Questions on lake.csv

[JJJ2021]

Hi GLM community, does anyone know what does the Lake Number mean? How was it calculated? I have a scenario and shown all Lake Number column as 0, no variations in Max Temp, Min Temp and Surface Temp. Also Max dT/dx column shows "nan" under a 10-year simulation setting. If I run a 60-year simulation, more lake.csv cells show "nan". The results of these scenarios look weird. With the same input files (flows rate and climatic input), the results for the 1st reporting day given by the lake.csv also look inconsistent between these two scenarios (10-year and 60-year). Thank you.