461:, but unlike most Pas-de-Calais waterways, the Liane exhibits highly marked seasonal fluctuations. High waters occur at the end of autumn and in winter, characterised by monthly mean flow rates between 3.06 and 5.33 mÂł/s, from November to March inclusive with a maximum in January. Low waters occur in summer, from June to September, with a decrease in monthly mean flow rate descending to 0.76 mÂł/s in August. However variations in flow rate are much more pronounced over short periods or from year to year.
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527:. Towns and industries are now polluting less, but ploughing has conquered land from farming and pasture which have been pushed back in this region, and farmland erosion and fields which are kept barren in winter and autumn are a cause of the Liane's almost constant turbidity. In 2005, the Liane remained turbid and its French water quality grade
494:
The maximum instantaneous flow rate recorded at
Hesdigneul-lès-Boulogne during the 2-year measurement period was 47.3 m³/s on 1 December 1979, while the maximum daily average flow rate was 41.6 m³/s on 6 February 1988. Comparing the first of these values to the scale of the IMFR numbers, it
498:
The Liane is a very fast-flowing small river, fed heavily by the high rainfall in its watershed. The watershed runoff curve number is 483 mm annually, which is substantially larger than the average of France based on all its watersheds, as well as, for example, the average for the watershed of
490:
can be very significant considering the modest size of this small river and its watershed. The instantaneous maximal flowrate 2 (IMFR2) and IMFR5 metrics are 37 and 52 mÂł respectively. The IMFR10, or flow rate calculated from the ten-year flood, is 61 mÂł/s, the IMFR20 is 70 mÂł/s and
552:'s association has, through various activities, attempted to make the Liane known other than for its reputation as being highly polluted; while this is true around Boulogne-sur-Mer, there are some places where the Liane is a picturesque river with swarms of fish. The
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which abuts the
Picardy estuaries up to the location of the two capes. It has been proposed in one variation of the project that its estuary, although significantly transformed by technology, should be part of a putative natural park, the
729:
484:
At low water, the 3-year low instantaneous flow rate can drop to 0.066 mÂł/s in the case of a dry five-year period or 66 litres per second, which can be described as severe.
531:(unsatisfactory), with too much nitrates and organic substances from Carly onwards, according to the water agency. At the mouth at Boulogne, the Liane's waters are graded as
480:
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695:
535:(bad), with all the indicators being bad: macro-pollutants, organic and oxidizable substances, azot substances (nitrates) and phosphoric substances.
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724:
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The Liane hosts two hydrometric stations, at
Wirwignes (watershed 100 km²) and Hesdigneul-lès-Boulogne (watershed 196 km²).
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which measures 249 mm at
Wervicq-Sud. The specific flow rate reaches 15.3 litres per second per square kilometre of watershed.
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The Liane is a very fast flowing river, but quite irregular. Its flow rate has been measured over a 27-year period (1965–1991), at
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becomes clear that the 1979 flood was hardly a 5-year event, and thus floods of this size are to be expected very frequently.
447:. The watershed of the river at that point is 196 km², or approximately 80% of its maximum value of 244 km²).
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Mean monthly flow rate of the Liane (in mÂł/s) measured at the
Hesdigneul-lès-Boulogne hydrological station
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560:(known as "farios") to repopulate the river and replace the fish which they have caught.
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The average gradient of the Liane is 2.8 ‰. Its tributaries include the following:
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Banque Hydro – Station E5310210 – The Liane at
Hesdigneul-lès-Boulogne (synthesis)
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Catalogue of water agency analyses for the Artois/Nord/Picardie basin
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Parc naturel marin Ă l'ouvert des estuaires picards et en mer d'Opale
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Banque Hydro – Station E5310210 la Liane à Hesdigneul-lès-Boulogne
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of the Liane at
Hesdigneul-lès-Boulogne is 2.99 m³/s.
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The Liane flows for a length of 38.2 km. It rises at
654:
371:, a proposal in preparation since 2008 and submitted to
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fishermen's association even regularly deposits wild
655:"Association des Pêcheurs de la Vallée de la Liane"
653:Association des Pêcheurs de la Vallée de la Liane.
515:, the Liane's water quality was mediocre to highly
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519:during the years 1980–1990, mainly as a result of
554:Association des Pêcheurs de la Vallée de la Liane
730:Coastal basins of the English Channel in France
346:. It finally flows into the English channel at
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543:Schéma d'Aménagement et de Gestion des Eaux
242:. Other communes along its length include:
689:(do not tick the box "Station en service")
629:(Don't tick the box "Station en service")
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614:"Fiche cours d'eau - La Liane (E53-0020)"
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537:The situation may be improved by the
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208:2.99 m/s (106 cu ft/s)
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450:The mean interannual flow rate or
222:is a 38 km long river in the
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186:244 km (94 sq mi)
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137: • coordinates
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491:the IMFR50 was 82 mÂł/s.
457:Just like its neighbour, the
86:Physical characteristics
698:of the Liane (downloadable)
362:contributed directly to the
715:Rivers of the Pas-de-Calais
681:Société de Pêche de Desvres
350:. Before being fitted with
104: • location
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379:Morphology and tributaries
204: • average
725:Rivers of Hauts-de-France
696:Altlas of floodable zones
545:water management scheme.
539:Water Framework Directive
473:over a period of 27 years
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570:List of rivers of France
443:, a short way from its
437:Hesdigneul-lès-Boulogne
280:Hesdigneul-lès-Boulogne
226:department in northern
178:38 km (24 mi)
35:Hesdigneul-lès-Boulogne
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300:Saint-Étienne-au-Mont
511:Other than near its
541:, and by the local
390:Right tributaries:
364:fleuve marin cĂ´tier
234:and flows into the
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159:50.7317°N 1.5865°E
548:For some years a
507:Ecological status
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658:. Retrieved
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358:, the Liane
328:Questrecques
320:Bournonville
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252:Bournonville
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700:(in French)
691:(in French)
678:(in French)
631:(in French)
525:urban waste
162: /
51:Native name
709:Categories
596:References
521:industrial
416:Menneville
410:Lottinghem
336:Hesdigneul
248:Brunembert
183:Basin size
147:50°43′54″N
550:fishermen
452:discharge
431:Hydrology
400:Echinghem
375:in 2011.
324:Wirwignes
310:Geography
264:Wirwignes
260:Crémarest
256:Alincthun
195:Discharge
150:1°35′11″E
564:See also
533:mauvaise
517:polluted
459:Wimereux
316:Quesques
296:Condette
232:Quesques
109:Quesques
71:Location
56:La Liane
422:Desvres
397:Corette
360:estuary
304:Outreau
76:Country
660:21 May
610:Sandre
513:source
488:Floods
419:l'Edre
352:canals
340:Isques
302:, and
284:Isques
244:Selles
228:France
198:
175:Length
98:
95:Source
80:France
63:French
59:
576:Notes
558:trout
445:mouth
439:near
356:locks
332:Carly
276:Carly
272:Samer
220:Liane
124:Mouth
22:Liane
662:2010
523:and
394:Lamy
354:and
342:and
218:The
128:The
501:Lys
238:at
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61:(
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
