{"id":1586,"date":"2016-02-09T07:21:02","date_gmt":"2016-02-09T07:21:02","guid":{"rendered":"http:\/\/www.vtei.cz\/?p=1586"},"modified":"2024-07-16T10:36:41","modified_gmt":"2024-07-16T09:36:41","slug":"influence-of-barometric-pressure-on-the-water-level-at-the-observation-wells","status":"publish","type":"post","link":"https:\/\/www.vtei.cz\/en\/2016\/02\/influence-of-barometric-pressure-on-the-water-level-at-the-observation-wells\/","title":{"rendered":"Influence of barometric pressure on the water level at the observation wells"},"content":{"rendered":"

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

Souhrn<\/h2>\n

P\u0159\u00edsp\u011bvek se zab\u00fdv\u00e1 vlivem zm\u011bn barometrick\u00e9ho tlaku na\u00a0\u00farove\u0148 hladiny vody ve\u00a0vrtech a\u00a0dal\u0161\u00edch\u00a0pozorovac\u00edch sond\u00e1ch podzemn\u00edch vod. Obsahuje rozbor souvisej\u00edc\u00edch probl\u00e9m\u016f p\u0159i m\u011b\u0159en\u00ed \u00farovn\u011b hladiny podzemn\u00ed vody. Je uveden jednoduch\u00fd postup zji\u0161t\u011bn\u00ed citlivosti hladiny v\u00a0sond\u00e1ch na\u00a0zm\u011bny tlaku vzduchu pomoc\u00ed ukazatele BE (barometric efficiency). Je uk\u00e1z\u00e1na interpretace velikosti a\u00a0vlastnost\u00ed t\u00e9to citlivosti k\u00a0syst\u00e9mu sonda-kolektor a\u00a0p\u0159edlo\u017eeno n\u011bkolik konkr\u00e9tn\u00edch p\u0159\u00edklad\u016f pozorovac\u00edch sond s\u00a0charakteristick\u00fdmi vlastnostmi.<\/p>\n

\u00davod<\/h2>\n

Ve\u00a0V\u00fdzkumn\u00e9m \u00fastavu vodohospod\u00e1\u0159sk\u00e9m T. G. Masaryka,\u00a0v.\u2009v.\u2009i., jsou od\u00a0roku 2010 k\u00a0m\u011b\u0159en\u00ed v\u00fd\u0161ky hladiny povrchov\u00e9 a\u00a0podzemn\u00ed vody pou\u017e\u00edv\u00e1ny sn\u00edma\u010de absolutn\u00edho tlaku s\u00a0kompenzac\u00ed k\u00a0barometrick\u00e9mu tlaku. Pro r\u016fzn\u00e9 \u00fakoly byla takto sledov\u00e1na hladina podzemn\u00ed vody na\u00a0v\u00edce ne\u017e t\u0159iceti objektech, p\u0159edev\u0161\u00edm hydrogeologick\u00fdch vrtech, studn\u00edch a\u00a0d\u016fln\u00edch d\u00edlech. Ze z\u00edskan\u00fdch dat o\u00a0hladin\u00e1ch podzemn\u00ed vody a\u00a0tlaku vzduchu bylo mo\u017eno prakticky ov\u011b\u0159it vliv barometrick\u00e9ho tlaku na\u00a0\u00farove\u0148 hladiny ve\u00a0sledovan\u00fdch objektech.<\/p>\n\"kasparek-2\"<\/a>\n

Zp\u016fsoby m\u011b\u0159en\u00ed \u00farovn\u011b hladiny podzemn\u00ed vody<\/h2>\n

P\u0159\u00edm\u00e9 zji\u0161t\u011bn\u00ed \u00farovn\u011b hladiny podzemn\u00ed vody je mo\u017en\u00e9 r\u016fzn\u00fdmi hloubkov\u00fdmi sondami do\u00a0povrchu zemsk\u00e9ho dosahuj\u00edc\u00edmi k\u00a0t\u00e9to hladin\u011b. Tyto sondy mohou b\u00fdt zhotoven\u00e9 a\u00a0ur\u010den\u00e9 k\u00a0sledov\u00e1n\u00ed hladiny podzemn\u00ed vody, tj.\u00a0pozorovac\u00ed vrty nebo podobn\u00e1 za\u0159\u00edzen\u00ed jako vrty hydrogeologick\u00e9, vod\u00e1rensk\u00e9 vrty a\u00a0studny nebo\u00a0objekty jin\u00e9ho p\u016fvodn\u00edho ur\u010den\u00ed, v\u00fdkopy, t\u011b\u017eebn\u00ed a\u00a0d\u016fln\u00ed d\u00edla, pop\u0159.\u00a0vhodn\u00e9 p\u0159\u00edrodn\u00ed \u00fatvary.<\/p>\n

Technick\u00fdm proveden\u00edm se sondy d\u011bl\u00ed na\u00a0otev\u0159en\u00e9, kde je zji\u0161\u0165ov\u00e1na v\u00fd\u0161ka hladiny podzemn\u00ed vody v\u00a0sond\u011b, a\u00a0uzav\u0159en\u00e9, kde je do\u00a0horninov\u00e9ho prost\u0159ed\u00ed um\u00edst\u011bn od\u00a0atmosf\u00e9ry izolovan\u00fd tlakom\u011br m\u011b\u0159\u00edc\u00ed tlak v\u00a0kolektoru (uzav\u0159en\u00fd piezometr). K\u00a0uzav\u0159en\u00fdm sond\u00e1m pat\u0159\u00ed tak\u00e9 vrty s\u00a0tlakov\u00fdm zhlav\u00edm, ve\u00a0kter\u00fdch m\u011b\u0159\u00edme tlak vody art\u00e9sk\u00fdch zvodn\u00ed. D\u00e1le popisovan\u00e1 problematika vlivu barometrick\u00e9ho tlaku na\u00a0v\u00fd\u0161ku hladiny se vztahuje k\u00a0otev\u0159en\u00fdm sond\u00e1m.<\/p>\n

Hladinu m\u011b\u0159\u00edme hladinom\u011bry, kter\u00e9 mohou b\u00fdt kontaktn\u00ed, nebo tlakov\u00e9. Kontaktn\u00ed hladinom\u011bry pro kontinu\u00e1ln\u00ed z\u00e1znam jsou plov\u00e1kov\u00e9 nebo ultrazvukov\u00e9, pro bodov\u00e9 m\u011b\u0159en\u00ed se b\u011b\u017en\u011b pou\u017e\u00edv\u00e1 p\u00e1smo se signalizac\u00ed dosa\u017een\u00ed hladiny elektrick\u00fdm kontaktem nebo akustickou p\u00ed\u0161\u0165alou. M\u011b\u0159\u00ed se svisl\u00e1 vzd\u00e1lenost od\u00a0definovan\u00e9ho odm\u011brn\u00e9ho bodu k\u00a0hladin\u011b.<\/p>\n

Tlakov\u00e9 hladinom\u011bry jsou tlakom\u011bry absolutn\u00edho tlaku nebo tlakom\u011bry relativn\u00edho tlaku s\u00a0kompenza\u010dn\u00ed kapil\u00e1rou. Absolutn\u00ed tlak je celkov\u00fd tlak v\u00a0kapalin\u011b (tj.\u00a0hydrostatick\u00fd a\u00a0barometrick\u00fd) a\u00a0p\u0159i m\u011b\u0159en\u00ed voln\u00e9 hladiny je t\u0159eba barometrick\u00fd tlak od\u00a0celkov\u00e9ho tlaku v\u00a0kapalin\u011b ode\u010d\u00edtat. Hladinom\u011bry s\u00a0kompenza\u010dn\u00ed kapil\u00e1rou porovn\u00e1vaj\u00ed tlak kapaliny s\u00a0barometrick\u00fdm tlakem (v\u00a0kabelu mezi z\u00e1znamovou jednotkou a\u00a0sn\u00edma\u010dem pod hladinou je kapil\u00e1ra pro vzduch). Tlakov\u00e9 hladinom\u011bry m\u011b\u0159\u00ed tlak, resp. v\u00fd\u0161ku vodn\u00edho sloupce nad sn\u00edma\u010dem.<\/p>\n

Nejvhodn\u011bj\u0161\u00ed sondou pro sledov\u00e1n\u00ed hladiny podzemn\u00ed vody je pozorovac\u00ed vrt, kter\u00fd je principem a\u00a0proveden\u00edm shodn\u00fd s\u00a0otev\u0159en\u00fdm piezometrem. Ten je na\u00a0z\u00e1klad\u011b hydrogeologick\u00fdch dat p\u0159edpokl\u00e1dan\u00fdch a\u00a0ov\u011b\u0159en\u00fdch p\u0159i vrt\u00e1n\u00ed technicky proveden ke\u00a0sledov\u00e1n\u00ed jedn\u00e9 konkr\u00e9tn\u00ed zvodn\u011b, se kterou je dob\u0159e hydraulicky propojen. Od\u00a0ostatn\u00edch kolektor\u016f m\u00e1 b\u00fdt izolov\u00e1n. Perforace pa\u017een\u00ed vrtu je pod \u00farovn\u00ed hladiny a\u00a0prostor vrtu nad hladinou je ventilov\u00e1n do\u00a0atmosf\u00e9ry.<\/p>\n\"kasparek-1\"<\/a>\n

Obr.\u00a01. Vrt V-28 Bu\u010dnice (polick\u00e1 k\u0159\u00eddov\u00e1 p\u00e1nev), zm\u011bna hladiny v\u00a0z\u00e1vislosti na\u00a0zm\u011bn\u011b barometrick\u00e9ho tlaku pro interval 1 hod, BE = -0,7
\nFig. 1. Well V-28 Bucnice (Police Basin), level change depending on the change in barometric pressure for interval of 1 h, BE = -0,7<\/h6>\n

Ovlivn\u011bn\u00ed v\u00fd\u0161ky hladiny v\u00a0sond\u011b barometrick\u00fdm tlakem<\/h2>\n

\u00darove\u0148 hladiny v\u00a0sond\u011b je d\u00e1na vyv\u00e1\u017een\u00fdm stavem protich\u016fdn\u00e9ho tlaku vody a\u00a0vzduchu v\u00a0sond\u011b. Tlak vody ve\u00a0zvodni krom\u011b re\u017eimu podzemn\u00ed vody mohou ovliv\u0148ovat dal\u0161\u00ed jevy, zn\u00e1m\u00e9 jsou slapov\u00e9 a\u00a0seismick\u00e9 vlivy, barometrick\u00fd tlak ur\u010duje po\u010das\u00ed. V\u00a0ide\u00e1ln\u00edm pozorovac\u00edm vrtu je tlak vzduchu nad hladinou shodn\u00fd s\u00a0barometrick\u00fdm tlakem a\u00a0tlak vody je shodn\u00fd s\u00a0tlakem ve\u00a0sledovan\u00e9 zvodni.\u00a0Hladina vody v\u00a0sond\u00e1ch nespl\u0148uj\u00edc\u00edch v\u00fd\u0161e uveden\u00e9 vlastnosti pozorovac\u00edho vrtu nemus\u00ed odpov\u00eddat hladin\u011b podzemn\u00ed vody ve\u00a0sledovan\u00e9m kolektoru.<\/p>\n

Hydraulika sondy<\/h2>\n

Pokud nen\u00ed sonda dob\u0159e hydraulicky propojena s\u00a0kolektorem, m\u016f\u017ee se zm\u011bna hladiny projevit v\u00a0sond\u011b se zpo\u017ed\u011bn\u00edm. Nemus\u00ed ani doj\u00edt k\u00a0\u00fapln\u00e9mu vyrovn\u00e1n\u00ed hladiny podzemn\u00ed vody a\u00a0hladiny v\u00a0sond\u011b, a\u00a0z\u016fstane trval\u00fd rozd\u00edl. Tento jev je dob\u0159e patrn\u00fd p\u0159i \u010derpac\u00ed zkou\u0161ce, n\u011bkdy se po\u00a0\u010derp\u00e1n\u00ed hladina ust\u00e1l\u00ed na\u00a0m\u00edrn\u011b odli\u0161n\u00e9 \u00farovni ne\u017e p\u0159ed zkou\u0161kou, ta m\u016f\u017ee b\u00fdt ni\u017e\u0161\u00ed i\u00a0vy\u0161\u0161\u00ed ne\u017e v\u00fdchoz\u00ed stav.\u00a0Zpo\u017ed\u011bn\u00ed zm\u011bny hladiny vody v\u00a0sond\u011b nastane tak\u00e9 v\u00a0p\u0159\u00edpad\u011b objemn\u011bj\u0161\u00ed sondy v\u00a0kolektoru s\u00a0malou propustnost\u00ed.<\/p>\n

V\u00a0p\u0159\u00edpad\u011b hydraulick\u00e9ho propojen\u00ed dvou nebo v\u00edce kolektor\u016f sondou a\u00a0pr\u016ftoku vody mezi kolektory je prakticky nemo\u017en\u00e9 p\u0159esn\u011b ur\u010dit vztah hladiny v\u00a0sond\u011b k\u00a0tlaku v\u00a0kolektorech. Takovou sondu je mo\u017en\u00e9 pou\u017e\u00edt k\u00a0zji\u0161t\u011bn\u00ed zm\u011bn celkov\u00fdch bilan\u010dn\u00edch pom\u011br\u016f, ale nelze ji pou\u017e\u00edt k\u00a0zji\u0161t\u011bn\u00ed skute\u010dn\u00e9 \u00farovn\u011b hladiny podzemn\u00ed vody. Sonda m\u016f\u017ee ovliv\u0148ovat pom\u011bry kolektor\u016f trval\u00fdm propojen\u00edm a\u00a0pr\u016ftokem vody mezi kolektory s\u00a0odpov\u00eddaj\u00edc\u00ed zm\u011bnou tlaku (hladiny) nebo do\u010dasn\u011b p\u0159i vytvo\u0159en\u00ed nebo z\u00e1niku statick\u00e9 z\u00e1soby vody. Jev byl pozorov\u00e1n u\u00a0n\u011bkter\u00fdch vrt\u016f, kdy po\u00a0z\u0159\u00edzen\u00ed vrtu hladina po\u00a0ur\u010ditou dobu (i\u00a0n\u011bkolik let) vykazovala trvalou klesaj\u00edc\u00ed nebo stoupaj\u00edc\u00ed tendenci.<\/p>\n

Pneumatika sondy<\/h2>\n

K\u00a0p\u0159enosu barometrick\u00e9ho tlaku do\u00a0vzduchu v\u00a0sond\u011b je pot\u0159eba dobr\u00e9 propojen\u00ed sondy s\u00a0atmosf\u00e9rou. Odv\u011btr\u00e1vac\u00ed otvor sondy mus\u00ed b\u00fdt dostate\u010dn\u00fd k\u00a0rychl\u00e9mu p\u0159enesen\u00ed zm\u011bny tlaku do\u00a0cel\u00e9ho objemu vzduchu v\u00a0sond\u011b. Pokud je sonda \u010d\u00e1ste\u010dn\u011b ut\u011bsn\u011bna od\u00a0atmosf\u00e9ry, zm\u011bna tlaku se projev\u00ed se zpo\u017ed\u011bn\u00edm. Pokud je ut\u011bsn\u011bna zcela, tlak vody p\u016fsob\u00ed proti tlaku stla\u010dovan\u00e9ho vzduchu v\u00a0sond\u011b a\u00a0pohyb hladiny je men\u0161\u00ed ne\u017e v\u00a0otev\u0159en\u00e9 sond\u011b.<\/p>\n

V\u00a0p\u0159\u00edpad\u011b, kdy sonda propoj\u00ed nesaturovanou z\u00f3nu kolektoru s\u00a0atmosf\u00e9rou (u\u00a0vrtu perforace pa\u017enice nad \u00farovn\u00ed hladiny), a\u00a0v\u00a0kolektoru je pro vzduch propustn\u00e9 horninov\u00e9 prost\u0159ed\u00ed, zv\u011bt\u0161uje se objem vzduchu pot\u0159ebn\u00fd k\u00a0p\u0159enesen\u00ed zm\u011bny barometrick\u00e9ho tlaku do\u00a0sondy (vrty, ze kter\u00fdch p\u0159i n\u00edzk\u00e9m barometrick\u00e9m tlaku trvale unik\u00e1 vzduch, a\u00a0p\u0159i vysok\u00e9m tlaku je vzduch nas\u00e1v\u00e1n). Barometrick\u00fd tlak m\u016f\u017ee v\u00a0takov\u00e9 sond\u011b p\u016fsobit p\u0159\u00edmo na\u00a0kolektor a\u00a0m\u011bnit v\u00a0n\u011bm tlakov\u00e9 pom\u011bry. Zvode\u0148 s\u00a0napjatou hladinou se v\u00a0okol\u00ed sondy m\u016f\u017ee zm\u011bnit na\u00a0zvode\u0148 s\u00a0volnou hladinou.<\/p>\n

P\u0159i spln\u011bn\u00ed v\u00fd\u0161e uveden\u00fdch parametr\u016f pozorovac\u00edho vrtu p\u016fsob\u00ed zm\u011bna barometrick\u00e9ho tlaku vzduchu na\u00a0vodn\u00ed hladinu v\u00a0sond\u011b okam\u017eit\u011b, ale v\u00a0kolektoru je odezva podle typu a\u00a0hloubky kolektoru r\u016fzn\u00e1. V\u00a0otev\u0159en\u00fdch kolektorech je p\u016fsoben\u00ed barometrick\u00e9ho tlaku na\u00a0zvode\u0148 rychl\u00e9. Podle stupn\u011b izolace kolektoru se p\u016fsoben\u00ed barometrick\u00e9ho tlaku zmen\u0161uje a\u00a0prodlu\u017euje se \u010dasov\u00e1 odezva, a\u017e ke\u00a0kolektor\u016fm zcela izolovan\u00fdm od\u00a0atmosf\u00e9ry. Zm\u011bna barometrick\u00e9ho tlaku se v\u00a0otev\u0159en\u00fdch m\u011blk\u00fdch kolektorech p\u0159en\u00e1\u0161\u00ed ke\u00a0zvodni p\u016fdn\u00edm vzduchem, v\u00a0\u010d\u00e1ste\u010dn\u011b izolovan\u00fdch kolektorech vzduchem a\u00a0plyny v\u00a0horninov\u00e9m prost\u0159ed\u00ed a\u00a0hydraulicky.<\/p>\n

Dojde-li ke\u00a0zm\u011bn\u011b pom\u011bru tlak\u016f vody a\u00a0vzduchu v\u00a0sond\u011b, zm\u011bn\u00ed se \u00farove\u0148 hladiny. Citlivost hladiny na\u00a0zm\u011bnu barometrick\u00e9ho tlaku lze podle [1] jednodu\u0161e popsat pr\u016fm\u011brnou hodnotou pom\u011br\u016f zm\u011bn hladiny ke\u00a0zm\u011bn\u00e1m tlaku vzduchu BE (barometric efficiency).<\/p>\n

BE = (\u2211 (dHi\/dPi))\/n<\/p>\n

kde dHi je zm\u011bna \u00farovn\u011b hladiny [m] v\u00a0\u010dasov\u00e9m intervalu opakov\u00e1n\u00ed m\u011b\u0159en\u00ed T, dPi je zm\u011bna barometrick\u00e9ho tlaku [mH2<\/sub>O] v\u00a0\u010dasov\u00e9m intervalu opakov\u00e1n\u00ed m\u011b\u0159en\u00ed T (1\u2008kPa = 0,10197 mH2<\/sub>O), n je po\u010det posuzovan\u00fdch zm\u011bn.<\/p>\n

Pro v\u00fdpo\u010det je mo\u017en\u00e9 pou\u017e\u00edt pouze m\u011b\u0159en\u00ed p\u0159i zm\u011bn\u011b barometrick\u00e9ho tlaku. Vztah mezi zm\u011bnou hladiny a\u00a0zm\u011bnou barometrick\u00e9ho tlaku lze tak\u00e9 posoudit vynesen\u00edm hodnot dH a\u00a0dP do\u00a0grafu, v\u00a0kter\u00e9m hodnota BE odpov\u00edd\u00e1 sklonu prolo\u017een\u00e9 line\u00e1rn\u00ed regresn\u00ed funkce. Na\u00a0obr.\u00a01<\/em> je grafick\u00e9 vynesen\u00ed z\u00e1vislosti zm\u011bny hladiny vody na\u00a0zm\u011bn\u011b tlaku vzduchu pro vrt V-28 p\u0159i intervalu m\u011b\u0159en\u00ed 1\u00a0hodina. Vrt V-28 Bu\u010dnice u\u00a0Teplic nad Metuj\u00ed sleduje p\u00edskovcov\u00fd kolektor v\u00a0hloubce 160\u2013240\u2008m a\u00a0s\u00a0hladinou kolem 15\u2008m pod ter\u00e9nem.<\/p>\n\"kasparek-3\"<\/a>\n

Obr.\u00a02. Vrt V-28 Bu\u010dnice, pr\u016fb\u011bh BE pro interval 1\u201310 hod
\nFig. 2. Well V-28 Bucnice, course BE for interval 1\u201310 h<\/h6>\n

Podle zku\u0161enost\u00ed a\u00a0proveden\u00fdch anal\u00fdz je interval m\u011b\u0159en\u00ed T pro zji\u0161t\u011bn\u00ed m\u00edry citlivosti \u00farovn\u011b hladiny na\u00a0zm\u011bny barometrick\u00e9ho tlaku vhodn\u00e9 zvolit v\u00a0rozmez\u00ed deset minut a\u017e jedna hodina. Celkov\u00e1 doba m\u011b\u0159en\u00ed by m\u011bla b\u00fdt nejm\u00e9n\u011b jeden m\u011bs\u00edc, l\u00e9pe je vyhodnotit cel\u00fd hydrologick\u00fd rok. Pro zp\u0159esn\u011bn\u00ed je mo\u017en\u00e9 vy\u0159adit obdob\u00ed v\u00fdznamn\u011bj\u0161\u00edch dotac\u00ed z\u00e1sob podzemn\u00ed vody.<\/p>\n

Hodnota BE se p\u0159i zm\u011bn\u011b doby intervalu m\u011b\u0159en\u00ed T m\u011bn\u00ed, pr\u016fb\u011bh t\u00e9to zm\u011bny m\u016f\u017ee doplnit informace o\u00a0vztahu sondy a\u00a0kolektoru. Na\u00a0obr.\u00a0<\/em>2 je hodnota BE pro vrt V-28 vynesena v\u00a0z\u00e1vislosti na\u00a0d\u00e9lce intervalu m\u011b\u0159en\u00ed T.<\/p>\n

Interpretace hodnot BE<\/h2>\n

B\u011b\u017en\u00e1 hodnota BE je v\u00a0rozmez\u00ed 0 a\u017e -1.\u00a0Hodnoty BE nulov\u00e9 nebo bl\u00edzk\u00e9 nule se vyskytuj\u00ed p\u0159edev\u0161\u00edm u\u00a0m\u011blk\u00fdch zvodn\u00ed s\u00a0volnou hladinou, tj.\u00a0ve\u00a0svrchn\u00edch kolektorech neizolovan\u00fdch od\u00a0atmosf\u00e9ry, kde se zm\u011bna barometrick\u00e9ho tlaku projev\u00ed v\u00a0kolektoru okam\u017eit\u011b. U\u00a0hloub\u011bji sledovan\u00fdch hladin m\u016f\u017ee nulov\u00e1 hodnota BE ukazovat na\u00a0statickou z\u00e1sobu vody v\u00a0sond\u011b, kter\u00e1 nem\u00e1 souvislost s\u00a0vodou podzemn\u00ed. V\u011bt\u0161\u00ed absolutn\u00ed hodnota BE se vyskytuje u\u00a0napjat\u00fdch zvodn\u00ed a\u00a0hloub\u011bji ulo\u017een\u00fdch kolektor\u016f.<\/p>\n

Kles\u00e1-li absolutn\u00ed hodnota BE s\u00a0prodlu\u017euj\u00edc\u00edm se intervalem m\u011b\u0159en\u00ed T, jde o\u00a0kolektor jen \u010d\u00e1ste\u010dn\u011b propojen\u00fd s\u00a0atmosf\u00e9rou, a\u00a0zm\u011bna barometrick\u00e9ho tlaku se v\u00a0kolektoru projevuje se zpo\u017ed\u011bn\u00edm. U\u00a0kolektor\u016f v\u00edce izolovan\u00fdch od\u00a0atmosf\u00e9ry kles\u00e1 absolutn\u00ed hodnota BE pomalu a\u00a0ovlivn\u011bn\u00ed hladiny v\u00a0sond\u011b zm\u011bnou barometrick\u00e9ho tlaku je v\u00fdrazn\u011bj\u0161\u00ed.<\/p>\n

Jestli\u017ee absolutn\u00ed hodnota BE je mal\u00e1, p\u0159i kr\u00e1tk\u00e9m intervalu T a\u00a0p\u0159i jeho prodlou\u017een\u00ed se zv\u011bt\u0161uje, nazna\u010duje to malou hydraulickou propustnost hornin kolektoru nebo \u0161patn\u00e9 propojen\u00ed sondy s\u00a0kolektorem. Je t\u0159eba del\u0161\u00ed doba k\u00a0v\u00fdm\u011bn\u011b vody mezi sondou a\u00a0kolektorem.\u00a0P\u0159\u00ed\u010dinou kladn\u00e9 hodnoty BE m\u016f\u017ee b\u00fdt od\u00a0atmosf\u00e9ry ut\u011bsn\u011bn\u00e9 zhlav\u00ed vrtu u\u00a0zvodn\u011bn\u00ed s\u00a0volnou hladinou podzemn\u00ed vody.\u00a0Chyba m\u011b\u0159en\u00ed zp\u016fsoben\u00e1 zanedb\u00e1n\u00edm vlivu atmosf\u00e9rick\u00e9ho tlaku\u00a0Maxim\u00e1ln\u00ed pohyb hladiny zp\u016fsoben\u00fd vlivem zm\u011bny barometrick\u00e9ho tlaku maxdHp odpov\u00edd\u00e1 sou\u010dinu maxim\u00e1ln\u00edho rozd\u00edlu hodnot barometrick\u00e9ho tlaku maxdP a\u00a0citlivosti BE.<\/p>\n

maxdHp = |BE| . maxdP<\/p>\n

Z\u00a0m\u011b\u0159en\u00ed barometrick\u00e9ho tlaku na\u00a0r\u016fzn\u00fdch m\u00edstech \u010cesk\u00e9 republiky v\u00a0obdob\u00ed 2012\u20132015 bylo vyhodnoceno maxim\u00e1ln\u00ed rozp\u011bt\u00ed kol\u00eds\u00e1n\u00ed barometrick\u00e9ho tlaku (p\u0159i vy\u0159azen\u00ed 10\u00a0% krajn\u00edch hodnot) maxdP = 0,25\u2008m. Zjednodu\u0161en\u011b tedy maxdHp = |BE| . 0,25.<\/p>\n\"kasparek-4\"<\/a>\n

Obr.\u00a03. Vrt V-28 Bu\u010dnice, pozorovan\u00fd pr\u016fb\u011bh hladiny H a\u00a0modelovan\u00e9 kol\u00eds\u00e1n\u00ed hladiny vlivem zm\u011bn tlaku vzduchu Hm pro rok 2013
\nFig. 3. Well V-28 Bucnice, observation of the levels H and modeled level fluctuations due to changes in air pressure, 2013<\/h6>\n

Pro hydrogeologick\u00e9 vrty sleduj\u00edc\u00ed hloub\u011bji polo\u017een\u00e9 kolektory jsou b\u011b\u017en\u00e9 hodnoty BE kolem -0,5. Pokud nem\u00e1me k\u00a0dispozici m\u011b\u0159en\u00ed barometrick\u00e9ho tlaku, resp. zji\u0161t\u011bnou hodnotu BE, m\u016f\u017eeme p\u0159edpokl\u00e1dat pohyb hladiny vlivem zm\u011bn barometrick\u00e9ho tlaku p\u0159ibli\u017en\u011b 0,12\u2008m. Ze stejn\u00e9ho d\u016fvodu je doporu\u010deno ve\u00a0studii [1] p\u0159i \u010derpac\u00ed zkou\u0161ce sn\u00ed\u017eit hladinu nejm\u00e9n\u011b o\u00a00,2\u2008m.<\/p>\n

Z\u00a0praktick\u00e9ho hlediska je d\u016fle\u017eit\u00e9, v\u00a0jak\u00e9m pom\u011bru jsou zm\u011bny hladiny zp\u016fsoben\u00e9 zm\u011bnami tlaku vzduchu k\u00a0celkov\u00e9mu kol\u00eds\u00e1n\u00ed hladiny. Jako m\u011b\u0159\u00edtko m\u016f\u017eeme pou\u017e\u00edt pom\u011br D [%], kter\u00fd p\u0159edstavuje maxim\u00e1ln\u00ed chybu m\u011b\u0159en\u00ed hladiny, kter\u00e9 se m\u016f\u017eeme dopustit zanedb\u00e1n\u00edm vlivu zm\u011bn atmosf\u00e9rick\u00e9ho tlaku.<\/p>\n

D = maxdHp\/maxdH x 100<\/p>\n

kde maxdH je rozsah kol\u00eds\u00e1n\u00ed hladiny v\u00a0sond\u011b a\u00a0maxdHp je rozsah kol\u00eds\u00e1n\u00ed hladiny v\u00a0sond\u011b zp\u016fsoben\u00fd zm\u011bnou atmosf\u00e9rick\u00e9ho tlaku.<\/p>\n

Pro posouzen\u00ed vlivu chyby m\u011b\u0159en\u00ed zp\u016fsoben\u00e9 citlivost\u00ed na\u00a0barometrick\u00fd tlak je vhodn\u00e9 porovnat skute\u010dn\u00fd pr\u016fb\u011bh hladiny s\u00a0modelovou \u0159adou z\u00edskanou ze zm\u011b\u0159en\u00fdch hodnot barometrick\u00e9ho tlaku a\u00a0hodnoty BE. Na\u00a0obr.\u00a03<\/em> a\u00a04<\/em> je skute\u010dn\u00fd pr\u016fb\u011bh hladiny H a\u00a0modelov\u00fd pr\u016fb\u011bh Hm pro vrty V-28 a\u00a0HM-1.<\/p>\n

U\u00a0vrtu V-28 je patrn\u00fd pohyb hladiny vlivem zm\u011bn barometrick\u00e9ho tlaku, kter\u00fd pouze moduluje celkov\u00fd pr\u016fb\u011bh hladiny. Tomu odpov\u00edd\u00e1 pom\u011brn\u011b mal\u00e1 mo\u017en\u00e1 chyba v\u00a0m\u011b\u0159en\u00ed D = 4\u00a0%.\u00a0Vrt HM-1 je krajn\u00edm p\u0159\u00edpadem, kde pohyb hladiny vlivem zm\u011bn barometrick\u00e9ho tlaku je dominantn\u00ed. Maxim\u00e1ln\u00ed mo\u017en\u00e1 chyba v\u00a0m\u011b\u0159en\u00ed zde dosahuje a\u017e D = 40\u00a0%. P\u0159i ob\u010dasn\u00e9m nebo pravideln\u00e9m bodov\u00e9m m\u011b\u0159en\u00ed hladiny v\u00a0del\u0161\u00edch \u010dasov\u00fdch intervalech je tedy t\u0159eba zv\u00e1\u017eit vliv t\u00e9to chyby, pop\u0159.\u00a0upravit re\u017eim pozorov\u00e1n\u00ed.<\/p>\n\"kasparek-5\"<\/a>\n

Obr.\u00a04. Vrt HM-1 M\u011bcholupy, pozorovan\u00fd pr\u016fb\u011bh hladiny H a\u00a0modelovan\u00e9 kol\u00eds\u00e1n\u00ed hladiny vlivem zm\u011bn tlaku vzduchu Hm v\u00a0obdob\u00ed 3. 2012\u201312. 2012
\nFig. 4. Well HM-1 Mecholupy, observation of the levels H and modeled level fluctuations due to changes in air pressure, 3. 2012\u201312. 2012<\/h6>\n

P\u0159\u00edklady r\u016fzn\u00fdch objekt\u016f s\u00a0charakteristick\u00fdm BE<\/h2>\n

D\u016fln\u00ed d\u00edlo Ejpovice u\u00a0Rokycan, ra\u017een\u00e9 v\u00a0pevn\u00e9 b\u0159idlici (Barrandien), hladina p\u0159ibli\u017en\u011b ve\u00a020\u2008m pod ter\u00e9nem, ov\u011b\u0159ov\u00e1na mo\u017enost pou\u017eit\u00ed jako vodn\u00edho zdroje. Hladina zcela stabiln\u00edho pr\u016fb\u011bhu, hodnota BE = 0. \u010cerpac\u00ed zkou\u0161kou bylo prok\u00e1z\u00e1no, \u017ee jde o\u00a0statickou z\u00e1sobu vody nepropojenou s\u00a0\u017e\u00e1dn\u00fdm kolektorem, dotovanou ob\u010dasn\u00fdm p\u0159\u00edtokem z\u00a0nadlo\u017e\u00ed.<\/p>\n

M\u011blk\u00e1 studna na\u00a0h\u0159bitov\u011b v\u00a0Kn\u011b\u017eevsi u\u00a0Rakovn\u00edka, zd\u011bn\u00e1 kamenem, hladina\u00a0p\u0159ibli\u017en\u011b 6\u2008m pod ter\u00e9nem. Hodnota BE = -0,04 (T 1 hod). Studna ve\u00a0svrchn\u00edm kvartern\u00edm kolektoru se zvodn\u00ed dotovanou sr\u00e1\u017ekami. Maxim\u00e1ln\u00ed chyba m\u011b\u0159en\u00ed vlivem barometrick\u00e9ho tlaku D = 0,3\u00a0% celkov\u00e9ho rozp\u011bt\u00ed kol\u00eds\u00e1n\u00ed.<\/p>\n

Pozorovac\u00ed vrt V-28 Bu\u010dnice u\u00a0Teplic nad Metuj\u00ed, hladina p\u0159ibli\u017en\u011b 15\u2008m pod ter\u00e9nem, sleduj\u00edc\u00ed turonsk\u00fd kolektor v\u00a0p\u00edskovci, v\u00a0hloubce 160\u2013240\u2008m [2]. BE pro interval T 1 hod je -0,68 a\u00a0d\u00e1le m\u00edrn\u011b kles\u00e1, viz\u00a0obr.\u00a02<\/em>. Napjat\u00e1 zvode\u0148 je v\u00edce izolovan\u00e1 od\u00a0atmosf\u00e9ry s\u00a0v\u00fdrazn\u00fdm re\u017eimov\u00fdm chodem hladiny (obr.\u00a03<\/em>). Maxim\u00e1ln\u00ed chyba m\u011b\u0159en\u00ed vlivem barometrick\u00e9ho tlaku je D = 4\u00a0% celkov\u00e9ho rozp\u011bt\u00ed kol\u00eds\u00e1n\u00ed.<\/p>\n

Hydrogeologick\u00fd vrt HM-1 u\u00a0M\u011bcholup u\u00a0\u017datce, hladina p\u0159ibli\u017en\u011b 34\u2008m pod ter\u00e9nem, sleduj\u00edc\u00ed kolektor v\u00a0cenomansk\u00fdch p\u00edskovc\u00edch v\u00a0hloubce 35\u2013120\u2008m [3]. Hodnota citlivosti BE je -0,41 pro interval m\u011b\u0159en\u00ed v\u00a0rozmez\u00ed T 1\u201348 hod. Napjat\u00e1 zvode\u0148 izolovan\u00e1 od\u00a0atmosf\u00e9ry s\u00a0pomal\u00fdm re\u017eimem chodu hladiny. Maxim\u00e1ln\u00ed chyba m\u011b\u0159en\u00ed vlivem barometrick\u00e9ho tlaku je D = 40\u00a0% celkov\u00e9ho rozp\u011bt\u00ed kol\u00eds\u00e1n\u00ed.<\/p>\n

Z\u00e1v\u011br<\/h2>\n

Na\u00a0hladinu vody v\u00a0sond\u00e1ch do\u00a0svrchn\u00edch kolektor\u016f s\u00a0volnou hladinou podzemn\u00ed vody maj\u00ed zm\u011bny barometrick\u00e9ho tlaku zanedbateln\u00fd vliv.<\/p>\n

U\u00a0sond sleduj\u00edc\u00edch napjat\u00e9 zvodn\u011b a\u00a0sond do\u00a0hloub\u011bji ulo\u017een\u00fdch kolektor\u016f se zvodn\u011bmi napjat\u00fdmi i\u00a0voln\u00fdmi je patrn\u00fd vliv barometrick\u00e9ho tlaku na\u00a0hladinu, kter\u00fd lze statisticky vyj\u00e1d\u0159it citlivost\u00ed BE. D\u016fsledkem zanedb\u00e1n\u00ed vlivu barometrick\u00e9ho tlaku doch\u00e1z\u00ed ke\u00a0zv\u011bt\u0161en\u00ed chyb m\u011b\u0159en\u00ed \u00farovn\u011b podzemn\u00ed vody v\u00a0kolektoru sondou. Krom\u011b chyby m\u011b\u0159en\u00ed hladiny m\u016f\u017ee b\u00fdt pohyb hladiny v\u00a0sond\u011b vlivem zm\u011bny barometrick\u00e9ho tlaku myln\u011b pova\u017eov\u00e1n za\u00a0skute\u010dnou zm\u011bnu tlaku ve\u00a0zvodni. Pokles tlaku p\u0159i p\u0159echodu front\u00e1ln\u00edho syst\u00e9mu zp\u016fsob\u00ed rychl\u00fd n\u00e1r\u016fst hladiny, kter\u00fd nab\u00edz\u00ed chybnou interpretaci dotace zvodn\u011b sr\u00e1\u017ekami. Podobnost \u010di shodnost pr\u016fb\u011bhu hladiny vlivem zm\u011bn barometrick\u00e9ho tlaku v\u00a0r\u016fzn\u00fdch objektech m\u016f\u017ee v\u00e9st k\u00a0chybn\u00e9mu z\u00e1v\u011bru sledov\u00e1n\u00ed stejn\u00e9 zvodn\u011b.<\/p>\n

Dal\u0161\u00ed mo\u017enosti vyu\u017eit\u00ed znalosti citlivosti hladiny v\u00a0sond\u011b na\u00a0barometrick\u00fd tlak:<\/p>\n

    \n
  • pokud je kolektor sledov\u00e1n vhodn\u00fdm pozorovac\u00edm vrtem, je mo\u017en\u00e9 z\u00a0anal\u00fdzy BE z\u00edskat dopl\u0148uj\u00edc\u00ed informace o\u00a0kolektoru;<\/li>\n
  • p\u0159i sledov\u00e1n\u00ed kolektoru sondou nezn\u00e1m\u00fdch nebo nevhodn\u00fdch parametr\u016f lze rozborem hodnoty BE up\u0159esnit vztah sondy a\u00a0kolektoru;<\/li>\n
  • p\u0159i\u00a0odb\u011bru vzorku podzemn\u00ed vody ze sondy citliv\u00e9 na\u00a0zm\u011bnu barometrick\u00e9ho tlaku napom\u00e1h\u00e1 proud\u011bn\u00ed vody mezi sondou a\u00a0zvodn\u00ed zp\u016fsoben\u00e9 pohybem hladiny k\u00a0v\u00fdm\u011bn\u011b vody v\u00a0sond\u011b.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

    The article deals with the influence of barometric pressure changes on water levels in monitoring wells and other groundwater observation boreholes. An analysis of the problems involved in measuring the groundwater level was performed. <\/p>\n","protected":false},"author":8,"featured_media":1509,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[86],"tags":[307,308,306],"coauthors":[240],"class_list":["post-1586","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-hydraulics-hydrology-and-hydrogeology","tag-barometric-pressure","tag-groundwater","tag-observation-wells"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/1586","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/comments?post=1586"}],"version-history":[{"count":2,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/1586\/revisions"}],"predecessor-version":[{"id":30308,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/1586\/revisions\/30308"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media\/1509"}],"wp:attachment":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media?parent=1586"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/categories?post=1586"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/tags?post=1586"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/coauthors?post=1586"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}