Sileru River

Sileru River is a left-bank tributary of the Sabari River in southern India. It originates in the state of Andhra Pradesh and flows through Odisha before joining the Sabari River. In its upper reaches, the river is known as the Machkund River. The confluence of the Sileru and Sabari rivers occurs at the tri-junction boundary of Andhra Pradesh, Chhattisgarh, and Odisha. After this confluence, the Sabari River continues its course, crossing into Andhra Pradesh before ultimately merging with the Godavari River.

Sileru River originates as the Machkund River in the Eastern Ghats of northeastern Andhra Pradesh. It initially flows northward before entering the Jalaput Reservoir, located along the border between Andhra Pradesh and Odisha. Downstream of the reservoir, the river assumes the name Sileru and changes its course sharply toward the southwest. It then flows through southwestern Odisha for a considerable distance before forming the interstate boundary, first between Odisha and Andhra Pradesh and subsequently between Odisha and the eastern part of Telangana. 

Throughout its predominantly southwestward course, the Sileru River flows parallel to the mountain ranges of the Eastern Ghats to its southeast. Its channel lies at an elevation of approximately 600–900 metres above mean sea level. The river eventually joins the Sabari River opposite Konta in the southernmost part of Chhattisgarh, a short distance north-northeast of the Sabari River's confluence with the Godavari River in Telangana. Hydroelectric dams constructed on the Machkund River at the Jalaput Reservoir, as well as on the upper and lower reaches of the Sileru River, constitute a major source of hydroelectric power for the surrounding region.

Since ancient times, the Sileru River has sustained the subsistence activities of indigenous tribal communities, particularly the Koya, whose presence in the region is believed to date back to prehistoric times. These communities depended on the river for fishing, foraging, and small-scale water diversion to support cultivation. Systematic exploration of the river's developmental potential began during the 1920s in the princely state of Jeypore. At that time, Maharaja Vikram Dev Varma proposed harnessing the steep gradients and substantial flow of the Machkund River near Duduma Falls for hydroelectric power generation. His initiative reflected an early recognition of the site's hydroelectric potential. 

Sileru River possesses significant potential for hydroelectric power generation, much of which has been harnessed through the development of several major hydroelectric projects along its course. These include the Machkund Hydroelectric Project, associated with the Jalaput Dam, with an installed capacity of 120 MW; the b (510 MW); the Upper Sileru Hydroelectric Project (240 MW); the Donkarayi Hydroelectric Project (25 MW); and the Lower Sileru Hydroelectric Project (460 MW). In addition, the Chitrakonda Hydroelectric Project, with a planned capacity of 60 MW, is proposed at the toe of the Balimela earth dam to utilize the hydraulic head available across the dam.

The water released from the Balimela Hydroelectric Power Station is utilized for irrigation in the Potteru tributary basin of the Sabari River in Odisha. In contrast, the water discharged from the other hydroelectric power stations along the Sileru River is generally not used for irrigation purposes, except during periods of low flow in the main Godavari River, when it contributes to meeting the irrigation requirements of the Godavari Delta. The perennial water stored within the reservoirs of the Sileru River basin also offers considerable potential for the development of irrigation infrastructure in the Uttarandhra region, thereby supporting expanded agricultural activities.

Sileru River supports a rich diversity of aquatic and terrestrial ecosystems, making it an ecologically significant river system within the Eastern Ghats. Its aquatic biodiversity is characterized by the presence of several cyprinid fish species, including the endangered golden mahseer (Tor putitora), which inhabits the cool, well-oxygenated upper reaches of the river where water temperatures generally remain below 25 degree C. Another endangered species, the Deccan mahseer (Tor khudree), is also found in the hill stream sections of the basin, highlighting the river's importance in sustaining the remaining populations of this genus in peninsular India despite increasing habitat fragmentation. 

The reservoirs constructed along the river, particularly the Balimela Reservoir on the upper Machkund reach, support a diverse fish community. Ichthyological surveys have documented between 29 and 57 fish species belonging to 12–13 families, with cyprinids such as Labeo and Tor predominating, along with catfishes and mastacembelids that have adapted to the lentic conditions created by reservoir impoundment. 

The river also contributes significantly to the terrestrial biodiversity of the region through its gallery forests and floodplains, which provide habitat for a variety of wildlife characteristic of the Eastern Ghats. These habitats support mammals such as the Indian crested porcupine (Hystrix indica), civets, and numerous bird species associated with riverine ecosystems. The Sileru basin is further enriched by the diverse flora of the Eastern Ghats, which comprises more than 2,000 vascular plant species, including several endemic taxa restricted to inselberg and plateau landscapes. Faunal endemism is also evident among selected invertebrates and reptile species, reflecting the ecological value of the basin's relatively undisturbed forest patches and heterogeneous landscape.