Invalid Range Value After Fill Analysis Process Using DTM

[HakimiImran]

Hello Esri Communities!

I recently got a project which requires me to calculate the catchment area. To do that, I firstly need to do the 'Fill' spatial analysis to eliminate the depression. But, after the process, I got a weird value range. From what I understand, the post-processed of fill value supposedly should not be so different with pre-processed file (which is the DTM). I couldn't figure out the reason. Can someone enlighten me with this problem?

(I inserted below image for better understanding. The top one is post fill processed file and the bottom one is pre-processed file)