Abstract
The economy, environment, and society are heavily impacted by precipitation during floods, and droughts events. Recent technological advancements in satellite-retrieved, and radar precipitation products showed better resolution and coverage that resulted to sustainable data collection. Nevertheless, uncertainty and lack of consistency in information records can portrays a weakness while incorporation retrieved estimate and operational decision making. In this paper, the goal is to evaluate. Hydrologic Modeling System (HEC-HMS) to simulate one flood event to investigate the effect of watershed subdivision. The Model utilized satellite products rainfall estimator (TRMM 3B42) and NEXRAD Stage HI in the Upper St. Johns River, located in the Mid-Eastern part of Florida. While taking into consideration extreme event in August 2008. The data were collected from 5 local precipitation gages in the St. Johns River District. Using validation metrics, this data was aggregated and differentiated between in-situ based rainfall, radar, and satellite derived rainfall. The detected rainfall amounts and volume of correctly identified precipitation, NEXRAD Stage provides a better possibility for accurate estimation and variability of precipitation at this high spatial resolution. In fact, the simulation results show less accuracy in predicting flow in the study area, but overestimation in the regions. Although comparable to radar-only simulations in terms of magnitude and time-to-peak, there is no discernible improvement in predicting these quantities.