ASSESSMENT OF CHECK DAMS FILLING IN A MID-MOUNTAIN ASSESSMESNTRTEOAFMCHBAESCEKDDAONMTSRFEEILLRIINNGGIANAN A MLYIDS-EMSOUNTAIN ST(RTEHAEM EABSATESERND OSNUDTRETEEESRMINOGUNANATALINYSS)ES (THE EASTERN MOUNTAINS) Ireneusz Malik1, Piotr Owczarek2 Ireneusz Malik1, Piotr Owczarek2 STUDY AREA STUDY AREA The study area is located in the upper part of the Cerny Potok catchment in the Eastern TSudheestetus dMyounareataiinss lcaocalleteddthienJtehsenuppiki Merounparttaionfs (thnoertCheearnsytePrnotCokzecchatRchempubenlit c i)n. the Eastern TSudheetSeuds Metounes t Maiounns catallinesd tbheelongJesentiokiaMounvastt a lionws (nomrounth eatasinterrnaCngzeechthRatepfubormlice)d. during the HTheercySnudianeteOs ro Mgounenyt,aianns ebveelongnt wthoicha pvraodust lcoewd numounmertouains rmanounge tathinat rafonrgmeseda nd durisnoglatehde mHearsscyifnsiainn COenrotrgaelnaynd, aWn eestveernntEwurhoipche. Sptruodudycweads lnuocamteerdouins CmerounventaiHn orraanmgeasssiafndwhiiscohlawteads omraigssinifaslliyncCovenetrreadl abndy bWeeecshtearndn Emiurxoepde.fSorteusdty, gwradsuloalcalytegdiviinngCewravyentao Hsporruacemfaossreisftws ahtichhigwhaesr eolreigviantiaonllys.cTovheisrevdebgeytabtieeonch haands bmieenxerdepfloaceresdt, bgyrasdpuraulcely gmivonoingcuwltauyretos; stphreucheigfhoersets ttsreeatshbigehinegr pelleavnatetidonabovs. Tehitsheveogreigtaintiaonl tim hasbebrelienner(e1,250placed– b1,300y spr umceam.s.onol.). cTuhlteurraeisn;f athlle ihnigthheesrte streaeerschbeairneag apvlaenrategdesabovabouetth1,500e origmminal/ ytimearb.eTrlihneele(1,250ngth o–f t1,300he sec mtiona.s o.lf.)t.hTehCeerraniynfPallot okin tshterearemseaarncahlyazreead aisve2.2rag e ksma.bouThte1,500streammmch/aynneare.l T ihsemleaningltyh ionfctihsedsecwtiitonhin oafllthuveiCalerdneypoPsoittoks, bustrteaomccasniaonlyazleldy pisass2.2es kshom.rtTshecetisontreas mof bcehdarnnocek.l iTshme aminalxyiminacl iisnecdlinweitohfinthaell cuvhainnaledl eipos 19sit.5s, % bu. tTwococ apsaironts acallny bpeassdeisti snhogurtisshecedtioninsthoef bCeedrrnoyck.PoTthoke mstarxeaimmalca intchlimneenotf. tTheh echuppanneerl ipsa19rt .f5or%m.sTtwheo speadrtims caennt sbuppe dilsytiznongueis,hwedheirne tehreosCioneranlypProocetokssesstreadommicanattceh. mInentht.isTphaertupp, deebrripsafrltowfosrmdusritnhge suedmmimenrst sauppnd slynozwonaev, awlahnecrhee esroinsionwianlteprroaceresobsessedorvmied.naItne.thIne tlhoiwsepraprta,rdt eobfritshefloawnaslyduzerdingcastuchmmmeenrts, dandepossnoitionw aalvparlaoncechsseessidnowmiinntaetre.aTreheobflsuverviaeld.deIpnotshite islocaweprtupreadrt boyf tthhee saynsatelymzeodf cfaivtceh cmheecntk, daemposs,itiwonhicahl paroecespsrseeasddoovmiernaa400te. Tmheseflcuvtionial odfetphoessitt rieas mcapcthuarnnedebl.y the system of five check dams, which are spread over a 400 m section of the stream channel. METHODS METHODS The 400 m of the Cerny Potok stream were surveyed by using a tape-measure, and a Frieberg 59Theco400mpamsso. fTthhee voCelrunmyePotfoksedstimreaemntswdeerpoe ssuitrevdeyupedstbryeaumsinogf athtea pceh-ecmkea dsaumres, awndasaeFstimriebaeterdg 59basceodm onpa tsshe. Tarheeavoandlumdepothf soefdaimcceunmtsuldaetpoedsmiteadteupriasl.trTeahme doefndthreo cchhreconok ldoagmicsalw ianvs estitimgaatitoedn wbaassedb aonse dt hone a2r ema eatndhoddse potfhs toufdaycc. Fuimrsut,lagtreodwmthatreinrigalw. Tidhthe dreedundcrtioonchrsonoof l25ogiscparlu icenvs,esgtirogwatiingon wupasstrbeaasmed t hone c2h mecekthoddams sofofstuthdey.CFeirrnsyt, Pgrootwokthstrrieangmw, iwdtehreredduatcetid.onTshoefse25treespsruwceesr,egbrouwrrinngg wupitshtreasemdim theen tcahndecksodmametims oefsthweoundCerneyd Pbyottokransstpreaormted, wmearteerdiaaltead.ndTahbersueptrgeeroswwtherreedubucrrtiionng rweitsuhltseeddimfroemnt tahndis psroomcesstim. eAs lwooundcal chedronobylotrgaynswpoarstecdonmsatrtuecritaeldafrndomab1ru5plit vgirnogwtshprruecdue ctrtieoens grersouwltiendg fronomC etrhviesnparoHcoerssa.mAassloifcatlo cchormonopalroegtyrewe arisngconvasrtirauticonted ofrf obumrr1e5d alindvinwgoundspruceed trees agndrowtirnegesongroCwerivnegn oua Htsoidrae mofassdeifpotositicoonmaplazreontree.eSrecinondg valryiaetixonpo soufrbue orfre1d5androowtsoundwereeddatrteeed.s Randoottsreoefs sgprrouwceinsgg ourowtsidneg oupf sdtereapomsitioonf athlezondaem. sSecareondexlpoy esxedpoassurae roefsu1l5t oroof ltastewraelreerdoastieod.n wRoohicths o ofccsuprrrueced safgteror w reinsegrvoupisrtsreawmereofenttihereldyamfills eadr.e Dexapotinsgedofasgraowrethsulrteduofcltiaontersalanderosriooont wexhpoichsu r oecc aullrorweds daeftteecr ti rensgeervoveinrtss wehreen ethnetirdealmy frillesedrvo. Dirastiwnegreofillgerd.owth reductions and root exposure allows detecting events when the dam reservoirs were filled. RESULTS AND CONCUSIONS RESULTS AND CONCUSIONS

1 University of , Faculty of Earth Sciences, Bedzinska 60, 41-200 Sosnowiec, (Tel.: +48-032-380- 9104; Fax: +48-032-380-9104; email: [email protected]) 1 University of Silesia, Faculty of Earth Sciences, Bedzinska 60, 41-200 Sosnowiec, Poland (Tel.: +48-032-380- 2 Uiversity of Wroclaw, Institute of Geography and Regional Development, 50-138 Wroclaw, Poland (Tel.: +48- 9104; Fax: +48-032-380-9104; email: [email protected]) 071-375-2233; Fax: +48-071-343-5184 email: [email protected]) 2 Uiversity of Wroclaw, Institute of Geography and Regional Development, 50-138 Wroclaw, Poland (Tel.: +48- 071-375-2233; Fax: +48-071-343-5184 email: [email protected])

– 268 – – 269 – ASSESSMENT OF CHECK DAMS FILLING IN A MID-MOUNTAIN STREAM BASED ON TREE RING ANALYSES (THE EASTERN SUDETES MOUNTAINS)

Ireneusz Malik1, Piotr Owczarek2

STUDY AREA

The study area is located in the upper part of the Cerny Potok catchment in the Eastern Sudetes Mountains called the Jeseniki Mountains (north eastern ). The Sudetes Mountains belong to a vast low mountain range that formed during the Hercynian Orogeny, an event which produced numerous mountain ranges and isolated massifs in Central and Western Europe. Study was located in Cervena Hora massif which was originally covered by beech and mixed forest, gradually giving way to spruce forests at higher elevations. This vegetation has been replaced by spruce monocultures; the highest trees being planted above the original timberline (1,250 – 1,300 m a.s.l.). The rainfall in the research area averages about 1,500 mm/year. The length of the section of the Cerny Potok stream analyzed is 2.2 km. The stream channel is mainly incised within alluvial deposits, but occasionally passes short sections of bedrock. The maximal incline of the channel is 19.5 %. Two parts can be distinguished in the Cerny Potok stream catchment. The upper part forms the sediment supply zone, where erosional processes dominate. In this part, debris flows during summers and snow avalanches in winter are observed. In the lower part of the analyzed catchment, depositional processes dominate. The fluvial deposit is captured by the system of five check dams, which are spread over a 400 m section of the stream channel.

METHODS

The 400 m of the Cerny Potok stream were surveyed by using a tape-measure, and a Frieberg 59 compass. The volume of sediments deposited upstream of the check dams was estimated based on the area and depth of accumulated material. The dendrochronological investigation was based on 2 methods of study. First, growth ring width reductions of 25 spruces, growing upstream the check dams of the Cerny Potok stream, were dated. These trees were burring with sediment and sometimes wounded by transported material and abrupt growth reduction resulted from this process. A local chronology was constructed from 15 living spruce trees growing on Cervena Hora massif to compare tree ring variation of burred and wounded trees and trees growing outside of depositional zone. Secondly exposure of 15 roots were dated. Roots of spruces growing upstream of the dams are exposed as a result of lateral erosion which occurred after reservoirs were entirely filled. Dating of growth reductions and root exposure allows detecting events when the dam reservoirs were filled.

RESULTS AND CONCUSIONS Check dams, which force deposition of mineral and organic material originated from the upper part of the 1 University of Silesia, Faculty of Earth Sciencacetsc, hBmedeznintsk(a s60ob, 4s1e-200rvedSofrsnoomwi ecth,ePodleanpod s(Titesl.:o+f48th-032e d-e3b8r0i-s 9104; Fax: +48-032-380-9104; email: irekgeof@lowwp).p, la)re located in the medial and lower section of the 2 Uiversity of Wroclaw, Institute of GeographCyearnndyRPegoitooknalsDtreeavemlopcmheannt,n50el-.138ThWe sroycsltaewm, Poofla5nd d(aTmels.: +w48as- 071-375-2233; Fax: +48-071-343-5184 emailbu: piiltotr .o iwnczathree k@ afgteormgr.aunthi. w orofc.capl)tastrophic events, which occurred between 1920 and 1930, These events were comparable to the large floods observed at the end of the 19th and the beginning of the 20th century. The check dams (all < 6 m height) have induced the change of natural fluvial processes and the course of the Cerny Potok stream. Accumulation of sediment occurs upstream of the dams whereas intensive erosion is observed downstream. The dam reservoirs are almost completely filled with 198 to 387 m3 of fluvial deposits. The dam reservoirs were filled in 1948, 1957, 1962, 1967/68, 1972/73, 1979, 1983, 1985/87 and 1997 (Fig. 1). Trees growing on the upper section are about 65 years old, trees in the lower section germinated earlier, in the first decade of 20th century. The trees in the upper part of the study area were probably killed during the extraordinary event of 1921. The oldest episodes were recorded in the lower part of the Cerny Potok stream in 1921 and 1935/36. No intensive morphological transformation episodes occurred between 1936 and 1955. Important events of the dams filling took place between 1956 and 1979 (Fig. 1). Dendrochronological analysis revealed that reservoirs above the check dams Fig. 1: Dendrochronological results are filled within 50 to 60 years. Erosion started derived from Cerny Potok stream downstream after the dams had been built. Intensive lateral erosion occurred in the stream channel as soon as the reservoirs above the check dams were filled.

Keywords:Key words: Check dams, Sediment supply, Big floods, Mountain stream sedimentation, Dendrochronological methods.

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