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IZLAGANJE NA ZNANSTVENOM SKUPU PRESENTATION AT THE INTERNATIONAL SYMPOSIUM Šumarski list SUPLEMENT (2005). 7-16 UDK 630* 116 PEDESET GODINA ŠUMARSKOG HIDRO-PEDOLOŠKOG ISTRAŽIVANJA U ŠUMSKIM BAZENIMA PLANINSKIH VODOTOKA FIFTY YEARS OF FORESTRY HYDRO-PEDOLOGICAL RESEARCH WITHIN THE FOREST BASINS OF MOUNTAIN WATER RUNS Zdenek VICHA* SAŽETAK: Na dan 31. 10. 2003. godine završeno je pedesetogodišnje mjerenje hidroloških i klimatskih podataka u dvama pokusnim bazenima Cervik (CE) i Mala Raztoka (MR) u planinama Beskydy. Istraživanje je imalo za cilj procijeniti odnos između oborina i otjecanja kao elemenata vodne ravnoteže u malim šumskim slivovima. Pokus pokazuje da odnos između oborina i otjecanja u malim šumskim planinskim slivovima ovisi više o prirodnim elementima nego o metodama gospodarenja šumom. Šumska tla važni su elementi u hidrološkom režimu slivova s kvalitetama infiltracije i retencije. Željeli bismo predstaviti učinkovite prijedloge za gospodarenje šumama, koji se mogu zahvaljujući dugotrajnosti istraživanja vezati za, na primjer, ophodnju šume. UVOD - Introduction Mjerenje, vrednovanje i modeliranje odnosa oborieksperimenta. Mjerenje i vrednovanje odnosa oborina i na - otjecanja u šumovitim planinskim slivovima ima otjecanja u malim šumskim bazenima, te utjecaj na podugu tradiciju u mnogim zemljama. U Cehoslovačkoj jedine komponente šumskog gospodarenja osnovni je je već 1928. Mr. Välek započeo šumarsko-hidrolo-cilj toga pokusa. Dugoročno je razdoblje pokusa omoško mjerenje u bazenima Kychovä i Zdechovka u plagućilo bolje razumijevanje međuodnosa te njihovu prininama Javornik. Početkom pedesetih godina prošloga mjenu u šumskom razvoju (npr. razdoblje ophodnje). stoljeća povećalo se zanimanje za gospodarske mjere, Međutim, problem je suviše složen, pa se nedvosmislešto podupiru vodne funkcije. Novi pokusni objekti poni zaključci teško mogu očekivati. Mjerenje treba nasstavljeni su u Moravskoslezske Beskydy. Radi se o slitaviti, a podaci se moraju temeljito analizirati. Moramo vu Mala Räztoka (2,08 km2) i Červik (1,85 km2). Isbolje i detaljnije razumijeti koji su elementi i njihove traživanje započeto 1. studenog 1954. još uvijek traje, promjene/odnosi najvažniji za proces oborina-otjecašto je u svjetskim razmjerima najdulje trajanje nekog nja u šumskim sastojinama. POKUSNI SLIVOVI CE I MR - Experimental basms of CE and MR Eksperimentalni sliv CE smješten je u Zadni hory istraživanja primijenjena je metoda dvaju bazena. NaMoravskoslezske Beskydy, iznad vodnog rezervoara kon 1965, dio A je brzo pošumljen sječom u prugama, Šance, na visini 640-960 m iznad morske razine. Baa dio B ostavljen je kao kontrola, bez namjerne sječe, zeni su 100 % pod šumom, u procjeni predstavljeni s te s prirodnom obnovom. 85 % četinjača. Bazen je prirodno podijeljen u dva Pokusni bazen MR nalazi se na sjeverozapadnim padijela, CA (0,88 % km2) i CB (0,84 km2". U svrhu dinama Beskyda, na visini 602 m - 1084 m iznad mora. Između 1953. i 1965. predviđen je bez sastojinske ob nove, a od 1966. sastojina je obnovljena sječom u pru gama. Tijekom obnove u MR bukva je zamijenjena * Ing. Zdenek Vicha, UJLHM Jilovište - Strnady, smrekom, a razlike u otjecanju su bilježene. Detaljne Ured Frydck - Mistek, Nadražni 2811, CZ - 738 01, karakteristike dvaju bazena predstavljene su u Tablici. e-mail frydek.vulhm@mybox.cz |
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Z. Vicha: PEDESET GODINA ŠUMARSKOG H1DRO-PEDOLOSKOG ISTRAŽIVANJA U ŠUMSKIM Šumarski list SUPLEMENT (2005), 7-16 METODA ISTRAŽIVANJA UNUTAR DVAJU BAZENA Metod of research within the two basins Istraživanje u bazenima MR i CE temelje se na vrednovanju šumsko-gospodarstvenih mjera s obzirom na otjecanje i vodnu ravnotežu. Uzimaju se u obzir osnovno stanje šume, orografski i sastojinski uvjeti, različiti za dva bazena. Ukupni posječeni volumen u dva bazena (Tablice 1, 2) pokazuju, daje sječa bila intenzivno motivirana s ciljevima istraživanja krajem sedamdesetih godina. U osamdesetim godinama, nakon teške štete zračnim zagađenjem, uglavnom na izloženim padinama i grebenskom dijelu bazena MR, sječa je gotovo stala. Brza obnova u bazenu CE također je zaustavljena, te je ograničena samo na najvažnije šumarske mjere, unatoč činjenici da šteta uzrokovana zračnim zagađenjem nije bila tako teška u ovom bazenu. Međutim, to nije utjecalo na cilj istraživanja, jer je obnova bila u takvom stanju da su rezultati obnove mogli utjecati na otjecanje. Tablica 1. Karakteristike pokusnih bazena Table 1 Characteristics of experimental basins Osnovna geografska obilježja -Coordinates Sj. zemljopisna širina -North latitude Površina u km" -Area Nadmorska visina od m -Altitude do m Srednja nadmorska visina um - Mean alt. Inklinacija -Incline Ekspozicija glavnih vodotoka -Prevailing water run expositionDužina vodotoka - Lenght of the water run Nadmorska visina izvora - Source alt. Inklinacija vodotoka u % - Incline of the water run Sumovitost bazena u % -Forestation of the basin Geološka podloga -Mother rock Mehanički tip tla -Mechanical soil type Zastupljenost vrste u % - Tree species representation Smreka -Spruce Jela -Fir Bukva -Beech Ostale listače -Other broadleaves U oba pokusna bazena karakteristike oborina i otjecanja, jednako kao i ostale meteorološke vrijednosti, mjere se klasičnim metodama, nedavno izrađenim digitalnim metodama mjerenja. Na taj je način informativna vrijednost podataka poboljšana, uglavnom za ekstremne hidrološke situacije. Ipak, klasične metode su još uvijek važan izvor podataka, te se mogu rabiti za dopunjavanje ili ispravljanje digitalno mjerenih podataka, a isto tako pomažu u slučaju kvara digitalne opreme. Za mjerenje meteoroloških vrijednosti, instalirane su meteo-stanice unutar slivova, te ih promatrači dnevno kontroliraju. Stanice su opremljene klasičnom kutijom s normalnim termometrom, vlažnim termometrom, i termometrom za mjerenje maksimalnih i minimalnih temperatura. Također se bilježi duljina trajanja sunčane svjetlosti. Červi´k 18°23´ 49° 27´ 1,85 640 960 800 30 Sjeveroistok/M:. 1945 900 13.9 100 Pješčanik/ Godulic sand-stone škriljevci/.vtae pijesak-glinaAvanJ-c/ay ilovača//oa/mV 74,7 0,3 24,6 0,4 Zastupljenost vrsta po volumenu u % - Species representation by volume Smreka Spruce 93,8 Jela -Fir 0,5 Bukva Beech 5,6 Ostale listače -Other broadleaves 0,1 Prosječna starost - A verage age 47 Drvna zaliha po 1 ha u m Timber supply 233 Prosječna godišnja temperatura °C - Average year temperature 6,2 Pros. god. količina oborina u mm - Average year precipitation 1122,4 Mala Räztoka 18° 15´ 49° 30´ 2,076 602 1084 840 50 Sjeverozapad/AW. 2000 962 22,8 100 Pješčanik/ Godulic sand-stone ilovasti pijesak/ loam i sand 56,4 0 35,8 7,8 35,8 0,2 59,1 4,9 51 160 6,9 1238,4 |
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Z. Vicha: PEDESET GODINA ŠUMARSKOG IIIDRO-PEDOLOSKOG ISTRAŽIVANJA U ŠUMSKIM Šumarski list - SUPLEMENT (2005), 7-16 Mjerenje oborina je važno, radi se s više detalja nego rutinski u klimatologiji. U svakom je slivu instalirano četiri totalizera, tri na vodnoj granici, jedan u dolini, u središtu bazena. Ukupne oborine mjere se mjesečno. Oborine se bilježe pluvijalnim grafikonima tjedno, s važnim podacima o poplavama i njihovom analizom. Mjerači oborina u stanici verificiraju pouzdanost mjerenja. Zimi se mjeri sloj novog snijega, ukupni sniježni pokrov i njegova vodna vrijednost. Mjesečne ukupne oborine slivova izračunavaju se primjenom poligonske metode Horton-Thiesson. Vodno se otjecanje mjeri u betonskim mjernim lijevcima s limnigrafskim šahtom. Ovi su opremljeni s limnigrafima OTT tjednog režima. Promatrači dnevno mjere razinu vode i temperaturu. Otjecanje se vrednuje na temelju potrošnih krivulja, a vrijednosti se opetovano verificiraju. Minimalni protok mjeri se u 50-litarskom kalibriranom kontejneru, ispod žice lijevaka. Tri lijevka u slivu CE mjere nezavisno otjecanje dvaju dijelova bazena, a također i otjecanje niz pritoku. Detaljniji podaci o digitalnom mjerenju: Registracijski blok M4016 sa 16 kanala opremljen s akumulatorom osnova je opservacijske stanice MS 16. Registracijski blok omogućuje povezivanje svih standardnih tipova mjernih senzora. Svi uobičajeni senzori sa standardnom, tekućom frekvencijom ili pulsnim outputom mogu se priključiti na blok. Nekoliko ultrasoničnih i clektrokemijskih pokusa s digitalnim outputom mogu se na taj način priključiti na blok. Povezanost s blokom izvodi se s programima MOST, te aktualnom verzijom MOST 32. Programi prenose podatke u radnu knjigu, konstatiraju parametre mjerenja, poh rane podataka i obrade podataka uz uporabu outputa iz tablica i grafikona. Za mjerenje razine vode u otvorenim lijevcima, primijenjuju se ultrasonične probe US 3000. Mikroprocesor izračunava razdaljinu na temelju vremenskog intervala poslanog ultrasoničnog impulsa i njegovog odraza, korigiranog na temelju temperature zraka. Bazna rezolucija probe je 1 mm. Zračna temperatura mjeri se termometrom platinske rezistencije Pt 100 s tekućim prijenosnikom u gla vi. Za mjerenje kapaciteta zračne vlage rabi se senzor s tekućim outputom. Termometer i senzor vlage zaštićeni su radijacijskim pokrovom, a postavljeni su na jarbol visine 2 m iznad tla. Temperatura zraka također se mjeri platinskim termometrom Pt 100. Čitav kompleks priključen je na pulsni input registracijskog bloka. Ovaj registrira, u jednom od kanala, volumen oborina unutar vremenskog razdoblja postavljenog intervala pohrane podataka u bloku. Načelo uporabe mjerača oborina temelji se na mehanizmu čamca (dumping boat) podijeljenom u dva dijela, kako bi se dobili električni impulsi, ovisno o intenzitetu oborina. Kiša prolazi kroz otvor strogo određenog područja, izravno u lijevak, te nastavlja do gornjeg dijela čamca. Kada se gornji dio napuni određenom masom oborine, čamac se prevrne. Polovina čamca se isprazni, a druga polovina dospije pod lijevak. Ovaj se proces nastavlja do prestanka kiše. Magnet pričvršćen na tijelo čamca dovodi do kontakta pri svakom prevrtanju. Ovaj kontakt, ovisno o protoku oborine, omogućava registriranje broja prevrtanja, a time i volumen oborine. REZULTATI DUGOROČNOG ISTRAŽIVANJA U PLANINAMA BESKYDY Results of long-term research in Beskydy Mts. Tijekom čitavog razdoblja istraživanja u bazenu CE, prosječna godišja oborina bila je 1122,4 mm, otjecanje 646,2 mm, prosječan godišnji protok bio je 20,5 1. s"´x km2. U bazenu MR prosječna godišnja oborina bila je 1.238,4mm, otjecanje 912 mm, prosječan godišnji protok 28,9 1 s" -1 x km2. U grafikonima su prikazane prosječne mjesečne oborine i otjecanje u razdoblju 1954 - 2003. U Beskydima snijeg se topi od ožujka do svibnja, a najviše oborina padne za vrijeme ljetnih mjeseci. Detaljna analiza vodne ravnoteže u šumskim sastojinama vrlo je složen prirodni proces. Počinje mjerenjem pojedinih kiša, broja dana među njima, intercepcije, evapotranspiracije, natapanja vode u tlu, otjecanja pod različitim klimatskim uvjetima, sezone i prirodnih uvjeta. Pri jakoj kiši dio se vode natopi u šumskom tlu, manji dio otječe, uglavnom u zemljišta nabijene i stabilizirane površine. Volumen vode upijen u šumskom tlu ograničen je. To je razlog što se površinsko otjecanje može promatrati kada je voda koncentrirana u rovovima i vodotokovima. Ovaj tip otjecanja ima udjel od 15-20 % ukupne maksimalne količine, i ograničenje na vrlo kratko vrijeme. Veći postotak je onaj brzog površinskog otjecanja u poplavnim valovima; retencijski kapacitet tijekom čitavog razdoblja jedva je prelazio 2mm u minuti, što znači 33 m3 vode po kvadratnom kilometru u sekundi. Najveće specifično otjecanje bilo je izmjereno u MR : q = 3.144m3 x s" . km". Ovi podaci podvrđuju brzu vodnu retenciju šumskog tla. Zaista velike, iznenadne kiše u Beskydima rezultirale su poplavama. Opasne su i vodne kulminacije što prelaze 1000 . s"1 x km2. Za vrijeme istraživanja, takvi su događaji primijećeni devet puta u MR i sedam puta u CE. U MR je najviša kulminacija zabilježena nakon bujice izazvane kišom 25. srpnja 1966 s već spomenutom vrijednosti od 3.144 1 s~´ x km2. U CE je najveća |
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Z. Vicha: PEDESET GODINA ŠUMARSKOG HIDRO-PEDOLOŠKOG ISTRAŽIVANJA U ŠUMSKIM Šumarski list - SUPLEMENT (2005), 7-16 Slika 1. Červik-sječa (nv) Figure 1 Červik - timber felling (m ) Slika 2. Mala Raztoka-sječa (m3) Figure 2 Mala Raztoka - timber felling (m ) kulminacija bila 1. kolovoza 1971. : 1.576,2 1 x s ´ x km2. Ustanovljeno je da su za kulminaciju odlučni razina i intenzitet danih oborina. Nakon obnove zrelih sastojina, povećani protok broja kulminacija nije dokazan statistički. U teškim poplavama grane i drveće također teku niz vodenu struju. Pritom su brane, mostovi i čitava riječna i potočna korita napunjena takvim materijalom, a voda izlazi preko obala, pa okolno zemljište može biti oštećeno. Vrednovanje malih i minimalnih vodotokova tijekom suhog razdoblja godine također je korisno. Mjerenje je dokazalo da su takva razdoblja češća od poplava, ovisno o temperaturi zraka. Ona traju najviše nekoliko dana. Ta razdoblja su dulja zimi, čak po dva mjeseca. Tijekom 50-godišnjeg mjerenja minimalna su otjecanja iznosila do qmin<0,5 1 . s"´x km2, ugrožavajući ne samo vodni biosustav, nego i vodne rezervoare u selima podno planina. |
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Z. Vicha: PEDESET GODINA ŠUMARSKOG HIDRO-PEDOLOŠKOG ISTRAŽIVANJA U ŠUMSKIM Šumarski list - SUPLEMENT (2005), 7-16 XI XII I II III IV V VI VII VIII IX X mjesec -month Slika 4. Červik - prosječne mjesečne oborine i otjecanje 1954 - 2003. Figure 4 Červik -average monthly precipitation and run-off in 1954 -2003 Hs DHo XI XII I II III IV V VI VII VIII IX X mjesec -month Slika 3. MaläRäztoka- prosječne mjesečne oborine i otjecanje 1954-2003. Figure 3 Mala Räztoka -average monthly precipitation and run-off in 1954 -2003 Kao što je več rečeno, u bazenu CE istraživanje ima druge prednosti, također za vodni režim. Šumsko otjecanja izvedeno je unutar dva bazena. Fokus je bio tlo ne erodira uslijed oštećenja teškom mehanizacijom, na pitanju: jesu li različiti načini gospodarenja i s time infiltracijska sposobnost tla nije narušena, pa otjecanje povezane različite dobne strukture sastojina utjecali na vode ispod površine nije narušeno. I površine golog režim otjecanja? Vrednovanje rezultata dugoročnog iszemljišta nakon velikih kiša nisu ugrožene erozijom. traživanja dovodi do zaključka da nisu opažene dokaTo je uglavnom problem slabih površina s nedovoljnim zive promjene uvjeta otjecanja. Šumska obnova nije vegetacijskim pokrovom, gdje tlo nije pokriveno trabila povezana s redukcijom otjecane vode, a preostale vom i korovom. Predmetne površine u Beskydima umstarije sastojine s većom drvnom zalihom nisu pokazajereno su bogata zemljišta, a nakon sječe tlo je pokrivele veće otjecanje. Međutim, mora se naglasiti da unano travom već nakon nekoliko tjedana, što štiti protiv toč činjenici da nisu opažene signifikantne promjene u erozije. Unatoč činjenici da negativni utjecaji čiste režimu otjecanja u sastojini gospodarenoj intenzivnom sječe u razmjerima dozvoljenim zakonom nisu dokazačistom sječom, blaže, prirodi prikladnije gospodarenje ni pri otjecanju vode, treba naglasiti ostale prednosti |
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Z. Vicha: PEDESET GODINA ŠUMARSKOG HIDRO-PEDOLOŠKOG ISTRAŽIVANJA U ŠUMSKIM ... Šumarski list - SUPLEMENT (2005), 7-16 ekološkog gospodarenja. To su uglavnom očuvanje bioraznolikosti, veća stabilnost ekosustava, očuvanje genetski vrijednog materijala autohtonih sastojina, te veća estetska i rekreacijska vrijednost šuma. Važnije promjene u uvjetima otjecanja primijećene su u bazenu MR, gdje je glavna vrsta drveća, bukva, zamijenjena smrekom u procesu obnove. Tijekom godina niskih oborina, otjecanje vode je tamo bilo veće. To znači da je u toplim razdobljima godine otjecanje bilo veće, a u hladnim je veće u godinama velikih obo ZAKLJUČAK I PRAK Conclusion and practi Prirodni retencijski kapacitet šuma je ograničen. Pod najintenzivnijim oborinama čak i prirodne šumske sastojine nisu u stanju spriječiti poplavu. U šumskim gospodarenjima preporučuje se stvoriti odgovarajući sastav vrsta i uravnotežen dobni sastav. U šumskoj obnovi važno je stabilizirati nove kulture na vrijeme, te očuvati odgovarajuće kvalitete šumskog tla s visokim kapacitetom infiltracije. U šumskoj njezi treba podržavati uglavnom otpornost mladih sastojina protiv štete od biotskih i abiotskih uzročnika, kako bi se spriječilo njihovo narušavanje i očuvao njihov kapacitet pozitivnog utjecaja na hidrološki režim. Dobro planirane šumske ceste i tehnološke linije trebaju uzimati u obzir otjecanje nagomi- LITERATURA Biba, M. et ah, 2001: Vliv hospodareni v lesich na tvorbu odtoku a kvality vody v zalesnenych po vodich v kontextu komplexni protipovodfiove ochrany krajiny. Zäverecnä zpräva projektu EP 9090, VÜLHM Jilovište - Strnady. Biba, M, A. Chlebek, M. Jarabač, J. Jirik, 2001: Les a voda - 45 let trväni vodohospodär skeho vyzkumu v Beskydech. Zpr. Lesn. Vyzk., 46: 231-238, ISSN 0322-9688. rina. Topljenje snijega uglavnom uzrokuje veliko otjecanje u hladnim razdobljima, bogatijim oborinama nakon obnove sastojina više vode otječe. Može se reći, daje zamjena bukve smrekom od velike važnosti, s obzirom na otjecanje vode, nego različiti načini gospodarenja. Evapotranspiracija je snižena, najvjerojatnije zbog niskog kapaciteta piitkijeg korjenskog sustava smreke, s obzirom na uporabu oborinske vode infiltrirane u dubljim horizontima, što rezultira povećanim minimalnim otjecanjem. riCNE PREPORUKE ;al recommendations lane oborinske vode u tim horizontalnim objektima. Važna je i kontrola bujica izvedena na pravilan ekološki način. Cilj je spriječiti eroziju koja pogoršava utjecaj poplavnog vala u donjim dijelovim vodotokova. Sastojine blizu vode trebaju se održavati, a vrste jakog korjenskog sustava što fiksiraju riječne obale i odupiru se ekstremnim vodama treba održavati. Jasno je da takav blag pristup može biti lakše osiguran gospodarenjem na malim površinama na ekološki način. S gledišta važnijih šumskih funkcija, takvo gospodarenje ima mnoge druge prednosti, uglavnom u područjima izvora i planinskih vodotokova. - References Biba, M., A. Chlebek, M. Jarabač, J. Jirik, 2002: Lesnicko.hydrologicky vyzkum v Besky däch v roče 2001, Beskydy, MZLU v Brnc, 15: 25-30. Biba, M., M. Jarabač, Z. Vicha, 2003: Minimalni odtoky z Beskydskych experimentälnich povodi v letech 1954 až 2003, Beskydy, MZLU v Brne, 17:23-28. |
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PRESENTATION AT THE INTERNATIONAL SYMPOSIUM Šumarski list SUPLF.MENT (2005), 7-16 FIFTY YEARS OF FORESTRY HYDRO-PEDOLOGICAL RESEARCH WITHIN THE FOREST BASINS OF MOUNTAIN WATER RUNS Zdenek VICHA* SUMMARY: After a period offiftyyears, measurements of hydrological and climatic data in two experimental basins of Cervik (CE) and Mala Rdztoka (MR) were completed on 31 October 2003. The goal of research was to evaluate the relationship between rainfall and outflow as elements of water balance in small forested watersheds. According to the experiment, the relationship between precipitation and outflows in small forested mountain watersheds depends more on natural elements than on methods of forest management. In terms of infiltration and retention quality, forest soils are very important elements in a watershed hydrological regime. We would like to present efficient suggestions for forest management obtained from long-lasting research, which can be related to the rotation cycle of a forest, for example. INTRODUCTION Measuring, evaluation and modelling of the precipimany other experiments worldwide. Measuring and tation-run-off relationship in the forested mountain baevaluation of the precipitation - run-off relationship in sins has a long tradition in many countries. In Czechosthe small forested basins, and the impact on individual lovakia forestry-hydrological measuring has been initiacomponents of the forest management is the primary ted already in 1928, by Mr. V ä 1 e k, within the basins of goal of the experiment. Mainly long-term period of the Kychovä and Zdechovka, Javornik Mts. At the begin research had made possible to understand better the ining of fifties of the last century, the interest in the manater- relations, and their application in forest development gement measures, supporting forest water function, was (e.g. rotation period). However, the problem is too comincreased. Thanks to Marana and Zeleny the new expeplicated, and unambiguous conclusions can be hardly rimental objects have been installed in Moravskoslezske expected. Measuring has to go on and the data are to be Beskydy (Moravian-Silesian part of the Beskydy Moundeeply analysed. We need better, in more detail, understains). It is the basin of Mala Räztoka (MR - 2.08 km2) tand which elements and their changes and relations, are and Červik (CE - 1.85 km2). Research, initiated there in the most important for the precipitation-run-off process November 1, 1954, is still on going, the time exceeding in forest stands. EXPERIMENTAL BASINS OF CE AND MR The experimental basin of CE is situated in so calresearch purpose, the method of the pair basins was led Zadni hory (Back-side Mts.) of Moravskoslezske used. After 1965, part A was fastly reforested by the Beskydy, over the water reservoir Šance, at the altitude strip cutting, part B was left as a control, with no intenof 640 - 960 m over the sea level. The basin is 100 % tional felling, and natural regeneration. forested, in the term of calibrating 85 % of conifers Experimental basin of MR is situated on the NW was represented. The basin is naturally divided in two slopes of Beskydy, at the altitude of 602-1084 m over parts, called CA (0.88 km2) and CB (0.84 km2). For the sea level. In 1953 - 1965 it was calibrated without stand regeneration, since 1966 the stand was regenera ted by the strip felling. During the regeneration in MR, * Ing. Zdenek Vicha, Forestry and Game Management Research beech was replaced by spruce, and the differences in Institute, Jilovište - Strnady, office Frydek - Mistck, run-off were recorded. Detailed characteristics of the Nadražni2811,CZ-738 01, e-mail frydek.vulhm@mybox.cz two basins are presented in the Table. |
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Z. Vicha: FIFTY YEARS Ol" THE FORESTRY HYDRO-PFDOLOGICAL RESEARCH WITHIN THE FOREST ... Šumarski list - SLJPLEMENT (2005). 7-16 METOD OF RESEARCH WITHIN THE TWO BASINS Research within the basins of MR and CE is based on evaluating of the forest management measures with respect to the run-off, and water balance. Basic forest state, orographic and stand conditions, different in the two basins, are considered. Total volume felled within the two basins (Tabs. 1, 2) shows, that felling was intensively motivated by the research aims by the end of seventies. In eighties, after hard damage by air pollution, mainly in the exposed slope and ridge part of the basin MR, felling was nearly stopped. Fast regeneration in CE basin was also closed, and it was limited only to the most important forestry measures, in spite of the fact that damage by air pollution was not that heavy in this basin. However, the aim of the research was not affected, as the regeneration was in such a state that the run-off could be affected by its results in measurable way. In both experimental basins the precipitation and run-off characteristics, same as other meteorological values, are measured by classic methods, newly completed by digital methods of measuring. Thus the informative value of the data was improved, mainly for the extreme hydrological situations. Nevertheless, the classic methods are still important data source, and they can be used to complete or correct the data measured digitally, and they also help in case of the digital equipment failure. To measure meteorological values, meteo-stations have been installed within the basins, controlled daily by the observers. The stations are equipped by classic case with normal thermometer, wet thermometer, and thermometer for measuring of maximum and minimum temperature. Also the length of sunshine is recorded. Measuring of precipitation is of importance, done in more detail than the routine in climatology. In each basin four totalisers are installed, three of them in water divide, one in the valley, in centre of the basin. Total precipitation is measured on monthly base. Precipitations in time are recorded by pluvial-graphs on weekly base, giving important data on floods and their analyzing. The station precipitation meters verify reliability of measuring. In winter the layer of new snow is measured, total snow cover and its water value. Monthly total precipitation of the basins is calculated using the polygon method by Horton-Thiesson. Water run-off is measured in the concrete measuring funnels with limnigraphic manhole (shaft). They are equipped with limnigraphs OTT of week regime. Water level on the scale, and water temperature are measured daily by the observer. Run-off is evaluated on the base of consumption curves, the values are verified repeatedly. Minimal flow is measured in 50 litre calibrated container, under the wire of funnels. There are three funnels in the CE basin, measuring independently run-off of the two parts of the basin, and also run-off down the confluence. More detailed information on digital measuring: The 16-channel registration unit M4016, supplied by accumulator, is the base of the monitoring station MS 16. The registration unit makes possible to connect all types of measuring sensors of standard. All common sensors with standard, current, frequency or pulse output can be connected to the unit. A number of ultrasonic and electrochemical probes with digital output can thus be connected to the unit, of digital output of data measured. Communication to the unit is done by the MOST programmes, and the actualised version of MOST 32, respective. The programmes transfer the data to the notebook, state the parameters of data measuring and storing, and data processing, using table and graph outputs. To measure water level in the open funnels, the ultra- sound probes are used, US 3000. Microprocessor in it is calculating the distance on the base of the time interval of the ultra-sound impulse sent and its reflection, corrected on the base of air temperature. Basic resolution of the probe is 1 mm. Air temperature is measured by platinum resistance thermometer Pt 100 with a flow transferor in the in the head. To measure absolute air moisture capacity sensor with flow output is used. Thermometer ans moisture sensor are protected by radiation cover, and they are placed in the mast, in a height of 2 m above soil surface. Water temperature is also measured by platinum thermometer Pt 100. The whole complex is packed in silicone, so it can be placed in water. To measure volume and intensity of precipitation, meters type SR02 are used, of catching area of 200 cm2. Precipitation meter is connected to the pulse input of the registration unit. This registers, in one of the channels, volume of precipitation, within the time period given by the set interval of data storing by the unit. Principle of the use of precipitation meter is based on the mechanism of dumping boat, divided in two parts, to get the electric pulses, depending on precipitation intensity. The rain comes through the opening of strictly given area, directly to a funnel, and it goes to the upper part of a boat. Where the upper part is filled by adjustable volume of precipitation, the boat dumps. This half of the boat is empted, and the other half gets under the funnel. This process is on going by the end of rain. Magnet, fixed in the boat body, in each dumping connects the contact, placed in the boat stick. This connection, depending on flow of defined precipitation volume, makes possible to register number of dumps and so precipitation volume. |
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/ . Vicha: FIFTY YEARS OF THE FORESTRY HVDRO-PEDOLOGICAL RESEARCH WITHIN THE FOREST ... Šumarski list SUPLEMENT (2005). 7-16 RESULTS OF LONG-TERM RESEARCH IN BESKYDY MTS. During the whole period of investigation within the CE basin, the average year precipitation was 1122.4 mm, run-off 646.2 mm, average year flow was 20.5 1 x s"´ x km2. In MR basin the average year precipitation was 1238.4 mm, run-off 912.0 mm, average year flow 28.9 1 x s"1 x km2. In the graphs there are average monthly precipitation and run-off in the period of 1954 to 2003. In Beskydy snow is melting in March to May, the highest precipitation is during the summer months. Water balance in the forest stands, hydrologic ally analysed in detail, is very complicated natural process. It starts in measuring of individual rain, number of days in between them, interception, evapotranspiration, soaking of water in soil, run-off under different climatic conditions, season, and natural conditions. In a strong rain, part of water is soaked by the forest soils, smaller part runs-off, mainly in plots of compacted and stabilised soil surface. Volume of water soaked by forest soils is limited. That is why aerial surface run-off can be observed, when water is concentrated in trenches and water runs. This type of water run-off represents about 15-20 % of the total amount in maximum, ant it is limited to very short time. Higher percentage is represented by fast surface run-off in flooding waves; its development depends on saturation of the basin, volume and length of rain, permeability and depth of the soils, slope inclination, and the tendency to concentrate run-off water. Retention capacity of the soil is confirmed also by the data measured in Beskydy research: Rain intensity over the whole period had hardly exceeded 2 mm per minute, it means 33 nr of water per square km per second, however. The highest specific run-off was measured in MR q= 3,144 m3 x s~´ x km2. This data confirm fast water retention by the forest soil. Some really heavy, sudden rains in Beskydy have resulted in fladdings. Also water culminations exceeding 1000 1 x s"´ x km", are of danger. During the investigation such events were observed 9 times in MR, and 7 times in CE. In MR the highest culmination recorded was after the storm-rain in July 25, 1966, it was already mentioned value of 3,144 1 x s"´ x km2. In CE the highest was culmination of August 1, 1971 - 1,576.,2 1 x s"1 x km2. It was found that for the culmination the level and intensity of given precipitation is decisive. After the regeneration of the mature stands increased number of culmination flow was not proved statistically. In heavy fladdings also branches, parts of the trees etc. are flowing down with water stream. Than sluices, bridges, and whole river and stream beds are filled with that material, water gets out of the banks and the land around can be damaged. To evaluate the small and minimal water runs during the dry period of the year is also useful. Measuring has proved, that such periods are repeated during a year more frequently then fladdings, irregularly, depending on air temperature. They arc lasting mostly several days, as usual; the time is longer in winter, even two months. During the 50 years of measuring the minimal run-off was reaching up to qm}n< 0,5 1 x s ´ x km2, endangering not only the water bio-system, but also water reservoirs in the villages in lower part of the mountains. As mentioned above, in the basin of CE investigation of the run-off water was done within the two pair basins. The research was focused on the problem, whether the different ways of management, and connected different age structure of the stands in the two basins, can be reflected by run-off regime. Evaluating the results of long-term investigation, it can be stated that provable change of the run-off conditions was not observed. Forest regeneration was not connected with the reduction of run-off water, and the older stands left, of higher timber supply, did not show higher run-off. However, it is to be stressed, that in spite of the fact that not significant changes in run-off regime were observed in the stand managed by intensive way of clear- cutting, more sensitive, nature close ways of forest management bring also other advantages, also in water regime. Forest soil is not eroded due to damage by heavy logging mechanisation, soil infiltration capacity is not disturbed, so under-surface water run-off is supported. Also area of bare land, and connected soil erosion after heavy rains, is not that big. This is mainly problem of poor sites, of insufficient vegetation cover, where soil is not covered by grass and weed. The two plots in Beskydy are moderately rich sites, and after felling the soil is covered by grass during several weeks, and thus protected against water erosion. In spite of the fact that negative impact of clear cutting, within the extent given by the law, on water run-off was not proved, other advantages of the nature close management have to be stressed. It is mainly bio-diversity preservation, higher stability of the ecosystem, preservation of genetically valuable material of autochthonous stands, and also higher esthetical and recreation value of forests. More important changes in run-off conditions were observed in the MR basin, where the main tree species beech was replaced by spruce in the regeneration process. During the years of low precipitation, water runoff was higher there. It means that in the warm period of the year water run-off is higher, in the cold period runoff is higher in the years of higher precipitation. Mainly melting snow causes higher run-off in the cold period, richer in precipitation- after stand regeneration more water of it runs-off. It can be said that change of spruce |
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Z. Vicha: FIFTY YEARS OF THF FORESTRY IIYDRO-PFDOFOGICAL RESEARCH WITHIN THE FOREST ... Šumarski list SUPLF.MF.NT (2005). 7-16 for beech is of higher importance, with respect to water lower capacity of more flat root system of spruce, to use run-off, than the different ways of forest management. the precipitation water infiltrated to deeper horizons, Evapotranspiration was lowered, most probably due to which resulted in increased minimal run-off. CONCLUSION AND PRACTICAL RECOMMENDATIONS Natural retention capacity of forests is limited. Under the most intensive precipitation even natural forest stand is not capable to prevent flooding. In forest management it is recommended to create suitable species composition and balanced age composition. In forest regeneration it is important to stabilize the new cultures in time, and to preserve suitable qualities of the forest soil of high infiltration capacity. In forest tending mainly the resistance of the young stands against damage by biotic and a biotic agents is to be supported, to prevent their disturbing and preserve their capacity of positive impact on hydrological regime. Well-planned forest roads and technological lines have to respect sa ve run-off of cumulated precipitation water of these horizontal objects. Also torrent control, done in proper, nature close way, is of importance. The aim is to prevent erosion, which is than worsening the impact of flood wave in the lower parts of the water run. Streamside stands have to be well kept, and the species of strong root system, fixing the riverbanks and resistant in culmination flows are to be supported. It is clear that such a sensitive approach can be more easily ensured in the small-extent, nature close forest management. From the viewpoint of other important forest functions such management has many other advantages, mainly in the spring area of mountain water runs. |