Ghaggar-Hakra River

The Ghaggar is an intermittent river in India, flowing during the monsoon rains. It originates in the Shivalik Hills of Himachal Pradesh and flows through Punjab and Haryana to Rajasthan; just southwest of Sirsa in Haryana and by the side of Tibi in Rajasthan, this seasonal river feeds two irrigation canals that extend into Rajasthan.
The Ghaggar-Hakra River is a dried out river, now consisting of the seasonal Ghaggar River in India and the Hakra riverbed in Pakistan. It is often identified with the Vedic Sarasvati River, but it is disputed if all Rigvedic references to the Sarasvati River refer to this river.
Estimates of the date at which the river dried up range, very roughly, from 2500 to 2000 BC, with a further margin of error at either end of the date-range. This may be precise in geological terms, but for the Indus Valley Civilization (2800 to 1800 BC) it makes all the difference whether the river dried up in 2500 (its early phase) or 2000 (its late phase). Similarly, for the Gandhara grave culture, often identified with the early influx of Indo-Aryans from ca. 1600 BC, it makes a great difference whether the river dried up a millennium earlier, or only a few generations ago, so that by contact with remnants of the IVC like the Cemetery H culture, legendary knowledge of the event may have been acquired.
The identification with the Sarasvati River is based the descriptions in Vedic texts (e.g. in the enumeration of the rivers in Rigveda 10.75.05, the order is Ganga, Yamuna, Sarasvati, Sutlej), and other geological and paleobotanical findings. This however, is disputed. The Victorian era scholar C.F. Oldham was the first to suggest that geological events had redirected the river, and to connect it to the lost Saraswati: "[it] was formerly the Saraswati; that name is still known amongst the people, and the famous fortress of Sarasuti or Saraswati was built upon its banks, nearly 100 miles below the present junction with the Ghaggar." (Oldham 1893: 51-52)
Ghaggar River
The Ghaggar is a seasonal river in India, flowing when water is available from monsoon rains. It originates in the Shivalik Hills of Himachal Pradesh and flows through Punjab and Haryana to Rajasthan; just southwest of Sirsa in Haryana, this seasonal river feeds two irrigation canals that extend into Rajasthan, and is thereby consumed.
The present-day Sarasvati originates in a submontane region (Ambala district) and joins the Ghaggar near Shatrana in PEPSU. Near Sadulgarh (Hanumangarh) the Naiwala channel, a dried out channel of the Sutlej, joins the Ghaggar. Near Suratgarh the Ghaggar is then joined by the dried up Drishadvati river.
The wide river bed of the Ghaggar river suggest that the river once flowed in great strength, and that it formerly continued through eastern Pakistan in the presently dry channel of the Hakra River, possibly emptying into the Rann of Kutch. It supposedly dried up due to the capture of its tributaries by the Indus and Ganges rivers, and the loss of rainfall in much of its catchment area due to deforestation and overgrazing. This is supposed to have happened at the latest in 1900 BCE, but perhaps much earlier.
In India there are also various small or middle-sized rivers called Sarasvati or Saraswati. One of them flows from the west end of the Aravalli Hills into the east end of the Rann of Kutch.