Alvito – Pisão Canal

Beja, Portugal

Client

EDIA, Empresa de Desenvolvimento e Infra-estruturas do Alqueva, S.A.

Location

Beja, Portugal

Date

2006 - 2008

Status

Completed

The project, integrated into the Alqueva Multi-purpose Primary Irrigation System, comprised the construction of Sections 1, 2 and 3 of the Alvito–Pisão Canal, located in the district of Beja, within the municipalities of Alvito and Cuba. The canal extends from the Water Intake at the Alvito Reservoir to the ER 5 / Cuba-West Reservoir, over a total length of approximately 20.17 km.

The project comprised three consecutive sections, arranged as follows:

- Section 1: Alvito Dam – Barras/Odivelas Hydraulic System;

- Section 2: Barras/Odivelas Hydraulic System – Vidigueira Conveyance Pipeline;

- Section 3: Vidigueira Conveyance Pipeline – Cuba-West Reservoir (R1);

It included the following main infrastructure elements:

- Nine canal sections with a trapezoidal cross-section, with a total length of 18 702 m;

- Three covered rectangular sections, constructed using the cut-and-cover method, with a central dividing wall and a total length of 265 m;

- Three inverted siphon sections, comprising three DN 2500 reinforced concrete pipelines with a steel core, with a total length of 1365 m.

The longitudinal gradient of the free-surface canal is constant at 0.196 m/km. The side slopes of the trapezoidal canal have an inclination of 1V:1.3H.

The project also covered the construction of various complementary structures:

- Water intake at Alvito Dam;

- Offtake to the Barras–Odivelas Hydraulic System;

- Offtake to the Cuba–Vidigueira conveyance pipeline;

- Offtake to Reservoir R1 (Cuba-West);

- Regulation structures;

- Emergency spillways;

- Culverts;

- Overpasses for pedestrian, vehicle and livestock crossing;

- Rescue ramps and access to the canal;

- Wildlife crossings;

- Service roads, fencing and gates.