The relationship between toxins and wetlands is a contains incongruities. Wetlands act to filter toxins, yet too many toxins can be detrimental to a wetland. We must conserve wetlands because of their ability to buffer toxins, yet in order to preserve wetlands we must reduce toxins. The San Luis valley has a unique geology and topography which results in an extraordinary hydrology of the area. The valley is bound by the Sangre de Cristo Mountains on the east and the San Juan Mountains on the west.
Cross faults divide the basin into two sections.
The northern section of the basin is a closed basin as a result of this cross faulting. The aquifer system is a thick and multilayered system. As a consequence, discharge of ground water through evapotranspiration is extremely high in these areas of the valley. The irrigation in the valley remained confined to surface water for limited farming for 250 years. America acquired the San Luis Valley after the Mexican War ended in 1848.