Total Maximum Daily Load (TMDL) is used to determine the maximum amount of a pollutant that a water body may receive and still maintain water quality standards. The mainstem of Silver Creek from a point immediately below the Town of Ricos water supply diversion to the confluence with the Dolores River is included in the 2006 303(d) list for exceeding the Aquatic Life use standards for zinc and cadmium.
This Corrective Measures Work Plan (CMWP) evaluates and selects appropriate corrective measures for the remediation of environmental contamination at the Hamilton Sundstrand Former Denver Facility. ARCADIS U.S., Inc. (ARCADIS) is responsible for the design, implementation, and operation of the remediation systems at the site under a Guaranteed Remediation Program Agreement. In addition to evaluating and selecting corrective measures, this CMWP also broadly summarizes site information and the results of activities identified in the ICAP Application including the implementation of interim corrective measures and pilot-scale tests of remedial technologies.
The Colorado Department of Public Health and the Environment (CDPHE) has identified Sanchez Reservoir in Costilla County as not supporting its designated uses due to the presence of elevated fish tissue concentrations of mercury that have resulted in Fish Consumption Advisories. Mercury concentrations at the levels observed present a significant health risk to persons who consume listed fish from the reservoir. Because Sanchez Reservoir does not support its designated uses, a Total Maximum Daily Load (TMDL) is required for mercury loading to the lake.
The Kerber Creek watershed is tributary to San Luis Creek and part of the Rio Grande Closed Basin. The mainstem of Kerber Creek from its source to the confluence with San Luis Creek first appeared on the Colorado 1998 303(d) list for non-attainment of cadmium (total recoverable) and silver (total recoverable) standards for Segment 9a, and for non-attainment of dissolved cadmium, dissolved copper, and dissolved zinc in Segment 9b. Segment 9a was also listed for pH and lead (total recoverable) in 2006.
The Colorado Cooperative Program for Environmental Health Assessments (CCPEHA) was initially contacted in July of 2007 to assist with community concerns regarding consumption of fruits and vegetables from domestic gardens irrigated with contaminated groundwater. After a preliminary investigation of the available environmental data, including sample data generated from residents' fruits and vegetables, it was decided that a health consultation should be conducted to address the potential public health hazards associated with exposure to groundwater contaminants. This health consultation focuses on residential exposures to groundwater contaminants in the Fairmont neighborhood.
This guidance document is intended to inform the Division regarding the selection of analytical methods and associated practical quantitation limits (PQLs) for use in permits issued for discharges to surface waters or ground water under the Colorado Discharge Permit System (Regulation No. 61).
