The expression ecological flow, referring to a river or any other current water channel, is an expression that can be defined as the water necessary to preserve the ecological values in its channel, such as:
Any project that involves the diversion of water from natural water channels (drinking water, irrigation, hydroelectric plants, etc.) must consider the conservation of the ecological flow downstream of the works, to avoid the alteration of the ecological corridors constituted by these water channels.
Definitions and Concepts
The expression ecological flow, referring to a stretch of running water channel, contains a concept that can be defined as the minimum flow of water necessary to preserve the ecological values of the channel, such as:.
The determination of the ecological flow of a river or stream is made according to a careful analysis of the minimum needs of the existing ecosystems in the area of influence of the hydraulic structure that in some way will modify the natural flow of the river or stream.
Another valid definition of the same concept would be the following: Ecological flow is the minimum flow that must be maintained in a watercourse when building a dam, a catchment, or a diversion, so that the natural conditions of the biotope are not altered and the development of a natural life equal to that which previously existed is guaranteed.
Determination of ecological flow
Many methods and methodologies have been developed to determine the flow requirements of ecosystems.
The simplest are the hydrological or statistical methods, which determine the minimum ecological flow through the study of flow data. An example of a simple statistical method is to define the minimum ecological flow as 10% of the historical average flow, which is precisely what is foreseen, at least to date, in the Hydrological Plan of the Ebro River Basin.
The ecological flow is therefore considered as a general restriction that is imposed on all exploitation systems without prejudice to the principle of supremacy of use for the supply of populations.
Ecological flow
Introduction
The expression ecological flow, referring to a river or any other current water channel, is an expression that can be defined as the water necessary to preserve the ecological values in its channel, such as:
Any project that involves the diversion of water from natural water channels (drinking water, irrigation, hydroelectric plants, etc.) must consider the conservation of the ecological flow downstream of the works, to avoid the alteration of the ecological corridors constituted by these water channels.
Definitions and Concepts
The expression ecological flow, referring to a stretch of running water channel, contains a concept that can be defined as the minimum flow of water necessary to preserve the ecological values of the channel, such as:.
The determination of the ecological flow of a river or stream is made according to a careful analysis of the minimum needs of the existing ecosystems in the area of influence of the hydraulic structure that in some way will modify the natural flow of the river or stream.
Another valid definition of the same concept would be the following: Ecological flow is the minimum flow that must be maintained in a watercourse when building a dam, a catchment, or a diversion, so that the natural conditions of the biotope are not altered and the development of a natural life equal to that which previously existed is guaranteed.
Determination of ecological flow
Many methods and methodologies have been developed to determine the flow requirements of ecosystems.
The simplest are the hydrological or statistical methods, which determine the minimum ecological flow through the study of flow data. An example of a simple statistical method is to define the minimum ecological flow as 10% of the historical average flow, which is precisely what is foreseen, at least to date, in the Hydrological Plan of the Ebro River Basin.
The ecological flow is generally set in the "Basin Management Plans",[1] based on specific studies or specific analyzes for each section of the river, stream or channel downstream of the source. The characterization of environmental demand (that is, the amount of water that is considered ecological flow) is also agreed upon with the intervention of the different sectors involved, from planning to water use.
The components of the ecological flow regime are:
Minimum flow: it is the lowest flow necessary for the structure of the river and the habitats that support life to be preserved and able to develop their functions. It must be overcome since, below it, many organisms would die.
Maximum flow: it is the flow that must not be exceeded in the river due to the ordinary release of flows from a dam. Its function is to not harm the most vulnerable native species, since a flow that exceeds the critical speed drags downstream and reduces populations due to depletion.
Both the minimum and maximum flow must be differentiated by month for a better approximation to the natural state, where the river fluctuated continuously depending on rainfall and geomorphological characteristics, with its species adapted to these movements.
Generating, flood or flood flow: it is what originates the morphology of the channel and is established by imitating the ordinary floods of the river, allowing the fertilization of the flood plain, it has the function of maintaining the river substrate and the riverside vegetation in good condition. It is essential to maintain natural dynamics and good ecological status.
Rate of change: refers to the changes in the volume of flow released by a dam per unit of time to avoid the negative effects of a sudden variation in flow. These effects can be the dragging of aquatic fauna during the rising phase, or their isolation in the falling phase of the flows. They must also take into account the maintenance of favorable conditions for the regeneration of aquatic and riverine plant species.
The requirements
The ecological flow must meet the following requirements:
The ecological flow is therefore considered as a general restriction that is imposed on all exploitation systems without prejudice to the principle of supremacy of use for the supply of populations.
The ecological flow is generally set in the "Basin Management Plans",[1] based on specific studies or specific analyzes for each section of the river, stream or channel downstream of the source. The characterization of environmental demand (that is, the amount of water that is considered ecological flow) is also agreed upon with the intervention of the different sectors involved, from planning to water use.
The components of the ecological flow regime are:
Minimum flow: it is the lowest flow necessary for the structure of the river and the habitats that support life to be preserved and able to develop their functions. It must be overcome since, below it, many organisms would die.
Maximum flow: it is the flow that must not be exceeded in the river due to the ordinary release of flows from a dam. Its function is to not harm the most vulnerable native species, since a flow that exceeds the critical speed drags downstream and reduces populations due to depletion.
Both the minimum and maximum flow must be differentiated by month for a better approximation to the natural state, where the river fluctuated continuously depending on rainfall and geomorphological characteristics, with its species adapted to these movements.
Generating, flood or flood flow: it is what originates the morphology of the channel and is established by imitating the ordinary floods of the river, allowing the fertilization of the flood plain, it has the function of maintaining the river substrate and the riverside vegetation in good condition. It is essential to maintain natural dynamics and good ecological status.
Rate of change: refers to the changes in the volume of flow released by a dam per unit of time to avoid the negative effects of a sudden variation in flow. These effects can be the dragging of aquatic fauna during the rising phase, or their isolation in the falling phase of the flows. They must also take into account the maintenance of favorable conditions for the regeneration of aquatic and riverine plant species.
The requirements
The ecological flow must meet the following requirements: