Ribeira Seca (Santiago)

Ribeira Seca
The stream at the Poilão Reservoir
Country	Cape Verde
Physical characteristics
Main source	near Pico da Antónia Santiago Island, Cape Verde 1,000 m (3,300 ft)
River mouth	between Achada Fazenda and Pedra Badejo 15°04′13″N 23°33′50″W / 15.0703°N 23.5638°W / 15.0703; -23.5638
Length	17 km (11 mi)
Basin features
Basin size	25 km2 (9.7 sq mi)

Ribeira Seca are two of the longest streams of the island of Santo Antão in Cape Verde. The stream flows south in the southern interior and is about 17 km in length, they run in the municipalities of São Lourenço dos Órgãos and Santa Cruz. The stream has some tributaries. During dry days especially in the Spring and Summer, the stream is predominantly dry.

The river is mainly dry during dry seasons as the river is named after along with many other streams on the island.

The stream as Ribeira de Pico da Antónia starts near the area of Pico da Antónia, the island's tallest summit at an elevation of about 1,000 meters, the stream flows down the slopes and lower at the elevation of about 500 meters at Temerosa (also Pico da Antónia village), it flows eastward forming its own valley known as Órgaos, Ribeira Seca or the Interior, for the first 5 km, it runs within the Praia-Assomada-Tarrafal Route (EN1-ST01) and flows at João Teves, the road with São Jorge dos Órgãos has its river crossing (300 m elevation), it also has a crossing with that route flowing underneath the highway (250 m elevation) and the stream flows within EN1-ST03 (João Teves-Achada Fazenda/Pedra Badejo). The stream flows near Levada dos Órgãos and Poilão, in that area, the river flows into the nation's first reservoir, Barragem de Poilão at the elevations of about 210 and 180 meters. The stream flows over the dam to the creekbed and from there flows northeast. After, the stream flows to the north and west of Achada Fazenda, it flows under a bridge that has the Praia-Calheta-Tarrafal Route (EN1-ST02) and empties into the Atlantic southeast of Pedra Badejo in the east of its small beach.

During the Ice Age, the stream was about a kilometer longer and was 18 km it shortened to 17 km around 2000 BC.

Before the island and the stream were explored by António da Noli in 1460, its landscape were forested and had shrubs in the area, the eastern part is unknown. The area was first settled by settlers and much of its slaves around the early 16th century. The map of the stream was depicted in the 1747 French/Dutch map by Jacques Nicolas Bellin. From around the 19th century to 1971, the stream flowed entirely in the earlier Praia and was the municiipality's longest and from 1971 to 2005, it flowed in all of the municipality of Santa Cruz and was its longest.