Improving hydrological services for a 3100 MW hydropower dam on the mighty Parana River

1000 Cubic Metres per second thundering through the spillway. An incredible sight. That is the minimum flow that is released through the auxiliary spillway of the Yacyretá Dam, and constitutes the environmental flow release through the auxiliary spillway. This is a dam of superlatives. Built on the Parana River, the 808-metre main dam straddles the Argentinean-Paraguayan border and incorporates the powerhouse with 18 turbines, as well as the main spillway. The total length of the main and auxiliary dams is, however, over 35 km. The installed capacity of 3100 MW makes this is one of the ten largest hydropower facilities in South America. Yacyretá dam is some 400 km downstream of the famous Itaipú dam, the second largest hydropower station by installed capacity in the world. The reservoir formed by the dam is so wide that it is impossible to see the opposite bank. 

Incredibly though, despite its size, it is generally considered a run-of-the-river hydropower plant. The average flow of 14,500 m3/s, means that the volume stored in the reservoir is in fact relatively small. This means that a good forecast of the inflow discharge into the reservoir, coming primarily from the Parana River, is of key importance to the planning of hydropower scheduling, and the small team of hydrologists working for the Entidad Binacional Yacyeretá (EBY); the joint Argentinian-Paraguayan operator of the dam, therefore have a pivotal role in its operation. They provide daily bulletins of current and forecast hydrological conditions to a range of different sectors; including power generation and scheduling, navigation, environment, flood control, and irrigation. Additionally, several other users are also provided tailored information; including the maintenance, civil works, and environment departments.

Over the years the team of hydrologists have developed a range of monitoring and modelling tools, including hydrological (HEC-HMS) and hydraulic models (HEC-RAS and Kanali), and a suite of spreadsheet-based regression tools. Having grown organically, these do provide the required information, but also demand quite some effort to use. To improve the efficiency of day-to-day operations, the hydrologists at EBY have chosen to introduce Delft FEWS to be the backbone of their operational system. This it is envisaged will help enhance and improve the service they provide. Integrating the current tools into Delft FEWS will not only give them more time to properly analyse data and forecast results, but it will also allow them to more readily adopt new data sources and advanced models, including for example seasonal outlooks.  The implementation of Delft FEWS at EBY started in April of this year, with the objective to develop an initial pilot installation scheduled to be completed by November. In a second phase, this will be developed further into a fully operational Delft FEWS system in 2019. A third phase is also planned, focussing on new innovations and services. In implementing Delft FEWS at EBY, significant attention is given to knowledge transfer to the EBY hydrologists. Half of the team is in Delft this September for training, while the other half is operating the dam. They will then switch places in October, when the other three team members will come to Delft to receive training, and those already trained to operate the Dam in expectation of the operational Delft FEWS system become available next year.

For more details contact:

Jan Talsma (

Rodolfo Alvarado Montero (

Micha Werner (