This study investigates and compares several design storms for flood estimation in partially urbanized catchments. Six different design storms were considered: Euler II, alternating block method, average variability method, Huff’s curves, and uniform rainfall. Additionally, two extreme historical storms were included for comparison. A small, ungauged, partially urbanized catchment in Novigrad (Croatia) was chosen as a study area to account for the infiltration impact on the rainfall-runoff process. The performance of each design storm was assessed based on the flood modeling results, namely the water depth, water velocity, flow rate, and overall flood extent. Furthermore, several rainfall durations were considered to identify a critical scenario. The excess rainfall was computed using the Soil Conservation Service’s Curve Number method, and two-dimensional flooding simulations were performed by the HEC-RAS model. The results confirmed that the choice of the design storm and the rainfall duration has a significant impact on the flood modeling results. Overall, design storms constructed only from IDF curves overestimated flooding in comparison to historical events, whereas design storms derived from the analysis of observed temporal patterns matched or slightly underestimated the flooding results. Of the six considered design storms, the average variability method showed the closest agreement with historical storms.

So far reported unstable correlations between environmental settings and doline geometry require a revision of doline delineating methods and morphometric analyses that follows from such input data. We examine the reliability of the most accessible data sources for doline delineation, namely basic topographic maps at a scale of 1:5,000 and ortho-rectified aerial photographs (digital orthophotos) of 0.5 m resolution. Their reliability has been quantified in the Dinaric karst (Krk Island, NE Adriatic Sea). The adequacy of most commonly used morphometric parameters (viz. elongation and circularity) and their variations applied in previous studies are mathematically verified and practically tested. The simulation of an individual method behaviour performed on polygons with increasing circularity and elongation demonstrated their ranges of validity. The efficiency of a particular method was verified by the application to the real dataset of dolines. The optimal variation of an individual parameter (circularity = Pcc/Pd; elongation = ε of the best fitting ellipse) is identified and suggested for use in order to provide uniform results and increase the comparability of future morphometric analyses. Asymmetry (the distance between the centroid of doline ground plan and the centroid of the largest inscribed circle) as an additional parameter for describing doline ground plans has been developed and is proposed for further use.Key words: karst, doline delineating, morphometric analyses, measurement errors, Krk Island.Morfometrične analize vrtač – problem določanja oboda in računanja osnovnih parametrovNezanesljivost korelacij med okoljskimi dejavniki in geometrijo vrtač je spodbudila pregled do sedaj uporabljenih metod določanja oboda vrtač in primernosti morfometričnih analiz, ki sledijo iz teh podatkov. V prispevku preverjamo zanesljivost najširše dostopnih podatkovnih virov za določanje oboda vrtač, in sicer topografskih kart v merilu 1 : 5000 in ortofotov z ločljivostjo 0,5 m. Zanesljivost smo določali na primeru Dinarskega krasa (otok Krk, SV Jadransko morje). Primernost do sedaj najpogosteje uporabljenih parametrov (tj. sploščenost in krožnost) in njunih različic, ki se pojavljajo v literaturi, smo matematično preverili in preizkusili pri realnem naboru vrtač. Simulacija delovanja posamezne metode na poligonih z naraščajočo krožnostjo in sploščenostjo je pokazala njihova območja veljavnosti. Učinkovitost metod smo nato preverili še pri realnem vzorcu vrtač, pri katerem smo ugotovili, katera je najprimernejša različica posameznega parametra (krožnost = Pcc/Pd; sploščenost = ε prilegajoče elipse), in jo, da bi zagotovili večjo usklajenost in primerljivost rezultatov, predlagali za nadaljnjo rabo v prihodnjih morfometričnih analizah vrtač. Kot dodaten parameter za analizo tlorisa vrtač smo razvili in preizkusili indeks asimetrije oboda vrtač, tj.razdaljo med težiščem tlorisa vrtače in težiščem največjega včrtanega kroga.Ključne besede: kras, določanje oboda vrtač, morfometrične analize, merske napake, otok Krk.

An approach to the global estimation of water balance elements and their spatial distribution using GIS is presented. It is primarily related to the catchments where measured data are scarce and the spatial differentiation of the hydrological characteristics is not possible without climatological data. Emphasis is placed on estimating the water balance of transboundary karstic aquifers, where problems concerning the hydrometeorological data, catchment boundaries and determination of water balance elements in general are far more complex. The runoff estimation was done using the Turc and Langbein methods, which are the most frequently applied in this region. The years 1961–1990 were used as the reference period. Based on comparison of the results, the applicability of the methods is discussed. The approach proposed is suitable for estimation of water balance in the study area and may also be applied in a wider region. Résumé Une approche de l'évaluation globale des termes du bilan hydrologique et de leur distribution spatiale sous SIG est présentée. Elle concerne notamment les bassins versants où les données mesurées sont rares et où la différentiation spatiale des caractéristiques hydrologiques n'est pas possible sans données climatologiques. L'accent est mis sur l'estimation du bilan hydrologique d'aquifères karstiques transfrontaliers, où les problèmes liés aux données hydro-météorologiques, aux limites des bassins versants et à la détermination des termes du bilan sont en général beaucoup plus complexes. L'estimation de l'écoulement a été réalisée en utilisant les méthodes de Turc et de Langbein, les deux méthodes le plus souvent utilisées dans cette région. Les années 1961–1990 ont été utilisées comme période de référence. L'applicabilité des méthodes est discutée, sur la base de la comparaison des résultats. L'approche proposée est appropriée pour l'estimation du bilan hydrologique dans la zone étudiée, et peut é...