A Real-time Flood Monitoring Index Based on Daily Effective Precipitation and its Application to Brisbane and Lockyer Valley Flood Events

• Published in: Water resources management 2015-09, Vol.29 (11), p.4075-4093
• Main Authors: Deo, Ravinesh C, Byun, Hi-Ryong, Adamowski, Jan F, Kim, Do-Woo
• Format: Article
• Language: English
• Subjects: Atmospheric Sciences; Civil Engineering; Drought; Early warning systems; Earth and Environmental Science; Earth Sciences; Effective precipitation; Emergency communications systems; Environment; Environmental monitoring; Environmental risk; Environmental science; Flood control; Floods; Freshwater; Geotechnical Engineering & Applied Earth Sciences; Hydrogeology; Hydrology; Hydrology/Water Resources; Mathematical analysis; Monitoring; Precipitation; Rain; Real time; Resource depletion; Risk assessment; Standard deviation; Studies; Valleys; Warning systems; Water resources; Water resources management
• ISSN: 0920-4741; 1573-1650
• DOI: 10.1007/s11269-015-1046-3

An objective index for flood monitoring is pragmatic tool for flood early warning systems. This study investigates a novel Flood Index ( I F ) based on Effective Precipitation ( P E ) for quantifying floods in Brisbane and Lockyer Valley. Using daily precipitation ( P ) data as an input, the I F was determined by calculating P E using exponentially-decaying time-reduction function considering gradual depletion of water resources over the passage of time and comparing and normalizing the P E per day with the means and standard deviations of yearly maximums in the hydrological period. Start of flood was identified for I F ≥0, severity ( I F acc ) assessed by running-sum on consecutively positive I F , duration ( D F ) as number of days with positive I F and peak danger ( I F max ) as maximum I F . The ability of I F for flood warning was verified with river height and discharge rates. The most severe flood was recoded in January 1974 in Brisbane ( I F acc =118, I F max =4.4, D F  = 104 days) with return period ( T ) =106.2 years. Next was the December 2010–January 2011 event ( I F acc =61.8 , I F max =2.6, D F  = 89 days) with T  = 53 years. For Lockyer Valley, December 2010–January 2011 was the most severe ( T  = 104.4 years). Consequently, we advocate the practicality of the daily I F for flood risk assessments where severity, peak danger, duration or return periods are to be considered.