Drought characteristics addressing duration

[wjzRdam]

Dear people of the Pastas community,
Groundwater level indicators often classify the the groundwater level relative to a (historical) level history. For drought, not only the level but also the duration is important.
For the Groundwater head viewer of TNO Geological Survey of the Netherlands, we thought of quantities to give some information on the duration:

• if the current percentile is below the 25th percentile, the number of days the groundwater level already has been below 25;
• if the current percentile is below the 10th percentile, the number of days the groundwater level already has been below 10 and the number of days the groundwater level has been below 25.
  For precipitation, it is quite common to work with 'dry runs' (consecutive days without precipitation).
  Would it be useful to further think about such quantities for Pastas?
  Thank you, Willem Zaadnoordijk