Major construction projects, especially new office, residential and mixed-use buildings, often require dewatering to remove intercepted groundwater from subterranean areas. Intercepted water flows may continue even after construction is completed. When CDOT encountered high levels of arsenic in the groundwater during highway construction near Santa Fe and Broadway, it was precluded from disposing of the water by releasing it back into the stream. Consequently, CDOT trucked 200 million gallons of water to another location at a cost of $1.6 million during the course of the project. Throughout the Denver metro area, developers continue to encounter elevated background levels of arsenic, selenium, other metals and nutrients—the types and amounts of such contaminants vary by location. Similar groundwater conditions are encountered in other areas of the state.