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8. Cotter is responsible for the increased uranium in Ralston Creek through the <br />alluvial fill and mine pool. <br />9. The mine pool is contributing to the contamination of Ralston Creek and the <br />Reservoir. The mine pool is affecting the hydrologic balance of the affected land and <br />surrounding area. The mine pool could significantly negatively impact water quality <br />in Ralston Creek and the Reservoir. <br />10. Dewatering the mine pool to a level below the level of Ralston Creek will ensure <br />that the hydraulic gradient is again reversed away from Ralston Creek and the <br />Reservoir. <br />11. Protecting the water in Ralston Creek and the Reservoir is essential. <br />12. Dewatering the mine pool will be expensive. However, the benefit (protecting <br />Denver and Arvada's drinking water supply) justifies the expense. <br />The Board made the following conclusion of law, among others: <br />1. The Board considered the potential expense of dewatering the mine against the <br />threat to human health and safety posed from contaminated water migrating to <br />Ralston Creek and the Reservoir. The Board concluded that the benefits expected to <br />result from. dewatering the mine outweigh Cotter's potential costs of carrying out the <br />dewatering. <br />2. Cotter failed to minimize disturbances to the prevailing hydrologic balance in <br />Ralston Creek and the mine pool. The mine pool has contributed uranium to Ralston <br />Creek. Cotter greatly disturbed the quality of water in surface and ground water <br />systems. <br />3. The uranium level in the mine pool is a serious adverse impact to the prevailing <br />hydrologic balance. <br />4. Uranium in Ralston Creek resulted from Cotter's failure to protect the drainage <br />system from uranium. The mine pool poses a serious threat to downgradient water <br />resources. The site's drainage system is negatively impacted by Cotter's failure to <br />handle toxic-forming material (uranium) in a protective manner. <br />5. Cotter contaminated the alluvial fill and mine pool with uranium and other metals. <br />The contaminated alluvial fill and mine pool water significantly increased levels of <br />uranium in Ralston Creek. Ralston Creek's significantly increased uranium <br />concentrations are outside of the site's affected area. Cotter failed to protect areas <br />outside of the affected area from damage during the mining operation and <br />reclamation.