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abovetheSancereservoirintheUpperOstraviceRiverthreetimesaday(7a.m.,
2p.m.,8p.m.),namelyattheStareHamrygaugingstation.Samplesofwaterfrom
otherriversandstreamsinthecentralandeasternpartoftheMoravskoslezske
BeskydyMts.wereonlytakenonceaday(usuallyaround2p.m.orduringheavy
rainfallorperiodofsnowmelting).Fortheoverallevaluationofthesuspended
loadregime,TheCzechHydrometeorologicalInstituteinOstrava(CHMU)has
provideddataaboutrainfallandsnowmelting,aswellasthoseofwaterdischarge
atselectedsamplingprofileswheretheCHMU’sgaugingstationsarelocated,too.
InordertodeterminetheamountofsuspendedloadwhichhassettledintheSance
andMoravkareservoirs,samplesweretakenalsobelowthereservoirdams.
Inthepost-warperiod,thehydrologicalfunctionoftheMoravskoslezske
BeskydyMts.wasendangeredtosuchanextentthatin1954,itwasproclaimed
astate-levelsignificantwatermanagementregion(resolutionNo.72)anditwas
decidedtoconstructasystemofwaterreservoirs.Itwasinthisperiodthatthe
logginginthewoodsbecamemechanized,whichledtotheintensificationofwater
erosionontheunpavedforestroads.Recordsofthissituationcanbefoundin
anumberofstudies(Beneš,1982;Zeleny,1972,1974,1975,1976;Jařabdč,
1978,1979),manypublishedbytheauthorofthispaper(Buzek,1976,1981,1983,
1985,1989,1990,1993,1996,1997,1999,2001,2004,2007).O.Riedl(1973)
assessestheconditionoftheanti-erosionprotectionschemeintheUpperOstravice
Riverwatershed.V.KrečmerandV.Peřina(1982)elaborateddetailedprin-
ciplesofforestmanagementinthewatershedsoftheBeskydyMts.reservoirs.
V.Zeleny(1972)presentedacomprehensivestudyonsoilerosionwhere,aswell
asV.Šach(1986),hepaysattentiontothedegradationofforestsoilsduetoero-
sion.Thesiltingupofwaterreservoirsisdiscussedinmanystudies,ofwhichthe
authorchosestheCzechones(Riedl,1973;Jičinsky,1975;Krečmer,Peřina,
1976;Buzek,1997;Peřina,Krečmer,Šach,1977)andaninterestingpaper
fromsouthAfrica(Roux,Roos,1982).Someofthefirststudiestodealwiththe
anthropogeniceffectsofforestryandloggingaretheAmericanpaperspublished
inTheJournalofForestry(Frevertetal.,1955;Megahan,1972).
AccordingtoR.Midriak(1977),5110%ofthewoodedareasintheCzech
Republicareaffectedbywatererosion.AstudyoftheLesprojektInstitutein
Frydek-M.stek(Collectiveofauthors,1975)carriedoutintheUpperOstravice
watershedanditstributaries(72.96km2)abovetheSancereservoir,6.2%ofthe
forestroadsontheflyschbedrockaretotallydevastated,38.5%seriouslydamaged
and38.1%slightlydamaged.Thismeansthattheanthropogenicfactors(logging,
workintheforest),apartfromthenaturalones,arenotinsignificantinaffecting
thecourseandintensityofwatererosiononforestsoils.Thehumaninterventionis
especiallyvisibleinplaceswithlarge-area,plannedloggingandonslopeswhere
newforestroadswereconstructed.Insuchareas,theharmfulerosioncanincrease
to90%duetoitsnegativeeffectsonallpartsoftheenvironment.Inthearea
studied,apartfromthetwolargereservoirs,anumberofsmalldams,so-called
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