IN THE UNITED STATES DISTRICT COURT FOR THE DISTRICT …...E-mail: [email protected] *Counsel of...

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IN THE UNITED STATES DISTRICT COURT FOR THE DISTRICT OF COLORADO

Chief Judge Marcia S. Krieger

Civil Action No. 14-cv-01153-MSK-KLM WILDEARTH GUARDIANS, Plaintiff, v. IRG BAYAUD, LLC, BRENT ANDERSON, and CITY AND COUNTY OF DENVER, Defendants.

ORDER ON MOTION FOR ENTRY OF CONSENT DECREE

THIS MATTER comes before the Court on the Joint Motion for Order Entering Consent

Decree (# 140). Attached to the Motion is the parties’ proposed Consent Decree (# 140-1).

Plaintiff, WildEarth Guardians, and Plaintiff-Intervenor, the Colorado Department of

Public Health and Environment (CDPHE) asserted claims against Defendants for violation of the

Clean Water Act, 33 U.S.C. § 1251, et seq. and the Resource Conservation and Recovery Act, 42

U.S.C. § 6901, et seq. On April 27, 2017 the parties filed their Motion for Entry of Consent

Decree, in which the parties represent that the Consent Decree resolves all claims.

Having had the opportunity to review the Consent Decree, the Court makes the following

observations. First, the Consent Decree is fundamentally an Agreement between the parties, not a

recitation of any findings that the Court has made following an adversarial presentation of

contested issues. This is particularly significant insofar as the final paragraph of Part I purports to

have the Court “Adjudge[ and] Order[ ]” all of the ensuring paragraphs. The Court has not made

Case 1:14-cv-01153-MSK-KLM Document 141 Filed 05/17/17 USDC Colorado of 3

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the findings contained in the Consent Decree, with the exception of a finding that the parties have

mutually agreed to be bound by all of the representations contained in the proposed Consent

Decree. Therefore, the Court enters the proposed Decree solely as an agreement between the

parties, not as containing any further judicial findings or orders.

Second, the Consent Decree seeks inconsistent relief. In Paragraphs 35a of the Consent

Decree (and Paragraph 11 of the Motion), the parties seek “dismissal, with prejudice, of

Guardian’s Second Amended Complaint and of the Division’s complaint upon intervention.” The

applicable Rule for such dismissal is Fed. R. Civ. P. 41(a)(2). However, in Paragraph 56 of the

Consent Decree, the parties seek “a final judgment of the Court” under Fed. R. Civ. P. 54.1

Because the Court cannot give effect to both of those provisions, it adopts Paragraph 35a and

rejects Paragraph 56. Dismissal of all claims, with prejudice, will enter pursuant to Fed. R. Civ. P.

41(a)(2).

The Court hereby GRANTS the Motion For Entry of Consent Decree, and subject to the

limitations above, approves the proposed Consent Decree (#140-1). All claims is this action are

DISMISSED with prejudice pursuant to Fed. R. Civ. P. 42(a)(2), and the Clerk of Court shall

close this case.

DATED this 17th day of May, 2017.

BY THE COURT:

1 Although both means result in closure of a case, and both result in entry of final judgment, the effect of the two judgments differs. When dismissal is pursuant to Rule 41(a)(2), the Court will not retain jurisdiction to enforce a settlement agreement. See Kokkonen v. Guardian Life Ins. Co. of Am., 511 U.S. 375, 377 (1994). Rule 54, on the other hand, allows the parties to request a stipulated judgment and in some instances, retention of jurisdiction over compliance with that judgment exists.


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Marcia S. Krieger Chief United States District Judge



Civil Action No. 1:14-cv-01153-MSK-KLM

WILDEARTH GUARDIANS,

Plaintiff,

COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, WATER QUALITY CONTROL DIVISION,

Intervenor Plaintiff,

v.

IRG BAYAUD, LLC, a Colorado limited liability company; BRENT ANDERSON; an individual; and THE CITY AND COUNTY OF DENVER, a home rule municipality.

Defendants.

JOINT MOTION TO ENTER CONSENT DECREE

Plaintiff WildEarth Guardians (“Guardians”), Plaintiff-Intervenor the Colorado

Department of Public Health and Environment, Water Quality Control Division (“Division”),

Defendants IRG Bayaud, LLC (“IRG”) and Brent Anderson, and Defendant City and County of

Denver (“Denver”), by and through their undersigned counsel, hereby move for approval and

entry of the Consent Decree that was previously lodged with the Court. In support of this

motion, the parties state as follows:

1. In this action, the Plaintiff asserted claims pursuant to citizen suit provisions of

the Clean Water Act (“CWA”) and the Resource Conservation and Recovery Act (“RCRA”).

The claims arose out of alleged pollution conditions in groundwater and in the South Platte River.

The claims included assertions of violations of a Permit issued to IRG Bayaud under the CWA

Case 1:14-cv-01153-MSK-KLM Document 140 Filed 04/28/17 USDC Colorado Page 1 of 7

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by the Division. The property that is the focus of this action is now owned by the City and

County of Denver.

2. In November 2016, the Division was granted leave to intervene in this action for

the limited purpose of joining in Guardians’ First Claim for Relief, on the terms set forth in the

Division’s November 3, 2016 notice to this Court.

3. On March 13, 2017, the parties gave the Court notice of a final settlement of their

claims and lodged a proposed Consent Decree with the Court. See Dkt. # 137. The lodged

Decree completely resolves the claims in this case and the state court case.

4. On March 13, 2017, pursuant to the CWA, the Consent Decree was submitted to

the Attorney General of the United States and the Administrator of the United States

Environmental Protection Agency (collectively “United States”) for a statutorily-mandated forty-

five (45) day review period (through April 27, 2017). See 33 U.S.C. § 1365(c)(3).

5. On April 14, 2017, the United States filed a letter notifying the Court that it has

reviewed the proposed Consent Decree and has no objection to its entry. See Dkt. # 139.

6. The only other prerequisite to requesting entry of the Consent Decree –

termination of IRG Bayaud’s water quality permit by the Division – has also been satisfied. On

April 17, 2017, following a thirty (30) day public comment period (during which no public

comments were received), the Division issued its final decision terminating IRG’s Permit No.

CO0046329. There is no need for further delay in entering the Consent Decree, as all conditions

precedent have been satisfied.


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7. On April 6, 2017, this Court vacated the trial and directed the parties to move for

a final order approving the terms of the Consent Decree and closing the case no later than April

28, 2017. Dkt. # 138.

8. The parties now move for approval and entry of the Consent Decree that was

previously lodged with the Court. See Dkt. # 137, Attachments 1-6. This Consent Decree is also

attached to this motion. See Attachments 1-6.

9. The parties acknowledge that the Consent Decree recites factual findings upon

which the parties agree, but that this Court has not made any factual findings in this case. The

parties also acknowledge that the terms of the Consent Decree setting forth obligations of the

parties constitute agreements of the parties.

10. Article XIV of the Consent Decree sets forth a dispute resolution process that

requires the parties to seek resolution of disputes relating to the Consent Decree amongst

themselves, but that ultimately allows for submission of disputes to the Court. Based on footnote

2 of the Order Vacating Trial Pending Approval of the Parties’ Consent Decree, the parties

propose that the Court modify the Consent Decree by modifying Paragraph 43 as described in

subparagraph a. below, striking Paragraphs 47 through 49, and providing as set forth in

subparagraphs b. through e. below:

a. Paragraph 43 of the Consent Decree is modified to provide that the dispute

resolution terms of Article XIV. shall be the exclusive mechanism to

resolve disputes arising under or with respect to this Decree, except for

disputes asserting breach of the payment obligations set forth in

Paragraphs 24 and 29 of the Consent Decree.


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b. After complying with the procedures set forth in Paragraphs 43 through 46

of the Consent Decree, excluding filing a motion for judicial review, the

Defendants may seek judicial review of the dispute as a new proceeding in

a court of appropriate jurisdiction.

c. A proceeding for judicial review shall be commenced within fourteen (14)

days of receipt of the Division’s Statement of Position pursuant to

Paragraph 46 of the Consent Decree. The complaint shall set forth the

Defendant(s) position on the matter in dispute, including any supporting

factual data, analysis, opinion, or documentation, and shall set forth the

relief requested.

d. For disputes pertaining to the adequacy or appropriateness of plans,

procedures to implement plans, schedules or any other items requiring

approval or a determination by the Division under the Consent Decree, the

Division’s Statement of Position pursuant to Paragraph 46 shall be deemed

final agency action and shall be reviewed pursuant to C.R.S. § 24-4-106.

The Consent Decree shall be a part of the record in any such proceeding.

e. Except as otherwise provided in the Consent Decree, in any other dispute,

the Defendant(s) shall bear the burden of demonstrating that its position

complies with the Consent Decree and furthers the objectives of the

Consent Decree.


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11. If entered, the Consent Decree shall cause dismissal, with prejudice, of

Guardian’s Second Amended Complaint and of the Division’s complaint upon intervention.

The parties therefore request that this case be closed.

Respectfully submitted this 28th day of April, 2017,

s/ Ashley Wilmes Ashley Wilmes

1328 Prather Road Lexington, KY 40502 Telephone: (859) 312-4162 E-mail: [email protected]

s/ R. Scott Jerger

R. Scott Jerger Field Jerger LLP 621 SW Morrison, Ste. 1225 Portland, OR 97205 Telephone: (503) 228-9115 FAX: (503) 225-0276 E-mail: [email protected] s/ Brent Foster Brent Foster 767 12th Street, Suite 248 Hood River, OR 97301 Email: [email protected]

Attorneys for Plaintiff WildEarth Guardians

s/ Scott A. Clark Scott A. Clark BURNS, FIGA & WILL, P.C. 6400 S. Fiddler’s Green Circle, Suite 1000 Greenwood Village, CO 80111 Phone Number: 303-796-2626 Fax Number: 303-796-2777 E-mails: [email protected]

Attorneys for Defendants IRG Bayaud, LLC and Brent Anderson


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s/ Jessica Brody Shaun Sullivan Jessica Brody Nathan Lucero Denver City Attorney’s Office Municipal Operations Section 201 West Colfax Avenue, Dept. No. 1207 Denver, Colorado 80202 Telephone: (720) 913-3267 FAX: (720) 913-3280 E-mail: [email protected] [email protected] [email protected] Attorneys for Defendant City and County of Denver CYNTHIA H. COFFMAN Attorney General s/ Ellen H. Kutzer Ellen Howard Kutzer, Assistant Attorney General Margaret Parish, Assistant Attorney General Jerry W. Goad, First Assistant Attorney General Natural Resources and Environment Section 1300 Broadway, 7th Floor Denver, Colorado 80203 Telephone: (303) 866-5128 FAX: (303) 866-3558 E-mail: [email protected] *Counsel of Record Attorneys for Proposed Plaintiff-Intervenor Colorado Department of Public Health and Environment, Water Quality Control Division


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CERTIFICATE OF SERVICE

I hereby certify that on the 28th day of April 2017, I electronically filed the foregoing with the Clerk of Court using the CM/ECF system, and I served a true copy on the following parties through their attorneys via the Court’s CM/ECF filing system: Scott A. Clark BURNS, FIGA & WILL, P.C. 6400 Fiddler’s Green Circle, Suite 1000 Greenwood Village, CO 80111 [email protected] Attorneys for Defendants IRG Bayaud, LLC and Brent Anderson Jessica Brody Shaun Sullivan Katherine Wilmoth Nathan J. Lucero Denver City Attorney’s Office Municipal Operations Section 201 West Colfax Ave., Dept. No. 1207 Denver, Colorado 80202 [email protected] [email protected] [email protected] Attorneys for the City and County of Denver Ellen Howard Kutzer, Assistant Attorney General Margaret Parish, Assistant Attorney General Natural Resources and Environment Section 1300 Broadway, 7th Floor Denver, Colorado 80203 [email protected] Attorneys for Proposed Plaintiff-Intervenor Colorado Department of Public Health and Environment, Water Quality Control Division

/s/ Ashley Wilmes Ashley Wilmes Attorney for Plaintiff



Civil Action No. 1:14-cv-01153-MSK-KLM

WILDEARTH GUARDIANS,

Plaintiff,

COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, WATER QUALITY CONTROL DIVISION,

Intervenor Plaintiff,

v.

IRG BAYAUD, LLC, a Colorado limited liability company; BRENT ANDERSON; an individual; and THE CITY AND COUNTY OF DENVER, a home rule municipality.

Defendants.

CONSENT DECREE

I. BACKGROUND

A. Plaintiff WildEarth Guardians (“Guardians” or “Plaintiff”) has asserted claims

against the Defendants, IRG Bayaud, LLC (“IRG Bayaud”), Brent Anderson and the City and

County of Denver (“Denver”), pursuant to the citizen suit provisions of the Clean Water Act

(“CWA”) and the Resource Conservation and Recovery Act (“RCRA”). Guardians’ claims

relate to groundwater conditions beneath a property known as 1271 W. Bayaud Avenue, Denver,

Colorado 80223 (the “Site”).

B. In 2006, Intervenor Plaintiff the Colorado Department of Public Health and

Environment, Water Quality Control Division (“Division”) issued Colorado Discharge Permit

System Permit Number CO-0046329 (the “Permit”) to the then-owner of the Site.

Case 1:14-cv-01153-MSK-KLM Document 140-1 Filed 04/28/17 USDC Colorado Page 1 of 33

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C. Pursuant to an agreement with Denver, Defendant IRG Bayaud took ownership

of the Site in about 2008 for the purpose of implementing a clean-up plan to address the mine

rock fill and groundwater conditions that existed as a result of historical operations on the Site

and developing the Site for Denver’s use. After taking ownership of the Site, the Permit was

transferred to IRG Bayaud.

D. Beginning in about 2008, IRG Bayaud undertook cleanup of the legacy mine

rock and groundwater conditions at the Site. That work implemented a Voluntary Cleanup Plan

(“VCUP Plan”) approved by the Colorado Department of Public Health and Environment,

Hazardous Materials and Waste Management Division pursuant to the Colorado Voluntary

Clean-up and Redevelopment Act, C.R.S. § 25-16-301, et seq. IRG Bayaud completed

construction activities called for in the VCUP Plan and then, in about 2009, transferred the Site

to Denver.

E. Pursuant to the CWA, 33 U.S.C. § 1365(b)(1)(A), Plaintiff provided written

notice to IRG Bayaud, LLC, Brent Anderson, the Administrator of the United States

Environmental Protection Agency (“EPA”), the Administrator of EPA Region 8, and the

Division Director, by letter postmarked October 17, 2013, of its intent to sue IRG Bayaud, LLC

its Chief Executive Officer, Brent Anderson and Project Manager John Yerton, for alleged

violations of the CWA, 33 U.S.C. § 1251, et seq.

F. On April 23, 2014, Plaintiff filed a Complaint for declaratory and injunctive relief

against Defendants IRG Bayaud and its Chief Executive Officer, Brent Anderson, pursuant to the

citizen suit provision of the CWA which alleged violations of the Permit.


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G. On August 19, 2014, Plaintiff filed its Second Amended Complaint for

declaratory and injunctive relief, which added a claim against Defendants the City and County of

Denver, IRG Bayaud and Brent Anderson for alleged violations of RCRA, 42 U.S.C. §

6972(a)(1)(B).

H. Plaintiff’s claims relate to alleged pollution conditions, including in particular

dissolved arsenic in groundwater that Plaintiff asserts may discharge to the South Platte River.

I. Beginning in about 2008, and from time to time since then, IRG Bayaud has

sought to end the Permit. Each time, the Division has concluded that IRG Bayaud did not

provide appropriate information to terminate the Permit in accordance with 5 CCR 1002.61,

Regulation 61.8(8) and Division policy or that IRG Bayaud did not use the appropriate

administrative mechanism to terminate the permit.

J. In January 2014, IRG Bayaud submitted to the Division a Notice of Withdrawal

of its Permit renewal application. IRG Bayaud subsequently sought judicial confirmation that

the Permit had expired in IRG Bayaud, LLC v. CDPHE, Case No. 2014 CV 32636, District Court

for the City and County of Denver. After briefing and oral argument, the Denver District Court

held that the Permit did not expire when IRG Bayaud filed its Notice of Withdrawal. IRG

Bayaud has appealed that decision to the Colorado Court of Appeals in Case No. 15 CA 1487

(“State Appeal”). Briefing in that appeal has not commenced and proceedings have been stayed

pending approval and implementation of this Consent Decree (“Decree”).

K. In November 2016, the Division was granted leave to intervene in this action for

the limited purpose of joining in Guardians’ First Claim for Relief, on the terms set forth in the

Division’s November 3, 2016 notice to this Court.


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L. In November 2016, the Division issued Notice of Violation / Cease and Desist /

Clean-up Order Number: IO-161102-1 to both IRG Bayaud and Denver (“Cleanup Order”). The

Cleanup Order compels IRG Bayaud and Denver to implement groundwater, surface water

(South Platte River), and soil sampling programs that are intended to evaluate the fate and

transport of pollutants, arsenic in particular, found in groundwater beneath the Site. IRG Bayaud

and Denver dispute the legal and factual basis for the Cleanup Order and have requested a

hearing to contest the same.

M. In defense to the various allegations of Guardians and the Division, the

Defendants assert, among other things, that there has not been, and that there is not a threat of,

any discharge of arsenic from the Site to the South Platte River.

N. The Parties have engaged in discussions relating to the potential settlement of this

litigation and related proceedings before the Colorado Court of Appeals and the Division, which

discussions have included an assessment of the facts surrounding the alleged violations and

current Site conditions.

O. The Parties agree that settlement of those matters is in the best interest of the

Parties and the public, and that entry of this Decree without additional litigation is the most fair,

reasonable, and appropriate means of addressing the potential contamination and environmental

harms alleged in Plaintiff’s Second Amended Complaint and in the Cleanup Order and to resolve

this and all related actions.

P. The Parties consent to the entry of this Decree without further trial, argument, or

appeal.


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Q. Pursuant to the CWA, 33 U.S.C. § 1365(c)(3), this Decree is being forwarded to

the United States Department of Justice (“DOJ”) and to the United States Environmental

Protection Agency (“EPA”) for the statutorily-mandated forty-five (45) day review period.

NOW, THEREFORE, with the consent of the Parties and without any admission or

adjudication of the violations, claims or facts alleged in the Second Amended Complaint, the

Notice Letters, the State Appeal or the Cleanup Order, IT IS HEREBY ADJUDGED,

ORDERED, AND DECREED as follows:

II. JURISDICTION AND VENUE

1. This Court has jurisdiction over the Parties and the subject matter pursuant to

28 U.S.C. § 1331 (federal question), 33 U.S.C. § 1365(a) (citizen suit provision of the CWA),

and 42 U.S.C. § 6972(a)(1) (citizen suit provision of RCRA).

2. Venue is proper in this judicial district under 28 U.S.C. § 1391(b)(2), 33 U.S.C.

§ 1365(c) (CWA), and 42 U.S.C. § 6972(a) (RCRA).

3. The Parties waive all objections and defenses that they may have to jurisdiction of

the Court or to venue in this District for the purposes of this Decree.

III. PARTIES BOUND

4. This Decree applies to and is binding upon Guardians, the Division, IRG Bayaud,

Brent Anderson and Denver (each a “Party” and collectively the “Parties”) and their successors

and assigns. The execution of this Decree and all actions taken pursuant to this Decree shall not,

under any circumstances, constitute or be construed as an admission by any Party of any fact or

liability or a concession of any question of law with respect to the Site or with respect to any

pollutant or any solid or hazardous waste allegedly discharged, contributed to or released at, to or


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from the Site. This Decree shall not constitute admissible evidence in any proceeding except in

an action to seek enforcement of any terms herein.

IV. TERMINATION OF THE PERMIT

5. The Defendants’ obligations under this Decree are contingent upon final agency

action terminating of the Permit.

6. Within three days of lodging this Decree with the Court, the Division will issue

and provide public notice, pursuant to 5 CCR 1002-61, Regulation 61.8(8)(c) of a draft decision

to terminate the Permit, which shall be substantially consistent with the Draft Termination

Decision attached hereto as Exhibit A.

7. Guardians will not object to the Draft Termination Decision in any way, nor will

it encourage others to do so.

8. Pursuant to 5 CCR 1002-61, § 61.8(8)(c), the Division will allow a period of

thirty (30) days from the public notice of the Draft Termination Decision for public comment in

accordance with 5 CCR 1002-61, § 61.5(2). Within three calendar days after completion of the

required public comment period, the Division will either take final agency action to terminate the

Permit or advise the Parties that it cannot terminate the Permit. If the Division determines, for

any reason, that it cannot terminate the Permit, this Decree will not be entered, will terminate,

and will be of no further force and effect. The Division shall provide the Court written notice of

its final agency action terminating the Permit within three (3) days after the close of the public

comment period.

9. No later than three (3) days following: 1) the final agency action terminating the

Permit, and 2) the United States’ 45-day review period, as set forth in Paragraph 33 of this


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Decree, the Parties shall submit a joint motion to the Court requesting signature and final entry

of this Decree.

V. DECISIONS REGARDING ANY RESPONSE ACTION AT THE SITE

10. Background. At Defendants’ request, Dr. David Lipson performed a fate and

transport analysis entitled Evaluation of Potential Arsenic Transport in Groundwater, dated

October 27, 2016, a copy of which is attached hereto as Exhibit B (“October 2016 Evaluation”).

The October 2016 Evaluation was conducted to estimate whether and to what extent arsenic in

Site groundwater is mobile and whether there are, or are likely to be in the future, impacts to the

South Platte River from arsenic within the Site. The Parties agree that the October 2016

Evaluation presents a reasoned hypothesis about the fate and transport of arsenic at the Site.

11. Denver and IRG Bayaud will be jointly and severally responsible for

implementing the monitoring program described below. The purpose and focus of this

monitoring program is to support a determination as to whether there are, or are likely to be in

the future, adverse impacts to the South Platte River from arsenic beneath the Site. In particular,

the monitoring program is intended to collect data upon which expert analysis will be performed

to estimate: 1) Whether and to what extent elevated arsenic detected in Site groundwater samples

are mobile and potentially migrating offsite; and 2) Whether and to what extent elevated arsenic

concentrations in Site groundwater samples may pose an imminent and substantial threat to the

South Platte River. The groundwater and surface water quality monitoring programs

implemented pursuant to this Decree will be for a period not to exceed three (3) years.

12. Groundwater Monitoring and Evaluation. The groundwater monitoring

program shall be as follows:


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a. Monitoring Well Locations. Groundwater monitoring shall occur at the

following locations:

i. Existing monitoring wells OFF-4, MW-19S, MW-19M, and MW-19D, the

locations of which are shown on Exhibit C;

ii. New monitoring wells, designated MW-21S, MW-21M, MW-21D, MW-

22S, MW-22M, MW-22D, MW-23S, MW-23M, and MW23D, to be

installed along the northern Site boundary in the approximate locations

shown on Exhibit C; and

iii. New groundwater monitoring wells, designated MW-24S and MW-24M,

to be installed in the approximate location shown on Exhibit C. If

practical constraints prevent the installation of MW-24S and/or MW-24M,

such as drill refusal using standard drilling techniques, the Parties agree to

confer as to an alternative location for MW-24S and/or MW-24M.

b. Monitoring Well Profiles. All new wells designated with an “S” shall be

screened from about two feet above the water table to about three feet below the water

table. All new wells designated with an “M” shall be screened at an interval consistent

with the screen in monitoring well MW-19M. All new wells designated with a “D” shall

be screened at an interval consistent with the screen in monitoring well MW-19D. All well

screen intervals will be subject to adjustment based on field observations at the time of

drilling. The Parties will consider modifications to well locations and/or well sampling

depths recommended by the third-party expert (defined below) as necessary.


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c. Groundwater Sampling Parameters. At each monitoring well, pH, oxidation

reduction potential (ORP), specific conductance, dissolved oxygen, static water level and

depth of sample data shall be collected in the field. Groundwater samples shall be

collected from each monitoring well and analyzed for dissolved arsenic, total recoverable

arsenic, and dissolved cadmium.

d. Monitoring Protocol. Sample collection and laboratory analysis shall be

conducted in accordance with the methods specified in 40 C.F.R. Part 136. The practical

quantitation limits (PQLs) or reporting limits (RLs) shall be consistent with Division

policy.

e. Data Submission. Denver and IRG Bayaud shall submit the results of the

monthly monitoring electronically to the Division and Guardians within five (5)

calendar days after receipt of the results.

f. Monitoring Frequency and Duration. Monitoring shall be conducted monthly

for a minimum of twelve (12) consecutive months, not to exceed thirty-six (36) months.

Following receipt of and based on the Year One Report (defined below), the Division shall

determine the monitoring frequency (not to exceed monthly) that is needed to continue to

evaluate potential adverse impacts to the South Platte River from arsenic beneath the Site

(“Monitoring Frequency Determination”). If the Division fails to make a Monitoring

Frequency Determination within thirty (30) days after submission of the Year One Report,

monitoring frequency shall decrease to quarterly unless and until such time as the Division

makes a different determination.


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g. Commencement of Monitoring. Sample collection shall commence no later

than sixty (60) days following entry of this Decree.

13. Borehole Soil Sampling. Soil samples will be collected from the borings for the

new wells MW-21D, MW-22D, and MW-23D. Soil profiles shall be logged using standard

borehole logging techniques. The soil from the borings shall be analyzed as follows:

a. Samples shall be collected two feet above and below the top of groundwater table,

and every two feet to the ground surface;

b. Samples shall be analyzed for total arsenic, total cadmium, and total iron.

c. Denver and IRG Bayaud shall submit the results of the soil sample analysis

electronically to the Division and Guardians within five (5) calendar days after receipt of

the results.

14. Surface Water Monitoring. The surface water monitoring program shall be as

follows:

a. Monitoring Locations. Surface water monitoring shall occur at the following

locations in the South Platte River: N1, N4A, N4B and N7, as those approximate locations

are shown on Exhibit B, Figure 1. The sample collected at monitoring location N7 will be

a composite sample collected from four aliquots, spaced at approximately equal distances

apart, along a transect across the river, except to the extent limited by safety concerns in the

judgment of the field personnel.

b. Monitoring Parameters. At each monitoring location, pH, ORP, temperature,

specific conductance and dissolved oxygen data will be collected in the field. Surface


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water samples will be collected at each location and analyzed for dissolved arsenic, total

arsenic, and dissolved cadmium.

c. Sample Analysis Plan. A sample analysis plan for the surface water monitoring,

describing the sample collection techniques, calibration of field measuring devices, sample

preservation and chain of custody requirements, and the laboratory analytical

methodologies, shall be developed by Denver and IRG Bayaud and provided to the

Division.

d. Sampling Protocol. Sample collection and laboratory analysis shall be

conducted in accordance with the methods specified in 40 C.F.R. Part 136. The PQLs or

RLs shall be consistent with Division policy.

e. Data Submission. IRG Bayaud and Denver shall submit the results of the

monthly monitoring electronically to the Division and Guardians within five (5)

calendar days of receipt of the results.

f. Frequency of Monitoring. Monitoring shall be conducted monthly for a

minimum of twelve (12) consecutive months, not to exceed thirty-six (36) months.

Following receipt of and based on the Year One Report (defined below), the Division shall

determine the monitoring frequency (not to exceed monthly) that is needed to continue to

evaluate potential adverse impacts to the South Platte River from arsenic beneath the

Site. If the Division fails to make a Monitoring Frequency Determination within thirty (30)

days after submission of the Year One Report, monitoring frequency shall decrease to

quarterly unless and until such time as the Division makes a different determination.


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g. Commencement of Monitoring. Sample collection shall commence no later

than sixty (60) days following entry of this Decree.

15. Site Evaluation Report. Denver and IRG Bayaud agree to the following

requirements as part of the monitoring program:

a. Expert Report Preparation. Denver and IRG Bayaud shall retain the services of

a third-party expert (“Expert”) who will review groundwater data collected during the first

twelve (12) months of monitoring, surface water data, and historical water quality data

from the Site to evaluate the fate and transport of arsenic located beneath the Site and to

provide a comparative analysis of the new groundwater data to the conclusions set forth in

the October 2016 Evaluation (“Year One Report”).

b. Report Timing. The Year One Report shall be submitted to the Division and

Guardians within four (4) months after completion of the first twelve (12) months of

groundwater monitoring.

c. Year One Report Determinations and Recommendations. The determinations

and recommendations reported in the Year One Report will be based on existing and newly

collected data and the professional judgment of the Expert, and will include expert

determinations and recommendations regarding the following:

i. The groundwater gradient;

ii. The mass of iron-oxide minerals in the alluvial aquifer beneath the Site

cap and following the groundwater gradient off-Site;


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iii. The mass of arsenic in groundwater and in saturated soils in the alluvial

aquifer beneath the Site cap and following the groundwater gradient off-

Site;

iv. The redox conditions beneath the Site cap and following the groundwater

gradient off-Site;

v. The potential flux of groundwater leaving the Site, using an appropriate

model selected by the Expert and agreed to by the Parties;

vi. The potential mass flux of arsenic leaving the Site by groundwater

transport;

vii. The potential rate of arsenic advancement and the potential extent of

advancement;

viii. The frequency of ongoing monitoring that may be required to meet the

goals identified in Paragraph 11, above;

ix. What, if any, ongoing and potential future impacts to the South Platte

River exist as a result of the contaminated material that remains beneath

the Site; and

x. Whether elevated arsenic concentrations in Site groundwater samples pose

an imminent and substantial threat to the South Platte River for which the

Expert recommends preparing and implementing a “Response Plan” (as

defined in Paragraph 17(c)).


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d. Year One Report Data Considerations. The determinations and

recommendations reported in the Year One Report will take into consideration the

following information:

i. All data collected by IRG Bayaud in accordance with the VCUP Plan;

ii. All South Platte River water data that has been collected by IRG Bayaud

and Denver;

iii. All data collected by IRG Bayaud pursuant to the terms of the Permit;

iv. All data collected pursuant to this Decree;

v. Groundwater flow rate and direction;

vi. South Platte River flow data at the nearest upstream and downstream river

gages, or flow measurements taken at N1 and N7 during sample

collection;

vii. The presence of geochemical barriers to arsenic migration and an

evaluation of how the barriers could change over time;

viii. Data trends;

ix. Remedial options aimed at reducing groundwater arsenic concentrations to

the maximum extent practicable to prevent an imminent and substantial

threat to the South Platte River (including but not limited to the

alternatives listed in the March 7, 2016 Evaluation of Potential Arsenic

Remedial Options in Groundwater prepared by Dr. Lipson, a copy of

which is attached hereto as Exhibit D); and


15

x. Other available and credible data related to arsenic contamination on the

Site or leaving the Site.

e. Expert Retention. Within sixty (60) days after entry of this Decree, Denver and

IRG Bayaud shall provide documentation to the Division that they have retained the

services of the Expert. The documentation shall include, at a minimum, a copy of the

Expert’s qualifications and a copy of the written contract or agreement for services,

including a copy of the scope of services to be provided. If the Division determines that

the selected Expert lacks the qualifications necessary to prepare the Year One Report, or

the scope of services is not adequate, the Division retains the right to disapprove of the

selected Expert. If the Division disapproves of the selected Expert, Denver and IRG

Bayaud shall provide documentation to the Division that a new individual or entity has

been retained to serve as the Expert within twenty (20) days of receiving notice of the

Division’s disapproval. The Division retains the right to disapprove of the secondarily

selected expert through the same processes outlined in this paragraph.

f. Supplemental Report. Within four (4) months of completion of the thirty-six

(36) month term of the monitoring program, Denver and IRG Bayaud will cause the Expert

to prepare a supplemental report updating, as necessary, the conclusions of the Year One

Report and will submit the Supplemental Report to the Division and Guardians.

16. Arsenic Compliance and Response Triggers. The Parties agree to the following

arsenic level compliance and response triggers and actions:

a. Response Plan Triggers. Denver and IRG Bayaud will submit a Response Plan

to the Division if:


16

i. Upon any single sampling event:

A. The dissolved arsenic concentration at N7, N4A, or N4B is more

than 3 µg/l; and

B. The dissolved arsenic concentration at N7, N4A, or N4B is at least

3 µg/L greater than observed in the same sampling event at N1; or

ii. If, pursuant to Paragraph 15(c)(x), a response plan is recommended by the

Expert in either the Year One Report or the Supplemental Report.

b. Notification. Denver and IRG Bayaud shall notify the Division and Guardians of

any condition that triggers development of a Response Plan pursuant to Paragraph 16(a)(i)

at the time they submit the laboratory data that demonstrates the condition. The notice

shall include a written summary of the data and any other relevant information relating to

the condition. Within fourteen (14) days of an identified condition requiring a response

plan pursuant to Paragraph 16(a)(i), or issuance of a Year One Report or a Supplemental

Report containing a recommendation that a response plan should be prepared and

implemented, Defendants shall contact the Division to initiate consultation regarding

development of a reasonable and appropriate response plan.

c. Termination of Monitoring Provisions. If upon completion of the thirty-six

(36) month term of the monitoring program and submission of the Supplemental Report, a

Response Plan is not required pursuant to Paragraph 16(a), Denver and IRG Bayaud shall

have no further obligation to monitor groundwater or surface water, to develop and

implement a Response Plan, or to perform any other work relating to the Site pursuant to

this Decree.


17

17. Response Plan. If a Response Plan is required pursuant to Paragraph 16(a), the

Parties agree to the following:

a. Timing for Response Plan. Within ninety (90) days after a Response Plan is

triggered or recommended, Denver and IRG Bayaud shall submit a Response Plan to the

Division that includes a detailed evaluation of response alternatives.

b. Response Alternatives. The scope of responses to be considered will include all

of the alternatives listed in the Exhibit D, and any other response that may be reasonable

and appropriate in light of the conditions, including further monitoring to better understand

trends, additional characterization of conditions or active remedial measures.

c. Response Plan Components. The “Response Plan” must be detailed and

identify: (i) the concern to be addressed by the response action; (ii) the proposed response

action and an explanation for why it should be selected; (iii) identification of alternative

responses that were considered, including those identified in Dr. Lipson’s March 7, 2016

report and any response action identified during the consultation with the Division, with an

explanation for why the proposed response was selected over alternative responses,

including an assessment of the relative effectiveness, implementability and cost of the

various response alternatives; and (iv) a timeline for implementation of the Response Plan.

d. Contractors. Denver and IRG Bayaud shall retain one or more contractors to

perform the Response Plan work and shall notify the Division of the name(s) and

qualifications of such contractor(s) within fourteen (14) days. Denver and IRG

Bayaud shall also notify the Division of the name(s) and qualifications of any other


18

contractor(s) or subcontractor(s) retained to perform the Response Plan work at least five

(5) days prior to commencement of such work.

e. Contractor Approval. The Division retains the right to disapprove, for good

cause, any or all of the contractors and/or subcontractors retained pursuant to the foregoing

paragraph. If the Division disapproves of a selected contractor, Denver and IRG

Bayaud shall retain a different contractor and shall notify the Division of that contractor’s

name and qualifications within five (5) days after the selection of the new contractor.

f. Response Plan Approval. The Division may either approve the Response Plan

proposed pursuant to this paragraph or, consistent with its statutory and regulatory

authority, require an alternative remedial option be implemented.

g. Retention of Right to Challenge. Denver and IRG Bayaud do not waive their

ability to challenge any action by the Division to compel a response action other than the

one proposed by Denver and IRG Bayaud. Such challenge shall be subject to the dispute

resolution provisions in Article XIV.

h. Timeline for Implementing a Response Plan. Denver and IRG Bayaud must

commence implementation of the Response Plan within ninety (90) days after notice of

Division approval of the plan.

i. Completion of Response Plan. The Response Plan will be completed, and no

further response or monitoring work will be required under this Decree, upon a written

notice from the Division that the Response Plan has been completed.


19

VI. WITHDRAWAL OF CLEANUP ORDER

18. Upon the entry of this Decree by the Court, the Division shall withdraw the

Cleanup Order, which thereupon shall have no further force and effect.

VII. STATE COURT PROCEEDINGS

19. Within seven (7) days after lodging of this Decree with the Court, IRG Bayaud

will notify the Colorado Court of Appeals that a settlement has been reached, that final dismissal

of the State Court Appeal is contingent upon termination of the Permit through a regulatory

process and entry of this Decree, and that either a motion to dismiss will be filed upon entry of

this Decree or the Colorado Court of Appeals will be notified that the settlement has terminated

without entry of the Decree and that briefing will begin.

20. No later than seven (7) days after the date of entry of this Decree, IRG Bayaud

shall dismiss the State Court Appeal, which the Division shall consent to, with IRG Bayaud and

the Division each to pay its own fees and costs in the state court proceeding.

VIII. THE DEPARTMENT’S CONTINUED AUTHORITY

21. The Division does not, by virtue of entering into this Decree, waive any authority

it has pursuant to state law, including but not limited to the authorities granted in C.R.S. §§ 25-8-

601 to 612.

22. Nothing in this Decree shall preclude the Department from imposing additional

requirements pursuant to its statutory authority in the event that additional information is

discovered that indicates such requirements are necessary to protect human health or the

environment.


20

23. Expert determinations set forth in the Year One Report and the Supplemental

Report will be a factor considered in determining whether and how the Division exercises any

authority described in this Article VIII.

IX. SUPPLEMENTAL ENVIRONMENTAL PROJECT

24. IRG Bayaud agrees to pay, within ninety (90) days after entry of this Decree, two-

hundred fifty thousand dollars ($250,000) to Denver as a supplemental environmental project

(“SEP Payment”). Denver will apply the SEP Payment toward a project having a total cost of at

least five-hundred thousand dollars ($500,000) and that provides water quality benefits to the

South Platte River. IRG Bayaud shall not deduct the SEP Payment for any tax purpose or

otherwise obtain any favorable tax treatment of such payment or project.

25. Denver shall undertake the project described in the SEP Proposal, attached hereto

as Exhibit E (the “Project”), which the Parties agree is intended to secure significant

environmental or public health protection and improvements.

26. IRG Bayaud and Denver certify that, as of the date of this Decree, neither is

required to perform or develop the Project by any federal, state or local law or regulation, and

neither is required to perform or develop the Project by any agreement, grant or any injunctive

relief in this or any other case. IRG Bayaud and Denver further certify that neither has received,

nor will receive, credit in any other enforcement action for the Project; and that they are not

otherwise required by law, and are unaware of any other person that is required by law, to

perform the Project. Denver further certifies that it will not claim credit for the SEP Payment as

compliance with its Municipal Separate Storm Sewer System permit.


21

27. Denver shall submit a SEP Completion Report to the Division by the date

specified in the SEP Proposal/Agreement Form. The SEP Completion Report shall contain the

following information:

a. A detailed description of the Project as implemented;

b. A description of any operating problems encountered and the solutions thereto;

c. Itemized costs, documented by copies of purchase orders and receipts or cancelled

checks;

d. Certification that the Project has been fully implemented pursuant to the

provisions of this Decree; and

e. A description of the environmental and public health benefits resulting from

implementation of the Project (with quantification of the benefits and pollutant reductions,

if feasible).

28. The Project must be completed to the satisfaction of the Division, within two (2)

years of the entry of this Decree.

X. FEES AND COSTS

29. Within sixty (60) days from entry of this Decree, the Defendants will pay an

agreed sum of five hundred sixty thousand dollars ($560,000) to Guardians to resolve Guardians’

claim for attorneys’ fees and costs in this case. Notice of the payment shall be provided to the

Division consistent with Article XI.

30. Counsel for Guardians shall provide wire transfer instructions to counsel for

Defendants at least ten (10) days prior to the date payments are due under this Decree.


22

XI. NOTICES

31. Any notifications under this Decree shall be directed to the individuals at the

addresses specified below by United States Mail or Overnight Courier and e-mail, unless these

individuals or their successors give notice of a change to the other Parties in writing:

As to Plaintiff WildEarth Guardians:

Jen Pelz, Wild Rivers Program Director WildEarth Guardians 2590 Walnut Street Denver, CO 80205 [email protected]

With a copy to: Sarah McMillan, Senior Staff Attorney WildEarth Guardians P.O. Box 7516 Missoula, MT 59807 [email protected]

As to the Division:

Kelly Morgan Unit Manager, Enforcement 4300 Cherry Creek Drive South Denver, CO 80246 [email protected]

As to Defendants IRG Bayaud, LLC and Brent Anderson:

Brent Anderson IRG Bayaud, LLC 7921 Southpark Plaza, Suite 109 Littleton, CO 80120 [email protected]

With a copy to:

Scott Clark, Esq. Burns, Figa & Will, P.C. 6400 S. Fiddler’s Green Cir., Suite 1000


23

Greenwood Village, CO 80111 [email protected]

As to Defendant City and County of Denver:

Executive Director, Department of Environmental Health or Designee 201 West Colfax Avenue, Dept. 310 Denver, Colorado 80202

With a copy of any such notice to:

Denver City Attorney’s Office 1437 Bannock St., Room 353 Denver, Colorado 80202

XII. LODGING AND ENTRY OF DECREE

32. The Parties agree to cooperate in good faith in order to obtain the Court’s review

and entry of this Decree.

33. Pursuant to 33 U.S.C. § 1365(c)(3), Guardians shall lodge this Decree with the

Court and shall simultaneously provide copies of this Decree to the United States Department of

Justice and the EPA (collectively, the “United States”) for review and comment for a period not

to exceed forty-five (45) days.

34. If the United States does not object or intervene within forty-five (45) days of

receipt, and upon termination of the Permit, and following the expiration and exhaustion of all

Parties’ rights to appeal the final termination of the Permit, the Parties shall submit a joint

motion to the Court requesting entry of this Decree. The motion for entry of this Decree shall be

filed no later than three (3) days following the completion of: 1) the final agency action

terminating the Permit, described in paragraph 8 of the Decree and 2) the United States’ forty-

five (45) day review period, described in paragraph 33 of the Decree.


24

XIII. EFFECT OF DECREE

35. Entry of this Decree shall:

a. Cause dismissal, with prejudice, of Guardian’s Second Amended Complaint and

of the Division’s complaint upon intervention;

b. Resolve and effect a complete release of any and all claims or potential claims of

Guardians against the Defendants that were or could have been asserted in the Second

Amended Complaint or relating in any way to the Site or the Permit; provided, however,

that Guardians reserves the right to enforce this Decree in the event of a breach by the

Defendants and to seek its fees and costs associated with such enforcement;

c. Resolve and effect a complete release of any and all claims or potential claims of

the Division against the Defendants that were or could have been asserted in this action, in

the Cleanup Order or in any other forum with respect to the Site or the Permit as of the date

of the lodging of this Decree in the Court; provided, however, that the Division reserves the

right to enforce this Decree in the event of a breach by the Defendants and retains the rights

reserved in Paragraphs 21 and 22; and

d. Shall be deemed to resolve and effect a complete release of IRG Bayaud’s claims

against the Division in the State Court Appeal.

36. Except as expressly stated in this Decree, the Defendants reserve all defenses and

all rights and remedies, legal and equitable, available to them in any action brought by Guardians

or the Division under this Decree, the Permit, the Cleanup Order or any federal or state statutes,

regulations or laws. This Decree shall not be construed as a waiver of any defenses or remedies


25

that Defendants may have to any future alleged violations of, or liability under, the Decree, the

Permit, the Cleanup Order or any federal or state statutes, regulations or laws.

37. This Decree does not limit or affect the rights of the Parties against any third party

not a party to this Decree.

38. This Decree shall not be construed to create rights in, or grant any cause of action

to, any third party not a party to this Decree.

39. The Parties do not admit any fact or liability arising out of the transactions or

occurrences alleged in the Second Amended Complaint, the State Appeal, the Cleanup Order or

otherwise.

40. This Decree, including Exhibits A, B, C, D and E, which are incorporated herein

by reference, constitutes the final, complete and exclusive agreement and understanding among

the Parties with respect to the settlement embodied in this Decree, and supersedes all prior

agreements and understandings among the Parties related to the subject matter herein. No

document, representation, inducement, agreement, understanding, or promise constitutes any part

of this Decree or the settlement it represents, nor shall they be used in construing the terms of

this Decree.

41. Material modifications to this Decree may be made only upon written agreement

of the Parties and approval of the Court. Non-material modifications to this Decree, including

changes to any schedule or deadline and the location and construction of any well, may be made

by written agreement of the Parties. Pursuant to 33 U.S.C. § 1365(c)(3), the United States shall

be provided with the opportunity to review and comment upon any proposed material

modification to this Decree. Any Party may in writing waive any provision of this Decree to the


26

extent such provision is for the benefit of the waiving Party. No action taken pursuant to this

Decree by any Party shall be deemed to constitute a waiver of any other Party’s compliance with

the provisions of this Decree.

42. This Decree shall take effect on the date it is entered by this Court.

XIV. DISPUTE RESOLUTION

43. Unless otherwise expressly provided for in this Decree, the dispute resolution

procedures of this Article shall be the exclusive mechanism to resolve disputes arising under or

with respect to this Decree. The failure of a Defendant to seek resolution of a dispute under this

Article shall preclude that Defendant from raising any such issue as a defense to an action by

Guardians or the Division to enforce any obligation of the Defendant arising under this Decree.

Defendants are obligated to continue all monitoring obligations pursuant to this Decree during

the informal and formal dispute resolution processes. If the subject of the dispute is the need for

a Response Plan, or the contents of the response plan or any alternative response option, then

Defendants’ obligations to prepare and implement a Response Plan or alternative remedial option

are stayed during the informal and formal dispute resolution processes.

44. Informal Dispute Resolution. Any dispute subject to Dispute Resolution under

this Decree shall first be the subject of informal negotiations. The dispute shall be considered to

have arisen when any Defendant sends Guardians and the Division a written Notice of Dispute.

Such Notice of Dispute shall state clearly the matter in dispute. The period of informal

negotiations shall not exceed twenty (20) days from the date the dispute arises, unless that period

is modified by written agreement. If the Parties cannot resolve a dispute by informal

negotiations, then the position advanced by the Division shall be considered binding unless,


27

within thirty (30) days after the conclusion of the informal negotiation period, any Defendant

invokes formal dispute resolution procedures as set forth below.

45. Formal Dispute Resolution. Any Defendant may invoke formal dispute

resolution procedures, within the time period provided in the preceding Paragraph, by serving on

the Division and Guardians a written Statement of Position regarding the matter in dispute. The

Statement of Position shall include, but need not be limited to, any factual data, analysis, or

opinion supporting the Defendant’s position and any supporting documentation relied upon by

the Defendant.

46. The Division shall serve its Statement of Position within forty-five (45) days of

receipt of the Defendant’s Statement of Position. The Division’s Statement of Position shall

include, but need not be limited to, any factual data, analysis, or opinion supporting that position

and any supporting documentation relied upon by the Division. The Division’s Statement of

Position shall be binding on the Defendant(s), unless the Defendant(s) files a motion for judicial

review of the dispute in accordance with the following paragraph.

47. Any Defendant(s) may seek judicial review of the dispute by filing with the

United States District Court for the District of Colorado and serving on the Division and

Guardians, in accordance with Article XI (Notices), a motion requesting judicial resolution of the

dispute. The motion must be filed within fourteen (14) days of receipt of the Division’s

Statement of Position pursuant to the preceding paragraph. The motion shall contain a written

statement of the Defendant(s) position on the matter in dispute, including any supporting factual

data, analysis, opinion, or documentation, and shall set forth the relief requested and any

schedule within which the dispute must be resolved for orderly implementation of the Decree.


28

48. The Division shall respond to the Defendant’s motion within the time period

allowed by the Local Rules of this Court. Guardians may also file a response to the Defendant’s

motion within the time period allowed by the Local Rules. The Defendant(s) may file a reply, to

the extent permitted by the Local Rules.

49. Standard of Review

a. Disputes Concerning Matters Accorded Record Review. Except as otherwise

provided in this Decree, in any dispute pertaining to the adequacy or appropriateness of

plans, procedures to implement plans, schedules or any other items requiring approval or a

determination by the Division under this Decree; the adequacy of the performance of work

undertaken pursuant to this Decree; and all other disputes that are accorded review on the

administrative record under applicable principles of administrative law, the Defendant(s)

shall have the burden of demonstrating, based on the administrative record, that the

position of the Division is arbitrary and capricious or otherwise not in accordance with law.

b. Other Disputes. Except as otherwise provided in this Decree, in any other

dispute, the Defendant(s) shall bear the burden of demonstrating that its position complies

with this Decree and furthers the objectives of the Decree.

50. Except as otherwise provided in Paragraph 43, the invocation of dispute

resolution procedures under this Article shall not, by itself, extend, postpone, or affect in any

way any obligation of the Defendants under this Decree, unless and until final resolution of the

dispute so provides.


29

XV. TERMINATION

51. This Decree shall be subject to termination on motion by any Party upon:

a. Termination of monitoring and Response Plan obligations pursuant to Paragraph

16.c., or, if a Response Plan is required pursuant to Paragraph 16.a., confirmation issued

pursuant to Paragraph 17.i. that the response plan has been completed;

b. Dismissal of the State Appeal pursuant to Article VII (State Court Proceedings);

c. Payment of IRG Bayaud’s SEP contribution and completion of the Project

pursuant to Article IX (Supplemental Environmental Project); and

d. Payment of Guardians’ attorneys’ fees and costs pursuant to Article X (Fees and

Costs).

52. At such time as any Defendant believes all such requirements have been fulfilled,

the Defendant shall so certify to the Division and Guardians. Not earlier than thirty (30) days

after such certification, any Party may apply to the Court for termination of the Decree. The

rights, releases and obligations set forth in Article XIII (Effect of Decree) shall survive

termination of the Decree as contractual obligations.

XVI. SIGNATURES

53. Each undersigned representative of the Parties certifies that he or she is fully

authorized to enter the terms and conditions of this Decree and to execute and legally bind such

Party to this document.

54. This Decree may be signed in counterparts.


of 4

Colorado Discharge Permit System (CDPS) Fact Sheet To Permit Number CO0046329

IRG BAYAUD, LLC, IRG BAYAUD DENVER WORKS, DENVER COUNTY

Erin Scott Public Notice Draft Date March 13, 2017

TABLE OF CONTENTS

I. TYPE OF PERMIT

II. FACILITY INFORMATION

III. RECEIVING STREAM

IV. FACILITY DESCRIPTION

V. FINAL EVALUATION

VI. REFERENCES

VII. PUBLIC NOTICE COMMENTS

I. TYPE OF PERMIT Individual

A. Permit Type: Termination B. Discharge To: Surface Water

II. FACILITY INFORMATION

B. Facility Location: 1271 West Bayaud Ave, Denver, CO 80223,

Latitude: 39.7148oW, Longitude: -105.00278o

III. RECEIVING STREAM A. Waterbody Identification: COSPUS14, South Platte River

IV. FACILITY DESCRIPTION

A. Industry Description IRG Bayaud, LLC (“IRG Bayaud”) was a former owner of real property located at 1271 W. Bayaud Avenue in Denver, Colorado, adjacent to the South Platte River (otherwise known as the General Chemical Corporation- Denver Works site


Exhibit A

Water Quality Control Division Fact Sheet, Permit No. «PERMIT_NUMBER»

Page 2 of 4

(“Site”). Beginning in 1986, General Chemical Corporation (GCC) owned and operated the Site, which consisted primarily of an aluminum sulfate (alum) manufacturing plant in the central portion of a 40-acre site. The Site was owned and operated by GCC until approximately 2008. Historic industrial operations at the Site caused low pH conditions and the deposition of heavy metals in soil and groundwater beneath the Site. Groundwater moves under and through the site, mobilizing arsenic and other pollutants and eventually emanating as a seep or seeps along the western bank of the South Platte River. In 2000, the Division first learned of water quality problems at the Site. A member of the public submitted a complaint after observing a milky white seep discharging from the river bank near the Site directly into the South Platte River. On October 9, 2000, the Denver Department of Environmental Health, Environmental Protection Division (“Denver EPD”) sent a letter to the Division outlining its concerns about the water quality problems observed at the Site, including that Site groundwater sampling established exceedances of state groundwater standards for pH and certain metals and that data collected in the South Platte River indicated the South Platte River was being impacted by a discharge (seep) downgradient of the General Chemical site. Based on this information, in 2006, the Division issued CDPS Permit CO0046329 to GCC (“Permit”). The Permit put forth effluent limitations for pH, and monitoring requirements for aluminum, cadmium, arsenic, copper, manganese, zinc, and acute whole effluent toxicity. The Permit was issued in conjunction with a submission of a draft plan to conduct Site clean-up under the provisions of Colorado’s Voluntary Cleanup and Redevelopment Act’s voluntary clean-up program (VCUP) implemented by the Department’s Hazardous Materials and Waste Management Division (“HMWMD”). In about 2008, IRG Bayaud acquired the site, dismantled the industrial infrastructure on the site, commenced implementation of a voluntary clean-up plan approved by HMWMD, and applied for transfer of the Permit from GCC to IRG Bayaud. In February 2008, after assuming operational control of the site, IRG submitted an application to transfer ownership of the Permit from GCC to IRG. The Permit was transferred to IRG Bayaud effective March 4, 2008.

B. Wastewater Treatment/ Source Control Description

Pursuant to the approved VCUP plan, IRG Bayaud excavated rock fill material from hot spots on the site, installed a low-permeability cap on the site and performed limited sodium hydroxide injections to further treat areas of low pH groundwater. This remedial approach aimed to remove rock fill material, alter the pH conditions in the groundwater and prevent the leaching of certain metals (specifically cadmium) into the groundwater. However, pursuant to the approved VCUP plan, IRG left the majority of the contaminated soils onsite. In 2010, following implementation of the approved VCUP plan, groundwater monitoring data gathered at the Site established that arsenic concentrations in two nested groundwater wells, screened in the medium and deep elevations of the saturated aquifer, were increasing. Historically, dissolved arsenic was not present in high levels in groundwater beneath the Site and was not a pollutant of concern identified in IRG’s VCUP remedy. In response to the change in Site conditions, staff from the HMWMD requested that IRG Bayaud conduct a Supplemental Groundwater Investigation to address increasing arsenic concentrations in the groundwater. IRG Bayaud submitted a Supplemental Groundwater Investigation Report (dated July 10, 2013 and revised January 30, 2014) that presented the results of additional soil and groundwater investigation and analysis conducted by Dr. Don Langmuir. According to that report:



Page 3 of 4

The arsenic that is currently increasing in the lower zones of the aquifer is a result of changes to the hydrogeochemistry caused by the CDPHE-approved remedy. Prior to the site cap, oxygenated acidic water entered the upper and lower flow zones of the hydrogeologic system. . . Subsequently, (after May 2009) the cap placed on the site cut off the oxygen supply in subsurface soil air and entering the system dissolved in meteoric waters. The lack of an oxygen supply combined with dissolved organic carbon entering the groundwater in recharge from the river and traces of organic matter in the subsurface soils have depleted the oxygen in the groundwater, creating reducing conditions in the middle and lower aquifers. These conditions have led to dissolution of the iron (III) oxides that had previously immobilized the arsenic, releasing the arsenic to groundwater and raising the pH . . . .

A visible milky-white discharge is no longer visible at the site of the historic seep because of the implementation of IRG’s VCUP remedy. However, overall groundwater migration patterns at the Site, including the overall flow pattern towards the South Platte River, do not appear to be significantly modified by the VCUP remedy. Water quality monitoring data provided to the Department by IRG to date provides inconclusive information about the ultimate fate of pollutants in groundwater. Therefore, through the Consent Decree referenced below, a comprehensive groundwater and surface water monitoring and reporting program has been established to continue to evaluate the changed site conditions that have occurred as a result of the VCUP remedy. This monitoring and reporting program goes above and beyond the scope of the monitoring required by the Permit.

V. FINAL EVALUATION TERMINATION Based on the foregoing, and the reasons set forth in the Consent Decree memorializing a settlement that has been reached in WildEarth Guardians, et al. v. IRG Bayaud, LLC, et al., U.S. District Court for the District of Colorado, Case No. 1:14-cv-01153-MSK-KLM, the department is terminating Permit No. CO0046329. The settlement establishes a comprehensive groundwater and surface water monitoring and reporting program to continue to evaluate the changed site conditions that have occurred as a result of the VCUP remedy. A Consent Decree memorializing the settlement is currently being filed with the United States District Court for the District of Colorado and can be obtained through court records.

VI. REFERENCES

A. Colorado Department of Public Health and Environment, Water Quality Control Division Files, for Permit Number CO0046329.

B. Basic Standards and Methodologies for Surface Water, Regulation No. 31, Colorado Department of Public Health and Environment, Water Quality Control Commission, effective June 30, 2016.



Page 4 of 4

C. Classifications and Numeric Standards for South Platte River Basin, Laramie River Basin, Republican River Basin, Smoky Hill River Basin, Regulation No. 38, Colorado Department of Public Health and Environment, Water Quality Control Commission, effective June 30, 2016.

D. Colorado Discharge Permit System Regulations, Regulation No. 61, Colorado Department of Public Health and

Environment, Water Quality Control Commission, effective June 30, 2015.

VII. PUBLIC NOTICE COMMENTS


SETTLEMENT DOCUMENT SUBJECT TO CRE 408 AND FRE 408

Hydro Science and Engineering, LLC · 15765 W. 63rd Ave. · Arvada, CO 80403

Page 1 of 9

October 27, 2016 Mr. Scott A. Clark, Esq. Attorney at Law Burns Figa & Will, P.C. 6400 S. Fiddler’s Green Circle Suite 1030 Englewood, CO 80111 Subject: Evaluation of Potential Arsenic Transport in Groundwater

Former General Chemical Company (GCC) Site 1271 West Bayaud Ave, Denver, Colorado In the Matter of: WildEarth Guardians v. IRG Bayaud LLC, Brent Anderson, and the City and County of Denver Case No: 14-cv-01153-MSK-KLM

Dear Mr. Clark: As requested I am providing this evaluation of the potential for arsenic to be transported in groundwater hydraulically downgradient from the Former General Chemical Site located at 1271 West Bayaud Ave, Denver, Colorado (site). The purpose of this evaluation is to estimate whether and to what extent elevated concentrations of arsenic detected in site groundwater samples are mobile and potentially migrating offsite, and whether and to what extent elevated arsenic concentrations in site groundwater samples may pose an imminent and substantial threat or any other kind of threat to the South Platte River. As discussed more fully below, the capacity of the alluvial aquifer beneath the site to assimilate arsenic via naturally-occurring sorption mechanisms is overwhelming compared to the amount of arsenic present in site groundwater. Accordingly, there is not an imminent or substantial threat that site-related arsenic could be transported off-site in groundwater and impact the South Platte River. Indeed, there is not even a minor threat that the river could be impacted even if all arsenic beneath the site cap were to dissolve into groundwater. Background The site underwent active remediation in 2009 in accordance with a CDPHE-approved Voluntary Cleanup Plan (VCUP; Parsons, 2007). Site remediation activities completed by IRG in 2009 included hot spot removal, regrading, and capping, and were documented in a CDPHE-approved construction completion report (CDPHE, 2009). Additional site remediation activities completed by the City and County of Denver during redevelopment of the site in 2009 included excavation of additional source material, capping, and soil amendments, and were documented in a CDPHE-approved construction completion report (City and County of Denver, 2011). As part of the approved VCUP, the site was issued an Environmental Covenant for protecting human health and the environment by restricting access to groundwater, providing maintenance of the remedy,

EXHIBIT B




10/27/2016 Page 2 of 9

and restricting future land use. Restrictions include, among other things, a prohibition on extracting groundwater at the site for any use; a prohibition on excavation, tampering, or disturbing site soil; and restricting future use of the site to commercial, industrial, and municipal uses. Arsenic was not emphasized as a chemical of concern (COC) during site remediation activities which occurred in 2009; rather, the main contaminants in groundwater at that time were low pH conditions and dissolved metals including cadmium, zinc, copper, aluminum, and manganese. This is because arsenic behaves differently than these metals in the environment. Prior to site remediation in 2009, site groundwater was oxidizing and arsenic does not readily dissolve under oxidizing conditions. After the site remediation activities were completed in 2009, site groundwater became more reducing because oxygenated rainfall and snowmelt could no longer infiltrate the waste rock, and arsenic began to dissolve into groundwater via reductive dissolution. Arsenic concentrations in groundwater samples collected at monitoring wells MW-19M and MW-19D began to increase during effectiveness monitoring activities. However, arsenic concentrations in groundwater samples collected at monitoring wells MW-19M and MW-19D have shown a decreasing trend since early 2013. Arsenic concentrations in groundwater samples collected at monitoring wells MW-7R and MW-7SR have shown a decreasing trend since late 2009. Since remediation was completed in 2009, arsenic has been detected at levels above the voluntary cleanup (VCUP) standard in groundwater samples collected at site monitoring wells MW-7R, MW-7RS, MW-19M and MW-19D. Arsenic levels detected in samples collected at these wells are summarized as follows:

Summary of Residual Arsenic Levels Detected in Groundwater Samples (ug/L)

MW-7R (n=34)

MW-7SR (n=33)

MW-19M (n=50)

MW-19D (n=87)

Timeframe 2001 – 2016 2007 – 2016 2007 – 2016 2008 – 2016 Minimum 14 8 2 3 Maximum 134 37 32 319 Average 102 27 19 171 Median 108 28 20 189

Most Recent 101* 24* 20** 280** * September 2016. ** October 2016 ug/L = micrograms per liter.

Physical Evidence Demonstrating Natural Attenuation of Arsenic in Site Groundwater Groundwater samples have been collected routinely at site monitoring wells since 2009 and surface water samples have been collected near the site since around 2001, including monthly for the past two years (Figures 1 and 2). These groundwater and surface water samples can be used to empirically evaluate the potential for site-related arsenic to be transported in groundwater and hypothetically impact the South Platte River. Over 170 surface water samples have been collected in the South Platte River at designated sampling locations upstream and downstream of the site, and adjacent to the location of the former “milky white

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seep.” The South Platte River surface water sampling locations are shown on Figure 1 and are designated as N1, N4A, N4B, and N7. None of the surface water samples collected in the South Platte River at stations N1, N4A, N4B, and N7 either before, during, or after site remediation activities has demonstrated any evidence that site-related arsenic has migrated toward or impacted the river. As a matter of fact, the South Platte River surface water samples that have been collected at stations N1, N4A, N4B, and N7 indicate that there is a regional arsenic problem in the river that originates upstream from the site. These data further demonstrate that the river is a source of arsenic to the site, because the river loses water to and recharges the alluvial aquifer at the site. In other words, river water with arsenic in it flows into the alluvial aquifer under the site. Additionally, 34 groundwater samples have been collected at site monitoring well OFF-4 which is located along the downgradient perimeter of the site and is directly downgradient from the MW-19 well cluster (Figure 2). As discussed above, groundwater samples collected at the MW-19 well cluster have elevated arsenic concentrations. Therefore, if elevated arsenic concentrations were hypothetically being transported in groundwater away from the MW-19 location, they would be detected at the OFF-4 location. The OFF-4 groundwater data show arsenic levels that vary between 1.6 and 8.9 ug/L and average 3.8 ug/L, well below the VCUP standard. This result shows that the zone of arsenic in site groundwater with levels above the VCUP standard is not expanding, and that arsenic is not being transported off-site in groundwater. The reason that the zone of arsenic in site groundwater at levels above the VCUP standard is stable and not expanding is due to naturally-occurring geochemical reactions in the alluvial aquifer that immobilize arsenic. The two main naturally-occurring geochemical reactions that are known to attenuate arsenic in groundwater are (1) sorption; and (2) mineral precipitation. The state of the science, knowledge, and practice regarding the role that these reactions play in immobilizing arsenic in groundwater and preventing arsenic migration are not new, and have evolved over several decades to the point that use of monitored natural attenuation (MNA) has been approved as an acceptable remedy for arsenic in groundwater at many sites (e.g., Reisinger et al, 2005). Evaluation of Potential Arsenic Transport in Groundwater Approach The evaluation is focused on attenuation of arsenic in groundwater by means of sorption of dissolved arsenic onto iron-oxide minerals naturally present in the alluvial aquifer, and is premised on decades of scientific research which demonstrate unequivocally that arsenic can be readily sorbed onto iron-oxide minerals during transport. The net effect of the arsenic sorption mechanism is to slow down, or retard, the rate of arsenic migration relative to the rate of groundwater flow. The extent and intensity to which this sorption mechanism occurs depends on the amount (i.e., mass) of iron-oxide minerals present relative to the amount of arsenic. Therefore, a key component of the evaluation included estimating the mass of iron-oxide minerals and arsenic present in the subsurface beneath the site. The evaluation consisted of a series of calculations using standard hydrogeologic and environmental engineering methods aimed at quantifying the amount of arsenic present at the site and the potential rate of arsenic migration in groundwater. The evaluation approach generally followed these steps:

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• Identify conceptual framework;

• Estimate parameters using site-specific data wherever possible;

• Calculate mass of arsenic present in groundwater beneath the site cap (i.e., amount of arsenic contained in one pore volume of groundwater);

• Calculate the mass of arsenic present in saturated soils beneath the site cap (i.e., amount of

arsenic in soil below the water table); • Calculate the potential flux of groundwater leaving the site using Darcy’s Law;

• Calculate the potential mass flux of arsenic leaving the site by groundwater transport (i.e.,

groundwater flux times arsenic concentration); • Calculate the mass of iron-oxide minerals present in the alluvial aquifer (i.e., sorption capacity);

and • Calculate the potential rate of arsenic advancement under a series of hypothetical scenarios.

The calculations were performed in a Microsoft Excel® spreadsheet. A copy of the calculation spreadsheet is provided as Table 1. Supporting Data An extensive amount of environmental and groundwater monitoring data has been collected at the site during site characterization and remediation activities. These data include, among other things, water level measurements at monitoring wells and in the South Platte River; and collection of groundwater, surface water, and soil samples for laboratory analysis of COCs and other chemical parameters. Additionally, IRG and Dr. Donald Langmuir completed a geochemical investigation at the site focused on evaluating the mobility and transport of arsenic and other inorganic constituents in groundwater (IRG, 2014). The geochemical investigation involved completing six soil borings at the site with collection of soil and groundwater samples for specialized geochemical analyses. Key findings of the site geochemical investigation included:

• Average concentration of arsenic dissolved in groundwater beneath the site cap is approximately 88 ug/L;

• Average concentration of arsenic in saturated site soils beneath the site cap is approximately 65 mg/kg;

• Iron-oxide bearing minerals hematite, magnetite, and goethite are prevalent throughout the alluvial aquifer, at a concentration of approximately 2.5% by mass;

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• Reducing geochemical conditions are present in the alluvial aquifer beneath the site cap, and are the cause of elevated arsenic concentrations in some site groundwater samples; and,

• Oxidizing geochemical conditions are present in the alluvial aquifer downgradient from the site cap, which explains why arsenic concentrations are not elevated in groundwater samples at the OFF-4 monitoring well location.

Conceptual Framework The conceptual framework is a simplified form of reality, and its purpose is to serve as a basis for performing calculations. Simplifications include: rectangular geometry, assumption of homogeneous and isotropic material properties, assumption of linear quantitative relationships (e.g., Darcy’s Law), assumption of steady-state fluxes, and use of average parameter values. In reality, the geometry, hydrodynamics, and geochemistry of the alluvial aquifer beneath the site can be quite complex, nonlinear and transient, and the full complexity of the system cannot be fully accounted for in this type of evaluation. Therefore, simplifying assumptions are needed and parameter values were selected to be conservative from a risk perspective. The conceptual framework for this evaluation is shown in Figure 3. Key elements of the conceptual framework include:

• The alluvial aquifer beneath the cap is assumed to be in the shape of a rectangle, approximately 2,300 feet long, 350 feet wide, and 18 feet of saturated thickness.

• Groundwater flow is uniform and at steady state (i.e., does not vary over time).

• As dissolved arsenic migrates downgradient in groundwater, it sorbs to iron-oxide containing minerals.

• The rate of arsenic sorption onto iron-oxide containing minerals is faster than the rate of groundwater migration (i.e., there are no kinetic limitations).

• Iron-oxide containing minerals sorb dissolved arsenic up to their full sorption capacity (i.e., iron-oxide minerals can sorb up to 1% arsenic by mass) (IRG, 2014).

• Some of the arsenic sorption capacity of the iron-oxide minerals is already consumed by pre-existing conditions in which arsenic or other elements bind some of the sorption sites;

• Once the sorption capacity of the iron-oxide minerals is full of new and pre-existing arsenic, the iron-oxide minerals are said to be “passivated” and can no longer sorb additional arsenic. As the arsenic advances and consumes arsenic-sorbing capacity, a “passivated sorption zone” develops in which no further sorption occurs and arsenic is present as a dissolved phase. The passivated sorption zone therefore represents a zone into which dissolved arsenic has migrated and can no longer be sorbed. The rate at which the passivated sorption zone increases is equal to the rate of arsenic advancement, and is governed by the mass ratio between arsenic and iron-oxide minerals.

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Calculation Results Calculations and results are shown on Table 1 and summarized in the following subsections. 1. Arsenic Mass On Site Approximately 24 pounds of dissolved arsenic are estimated to exist in groundwater beneath the site cap, based on an average arsenic concentration in site groundwater samples of 88 ug/L. Approximately 153,000 pounds of arsenic are present as solids (i.e., in minerals) in saturated soil beneath the site cap, based on an average arsenic concentration in saturated site soil samples of 65 mg/kg. These results show that the vast majority of arsenic beneath the site cap is immobile because it exists in solid mineral grains (i.e., gravel, sand, silt, and clay) that are physically unable to migrate in the alluvial aquifer, and only a minor fraction of arsenic beneath the site cap (i.e., less than 0.1%) is potentially mobile in groundwater because it exists in the dissolved phase. These quantities were used in subsequent calculations to evaluate potential arsenic mobility. 2. Aquifer Arsenic Sorption Capacity (Unit Basis) The data show that each cubic foot of aquifer material weighs approximately 163 pounds and contains approximately 4 pounds of iron-oxide bearing minerals, which can sorb a maximum of 0.04 lbs of arsenic. This equates to a maximum arsenic sorption capacity of 230 milligrams arsenic sorbed per kilogram of soil (i.e., the maximum sorbed arsenic concentration is 230 mg/kg). Given that the average arsenic concentration of saturated site soil samples is 65 mg/kg, the results show that saturated soils beneath the site cap are not fully saturated with arsenic and have a significant capacity to sorb additional arsenic. 3. Aquifer Arsenic Sorption Capacity (Site-Wide Basis) Calculations show that greater than 1,000,000 tons of saturated aquifer material (i.e., soil) exist beneath the site cap, and that these saturated aquifer materials contain approximately 27,000 tons of iron-oxide bearing minerals. Given that there is up to 24 pounds of dissolved arsenic in groundwater beneath the cap, there is over 2,000,000 times more iron-oxide minerals in the aquifer beneath the site cap than dissolved arsenic in groundwater. The results further show that saturated soils beneath the site cap have a significant capacity to sorb additional arsenic. 4. Arsenic Mass Discharge Potentially Leaving the Site via Groundwater Transport It is estimated that approximately 0.02 pounds of arsenic may potentially be transported off-site per day via advective groundwater flow. This value was arrived at by first calculating the groundwater discharge rate using Darcy’s Law. The groundwater discharge rate in this case represents the amount of groundwater leaving the site at the downgradient border, which works out to approximately 3,780 cubic feet per day (ft3/day). This value was then multiplied by the average arsenic concentration in site groundwater samples (88 ug/L) to arrive at the potential arsenic mass discharge rate. This rate was used in subsequent calculations to evaluate the potential arsenic migration rate.

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5. Potential Arsenic Migration Rate – Average Conditions The rate of arsenic migration in groundwater is governed by the arsenic mass discharge rate in groundwater (0.02 lbs arsenic per day), the sorption capacity of the aquifer materials (0.04 lbs of arsenic per cubic foot of aquifer material), and the dissolved arsenic concentration (average of 88 ug/L). Under average groundwater flow and geochemical conditions at the site, it is estimated that the potential arsenic migration rate is on the order of 0.30 millimeters per year. The rationale for this calculation is as follows: 0.02 pounds of arsenic will fully occupy the remaining sorption capacity of 2.8 pounds of iron-oxide minerals if 25% of the sorption capacity is already occupied due to pre-existing conditions. 2.8 pounds of iron-oxide minerals take up approximately 0.02 cubic feet of space assuming the iron-oxide minerals have a density of 163 pounds per cubic foot. 0.02 cubic feet of space, distributed over a cross-sectional area of flow of 6,300 square feet (350 feet wide by 18 feet thick) gives a distance along the direction of flow of 0.000003 feet, which means that arsenic advances approximately 0.000003 feet per day as the sorption capacity of the aquifer materials is slowly consumed. This rate equates to 0.30 millimeters per year. 6. Potential Arsenic Migration Rates – Elevated Arsenic Concentrations in Groundwater Following the same procedure as above, potential arsenic migration rates under elevated arsenic concentrations in groundwater were calculated as follows:

Arsenic Concentration in Groundwater (ug/L) Potential Arsenic Migration Rate (mm/year)

88 (average) 0.30

100 0.34

200 0.68

500 1.71

7. Potential Maximum Distance of Arsenic Migration – All Arsenic Assumed Mobile In the highly unlikely event that all the arsenic present beneath the site cap in both the solid and dissolved phases were to become potentially mobile and migrate offsite, it is estimated that the potential maximum distance of arsenic migration off site would be on the order of 20 feet. This estimate is considered conservative because: (1) the calculation accounts for all arsenic under the site cap, including naturally occurring and background arsenic; (2) the calculation assumes all the arsenic currently present under the site cap migrates off-site, whereas there will always be some arsenic sorbed to iron-oxide minerals in the alluvial aquifer materials; and (3) the calculation assumes the potential to dissolve arsenic is homogeneous in the alluvial aquifer (i.e., arsenic dissolution does not vary from location to location).

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Summary In conducting this evaluation, I reviewed extensive groundwater data collected at the site monitoring well network and surface water quality data collected in the South Platte River upstream and downstream of the site and adjacent to the location of the former milky white seep. Based on this review, the data empirically demonstrate that the zone of elevated arsenic concentrations in groundwater under the site cap is stable and not expanding. Using the site monitoring data and conservative assumptions, I calculated the potential rate and distance of arsenic migration in groundwater downgradient from the site to help explain why dissolved arsenic is not migrating in site groundwater and to provide a basis for evaluating potential future threats to the river. Based on the site data and calculations, it can be concluded that arsenic mobility in site groundwater is severely limited because there is very little dissolved arsenic compared to the overwhelming abundance of naturally-occurring iron-oxide minerals present in the alluvial aquifer that sorb arsenic and prevent it from migrating downgradient. Consequently, there is no discharge of arsenic from the site to the South Platte River via groundwater transport because the arsenic has been immobilized due to naturally-occurring geochemical reactions in the alluvial aquifer. Additionally, it is highly unlikely that there ever will be a discharge of site-related arsenic to the river because there is not enough arsenic mass under the site cap to migrate more than 20 feet from the property boundary. These results were arrived at using standard methods in the hydrogeology and environmental engineering practices and are within a reasonable degree of scientific certainty. Thank you very much for the opportunity to be of service. If you should have any questions or require additional information, please contact me. Very truly yours, HYDRO SCIENCE AND ENGINEERING LLC

David S. Lipson, Ph.D., C.P.G. President and Technical Expert References CDPHE. 2009. Construction Completion Report No Action Determination, General Chemical 1271 W. Bayaud Ave, Denver, CO. May 27, 20009. City and County of Denver (CCD). 2011. Construction Completion Report for City and County of Denver Development Activities. Denver Central Platte Campus / Former General Chemical Site. 1271 and 1241 West Bayaud Avenue, Denver, Colorado.

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IRG Bayaud, LLC and Hydrochem Systems Corporation (IRG). 2014. Supplemental Investigation of Arsenic in Groundwater at the Former General Chemical Site Central Platte Campus, City and County of Denver, Denver, Colorado. Prepared for CDPHE. HMWMD-RP-B2. 4300 Cherry Creek Drive South, Denver CO. Parsons. 2007. General Chemical Corporation Final Voluntary Cleanup Program Application Amendment, Revision 5. Reisinger, H.J., D.R. Burris, and J.G. Hering. 2005. Remediating Subsurface Arsenic Contamination with Monitored Natural Attenuation. Environ. Sci. & Technol. Vol 39(22): pp. 458A-464A.

EXHIBIT B


Input Parameters

Length of Cap 2,300 ft CCD, 2011.

Width of Cap 350 ft CCD, 2011.

Thickness of Saturated Zone Beneath Cap 18 ft Parsons, 2007.

Soil Density 163 lbs/ft3 Assumed.

Soil Porosity 0.3 Assumed.

Hydraulic Conductivity of Saturated Soil 200 ft/day Assumed.

Hydraulic Gradient across Site 0.003 Parsons, 2007.

Average Arsenic Concentration in Groundwater 88 ug/L IRG, 2014.

Average Arsenic Concentration in Soil Below Water Table 65 mg/kg IRG, 2014.

Iron Oxide Minerals in Saturated Soil Below Water Table 2.3% wt/wt IRG, 2014.

Arsenic / Iron Sorption Full Capacity 1.0% wt/wt IRG, 2014.

Amount of Iron Sorption Capacity Already Consumed 25% wt/wt IRG, 2014.

Calculations

Site Area 805,000 ft2

Cross Sectional Area of Flow 6,300 ft2

Saturated Soil Volume 1.4E+07 ft3

Pore Volume 4.3E+06 ft3 3.3E+07 gallons

Soil Mass 2.4E+09 lbs 1,177,313 tons

Arsenic / Iron Sorption Effective Capacity 0.75% wt/wt

1 Arsenic Mass On Site

Total As in GW 24 lbs

Total As in Soil 153,051 lbs

Total As under cap 153,075 lbs

2 Aquifer Arsenic Sorption Capacity (Unit Basis)

Soil Mass 163 lbs/ft3

Iron oxide mineral mass 3.7 lbs/ft3

Max mass of arsenic sorbed 0.04 lbs/ft3

Max arsenic concentration sorbed 230 mg/kg /ft3

3 Aquifer Arsenic Sorption Capacity (Site‐Wide Basis)

Total As in GW 23.9 lbs

Iron oxide minerals available to adsorb As 54,156,375 lbs 27,078 tons

Iron/Dissolved Arsenic Mass Ratio 2,267,765 <‐ Times more iron than dissolved arsenic on site

4 Arsenic Mass Discharge Potentially Leaving the Site

Groundwater discharge rate 3,780 ft3/day

As mass discharge rate 0.02 lbs As/day

5, 6 Potential Arsenic Migration Rate

Mass of iron consumed per day 2.8 lbs Fe consumed / day

Volume of iron consumed per day 0.02 ft3 Fe consumed / day

As migration rate 2.7E‐06 ft/day

0.8 um/day

0.30 mm/yr

7 Potential Max Distance of Arsenic Migration ‐ All Arsenic Assumed Mobile

Total As at the Site (Solids + Dissolved) 153,075 lbs As total

Total mass of iron consumed 20,409,934 lbs Fe consumed

Total volume of iron consumed 125,600 ft3 iron consumed by As

Distance of downgradient As migration 20 feet

Table 1

Arsenic Mobility Calculations

Former General Chemical Company Site

1271 West Bayaud Ave, Denver, Colorado

SETTLEMENT DOCUMENTSUBJECT TO CRE 408 and FRE

Arsenic Mobility Calculations Page 1 of 1 10/27/2016EXHIBIT B


Surface Water Sampling Locations

1FIGURE

Site

Surface Water Sampling Location

Monitoring Well MW‐19 Cluster

Wildearth Guardians v. IRG Bayaud, LLC et al.Civil Action No. 14‐cv‐01153‐MSK‐KLM

Hydro Science and EngineeringAll Locations are Approximate

N7

N4B

N4A

N1

Alameda Ave

1,000 Ft

Settlement DocumentSubject to CRE 408 and FRE 408

MW‐19

EXHIBIT B


Site Map Showing Monitoring Well Locations and Hydraulic Gradient – Sept 2016

2FIGURE


Hydro Science and Engineering

Source of Map:


EXHIBIT B


Arsenic Transport EvaluationDefinition Sketch

3FIGURE


Hydro Science and Engineering

Length of Passivated Sorption Zone

GW Flow

Site Cap Saturated Zone Downgradient of the Site Cap

Saturated Zone with As in GW Passivated Sorption Zone

Saturated Thickness

Cross Sectional Area of Flow


EXHIBIT B


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EXHIBIT C


CONFIDENTIAL SETTLEMENT DOCUMENT SUBJECT TO CRE 408 AND FRE 408


Page 1 of 5

March 7, 2016 Mr. Scott A. Clark, Esq. Attorney at Law Burns Figa & Will, P.C. 6400 S. Fiddler’s Green Circle Suite 1030 Englewood, CO 80111 Subject: Evaluation of Potential Arsenic Remedial Options in Groundwater

Former General Chemical Site In the Matter of: WildEarth Guardians v. IRG Bayaud LLC, Brent Anderson, and the City and County of Denver Case No: 14-cv-01153-MSK-KLM

Dear Mr. Clark: As requested I am providing this evaluation of potential remedial options for arsenic in groundwater at the Former General Chemical Site located at 1271 West Bayaud Ave, Denver, Colorado (site). Arsenic has recently been detected at levels above the voluntary cleanup (VCUP) standard in groundwater samples collected at site monitoring wells MW-19M and MW-19D. Arsenic levels detected in samples collected at these wells are summarized as follows:

Summary of Residual Arsenic Levels Detected in Groundwater Samples (ug/L) MW-19M

(n=36) MW-19D

(n=72) Minimum 2 3 Maximum 32 319 Average 19 152 Median 22 152

Date range: April 2001 through Sept 2015.

Background Site Remediation (2009) The site underwent active remediation in 2009 in accordance with a CDPHE-approved Voluntary Cleanup Plan (VCUP; Parsons, 2007). Site remediation activities completed by IRG in 2009 included hot spot removal, regrading, and capping, and were documented in a CDPHE-approved construction completion report (CDPHE, 2009). Additional site remediation activities completed by the City and County of Denver during redevelopment of the site in 2009 included excavation of additional source material, capping, and soil amendments, and were documented in a CDPHE-approved construction completion report (City and County of Denver, 2011).

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The site remediation activities are summarized as follows:

Remediation Activity Completed in 2009 Material Quantity Bevill Material Removed 9,518 CY Asbestos-Containing Bevill Material Removed 1,287 CY Petroleum Soil with Bevill Material Removed 1,054 CY Petroleum Soil with Asbestos and Bevill Material Removed 51 CY Concentrated Bevill Material Removed (chromium solids) 14 CY Bevill Material Removed during Redevelopment 27,764 CY

Total Source Material Excavated (max depth 20’ bg) 39,688 CY Hazardous Materials Removed (corrosive liquids/toxic solids) 6 containers One-Foot Thick Cap 30 acres Lime Placed in Foundation Excavations during Redevelopment 399 tons Contaminated Groundwater Removed 290,000 gallons

As part of the approved VCUP, the site was issued an Environmental Covenant for the purpose of protecting human health and the environment by restricting access to groundwater, providing maintenance of the remedy, and restricting future land use. Restrictions include, among other things, a prohibition on extracting groundwater at the site for any use; a prohibition on excavation, tampering, or disturbing site soil; and restricting future use of the site to commercial, industrial, and municipal uses. Groundwater and Surface Water Monitoring (2009 – Present) Groundwater and surface water monitoring samples have been collected quarterly at the site since remediation was completed. Arsenic concentrations in groundwater samples collected at monitoring well OFF-4 are shown on the attached Figure. The OFF-4 groundwater monitoring location is important because it is directly downgradient from the MW-19 well cluster. The OFF-4 groundwater data show that arsenic levels there are stable at a level around 3.5 ug/L, which is well below the VCUP standard. This result shows that the zone of arsenic in site groundwater with levels above the VCUP standard is not expanding. Recent data from the MW-19 well cluster suggest the zone of arsenic above standards has begun to shrink (i.e., attenuate). The reason that the zone of arsenic in groundwater at the site with levels above the VCUP standard is stable and not expanding is due to naturally-occurring geochemical reactions in the alluvial aquifer that immobilize arsenic. Dissolved arsenic readily sorbs to iron minerals that are abundant throughout the alluvial aquifer. The site geochemical investigation completed by Dr. Langmuir and IRG in 2014 collected site-specific, empirical data that demonstrated geochemical conditions in the alluvial aquifer are conducive to arsenic sorption and result in natural immobilization. In the remedial evaluation below, the terms “natural attenuation” and “natural immobilization” of arsenic are used interchangeably.

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Remedial Evaluation Methods of the remedial evaluation were in general accordance with procedures for conducting feasibility studies used by the United States Environmental Protection Agency (e.g., USEPA, 1988) and included assembling and screening a slate of potential remedial options for arsenic in groundwater at the site (Table 1). These remedial options were assembled based on historical remedial evaluations performed at the site, information provided by the USEPA, and knowledge and experience regarding groundwater remediation. The remedial options were then screened to evaluate the feasibility of each option based on five criteria: (1) short-term effectiveness; (2) long-term effectiveness; (3) implementability; (4) cost; and (5) degree of improvement or benefit to the South Platte River. Information regarding effectiveness, implementability, and cost of each remedial option was obtained from knowledge and experience regarding groundwater remediation, supplemented with additional information from USEPA’s Contaminated Site Clean-Up Information (CLU-IN) web site (i.e., www.clu-in.org). Potential remedial options for arsenic in groundwater must take into account site-specific features, and are limited due to the following site characteristics:

• Proximity to South Platte River; • Proximity to above-ground land use and infrastructure, including buildings, structures, parking

lots, utilities, fences, railroad tracks, and other above-ground features; • Proximity to subsurface infrastructure including sewer lines, water lines, and gas lines; • Heterogeneity of the alluvial aquifer; and • Complex geochemistry in the alluvial aquifer.

The evaluation of the potential remedial options is provided in Table 1. As shown, most remedial options were found to be infeasible due to lack of effectiveness, challenging or extremely challenging implementability due to site-specific constraints, or very high cost. Furthermore, because arsenic in groundwater at the site is immobile due to natural geochemical constraints and does not discharge into the South Platte River, it was determined that none of the potential remedial options will provide a tangible improvement or benefit to the river. For example, pumping and treating groundwater was found to be infeasible for the site because it will require pumping very large and wasteful quantities of clean water, it will be extremely challenging to implement, and it will have to be operated and maintained in perpetuity for very high cost. Moreover, pumping and treating arsenic-containing groundwater at the site will provide no tangible improvement or benefit at the South Platte River. Remedial options for physical containment via a sheet pile wall or permeable reactive barrier (PRB) were found to be infeasible because they will not be effective in the long term, they will be extremely challenging to implement due to the presence of buried subsurface infrastructure at the site, and they have very high costs. And, similar to pump and treat, neither of these remedial options will provide tangible improvements or benefits to the South Platte River.

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In-situ remedial options such as air sparging, aquifer sterilization, or in-situ chemical oxidation were found to be infeasible because these options are only temporarily effective, they are challenging to implement, and they would need to be operated and maintained in perpetuity at very high cost. And, similar to the above, in-situ groundwater remediation at the site will provide no tangible improvements or benefits to the South Platte River. The only remedial options that were found to be feasible for arsenic in groundwater at the site are institutional controls and natural attenuation. The existing prohibition on using groundwater at and near the site is an institutional control that prevents humans from directly contacting arsenic through ingestion of groundwater and is therefore highly effective. Natural attenuation of arsenic in groundwater at the site occurs due to naturally occurring geochemical reactions that effectively immobilize the arsenic and prevent it from migrating down-gradient of the site to the South Platte River. An extensive amount of geochemical data and routine groundwater monitoring data have already been collected at the site which demonstrate: (1) the presence of geochemical conditions necessary to immobilize the arsenic; and (2) low, stable concentrations of arsenic in groundwater samples from sentinel well OFF-4. These data show that arsenic in site groundwater has stabilized and is immobile, and that natural attenuation of arsenic in site groundwater is feasible as a remedial option. In conclusion, there is no discharge of arsenic from the site to the South Platte River via groundwater transport because the arsenic has been immobilized due to naturally-occurring geochemical reactions in the alluvial aquifer. Because of this lack of discharge, no amount of groundwater remediation at the site will result in tangible improvements or benefits in the South Platte River. Moreover, none of the active remedial options for arsenic are feasible at the site due to lack of effectiveness, challenges with implementation, and very high costs. Thank you very much for the opportunity to be of service. If you should have any questions or require additional information please contact me. Very truly yours, HYDRO SCIENCE AND ENGINEERING LLC

David S. Lipson, Ph.D., C.P.G. President and Technical Expert

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References CDPHE. 2009. Construction Completion Report No Action Determination, General Chemical 1271 W. Bayaud Ave, Denver, CO. May 27, 20009. City and County of Denver. 2011. Construction Completion Report for City and County of Denver Development Activities. Denver Central Platte Campus / Former General Chemical Site. 1271 and 1241 West Bayaud Avenue, Denver, Colorado. Parsons. 2007. General Chemical Corporation Final Voluntary Cleanup Program Application Amendment, Revision 5. USEPA. 1988. Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA. Office of Emergency and Remedial Response. EPA/540/G-89/004. OSWER Directive 9355.3-01.

EXHIBIT D


Arsenic

Res

ult

Non

dete

ctF

igu

re 7

.G

roun

dwat

er S

ampl

ing

Res

ults

for A

rsen

ic O

ver T

ime

05

10

15

20

25

30

35

40

45

50 Jan‐07

Jan‐09

Jan‐11

Jan‐13

Jan‐15

As (g/L)

MW‐19S

3 points out of range:

4/18/08 737 µg/L

5/15/08 660 µg/L

7/12/12 271 µg/L

05

10

15

20

25

30

35

40

45

50 Jan‐07

Jan‐09

Jan‐11

Jan‐13

Jan‐15

As (g/L)

MW‐19M

1 point out of range:

5/1/08 2,100 µg/L

0

50

100

150

200

250

300

350

400 Jan‐07

Jan‐09

Jan‐11

Jan‐13

Jan‐15

As (g/L)

MW‐19D

1 point out of range:

5/1/08 1,100 µg/L

012345 Jan‐07

Jan‐09

Jan‐11

Jan‐13

Jan‐15

As (g/L)

OFF‐4

EX

HIB

IT C

EXHIBIT D


Table 1

Evalua

tion of Arsen

ic Rem

edial O

ptions

Form

er Gen

eral Che

mical Site

Groun

dwater Gen

eral

Respon

se Action

Remed

ial Techn

ology

Process O

ption

Effectiven

ess

Implem

entability

Cost

Improvem

ent /

Ben

efit to th

e River

Feasiblity

No Furthe

r Action

All previou

s techn

ologies u

sed

at th

e site plus natural

attenu

ation.

Natural atten

uatio

nEffectiven

ess h

as been de

mon

strated. Historical quarterly

mon

itorin

g data over m

ore than

two years sho

w stabilizatio

n of pH and arsenic in groun

dwater.

Readily im

plem

entable.

Low, due

to adm

inistrativ

e and

consultin

g fees. ~ $1

0kThere is no

current disc

harge and

no fu

ture th

reat, so there is no

im

pact to

the riv

er.

Feasible.

Institu

tional Con

trols

State proh

ibition

on use of

grou

ndwater

City water su

pply

Effective over sh

ort a

nd long

term

. Prevents d

irect con

tact

through ingestion of groun

dwater.

Already im

plem

ented.

Low, due

to adm

inistrativ

e and

consultin

g fees. ~ $1

0kNo additio

nal ben

efit to th

e riv

er.

Feasible. A

lready

complete.

Site Enviro

nmen

tal Coven

ent

Land

Use Restrictio

nsEffective over sh

ort a

nd long

term

. Prevents d

irect con

tact

with

groun

dwater and

soil. Lim

its poten

tial leaching.

Already im

plem

ented.

Low, due

to adm

inistrativ

e and

consultin

g fees. ~ $1

0kNo additio

nal ben

efit to th

e riv

er.

Feasible. A

lready

complete.

Mon

itorin

gCo

ntinue

mon

itorin

gNatural atten

uatio

nFuture m

onito

ring even

ts wou

ld con

tinue

to validate

effectiven

ess o

f natural atten

uatio

n.Re

adily im

plem

entable.

Low, but highe

r than NFA

due

to

need

for field work and labo

ratory

analysis. ~ $50

k/yr

No additio

nal ben

efit to th

e riv

er.

Feasible.

Extractio

n and Treatm

ent

Groun

dwater collection wells

Vario

us treatm

ent o

ptions

(disc

harge to POTW

, ion

exchange…)

Effective for h

ydraulic con

tainmen

t. Not effe

ctive for

removing mass. W

ill re

quire

pum

ping

very large volumes of

clean water. W

asteful.

Extrem

ely challenging to im

plem

ent d

ue to

large siz

e of

requ

ired eq

uipm

ent, lack of land space, and

need for

perpetual ope

ratio

n and mainten

ance.

Very high. > $1 million

No additio

nal ben

efit to th

e riv

er.

Not fe

asible.

Hot S

pot R

emoval

Mass R

emoval

Soil Excavatio

nEffectiven

ess is q

uestionable. Arsen

ic is present in

backgroun

d (upstream) groun

dwater and

surface water from

the riv

er

recharging

the alluvial aqu

ifer, and it is also naturally

occurring in th

e alluvial aqu

ifer.

Extrem


plem

ent d

ue to

the ne

ed to

excavate below

the water ta

ble, large siz

e of re

quire

d eq

uipm

ent, and lack of land space. It m

ay be logistically

impo

ssible to

excavate arou

nd existing infrastructure.


No additio

nal ben

efit to th

e riv

er.

Not fe

asible.

Containm

ent

Physical Con

tainmen

tSheet P

ile W

all

Not effe

ctive for con

tainmen

t. A sheet p

ile wall only provides

a ho

rizon

tal barrie

r to flo

w. V

ertical flow

will occur

unde

rneath th

e sheet p

ile wall. May be de

trim

ental because a

sheet p

ile wall cou

ld increase re

ducing

con

ditio

ns and

cause

increasin

g arsenic concen

trations.

Extrem


plem

ent d

ue to

large siz

e of

requ

ired eq

uipm


presence of

numerou

s buried utilitie

s.


No additio

nal ben

efit to th

e riv

er.

Not fe

asible.

Physical Con

tainmen

tPe

rmeable Re

activ

e Ba

rrier

(PRB

)Effective in th

e short term. N

ot effe

ctive in th

e long

term

due

to geo

chem

ical and

biological fou

ling of th

e PR

B materials.

May be de

trim

ental to remed

iatio

n already completed

by

lowering grou

ndwater pH.

Extrem


plem

ent d

ue to

large siz

e of

requ

ired eq

uipm


presence of

numerou

s buried utilitie

s.


No additio

nal ben

efit to th

e riv

er.

Not fe

asible.

Natural Atten

uatio

nNatural Atten

uatio

nEffectiven

ess h

as alre

ady be

en dem

onstrated. Historical

quarterly

mon

itorin

g data over m

ore than

two years sho

w

stabilizatio

n of pH and arsenic in groun

dwater.

Readily im

plem

entable.

Low, due

to adm

inistrativ

e and

consultin

g fees. ~ $10

kNatural atten

uatio

n has stabilized

resid

ual levels o

f arsen

ic.

Feasible.

In‐Situ

Treatmen

tAir S

parging

Air S

parging

May be effective for creating oxidizing

con

ditio

ns and

im

mob

ilizin

g arsenic. Not effe

ctive for rem

oving mass.

Heterogene

ity of the

aqu

ifer m

ay cause chann

eling and lim

it effectiven

ess.

Challenging to im

plmen

t due

to lack of land space, and

ne

ed fo

r perpe

tual ope

ratio

n and mainten

ance.


No additio

nal ben

efit to th

e riv

er.

Not fe

asible.

Preven

ting Biological Activity

Aquifer S

teriliza

tion

Tempo

rarily effective. Not effe

ctive in th

e long

term

, due

to

impracticability of p

erpe

tually m

aintaining

sterile con

ditio

ns

in th

e aquifer.

Extrem


plem

ent d

ue to

large siz

e of

requ

ired eq

uipm

ent a

nd lack of land space. Not a proven

techno

logy.


No additio

nal ben

efit to th

e riv

er.

Not fe

asible.

In‐Situ

Che

mical Oxidatio

nKM

nO4 Injection

Tempo

rarily effective. Not effe

ctive in th

e long

term

due

to

wash‐ou

t of the

permanganate and

return to

redu

cing

geoche

mical con

ditio

ns. H

eterogen

eity of the

aqu

ifer m

ay

cause channe

ling and lim

it effectiven

ess.

Implem

entable. In

order to

be effective, will have to have

multip

le KMnO

4 injections per year o

n a pe

rpetual basis.


No additio

nal ben

efit to th

e riv

er.

Not fe

asible.

Remed

ial Screening

Table

Page 1 of 1

3/6/20

16

EXHIBIT D


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Cherry Creek

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Harvard Gulch

Cherry Creek

Lakewood Gulch

WeirGulch

Sanderson Gu lch

Bear Creek

§̈¦70

§̈¦225

§̈¦25

§̈¦76

§̈¦270

£¤36

£¤285

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1762

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63468

670

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Overall WQ Study Basin ScoringCity & County of Denver Stormwater Quality Planning

Legend

City & County Boundary

Stream/River

WQ Map Unit Boundary

Overall WQ Score

<= 49

50 - 56

57 - 61

62 - 66

67 - 70

Map ID WQ Map Unit1 Elyria / Swansea2 Globeville3 Berkeley Lake4 Sunnyside / 3115 Sloan's Lake / Highland6 Weir Gulch7 Valverde8 Sanderson Gulch9 Bear Creek10 Marston Lake11 West Washington Park12 Overland / University13 Harvard Gulch14 Goldsmith Gulch15 Cherry Creek Reservoir16 Upper Cherry Creek17 Cherry Creek Mall18 Central Platte Valley / CBD19 Five Points / Capitol Hill20 City Park / Park Hill21 West Harvard Gulch22 Westerly Creek23 NE Park Hill24 South Stapleton25 North Stapleton26 Montbello27 Irondale Gulch28 Green Valley Ranch29 Gateway30 DIA31 Lakewood Gulch

468

Map IDScore

EXHIBIT E


The Asbury & Tejon Park was constructed on a natural drainageway and provides both stormwater conveyance and stormwater deten-tion. Two pipes enter the northern parcel, a 48” RCP from S. Vallejo Street and second pipe from Tejon Street. Water flows to the south-ern end of the park via a concrete trickle channel where it exits on the southeast end through a 36” pipe. The pipe travels along West Evans where it eventually daylights through two outfalls into the river just south of Jewell Avenue. The park provides the following detention volumes during storm events: • 2-year: 0.85 ac-ft • 5-year: 1.88 ac-ft

The park currently does not provide any formalized water quality benefits.

The proposed regional BMP project could treat up to 122-acres of tributary area in one of Denver’s high priority basins. There are two distinct outfalls which can be handled separately by two different BMPs. The upper park BMP selected for this location is an EDB with bioretention and the lower park BMP is a grass-lined bioretention basin. Each BMP could provide the entire WQCV of their respective upstream tributary areas. The proposed EDB could provide 2.0 ac-ft of treatment volume in primarily existing open turf-grass areas. In addition to the water quality benefits supplied by the project, it provides flood attenuation for the minor storm. The park currently provides this flood attenuation benefit but could be increased to fully capitalize the opportunity.

Design ConsiderationsThe EDB would be constructed on-line, but could still treat dry weather flows with the use of a multi-stage outlet structure near Asbury Ave. The existing concrete low flow channel should be relocated to the east side of the park along with a steeper slope to make the grass area more usable during dry periods. The park should slope up, to the west to match grade and provide a relatively flat recreational area at the bottom of the EDB. A pre-treatment forebay is critical to prevent large trash and debris from entering the primary areas of the park and preventing the bottom of the EDB from getting clogged.

Similar multi-purpose fields and basins have been constructed throughout the country and are excellent ways of capitalizing on limited space. A key design element is the use of sand grown sod instead of conventional sod along the bottom of the basin. Sand grown sod allows for a higher infiltration rate through the bottom of the basin and into the sub-drain system. The

Project SnapshotProject Location | Asbury & Tejon Park (upper)Site Owner | Denver ParksSite Land Use | ParkSite Area (AC) | 1.9Proposed BMP Type | EDBTotal Tributary Area (AC) | 122Required WQCV (AC-FT) | 2.0Available Storage Volume (AC-FT) | 2.0Additional WQCV Needed Upstream (AC-FT) | NoneDry Weather Flow Treatment Possible | YesBasin Score | 68Sub-basin Score | Varies (29 to 33)BMP Opportunity Score | 47

[ Asbury and Tejon Park ]A

• 10-year: 3.37 ac-ft • 100-year 13.95 ac-ft

EXHIBIT E


Water Quality Impacts: Upper ParcelTrib. Area Domin. Land Use Residential

Trib. Area Composit Imp 45%

Indicator (Totals) Influent Effluent Reduct.Flow (ac-ft/yr) 49 35 30%

TSS (lb/yr) 10 - 16 2 - 3 50 - 90%Phosph (lb/yr) 38 - 52 9 - 12 60% - 80%Nitrogen (lb/yr) 340 - 470 80 - 110 60% - 80%

Zinc (lb/yr) 6 - 12 1 - 3 30% - 90%Copper (lb/yr) 1.6 - 3.0 0.4 - 0.9 40% - 90%

E.Coli (bill. cfu/yr) 830 - 1710 80 - 330 30% - 60%

Total Arsenic (lb/yr) 0.17 - 0.24 0.09 - 0.12 40% - 60%

Total Cadmium (lb/yr) 0.13 - 0.13 0.02 - 0.10 10% - 40%

Total Chromium (lb/yr) 0.28 - 0.84 0.14 - 0.31 40% - 90%

high infiltration rate is critical for opening the field after a rain event while minimizing the damage that could be caused by using the field immediately after a rain storm. The forebay and low flow channel keep the field playable during dry periods while utilizing the full field during storm events. An overflow bypass ensures the rest of the project site can remain usable immediately after storm events. A detailed hydrological analysis should be conducted during the preliminary design phase to determine the available capacity of the 48-in storm drain under Asbury Ave. The multi-stage outlet structure should allow for treated flows to bypass the lower park BMP by keeping discharges in a pipe below the downstream bioretention basin.

Tributary Area

page 93

ROW/Other 21%

Residential 41%

Commercial32%

Open Space6%

TRIBUTARY AREA

PROJECT DETAIL

Storm Drain PipePondExisting Treatment

EXISTINGTributary Area Storm Drain PipeDiversion Structure

PROPOSEDChannelEDBBioretention

Water Quality Impacts: Lower ParcelTrib. Area Domin. Land Use Residential

Trib. Area Composit Imp 51%

Indicator (Totals) Influent Effluent Reduct.Flow (ac-ft/yr) 66 31 50%

TSS (lb/yr) 12 - 21 2 - 4 50% - 90%Phosph (lb/yr) 45 - 63 11 - 15 60% - 80%Nitrogen (lb/yr) 430 - 600 110 - 150 60% - 80%

Zinc (lb/yr) 8 - 16 2 - 4 30% - 90%Copper (lb/yr) 2.2 - 3.9 0.6 - 1.2 40% - 90%

E.Coli (bill. cfu/yr) 730 - 1490 60 - 260 64% - 83%

Total Arsenic (lb/yr) 0.23 - 0.32 0.08 - 0.11 50% - 70%

Total Cadmium (lb/yr) 0.18 - 0.18 0.02 - 0.08 20% - 60%

Total Chromium (lb/yr) 0.38 - 1.13 0.13 - 0.28 50% - 90%

EXHIBIT E


Improving Neighborhood Health Through Green Infrastructure

[ Case Study: Opportunities for College View/South Platte Neighborhood ]

B

College ViewNeighborhood

South PlatteNeighborhood

The Asbury and Tejon Park is located within the College View/South Platte neighborhood in southwest Denver. This neighborhod is a predominantly Hispanic community with many children and youth, as well as a small but significant Asian population. Residents face a range of obstacles to access positive health and socioeconomic opportunities compared with Denver overall. Almost twice as many families live in poverty as in Denver overall, and almost half lack a high school diploma. In addition to financial and educational barriers, the health status of

Map representing percent tree canopy by Census Block Group

Source: Denver Parks and Recreation, 2014

College View/South Platte residents is worse than Denver overall, particularly for adult obesity and life expectancy. The built environment lacks elements to support good health, including nearby access to parks or green space, and limited tree canopy cover to mitigate heat. This is particularly critical given the neighborhood’s large youth population (31%). There is a strong relationship between children’s physical activity levels and proximity of places to be physically active. (1)

EXHIBIT E


Partnership Opportunities for Green InfrastructureGreen infrastructure has been linked to multiple positive health outcomes (see Section 2.5) and should be considered as an important tool to implement in the College Park/South Platte neighborhood for improving residents’ health and wellbeing. Existing projects and programs occuring in the neighborhood that should consider green infrastructure include:

Equity Indicators in College View/South Platte NeighorboodIndicator College View/S. Platte DenverSocio-demographic Families in poverty 34% 18%

Adults without high school diploma 44% 14%% Hispanic 70% 31%% children and youth (17 and under) 31% 21%

Health Child obesity 19% 18%Adult obesity 37% 31%Life expectancy 75 years 78 years

Built environment % within 1/4 mile walk to park or green space 36% 46%% of land that is park/open space/recreation 5% 10%% tree canopy 14.8% 15.4%Elementary school students who attend their local school

76% 62%

page 95

Safe Routes to School:• College View Elementary School has a high

percentage of students who live within one mile of the school. Many could walk or bike to school if there were routes that were safe for young pedestrians and cyclists, such as sidewalks, buffered bike lanes, and slower traffic speeds on local streets. Green infrastructure has been shown to be an effective element in slowing traffic speeds and protecting pedestrians from vehicle traffic, thereby promoting more active transportation. The Denver Safe Routes to School program worked with College View Elementary in 2015 to add 4 bike racks at the school to facilitate student biking.

Denver Community Active Living Coalition (CALC):• The Denver CALC is a Citywide advocacy group

that promotes active living, including walking, biking and transit use. In College View, resident volunteers conducted ‘walk audits’ of areas around schools, parks and recreation centers to assess ease of use and make recommendations to improve the built environment for safer walking, biking and transit use.

Federal Boulevard Corridor Plan:• The City of Denver recently released a draft Federal

Boulevard Corridor Plan, with goals that include improving mobility for all modes of travel for all users. Green infrastructure is a key component of creating safe, comfortable, accessible corridors for all ages and abilities.

Asbury and Tejon Park Redesign:• In 2016, Denver’s Parks and Recreation Department

and Public Works Department began an effort to redesign Asbury and Tejon Park. This project presents an opportunity to redesign an existing stormwater detention facility and make improvements that will not only add water quality elements to the facility but will also improve park functionality for local residents. Improvements will include converting a concrete channel to a wetland channel and moving it to the perimeter of the park in order to provide a larger playing field area.

EXHIBIT E


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