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411 DWR and CWCB Flood Hardening of Existing Stream Gages Page 3 <br /> once per four hours to once per hour)transmission of data from remote sites to the central computer. This <br /> has resulted In near'real-time' data on the system. The current equipment costs of a high data rate DCP <br /> upgrade with the new GOES transceivers, antennas, batteries, gage height sensors, solar panels, wiring, and <br /> grounding equipment for a standard stilling well type gage station is just under$5000. It is projected that the <br /> entire DWR SMS system will be upgraded to high data rate by the end of FY2009-10. Beyond that point in <br /> time, requests to CWCB for the SMS satellite telemetry equipment will be of a maintenance nature rather <br /> than complete upgrades. <br /> Refurbishment of Existing Stream Gages <br /> DWR requests$55,000 for refurbishing existing stream gages in FY2009-10. Approximately 60%of <br /> Colorado's satellite-linked gaging stations are located in the rivers and streams of the state. The others are <br /> located in reservoirs, ditches, and canals. The electronic equipment is attached to mechanical equipment in <br /> and along the stream channel, and electronically relays the data sensed by the mechanical measuring <br /> devices. If the mechanical equipment and associated stream gage structures(shelters, stream controls, <br /> independent reference gages, etc.)are not properly maintained and periodically refurbished, data quality and <br /> accuracy diminishes. <br /> Flood Hardening/High Flow Measurement Sustainability at Existing Stream Gages <br /> DWR and CWCB jointly request$50,000 for continued flood hardening of existing stream gages and <br /> enhanced high flow measurement capacity in FY2009-10. <br /> In 2001, a committee of representatives of DWR, CWCB and the USGS evaluated and ranked, <br /> • using a set of flood warning/monitoring criteria, all satellite monitoring stream gages throughout the <br /> State. This ranking has identified prioritized sites where flood-hardening projects would be useful in <br /> flood warning and notification. The cost to modify many of these gages to withstand flood events <br /> varies considerably. Each site is being evaluated for required modifications to flood harden the <br /> gage. Flood hardening, by definition, allows for stream flow data to continue to be transmitted during a <br /> flood event. Flood hardening prevents the need to develop a plan to remove all equipment from stream <br /> gages prior to their destruction by floods. While this equipment removal saves equipment costs, this <br /> does not allow for data transmission during flood events to emergency managers and the public. Flood <br /> hardening involves moving or modifying the existing stream gages so that they can continue to operate <br /> during flood events. In some cases, it may be necessary to add a second gage at the site on higher <br /> ground so that the low flows needed for accurate water administration can be measured and the high <br /> flows of floods also can be measured. Another form of flood hardening involves rebuilding the stream <br /> channel so that accurate data will continue to be available during the flood. Often the stream channel <br /> becomes scoured or modified to the point that existing relationships between stage and discharge are no <br /> longer valid at high flow. Even if the stage data continues to be available, it is of little or no value in <br /> determining the flow of the river. <br /> High flow measurement capability varies from gage to gage. High flow discharge measurements at DWR <br /> stream gages are important for maintaining/updating the high flow portion of the stage-discharge <br /> relationship for the gage. This calibration consequently improves the accuracy of high flows reported at <br /> the gage(s). High flows at stream gages are measured from cableways at the gage or from nearby up-or <br /> downstream bridges. Cableways at DWR stream gages are given a detailed inspection each four years. <br /> During the past 4 years many cableways, primarily because of age, have been found to need <br /> replacement of key components of the cableway system. High flow measurement sustainability projects <br /> address such identified cableway design/safe use issues. These may include replacement of cable, <br /> improvements to the cable anchorage system, replacement of A-frame components, replacement of <br /> cable cars, etc. Alternatively, existing cableways found to have design or safe use deficiencies are, <br /> • under certain site conditions, being replaced with bank-operated cableways. High flow measurements <br /> are facilitated with new technology measuring equipment:Acoustic Doppler Current Profilers(ADCPs). <br />