Khanki barrage

Khanki BarrageIntroductionKhanki Headworksis aheadworkssituated on theRiver ChenabinGujranwala Districtof thePunjabprovince ofPakistan. It was constructed in 1889 and is considered to be the oldest headworks in Pakistan.Khanki Headworks is used for irrigation and flood control. It is also used to provide water to tributaries such as theLower Chenab Canal,[1]which originates from Khanki Headworks. Khanki controls water distribution over 3 million acres (12,000km) of agricultural lands by one main distributary, theLower Chenab Canal, and 59 minor distributaries.Overview The weir was constructed during 1889- 1892 It was the first weir in Punjab founded on alluvial sandy bed of river It was designed and constructed under conditions of extreme economy The weir got repeatedly damaged in portions and had to be remodeled extensively during 1919- 1920 and 1933- 1935 The weir originally was a shuttered type weir comprising 8 spans of 500 ft each, left undersluices (12 No. 20 ft each) and canal head regulator (12 spans of 24.5 ft each) With the extensive remodeling during 1933- 35, the weir now comprises (left to right): Left Undersluises (12 No. 20 ft. each) Three weir bays (1423 ft) Central undersluices (18 No. 20 ft each) Three weir bays (1545.75 ft) Right Undersluices (18 No. 20 ft each) Total width between abutments 4386 ft Waterway 3928.75 ft Head Regulator of Main Weir ofLower Chenab CanalKhanki Barrage

Salient Features of Khanki BarrageLocationYear of Const.TotalLength/ Clear WWDes. Q(cfs)Off- take (lower chenab canal)

Water Allowance(cfs/1000 acres)CCA (ma)Des. Q (cfs)Length (Canal Miles)

MainBranchDistys.Total

Sixteen (16) KmDown stream of Alexandra railway bridge, near WZD, Distt. GWA18924,386/ 3,9298000002.84(P)5.15(NP)3.031(Dsitt. Gujranwala Hafizabad, Shiekhpura, Nankana, Faisalabad, Jhang & T.T.Singh)11,600404142,3992,853

New Khanki BarrageReasons for ConstructionReplacement of existing headworks with a new barrage 900 feet downstream is proposed on the following basis: Severe aging effect; Capacity constraint; Lack of effective control on river regulation; Inefficient and insufficient physical communication between the two banks; Mixture of several out dated design & construction techniques; dismantling & rebuilding operation if existing structure remodeled; Gates installation impossible in existing weir; and Inadequacy of existing weir for automation.Recommendations for New Barragei. A new modern barrage, 900 ft downstream of existing weir and incorporating an AR Bridge.ii. New head regulator of L.C.C.iii. Re-aligned head reach of L.C.C originating from new head regulator and joining existing LCC at RD 5.iv. Improvement of roads on bothriver banks, buildings and other infrastructure.v. Rehabilitation of River Training works.

Salient Features of New Barrage Main weir55 bays @ 60 ft. each Undersluices10 bays @ 60 ft. each Silt excluder in first two bays of left undersluice 8 tunnels LCC head regulator6 bays @ 30 ft. each Bridge on main barrage 4384 ft. Bridge on head regulator 215 ft. Radial gates for barrage 65 Nos (60 ft wide each) Radial gates for LCC head regulator 6 Nos (30 ft wide each) Two fish ladders (left and right) 215 ft. Two divide walls (left and right) 342 ft. Two guide banks (left and right) 1737 ft. Instrumentation Vibrating wire electronic piezometers 96 Nos. Stand pipe piezometers 12 Nos. New canal link for connection with existing L.C.C 5000 ft. Improvement of existing approach roads 35 Km Sloping studs on left side downstream of new barrage 04 Nos. Construction of New Khanki Barrage