the northern slopes of the Blagaja mountain and the villages of Uzići, Rupeljevo and Rasna and enters the low Tašti field, located between the Blagaja, Krstac and Crnokosa mountains, west of the town of Požega. In the field, the Đetinja receives from the left its main tributary, the Skrapež River, but less than a kilometer after the confluence, it meets the Golijska Moravica River from the south, creating the Zapadna Morava. Since the proximity of the confluences of Đetinja, Skrapež and Golijska Moravica, some sources consider all three rivers to be direct headstreams of the Zapadna Morava. Following the direction of the course, the Đetinja is a natural headstream of the Zapadna Morava, but since Golijska Moravica is 23 kilometres longer, the latter is usually considered as the main headstream. The Đetinja's drainage area covers , it belongs to the Black Sea drainage basin. The river is not navigable. Hydroelectricity There are two small hydroelectrical power plants on the Đetinja. One is named “Pod Gradom” (“Suburban”) and is the oldest one in Serbia and on the Balkans, second oldest in Europe and third oldest in the world after Niagara in United States and was also designed according to Nikola Tesla's principles. Built only 4 years after Niagara, it was constructed by physicist , a friend of Tesla, and avid advocate of replacement of the gas light with the electric one. Decision to construct the power plant was adopted on 28 March 1899 by the shareholders of the local Weaving Workshop. The foundation stone was laid in June 1899 by King Alexander I Obrenović. The king used a specially made brass hammer, which is today part of the exhibition. The project was drafted by the engineer Aćim Stevović, while the builder was Josif Granžan, a contractor from Niš. It became operational on Saint Elijah’s Day, 2 August 1900, and is still occasionally in use, using the original Siemens engines from 1900 which were repaired in 2000. It was an enterprise of a group of Užice's industrialist, which decided to introduce the electricity in order to bust the production and lower the costs. However, the project was quite expensive. Purchase of the equipment, construction of the plant and the city grid cost 215,000 dinars in silver. The equipment was shipped by train from Berlin to Kragujevac, and then by carts through the muddy roads to Užice. The half-automatized plant produces 40 to