01/03/2016
The preliminary works of Hub Dam, built across the River Hub, were commenced in September, 1963 and completed in June, 1981. The project was meant to construct a storage reservoir for regulating the flows of Hub River for the purpose of municipal, industrial water supply and irrigation releases to Karachi in Sindh and Lasbela District in Balochistan. The Hub Dam is an inter-provincial Project as the beneficiaries are located in the two Provinces Sindh and Balochistan. The capital cost of the project is Rs. 1191.806 million (excluding interest charges).
The total live storage of the reservoir 656,000 AF (Acre ft.) is about 2 times planned for annual withdrawal of 216,406 AF, considering Reservoir Losses (Evaporation / Seepage, 35% on average). Normally, the impounding of reservoir takes place during monsoon season. The Project is designed to supply 100 MGD (Million gallon per day) of water to Karachi (Sindh) for municipal and industrial purposes, and 15 MGD to the Balochistan industries besides irrigation of 21,000 Acres (CCA),i.e. 44 MGD, in Balochistan and 1000 acres i.e. 2 MGD in Sindh. Thus, the reservoir-release of 216,406 AF is shared by Sindh 63.3% and by Balochistan 36.7%. This supply is ensured for a period of 75 years.
Salient Features
General Purpose
: Storage of Hub River Flows for Regulated Releases of Municipal,Industrial and Irrigation uses.
Location: 45 Km North-East of Karachi City Area (Catchment 3,410 Square miles) Reservoir 29.06 Square miles (at EL. 339¢) Life of Dam 75 years Type of Dam Earthen Dam.
Main Dam: Max. Height of Dam 154¢Length of Dam 15,640¢Crest Road Level 352¢Maximum Base Width 965¢ - 8².
Saddle Dam
Max. Height of Dam 66¢
Crest Length 5,762¢
Max. Base Width 340¢
Spillway
Type Un-gated uncontrolled Concrete Ogee
Crest Length 6,020¢
Crest Elevation 339.3¢
Max. Outflow Capacity 458,000 cfs
Flood
a) Maximum Anticipated 480,000 cfs
b) Maximum Recorded 521,000 cfs
Reservoir
Full Reservoir Level 339.0¢
Maximum Reservoir Level 346¢
Dead Storage Level 276.25¢
Gross Reservoir Capacity 6, 87,276 AF (R.L. 339.3¢)
Live Storage Capacity 6, 45,470 AF (R.L. 339.0¢ to 276.25¢)
Dead Storage Capacity 41,806 AF (below R.L. 276.25¢)
Total Annual Releases 216,406 AF
The Hub Dam Canal System consists of Main Canal, Karachi Water Supply Canal, Lasbela Canal, and a Bund Murad Minor. The Main Canal, having Design Discharge Capacity of 370 cfs, off-takes from Hub Dam and bifurcates into two branches after flowing about 5.2 Miles (8.32 Km) at Head Regulator. At Head Regulator, the water supplies to Sindh and Balochistan are controlled by manually operated vertical gates. Whereas, supply to Bund Murad Minor is controlled through Lasbela Canal about one Km from Head Regulator.
At Head Regulator one branch is known as Karachi Water Supply Canal with Design Discharge Capacity of 210 cfs. This is a very sensitive canal as it supplies 20% to 25 % of the Municipal and Industrial waters to Karachi. It is a 14 Miles (22.4 Km) long open channel, which terminates at Karachi Water & Sewerage Board (KW&SB) Pumping Station near Manghopir, Karachi. It is lined with concrete tiles and crosses a number of natural drainage channels that necessitated construction of aqueducts and drainage crossings, beside a road bridge and 3 village road bridges. There are also two fall structures at this canal. The un-interrupted water is supplied through this canal at allocated rate of 100 MGD (Million gallons per day).
The second branch is called Lasbela Canal (21 Miles or 33.6 Km long) with a Design Discharge Capacity of 160 cfs supplies water for irrigation of 21,000 Acres of land and 15 MGD water for industries in Lasbela District, Balochistan. Hence a total of 59 MGD water is supplied for Municipal, Industrial, and Irrigation purposes to Lasbela District as per their allocation. The Lasbela Canal is lined canal and crosses a number of drainage channels necessitated constructions of aqueducts, siphons and drainage crossings. The total number of structures on this canal is 58. This distribution system of Lasbela Branch comprises 8 minors for irrigation purposes besides outlets for industrial water supply.
The Bund Murad Minor (handed over to Government of Sindh on 01.01.86) also off-takes from Lasbela Canal to supply irrigation water on replacement basis, to 1000 Acres of those agricultural farms which were under existence prior to the construction of Hub Dam Project.
