The town sits at the southwestern edge of Goiás, right where the state meets Minas Gerais. Before 1930, this stretch of the Paranaíba was almost empty - just diamond miners and fishermen in a small settlement on the riverbank. The 1935 bridge started a slow build. By the time the waters washed it away in 1957, the population had reached about 7,000. After Kubitschek's 1961 replacement bridge, the next transformation was already being planned upstream: a major hydroelectric project that would require moving the old town entirely. When the dam opened in 1975, the government built a new city for 10,000 people, with paved streets, mercury lamps, and modern schools.

The São Simão hydroelectric plant began operating in 1978 with an installed capacity of 1,710 MW across six generators. The dam holds back a reservoir with a useful volume of approximately 5.5 billion cubic meters. ANEEL, Brazil's electricity regulator, authorizes the reservoir to operate between 390.5 meters (minimum operating level) and 401 meters (maximum). The structure is one of the most impressive engineering works on the Paranaíba, and much of São Simão's municipal income still flows from the electricity it generates. The town of roughly 14,000 people sits downstream, catching the economic spillover from its own giant.

Praia do Lago Azul - Blue Lake Beach - stretches a kilometer along the reservoir's edge, lined with bars, showers, a bike path, bathrooms, and tropical vegetation. The beach is entirely artificial - it did not exist before the dam - but nobody treats it as fake. Fishing, swimming, water-skiing, jet-skis, and small sailboats fill the surface during summer weekends. The hotel infrastructure is unusually deep for a town this size: 18 hotels and a major campground on the lakeshore, supported by 15 restaurants. Carnival in São Simão pulls major performers from across Brazil and tens of thousands of visitors, and the town's economy leans on those few intense weeks as much as on the power plant.

São Simão is officially a port on the Paranaíba River and a key link on the Hidrovia Paranaíba-Tietê-Paraná - a continuous navigable waterway system that connects central Brazil to the Atlantic via the port of Santos. Barges carrying soybeans, grains, sand, gravel, and sugarcane move out of public and private warehouses here and travel thousands of kilometers south. The regional airport has a paved runway 1,800 meters long and 45 meters wide, capable of handling aircraft up to 99 tons. Highway connections run in every direction: BR-365 to the Triângulo Mineiro and São Paulo, BR-364 to Mato Grosso, GO-060 and GO-164 toward Goiânia and Brasília 365 kilometers away.

The numbers stay modest. Population in 2007 was 13,832, up from 11,374 in 1980 - roughly 2,450 new residents across 27 years. The cattle herd runs about 40,000 head. Rice and corn are the main field crops. There are 19 industrial establishments, 192 retail businesses, and one automobile for every 9.45 residents. The adult literacy rate of 85.1% sits just below the national average; the infant mortality rate of 28.9 per thousand is slightly better than the national figure. The Municipal Human Development Index is 0.754 - mid-range for Brazil, and respectable for a town whose economy runs on a dam, a river, and a carnival.

From the air, the lake dominates everything. The reservoir's curving shoreline cuts through the flat cerrado countryside in a long irregular ribbon, with the dam itself forming a white-gray line 3.6 kilometers long at the southern end. The old town disappeared under water when the dam filled; the current town sits on slightly higher ground nearby, its grid of paved streets laid out in the 1970s relocation plan. Highway BR-364 runs out east toward Minas Gerais across the new Paranaíba crossing. The beach, when it's busy, shows up as a bright thin strip of disturbed water. And somewhere in the shadows of the dam's spillway are the diamond miners' first campsites, now a hundred meters underwater, remembered only by the people who used to fish where the river used to flow.