Rise and Fall Method – Surveying (RL Calculation) The Rise and Fall Method is used in leveling to determine the Reduced Levels (RLs) of points by comparing consecutive staff readings. Steps of Calculation 1. Take staff readings as BS, IS, and FS. 2. Compare consecutive readings to find Rise or Fall. 3. If next reading is smaller → Rise. 4. If next reading is larger → Fall. 5. Calculate RL using previous RL. Formula Rise = Previous Reading − Next Reading (if positive) Fall = Next Reading − Previo