{'fraction_non_alphanumeric': 0.016763378465506126, 'fraction_numerical': 0.0, 'mean_word_length': 5.386831275720165, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
REGIONALIZATION METHODS FOR LOW FLOW ESTIMATION IN UNGAUGED CATCHMENTS – A REVIEW

Aim of the study The purpose of the paper is to look at the topic of estimation of the low flow characteristics at ungauged catchments in a balanced and systematic way, to provide a recent documentation of the subject and trace the most recent trends in low flow regionalization. The review focuses on methods, which are based on diverse methods that is the statistical, seasonal approach which are commonly used for the estimation of low flow characteristics in ungauged sites and which can be adopted in Polish conditions. Material and methods The paper examines the variety of literature sources published primarily during the last two decades. The most popular approaches to regionalization of watersheds are described: methods of residuals pattern approach, multivariate statistics such as cluster analysis, Classification and Regression Tree (CART) models or seasonality of low flows. Results and conclusions The described regional regression approach for low flow estimation in ungauged catchments, which correlates low flow indices and catchment characteristics, is the most widely used method. The methods were chosen because they differ in terms of methodological approach to using statistical methods. Also, the methods described in the article are “universal”, which means that they can be adopted for different regions, countries, including Poland; they are interdisciplinary, and can be adopted for low flow calculation as well as average or flood flows.