Channel-reach morphometric analysis on a headwater stream in a low-mountainous region: A case study from Mecsek Hills 365Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381.DOI: 10.15201/hungeobull.72.4.3 Hungarian Geographical Bulletin 72 2023 (4) 365–381. Introduction An important aspect of fluvial landscape evo- lution research involves streams and their channel characterisation from various per- spectives. This topic is widespread and has an extensive global scientific literature, dating back to the late 19th century and continuing to the present day, evidenced by the numer- ous papers published on the description and systematic classification of streams (Leopold, L.B. and Markley, G.W. 1957; Kaszowski, L. and Krzemien, K. 1999; Lóczy, D. 2012; Buffington, J.M. and Montgomery, D.R. 2013; Bisson, P.A. et al. 2017, and references therein). The streams and their immediate envi- ronment (floodplains and valleys) are often described by their hydrogeomorphological characteristics. In addition, essential param- eters can be derived from the geological, hydrological, land cover, land use, and eco- logical features of the catchment (Rosgen, D.L. 1994; Fryirs, K.A. and Brierley, G.J. 2001; Fryirs, K.A. et al. 2007; Gurnell, A.M. and Grabowski, R.C. 2016; Grabowski, R.C. et al. 2019, and references therein). At present, anthropogenic influences such as flood control measures, channelisation, and forestry are in- creasing in frequency and intensity. The liter- ature overview demonstrates the lack of a uni- 1 Doctoral School of Earth Sciences, Institute of Geography and Earth Sciences, University of Pécs, Pécs, Hungary. Ifjúság útja 6. H-7624 Pécs, Hungary. E-mail: vbalazs90@hotmail.com 2 Institute of Geography and Earth Sciences, University of Pécs, Pécs, Hungary. Ifjúság útja 6. H-7624 Pécs, Hungary. E-mails: gazi@gamma.ttk.pte.hu, loczyd@gamma.ttk.pte.hu, nagyvarl@gamma.ttk.pte.hu, smafu@gamma.ttk.pte.hu 3 Doctoral School of Earth Sciences, Institute of Geography and Earth Sciences, University of Pécs, Pécs, Hungary. Ifjúság útja 6. H-7624 Pécs, Hungary. E-mail: brichard@gamma.ttk.pte.hu Channel-reach morphometric analysis on a headwater stream in a low-mountainous region: A case study from Mecsek Hills Balázs VÍG1, Gábor VARGA 2, Richárd BALOGH3, Dénes LÓCZY2, László NAGYVÁRADI 2 and Szabolcs Ákos FÁBIÁN2 Abstract Small catchments in mountainous regions affect downstream rivers as a primary source of sediment supply and also generate flash swasfloods, especially during extreme events. These floods have significantly shaped the catchments of small streams in the Mecsek Hills and some rural areas over the past two decades. However, there has been no previous study examining the hydromorphology of headwater catchments in low mountain environments in Hungary. The present study was meant to investigate the fundamental hydrogeomorphologi- cal properties of a first-order catchment. A customary and detailed GIS survey of 50-metre sections was aimed at deciphering flash flood vulnerability and geomorphic interrelations within a micro-watershed. We found moderate susceptibility to flash floods compared to the whole Mecsek Hills. Stable large woody debris jams were identified during the field survey as major geomorphic channel features functioning as natural barriers which drive channel evolution and reduce flood hazards. Keywords: hydromorphometry, large woody debris, semi-natural, stream reach, field survey, Öreg-patak stream file:///C:\Users\vbala\OneDrive\Carpatho%20cikk\Natural%20hazards%20Original\vbalazs90@hotmail.com mailto:gazi@gamma.ttk.pte.hu mailto:loczyd@gamma.ttk.pte.hu mailto:nagyvarl@gamma.ttk.pte.hu mailto:smafu@gamma.ttk.pte.hu mailto:brichard@gamma.ttk.pte.hu Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381.366 versal classification system valid across all geo- graphical locations. Nonetheless, the available classification techniques enable the adoption of a suitable survey approach that considers all the relevant attributes of the area under study. The hierarchical classification system is well suited to streams with various features. A clear advantage is that the units within a given catchment are split along the scale into small- er and more interpretable segments. These units, such as valley segment (100–10,000 m), stream reach (10–1,000 m), and channel unit (1–10 m) make the investigations of headwater streams possible. Thus, even for small streams, as well as larger rivers, qualitative and quan- titative parameters can be assessed both along the longitudinal profile and at cross-sections (Płaczkowska, E. 2016; Bisson, P.A. et al. 2017). The longitudinal profile allows differentiation of segments according to stream power, incision rate, accumulation zones, and sediment load in terms of quantity, composition, and particle size (Buffington, J.M. and Montgomery, D.R. 2013). The sections offer key information on changes in channel shape and sinuosity (such as straight, meandering, and braided). These processes sig- nificantly affect cross-section parameters (for example, bankfull width and/or depth, channel shape index) and channel forms (including cut- banks, steps, alluvial bars, potholes, riffles, and pools) (Kamykowska, M. et al. 1999). Organic material accumulation also signifi- cantly affects bed morphology. This effect is especially noticeable in headwater areas cov- ered by mountain forests, where organic matter is abundant, ranging from tiny seeds, leaves, twigs (Jeffries, R. et al. 2003) to branches and woody debris of much larger size (Galia, T. et al. 2018; Thompson, M.S.A. et al. 2018). Its im- pact on the channel and processes is diversified and complex. Woody debris accumulation can transform the flow conditions and thalweg of the channel. Therefore, it cannot be neglected in bank evolution either since it can accelerate streambank erosion or protect streambanks (Bilby, R.E. and Ward, J.W. 1991; Abbe, T.B. and Montgomery, D.R. 2003; Comiti, F. et al. 2006; Ruiz Villanueva, V. et al. 2014; Short, L.E. et al. 2015; Wohl, E. et al. 2017, and refer- ences therein). It is important to note that the organic materials in channels also contribute to trapping sediment. This can have spectacular consequences in the formation of impound- ments and steps in the channel, whereby the morphological conditions and processes can change (e.g., erosion potholes can be created) (Galia, T. et al. 2017; Zhang, N. et al. 2020). Furthermore, these accumulations promote the precipitation of travertine, which can en- hance the stability of natural dams (Carter, C.D. and Marks, J.C. 2007; Compson, Z.G. et al. 2009; Fuller, B. et al. 2011). A comprehensive understanding of their features can be achieved through examin- ing the aforementioned forms, factors and impacts along the longitudinal profile of streams. The distinction between segments is aided by the detailed field survey pro- tocols developed for this purpose (Myers, T.J. and Swanson, S. 1997; Kamykowska, M. et al. 1999; Galia, T. et al. 2018). Numerous stud- ies using a similar approach have been com- pleted over the last decade, but typically con- ducted in high and mid-mountain watersheds and streams (Galia, T. and Hradecký, J. 2011; Galia, T. and Škarpich, V. 2013; Płaczkowska, E. et al. 2015; Płaczkowska, E. and Krzemień, K. 2018; Ondráčková, L. and Máčka, Z. 2019; Prokop, P. et al. 2020). Nonetheless, many field methods can be adapted for small watercourses with low- er relief, even in hilly regions. Comparable studies have already been carried out in Hungary (Kalmár, P. et al. 2013; Fábián, Sz.Á. et al. 2016), but they are few in number at the national level. The objective of this paper was twofold. Firstly, it aimed to describe and analyse the trunk channel of the micro-catchment for bed types, shapes, and evolution, based on a com- prehensive field survey. Particular emphasis was placed on the formation and evolution of natural log jams affecting sediment transport. Secondly, it was meant to estimate the flash flood susceptibility (FFS) value for the select- ed micro-catchment since flash floods have in- creased in frequency in Hungary due to recent extreme weather events. 367Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381. Study area This study focused on the southern branch of the Öreg-patak (Öreg Stream) Mecsekná- dasd, which originates from a spring in eastern Mecsek. It runs in a north-easterly direction for just over seven and a half kilometres, where it joins the Puszta-árok (Óbányai-patak) between the villages Mecseknádasd and Óbánya. The studied watercourse and its associated per- manent and ephemeral streams have a catch- ment area of 9.75 km2, which just falls into the micro-watershed category (Daipan, B.P.O. 2020). The highest point of the catchment is the Zengő (682 m), the lowest near the conflu- ence is at 224 m (Figure 1). Relative relief ranges from 123 to 247 m/km2. Although the studied stream may be considered relatively natural, intensive forest management by the Mecsek- erdő Zrt. (Mecsek Forestry Co. Ltd.) and the popularity of the marked hiking trails indicate significant anthropogenic impact. Sedimentary rocks dominate the geologi- cal setting. The Lower Jurassic Pliensbachian and Toarcian beds of limestone, chalk marl and siltstone (Óbánya Aleurolite Formation), locally intercalated by Lower Cretaceous (Valanginian) alkaline basalts (Mecsekjános Basalt Formation), are the most widespread formations. They are mostly covered by young Quaternary sediments, including slope deposits, loess, and its derivates. Sporadically, sedimentary and sub-volcanic rocks are exposed (Raucsik, B. and Varga, A. 2008; Haas, J. 2013). The studied catchment and its immediate surroundings display the characteristic sub- dued, denuded shape of the Eastern Mecsek Fig. 1. Map of the study area. Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381.368 region. Main features of the topography are the radially spreading horsts and connecting ridges on which the boundary of the watershed (di- vide) runs. The valley shoulders are described in several places in the valleys and the higher hilly surfaces are dissected by erosional-dera- sional valleys (Ádám, L. et al. 1981; Kocsis, K. 2018). Slope angles range from 0 to 35 degrees. The majority of the study area is represented by the range from 7 to 25 degrees (mean 15.47; Std. dev. 6.24; 8.31 km2; 85.2%) (Figure 2). The climate is notably influenced by the north-northeast orientation of the catchment and its main valley. Mean annual air tem- peratures (MAAT) vary between 7 and 9 °C; mean annual precipitation (MAP) totals are 750–850 mm. However, in certain years the MAP reaches very extreme values, for exam- ple, in exceptionally wet 2010 and 2014 years and in the arid year 2011 (Czigány, Sz. et al. 2010; Hungarian Meteorological Service, n.d.). The Öreg-patak (second-order stream at the mouth) and a few short, perennial and ephem- eral streams are all part of the Danube water system, reaching the Danube via the Völgységi- patak (Völgységi Stream) and the Sió canal (Kocsis, K. 2018). The length of streams which are considered permanent is 9.9 km. The watershed is almost entirely covered with forests managed by the Mecsekerdő Zrt. The vast majority of tree species are European beech (Fagus sylvatica), sessile oak (Quercus patraea), Turkey oak (Quercus cerris), downy oak (Quercus pubescens) and hornbeam (Carpinus betulus), which are often mixed. Indeed, in more limited spots in the upper reaches of the main streams, planted spruce (Picea abies) is also found (Kevey B. 2008). The closed forests are only occasion- ally dissected by small clearings or seedling orchards, and more significantly, by gaps be- tween forest stands (data from Mecsekerdő Fig. 2. Slope map of the study area with its border line (A) 369Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381. Zrt. and Ministry of Agriculture, 2019). Highly acidic Luvisols and Alisols predom- inate with only small patches of Regosols (Kocsis, K. 2018). The study area covers parts of the ad- ministrative areas of five settlements (Hosszúhetény, Mecseknádasd, Óbánya, Pécsvárad and Zengővárkony). However, only a minute portion of inhabited land is affected, near the mouth of the Óbányai- patak stream (Mecseknádasd Resort Area). Human activities significantly affected the morphology of the riverbed in these areas and near the forest tracks and logging sta- tions of permanent use. Materials and methods For the present study, two methodological procedures were applied. Firstly, 25 catch- ment parameters (e.g., area, perimeter, drain- age density, Gravelius coefficient, number of streams, total stream length, max stream order, max and min height, basin relief, for- ested area) derived from a hydrologically correct digital elevation model (DEM) with 10 m resolution were identified (Schumm, S.A. 1956; Strahler, A.N. 1957; Sasso- las-Serrayet, T. et al. 2018; Daipan, B.P.O. 2020; Víg, B. et al. 2022). For detailed GIS analyses, we also applied the South-Trans- danubian Water Management Directorate (STWMD) vector surface water database, the Corine Land Cover 2012 (CLC2012) dataset, the closed sources forestry data of Mecsek Forestry Company (MF), and the ecosystem map of Hungary by Ministry of Agriculture (2019). For the spatial analyses, we used ArcGIS 10.4 (ESRI, 2016) and open-source ArcHydro Toolbox v2.0 (ESRI, 2011). Relying on previous FFS studies (Esper Angillieri, M.Y. 2008; Singh, P. et al. 2013; Abdel-Fattah, M. et al. 2017; Puno, G.R. and Puno, R.C.C. 2019; Alam, A. et al. 2020; Obeidat, M. et al. 2021), the following mor- phometric parameters had been selected for examination: area (A), drainage texture (Rt), drainage density (Dd), elongation ratio (Re), form factor (Ff), lemniscate index (k), Gravelius coefficient (GC), forested area (Fa), relief ratio (Rr). Among them, A, Dd and Rr were assumed as directly related to the prob- ability of flash flood generation, while Rt, Re, Fa, Ff, k, and GC were inversely related to flash floods. All selected factors are related to runoff intensity and flash flood generation; therefore, they could be applied, using the approach of Víg, B. et al. (2022), for assessing FFS at the watershed level. Thus, the current- ly studied watershed parameters were com- pared with previously published data for the Mecsek Hills region. Secondly, a comprehensive field survey was conducted to record in detail geolo- gy, bed morphometry, geomorphology and land cover of the Öreg-patak catchment. The field survey was essentially carried out following the paper of Kamykowska, M. et al. (1999), from the source to the mouth, over a length of more than 7,700 m, divided into 155 fifty-metre-long sections. The protocol developed in Polish Carpathian Mountains was applied to low-mountainous environ- ments and low-discharge streams (Kalmár, P. et al. 2013; Kalmár, P. 2015; Fábián, Sz.Á. et al. 2016). About four-fifths of the original proto- col has been used, supplemented by measur- ing woody debris jams (WDJ) in the channel, which strongly influence hydromorpholog- ical features (Bilby, R.E. and Likens, G.E. 1980; Dahlström, N. and Nilsson, C. 2004; Galia, T. and Hradecky, J. 2014). Following the original protocol’s logic, the WDJ param- eters survey was structured to collect the data detailed below. We used a laser rangefinder (Hecht 2006 laser distance meter) to record the relative position of the WDJ in the channel and their basic physical parameters including the pre- dominant and maximum height, width, and length. Furthermore, the WDJ’s orientation to the flow direction and the effect of organic matter (such as leaf litter, green leaves, senes- cent leaves, and small wood fragments) accu- mulation in the channel was also recorded, as they can influence flow conditions inde- pendently of log jams (Přibyla, Z. et al. 2016). Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381.370 Using a portable GPS device (Garmin 60 CSx), we recorded all the features (includ- ing bedrock steps, anthropogenic elements, and WDJ) that impact the hydromorpholog- ical processes in the riverbed according to the HD72/EOV reference system (EPSG:23700). In addition, springs, tributaries, and even short ephemeral or perennial watercourses were surveyed to augment our primary database. Mean stream gradient was measured using a digital level (SOKKIA SDL50). The limit- ing factor was the dense vegetation in the incised stream bed and the steep valley side. Sinuosity was calculated as a ratio between the unit (50 m) curvilinear length of the channel centreline and the straight distance of each unit endpoint. Data could not be ob- tained in 67 out of the 155 surveyed sections, mainly in the upstream segment with a steep slope and incision. There was also sporadic data loss downstream due to dense vegeta- tion hindering the survey even in winter. The extent of the bedrock outcrop (estimat- ed proportion) was recorded in the surveyed sections. The rock types identified in the field were checked with the help of the detailed geological maps (scale 1:10,000) available for the Mecsek Hills area. The genetic types of any riverbed sediments and their grain size categories were also documented. Cross-sections and longitudinal profiles were classified according to the protocol categories (Kamykowska, M. et al. 1999) by channel section. Where applicable, qualita- tive data were recoded (e.g., cross sections of channel types). Among the quantitative characteristics, we measured the channel gradient (∑m/50m), the bank height and the total bankfull depth and width. These mea- surements yielded the channel shape index (bankfull width/maximum bankfull depth) for each channel section. We collected over 2,000 data points, which were then recorded in a Microsoft Excel spreadsheet, also used to perform the necessary statistical analysis to interpret and evaluate data. Eleven cam- paigns were conducted between March 2019 and May 2020, primarily during low water stages. Results and discussion Watershed morphometric analysis and flash flood susceptibility A complex hydrological, relief and land use analysis of the Öreg-patak catchment pro- vided valuable information on the FFS of the region. The relatively small area and the associated maximum catchment basin length (L) imply a high flash flood sensitivity due to the low accumulation time. However, this is offset by low (≤ 2) drainage texture and drainage density, which decreases the like- lihood of flash floods occurrence. Among the areal parameters, low (highly elongated, ≤ 0.5, or elongated, 0.5–0.7) values of elon- gation ratio, form factor and circularity ratio also reduce FFS due to the highly elongated shape. High values of the Lemniscate index and Gravelius coefficient, as well as the high degree of forest cover, were also interpreted as moderating effects on the studied catch- ment. Comparing the presented values in this paper with the former general FFS anal- ysis of the Mecsek region by Sarkadi, N. et al. (2022), and Víg, B. et al. (2022), FFS in the catchment was estimated to be moderate or medium. Based on the flash flood events observed in the past decade, mud and woody debris ‘floods’ can only be caused by extreme precipitation at the confluence of headwater branches (Table 1, Photo 1). Channel reach analysis The field survey was carried out on 155 channel sections with a length of 50 m from the source of the southern headwater of the Öreg-patak to the mouth of the watercourse. Of these, 30 sections are located upstream the confluence of the three headwaters. Early Jurassic (Pliensbachian and Toarcian) sediments dominate the examined sections (n = 144). Further eleven sections overlie thin alkali basalt, trachybasalt, and phono- lite dykes of Early Cretaceous (Valanginian) age. We estimated the percentage of bedrock 371Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381. Photo 1. Woody debris ‘flood’ after an extreme precipitation event at the end of May, 2019. (Photo taken by Attila Szalay, Mecsek Forestry Co. Ltd, 2019). Table 1. Fundamental morphometric parameters of the studied catchment with the highlighted FFS relevant data Parameters Formula Value References FFS parameters Area (A), km2 Max. basin length (L), km Drainage texture (Rt) Drainage density (Dd), km/km2 Elongation ratio (Re) Form factor (Ff) Circularity ratio (Rc) Lemniscate index (k) Gravelius coefficient (GC) Forested area (Fa), % – – Rt = Nu/P Dd = ∑L/A Re = D Ff = A/L2 Rc = 4πA/P2 k = L2π/4A GC = P/2√πA – 9.75 6.80 0.31 1.01 0.52 0.21 0.24 3.69 2.03 100.00 – Kamykowska, M. et al. 1999 Horton, R.E. 1945 Strahler, A.N. 1957 Schumm, S.A. 1956 Mesa, L.M. 2006 Mesa, L.M. 2006 Moores, E.A. 1966 Sassolas-Serrayet, T. et al. 2018 Kamykowska, M. et al. 1999 Traditional further parameters Perimeter (P), km Fitness ratio (Rf) Number of streams (Nu) Integration index (C), km2/km Total stream length (ΣL), km Max stream order (u max) Total length of stream order (∑u), km Mean stream length (Lu), km Length of main channel (Cl), km Maximum height (H), m Minimum height (h), m Basin relief (r), m Relief ratio (Rr) Grassland area (Ga), % Arable land area (Aa), % – Rf = Cl/P – C = A/L – – – Lu = SL/Nu – – – r = H – h Rr = H – h-L – – 22.5 0.29 7 1.40 9.90 2 4.44 (u1); 5.46 (u2) 1.40 6.50 680 224 456 67.28 0 0 – Pareta, K. and Pareta, U. 2011 – Kamykowska, M. et al. 1999 – Morisawa, M.E. 1962 – Biswas, S.S. 2016 – – – – Schumm, S.A. 1956 Kamykowska, M. et al. 1999 Kamykowska, M. et al. 1999 Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381.372 outcrops exposed in each section and classi- fied the sections into four categories. Some bedrock was found in 58 percent (n = 90) of the surveyed sections. The lowest proportion of bedrock (< 10%) was found in 66 sections. It was measured between 10–50 percent in 21 sections, and the highest outcrop rate was between 50–90 percent in only three sections. In the remaining 65 sections (42% of the total surveyed), no bedrock could be detected. No definite pattern or regularity of the bedrock distribution can be discerned along the lon- gitudinal profile. However, rocks could be traced in all sections from 39 to 59, and from 67 to 90. Furthermore, the 10 to 50 percent occurrence was dominant in sections from 86 to 94 (n = 7). In all the sections where volcanic or subvolcanic rocks were present, bedrock also occurred in the stream bed. In addition, the 11 sections mentioned above alternated between the 10–50 percent, and 50–90 percent categories. A decrease in rock occurrence was observed downstream sec- tion 100, justified by the thickness and ac- cumulation of younger cover sediments. The low proportion of the bedrock outcrops (only 24 sections have >10% outcrop ratio) is typical of the low-mountain region in the Pannonian Basin (i.e., low altitude, relief, channel gradient, water discharge and bed- load transport intensity, and high portion of alluvial fans) (Mezősi, G. 2015; Kocsis, K. 2018). Furthermore, this feature is rein- forced by the laws governing catchments and stream channel conditions (i.e., low gradient, stream power, sinuosity), which inhibit the evolution of bedrock and colluvial channels (Bisson, P.A. et al. 2017). Slope (waste mantle) and alluvial sedi- ments could be observed in channel depos- its for most of the sections (n = 151; 91%). In the remaining minority of sections (n = 4), the same could be assumed but could not be assessed adequately due to thick leaf litter cover. Sediment grain size showed slight variation. The upstream sections (5–15) were characterised by clay and silt, while the re- maining sections contained all grain sizes from clay (< 0.004 mm) to small boulders (> 256 mm) in varying amounts. Similar sedi- ment size distributions have been reported in the streambed for small headwater streams (Galia, T. et al. 2015). Estimating the num- ber of different grain sizes over such a long reach would be difficult, imprecise, and im- possible in the field. According to Russel, R.J. (1954) and Charlton, R. (2008), alluvial channels can contain a mixture of grain sizes from boulders to clay. The variable grain size may also be explained by the low channel gradient and the ‘semi-alluvial’ nature of the stream. The relatively low sediment trans- port capacity only changes during extreme debris floods (Bywater-Reyes, S. et al. 2017). In the longitudinal profile four types were identified, such as stepped, irregular, lev- elled and undulating. The fifth possible type (toothed) was not observed. The occurrence of the observed types did not show a clear regu- larity along the stream. The four types being quite similar, only 60 of the measured sections the reaches could be classified unequivocal- ly. The vast majority of them (n = 49) were either irregular or levelled. However, the en- tire longitudinal profile of the studied stream displayed a concave curvature with a steep upper course (0–1,500 m) and a gentle lower course downstream (1,500–7,700 m) (see upper part of Photo 1), a typical longitudinal profile for alluvial streams (Rice, S.P. and Church, M. 2001). Earlier research also confirmed that nat- ural alluvial streams usually have an irregular longitudinal profile (Western, A.W. et al. 1997; Schumm, S.A. 2005). The width/depth ratio, measured in a total of 120 sections, characterises cross-section ge- ometry. The upstream segment (0–1,500 m) of the watercourse had a narrow and relatively deep valley floor with a low discharge (esti- mated mean annual discharge at the conflu- ence < 0.015 m3/s), resulting in an ill-defined stream channel. In the sections spanning from 30 to 155, the dominant types of beds were those whose width was much greater than depth. From 1,500 to 3,000 m, the width of the bed varied between 0.3 and 0.8 m (aver- age 0.54 m). Then, the width increased sig- nificantly. Up to the confluence, the width 373Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381. varied between 1.26 and 12.05 m (average 4.33 m). Channel depth was only measured from section 30 onwards. The 125 sections from here up to the confluence ranged from 0.05 to 1.2 m in depth (average is only 0.3 m). Deeper channels were often linked to anthropogen- ic influence. Moreover, the pools due to or- ganic dams or bedrock steps induced high- er-than-average values. The width/depth ratio (W/D) ranged from 2.5 to 143.2, with an average of 21.67 and was used for the funda- mental Rosgen’s classification (Rosgen, D.L. 1994). The first group consisted of forty-four sections with low values (W/D < 12; mean 8.56), which were dominated by alluvial deposits with floodplain and riffle/pool bed morphology. The next class (moderate W/D values between 12 and 40) characterised 69 sections (mean 21.24) with moderate or low channel gradient, riffle/pool bed mor- phology, and high bank-erosion anastomosed channel. In the third class (high W/D values > 40), 12 sections were included (mean 72.17) with broad valleys and considerable amounts of alluvial deposits. The channel types and bed morphology defined by the W/D values (Buffington, J.M. and Montgomery, D.R. 2013) can also be identified in the current study area. The slope, stability and maximum height of the natural banks were also surveyed since they significantly affect bank erosion and sed- iment transport (Sass, C.K. and Keane, T.D. 2012; Willett, C.D. et al. 2012; Buffington, J.M. and Montgomery, D.R. 2013). Banks were classified as very gentle, gentle, steep, vertical or overhanging along the stream. Establishing any regularity was not possible, as the pattern was found to be highly variable even within sections. The valley side charac- teristics were estimated in the upstream seg- ment (3–29) due to the lack of definite banks. Here the steep class predominated. With few exceptions, the downstream segment (30–155) was dominated by stable and semi-stable banks. The maximum relative height of the banks ranged from 0.2 to 3 m (average 1.06 m). It is important to note that in sections with vertical or overhanging bank types, the banks were still considered semi-stable due to anthropogenic influences (i.e., gabion walls) or to stabilising vegetation (Photo 2). The segment upstream had a steeper gra- dient (average 8.3%), whilst the downstream segment had only 2 percent. The downstream segment showed a consistently higher ratio (≥ 4%, n = 4) in sites where both bedrock out- crops and woody debris with a step system were present. Sections with a gradient of 2–4 percent (n = 48), either bedrock steps or woody debris, were reported in 39 cases. The entire longitudinal profile exhibited slope val- ues ranging from 0.44–16.9 percent. Bed slopes (0.2–1%), typical according to Bisson, P.A. et al. (2017), dominated on the pool-riffle reaches (n = 3 all downstream), 1–3 percent on the plane-bed reaches (n = 118 dominated down- stream), 3–8 percent on the step-pool reaches (n = 21) and 8–26 percent on the cascade stream reaches (n = 13 all upstream but not cascade types). Sinuosity ranged from 1 to 2.31 (mean: 1.12, standard deviation: 0.19). The sinuosity ratio (SR) of the whole valley (6,310 m) was also estimated as 1.22. Traditionally, channels are classified into three categories: straight (SR < 1.1), sinuous (1.1–1.5) and meandering (> 1.5) (Leopold, L.B. and Markley, G.W. 1957). In the sections we surveyed, straight type occurred in 63, sinuous in 21 and me- andering only in 4 cases (see Figure 3). We agreed with Charlton’s notes that the SR descriptions are confused in the literature, thus, making it hard to compare and inter- pret recent results (Charlton, R. 2008). The total number of large woody debris sites obstructing the riverbed was 48, located in 25 percent of the sections (n = 39). In most cases (79%), only one log jam per section was documented (n = 31 sections). The max- imum number of dams observed in a section was three, which occurred in only one case (section 109). The overall average was c. 0.62 WDJs per 100 m (Figure 4). The interpretation of our results is difficult since no similar survey has been conducted in the Pannonian Basin yet. However, the Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381.374 375Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381. ← Fig. 3. Longitudinal profile of Öreg-patak (Öreg Stream) with the main measured stream channel characteristics (on the right side axis, 1–15). Geology (1) = Lower Jurassic Pliensbachian marl (i); Lower Jurassic Pliensbachian marl and marlstone (ii); Lower Jurassic Pliensbachian marl and siltstone (iii); Lower Jurassic Toarcian marl and silt (iv); Lower Cretaceous (Valanginian) alkaline basalts (v). Surface of outcrops (2) = <10% (a); 10–50% (b); 50–90% (c). Woody debris (3). Genetic type of sediment (4) = slope origin (A); alluvial (B). Size composition of sediments (5) = clay (A); silt (B); sand (C); granules, 2–8 mm (D); pebbles, 8–64 mm (E); cobbles, 64–256 mm (F); boulders, > 256 mm (G). Cross-section of the channel (6) = triangular, depth > width (d); trapezoidal, depth = width (e); (f) elliptical, depth < width (f); parabolic, depth < width (g). Longitudinal profile (7) = atepped (A); irregular (C); levelled (D); undulating(E). Bank slope (8) = very gentle banks (A); gentle banks (B); steep banks (C); vertical banks (D); overhanging banks (E). River bank fixation (9) = naturally fixed (A); artificially fixed – biologically (B); artificially fixed – technically (C); unfixed (E). Stream gradient (10). Max bankfull width (1). Max height of the natural banks (12). Max bankfull depth (all in metre) (13). Channel shape index (14). Sinuosity (15). Photo 2. Examples of semi-stable stream banks: Technically fixed by retaining gabion walls (a), naturally semi- fixed by roots (b). (Photos taken by the authors.) Fig. 4. Map of the woody debris along the Öreg-patak (Öreg Stream): Borderline of the study area (A), perennial/ ephemeral stream (B/C), woody debris (D). Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381.376 frequency of WDJ is considered extremely low. Previous studies measured significantly higher values (range 2.4 to 8.6) with match- ing catchment areas (≤ 10 km2) and compa- rable reach lengths (≤ 50 m) (Jackson, K.J. and Wohl, E. 2015.). A higher value (1.2–1.4) with similar catchment parameters (channel length approx. 8 km, stream order HS ≥ 2, forested ratio close to 100%) was also report- ed (Comiti, F. et al. 2006). We assumed that low WDJ frequency is predominantly related to regular forest management, as the man- aged forest provides less wood than the old- growth forest to develop jams (Dahlström, N. and Nilsson, C. 2004; Motta, R. et al. 2006; Wohl, E. et al. 2017). The composition of debris jams (grain size, length, and diam- eter) varied along the stream. All surveyed WDJ contained organic material of the small- est dimension (leaves, seeds, and twigs) as well as elements classified in the literature as coarse woody debris (CWD) and large woody debris (LWD). This hybrid structure and grain size are consistent with most WDJ in the forest-covered headwater channels in low-mountainous regions (Manners, R.B. et al. 2007; Přibyla, Z. et al. 2016). The CWD and LWD consisted of pieces from decidu- ous trees dominated by agus sylvatica and Carpinus betulus. The increased ratio of Fagus sylvatica in the WDJ and other in-stream wood material has also been observed in the Czech Carpathians when this species is mixed with conifers to a much greater extent (Galia, T. et al., 2017). It may be assumed that Fagus syl- vatica has a unique role in WDJ generation in Central European low- and mid-mountain- ous mixed forests. Photo 3. Examples of woody debris jams (arrows show the flow direction): Log jam in juvenile phase (a), log jam with massive trunk and soil ball (b), typical log jam in mature phase (c), log jam with steps and pothole (d). (Photos taken by the authors.) 377Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381. A separate group is formed by types that usually contain massive trunks (≥ 25–30 cm diameter, ≥ 2 m length) typically found in the bed with soil ball (n = 3), all of them Fagus syl- vatica. These are referred to as stable types in this study, as their potential for displacement is relatively small, mainly due to their large mass and low average discharge of the trunk stream. They form a step in the bed, enhance the accumulation of sediment and the upwelling of wood, and promote the creation of erosional depressions after blockage. This way, they also have a complex and essential influence on bed morphology (Photo 3). Our findings on this issue are the same as Ondráčková and Máčka’s re- sults on the role of in-stream wood and rootball accumulations (Ondráčková, L. and Máčka, Z. 2019). Geomorphic (dis)connectivity in a middle-mountain context: Human interventions in the landscape. Furthermore, we consider the type we defined as stable WDJ comparable to the “active jam” type published by Cashman, M.J. et al. (2021), which increases the jam’s structural complexity and hydromorphological diversity. Conclusions This study delineated the Öreg-patak water- shed using standard GIS processes on a 10 m DEM. To estimate FFS for the catchment, we evaluated the computed parameters of the ba- sin and the modelled data for this area. The FFS of the studied watershed can be assessed as medium to moderate. However, extreme meteorological events can generate severe sed- iment and woody debris ‘floods’, easily ob- served during the fieldwork, especially in the upstream segment. With slight modifications and additions, the method we developed and utilised for the field survey of stream morphol- ogy was successfully applied in the Mecsek Hills and low-mountainous relief. Channel types and reaches were surveyed based on measured and estimated streambed morphological properties and classified accord- ing to a currently accepted geomorphological system (Buffington, J.M. and Montgomery, D.R. 2013). The upstream part was identified as a colluvial channel of 0 or 1 stream order and low streamflow discharge, incised into a colluvial valley. On the downstream segment, step-pool (steps formed by woody debris and bedrock), pool-riffle (moderate or low gradient) and braided channel (large W/D ratio) types dominated without any regularity. The bedrock channel reach occurred in less than 2 percent of all measured sections; the typical cascade, plane-bed and dune-ripple stream reaches could not be observed in the study area. The measured and estimated sporadic data of the natural streambanks (e.g. height, stability, and slope) may be suitable to de- termine the potential stages of bank erosion activity (Rosgen’s BEHI Index) at different levels. In this study, we recorded all woody debris jams in the channel, built up of either CWD or LWD. We focused on the ‘stable’ type of these log jams because they significantly af- fect streambed morphology. Forming natural barriers in the channel, wood jams can block or reduce sediment and organic material transport. Furthermore, their stability can be increased by travertine formation. Analysis of small headwater streams is lacking in Hungary as fluvial geomorpholog- ical studies focus mainly on larger rivers and their floods. However, increasingly frequent extreme rainfall events and flash floods jus- tify complex morphological studies of small catchments and headwater streams. Acknowledgement: We sincerely thank the anony- mous Reviewers for their useful and comprehensive comments on the manuscript, and we greatly ap- preciate their time and effort spent in this paper. This research was funded by the Higher Education Institutional Excellence Program of Ministry of Human Capacities (Hungary), grant number “20765- 3/2018/FEKUTSTRAT” at the University of Pécs and the Hungarian National Office for Research and Innovation (project GINOP-2.3.2-15-2016-00055). The authors also grateful to the Mecsek Forestry Co. Ltd. (Mecsekerdő Zrt.) and the South-Transdanubian Water Management Directorate (Dél-Dunántúli Vízügyi Igazgatóság, DDVIZIG) for providing data for the current research. The authors sincerely thank graduate students (Beáta Farkas, Máté Kiss, Frida Král, Emese Soltész) and Gábor Víg for their as- sistance during the fieldwork. Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381.378 REFERENCES Abbe, T.B. and Montgomery, D.R. 2003. Patterns and processes of wood debris accumulation in the Queets river basin, Washington. Geomorphology 51. (1–3): 81–107. Available at https://doi.org/10.1016/ S0169-555X(02)00326-4 Abdel-Fattah, M., Saber, M., Kantoush, S.A., Khalil, M.F., Sumi, T. and Sefelnasr, A. M. 2017. A hydrological and geomorphometric approach to understanding the generation of wadi flash floods. Water 9. (7): 553. Available at https://doi.org/10.3390/ w9070553 Ádám, L., Marosi, S. and Szilárd, J. (eds.). 1981. Magyarország tájföldrajza 4. A Dunántúli-dombság – Dél-Dunántúl (Landscape geography of Hungary 4. Transdanubian Hills – South Transdanubia). Budapest, Akadémiai Kiadó. Alam, A., Ahmed, B. and Sammonds, P. 2020. Flash flood susceptibility assessment using the parameters of drainage basin morphometry in SE Bangladesh. Quaternary International 575–576. 295–307. Available at https://doi.org/10.1016/j. quaint.2020.04.047 Bilby, R.E. and Likens, G.E. 1980. Importance of organic debris dams in the structure and function of stream ecosystems. Ecology 61. (5): 1107–1113. Available at https://doi.org/10.2307/1936830 Bilby, R.E. and Ward, J.W. 1991. Characteristics and function of large woody debris in streams draining old-growth, clear-cut, and second-growth forests in southwestern Washington. Canadian Journal of Fisheries and Aquatic Sciences 48. (12): 2499–2508. Available at https://doi.org/10.1139/f91-291 Bisson, P.A., Montgomery, D.R. and Buffington, J.M. 2017. Valley segments, stream reaches, and channel units. In Methods in Stream Ecology. Vol. 1. Eds.: Hauer, F.R. and Lamberti, G.A., Elsevier, 21–47. Available at https://doi.org/10.1016/B978-0- 12-416558-8.00002-0 Biswas, S.S. 2016. Analysis of GIS based morpho- metric parameters and hydrological changes in Parbati river basin, Himachal Pradesh, India. Journal of Geography & Natural Disasters 6. (2): 1000175. Available at https://doi.org/10.4172/2167- 0587.1000175 Buffington, J.M. and Montgomery, D.R. 2013. Geomorphic classification of rivers. In Treatise on Geomorphology. Ed.-in-Chief: Shroder, J.F. Elsevier, 730–767. Available at https://doi.org/10.1016/B978- 0-12-374739-6.00263-3 Bywater-Reyes, S., Segura, C. and Bladon, K.D. 2017. Geology and geomorphology control suspended sediment yield and modulate increases following timber harvest in temperate headwater streams. Journal of Hydrology 548. 754–769. Available at https://doi.org/10.1016/j.jhydrol.2017.03.048 Carter, C.D. and Marks, J.C. 2007. Influences of travertine dam formation on leaf litter decomposition and algal accrual. Hydrobiologia 575. (1): 329–341. Available at https://doi.org/10.1007/ s10750-006-0379-6 Cashman, M.J., Harvey, G.L. and Wharton, G. 2021. Structural complexity influences the ecosystem engineering effects of in-stream large wood. Earth Surface Processes and Landforms 46. (10): 2079–2091. Available at https://doi.org/10.1002/esp.5145 Charlton, R. 2008. Fundamentals of Fluvial Geomorphology. London, Routledge, Taylor and Francis Group. Comiti, F., Andreoli, A., Lenzi, M.A. and Mao, L. 2006. Spatial density and charactereistic of woody debris in five mountain rivers of the Dolomites (Italian Alps). Geomorphology 78. (1–2): 44–63. Available at https://doi.org/10.1016/j.geomorph.2006.01.021 Compson, Z.G., Mier, M.Z. and Marks, J.C. 2009. Effects of travertine and flow on leaf retention in Fossil Creek, Arizona. Hydrobiologia 630. (1): 187–197. Available at https://doi.org/10.1007/s10750- 009-9791-z Czigány, Sz., Pirkhoffer, E. and Geresdi, I. 2010. Impact of extreme rainfall and soil moisture on flash flood generetion. Időjárás 114. (1–2): 79–110. Dahlström, N. and Nilsson, C. 2004. Influence of woody debris on channel structure in old growth and managed forest streams in Central Sweden. Environmental Management 33. (3): 376–384. Available at https://doi.org/10.1007/s00267-003-3042-2 Daipan, B.P.O. 2020. Geomorphometric characteri- zation and analysis of the Bued Watershed using advanced spaceborne thermal emission and reflec- tion radiometer – Global Digital Elevation Model V3 through geospatial techniques. Philippine Journal of Science 149. (3a): 955–967. Esper Angillieri, M.Y. 2008. Morphometric analysis of Colangüil river basin and flash flood hazard, San Juan, Argentina. Environmental Geology 55. (1): 107–111. Available at https://doi.org/10.1007/ s00254-007-0969-2 ESRI 2011. ArcHydro Toolbox v2.0. Environmental Systems Research Institute. ESRI 2016. ArcGIS 10.4. Environmental Systems Research Institute. Fábián, Sz.Á., Kalmár, P., Józsa, E. and Sobucki, M. 2016. Hydrogeomorphic exploration of a local headwater stream in low mountainous environment following detailed field survey protocol (Mecsek Mountains, Hungary). Revista de Geomorfologie 18. 78–82. Fryirs, K.A. and Brierley, G.J. 2001. Variability in sediment delivery and storage along river courses in Bega catchment, NSW, Australia: implications for geomorphic river recovery. Geomorphology 38. (3–4): 237–265. Available at https://doi.org/10.1016/ S0169-555X(00)00093-3 https://doi.org/10.1016/S0169-555X(02)00326-4 https://doi.org/10.1016/S0169-555X(02)00326-4 https://doi.org/10.3390/w9070553 https://doi.org/10.3390/w9070553 https://doi.org/10.1016/j.quaint.2020.04.047 https://doi.org/10.1016/j.quaint.2020.04.047 https://doi.org/10.2307/1936830 https://doi.org/10.1139/f91-291 https://doi.org/10.1016/B978-0-12-416558-8.00002-0 https://doi.org/10.1016/B978-0-12-416558-8.00002-0 https://doi.org/10.4172/2167-0587.1000175 https://doi.org/10.4172/2167-0587.1000175 https://doi.org/10.1016/B978-0-12-374739-6.00263-3 https://doi.org/10.1016/B978-0-12-374739-6.00263-3 https://doi.org/10.1016/j.jhydrol.2017.03.048 https://doi.org/10.1007/s10750-006-0379-6 https://doi.org/10.1007/s10750-006-0379-6 https://doi.org/10.1002/esp.5145 https://doi.org/10.1016/j.geomorph.2006.01.021 https://doi.org/10.1007/s10750-009-9791-z https://doi.org/10.1007/s10750-009-9791-z https://doi.org/10.1007/s00267-003-3042-2 https://doi.org/10.1007/s00254-007-0969-2 https://doi.org/10.1007/s00254-007-0969-2 https://doi.org/10.1016/S0169-555X(00)00093-3 https://doi.org/10.1016/S0169-555X(00)00093-3 379Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381. Fryirs, K.A., Brierley, G.J., Preston, N.J. and Spencer, J. 2007. Catchment-scale (dis)connectivity in sediment flux in the upper Hunter catchment, New South Wales, Australia. Geomorphology 84. (3–4): 297–316. Available at https://doi.org/10.1016/j.geomorph.2006.01.044 Fuller, B., Sklar, L., Compson, Z., Adams, K., Marks, J. and Wilcox, A. 2011. Ecogeomorphic feedbacks in regrowth of travertine step-pool morphology after dam decommissioning, Fossil Creek, Arizona. Geomorphology 126. (3–4): 314–332. Available at https:// doi.org/10.1016/j.geomorph.2010.05.010 Galia, T. and Hradecký, J. 2011. Bedload transport and morphological effects of high-magnitude floods in small headwater streams – Moravskoslezské Beskydy Mts. (Czech Republic). Journal of Hydrology and Hydromechanics 59. (4): Available at https://doi. org/10.2478/v10098-011-0020-x Galia, T. and Škarpich, V. 2013. Coarse bed sediments in a headwater channel as indicators of fluvial process and slope-channel coupling: A case study from the Carpathian Mountains (Czech Republic). Moravian Geographical Reports 21. 2–11. Available at https://doi. org/10.2478/mgr-2013-0012 Galia, T. and Hradecky, J. 2014. Channel-reach morphology controls of headwater streams based in flysch geologic structures: An example from the Outer Western Carpathians, Czech Republic. Geomorphology 216. 1–12. Available at https://doi.org/10.1016/j. geomorph.2014.03.026 Galia, T., Hradecký, J. and Škarpich, V. 2015. Sediment transport in headwater streams of the Carpathian Flysch Belt: Its nature and recent effects of human interventions. In Sediment Matters. Eds.: Heininger, P. and Cullmann, J., Springer International Publishing, 13–26. Available at https://doi.org/10.1007/978-3- 319-14696-6_2 Galia, T., Šilhán, K., Ruiz-Villanueva, V., Tichavský, R. and Stoffel, M. 2017. Temporal dynamics of instream wood in headwater streams draining mixed Carpathian forests. Geomorphology 292. 35–46. Available at https://doi.org/10.1016/j.geomorph.2017.04.041 Galia, T., Ruiz-Villanueva, V., Tichavský, R., Šilhán, K., Horáček, M. and Stoffel, M. 2018. Characteristics and abundance of large and small instream wood in a Carpathian mixed-forest headwater basin. Forest Ecology and Management 424. 468–482. Available at https://doi.org/10.1016/j.foreco.2018.05.031 Grabowski, R.C., Gurnell, A.M., Burgess-Gamble, L., England, J., Holland, D., Klaar, M.J., Morrissey, I., Uttley, C. and Wharton, G. 2019. The current state of the use of large wood in river restoration and manage- ment. Water and Environment Journal 33. (3): 366–377. Available at https://doi.org/10.1111/wej.12465 Gurnell, A.M. and Grabowski, R.C. 2016. Vegetation- hydrogeomorphology interactions in a low- energy, human-impacted river. River Research and Applications 32. (2): 202–215. Available at https://doi. org/10.1002/rra.2922 Haas, J. (ed.). 2013. Geology of Hungary. Berlin–Heidelberg, Springer. Available at https://doi.org/10.1007/978-3- 642-21910-8 Horton, R.E. 1945. Erosional development of streams and their draniage basins; Hydrophysical approach to quantiative morphology. Geologocal Society of America Bulletin 56. (3): 275. Hungarian Meteorological Service (n.d.) Climate of Hungary – general characteristics. Budapest, OMSZ. Retrieved 10 October 2021 from https://www.met. hu/en/eghajlat/magyarorszag_eghajlata/altalanos_ eghajlati_jellemzes/altalanos_leiras/ Jackson, K.J. and Wohl, E. 2015. Instream wood loads in montane forest streams of the Colorado Front Range, USA. Geomorphology 234. 161–170. Available at https:// doi.org/10.1016/j.geomorph.2015.01.022 Jeffries, R., Darby, S.E. and Sear, D.A. 2003. The influence of vegetation and organic debris on flood-plain sediment dynamics: case study of a low-order stream in the New Forest, England. Geomorphology 51. (1–3: 61–80. Available at https://doi.org/10.1016/S0169- 555X(02)00325-2 Kalmár, P., Fábián, Sz.Á. and Sobucki, M. 2013. Esettanulmány a természetes vízfolyások felszín- formálásáról: A Váraljai-árok északi forrásága a Mecsekben (A case study about the surface shaping of natural waterflows: The northern springbranch of Váralja Trench in the Mecsek Hills). Természetföldrajzi Közlemények a Pécsi Tudományegyetem Földrajzi Intézetéből 2. Pécs, PTE. Kalmár, P. 2015. Terepi morfometriai és -dinamikai vizs- gálatok a Váraljai-völgy vízgyűjtőjén (Morphometric and morphodinamic measures on the Váralja Valley catchment). Pécs, PTE-TTK, Földrajzi Intézet. Kamykowska, M., Kaszowski, L. and Krzemien, K. 1999. River channel mapping instruction. Key to the river bed descreption. In River Channels. Pattern, Structure and Dynamics. Ed.: Krzemien, K., Cracow, Poland, Institute of Geography of the Jagiellonian University, 9–25). Kaszowski, L. and Krzemien, K. 1999. Classification systems of mountain river channel. Prace Geograficzne IG UJ 104. 27–40. Kevey B. 2008. Magyarország erdőtársulásai. XIV. kötet (Forest associations of Hungary. Vol. XIV). Ed.: Bartha, D., Sopron, NYME Erdőmérnöki kar. Kocsis, K. (ed.-in-chief). 2018. National Atlas of Hungary, 2. Natural Environment. Budapest, MTA Research Centre of Astronomy and Earh Sciences, Geographical Institute. Leopold, L.B. and Markley, G.W. 1957. River Channel Patterns: Braided, Meandering, and Straight. Washington, D.C., USGS Publications Warehouse. Doi 10.3133/ pp282B Lóczy, D. 2012. A folyómedrek morfológiai tipizálásának hierarchiája a nemzetközi irodalomban (Hierarchical presentation of typologies of river channel morphology in international literature). Földrajzi Közlemények 136. (2): 124–137. https://doi.org/10.1016/j.geomorph.2006.01.044 https://doi.org/10.1016/j.geomorph.2010.05.010 https://doi.org/10.1016/j.geomorph.2010.05.010 https://doi.org/10.2478/v10098-011-0020-x https://doi.org/10.2478/v10098-011-0020-x https://doi.org/10.2478/mgr-2013-0012 https://doi.org/10.2478/mgr-2013-0012 https://doi.org/10.1016/j.geomorph.2014.03.026 https://doi.org/10.1016/j.geomorph.2014.03.026 https://doi.org/10.1007/978-3-319-14696-6_2 https://doi.org/10.1007/978-3-319-14696-6_2 https://doi.org/10.1016/j.geomorph.2017.04.041 https://doi.org/10.1016/j.foreco.2018.05.031 https://doi.org/10.1111/wej.12465 https://doi.org/10.1002/rra.2922 https://doi.org/10.1002/rra.2922 https://doi.org/10.1007/978-3-642-21910-8 https://doi.org/10.1007/978-3-642-21910-8 https://www.met.hu/en/eghajlat/magyarorszag_eghajlata/altalanos_eghajlati_jellemzes/altalanos_leiras/ https://www.met.hu/en/eghajlat/magyarorszag_eghajlata/altalanos_eghajlati_jellemzes/altalanos_leiras/ https://www.met.hu/en/eghajlat/magyarorszag_eghajlata/altalanos_eghajlati_jellemzes/altalanos_leiras/ https://doi.org/10.1016/j.geomorph.2015.01.022 https://doi.org/10.1016/j.geomorph.2015.01.022 https://doi.org/10.1016/S0169-555X(02)00325-2 https://doi.org/10.1016/S0169-555X(02)00325-2 Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381.380 Manners, R.B., Doyle, M.W. and Small, M.J. 2007. Structure and hydraulics of natural woody de- bris jams. Water Resources Research 43. (6): 1–16. Available at https://doi.org/10.1029/2006WR004910 Mesa, L.M. 2006. Morphometric analysis of a sub- tropical Andean basin (Tucumán, Argentina). Environmental Geology 50. (8): 1235–1242. Available at https://doi.org/10.1007/s00254-006-0297-y Mezősi, G. 2015. Magyarország természetföldrajza (Physical geography of Hungary). Budapest, Akadémiai Kiadó. Available at https://doi. org/10.1556/9789630589765 Moores, E.A. 1966. Regional Drainage Basin Morphometry. Ames, Iowa State University, Digital Repository. Available at https://doi.org/10.31274/ rtd-180814-1017 Morisawa, M.E. 1962. Quantitative geomorphology of some watersheds in the Appalachian Plateau. GSA Bulletin 73. (9): 1025–1046. Available at https:// doi.org/10.1130/0016-7606(1962)73[1025:QGOS- WI]2.0.CO;2 Motta, R., Berretti, R., Lingua, E. and Piussi, P. 2006. Coarse woody debris, forest structure and regen- eration in the Valbona Forest Reserve, Paneveggio, Italian Alps. Forest Ecology and Management 235. (1–3): 155–163. Available at https://doi.org/10.1016/j. foreco.2006.08.007 Myers, T.J. and Swanson, S. 1997. Precision of channel width and pool area measurments. Journal of the American Water Resources Association 33. (3): 647–659. Available at https://doi. org/10.1111/j.1752-1688.1997.tb03539.x Obeidat, M., Awawdeh, M. and Al-Hantouli, F. 2021. Morphometric analysis and prioritisation of watersheds for flood risk management in Wadi Easal Basin (WEB), Jordan, using geospatial technologies. Journal of Flood Risk Management 14. (2): e12711. Available at https://doi.org/10.1111/ jfr3.12711 Ondráčková, L. and Máčka, Z. 2019. Geomorphic (dis)connectivity in a middle-mountain context: Human interventions in the landscape modify catchment-scale sediment cascades. Area 51. (1): 113–125. Available at https://doi.org/10.1111/ area.12424 Pareta, K. and Pareta, U. 2011. Quantitative mor- phometric analysis of a watershed of Yamuna Basin, India using ASTER (DEM) data and GIS. International Journal of Geomatics and Geosciences 2. (1): 248–269. Płaczkowska, E., Górnik, M., Mocior, E., Peek, B., Potoniec, P., Rzonca, B. and Siwek, J. 2015. Spatial distribution of channel heads in the Polish Flysch Carpathians. CATENA 127. 240–249. Available at https://doi.org/10.1016/j.catena.2014.12.033 Płaczkowska, E. 2016. Structure of the headwater valley segment in the Western Tatras. Studia Geomorphologica Carpatho-Balcanica 50. 89–103. Płaczkowska, E. and Krzemień, K. 2018. Natural conditions of coarse bedload transport in headwater catchments (Western Tatras, Poland). Geografiska Annaler: Series A, Physical Geography 100. (4): 370–387. Available at https://doi.org/10.1080/0435 3676.2018.1522957 Přibyla, Z., Galia, T. and Hradecký, J. 2016. Biogeomorphological effects of leaf accumulations in stepped-bed channels: Exploratory study, Moravskoslezské Beskydy Mountains, Czech Republic. Moravian Geographical Reports 24. (3): 13–23. Available at https://doi.org/10.1515/mgr- 2016-0013 Prokop, P., Wiejaczka, Ł., Sarkar, S., Bryndal, T., Bucała-Hrabia, A., Kroczak, R., Soja, R. and Płaczkowska, E. 2020. Morphological and sedimentological responses of small stream channels to extreme rainfall and land use in the Darjeeling Himalayas. CATENA 188. 104444. Available at https://doi.org/10.1016/j. catena.2019.104444 Puno, G.R. and Puno, R.C.C. 2019. Watershed conservation prioritization using geomorphometric and land use-land cover parameters. Global Journal of Environmental Science and Management 5. (3): 279–294. Available at https://doi.org/10.22034/ GJESM.2019.03.02 Raucsik, B. and Varga, A. 2008. Az alsó-toarci fekete- pala Réka-völgyi szelvényének ásványtani jellem- zése (Óbányai Alurolit Formáció, Mecsek hegy- ség): őséghajlattani következtetések (Mineralogy of the Lower Toarcian black shale section from the Réka Valley [Óbánya Siltstone Formation, Mecsek Mountains, Hungary]: implications for palaeoclimate). Földtani Közlöny 138. (2): 133–146. Rice, S.P. and Church, M. 2001. Longitudinal profiles in simple alluvial systems. Water Resources Research 37. (2): 417–426. Available at https://doi. org/10.1029/2000WR900266 Rosgen, D.L. 1994. A classification of natural rivers. CATENA 22. (3): 169–199. Available at https://doi. org/10.1016/0341-8162(94)90001-9 Ruiz Villanueva, V., Bladé Castellet, E., Díez- Herrero, A., Bodoque, J. M. and Sánchez-Juny, M. 2014. Two-dimensional modelling of large wood transport during flash floods. Earth Surface Processes and Landforms 39. (4): 438–449. Available at https:// doi.org/10.1002/esp.3456 Russel, R.J. 1954. Alluvial morphology of Anatolian rivers. Annals of the Association of American Geographers 55. (4): 363–391. Sarkadi, N., Pirkhoffer, E., Lóczy, D., Balatonyi, L., Geresdi, I., Fábián, Sz., Varga, G., Balogh, R., Gradwohl-Valkay, A., Halmai, Á. and Czigány, Sz. 2022. Generation of a flood susceptibility map of evenly weighted conditioning factors for Hungary. Geographica Pannonica 26. (3): 200–214. Available at https://doi.org/10.5937/gp26-38969 https://doi.org/10.1029/2006WR004910 https://doi.org/10.1007/s00254-006-0297-y https://doi.org/10.1556/9789630589765 https://doi.org/10.1556/9789630589765 https://doi.org/10.31274/rtd-180814-1017 https://doi.org/10.31274/rtd-180814-1017 https://doi.org/10.1130/0016-7606(1962)73%5b1025:QGOSWI%5d2.0.CO;2 https://doi.org/10.1130/0016-7606(1962)73%5b1025:QGOSWI%5d2.0.CO;2 https://doi.org/10.1130/0016-7606(1962)73%5b1025:QGOSWI%5d2.0.CO;2 https://doi.org/10.1016/j.foreco.2006.08.007 https://doi.org/10.1016/j.foreco.2006.08.007 https://doi.org/10.1111/j.1752-1688.1997.tb03539.x https://doi.org/10.1111/j.1752-1688.1997.tb03539.x https://doi.org/10.1111/jfr3.12711 https://doi.org/10.1111/jfr3.12711 https://doi.org/10.1111/area.12424 https://doi.org/10.1111/area.12424 https://doi.org/10.1016/j.catena.2014.12.033 https://doi.org/10.1080/04353676.2018.1522957 https://doi.org/10.1080/04353676.2018.1522957 https://doi.org/10.1515/mgr-2016-0013 https://doi.org/10.1515/mgr-2016-0013 https://doi.org/10.1016/j.catena.2019.104444 https://doi.org/10.1016/j.catena.2019.104444 https://doi.org/10.22034/GJESM.2019.03.02 https://doi.org/10.22034/GJESM.2019.03.02 https://doi.org/10.1029/2000WR900266 https://doi.org/10.1029/2000WR900266 https://doi.org/10.1016/0341-8162(94)90001-9 https://doi.org/10.1016/0341-8162(94)90001-9 https://doi.org/10.1002/esp.3456 https://doi.org/10.1002/esp.3456 https://doi.org/10.5937/gp26-38969 381Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381. Sass, C.K. and Keane, T.D. 2012. Application of Rosgen’s BANCS model for NE Kansas and the development of predictive streambank erosion curves. Journal of the American Water Resources Association 48. (4): 774–787. Sassolas-Serrayet, T., Cattin, R. and Ferry, M. 2018. The shape of watersheds. Nature Communications 9. (1): 3791. Available at https://doi.org/10.1038/ s41467-018-06210-4 Schumm, S.A. 1956. Evolution of drainage systems and slopes in badlands at Perth Amboy, New Jersey. Bulletin of the Geological Society of America 67. 597–646. Schumm, S.A. 2005. River Variability and Complexity. Cambridge, Cambridge University Press. Available at https://doi.org/10.1017/CBO9781139165440 Short, L.E., Gabet, E.J. and Hoffman, D.F. 2015. The role of large woody debris in modulating the dispersal of a post-fire sediment pulse. Geomorphology 246. 351–358. Available at https:// doi.org/10.1016/j.geomorph.2015.06.031 Singh, P., Thakur, J.K. and Singh, U.C. 2013. Morphometric analysis of Morar River Basin, Madhya Pradesh, India, using remote sensing and GIS techniques. Environmental Earth Sciences 68. (7): 1967–1977. Available at https://doi.org/10.1007/ s12665-012-1884-8 Strahler, A.N. 1957. Quantitative analysis of watershed geomorphology. Transactions, American Geophysical Union 38. (6): 913. Available at https:// doi.org/10.1029/TR038i006p00913 Thompson, M.S.A., Brooks, S.J., Sayer, C.D., Woodward, G., Axmacher, J.C., Perkins, D.M. and Gray, C. 2018. Large woody debris “rewilding” rapidly restores biodiversity in riverine food webs. Journal of Applied Ecology 55. (2): 895–904. Available at https://doi.org/10.1111/1365-2664.13013 Víg, B., Fábian, Sz.Á., Czigány, Sz., Pirkhoffer, E., Halmai, Á., Kovács, I.P., Varga, G., Dezső, J., Nagy, G. and Lóczy, D. 2022. Morphometric analysis of low mountains for mapping flash flood susceptibility in headwaters. Natural Hazards 114. (3): 3235–3254. Available at https://doi.org/10.1007/ s11069-022-05513-6 Western, A.W., Finlayson, B.L., McMahon, T.A. and O’Neill, I.C. 1997. A method for characterising longitudinal irregularity in river channels. Geomorphology 21. (1): 39–51. Available at https:// doi.org/10.1016/S0169-555X(97)00023-8 Willett, C.D., Lerch, R.N., Schultz, R.C., Berges, S.A., Peacher, R.D. and Isenhart, T.M. 2012. Streambank erosion in two watersheds of the Central Claypan Region of Missouri, United States. Journal of Soil and Water Conservation 67. (4): 249–263. Available at https://doi.org/10.2489/jswc.67.4.249 Wohl, E., Lininger, K.B., Fox, M., Baillie, B.R. and Erskine, W.D. 2017. Instream large wood loads across bioclimatic regions. Forest Ecology and Management 404. 370–380. Available at https://doi. org/10.1016/j.foreco.2017.09.013 Zhang, N., Rutherfurd, I. and Ghisalberti, M. 2020. Effect of instream logs on bank erosion potential: a flume study with a single log. Journal of Ecohydraulics 5. (1): 43–56. Available at https://doi. org/10.1080/24705357.2019.1634499 https://doi.org/10.1038/s41467-018-06210-4 https://doi.org/10.1038/s41467-018-06210-4 https://doi.org/10.1017/CBO9781139165440 https://doi.org/10.1016/j.geomorph.2015.06.031 https://doi.org/10.1016/j.geomorph.2015.06.031 https://link.springer.com/article/10.1007/s12665-012-1884-8 https://link.springer.com/article/10.1007/s12665-012-1884-8 https://doi.org/10.1029/TR038i006p00913 https://doi.org/10.1029/TR038i006p00913 https://doi.org/10.1111/1365-2664.13013 https://doi.org/10.1007/s11069-022-05513-6 https://doi.org/10.1007/s11069-022-05513-6 https://doi.org/10.1016/S0169-555X(97)00023-8 https://doi.org/10.1016/S0169-555X(97)00023-8 https://doi.org/10.2489/jswc.67.4.249 https://doi.org/10.1016/j.foreco.2017.09.013 https://doi.org/10.1016/j.foreco.2017.09.013 https://doi.org/10.1080/24705357.2019.1634499 https://doi.org/10.1080/24705357.2019.1634499 Víg, B. et al. Hungarian Geographical Bulletin 72 (2023) (4) 365–381.382 Hungarian Geographical Bulletin Vol 72 Issue 4 365-381 Channel-reach morphometric analysis on a headwater stream in a low-mountainous region: A case study from Mecsek Hills