Jingtai Irrigation Scheme (Gansu Province, China)
The Jingtai Irrigation Scheme, a large-scale irrigation project which pumps water from the Yellow River to irrigate grain and other crops, is located in an arid region of north-central China. The project's design flow capacity is 28.3 cubic meters per second with an irrigated acreage approaching 66,700 hectares. The Scheme encompasses an impressive group of pumping plants, aqueducts, lined canals, tunnels, etc.
The Scheme has significant social and environmental benefits. With the project facilities nearing completion, 400,000 people from the surrounding mountainous regions have relocated to the Scheme's service area. Because of these secondary benefits, the national government pays 90 percent of the electrical costs of pumping the irrigation water.
In conjunction with the China Institute of Water Resources and Hydropower Research (IWHR) and the irrigation district, Provo Area Office staff have been consulting on low-cost automation opportunities. Selective automation at Jingtai could conserve water and help reduce pumping costs.
In November, 1999, Roger Hansen and Arlen Hilton, both of the Provo Area Office, traveled to north-central China to visit the Jingtai Irrigation Scheme. Before leaving China, they helped select two sites for demonstration automation installations: (1) a 12-VDC unit located on a major lateral and (2) a trifurcation structure at the terminus of a major canal.
In May, 2000, Arlen and Frank Woodward, also of the Provo Area Office, returned to China to complete the installation of the two demonstration units. While most of the installation work was done by the Chinese, Arlen and Frank provided technical assistance as needed.
At the 12-VDC demonstration site, a lead-acid battery is used to power the gate actuator, telemetry equipment, and datalogger/controller. The gate actuator consists of a fractional-horsepower, 12-VDC gear motor attached to the gate's gear box with chain and sprocket. A device to measure gate position and provide limit switches was also attached. The latter device was developed by Frank Woodward.
At the trifurcation structure, water is split to go in three separate directions. The first split goes to a re-lift pumping plant, the second to a desert area that the irrigation district is currently developing, and the third directs water to adjacent irrigated lands. Because of the critical nature of site, it was determined that automation was a necessity. Commercial gate actuators (Limitorque units manufactured in the United States) were installed on the three radial gates. At the trifurcation structure, all the equipment (gate actuators, telemetry, and controllers) is powered by commercial power.
Data communications for both demonstration sites are by land-line telephone. Low-cost dataloggers/controllers are used to monitor the state of the water delivery system and control the gates. The gate control software consists of a modified-PI algorithm. At both demonstration sites, the water district has a choice of two control options:
- Manual remote control
- Automatic remote control
The base station software being used is the software provided by datalogger/controller manufacturer.