Hydrological Management of the Dam

1. Produce electrical energy to satisfy the contractual commitments and the increase in the national and international demand.

2. Guarantee adequate satisfaction levels from the hydrological, ecological and environmental systems on the reservoir and the valley downstream.

3. Guarantee the security of people and goods, the river’s navigability and the reduction of floods and droughts.

4. Guarantee the structural security of the enterprise.

In order to keep up with these objectives, the hydric resource must be managed based in principles of scientific order and probabilistic assessment of dangers, bearing in mind the river’s hydrological history system, the new climate change factors and the always inaccurate weather forecasts of a short and long period.

Hydric Management

The reservoir management is conditioned by a higher quota limit curve of the dam, designated as an operational safety curve, or guide curve.

This limit occurs from the dam’s maximum discharge capacity, having in account the affluent volume distributed during the critical flood period.

This rule imposes that, on the limit, a fitting capacity of around 21 Km3 is created on the beginning of January, which may allow absorbing excessive water volumes that flow in the following months, particularly in February-March-April, normally when the affluent streams are more elevated.

The application of this management criteria since the dam construction has allowed us to act, both on the control of drought minimization, and on flood minimization.

Articulation with External entities

Among the external entities, we must distinguish between the ones that exert jurisdiction on the hydric resources (DNA and ARA-Zambezi) and on the electrical production (DNE, National Electricity Department), and other government entities, from the civil service and users.

The relationship with the jurisdiction entities is defined legislated and regulated and is processed according to the normality and to the institutional cooperation. This is translated by information exchange, collaboration in matters of technical and organizational nature. In this field, the daily transmission of hydrological management data, the reports of water quality control, the predictions and simulations of exploration, the participation in the warning system and the flood alert are integrated.

Besides the jurisdiction entities, there are also basin and regional institutional entities in which HCB participates, namely the JOTC (Joint Operational Technical Committee) along with the ZRA (Zambezi River Authority), the DNA and ARA-Zambezi, the GPZ (Office of Zambezi Plan), ZESA (Zimbabwe Electricity Supply Authority), ZESCO (Zambia Electricity Supply Company), o ZACPRO6-Phase 2 and ZAMCOM (Zambezi Commission).

The Mitigation and Monitoring of Flood effects require National and Boundary Cooperation.

System of Warning and Alert

It is the organized set of human resources and technical means that have to disseminate the procedure regulations to be adopted by population through danger situations and keep the population aware of areas probably affected by the eminence of floods, the happening or the evolution of a danger situation.

The system, which is currently in use, considers the process of exploration and safety bodies within two situations: ordinary and emergency. Each of these situations considers the warning and alert that is broadcasted through radio signal messages, telephone, and fax to the jurisdiction entities (National Water Department, Regional Water Administration, Provincial Departments of Housing and Public works-Water Department) the main beneficiaries and the public in general through the local governments.

In the expected and ordinary situations, the warning of a change in the discharges is displayed 72 hours in advance.