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<br />It —COLORADO
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<br />Department of Public Water Quality Assessment
<br />6' Health b Environment
<br />As shown in Table A -11f, there are no new or increased impacts to the receiving stream based on the new
<br />WQBELS for total recoverable iron. The AD evaluation for this parameter is complete, and the WQBELs are
<br />the final result of this WQA.
<br />For those parameters where there is not a NIL (either implicit or explicit) the AD Guidance allows for the
<br />collection of data to determine an implicit limitation. Therefore, the permittee will be required to conduct
<br />"monitoring only" for those parameters.
<br />New Outfall 025
<br />As outfall 025 this is a new outfall, there are no NILS and implicit limitations do not apply.
<br />Because outfall 025 was not in existence as a discharger to Deacon Gulch and the Yampa River as of
<br />September 30, 2000, the influence of this discharger is not considered when determining the BWQ. Further,
<br />since this section of the Yampa River is a habitat for a threatened and endangered species, no dilution is
<br />available, and the flow is set at zero for aquatic life pollutants. Data collected at WQCD 12804 (Yampa River
<br />at Hwy 394 South of Craig) located directly upstream from the point Deep Cut Ditch enters the Yampa River
<br />were used. Data are available for dissolved and total recoverable arsenic, dissolved cadmium, dissolved
<br />copper, dissolved lead, dissolved lead and dissolved zinc from 3/31/1999. As only one sample was available
<br />for the AD period, additional data collected more recently was used. Data from WQCD 12804C (Yampa River
<br />at Dorsey SWA Boat Launch) located approximately 12 miles upstream of the location the Deep Cut Ditch
<br />discharges into the Yampa River were available for a period of record of July 2011 through May 2012 for
<br />dissolved arsenic, dissolved cadmium, dissolved chromium, dissolved copper, dissolved lead, dissolved nickel,
<br />dissolved selenium, dissolved silver and dissolved zinc. Data from USGS 09244490 (Yampa River above Elkhead
<br />Creek near Hayden, CO) located approximately 12 upstream of the point Deep Cut Ditch enters the Yampa
<br />River were available for a period of record from April 2010 through November 2014 for dissolved cadmium,
<br />dissolved copper, dissolved lead, dissolved silver, dissolved selenium and dissolved zinc. These data were
<br />used to determine BWQ for outfall 025.
<br />Data at WQCD 12804C and USGS 09244490 were not collected during the five years prior to September 2000.
<br />The Division has determined that, absent sufficient data available during the AD period, the available data
<br />are considered representative of ambient water quality during the AD review period.
<br />The ambient water quality data are summarized in Table A-12. The BWQ concentrations based on these
<br />data, represented by the 50th percentile for total recoverable metals and the 85th percentile for dissolved
<br />metals, and other pollutants, are summarized in Table A-13.
<br />Paine 33 of 40
<br />4300 Cherry Creek Drive S., Denver, CO 80246-1530 303-692-2000 www.cotorado.gov/cdphe/wqcd I ��
<br />Table A -1 1f
<br />Determination of New or Increased Impacts at Outfall 023 Discharge to the Yampa River
<br />Sept
<br />Sept
<br />2000
<br />20002000
<br />New
<br />New or
<br />Permit
<br />Permit
<br />NIL
<br />New
<br />WQBEL
<br />Increased
<br />Limit/
<br />Load
<br />WQBEL
<br />Load
<br />Impact
<br />Implicit
<br />(lbs/day)
<br />(lbs/day)
<br />NIL
<br />Aquatic Life Parameters
<br />Fe, TR pg/() 3000
<br />23 1 3000
<br />1000 18
<br />No
<br />As shown in Table A -11f, there are no new or increased impacts to the receiving stream based on the new
<br />WQBELS for total recoverable iron. The AD evaluation for this parameter is complete, and the WQBELs are
<br />the final result of this WQA.
<br />For those parameters where there is not a NIL (either implicit or explicit) the AD Guidance allows for the
<br />collection of data to determine an implicit limitation. Therefore, the permittee will be required to conduct
<br />"monitoring only" for those parameters.
<br />New Outfall 025
<br />As outfall 025 this is a new outfall, there are no NILS and implicit limitations do not apply.
<br />Because outfall 025 was not in existence as a discharger to Deacon Gulch and the Yampa River as of
<br />September 30, 2000, the influence of this discharger is not considered when determining the BWQ. Further,
<br />since this section of the Yampa River is a habitat for a threatened and endangered species, no dilution is
<br />available, and the flow is set at zero for aquatic life pollutants. Data collected at WQCD 12804 (Yampa River
<br />at Hwy 394 South of Craig) located directly upstream from the point Deep Cut Ditch enters the Yampa River
<br />were used. Data are available for dissolved and total recoverable arsenic, dissolved cadmium, dissolved
<br />copper, dissolved lead, dissolved lead and dissolved zinc from 3/31/1999. As only one sample was available
<br />for the AD period, additional data collected more recently was used. Data from WQCD 12804C (Yampa River
<br />at Dorsey SWA Boat Launch) located approximately 12 miles upstream of the location the Deep Cut Ditch
<br />discharges into the Yampa River were available for a period of record of July 2011 through May 2012 for
<br />dissolved arsenic, dissolved cadmium, dissolved chromium, dissolved copper, dissolved lead, dissolved nickel,
<br />dissolved selenium, dissolved silver and dissolved zinc. Data from USGS 09244490 (Yampa River above Elkhead
<br />Creek near Hayden, CO) located approximately 12 upstream of the point Deep Cut Ditch enters the Yampa
<br />River were available for a period of record from April 2010 through November 2014 for dissolved cadmium,
<br />dissolved copper, dissolved lead, dissolved silver, dissolved selenium and dissolved zinc. These data were
<br />used to determine BWQ for outfall 025.
<br />Data at WQCD 12804C and USGS 09244490 were not collected during the five years prior to September 2000.
<br />The Division has determined that, absent sufficient data available during the AD period, the available data
<br />are considered representative of ambient water quality during the AD review period.
<br />The ambient water quality data are summarized in Table A-12. The BWQ concentrations based on these
<br />data, represented by the 50th percentile for total recoverable metals and the 85th percentile for dissolved
<br />metals, and other pollutants, are summarized in Table A-13.
<br />Paine 33 of 40
<br />4300 Cherry Creek Drive S., Denver, CO 80246-1530 303-692-2000 www.cotorado.gov/cdphe/wqcd I ��
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