Nizam Sagar Dam is an Indian dam named after the Nizam of Hyderabad. It is a reservoir constructed across the Manjira River, a tributary of the Godavari River, between Achampet and BanjePally villages of the Kamareddy district in Telangana, India. It is located at about 144 km (89 mi) north-west of Hyderabad. Nizam Sagar is the oldest dam in the state of Telangana.

Nizamsagar dam was constructed in 1923 by Mir Osman Ali Khan - the 7th Nizam of the erstwhile Hyderabad State. It was made by emptying over 40 villages length:3 km (1.9 mi).^{[citation needed]}. The dam has an effective storage capacity of 724.9 Mcm (million cubic meters) or 25.6 tmc ft

Before Nizam Sagar was built, the Manjira River was not properly harnessed and little water was being used by diverting water at Ghanpur Anicut for Irrigating about 5,000 acres (2,000 ha) and an open Channel called Mahaboob Nagar (Right Canal) in Medak District. The Ghanpur Anicut was the first scheme constructed across Manjira river in 1904 at a cost of Rs.18.00 Lakhs. Some years later, Nawab Ali Nawaj Jung Bahadur as Superintending Engineer added Fatch Nahar (Left canal) to increase the utility of the river later. The ayacut of 17,308 acres (7,004 ha) was being irrigated under this Ghanpur Anicut that subsequently increased to 30,000 acres (12,000 ha) as per actuals.

Nizam sagar Project is the second irrigation scheme on Manjira river and the largest in the then Hyderabad state taken up during the year 1923 and completed by the year 1931. This Project was originally contemplated for utilization of 58.00 TMC of water to irrigate275,000 acres (111,000 ha) acres in Banswada, Bodhan, Nizamabad and Armoor Taluks of Nizamabad District. After reorganization of States in 1956, the Manjira basin was distributed among the three states viz., Maharashtra, Karnataka and Telangana.

Different irrigation schemes have come up in above three states. Some of them to mention are:

Manjira Barrage and Singur Project in Telangana to meet the drinking water needs of twin cities of Hyderabad and Secunderabad in Telangana.

Karanja Project, Choukinala Project in Karnataka, Lower Tiruna Project, Manjira Project in Maharashtra State. Therefore, the inflows into Nizamsagar Project and as well as the low flows at Ghanpur Anicut during lean periods have dwindled considerably. Added to this the silting of reservoir has been at greater pace than designed for. From the investigation conducted by the A,.P.E.R.L. (Andhra Pradesh Engineering and Research Laboratories) Hyderabad in 1973, it was shown that the capacity of 29.7 TMC at original FRL of RL + 1,400.50 ft (426.87 m) has been reduced to 11.8 TMC. In the remodeling proposals F.R.L. has been raised from +1,400.50 ft (426.87 m) to +1,405.00 ft (428.24 m) and the capacity at this new FRL of + 1,405.00 ft (428.24 m) is 17.80 TMC.

Apart from the above changes, out of the total localized ayacut of 275,000 acres (111,000 ha), 28,085 acres (11,366 ha) have come under submergence of Sreeramsagar Project, 8,296 acres (3,357 ha) have come in the command of Lakshmi canal and Kakatiya Canal of Sreeramsagar Project, and 7,260 acres (2,940 ha) ayacut has not been getting water since inception of Nizamsagar Project. Thus, the settled ayacut of 275,000 acres (111,000 ha) has come down to 231,339 acres (93,620 ha).