Key Concepts in Hydrology and Vegetation

Item 3: Hydrology and Vegetation

Key Hydrological Terms

• River: A natural stream of water that flows into another river, a lake, or the sea.
• Full Flow: The amount of water flowing in one second past a point in the river.
• Drought: A period during which a stream reaches its lowest flow.
• Flooding: Time of maximum river flow.
• Torrente: An impetuous and violent stream, linked to heavy rains.
• Runoff: The relationship between the amount of rainfall and the amount of water that a river has.
• Fluvial Regime: The seasonal variation in the flow of a river.
• Catchment: Land whose waters pour into a main river and its tributaries.
• Slope Basin: A set of water catchments discharging to the same sea.
• Hydraulic Works: Buildings that are intended to regulate water resources (dams, channels, and transfers) or improve water quality (water treatment plants and sewage plants).
• Lake: A mass of accumulated salt or fresh water in deprived areas; it reaches a certain depth.
• Laguna: A mass of accumulated salt or fresh water in deprived areas, smaller in size and depth than lakes.
• Wetland: A land area covered by shallow water, often intermittently, due to its low level, and may even disappear during the summer drought.
• Aquifer: A sack of groundwater, which is formed when infiltrating precipitation water finds a waterproof layer and accumulates in it.
• Water Balance: The relationship between water resources and consumption.
• Dam: Hydraulic work opposing a barrier to cross a river current so that it allows the storage of water for urban and industrial supply, irrigation, electricity production, and flood prevention.
• Water Transfer: A hydraulic project aimed at transferring water from surplus river basins to deficit areas.
• Water Treatment Plant: Hydraulic work whose purpose is to treat wastewater to prevent contamination.
• Watermaker: A hydraulic project whose aim is to treat water to make it drinkable.

Vegetation and Landscape

• Vegetal Formations: Vegetation groups singled out by their physiognomy.
• Landscape Plants: The whole of plant formations that have communities in an area.
• Afforestation: A set of actions that aim to regenerate the forest in farms or areas where trees have been destroyed or cut.
• Landa: Dense shrub vegetation, typical of an oceanic climate, which can appear as deciduous forest degradation or supraforestal vegetation.
• Maquis: Dense, almost impenetrable shrub, more than two meters high (jara, heather, mastic, broom). It is typical of the Mediterranean climate.
• Garrigue: Shrubs and scrub vegetation of low height, leaving bare spots (thyme, rosemary, lavender). It is typical of the Mediterranean climate.
• Steppe: Gnarled shrub vegetation, thorny, low, and discontinuous, leaving significant areas of bare soil (hearts of palm, thyme, espartal, asparagus). It is typical of the sub-desert or steppe Mediterranean climate.
• Soil: The layer of the Earth's crust. It consists of solid (minerals and humus), liquid elements (water), and gases (CO2).
• Climax: The final stage of the formation of an ecosystem in which it reaches equilibrium with the environment, without the intervention of a human being.

Item 4: Environmental Concerns

Pollution and Environmental Issues

• Primary Pollutants: Pollutants discharged into the atmosphere.
• Secondary Pollutants: Pollutants generated by chemical and photochemical reactions (due to sunlight) of the primary pollutants.
• Acid Rain: Precipitation with a higher acidity level than normal. It causes changes in vegetation, soil, water, and buildings.
• Greenhouse Effect: An effect caused by the emission of greenhouse gases like methane and carbon dioxide. These gases let in sunlight, but once it reaches Earth, they retain it and prevent it from escaping into outer space.
• Soil Contamination: Contamination that is the result of industrial and municipal discharges and the abusive use of chemical fertilizers and pesticides in agricultural activities, which may lead to toxic soil characteristics.
• Desertification: The loss of topsoil.
• Deforestation: The destruction of trees and ground plants.
• National Parks: Parks that have a relative extension as a result of their unique characteristics in geology, hydrology, vegetation, or fauna. They are the most protected areas.