6B - Goose Creek/Cottonwood Pond draft pland for ecosystem restoration
CITY OF BOULDER
INFORMATION ITEM FOR:
ENVIRONMENTAL ADVISORY BOARD - August 4, 2010
TRANSPORTATION ADVISORY BOARD - August 9, 2010
WATER RESOURCES ADVISORY BOARD - August 16, 2010
PLANNING BOARD - August 19, 2010
PARKS AND RECREATION ADVISORY BOARD - August 23, 2010
OPEN SPACE BOARD OF TRUSTEES - August 25, 2010
GREENWAYS ADVISORY COMMITTEE AGENDA ITEM
MEETING DATE: August 31, 2010
SUBJECT: Draft Plans for Ecosystem Restoration of South Goose Creek and Cottonwood
Pond
REQUESTING DEPARTMENT:
Anne Noble - Greenways Coordinator, Public Works Utilities
Eric Fairlee - Natural Resources Specialist Ecological Systems, Open Space and Mountain
Parks
PURPOSE: Draft Plans for Ecosystem Restoration of South Goose Creek and Cottonwood
Pond are being provided by the U.S, Army Corps of Engineer to board members as an
information item. If you have questions on this material, please contact Eric Fairlee at 303-
413-7647 or FairleeE bouldercolorado.gov
BACKGROUND: The Goose Creek Restoration project received funding from the Federal
Government allowing the Corps of Engineers to begin work on a feasibility study for restoring
Goose Creek downstream of Foothills Parkway to the confluence with Boulder Creek through
the Cottonwood Ponds. Based on community feedback received in 2007, a conceptual
alternative was chosen for the final Feasibility Report. In 2008, the Corps completed the
existing conditions section of the Feasibility Study which ensures NEPA compliance. The
alternatives will be ranked by habitat function and measureable environmental benefits in
order to prepare for selection of the best alternative. During 2009 a new alternative was
identified for Cottonwood Pond, which involves converting the pond to wetlands. A
conceptual plan of this alternative is being developed for public review and consideration. It
is anticipated that the feasibility study will be completed in 2010 and an agreement for design
and implementation will be signed in 2011.
GREENWAYS ADVISORY COMMITTEE ACTION REQUESTED:
Feedback on the proposed plans is requested from the Greenways Advisory.
AGENDA ITEM # , PAGE [
GOOSE CREEK AT BOULDER, COLORADO
SECTION 206 ECOSYSTEM RESTORATION FEASIBILITY STUDY
PROGRESS REPORT -Executive Summary August 2010
The alternatives for the restoration of South Goose Creek have been largely completed.
A hazardous and toxic waste analysis was done for the project site and no problems were found.
In 2009, it was decided to explore the possibility of restoring Cottonwood Pond as a wetland,
with much less open water. This task is also largely completed. Alternatives, their approximate
costs and ecosystem outputs have been defined in draft form.
Tasks that lie ahead during the remainder of 2010 include incremental comparison of
restoration alternatives and the proposal of the best plan or plans. The draft feasibility report and
technical appendices will also be submitted for internal review within the Omaha District and
within the City of Boulder. Appropriate design concept drawings have been prepared for
inclusion in the report and for public involvement meetings.
Once the concept design has been examined by the City, the public and the Omaha
District, it will be prepared for review by the Corps Northwestern Division. This is anticipated to
take place this winter. The result of the review will be the recommended plan for ecosystem
restoration. A final public meeting will be held in Boulder on this recommended plan, likely in
the spring of 2011.
During 2011, a Project Partnering Agreement (PPA) will be prepared to cover the Plans
and Specifications and Construction phases. This will be jointly prepared and negotiated by the
District and the City of Boulder. It is estimated that the final report and the PPA will be sent up
to Northwestern Division in early summer 2011 for approval. Requests for funding of the
Design and Implementation have been submitted in previous years for 2010 and will be
resubmitted through the following 2 years to complete the project.
Goose Creek, Boulder CO, Section 206 Ecosystem Restoration
Executive Summary & Formulation offllternatives AGENDA ITEM #~~e PAGE
GOOSE CREEK AT BOULDER, COLORADO
SECTION 206 ECOSYSTEM RESTORATION FEASIBILITY STUDY
FORMULATION OF RESTORATION ALTERNATIVES
The restoration alternatives were formulated on the basis of project reaches. Initially the
Project Development Team (PDT) came up with as many as 8 reaches. During the formulation
process, the reaches were gradually reduced to 4 reaches with similar alternatives and problem
solving methods. One of the remaining 4 reaches, the Transit Village reach, was not
incorporated into this restoration effort after careful consideration.
Each alternative would, to varying degrees, provide better connectivity for the stream to
the floodplain, in-stream habitat, riparian vegetation, wildlife habitat and wetland health. Given
the necessity to protect property and infrastructure from channel erosion, it was decided that
almost all of the existing features would be left in place, but "softened." Restoration alternatives
have been formulated for comparison prior to the selection of an ecosystem restoration plan.
Each alternative would present a unique combination of restoration outputs and economic cost.
An overview of the restoration alternatives for the project reaches can be summarized as follows:
• South Goose Creek Restoration (Reach 1). This is the upper South Goose Reach from
Foothills Parkway to Reynolds Corner. It is characterized by urbanization and tight
boundaries of roads and developed businesses properties.
o Alternative 1: Enhance Reach 1 of the existing stream channel by removing
invasive species and establishing a new, natural streamside corridor by increasing
the quantity and quality small wetlands and their connectivity with the stream.
• South Goose Creek Restoration (Reach 2). This is the lower reach of South Goose
Creek from Reynolds Corner to Cottonwood Pond. It includes the existing wetland at the
confluence of North and South Goose Creek, with the lower boundary being the bike trail
separating that wetland from Cottonwood Pond. This reach is less bounded on the right
bank than Reach 1.
o Alternative 1: Enhance Reach 2 of the existing stream channel by removing
invasive species and establishing a new, natural streamside corridor by increasing
the quantity and quality small wetlands and their connectivity with the stream.
o Alternative 2: Move existing bike trail to the south; excavate a new, meandering
channel and a wide floodplain bench to the south to enlarge riparian habitat and
the buffer zone.
• Cottonwood Pond (Reach 3). This includes Cottonwood Pond and surrounding low
banks between the bike trail and Boulder Creek.
o Alternative 1: Fill portion to expand existing wetland in North side of the pond,
and portions of the shoreline to create diverse wetland edge community. Improve
fish habitat in remainder of lake, remove exotic species, establish native
vegetation.
Goose Creek, Boulder CO, Section 206 Ecosystem Restoration
Executive Summary & Formulation of Alternatives
AGENDA fl'EM #W-6 , PACE ~J
o Alternative 2: Recreate the pre-development riparian ecosystem. Decrease pond
depth to create wetland. Excavate shallow meandering stream and other riparian
features, and establish native wetland and riparian vegetation.
ALTERNATIVE SUMMARIES
SOUTH GOOSE CREEK (REACH 1), ALTERNATIVE 1
Reach 1, Alternative 1, consists of approximately 5.55 acres. The primary measures
include riparian zone improvement, construction of wetlands at outfalls, removal of selected
boulders, removal of exotic trees and installation of wildlife migration structures under road
crossings.
Much of this reach is planted with Kentucky bluegrass or other ornamental/lawn grasses.
The primary re-vegetation goal is to replace the non-native lawn grasses with a native mix of
riparian and prairie species to create an effective restored riparian corridor along Goose Creek
that connects with other restored reaches of Goose Creek and the riparian corridor along Boulder
Creek. Specific stream-side plantings will take advantage of low channel backwater areas and
outfall zones to provide greater diversity. There may be opportunities in Reach 1 to remove
select boulders along the low flow channel and create additional meander and backwater areas
adjacent to the flowing stream. The concrete weirs (instream rock/grade structures) and
associated boulder fields will be retained but will be covered with vegetation.
SOUTH GOOSE CREEK (REACH 2), ALTERNATIVE 1
Reach 2, Alternative 1 consists of approximately 1.71 acres. The primary measures
include riparian zone improvement, construction of wetlands at outfalls, removal of selected
boulders and removal of exotic plant species.
This area was also planted with some ornamental/lawn grasses, but also includes poor
quality upland vegetation, which is a mixture of native and invasive species. This alternative
would retain the existing alignment of the channel as well as the existing bike trail, but similar to
Reach 1, focus on riparian zone improvement, opportunities to create backwater and wetland
areas (outfalls, boulder removal) and cover grade structures and boulder fields with vegetation.
SOUTH GOOSE CREEK (REACH 2), ALTERNATIVE 2
This alternative consists of approximately 4.14 acres. The central restoration theme for
this reach entails moving the existing bike trail to the south (further from the right bank of South
Goose Creek), and excavating a new, meandering channel with a wide right bank floodplain
bench to the south. This will also increase the low water channel stream length by adding
sinuosity. Grading up to the bike trail will allow several zones of vegetation establishment,
including wetlands and transitional wetland/prairie, upland prairie and wooded riparian areas.
Goose Creek, Boulder Co, Section 206 Ecosystem Restoration
Executive Summary & Formulation of Alternatives
AGENDA ITEM ~ , PAGE
Near Reynolds Corner on the right descending bank is an outlet area that releases waters
high in iron, which causes the stream at that point to be stained orange. Creating a wetland or
transition zone at this point will assist in absorption before the waters reach the stream. On
higher terraces, establishing a riparian buffer area of dense willows and other woody vegetation
will help prevent establishment by invasive species such as Russian olive. Selection of native
plants will be screened to ensure that the selected plant species are not excessive in height or
rigidity in order to not greatly increase channel roughness for flood conveyance. All grade
control structures and boulder fields would be left intact and covered with vegetation, with the
exception of the grade control weir immediately above the confluence of North and South Goose
Creek, where the right bank portion of the weir could be removed and the boulders used
elsewhere on the project. Additional restoration features include riparian zone improvement,
construction of wetlands at outfalls, removal of selected boulders and the removal of exotic plant
species.
COTTONWOOD POND (REACH 3), ALTERNATIVE I
Cottonwood Pond, Alternative 1, impacts approximately 10.28 acres, 7 acres of open
water and 3.28 acres of edge habitat. The presence of exotic and invasive species, primarily
Eurasian Milfoil, Russian olive and Brome greatly reduces the habitat quality within this area,
limiting wildlife usage. Limited depth and shoreline variation also marginally limit wildlife
usage and overall vegetation protection for aquatic species. The vegetation present is of limited
value due to lack of diversity. This alternative focuses on improving the diversity of habitat and
vegetation of the pond.
Within the Cottonwood Pond project area there exists an opportunity to create a diverse
wetland complex ranging from open water and shallow water marsh to cottonwood riparian
buffer. Proposed restoration measures include filling in a portion of the North end of the pond to
expand the existing wetland at that location, filling and regrading of the shoreline for additional
wetland diversity with native vegetation plantings, installation of fish habitat and the removal of
exotic and invasive species. The area bordering Cottonwood Pond to the south and east contains
a large quantity of invasive Russian olive and crack willow trees. This area can be restored to a
greater density of cottonwoods with native understory.
COTTONWOOD POND (REACH 3), ALTERNATIVE 2
The primary restoration feature for this alternative is to restore this former gravel pit to
the riparian ecosystem that existed early in the 20ffi century. Aerial photos taken in 1937, a time
when the channel was still sinuous, show an abundance of pools of unknown depth and oxbow
channels as Goose Creek entered the flood plain of Boulder Creek. This alternative involves
decreasing the pond depth to create wetland, involving 10.28 acres. Restoring this area will be
done by dewatering the pond and filling in much of its area, excavating a meandering channel,
establishing wetland and transitional plantings and removing exotic and invasive species.
Goose Creek, Boulder CO, Section 206 Ecosystem Restoration
Executive Summary & Formulation of Alternatives
AGENDA ITEM #--Vl- 8, PAS !S7-
The new channel would mimic the pattern/amplitude of the historic channel. Other
features will include a more shallow remnant channel opposing the stream pattern, and deeper
remnant oxbow ponds. In addition, large stands of cottonwood and willows would be planted to
re-establish cottonwood wetland areas similar to historic conditions bordering the creek. The
area bordering Cottonwood Pond to the south and east contains a large quantity of invasive
Russian olive and crack willow trees. This area can be restored to a greater density of
cottonwoods with native understory.
Goose Creek, Boulder CO, Section 206 Ecosystem Restoration
Executive Summary & Formulation of4lternatives
AGENDA I *FM #5T--8 , PAGE
- ~ _ ,r. ~ .Y'•,_~i-~ 'l1~.. alp+~ 1
~ t 7 1 ~ CldGooseCrees.,henielir n.iltyaf _j
' j.' ! • ltte new Cotton cod?cid .w , 'S
. ~~.z it .i • a~
I 'ry.+l V ~I rr 0
Ica
AGENDA ITEM #-4f , PAGE
it-; a.-_ _ GoO-~rs~ r-
Creek C
' • F Section 206 Ecosystem Restoration , .
ar . ` Reach 1 Concept
rw," May 2010
t Awes noes are potential areal f Y -
wrmre V,w oou'd rsrrwrr 1.3 •rii►r i " - -
y r a
bvr+Ws re and try
to 186 *.to a
r bwsr woWd of mk+dwhrbl, y.L r
r { polooLg: hand planUseed(tttme
{ am just sample areas, we'd * _ _ its
t dabrmloe true plscorrwnl at a 1719
lator
71
CS 7twho arum are pmareas r >
,4 1 ` , i i r +-r~r 'L t.~ 4i whom wo could remawsnwve 1.3
ti h tiovkore one by to /adNbb a w t
Thla area (pdno actor, both ache - lover wsUand or OcrahoWal :
weF) has a IN of rwfno Rlanu pdsrawy hood pkmt7saad (thaw - a
meshnp hove o.p, short muolarde. . t are just ample areas, we'd -
~r~ - bufleb pros: t) omW easily wad (na determine true pleaomeat at o
over to rojuwnata ` r►. letar firm);
Estshlnh pralnsVen Uw met
adf easrd to desk, both sides
=both Iwtvas'prdrfo• area
r ; t q*t .1 , • WontiUed both skos of creek) is 4
ooatplote(y o>Sourhwn-rutkw; t)
yr - However; radar than scope, o) r4 h.~
too,
diseN or b) ddil seadula
Lc .
r ~a _ *G
l - d owmaad by bealipmd.rvl -i It
. r Y rrwdtad: 2) WIII a'IPra WrO ll rutted 7r
t low bastes IKV t~ t
,Nl t
r_= R - Ripaaen arvubwtre-
- tJ P • Prattle (uplvd huRerl
I 1 Prr n wet PraHe rwwdan sex
u T
~ Leave ock sbuatures, .
asbblhh uansltkrVwolmnd ~n
tw _ - - - edge. Add sell, ermkn central _ 7 D E - Erne pl -
_ r bwmio.l Dwro warmo , not Wld r " ( o a op.a...r> 3a
Mesh) f. ~ o ar a sore Tres
Efts laft
l f - IY - trenski MVOtWW cep. Trowz E7mllmz
k - Pobntlel Imo ~ '
r r renwYel, aslabllah
wpows
P!T = Wet Prairie/Transition mix - Mix of prairie cordgrass, switchgrass, select sedges e.g. Nebraska sedge;
These areas will be in the saturated/slough areas that exist adjacent to the channel; select boulders will
be removed to provide more variation.
P = Prairie/upland buffer - Primarily buffalo grass, blue grama and western wheatgrass will replace existing sod
AGENDA ITEM 9 , PAGE
k T
Goose Creek
Section 206 Ecosystem Restoration `
I _ t>> Reach 1 Concept - Continued
lr[ May 2010
7faw arum am pctwrllel auras
Creels wstlarrda al vdels ws cook! -rx- 1.3
outfalls (emergent & - boulders and by to fadllleu a Plan) over tress rack r -
tmnsAWJwetlend edge; leworwallend or mkrdebhal; aWaWres; establish
Minor grading, nend gressm soother, Add sal.
potamlalty hww pla"Usoad (thee -k. mood bl kal
PldngSaad sib _ y em }usl aempls ernes, we'd firenay; Ug+I mesh) 4,&4JJW ,..ti ' Alk-
ddormine wo plsownent at a
S ~1 A
later drte)' .R {
Establish pre~flPTlailarUarl mix' Nw~ ON
adJecanl W nook, both Was 2
e0. Model woe wnem
bavWore were movod;
nlao Orsbm mkxahaDllat
socials
r" This area (whole 'proira' area D R = wooden aivubaNasa
'L. WonlHlud, both sides of creek) )e
mmtlolely mmbrlrron-nelhn; i) ♦ ~ ~ P ° Freels (wtarb btdru)
.Y ` HOYM4or, fags! than erxape, a) O P(r ° wet Prakisn'randemn mix
awtaWw dlsoing w b) drQl aaedlfy !=IT ° Tra-b A wWerf W p
S q rsoW by boalfprodical
a, medlod; 2) W11 also plant hurtled - E = FJnerpant
- low bastes O =Open wooer > 38'
177-n OT a Bia Trel
PIT = Wet Praide/Transition mix - Mix of prairie cordgrass, switchgrass, select sedges e.g. Nebraska sedge;
These areas will be in the saturated/slough areas that exist adjacent to the channel; select boulders will
be removed on the right descending bank to provide more variation.
UftJ
P = Prairie/upland buffer - Primarily buffalo grass, blue grama and western wheatgrass will replace existing sod 1 Str
AGENDA ITEM # 8 , PAGE,,
. .,;~t Goose Creek
Section 206 Ecosystem Restoration
Reach 1 Concept - Continued
Thew ways pro poWntW o{aaa This woo (vnrde'ptzJW area -
- ' where we amid romow 1J / ldo.Wlad. both Mdo. of cr ak) I. May 2010 "
E', _ acuMOn WA Ly to L361410 a mnplobly aw4rAh nw w; 1)
1 rowel weiiand W miavaNLW: HWWM, radW VW Swap., n)
- F _ -na* hw ponwow (uwao oon.lcwrd" w b) elifl wading
uwu wNW We at rA wo oat eemoe w+ , we'd 6 o maw by bewp aalui 4W f 'm y
_ auffalla (omsryaM 6 dolsrtnkw Uue plaoamanl nt s m OC od; 2) Wiz also pow limtod _
tnrak0r6l"O.M edge; IeUr Urns); row bGnhoa ! - ,z
Miner grwhp, hand par`
or awed
GW 43W
P over plaea rocs,
e : asta"
- _ ~ I-~ flreame a oGrr, Idd aol, _
- maim mrWd_tlgeul 4+wv
- - - y ~ - er~y, r>ol tlPa mash)
r x f
ple-~t ovor Ir w r - C
ewchlrm; mbhllM ~
T wawa w tithe; Add aoB,
/ anlpn mead t+eNM (warp F-tiao4sil PakiaNansilnn mM '
! piudy: rwr pp/it rrran) w}ocom to Soak, bath atlas a n - Fd don a+-ba Vs
, - ` ~ ~P-Prehb (aPWrtl eras)
Plf • We PrW Wf,wdu- mx
f ~ ~ T e Tran,MaVwe.rd adp
. E e Emepare
o - open water- 36'
DaT-ebe Trw
PfT = Wet Prairie/Transition mix - Mix of prairie cwrdgrass, switchgrass, select sedges e.g. Nebraska sedge; a.., l
These areas will be in the saturated/slough areas that exist adjacent to the channel; select boulders will
be removed on the right descending bank to provide more variation. r , f 1] •
P = Prairie/upland buffer - Primarily buffalo grass, blue grama and western wheatgrass will replace existing sod o
~.Awj~ y
AGENDA ITEM it J , PAGE l0
Goose Creek Create wallorWa at
nde at .
Section 206 Ecosystem Restoration outid), fomerwt d
troesidontwolland edge,
Reach 2, Alt. 2 Concept This am(whole •proldo•arm handpmilmed ~
tr•s~' Idontillad, bolh aides of 1)
May 2010 RoUror than mope, a) consider - Renew ma)odly of rcdrs IIFF
. dladng ar b) drill sodding 6 r x ass olsowham on proled; yt<- 'r
ovorsead by hesUprmtiml Plant over romokurtg rack
metlwd; 2) Will des plant limited ` rock eWdure,; establish
low bushes _ grasses or othar, Add self
& oreaion mrkWd bla"
fhb Imo h) no tlghf
' R
Y; rt r
: 1, ~ 1 ~ '~r ;:t'
` Crash(omo , yTT'r .{e"- ~ ~
ouddb (ontorp,nlat8 - N -
fy - tmnsdbnMvllwtd Ocilla; F .,Plard cues lnew rook
hand p)onUwod skuduroa; establish 'i
- Yra,oes or odter r .6 , i
sa 'ill
'
..SAY
tr - - t E,ledlah nporian trp,rnltb~vil ~
YV - - trodehnrb zc+w
f; $
E,IaWish proifloltrapldan rNs .
adownt to arook, bdh Was, can
FaleW4h
sstsM outward on soulh We of °
lmnilda Establish arse R=Rlp,d&1 /irubartreas
{ tf Y - 1 Reek l l P = Praha (u*m ba")
Now bike blkotreb arrsnt
Pfi - Wal PlatrlelirazWtlGn rMk
'd'`~?,rr4.; - _ 'K' ~T>•7nrulsvJ,NSargaCee
t FEW!- a f_. f ♦ F D E- Enrrpent
In this reach all boulders on the right descending bank will be removed, and the floodplain to the right bank will be 11111111111111111O'OW'"°ta 38'
excavated to allow variations of saturation and grading into upland prairie and small shrubs. Primarily buffalo grass, blue tr ' ti °BT=Bee T.1
grama and western wheatgrass will replace existing sod. Emergent and wet areas should be limited to saturated soils
with isolated pockets of shallow water (0-6"). Riparian shrubs will be limited to those that can do well in direct sun e.g.
sandbar willow, indigobush leadplant, western chokecherry, wild plum, peachleaf willow. Invasive plants will be removed
(RCG, russian olive).
AGENDA ITEM #-i~~- g r PAGE 1
Om.,,
^a 7 ~r;e
4rr~~ •~~wa ~
Fill ourmal lake to maato i
epos rlor'iurvsr F`
sucrouadad by wallarftls
{p• ..,,td R '-,.i ~y r, (shallow water Ie .
t f •1~ ~1 9. J .F n 1 t
14
.~[)ixn ftcrT ,4..
1 i 1•:'"f'oWdIaIW FAX V, 1I"
xG
_ 1\ht Pia~l ~RfBRII Iltl I1.lI`41
u° 6Z,n:.111urSlitfi.e
1'y u w• r' ~ Praan pa"JnJi
4 a~ Crwck H'iwn Htnrrv.l
e w' , tS ,°:v,enrood Hunan zoM
o '^~.j Ilerm Hlnrw~gt-O~ntl"w
~ I Aac~blklulEn Cr I
Nr inb'Shrub Ni iii e
_ Romow crash wlbwet 1_ ~ Mallnra Nati'j Suucrlm
' 1,r, ~.'~'i•.♦ Eotablfsh aobarsvod ww 41 WOA nA k'4..I cAruaure
,aa1 - Mlknvlih.:ndantay zi
eons J,~ ~ Dn Eklt
Ummitmv sip,
AGENDA rmm ~ , PAGE 1 2.
~.~C Y ~ r1k i ,
r, •'7 -
Wit Pro4en aaouun 11 6^ Co
absv Wm~ Si~6oc
j . +r Ren®m Saram Chzmm L d l."
! _ -~s•:~ Mevwwwd Vxluw't~-fib'
! Cornwasvwad71~5tbvr R~erue
.y:,d _-F ■ %aoc (paclabb alvnr.sacunl
Pr lm(Upt:md(iLlt~r;
tit
1 Crack't1 iDww Rcn w"t'
. r~ l,ottonwwcdkgv.Ymc
t l P 1 ! berm Renwti Ovartlaw
Ana b Boulder C t.
iw RamdSMaF Plamiwla
~ 9} A
. iw,p .PranLe nP9A~F
b R Mallard Nam= Sawwk-
~y %4 d nAel Mcamg4nwnm
. _ ~ Bat Box
m
l~~