EVOLUTION OF HYDROGRAPHY 

SHORT RESUME

"EVOLUTION OF HYDROGRAPHIC NETWORKS IN THE THREE DIMENSIONS OF SPACE AND TIME"

The core idea is to define the evolutionary trends of a river network and identify the resulting risks and hazards.

Infact evolutionary processes of hidrography are due to erosional processes above all that interact with other morphological processes and with infrastructures so as roards network.

The proposed model hypothesizes that a hydrographic network's state of "precarious equilibrium" can be identified by its geometric layout, particularly its vertical profile and by spatial relationships with potential energy values of surfacial runoff waters.

These aspects or relationships are represented by two key curves taht are the Potential Energy Profile and the Frequency Distribution Curve (FDC).

The central hypothesis is that the Potential Energy Profile dictates the behavior of the hydrographic network. 

In teh proposed model they will be identified two crucial points along a basin's hypsometric\hypsographic curve and these two points define an "ACTIVE ALTIMETRIC BAND" where the river network is actively eroding and evolving.

The Critical Point (Pc​) it's the upstream point where erosive processes begin, determined by sufficient energy in the surface runoff, and the Equilibrium Point (Pe​) is the downstream point where erosive processes cease and sediment transport/deposition begin.

The method to individualize this "ACTIVE ALTIMETRIC BAND" involves comparing three important curves in a single graph and these curves are:

HYPSOMETRIC CURVE: Represents the distribution of elevations within the basin.

POTENTIAL ENERGY PROFILE: A curve representing the potential energy of runoff at different elevations. It is calculated using the formula Epi​=γ×(Ai​×pi​)×Hi​, where energy depends on specific weight (γ), cumulative area (Ai​), precipitation (pi​), and elevation (Hi​). 

FREQUENCY DISTRIBUTION CURVE (FDC): Describes the distribution of the hydrographic network (specifically third-order streams or gullies) along different elevations.

Once this particular BAND is defined we proced to verify the conditions of risk and dangers.