{"id":7596,"date":"2020-02-26T10:31:19","date_gmt":"2020-02-26T09:31:19","guid":{"rendered":"https:\/\/www.vtei.cz\/?p=7596"},"modified":"2024-07-17T09:52:21","modified_gmt":"2024-07-17T08:52:21","slug":"the-dams-of-historical-ponds-in-terms-of-shape-and-stability","status":"publish","type":"post","link":"https:\/\/www.vtei.cz\/en\/2020\/02\/the-dams-of-historical-ponds-in-terms-of-shape-and-stability\/","title":{"rendered":"The dams of historical ponds in terms of shape and stability"},"content":{"rendered":"

<\/i> This article is available in Czech only. For translation or more information on this topic, please contact author.<\/h4>\n

 <\/p>\n

Souhrn<\/h2>\n

\u010cl\u00e1nek p\u0159edstavuje v\u00fdsledky hodnocen\u00ed tvaru hr\u00e1z\u00ed rybn\u00edk\u016f v\u00a0oblasti Kostelecka a\u00a0Kou\u0159imska ve St\u0159edo\u010desk\u00e9m kraji. Tvar hr\u00e1z\u00ed byl posuzov\u00e1n na z\u00e1klad\u011b podrobn\u00e9ho digit\u00e1ln\u00edho modelu ter\u00e9nu zalo\u017een\u00e9ho na datech Digit\u00e1ln\u00edho modelu reli\u00e9fu 5.\u00a0generace. Hodnocen\u00ed bylo provedeno pro celkem 30 hr\u00e1z\u00ed v\u00a0z\u00e1jmov\u00e9m \u00fazem\u00ed. Z\u00a0v\u00fdsledk\u016f proveden\u00fdch anal\u00fdz vypl\u00fdv\u00e1, \u017ee \u0159ada hr\u00e1z\u00ed m\u00e1 hr\u00e1ze se svahy strm\u011bj\u0161\u00edmi, ne\u017e doporu\u010duje pro homogenn\u00ed hr\u00e1ze v\u00a0sou\u010dasnosti platn\u00e1 norma \u010cSN\u00a075\u00a02410. V\u00a0n\u011bkter\u00fdch p\u0159\u00edpadech jsou oproti norm\u011b strm\u011bj\u0161\u00ed oba svahy, n\u00e1vodn\u00ed i\u00a0vzdu\u0161n\u00ed, v\u00a0n\u011bkter\u00fdch p\u0159\u00edpadech pouze jeden z\u00a0nich. Na vybran\u00e9 hr\u00e1zi Podbe\u010dv\u00e1rsk\u00e9ho rybn\u00edka bylo n\u00e1sledn\u011b provedeno posouzen\u00ed stability s\u00a0vyu\u017eit\u00edm modelu SSAP. V\u00fdsledky hodnocen\u00ed stability ukazuj\u00ed, \u017ee dan\u00e1 hr\u00e1z nedosahuje po\u017eadovan\u00e9ho stupn\u011b stability dan\u00e9ho normou \u010cSN\u00a075\u00a02410, by\u0165 to samoz\u0159ejm\u011b neznamen\u00e1, \u017ee by byla akutn\u011b ohro\u017eena. Prezentovan\u00fd postup p\u0159edstavuje mo\u017enost, jak p\u0159istupovat k\u00a0hodnocen\u00ed bezpe\u010dnosti hr\u00e1z\u00ed mal\u00fdch vodn\u00edch n\u00e1dr\u017e\u00ed v\u00a0rozs\u00e1hlej\u0161\u00edch \u00fazem\u00edch za \u00fa\u010delem identifikace potenci\u00e1ln\u00edho nebezpe\u010d\u00ed souvisej\u00edc\u00edho se sn\u00ed\u017eenou stabilitou t\u011bchto zemn\u00edch t\u011bles.<\/p>\n

\u00davod<\/h2>\n

Historie rybn\u00edk\u016f na \u00fazem\u00ed sou\u010dasn\u00e9 \u010cesk\u00e9 republiky je v\u00edce ne\u017e tis\u00edcilet\u00e1. Jako prvn\u00ed doklad o\u00a0existenci stavby, kterou je mo\u017eno ozna\u010dovat za rybn\u00edk, je existence osady Rybn\u00ed\u010dek, kter\u00e1 existovala ji\u017e v\u00a0roce 993 v\u00a0prostoru mezi dne\u0161n\u00edmi ulicemi Je\u010dn\u00e1 a\u00a0\u017ditn\u00e1 v\u00a0Praze na Nov\u00e9m M\u011bst\u011b [1]. Zde byla archeologick\u00fdm v\u00fdzkumem v\u00a0roce 1998 odhalena mal\u00e1 n\u00e1dr\u017e o\u00a0rozm\u011brech 6\u00a0x\u00a012\u00a0m, lze v\u0161ak p\u0159edpokl\u00e1dat, \u017ee tato n\u00e1dr\u017e sp\u00ed\u0161e vyu\u017e\u00edvala k\u00a0zadr\u017een\u00ed vody konfigurace ter\u00e9nu a\u00a0jeho men\u0161\u00edch \u00faprav, ne\u017e aby m\u011bla klasickou hr\u00e1z a\u00a0objekty, jak je zn\u00e1me dnes. Za prvn\u00ed p\u00edsemnou zm\u00ednku o\u00a0existenci rybn\u00edka je pak pova\u017eov\u00e1n dodatek Mnicha s\u00e1zavsk\u00e9ho ke Kosmov\u011b kronice o\u00a0zalo\u017een\u00ed S\u00e1zavsk\u00e9ho kl\u00e1\u0161tera, v\u00a0n\u011bm\u017e je uvedeno, \u017ee kn\u00ed\u017ee B\u0159etislav \u201ez\u00a0vlastn\u00ed \u0161t\u011bdrosti odevzdal (kl\u00e1\u0161teru, pozn. aut.) okoln\u00ed zemi a\u017e k\u00a0lesu Strnovn\u00edku, t\u00e9\u017e ves Skramn\u00edky, jeden rybn\u00edk a\u00a0slup k\u00a0loven\u00ed ryb\u2026\u201c [2]. Obecn\u011b jsou v\u011bt\u0161inou autor\u016f po\u010d\u00e1tky budov\u00e1n\u00ed rybn\u00edk\u016f datov\u00e1ny do obdob\u00ed 9. a\u017e 12. stolet\u00ed [3, 4]. Doklady z\u00a0tohoto obdob\u00ed jsou velmi omezen\u00e9, lze v\u0161ak p\u0159edpokl\u00e1dat, \u017ee zakl\u00e1dan\u00e9 rybn\u00edky byly zpravidla ojedin\u011bl\u00e9 a\u00a0m\u011bly pom\u011brn\u011b n\u00edzk\u00e9 hr\u00e1ze. Masivn\u011bj\u0161\u00ed budov\u00e1n\u00ed rybn\u00edk\u016f spad\u00e1 do obdob\u00ed vl\u00e1dy Karla IV., zejm\u00e9na pak ov\u0161em do obdob\u00ed tzv. zlat\u00e9ho v\u011bku rybnik\u00e1\u0159stv\u00ed, kter\u00fd je obvykle vymezov\u00e1n jako perioda mezi husitsk\u00fdmi v\u00e1lkami a\u00a0v\u00e1lkou t\u0159icetiletou, konkr\u00e9tn\u011bji jako posledn\u00ed \u010dtvrtina 15. stolet\u00ed a\u00a0cel\u00e9 16. stolet\u00ed [5, 6].<\/p>\n

Stejn\u011b jako ostatn\u00ed obory i\u00a0rybnik\u00e1\u0159sk\u00e9 stavitelstv\u00ed pro\u0161lo po dobu sv\u00e9 existence v\u00fdvojem, kter\u00fd se projevil v\u00a0\u0159ad\u011b aspekt\u016f. Jedn\u00edm z\u00a0t\u011bch hlavn\u00edch je tvar hr\u00e1ze, kter\u00fd byl historicky jin\u00fd ne\u017e v\u00a0sou\u010dasnosti. Rozd\u00edl spo\u010d\u00edv\u00e1 p\u0159edev\u0161\u00edm ve sklonech svah\u016f historick\u00fdch hr\u00e1z\u00ed, kter\u00e9 byly obecn\u011b prud\u0161\u00ed ne\u017e ty, kter\u00e9 jsou doporu\u010dov\u00e1ny sou\u010dasn\u00fdmi normativn\u00edmi p\u0159edpisy. Z\u00a0nejstar\u0161\u00edho technologick\u00e9ho p\u0159edpisu zahrnuj\u00edc\u00edho i\u00a0technologii v\u00fdstavby hr\u00e1ze sepsan\u00e9ho olomouck\u00fdm biskupem Janem Sk\u00e1lou z\u00a0Doubravy (Jan Dubravius) pod n\u00e1zvem De Piscinis (O\u00a0rybn\u00edc\u00edch) [3] vypl\u00fdv\u00e1, \u017ee doporu\u010den\u00fd sklon n\u00e1vodn\u00edho i\u00a0vzdu\u0161n\u00edho l\u00edce \u010din\u00ed 1\u00a0:\u00a01, zat\u00edmco sou\u010dasn\u00e1 norma \u010cSN\u00a075\u00a02410 Mal\u00e9 vodn\u00ed n\u00e1dr\u017ee [7] doporu\u010duje u\u00a0zemin vhodn\u00fdch pro budov\u00e1n\u00ed homogenn\u00edch hr\u00e1z\u00ed sklony minim\u00e1ln\u011b 1\u00a0:\u00a02 na vzdu\u0161n\u00edm l\u00edci a\u00a01\u00a0:\u00a03. Mimo technologick\u00fd aspekt lze za v\u00fdznamn\u00e9 pokl\u00e1dat i\u00a0to, \u017ee rybn\u00edky byly historicky budov\u00e1ny v\u00a0kask\u00e1d\u00e1ch, co\u017e umo\u017e\u0148ovalo lep\u0161\u00ed hospoda\u0159en\u00ed s\u00a0vodou v\u00a0nich. V\u00a0t\u00e9 dob\u011b to bylo samoz\u0159ejm\u011b mnohem snadn\u011bj\u0161\u00ed vzhledem k\u00a0majetkov\u00fdm vztah\u016fm k\u00a0p\u016fd\u011b, kdy nebyly vlastnick\u00e9 pom\u011bry tak rozt\u0159\u00ed\u0161t\u011bn\u00e9 jako v\u00a0sou\u010dasnosti a\u00a0zejm\u00e9na \u0161lechta m\u011bla v\u00a0dr\u017een\u00ed dostatek p\u016fdy pro budov\u00e1n\u00ed takov\u00fdchto syst\u00e9m\u016f. Kask\u00e1dy rybn\u00edk\u016f ov\u0161em skr\u00fdvaj\u00ed jedno podstatn\u00e9 riziko, a\u00a0t\u00edm je vznik dominov\u00e9ho efektu p\u0159i protr\u017een\u00ed hr\u00e1ze jednoho z\u00a0v\u00fd\u0161e polo\u017een\u00fdch rybn\u00edk\u016f [8].<\/p>\n\"\"<\/a>\n

Obr. 1. Mapa z\u00e1jmov\u00e9 oblasti s\u00a0vyzna\u010den\u00edm polohy rybn\u00edk\u016f posuzovan\u00fdch s\u00a0ohledem na tvar jejich hr\u00e1ze
\nFig. 1. Map of the investigated area with the location of fishponds evaluated from the point of view of the shape of the dam body<\/h6>\n

V\u00fdzkumn\u00fd projekt NAKI\u00a0II\u00a0DG16P02M036 \u201e\u00dadr\u017eba, opravy a\u00a0monitoring hr\u00e1z\u00ed historick\u00fdch rybn\u00edk\u016f jako na\u0161eho kulturn\u00edho d\u011bdictv\u00ed\u201c je mimo jin\u00e9 zam\u011b\u0159en na v\u00fdzkum hr\u00e1z\u00ed historick\u00fdch rybn\u00edk\u016f. Tvar t\u011bchto hr\u00e1z\u00ed je v\u00fdznamn\u00fd jak s\u00a0ohledem na stabilitu, tak s\u00a0ohledem na pr\u016fsaky t\u011bmito zemn\u00edmi t\u011blesy. V\u00fdzkum tvaru hr\u00e1z\u00ed je proto jedn\u00edm z\u00a0hlavn\u00edch \u00fakol\u016f \u0159e\u0161en\u00fdch v\u00a0r\u00e1mci uveden\u00e9ho projektu. Tvar je posuzov\u00e1n na z\u00e1klad\u011b r\u016fzn\u00fdch datov\u00fdch podklad\u016f v\u00a0celkem \u010dty\u0159ech oblastech [9]. V\u00a0pr\u016fb\u011bhu v\u00fdzkumn\u00fdch prac\u00ed bylo zji\u0161t\u011bno, \u017ee k\u00a0dan\u00e9mu \u00fa\u010delu jsou nejvhodn\u011bj\u0161\u00edm podkladem podrobn\u00e1 v\u00fd\u0161kopisn\u00e1 data vych\u00e1zej\u00edc\u00ed z\u00a0leteck\u00e9ho laserov\u00e9ho skenov\u00e1n\u00ed dopln\u011bn\u00e1 p\u0159\u00edpadn\u011b o\u00a0data zalo\u017een\u00e1 na vyhodnocen\u00ed leteck\u00fdch sn\u00edmk\u016f po\u0159\u00edzen\u00fdch prost\u0159ednictv\u00edm bezpilotn\u00edch prost\u0159edk\u016f (UAV\u00a0\u2013 Unmanned Aerial Vehicle) a\u00a0vyhodnocen\u00fdch fotogrammetrick\u00fdmi metodami. Tento \u010dl\u00e1nek se zam\u011b\u0159uje na prezentaci dvou aspekt\u016f takto veden\u00e9ho v\u00fdzkumu. P\u0159edn\u011b jsou prezentov\u00e1ny v\u00fdsledky posouzen\u00ed sklon\u016f svah\u016f rybni\u010dn\u00edch hr\u00e1z\u00ed v\u00a0oblasti Kostelecka a\u00a0Kou\u0159imska. Pro toto posouzen\u00ed byla vyu\u017eita v\u00fd\u0161kopisn\u00e1 data Digit\u00e1ln\u00edho modelu 5. generace po\u0159\u00edzen\u00e1 od \u010cesk\u00e9ho \u00fa\u0159adu zem\u011bm\u011b\u0159ick\u00e9ho a\u00a0katastr\u00e1ln\u00edho. Na z\u00e1klad\u011b t\u011bchto v\u00fdsledk\u016f pak byla zvolena hr\u00e1z Podbe\u010dv\u00e1rsk\u00e9ho rybn\u00edka, pro ni\u017e bylo provedeno posouzen\u00ed stability s\u00a0vyu\u017eit\u00edm modelu Slope Stability Analysis Program\u00a0\u2013 SSAP2010 [10].<\/p>\n

Tabulka 1. V\u00fdsledn\u00e9 hodnoty sklon\u016f pro hr\u00e1ze hodnocen\u00fdch rybn\u00edk\u016f (*uveden\u00e9 hodnoty pro rybn\u00edk Jan odpov\u00eddaj\u00ed stavu p\u0159ed rekonstrukc\u00ed (v sou\u010dasn\u00e9 dob\u011b ji\u017e tvar hr\u00e1ze odpov\u00edd\u00e1 aktu\u00e1ln\u00edm norm\u00e1m)
\n<\/em>Table 1. Resulting slope values for dams of assessed fishponds<\/h5>\n\"\"<\/a>\n

Hodnocen\u00ed tvaru hr\u00e1z\u00ed<\/h2>\n

Tvar hr\u00e1z\u00ed rybn\u00edk\u016f v\u00a0z\u00e1jmov\u00e9 oblasti byl posuzov\u00e1n s\u00a0vyu\u017eit\u00edm n\u00e1stroj\u016f a\u00a0metod GIS v\u00a0prost\u0159ed\u00ed ArcGIS. Z\u00e1jmov\u00e1 oblast je definov\u00e1na jako \u00fazem\u00ed zahrnuj\u00edc\u00ed povod\u00ed Jevansk\u00e9ho potoka, Nu\u010dick\u00e9ho potoka, Bylanky a\u00a0\u010d\u00e1st\u00ed povod\u00ed \u0160embery a\u00a0V\u00fdrovky. Celkov\u00e1 rozloha \u00fazem\u00ed \u010din\u00ed 533,3\u00a0km2<\/sup> a\u00a0nach\u00e1z\u00ed se v\u00a0n\u00ed celkem 31 rybn\u00edk\u016f s\u00a0rozlohou nad 1\u00a0ha. Poloha t\u011bchto rybn\u00edk\u016f je patrn\u00e1 z\u00a0mapy na obr. 1<\/em>. Hr\u00e1ze men\u0161\u00edch rybn\u00edk\u016f (s\u00a0rozlohou men\u0161\u00ed ne\u017e 1\u00a0ha) nebyly posuzov\u00e1ny p\u0159edev\u0161\u00edm z\u00a0toho d\u016fvodu, \u017ee u\u00a0men\u0161\u00edch rybn\u00edk\u016f by mohlo doj\u00edt ke zna\u010dn\u00e9mu zkreslen\u00ed v\u00fdsledk\u016f z\u00a0d\u016fvodu p\u0159\u00edli\u0161 mal\u00e9ho plo\u0161n\u00e9ho rozsahu jejich svah\u016f. Vedlej\u0161\u00edm d\u016fvodem pak byla skute\u010dnost, \u017ee u\u00a0men\u0161\u00edch rybn\u00edk\u016f jsou rizika vypl\u00fdvaj\u00edc\u00ed z\u00a0p\u0159\u00edpadn\u00e9 poruchy hr\u00e1ze obecn\u011b men\u0161\u00ed.<\/p>\n

Postup hodnocen\u00ed tvaru hr\u00e1ze<\/h2>\n

Podkladem pro hodnocen\u00ed sklon\u016f svah\u016f hr\u00e1z\u00ed rybn\u00edk\u016f byla podrobn\u00e1 v\u00fd\u0161kopisn\u00e1 data vych\u00e1zej\u00edc\u00ed z\u00a0leteck\u00e9ho laserov\u00e9ho skenov\u00e1n\u00ed povrchu. Konkr\u00e9tn\u011b byl pou\u017eit Digit\u00e1ln\u00ed model reli\u00e9fu 5. generace (DMR5G) po\u0159\u00edzen\u00fd od \u010cesk\u00e9ho \u00fa\u0159adu zem\u011bm\u011b\u0159ick\u00e9ho a\u00a0katastr\u00e1ln\u00edho (\u010c\u00daZK). Data jsou poskytov\u00e1na ve form\u011b mra\u010dna bod\u016f se sou\u0159adnicemi XYZ s\u00a0pr\u016fm\u011brnou hustotou cca 1 bod na \u010dtvere\u010dn\u00ed metr. V\u00fd\u0161kov\u00e1 p\u0159esnost dat se pohybuje kolem 0,18\u00a0m v\u00a0otev\u0159en\u00e9m ter\u00e9nu a\u00a00,3\u00a0m v\u00a0lesn\u00edch porostech [11]. P\u0159edchoz\u00ed v\u00fdzkumy prok\u00e1zaly, \u017ee takov\u00e1to p\u0159esnost je posta\u010duj\u00edc\u00ed k\u00a0popisu tvaru hr\u00e1z\u00ed [12]. Surov\u00e1 data poskytnut\u00e1 ve form\u011b ASCII souboru obsahuj\u00edc\u00edm XYZ sou\u0159adnice byla nejprve konvertov\u00e1na do form\u00e1tu ESRI SHAPEFILE a\u00a0n\u00e1sledn\u011b pou\u017eita k\u00a0vytvo\u0159en\u00ed rastrov\u00e9 v\u00fd\u0161kopisn\u00e9 vrstvy s\u00a0rozli\u0161en\u00edm 0,5\u00a0m. Z\u00a0t\u00e9to vrstvy byla n\u00e1sledn\u011b odvozena vrstva sklon\u016f vyj\u00e1d\u0159en\u00fdch v\u00a0procentech.<\/p>\n

Indikativn\u00ed hodnoty sklon\u016f n\u00e1vodn\u00edho a\u00a0vzdu\u0161n\u00edho l\u00edce jednotliv\u00fdch hr\u00e1z\u00ed byly stanovov\u00e1ny jako pr\u016fm\u011brn\u00e9 hodnoty v\u00a0r\u00e1mci ru\u010dn\u011b vykreslen\u00fdch plo\u0161ek s\u00a0vyu\u017eit\u00edm zon\u00e1ln\u00ed statistiky. Plo\u0161ky byly vykreslov\u00e1ny tak, aby spl\u0148ovaly n\u00e1sleduj\u00edc\u00ed po\u017eadavky:<\/p>\n