Although the government has been far more successful in its efforts to clean up the water and soil than the air, the use of additional or alternative policies may also be advantageous.  A command and control policy that allows only a set amount of effluents into the water system may provide a more efficient level of control.  This could be accomplished through federal mandates that all the companies working on government land, or on government contracts, use low emissions and low effluents vehicles and equipment.  This would account for a part of the water and soil problem, but a large piece of the pollution is generated from the construction into the existing rock.   Although there is no way to alter the acidic rock from its natural state, a cap on the amount of construction would help.  Many people already advocate that there should be no construction or logging in the national parks.  However, a panel of environmentalists, economists, and government agents could surely find an acceptable, sustainable, and efficient amount of construction.  Such a cap is easily understandable in light of the park's intended use as a sanctuary for the wildlife and plants within its borders.