PACIFICORP - CASE STUDY
Real-Time Flow Data for the North Umpqua Hydroelectric Project
The North Umpqua Hydroelectric Project, located on the west side of the Cascade Mountains, consists of eight powerhouses, eight dams, and 44 miles of waterway (canals and flumes) along the North Umpqua River, Clearwater River, and Fish Creek. The combined rated capacity of the project is 185,500 kW. All project plants are operated from the Toketee Control Center1 in Toketee Village near the Toketee and Fish Creek power plants.
REQUIREMENTS
In 2000, PacifiCorp agreed with the Oregon Water Resources Department on a schedule for bringing the North Umpqua Project into compliance with licenses that specify maximum diversion from each natural stream as well as minimum flows to be maintained in bypass reaches (natural streams) below project diversions. The agreement stipulated a gaging system to account for all project diversions and bypass flows. Discharge data from the canal gaging system and penstock flowmeters were to be reported to the District 15 Watermaster’s Office in Roseburg, Oregon, on a daily basis. Flow information from bypass reaches was to be reported daily beginning in 2002.
The project had two phases. Phase I provided for monitoring flows in canals (by datalogger) and penstocks (by ultrasonic flowmeters). Reports were generated by operators who acquired data from the logger network and the penstock flowmeters. Phase 2, to be completed by October 31st of 2002, added monitoring of bypass reaches and bring all of the data to the Toketee Control Center by means of a radio network. A computer system allows operators to monitor flows in real-time and automates OWRD report generation.
OWRD Requirements:
- Gages meet applicable United States Geological Survey (USGS) standards.
- Rating tables for each gage were developed from current meter measurements over the range of expected canal flows.
- Each rating is verified annually to ensure accuracy.
- Discharge data from the canal gaging system and penstock flowmeters is reported to the District 15 Watermaster daily (2001).
- Flow information from bypass reach USGS gages is reported daily (2002).
THE PROBLEM
Because the area is mountainous with canal and river sites scattered over a 100 square miles, flow monitoring for North Umpqua presents challenges Bypass reaches are in areas difficult to access, even on foot. Sites are often surrounded by tall trees, inhibiting communications and preventing use of solar panels for power. Access is primarily via dirt roads, barely passable in bad weather. Visiting each site daily requires heavy manpower (about 4 hours for a complete circuit). A water right or flow violation could go undetected for days. Viewing flow conditions in real-time is critical.
THE SOLUTION – PHASE 1
Monitoring canal and river flows requires sophisticated expertise Survey to recommend a vendor. Sutron Corporation was recommended. Sutron and PacifiCorp focused on canal sites in 2001 (Phase I) and completion of the entire system by October of 2002. ODWR Phase I requirements were met by placing permanent gaging stations near the downstream ends of major canals, using data loggers (without telemetry) that read flow directly (flow depth vs discharge rate) and that stored flow data. Real-time flow data required a communications network. PacifiCorp had in place a variety of hard-wire and fiber optic links and had conducted experiments with line-of-site radio. PacifiCorp's access rights to an existing radio repeater site at Cinnamon Butte to the east of the project area were an integral part of the solution. A complete radio path survey to facilitate design of the communications network for Phase 2 was completed in September, 2001.
THE SOLUTION – PHASE 2
The Phase 1 monitoring system was in place by October 31, 2001 and the communications path survey to determine the exact combination of radios, repeaters, and other links needed to bring data back to the Control Center was finished. The final communications system including dataloggers and communications for the bypass reach sites were implemented. The penstock flow meters were integrated into the telemetry network. When the entire computer system and software have been incorporated, operators will access a computer that stores canal and stream gage ratings, easily updated if changes are indicated by the stream gaging program. Ratings are used in real-time to convert the telemetered stream and canal stages to flow. Stage reading and flow values are stored in a relational database with a 6 onth storage time for telemetered stage values and computed flows.
A process to automatically generate OWRD flow reports with tables showing site-specific stage and flow measurements at a specific time of day stores this data on the system hard drive. A graphical man-machine interface (MMI) aids operators in station setup and interpreting data. Trained personnel use the MMI to change station characteristics as well as add or remove stations.
The primary operator display resembles a spreadsheet that contains a list of system gaging points and the current stage and flow. The display updates in real time.The table will update every 15 minutes (interval set by agreement with OWRD). Stations whose report times are more than 20 minutes old are marked by yellowed time panels. Stations whose report times are more than 1 hour and 10 minutes old are marked by red time panels. Yellow and red marked time panels alert the operator to any problems with telemetry.
The table will also provide water right and low flow alerts. When flow exceeds the water right for the site, the flow value will be changed to blinking red and the amount of the alert will be presented in a separate “alert” window at the bottom of the table. Similarly, the system will warn if the flow drops below the specified minimum. The design will allow for multiple alerts (alerts at more than one site.)
SUMMARY AND CONCLUSIONS
PacifiCorp’s real-time flow monitoring network will allow project operators to view the flow in system canals, bypass reaches and penstocks in real time as well as alert them when any violation of minimum flow requirements or water rights takes place. The system will use line-of-sight radio, fiber optic, and hard-wire communications technologies, data loggers, streamgaging stations, and ultrasonic flowmeters. It will save about four person-hours per day and greatly shorten response time to any flow change situation.
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