Testing the Drought and Heat Risk (DHR) Assessment Framework for Urban Green Infrastructure: Drought Return Period

Drought Return Period

The plant available water (PAW) was extracted from the DWD Station 3946 for the town of Plauen, Germany for the years 1991-2022. This data was processed to analyze the frequency of drought events for a given intensity level, as part of a doctoral dissertation on the drought and heat risk assessment for urban green infrastructure and their ecosystem services. The average PAW was calculated for the depth of 0-60 cm using: BF10, 20, 30, 40, 50, 60. The percentiles were calculated to identify the return period corresponding to the PAW value used in the ENVI-met model (36.6%). This return period and selected intensity represent the parameters of the drought hazard for Plauen, Germany.

Percentiles 0.2, 0.1, and 0.05 were used to define moderate, severe, and extreme droughts respectively.

Return period for a monthly percentile (August): PAW=36.6% –> 1 to 20 years

Return period for absolute percentile: PAW=36.6% à 1 to 70 months à 1 to 5.84 years (USED in ENVI-met)

Return period for absolute percentile: PAW=46.04% à 1 to 19 months à 1 to 1.59 years (USED for correlation indicator)

Note that %PAW (or %nFK) could be converted into % Soil Moisture (SM) using the formula:

%SM= ((FC –WP) x %nFK )+ WP

Where WP: Wilting Point; FC: Field Capacity; %nFK: % of plant available water capacity

For sandy loam: FC=37% and WP=13%

Data sources and overview:

Shehayeb, R. (2025). Testing the Drought and Heat Risk (DHR) Assessment Framework for Urban Green Infrastructure: Overview and Data Sources. Zenodo. https://doi.org/10.5281/zenodo.14719567