{"id":8282,"date":"2020-06-19T10:34:52","date_gmt":"2020-06-19T09:34:52","guid":{"rendered":"https:\/\/www.vtei.cz\/?p=8282"},"modified":"2024-07-17T10:34:43","modified_gmt":"2024-07-17T09:34:43","slug":"simulation-of-the-restoration-of-the-meander-jordan-of-the-orlice-river-and-its-impact-on-the-adjacent-quaternary-aquifer","status":"publish","type":"post","link":"https:\/\/www.vtei.cz\/en\/2020\/06\/simulation-of-the-restoration-of-the-meander-jordan-of-the-orlice-river-and-its-impact-on-the-adjacent-quaternary-aquifer\/","title":{"rendered":"Simulation of the restoration of the meander Jordan of the Orlice River and its impact on the adjacent quaternary aquifer"},"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

Velmi urgentn\u00ed v\u00fdzvou vodohospod\u00e1\u0159sk\u00fdch organizac\u00ed v\u00a0\u010cesk\u00e9 republice je problematika zadr\u017eov\u00e1n\u00ed vody v\u00a0krajin\u011b. Jedna z\u00a0iniciativ st\u00e1tn\u00edho podniku Povod\u00ed Labe je revitalizace meandru Jord\u00e1n na toku Orlice. N\u00e1vrat \u0159\u00ed\u010dn\u00edho toku do p\u016fvodn\u00edho koryta a\u00a0technick\u00fd z\u00e1sah, kter\u00fd zv\u00fd\u0161\u00ed hladinu do p\u016fvodn\u00ed \u00farovn\u011b, bude p\u0159edstavovat v\u00fdznamn\u00fd z\u00e1sah do vodn\u00edho re\u017eimu. Pozitivn\u00ed dopad se projev\u00ed v\u00a0p\u0159\u00edpad\u011b obou klimatick\u00fdch extr\u00e9m\u016f, povodn\u00ed i\u00a0sucha. Bezprost\u0159edn\u00edm dopadem bude zpomalen\u00ed odtoku povrchov\u00e9 vody, sou\u010dasn\u011b se v\u0161ak zv\u00fd\u0161en\u00ed hladiny Orlice projev\u00ed v\u00a0\u00favodn\u00ed f\u00e1zi revitalizace intenzivn\u011bj\u0161\u00ed b\u0159ehovou infiltrac\u00ed. V\u00fdzkumn\u00fd \u00fastav vodohospod\u00e1\u0159sk\u00fd T. G. Masaryka, v. v. i., z\u00a0pov\u011b\u0159en\u00ed Ministerstva \u017eivotn\u00edho prost\u0159ed\u00ed zah\u00e1jilo ji\u017e na konci roku 2018 monitoring re\u017eimu podzemn\u00edch vod v\u00a0p\u0159ilehl\u00e9m kvart\u00e9rn\u00edm kolektoru za aktu\u00e1ln\u00edho stavu p\u0159ed zah\u00e1jen\u00edm revitaliza\u010dn\u00edch opat\u0159en\u00ed. Hladina podzemn\u00edch vod byla\u00a0kontinu\u00e1ln\u011b m\u011b\u0159ena na \u010dty\u0159ech nov\u011b realizovan\u00fdch vrtech. P\u0159edkl\u00e1dan\u00e1 studie p\u0159edstavuje v\u00fdsledky matematick\u00e9ho modelu, kter\u00fd simuluje o\u010dek\u00e1van\u00fd dopad technick\u00e9ho z\u00e1sahu na zdroje podzemn\u00edch vod. P\u0159ipraven\u00e9 byly simulace sou\u010dasn\u00e9ho stavu a\u00a0stavu po revitalizaci s\u00a0nav\u00fd\u0161en\u00edm hladiny v\u00a0meandru o\u00a01\u00a0m a\u00a0o\u00a02\u00a0m. Podle v\u00fdsledk\u016f modelu bylo spo\u010d\u00edtan\u00e9 nav\u00fd\u0161en\u00ed z\u00e1soby podzemn\u00edch vod v\u00a0kvart\u00e9rn\u00edm kolektoru.<\/p>\n

\u00davod<\/h2>\n

P\u016fvodn\u00ed koryto \u0159eky Orlice bylo v\u00a0prostoru T\u00fdni\u0161t\u011b nad Orlic\u00ed v\u00a0minulosti nap\u0159\u00edmeno. Zrychlen\u00ed pr\u016ftoku zp\u016fsobilo zv\u00fd\u0161enou\u00a0hloubkovou erozi. Zahlouben\u00ed dna koryta se n\u00e1sledn\u011b projevilo i\u00a0na sn\u00ed\u017een\u00ed hladiny podzemn\u00ed vody v\u00a0p\u0159ilehl\u00e9m kvart\u00e9rn\u00edm kolektoru.<\/p>\n

Nevyhovuj\u00edc\u00ed sou\u010dasn\u00fd stav lze do jist\u00e9 m\u00edry napravit vhodn\u00fdmi \u00fapravami. Revitalizace koryt \u0159ek se pova\u017euje za vhodn\u00fd n\u00e1stroj ke\u00a0zlep\u0161en\u00ed n\u00edzk\u00fdch letn\u00edch pr\u016ftok\u016f. Lep\u0161\u00ed akumulace a\u00a0v\u00fdm\u011bny vody ve vodote\u010di a\u00a0v\u00a0p\u0159ilehl\u00e9m nivn\u00edm kolektoru podzemn\u00ed vody lze doc\u00edlit s\u00a0pomoc\u00ed z\u00e1sah\u016f do koryta. V\u00fdzkumn\u00edci a\u00a0vodohospod\u00e1\u0159i proto propaguj\u00ed revitalizaci \u0159ek jako jedno z\u00a0mitiga\u010dn\u00edch opat\u0159en\u00ed, kter\u00e9 zv\u00fd\u0161\u00ed odolnost vodn\u00edch zdroj\u016f na nep\u0159edv\u00eddateln\u00e9 zm\u011bny stavu vod v\u00a0d\u016fsledku zm\u011bny klimatu.<\/p>\n

Vyhodnocov\u00e1n\u00edm vliv\u016f revitalizac\u00ed \u0159ek se zab\u00fdvaj\u00ed v\u00fdzkumn\u00edci v\u00a0tuzemsku [1] i\u00a0v\u00a0zahrani\u010d\u00ed. Studie potvrzuj\u00ed, \u017ee revitalizace \u0159ek sn\u00ed\u017eila rychlosti odtoku, zv\u00fd\u0161ila akumula\u010dn\u00ed schopnost (storativitu) nivn\u00edho kolektoru a\u00a0nav\u00fd\u0161ila objem z\u00e1kladn\u00edho odtoku [2]. Intenzivn\u011bj\u0161\u00ed v\u00fdm\u011bna mezi podzemn\u00edmi a\u00a0povrchov\u00fdmi vodami skrz sedimenty \u0159\u00ed\u010dn\u00edho koryta je z\u00e1sadn\u00ed pro chemismus, biogeochemick\u00e9 procesy (okysli\u010denost vody, denitrifikace) a\u00a0ekologick\u00fd stav \u0159\u00ed\u010dn\u00edho prost\u0159ed\u00ed [3\u20136]. Z\u00e1sadn\u00edm parametrem charakterizuj\u00edc\u00edm komunikaci povrchov\u00fdch a\u00a0podzemn\u00edch vod je hydraulick\u00e1 v\u00fd\u0161ka \u0159eky [7]. Vliv za\u0159ez\u00e1v\u00e1n\u00ed koryta \u0159eky na hladiny podzemn\u00ed vody v\u00a0\u00fadoln\u00ed niv\u011b lze ov\u011b\u0159it pomoc\u00ed numerick\u00e9ho modelu [8].<\/p>\n

V\u00a0r\u00e1mci sou\u010dasn\u00e9ho vodohospod\u00e1\u0159sk\u00e9ho trendu, zadr\u017eov\u00e1n\u00ed vody v\u00a0krajin\u011b, z\u00edskal st\u00e1tn\u00ed podnik Povod\u00ed Labe finan\u010dn\u00ed prost\u0159edky na revitalizaci meandru Jord\u00e1n. Tato aktivita m\u016f\u017ee slou\u017eit jako modelov\u00e1 studie revitalizace cel\u00e9ho povod\u00ed Orlice a\u017e po Hradec Kr\u00e1lov\u00e9. Lokality podobn\u00fdch od\u0161krcen\u00fdch a\u00a0odstaven\u00fdch meandr\u016f Orlice zmapovala ve sv\u00e9 pr\u00e1ci nap\u0159\u00edklad Le\u017e\u00edkov\u00e1 [9]. V\u00a0r\u00e1mci prac\u00ed realizovan\u00fdch v\u00a0roce 2020 dojde k\u00a0navr\u00e1cen\u00ed toku \u0159eky Orlice do p\u016fvodn\u00edho koryta a\u00a0ke zv\u00fd\u0161en\u00ed hladiny v\u00a0\u0159ece sp\u00e1dov\u00fdm objektem pod meandrem. C\u00edlem studie V\u00daV TGM je modelov\u00e9 posouzen\u00ed dopad\u016f revitalizace meandru Jord\u00e1n na hydrogeologick\u00e9 pom\u011bry \u00fazem\u00ed a\u00a0na m\u00edstn\u00ed z\u00e1soby podzemn\u00ed vody.<\/p>\n

Metodika<\/h2>\n

Charakteristika modelov\u00e9ho \u00fazem\u00ed<\/h3>\n

Modelov\u00e9 \u00fazem\u00ed s\u00a0plochou 8,7\u00a0km2<\/sup> se nach\u00e1z\u00ed v\u00a0prostoru kvart\u00e9rn\u00edch fluvi\u00e1ln\u00edch sediment\u016f \u0159eky Orlice mezi obcemi Albrechtice nad Orlic\u00ed, T\u00fdni\u0161t\u011b nad Orlic\u00ed a\u00a0Petrovice (obr. 1<\/em>). V\u00a0jejich podlo\u017e\u00ed se vyskytuj\u00ed j\u00edlovce, prachovce a\u00a0sl\u00ednovce \u010desk\u00e9 k\u0159\u00eddov\u00e9 p\u00e1nve.<\/p>\n\"\"<\/a>\n

Obr. 1. Mapa modelov\u00e9ho \u00fazem\u00ed
\nFig. 1. Map of the model area<\/h6>\n

Na Orlici je dlouhodob\u011b sledov\u00e1n pr\u016ftok na profilu \u010cHM\u00da u\u00a0mostu silnice \u010d. 305 mezi T\u00fdni\u0161t\u011bm a\u00a0Albrechticemi. Podle eviden\u010dn\u00edho listu profilu \u010din\u00ed pr\u016fm\u011brn\u00fd ro\u010dn\u00ed pr\u016ftok 18,6\u00a0m3<\/sup>, co\u017e odpov\u00edd\u00e1 stavu vodom\u011bru 120\u00a0cm. Z\u00e1jmov\u00fdm \u00fazem\u00edm prot\u00e9k\u00e1 i\u00a0lev\u00fd p\u0159\u00edtok Orlice St\u0159\u00edbrn\u00fd potok. U\u00a0Albrechtic je \u0159eka p\u0159ehrazena jezem, kter\u00fd slou\u017e\u00ed k\u00a0vyu\u017eit\u00ed vodn\u00ed energie v\u00a0mal\u00e9 vodn\u00ed elektr\u00e1rn\u011b.<\/p>\n

Severov\u00fdchodn\u011b prot\u00e9k\u00e1 \u00fazem\u00edm vodn\u00ed n\u00e1hon Alba, kter\u00fd byl podle historick\u00fdch z\u00e1znam\u016f vybudov\u00e1n ve 14. stolet\u00ed a\u00a0slou\u017eil k\u00a0nap\u00e1jen\u00ed n\u011bkolika rybn\u00edk\u016f, ml\u00fdn\u016f a\u00a0pil [10]. Pr\u016fto\u010dn\u00e1 kapacita n\u00e1honu je 0,6\u00a0m3<\/sup>\/s\u00a0a\u00a0pr\u016fm\u011brn\u00fd pr\u016ftok, stabiln\u00ed v\u00a0cel\u00e9 d\u00e9lce je 0,35\u00a0m3<\/sup>\/s\u00a0[11]. Vodu dopl\u0148uj\u00ed p\u0159\u00edtoky z\u00a0prav\u00e9 strany (p\u0159edev\u0161\u00edm Ole\u0161nick\u00fd potok), a\u00a0naopak k\u00a0odtok\u016fm doch\u00e1z\u00ed na lev\u00e9 stran\u011b. Povrchov\u00e1 voda v\u00a0kan\u00e1lu pravd\u011bpodobn\u011b komunikuje i\u00a0s\u00a0kvart\u00e9rn\u00ed zvodn\u00ed. Souvislost hladiny v\u00a0kan\u00e1le s\u00a0hladinou podzemn\u00ed vody potvrzuje z\u00e1znam z\u00a0archivn\u00edho vrtu T-1, realizovan\u00e9ho v\u00a0roce 2001 v\u00a0t\u011bsn\u00e9 bl\u00edzkosti kan\u00e1lu. Hladina podzemn\u00ed vody (HPV) zde dosahovala hloubky 0,75\u00a0m pod ter\u00e9nem.<\/p>\n

V\u00a0\u0161ir\u0161\u00ed oblasti je odtok regulov\u00e1n s\u00edt\u00ed m\u011blk\u00fdch dren\u00e1\u017en\u00edch p\u0159\u00edkop\u016f. \u010cast\u00e9 jsou v\u00fdskyty zamok\u0159en\u00fdch ploch a\u00a0stojat\u00e9 vody v\u00a0od\u0161krcen\u00fdch meandrech. V\u00a0oblasti je n\u011bkolik mal\u00fdch rybn\u00edk\u016f (Na Horce u\u00a0\u0160t\u011bp\u00e1novska, Na L\u00e1nech mezi silnic\u00ed \u010d. 11 a\u00a0\u017eelezni\u010dn\u00ed trat\u00ed).<\/p>\n

Pr\u016fm\u011brn\u00e1 ro\u010dn\u00ed teplota \u010din\u00ed 8\u20139 \u00b0C a\u00a0pr\u016fm\u011brn\u00fd ro\u010dn\u00ed sr\u00e1\u017ekov\u00fd \u00fahrn 600\u2013650\u00a0mm. Po\u010det dn\u016f se sn\u011bhovou pokr\u00fdvkou kol\u00eds\u00e1 mezi 50\u201360 dny a\u00a0jej\u00ed maxim\u00e1ln\u00ed v\u00fd\u0161ka \u010din\u00ed 15\u201320 cm [12].<\/p>\n

Geometrie modelu<\/h3>\n

Modelov\u00e9 t\u011bleso je prostorov\u011b definov\u00e1no z\u00a0povrchu digit\u00e1ln\u00edm modelem ter\u00e9nu (DEM 4G) v\u00a0rozli\u0161en\u00ed 10 \u00d7 10 m. P\u0159esnost DEM 4G je na odkryt\u00e9 plo\u0161e 30 cm na zalesn\u011bn\u00e9 100 cm. B\u00e1zi modelov\u00e9ho t\u011blesa tvo\u0159\u00ed kontakt kvart\u00e9rn\u00edch sediment\u016f s\u00a0podlo\u017e\u00edm. Pro jeho vymezen\u00ed jsme pou\u017eili soubor 134 archivn\u00edch vrt\u016f z\u00a0Geofondu \u010cR. Ze souboru archivn\u00edch vrt\u016f byla interpola\u010dn\u00ed metodou Kriging vygenerov\u00e1na plocha podlo\u017e\u00ed kvart\u00e9rn\u00edho kolektoru. Do souboru byly p\u0159idan\u00e9 i\u00a0body na okraji prohlubn\u011b s\u00a0nulovou hloubkou kolektoru, kter\u00e9 charakterizuj\u00ed v\u00fdchozy podlo\u017en\u00edch k\u0159\u00eddov\u00fdch hornin. K\u0159\u00eddov\u00e9 horniny v\u00a0podlo\u017e\u00ed kvart\u00e9rn\u00edch sediment\u016f p\u0159edstavuj\u00ed prachovce, sl\u00ednovce a\u00a0j\u00edlovce s\u00a0ni\u017e\u0161\u00ed propustnost\u00ed, proto jsou pro \u00fa\u010dely modelu definovan\u00e9 jako nepropustn\u00e9 podlo\u017e\u00ed. Mocnosti modelov\u00e9ho t\u011blesa jsou zn\u00e1zorn\u011bny na obr. 2<\/em>.<\/p>\n\"\"<\/a>\n

Obr. 2. Situace modelov\u00e9ho \u00fazem\u00ed se zn\u00e1zorn\u011bn\u00edm mocnost\u00ed kvart\u00e9rn\u00edho kolektoru
\nFig. 2. Situation of model area with representation of quaternary aquifer thickness<\/h6>\n

Gridov\u00e1 s\u00ed\u0165<\/h3>\n

V\u00fdpo\u010detn\u00ed s\u00ed\u0165 (obr. 3<\/em>) je definov\u00e1na s\u00a0rozli\u0161en\u00edm 25 \u00d7 25 m. V\u00a0prostoru revitalizace meandru Jord\u00e1n je s\u00ed\u0165 zahu\u0161t\u011bna na rozli\u0161en\u00ed 6,25 \u00d7 6,25\u00a0m. Bu\u0148ky mimo modelovou oblast jsou neaktivn\u00ed.<\/p>\n

Vymezen\u00ed modelov\u00e9 oblasti a\u00a0okrajov\u00e9 podm\u00ednky<\/h3>\n

Modelov\u00e1 oblast je vymezena tak, aby hranice oblasti co nejl\u00e9pe odpov\u00eddaly re\u00e1ln\u00fdm podm\u00ednk\u00e1m, kter\u00e9 ur\u010duj\u00ed hydrogeologick\u00fd re\u017eim v\u00a0oblasti (obr. 3<\/em>). JZ okraj reprezentuje geologick\u00e1 hranice \u2013 v\u00fdchozy podlo\u017en\u00edch k\u0159\u00eddov\u00fdch hornin. Zde je v\u00a0modelu definovan\u00e1 hranice nulov\u00e9ho pr\u016ftoku (No Flow). SV hranici reprezentuje n\u00e1hon Alba, kde je v\u00a0modelu definovan\u00e1 okrajov\u00e1 podm\u00ednka typu \u0159eka (River). Zde v\u00a0z\u00e1vislosti na hydraulick\u00e9 v\u00fd\u0161ce hladiny ve vodote\u010di doch\u00e1z\u00ed bu\u010f k\u00a0dotaci, nebo odvodn\u011bn\u00ed podzemn\u00ed vody. V\u00fd\u0161ky hladiny byly odhadnut\u00e9 na z\u00e1klad\u011b digit\u00e1ln\u00edho modelu ter\u00e9nu mezi 253,5\u00a0m n. m. na V\u00a0a\u00a0250,5\u00a0m n. m. na S.<\/p>\n\"\"<\/a>\n

Obr. 3. Gridov\u00e1 s\u00ed\u0165 modelu a\u00a0okrajov\u00e9 podm\u00ednky (Constant Head \u2013 konstantn\u00ed hladina, River \u2013 \u0159eka, Drain \u2013 dren\u00e1\u017e, No Flow \u2013 bez pr\u016ftoku)
\nFig. 3. Model grid and boundary conditions<\/h6>\n

SZ hranice je rozd\u011blena na dv\u011b \u010d\u00e1sti. Prvn\u00ed \u010d\u00e1st reprezentuje Orlice, v\u00a0modelu definovan\u00e1 jako okrajov\u00e1 podm\u00ednka typu \u0159eka (River). Druh\u00e1 \u010d\u00e1st je spojnice mezi \u0159ekou Orlic\u00ed a\u00a0n\u00e1honem Alba. Linie spojnice je zhruba kolm\u00e1 na p\u0159edpokl\u00e1dan\u00fd sm\u011br proud\u011bn\u00ed podzemn\u00ed vody. V\u00a0modelu je zde definovan\u00e1 okrajov\u00e1 podm\u00ednka typu ust\u00e1len\u00e1 hladina (Constant Head).<\/p>\n

JV okraj prob\u00edh\u00e1 \u010d\u00e1ste\u010dn\u011b po vodote\u010d\u00edch Orlice a\u00a0prav\u00e9m bezejmenn\u00e9m p\u0159\u00edtoku, kter\u00fd spojuje Albu a\u00a0Orlici. Tato \u010d\u00e1st je v\u00a0modelu definovan\u00e1 okrajovou podm\u00ednkou typu \u0159eka. Asi 450 m dlouh\u00fd \u00fasek okraje je spojnic\u00ed mezi \u0159ekou Orlic\u00ed a\u00a0geologickou hranic\u00ed s\u00a0v\u00fdchozy hornin podlo\u017e\u00ed. Tato linie je v\u00a0modelu definov\u00e1na jako okrajov\u00e1 podm\u00ednka typu ust\u00e1len\u00e1 hladina ve v\u00fd\u0161ce odpov\u00eddaj\u00edc\u00ed hladin\u011b v\u00a0Orlici.<\/p>\n

Orlice, z\u00e1sadn\u011b ur\u010duj\u00edc\u00ed hydraulick\u00e9 pom\u011bry podzemn\u00ed vody, v modelov\u00e9 oblasti p\u0159edstavuje \u0159\u00edd\u00edc\u00ed podm\u00ednku i v centr\u00e1ln\u00ed \u010d\u00e1sti \u00fazem\u00ed. Nejd\u016fle\u017eit\u011bj\u0161\u00edm vstupem do modelu jsou zde hydraulick\u00e9 v\u00fd\u0161ky hladiny Orlice op\u00edraj\u00edc\u00ed se o n\u011bkolik geodeticky zam\u011b\u0159en\u00fdch \u00farovn\u00ed hladiny. Prvn\u00ed op\u011brn\u00fd bod je dlouhodob\u011b sledovan\u00fd profil \u010cHM\u00da T\u00fdni\u0161t\u011b. Nula vodo\u010dtu je zde geodeticky zam\u011b\u0159ena ve v\u00fd\u0161ce 244,50\u00a0m n. m. a\u00a0pr\u016fm\u011brn\u00fd ro\u010dn\u00ed stav hladiny je 120\u00a0cm (pr\u016ftok 18,6 m3<\/sup>\/s). Dne 22. 3. 2013 byla geodeticky zam\u011b\u0159ena hladina Orlice v\u00a0m\u00edst\u011b navrhovan\u00e9ho sp\u00e1dov\u00e9ho objektu revitalizovan\u00e9ho meandru Jord\u00e1n. V\u00fd\u0161ka byla 243,36\u00a0m n. m. a\u00a0tomu odpov\u00eddal pr\u016ftok na profilu T\u00fdni\u0161t\u011b 16,6 m3<\/sup>\/s. Na z\u00e1klad\u011b p\u0159\u00ed\u010dn\u00e9ho profilu \u0159eky v\u00a0m\u00edst\u011b m\u011b\u0159en\u00ed odhadujeme referen\u010dn\u00ed v\u00fd\u0161ku hladiny pro pr\u016fm\u011brn\u00fd ro\u010dn\u00ed pr\u016ftok 18,6\u00a0m3<\/sup>\/s\u00a0na 243,40\u00a0m n. m. \u00dadaje k\u00a0v\u00fdpo\u010dtu v\u00fd\u0161ky v\u00a0m\u00edst\u011b sp\u00e1dov\u00e9ho objektu Jord\u00e1n poskytla spole\u010dnost \u0160indlar, s. r. o.<\/p>\n

Podle topografick\u00fdch podklad\u016f (Z\u00e1kladn\u00ed mapa \u010cR 1 : 10 000 a\u00a01 : 50 000) byla zmapovan\u00e1 dren\u00e1\u017en\u00ed s\u00ed\u0165, pro kterou byla definovan\u00e1 okrajov\u00e1 podm\u00ednka typu dren\u00e1\u017e (Drain). Tento typ okrajov\u00e9 podm\u00ednky na rozd\u00edl od typu \u0159eka umo\u017e\u0148uje pouze odvodn\u011bn\u00ed podzemn\u00ed vody. \u00darove\u0148 odvodn\u011bn\u00ed je definov\u00e1na ve v\u00fd\u0161ce 1\u00a0m pod \u00farovn\u00ed okoln\u00edho ter\u00e9nu.<\/p>\n

Pro celou plochu modelu je definov\u00e1na okrajov\u00e1 podm\u00ednka dotace podzemn\u00ed vody ze sr\u00e1\u017eek (Recharge). Hodnota dotace byla spo\u010d\u00edtan\u00e1 z\u00a0pr\u016fm\u011brn\u00e9ho sr\u00e1\u017ekov\u00e9ho \u00fahrnu 600\u2013650\u00a0mm [12] a\u00a0to jako t\u0159etinov\u00fd pod\u00edl celkov\u00e9ho sr\u00e1\u017ekov\u00e9ho \u00fahrnu, tj. 208\u00a0mm, resp. 5,7 \u00d7 10-4<\/sup> m\/den.<\/p>\n

Hydraulick\u00e1 vodivost<\/h3>\n

Z\u00a0archivn\u00edch vrt\u016f v\u00a0datab\u00e1zi Geofond byly z\u00edskan\u00e9 \u00fadaje o\u00a0hydraulick\u00e9 vodivosti\u00a0(k). V\u00a0oblasti je k\u00a0dispozici sedm vrt\u016f s\u00a0\u00fadaji uveden\u00fdmi v\u00a0tabulce 1<\/em>.<\/p>\n

Tabulka 1. Charakteristika pou\u017eit\u00fdch vrt\u016f
\nTable 1. Characteristics of the archive boreholes<\/h5>\n\"\"<\/a>\n

P\u0159i vylou\u010den\u00ed extr\u00e9mn\u00edch (max. a\u00a0min.) hodnot byla jako pr\u016fm\u011brn\u00e1 hodnota hydraulick\u00e9 vodivosti pou\u017eita 1,8 \u00d7 10-4<\/sup> m\/s. Hodnoty Kxy a\u00a0Kz jsou nad\u00e1le zp\u0159esn\u011bn\u00e9 v\u00a0r\u00e1mci kalibrace hydraulick\u00e9ho modelu.<\/p>\n

Kalibrace<\/h3>\n

Ke kalibraci poslou\u017eili \u00fadaje o\u00a0hladin\u011b podzemn\u00ed vody z\u00a0v\u00fdb\u011bru 14 vrt\u016f z\u00a0archivu Geofondu a\u00a04 nov\u00fdch pr\u016fzkumn\u00fdch vrt\u016f v\u00a0prostoru meandru Jord\u00e1n (tabulka\u00a02<\/em>). U\u00a0pou\u017eit\u00fdch vrt\u016f byla \u00farove\u0148 hladiny stanoven\u00e1 z\u00a0hloubky hladiny a\u00a0geodeticky zam\u011b\u0159en\u00e9 nadmo\u0159sk\u00e9 v\u00fd\u0161ky odm\u011brn\u00e9ho bodu, p\u0159\u00edpadn\u011b hodnoty DEM.<\/p>\n

Tabulka 2. Pou\u017eit\u00e9 hladiny podzemn\u00ed vody pro kalibraci modelu
\nTable 2. Groundwater levels used for model calibration<\/h5>\n\"\"<\/a>\n

Ze \u010dty\u0159\u00a0nov\u00fdch vrt\u016f realizovan\u00fdch V\u00daV TGM za \u00fa\u010delem z\u00edsk\u00e1n\u00ed informac\u00ed o\u00a0re\u017eimu podzemn\u00ed vody v\u00a0kvart\u00e9rn\u00edm kolektoru p\u0159ed revitalizac\u00ed meandru Jord\u00e1n, je k\u00a0dispozici \u010dasov\u00e1 \u0159ada hladin podzemn\u00ed vody. Na obr. 4<\/em> jsou pr\u016fb\u011bhy hladin srovnan\u00e9 s\u00a0vodn\u00edm stavem na profilu \u010cHM\u00da T\u00fdni\u0161t\u011b nad Orlic\u00ed.<\/p>\n\"\"<\/a>\n

Obr. 4. Pr\u016fb\u011bhy hladin podzemn\u00ed vody na monitorovac\u00edch vrtech V\u00daV TGM a\u00a0v\u00a0\u0159ece Orlici
\nFig. 4. Groundwater level on VUV TGM monitoring wells and in Orlice River<\/h6>\n

Vrty HV1 a\u00a0HV2 jsou um\u00edst\u011bn\u00e9 v\u00a0bezprost\u0159edn\u00ed bl\u00edzkosti koryta Orlice ve vzd\u00e1lenosti n\u011bkolik des\u00edtek metr\u016f uvnit\u0159\u00a0meandru. Z\u00a0grafu je proto jasn\u011b z\u0159eteln\u00e9, \u017ee hladiny podzemn\u00ed vody v\u00a0t\u011bchto objektech velmi rychle reaguj\u00ed na zm\u011bny vodn\u00edch stav\u016f v\u00a0\u0159ece. Vrty HV3 a\u00a0HV4 jsou um\u00edst\u011bn\u00e9 ve v\u011bt\u0161\u00ed vzd\u00e1lenosti od koryta \u0159eky (100\u00a0m, resp. 200\u00a0m). I\u00a0na nich se sice projevuje souvislost s\u00a0vodn\u00edm stavem v\u00a0\u0159ece, nicm\u00e9n\u011b kol\u00eds\u00e1n\u00ed hladiny podzemn\u00ed vody ji\u017e nen\u00ed tak v\u00fdrazn\u00e9.<\/p>\n

Prvn\u00ed modelov\u00e9 simulace nazna\u010dily, \u017ee hydraulick\u00e1 vodivost v\u00a0modelov\u00e9m \u00fazem\u00ed nen\u00ed homogenn\u00ed a\u00a0pro spr\u00e1vn\u00e9 fungov\u00e1n\u00ed modelu byl nutn\u00fd subjektivn\u00ed z\u00e1sah. P\u0159i zad\u00e1n\u00ed jedin\u00e9 zpr\u016fm\u011brovan\u00e9 hodnoty hydraulick\u00e9 vodivosti toti\u017e doch\u00e1zelo lok\u00e1ln\u011b k\u00a0velk\u00fdm odchylk\u00e1m mezi m\u011b\u0159en\u00fdmi a\u00a0modelov\u00fdmi hladinami podzemn\u00ed vody. Proto jsme nejprve hodnoty hydraulick\u00e9 vodivosti sn\u00ed\u017eili v\u00a0oblasti nejni\u017e\u0161\u00ed \u0159\u00ed\u010dn\u00ed terasy, vymezen\u00e9 na z\u00e1klad\u011b topografick\u00e9 mapy a\u00a0digit\u00e1ln\u00edho modelu ter\u00e9nu. V\u00a0dal\u0161\u00edm kroku byla hydraulick\u00e1 vodivost sn\u00ed\u017een\u00e1 i\u00a0v\u00a0men\u0161\u00ed plo\u0161e pod meandrem Jord\u00e1n. Tato varianta (obr. 5<\/em>) se uk\u00e1zala jako nejl\u00e9pe odr\u00e1\u017eej\u00edc\u00ed re\u00e1ln\u00e9 m\u011b\u0159en\u00e9 hodnoty hladin podzemn\u00ed vody.<\/p>\n\"\"<\/a>\n

Obr. 5. Simulovan\u00e9 hladiny podzemn\u00ed vody p\u0159i zaveden\u00ed plo\u0161n\u00e9 heterogenity hydraulick\u00e9 vodivosti (Measured GWL \u2013 zm\u011b\u0159en\u00e1 HPV, River \u2013 \u0159eka, Drain \u2013 dren\u00e1\u017e, No Flow \u2013 bez pr\u016ftoku, Hydraulic Conductivity \u2013 hydraulick\u00e1 vodivost, Value \u2013 hodnota, Groundwater level \u2013 hladina podzemn\u00ed vody)
\nFig. 5. Resulting groundwater levels for simulation with laterally heterogenic hydraulic conductivity
\nPozn.: Modr\u00e9 popisky pozorovac\u00edch vrt\u016f znamenaj\u00ed pozitivn\u00ed odchylky zm\u011b\u0159en\u00fdch hladin v\u00a0m, \u010derven\u00e9 negativn\u00ed, hydraulick\u00e9 vodivosti jsou vyj\u00e1d\u0159en\u00e9 v\u00a0jednotk\u00e1ch m\/den, modr\u00e9 plochy jsou oblasti zaplaven\u00fdch bun\u011bk.<\/h6>\n

Ni\u017e\u0161\u00ed propustnost sediment\u016f nejni\u017e\u0161\u00ed terasy m\u016f\u017ee b\u00fdt zp\u016fsobena odli\u0161n\u00fdmi podm\u00ednkami sedimentace p\u0159i tvorb\u011b jednotliv\u00fdch terasov\u00fdch stup\u0148\u016f. Oblast ni\u017e\u0161\u00ed propustnosti pod meandrem Jord\u00e1n lze vysv\u011btlit lok\u00e1ln\u00ed zm\u011bnou facie sedimentace na jemn\u011bj\u0161\u00ed frakci. Na popisovanou variabilitu prost\u0159ed\u00ed \u00fadoln\u00edch niv upozor\u0148uje i\u00a0Kr\u00e1sn\u00fd a\u00a0kol. [13]. Mo\u017en\u00fd je ale tak\u00e9 vliv p\u0159\u00edsunu materi\u00e1lu p\u0159\u00edtokem ze severov\u00fdchodu ze sm\u011bru od sou\u010dasn\u00e9ho rybn\u00edku Na L\u00e1nech u\u00a0are\u00e1lu Elitex.<\/p>\n

V\u00fdsledky a\u00a0diskuse<\/h2>\n

Stacion\u00e1rn\u00ed model proud\u011bn\u00ed podzemn\u00ed vody je zkonstruov\u00e1n na z\u00e1klad\u011b dlouhodob\u00fdch pr\u016fm\u011brn\u00fdch veli\u010din okrajov\u00fdch podm\u00ednek. V\u00fdsledky modelu je proto pot\u0159eba ch\u00e1pat jako teoretick\u00fd stav, dosa\u017een\u00fd po dlouhodob\u011b konstantn\u00edch podm\u00ednk\u00e1ch. Jde o\u00a0zjednodu\u0161enou simulaci p\u0159\u00edrodn\u00edch proces\u016f, kter\u00e1 nepostihuje vlivy \u010dasov\u00e9 prom\u011bnlivosti vstupn\u00edch parametr\u016f.<\/p>\n

Podle v\u00fdsledk\u016f modelu se na n\u011bkter\u00fdch ploch\u00e1ch bl\u00ed\u017e\u00ed hladina podzemn\u00ed vody \u00farovni ter\u00e9nu. Tyto prostory se st\u00e1vaj\u00ed oblastmi nejistot, proto\u017ee nar\u00e1\u017e\u00edme na omezen\u00ed dan\u00e9 nep\u0159esnost\u00ed DEM. Zde bychom pro adekv\u00e1tn\u00ed \u0159e\u0161en\u00ed pot\u0159ebovali pracovat s\u00a0p\u0159esn\u011bji\u00a0zam\u011b\u0159en\u00fdmi ter\u00e9nn\u00edmi daty. Dal\u0161\u00ed nejistotu p\u0159edstavuj\u00ed nezmapovan\u00e9 dren\u00e1\u017en\u00ed p\u0159\u00edkopy. Zaplaven\u00e9 plochy, ozna\u010den\u00e9 na obr. 5<\/em>, se nach\u00e1z\u00ed v\u00a0m\u00edstech, kde skute\u010dn\u011b doch\u00e1z\u00ed k\u00a0v\u00fdskytu hladiny podzemn\u00ed vody v\u00a0\u00farovni ter\u00e9nu ve form\u011b men\u0161\u00edch rybn\u00edk\u016f, zaslepen\u00fdch meandr\u016f nebo pouze zamok\u0159en\u00fdch ploch:<\/p>\n