Projects

Sweetwater Authority SCADA System

• Study

• Phase 1 Design and Construction Support

• Phase 2 Design and Construction Support

Sweetwater Authority Chula Vista, California

Sweetwater Dam at Loveland Reservoir

Timberline Engineering’s project team performed a study for Sweetwater Authority involving replacement of an obsolete data acquisition system serving water treatment plant processes and upgrading aspects of the plant process control. The study also recommended phased implementation of SCADA and telemetry systems for the Authority’s widespread water production, storage, transmission and distribution facilities. Timberline also performed a study of radio telemetry options and recommended spread spectrum radio in the 902-928 MHz band as the media for reaching various facilities of the water distribution system.

Upon completion of the study phase, Timberline designed the water treatment plant system and provided support through bidding, system integration, construction and testing.  This first phase of this project established the Authority’s baseline SCADA system. The system included a new SCADA master station with dual-redundant CPUs (at the 30 mgd Perdue Water Treatment Plant), dual-redundant Modicon Quantum PLC FEP, LAN interface equipment, and dual operator workstations (each with two 21-inch monitors). The project also included control room remodeling, operator console, programmer workstation, loggers, printers, dial-up modems, and Modicon Compact PLCs to support various plant processes and subsystems. Connection of PLCs to the FEP utilized a plant-wide cable system and the Modbus and Modbus+ communication protocols.

As this was a phased upgrade to the water system controls, the master station was required to serve all of the Authority’s existing, new and future water supply, treatment, storage, transmission and distribution facilities. Initially, the SCADA system controlled processes at the Perdue Plant and interfaced to the control system at the new Demineralization Facility. This project also included an engineering workstation at the Authority’s Administration Building, connected via an existing T1 WAN, plus various routers, servers, loggers, printers, and dial-up modems. PLCs were used at the raw water pumping station, the Sweetwater Reservoir Dam, the plant chemical feed and storage building, the particle counters and four filters. The project included integration of operator interfaces and PLCs for the existing Sweetwater Reservoir Urban Runoff Diversion System. The work was sequenced to minimize the impact on plant operations.

As construction on the treatment plant SCADA system was underway, Timberline designed a second phase of the project to include 42 water distribution facilities in the SCADA system, each with a PLC-based RTU and spread spectrum radio telemetry. This phase will also add a workstation at the Authority’s Operations Center in Chula Vista. Phase 2 of the SCADA system project is currently in construction.

The SCADA system provides security functions by monitoring doors to facilities and hatches on water tanks. Intrusions are alarmed and logged at the Control Center. The remote terminal units were programmed to allow authorized individuals access to the site and to allow temporary access to other authorized visitors to the site.

Timberline has recognized that substantial project savings and improved project quality are possible by improving communications between the Contractor, Engineer, and Owner during construction. To realize these benefits, Timberline developed and is hosting a web site providing conformed specifications and drawings, field orders, responses to RFIs, submittal review comments, and the project submittal log. This central repository for project communications has ensured that all members of the team have access to the most current project information.