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~, Rating curves must be established and checked periodically for each ofthe streamflow monitoring locations. A rating curve is a theoretical relationship between stream stage (measured by the sensor) and discharge. Rating curves should be checked every 6 months. In order to ensure that the data being collected is useful to other entities within the City, quality assurance and quality control (QAlQC) activities will be designed and initiated at the primary base station. Typically, the streamflow data requires the greatest effort to check and to maintain a historical record of high quality. A standard QAlQC procedure is to spend time at the end of each month checking all streamflow and precipitation data for outliers, consistency among gages, and consistency between precipitation and streamflow. The quality of this database is of utmost importance because it will be used to help design future stormwater improvements. 5. Annual Maintenance Cost: Approximately $2,500 per site. The annual operation and maintenance cost associated with the implementation of the early warning system is estimated to be $2,500 per site. In general, these costs reflect the annual maintenance associated with the precipitation and stream gages along with the time required to provide quality control of the data acquisition. .- 6. Discussion: Damages associated with flooding can best be described as direct and indirect damages. Direct damages generally relate to the loss of life and property. Property damage is relatively straightforward to estimate while estimating the damage associated with loss oflife is a more intangible issue. Indirect damages may include: (a) damages sustained by non-floodprone businesses/activities when there are physical or economic ties to floodprone businesses/activities; and (b) stress-induced injuries or sickness of flooding victims as well as their families and friends. Estimating both the direct and indirect damages is a very time-consuming. complex task with requires substantial data. To simplify the damage estimate for this application, the City focused on damages associated with loss oflife and property. These damages have not been increased to account for the indirect damages associated with flooding within the City. In a similar manner, quantification of the project benefits relies on a reduction in the loss of life and property afforded by the project. It is important to note, however, that reduction in the loss of life and property will undoubtedly reduce the indirect damages and increase the overall project benefits. Consequently, the benefits identified in this application should represent a conservatively low estimate of total benefits attributable to the implementation of the proposed project. /""' 23