REV05698

• Permit No: M1985029
• IBM Index Class Name: Revision
• Doc Name: FAX COVER
• From: DOW
• To: LARRY OEHLER
• Type & Sequence: AM3
• Media Type: D
• Archive: No

DOW COLD SPRINGS TEL [phone] May 23.90 11:47 No.006 P.02
• •
recirculation ponds and plans for upgradi g existing
impoundments, 3) intended use of the 5 dams shown in Plate 4,
~ ,. and a) add a surface water diversion for the nort west corner
of the permit area.
~:

Please see the discussion provided in Exhibit D, under the new
heading entitled "Sediment and Drainage Controls".
prevention of Discharge/Flood Protection
12.
The application has pzoposed a minimum setback di tance of 50
feet from the South Platte River. The Division as several
concerns regarding demonstration of compliance wit applicable
State and Federal Regulations, particularly the lean Water
ACt.
The Clean Water Act requires that berms, pond wal s, ditches,
low dams and similar water retention structures be onstructed
in a manner such that they are reasonably expect to reject
the passage of water.
In order to demonstrate compliance with the Clea Water Act,
we suggest that Reclamation Resources Choose ne of the
following options:
Option 1
X
Define the 25-year floodplain for the Middle Fork ~
Platte River. Commit to restricting all mining
outside of the 25-year floodplain. Since the
life-of-mine for the Alma Placer is ten years, t
has deemed the 25 year-24 hour storm as an approps
criteria. _~ ~f~~_
option 2 w'~ ~~ '"'~~~ ~"T"^
~~~~ - ~A~~~ ~ D/A.~rlart Gt4~
Commit to construction of a berm along the west
operation which will be of adequate size to reje
of a 25 year-24 hour storm for the Middle Fark o
Platte River. Provide a berm design which include
freeboard of 1 foot above the water surface eleva
25 year-24 hour storm.
if Option 2 is chosen, the following
submitted:
a. An estimate of the 25-year peak flow discha
b. The elevation of the river water surface at
flow condition in relation to the berm.
c. A description of berm re-enforcement measure
riprap and riprap size to insure channel stabs
year flow conditions;
f the South
operations
anticipated
ie Division
Late design ~/"-~~~
side of the
:t the flow
the South
s a minimum
:ion of the
should be
e;
he 25-year
s, such as
sty at 25-