Poplave
Poplave nastanejo zaradi izredno močnih padavin ali naglega taljenja snega ali medsebojnega skupnega delovanja. Do poplav lahko pride tudi zaradi zajezenega odtoka, zaradi zajezitev, ki jih povzročijo snežni ali zemeljski plazovi, zaradi delovanja hudournikov, naravnega posedanja tal ter padavin in istočasnega taljenja snega na zamrznjeni podlagi in s tem dviga gladine. Poplave so lahko tudi posledica človekovih posegov v naravo.
Značilnosti poplav v občini Mozirje
Vodno območje
Porečje Savinje pripada vodnemu območju Save. Porečja sestavljajo večji ali manjši pritoki, ki močno vplivajo na značilnost vodotokov. V občini Mozirje poplavlja Savinja s svojimi pritoki (Mozirnica, Trnava, Ljubija, Škrubov potok).
Rečni režim
Rečni režim je spreminjanje vodnega stanja med letom, kar je predvsem izraz časovne razporeditve padavin, izhlapevanja, zadrževanja podzemnih voda in podobnega. Višek vodnega stanja zato ne sovpada povsod in popolnoma z viškom padavin.
Vodotoki v občini Mozirje imajo snežno-dežni tip rečnega režima. Zanj je značilno, da je primarni višek aprila, lahko marca ali celo maja, sekundarni pa je vedno novembra, nato pa še decembra. Ta režim ima dve različici:
celinsko - sekundarni višek je manj izrazit, obdobje najnižje poletne vode pa traja do septembra.
sredozemsko – običajno se jesenski dežni maksimum združi z marčno-aprilskim, se mu zelo približa ali pa ga celo malenkostno preseže (ta vodni režim je značilen za vodotoke predalpskega hribovja, dinarsko-kraškega sveta in subpanonskega dela Slovenije; ima ga tudi Soča v spodnjem toku).
Poplavno območje, obseg in ogroženost
Glede na povratno dobo nastopa visokih voda ločimo naslednje poplavne linije:
- poplavne linije s povratno dobo nastopa do 5 let - pogoste poplave,
- poplavne linije s povratnimi dobami od 10 do 20 let - 10- do 20- letne poplave,
- poplavne linije s povratno dobo 100 in več let - katastrofalne poplave.
Poplave, s posledicami, ki jih prinašajo poplave s 50 – 100 letno povratno periodo, se pojavljajo že v presledkih, ki so krajši od 10 let.
Skozi jedro Mozirja je Savinja sicer urejena in je pretok zadovoljiv tudi ob večji količini vode. Poplave nastopajo na neurejenem odseku od Mozirja do Letuša in naprej. Te poplavijo nekaj kmetijskih površin in cestno infrastrukturo.
Pri večjih poplavah Savinja in potoki poplavijo naslednje odseke cest, ki so delno ali v celoti neprevozni:
- Mozirje – Ljubija
- Mozirje – Nazarje
- Šmihelska cesta
- javne poti
- lokalne ceste
Na cestiščih in bankinah ter neutrjenih poteh pride do odplavljanja materiala, kar ima za posledico delno ali celotno neprevoznost določenih odsekov posameznih cest.
Ob poplavljenih kmetijskih območjih in cestiščih, pa se zaradi dviga podtalnice pojavlja tudi voda v posameznih objektih v kleteh v neposredni bližini vodotokov. Do poplav pride tudi v objektih, ki nimajo pravilno urejenega odvoda meteornih vod ali so zgrajeni pod nivojem vodostaja ob poplavah. Na podlagi ocene ogroženosti bi bilo ob večjih poplavah potrebno evakuirati cca 30 oseb.
Ogroženih je 70 stanovanjskih hiš, 30 gospodarskih poslopij ter dve gospodarski organizaciji.
Možni vzroki nastanka poplav občini Mozirje
Možni vzroki poplav v občini Mozirje so predvsem naslednji:
- poplave zaradi dolgotrajnega deževja (najpogosteje v jesenskih in spomladanskih mesecih), ko je velika verjetnost, da bo narasla voda reke Savinja preplavila brežine strug;
- razlitja lokalnih potokov: Mozirnica (v katerega se zliva Breznica), Trnava (v katerega se zlivajo Golobnica, Mlinščica in Šumek), Ljubija (v katerega se zlivata Jurkovski graben in Šunc) ter Škrubov potok (v katerega se zlivata Lokovšek in Tripotok). Obstaja tudi možnost poplavljanja v Mozirski strugi in Ločki strugi. Ob morebitnem poplavljanju se pojavlja tudi nevarnost prelivanja tudi Ribnika pri Gaju.
- zaradi silovitih (predvsem poletnih) ploh in nalivov. Gre za nenadne poplave (izrazito hudourniške narave), ko (nevzdrževane) struge potokov ne zmorejo odvesti večjih količin vode, zato se razlijejo po bližnjih površinah.
Najbolj ogrožena poplavna območja:
- Celine – Delejev jez – Savinjski gaj – Loke. Pred 100 letnimi vodami so ogroženi objekti v Savinjskem gaju, 15 stanovanjskih objektov v Lokah in naselje Nove Loke;
- poplavno območje potokov Trnava in Mozirnica. Ogroženih je pribl. 10 stanovanjskih objektov;
- poplavno območje potoka Ljubija. Ogroženih je šest stanovanjskih objektov in nekaj travniških površin.
Verjetnost nastanka verižnih nesreč
Ob poplavah lahko pride do različnih verižnih nesreč:
- preplavitve, zablatenje in zamurjenje travniških in kmetijskih površin,
- nenadzorovano uhajanje nevarnih snovi v okolje – predvsem kurilno olje iz gospodinjstev na poplavnem območju,
- poškodbe infrastrukture - komunalna infrastruktura, mostovi (most na Savinji ter mostovi: Mozirnica 7 mostov, Trnava 5 mostov, Ljubija 7 mostov, Škrabov potok 1 most), cesta Mozirje - Letuš
- kontaminacija pitne vode v centralnem vodovodnem sistemu,
- plazenje zemlje in manjši plazovi.
vir: www.mozirje.si/wp-content/uploads/2017/03/POPLAVE-MOZIRJE.doc
Geologija območja
Severno od reke Savinje prevladujejo kamnine smrekovške serije, za katero je značilno plastovito odlaganje. Značilnost te serije kaže, da so vulkanski izbruhi vzdolž smrekovške prelomnice dali veliko materiala, ki je drsel oziroma se premikal z blatnimi tokovi po pobočju morskega bazena na njegovo dno. Debelina serije je okoli 800 do 1000 m. Največji delež severno od Mozirja predstavljata andezitni tuf in tufit iz obdobja paleogena. Tuf najdemo v treh različicah: - iz plovca, drobcev lave in andezita, - iz vulkanskega stekla, - iz mikrokristalne osnove. V kateri so nalomljeni kristali visokotemperaturnih plagioklazov, ki pripadajo andezinu. Tufit je je navadno laminirana rjavkasto siva kamenina, ki je sestavljena iz zrn plagioklaza, kameninskih drobcev, zrnc kremena, posameznih zrnc glaukonita in mikrokristalne osnove. Vmes se pojavljajo še zrnca stekla, plovca, kremena in kalcita. Severno od Savinje pa se pojavljata tudi masivni kristalasti dolomit iz triasa ter siv apnenec in dolomit iz paleozoika. Južno od Savinje je geološka zgradba pestrejša, saj najdemo apnence, glinaste skrilavce, laporno glinaste skrilavce z vložki breče iz triasa ter tuf iz obdobja paleogena. Geološka karta:
vir:
Naloge za vpis:
1a. Katerega leta je bil izmerjen najvišji nivo vode?
1b. Koliko je znašal izmerjeni nivo vode tega leta?
2. Kolikšen je bil nivo vode leta 1990?
3. Zapiši vsaj dva ukrepa, ki bi jih lahko izvedli za zmanjšanje škode ob poplavah.
4. Oglej si značilnosti pokrajine. S svojimi besedami opiši, kako naravne značilnosti vplivajo na poplave tukaj. Ali misliš, da geologija območja vpliva na pogostost poplav? Pomagaj si s karto na:
Za pridobitev vseh podatkov pojdite od izhodiščnih koordinat preko mostu na desni breg reke ter se sprehodite ob toku navzdol. Kmalu boste našli vodomerno postajo. S tamkajšnjimi podatki bodo odgovori kot na dlani.
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Floods
Floods are caused by extremely heavy rainfall or rapid snowmelt or mutual joint action. The floods may also occur due to dammed runoff, damming caused by snow or landslides, action of mountain streams, natural subsidence of soil and rainfall and due to simultaneous melting of snow on frozen ground what causes raising of water level. Flooding can also be the result of human intervention in nature.
Characteristics of floods in the municipality of Mozirje
Water area
Savinja river basin belongs to the water area of the Sava River. Water areas cover the basin of watercourses, which consists of a water catchment. Catchment areas consist of a greater or smaller tributaries, which greatly affect the characteristics of the streams. In the municipality of Mozirje floods are caused by Savinja and its tributaries (Mozirnica, Trnava, Ljubija, Škrubov stream).
River regime
River regime is changing the water level during the year, which is primarily a reflection of the timing of precipitation, evaporation, keeping the ground water etc. Excess of the water is therefore not always at the same time as peak of rainfall.
Rivers in the municipality of Mozirje have a nivo-pluvial type of river regime. It is characteristic that the primary surplus is in April, March and even May, the secondary is in November, then December. This arrangement has two versions:
- Mainland - secondary peak is less pronounced, the period of low summer water lasts until September.
- Mediterranean - normally the autumn rain maximum is combined with the March-early April, it is very close or even slightly exceeds (the river regime is characteristic for streams of Alpine foothills, Dinaric-karst and Subpannonian part of Slovenia).
Flood area and threatening
According to the return period of occurrence of high water flood distinguish the following lines:
- flood line with the return period of performance up to 5 years - frequent floods,
- flood line with return periods of 10 to 20 years - 10- to 20-year flood,
- flood line with the return period of 100 years or more - catastrophic floods.
< p>![Figure 1: Returning periods of streams and location of Mozirje municipality« src=]()
Floods with the consequences brought by floods with 50-100 year return period are already occurring in intervals shorter than 10 years.
Through Mozirje Savinja has regulated stream and the flow is satisfactory even when there is larger amount of water. Flooding occur where stream is unregulated – at section Mozirje - Letuš and forth. Here some farmland and road infrastructure are flooded.
At major floods Savinja and streams flood following sections of roads that are partially or completely blocked:
- Mozirje – Ljubija,
- Mozirje – Nazarje,
- Šmihelska cesta,
- public paths,
- local roads.
Sediment material is accumulated to roads that are partially or completely blocked at some sections.
Some buildings in the cellars in the vicinity are flooded due to raising of ground water during the floods. The floods also occur in infrastructure that don't have properly regulated sink of rainwater or are built below the water level during floods. On the basis of the threat assessment it would be necessary to evacuate about 30 people during major floods.
Floods threatened 70 houses, 30 outbuildings and 2 commercial organizations.
Possible causes of flooding in municipality Mozirje
Possible causes of floods in the municipality of Mozirje are as follows:
- flooding due to long raining (usually in the autumn and spring months), when is the high probability that it will increase water level in river Savinja;
- when local creeks overflows banks: Mozirnica (with Breznica), Trnava (with Golobnica, Mlinščica and Šumek), Ljubija (with Jurkovski grab and Šunc) and Škrubov stream (with Lokovšek and Tripotok). There is also the possibility of flooding in Mozirska stream and Ločka stream. In the event of flooding, there is also the risk of overflowing Ribnik and Gaj.
- extremely strong (especially summer) rain showers. These are the flash floods (highly torrential nature) when (unmaintained) channel streams are not able to drain large quantities of water, so they overcross banks to the surrounding areas.
Most endangered areas:
- Celine - Delejev dam - Savinjski gaj - Loke. Before 100 years the waters are endangered objects in Savinjski gaj, 15 residential buildings in the village Loke and Nove Loke;
- flood area of streams Trnava and Mozirnica. Threatened approx. 10 residential buildings;
- flood area of Ljubija stream. It threatened six residential buildings and a few meadows.
The probability of accidents chain
Floods can occur variety chains of disasters:
- inundated, soil sealing of grassland and farmland,
- uncontrolled leakage of hazardous substances into the environment - mainly fuel oil from households in the flood area,
- damage to infrastructure - municipal infrastructure, bridges (the Savinja bridge, and bridges: Mozirnica 7 bridges, Trnava 5 bridges, Ljubija 7 bridges, Škrabov creek bridge 1), road Mozirje - Letuš
- contamination of drinking water in the central water supply system,
- major and minor landslides.
Source: www.mozirje.si/wp-content/uploads/2017/03/POPLAVE-MOZIRJE.doc
Geology of the area
North of the river Savinja are mostly rocks of the Smrekovec serie. Serie is characterized by layered deposition. The characteristic of this serie shows that volcanic eruptions along a Smrekovec fault gave a lot of material that glided or moved with muddy currents along the slope of the sea basin to its bottom. The thickness of the serie is about 800 to 1000 m. The largest proportion north of Mozirje is represented by andesite tuff and tufit from the period of paleogene. Tuff is found in three versions: - from the float, fragments of lava and andesite, - from volcanic glass, - from a microcrystalline basis in which crystals of high temperature plagioclases belonging to andezine are fractured. Tufit is usually a laminated brownish gray stone consisting of plagioclase grains, stone fragments, quartz granules, individual glacolite granules and a microcrystalline base. It also consists of granules of glass, float, silica and calcite. The massive crystalline dolomite from the triassic and gray limestone and dolomite from the paleozoic are also located north of the Savinja River. South of the Savinja river, the geological structure is richer, as we find limestone, clay slate, marl clay slate with triassic breast spots and tuff from the period of paleogene Geological map:
source:
- http://biotit.geo-zs.si/ogk100/images/TOLMACI/Ravne_tolmac.pdf
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Tasks for logging:
1a. What year was the highest measured level of water?
1b. What was the highest level of water this year?
2. What was the water level in 1990?
3. Write at least two actions that could reduce the damage during floods.
4. Look around and watch characteristics of landscape. Whith your own words describe, how natural characteristics influence to the floods here. Do you think that geology of the area influence to frequency of floods? Help with map at
To get all answers go from starting coordinates over the bridge and downstream by the river. You will come to station where they measure water level. With that information answers will be easy.
IMPORTANT!
- Send answers through GC profile before logging. After that you can log - you don't need an additional permission to log I will contact you if something is wrong. Please, upload photos if you have taken them.
- Logs without an accompanying e-mail containing correct answers will be encrypted and later deleted!
- Logs containing the answer will be deleted!