1) Xcel Energy· ~ RTsPON-s-iS-i-i:-ijY--NA-ruli-ETM

May 18, 2009

Mr. Richard Kinch

US Environmental Protection Agency (5306P)

1200 Pennsylvania Avenue, NW

Washington, DC 20460

414 Nicollet Mall

Minneapolis, Minnesota 55401-1993

Re: Xcel Energy Response to Request for Information relating to Surface

Impoundments Under 104 (e) of the Comprehensive Environmental Response,

Compensation, and Liability Act, 42 U.S.C. 9604(e).

Dear M.r.Kinch:

Please find enclosed the response from:

- Public Service Company of Colorado (PSCo), a Colorado corporation;

- Northern States Power Company of Minnesota (NSP-M), a Minnesota

corporation, and;

Northern States Power Company of Wisconsin (NSP-W), a Wisconsin

corporation;

all d/b/a Xcel Energy Inc., related to the US Environmental Protection Agency's

(EPA) "Request for Information" received May 4, 2009 for surface impoundments

that are used to manage coal combustion residuals or byproducts at our coal

fired generation plants. This response addresses the nine additional facilities

Xcel Energy identified in a letter to EPA dated April 17, 2009, specifically:

• NSP-W Bay Front Plant in Ashland, Wisconsin

• NSP-M Minnesota Valley Plant in Granite Falls, Minnesota

• PSCo Arapahoe Station in Denver, Colorado

• PSCo Cameo Station in Grand Junction, Colorado

• PSCo Cherokee Station in Denver, Colorado

• PSCo Comanche Station in Pueblo, Colorado

• PSCo Hayden Station in Hayden, Colorado

• PSCo Pawnee Station in Brush, Colorado

• PSCo Valmont Station in Boulder, Colorado

We are consolidating and submitting the requested information for the nine

facilities as attachments to this letter. The responses are organized by plant to

respond to the questions posed in the US EPA letter.
In an effort to assist the agency in its collection of information, we are also

providing copies of those documents where available, which EPA has identified

in/its request for information.

We have made every effort to fully respond to EPA's request for information in

the very limited amount of time that was provided to us and despite the

ambiguous nature of several of the requests. To the best of my knowledge, the

information contained in this response is true, accurate, and complete, as of this

date. Please direct any questions concerning this submittal to my attention at the

address listed below.

Sincerely,

Terry E. Coss, PE

Environmental Director

Xcel Energy

414 Nicollet Mall

Minneapolis, MN 55401

5-Ig- ...uc)1 Date

Attachment 1: NSP-W Bay Front Plant

Attachment 2: NSP-M Minnesota Valley Plant

Attachment 3: PSCo Arapahoe Station

Attachment 2: PSCo Cameo Station

Attachment 3: PSCo Cherokee Station

Attachment 4: PSCo Comanche Generating Plant

Attachment 5: PSCo Hayden Station

Attachment 6: PSCo Pawnee Station

Attachment 7: PSCo Valmont Station
US EPA Request for Information relating to Surface Impoundments

Date: May 18,2009

Attachment 1: NSP-W Bay Front Plant

Bay Front Plant is reporting on the following two surface impoundments:

• Surge Basin

• Polishing Pond

Note that the polishing pond is likely beyond the scope of EPA's

information request, given its primary purpose is not to store or dispose of

coal combustion residuals or byproducts. However, we are including a

description of this surface impound~ent for purposes of completeness

and due to the ambiguous nature of EPA's request.

Background:

The Bay Front Plant has two settling ponds that are connected in series.

The first pond, called the Surge Basin, is the primary settling pond for

process waste solids, including ashfines/slag. The second pond, called

the Polishing Basin, contains small amounts of process waste due to carry

over from the Surge Basin. Surface discharges from the basins are

monitored and reported under a state issued NPDES permit.

Fly ash and bottom ash produced at the plant are managed in silos and

trucked off-site for beneficial reuse.

The Surge Basin will generally accumulate about 2,000 cubic feet of

process waste annually. The Polishing Basin will accumulate about 90

cubic feet annually. The Surge Pond is typically dredged annually and the

polishing pond is dredged as needed. The materials dredged from the

ponds are dewatered and trucked off site for beneficial reuse.

Response to the US EPA Questions

1. Relative to the National Inventory of Dams criteria for High, Significant,

Low or Less-than-Low, please provide the potential hazard rating for each

management unit and indicate who established the rating, what the basis

of the rating is, and what federal, or state agency regulates the unites). If

the unites) does not having a rating, please note that fact.

The Surge Basin and Polishing Basin have not been rated by any

agency under the National Inventory of Dams criteria. Based on the

NID criteria, the two management units would not meet the minimum

size for a classification rating.

Pg. 1
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 1: NSP-W Bav Front Plant

2. What year was each management unit commissioned and expanded?

The basins were constructed in 1976.

3. What materials are temporarily or permanently contained in the unit? Use

the fol/owing categories to respond to this question: (1) fly ash; (2) bottom

ash; (3) boiler slag; (4) flue gas emission control residuals; (5) other. If the

management unit contains more than one type of material, please identify

aI/ that apply. Also, if you identify "other," please specify the other type of

materials that are temporarily or permanently contained in the unites).

The Surge Basin temporarily stores siagfines that are part of the

process water treatment at the plant. The Polishing Basin contains

process water and only de-minimis solids, such as slag fines or

sediments, that may be carried over Jrom the Surge Basin.

4. Was the management unites) designed by a Professional Engineer? Is or

was the construction of the waste management unites) under the

supervision ofa Professional Engineer? Is inspection and monitoring of

the safety of the waste management unites) under the supervision of a

Professional Engineer?

The two basins were designed and certified by a Professional

Engineer in 1976. We were unable to locate any documentation

demonstrating that the construction was· under the supervision of a

Professional Engineer

5. When did the company last assess or evaluate the safety (i.e., structural

integrity) of the management unites)? Briefly describe the credentials of

those conducting the structural integrity assessment/evaluations. Identify

actions taken or planned by facility personnel as a result of these

assessments or evaluations. If corrective actions were taken, briefly

describe the credentials of those performing the corrective actions,

whether they were company employees or contractors. If the company

plans an assessment or evaluation in the fqture, when is it expected to

occur?

We could not locate records documenting that the pond has been

evaluated for structural integrity. NSP-W completed a field study as

part of meeting the requirements of the State of Wisconsin

Administration Code NR 213, "Lhling of industrial Lagoons and

Design of Storage Structures". A report issued in 1992, completed

by a Professional Engineer, confirmed the storage ponds met or

Pg.2
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 1: NSP-W Bav Front Plant

exceeded the requirements of NR213. A letter is attached from the

Wisconsin DNR documenting their review of the 1992 report and

agreeing with the findings.

6. When did a State or a Federal regulatory official last inspect or evaluate

the safety (structural integrity) of the management unites)? If you are

aware of a planned state or federal inspection or evaluation in the future,

when is it expected to occur? Please identify the Federal or State

regulatory agency or department which conducted or is planning the

inspection or evaluation. Please provide a copy of the most recent official

inspection report or evaluation.

Wisconsin does·notrecogniz,e the two basin~ as dams and there

have been n6 state or federa'l inspections recorded related to the

structural integrity of theseinanagement units. To our knowledge

there are no State or Fede~al.inspections planned.

7. Have assessments or evaluations, or inspections conducted by State or

Federal regulatory officials conducted within the past year uncovered a

safety issuers) with the management unites), and, if so, describe the

actions that have been or are being taken to deal with the issue or issues.

Please provide any documentation that you have for these actiqns.

Not Applicable - Refer to item 6.

8. What is the surface area (acres) and total storage capacity of each of the

management units? What is the volume of materials currently stored in

each of the managementunit(s)? Please provide the date that the volume

measurement(s) was taken. Please provide the maximum height of the

management unites). The basis for determining maximum height is

explained later in this Enclosure.

Based on the engineering study completed in 1976, the Surge Basin

is an earth embankment with the berm height of 9.5 ft. measured

from the downstream toe to the embankment crest. The Polishing

Basin is an earth embankment with a berm height of 7.5 ft.

The surface area and maximum volume (at the embankment crest) of

the Surge Basin are 0.15 acres and 2,200 cubic yards, respectively.

The surface area and maximum volume (at the embankment crest) of

the Polishing Basin are 0.41 acres and 4,980 cubic yards,

respectively.

Pg. 3
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 1: NSP-W Bay Front Plant

9. Please provide a brief history of known spills or unpermitted releases from

the unit within the last ten years, whether or not these were reported to

State of federal regulatory agencies. For purposes of this question,

please include only releases to surface water or to the land (do not include

releases to groundwater).

We have found no record of known spills or unpermitted releases

from the ponds to surface waters or land during the past 10 years.

10.Please identify all current legal owners(s) and operator(s) at the facility.

The Bay Front Plant is owned by Northern States Power Company -

Wisconsin, a subsidiary of Xcel Energy Inc.

Pg.4
US EPA Request for Information relating to Surface Impoundments

Date:. May 18, 2009

Attachment 2: NSP-M Minnesota Vallev Plant

Minnesota Valley Plant .is reporting on fCl)ursurface impoundments, referred

to as Ponds 1, 2, 3 and 4.

Background:

The Minnesota Valley Plant is ourrently inactive and has not produced

significant amounts of ash for the last 10 years. When the plant operates,

the fly and bottom ash are combined before being hydraulically transported

to a four pond settling system. The settling treatment occurs in a series of

three ponds. The first pond in the series has historically alternated

between pond 1 or pond 2 (parallel operation). Surface discharges from

the ponds are monitored and reported u!nder a state issued NPDES permit.

For the past 20 years, Pond 1 has served as the primary storage facility for

solids accumulations from the other ponds .. The combined ash is stored

in Pond 1 until it is full. The pond is then dredged as needed to maintain

capacity, and then the ash is dewatered.and transported by truck to a dry

disposal facility.

All of the ponds are located below grade on three sides, with the fourth

side adjacent to the river being an earth embankment. Pond No.1's west

side is a combination of natural material and earthen embankment.

Pond 1 currently contains combined ash. The ash has been dry stacked

above the top of the pond but graded s() that runoff is controlled within the

pond.

The ponds are subject to periodic visual inspections by plant personnel.

Response to the US EPA Questions

1. Relative to the National Inventory of Dams criteria for High, Significant, Low

or Less-than-Low, please provide the potential hazard rating for each

management unit and indicate who established the rating, what the basis of

the rating is, and what federal, or state agency regulates the unites). If the

unites) does not having a rating, please note that fact.

None of the four ponds noted above have been rated by any agency

under the National Inventory of Dams. Based on the NID criteria, the

four ponds would be classified as low hazard.

2. What year was each management unit commissioned and expanded?

Pg. 1
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 2: NSP-M Minnesota Vallev Plant

Ponds 1 and 2 were put into service as part of a new unit being

installed in the early 1950's. Ponds 3 and 4 were added to the site in

1975.

3. What materials are temporarily or permanently contained in the unit? Use

the following categories to respond to this question: (1) fly ash; (2) bottom

ash; (3) boiler slag; (4) flue gas emission control residuals; (5) other. If the

management unit contains more. than one type of material, please identify

all that apply. Also, if you identify "other, " please specify the other type of

materials that are temporarily or permanently contained in the unites).

A combination of fly ash and bottom ash are temporarily deposited in

the pond system. The ash that accumulates in the other ponds is

transferred, as needed, for temporary storage in Pond 1. As noted

above, this first pond is periodically dredged and any material

removed is dewatered and trucked off-site for dry disposal.

4. Was the management unit(s) designed by a Professional Engineer? Is or

was the construction of the waste management unit(s) under the

supervision 6f a Professional Engineer? Is inspection and monitoring of

the safety of the waste management unit(s) under the supervision of a

Professional Engineer?

The original ponds were designed as part of the original plant design.

We were unable to locate any documentation that the plans were

prepared and signed by a Professional Engineer. We could not find

documentation that the ponds added in the 1970's were designed by a

Professional Engineer. A hydtologic analysis of the ponds was

completed in 1996, but the structural integrity of the earth

embankments was not addressed.

5. When did the company last assess or evaluate the safety (i.e., structural

(ntegrity) of the management unit(s)? Briefly describe the credentials of

those conducting the structural integrity assessment/evaluations. Identify

actions taken or planned by facility personnel as a result of these

assessments or evaluations. If corrective actions were taken, briefly

describe the credentials of those performing the corrective actions, whether

they were company employees or contractors. If the company plans an

assessment or evaluation in the future, when is it expected to occur?

No record of any structural integrity assessment of the ponds has

been found. Given the low risk of a structural failure, the company

Pg.2
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 2: NSP-M Minnesota Vallev Plant

has no current plans to complete a structural assessment in the

future.

6. When did a State or a Federal regulatary afficiallast inspect ar evaluate the

safety (structural integrity) afthemanagement unites)? Ifyau are aware af

a planned state ar federal inspectian ar evaluatian in the future, when is it

expected to.accur? Please identify the Federal ar State regulatary agency

ar department which canducted Dr is planning the inspectian or evaluatian.

Please provide a capy af the mast recent afficial inspectian repart ar

evaluatian.

The Minnesota Department of Natur,al Resources, Dam Safety Unit,

does not recognize any of the ponds as dams and there have been no

state or federal inspections recorded related to the structural integrity

of these management units. To our knowledge, there are no

inspections planned for these management units.

\".', '. " ,

7. Have assessments qr evall!;ations,or inspectians, Gonaucted by State ar

Federal regulatary afficials conqucted within the past year uncavered a

safety issuers) with thf] man,agern,ent unites), and, if sa, describe the

actians that have been ar are being takim to.deal with the issue ar issues.

Please provide any dacumentatian that yau have far these actians.

Not Applicable - Refer to item 6.

8. What is the surface area (acres) and tatal starage capacity af each af the

management units? What is the valume af materials currently stared in

each afthe management unites)? Please provide the date that the valume

measurement(s) was taken. Please provide the maximum height af the

management unites). The basis far determining maximum height is

explained later in this Enclasure.

The four ponds each have a surface area approximately three quarter

of an acre. As noted above, the crest of the ponds is at grade except

for the sides adjacent to the Minnesota River. The constructed earth

embankment height for the ponds is approximately 6 ft, but adding

the natural riverbank, the total height is approximately 15 ft. from toe

of the river to the embankment crest. Approximately half that height

is below the river pool elevation during normal conditions.

The average depth of Ponds 1.and 2 is approximately 12 ft.,

corresponding to the height of the earth embankment plus the basin

formed by the excavation of natural soils from inside of the pond.

Pg. 3
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 2: NSP-M Mi,nnesota Vallev Plant

The resulting maximum volume of these ponds is estimated at 9 acreft (12,000 cubic yards) of storage (both solids and water). The depth

of Ponds 3 and 4 are approximately 9 ft, resulting in a maximum

volume of 7 acre-ft (10,800 cubic yards) of storage (both solids and

water).

Pond 1 is almost full. Pond 2 contains ash amounting to more than

half its total volume. The 'ash volume in the other two ponds is less

than 25 percent of their total volume.

9. Please provide a brief history of known spills or unpermitted releases from

the unit within the last ten years, wh~ther or not these were reported to

State of federal regulatory agencies. For purposes of this question, please

include only releases to surface water or to the land (do not include

releases to groundwater).

We have found no record of known spills or unpermitted releases

from any of the ponds to surface waters or land during the past 10

years. The ponds have been overtopped during flood events on the

Minnesota River in 1997 and 2001, which could have resulted in some

ash being carried away by floodwaters.

10. Please identify all current legal owners(s} and operator(s} at the facility.

The Minnesota Valley Generating Facility is owned by Northern

States Power Company - Minnesota, a subsidia.ry of Xcel Energy Inc.

Pg.4
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 3: PSCo 'Arapahoe Station

Arapahoe Station is reporting on the following six surface impoundments:

• North Storm Water / Process Water Pond

• South Storm Water / Process Water Pond

• South Ash Pond

• Emergency Pond

• Discharge Pond

• Ash Pump Pond

Note that many, if not all of these surface impoundments are likely beyond

the scope of EPA's information requestt given their incised/below-grade

nature, and/or the fact that their primary purpose is not to store or dispose

of coal combustion residuals or byproducts. However, we are including a

description of these surface impoundments for purposes of completeness

and due to the ambiguous nature of EPA's request.

Background: '. ,I

The first three ponds listed above were formerly used to settle bottom ash

out of the process water. The water then flowed through the Emergency

Pond and Discharge Pond, mixing with other plant process wastewater

prior to discharge in accordance with a State-issued NPDES permit. In

June 2005 an ash dewatering system was built eliminating the need for ash

settling ponds, and the first three ponds listed above were dredged to

remove residual ash and subsequently repurposed. These three ponds

now have the potential to receive process water during plant upsets. The

North and South Storm Water Ponds also receive stormwater.

The Emergency Pond and the Discharge Pond currently receiveblow-down

water from the circulating water system, other process wastewater, and

stormwater.

The Ash Pump Pond was never used for ash settling; its name derives from

its use to pump makeup water to the bottom ash sluicing system. This

pond does occasionally receive small amounts of process water from the

ash dewatering system, as well as storm water and other plant waste-water

streams. The water from this pond flows to the Emergency Pond and/or

Discharge pond.

Inspections of the ponds are conducted daily for normal operation by plant

operators and chemists.

Pg. 1
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 3: PSCo Arapahoe Station

1. Relative to the Nationallnventoty of Dams criteria for High, Significant,

Low or Less-than-Low, please provide the potential hazard rating for each

management unit and indicate who established the rating, what the basis

of the rating is, and what federal, or state agency regulates the unites). If

the unites) does not having a rating, please note that fact.

All six ponds are incised (below-grade), and none have been rated by

any agency under the National Inventory of Dams, nor would we

expect them to meet the minimum threshold for any such rating.

2. What year was each management unit commissioned and expanded?

The original plant pond design consisted of one large ash settling

pond put into service when the plant became operational in 1950. In

about 1965 (exact date unknown), five separate and smaller ponds

(the North Storm Water I Process Water Pond, South Storm Water I

Process Water Pond, South Ash Pond, Emergency Pond, and

Discharge Pond) were constructed and put into service in the area of

the original ash-settling pond.

The Ash Pump Pond was constructed and put into service when the

plant became operational in 1950.

3. What materials are temporarily or permanently contained in the unit? Use

the following categories to respend to this question: (1) fly ash; (2) bottom

ash; (3) boiler slag; (4) flue gas emission control residuals; (5) other. If the

management unit contains more than one type of material, please identify

all that apply. Also, if you identify "other," please specify the other type of

materials that are temporarily or permanently contained in the unites).

Three ponds (the North.Storm Water I Process Water Pond, South

Storm Water I Process Water Pond, and the South Ash Pond) were

formerly used to settle out and temporarily store bottom ash

generated at the facility. These three ponds are no longer used for

settling ash, and were dredged to remove bottom ash subsequent to

construction of the ash dewatering system. They may now receive

water from the Ash Pump Pond.

The Emergency Pond and Discharge Pond are no longer used to

process ash, but still contain some residual bottom ash from former

plant operations. They are now used to settle suspended solids and

Pg.2
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 3: PSCo Arapahoe Station

control water chemistry from other plant wastewater prior to

discharge under the NPDES permit.

An ash dewatering system is now in use and occasionally process

water from that system is discharged to the Ash Pump Pond.

4. Was the management unites) designed by a Professional Engineer? Is or

was (he construction of the waste management unites) under the

supervision of a Professional Engin~er? Is inspection and monitoring of

the safety of the waste management unites) under the supervision of a

Professional Engineer?

No plant documentation was· located to demonstrate that the ponds

were designed by or construction supervised by a Professional

Engineer.

5. When did t/Je company last assess brevaluate the safety (i.e., structural

integrity) of the management,unit(s)? Briefly describe the credentials of

those conducting the struc.tu(alintegrity assessment/evaluations. Identify

actions taken or planned by facility personnel as a result of these

assessments or evaluations. If corrective actions were taken, briefly

describe the credentials of th.oseperforming tbe corrective actions,

whether they were company employees or contractors. If the company

plans an assessment or evaluation in the future, when is it expected to

occur?

No record of any structural integrity assessment of the ponds was

found, nor would we expect such an assessment to have been

performed given they are below-grade, incised ponds.

There are no plans to evaluate the structural integrity of these ponds

in the future.

6. When did a State or a Federal regulatory official last inspect or evaluate

the safety (structural integrity) of the management unit(s)? If you are

aware of a planned state. or federal inspection or evaluation in the future,

when is it expected to occur? Please identify the Federal or State

regulatory agency or department which conducted or is planning the

inspection or evaluation. Please provide a copy of the most recent official

inspection report or evalu§1tion

There have been no state or federal in$pections recorded related to

the structural integrity of these management units. To the best of

Pg. 3
US EPA Request for Information relating·to Surface Impoundments

Date: May 18, 2009

Attachment 3: PSCo Arapahoe Station

our knowledge, there are no inspections planned for these

management units.

7. Have assessments or evaluations, or inspections conducted by State or

Federal regulatory officials cond~'cted within the past year uncovered a

safety issuers) with the management unites), and, if so, describe the

actions that have been or are b~ing taken to deal with the issue or issues.

Please provide any documentation that you have for these actions.

Not applicable - refer to item 6.

8. What is the surface area (acres) and total storage capacity of each of the

management units? What is the volume of materials currently stored in

each of the management unites)? Please provide the date that the volume

measurement(s) was taken. Please provide the maximum height of the

management unites). The basis tor determining maximum height is

explained later in this Enclosure.

The Emergency Pond is 1.6 acres in size, with a capacity of

approximately 19,500 cubic yards. The pond is entirely below grade,

and therefore per Enclosure A to EPA's letter, no volume or height

information is reported ..

The Discharge Pond is 0.86 acres in size, with a capacity of

approximately 11,800 cubic yards. The pond is entirely below grade,

and therefore per Enclosure A to EPA's letter, no volume or height

information is reported.

The South Storm Water I Process Water Pond is 0.89 acres in size,

with a capacity of approximately 22,500 cubic yards. The pond is

entirely below grade, and therefore per Enclosure A to EPA's letter,

no volume or height information is reported.

The Ash Pump Pond is 0.32 acres in size, with a capacity of

approximately 5,700 cubic ya~ds. The pond is entirely below grade,

and therefore per Enclosure A to EPA's letter, no volume or height

information is reported.

The South Ash Pond is 0.87 aCres in size, with a capacity of

approximately 21,800 cubic yards. The pond is entirely below grade,

and therefore per Enclosure A to EPA's letter, no volume or height

information is reported.

Pg.4
us EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 3: PSCo Arapahoe Station

The North Storm Water I Process Water Pond is 1 acre in size, with a

capacity of approximately 13,000 cubic yards. The pond is entirely

below grade, and therefore per Enclosure A to·EPA's letter, no

volume or height information is reported.

9. Please provide a brief history of known spills or unperri1itted releases from

the unit within the last ten yearS, whether or not these were reported to

State of federal regulatory agencies. For purposes of this question,

please include only releases to surface water or to the land (do not include

releases to groundwater).

We have found no record 'of known spills or un-permitted releases

from the units to surface water or to the land within the past 10

years.

10. Please identify a/l current legal owners(s) and operator(s) at the facility.

Arapahoe Station is owned ,by Public Service. Company of Colorado,

a subsidiary of Xcel Energy Inc.

Pg, 5
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 3: PSCo Arapahoe Station

Page intentionally blank

Pg.6
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 4: PSCo Cameo Station

Cameo Station is reporting on the following two surface impoundments:

• Process Water Retention Pond

• Ash Silo Storm Water Retention Pond.

Note that these surface impoundments ,arelikely beyond the scope of

EPA's information request, given their ircised/below-grade nature, and/or

th~ fact that their primary purpose is nqt to store or dispose of coal

combustion residuals or byproducts. Hbwever, we are including a

description of these surface impoundm~nts for purposes of completeness

and due to the ambiguous nature of EPA's request

Background:

The Process Water Retention Pond, a below-grade incised pond, is

used to control pH from the boiler blow down, capture small

amounts of ash carried from the floor drains· of the plant, and to hold

other plant process wastewater.

The Ash Silo Storm Water Retention Pond was originally a ditch next

to the railroad right of way that was dammed at one end to create a

pond. This pond captures stormV!'ater runoff and water from the daily

wash down of the ash silo and surrounding area.

The ponds are visually inspected daily by plant personnel.

1. Relative to the National Inventory of Dams criteria for High, Significant,

Low or Less-than-Low, please provide the potential hazard rating for each

management unit and indicate who established the rating, what the basis

of the rating is, and what federal, or state agency regulates the unit(s). If

the unit(s) does not having a rating, please note that fact.

Neither of the two ponds listed a~ove have been rated by any agency

under the National Inventory of Dams, nor do we believe either pond

meets the minimum threshold to be rated.

2. What year was each management unit commissioned and expanded?

The date of construction of the ppnds is unknown, but is.believed to

coincide with plant construction In 1956.

3. What materials are temporarily or permanently contained in the unit? Use

the following categories to respond to this question: (1) fly ash; (2) bottom

Pg.1
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 4: PSCo Cameo Station

ash; (3) boiler slag; (4) flue gas emission control residuals; (5) other. If the

management unit contains more' than one type of material, please identify

all that apply. Also, if you identify "other, " please specify the other type of

materials that are temporarily or permanently contained in the unites).

The Process Water Retention Pond is used to settle suspended

solids and control water chemistry prior to discharge under an

NPDES permit. It also captur~sminor amounts of fly ash and bottom

ash carried from the floor drains of the plant.

The Storm Water Retention Pond captures stormwater runoff and

water from the daily wash down of the ash silo and surrounding area.

It contains small amounts of fly ash and bottom ash from these

activities.

4. Was the management unites) designed by a Professional Engineer1 Is or

was the construction bfthe waste management unites) under the

supervision of a·Professional Engineer? Is inspection and monitoring of

the safety of the waste management unites) under the supervision of a

Professional Engineer1

The ponds were designed as part of the original plant design.

However, no documentation cpold be found to demonstrate that a

Professional Engineer certified the design or supervised the

construction of the ponds.

5. When did the company last assess or evaluate the safety (i.e., structural

integrity) of the management unites)? Briefly describe the credentials of

those conducting the structural integrity assessment/evaluations. Identify

actions taken or planned by facility personnel as a result of these

assessments or evaluations. If corrective actions were taken, briefly

describe the credentials of those performing the corrective actions,

whether they were company employees or contractors. If the company

plans an assessment or evaluation in the future, when is it expected to

occur1

No record of any structural integrity assessment of the ponds was

found.

There are no plans to evaluate the structural integrity of these ponds

in the future, due to their small size and configuration.

Pg. 2
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 4: PSCo Cameo Station

6. When did a State or a Federal regulatory official last inspect or evaluate

the safety (structural integrity) of the management unit(s)? If you are

aware of a planned state or federal inspection or evaluation in the future,

when is it expected to occur? Plea~e identify the Federal or State

regulatory agency or department which conducted or is planning the

inspection or evaluation. Please provide a copy of the most recent official

inspection report or evaluation.

There have been no State or Federal inspections recorded related to

the structural integrity of these management units. To the best of

our knowledge, there are no inspections planned for these

management units.

7. Have assessments or evaluations, or inspections conducted by State or

Federal regulatory officials conducted within the past year uncovered a

safety issuers} with the maf}agementunit(s), and, if so, describe the

actions that have been or are being taken to deal with the issue or issues.

Please provide any documentation .that you have for these actions.

Not applicable - refer to item 6.

8. What is the surface area (acres) and total storage capacity of each of the

management units? What is the volume of materials currently stored in

each of the management unit(s)? Please provide the date that the volume

measurement(s) was taken. Please provide the maximum height of the

management unit(s). The basis for determining maximum height is

explained later in this Enclosure.

The Process Water Retention Pond is 0.3 acres in size, with a

capacity of approximately 2,520 cubic yards. The pond is entirely

below grade,·and therefore per Enclosure A to EPA's letter, no

volume or height information is reported.

The Storm Water Retention Pond is 0.05 acres in size, with a capacity

of approximately 1,000 cubic yards. The pond is about half-full,

primarily water with minor amounts of solid material, so the

approximate volume stored is 500 CY. The stored volume was

visually estimated on May 6, 2009. The maximum height of the pond

is approximately 12 feet.

9. Please provide a brief history of known spills or unpermitted releases from

the unit within the last ten years, whether or not these were reported to

State of federal regulatory agencies. For purposes of this question,

Pg. 3
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 4: PSCo Cameo Station

please include only releases to surface water or to the land (do not include

releases to groundwater).

We have found no record of known spills or un-permitted releases

from the units to surface wate.r or to the land within the past 10

years.

10.· Please identify all current legal owners(s) and operator(s) at the facility.

Cameo Station is owned by Public Service Company of Colorado, a

subsidiary of Xcel Energy Inc.

Pg.4
us EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 5: PSCoCherokee Station

Cherokee Station is reporting on the following six surface impoundments:

• West Ash Pond

• Center Ash Pond

• East Ash Pond

• Emergency Spill Pond

• West Polishing Pond

• East Polishing Pond

Note that many, if not all of these surface impoundments are likely beyond

the scope of EPA's information request, given their incised/below-grade

nature, and/or the fact that their primary purpose is not to store or dispose

of coal combustion residuals or byprodllcts. However, we are including a

description of these surface impoundments for purposes of completeness

and due to the ambiguous nature of EPA's request.

Background

Cherokee Station currently collects its sluiced bottom ash in three Ash

Ponds. One pond at a time receives asl;l. Ash settles out in each of these

Ash Ponds and sluice water overflows to a lift station. This lift station

sends a mixture of ash pond water and other plant wastewater through a

clarification waste treatment system. Ifthe lift station level gets too high

the excess water bypasses the clarifier and flows to the Emergency Spill

Pond. This water is then pumped back through the clarifier. Clarified water

goes to the Polishing Ponds for pH adjustment prior to discharge in

accordance with a State-issued NPDESpermit. Ash is periodically dredged

from the ash ponds and transported offsite by truck for disposal.

Inspections of the ponds are conducted for normal operation daily by plant

operators and chemists.

1. Re/ative to the National Inventory of Dams criteria for High, Significant,

Low, or Less-than-Low, please provide the potential hazard rating for each

management unit and indicate who established the rating, what the basis

of the rating is, and what federal or state agency regulates the unit(s)./f

the unites) does not have a rating, please note that fact.

The Emergency Spill Pond has a dam on the south end that is

approximately 8 feet high. It has not been rated by any agency under

the National Inventory of Dams, nor would we expect it to meet any

minimum threshold for rating.

Pg. 1
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 5: PSCo Cherokee Station

The remaining ponds are incised (below-grade). None have been

rated by any agency under the National Inventory of Dams, nor

would we expect them to meet the minimum threshold for any rating.

2. What year was each management unit commissioned and expanded?

The three Ash Ponds were constructed and put into service in 1957.

The two Polishing Ponds and~the Emergency Spill Pond followed in

1979-1980.

3. What materials are temporarily or permanently contained in the unit? Use

the following categories to respond to this question: (1) fly ash; (2) bottom

ash: (3) boiler slag; (4) flue gas emission control residuals; (5) other. If the

management unit contains more than one type of material, please identify

all that apply. Also, if you identify "other, " please specify the other types of

materials that are temporarily or permanently contained in the unites).

The primary makeup of the ash in the three Ash Ponds is sluiced

ash, which is mainly bottom a$h. The ponds do contain minor

amounts of fly ash, boiler slag, and flue gas emission control

residuals. These ponds are periodically dredged with waste being

transported offsite for proper disposal.

The Emergency Spill Pond receives lift station overflow, coal pile

runoff and surface storm water runoff. The Emergency Spill Pond is

pumped back to the lift station for treatment as soon as possible.

The two Polishing Ponds receive treated wastewater from the

clarifier for pH adjustment prior to discharge in accordance with the

State-issued NPDES permit. The clarifier is designed to remove

solids, but the potential exists for de minimis carry-over of ash

particles to the Polishing Ponds.

4. Was the management unites) designed by a Professional Engineer? Is or

was the construction of the waste management unites) under the

supervision of a Professional Engineer? Is inspection and monitoring of

the safety of the waste management unites) under the supervision of a

Professional Engineer?

The three Ash Ponds were part of the original plant design, but no

documentation can be found showing that a professional engineer

Pg.2
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 5: PSCo Cherok~ Station

prepared or signed the ash pond plan layout, or supervised the

construction.

As for the other ponds no documentation was found that these

ponds were designed by or construction supervised by a

professional engineer

5. When did the company last assess or evaluate the safety (i.e., structural

integrity) of the management unit(s)? Briefly describe the credentials of

those conducting the structural integrity assessments/evaluations: Identify

actions taken or planned by facility personnel as a result of these

assessments or evaluations. If corrective actions were taken, briefly

describe the credentials o(tt,ose perf9rming the corrective actions,

whether they were company employees or contractors. If the company

plans an assessment or ev,aluatiofl In the future, when is it expected to

occur?· ...

No record of any structural integrity assessment of the ponds has

been found.

There are no plans to evaluat~ the structural integrity of these ponds

in the future, due to their size and configuration.

6. When did a State or a Federafregulatory official last inspect or evaluate

the safety "structural integrity) of the management unites)? If you are

aware of a planned state or federallnspec(ion or evaluation in the future,

when is it expected to occur? Please· identify the Federal or State

.regula tory agency or department which conducted or is planning the

inspection or evaluation. Please provide a copy of the most recent official

inspection report or evaluation.

There have been no State or Federal inspections recorded related to

the structural integrity of these management units. To the best of

our knowledge, there are no inspections planned for these

management units.

7. Have assessments or evaluations, or inspections conducted by State or

Federal regulatory officials conducted within the past year uncovered a

safety issue(s) with the management unit(s), and, if so, describe the

actions that have been or are being taken to deal with the issue or issues.

Please provide any documentation that you have for these actions.

Not Applicable - Refer to item 6.

Pg. 3
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 5: PSCo Cherokee Station ,

8. What is the surface area (acre's) and total storage capacity of each of the

management units? What is the·volume of material currently stored in

each of the management unit(s)~ Please provide the date that the volume

measurement(s) was taken. Please provide the maximum height of the

management unit(s). The basis for determining maximum height is

explained later in this Enclosure.

The West Ash Pond is 0.39 acres in size, with a capacity of

approximately 12,700 cubic yards. The pond is entirely below grade,

and therefore per Enclosure A to EPA's letter, no volume or height

information is reported.

The Center Ash Pond is 0.48 acres in size, with a capacity of

approximately 15,600 cubic yards. The pond is entirely below grade,

and therefore per Enclosure A to EPA's letter, no volume or height

information is reported.

The East Ash Pond is 0.~9 acres in size, with a capacity of

approximately 12,700 cubic yards. The pond is entirely below grade,

and therefore per Enclosure A to EPA's letter, no volume or height

information is reported.

The Emergency Spill Pond is p.4 acres in size, with a capacity of

approximately 7,700 cubic ya~ds. A concrete dam on the South end

is 8 feet 4 inches high from toe to crest. Current volume as

measured on May 12, 2009 is approximately 644 cubic yards, and

consists primarily of water.

The West Polishing Pond is 1 acre in size, with a capacity of

approximately 25,000 cubic yards. The pond is entirely below grade,

and therefore per Enclosure A to EPA's letter, no volume or height

information is reported.

The East Polishing Pond is 1 acre in size, with a capacity of

approximately 25,000 cubic yards. The pond is entirely below grade,

and therefore per Enclosure A to EPA's letter, no volume or height

information is reported.

9. Please provide a brief history of known spills or unpermitted releases from

the unit within the last ten years, whether or not these were reported to

State or federal regulatory agenCies. For purposes of this question, please

Pg.4
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 5: PSCo Cherokee Station

include only releases to surface water or to the land (do not include

releases to groundwater).

We have found no record of known spills or un-permitted releases

from the units to surface water orlo the land within the past 10

years.

10. Please identify all current legal owner(s) and operator(s) at the facility.

Cherokee Station is owned by Public Service Company of Colorado,

a subsidiary of Xcel Energy Inc.

Pg. 5
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 5: PSCo Cherokee Station

Page intentionally blank

Pg. 6
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 6: PSCo Comanche Station

Comanche Station is reporting on five surface impoundments:

• Ash Pond #1

• Ash Pond #2

• Ash Pond #3

• Polishing Pond (#4)

• Ash Disposal Facility (ADF) Stormwater Retention Pond

Note that some of these surface impoundments are likely beyond the scope

of EPA's information request, given their incised/below-grade nature,

and/or the fact that their primary pur;pose is not to store or dispose of coal

combustion residuals or byproducts. However, we are including a

description of these surface impoun~ments for purposes of completeness

and due to the ambiguous nature of EPA's request.

Background:

Ponds used at Comanche Station are used to manage clarifier underflow

(calcium carbonate), bottom ash solids, de minimis amounts of scrubber

solids, and other plant process wastewater. AII.of these ponds are clay

lined and are operated under a State-issued NPDES permit. Comanche

also has a storm water retention pond as part of its dry ash disposal

facility.

Clarifier underflow material is generated as part of the water treatment

process at Comanche Station. The ~alciumcarbonate is hydraulically

transported from the clarifiers to As~ Ponds 1 & 2 to allow for settling of

solids and dewatering in preparation for permanent disposal. De minimis

amounts of scrubber solids are also disposed of in Ash Ponds 1 & 2 when

needed; in these rare cases the material is transported via a vacuum truck.

Bottom ash generated at Comanche! is hydraulically transported to Ash

Pond 3 (bottom ash pond) that tempprarily stores the ash until it can be

removed. The fly ash/scrubber solid~ generated at Comanche are managed

in a conditioned state and are disposed of in a landfill located on plant

property. The landfill has a clay liner and stormwater is collected in a

retention pond at the disposal facility.

Pond 4 is a polishing pond that Ponds 1- 3 pass through before the water is

discharged in accordance with the ~tate-issued NPDES permit

Pg.1
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 6: PSCo Comanche Station

The ADF Stormwater Retention Pond c~ptures storm water runoff and

associated suspended solids (ash and scrubber solids) from the dry ash

landfill.

Inspections of the ash ponds are conducted daily by plant operators and

chemists for normal operation.

1. Relative to the National Inventory of Dams criteria for High, Significant,

Low or Less-than-Low, please provide the potential hazard rating for each

management unit and indicate who established the rating, what the basis

of the rating is, and what federal, oristate agency regulates the unites). If

the unites) does not having a rating, please note that fact.

All five ponds are incised (below-grade), and none have been rated

by any agency under the National Inventory of Dams criteria, nor

would we expect them to meet any minimum threshold to be rated.

2. What year was each management unit commissioned and expanded?

Ponds 1 - 4 were constructed in 1912.

The ADF Stormwater Retention Pond was constructed in 1987.

3. What materials are temporarily or permanently contained in the unit? Use

the fol/owing categories to respond to this question: (1) fly ash; (2) bottom

ash; (3) boiler slag; (4) flue gas emission control residuals; (5) other. If the

management unit contains more than one type of material, please identify

aI/ that apply. Also, if you identify "other, " please specify the other type of

materials that are temporarily or permanently contained in the unites).

Ponds 1 & 2 containclarifler underflow material and de minimis

quantities of emission control residuals from scrubbers.

Pond 3 temporarily stores bottom ash prior to removal for disposal.

Pond 4 contains process water with only de minimis amounts of

bottom ash or emission control residuals carried over from Ponds 1,

2, or 3.

The ADF Stormwater Retention Pond contains stormwater and small

amounts of sediment, fly ash, bottom ash, or emission control

residuals carried off from the ash disposal facility by surface runoff.

Pg. 2
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 6: PSCo Comanche Station

4. Was the management unites) designed by a Professional Engineer? Is or

was the construction of the was~e management unites) under the

supervision of a Professional Engineer? Is inspection and monitoring of

the safety of the waste management unites) under the supervision of a

Professional Engineer?

Ash ponds 1 - 4 were designed, and construction supervised by a

PE in 1973.

The ADF Stormwater Retention Pond was designed, and

construction supervised by a PE in 1987.

5. When did the company last assess or evaluate the safety (i.e., structural

integrity) of the management u.nft(s)? Briefly describe the credentials of

those conducting the 'structural lh{egrityassessmentlevaluations. 'Identify

actions taken or planned by faGility personnel as a result of these

assessments or evaluations." If corrective actions were taken, briefly

describe the credentials of those performing the corrective actions,

whether they were companyelTJployees or contractors. If the company plans an assessment or evaliJation in the future, when is it expected to

occur?

No records have been located to confirm if the ponds at Comanche

Station have been evaluated for s~ructuralintegrity.

There are no plans currently tb' evaluate the structural integrity of

these ponds in the future, baSed on their design as below-grade,

incised ponds.

6. When did a State or a Federal regulatory official last inspect or evaluate

, the safety (structural integrity) of the management unites)? If you are

aware of a planned state or federal inspection or evaluation in the future,

when is it expected to occur? Please identify the Federal or State

regulatory agency or departinent which conducted or is planning the

inspection or evaluation. Please provide a copy of the most recent official

inspection report or evaluation.

There have been no State or Federal inspections recorded related to

the structural integrity of the Comanche ponds. To the best of our

knowledge there are no inspections pl"anned.

Pg. 3
US EPA Request for Information relating to Surface Impoundments

Date: May 18,2009

Attachment 6: PSCo Comanche Station

7. Have assessments or evaluations, or inspections conducted by State or

Federal regulatory officials conducte,d within the past year uncovered a

safety issue(s) with the management unites), and, if so, describe the

actions that have been or are being !taken to deal with the issue or issues.

Please provide any documentation that you have for these actions.

Please refer to question 6.

8. What is the surface area (acres) and total storage capacity of each of the

management units? What is the volume of materials currently stored in

each of the management unit(s)? Please provide the date that the volume

measurement(s) was taken. Please provide the maximum height of the

management unites). The basis for determining maximum height is

explained later in this Enclosure.

Ponds 1 - 4 are identical in size at 1.6 acres and have a volume of

18,700 cubic yards each. The po~ds are entirely below grade, and

therefore per Enclosure A to EPA's letter, no volume or height

information is reported.

The ADF Storm Water Retention ·Pond capacity is 0.92 acres in size

with a capacity of 12,700 cubic yards. The pond is entirely below

grade, and therefore per Enclosure A to EPA's letter, no volume or

height information is reported.

9. Please provide a brief history of known spills or unpermitted releases from

the unit within the last ten years, wh,ether or not these were reported to

State of federal regulatory agencie$. For purposes of this question,

please include only releases to surface water or to the land (do not include

releases to groundwater).

On April 9, 2007 the pipe from Polishing Pond (#4) going to the river

was hit during an excavation. B~1:ween2000-3000 gallons of process

water was released into an excavation area before the flow was

stopped and the line was patche4. The collected water was pumped

back into the Polishing Pond. We have found no records of any

other known spills or unpermitted releases from the ponds to

surface waters or land during the past 10 years.

10. Please identify all current legal own~rs(s) and operator(s) at the facility.

Pg. 4
·US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 6: PSCo Comanche Station

Generating Unit Nos. 1 and 2 of the Comanche Station are owned by

Public Service Company of Colorado, a subsidiary of Xcel Energy

Inc.

Generating Unit No.3 is operated by Public Service Company of

Colorado. It is jointly owned by PSCo, Intermountain Rural Electric

Association (IREA), and Holy Cross Energy.

Pg. 5
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 6: PSCo Comanche Station

Page intentionally blank

Pg.6
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 7: PSCo Hayden Station

Hayden Station is reporting on the following six surface impoundments:

• High Quality Skimmer Pond

• High Quality Pond

• Intermediate Quality Pond

• Fly Ash Decant Basin

• Common Wet Ash Settling Basin

• Ash Disposal Facility (ADF) Con~ct Storm Water Pond

Note that many, if not all of these surfaqe impoundments are likely beyond

the scope of EPA's information request, given their incised/below-grade

nature, and/or the fact that their primary purpose is not to store or dispose

of coal combustion residuals or byproducts. However, we are including a

description of these surface impoundments for purposes of completeness

and due to the ambiguous nature of EPA's request.

Background:

Hayden Station collects all coal combu$tion residues for dry on-site

disposal. Fly Ash is collected dry and tfansported by truck to an on-site

Ash Disposal Facility (ADF). Bottom ash is dewatered in bins and

transported by truck to an on-site disposal area.

The facility has three above grade process ponds connected in series that

are designed to remove suspended solids and control water chemistry

prior to reuse within the faoility (High Quality Skimmer Pond, High Quality

Pond and the Intermediate Quality Pond). Excess solids that settle out in

the first pond in the series (HQ Skimmer Pond), which may include ash

particles, are periodically dredged, dewatered and then transported to the

on-site ash disposal area.

The facility also has two below grade concrete ash cleanout basins. The

smaller basin (Fly Ash Decant Basin) is used for ash silo load-out cleanup

water and the larger basin (Common Wet Ash Settling Basin) is for storage

if the bottom ash dewatering system fails and other ash dewatering needs.

These basins are normally empty and are cleaned out following each

occurrence.

The facility also has a Contact Storm W;iter Pond that receives stormwater

runoff from the ash disposal area. This'pond water is tested prior to

discharge under a NPDES Permit. The pond is constructed as a basin

following natural contours.

Pg. 1
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009 .

Attachment 7: PSCo Havden Station

Routine visual inspections of these surface impoundments are conducted

by plant personnel.

1. Relative to the National Inventory of Dams criteria for High, Significant,

Low or Less-than-Low, please provide the potential hazard rating for each

management unit and indicate who established the rating, what the basis

of the rating is, and what federal, or state agency regulates the unit(s). If

the unit(s) does not having a rating, please note that fact.

The Intermediate Quality Pond is listed. on the NID and rated as a

Low Hazard Dam.

The three process water ponds (High Quality Skimmer Pond, High

Quality Pond and the lntermediate Quality Pond) share a common

dam around them and are classified on the State of Colorado,

Division of Water Resources - Dam Safety Branch's inspection forms

as Low Hazard. The State inspects this dam every 6 years.

The two concrete cleanout basins (Fly Ash Decant Basin and the

Common Wet Asf:l Settling Basill)a9d the Contact Storm Water Pond

at the ash disposal area have' not been classified, nor would we

. expect them to meet the minimum threshold for any rating.

2. What year was each management unit commissioned and expanded?

The High Quality Skimmer Pond, High Quality Pond and the

Intermediate Quality Pond were commissioned in 1975.

The Fly Ash Decant Basin and the Common Wet Ash Settling Basin

were commissioned in 1992.

The contact storm water pond at the ADF was commissioned in 1983.

This pond is formed by the working face of the ash disposal cell and

the adjacent native hillside. Consequently, the configuration of this

pond is modified both vertically and horizontally during the course of

development of the ash disposal area.

3. What materials are temporarily or permanently contained in the unit? Use

the fol/owing categories to respCnd to this question: (1) fly ash; (2) bottom

ash; (3) boiler slag; (4) flue gas emission control residuals; (5) other. If the

management unit contains mortJ than one tYpe of material, please identify

al/ that apply. Also, if you identify "other," please specify the other type of

Pg. 2
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 7: PSCo Havden Station

materials that are temporarily or permanently contained in the unites).

Small amounts of fly ash, bottom ash, and flue gas emission control

residues are temporarily deposit~' in the first pond (High Quality

Skimmer Pond) in the series. This pond is periodically dredged and

any material removed is dewater~d and sent for disposal.

Some fly ash, bottom ash, and flue gas emission control residues

may move through the under drains to the High Quality Pond.

The Intermediate Quality Pond may contain water that has mixed

with fly ash, bottom ash, and flue gas emission control residues in

the two previous ponds.

The Fly Ash Decant ~,asil1m~y contain fly ash, bottom ash, and flue

gas emission control re~id~~s.

The Common Wet 'Ash Settling Basin may contain fly ash, bottom

ash, and flue gas emission, ~ontrol residues.

'I . .' ., ... <

The Contact Storm Water'Pond'at the ,a~hdisposal area may contain

fly ash, bottom ash, and flue gas emission control residues.

4. Was the management unites) designed by a Professional Engineer? Is or

was'the construction of the waste management unites) under the

supervision of a Professional Engineer? Is inspection and monitoring of

the safety of the waste management unites) under the supervision of a

Professional Engineer?

The High Quality Skimmer Pond, High Quality Pond and the

Intermediate Quality Pond were designed by a Professional Engineer

(PE). A PE supervised the construction of these three ponds.

A PE Dam Engineer from the State of Colorado, Division of Water

Resources - Dam Safety Branch, inspects the High Quality Skimmer

Pond, High Quality Pond and the Intermediate Quality Pond Dam

every 6 years.

A PE did not design or oversee the construction of the Fly Ash

Decant Basin and the Common Wet Ash Settling Basin.

A PE did not design or oversee the construction of the Contact

Storm Water Pond at the ash disposal area.

Pg. ~
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 7: PSCo Havden Station

5. When did the company last assess or evaluate the safety (i.e., structural

integrity) of the management unit(s)? Briefly describe the credentials of

those conducting the structural integrity assessment/evaluations. Identify

actions taken or planned by facility personnel as a result of these .

assessments or evaluations. If corrective actions were taken, briefly

describe the credentials of those performing the corrective actions,

whether they were company employees or contractors. If the company

plans an assessment or evaluation in the future, when is it expected to

occur?

As. noted in the response to Question 4, the High Quality Skimmer

Pond, High Quality Pond and the Intermediate Quality Pond are

regularly inspected by a dam safety engineer from the State of

Colorado. These structures are also subject to routine operational

inspections by plant staff to identify issues that might develop

between State inspections. We would not normally perform an

independent and redundant sJructuraJ safety or integrity inspection

absent a specific concern.

The Company has not performed a structural safety inspection of the

below-grade Fly Ash Decant Basin, the Common Wet Ash Settling

Basin, or the Ash Contact Storm Water Pond. There are no plans to

evaluate the structural integrity of these ponds in the future.

6. When did a State or a Federal regulatory official last inspect or evaluate

the safety (structural integrity) of the management unites)? If you are

aware of a planned state or federal inspection or evaluation in the future,

when is it expected to occur? Please identify the Federal or State

regulatory agency or department which conducted or is planning the

inspection or evaluation. Please provide a copy of the most recent official

inspection report or evaluation.

The State of Colorado, Division of Water Resources - Dam Safety

Branch inspected the three process water ponds (High Quality

Skimmer Pond, High Quality Pond and the Intermediate Quality .

Pond) on May 9,2007. The Dam Engineer is a PE. The State of

Colorado Inspection Report is attached.

There have been no other State or Federal inspections recorded

related to the structural integrity of these or the other ponds. To the

best of our knowledge there are no future inspections planned at

Pg.4
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 7: PSCo Havden Station

this time, other than the six-year recurring Colorado State inspection noted above.

7. Have assessments or evaluations, or inspections conducted by State or

Federal regulatory officials conducted within the past year uncovered a

safety issuers) with the management unites), and, if so, describe the

actions that have been or are being taken to deal with the issue or issues.

Please provide any documentation that you have for these actions.

There were only minor issues noted on the inspection report

including rodent control, '{egetatiQn management and crest grading.

Corrective actions have been' completed. See attached Weed

Control PUl;'chase :•.Order1'#"269792, , :'Crest Grading Work Order # •

2973887..

8. What is the surface area (adres). and tdtal storage capacity of each of the

management units? What.',' is',' the'I volume of mat/3ria/sburtently stored in

each of the managemeht unit(s)? Please provide the' date that the volume

measurement(s) was taken. Please provide the maximum height of the

management unites). The ba~is for determining maximum height is

explained later in this Enclo'Stir13., .

The High Quality Skimmer por-d has a design maximum surface area

under 1.0 acre and 8,872 cubic 'yards of storage. The embankment is

approximately 19 ft. high from toe to crest. As of May 7, 2009 a

visual estimate of the volume of ash or other solids in this pond is

about 3,000 cubic yards. This pond is' currently being dewatered and

should be cleaned out this summer.

The High Quality pond has a'design maximum surface area under 4.5

acres and 65,000 cubic yards of storage. The embankment is

approximately 15 ft. high from toe to crest .. As of May 7, 2009 a

visual estimate of the volum.e of a$h or other solids in this pond is

about 1,000 cubic yards. This pond contains about 7,500 cubic yards

of water, is currently being dewatered and should be cleaned out this

summer.

The Intermediate Quality pond has a design maximum surface area

under 20 acres with 442,000 cubic yards of water storage. The pond

is normally maintained at or near full capacity. The embankment is

approximately 22 ft. high from toe to crest. We do not have current

information on the volume of ash or other solids in this pond, since

the pond is intended for process water storage and treatment and

Pg. 5
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 7: PSCo Havden Station

does not receive significant volumes of solids. The pond water level

is typically maintained at or near capacity.

The Fly Ash Decant Basin has a design maximum surface area under

. 0.006 acres, and a capacity of 64.5 cubic yards. The pond is entirely

below grade, and therefore per Enclosure A to EPA's letter, no

volume or height information is repQrted.

The Common Wet Ash Settling Basin has a design maximum surface

area under 0.09 acres, and a capacity of 474 cubic yards. The pond

is entirely below grade, and therefore per Enclosure A to EPA's

letter, no volume or height information is reported.

The Contact Storm Water Pond at the ash disposal area has a

surface area of under 0.75 acres, and a capacity of approximately

5,900 cubic yards. The pond is entirely beJow grade, and therefore

per Enclosure A to EPA's lett$r, no volume or height information is

reported.

9. Please provide a brief history of known spills or unpermitted releases from

the unit within the last ten years, whether or not these were reported to

State of federal regulatory agencies. For purposes of this question,

please include only releases to surface water or to the land (do not include

releases to groundwatel).

We have found no record of known spills or un-permitted releases

from the units to surface water or to the land within the past 10

years.

10. Please identify all current legal owners(s) and operator(s) at the facility.

The Hayden Station is operat~d by Public Service Company of

Colorado, which is a subsidiary of Xcel Energy Inc. It is jointly

owned by PSCo, PacifiCorp, and Salt River Project.

Pg. 6
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009 .

Attachment 8: PSCo Pawnee Station

Pawnee Station'is reporting on the fQllowing six surface impoundments

and one ash disposal facility:

• New BO~Qm;Ash Water Recove'iy ·Pond

• Bottom Ash :Oisposal Pond

• Ash Water Recovery Pohd

• Intermediate Quality (IQ) Water Pond

• Evaporative Pond B

• Evaporative Pond C

• Ash Disposal Facility (ADF)

Note that many, if not all of these surface impoundments and the landfill

are likely beyond the scope of EPA'sinfprmation request, given their

incised/below-grade rlature, and/or.the fact tha,ttheir: primary purpose is

not to.store or dispose of coal combustion-residuals or byproducts.

However, we are including' a'description of them all-for purposes of

completeness and due to the ambiguous nature of EPA's request.

Background: , i

t' " ..

Pawnee Sta.tion is a zero discha~ge' facility. Fly ash and bottom ash are

both coJlected on a,dry basis and are "mar:'ketedfor a variety of beneficial

uses, including concrete. A minor fraction of ash that is not sui,table for

utilization is disposed of in an on-site la..-dfill that is constructed entirely

below grade. This landfill also receives 'raw water treatment system

clarifier residuals that are transported by.truck.

In 2002, the plant installed a drag-chain to mechanically remove and

dewater bottom ash prior to loading on a truck for uti.lization or disposal in

the on site dry landfill. Prior to this conversion, bottom ash was sluiced to

lined settling ponds. From there it was periodically dredged and dewatered

for disposal in the on-site dry landfill.

The following ponds may come in con~ct with or have the potential to

contain a small amount of bottom ash fines: "New" Bottom Ash Water

Recovery Pond, Bottom Ash Disposal Pond, Ash Water Recovery Pond,

Intermediate Quality (IQ) Pond, Evaporative Pond B, and Evaporative Pond

C.

1. The "New" Bottom Ash.Water Recovery Pond is used as a holding

basin for make up water to the boiler bottom ash water system.

Although the primary function of the pond is a reservoir for the boiler

bottom ash water system, it contains a small portion of bottom ash

Pg. 1
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 8: PSCo Pawnee Station

fines, as the water is re-circulated through the boiler bottom ash

water system.

2. The Bottom Ash Disposal Pond is no longer in service. This pond

was a settling pond in which sluiced bottom ash settled out and the

water was recovered for re-circulation. After the solids settled in the

pond, the overflow drained into the Ash Water Recovery Pond. This

pond still contains some residual bottom ash and occasionally

receives direct precipitation

3. The Ash Water Recovery Pond is no longer in service. It served as a

re-circulation basin for the boiler bottom ash water system after

grinding and sluicing of bottom ash. This is a below grade pond that

still contains some residual bottom ash and occasionally receives

direct precipitation.

4. The Intermediate Quality (IQ) Water Pond is used to store storm

water runoff, high quality pondoverflow, and miscellaneous plant

drains. When water resource~ are low, the pond makeup can be

supplemented using the water from the boiler bottom ash water

system, therefore the pond potentially contains a small amount of

bottom ash.

5. Evaporative Ponds Band C are used to collect wastewater from the

brine concentrators and overflow from the IQ pond. The primary

function of the ponds is to collect and evaporate wastewater from

the brine concentrators. A third, idle evaporative pond exists atthe

site (Pond A) and had the same function as Ponds Band C when it

was in use. However, it has been empty and out of service since

about 2004.

6. Pawnee has a landfill, which in past operations has been used to

dispose of fly ash and bottom ash (hauled by truck), and slurry

produced from the water treatment clarifier, which is also

transported by truck. Currently, the majority of bottom ash and fly

ash are being marketed for beneficial reuse and a very limited

amount is being disposed in the landfill. The landfill continues to

accept slurry waste from the clarifier. The landfill was formed by an

excavation and is fully below grade.

Routine visual inspections of the ponds and landfill are conducted by

plant or contractor personnel.

Pg.2
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 8: PSCo Pawnee Station

1. Relative to the National Inventory of Dams criteria for High, Significant,

Low or Less-than-Low, please provide the potential hazard rating for each

management unit and indicate who established the rating, what the basis

of the rating is, and what federal, or state agency regulates the unit(s). If

the unit(s) does not having a rating, please note that fact.

The Intermediate Quality Pond and the Evaporation Ponds are listed

on the NID and rated as Low Hazard Dams.

The Colorado State Engineers O~ce, Divisions of Water Resources,

regulates the "New" Bottom Ash Water Recovery Pond, IQ pond, and

Evaporative ponds Band C. The State Engineer has classified the IQ

Pond and Evaporative Ponds Band C as Class 3 dams. The

Engineer's Office has not classified the "New" Bottom Ash Water

Recovery Pond or the Bottom Ash Disposal Pond.

The Ash Water Recovery p'Qn!J and Fly Ash Landfill are below grade,

and have not been rated~by '~ny agency under the National Inventory

of Dams, nor do we believe they would meet the minimum threshold

for any rating.

2. What year was each management unit commissioned and expanded?

The Bottom Ash Disposal Pond and Ash Water Recovery Pond were

commissioned in 1980; use was discontinued in 2002.

The IQ Pond and Evaporative Ponds Band C were commis~ioned in

1980.

The "New" Bottom Ash Water Recovery Pond was constructed and

commissioned in 2005.

The Landfill was constructed in the late 19705 and placed into

service in 1980.

3. What materials are temporarily or permanently contained in the unit? Use

the following categories to respond to this question: (1) fly ash; (2) bottom

ash; (3) boiler slag; .(4) flue gas emission control residuals; (5) other. If the

management unit contains more than one type of material, please identify

all that apply. Also, if you identify "other, " please specify the other type of

materials that are temporarily or permanently contained in the unit(s).

Pg. 3
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009 .

Attachment 8: PSCo Pawnee Station

Both the Bottom Ash Disposal Pond and Ash Water Recovery Pond

contain bottom ash from prior operations. The amount of water

retained in these ponds from precipitation is insignificant and,

typically evaporates quickly due to the arid climate. Both ponds are

no longer in service.

The "New" Bottom Ash Water Recovery Pond contains a small

amount of bottom ash within the process water managed in this

pond.

The IQ pond contains a small,amount of bottom ash within the

process water managed in this pond.

Evaporative Ponds Band C contain plant process wastewater and

solids from the wastewater evaporation. Th~se ponds also have the

remote possibility of containing bottom ash fines from the IQ pond

overflow .

. The Landfill contains fly ash, bottom ash, and lime slurry from the

water treatment process.

4. Was the management unites) designed by a Professional Engineer? Is or

, was the construction of the wa$te management unites) under the

supervision of a Professional Engineer? Is inspection and monitoring of

the safety of the waste management unites) under the supervision of a

Professional Engineer?

A Professional Engineer designed all ponds and the landfill. Plant

construction records do not indicate that a Professional Engineer

supervised construction of the original ponds.

The "New" Bottom Ash Water Recovery Pond, IQ Pond, and

Evaporative Ponds Band C are under the jurisdiction of the

Colorado State Engineer.

5. When did the company last assess or evaluate the safety (i.e., structural

integrity) of the management unit(s)? Briefly describe the credentials of

those conducting the structural integrity assessment/evaluations. Identify

actions taken or planned by facility personnel as a result of these

assessments or evaluations. Ifcorrective actions were taken, briefly

describe the credentials of those performing the corrective actions,

whether they were company employees or contractors. If the company

plans an assessment or evaluation in the future, when is it expected to

Pg.4
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 8: PSCo Pawnee Station

occur?

No record of any structural integrity assessment of the ponds by

Company personnel has been found.

Structures classified as dams are regularly inspected by a Dam

Safety Engineer from the State of Colorado (see response to

Question 6 below). We would not normally perform an independent

and redundant structural safety or integrity inspection absent a

specific concern.

There are no plans to evaluate the structural integrity of ponds not

classified as dams.

6. When did a State or a Federal re,gulatory official last inspect or evaluate

the. safety (structural infegritY) of the management unit(s)? If you are

aware of a planned state or federal inspection or evaluation in the future,

when is it expected to occur? Please identify the Federal or State

regulatory agency or depafttfiem whichconducted or is planning the

inspection or evaluation. Please provide a copy of the most recent official

inspection report or evaluat~on.

The State Engineer conducts periOdic inspections of the ponds classified as dams.

The last safety evaluation for the IQ pond was conducted in 2002 by

the Colorado State Engineer. The inspector indicated that this pond

should be classified as a Class ,4 dam, but we have received no

documentation reclassifying this from a Class 3 pond.

The Colorado State.Engineer inspected evaporative ponds A, Band

C in December of 2008. At the fifn~ of the inspection repairs were

being conducted on the liner for C Pond as noted in the report.

The Colorado State Engineer has not inspected the "New" Bottom

Ash Water Recovery Pond. Based on the normal interval of State

inspections, we anticipate the pond will undergo a safety inspection

by the State Engineer in or ·around 2010.

7. Have assessments or evaluations, or inspections conducted by State or

Federal regulatory officials conducted within the past year uncovered a

safety issuers) wIth the management unites), and, if so, describe the

actions that have been or are being taken to deal with the issue or issues.

Pg. 5
US EPA Request for Information relating to Suliace Impoundments

Date: May 18, 2009

Attachment 8: PSCo Pawnee Station

Please provide any documentation that you have for these actions.

During the inspection of Evaporative Ponds A, Band C in December

of 2008, three issues were identified:

1) "No gage rods" was noted in the report. Gage rods were

actually present in Ponds Band C, but new rods have sin"ce

been installed in these ponds. Pond A is empty and out of

service, so no gage rod is necessary.

2) Erosion was noted on the access road between Ponds A and

B. The eroded areas have since been repaired.

3) Damage was noted on to the liner of Pond C. See the attached

Work Order # 2962135 documenting the repair to correct this

damage.

8. What is the surface area (acres) and total storage capacity of each of the

management units? What is the volume of materials currently stored in

each of the management unites)? Please provide the date that the volume

measurement(s) was taken. Please provide the maximum height of the

management unites). The basis for determining maximum height is

explained later in this Enclosure.

The "New" Bottom Ash Water Recovery Pond size is 6 acres with a

total storage capacity of 83,900 cubic yards. Current volume is

estimated as 52,400 cubic yards as measured on May 3, 2009, and

primarily consists of water with minor amounts of solid material.

Maximum height is 16 ft.

The Bottom Ash Disposal Pond size is 13 acres, and total storage

capacity is 403,000 cubic yards. Current volume is estimated at

121,000 cubic yards, with estimations based on observation of solids

accumulated on May 3, 2009.. Maximum height is 10 ft.

The Ash Water Recovery Pond size is 1 acre, and total storage

capacity is.8,100 cubic yards .. The pond is entirely below grade, and

therefore per Enclosure A to EPA's letter, no volume or height

information is reported.

The IQ Pond size is 3.5 acres with a total storage of 77,400 cubic

yards. Current volume as measured on May 3,2009 is 35,500 cubic

,yards, and primarily consists of water with minor amounts of solid

material. The maximum height is 21 ft.

Pg.6
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 8: PSCo Pawnee Station

Evaporative Pond B size is 14.8 a~reswith a total storage of 222,200

cubic yards. Volume as measured on May 3,2009 is 114,200 cubic

yards, and primarily consists of water with minor amounts of solid

material. The maximum height is 13 ft.

Evaporative Pond C size is 10.5 acres with a total storage of 154,900

cubic yards. Volume as measured on May 3, 2009 is 87,600 cubic

yards, and primarily consists of water with minor amounts of solid

material. The maximum height is 13 ft.

The Landfill size is 34 acres with a total storage capacity of 2,176,400

cubic yards. The landfill is entirely below grade, and therefore, per

Enclosure A to EPA's letter,no volume or height information is

reported. I

9. Please provide a brief history of known spills or unpermitted releases from

the unit within the last ten yea~,'Whethei or not these were reported to

State of federal regulatory agenCies. 'For purposes of this question,

please include only releases to 'sUrface water or to theland(do not include

releases to groundwater). "

We have found no record of known spills or un-permitted releases

from the management unitS to surface water or to the land within the

past 10 years.

10. Please identify all current legal owners(s) and operator(s) at the facility.

Pawnee Station is owned by Public Service Company of Colorado, a

subsidiary of Xcel Energy.

Pg.7
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 8: PSCo Pawnee Station

Page intentionally blank

Pg. 8
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 9: PSCd Valmont Station

Valmont Station is reporting on the following three surface impoundments:

• East Ash Settling Pond

• West Ash Settling Pond

• Coal Pile Stormwater Runoff Pond

Note that many, if not all of these surfaqe impoundments are likely beyond

the scope of EPA's information request, given their incised/below-grade

nature, and/or the fact that their primary purpose is not to store or dispose

of coal combustion residuals or byproducts. However, we are including a

description of these surface impoundments for purposes of completeness

and due to the ambiguous nature of EPA's request

Background:

The Valmont Generating Station collects all coal combustion by-products

for off-site utilization or on-site disposaJ in a State approved dry ash

landfill. Fly ash is collected dry. Bottom ash is hydraulically conveyed to

two ash settling ponds which are excavated bi-annually and the ash either

utilized or disposed. The outfall of the ash disposal ponds is regulated

under the site NPDES permit and discharges to the plant cooling water

reservoir system. The ponds are not permanent ash disposal ponds but

rather provide settling and temporary storage of bottom ash. Only one of

these ponds is typically active and used at anyone time. Operating

practice is to clean out and switch the active pond every year.

The Coal Pile Stormwater Runoff Pond has the capability of receiving

washdown from the paved area around the ash storage silo.

Valmont Station has three large reservoirs on site. These are used for raw

water storage and plant water cooling/recirculation.

The day-to-day pond operations,are monitored by the Plant Chemist,

according to the requirements of the NPDES permit.

1. Relative to the National Inventory of Dams criteria for High, Significant,

Low or Less-than-Low, please provide the potential hazard rating for each

management unit and indicate who established the rating, what the basis

of the rating is, and what federal, orstate agency regulates the unites). If

the unites) does not having a rating, please note that fact.

The Ash Settling and Stormwater Runoff ponds are incised (belowgrade). Neither has been rated by any agency under the National

Pg. 1
US EPA Request for Information relating to Surace Impoundments

Date: May 18, 2009

Attachment 9: PSCo Valmont Station

Inventory of Dams (NID), nor would we expect them to meet the

minimum threshold for any rating.

2. What year was each management unit commissioned and expanded?

Both Ash Settling Ponds were built in 1964 and the Coal Pile

Stormwater Runoff Pond was built in 1993.

3. What materials are temporarily or permanently contained in the unit? Use

the following categories to respond to this question: (1) fly ash; (2) bottom

ash; (3) boiler slag; (4) flue gas emission control residuals; (5) other. If the

management unit contains more than one type of material, please identify

all that apply. Also, if you identify "other, " please specify the. other type of

materials that are temporarily or permanently contained in the unites).

The East and West Ash Settling Ponds primarily contain bottom ash

but may contain some de minimis amounts of fly ash and/or

emission control residue.

The Coal Pile Stormwater Runoff Pond primarily contains coal fines,

but may also contain some de minim.is amounts of fly ash and/or

emission control residue from washdown operations.

4. Was the management unites) designed by a Professional Engineer? Is or

was the construction of the waste management unites) under the

supervision of a Professional Engineer? Is inspection and monitoring of

the safety of the waste management unites) under the supervision of a

Professional Engineer?

The ponds were designed by Professional Engineers. We were

unable to locate documentation to confirm whether construction was

overseen by a Professional Engineer.

5. When did the company last assess or evaluate the safety (Le., structural

integrity) of the management unit(s)? Briefly describe the credentials of

those conducting the structural integrity assessment/evaluations. Identify

actions taken or planned by facility personnel as a result of these

assessments or evaluations. If corrective actions were taken, briefly

describe'the credentials of those performing the corrective actions,

whether they were company employees or contractors. If the company

plans an assessment or evaluation in the future, when is it expected to

occu~ .

Pg, .2
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 9: PSCo Valmont Station

PSCo has not conducted structural integrity evaluations of either the

Ash Settling Ponds or the Coal Pile Stormwater Runoff Ponds

because of their small'size and at grade construction.

6. When did a State or a Federal regulatory official last inspect or evaluate

the safety (structural integrity) of the management unit(s)? If you are

aware of a planned state or federal inspection or evaluation in the future,

when is it expected to occur? Please identify the Federal or State

regulatory agency or department which con.ducted or is planning the

inspection or evaluation. Please provide a copy of the most recent official

inspection report or evaluation.

There have been no state or Federal inspections recorded related to

the structural integrity of these management units. To the best of

our knowledge, there are n9 state or federal inspections planned for

these manageme9t uni~ ... ,

7. Have assessments or evaluations, or inspections conducted by State or

Federal regulatory officials pon4l.{rfed within the past year uncovered a

safety issue(s) with the man~,Qer!1(!JfJrunit(s),and, if so, describe the

actions that have been or are being taken to deal with the issue or issues.

Please provide any documimtatton that you have for these actions.

Not applicable - refer to item 6.

8. What is the surface area (acres) and total storage capacity of each of the

management units? What is the volume of materials currently stored in

each of the management unites)? Please provide the date that the volume

measurement(s) was taken. Please provide the maximum height of the

management unites). The basis for determining maximum height is

explained later in this Enclosure.

The Ash Settling Ponds are each approximately 1 acre in size, with a

capacity of about 26,000 cubic yards. Both are entirely below grade,

and therefore, per Enclosure A to EPA's letter, no volume or height

information is reported.

The Coal Pile Stormwater Runoff Pond is approximately 0.14 acres in

size, and has a capacity of about 670 cubic yards. The pond is

entirely below grade, and therefore, per Enclosure A to EPA's letter,

no volume or height information is reported.

Pg. 3
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

Attachment 9: PSCo Valmont Station

9. Please provide a brief history of known spills or unpermitted releases from

the unit within the last ten yeats, whether or not these were reported to

State of federal regulatory agencies. For purposes of this question,

please include only releases to surface water or to the land (do not include

releases to groundwater}.

There was one recorded spill from the West Ash Settling Pond on

February 14, 2008 that was reported to the State of Colorado and the

National Response Center (NRC). About 25 cubic yards of bottom

ash slurry was released into the plant cooling water reservoirs. A

vacuum truck was used to recover the bottom ash.

We have found no record of other known spills or unpermitted

releases from.. any of the units to surface water or land within the last

ten years.

10. Please identify all current legal owners(s) and operator(s) at the facility.

The Valmont Station is owned by Public Service Company of

Colorado, a subsidiary of Xcel Energy Inc.

Pg.4
(l Xcel Energy· RESPONSIBLE BY NAT IEOctober 12, 2009

Mr. Richard Kinch

US Environmental Protection Agency (5306P)

1200 Pennsylvania Avenue, NW

Washington, DC 20460

414 Nicollet Mall

Minneapolis, MN 55401

1-800-895-4999

xcelenergy.com

Re: Summary Database Results Errors - Request for Information relating to

Surface Impoundments Under 104 (e) of the Comprehensive

Environmental Response, Compensation, and Liability Act, 42 U.S.C.

9604(e).

Dear Mr. Kinch:

On May 18, 2009 we submitted responses to the US Environmental Protection

Agency (EPA) "Request for Information" received May 4, 2009 pertaining to

surface impoundments used to manage coal combustion residuals or byproducts

at the following operating companies:

• Public Service Company of Colorado (PSCo), a Colorado corporation;

• Northern States Power Company of Minnesota (NSP-M), a Minnesota

corporation, and:

• Northern States Power Company of Wisconsin (NSP-W), a Wisconsin

corporation

EPA subsequently released a summary of the submitted i[1formation to third

parties per a FOIA request and has now placed that summary information

(Database Results - PDF) on their website at:

http://www.epa.gov/epawaste/nonhaz/industrial/special/fossil/survevs/index.htm

A review of the summary table has indicated that it contains several errors, which

are inconsistent with the information we provided on May 18th. For your

convenience, the inconsistencies are identified separately by operating company

in the three attachments.
US EPA Request for Information relating to Surface Impoundments

Date: May 18, 2009

To ensure that correct information is utilized by the EPA, by State agencies, and

is made available to the public, we request that the database be updated to

reflect the correct information in an expeditious manner. We further request that

after correctioh of the EPA database and summary posted on the Agency's web

site, any organizations or persons that received incorrect information under a

FOIA request be notifi~d that corrected information is available. Please direct

any questions concerning this submittal to my attention at the address listed

below.

55401

10-/2,- OC1

Date'

Sincerely,

- ~Cs~ ..- I

j

Terry E. Coss, PE

Environmental Director

Xcel Energy

414 Nicollet Mall, Minneapolis, MN

(612) 330-5596

Attachment 1: Public Service Company of Colorado (PSCo)

Attachment 2: Northerh States Power Company of Minnesota (NSP-M)

Attachment 3: Northern States Power Company of Wisconsin (NSP-W)

Pg. 2
Summary Database Results Errors - US EPA Request for Information relating to Surface

Impoundments

Date: October 5, 2009

Attachment 1·: Public Service Company of Colorado (PSCo)

The following errors were identified in the summary Database Results table

pertaining to PSCo facilities:

• Cherokee Station

o The Emergency Spill Pond storage capacity should be 5 acre-ft

(7,700 CY), not 0 acre-ft as shown.

• Hayden Station

o The High Quality pond capacity should be 40 acre-ft (65,000 CY),

not 1 acre-ft as shown.

• Pawnee Station -

o Corrective measures were implemented for the two evaporation

ponds, as evidenced by our text and the attachments sent in the

initial response. Therefore, Column 7 should read "Yes", not "No"

as shown.

o The storage capacity values for the following ponds (listed in the

order shown) are incorrect. It appears that the "current volume"

information submitted was used (incorrectly) to determine the

volumes shown, instead of using the "total storage capacity"

information also requested and provided in our response. The

correct pond capacity numbers that should actually be reported are:

• Evaporation Pond C - 96 acre-ft (154,900 CY)

• New Bottom Ash Water Recovery Pond - 52 acre-ft (83,900

CY)

• Bottom Ash Disposal Pond - 250 acre-ft (403,000 CY)

• Evaporation Pond B - 138 acre-ft (222,200 CY)

• Intermediate Quality (IQ) Water Pond - 48 acre-ft (77,400

CY)

Pg. 1
Summary Database Results Errors - US EPA Request for Information relating to Surface

Impoundments

Date: October 5, 2009

Attachment 2: Northern States Power of Minnesota (NSP-M)

The following errors were identified in the summary Database Results table

pertaining to NSP-M facilities:

• Minnesota Valley Generating Plant

o Ponds 1 and 2 have a maximum storage volume of 9 acre-ft.

instead of 7 acre-ft. shown on column 8.

• Sherburne County Generating Plant

o Pond No.3 (North portion) was put into service in 2004 instead of

1975 as shown in Column 2.

Pg. 1
Summary Database Results Errors - US EPA Request for Information relating to Surface

Impoundments

Date: October 5, 2009

Attachment 3: Northern States Power Company of Wisconsin (NSP-W)

The following errors were identified in the summary Database Results table

pertaining to NSP-W facilities:

o No errors were noted.

Pg. 1