Criteria for identifying maximum rainfall determined by the peaks-over-threshold (POT) method under the Polish Atlas of Rainfall Intensities (PANDa) project

Abstract

Abstract. Determination of rainfall maxima from long-term series is one of the more important tasks in urban hydrology. These maxima are useful both in designing land drainage systems and for flood protection in a catchment.The identification of rainfall maxima for the hierarchy of rainfall durations from 5 min to 4 320 min is a fundamental stage of the creation of the first version of the Polish Atlas of Rainfall Intensities (PANDa), which will ultimately be a source of updated and reliable information on design rainfall intensities for designing and modeling rainwater drainage and retention systems in Poland. One of the methods for identifying extreme rainfall events is to use criteria for selecting rainfall based on their depth for a given rainfall frequency and duration. Existing national experience in this respect is based on the results of analyses usually conducted with regard to records from single weather stations. This article presents the results of a study designed to verify the usefulness of the literature-based criteria for identifying rainfall maxima using the peaks-over-threshold (POT) method at a much broader nationwide scale.The study analyzed data from a previously created digital database of rainfall series, which includes 3 000 stationyears (consisting of a 30-year measurement series from 100 weather stations of the Institute of Meteorology and the Water Management -National Research Institute (IMGW-PIB). The study results show that as far as the investigated measurement series are concerned, the criteria based on the literature sources have limited application and can only be used for identifying the largest short-duration rainfall events. To determine rainfall maxima for all of the time intervals analyzed (from 5 minutes to 3 days), it was necessary to develop our own criteria that would allow the methodology for identifying extreme rainfall events to be standardized for all 100 stations.

Stormwater Reservoir Sizing in Respect of Uncertainty

“…in which ξ-regional parameter differentiating the variability of the obtained curves, J-mean rain intensity in dm 3 •(ha•s) −1 , expressed as J = 166.7•P max . Due to a number of conditions, such as the genesis of rainfall, climatic conditions, land use, the length of rainfall measurements, etc., the relationships described by Equation (1) may take different forms [20,33,34]. Taking into account the above remarks and the climate conditions in Poland, which was reflected in a series of works [20,35] aimed at developing empirical rainfall models, the formula of Bogdanowicz and Stachy [32] was used in the analyses to determine the maximum rainfall depth (P max ) for the assumed precipitation frequency:…”

“…In practical studies, usually there is a lack of observed time series. The design rainfall can be determined using regional precipitation models, which on the basis of empirical relationships allows for estimation of its height for the given duration and occurrence frequency [20,21]. The approach takes a form of so-called Intensity-Duration-Frequency (IDF) curves and can be also used for a rainfall generator.…”

The separation of maximum amounts of precipitation for the Polish Atlas of Rains Intensities (PANDa)

“…This database, covering the years 1986-2015, consists of digitized pluviographic paper strips records (mostly rainfall data from 1986 do 2005) and registration from electronic rain gauges available from 2000 to 2015 (RG-50 SEBA working at synoptic stations and Met One Instruments 60030 -unheated and 60030H -heated, working at lower-graded IMWM-NRI stations). Rainfall data comes from a network of 100 rain gauges of the national hydrological and meteorological service, whose location is shown in Figure 1 [13].…”

“…Therefore, Poland, using these experiences has a chance to create a tool for the 21st century [9][10][11][12]. Polish Company Retencjapl in cooperation with the Institute of Meteorology and Water Management -National Research Institute, applied to the National Center for Research and Development with a request for co-financing of the project entitled: Development and implementation of the Polish Atlas of Rains Intensities (PANDa) -the Smart Growth Operational Programme 2014-2020 POIR.01.01.01-00-1428/15 [13]. This article describes one of the stages of the project, which consists in separating the maximum rainfall amounts from the previously prepared (majorly digitalized from archival meteorological paper reports) rainfall time series as a partial duration series (PDS) of 16 durations from t1 = 5 to t16 = 4320 min.…”

“…Preparation of such an accurate numerical database of pluviographs allowed in subsequent stages to develop reliable rainfall models, which in the final stage will enable to construct a long-awaited atlas of intensive rainfall in Poland in the form of IDF and DDF dependencies. Moreover uniformly methodically developed rainfall database covering the whole country will allow to supplement the lack of knowledge about intensive rainfall in the area of interdisciplinary activities of science, climate change and civil engineering [13].…”