Balance Hydrologics (and OneRain) provides the Alameda County Flood Control and Water Conservation District (District) hydrologic data acquisition and management for maintenance, operation, and monitoring since 2012 to present. The initial contract was limited to Flood Control Zone 12 (Oakland). In water year 2017, Balance expanded our role in the project, taking over operation, maintenance, and data management for total of 38 other rainfall and streamflow monitoring stations within Alameda County Flood Control Zones 2, 3, 5, 6, 7, and 12. In 2018, the District authorized a separate task to install and maintain several water level monitoring stations within the Eden Ponds tidal marsh area north of the Dumbarton Bridge. The stations were sited to monitor tidal inundation dynamics and timing within several of the ponds to better understand hydrologic conditions within the marsh during the lead-up to the spring king tides. Balan Save ce surveyed benchmark elevations at each monitoring station so the inundation extents could be converted to a standard vertical datum (NAVD88).
Under this contract, Balance calibrates, maintains, and refurbishes monitoring equipment that was installed previously by a separate consulting firm and that had been dormant for several years. Initial inventorying and rehabilitation phases will also include relocation of stations, as appropriate, to meet the evolving needs of the District. Balance established rating curves for each of the flow monitoring stations based on basic hydrologic models, FEMA flood data, and channel characteristics estimated and measured in the field, so that water level outputs from the dataloggers can be converted to flow values. Between 2011 and 2016, Balance provided field measurements of flow over a range of conditions at each of the stations to test and adjust the preliminary rating curves, and to bolster data quality. Using the on-line Contrail database, all data were monitored by Balance staff so that problems with the equipment and/or data streams could be immediately addressed. Balance provided prompt repair service for malfunctioning or non-reporting stations, so that the District’s monitoring system could be maintained at peak performance. Quality control/quality assurance procedures included periodic review and cross-correlation of data by senior hydrologists to highlight poorly-performing stations, as well as recommendations for site, equipment, and procedural improvements intended to boost data quality.
As addendum to this effort, Balance worked closely with Alameda County Public Works staff to develop a detailed grant application for the California Department of Water Resources (DWR) Flood Emergency Response Grant, which was successfully funded by DWR.