National parks are different from other federal lands in the United States. Beginning in 1872 with the establishment of Yellowstone, they were largely set aside

Richtlijnen voor de werker in het veld om problemen te ondervangen ten aanzien van de waterkwaliteit voor irrigatie-doeleinden. Tenslotte worden praktijkervarin

The southwestern deserts stretch from southeastern California to west Texas and then south to central Mexico. The landscape of this region is known as basin and