POT Peak Over Threshold

I have a very large dataset recording measurements everyday for a substantial amount of time. I want to code multiple POT's for this data set. I have the known thresholds; however, I am not sure how to code this?

[Image Analyst]

What does it do? To find the data above a threshold you can do this

indexes = data > threshold;

What more than that do you need?

[Dale Andrew]

Its to find the highest peaks (flooding events) from river flow data. For example, using a threshold that finds the top 50 peaks (floods) from the given time series. Then once this is identified, trying to distinguish these peaks as independent events.