Assessment of the conservation status of the watersheds of Nuevo León, Mexico

Abstract

In order to evaluate the conservation status of the watersheds of Nuevo León, 48 environmental variables were analyzed to construct four indexes. Four of the fourteen watersheds in Nuevo León cover 79 % of the state territory. Most prominent among them is the Río Bravo–San Juan basin, which houses within it Monterrey’s Metropolitan Area, where over 90 % of the inhabitants of the state dwell. In contrast, six basins of Nuevo León cover a total of 2 492 km² (3.9 % of state territory), and therefore they can be considered marginal. The six marginal watersheds of Nuevo León, in addition to Río Soto La Marina, obtained the lowest scores for the Index of Sites with Official Declaration (< 2.4 points). The three basins with the highest scores for the Index of Proposed Priority Sites are among the marginal basins: Sierra de Rodríguez, Río Tamesí and Matehuala, with values of 45.3, 39.1, and 36.8 points, respectively. The Río Bravo- San Juan and Río San Fernando basins registered the highest values for the Environmental Impact Index, with 60.7 and 40.5 points, respectively. For the Conservation Status Index, five of the 14 basins showed positive values (Río Tamesí, Sierra Madre Oriental, Matehuala, Sierra de Rodríguez and Presa San José-Los Pilares), four of which are marginal, covering a joint surface area that amounts to only 2.3 % of the state. The fifth with positive value for this index was the Sierra Madre Oriental basin, while the nine remaining basins (Río Bravo–Matamoros-Reynosa, Río Bravo–San Juan, Río Bravo–Sosa, Presa Falcón-Río Salado, Río Bravo-Nuevo Laredo, Río Soto La Marina, Laguna Madre, Río San Fernando and Sierra Madre Oriental) obtained negative values for this index, which means that the environmental impacts exceed the conservation attributes of these watersheds.