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Hydrogeology Journal

, Volume 18, Issue 2, pp 325–337 | Cite as

Depletion risk assessment of the Nossana Spring (Bergamo, Italy) based on the stochastic modeling of recharge

  • Paola Gattinoni
  • Vincenzo Francani
Paper

Abstract

A hydrogeological study of the Nossana Spring (Val Seriana, Bergamo, Italy) is presented with the aim of assessing the spring’s depletion risk. In the last few years, the discharge of the Nossana Spring showed a decreasing trend, similar to the trend of many other springs in the Prealpine Region. The study was carried out using a groundwater flow model to simulate the depletion curve of the spring in different recharge conditions. The simulations have shown that the depletion curve of the Nossana Spring depends on the recharge during the previous season. As a result, a negative exponential relation giving the spring depletion curve as a function of the recharge was obtained. This relation was also used to statistically calculate the actual probability of the occurrence of a deficiency in water resources, which for the present day is equal to 2%. Finally, the effect of climate change was considered, showing in the next 100 years a flat decline of about 40% in the average spring discharge and a considerable shortening of the critical length (the time to reach the critical discharge at which supply problems occur) in the dry season, which will be halved by the end of the century.

Keywords

Karst spring Depletion curve Depletion risk Stochastic modeling Italy 

Evaluation du risque de tarissement de la source Nossana (Bergame, Italie) à partir d’un modèle stochastique de la recharge

Résumé

Une étude hydrogéologique de la source Nossana ( Val de Sériana, Bergame, Italie) est présentée avec pour objectif l’évaluation du risque de tarissement de la source. Au cours des dernières années, le débit de la source Nossana a montré une tendance à la diminution, similaire à la tendance observée pour des nombreuses sources de la région préalpine. L’étude a été menée en ayant recours à un modèle hydrogéologique afin de simuler la courbe de récession de la source pour différentes conditions de recharge. Les simulations ont montré que la courbe de tarissement de la source est influencée par la recharge de la saison précédente. Une relation de type exponentiel négative permet d’expliciter la courbe de récession de la source en fonction de la recharge. Cette relation a été utilisée pour calculer de manière statistique la probabilité d’occurrence d’un déficit de la ressource en eau; celle-ci est équivalente pour le présent à 2%. Enfin, l’effet du changement de climat a été considéré, montrant qu’au cours de cent prochaines années la possibilité d’une diminution de quelques 40% du débit de la source en moyenne et une réduction considérable de la longueur critique (temps pour atteindre le débit critique à partir duquel des problèmes d’alimentation en eau surviennent) en période de sécheresse, soit une division par deux d’ici la fin du siècle.

Stochastisches Auffüllungsmodell zur Bewertung der Absenkungsgefahr der Quelle Nossana (Bergamo, Italien)

Zusammenfassung

Es wird eine hydrogeologische Studie vorgelegt, um die Gefahr der Absenkung der Quelle Nossana (Val Seriana, Bergamo, Italia) zu untersuchen. Schon in den vergangenen Jahren wurde eine Tendenz zur Reduzierung des Wasserflusses beobachtet, die der anderer voralpiner Quellen gleicht. Es wurden mit einem unterirdischen Strömungsmodell die Absenkungsraten der Quelle unter verschiedenen Auffüllungsbedingungen dargestellt, wobei das Verhältnis zwischen der Absenkungskurve der Quelle Nossana und der Auffüllungsrate der Vorjahressaison hervorgehoben wird. Es wurde eine negative Exponentialfunktion entdeckt, mit der sich die Absenkungskurve der Quelle unter Berücksichtigung der Auffüllung bestimmen lässt. Dieses Verhältnis wurde zur statistischen Auswertung herangezogen, um die aktuelle Wahrscheinlichkeitsrate einer hydrologischen Krise herauszufinden, die mit 2 % angegeben wird. Zum Schluss wurden die möglichen Auswirkungen einer Klimaveränderung in den nächsten 100 Jahren unter Berücksichtigung eines Netto-Rückganges (ca. 40%) des durchschnittlichen Abflusses der Quelle und einer erheblichen Reduzierung der kritischen Trockenzeitdauer (im Sinne eines Zeitraumes in dem die Quelle eine kritische Strömungsgeschwindigkeit erreicht, die das von ihr gespeiste Wasserzuführungssystem in Gefahr bringen kann) analysiert, die am Ende des Jahrhunderts halbiert sein wird.

Evaluación del riesgo de depleción del Nossana Spring (Bergamo, Italia) basado en un modelado estocástico de la recarga

Resumen

Se presenta un estudio hidrogeológico del manantial de Nossana (Val Seriana, Bergamo, Italia) con el objetivo de evaluar el riesgo de depleción del manantial. En estos últimos años, la descarga del manantial de Nossana mostró una tendencia decreciente, similar a la tendencia de muchos manantiales en la región pre Alpina. El estudio fue llevado a cabo usando un modelo de flujo de aguas subterráneas para simular la curva de depleción del manantial en diferentes condiciones de recarga. Las simulaciones han mostrado que la curva de depleción del manantial de Nossana depende de la recarga durante la estación previa. Como resultado se obtuvo una relación exponencial negativa que da la curva de depleción del manantial en función de la recarga. Esta relación fue también usada para calcular estadísticamente la probabilidad real de la ocurrencia de una deficiencia en los recursos de agua, la cual actualmente equivale a 2%. Finalmente, se consideraron los efectos del cambio climático en los próximos 100 años, lo cual mostró un descenso parejo de cerca del 40% en la descarga promedio del manantial y una considerable reducción de la longitud crítica (tiempo para alcanzar una descarga crítica en que ocurren los problemas de alimentación) en la estación seca, la cual se verá reducida a la mitad hacia el final del siglo.

基于补给的随机模拟方法评估意大利贝加莫Nossana泉枯竭风险

摘要

为评价其枯竭风险, 对意大利贝加莫Val Seriana城的Nossana泉进行了水文地质研究。在过去的几年, 与Prealpine地区许多其他的泉一样, Nossana泉的排泄量表现出下降的趋势。本次研究通过地下水流模型来模拟不同补给条件下该泉的枯竭曲线。模拟表明, Nossana泉的枯竭曲线取决于前一季节的补给量。由此得到泉的枯竭曲线是补给量的负指数函数。此关系也用于对水资源不足发生的实际概率进行统计计算, 当前概率为2%。最后, 考虑了气候变化的影响, 得出在未来的100年平均泉排泄量有约40%的平缓下降, 以及旱季临界长度 (达到临界排泄量的时间, 即补给问题出现的时间) 的显著缩短, 到本世纪末该长度会减半。

Modellazione stocastica della ricarica per la valutazione del rischio di esaurimento della Sorgente Nossana (Bergamo, Italia)

Riassunto

La nota propone uno studio idrogeologico finalizzato alla valutazione del rischio di esaurimento della Sorgente Nossana (Val Seriana, Bergamo, Italia). Negli ultimi anni, infatti, le portate di questa sorgente hanno evidenziato un tendenza alla decrescita, con un andamento simile a quello di molte altre sorgenti della fascia prealpina. Tramite un modello di flusso sotterraneo si sono simulate le curve di esaurimento della sorgente per diverse condizioni di ricarica, evidenziando la dipendenza dell’andamento della curva di esaurimento della Sorgente Nossana dalla ricarica della stagione precedente. E’ quindi stata individuata una funzione esponenziale negativa in grado di fornire la curva di esaurimento della sorgente in funzione proprio della ricarica. Tale relazione è poi stata utilizzata per valutare in termini statistici l’attuale probabilità di accadimento di un periodo di crisi idrica, risultata pari al 2%. Infine, si sono analizzati i possibili effetti derivanti dal cambiamento climatico, evidenziando per i prossimi 100 anni una decrescita netta (pari a circa il 40%) della portata media della sorgente e una notevole riduzione della durata critica della stagione asciutta (intesa come il periodo di tempo tale per cui la sorgente raggiunge una portata critica, cioè in grado di mandare in crisi il sistema acquedottistico da essa alimentato), che arriverà a dimezzarsi per la fine del secolo.

Avaliação do risco de esgotamento da nascente Nossana (Bérgamo, Itália) com base na modelação estocástica da recarga

Resumo

Apresenta-se o estudo hidrogeológico da nascente Nossana (Val Seriana, Bérgamo, Itália), com o objectivo de avaliar o risco de esgotamento da nascente. Nos últimos anos, o caudal da nascente Nossana apresenta uma tendência decrescente, similar às tendências de muitas outras nascentes na região Pré-alpina. O estudo foi conduzido recorrendo a um modelo de fluxo de águas subterrâneas para simular a curva de esgotamento da nascente em diferentes condições de recarga. As simulações mostraram que a curva de esgotamento da nascente Nossana depende da recarga durante a estação anterior. Como resultado, obteve-se uma relação exponencial negativa entre a curva de esgotamento da nascente e a recarga. Esta relação foi ainda utilizada para calcular estatisticamente a probabilidade real de ocorrer escassez nos recursos hídricos, que actualmente é de 2%. Finalmente, considerou-se o impacte das alterações climáticas, demonstrando-se que nos próximos 100 anos ocorrerá um declínio gradual de cerca de 40% no caudal médio da nascente e um decréscimo considerável da distância crítica (o tempo necessário para atingir o caudal crítico, em que podem ocorrer problemas no abastecimento) durante a época seca, que será reduzida para metade até ao final do século.

Notes

Acknowledgements

The authors would like to acknowledge both the reviewers and the editors for their important contributions in improving the quality and the readability of the manuscript.

References

  1. Allen DM, Macie DC, Wie M (2004) Groundwater and climate change: a sensitivity analysis for the Grand Forks aquifer southern British Columbia, Canada. Hydrogeol J 12(3):270–290CrossRefGoogle Scholar
  2. Angelini P, Dragoni W (1997) The problem of modelling limestone springs: the case of Bagnara (North Apennines, Italy). Ground Water 35(4):612–618CrossRefGoogle Scholar
  3. Arnell NW (1998) Climate change and water resources in Britain. Clim Change 39:83–110CrossRefGoogle Scholar
  4. Bandis SC, Lumsden AC, Barton NR (1983) Fundamentals of rock joint deformation. Int J Rock Mech Min Sci Geom Abstr 20:249–268CrossRefGoogle Scholar
  5. Bear J (1972) Dynamics of fluids in porous media. Elsevier, New YorkGoogle Scholar
  6. Bear J, Berkowitz B (1987) Groundwater flow and pollution in fractured rock aquifers. In: Nowak P (ed) Development in hydraulic engineering, vol 4. Elsevier, New YorkGoogle Scholar
  7. Bini A, Forcella F, Jadoul F, Orombelli G (eds) (2000) Carta Geologica della Provincia di Bergamo alla scala di 1:50000. Geological map of the Bergamo District at the scale 1:50000Google Scholar
  8. Birk S, Liedl R, Sauter M (2004) Identification of localised recharge and conduit flow by combined analysis of hydraulic and physico-chemical spring responses (Urenbrunnen, SW-Germany). J Hydrol 286:179–193CrossRefGoogle Scholar
  9. Brouyère S, Carabin G, Dassargues A (2004) Climate change impacts on groundwater resources: modelled deficits in a chalky aquifer, Geer basin, Belgium. Hydrogeol J 12:123–134CrossRefGoogle Scholar
  10. Cambi C, Dragoni W (2000) Groundwater yield, climatic changes and recharge variability: considerations out of the modelling of a spring in the Umbria-Marche Apennines. Hydrogéologie 4:11–25Google Scholar
  11. Chardon M (1975) Les Prealpes Lombardes et leurs bordures. «Geological setting of the Lombardy Prealps». These Univo Aix-Marseille, 655 pagg., 140 figg., 10 tavv., 3 carte f.t.Google Scholar
  12. Chen Z, Grasby SE, Osadetz KG (2004) Relation between climate change variability and groundwater levels in the upper carbonate aquifer, southern Manitoba, Canada. J Hydrol 290:43–62CrossRefGoogle Scholar
  13. Civita M (2005) Idrogeologia applicata e ambientale, “applied and environmental hydrogeology”. Casa Editrice Ambrosiana, MilanGoogle Scholar
  14. Croci A, Francani V, Gattinoni P (2003) Studio idrogeologico del bacino del Torrente Esino. Hydrogeological study of the Esino River basin. Quaderni di Geologia Applicata 10(2):148–166Google Scholar
  15. Drogue G, Pfister L, Leviandier T, Idrissi A, Iffy JF, Matgen P, Humbert J, Hoffmann L (2004) Simulation of the spatio-temporal variability of streamflow response to climate change scenarios in a mesoscale basin. J Hydrol 293:255–269CrossRefGoogle Scholar
  16. Fiorillo F, Esposito L, Guadagno FM (2007) Analysis and forecast of water resources in an ultra-centenarian spring discharge series from Serino (southern Italy). J Hydrol 336:125–138CrossRefGoogle Scholar
  17. Forkasiewicz J, Paloc H (1967) Le regime de tarissement de la Foux-de-la-Vis. Etude préliminaire. First study on the depletion curve of the Foux-de-la-Vis Spring. Chronique d’Hydrogéologie, BRGM 3(10):61–73Google Scholar
  18. Gangi AF (1978) Variation of whole and fractured porous rock permeability with confining pressures. Int J Rock Mech Min Sci Geomech Abstr 15Google Scholar
  19. Gattinoni P, Scesi L (2007) La circolazione idrica negli ammassi rocciosi. Water flow in rock masses. Casa Editrice Ambrosiana, p 156Google Scholar
  20. Harbaugh AW, Banta ER, Hill MC, McDonald MG (2000) MODFLOW-2000, the U.S. Geological Survey modular ground-water model – User guide to modularization concepts and the Ground-Water Flow Process: U.S. Geological Survey Open-File Report 00-92, 121 ppGoogle Scholar
  21. Hobbs SL, Smart PL (1986) Characterisation of carbonate aquifers: a conceptual base. Proc. 9th Int. Congr. of Speleology, BarcelonaGoogle Scholar
  22. IPCC (1997) In: Watson RT, Zinyowera MC, Moss RH, Dokken DJ (eds) The regional impact of climate change: an assessment of vulnerability: a special report of IPCC working group II. http://www.grida.no/climate/ipcc/regional/index.htm, July 2008
  23. IPCC (2000) In: Nakicenovic N, Swart R (eds) Special Report Emissions Scenarios. Cambridge University Press, UK, p 570Google Scholar
  24. IPCC (2007a) Climate change 2007: synthesis report. IPCC Plenary XXVII (Valencia, Spain, 12–17 November 2007)Google Scholar
  25. IPCC (2007b) Regional climate projections. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller HL (eds) Climate change 2007: the physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, CambridgeGoogle Scholar
  26. IPCC (2008) Climate change and water. IPCC Technical Paper VI, Geneva, 210 ppGoogle Scholar
  27. Jadoul F, Pozzi R, Pestrin S (1985) La sorgente Nossana: inquadramento geologico e idrologico. Riv Mus Sci Nat BG 9:129–140Google Scholar
  28. Kiraly L (2003) Karstification and groundwater flow. Speleogenesis and evolution of karst aquifers. Virtual Sci J 1(3):3–26Google Scholar
  29. Kiraly L, Mathey B, Tripet JP (1971) Fissuration et orientation des cavités souterraines: région de la Grotte de Milandre (Jura tabulaire). Bull Soc Neuchâteloise Sci Nat 94:99–114Google Scholar
  30. Labat D, Mangin A, Ababou R (2002) Rainfall-runoff relations for karstic springs: multifractal analysis. J Hydrol 256(3–4):176–195CrossRefGoogle Scholar
  31. Louis C (1974) Introduction à l’hydraulique des roches. Bur Rech Geol Min 4(3):283–356Google Scholar
  32. Ma T, Wang Y, Guo Q (2004) Response of a carbonate aquifer to climate change in northern China: a case study at the Shentou karst springs. J Hydrol 297:274–284CrossRefGoogle Scholar
  33. Makropoulos C, Koutsoyiannis D, Stanic M, Djordjevic S, Prodanovic D, Dasic T, Prohaska S, Maksimovic C, Wheater H (2008) A multi-model approach to the simulation of large scale karst flows. J Hydrol 248:412–424CrossRefGoogle Scholar
  34. Maillet E (1906) La vidange des systèmes de réservoirs. Ann Ponts et Chaussées Mém Doc, 218Google Scholar
  35. Meenzel L, Burger G (2002) Climate change scenarios and runoff response in the Mulde catchment (southern Elbe, Germany). J Hydrol 267:53–64CrossRefGoogle Scholar
  36. Moustadraf J, Razack M, Sinan M (2008) Evaluation of the impacts of climate changes on the coastal Chaouia aquifer, Morocco, using numerical modelling. Hydrogeol J 16:1411–1426CrossRefGoogle Scholar
  37. Negi GCS, Joshi V (2004) Rainfall and spring discharge patterns in two small drainage catchments in the Western Himalayan Mountains, India. Environmentalist 24:19–28CrossRefGoogle Scholar
  38. Oraseanu I, Mather J (2000) Karst hydrogeology and origin of thermal waters in the Codru Moma Mountains, Romania. Hydrogeol J 8(4):379–389CrossRefGoogle Scholar
  39. Ozyurt NN (2008) Residence time distribution in the Kirkgoz karst springs (Antalya-Turkey) as a tool for contamination vulnerability. Environ Geol 53:1571–1583CrossRefGoogle Scholar
  40. Ozyurt NN, Bayari CS (2008) Temporal variation of chemical and isotopic signals in major discharges of an alpine karst aquifer in Turkey: implications with respect to response of karst aquifers to recharge. Hydrogeol J 16:297–309CrossRefGoogle Scholar
  41. Qian J, Zhan H, Wu Y, Li F, Wang J (2006) Fractured-karst spring-flow protections: a case study in Jinan, China. Hydrogeol J 14:1192–1205CrossRefGoogle Scholar
  42. Sauro U (1993) Human impact on the karst of the Venetian forealps, Italy. Environ Geol 21(3):115–121CrossRefGoogle Scholar
  43. Scanlon BR, Mace RE, Barret ME, Smith B (2003) Can we simulate regional groundwater flow in a karst system using equivalent porous media models? Case study, Barton Springs Edwards aquifer, USA. J Hydrol 276:137–158CrossRefGoogle Scholar
  44. Snow DT (1970) The frequency and apertures of fractured rock. Int J Rock Mech Min Sci 7Google Scholar
  45. Thornthwaite CW (1948) An approach toward a rational classification of climate. Geogr Rev 38:55–94CrossRefGoogle Scholar
  46. Walsh JB (1981) Effects of pore pressure and confining pressure on fracture permeability. Int J Rock Mech Min Sci Geomech Abstr 18:429–435CrossRefGoogle Scholar
  47. Woldeamlak ST, Batelaan O, De Smedt F (2007) Effects of climate change on the groundwater system in the Grote-Nete catchment, Belgium. Hydrogeol J 15:891–901CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Department of Environmental, Hydraulic, Infrastructures and Surveying EngineeringPolitecnico di MilanoMilanItaly

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