View source for Idrijca

{{for|the border river between Italy and Slovenia|Idrija (river)}}
{{Infobox river
| name              = Idrijca
| name_other        = 
| image             = Idrijca1.JPG
| image_caption     = The Idrijca near the [[Wild Lake]]
| source1_location  = 
| source1_coordinates= 
| mouth_location    = [[Soča]]
| mouth_coordinates = {{coord|46.1517|13.7404|region:SI|display=inline,title}}
| progression       = {{RSoča}}
| subdivision_type1 = Country
| subdivision_name1 = [[Slovenia]]
| length            = {{convert|60|km|mi|abbr=on}} {{GeoQuelle|SI|SURS}}  
| source1_elevation = 
| discharge1_avg    = 
| basin_size        = {{convert|598|km2|sqmi|abbr=on}} {{GeoQuelle|SI|SURS}}
| map = {{infobox mapframe | stroke-color = #0000ff | zoom = 9 }}
}}
[[File:Idrijca4.JPG|thumb|right|200px|The upper Idrijca River]]
[[File:Klavze-Idrijca.JPG|thumb|right|200px| Logging [[sluice]] near [[Idrija]]]]
The '''Idrijca''' is a [[river]] flowing through the [[Idrija Hills]] and [[Cerkno Hills]] in [[Slovenia]]. It is {{convert|60|km}} long.{{GeoQuelle|SI|SURS}} It rises near [[Vojsko, Idrija|Vojsko]], flows towards northeast and after passing through [[Idrija]] turns to the northwest. After passing through [[Spodnja Idrija]] and [[Cerkno]] it joins the [[Soča]] in [[Most na Soči]]. It has a [[pluvio-nival regime]] and belongs to the [[Adriatic Sea]] Basin.<ref>{{cite journal |last=Brečko Grubar |first=Valentina |last2=Kovačič |first2=Gregor |year=2010 |title=Pokrajinskoekološka oznaka jadranskega povodja v Sloveniji s poudarkom na kakovosti vodnih virov |language=Slovenian|trans-title=Landscape Ecological Characterization of the Adriatic Sea Basin in Slovenia with an Emphasis on Water Resource Quality |journal=Annales. Series historia et sociologia |volume=20 |issue=1 |pages=153–168 |url=http://www.dlib.si/details/URN:NBN:SI:DOC-W1WKCHLJ/?}}</ref>

==Hydrogeochemical features==

The Idrijca drains a 624&nbsp;km<sup>2</sup> [[drainage basin|basin]] on the southwestern flank of the [[Julian Alps]]. It rises on the Vojsko Plateau ({{langx|sl|Vojskarska planota}}) at about 924&nbsp;m [[height above mean sea level|ASL]] and flows northeast through Idrija before turning northwest toward its [[confluence]] with the [[Soča]] at [[Most na Soči]]. Owing to exceptionally high precipitation (2,400–5,200&nbsp;mm per year) on the [[windward]] slopes of the [[Alps]] and seasonal snowmelt, the Idrijca exhibits a pluvio-nival [[discharge regime]]: streamflow peaks occur in November (rain plus snowmelt) and again in April, with sustained low flows in summer. Mean long-term [[discharge (hydrology)|discharge]] at the Hotešk gauge is 33.6 cubic metres per second (m<sup>3</sup>/s), ranging seasonally from 3.4–8.5&nbsp;m<sup>3</sup>/s at the low end to 113–644&nbsp;m<sup>3</sup>/s at the high end.<ref name="Kanduc 2008"/>

Beneath its course the Idrijca traverses a complex [[bedrock]] sequence. The upper reaches cut through solid and bedded [[Triassic]] limestone and [[dolomite (mineral)|dolomite]]; the central valley is underlain by Permian [[greywacke]], [[Conglomerate (geology)|conglomerate]], and [[red sandstone]]s; and the lower reaches pass over Triassic dolomite interbedded with [[marl]]s and [[Cretaceous]] limestone [[breccia]]. This geology governs the river's chemistry: waters are of the HCO₃⁻–Ca²⁺–Mg²⁺ type, with Ca²⁺/Mg²⁺ molar ratios indicating dominant dolomite [[weathering]], and total [[alkalinity]] typically 3.9–5.1&nbsp;[[molarity|mM]]. Field [[pH]] values range from 7.7 to 8.8, and saturation indices show persistent [[supersaturation|oversaturation]] with respect to [[calcite]] and dolomite, so the Idrijca both dissolves and reprecipitates [[carbonate]] minerals along its course.<ref name="Kanduc 2008"/>

[[Isotope analysis|Isotopic]] and [[mass balance]] studies demonstrate that carbonate [[solvation|dissolution]] is the principal source of [[dissolved inorganic carbon]] (DIC) in the river, supplemented by inputs of soil-derived [[carbon dioxide|CO<sub>2</sub>]] and organic-matter [[decomposition]] in spring, and offset by CO<sub>2</sub> outgassing to the atmosphere. [[pCO2|Partial pressures of CO<sub>2</sub>]] in the water may rise to 13 times [[Atmospheric pressure|atmospheric]], making the Idrijca a net CO<sub>2</sub> emitter. Together, these [[hydrogeochemistry|hydrogeochemical]] characteristics highlight the tight coupling between the basin's geology, climate and [[biogeochemistry|biogeochemical]] processes in shaping both the flow regime and water chemistry of the Idrijca.<ref name="Kanduc 2008"/>

==Tributaries==
{{Div col}}
*[[Senčni potok]] 
*[[Nikova]] 
*[[Kanomljica]] 
*[[Otuška]] 
*[[Sevnica (creek)|Sevnica]] 
*[[Trebuščica]] 
*[[Hotenja]] 
*[[Črni potok]]  
*[[Belca (creek)|Belca]] 
*[[Zala (creek)|Zala]] 
*[[Ljubevščica]] 
*[[Zaspana grapa]]  
*[[Skavnica]] 
*[[Peklenska graba]] 
*[[Grda grapa]] 
*[[Luknjica]] 
*[[Zaganjalčnica]]
*[[Cerknica (creek)|Cerknica]] 
*[[Jesenica]] 
*[[Bukovška grapa]] 
*[[Žibernik]] 
*[[Doberšček]] 
*[[Bača (river)|Bača]]
{{div col end}}

==References==
{{Reflist|refs=

<ref name="Kanduc 2008">{{cite journal |last=Kanduč |first=Tjaša |title=Hydrogeochemical characteristics of the River Idrijca |journal=Geologija |year=2008 |volume=51 |issue=1 |pages=39–49 |doi=10.5474/geologija.2008.004|doi-access=free }}</ref>

}}

==External links==
* {{Commons category-inline|Idrijca}}
* [https://www.geopedia.world/#T12_L362_F3226:58040_x1536343.0124869363_y5799830.567729857_s13_b2345 Idrijca on Geopedia]
* [https://web.archive.org/web/20160304002952/http://www.arso.gov.si/vode/podatki/amp/H15_g_30.html Condition of Idrijca] - graphs, in the following order, of water level and flow for the past 30 days (taken in [[Podroteja]] by [[Slovenian Environment Agency|ARSO]])

{{Hydrology of Slovenia}}
{{Authority control}}

[[Category:Rivers of the Slovene Littoral]]
[[Category:Natura 2000 in Slovenia]]