Blanc SIMI 6 - Sciences de l'information, de la matière et de l'ingénierie : Système Terre, environnement, risques

A trans-disciplinary approach to quantify water resources and their impact on natural ecosystems in the Galapagos Islands – GIIWS

GIIWS

A trans-disciplinary approach to quantify water resources and their impact on natural ecosystems in the Galápagos Islands

ydrodynamic functioning of volcanic islands & ecosystem conservation

The objectives of this project are: (I) To improve the understanding of hydrogeology in tropical volcanic islands of intra-plate origin. (II) To show the invaluable input of jointed investigations in hydrological and ecological sciences for the understanding of ecosystem functioning and restoration of ecosystems in fragile areas. (III) To address local challenges of conservation, protection of native and endemic ecosystem

The scientific programme will consist in (i) a quantification of recharge rates (ii) a analysis with an hydrogeological approach of the morphology, geometry and physical properties of volcanic formations, including the exploitation of all direct and indirect methods to characterize groundwater occurrence, and (iii) assess the consistency of the whole and potential consequences with numerical groundwater flow modelling.

Expected innovating scientific advances include: i) new understanding of groundwater flow in complex fractured volcanic formations where freshwater and salt water interact, ii) groundwater model based validation of 3-D geophysical exploration, iii) strong collaboration between biological sciences and natural sciences.

Through our results, we will guarantee that sustainable water management is incorporated into the urban planning in order to reduce contamination to the environment and improve basic sanitary conditions of the human population. Furthermore, restoration ecology is becoming a flagship of conservation projects, and our research will provide the necessary input to link natural sciences such as hydrology and soil physics with ecology.

7 scientific paper, 27 communications/poster, 12 reports of student (L, M PhD), 7 activity report, 9 scientific dissemination documents including a scientific movie

Renown worldwide as a sanctuary of pristine ecosystems and endemic species which inspired Charles Darwin in this theory on evolution, the Galapagos Islands are today undergoing rapid change, potentially threatening the integrity of this unique place. Demographic growth in the islands has increased exponentially, in parallel to the expanding tourism industry, since the 1980s. Sustainable management of natural resources, such as freshwater, a rare element in these islands, is critical to ensuring protection of natural systems and a healthy and controlled development of human settlements. Until the present day, lack of knowledge regarding freshwater, for example, was an impeding factor to integrated freshwater management. Although contamination problems were known around the human settlements, no management actions were taken. This is why the Galapagos Islands: Integrated Water Studies (GIIWS) program was started seven years ago: to understand the hydrological functioning of the islands and provide information to allow the local institutions to carry out management in view of maintaining the integrity of the ecosystems and reduce mis-management of the resource.

The results from the first phase of the program revealed a dynamic freshwater system with little or no manifestation on the surface on Santa Cruz Island, but a complex system of surface drainage on San Cristobal Island. Shallow basal aquifers were observed on both islands from geophysical investigations. On Santa Cruz Island, this aquifer is the main water source for the local towns. It is a brackish water influenced by tidal signal up to 5 km inland. The complex network of perched aquifers on San Cristobal which feed into the small river system is replaced on Santa Cruz by an apparently buried, continuous perched aquifer layer with no outcrop. Interesting preliminary results were obtained regarding the contribution of light mist/rain during the cool season to the whole hydrological regime, whereas previously it was thought that only during the rainy season would recharge to the natural system be of importance. This interesting result was later confirmed by contribution from fellow botanists working on the ecology of an invasive plant. Novel results from this research were published internationally as contributions to the field of remote sensing, geophysics and volcanic island hydrogeology.

Given the support and enthusiasm of the Galapagos National Park and the Charles Darwin Foundation (the local research institute) for our work, a second phase of the project was prepared. The objective of this phase is to build upon the existing results and quantify the distinct components of the water cycle on the Island of Santa Cruz. Accessibility of this island, existing projects in ecological restoration, and the urban/rural water resource management problems led us to focus our work here. Also a very important component of this second phase is the working collaboration with scientists from the field of biology, and in particular botany, in a form to give this project a truly trans-disciplinary nature. To deepen our understanding of certain hydrological processes in these unique ecosystems and how these would be impacted by changes in the hydrology required their complete input and participation in the project. Given the strong team which has been committed to working in the Galapagos Islands, for their conservation and for a sustainable form of development, a numerical modelling of the hydrological functioning will be developed at the end of this phase of the project.

A scientific challenge with high environmental stakes, still very little is known on the hydrology of these protected Islands. As we reach out to work with the biological scientists, we hope also to set the bases for a new field of science in Galapagos, hydro-ecology, with promising applications, and especially in the view of future climate change.

Project coordinator

Madame Sophie VIOLETTE (UNIVERSITE PIERRE ET MARIE CURIE (Paris 6)) – sophie.violette@upmc.fr

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

CNRS CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - Délégation Paris B
Armines ASSOCIATION POUR LA RECHERCHE ET LE DEVELOPPEMENT DES METHODES ET PROCESSUS INDUSTRIELS (ARMINES)
CEMAGREF/IRSTEA CENTRE NATIONAL DU MACHINISME AGRICOLE, DU GENIE RURAL, DES EAUX ET DES FORETS - CEMAGREF
UPMC UNIVERSITE PIERRE ET MARIE CURIE (Paris 6)

Help of the ANR 440,000 euros
Beginning and duration of the scientific project: - 36 Months

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