Map showing the river.
|States||Karnataka, Andhra Pradesh|
|- left||Jayamangali, Kunderu, Sagileru|
|- right||Chitravati, Papaghni, Cheyyeru|
|- location||Utukuru into Bay of Bengal, Nellore, Andhra Pradesh, India|
|- elevation||0 m (0 ft)|
|Length||597 km (371 mi)|
|Basin||55,213 km2 (21,318 sq mi)|
|Discharge||for Nellore (1965-1979 average), max (1991)|
|- average||74.3 m3/s (2,624 cu ft/s)|
|- max||1,876 m3/s (66,250 cu ft/s)|
|- min||0 m3/s (0 cu ft/s)|
The Penner (also Pennar, Penna or Penneru) is a river of southern India. The Penner rises on the hill of Nandi Hills in Chikballapur District of Karnataka state, and runs north and east through the state of Andhra Pradesh to empty into the Bay of Bengal. It is 597 kilometres (371 mi) long, with a drainage basin 55,213 square kilometres (21,318 sq mi) large.
This river basin occupies nearly 55,213 km2 area. Pennar is an interstate river with 6,937 km2 and 48,276 km2 river basin area located in Karnataka and Andhra Pradesh respectively. The river basin receives 500 mm average rain fall annually. The river basin lies in the rain shadow region of Eastern Ghats.
The watershed of the Penner and its tributaries covers part of the southern Deccan plateau, including most of the Rayalaseema region of Andhra Pradesh and part of Karnataka. The Kolar Plateau forms the divide between the Penner watershed and those of the Kaveri, Ponnaiyar, and Palar rivers to the south. The Penner drains the northern portion of the plateau, which includes parts of Kolar and Tumkur districts in Karnataka. The Krishna River and its tributaries drain the Deccan plateau to the west and north of the Penner's watershed, and the low Erramala hills forms the northern divide of the Penner basin. The upper watershed of the Penner includes Cuddapah District, central and eastern Anantapur District, the southern part of Kurnool District, northwestern Chittoor District. The main tributaries of the Penner are the Jayamangali, Kunderu and Sagileru from the north, and the Chitravati, Papaghni and Cheyyeru from the south. The Penner then flows east through a gap in the Eastern Ghats ranges onto the plain of Coastal Andhra, flowing through Nellore city before it empties into the Bay of Bengal at a place called Uttukuru, 15 km east of Nellore.
The estuary of the Penner river extends 7 km upstream from the Bay of Bengal. Tidal influence and salt water extends further upstream during the November to June dry season. Coastal dunes as high as 7 meters form around the river mouth. Upputeru tidal creek, 15 km in length, and Isakapalli lagoon, separated from the Bay of Bengal by the Isakapalli barrier island, 180 m long and up to 3 m high, form the main coastal wetlands.
The Penner basin has a dry tropical monsoon climate. The upper basin of the Penner is semi-arid, with summer temperatures of 25–46 °C and winter temperatures of 18–28°C. Most of the rainfall is provided by the moisture-bearing southwest monsoon, which provides rain to most of India between June and September. The Penner basin lies in the rain shadow of the high Western Ghats ranges, which prevents much moisture from reaching the region. Post-monsoon cyclonic storms in the coastal region produce additional rain during September and October. The winter northeast monsoon, which provides rain between December and March, provides little rain to the upper basin and slightly more to the lower basin. It varies greatly from year to year in south India, sometimes bringing powerful cyclonic storms with flooding and high winds. The mean annual rainfall is 550 mm/year in Anantapur, and 900 mm/year in Nellore. The Penner basin suffered from a prolonged drought in the 1990s, which caused much misery among the regions farmers and generated political demands to build an aqueduct to bring water from the Krishna River to Rayalaseema.
The upper basin was formerly covered by tropical dry forest, thorn forest, and xeric shrublands. Most of the dry tropical forest has now disappeared, due to clearance for grazing and overharvesting the forests for timber and firewood, replaced by thorny shrublands. The remnant forests of the Deccan are largely deciduous, dropping their leaves in the dry winter and spring months. The East Deccan dry evergreen forests of Coastal Andhra were evergreen, but these forests have largely been reduced to tiny remnant pockets.
The small boat port of Krishnapatnam lies on Upputeru creek, and was planned to be developed into a deep-water port by 2006. Buckingham Canal, a navigable man-made waterway that runs just behind the coast, allows small boats from the Penner to get to Chennai in the south and the Krishna River delta to the north.
Telugu literature has flourished in the Penner basin which produced several well-known authors and poets. Raallapalli Anantha Krishna Sharma, Vidvan Vishvam, and C. Ramakrishna Reddy are noteworthies among them. Vidhvan Vishvam's penneti paata which means "a song of River Penna" is very popular in Andhra Pradesh and in Raayala Seema in particular. Ramakrishna Reddy's "penneti kathalu" represented the tragic and cultural life of the people of Penner valley. These stories are credited to be the best of their kind with the accent of local language presented effectively.
Water use potential 
The average annual water yield in river is nearly 6.316 billion cubic meters. All the water sources in the river basin are fully harnessed by constructing nearly 5 billion cubic meters capacity water storage reservoirs. Ground water is also extensively harnessed in the river basin beyond the long term sustainability.
The predominant rain fall is during North East Monsoon season whereas it is in South West monsoon in the adjoining Krishna river basin. This basin is situated geographically at lower elevation compared to the surrounding Krishna river basin. This feature facilitates water transfer from the adjoining Krishna basin. Water can be transferred from the adjoining Krishna basin in to Pennar basin up to 600 m MSL elevation with moderate water pumping (less than 100 m head). The river basin has extensive rain fed agriculture lands and good water storage sites for its all around development provided Krishna river water is imported to the basin. The monsoon flood waters of Krishna river during South West Monsoon months can be transferred for direct use in Pennar basin without the need for water storage.
Interstate aspects 
The Pennar basin water apportionment is governed by colonial time water sharing agreement in the year 1892 and the Interstate River Water Disputes Act 1956. However the future development of Pennar basin depends on Interstate water sharing agreements of Krishna river. Tungabhadra Dam which is located in Karnataka and a joint project of Karnataka and Andhra Pradesh, is the only gate way to transfer water from Krishna river to the uplands of Pennar basin up to 600 m MSL. The low lands of Pennar basin can be supplied with Krishna river from the Srisailam dam up to 250 m MSL. The outcome of ongoing Krishna Water Disputes Tribunal – II is very crucial for the future of Pennar river basin.
See also 
- Garg, Santosh Kumar (1999). International and interstate river water disputes. Laxmi Publications. pp. 7–8. ISBN 978-81-7008-068-8. Retrieved 16 May 2011.
- Raayala Seema Mukhachitram published by Seema Sahithi
- 1892 Agreement - pages 279 to 293
- Interstate river water disputes act - 1956 and its legal provisions
- Blue Print for Godavari River Water Utilization in Andhra Pradesh
- Review of Krishna Water Disputes Tribunal - 2 report
- Chisholm, Hugh, ed. (1911). "Pennar". Encyclopædia Britannica 21 (11th ed.). Cambridge University Press. p. 104.