Dams and Impoundments

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Dams and Impoundments
2010 Industry Training Workshop
Jim Kline
DEP- Bureau of Oil and Gas Management
Objectives:
•
Typical Scenarios
•
Worksheet for Permitting of Marcellus Shale Pits and Dams
•
What permits (if any) might be needed
•
Construction Standards for Impoundments
•
Groundwater Monitoring
•
Current impoundment trends
Typical Scenarios
• Dams on a watercourse
• Dams not on a watercourse
Dams on a Watercourse
Greater than 100 acre
drainage area, OR
Greater than 15’ maximum depth, OR
Greater than 50 acre-feet maximum storage
Drainage area
The drainage area is the total surface area
upstream of a point on a stream, where
the water from rain or snowmelt which is
not absorbed into the ground flows over
the ground surface back into the stream to
finally reach that point on the stream.
Drainage area
What the heck is an Acre Foot?
A measurement associated with a larger volume,
in this case water storage. It is the amount of
water required to cover an acre one foot deep.
An acre foot is equivalent to 325,851 gallons of
water
50 acre feet is equal to 16,292,550 gallons of
water
MAXIMUM DEPTH
Dmax > 15 ft
The bottom of the Pit or
Impoundment must be constructed
at least 20” above the seasonal
high groundwater table.
(ref Ch 78.56 (a) (4) (iii))
Dams on a Watercourse
Greater than 100 acre
drainage area
OR
Greater than 15’ maximum depth
OR
Greater than 50 acre-feet maximum storage
If this is the scenario, then a Dam Safety Permit is
required from DEP’s Division of Dam Safety
Dams not on a watercourse
Greater than 15’ maximum depth
AND
Greater than 50 acre-feet maximum
storage
Worksheet for
Permitting of
Marcellus Shale Pits
and Dams
Worksheet for Permitting of Marcellus
Shale Pits and Dams
1. Fresh or frac water impoundment pits or dams at a well
location must meet the requirements of PA Code Chapter
78.56 – 78.63 and the Design, Construction and
Maintenance Standards for Pits and Dam Embankments
Associated with Impoundments for Oil and Gas Wells. Plans
must include an acknowledgement that these pits and
impoundment dams will meet the standards. Proceed to
Section 6 and Section 8 and submit to the appropriate
Department Regional Oil and Gas Program Office.
Worksheet for Permitting of Marcellus
Shale Pits and Dams

2.
On-stream intake dams. (Dams/weirs constructed for
water withdrawal from streams. Height and storage are
typically minimal.)

2.A A dam/weir will be constructed on-stream solely for the
purpose of water withdrawals:

No: Proceed to Section 3 or Section 4 as appropriate.

Yes: Answer the following questions:
Worksheet for Permitting of
Marcellus Shale Pits and Dams

Is maximum depth greater than 15 feet?
Yes No

Is maximum storage volume greater than 50 acre-feet? Yes No

Is contributory drainage area greater than 100 acres? Yes No

If the answer to all three of these questions is no, an Environmental
Assessment approval is required from the Department’s Dam Safety
Program.
Please submit form 3140-PM-WE0002, Environmental Assessment
Information Sheet and information required on that form’s checklist to the
Department’s Dam Safety Office. Any excavation of the stream, wetland or
floodway upstream of this intake dam to expand storage volume will require
a Water Obstruction and Encroachment Permit from the appropriate
Department Regional Office.
Worksheet for Permitting of
Marcellus Shale Pits and Dams

If the answer to any one of these questions is yes, a Dam Permit
may be required from the Department’s Dam Safety Program.
Answer the following questions:

Is height of dam/weir above streambed elevation greater than 3.0
feet? Yes
No

Is width of stream at the dam site greater than 50 feet? Yes No

Is this stream a wild trout stream designated by the PA Fish and
Boat Commission?
Yes
No
Worksheet for Permitting of
Marcellus Shale Pits and Dams

If the answer to all three of these questions is no, the Dam Permit
for this dam is waived pursuant to §105.12(a)(1) of the Department’s
regulations. Contact the Department’s Dam Safety Program for
information requirements necessary for adding to Pennsylvania’s
Dam Inventory.

If the answer to any one of these questions is yes, a Dam Permit is
required from the Department’s Dam Safety Program. Please
complete form 3140-PM-WE0001, “Application for a Dam Permit”,
and information required on that form’s checklist to the Department’s
Dam Safety Office. Utilize the Design, Construction and
Maintenance Standards for Pits and Dam Embankments Associated
with Impoundments for Oil and Gas Wells to develop plans and
specifications.
Worksheet for Permitting of
Marcellus Shale Pits and Dams

3.
Centralized fresh water impoundments.

3.A A dam embankment will be constructed for the
purpose of storing fresh water for the drilling or
fracing at more than one well location:

No: Fresh water will be impounded in a pit. Proceed to
Section 7 for additional information requirements.

Yes: Provide the following depth and volume information
and proceed to Section 3.B.
Worksheet for Permitting of
Marcellus Shale Pits and Dams

Maximum depth of water that could be impounded by the earthfill dam.
See Exhibit 1.
Feet.
(Measure from the inside toe-of-slope of dam to top-of-dam embankment).

Maximum storage volume of water that could be impounded by the earthfill
dam. See Exhibit 1.
acre-feet
(Measure from the inside toe-of-slope of dam to top-of-dam embankment).

Drainage area to the earthfill dam, if located on-stream, then proceed to
Section 3.B.
Acres.

If located off-stream, proceed to Section 3.C.
Worksheet for Permitting of
Marcellus Shale Pits and Dams

3.B If the dam embankment used to impound fresh water is
located on a watercourse, complete the following:

Is maximum depth greater than 15 feet?

Is maximum storage volume greater than 50 acre-feet? Yes No

Is contributory drainage area greater than 100 acres? Yes No
Yes
No
Worksheet for Permitting of
Marcellus Shale Pits and Dams

If the answer to any one of these questions is yes, a Dam Permit is
required from the Department’s Dam Safety Program. Please
submit form 3140-PM-WE0001, “Application for a Dam Permit”, and
information required on that form’s checklist to the Department’s
Dam Safety Office.
Worksheet for Permitting of
Marcellus Shale Pits and Dams

If the answer to all three of these questions is no, an
Environmental Assessment approval is required from the
Department’s Dam Safety Program. Please submit form
3140-PM-WE002, Environmental Assessment
Information and information required on that form’s
checklist to the Department’s Dam Safety Office. Any
excavation of the stream, wetland or floodway upstream
of this intake dam to expand storage volume will require
a Water Obstruction and Encroachment Permit from the
appropriate Department Regional Office.
Worksheet for Permitting of
Marcellus Shale Pits and Dams

3.C If the dam embankment used to impound fresh water is not
located on a watercourse, complete the following:

Is the dam located in a FEMA (Federal Emergency Management
Agency) designated floodway?
Yes
No

If the answer is yes, a Dam Permit may be required from the
Department’s Dam Safety Program and/or a restudy of the FEMA
Floodway may be required to assess the impacts of the dam on the
floodway. Coordination will also be required with the local
municipality to assure that they remain eligible for the National Flood
Insurance Program. Please submit information required in Section
6 to the Department’s Dam Safety Office for the determination of the
need for a permit or other approvals.
Worksheet for Permitting of
Marcellus Shale Pits and Dams

If this answer is no, continue with the following questions:

Is maximum depth greater than 15 feet?

Is maximum storage volume greater than 50 acre-feet? Yes No

If the answer to both of these questions is yes, a Dam Permit is
required from the Department’s Dam Safety Program. Please
submit form 3140-PM-WE0001, “Application for a Dam Permit”, and
information required on that form’s checklist to the Department’s
Dam Safety Office.
Yes
No
Worksheet for Permitting of
Marcellus Shale Pits and Dams

If the answer to either or both of the above questions is
no and the dam directly impacts a wetland, an
Environmental Assessment approval is required from the
Department’s Dam Safety Program. Please submit form
3140-PM-WE0002 Environmental Assessment
Information Sheet and information required on that
form’s checklist to the Department’s Dam Safety Office.
Utilize the Design, Construction and Maintenance
Standards for Pits and Dam Embankments Associated
with Impoundments for Oil and Gas Wells to develop
plans and specifications.

If the answer to either or both of the above questions is
no and the dam does not impact a wetland, no dam
permit is required.
Worksheet for Permitting of
Marcellus Shale Pits and Dams

4.
Centralized frac water storage (Fluids other than fresh water
(e.g. drilling or fracing fluids)):
4.A If a dam embankment will be constructed to create this
storage facility, proceed to Section 4.B.

If the storage facility is to be an excavated lined pit, the facility must
meet the requirements of PA Code Chapter 78.56 – 78.63 and the
Design, Construction and Maintenance Standards for Pits and Dam
Embankments Associated with Impoundments for Oil and Gas
Wells. Plans must include an acknowledgement that this pit will
meet the standards. Complete information requirements in Section
6 and Section 8 and submit to the appropriate Department Regional
Oil and Gas Program Office.
Worksheet for Permitting of
Marcellus Shale Pits and Dams

4.B A dam embankment will be constructed to impound frac water
and the following describes this impoundment:

Length

Width

Maximum potential depth of frac water

ft.
ft.
Storage Volume ____ ac.-ft.
ft.
Worksheet for Permitting of
Marcellus Shale Pits and Dams

4.C
This dam embankment to be constructed to impound frac water
is: (Please check appropriate box below)

a. Located on a watercourse.

b. Located off-stream, but impacts a wetland.

c. Located off-stream and in FEMA (Federal Emergency
Management Agency) Floodway.

d. Located off-stream, storage volume exceeds 50 acre feet
and depth of impoundment exceeds 15 feet as noted in 4.B
above.

e. Located off-stream, storage volume is less than 50 acre feet
or depth of impoundment is less than 15 feet as noted in 4.B
above.
Worksheet for Permitting of
Marcellus Shale Pits and Dams

If any of the boxes a through d are checked, a Dam Permit is
required from the Department’s Dam Safety Program. Please
submit Form 3140-PM-WE0001, “Application for a Dam Permit”, and
information required on that form’s checklist to the Department’s
Dam Safety Office. Also, submit information requirements in
Section 8. Utilize the Design, Construction and Maintenance
Standards for Pits and Dam Embankments Associated with
Impoundments for Oil and Gas Wells to develop plans and
specifications.

If box e, is checked, proceed to Section 5.
Worksheet for Permitting of
Marcellus Shale Pits and Dams

5.
Potential Impacts of Dam Failure
Failure of this frac water impoundment dam has the potential to:

Impact inhabited structures:

Cause significant property damage:

Flood roadways:
Yes
Yes
No
No
Yes
No
Worksheet for Permitting of
Marcellus Shale Pits and Dams

If yes to any of the dam failure impact questions, a Dam Permit is
required from the Department’s Dam Safety Program. Please
submit Form 3140-PM-WE0001, “Application for a Dam Permit”, and
information required on that form’s checklist to the Department’s
Dam Safety Office. Also, submit information requirements in
Section 8. Utilize the Design, Construction and Maintenance
Standards for Pits and Dam Embankments Associated with
Impoundments for Oil and Gas Wells to develop plans and
specifications.
Worksheet for Permitting of
Marcellus Shale Pits and Dams

If no to all of the questions above, a Dam Permit from the
Department’s Regional Bureau of Oil and Gas Management office is
required. Please submit form 5500-PM-OG0084, “Application For A
Dam Permit For A Centralized Impoundment Dam for Marcellus
Shale Gas Wells”, and information required on that form’s checklist
to the Department’s Regional Bureau of Oil and Gas Management
Office. Also, complete information requirements in Section 8.
Utilize the Design, Construction and Maintenance Standards for Pits
and Dam Embankments Associated with Impoundments for Oil and
Gas Wells to develop plans and specifications.
Worksheet for Permitting of
Marcellus Shale Pits and Dams

6.
Attach a copy of USGS 7½ minute quadrangle map
showing the location of the pit or dam and attach a site plan
and typical cross-sections of the pit or dam.
Worksheet for Permitting of
Marcellus Shale Pits and Dams
7. If a pit is proposed to store fresh water, no Dam Permit is required.
However, if the pit is located on a watercourse, in the floodway of a
watercourse, or in a wetland, a Water Obstruction and Encroachments
Permit is required.
Please submit Form 3930-PM-WE0036 Joint Permit Application and
information on that form’s checklist to the Department’s appropriate
Regional Office, Permitting and Technical Services Section.
8. Attach site restoration plan for all frac water impoundment pits and
dams. Frac water impoundments pits or dam sites must be restored
within nine months after completion of the last well that was serviced
by the impoundment.
Centralized Impoundments
Well Site Pits and Impoundments

Pits and impoundments located on the drilling
site will be authorized by the Oil and Gas Well
Permit. These impoundments must follow the
Construction Standards.
Construction Standards for
Dams and Embankments
Associated with Pits and
Impoundments for Oil and
Gas Wells
Construction Standards
The operator may use alternate construction standards
if they meet or exceed the Department’s Construction
Standards, if they are developed, sealed and certified
by a professional engineer registered in Pennsylvania;
and if they are approved through a Dam P Application
process through the Department’s Division of Dam
Safety prior to commencement of construction.
Construction Standards

Soils to be used for dam embankment
construction must be classified in accordance
with ASTMD-2487 (Unified Soils Classification).
A minimum of three samples must be classified.

Soils acceptable for dam embankment
construction are limited to GC, GM, SC, SM, CL
or ML. Soils must contain a minimum of 20% of
Plus No. 200 sieve materials.
Gradation
Sheet
GC- Clayey gravels
GM- Silty gravels
SC- Clayey sands
SM- Silty sands
CL- Inorganic clays low to
medium plasticity
ML- Inorganic silts and fine
sand, slight plasticity
Site Preparation

Foundation of dam embankment must be stripped and
grubbed to a depth of two feet prior to any placement &
compaction of earthfill.

Any springs encountered in the foundation area should
be drained to the outside/downstream toe of the
embankment with a drain section two foot by two foot in
dimension consisting of PennDOT Type A sand,
compacted by hand tamper. No geotextiles to be used
around sand. The last three feet of this drain at the
outside/downstream slope should be AASHTO #8
material.
Compaction

All compaction for embankments must be done with a
sheepsfoot or pad roller.

Loose lift thickness must be 9” or less.

Maximum particle size is 6”.

A minimum of 5 passes of the compaction equipment
over the entire surface of each lift is required.

Compaction to visible non-movement of the
embankment material is required.
Soil Placement and Compaction
Pad Rollers
Design Criteria

Minimum embankment top width of 12’ is required.

Minimum inside & outside sideslopes of 3H:1V are
required.

All exposed embankment slopes must be limed,
fertilized, seeded and mulched. Permanent vegetative
ground covering compliance with PA Code Chapter
102.22 must be established upon completion of dam
construction.

2’ of lined freeboard must be maintained at all times.
Embankment Top Width
Minimum 12’
Take a closer look…..
Failure to properly compact
movement of the embankment material
Failure to maintain 2 feet of lined
freeboard
Selecting the Correct Liner
The Geosynthetic Institute- GM13
A standard specification
for High Density
Polyethylene
Geomembranes
Addresses the amount
of recycled or re-worked
material allowed in the
formulation of the liner
(No more than 10%)
No Post consumer
resins of any type can
be added
CH 78 addresses the
EPA Method 9090, The
Compatibility of Wastes
and Liners
CH 78 addresses the minimum
thickness of liners used for the
disposal of residual wastes.
How thick must a liner be for these
centralized impoundments?
The large volumes of stored liquid
and hydrostatic pressures creates
an increased potential for possible
failure.
Only 30 mil liners are allowed.
Only a synthetic liner can be used.
Compacted clays or earthen
materials are not allowed
Failed 20 mil liners
(two separate locations)
Failed 20 mil liner
Groundwater Monitoring
Groundwater Monitoring
An operator shall collect background data prior to
the construction of the impoundment. This
attempt is to establish baseline background data
for the groundwater where the impoundment is to
be constructed. In the event that the
impoundment was already constructed, safe
drinking water levels apply.
Groundwater Monitoring




A groundwater monitoring/protection plan is required for all
impoundments that will remain longer than 9 months.
Applying the Residual Waste Regulations... CH 289 and 299
address the number and placement of monitoring wells for
these types of impoundments.
The well casing standards are also addressed in these chapters.
The operator will monitor the groundwater (at a minimum) on a
monthly basis. The operator will also maintain this data. The
gathered information must be made available upon DEP
request.
Groundwater Monitoring
The following parameters (at a minimum) must be
monitored and tested for:
pH
Specific Conductance
TDS
Chloride
Sulfates
Groundwater Monitoring
In the event of groundwater contamination,
the operator must notify the appropriate
regional DEP office within 24 hours of the
incident.
Groundwater Monitoring
Prior to restoration, the operator must
affirm and attest that no contamination
occurred.
If contamination occurred, the operator
must first affirm that the contamination
was mitigated and corrected.
Immediately following the restoration of
the impoundment, the monitoring wells
then shall be plugged.
Leak Detection
Typically is comparable to a
French drain system that is
installed between the upper
impoundment liner and a
lower second containment
liner. A riser pipe is
connected to the drain
system allowing an operator
to monitor for the presence
of water in this zone.
Typical Problems with this
system are ground water
intrusion and liner failures
or punctures.
Use of a subbase
As previously
mentioned, the
subgrade should be
well compacted and
present a surface
free of rocks,
stones or anything
that might puncture
the liner.
There should be no
abrupt grade
changes, voids or
surface
discontinuities.
Use of a subbase



In the event that it is
impractical to remove all of the
rocks from the subgrade, at
least six inches of screened soil
or other acceptable material
must be used to provide a
protective cushion
A cushioning geotextile is also
acceptable and recommended.
In the event that protrusions
can not be removed or
protected against, the
impoundment is likely to
FAIL.
Impoundment
(under construction)
3 to 1 inside and outside slopes
min 12’ embankment top width
proper compaction
maximum particle size is less
than 6”
screened soil as a subbase
Do not utilize organic matter as a
subbase
The Decomposition of organic matter
produces gas and results in the potential for
the liner to burst or rupture!
Vegetation
Dam embankments must be maintained with a
grassy vegetative cover, free of brush and trees.
Reasonable
protection from
unauthorized acts of
third parties
Ch 78.56 (a) (3).
Restoration
Prior to the site restoration, all of the liquid fraction of waste must be disposed
of at an approved treatment facility or reused at another well site.
If the remaining residual waste meets CH 78 regulations relating to:
the Characteristics of toxicity, the contaminants in the leachate from the waste
does not exceed 50 times the safe drinking water level and the concentration of
contaminants in the leachate from the waste does not exceed 50 times the primary
maximum contaminant level…
then the waste can be disposed of in accordance with CH 78 on-site.
Restoration
If the remaining solid waste fraction was generated from only one well
site, then the residual solid waste and liner can be disposed of in accordance
with CH 78.
If the residual waste does not meet CH 78 requirements, then the
residual waste must be hauled off-site and then disposed of at an approved
disposal facility.
If the residual solid waste was generated from MULTIPLE well sites,
then this waste and liner must be removed and hauled to an approved landfill.
This portion of waste can not be land applied or encapsulated on site.
Jim Kline
Mineral Resources Program Specialist
Division of Resource Management &
Well Development
DEP - Bureau of Oil & Gas
Management
814-472-1903
jamekline@state.pa.us
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