Understanding Water Flow, Vegetation, and Soil Dynamics
Runoff
Runoff is the water sheet flowing over the surface (the height in millimeters of rainwater runoff and extended). It forms when rainfall exceeds the infiltration capacity of the soil. It is a major cause of erosion worldwide.
River Flow
- Full flow: The amount of water passing a given point per second by a river. Measured in hm3.
- Average flow: Average flow of a series of at least 30 years.
- Fluvial regime: The seasonal variation of river flow.
- Relative flow: The amount of water the course of a river that is obtained by comparing the average annual flow (in liters/second) with the surface of the river basin. It is expressed in l/seg/km2. Used to compare rivers.
Aquifer
An aquifer is a sack of groundwater, which is formed when infiltrated rainwater finds a waterproof layer (usually clay) and accrues on it.
Vegetation Types
- Landa is a dense thicket, characteristic of an oceanic climate, which may appear as deciduous forest degradation or supraforestal vegetation (heather, gorse, broom).
- Macchia is a dense shrub, almost impenetrable, more than two meters high (jara, heather, mastic, broom). It is typical of the Mediterranean climate.
Hydrological Concepts
- Flooding: Time of maximum flow of a stream. Usually refers to abnormal and catastrophic increases.
- River basin: Area/territory bounded by mountain ranges, whose waters pour into a main river and its tributaries.
- Endorheic: A phenomenon whereby the water network does not reach the sea, but the water collects in lakes inland until it evaporates or seeps.
- Exorheic: Phenomenon by which the river system empties into the sea.
- Hydrographic areas: Assembly consisting of all watersheds that drain into the same place, whether sea or ocean. Example: Mediterranean Rim.
- Drought: A period during which the rivers or other water sources reach their lowest flow. Usually coincides with the summer months, presented as dry in most of the peninsular observatories. Is particularly marked in the southern Mediterranean rivers.
River Regimes
- Fluvial rain: Rivers that receive their maximum contribution of rainwater.
- Nival flow regime: Rivers with steep and rapid courses given their maximum amounts of water during the thaw season, spring and summer, regardless of rainfall.
- Pluvionival flow regime: Rivers that receive input from precipitation water first and then to a lesser extent, the spring thaw, usually located at altitudes between 1600 and 1800 meters, where the snows are perpetual. Example: Júcar River.
Other Hydrological Phenomena
- Floods: Providing fast and more or less violent and catastrophic water in those areas where it tends to accumulate in excess with no time for disposal or filtration.
- Salinization of aquifers: The process of accumulation of salt by seawater intrusion into a geologic formation that stores and allows groundwater to flow due to the porosity of the rock that allows water seepage and hydrostatic pressure present.
- Torrente: Intermittent water current, it just takes a lot of water for part of the year due to the rainfall. It is considered to have a torrential regime because most of the year it has no flow.
Vegetation Zones
- Floor vegetation: Each of the vegetation formations that are spread over a mountain.
- High mountain meadows: Land covered with herbaceous vegetation with natural (climax vegetation) located above the forest stratum, which is usually used by cattle.
- Eurosiberian vegetation: Ground cover that corresponds with the area of the southern slope of the Pyrenees, Pyrenean foothills, and north and northwest of the peninsula. It is characterized by the presence of dense forests that may be higher than 30 meters and tend to form monospecific formations and various shrubs, meadows, and heath. Characteristic trees: beech, oak, and chestnut.
- Macaronesian Vegetation: Tapestry own plant in the Canary Islands, which by their insularity, lithological diversity, and age of the flora has a great independence from the vegetation of the Iberian Peninsula. It is characterized by the presence of the laurel forest, very dense, and the myrtle, heather, which is the result of degradation by human action laurel.
- Endemic: A species that has a very small range because its origin is very recent and has not had time to expand.
- Mediterranean vegetation: Ground cover that corresponds to the entire Iberian Peninsula and Balearic Islands, except the Siberian region. It is characterized by the presence of evergreen forests (oak, pine, and oak) and the maquis, garrigue, and steppe.
- Sclerophyllous vegetation: Is characterized by hard, leathery leaves, leather-like consistency, due to which they are constituted by tissue formed by cells with a very thick membrane through which they adapt well to drought.
Soil Properties
- Permeability: The capacity of soils to allow infiltration of water and gases.
- Leaching: The process of trawling soluble materials by rainwater. Its intensity depends on the volume of rainfall.