water only during periods of heavy rainfall. Often found near river mouths or coastal areas.

River Regime

The seasonal pattern of flow variation in a river, influenced by factors such as rainfall distribution, snowmelt, and ice formation. Regimes can be simple (e.g., rain-fed) or complex (e.g., mixed rain and snowmelt).

River

A large, natural stream of freshwater flowing in a channel towards another river, lake, or the ocean. Rivers are typically fed by rainfall, snowmelt, and groundwater.

Torrent

A fast-flowing stream of water, especially one caused by heavy rainfall or snowmelt.

Water Transfer

The artificial movement of water from one river basin (with surplus water) to another (with water shortage), often via canals or pipelines, typically to meet demand for uses like irrigation or public supply.

Drainage Systems

A network of rivers and streams within a drainage basin that collects and channels water towards an outlet (e.g., a sea or ocean). Examples in Spain include the Cantabrian (short, fast rivers), Atlantic (long rivers), and Mediterranean (short, irregular flow, prone to drought, like Ramblas) systems.