The Mlava represents the main river flow, the hydrographic artery of Homolje. It arises from the strong Žagubica spring, and about 150 m downstream, it merges with the Tisnica River which dries up during summer. The flow of the Mlava can be divided into three catchment areas: the upper region – Homolje, the middle region – Mlava, and the lower region – Stig.
The Mlava starts its watercourse from the basin of Žagubica. After flowing for 11,5 km, it leaves the plane basin near the village of Izvarica and enters the epigenetic Gorge of Ribare. Its course through Ribare gorge is 9,5 km long. When it leaves Ribare gorge, the Mlava flows for about 7 km through the Krepoljin - Krupaja basin in order to enter Gornjak gorge. Then, after flowing for about 16 km through the Gorge of Gornjak, the Mlava leaves the territory of Homolje. The Mlava cut three meanders in the Gorge of Ribare, while it cut four of them in the Gorge of Gornjak. The total length of the Mlava’s watercourse through Homolje is 44 km, while its length to the mouth of the Danube is 158 km long. The streamflow values of the Mlava differ based on the atmospheric precipitation and the snow break in the nearby mountains. The highest streamflow is in April and the lowest is in September. The greenery along the river, as well as the flora found in it, affect the color of the Mlava and, therefore, it is greenish. Different species of fish can be found in the Mlava, but the most famous is the Mlava trout. Besides the mentioned trout, three other species abound in the Mlava: common nase, chub, and gudgeon. The Mlava River managed to preserve the characteristics of a clean mountain river in its course through Homolje. However, the water is not drinkable because of the population that uncontrollably throws garbage into the river. This act is quite disgraceful and it must be prevented as soon as possible. The competent institutions need to engage in this matter more than they used before because we cannot permit the destruction and pollution of the greatest treasure of Homolje. The Mlava, as a tourist motif, is of great importance and it has various functions. In terms of economy, its functions are water management and hydropower. In regards to the tourist attraction and recreation, the following can be enumerated: the springs, the gorges, the fishponds, the sport fishing, and the recreational ambience. In certain regions of the valley, the recreational values of the river are intensified by the means of peaceful landscapes on the banks which are suitable for picnics and sports activities. The most beautiful parts of the Mlava’s course through Homolje represent the gorges and the cut meanders. A true peculiarity is a part of Ribare gorge where the fast and nosy Mlava made an almost rounded meander. That meander, among the cliffs, is the location of a beautiful village called Ribare, the most beautiful corner for rural tourism.