Probable Maximum Precipitation, Annual Exceedance Probability, and Climate Change Analysis for TransAlta projects.
Project Scope
PMP, AEP, and climate change assessments were developed for all projects within the TransAlta portfolio. This included many areas affected by extreme topography and high spatial variability of rainfall and snow accumulation patterns. In addition, many areas of the mountainous regions had limited data. Therefore, AWA had to utilize our unique expertise to overcome these challenges. This included a combination of data from observation information, gridded reanalysis products, HRRR model outputs, and remotely sensed data. Results of this analysis reflect the current standard of practice used for defining PMP, including comprehensive storm analyses procedures, extensive use of geographic information systems (GIS), explicit quantification of orographic effects, and storm specific temporal patterns, and improved understanding of the weather and climate related to extreme throughout the region.
The new PMP estimates are available from a single grid point to the entire region covering all TransAlta watersheds. Our updated PMP depths capture the extreme variations in precipitation depths that encountered across the region and better quantify rain vs snow accumulations. This provides the required outputs for proper hydrologic modelling over this complex system. The development of the AEP over the same gridded domain provided critical information and sensitivity analysis to ensure PMP depths are reasonable and as input for risk informed decision processes.
