appendix c agency correspondencelookoutmountainwaterdistrict.org/wp-content/...bottom of chimney...
TRANSCRIPT
APPENDIX C
AGENCY CORRESPONDENCE
September 8, 2017
Mr. Steve Turner, State Historic Preservation Officer
History Colorado
1200 Broadway
Denver, Colorado 80203
RE: FEMA 97.047 CFDA Title Pre-Disaster Mitigation - Project: Risk Reduction Spillway and Dam
Safety Modifications at Lower Beaver Brook
Dear Mr. Turner:
This letter is to inform your agency of the proposed Risk Reduction Spillway and Dam Safety Modifications at Lower Beaver Brook Dam Project (Project) and to request feedback from your agency regarding the
project’s proposed scope of work that may have the potential to impact historical areas, properties, or
artifacts. The Colorado Division of Homeland Security and Emergency Management has requested we
contact the State Historic Preservation Office (SHPO) to solicit informal comments on this project so the
Lookout Mountain Water District can better evaluate the potential impacts to the project implementation,
cost estimate, and timeline. We understand that that any formal review and coordination will be directly
with FEMA. W. W. Wheeler and Associates, Inc. (Wheeler) is submitting this information on behalf of the
Lookout Mountain Water District (District), the owner of Lower Beaver Brook Dam.
Lower Beaver Brook Dam is a small, high-hazard potential, concrete-face rockfill dam located in Clear
Creek County, Colorado. The dam was originally constructed in 1903 and has several dam safety
deficiencies. The proposed project involves constructing a new concrete gravity dam immediately
downstream of the existing dam to address the identified dam safety deficiencies. Additional information
on the Project is provided in the following attachments:
1. A project location map;
2. A description of the background, description of the proposed conceptual design, and preliminary
conceptual drawings;
3. Aerial image and photographs of the existing Lower Beaver Brook Dam site;
4. 1936 Engineering Drawings of the existing Lower Beaver Brook Dam
We are requesting that your agency provide a written response within 30 days with information concerning
your area of expertise with the project to allow the District to complete the environmental scoping. We
request that you please send a response in regard to this Project even if no potential impacts are identified
and no further consideration is needed with your agency. Please call or e-mail if we can provide you with
additional information to assist in the review. We appreciate your time and look forward to your response.
Sincerely,
Danielle Hannes, P.E.
W. W. Wheeler and Associates, Inc. r:\1800\1867\1867.01_lowerbbdam\documents\fema_coordination\170905_shpo_letter.docx
Attachment 1
Project Site Location Map
!!
!
!
!
! ! ! ! ! ! ! ! ! ! ! ! !
!!
!
!!!!!!!!!!!!
!
!
! !
!!
!!!
!!!
! ! ! ! ! !
!
!!
!!!
!!!
!!
!!
! !
!!
!
!! !
!!!
! ! ! ! ! ! ! ! ! ! ! !
!!
!
!!!!!!!!!!!!
! !
!
!
! ! ! ! !
!!
!
!!
!
!!!!!!!!!
!!
!!
!!
! ! !
!!
!!
!!
!!
!
! ! ! ! ! ! ! ! ! ! !
!!
!!
!!
!
!!!!!!!!!!!!
!!!!!!!!
!!
!!
!!
!
! ! ! ! ! ! !!
!!
!!
!!
!
!!!!!!
!
!
!!
!
!
! ! ! ! ! !
!!
!
!
!!! !
!
!!
!
!
!!
!
!
!
! !
!!
!
!!
!
! !
!
!
!!
!
!!
!
!!
!!!
!!
!
!!
!
!!
!
!!
!
! ! ! ! ! !
!!!!!!!!!!!!
!!
!!
!!
! ! ! ! ! !! ! ! ! !
!!
!!
!!
!
!!!!!!
!
!!
! ! !
!!!
!
!!
! ! !!!!
!!!
!!!!!!!
!!
!
!!
!
! ! ! ! ! !
!!
!!
!
!!
!!
!!!!!!
!
!!
!
!
!
!!!
!
! !
! ! !
!!
!!
!!
!
!!!!!
!!
!!
!!
! ! ! ! !
!!
!!
!!
!
!
!
!!
!
!!
!
!!
!
!
! ! ! ! ! ! ! !
!!!!!!!!!
!!
!
!!
!
!
!
!
!
!
!
!!!
!!
!!
!!
! ! !
!
! !
!
!
!
!
!!
!!!
!!!
!!
!
! !!!
!!
! !!
!
! !
! !!
!
!!
!!!!!!!!!
!!!
!!
!!
! !! ! ! ! ! !
!!
! ! ! ! !!!
!!
!!!!!!!!!
!
!
!!
!
!
!
!!!!
!!
!!
!
! ! ! ! ! !
!!!
! !
!
!!
!
!!!
!!
!!!!!!!
!!
!
! ! ! ! ! ! ! ! ! !
!!
!!
!!
!!
!!!!!!!!!
!!
!
!!!
!!
!!
!!!!!!!!
!!
!
! ! ! ! ! ! ! ! ! !!
!!
!!
!!
!
!!!!
! ! !
! ! !
!!
!!
!!!!!!!!!!!
!
!!
!
!!
! ! ! ! ! !
!!
!
!!
!!
!!
!!
!!!!!!!!!!!!!!!!!!!
!!
!
! ! !! ! !
! ! ! ! ! !
!!
! ! ! !
!!
!
!!
!
! !
!!
!
!!!
!
!!
! ! !
!!!
!!
!
!
!
!
!!
!
!!
!
!!
!
!!!
!!
!!
!!
! !
!
!!!
!
! !! !
!
!
!
!
!
!!
!
!
!!
! ! !
!
!!
!!!
!! !
!
!!
!!
!
!!!
!!
!
!!!!!!
!!
!!
!!!!!
!
!!
! ! !!
!!
!!
!!
!!
!!
!
!!
!
!!!
!!
!!
!!
!!!
!!
!!
!
!
!
!
!!!
!
! ! ! ! ! !
!
!!
! ! !
!! !
!!
!
!
!!
!!!
!
!!
!!
!
!!
!
!
!!
!
!!
!!
!
!
!
!
!
!
!
!
!
!
!
!
!!
!
!
!
!
!!
!
!!
!
!!
!!!!
!!
!!
!
!!
!
!
!
!
!!
! ! ! ! ! ! !
! ! ! !!!!
!
!
!!
!
!
!!
!!!
!!
!!!
!!
!!
!!
!!
! !
!!!!!!!!!!!!!!!
!!
!
! ! !
!!
!
! ! ! ! ! ! ! ! ! !!!
!!
!
!!!!!!!!!!!!
!
!!
!!
!
! ! ! ! ! ! ! ! !! ! !
!!
!!
!!
! ! ! ! ! !
!!
!!
!!
!!
!!!!!!!!!!
!!
!
!
!!
!!
!
!
! !
!
!
!
!!
!!!!!
! !
!
!
!! ! !
!!!!!!!!
!
!!!
!!
!
!
!
!
!
!!
! ! ! ! ! ! ! ! ! ! ! !
!!
!!
!!
!!
!
!!
!
! ! ! ! ! ! ! ! !
!!
!!
!!
!!
!
!!!!!!!!!!!!!!!!!!!!!
!!
!
!
!!
!! !
!
!
!
!!
!
!!
!
!!
!!
!!
!!!!!!!!!!!
!!
!!
! ! !
!!
!!
!!
!!
!
! ! ! ! ! !
!!
!!
!
!
!!
!!
!!
!!!!!!
!!
!
!!
!!
!!
! ! ! ! ! ! ! ! !
!!
!
!
!
!
!!!
!!
!
!!
!
!
!!
!!
!
!!
!
!!!!!!!!!
!!
!!
!!
!!
!
! ! ! ! ! ! ! ! ! ! ! ! ! ! !
!!
!!
!!
!!!!!
!!
!!
!!
!
!
! !
! ! !
!!
!!
!!
!
!!!
!!
!!!!!!!!!!!!!!!
!!
!!
!!
!!
!!
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
!
!!
!!
!
!!
!
!!
!
!!!!!!!!
!!
!!
!!
!
! ! ! ! ! ! ! ! !
!!
!!
!!
!
!!!!!
!!
!
!!!!!!!!!!!!
!!
!!
!
! ! ! ! ! ! !
!!
! ! ! ! ! ! ! !
!!
!!
!!
!!!!!!
!!
!!
!!
!!
! ! ! ! ! ! !
!!!!!!!!
!!
!!
!!
!! !
!
!!
!
! ! !
!!
!!
!!
!
!!
!
!!
!!!
!
!!
!
!!
!!
!
!!
! ! ! !
!
!!
!!
!!
!!!
!!
!
!!!!!!
!!
!
!
!!
!!
!
!!
!
!!
!
!!!
!
!!
! ! !
!!!!!!!!
!!!
! ! ! ! ! !!!
!!
! ! ! ! ! ! ! !!
!
!!
!!
!
!!
!
!!!
!!!
!!
!
!!!
! ! !
!!!!!!!!!
!!
!!
!!
! ! ! ! ! ! ! !
!!
!!
!!
!
!!
!!
!!
!!
!
!!
!
!!!
!
!!!
!!
!
!!
!
! ! ! ! ! ! ! ! !!!
!!
!
! ! ! ! !
!
!!!
!!
!
!!
!!!!
!!
!
!!!!!!
!!!!!!
!!
!!
!!
! ! ! ! ! ! ! ! ! ! ! ! ! ! !
! ! !!
!!
!!!!!!!!
!!!
!
! !!
! ! ! ! !
!!
!
!
!!
!
!!
!!
!!
!
!
!
!!
!
!!!!!
!!
!
!!!!!!
!!
!
!
!!
!!
!
! ! ! ! !
!!!!!!
!!
!
!!!
!!
!!
!!
! ! ! ! ! ! ! ! !
!!!
!
! !
! !!
!
!
!
!!!
!!!!!!
!
!
!
!
!
!
!!!!!!
!
!
!
!!!
! !
!!
!
!! !
!
!
!
!!!
!!!
!!!!!!!!!
!!
!
! ! ! ! ! ! ! ! ! ! !
!!!!!!!!
!
! ! ! ! ! !
!!
!
!
!
!
!
!
!
!
!
!
!!!
!
!
!
!
!
!
!
!
!
!!!
!
! !
!
!!
!!
!!
!
!
!!
!
!!!
!!!
!!
!
! ! !
!!!!!!!!!!!
!!
!!
! ! !
!!
!!
!!
! ! ! ! ! !
!!
!!
!!
!!
!!
!!
!!
!!
!
!
!!
!!
!!
!!
!
! ! ! ! ! ! ! ! ! ! ! !
!!
!!
!!
!!!!!!
!!
!!
!!
!!!!!!!!!!!
!
!!!!!!!!!
!!
!!
!!
!!
!!
! ! ! ! ! ! ! !
!!
!!
!!
!!
!!!
Walsenburg
Trinidad
BrightonBrighton
Castle RockCastle Rock
Canon CityCanon City
AvonAvon
MontroseMontrose
DurangoDurango
EvergreenEvergreenSilverthorneSilverthorne
SterlingSterling
Fort MorganFort Morgan
Woodland ParkWoodland Park
Denver Metro Area
Colorado SpringsColorado Springs
§̈¦70
§̈¦25
§̈¦470
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!
!
!!
!
!
!!
!
!
!
!!
!!
!!
!
!!
!!
!
! ! !
!!
!
!! !
!!
!
!!
!
!!
!
!!
!!
!!
!!
!
!!
!
!!!
!!!!!!
!!!
!!
!
!!
!!!!
!!
!
!!
!!!!
!!
!
!!
!
!!
!
!!!!!!
!!
!
!!
!
!!!
!!
!
!!!
!!
!
!!
!
!!
!
!
!
!
!!
!
!!
!
!!
!!
!!
!!
!!
!!
!!
!
!
!!
!!
!
!
!!
!!! ! !
!
!!
!
!!
!
!!
!!
!!
!!
!
!!
!
!!
!
!!
!
!!
!!
!!
!!
!
!!
!!
!!
! ! !
! !
!
! ! ! ! !!
!!
!
!!
! ! ! !
! ! ! ! !!
!
!!
! ! !
!!
!
!
!!
!!
!
! !!
! !!
!!
!
!!
!
!! !
!
!!
!!
!
! !
!
! ! !
!!
!
!!
!
!!
!
!!
!
!!
!
!!
!
!!
! !! ! !
!!
!!
!
!!
!
!
!!
! !!
!
!! !
! !
!!
!! ! !
!
!
!! !
!
!!
!
!!!
!!
!
!
!
!
!!
!
! !!
! ! !
!!
!
!!
!
! ! ! ! ! !
!
!
!
!!
!
!
!!
!!
!
!
!
!
! ! !
!!
!
!
!!
!!
!
!!
!
!!!
!!
!
!!
!
!! !
!!
!
!!
!
! ! !
! ! ! ! !!
!
!!
!!
!
! ! ! ! ! !
!
!
!! ! !
! ! !
!!
!
!! !
! !!
! !! !
!!
!!
!
!!
!
! ! !
!!
!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!
!!
!!
!
!!!
!!
!!
!!
!!!
!!!!!
!
!!!
!!!!
!
!!
!!
!!!
!!!
!
!!
!
!!
!!
!
!!!
!!
!
!!!
!
!!
!!!
!!
!
!!!
!!
!
!!!
!!
!
!!
!
!!!
!!
!
!!!
!!
!
!!
!
! ! !
!!
!
!!!!!
!
!
!
!
!!!
!
!!
!!!
!
!!
!!!
!!
!
!!
!
!
!!
!!!
!!!
!!!
!!!
!!!
!!
!
!!!
!
!
!
!!
!
!!
!!
!!
!!!
!!
!
!!
!
!!
!
!
!!
!
!!
!!
!
!!
!
!
!!
!
!!
!!
!
!!
!
!! ! ! ! ! ! ! !
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
!!
!
!! !
!
! !
!!
!! ! !
!!
!
!
!
!
! ! !
!!
!
!!
!!
!!
!!
!!
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
!!!
!!!
!!!
!!
!!
!!
!!
!
! ! !
! ! !
! ! ! ! ! !
!
!!
!
!!
!!
!!
!
!!!!!!!
!!
!!
!!
! ! ! ! ! ! ! ! ! ! ! ! ! ! !!!
!
!!
!
!!
!
!!
!
! !!
! ! !
! ! ! ! ! !
!!
!
! ! ! !
!!
!!
!
!
!! ! ! !!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!
!!!!
!
!
!!
!!
!!
! ! ! ! !!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!!
!!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!
!!
!!!
!
! ! ! ! !
!!
!
!!!!!!
!
!
!
!!
!
!!
!
! !!
! ! !
!!
!
!!
!
!
! ! !!!
!!!
!
!!
!
! !
!!!!
!!
!!!
!!
!!!!!!!
!!
!
! !
!
! ! ! ! ! !
!!
!
! !! ! !
!
!! !
!!!
!!!
!!
!
!
!!!!!!!!!!!!!!
! ! ! ! ! ! ! ! ! ! ! ! ! ! !
!!
!
! ! !
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!
! !!
!!!
!!
!
!!!
!!
!
!!
!
!!
!
!!
!
!!
!
!
!!
!!
!!
!!
!!!
!!
!
!!
!!
!!
!!
!
!!
!
!!!
!!!
!
!!
!
!!
!
!!
!!
!
!!
!
!
!!
!!
!
!
!!
!!
!!
!
!
!!
!!
!!
!!!
!
!!
!!
!
!
!!
!!
!
!!!!
!
!
!
!!
!!
!
!!
!
!!
!
!
!!
!
!
!
!!
!
!
!!
! !
!
!!
!
!!
!!
!!
!!
!!
!!
!!
!
!!
!
!!!
!
!
!
!!
!
!
!
!
!
!!
!!
!
!!
!
!
!
!
!
!!
!!!
!!!
!!
!
!
!!
!!
!
!
!!
!!
!
!!
!
!
!!
!
!
!
!!
!
!!
!
!!!
!!
!
!
!!
!!
!
!!
!
!!!
!!!
!
!!
!!
!
!!
!!
!!
!
!!
!!
!
!
!!
!!
!
!
!!
!!
!
!!!
!!
!
!!
!
!!
!!
!!
!
!!
!!
!
!!
!
!!!
!!
!
!
!!!
!!
!!
!
!!
!!
!!
!!!
!!
!!
!!
!!
!
!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
!!
!
!!
!
!!
! !!
!!
!!
! !!
!!!
!!!
!!
!
!
! !
Lower Beaver Brook Dam
Upper Beaver Brook Dam
Jefferson CountyClear Creek County
Clear Creek
q
q 0 1 2
Miles
COLORADO
0 60 120
Miles
R:\
18
00
\18
67
\18
67
.01
_L
ow
erB
BD
am
\GIS
\MX
D\L
oca
tio
n_
Ma
p.m
xd
Job. #: 1867.01 FIGURE 1
Lower Beaver Brook DamAlternative Analysis Report
Location Map
JU
LY
201
7
Attachment 2
Project Information
Background, Description, and Conceptual Drawings
Risk Reduction Spillway and Dam Safety Modifications at Lower Beaver Brook Project
BACKGROUND & CONCEPTUAL DESIGN DESCRIPTION
General Project Background
Lower Beaver Brook Dam is a small, high-hazard, concrete-face rockfill dam located in Clear
Creek County, Colorado. The dam was originally constructed in 1903 and is owned by the
Lookout Mountain Water District (District). Several dam safety deficiencies have been identified
at Lower Beaver Brook Dam during the Colorado Division of Water Resources (DWR) Dam Safety
Engineer inspections including a significantly undersized spillway for passing the required inflow
design flood; uncontrolled embankment and/or foundation seepage; concerns associated with the
stability of the dam embankment; and concerns associated with the age of the outlet works
components. Six alternatives were evaluated to mitigate the dam safety issues which are
documented in the Lower Beaver Brook Dam, Alternatives Analysis Report for Dam Safety Mitigation by W. W. Wheeler and Associates, Inc. (Wheeler) dated July 2017. After considering
each alternative’s ability to adequately address the dam safety issues; their construction and long-
term stability; their ability to maintain the existing normal pool for operations and long-term
environmental impacts to habitat and wetlands; and their expected future maintenance work; the
new concrete dam alternative was considered to be the preferred alternative by the District.
Project Conceptual Design Description – New Concrete Dam
The proposed project includes removing the existing embankment dam and constructing a new
concrete gravity dam immediately downstream of the existing dam. The conceptual design of the
new concrete gravity dam is based on Wheeler’s experience with dam construction and judgment.
Some modifications are expected to be made during final design.
The new concrete dam was assumed to be constructed of Roller Compacted Concrete (RCC) in
the conceptual design, with a non-overflow dam crest at elevation 7845 at each end, with a central
emergency spillway in the middle. The emergency spillway is planned to be approximately 125
feet wide with a crest elevation of 7840. The existing service spillway on the right abutment will
be rehabilitated to maintain the same reservoir normal pool elevation of 7837.7. The rehabilitated
existing spillway and new emergency spillway are adequately sized to pass the required inflow
design flood without overtopping the dam crest.
The RCC section has a vertical upstream face, a 20-foot-wide crest, and vertical chimney section
from the crest to elevation 7815, and a 0.8H:1V (horizontal: vertical) downstream face from
elevation 7815 to the toe of the dam. The upstream face, dam crest, and the downstream face
are protected from freeze-thaw damages with a grout-enriched RCC. A 20-foot-wide RCC stilling
basin is provided at the downstream toe to dissipate energy from the emergency spillway flow. It
is anticipated that the existing rockfill embankment will supply adequate materials for the new
RCC dam.
The outlet works of the new dam consists of two slide gates mounted on the upstream face of the
dam, with an 18-inch-diameter steel outlet pipe in the dam. The two slide gates will provide a
multi-level withdrawal from the reservoir. The release from the outlet pipe is bifurcated at the
downstream toe: one pipe providing water supply to the treatment facility, and one pipe for
reservoir drawdown. The reservoir drawdown pipe enters into the same RCC stilling basin that
is used for the spillway.
0+
00
1+
00
2
+
0
0
2+
77
7800
7
8
0
0
7805
7
8
0
5
7810
7
8
1
0
7
8
1
5
7
8
1
5
7820
7
8
2
0
7
8
2
5
7
8
2
5
7
8
3
0
7
8
3
0
7
8
3
5
7
8
3
5
7
8
4
0
7840
7
8
4
5
7
8
4
5
7850
7
8
5
0
7855
7855
7860
7860
7
8
6
5
7
8
6
5
7
8
7
0
7870
7
8
7
5
7
8
8
0
7
8
0
5
7
8
1
0
7
8
1
5
7
8
2
0
7825
7830
7
8
3
5
7840
7
8
0
5
7
8
1
0
7815
7820
7825
7
8
3
0
7835
ELE
VA
TIO
N (F
EE
T)
ELE
VA
TIO
N (F
EE
T)
7780
7785
7790
7795
7800
7805
7810
7815
7820
7825
7830
7835
7840
7845
7850
7855
7860
7780
7785
7790
7795
7800
7805
7810
7815
7820
7825
7830
7835
7840
7845
7850
7855
7860
0+00 1+00 2+00 2+77
PRELIMINARY ONLY
NOT FOR
CONSTRUCTION
THIS DRAWING TOGETHER WITH ITS PARENT ELECTRONIC MEDIAFILE IS THE PROPERTY OF W. W. WHEELER & ASSOCIATES, UNLESSOTHERWISE EXCEPTED, OR SUPERSEDED BY WRITTEN AGREEMENTWITH THE CLIENT LISTED IN THE TITLE BLOCK. IT IS FURNISHEDON THE EXPRESS CONDITION THAT IT SHALL NOT BE REPRODUCED,COPIED, NOR USED FOR ANY OTHER PURPOSE THAN FOR WHICH ITIS SPECIFICALLY FURNISHED WITHOUT THE PRIOR WRITTENCONSENT OF SAID W. W. WHEELER & ASSOCIATES.
R:\1
80
0\1
86
7\1
86
7.0
1_
Lo
we
rB
BD
am
\C
AD
\L
ow
erB
ea
ve
rB
ro
ok_
Alt2
7
-2
4-1
7 0
9:3
3a
m S
co
tt X
RE
FS
:
3700 S. Inca Street | Englewood, CO 80110-3405303-761-4130 | fax 303-761-2802
& ASSOCIATES, INCW. W. WHEELER
Water Resources Engineers
Reference
Sheet No. Drawing No. Title
50.0'
150°
20.0'
10.0'10.0'
20.0'
125.0'
RCC BASIN FLOOREL. 7796.0
RCC
BENC
HEL
. 781
0.0
RCC
BENC
HEL
. 781
0.0
RCC EMERGENCYSPILLWAY CREST
EL. 7740.0
NON-OVERFLOW DAM CRESTEL. 7745.0
UPSTREAM FACEAND DAM AXIS
CHIMNEY SECTION
CONCRETE END SILL
EXCAVATE ROCK BENCHEL. 7836.0
NEW SERVICESPILLWAY CRESTEL. 7837.7
20.0'
NON-OVERFLOW DAM CREST
EL. 7745.0
125.0'
DAM CRESTEL. 7845.0
RCC EMERGENCY SPILLWAY CRESTEL. 7840.0
EL. 7792.0
EL. 7836.0
NEW SERVICESPILLWAY CRESTEL. 7837.7
APPROX. PRE-CONSTRUCTIONGROUND SURFACE
CONTRACTION JOINT(TYP.)
BOTTOM OF CHIMNEYEL. 7815.0
11
12
11
DAM TOEBENEATH
0.5H:1V
0.8H
:1V
Wheeler No.
Sheet No.
Drawing No.
Design
Drawn
Check
Plot Date
Client
C107/24/2017
LOOKOUT MOUNTAIN WATER DISTRICT
YKC
SAA
DTH
1867.01
1 of 3
0
LOWER BEAVER BROOK DAM
ALTERNATIVE 5 - NEW RCC DAMCONCEPTUAL PLAN AND PROFILE
No.
Revis
ions
Date Made Checked Remarks
0 07/01/17 YKC DTH PRELIMINARY CONCEPTUAL DRAWING
20'
AC2
CHIMNEY SECTION
BC2
℄ OUTLET WORKS
℄ OUTLET WORKS
3C2
LIMIT OF EXCAVATION
TURN INPROFILE
ELE
VA
TIO
N (F
EE
T)
℄E
LE
VA
TIO
N (F
EE
T)
1+50
7770
7780
7790
7800
7810
7820
7830
7840
7850
7860
7770
7780
7790
7800
7810
7820
7830
7840
7850
7860
0.020.040.0 0.0 -20.0 -40.0 -60.0 -80.0 -100.0
PRELIMINARY ONLY
NOT FOR
CONSTRUCTION
THIS DRAWING TOGETHER WITH ITS PARENT ELECTRONIC MEDIAFILE IS THE PROPERTY OF W. W. WHEELER & ASSOCIATES, UNLESSOTHERWISE EXCEPTED, OR SUPERSEDED BY WRITTEN AGREEMENTWITH THE CLIENT LISTED IN THE TITLE BLOCK. IT IS FURNISHEDON THE EXPRESS CONDITION THAT IT SHALL NOT BE REPRODUCED,COPIED, NOR USED FOR ANY OTHER PURPOSE THAN FOR WHICH ITIS SPECIFICALLY FURNISHED WITHOUT THE PRIOR WRITTENCONSENT OF SAID W. W. WHEELER & ASSOCIATES.
R:\1
80
0\1
86
7\1
86
7.0
1_
Lo
we
rB
BD
am
\C
AD
\L
ow
erB
ea
ve
rB
ro
ok_
Alt2
7
-2
4-1
7 0
9:3
3a
m S
co
tt X
RE
FS
:
3700 S. Inca Street | Englewood, CO 80110-3405303-761-4130 | fax 303-761-2802
& ASSOCIATES, INCW. W. WHEELER
Water Resources Engineers
Reference
Sheet No. Drawing No. Title
NON-OVERFLOW DAM CREST(BEYOND)
BASIN FLOOREL. 7796.0
APPROX. PRE-CONSTRUCTIONROCKFILL EMBANKMENT
CONCRETE END SILL
38.4'
2.0'20.0'
EL. 7840.0
BOTTOM OF CHIMNEY SECTIONEL. 7815.0
EL. 7845.020.0'
1.0' LEVELING CONCRETE
EL. 7799.0
EL. 7793.0
3' RCC IN BASIN FLOOR
10.8
2C2
1C2
DAM AXIS
18" LOW LEVEL GATE
18" MID LEVEL GATE
TRASH RACK(TYP.)
18" STEEL OUTLET PIPEEXCAVATE 5' IN ROCK TOCOMPETENT FOUNDATION
EL. 7792.0
APPROX. TOP OF BEDROCKEL. 7797± @ MAX. SECTION
RCC
NWS EL. 7837.7
LIMIT OF EXCAVATION
18" PIPE
1.5'
2.0'
EL. 7837.7
EL. 7836±
UPSTREAM FACE
GROUT ENRICHED RCC
1" BEDDING MIX
1.0' (TYP.) 10.8
1.0' (TYP.)
1.0' (TYP.)
11
TYPICAL DETAILUPSTREAM FACING
C21
RCC
10' (TYP.)1.0'
RCC
11
VERTICAL STEP(FORMED)
GROUT ENRICHED RCC
TYPICAL DETAILDOWNSTREAM FACING
C22
TYPICAL SECTIONSERVICE SPILLWAY CREST
C1B
TYPICAL DETAILRCC/ABUTMENT 3
GROUT ENRICHED RCC
1.0' (TYP.)
ROCK ABUTMENT
11
1.0' (TYP.)
NO. 8 DRILLEDROCK ANCHOR
EXCAVATE AS STEEPLYAS POSSIBLE IN ROCK
Wheeler No.
Sheet No.
Drawing No.
Design
Drawn
Check
Plot Date
Client
C207/24/2017
LOOKOUT MOUNTAIN WATER DISTRICT
YKC
SAA
DTH
1867.01
2 of 3
0
LOWER BEAVER BROOK DAMDAM REHABILITATION
ALTERNATIVE 5 - NEW RCC DAMDAM SECTIONS AND DETAILS
No.
Revis
ions
Date Made Checked Remarks
0 07/01/17 YKC DTH PRELIMINARY CONCEPTUAL DRAWING
MAXIMUM SECTIONNEW CONCRETE DAM
C1A
0.5H:1V (ROCK)12" LEVELING CONCRETE
℄ BLANKET GROUTHOLES (TYP.)
℄ GROUT CURTAIN(TYP.)
1+
00
2
+
0
0
2+
77
7820
7820
7825
7825
7830
7830
7835
7835
7840
7840
7805
7805
7810
7810
7815
7815
7800
7
8
0
0
7805
7
8
0
5
7810
7
8
1
0
7
8
1
5
7
8
1
5
7820
7
8
2
0
7
8
2
5
7
8
2
5
7
8
3
0
7
8
3
0
7
8
3
5
7
8
3
5
7
8
4
0
7840
7
8
4
5
7
8
4
5
7850
7
8
5
0
7855
7855
7860
7
8
6
5
7
8
7
0
7
8
7
5
7
8
8
0
7
8
8
5
7
8
9
0
7
8
0
5
7
8
1
0
7
8
1
5
7
8
2
0
7825
7830
7
8
3
5
7840
7
8
4
5
7800
7805
7
8
0
5
7810
7
8
1
0
7815
7815
7820
7820
7825
7825
7830
7
8
3
0
7835
7835
PRELIMINARY ONLY
NOT FOR
CONSTRUCTION
THIS DRAWING TOGETHER WITH ITS PARENT ELECTRONIC MEDIAFILE IS THE PROPERTY OF W. W. WHEELER & ASSOCIATES, UNLESSOTHERWISE EXCEPTED, OR SUPERSEDED BY WRITTEN AGREEMENTWITH THE CLIENT LISTED IN THE TITLE BLOCK. IT IS FURNISHEDON THE EXPRESS CONDITION THAT IT SHALL NOT BE REPRODUCED,COPIED, NOR USED FOR ANY OTHER PURPOSE THAN FOR WHICH ITIS SPECIFICALLY FURNISHED WITHOUT THE PRIOR WRITTENCONSENT OF SAID W. W. WHEELER & ASSOCIATES.
R:\1
80
0\1
86
7\1
86
7.0
1_
Lo
we
rB
BD
am
\C
AD
\L
ow
erB
ea
ve
rB
ro
ok_
Alt2
7
-2
4-1
7 0
9:3
3a
m S
co
tt X
RE
FS
:
3700 S. Inca Street | Englewood, CO 80110-3405303-761-4130 | fax 303-761-2802
& ASSOCIATES, INCW. W. WHEELER
Water Resources Engineers
Reference
Sheet No. Drawing No. Title
UPSTREAM FACEAND DAM AXIS
NEW SERVICESPILLWAY CRESTEL. 7837.7
Wheeler No.
Sheet No.
Drawing No.
Design
Drawn
Check
Plot Date
Client
C307/24/2017
LOOKOUT MOUNTAIN WATER DISTRICT
YKC
SAA
DTH
1867.01
3 of 3
0
LOWER BEAVER BROOK DAMDAM REHABILITATION
ALTERNATIVE 5 - NEW RCC DAMSTAGED EXCAVATION
No.
Revis
ions
Date Made Checked Remarks
0 07/01/17 YKC DTH PRELIMINARY CONCEPTUAL DRAWING
STAGE 1EXCAVATION
STAGE 2EXCAVATION
12
PRE-CONSTRUCTIONGROUND SURFACE
EL. 7815
EL. 7802±
STAGED EXCAVATION OF ROCKFILL EMBANKMENT
STAGE 1 - EXCAVATE DOWN TO BENCH EL. 7815 DURING NEW RCC DAM CONSTRUCTION.USE EXCAVATED ROCKFILL TO PROCESS RCC AGGREGATE. USE ROCKFILL BENCHFOR BATCH PLANT AND STOCKPILE AREA.
STAGE 2 - EXCAVATE RIGHT SIDE DOWN TO STREAM CHANNEL (EL. 7802±). USE 2H:1VPERMANENT SLOPE IN ROCK FILL. MAINTAIN MINIMUM OF 10 FEET FROM NEWOUTLET WORKS INTAKE.
EL. 7815
EL. 7802±
PRE-CONSTRUCTIONGROUND SURFACE
STAGE 1EXCAVATION
STAGE 2EXCAVATION
EXCA
VATE
TO
BENC
HEL
. 781
5(S
TAGE
1) EX
CAVA
TE T
OST
REAM
CHA
NNEL
(STA
GE 2
)
2H:1V
℄ NEW OUTLETWORKS
OUTLINE OFNEW RCC DAM
Attachment 3
Existing Dam Information
Aerial Image and Photos of Existing Site
LOWER BEAVER BROOK DAM PHOTOS
PAGE 1
EXISTING LOWER BEAVER BOOK DAM SITE
Water Treatment Facility
Lower Beaver Brook Dam
Lower Beaver Brook Reservoir
Spillway Crest Control Sill
Beaver Brook
Outlet Tunnel Access Entrance
Outlet Conduit (Approx. Extents)
Outlet Pipe to Water Treatment Facility (Approx. Extents)
LOWER BEAVER BROOK DAM PHOTOS
PAGE 2
Photo 1 – View of Lower Beaver Brook Dam looking left at the dam crest from the left side of the spillway. Photo taken in May 2016.
Photo 2 – View of the downstream slope of Lower Beaver Brook Dam and the spillway discharge channel looking right from near the left abutment. Photo taken in May 2016.
Outlet Tunnel Entrance
Spillway Control Sill Spillway Discharge Channel
LOWER BEAVER BROOK DAM PHOTOS
PAGE 3
Photo 3 – View of the downstream slope of Lower Beaver Brook Dam, the downstream channel, and the Water Treatment Facility located downstream of the left abutment. Photo taken looking left and downstream from the left side of the spillway. Photo taken in May 2016.
Photo 4 – View looking right at the spillway control sill. Photo taken in May 2016.
LOWER BEAVER BROOK DAM PHOTOS
PAGE 4
Photo 5 – View looking downstream at the spillway discharge channel downstream from the spillway control sill. Photo taken in May 2016.
Photo 6 – View of the outlet pipes and control valves in the outlet tunnel looking upstream. Photo taken January 2017.
Attachment 4
1936 Engineering Drawings
Lower Beaver Brook Dam
Page 3
Access/Staging/Stockpile-- Existing Access Road, Plan to clear areas adjacent to the access road to allow for staging and stockpiles(0.53 acres)
New Concrete Dam Construction and Removal of Existing Dam(0.87 acres)
Temporary Staging/Stockpile in the reservoir pool area(2.29 acres)
Temporary Diversion Pipeline from Diversion Dam to Water Treatment Plant Pipeline will be above ground
Inflow Measurement Flume(Permanent)0.01 acres
Temporary Diversion Dam(used during construction toprovide water to the Treatment Plant)(0.03 acres)
Temporary Pool created by the Diversion Dam-- Not planning to remove vegetation in the pool area, temporary inundation of area(0.15 acres)
Temporary Access Disturbance foraccess to construct diversion/flume Some use for Staging/Stockpile (1.55 acres)
q 0 100 200
Feet
R:\
18
00
\18
67
\18
67
.01
_L
ow
erB
BD
am
\GIS
\MX
D\Im
pa
ct_
ma
p_
fie
ld.m
xd
Job. #: 1867.01.01 FIGURE 1
Lower Beaver Brook DamDRAFT Impact Map
NO
VE
MB
ER
20
18
LegendImpact
Permanent
Temporary
DRAFT Info from EROOpen Water
Ordinary High Water Mark
Wetland
Concrete Dam Footprint
DRAFT
Page 4
Lower Beaver Brook Dam (ERO photograph DSC_0579, November 30, 2018)
U.S. Department of Homeland Security Region VIII Denver Federal Center, Building 710 P.O. Box 25267 Denver, CO 80225-0267
www.fema.gov
R8-EHP
March 12, 2019
Karen Kinnear, Executive Secretary Colorado Archaeological Society Tel: 303-917-1528 [email protected] The Lookout Mountain Water District, Clear Creek County, Colorado, has requested funding from the Federal Emergency Management Agency (FEMA) through the Pre-Disaster Mitigation (PDM) grant program for proposed risk reduction spillway and dam safety modifications. The project proposes to replace the existing concrete face rockfill dam with a new concrete gravity dam immediately adjacent to the existing structure. The purpose of the program is to reduce the risks of damage or catastrophic failure from floods and natural disasters in the future. The purpose of this letter is to solicit your input regarding the project’s effects on historic properties and cultural resources. The proposed project is located on private land along Lower Beaver Brook west of the town of Evergreen in Clear Creek County, Colorado (latitude: 39.705958, longitude: 8.589081). The proposed Area of Potential Effect (APE) includes the limits of disturbance from the proposed undertaking, including the construction limits and areas that may be disturbed by grading and staging. The APE includes the cultural resource boundary for a historic structure affected by the project: The Lower Beaver Brook Dam, including the dam footprint and associated reservoir's flood zone. The APE is 5.37 acres. A copy of FEMA’s Section 106 consultation with Colorado State Historic Preservation Officer (SHPO) is attached. As discussed in the attached letter, ERO Resources Corporation (ERO) cultural resource project manager Abigail Sanocki and staff archaeologist Shayleen Ottman conducted a Class III pedestrian survey of the APE to identify and document cultural resources on November 29, 2018. The survey was conducted under ERO's state archaeological survey and testing permit (2018-73810). The file search and pedestrian survey resulted in identification of the Lower Beaver Brook Dam (5CC2566) as a historic property. The structure has no known association with Native American Tribes and given the geology and previous disturbance to the area, the potential for subsurface archaeological remains within the APE is extremely low. The Class III survey of the APE resulted in documentation of Lower Beaver Brook Dam (5CC2566), no other cultural resources were observed. FEMA determined 5CC2566 is eligible for listing in the National Register of Historic Places under Criteria A and C because the dam is associated with significant events and trends associated with early efforts to develop mountain water sources for municipalities on the Rocky Mountain Front Range and Depression-era rural federal undertakings (Criterion A) and the structure is an excellent example of early 20th century concrete-lined rockfill
Lower Beaver Brook Dam March 12, 2019
Page 2
dams and the outflow tunnel and stacked-rock elements exhibit unique aspects of design and engineering (Criterion C). Because the project will require complete removal of the historic dam, the project constitutes an adverse effect under 36 CFR 800.5(d)(2) of the National Historic Preservation Act (NHPA). A Memorandum of Agreement (MOA) is being prepared to address the adverse effect. In accordance with Section 106 of the NHPA, as amended, 36 CFR 800.3(f)(2), FEMA respectfully requests any information you may care to provide regarding historic places in the project area that may be affected by the proposed project. and your interest in participating in the Section 106 consultation process. If you have any questions, please do not hesitate to contact Daniel Jones, FEMA Environmental Specialist by telephone at 303-231-1887 or by email at [email protected].
Sincerely,
Richard Myers
Deputy Regional Environmental Officer
Enclosures: Effects and Eligibility Letter w/ maps and photo
Consultation Letter Colorado Archaeological Society March 4, 2019
Lower Beaver Brook Dam March 12, 2019
Lower Beaver Brook Dam (ERO photograph DSC_0579, November 30, 2018)
U.S. Department of Homeland Security Region VIII Denver Federal Center, Building 710 P.O. Box 25267 Denver, CO 80225-0267
www.fema.gov
R8-EHP
March 12, 2019
Kimball Banks Colorado Council of Professional Archaeologists [email protected] Dear Mr. Banks: The Lookout Mountain Water District, Clear Creek County, Colorado, has requested funding from the Federal Emergency Management Agency (FEMA) through the Pre-Disaster Mitigation (PDM) grant program for proposed risk reduction spillway and dam safety modifications. The project proposes to replace the existing concrete face rockfill dam with a new concrete gravity dam immediately adjacent to the existing structure. The purpose of the program is to reduce the risks of damage or catastrophic failure from floods and natural disasters in the future. The purpose of this letter is to solicit your input regarding the project’s effects on historic properties and cultural resources. The proposed project is located on private land along Lower Beaver Brook west of the town of Evergreen in Clear Creek County, Colorado (latitude: 39.705958, longitude: 8.589081). The proposed Area of Potential Effect (APE) includes the limits of disturbance from the proposed undertaking, including the construction limits and areas that may be disturbed by grading and staging. The APE includes the cultural resource boundary for a historic structure affected by the project: The Lower Beaver Brook Dam, including the dam footprint and associated reservoir's flood zone. The APE is 5.37 acres. A copy of FEMA’s Section 106 consultation with Colorado State Historic Preservation Officer (SHPO) is attached. As discussed in the attached letter, ERO Resources Corporation (ERO) cultural resource project manager Abigail Sanocki and staff archaeologist Shayleen Ottman conducted a Class III pedestrian survey of the APE to identify and document cultural resources on November 29, 2018. The survey was conducted under ERO's state archaeological survey and testing permit (2018-73810). The file search and pedestrian survey resulted in identification of the Lower Beaver Brook Dam (5CC2566) as a historic property. The structure has no known association with Native American Tribes and given the geology and previous disturbance to the area, the potential for subsurface archaeological remains within the APE is extremely low. The Class III survey of the APE resulted in documentation of Lower Beaver Brook Dam (5CC2566), no other cultural resources were observed. FEMA determined 5CC2566 is eligible for listing in the National Register of Historic Places under Criteria A and C because the dam is associated with significant events and trends associated with early efforts to develop mountain water sources for municipalities on the Rocky Mountain Front Range and Depression-era rural federal undertakings
Lower Beaver Brook Dam March 12, 2019
Page 2
(Criterion A) and the structure is an excellent example of early 20th century concrete-lined rockfill dams and the outflow tunnel and stacked-rock elements exhibit unique aspects of design and engineering (Criterion C). Because the project will require complete removal of the historic dam, the project constitutes an adverse effect under 36 CFR 800.5(d)(2) of the National Historic Preservation Act (NHPA). A Memorandum of Agreement (MOA) is being prepared to address the adverse effect. In accordance with Section 106 of the NHPA, as amended, 36 CFR 800.3(f)(2), FEMA respectfully requests any information you may care to provide regarding historic places in the project area that may be affected by the proposed project. and your interest in participating in the Section 106 consultation process. If you have any questions, please do not hesitate to contact Daniel Jones, FEMA Environmental Specialist by telephone at 303-231-1887 or by email at [email protected].
Sincerely,
Richard Myers
Deputy Regional Environmental Officer
Enclosures: Effects and Eligibility Letter w/ maps and photo
Colorado Council of Professional Archaeologists March 4, 2019
Lower Beaver Brook Dam March 12, 2019
Lower Beaver Brook Dam (ERO photograph DSC_0579, November 30, 2018)
U.S. Department of Homeland Security Region VIII Denver Federal Center, Building 710 P.O. Box 25267 Denver, CO 80225-0267
Page 1
R8-EHP
March 12, 2019
Nathan Richie, Director Golden History Museum & Park 923 10th St, Golden, CO 80401 [email protected] Re: Section 106 Determinations of Eligibility and Effect, Risk Reduction Spillway and Dam Safety Modifications at Lower Beaver Brook Dam, Clear Creek County, Colorado. SHPO HC# 72892 Dear Mr. Richie: The Lookout Mountain Water District, Clear Creek County, Colorado, has requested funding from the Federal Emergency Management Agency (FEMA) through the Pre-Disaster Mitigation (PDM) grant program for proposed risk reduction spillway and dam safety modifications. The project proposes to replace the existing concrete face rockfill dam with a new concrete gravity dam immediately adjacent to the existing structure. The purpose of the program is to reduce the risks of damage or catastrophic failure from floods and natural disasters in the future. The purpose of this letter is to solicit your input regarding the project’s effects on historic properties and your interest in participating in the Section 106 consultation process. The proposed project is located on private land along Lower Beaver Brook west of the town of Evergreen in Clear Creek County, Colorado (latitude: 39.705958, longitude: 8.589081). The proposed Area of Potential Effect (APE) includes the limits of disturbance from the proposed undertaking, including the construction limits and areas that may be disturbed by grading and staging. The APE includes the cultural resource boundary for a historic structure affected by the project: The Lower Beaver Brook Dam, including the dam footprint and associated reservoir's flood zone. The APE is 5.37 acres. A copy of FEMA’s Section 106 consultation with Colorado State Historic Preservation Officer (SHPO) is attached. As discussed in the attached letter, ERO Resources Corporation (ERO) cultural resource project manager Abigail Sanocki and staff archaeologist Shayleen Ottman conducted a Class III pedestrian survey of the APE to identify and document cultural resources on November 29, 2018. The survey was conducted under ERO's state archaeological survey and testing permit (2018-73810). The file search and pedestrian survey resulted in identification of the Lower Beaver Brook Dam (5CC2566) as a historic property. The structure has no known association with Native American Tribes and given the geology and previous disturbance to the area, the potential for subsurface archaeological remains within the APE is extremely low.
Lower Beaver Brook Dam March 12, 2019
Page 2
The Class III survey of the APE resulted in documentation of Lower Beaver Brook Dam (5CC2566), no other cultural resources were observed. FEMA determined 5CC2566 is eligible for listing in the National Register of Historic Places under Criteria A and C because the dam is associated with significant events and trends associated with early efforts to develop mountain water sources for municipalities on the Rocky Mountain Front Range and Depression-era rural federal undertakings (Criterion A) and the structure is an excellent example of early 20th century concrete-lined rockfill dams and the outflow tunnel and stacked-rock elements exhibit unique aspects of design and engineering (Criterion C). Because the project will require complete removal of the historic dam, the project constitutes an adverse effect under 36 CFR 800.5(d)(2) of the National Historic Preservation Act (NHPA). A Memorandum of Agreement (MOA) is being prepared to address the adverse effect. In accordance with Section 106 of the NHPA, as amended, 36 CFR 800.3(f)(2), FEMA respectfully requests any information you may care to provide regarding historic places in the project area that may be affected by the proposed project and your interest in participating in the Section 106 consultation process. If you have any questions, please do not hesitate to contact Daniel Jones, FEMA Environmental Specialist by telephone at 303-231-1887 or by email at [email protected].
Sincerely,
Richard Myers
Deputy Regional Environmental Officer
Enclosures: Effects and Eligibility Letter w/ maps and photo
Consultation Letter Colorado Archaeological Society March 4, 2019
Lower Beaver Brook Dam March 12, 2019
Lower Beaver Brook Dam (ERO photograph DSC_0579, November 30, 2018)
Sent via Email March 14, 2019 to: Eastern Shoshone Tribe (Wind River Reservation) Joshua Mann, THPO P.O. Box 538, Fort Washakie, WY 82514 Phone: (o) 307-335-2081 [email protected] Ute Mountain Ute Tribe Terry Knight, Sr., THPO P.O. Box 468, Towaoc, CO 81334 970-564-5727 [email protected] Northern Arapahoe Tribe Devon Oldman, THPO P.O. Box 396, Fort Washakie, WY 82514 307-438-5318 [email protected] Southern Ute Indian Tribe Cassandra Atencio, NAGPRA Coordinator P.O. Box 737 MS#88, Ignacio, CO 81137 970- 563-2989 [email protected] Re: Section 106 Determinations of Eligibility and Effect, Risk Reduction Spillway and Dam Safety Modifications at Lower Beaver Brook Dam, Clear Creek County, Colorado. SHPO HC# 72892 The Lookout Mountain Water District, Clear Creek County, Colorado, has requested funding from the Federal Emergency Management Agency (FEMA) through the Pre-Disaster Mitigation (PDM) grant program for proposed risk reduction spillway and dam safety modifications. The project proposes to replace the existing concrete face rockfill dam with a new concrete gravity dam immediately adjacent to the existing structure. The purpose of the program is to reduce the risks of damage or catastrophic failure from floods and natural disasters in the future. The purpose of this letter is to solicit your input regarding the project’s effects on historic properties and cultural resources. The proposed project is located on private land along Lower Beaver Brook west of the town of Evergreen in Clear Creek County, Colorado (latitude: 39.705958, longitude: 8.589081). The proposed Area of Potential Effect (APE) includes the limits of disturbance from the proposed undertaking, including the construction limits and areas that may be disturbed by grading and staging. The APE includes the cultural resource boundary for a historic structure affected by the project: The Lower Beaver Brook Dam, including the dam footprint and associated reservoir's flood
Page 2
zone. The APE is 5.37 acres. A copy of FEMA’s Section 106 consultation with Colorado State Historic Preservation Officer (SHPO) is attached. ERO Resources Corporation (ERO) conducted a Class III pedestrian survey of the APE to identify and document cultural resources on November 29, 2018. The survey was conducted under ERO's state archaeological survey and testing permit (2018-73810). The file search and pedestrian survey resulted in identification of the Lower Beaver Brook Dam (5CC2566) as a historic property. Because the project will require complete removal of the historic dam, FEMA determined and SHPO concurred the project constitutes an adverse effect under 36 CFR 800.5(d)(2) of the National Historic Preservation Act (NHPA). A Memorandum of Agreement (MOA) is being prepared to address the adverse effect. However, the structure has no known association with Native American Tribes and given the geology and previous disturbance to the area, the potential for subsurface archaeological remains within the APE is extremely low. In accordance with Section 106 of the National Historic Preservation Act, as amended, 36 CFR 800.3(f)(2), FEMA respectfully requests any information you may care to provide regarding any issues or concerns related to tribal properties, properties that may have tribal religious or cultural significance, or historic places in the project area that may be affected by the proposed project. If you have any questions, please do not hesitate to contact Daniel Jones, FEMA Environmental Specialist by telephone at 303-231-1887 or by email at [email protected]. Thank you.
Preserving America’s Heritage
ADVISORY COUNCIL ON HISTORIC PRESERVATION
401 F Street NW, Suite 308 Washington, DC 20001-2637 Phone: 202-517-0200 Fax: 202-517-6381 [email protected] www.achp.gov
Advisory Council on Historic Preservation
Electronic Section 106 Documentation Submittal System (e106) Form MS Word format
Send to: [email protected]
I. Basic information
1. Name of federal agency (If multiple agencies, state them all and indicate whether one is the lead agency): Federal Emergency Management Agency, FEMA Region 8, DFC, Building 710, Box 25267 Denver CO 80225-0267
2. Name of undertaking/project (Include project/permit/application number if applicable):
Lower Beaver Brook Dam - Risk Reduction Spillway and Dam Safety Modifications– Clear Creek CO, SHPO (HC# 72892)
3. Location of undertaking (Indicate city(s), county(s), state(s), land ownership, and whether it would occur on or affect historic properties located on tribal lands):
The proposed project is located on private land along Lower Beaver Brook west of the town of Evergreen in Clear Creek County, Colorado (latitude: 39.705958, longitude: 8.589081). The dam is owned and operated by the Lookout Mountain Water District The proposed project is not located on and will not affect tribal lands.
4. Name and title of federal agency official and contact person for this undertaking, including email address and phone number:
Richard Myers Deputy Regional Environmental Officer FEMA Region VIII Desk: 303-235-4926 Mobile: 720-412-3672
2
5. Purpose of notification. Indicate whether this documentation is to:
This submission is to notify the ACHP of a finding that an undertaking may adversely affect historic properties.
II. Information on the Undertaking*
6. Describe the undertaking and nature of federal involvement (if multiple federal agencies are involved, specify involvement of each):
The project proposes to replace an existing concrete-face rockfill dam with a new concrete gravity dam. The purpose of the program is to reduce the risks of damage or catastrophic failure from floods and natural disasters in the future.
7. Describe the Area of Potential Effects:
The Lower Beaver Brook Dam Area of Potential Effect (APE) includes the limits of disturbance from the proposed undertaking, including the construction limits of the dam footprint and areas that may be disturbed by grading and staging, and the associated reservoir's flood zone. The area of the APE is 5.37 acres. Please refer to the enclosed documents for additional details.
8. Describe steps taken to identify historic properties: ERO Resources Corporation (ERO) cultural resource project manager Abigail Sanocki and staff archaeologist Shayleen Ottman conducted a Class III pedestrian survey of the APE to identify and document cultural resources on November 29, 2018. The survey was conducted under ERO's state archaeological survey and testing permit (2018-73810). The structure has no known association with Native American Tribes and given the geology and previous disturbance to the area, the potential for subsurface archaeological remains within the APE is extremely low.
9. Describe the historic property (or properties) and any National Historic Landmarks within the APE (or attach documentation or provide specific link to this information):
The dam was constructed in 1903 and in 1935 improved using Works Progress Administration funds. The file search and pedestrian survey resulted in identification of the Lower Beaver Brook Dam (5CC2566) as a historic property. FEMA determined 5CC2566 is eligible for listing in the National Register of Historic Places under Criteria A and C because the dam is associated with significant events and trends associated with early efforts to develop mountain water sources for municipalities on the Rocky Mountain Front Range and Depression-era rural federal undertakings (Criterion A) and the structure is an excellent example of early 20th century concrete-
3
lined rockfill dams and the outflow tunnel and stacked-rock elements exhibit unique aspects of design and engineering (Criterion C).
10. Describe the undertaking’s effects on historic properties:
The project will require complete removal of the historic dam (5CC2566). Given the geology and previous disturbance to the area, the potential for subsurface archaeological remains within the APE is extremely low.
11. Explain how this undertaking would adversely affect historic properties (include information on any conditions or future actions known to date to avoid, minimize, or mitigate adverse effects):
Because the project will require complete removal of the historic dam, the project constitutes an adverse effect under 36 CFR 800.5(d)(2) of the National Historic Preservation Act (NHPA). A draft Memorandum of Agreement (MOA) is attached.
12. Provide copies or summaries of the views provided to date by any consulting parties, Indian tribes or Native Hawai’ian organizations, or the public, including any correspondence from the SHPO and/or THPO.
An Environmental Assessment (EA) is being prepared and Sec.106 is included as part of the required public notification process. Contact with Tribes and other interested parties will be initiated following this submittal.
* see Instructions for Completing the ACHP e106 Form
III. Optional Information 13. Please indicate the status of any consultation that has occurred to date. Are there any
consulting parties involved other than the SHPO/THPO? Are there any outstanding or unresolved concerns or issues that the ACHP should know about in deciding whether to participate in consultation?
CO SHPO concurred FEMA’s with Eligibly and Effect determinations on February 19, 2019. Correspondence is attached.
14. Does your agency have a website or website link where the interested public can find out about this project and/or provide comments? Please provide relevant links: Yes, a link will be established at https://www.fema.gov/ upon completion of the draft EA. 15. Is this undertaking considered a “major” or “covered” project listed on the Federal
4
Infrastructure Projects Permitting Dashboard or other federal interagency project tracking system? If so, please provide the link or reference number:
No
The following are attached to this form (check all that apply):
_X__ Section 106 consultation correspondence:
_X__ Maps, photographs, drawings, and/or plans
__X_ Additional historic property information
__X_ Other: Draft MOA
Lower Beaver Brook Dam 1 March 28, 2019 Memorandum of Agreement
MEMORANDUM OF AGREEMENT AMONG THE FEDERAL EMERGENCY MANAGEMENT AGENCY,
COLORADO STATE HISTORIC PRESERVATION OFFICER, THE COLORADO DIVISION OF HOMELAND SECURITY AND
EMERGENCY MANAGEMENT, AND LOOKOUT MOUNTAIN WATER DISTRICT, REGARDING THE
RISK REDUCTION SPILLWAY AND DAM SAFETY MODIFICAITONS AT LOWER BEAVER BROOK DAM PROJECT, CLEAR CREEK COUNTY, COLORADO
WHEREAS, the Federal Emergency Management Agency (FEMA) of the Department of Homeland Security proposes to administer Pre-Disaster Mitigation Program (PDM) funding pursuant to Section 230 of the Robert T. Stafford Disaster Relief and Emergency Assistance Act, P.L. 93-288, as amended, through the State of Colorado Division of Homeland Security (DHSEM) to the Lookout Mountain Water District (LMWD) for the Lower Beaver Brook Dam Replacement Project (Undertaking) to protect public infrastructure and related communities; and WHEREAS, the LMWD applied to FEMA for Pre-Disaster Mitigation Program funding for proposed spillway and dam safety modifications to Lower Beaver Brook Dam; and WHEREAS, FEMA, as the lead Federal agency, has determined that the Project is an Undertaking subject to review under Section 106 of the National Historic Preservation Act (NHPA) (Section 106), 54 U.S.C. § 306108, and its implementing regulations, 36 CFR Part 800; and WHEREAS, the Undertaking has been reviewed in accordance with the executed Statewide Programmatic Agreement between FEMA, Colorado State Historic Preservation Officer (SHPO), and Colorado DHSEM (2014 CO Programmatic Agreement); and WHEREAS, FEMA has defined the Undertaking’s area of potential effects (APE) as the limits of disturbance from the proposed Undertaking, including the construction limits and areas that may be disturbed by access and staging. The APE includes the cultural resource boundary for a historic structure that will be adversely affected by the project demolish and replace the Lower Beaver Brook Dam (5CC2566), which was constructed by the City of Golden, Colorado, in 1903, and improved in 1935 using Works Progress Administration funds; and WHEREAS, FEMA, in consultation with the Colorado SHPO, has determined that the Lower Beaver Brook Dam (5CC2566) is eligible for listing in the National Register of Historic Places (NRHP); and WHEREAS, FEMA has determined that the Undertaking will have an Adverse Effect on 5CC2566, and the SHPO has concurred with this determination in a letter dated February 19, 2019; and WHEREAS, FEMA has invited Colorado DHSEM as the Recipient and the LMWD as Sub-recipient to become signatories to this Memorandum of Agreement (MOA); and
Lower Beaver Brook Dam 2 March 28, 2019 Memorandum of Agreement
WHEREAS, FEMA has notified the Advisory Council on Historic Preservation (ACHP) on March 12, 2019, regarding its intent to prepare a MOA to resolve the Adverse Effect and satisfy its Section 106 responsibilities pursuant to the 2014 CO Programmatic Agreement and 36 CFR Part §800.6 (a)(1), and the ACHP has chosen not to participate, pursuant to 36 CFR §800.6(a)(1)(iii); and WHEREAS, FEMA and the LMWD have accomplished appropriate public outreach through publication of an Environmental Assessment, FEMA and LMWD incorporated comments received from the public into the final project design of the Undertaking; and. WHEREAS, FEMA has coordinated with the City of Golden Historic Preservation Board, a Certified Local Government (CLG), the Golden History Museum, and other interested parties, including the Colorado Council of Professional Archaeologists; and the Colorado Archaeological Society; and WHEREAS, FEMA has carried out appropriate Tribal consultation with the Cheyenne and Arapaho Tribes of Oklahoma, Comanche Nation of Oklahoma, Fort Belknap Indian Community of the Fort Belknap Reservation of Montana, Crow Tribe, Eastern Shoshone Tribe (Wind River Reservation), Northern Arapaho Tribe, Northern Cheyenne Tribe, Paiute Indian Tribe of Utah, Southern Ute Indian Tribe, Ute Indian Tribe (Uintah & Ouray Reservation), and Ute Mountain Ute Tribe regarding the effects of the Undertaking on historic properties; WHEREAS, no substantive comments from the public, interested parties and the Tribes have been received regarding the final project design of the Undertaking; and NOW, THEREFORE, in accordance with the 2014 CO Programmatic Agreement and 36 CFR § 800.6(b)(1)(iv), this MOA is being executed to implement the agreed upon resolution of Adverse Effects. FEMA, SHPO, Colorado DHSEM, and the LWMD agree that the Undertaking shall be implemented in accordance with the following stipulations in order to mitigate the adverse effect of the Undertaking on historic properties:
STIPULATIONS
To the extent of its legal authority and in coordination with the SHPO, DHSEM, and LMWD, FEMA will require that the following measures are implemented in order to mitigate the adverse effect of the Undertaking on historic properties, and in keeping with the timelines described in Part IV - Duration. I. PROFESSIONAL QUALIFICATIONS
A. All tasks will be completed by personnel meeting the professional qualifications outlined in the Secretary of the Interior’s Standards and Guidelines for Archeology and Historic Preservation as stated in 36 CFR Part 61. These qualifications are a condition of the MOA and are determined by FEMA, in consultation with the SHPO.
Lower Beaver Brook Dam 3 March 28, 2019 Memorandum of Agreement
B. All background research, fieldwork, analysis, and reporting tasks will be completed according to specifications consistent with the Secretary of Interior’s Standards and Guidelines for Archeological Documentation and Historical Documentation; Standards and Guidelines.
II. MITIGATION OF ADVERSE EFFECT TO HISTORIC PROPERTIES
A. The LMWD shall contract with a qualified archaeological consulting firm whose personnel meet the professional qualifications outlined in Part I to complete the following mitigation measures prior to project implementation:
1. Conduct thorough background research. Background research shall, at a minimum,
include records held at the Colorado SHPO. The literature review may also include the National Register of Historic Places (NRHP) online database, General Land Office (GLO) plat maps, local historical societies, and other sources and data repositories, as necessary and where appropriate. Background research already conducted by the LMWD may fulfill this Stipulation.
2. Prior to demolition, the LMWD will compile photographic documentation and
maps of site number 5CC2566 per Appendix C of the 2014 CO Programmatic Agreement and prepare historic resource documentation report meeting SHPO Level II documentation standards for site number 5CC2566 for inclusion in the Colorado State Archives where it will be available for public use and reproduction. This will include a comprehensive collection of photographs of significant architectural features and typical construction materials, a site plan, and historic construction plans. A draft of the report will be provided to SHPO for review, with comments to be received within 30 days.
B. The LMWD shall coordinate with FEMA and the Colorado SHPO to design an
educational interpretive plan. The plan may include materials that will be provided to staff at the nearby middle school and high school for developing a curriculum for educating students about water storage and delivery in the local area (Beaver Brook and Clear Creek). The topic of water storage may include historic trends about the construction of dams, risk of flooding, and dam safety engineering. These materials may include photographs or video of the project (before, during, and after) and other media and information from similar projects or topics in Colorado. A draft of the plan will be submitted to SHPO for review, with comments to be received within 30 days.
C. LMWD shall render additional copies of the OAHP Level II documentation for
dissemination to local libraries and historical societies. The report copies will include color copies of the photographs and all report figures except archival quality prints and sleeves of the photographs.
III. POST-REVIEW DISCOVERIES
A. Based on the high level of disturbance within the APE, it is not anticipated that any cultural materials identified during construction will be in primary context and considered significant discoveries requiring longer-term work stoppage for
Lower Beaver Brook Dam 4 March 28, 2019 Memorandum of Agreement
consultation. However, in the event that such a discovery should occur, Work will be halted in the vicinity of the discovery and in the surrounding area where further subsurface remains can reasonably be expected to occur. LMWD will notify FEMA within 24 hours of the discovery. FEMA will consult with SHPO per 36 CFR § 800.6 and Stipulation III(B) of the 2014 CO Programmatic Agreement to develop a mitigation plan.
B. If human remains are discovered under any circumstance, FEMA will ensure that the
provisions of Colorado Revised Statute 24-80-1301-1305 are followed. Ground disturbing work in the immediate vicinity of the remains shall cease immediately and the signatories shall consult to develop a written plan of action to manage the discovery in accordance with the Process for Consultation, Transfer, and Reburial of Culturally Unidentifiable Native American Human Remains and Associated Funerary Objects Originating from Inadvertent Discoveries on Colorado State and Private Lands. After approval of the plan by FEMA, the State, the Town, the Office of the State Archaeologist, Tribes, and the Colorado Commission of Indian Affairs, implementation will proceed. Continuation of work following a discovery will be contingent upon approval by the above parties.
IV. DURATION
Every 12 months following execution of this MOA, the LWMD shall provide FEMA a summary report describing work undertaken pursuant to its terms. Such report shall include any proposed scheduling changes, any problems encountered, and any disputes and objections received in their efforts to carry out the terms of this MOA. If the terms of this MOA have not been implemented within five (5) years of the execution date, then this MOA shall be considered null and void. In such an event, FEMA shall notify the Signatories to this MOA and, if it chooses to continue with the Project, then it shall reinitiate review of and consultation on the Project in accordance with 36 CFR §§ 800.3 through 800.7
V. DISPUTE RESOLUTION
Should any Signatory to this MOA object at any time to any actions proposed or the manner in which the terms of this MOA are implemented, FEMA shall consult with such party to resolve the objection. If FEMA determines that such objection cannot be resolved, FEMA will:
A. Forward all documentation relevant to the dispute, including FEMA’s proposed
resolution, to the ACHP. The ACHP shall provide FEMA with its advice on the resolution of the objection within thirty (30) days of receiving adequate documentation. Prior to reaching a final decision on the dispute, FEMA shall prepare a written response that takes into account any timely advice or comments regarding the dispute from the ACHP and the Signatories and provide them with a copy of this written response. FEMA will then proceed according to its final decision.
B. If the ACHP does not provide its advice regarding the dispute within the thirty-day
time period, FEMA may make a final decision on the dispute and proceed accordingly. Prior to reaching such a final decision, FEMA shall prepare a written response that takes into account any timely comments regarding the dispute from the Signatories to the MOA and provide them and the ACHP with a copy of such written response.
Lower Beaver Brook Dam 5 March 28, 2019 Memorandum of Agreement
C. It will be the responsibility of FEMA to carry out all other actions subject to the terms
of this MOA that are not the subject of the dispute. VI. AMENDMENTS
This MOA may be amended when such an amendment is agreed to in writing by all Signatories. The amendment will be effective on the date a copy signed by all of the Signatories is submitted to the ACHP.
VII. TERMINATION
A. In the event that FEMA does not carry out the terms of this MOA, the Signatories shall
consult to seek amendment to the MOA and proceed in accordance with 36 CFR § 800.6(c)(8).
B. Any signatory to the MOA may terminate this MOA by providing thirty (30) days’
notice to the other parties, provided that the parties shall consult during the period prior to termination to seek agreement on amendments or other actions that would avoid termination. In the event of termination, FEMA shall proceed in accordance with 36 CFR § 800.6(c)(8), execute a new agreement in accordance with § 800.6(c)(1) or request comments of the ACHP under 36 CFR § 800.7(a).
Execution of this MOA by FEMA and Signatories, and implementation of its terms, evidence that FEMA has taken into account the potential adverse effects of the Project on historic properties and has afforded the ACHP an opportunity to comment.
U.S. Department of Homeland Security
Region VIII Denver Federal Center, Building 710 P.O. Box 25267 Denver, CO 80225-0267
January 30, 2019 Drue DeBerry, Acting Field Supervisor U.S. Fish and Wildlife Service Colorado Ecological Services Office 134 Union Blvd, Suite 670 P.O. Box 25486 DFC (MS 65412) Denver, CO 80225 RE: FEMA PDMC-PJ-08-CO-2017-002 Pre-Disaster Mitigation Project: Risk Reduction Spillway and Dam Safety Modifications at Lower Beaver Brook Dear Mr. DeBerry: The U.S. Department of Homeland Security's Federal Emergency Management Agency (FEMA) FEMA is initiating consultation of the above-referenced Risk Reduction Spillway and Dam Safety Modifications at Lower Beaver Brook Dam in Clear Creek County, Colorado. It is proposed that Federal funding through FEMA’s Pre-Disaster Mitigation Grant Program be provided to Lookout Mountain Water District (District), the owner of the Lower Beaver Brook Dam. Lower Beaver Brook Dam is a small, high-hazard potential, concrete-face rockfill dam located in Clear Creek County, Colorado. The Dam was originally constructed in 1903 and has several dam safety deficiencies. The proposed project involves constructing a new concrete gravity dam immediately downstream of the existing dam to address the identified dam safety deficiencies. Additional information on the Project is provided in the following attachments:
1. Project Location Map; 2. Description of the background, proposed conceptual design and preliminary conceptual design
drawings; 3. Aerial image and photographs of the existing Lower Beaver Brook Dam site; 4. The District’s SPWRAP certificate
This project will largely occur within the boundaries of the original project footprint. The District has informed FEMA that a quarter acre area located immediately adjacent to where the western side of the dam structure is secured to the natural rock of the valley, will be new disturbance due to the increased structural strength and capacity of the new dam. This new disturbance area will involve the removal of coniferous trees and native vegetation within the small area. This project scope will also involve temporary access disturbance for a diversion pipeline along the west side of the existing reservoir. This temporary disturbance will involve brush clearing activities in a small area to allow laying of an 8 inch diameter surface pipe. The U.S. Fish and Wildlife Service’s (USFWS) Information for Planning and Conservation (IPaC) website of Threatened and Endangered Species was carefully reviewed on October 30, 2017 to identify any threatened and
endangered species that may occur in the project area. IPaC identified 9 listed species that may be potentially present within the project area: 5 threatened, and 3 endangered, and 1 proposed threatened species. A variety of sources were reviewed to determine if the project area could be appropriate habitat for the identified species, including the USFWS Environmental Conservation Online System (ECOS), USFWS Fact Sheets, USFWS Recovery Plans, and Federal Register
publications. The APE of the project contains no designated Critical Habitat, nor is any adjacent to the project area.
Common Name Latin Name Status Preferred habitat
Potential
for
Occurrence
in Action
Area
Birds
Least tern Epioblasma
brevidens E
Sandbars near rivers; Water-related activities/use in the N. Platte, S. Platte and Laramie River Basins may affect listed species in Nebraska.
Low
Mexican spotted owl Strix occidentalis
lucida T Forested mountains and Canyonlands Moderate
Piping Plover Charadrius
melodus T
Sandbars near rivers; Water-related activities/use in the N. Platte, S. Platte and Laramie River Basins may affect listed species in Nebraska.
Low
Whooping crane Grus americana E
Coastal marshes and estuaries, inland marshes, Water-related activities/use in the N. Platte, S. Platte and Laramie River Basins may affect listed species in Nebraska.
Low
Fishes
Greenback cutthroat trout
Oncorhynchus
clarki stomias T Headwaters of the South Platte and Arkansas
River Low
Pallid sturgeon Scaphirhychus
albus E
Water-related activities/use in the N. Platte, S. Platte and Laramie River Basins may affect listed species in Nebraska.
Low
Flowering Plants
Western prairie fringed orchid
Platanthera
praeclara T
Unplowed prairies and sedge meadows. Water-related activities/use in the N. Platte, S. Platte and Laramie River Basins may affect listed species in Nebraska.
Low
Mammals
Canada Lynx Lynx canadensis T Dense subalpine forest and willow-choked corridors along mountain streams and avalanche chutes.
Low
North American wolverine Gulo gulo luscus PT High elevations where snowy conditions exist
well into the warm season Low
Codes for Legal Status: E = Endangered T = Threatened PT = Proposed Threatened Potential to Occur:
High: Species is known to occur in this area Moderate: Project area has species habitat components but is not known to occur in this area Low: Project area does not have species habitat components or is extirpated from the area Source: (USFWS, 2018) Platte River Species: Five species appear on the Official USFWS IPaC generated Species List with the subtext: Water-related activities/use in the N. Platte, S. Platte and Laramie River Basins may affect listed species in Nebraska. These are Least Tern, Pallid Sturgeon, Piping Plover, Western Prairie Fringed Orchid, and Whooping Crane. The District (the applicant) is a member and remains in good standing with SWRAP and is not planning to expand Lower Beaver Brook Reservoir in the future. The District’s SPWRAP certificate is attached to this document (see attached). Water used for project construction would be delivered from Lower Beaver Brook Reservoir which previously underwent depletions consultation. No new depletions would occur from the project since the reservoir won’t be enlarged. No new South Platte River System depletions would occur as a function of construction water use for the project. Wetland mitigation for the project would be at a 1:1 ratio; thus, wetland mitigation would not increase historical depletions via transpiration. As stated in the Service’s Guidance Regarding Wetland Activities and Platte River Basin Depletions, wetlands that specifically mitigate for wetland losses at another nearby location are not likely to adversely affect federally listed species or their habitat in the Platte River basin (Service 2008). The alternative analysis report for this project created by Wheeler on October 2, 2017 states that Alternative 5 (the preferred alternative, and proposed project scope) mitigates the identified dam safety issues and maintains the current reservoir storage and normal high water line, which should maintain the existing LMWD water treatment facility operations, storage, habitat, and wetlands associated with the reservoir, and will have no additional discharges expected in the downstream floodplain during routine flow conditions. FEMA therefore has made a determination of no effect for the following five species in Nebraska: Least Tern, Pallid Sturgeon, Piping Plover, Western Prairie Fringed Orchid, and Whooping Crane. Mexican spotted owl Forested mountains and Canyonlands are primary habitat for the Mexican spotted owl (USFWS, 2012). Old growth or mature forests dominated by large old trees are used as nesting habitat, and the Mexican spotted owl prefers habitat with 40% or greater canopy cover (USFWS, 2012). On 31 August 2004, the FWS designated approximately 3.5 million ha (8.6 million ac) of critical habitat for the Mexican spotted owl on Federal lands in Arizona, Colorado, New Mexico, and Utah (69 FR 53181). Within the critical habitat boundaries, critical habitat includes only protected and restricted habitats as defined in the original Recovery Plan (USDI FWS 1995). Similarly, the primary constituent elements of critical habitat were listed as those habitat features recognized in the 1995 Recovery Plan as associated with Mexican spotted owl occupancy, as follows:
▪ Primary Constituent Elements Related to Forest Structure:
• A range of tree species, including mixed-conifer, pine-oak, and riparian forest types, composed of different tree sizes reflecting different ages of trees, 30-45% of which are large trees with a trunk diameter of ≥0.3 m (12 in) when measured at 1.4 m (4.5 ft) from the ground;
• A shaded canopy created by the tree branches and foliage covering ≥40% of the ground; and, large, dead trees (i.e., snags) with a trunk diameter of at least
• 0.3 m (12 in) when measured at 1.4 m (4.5 ft) from the ground. ▪ Primary Constituent Elements Related to Maintenance of Adequate Prey Species:
• High volumes of fallen trees and other woody debris; • A wide range of tree and plant species, including hardwoods; and, • Adequate levels of residual plant cover to maintain fruits, seeds, and
allow plant regeneration. Based on the vegetative community (mixed conifer), slope, and percent canopy cover (>40%), primary constituent elements related to forest structure and prey species of the Mexican Spotted owl are present within the vicinity of the project area. It is reasonably foreseeable that if the Mexican spotted owl occurs in or near to the project area, the noise from the construction equipment could cause startle responses in both the Mexican spotted owl and prey species. According to the best data available to our agency it appears that the nearest known nest site for MSO is approximately 30 miles south east of the project site, west of Castle Rock. FEMA has made the determination of may affect, but not likely to
adversely affect for the Mexican Spotted owl. The following best management practices will be employed to mitigate any potential effect to the Mexican spotted owl (USFWS, 2012):
▪ Disturbance activities would be limited to the boundaries of the demarcated subareas.
▪ Activities would take place between the hours of 7:00am and 6:30pm. No
nighttime activities would occur, as this is prime foraging hours for the Mexican spotted owl.
Greenback cutthroat trout: Greenback cutthroat trout only occur in 442 acres of lakes and ponds and 102 miles of stream habitat in the headwaters of the South Platte River and Arkansas River drainages (USFWS, 1998b). After speaking with aquatic biologists at Colorado Parks and Wildlife, as well as a biologist at the USFWS, it has been determined that the project area is not within the known habitat for the green cutthroat trout. Additionally, brown trout have been identified in the waters of the beaver brook dam complex, a species know to prey on greenback cutthroat trout. Based on increasingly low probability of this species presence within the APE, FEMA has determined that the proposed project will have no effect on the green cutthroat trout. Canada Lynx: The lynx lives in North America and Eurasia. Lynx may have disappeared from Colorado by about 1973. Sightings prior to that time were few, scattered throughout mountainous areas of the state. In 1999, an ambitious program of lynx restoration began in the remote San Juan Mountains. By 2005, more than 200 animals had been released, several litters of kittens had been born, and lynx were expanding throughout the high country and occasionally beyond. The lynx is found in dense subalpine forest and willow-choked corridors along mountain streams and avalanche chutes, the home of its favored prey, the snowshoe hare. McKelvey et al. (2000) and Ruediger et al. (2000) suggest areas below 2438m (8000 ft)
represent essentially zero potential habitat for lynx. This elevation cutoff was supported by the locationality data included in the more recent “Predictive Map of Canada Lynx Habitat Use in Colorado” from Jake Ivan et al. as a collaboration between Colorado Parks and Wildlife, National Park Service, and Colorado State University. Of their collected 40,000 lynx locations since 200 within the state, 99% were located above 8000ft of elevation and the small minority that were below this boundary were excluded from the predictive mapping analysis. The elevation of this Risk Reduction Spillway and Dam Safety Modifications at Lower Beaver Brook is 7804 ft (Google Earth). Due to these factors, as well as the scope of work for this project, FEMA has determined that the proposed project will have no effect on the Canada Lynx. North American Wolverine: The primary habitat for the North American wolverine is very cold areas receiving considerable snow such that snow cover persists well into spring (USFWS, Undated(d)). The project area does not contain appropriate habitat required by the North American wolverine. Therefore, FEMA has determined that the proposed project will have no effect on the North American wolverine. Removal of vegetation in the project area has the potential to impact migratory birds and raptors. The proposed actions are subject to compliance with the Migratory Bird Treaty Act (MBTA) and the Bald or Golden Eagle Protection Act (BGEPA). In accordance with US Fish and Wildlife (USFWS) guidelines, the applicant is responsible for obtaining and complying with any necessary permits from USFWS. If active nests are observed in the project area, appropriate USFWS buffer zones and/or seasonal restrictions may be required. See https://www.fws.gov/birds/policies-and-regulations.php. Alternatively, work can be completed outside of the nesting season. Based on the information provided and discussed above, FEMA has made a determination that the proposed project will have “no effect” for the Canada lynx, least tern, whooping crane, greenback cutthroat trout, pallid sturgeon, Ute ladies-tresses, western prairie fringed orchid, and North American wolverine. Additionally, FEMA has made a determination that the proposed project “may affect, not likely to adversely affect” for the Mexican spotted owl. Your concurrence with these determinations is respectfully requested. If you have questions or need additional information, please contact me at (303) 235-4926, [email protected].
Sincerely, Richard Myers Deputy Regional Environmental Officer FEMA Region VIII
References
USFWS. (1990). Interior Population of the Least Tern (Sterna Antillarum) Recovery Plan. Retrieved March 2017, from http://ecos.fws.gov/docs/recovery_plan/900919a.pdf USFWS. (1998a). ESA Consultations Involving Platte River Depletions: Information for Project Proponents in Nebraska on the Platte River Recovery Implementation Program. U.S. Fish and Wildlife Service Mountain-Prairie Region. USFWS. (1998b). Green Cutthroat Trout Recovery Plan. Retrieved March 2017, from http://ecos.fws.gov/docs/recovery_plan/MSO_Recovery_Plan_First_Revision_Dec2012.pdf USFWS. (2012). Mexican Spotted Owl Recovery Plan, First Edition. Retrieved March 2017, from http://ecos.fws.gov/docs/recovery_plan/MSO_Recovery_Plan_First_Revision_Dec2012.pdf USFWS. (2013). Block Clearance. Retrieved March 2017, from Mountain-Prairie Region: https://www.fws.gov/mountain-prairie/species/mammals/preble/BLOCK_CLEARANCE/BLOCKCLEARANCEindex.htm USFWS. (Undated(a)). Whooping Crane (Grus americana). Retrieved March 2017, from Environmental Online Conservation System: http://ecos.fws.gov/ecp0/profile/speciesProfile?spcode=B003 USFWS. (Undated(b)). Pallid Sturgeon (Scaphirhynchus albus). Retrieved March 2017, from Environmental Online Conservation System: http://ecos.fws.gov/ecp0/profile/speciesProfile?spcode=E06X USFWS. (Undated(c)). Western Prairie-fringed Orchid (Platanthera praeclara). Retrieved March 2017, from Environmental Conservation Online System: http://ecos.fws.gov/ecp0/profile/speciesProfile?spcode=Q2YD USFWS. (Undated(d)). North American Wolverine (Gulo gulo luscus). Retrieved March 2017, from Environmental Conservation Online System: http://ecos.fws.gov/ecp0/profile/speciesProfile?sId=5123 USFWS. (2018). Guidance on the recent M-Opinion affecting the Migratory Bird Treaty Act.
Project Area
Prepared for: Lookout MountainWater DistrictFile: 10365 Figure 1.mxd (GS)October 19, 2018 ±
Figure 1Vicinity Map
Lower Beaver Brook Environmental Assessment
Portions of this document include intellectual property of ESRI and its licensors and are used herein under license. Copyright © 2018 ESRI and its licensors. All rights reserved.
0 1,500750Feet
Location
Path
: P:\
1030
0 Pr
ojec
ts\1
0365
Low
er B
eave
r Bro
ok E
A\M
aps\
1036
5 Fi
gure
1.m
xd
Section 14, T4S, R72W; 6th PM
UTM NAD 83: Zone 13N; 464742mE, 4395114mN
Longitude 105.411292°W, Latitude 39.705159°N
USGS Squaw Pass, CO QuadrangleClear Creek County, Colorado
Page 3 of 6 Resource Number: 5CC2566 Temporary Resource Number: 10365-AS01 24. Associated buildings, features, or objects:
Constructed features of the resource include the dam (F1), spillway (F2), and tunnel with associated
waterlines (F3); all historical features constructed during or prior to the 1935-1936 WPA-funded improvements
are contributing to the eligibility of the resource. Modern features within the resource boundary include buried
water lines (F3.3) and associated vents (F3.4 and F3.5) to a water treatment plant located outside the northeast
resource boundary, a Parshall flume in the natural channel of Lower Beaver Brook (F4), and a modern
outbuilding (F5); the modern features are noncontributing to the eligibility of the resource.
F# Name Construction history Contributing
status
1 Dam Originally constructed 1903, tunnel added 1935, jersey
barriers added 2014
Contributing
1.1 Stone stairs Likely part of original 1903 construction, no known
modifications
Contributing
2 Spillway Original 1903 construction, no known modifications Contributing
2.1 Spillway crest sill Original 1903 construction, no known modifications Contributing
2.2 Lower spillway Original 1903 construction, no known modifications Contributing
3 Tunnel 1935 addition, no known/visible modifications Contributing
3.1 Valve house and
tunnel portal
1935 addition, no known/visible modifications Contributing
3.2 Return line to Lower
Beaver Brook
1935 addition, no known/visible modifications Contributing
3.3 Waterline to treatment
plant and Golden
1935 addition; altered during ca. 1990 construction of water
treatment plant.
Noncontributing
3.4 Vent over waterline to
treatment plant
Ca. 1990 construction of water treatment plant. Noncontributing
3.5 Vent over waterline
from treatment plant
Ca. 1990 construction of water treatment plant. Noncontributing
4 Parshall flume Ca. 1990 construction of water treatment plant or later. Noncontributing
5 Outbuilding Ca. 1990 construction of water treatment plant. Noncontributing
IV. ARCHITECTURAL HISTORY
25. Date of Construction: Estimate: Actual: 1903
Source of information: State of Colorado 1907 (Case No. 41340); Carstarphen, Colorado Transcript
November 10, 1904
26. Architect/Engineers: L.R. Hope and Fred C. Carstarphen
Source of information: Carstarphen, Colorado Transcript November 10, 1904
27. Builder/Contractor: R.P. McDonald (Denver), H.T. Quick (Golden), P.O. Unger (Golden)
Source of information: Carstarphen, Colorado Transcript November 10, 1904
28. Original owner: City of Golden
Source of information: Carstarphen, Colorado Transcript November 10, 1904
#F1
5CC2566Beaver Brook Dam & Reservoir
Resource Boundary
# Datum
Feature
Beaver Brook
Area of Potential Effect
100 0 10050 Feet
1:2,200±
For Official Use Only: Disclosure of site locations prohibited (43 CFR 7.18)
Hideaway Cir.
!(
!(
#
F3.5
F3.4
F1
F5F2
F3
F4
F2.2
F3.2
F3.3
F1.1
F3.1
F2.1
5CC2566Beaver Brook Dam & Reservoir
Resource Boundary
# Datum
Feature
Feature 3.3
!( Subfeature
Subfeature
Beaver Brook
Area of Potential Effect
25 0 2512.5 Feet
1:700±
For Official Use Only: Disclosure of site locations prohibited (43 CFR 7.18)
5CC2566 – Overview depicting reservoir and upstream face of dam (F1), view to the north-northeast.
Photo Number: SLR.511 Date: 11.29.2018
5CC2566 – Spillway (F2), spillway crest sill (F2.1) in rear left view and dam (F1) on right, view to the south.
Photo Number: SLR.580 Date: 11.29.2018
5CC2566 – Downstream face of dam (F1), lower spillway (F2.2) in foreground and outbuilding (F5) on right; view to the
south-southwest. Photo Number: SLR.582 Date: 11.29.2018
5CC2566 – Downstream face of dam (F1) showing stone staircase (F1.1), view to the southwest.
Photo Number: SLR.521 Date: 11.29.2018
5CC2566 – Downstream side of spillway crest sill (F2.1), view to the south.
Photo Number: SLR.524 Date: 11.29.2018
5CC2566 – Lower spillway (F2.2) from Lower Beaver Brook, view to the east.
Photo Number: SLR.583 Date: 11.29.2018
5CC2566 – Tunnel portal (F3.1) and outlet pipe to Lower Beaver Brook (F3.2), view to the east.
Photo Number: SLR.547 Date: 11.29.2018
5CC2566 – Tunnel portal (F3.1), view to the east-northeast.
Photo Number: SLR.544 Date: 11.29.2018
5CC2566 – Interior of tunnel (F3), view to the south-southeast.
Photo Number: SLR.539 Date: 11.29.2018
5CC2566 – Overview of downstream face of dam (F1), from left-to-right: outbuilding (F5), lower spillway (F2.2), outflow
pipe into Lower Beaver Brook (F3.2), and tunnel portal (F3.1); view to the northeast. Photo Number: SLR.568 Date: 11.29.2018
Save as PDF
EJSCREEN Report (Version 2018) 1 mile Ring Centered at 39.693243,-105.431636
COLORADO, EPA Region 8 Approximate Population: 92 Input Area (sq. miles): 3.14
Lower Beaver Brook
Selected Variables Percentile in
State Percentile in EPA
Region Percentile in
USA
EJ Indexes EJ Index for Particulate Matter (PM
2.5) 15 15 17
EJ Index for Ozone 5 5 1
EJ Index for NATA* Diesel PM 52 52 47
EJ Index for NATA* Air Toxics Cancer Risk
28 24 22
EJ Index for NATA* Respiratory Hazard Index
40 36 32
EJ Index for Traffic Proximity and Volume
8 6 6
EJ Index for Lead Paint Indicator 14 25 26
EJ Index for Superfund Proximity 4 8 5
EJ Index for RMP Proximity 49 54 39
EJ Index for Hazardous Waste Proximity
44 46 39
EJ Index for Wastewater Discharge Indicator
20 18 7
EJ Index for the Selected Area Compared to All People's Blockgroups in the State/Region/USEJ IndexesPM 2.5OzoneNATA Diesel PMNATA Cancer RiskNATA Respiratory HITraffic ProximityLead Paint IndicatorSuperfund ProximityRMP ProximityHazardous Waste ProximityWastewater Discharge IndicatorPercentile0255075100 State PercentileRegional PercentileUSA Percentile This report shows the values for environmental and demographic indicators and EJSCREEN indexes. It shows environmental and demographic raw data (e.g., the estimated concentration of ozone in the air), and also shows what percentile each raw data value represents. These percentiles provide perspective on how the selected block group or buffer area compares to the entire state, EPA region, or nation. For example, if a given location is at the 95th percentile nationwide, this means that only 5 percent of the US population has a higher block group value than the average person in the location being analyzed. The years for which the data are available, and the methods used, vary across these indicators. Important caveats and uncertainties apply to this screening-level information, so it is essential to understand the limitations on appropriate interpretations and applications of these indicators. Please see EJSCREEN documentation for discussion of these issues before using reports.
Sites reporting to EPA
Superfund NPL 0
Hazardous Waste Treatment, Storage, and Disposal Facilities (TSDF) 0
Selected Variables Valu
e
State Avera
ge
Percentile in State
EPA Regio
n Avera
ge
Percentile in EPA
Region
USA Avera
ge
Percentile in USA
Environmental Indicators Particulate Matter (PM 2.5 in µg/m3) 4.5 6.74 8 6.64 7 9.53 0
Ozone (ppb) 54 51.4 98 48.6 99 42.5 95
NATA* Diesel PM (µg/m3) 0.05
38 0.76
6 6
0.607
<50th 0.93
8 <50th
NATA* Air Toxics Cancer Risk (risk per MM) 14 37 3 30 <50th 40 <50th
NATA* Respiratory Hazard Index 0.39 1.8 4 1.4 <50th 1.8 <50th
Traffic Proximity and Volume (daily traffic
count/distance to road) 190 360 60 250 69 600 61
Lead Paint Indicator (% pre-1960s housing) 0.05
3 0.19 51 0.22 41 0.29 27
Superfund Proximity (site count/km distance) 0.08
9 0.1 63 0.11 67 0.12 68
RMP Proximity (facility count/km distance) 0.03
1 0.61 8 0.61 8 0.72 5
Hazardous Waste Proximity (facility count/km
distance) 0.03
5 0.65 16 0.63 21 4.3 8
Wastewater Discharge Indicator (toxicity-weighted
concentration/m distance) 0.00
76 7.6 57 480 65 30 79
Demographic Indicators Demographic Index 5% 30% 1 27% 1 36% 1
Minority Population 4% 31% 3 24% 9 38% 9
Low Income Population 6% 29% 8 30% 6 34% 6
Linguistically Isolated Population 0% 3% 46 2% 55 4% 44
Population with Less Than High School Education
1% 9% 13 9% 11 13% 5
Population under Age 5 3% 6% 16 7% 12 6% 16
Population over Age 64 16%
13% 73 13% 72 14% 66
*The National-Scale Air Toxics Assessment (NATA) is EPA's ongoing, comprehensive evaluation of air toxics in the United States. EPA developed the NATA to prioritize air toxics, emission sources, and locations of interest for further study. It is important to remember that NATA provides broad estimates of health risks over geographic areas of the country, not definitive risks to specific individuals or locations. More information on the NATA analysis can be found at: https://www.epa.gov/national-air-toxics-assessment.
For additional information, see: www.epa.gov/environmentaljustice
EJSCREEN is a screening tool for pre-decisional use only. It can help identify areas that may warrant additional consideration, analysis, or outreach. It does not provide a basis for decision-making, but it may help identify potential areas of EJ concern. Users should keep in mind that screening tools are subject to substantial uncertainty in their demographic and environmental data, particularly when looking at small geographic areas. Important caveats and uncertainties apply to this screening-level information, so it is essential to understand the limitations on appropriate interpretations and applications of these indicators. Please see EJSCREEN documentation for discussion of these issues before using reports. This screening tool does not provide data on every environmental impact and demographic factor that may be relevant to a particular location. EJSCREEN outputs should be supplemented with additional information and local knowledge before taking any action to address potential EJ concerns.
APPENDIX D
EIGHT-STEP DECISION-MAKING PROCESS