Post-Gold King 

Mine Release 

Incident: 

Conceptual 

Monitoring Plan 

for Surface 

Water, 

Sediments, and 

Biology 

EPA Draft 

September 2015 
DRAFT 

Post-Gold King Mine Release Incident Conceptual Monitoring Plan 

For Surface Water, Sediments and Biology 

 

I. Background – Gold King Mine Release Incident and Animas River 

Watershed Historic Conditions 

On August 5, 2015, EPA was conducting an investigation of the Gold King Mine (GKM) near Silverton, 

Colorado to assess the on-going water releases from the mine, treat mine water, and assess the 

feasibility of further mine remediation. While excavating above an old adit, pressurized water began 

leaking above the mine tunnel, spilling about three million gallons of water stored behind the collapsed 

material into Cement Creek, a tributary of the Animas River (http://www2.epa.gov/goldkingmine). The 

Animas River originates in the mountain peaks northeast of Silverton, in San Juan County, Colorado. It 

ends in Farmington, New Mexico, where it empties into the San Juan River terminating in Lake Powell in 

Utah. The conceptual monitoring strategy outlined in this document is designed to collect data in these 

surface waterbodies potentially impacted by the GKM Release Incident. Because this watershed has 

been historically impacted by mining releases and natural mineralization and these releases continue 

today, difficulties exist in identifying and distinguishing potential impacts of the GKM Release Incident 

from the many other ongoing sources of impacts described in this section. 

The upper reaches of the Animas watershed are heavily impacted by historic mining activities and 

natural mineralization. Many abandoned mines exist within a two-mile radius in the headwaters 

including: the Upper Gold King, American Tunnel, Grand Mogul, Mogul, Red and Bonita, Eveline, 

Henrietta, Joe and John, and Lark mines. Some of these mines have acid mine drainages that produce 

flows of between 30 and 300 gallons per minute that directly or indirectly enter Cement Creek and 

eventually reach the Animas River. These flows were occurring prior to the GKM Release Incident and 

are ongoing. As a result, numerous remediation activities have been initiated in the watershed. The 

Animas River Stakeholder Group, the Bureau of Land Management, the Colorado Division of 

Reclamation/Mining and Safety, and EPA Region 8 have completed remediation projects in the 

watershed (EPA Region 8, Upper Animas Mining District: Draft Baseline Ecological Risk Assessment,

http://www2.epa.gov/region8/upper-animas-mining-district-draft-baseline-ecological-risk-assessment). 

The Colorado Department of Public Health and the Environment has developed more than twenty-five 

Total Maximum Daily Loads (restoration plans required for waterbody segments considered impaired 

under the Clean Water Act) to help guide restoration activities towards meeting water quality standards. 

However, for some waters, including Cement Creek, the State has followed procedures under the Clean 

Water Act to remove aquatic life support as a designated use for the waterbody because it is not an 

attainable goal (Colorado Department of Public Health & Environment, 

https://www.colorado.gov/pacific/cdphe/tmdl-san-juan-and-dolores-river-basins). 

Though restoration activities and plans have been underway in the watershed, aquatic life uses in 

numerous segments of the watershed remain impaired by heavy metals (Colorado Department of Public 

Health & Environment, https://www.colorado.gov/pacific/sites/default/files/Regulation-93.pdf). 

The Animas River Stakeholders Group (ARSG), which updated a watershed plan for remediating 

historical mining sites in the Upper Animas River Basin in 2013, estimates that in recent years untreated 

acid mine drainage from Cement Creek alone has been in the range of 600-800 gallons per minute or 

about 314-420 million gallons per year, with increases in metals loadings observed 40 miles downstream 

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DRAFT 

Post-Gold King Mine Release Incident Conceptual Monitoring Plan 

For Surface Water, Sediments and Biology 

in the Animas River 

(http://ofmpub.epa.gov/apex/grts/f?p=110:700:13401198170892::NO:RP,700:P700_PRJ_SEQ:62860). 

This document describes post-release surface water quality, sediment quality, and biological community 

monitoring that will occur over the course of the year following the GKM Release Incident. Data 

collected over the next year will support an assessment of the changes in surface water and sediment 

quality since the GKM Release Incident across the full range of seasonal flow conditions. While this plan 

focuses on surface water and sediment quality, EPA is exploring a sampling regime for private drinking 

water wells. As part of its response to the GKM Release Incident, EPA has collected and tested more 

than 650 samples from private drinking water wells. The EPA is following up on 3 wells with exceedances 

of maximum contaminant limits (MCLs) for drinking water to determine if there is any connection to the 

GKM release. Currently, sampling of drinking water wells is not included in this plan. Recognizing 

continued interest, EPA is taking comment and input on whether further action is needed on private 

wells. The EPA would like stakeholder input on the frequency, duration, location and scientific basis for 

continuing sampling of private wells.

II. Context for Conceptual Monitoring Plan and Data Uses 

This is a conceptual monitoring plan in that it outlines the objectives, boundaries, and guiding principles 

for this effort. This allows for stakeholder review and input prior to finalization of more detailed 

documents. It is not intended to replace a Quality Assurance Project Plan (QAPP) or Sampling and 

Analysis Plan; but rather, serves to direct the development of such. 

The monitoring effort described in this document will gather comprehensive data that span the 

watershed potentially affected by the GKM Release Incident. These data may be useful for a variety of 

purposes for the EPA, States, Tribes, and stakeholders and serve to increase our understanding and 

characterization of conditions across the watershed. A variety of media will be sampled and the 

objectives of this study are described in Section III. This monitoring and associated assessment will not 

constitute characterization for the Clean Water Act (CWA) Section 303(d) and 305(b) assessment 

determinations or site assessment/remedial investigation purposes under the Comprehensive 

Environmental Response, Compensation and Liability Act (CERCLA); however, these data may support 

such efforts. The EPA may use a variety of regulatory and response authorities to conduct studies, 

initiate cleanup actions, facilitate public participation, and otherwise contribute to the cleanup of 

watersheds contaminated with hazardous substances and wastes. The EPA has developed guidance for 

federal and state program managers on integrating waste and water program to restore watersheds, 

which can be found here: http://www.epa.gov/superfund/resources/pdfs/cross-program.pdf

This monitoring study is designed to collect data in the surface waterbodies potentially impacted by the 

GKM Release Incident to determine if water and sediment quality trends are similar to trends observed 

before the GKM release. While the latest monitoring information after the GKM Release Incident shows 

contaminant levels have returned to pre-spill levels, this study’s monitoring information will serve to 

inform if these findings remain consistent across the range of annual flow conditions. 

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DRAFT 

Post-Gold King Mine Release Incident Conceptual Monitoring Plan 

For Surface Water, Sediments and Biology 

It is important to recognize that the information collected for this monitoring study may not be 

sufficient to attribute elevated contaminant levels or possible biological metrics to the August 5, 2015, 

GKM release. The limits of this study’s data to provide release-specific attribution follow from the many 

years of historic mine drainage releases from the GKM, the ongoing acid mine drainage releases from 

other mines into the Animas River (and downstream water bodies) and the limited availability of prerelease water quality conditions. 

Monitoring and assessment efforts occurring prior to the GKM Release Incident identified pre-existing 

impairments to water quality, sediment quality, and biological communities in this watershed. 

Numerous sources of metals contamination are present that have impacted environmental quality 

before the GKM Release Incident and continue to impact environmental quality post GKM Release 

Incident. Therefore, our ability to determine if current environmental impacts relate to the GKM Release 

Incident is confounded by the presence of these other sources, and typical conditions in many areas of 

this watershed are not pristine nor free of impairments. Any new data that are gathered can only be 

understood with respect to the GKM Release Incident by a comparison to previous conditions that 

reflect historic impairment sources. Hence, the ease of interpretation of data gathered under this 

strategy greatly depends on the amount and quality of historic data that are available for comparison. 

Sites, media, and analytes for which there are robust historic datasets for pre- and post-release 

comparison will be the most useful in understanding whether typical conditions in this watershed are 

being maintained after the GKM Release Incident. A comparison of current data to data collected under 

pre-release/historic conditions should allow for an understanding of whether there are changes in water 

quality and sediment quality trends post-GKM Release Incident over the next year or whether typical 

conditions are witnessed. Biological data are being collected as well; however, historic datasets are 

more limited and biological data are more difficult to interpret and compare. Therefore, the primary 

media to be used in determining maintenance of pre-release or historic conditions are surface water 

and sediment. 

Some sites that do not have robust datasets will be sampled because they are necessary to provide a 

more complete geographic distribution of data collection under this strategy. Data for sites, media, and 

analytes, for which there is not a historic dataset for comparison, will not be useful for determining 

changes in environmental quality as a result of the GKM Release Incident and should not be used to this 

end. However, these data are important for increasing our understanding and characterization of the 

watershed with respect to the many complex existing contaminant sources and stressors that have been 

and continue to be present. These data serve to inform stakeholders of the environmental conditions 

across the wider watershed, begin the development of a historic data set for more locations in the 

watershed, and provide valuable information for decision makers. 

After completing one year of monitoring under this plan, if results indicate a return to prerelease/historic trends, monitoring efforts under this plan will end and routine monitoring will continue 

per State, Tribal, and Federal program strategies and priorities. If pre-release/historic trends across the 

watershed are not maintained at some locations in the watershed, the EPA will conduct additional sitespecific investigations as appropriate and use its authorities to work with other federal agencies, States, 

Tribes, and local entities to address these problems. The EPA is coordinating with its regulatory partners 

and affected stakeholders to understand other organizations’ monitoring efforts, prevent duplication, 

and promote data sharing. 

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Post-Gold King Mine Release Incident Conceptual Monitoring Plan 

For Surface Water, Sediments and Biology 

III. Objectives and Study Questions 

This document outlines EPA’s proposed conceptual monitoring strategy, assessment goals and general 

methods for evaluating surface waters, sediments, and biological communities downstream of the GKM 

Release Incident. This document outlines monitoring to be undertaken by the EPA and key stakeholders 

or regulatory partners that will support collaborative assessment of the pre- and post-release 

conditions. States and Tribes may consider this a framework for additional sampling that they wish to 

undertake. 

The objectives of the monitoring strategy are limited in scope by the availability of historic or prerelease data. In this document pre-release data include results of sampling that occurred just prior to 

the GKM Release Incident. Historic data include longer term data sets that reflect many years of 

sampling and contaminant trends. Pre-release and historic data for metals in sediment, metals in water 

and biological assemblages are available for the Animas River in Colorado and Southern Ute Indian 

Reservation due to proximity of mine locations and past and continued interest in the effects of mining 

run-off. However, pre-release and historic data for both metals in sediment and water as well as 

biological information are less abundant further downstream on the Animas and San Juan River in New 

Mexico, Ute Mountain Ute Reservation, the Navajo Nation, and Utah. Due to the discrepancy of 

available pre-release and historic data and potential challenges faced by downstream states in assessing 

pre-release/historic trends with post-release conditions, two objectives for this study are proposed: 

• Objective A: Identify changes in surface water or sediment quality trends since the GKM Release 

Incident in Cement Creek, Animas River, and the San Juan River by comparing post-release data 

against pre-release or historic trends. Only data that meet the requirements of Objective A, in 

that pre-release and post-release comparisons can be made, will be used to assess the changes 

since the GKM Release Incident. 

• Objective B: Assess only current conditions of Cement Creek, Animas River, San Juan River, and 

Lake Powell where historic or pre-release data are absent or limited. Data solely collected to 

meet Objective B will not be sufficient in assessing the changes since the GKM Release Incident 

without additional information. 

Objective A: Identify changes in surface water or sediment quality trends since the GKM Release Incident 

in Cement Creek, Animas River, and the San Juan River at sites in Colorado, Southern Ute Reservation, 

New Mexico, Ute Mountain Ute Reservation, Navajo Nation, and Utah by comparing post-release data 

against pre-release or historic trends for all sampling sites possible. Only data that meet the 

requirements of Objective A, in that pre-release and post-release comparisons can be made, will be used 

to assess the changes since the GKM Release Incident. Include biological community and biological tissue 

data-set comparisons if historic datasets allow. 

The primary purpose of this objective is to identify changes since the GKM Release Incident that 

occurred on August 5, 2015 by comparing post-release data against pre-release or historic trends for 

each sampling location. The study questions identified below provide the context used in selecting 

sampling locations and analytes of interest for this objective. 

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Post-Gold King Mine Release Incident Conceptual Monitoring Plan 

For Surface Water, Sediments and Biology 

For this effort, it is necessary that data be collected at sites for which historic and/or pre-release data 

trends are available so that historic and/or pre-release trends may be compared to the data collected 

through this monitoring effort. Potential sampling locations are identified in this document with 

emphasis placed on those sites for which historic data are available. Pre-release and historic data 

availability are understood for most of these potential sites or will be compiled and analyzed prior to 

final site selection. Stakeholders may have alternative (replacement) sites of interest for those identified 

in Table 2. 

Assessment Objective A: 

Compare pre-release (or historic) and post-release surface water data, sediment data and biological 

data of Cement Creek, the Animas River, and the San Juan River. 

Study Questions – Objective A: 

1. Have water and sediment quality trends in Cement Creek, the Animas River, and the San Juan 

River changed since the GKM Release Incident? 

a. What are the water column and sediment metals concentrations/loadings and how do 

they compare to pre-release or historic trends? 

b. What are the conditions of the biological communities, macroinvertebrates and fish, 

and how do the indices used to assess them compare to pre-release or historic 

conditions? 

2. If post-release conditions are of lower quality than pre-release/historic trends, are water quality 

standards or screening levels exceeded for human health (including recreation and fish 

consumption), agricultural, and aquatic life uses in the watershed? 

If metals concentrations in sampled media are higher than pre-release/historic trends, 

are they meeting screening levels identified as acceptable for recreation, agriculture, 

and aquatic life? Screening levels that may be used by EPA include those benchmarks 

identified as part of the GKM Release Incident emergency response and other water 

quality standards that apply. 

Objective B: Assess only current conditions of the Animas River, San Juan River, and Lake Powell at 

locations in Colorado, Southern Ute Reservation, New Mexico, Ute Mountain Ute Reservation, Navajo 

Nation, and Utah at sites in which historic or pre-release data are absent or limited. Data solely collected 

to meet Objective B will not be sufficient in assessing the changes since the GKM Release Incident 

without additional information. 

At stations that lack historical or pre-release data, a general assessment is proposed for Cement Creek, 

Animas River, San Juan River and including Lake Powell. The general assessment will not identify 

changes since the release but can be used to better understand overall conditions at these sites, which 

reflect all previous releases, discharges, spills, stormwater runoff and erosion over previous decades. 

Assessment Objective B: 

Identify current conditions of Cement Creek, Animas River, San Juan River and Lake Powell through 

the collection of surface water, sediment, and biological samples at multiple locations. 

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Post-Gold King Mine Release Incident Conceptual Monitoring Plan 

For Surface Water, Sediments and Biology 

Study Questions – Objective B: 

1. Do surface water and sediment in Cement Creek, Animas River, San Juan River and Lake Powell 

demonstrate exceedances of current criteria for metals and/or screening levels? 

a. What are current metals in water concentrations and how do they compare to state 

water quality standards and/or screening levels? 

b. What are current metals in sediment concentrations and how do they compare to 

recreational screening levels? 

c. What is the current assessment of biological communities (macroinvertebrates and fish) 

for locations in which State/Tribal assessment methods are available? 

d. How do current assessments compare to previous assessments (if available)? 

IV. Monitoring Frequency and Analytes of Interest 

The EPA anticipates that the sampling under this strategy will occur during the first year after 

completion of the GKM Release Incident response monitoring activities conclude. This monitoring and 

assessment effort will end after approximately one year if data confirm that pre-release trends or 

screening levels are maintained. A one-year monitoring duration was selected so that data may be 

collected across the full range of seasonal flow conditions. After completing one-year of monitoring 

under this plan, if results indicate a return to pre-release/historic trends, monitoring efforts under this 

plan will end and routine monitoring will continue per State, Tribal, and Federal program strategies and 

priorities. If pre-release trends are not attained and screening levels are exceeded, monitoring activities 

will be focused site specifically on areas of interest with the purpose of identifying sources and 

developing corrective actions. Potential sampling locations are identified below in Table 2, Section VI. 

Table 1 summarizes the expected frequency of monitoring under this plan as well as the type of data to 

be collected. The full suite of metals that were monitored during the emergency response will be 

monitored under this strategy for consistency. However, not all of the metals monitored during the 

emergency response (and through this effort) are expected to be present in the GKM discharge. The 

primary metals of interest associated with the GKM include: aluminum, cadmium, copper, iron, lead, 

manganese, and zinc. 

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Post-Gold King Mine Release Incident Conceptual Monitoring Plan 

For Surface Water, Sediments and Biology 

Table 1. Sampling and Monitoring Schedule For Potential Sampling Sites Listed in Table 2

SAMPLING AND MONITORING FALL MARCH SPRING/ SUMMER FALL

SCHEDULE: 2015 2016 JUNE 2016 2016 

2016 

WATER COLUMN - dissolved and total 1 event 1 event: 1 event: 1 event:

recoverable metals1, dissolved organic pre-snow snowmelt low flow 

carbon (DOC), total organic carbon melt runoff 

(TOC), hardness

SEDIMENT – total recoverable metals 1 event 1 event: 1 event: low 

pre-snow flow 

melt 

BENTHOS AND FISH TISSUE – metals; 1 event:

Collect and assess in locations where timeframe 

historic data are available so that comparable to 

release effects can be assessed. historic data 

BIOLOGICAL COMMUNITY – benthic 1 event 1 event

macroinvertebrate and fish populations 

– Collect and assess in locations where 

historic data are available and 

State/Tribal assessment methods are 

developed so that release effects can 

be assessed. 

STORMWATER SAMPLING - dissolved 1-2 (total 1-2 (total 

and total recoverable metals1 and across Fall across Fall 

dissolved organic carbon (DOC) – 2015 and 2015 and 

Collect at sites on Animas in CO, Summer Summer 

Southern Ute, NM 2016) 2016) 

PHYSICAL HABITAT Collected once at each site sampled for macroinvertebrates and fish –

likely at fall event 

FIELD PARAMETERS – All sampling events will include field parameters (pH, temperature, 

dissolved oxygen (DO), conductivity and turbidity) measured with a 

probe/sonde. 

FLOW – Flow data will be measured via stream gage if present or by flow meter 

for all events. 1 Aluminum, antimony, arsenic, barium, beryllium, cadmium, calcium, chromium, cobalt, copper, iron, lead, 

magnesium, manganese, mercury, molybdenum, nickel, potassium, selenium, silver, sodium, thallium, uranium, 

vanadium, and zinc 

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Post-Gold King Mine Release Incident Conceptual Monitoring Plan 

For Surface Water, Sediments and Biology 

V. Site Selection and Assessment Approach 

The following summarizes the site selection and general assessment approach for the watershed.

Sampling and monitoring location selection: 

Currently, the EPA has identified 23 potential monitoring locations along Cement Creek, the Animas 

River, the San Juan River, and Lake Powell based upon locations used in the emergency response and 

long-term data availability. Reference/background sites necessary for state or tribal assessments may be 

necessary and require stakeholder input for identification. The detailed list of potential sampling 

locations is provided in Section VI, Table 2. 

Assessment Summary: 

For data interpretation, post-release monitoring data will be compared against historic data, pre-release 

metals levels, risk-based screening levels and/or applicable water quality standards. Biological 

community information will be compared against pre-release/historic data using State/Tribal 

assessment methods. Data assessment methods will be developed for each site based upon the quantity 

and quality of the historic data. For sites with more abundant historic data, a statistical analysis of preand post-release conditions may be possible. Sites with limited historic data may not be suitable for a 

statistical comparison of pre- and post-release conditions and may provide only a qualitative 

understanding of changes in water and sediment quality. For these sites, changes in impairment status 

under the Clean Water Act pre- and post-release may serve to inform whether further study is 

warranted for confirmation. It is anticipated that the following decision rules will apply: 

General Decision Rules (primarily to be based on metals concentrations in water and sediment): 

o If the one-year monitoring study indicates that pre-release water quality and 

sediment trends are similar to trends observed prior to the GKM release: 

• End monitoring under this plan and continue monitoring per State, Tribal, and 

Federal program strategies and priorities.; and 

• Communicate waterbody condition in comparison to water quality standards 

and/or screening level benchmarks to stakeholders. 

o If the one-year monitoring study indicates that pre-release water quality and 

sediment trends have degraded since the GKM release AND screening levels or water 

quality standards are exceeded: 

• The EPA will conduct additional site-specific investigations as appropriate and 

use its authorities to work with other federal agencies, States, Tribes, and local 

entities to address these problems. 

o If the monitoring data for any site cannot be compared to pre-release 

conditions/historic data: 

• Communicate waterbody condition in comparison to water quality standards 

and/or screening level benchmarks to stakeholders. Conditions will not be 

attributable to GKM Release Incident using these data alone. 

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Post-Gold King Mine Release Incident Conceptual Monitoring Plan 

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Screening Levels and Water Quality Standards: 

Screening levels that were used for the GKM Release Incident response decisions will be used in data 

assessment under this strategy as well. Federally approved applicable State and Tribal water quality 

standards can be found at: 

• State of Colorado – 

o ftp://ft.dphe.state.co.us/wqc/wqcc/Current%20Water%20Qualitly%20Standards/Curren 

tly%20Effective%20Standards/34_SanJuan_Effective_06-30-2015/34_2015(06)SBP.pdf

• Navajo Nation – 

o http://www.navajonationepa.org/Pdf%20files/Navajo%20Nation%20Surface%20Water 

%20Quality%20Standards%202007.pdf

• Southern Ute Tribe - 

o Contact the tribe - https://www.southernute-nsn.gov/environmental-programs/waterquality/ or EPA Region 8 – 303-312-6947 

• State of New Mexico – 

o http://164.64.110.239/nmac/parts/title20/20.006.0004.pdf

• State of Utah – 

o http://www.rules.utah.gov/publicat/code/r317/r317-002.htm

• Ute Mountain Ute Tribe – 

o http://www.utemountainuteenvironmental.org/umep/assets/File/Water/Surface%20W 

ater%20Standards/UMU_WQS_2011Revision_042011_supplimental.pdf

VI. Potential Sampling Locations 

Table 2 includes potential sampling locations for the monitoring described in this plan. Final site 

selection will be based upon the assessment needs and goals of EPA, key stakeholders and regulatory 

partners. Replacement sites with pre-release or historic data may also be considered. Section XI 

provides associated maps for these locations. Maps will be finalized once site selection is complete. 

Table 2. Potential site names, description and type

Site Name Latitude Longitude Description/Location Importance/Rationale 

CC48 (EPA) 37.819984 -107.663275 Cement Creek upstream of Silverton Historic, long-term data 

/ 09358550 record and release data 

(USGS) available 

A68 (EPA) / 37.811202 -107.659167 Animas River above Cement Creek in Reference condition for 

09358550 Silverton this release; historic, 

(USGS) long-term data record 

and release data 

available 

A72 (EPA) / 37.79027 -107.667578 Animas River at gage below Silverton, Historic, long-term and 

82 (WQCD) downstream of confluence with release data record 

/09359020 Mineral Creek available 

(USGS) /

3611 (RW)

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Post-Gold King Mine Release Incident Conceptual Monitoring Plan 

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A73 (EPA) / 

3442 (RW) 

A75D (EPA)

/ 3438 (RW)

Bakers

Bridge (EPA)

/ GKM02

(EPA) / 88

(RW)

9426

(WQCD) /

89 (RW)

32nd St. 

Bridge (EPA) 

/ 3577 (RW) 

/ 

3717591075 

20601 

(USGS) 

Animas – 

Rotary Park 

(EPA) / 91 

(RW) / 

09361500 

(USGS) 

GKM05 

(EPA) 

GKM01 

(EPA) / 

AR19-3 

(SUIT) / 

Purple Cliffs 

(EPA) / 

3713191075 

15001 

(USGS) / 

3430 (RW) / 

92 (RW) / 

NAR1 (SUIT) 

AR 7-2 

(SUIT) / 

NAR4 (SUIT) 

NAR 6 

(SUIT) 

37.72215833 -107.65482778 

37.59793424 -107.77532681 

37.454134 -107.801601 

37.38506 -107.83686 

37.299991 -107.868199 

37.280718 -107.876927 

37.268704 -107.885857 

37.221542 -107.859455 

37.084992 -107.878383 

37.024806 -107.8738 

Animas River upstream of Elk Creek 

Animas River upstream of Cascade 

Creek 

Animas River at Bakers Bridge (CO 

Hwy. 250) 

Animas River near Trimble at CO Hwy 

252 Bridge 

Animas River in Durango at 32nd St. 

Bridge 

Animas River at Rotary Park in Durango 

Animas River, south end of Durango 

near intersection of 160 and 550 above 

confluence with Lightner Creek 

Animas River at Southern Ute 

Reservation boundary 

Animas River above confluence with 

Florida River 

Animas River on Southern Ute 

Reservation just downstream of 

Heaven on Earth Road 

Historic, long-term data 

available; characterizes 

Animas before 

tributary influence 

Historic, long-term data 

record; characterizes 

Animas before 

tributary influence 

Historic, long-term and 

release data record 

available; pre-release 

water quality data 

available 

Historic, long-term data 

record available; midway between Bakers 

Bridge and Durango 

Historic, long-term and 

release data record 

available 

Historic, long-term and 

release data record 

available 

Release response site; 

unclear if long-term 

data available 

Release response site; 

at CO/S. Ute 

Reservation border 

Historic data available 

Long-term data 

available, pre-release 

data available 

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Post-Gold King Mine Release Incident Conceptual Monitoring Plan 

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ADW-022 

(EPA) 

ADW-010 

(EPA) / 

09364010 

(USGS / 

28.1 (NM) / 

27.8 (NM) 

FW-040 

(EPA) 

SJLP (EPA) 

SJFP (EPA) /

NMRM1005 (EPA) /

09367540

(USGS)

SJSR (EPA) /

09368000

(USGS)

SJ4C (EPA) /

09371010

(USGS /

4954000

(UT)

SJME (EPA)

/ UTR9-

0901 (EPA)

SJBB EPA) /

UTRM-1009

(EPA) /

4953250

(USGS)

SJIN (EPA) /

3712481103
­

95301

(USGS) /

5952590

(UT)

36.920559 -107.909909 

36.837463 -107.991684 

36.783635 -108.102111 

36.73588701 -108.2539868 

36.74815602 -108.4120157 

36.78162422 -108.6927838 

37.000777 -109.029577 

 37.21681097 -109.19615 

37.257527 -109.618941 

37.2536 -110.6632 

Animas River at the Aztec Domestic 

Water System Intake 

Animas River, mid-way between 

Southern Ute boundary and 

confluence with San Juan River 

Animas River at confluence with San 

Juan River 

San Juan River below confluence with 

Animas River 

San Juan River near Farmington, NM 

San Juan River near Shiprock, NM 

San Juan River just north of Four 

Corners on Ute Mountain Ute 

Reservation 

San Juan River near the confluence of 

McElmo Creek 

San Juan River at Bluff, UT 

Lake Powell site near San Juan inlet 

Pre-release data 

available 

Pre-release data 

available 

USGS historic data 

available 

Pre-release data 

available 

Pre-release data 

available; historic data 

(National Rivers and 

Streams Monitoring 

Assessment) available 

Pre-release data 

available 

Pre-release data 

available 

Historic data (National 

River and Streams 

Monitoring 

Assessment) available; 

pre-release data 

available 

Historic data available 

(National Rivers and 

Streams Monitoring 

Assessment and State 

of Utah); pre-release 

and response data 

available 

Lake Powell site 

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Table 3 identifies historic data availability by site data type. Data availability will be confirmed prior to 

final site selection. 

Table 3. Summary of historic data availability by site. Asterisks indicate immediately pre-release

data are available.

Water Benthic Macrocolumn - Sediment Fish tissue - tissue - invertebrate Fish 

Site metals - metals metals metals population population

CC48 Yes Yes TBD TBD TBD TBD

A68 Yes Yes TBD Yes Yes TBD

A72 Yes Yes TBD Yes Yes TBD

A73 Yes Yes TBD TBD TBD TBD

A75D Yes Yes TBD Yes Yes TBD

Bakers Bridge Yes* Yes TBD Yes Yes TBD

9426 Yes No No No Yes TBD

32nd St. Yes* Yes No No Yes TBD

Bridge

Animas – Yes Yes TBD TBD Yes TBD

Rotary Park

GKM05 Yes TBD No TBD TBD TBD

GKM01 Yes* TBD No TBD TBD TBD

AR7-2 Yes Yes TBD TBD Yes TBD

NAR6 Yes* TBD TBD TBD TBD TBD

ADW-022 TBD TBD TBD TBD TBD TBD

ADW-010 Yes* TBD TBD TBD TBD TBD

SJLP Yes* TBD TBD TBD TBD TBD

FW-040 TBD TBD TBD TBD TBD TBD

SJFP Yes* TBD Yes TBD Yes Yes

SJSR Yes* TBD TBD TBD TBD TBD

SJ4C Yes* TBD TBD TBD TBD TBD

SJME Yes* TBD Yes TBD Yes Yes

SJBB Yes* TBD Yes TBD Yes Yes

SJIN TBD TBD TBD TBD TBD TBD

VII. Methods 

The following analytical and field methods are proposed for sample collection and analysis under this 

monitoring strategy: 

1. Dissolved metals in water: 

• ICP-MS Dissolved Metals in Water (EPA 200.8) and ICP Dissolved Metals in Water (EPA 

200.7) 

2. Total recoverable metals in water: 

• ICP-MS Total Metals in Water (EPA 200.8) and ICP Total Metals in Water (EPA 200.7) 

12 
DRAFT 

Post-Gold King Mine Release Incident Conceptual Monitoring Plan 

For Surface Water, Sediments and Biology 

3. Mercury: 

• EPA 245.1 

4. Dissolved organic carbon (DOC): 

• EPA 415.2 

5. Total organic carbon (TOC): 

• EPA 415.1 

6. Hardness: 

• SM 2340B 

7. Total recoverable metals in sediment: 

• ICP-MS Total Metals in Soil (EPA 200.8) and ICP Total Metals in Soil (EPA 200.7) 

8. Field methods: 

• EPA Sampling Standard Operating Procedures: Emergency Response Team (ERT) Standard 

Operating Procedures (SOPs) for surface water and sediment. 

• EPA Region 8 Water Sampling Standard Operating Procedure (SOP) and Sediment Sampling 

SOP. 

• EPA ERT SOPs general website: http://www.epaosc.org/site/site_profile.aspx?site_id=2107

• Surface water sampling SOP: http://www.epaosc.org/sites/2107/files/2013-R00.pdf

• Sediment sampling SOP: http://www.epaosc.org/sites/2107/files/2016-R00.pdf

• Macroinvertebrate sampling options – methods may vary by location 

o Use method used for historical data collection for historical comparability 

o Use EPA’s National Rivers and Streams Survey Methods for longitudinal 

comparability 

• Fish community sampling options – methods may vary by location 

o Use method used for historic/pre-release data collection for pre-release/historic 

comparability 

o Use EPA’s National Rivers and Streams Survey Methods for longitudinal 

comparability 

• Habitat Assessment options – methods may vary by location 

o Use method used for historical data collection for historic comparability 

o EPA’s National River and Streams Survey Methods for longitudinal comparability 

• Fish tissue sampling – methods may vary by location 

o Use method used for historic data collection for historic comparability 

VIII. Quality Assurance/Quality Control 

A QAPP will be developed to describe the data quality objectives, the detailed sampling and analysis 

plan, field and laboratory quality control requirements, data handling and storage, standard operating 

procedures for field and laboratory activities, and other quality assurance requirements for this 

monitoring plan. This QAPP will conform to QA/R-5 EPA Requirements for Quality Assurance Project 

Plans. 

The EPA anticipates using a single, National Environmental Laboratory Accreditation Conference 

(NELAC)-accredited lab that conforms to American National Standard ASQ/ANSI E4 quality assurance 

systems. Split samples may be provided to a second accredited laboratory for analytical verification. 

13
DRAFT 

Post-Gold King Mine Release Incident Conceptual Monitoring Plan 

For Surface Water, Sediments and Biology 

IX. Data Management

The EPA anticipates using a single lab for metals analysis in order to facilitate data delivery and sharing. 

We also anticipate using an online SCRIBE database to share data and uploading the data to the EPA’s 

STORET data warehouse for long-term storage. 

X. Data Assessment 

Objective A of this monitoring effort is to identify changes in metals concentrations in surface water and 

sediment since the GKM Release Incident in Cement Creek, Animas River, and San Juan River for at least 

one year after the end of the emergency response. Data assessment is described generally in Section V. 

Additional detail regarding data assessment approaches will be included in the Quality Assurance Project 

Plan and Sampling and Analysis Plan. Data assessment methods will be developed for each site based 

upon the quantity and quality of the historic data. For sites with more abundant historic data, a 

statistical analysis of pre- and post-release conditions may be possible. Sites with limited historic data 

may not be suitable for a statistical comparison of pre- and post-release conditions and may provide 

only a qualitative understanding of changes in water and sediment quality. For these sites, changes in 

impairment status under the Clean Water Act may serve to inform whether further study is warranted. 

When completing condition assessments for either Objective A or Objective B, State and tribal 

assessment methods will be considered in assessing data against water quality standards. Available 

assessment methods include the following: 

• State of Colorado – 

o https://www.colorado.gov/pacific/sites/default/files/303dLM2016.pdf

• State of New Mexico – 

o https://www.env.nm.gov/swqb/protocols/documents/2016_FINAL_AP_062215.pdf

• State of Utah – 

o http://www.deq.utah.gov/ProgramsServices/programs/water/wqmanagement/assessm 

ent/docs/2015/03Mar/303d_AsseesmentMethodology.pdf

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DRAFT 

Post-Gold King Mine Release Incident Conceptual Monitoring Plan 

For Surface Water, Sediments and Biology 

XI. Figures 

[Page intentionally blank. Figures follow below.] 

15 
Post Gold King Mine Release Incident:

Conceptual Monitoring Plan for

Surface Water, Sediments, and Biology ­

Potential Sampling Sites
 

Utah 

SJIN Navajo 

SJBB

Lake Powell UTRM-1009 

SJME SJ4C

UTR9-0901 

Legend
 Arizona Navajo
 

! Potential Sampling Sites 

" Pre-release Sampling Sites San Juan River 

# NRSA Historic Sites 

Colorado 

Gold King

Mine 

Ute

Mountai

Ute 

n 

Southern Ute 

SJSR 

Animas River 

ADW-022 Navajo
 

SJLP
 FW-040 SJFP ADW-010

NMRM-1005 New Mexico 

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Incident: Conceptual Monitoring Gold King Plan for Surface Water, Mine

Sediments, and Biology ­ CC48 Potential Sampling Sites 

A68

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9426 WQCD 

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" Pre-release Sampling Sites 

# EPA Historic Sampling Sites 

GKM05 Animas-Rotary Park 

GKM01 

Southern Ute

AR7-2 

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