Briefing of Jiangya Dam

　　In order to accelerate the harnessing of Lishui River, to tap its water resources and to develop economy in the basin, Ministry of Water Resources, People's Republic of China (MWR) and Hunan Provincial Government (HPG) jointly established Lishui Hydro and Power Corporation (LHPC) in 1992, which is responsible for the construction, operation and management of water and power projects and related economical projects in Lishui River basin within Hunan Province.

　　Located in the middle reaches of Yangtze River, the Lishui River, with a total catchment area of 18,583km2, a total length of 390km and a drop of 1439m, extends across Hunan and Hubei Provinces. A total of 26 cascade projects are to be built on its main stream and tributaries. Jiangya Project is the first one built by LHPC.

　　Jiangya Dam is located in the middle reaches of Loushui River, a tributary of Lishui River, 57km away from Cili County, Zhangjiajie Prefecture, as the first critical flood control project on the Lishui basin. The catchment area above Jiangya damsite is 3711km2, the reservoir, being of one-storage, has a total storage capacity of 18.55〜106m3, out of which, 740〜106m3 for flood routing with a

GENERAL LAYOUT

dead capacity of  410〜106m3 and a normal water level of 236.0m. After completion, the downstream flood protection level will be of 17-20 year frequency instead of 4-7 year frequency currently, which can greatly ease the flood control pressure in the Lishui Basin and western Dongting Lake; the reservoir irrigates 85,000mu of farmland, improves 124km of river course, and provides more than 5000 persons with water supply. In addition, adjacent to the world-famous Wulingyuan scenic spot, Jiangya Dam will become a new tourist spot.

LONGITUDINAL SECTION OF POWER HOUSE 　　Jiangya Dam, with a crest at E1. 245.0m, max. height of 131m and crest length of  369.8m is the highest full-section RCC gravity dam in the world of its kind at this time. The total dam concrete volume is 1.37〜106m3, of which 1.10〜106m3 for RCC. The spillway blocks are aarranged in the middle of the river bed with 4 crest spillways and 3 mid-level outlets. The high-low bucket is used for energy dissipation by means of  big differential deflecting collision when the crest spillways and mid-level
outlets discharge flood jointly. The Mid-level outlets discharge flood of 1700m3/s corresponding to 100-year   frequency flood or below; mid-level outlets and crest spillways jointly discharge a max flood of 11700 m3/s above 100-year frequency flood.

　　The powerhouse is built inside the mountain body on the right bank, the diversion system with a tower-shaped intake adopts one penstock to one unit layout with 3 parallel power tunnels in total, one tunnel has an internal diameter of 6m and a length of 158.04m. The main powerhouse has excavation dimensions of 108.5m〜20m〜46m (L〜W〜H), with a total installed capacity 3〜100MW, a design head of  80m, a flow rate of 141.39 m3/s for a turbine. The units can produce energy output of 756GW·h per year.

　　Jiangya Dam project, as the national key project, commenced with its main


RCC fULL-Face Placement
body works in July, 1995 and was completed essentially by the end of 1999, has a total investment of 3313.72〜106 RMB yuan, of which 1.0〜109 RMB yuan from MWR and HPG, respectively, in addition to banks' loan (of which 97〜106 USD from the World Bank).


Deep-chute high-speed belt & Concrete Vacuum-chute convey system

 　　During Jiangya RCC Dam construction, on the basis of  full application of the up-to-date RCC construction technology, the dam contractor creatively developed a new RCC construction technology--Inclined-layer concreting method which made the concrete have an equivalent construction quality with some indexes more excellent in comparison with the traditional horizontal-layer concreting method, increased the construction efficiency and decreased the cost. A total of 455〜103m3 volume RCC was placed with the new technology, which had laid a foundation for the completion 8 months ahead of the schedule. In order to solve the difficulties of concrete haulage in the middle of the dam and above caused by the canyon

topography at the damsite, a joint transportation system consisting of deep-chute & high-speed belt conveyan facilities and vacuum chutes was set up to convey concrete in great scale, resulting in economic and efficient transportation. The application of enriched & vibrated RCC (EVR) was popularized to the dam abutment and surrounding waterstops breaking through the design' limit, which not only ensured the construction quality and simplified the construction craft but also speeded up the construction. Officials from the World Bank and the experts from both at home and abroad highly appraised Jiangya RCC Dam construction quality. The construction technology applied to Jiangya Dam has pushed forward. the RCC construction technology in China.
RCC Slope-layer Placement

RCC joint cutting


RCC core sample 6.67m long


3 units in Jiangya Underground Powerhouse


Zhangjiajie is bathed in the glow of the setting sun

　

Jiangya Project Data
No description Unit Quantity
1 Hydrology 　 　
　 Catchment Area above Damsite km2 3,711
　 Annual Inflow 106m3 4,160
　 Design Flood Discharge (P=0.2%) m3/s 12,200
　 Check Flood Discharge (P=0.02%) m3/s 15,700
2 Reservoir 　 　
　 Design Flood Water Level m 239.1
　 Check Flood Watear Level m 242.7
　 Normal Flood Watear Level m 236.0
　 Limit Water Level During Flood Season m 210.6
　 Total Storage Capacity 106m3 1,855
　 Flood Control Capacity 106m3 740
　 Dead Storage 106m3 410
3 Dam 　 　
　 Type RCC Gravity Dam
　 Max. Dam Height m 131
　 Crest length m 369.8
4 Flood Discharge Stucture 　 　
　 Crest Spillway Gate (4 gates ) Dimensions m〜m 14〜15
　 Mid-level Outlet (3 gates) Dimensions m〜m 5〜7
　 Method of Energy Dissipation Dissipation by Collision in the Air
　 Design Flood Discharge m3 9,251
　 Check Flood Discharge m3 11,700
5 Waterway System 　 　
　 Type Diversion Tunnel (3Tunnels)
　 Tunnel Internal Diameter m 6
　 Length of Each Tunnel m 158.04
6 Powerhouse 　 　
　 Type Underground Powerhouse
　 Dimensions m〜m〜m 108.5〜20〜46
　 Total Installed Capacity MW 3〜100
　 Design Head m 80
　 Firm Capacity MW 37.1
　 Annual Generation 106kW·h 756
7 Navigation (shiplift on left bank) 　 　
　 Capacity t 20
　 Length m 935
8 Irrigation (irrigation intake on left bank) 　 　
　 Irrigated Area mu 85,000
　 Water Supply Capacity person 50,000
9 Main Civil Construction Volume 　 　
　 Earth-rock Excavation m3 1,138,000
　 VCC m3 454,000
　 RCC (dam) m3 1,100,000
　 Reinforcing Steel t 3,830
10 Resettlement person 16,159
11 Total Costs 106RMB Yuan 3,313.72
12 Total Construction Duration yr 4.5