Flow Capacity

Low uncertainty flow gauging service, for flow measurements in rivers, streams or canals. Generation of discharge curves in gauging sections and other studies and services.

What is Capta Hydro’s gauging service

The gauging services provided by Capta Hydro are
adapted to the measurement needs of our customers according to their objectives.
Depending on the needs, the appropriate measurement and analysis strategy is chosen to minimize the uncertainty of the measurements.
Each of the steps involved in this type of consultancy are detailed below.



The main applications of gauging services are as follows:

Point flow measurement

Point measurements are ideal for verifying ecological flows and throughflows in channels at a given time.

Loss studies

Loss studies make it possible to estimate how much water is lost in different stretches of natural watercourse or channel. For this type of study, the hydraulic times between the different points must be determined, in order to determine more accurately how much is the loss between two points.
These studies may consider the lease of equipment for the study period.

Empirical generation of discharge curves

The gauging works generally have theoretical curves, which must be verified with several empirical flow measurements, so that reliable curves are obtained over the entire flow range. This applies to all types of flumes (parshall, montana, cut throat, etc.), artificial weirs (thick or thin walled) and weirs in natural watercourses.

Proportionality study of splitting frames

The partitioning frames are fixed structures for the proportional partitioning of the flow of a channel, but whose theoretical proportion may deviate due to construction or operational effects. By performing flow measurements on two branches of the incoming and outgoing flow, the actual ratio for one or more flow endowment levels can be determined, thus determining if modifications to the civil works are required for proper flow sharing.


Depending on the particular situation,

At Capta Hydro we offer the use of two methodologies for the realization of the gaugings

Methodology / Salt Tracer


Very versatile, ideal for non-uniform, turbulent and high slope sections. Low uncertainty (less than 5%).


Measurements between 10-10,000 L/s.

Ideal application

Channels with flow rates of less than 10m3/s, turbulent rivers and estuaries, and high slope channels that consider a place where salt can be properly mixed.

Methodology / Area-Speed


Ideal for uniform and calm sections. Low uncertainty following ISO748 guidelines.
ADCP equipment provides more versatility (poorly defined geometries and places without bridges), especially in very wide channels.


Not feasible or of high uncertainty in turbulent locations or with recirculating velocities.

Ideal application

All types of channels with uniform velocities and bridges that allow the introduction of the instrument over its entire width.

Gauging campaigns on the Canal del Maipo Company's network

The Sociedad del Canal del Maipo - one of the main and oldest canal associations in the country - has an extensive network of canals that crosses all of Santiago, from its catchment on the Maipo River in Puente Alto, through almost all of the capital's municipalities to Colina and Pudahuel.

Gauging campaigns on the Canal del Maipo Company's network

In 2019 we were commissioned to conduct a gauging campaign in sections where they did not have gauging curves and in others where they required updating.

The measurements were carried out with the saline gauging methodology, which allowed the measurement of flow rates in places with difficult access, without a gauging bridge or with high turbulence due to hydraulic singularities or high slope.

Gauging campaigns on the Canal del Maipo Company's network

At each point, in addition to obtaining the gauging curves, an evaluation and recommendations for improvements to the gauging sections of the canals were made, in addition to correctly defining the height measurement reference from the height of the barrier for the construction of the discharge curve for dozens of points in the network.


The gauging campaigns carried out by Capta Hydro on our water distribution canal networks have allowed us to maintain the necessary accuracy to ensure the correct distribution of water among our canals.

Juan Carlos Berrios

Operations Manager, Sociedad del Canal del Maipo