Catchment area

Waters

In the traditional sense it is groundwater with a piezometric level large enough to flow naturally through wells or springs. It is more advisable to talk about emerging water.[1].

Capillary water is the fraction of water that occupies the micropores in the soil. It remains in the ground thanks to the forces derived from the surface tension of water. This fraction of the water is usable by plants, it is the soil's water reserve.

It is the water that is trapped between the interstices of a sedimentary rock during its formation and that has remained isolated from the atmosphere since then.

It is natural water that contains a salt concentration < 1g/L.

A term originally applied only to water occurring in the upper part of the saturation zone under phreatic conditions, but has come to be applied to all water occurring in the unconfined saturation zone. At its upper limit it is at atmospheric pressure.[1].

It is the water in the unsaturated zone that moves under the influence of gravity. It is also called gravity-drainable water.[1].

It is the fraction of the water that occupies the macropores of the soil, saturating them or not. This fraction of water in the soil moves driven by the force of gravity, which tends to move it downward. This fraction of soil water can temporarily be used by plants while it is in the reticular stratum of the plants.

Hygroscopic or molecular water is the fraction of water absorbed directly from air humidity. This is arranged on the soil particles in a layer 15 to 20 molecules thick and adheres to the particle by surface adhesion. The suction power of the roots is not strong enough to extract this film of water from the ground. In other words, this portion of the water in the soil is not usable by plants.

It is the term applied to water that is derived directly from magma and is assumed to have originally come from the interior of the Earth.[1].

It is the water that is extracted from great depths to the surface of the land incorporated into the vertical movement of igneous rocks.[1].

It is the groundwater that has been mostly recharged after 1963/64 and is characterized by having high tritium and radiocarbon activities produced by nuclear bombs. It is also called recent water.[1].

Unretained water is defined as the sum of Surface runoff and Excess water in the soil (Water that exceeds the water content of the soil at field capacity)[2].

It is water with a salt concentration greater than 10 g/L.

It is groundwater that contains a total salt concentration of 1 to 10 g/L.

Groundwater with a piezometric level high enough to flow naturally through wells or springs.[1].

It is the water found in the unsaturated zone.[1].

Liquid flow

Flow rate: volume of water that passes through a certain cross section in the unit of time, generally expressed in m³/s.

To determine the maximum instantaneous flow rate (q) that occurred in a control section, in a given period of time, generally during the passage of a flood wave, a recording instrument must be available. They are expressed in m³/s and are associated with the date on which they were recorded.

It is an important parameter to determine the runoff capacity in hydraulic works that should not be exceeded, since this would cause significant damage.

When there are multi-year flow records, a series of maximum instantaneous flows are usually defined for each year, in this way statistical studies can be developed and these flows associated with return times.

Average flow over the period of one hour (Q). For its determination, a recording instrument must be available in the control section.

The average daily flow (Q). This can be determined in two different ways, if there is a continuous record of the flow:

If you have a traditional register, that is, a graduated rule, which is read visually by an observer, twice a day, at pre-established times, you will have to:

The maximum daily flow in a certain period, such as a month, a year, or a multi-year period, refers to the highest numerical value of the series of average daily flows, in the period considered.

The maximum daily flow, on the other hand, is the maximum recorded value of the instantaneous flow in the period of 24 hours.

The firm flow is the flow that can be found in a watercourse even at the end of the most critical dry season, over a long observation period.

If there is a reservoir upstream of the section of the watercourse being analyzed, the firm flow, in proximity to the dam, is equivalent to the flow regularized by the reservoir minus the sum of the flows derived from the reservoir for the various uses.

Also called: Safe flow: is the average flow that can be extracted in the long term from an aquifer or aquifer system, or from a surface water system, without causing undesirable results.[1].