An economic impact assessment of the use of earth observation information in flood hazard communication

Flood hazard forecasts are critical information to reduce the impacts of a disaster. Improved operational forecasts can lead to timelier decisions, which translates into more cost-effective pre-flood mitigation decisions. In this paper, we quantify this economic value of an improved forecast for two types of independent empirical adjustments to National Weather Service Ensemble Streamflow Prediction (ESP). The North Central River Forecast Center (NCRFC) adjusts the ESP to produce an operational seasonal river discharge forecast with forecaster intervention and complements the forecast with an experimental empirical soil moisture adjustment from the Gravity Recovery and Climate Experiment (GRACE). In a retrospective case study, we apply the complementary NCFRC + GRACE forecast to increase the confidence in implementing flood mitigation earlier in flood hazard planning. Specifically, we focus on the reforecast of the 2011 spring season for the Sheyenne River in North Dakota and find that flood protection decisions in Valley City, ND could have been made 5 days earlier and mitigation costs could have been reduced by $1.7 million.