Module 13: Impoundments

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Module 13: Impoundments


Provide the following information for each impoundment that will be used in operations under this permit. Organize
the information by site and facility.

13.1

General

a.

Identify the impoundment so that it can be keyed to Exhibit
9.1.

b.

Describe the function of the impoundment.

c.

Attach site
-
specific cross sections of the impoundment showing: the principal spillway, dewatering pipe,
depth of water, crest of emergency spillway, maximum height of embankment, and existing ground.
Label t
he cross
-
section Exhibit 13.1


Impoundment Cross
-
Section.

d.

Describe the potential effect of mine subsidence on the impoundment structure.

e.

Provide plans and describe procedures to compute accurate discharge flow rates from sediment and
treatment pond princi
pal spillways and dewatering pipes. The field system as well as the calculation
method must be usable by monitoring personnel and PADEP mine inspectors.

13.2

Detailed Design Plan

Include a design report, capacity calculations, construction plans, construc
tion specifications, and
Form

13.2A. If the embankment is more than 20 feet in height as measured from the upstream toe of the
embankment to the crest of the emergency spillway, or has a storage volume of 20 acre feet or more provide
a stability analysis.

All plans must be certified by a licensed professional engineer. Impoundments must be
certified by a licensed professional engineer and approved by the Department before being put into service.

13.3

Compliance with 25 Pa Code Chapter 105

Indicate whethe
r or not the impoundment meets the criteria for coverage under Chapter

105
-

contributory
drainage area exceeding 100 acres, water depth exceeding 15 feet (measured by the upstream toe of the
dam at maximum storage elevation), or impounding capacity exceed
ing 50

acre
-
feet at maximum storage
elevation. Applications for Chapter 105 dams are subject to additional application fees (see Module 1:
Section E, Application Fee).

13.4

Groundwater Protection

a.

Describe the quality of water that will be contained in the

impoundment.

b.

Where impounded water has the potential to cause groundwater contamination or to aggravate an
existing groundwater problem:

i.

Show the liner on the cross section drawings in Module 13.1; and

ii.

Complete Module 14.

13.5

Operation and Maintenance
Requirements

Describe the operation and maintenance requirements for the structure, including:

a.

Scope and frequency of inspections;

b.

Dewatering of runoff collection ponds following storm events;

c.

Sludge removal operations;

d.

Maintenance of embankments and liner
s; and

e.

Monitoring.

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FORM 13.2A:
IMPOUNDMENT DESIGN AND CERTIFICATION


Commonwealth of Pennsylvania

Department of Environmental Protection

Bureau of Mining and Reclamation

Permittee








Permit No.








Pond








Township








County








Engineer/Land Surveyor








Date








INSTRUCTIONS

Complete first page and submit with permit
application. Use both pages to certify completed impoundment.

Sedimentation ponds and other impoundments must be constructed in accordance with the approved permit before any disturbance
of the area to be
drained into the pond. Impoundment must be inspect
ed during construction under the supervision of, and certified to the Department upon completion of
construction by a licensed professional engineer or licensed professional land surveyor.

Any enlargement, reduction in size, reconstruction, or other modifi
cation, that may affect the stability or operation must be approved by the Department.
Pond must be certified and approved prior to the start of any other mining activities (see reference sheet


page 13
-

4 of this module).

Unless otherwise specified in
your permit, use this form for the sedimentation pond and other impoundment certification. Submit 1 original and 2 copies to

the appropriate District Mining Office. All information must be provided, otherwise it will be returned for completion.


U.S.G.S.

Quadrangle:







Location (point of discharge):

Latitude






;

Longitude







or

Location from
Bottom Right

corner of U.S.G.S.

Quadrangle:







inches

North






inches


West







HYDROLOGY: Drainage Area







acres

Design Storm







Average Watershed Slope







Land Use







Soil Type







Curve Number







Peak Discharge










Permit Application

As Constructed

Embankment

Top Width (Minimum)














Outside Slope (Maximum) (_H: _ V)














Inside Slope (Maximum)














Top Elevation














Bottom Elevation














Upstream Toe Elevation














Downstream Toe Elevation














Amount Allowed for Settlement














Type of Cover














Incised Slope (if any)














Inside Slope (Maximum) (_H: _V)














Top Elevation














Bottom Elevation













Dewatering

Type/Size













Device

Inlet Elevation














Discharge Regulation (i.e., self draining or valve)














Discharge Capacity (cubic feet/second)














Time to Dewater Full Pond














Type













Principal

Conduit Diameter (if barrel/riser give both)













Spillway

Inlet Elevation














Outlet Protection














Spillway Capacity













Emergency

Type













Spillway

Width














Depth (with 2 feet of freeboard)














Length














Side slopes














Crest Elevation














Slope














Type of Lining/Protection














Spillway Capacity (provide design calculations)













Storage

Length @ Bottom













Capacity

Width @ Bottom














Length @ Dewatering Device














Width @ Dewatering Device














Volume @ Dewatering Device














Length @ Crest of Principal Spillway














Width @ Crest of Principal Spillway














Volume @ Crest of Principal Spil
lway














Length @ Crest of Emergency Spillway














Width @ Crest of Emergency
Spillway














Volume @ Crest of Emergency Spillway













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Permit No.








Pond








Twp./County








Engineer








Date








TO BE COMPLETED AFTER CONSTRUCTION

1.

Has the facility been constructed at the location shown in the approved permit?

Yes

No


2.

Is emergency spillway constructed in original ground?

Yes

No


And is the type of construction adequate for the required duration and

discharge of the design storm? If “no”
checked, explain.

Yes

No


3.

Are the collection channels inlets constructed at the proper
locations

and located to prevent short
-
circuiting?

Yes

No


4.

Has the pond liner been
constructed as outlined in Module 14? (Provide liner

testing documentation)

Yes

No

N/A


If not constructed as approved, answer the following questions:


5.

Is the “as constructed” design capable of meeting the performance standards?

Yes

No

If “no” checked, explain.








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Construction Inspection

Date of Inspection


Inspected By


Stage of Construction
































































Supervising Professional Engineer







Address







Telephone Number







I certify that the above
-
mentioned structure
is complete and has been constructed as indicated.





Signature of Professional Engineer/Surveyor

Date




SEAL



Registration Number and Expiration

Date












Signature of Permittee or Responsible Official

Date


Title

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Embankment


































Principal Spillway Principal Spillway

(Barrel/Riser) (Barrel Only)




























Emergency Spillway

(To be Constructed in Original Ground)

























Top Width

Top Elev.

H

V

H

V

Outside
Slope

Inside
Slope

Original Ground

H

V

Incised Slope
Inside Slope

Incised Slope
Bottom Elev.
Slope

Incised Slope
Top Elev. &
Upstream Toe
Elev.

Downstream Toe Elev.

Bo
ttom Elev.

Principal Spillway
Inlet Elev.

Dewatering
Device Inlet
Elev.

Principal Spillway
Riser Diameter

Principal Spillway
Barrel Diameter

Principal Spillway
Conduit Diameter

Principal Spillway
Inlet Elev.

Dewatering
Device Inlet
Elev.

Length

Cr
est Elev.

Slope

Depth + 2’
of Freeboard

V

H

H

V

Width

Sideslopes

Sideslopes

Depth + 2’ of
Freeboard

Crest Elev.

Cut
-
off
Trench

Reference Sheet for Form 13.2A