Dégradation progressive du milieu par le surpâturage et le déboisement et conséquences hydrologiques. Étude de cas dans la Sierra Madré occidentale (Mexique)
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Medientyp:
E-Artikel
Titel:
Dégradation progressive du milieu par le surpâturage et le déboisement et conséquences hydrologiques. Étude de cas dans la Sierra Madré occidentale (Mexique)
Beteiligte:
Viramontes, David;
Descroix, Luc
Erschienen:
PERSEE Program, 2000
Erschienen in:Revue de géographie alpine
Sprache:
Französisch
DOI:
10.3406/rga.2000.2989
ISSN:
0035-1121
Entstehung:
Anmerkungen:
Beschreibung:
<jats:p>Abstract : The western Sierra Madré represents a « water tank » for surrrounding plains and plateaux that have an arid or semi arid climate ; these regions have used during more than fifty years overland flow to practice irrigation in great areas (for example the Laguna with 160 000 ha has more than 12 million inhabitants). However, in the mountain, ove- rexploitation of natural resources by breeding and forestry results in an environment degradation. A decomposition of hydrograms has been attempted to put in light eventual changes in water balance. Using an algorithm which allows to separate base flow and flood flow, an interpretation of hydrological trend of hydrologie behaviour of the basins. The annual runoff does not change ; but the way runoff occurs has changed. Discharges are торге irregular in the last decades ; the proportion of base flow in annual discharge decreases and inversely, flood flow enhances. This is what appears as the consequences of the landscape degradation : overgrazing and deforestation have accelarated runoff. The hydrological evolution leads environmental and economical consequences to downstrean arid zones, which absolutely need the water of the western Sierra Madre.</jats:p>