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is based on the Determination of the Requirement to Include Water Quality Standards-Based Limits in CDPS
<br /> Permits Based on Reasonable Potential, dated December, 2002. All reported data was below the domestic
<br /> water supply chronic standard (for dissolved uranium)of 30 mg/l, however the highest reported value, 23.4
<br /> mg/t is greater than half of the standard, and therefore, site-specific sampling and reporting for total
<br /> recoverable uranium is required.
<br /> BASIS FOR STORMWATER MONITORING
<br /> As provided by Part 1.1 of the permit, the permittee must monitor stormwater discharges from industrial activities
<br /> conducted at the facility. Parts 1.1.1 through 1.1.4 of the permit identify the types of required monitoring, one or more
<br /> of which may apply to the discharge authorized by the stormwater permit as identified in the enclosed permit
<br /> certification for the permitted facility.
<br /> • Visual Monitoring: Part 1.1.1 of the stormwater discharge permit requires that the permittee perform quarterly
<br /> visual monitoring on stormwater-only discharges from the industrial activities conducted at the facility.
<br /> • Site specific parameters: Segment 01 c of the Lower Arkansas Sub-basin, Arkansas Basin is listed as impaired
<br /> (Regulation No. 93)for dissolved selenium, total recoverable uranium, and dissolved manganese in accordance
<br /> with Section 303(d)of the federal Clean Water Act. The Division has not yet developed a TMDL for dissolved
<br /> selenium, total recoverable uranium, and dissolved manganese for this segment. These parameters have the
<br /> potential to be in discharges from the West Farm Pit facility based on a qualitative reasonable potential
<br /> determination that sand and gravel and other earth materials at the facility are potential sources of selenium,
<br /> manganese, and uranium. Therefore, site-specific water quality based effluent sampling and reporting for
<br /> dissolved selenium, total recoverable uranium, and dissolved manganese is required.
<br /> FEE INFORMATION (V-A 270)
<br /> The Annual Fee for this certification is$270 (category 07, Subcategory V-A-Sand and gravel with process discharge and
<br /> stormwater, per CRS 25-8-502). Do Not Pay This Now. Annual fees are sent to the legal or billing contact in July.
<br /> GENERAL INFORMATION
<br /> • Changes to the certification: Any changes that need to be made to the certification page-changes in sampling
<br /> location, monitoring requirements, etc., must be submitted using the "Permit and Certification Modification
<br /> form"available on the Division's website, www.coloradowaterpermits.eom, and signed by the legal contact.
<br /> • Flow Monitoring Frequency: The application did not specify whether the permittee uses 'continuous' or
<br /> 'instantaneous' flow measurement. If power is not available, flow may be measured on an instantaneous basis.
<br /> If this is the condition at the facility, the permittee may submit a modification request to the division to change
<br /> the flow measurement technique to 'instantaneous'.
<br /> • Monitoring and requirements: Monitoring must occur at the frequency established in the permit certification.
<br /> Weather conditions may not always allow the permittee to collect a sample during business hours; however, the
<br /> monitoring frequency established in the permit certification must be met. For facilities required to conduct
<br /> chemical monitoring, the Division strongly recommends that the permittee contact a tab prior to setting up a
<br /> sampling program.
<br /> Process water sampling shall occur at a point after treatment, or after the implementation of any control
<br /> measures. If control measures or treatment are not implemented, sampling shall occur where the discharge
<br /> leaves control of the permittee, and prior to entering the receiving stream. Samples must be representative of
<br /> what is entering the receiving stream.
<br /> Stormwater monitoring location(s), i.e., outfalls, are locations where stormwater exits the facility property,
<br /> including pipes, ditches, swates, sheet flow and other structures that transport stormwater. The permittee
<br /> must modify the facility SWMP to include a description of all stormwater outfalls. Stormwater outfalls must be
<br /> representative of the facility's stormwater discharge. A facility may require more than one stormwater outfall
<br /> where pollutant sources vary across the facility.
<br /> • Discharge Monitoring Reports (DMRs): DMRs will be mailed or emaited approximately one month following
<br /> certification issuance. DMRs must be submitted quarterly as long as the certification is in effect. If the
<br /> permittee, using an approved analytical method, monitors any parameter more frequently than required by this
<br /> Fact sheet Page 3 of 5
<br /> 4300 Cherry Creek Drive S ,Denver,CO 80246-1530 P 303-692-2000 www.coLorado.gov/cdphe/wgcd
<br /> John W. Hickentooper,Governor I Larry Wolk,MD,MSPH,Executive Director and Chief Medical Officer
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