SUMMARY OF ENVIRONMENTAL MITIGATION SCOPING MEETING
CHATFIELD STORAGE REALLOCATION STUDY
SUITE 1010, 143 UNION BOULEVARD, LAKEWOOD, COLORADO
9:30 AM – 12:15 PM, MONDAY, JUNE 4, 2007
SCOPING MEETING ATTENDEES
Susan Linner, US Fish and Wildlife Service, 303-236-4774, Susan_Linner@fws.gov.
Pete Plage, US Fish and Wildlife Service, 303-236-4750, Peter_Plage@fws.gov.
Paul Winkle, CO Division of Wildlife, 303-291-7232, paul.winkle@state.co.us.
Lance Carpenter, CO Division of Wildlife, 303-291-7277, lance.carpenter@state.co.us.
Matt Martinez, CO Division of Wildlife, 303-291-7141, matt.martinez@state.co.us.
David Giger, CO State Parks, 303-866-3203 ext 331, david.giger@state.co.us.
*Brad Buckner, CO State Parks, 303-791-7275, brad.buckner@state.co.us.
*Ken Brink Jr., CO State Parks, 303-791-7275, ken.brink@co.state.us.
*Rick McLoud, Centennial Water and Sanitation District, 303-791-0430,
rmcloud@highlandsranch.org.
Katie Fendel, Leonard Rice Engineers/City of Brighton, 303-432-2507,
fendel@lrcwe.com.
Larry Vickerman, Denver Botanic Gardens, 303-491-9217,
vickerml@botanicgardens.org.
*Ann Bonnell, Audubon Society of Greater Denver, 303-979-6211, abonnell@juno.com.
Kent Wiley, Audubon Society of Greater Denver, 719-593-1381, wileysk1@msn.com.
*Gary Drendel, Tetra Tech, 303-980-3546, gary.drendel@tteci.com.
Thomas Ryon, Ottertail Environmental, 303-858-8350, tryon@ottertail.us.
*Fred Rios, US Army Corps of Engineers-Tri Lakes Office, 303-979-4120,
alfredo.a.rios@usace.army.mil.
Margaret Langworthy, US Army Corps of Engineers-CO Regulatory Office, 303-9794120, margaret.k.langworthy@usace.army.mil.
*Joel Knofczynski, US Army Corps of Engineers-Omaha, 402-221-4580,
joel.d.knofczynski@usace.army.mil.
*Betty Peake, US Army Corps of Engineers-Omaha, 402-221-4474,
elizabeth.b.peake@usace.army.mil.
*Also participated in visiting potential mitigation sites, 1:30-4:20 pm.
INTRODUCTION AND MEETING OBJECTIVES
Betty Peake, NEPA Coordinator, stated that the Planning Aid Letter prepared by
the US Fish and Wildlife Service February 16, 2006 (previously provided by email to all
attendees) indicated that the amount of mitigation required for the Chatfield storage
reallocation action alternatives may be extensive. Tetra Tech recently updated the
acreage of Preble’s meadow jumping mouse (Zapus hudsonius preblei) habitat, wetlands,
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and migratory bird habitat impacted at the Chatfield project by the no-action alternative,
the 20,600 AF storage reallocation alternative, and the 7,700 AF storage reallocation
alternative. She said that the objectives of this scoping meeting were 1) to present
information quantifying the extent of these impacts and 2) to have as many potential
onsite and off-site mitigation options as possible identified by Tetra Tech, the Corps, and
other attendees. During the afternoon, Fred Rios and Rick McLoud would guide any
interested attendees in viewing a number of these potential mitigation sites. These
mitigation options would be explored in further detail in future meetings, with the goal of
outlining a conceptual mitigation plan within a few months. Group members then
introduced themselves.
SURVEYS OF BIRDS AND HABITATS
Gary Drendel, Project Manager for contractor Tetra Tech, introduced
subcontractor Tom Ryon, biologist from Ottertail Environmental, Inc. Gary said that the
acreages that Tom had quantified were based on inundation at 5432, 5437, and 5444 feet
above mean sea level (msl) for the no-action, 7,700 AF, and 20,600 AF alternatives
respectively and did not include any additional acres inundated by flood events. He also
stated that the information presented by Tom is not intended to address the effects of the
reservoir model such as the frequency or duration of inundation or the timing
(seasonality) of inundation. These effects will be addressed later in the FR/EIS.
Tom spoke to the group using PowerPoint slides. Two surveys were conducted in
2004 and 2005 for the Federally Listed Threatened Ute ladies’ tresses orchid (Spiranthes
diluvialis) and Colorado Butterfly Plant (Gaura neomexicana ssp. coloradensis), but
none were found at Chatfield. Surveys of birds and of different habitats used by birds,
including migratory birds, were conducted in 2006. Data was mapped in the study area
using GIS, and this data was field verified. In response to a question from Ann Bonnell
regarding data sources, Tom stated that he used the Breeding Bird Atlas; met with Joey
Kellner (amateur birder with extensive field experience at Chatfield, who provided Tetra
Tech with his Chatfield database and checklist); and integrated into the FR/EIS
information from the article on why the heron rookery disappeared. Ann added that Tony
Lukering of the Rocky Mountain Bird Observatory had a computer database of the first
Breeding Bird Atlas. Gary indicated that Tetra Tech has this information and is including
it in Chapter 3 of the FR/EIS. Tom used the survey data to identify sub-classifications
within three habitats – Preble’s meadow jumping mouse (Preble’s) habitat, wetlands, and
migratory bird habitat – that will help evaluate mitigation sites and needs. The
methodology for identifying different types of habitat was coordinated at a May 10, 2006
meeting attended by Gary, Tom, Pete Plage, and Betty. Ann requested that the
PowerPoint slides be emailed to meeting attendees, and the Corps agreed to consider the
request. [The Corps will email the PowerPoint slides to meeting attendees, with the
understanding that the acreage data was preliminary and that the PowerPoint slides were
not to be provided to anyone outside the attendees’ organization.]
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PREBLE’S MEADOW JUMPING MOUSE HABITAT IMPACTS AND MITIGATION
CONSIDERATIONS
Tom quantified the number of affected (inundated) acres of Preble’s habitat that
were high-value riparian habitat (shrubs with a dense understory of vegetation and some
trees, located along a main stream); low-value riparian habitat (treed areas with an
understory and adjacent to upland areas); and upland habitat. The affected acres of
designated critical habitat within each of these three sub-classifications were also
quantified. Preble’s total occupied range at the Chatfield project was 1764 acres; of this,
about 332 acres would be inundated at 5444 feet msl and about 138 acres would be
inundated at 5437 feet msl. The great majority of Preble’s habitat impacted by the
reallocation was high value riparian habitat. However, only about one-fifth of the acres
inundated by either of the action alternatives was designated critical habitat. Tom, Pete,
and Susan Linner explained that was partly due to critical habitat being designated by a
standard “setback” from the South Platte River that may not have included all habitat
suitable for Preble’s along the South Platte River in Chatfield State Park (SP). They said
it was also partly due to the fact that the Final Rule (a handout of which was provided to
attendees) designated no critical habitat in the Plum Creek Drainage on private lands or
on Chatfield SP lands. However, a 1998 Corps survey showed that Preble’s occupies the
Plum Creek area in Chatfield SP. Pete noted that the USFWS considered the Plum Creek
drainage as an important recovery area for Preble’s. To aid the group’s mitigation
efforts, all attendees would be provided with the Proposed Rule [this was emailed June 7,
2007], which did include lands in the Plum Creek Drainage and maps. Pete and Susan
did not feel any additional surveys for Preble’s were needed in the Chatfield SP area.
Susan and Pete agreed that the USFWS was focusing on habitat impacts, not on mice
mortalities resulting from inundation.
As a handout, Pete provided a letter showing guidelines for the ratio of mitigation
land acres to affected acres. He noted that Preble’s habitat is rarely created; mitigation
usually involves restoration or enhancement. The enhancement ratio is usually 2:1 or
3:1, not 1.5:1 (which is more appropriate for restoration). He explained to the group that
the USFWS had no rigid standards regarding mitigation ratios. The mitigation ratios
required would depend on the type and quality of the habitat, the likelihood of successful
habitat development/enhancement, the proximity of the mitigation site(s), and whether
they were in the same basin as the affected area(s). Pete indicated that if any mitigation
efforts were successfully implemented in advance, this would demonstrate likelihood of
success and could result in lower ratios. No additional mitigation requirements would be
imposed for adverse modifications to designated critical habitat than for adverse impacts
on habitat of similar quality that was not designated as critical habitat. The USFWS
wants to be satisfied that impacts of the project on Preble’s are offset. In regard to
success criteria, Pete referred group members to those used by the Corps’ Littleton, CO
Regulatory Office. [The success criteria were provided to attendees by email June 7.]
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MIGRATORY BIRD HABITAT IMPACTS
Activities at the Chatfield Project must comply with the provisions of the
Migratory Bird Treaty Act, which will still protect bald eagles even if they are no longer
Federally Listed as a Threatened species. Tom had six sub-classifications of migratory
bird habitat: mature cottonwood, shoreline, shrub, trees, upland, and non-woody wetland.
Pool elevations of 5444 and 5437 feet msl would inundate over 453 acres and over 200
acres of migratory bird habitat, respectively. Compared to pool elevations of 5437 feet
msl, pool elevations of 5444 feet msl would inundate about 30 times the acres of mature
cottonwoods, about 10 times the acres of uplands, and not more than about twice the
acres of each of the other four sub-classifications. Pete indicated that a low berm along
the South Platte River near the northern end of the gravel ponds could result in avoiding
impacts to many cottonwoods. [It should be noted that bald eagles favor mature
cottonwoods near water for roosting.] The survey of migratory birds showed that shrubs,
trees, and wetlands were relatively equal in regard to average species richness and bird
abundance.
WETLANDS IMPACTS
Tom coordinated with Terry McKee of the Corps’ Littleton, CO Regulatory
Office in identifying and mapping jurisdictional wetlands and determining acres impacted
by the two action alternatives: about 115 and 70 acres for the 20,600 AF and 7,700 AF
alternatives, respectively. Margaret Langworthy noted that some wetlands shown on the
map on the PowerPoint slide may appear isolated but could be connected by
groundwater; whether they are “connected by groundwater” or “adjacent” will be based
on the Rapanos Guidance [to which a Web link was emailed to all attendees June 7,
2007]. Tom quantified impacts on five sub-classifications of wetlands: emergent,
submergent, scrub/shrub, seasonal, and other. By far the largest acreage affected was to
scrub/shrub wetlands, which is also important for Preble’s habitat. Margaret indicated
that because Chatfield Dam was constructed prior to 1977, no regulatory permit was
required for a change in operations that result in altering reservoir surface elevations,
range/frequency of fluctuations, etc. However, any additional modification (such as any
discharge into wetlands, relocating a road onto a wetlands, or implementing an
environmental mitigation activity that disturbs wetlands) would require a permit.
Margaret agreed with Katie Fendel’s suggestion that Terry McKee should be consulted if
any recreational or environmental mitigation activities appear to affect a wetland area. In
addition, the Federal Government has a “no net loss of wetlands” policy, and this means
impacts to non-jurisdictional wetlands (which may be isolated, not satisfy all three
criteria for jurisdictional wetlands, etc.) must still be addressed. The National
Environmental Policy Act (NEPA) also requires disclosure of impacts to all wetlands, not
only those wetlands subject to permitting. Margaret added that mitigation requirements
for Preble’s are much more specific than for wetlands; there is much more flexibility in
mitigating for wetlands impacts. It was agreed that no functional assessment of impacted
wetlands was needed for Regulatory or mitigation purposes.
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The total impacted acres needing to be mitigated for will be less than the sum of
impacted wetlands acres, Preble’s habitat acres, and migratory bird habitat acres. This is
because there is considerable overlap of these habitats, and many acres are in two or three
of these categories. [Tetra Tech will be preparing a map that will show the extent of
overlap of these habitats.]
POTENTIAL MITIGATION OPTIONS ON-PROJECT/ ON-SITE
(* Indicates the area was visited during the afternoon field trip)
*Riparian and Upland Mitigation Areas at Chatfield Arboretum. Larry
Vickerman indicated that Denver Botanic Gardens (DBG) would be interested in having
mitigation for riparian and/or upland areas on the lands they lease from the Corps. DBG
was not interested in having any additional wetlands mitigation on their leased area
because they have four wetland ponds that were created to serve as a CO Department of
Transportation (CDOT) mitigation site to offset highway construction impacts on
wetlands elsewhere in Colorado, but during the last few years CDOT did not provide an
adequate supply of water to the wetlands, which negatively affected vegetation in and
near the wetland ponds. Larry indicated that the understory [grasslands] along Deer
Creek was not in very good condition, but the trees and shrubs were in average condition.
The group agreed that water rights would be needed to provide water to mitigation areas
at the Arboretum because Deer Creek flows vary greatly by season. Larry indicated that
unless water rights issues could be worked out for riparian mitigation, DBG preferred to
provide mitigation only for uplands. He stated that DBG had already identified upland
areas for enhancement for migratory bird habitat. Tetra Tech will obtain/use these plans
for more detailed information regarding potential mitigation activities.
Weed Control. Susan advised the group that weed control was an enhancement
measure that should be considered in mitigation plans. She also indicated that on-site
mitigation, especially if “in-kind” (with similar habitat attributes) would have lower
required ratios of mitigation acres to impacted acres than if mitigation were off-site,
especially if the off-site mitigation was “not-in-kind”. Pete indicated that USFWS is not
interested in “predator control” (e.g., feral cats) as means of Preble’s mitigation.
Lakeside Riparian Areas. Margaret suggested that trees for riparian habitat could
be planted above 5444 feet msl in advance of the storage reallocation and watered to
ensure survival, so they would be able to function as migratory bird habitat when storage
reallocation inundated trees in the existing lakeside riparian habitat. Another comment
was made that since water levels would only reach 5444 feet msl every 3 to 4 years,
watering facilities would be needed even after reallocation is implemented.
*Berm along the South Platte River to Reduce Impacts on Cottonwoods. Pete
suggested that a low berm 1 to 2 feet high be constructed along one or both banks of the
South Platte in the vicinity of the north end of the gravel pits, if there are relatively flat
areas of high quality habitat at the perimeter of the proposed 5444 ft msl pool. He
thought the berm would reduce flooding of the mature cottonwoods in that area to a low
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enough frequency that the trees would survive and continue to provide habitat for wildlife
and migratory birds, including bald eagles. [Fred added that any berm construction
would need to meet the criteria provided in the Corps’ Northwestern Division’s Land
Development Guidance at Corps Reservoir Projects, NWDR1110-2-5; the Corps will
evaluate the feasibility of implementing this option for avoidance/reduction of impacts to
mature cottonwood habitat.]
*Gravel Pond Wetlands along Last Chance Ditch. Kent Wiley proposed that
gravel ponds be excavated along the Last Chance Ditch, near the southwest boundary of
the Chatfield project. Last Chance Ditch is an active irrigation ditch, the diversion point
of which had been changed. Rick McLoud indicated the headgate was located far
upstream from Chatfield SP. Fred Rios indicated that the point of diversion was changed
to below Chatfield and would check whether the Corps acquired the ditch on Corps
property as part of the relocation contract. If so, it could be used to divert water from the
South Platte into the gravel ponds. Riparian wetlands could be developed around the
edge of the gravel ponds. (An alternative use for the gravel ponds is for additional water
storage if the 7,700 AF alternative is implemented rather than the 20,600 AF alternative;
Fred indicated that the addition of gravel pit storage to the 7,700 AF alternative would be
an additional alternative.) Kent said he would prepare a more detailed writeup of his
proposal and provide it to Betty Peake.
*Restoration of Wetlands Previously Constructed by Lockheed Martin and
Denver Water Department. Kent indicated that approximately 13 acres of wetlands was
constructed west of the South Platte River near the southern boundary of Chatfield SP.
The wetlands contain many cells of varying sizes that filtered effluent from Lockheed
Martin (formerly Martin Marietta). The effluent reached the wetlands by flowing
through a ditch that is located close to a viewing platform and interpretive area. Usage
was recently discontinued by order of the Colorado Department of Health when water
quality testing showed one of the components of the effluent exceeded State of Colorado
standards. The effluent now flows through a pipeline that was installed across Chatfield
SP near the wetlands and is discharged into the South Platte River. It was proposed that
the wetlands be restored and the water providers release water (using their water rights)
into the old inflow ditch (Last Chance Ditch).
Enhanced Wetlands in Marcy Gulch downstream from Chatfield Dam. Kent and
Brad Buckner suggested that wetlands and a meander could be restored along Marcy
Gulch, which was presently downcutting and had water quality problems. Brad provided
Betty Peake with a master’s thesis by Jill D. Henderson that proposed a conceptual
design for an environmental “make-over” of the 47-acre tract just east of the Cottonwood
Grove Picnic Area. [Betty summarized the proposed design as follows. It would serve
multiple objectives and have both open water and vegetated areas to offer habitat
diversity for a variety of fish and wildlife species. It would include three to eight 6-acre
pond-wetland cells, which would accommodate daily discharge volumes of 2.7 to 8 mgd
from the Highland Ranch wastewater treatment facility. Each pond would contain
alternating shallow and deeper water areas and submergent vegetation (Elodea species
and Ceratophyllum demersum). From 25 to 50 percent of each pond would consist of a
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littoral zone, with water only 6 to 18 inches deep and a variety of emergent vegetation.
To accommodate larger stormwater flows, the proposal included: widening the existing
stream channel, without removing trees; stabilizing stream banks by decreasing the slope,
planting vegetation, and using bio-stabilization (e.g. logs) where needed; and facilitating
limited seasonal flooding for cottonwood germination. Small trees should be protected
from beavers, and dikes/berms should be protected from rodents. Design considerations
and criteria should conform to Urban Drainage and Flood Control District standards.
Based on material in the thesis, Betty noted that a side channel could also be constructed;
irregular pond perimeters, coves, mudflats, sandbars, and vegetated islands would further
increase the diversity of habitats and wildlife species; and duckweed and mosquitofish
could reduce mosquito larvae.] [Rick McLoud also has a copy of the thesis and offered
to provide copies of relevant portions of the thesis or the entire thesis, as he deems
appropriate or as requested, to members of the group and to the Water Users’ mitigation
subcommittee.]
*Wildlife Corridor along Highline Canal. Tom indicated that Douglas County
had proposed planting trees as a wildlife corridor along the Highline Canal between Plum
Creek and the South Platte River during the agency scoping meeting in February 2005.
This proposal was reiterated to Tom recently by Andy Hough of Douglas County, who
stated that Shea Homes and Lockheed Martin were interested in implementation of this
proposal. They thought that the corridor could be used by Preble’s. Fred disagreed
because the Highline Canal sits on a bench, and the creek is much lower in elevation.
Pete concurred that the corridor was much more practical for wildlife other than Preble’s,
and in 1998 Preble’s meadow jumping mice were caught adjacent to the Highline Canal
right-of-way (near Plum Creek and the South Platte River) but none were caught adjacent
to the canal alignment between the two streams. However, Pete stated that connectivity
between Plum Creek and the South Platte was also important.
Enhanced Wetlands along Plum Creek. Joel Knofczynski presented a proposal
for wetlands behind a series of weirs or check dams in Plum Creek that was mentioned
briefly in the Planning Aid Letter and discussed at the May 10, 2006 working group
meeting with USFWS. A series of check dams or weirs, each of which would extend
across Plum Creek, would begin at 5444 feet msl and continue upstream within Chatfield
SP. The banks behind each weir would be graded to make the bank relatively flat farther
away from the stream. Sediment would deposit behind the weirs and on the graded
banks, causing the bed to rise and shallow wetlands to form and spread laterally, beyond
the pre-reallocation wetland boundary. Sediment, and metals attached to the sediment
particles, would be kept out of the lake to some degree. The weirs or check dams would
need to be notched to allow fish passage. Sediment in Plum Creek is a big problem
because development upstream has resulted in increased stormwater discharges, which
have degraded the creek bed and eroded banks upstream. Joel indicated that pumps
would still be needed to maintain the wetlands because the soils tend to be very well
drained. In addition, the wetlands would likely need to be lined.
Reduction in Lake Level Fluctuations to Increase Boater Safety. Dave Giger was
concerned that when water levels are low for a few years, cottonwoods would grow along
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the exposed non-vegetated area (that was previously lakebed) for a few years, resulting in
dead trees below the water level when the lake elevation rises again. This would
preclude boating or swimming in the area for reasons of public safety. Rick responded
that the water providers could modify their operating plan by maintaining higher lake
elevations through the summer, provided inflows into the lake had been adequate, i.e.
during non-drought years. Users can accommodate being constrained on how and when
they take water out of Chatfield. However, they don’t want to be constrained on when
they put water in Chatfield, as they need to take advantage of water inflow opportunities
as they occur in order to fill as much of the reallocated joint flood control-conservation
pool as possible each year. Colorado State Parks staff indicated that the lake fluctuations
expected at Chatfield were small compared to the 60 feet experienced at Pueblo
Reservoir and 90 feet at Trinidad Reservoir. Ken Brink recommended that the Chatfield
Basin Conservation Network (CBCN) be included in the next meeting, as they were very
involved in the preservation of wildlife corridors in the basin. [Corps-Omaha will
coordinate with CBCN regarding the organization’s interest in becoming a special
technical advisor for the Chatfield Storage Reallocation Feasibility Study; this status will
ensure confidentiality of information presented and/or discussed at the meetings.]
POTENTIAL MITIGATION OPTIONS OFF-PROJECT/ OFF-SITE
Sites along East Plum Creek and West Plum Creek. Tom told the group that
Andy Hough of Douglas County had suggested to him four potential mitigation sites in
the East and West Plum Creek drainages, just upstream of Chatfield SP.
Enhancing of Chatfield Watershed Authority’s Wetlands. Katie suggested that
the wetlands Chatfield Watershed Authority constructed as a “trade” or “trade-off” for
high phosphorus discharges could possibly be enhanced, and the enhancement could be
part of the proposed mitigation plan. Tom will contact Russ Clayshulte for more
information on this suggestion.
Enhancing Connectivity with Columbine Wildlife Area. Members of the group
suggested investigating Bell Mountain Ranch, an old gravel mine area, and the Iron
Horse area upstream from Columbine Wildlife Area to enhance the connectivity with
Columbine Wildlife Area.
*Hildebrand Open Space Area in Jefferson County. Tom presented a slide that
showed the Jefferson County (JeffCo) Open Space boundaries as a red line. He pointed
out the location of JeffCo’s Hildebrand Open Space area that was adjacent to the
Chatfield Arboretum area DBG leases from the Corps. Tom thought the Hildebrand
Open Space area could be used for mitigating adverse effects to riparian and migratory
bird habitat. Ann Bonnell cautioned that JeffCo Open Space purchased the Hildebrand
Ranch Open Space area with GOCO funds, and these areas are restricted in regard to
development of trails, etc. Dave Giger advised the group that JeffCo needed to be
consulted before identifying any areas as potential mitigation sites. [Tom has had initial
discussion with JeffCo regarding mitigation sites.]
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River Canyon Reach of the South Platte River. Fred indicated that the Corps had
a flowage easement in a low-lying area east of the bridge that might be a good potential
mitigation site. Ann cautioned the group that Andy Hough said that 100 acres along the
river was not supposed to be built on.
Section 36 School Lands near Waterton Canyon. Tom stated that Andy Hough
told him that school-owned property in Section 36, which was located near Waterton
Canyon and was adjacent to designated critical habitat for Preble’s, was available for
mitigation activities.
Upstream Water Rights Releases to Sustain Wetlands near South Platte River.
Katie indicated that Brighton has a few senior water rights for South Park. Brighton
plans to store those releases in Chatfield. She suggested that instead of using pumps to
provide water to a small mitigation wetlands along the South Platte, Brighton’s water
could be diverted through the wetlands and then continue flowing downstream to
Chatfield, doing double duty. Fred reminded the group that if water releases were used to
sustain wetlands, evaporation would have to be accounted for. Ken Brink indicated that
whenever the opportunity was available, he favored bringing water down the river over
pumping water. Katie and Ken agreed that coffer dams could be involved in using
upstream-water to sustain wetlands. Ken told the group that Brooke Fox of the Chatfield
Basin Conservation Network (CBCN) indicated to him that the CBCN, which
encompasses open space, environmental, and recreation points of view, has a lot of GIS
maps that the group could use in mitigation planning. Group members thought that Ray
Sperger, who used to work for South Suburban Parks and Recreation District and now
works for CBCN, would be a good point of contact regarding potential mitigation sites.
[Tom Ryon will obtain this information from CBCN staff.]
Sites along the South Platte River within Pike National Forest. Pete indicated that
the South Platte unit of designated critical habitat for Preble’s includes Pike National
Forest lands. Sites within Pike National Forest could be included in the mitigation plan,
but this option is not preferred.
Mitigation Bank Wetlands. Katie indicated that a mitigation bank was located
near Brighton but was primarily used by Brighton. Susan indicated there was a
mitigation bank in the Plum Creek basin, but this was for use by CDOT. Margaret
thought the South Park mitigation bank (near Fairplay) was too far upstream in the South
Platte basin to be an effective mitigation option. However, she indicated that all
mitigation banks in the area were listed on the Corps’ Regulatory Web site [a link to
which was provided by email June 7].
Other Potential Mitigation Sites. Tom indicated that, in addition to suggestions
from Douglas and Jefferson County officials, Urban Drainage and Flood Control District
lands, Denver Mountain Parks, South Platte Park, and mining sites may be available for
mitigation activities. These opportunities would need to be investigated further.
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Margaret suggested that Rick McLoud could provide expertise on acquiring gravel ponds
for riparian and/or wetlands mitigation.
The site of the Penley Reservoir, the Upstream Water Users’ no-action
alternative, was also viewed from the road right-of-way.
ACTION ITEMS COMPLETED
1. Proposed Rule for Designating Critical Habitat for Preble’s emailed to attendees
6-7-07.
2. Corps’ CO Regulatory Office’s success criteria, Web link to Rapanos Guidance,
and Web link to Corps Regulatory Web site emailed to attendees 6-7-07.
3. Betty Peake provided details of the Marcy Gulch mitigation option proposed in
Jill Henderson’s master’s thesis in the Meeting Summary.
4. In response to Ann Bonnell’s request, Corps-Omaha will email to meeting
attendees the PowerPoint slides that were presented at the meeting, with the
understanding that the acreages cited were preliminary and that the slides could
not be provided to anyone outside the attendee’s organization.
ACTION ITEMS NOT YET COMPLETED
1. Kent Wiley will email details of his proposal to excavate gravel
pits/ponds/wetlands along Last Chance Ditch to Betty [and also to Fred Rios and
Eric Laux] for further review as a mitigation option.
2. Fred Rios will check whether the Corps acquired the portion of Last Chance Ditch
on Corps property as part of the relocation contract.
3. Tom Ryon will contact Russ Clayshulte regarding potential for enhancement of
the Chatfield Watershed Authority’s existing “trade-off” wetlands site.
4. Tom Ryon will coordinate further with Douglas County, Jefferson County Open
Space, and other appropriate entities to obtain more details on the mitigation
options that were proposed in general terms at the meeting.
5. Tom Ryon will contact Ray Sperger of the Chatfield Basin Conservation Network
to identify and obtain information regarding any additional mitigation
options/sites.
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6. Tom Ryon will contact Brooke Fox of the Chatfield Basin Conservation Network
to identify any GIS mapping that Tetra Tech does not already have and that may
be useful for identifying potential mitigation options, sites, and plans/designs.
7. Tom Ryon will obtain/use Denver Botanic Gardens’ plans for upland habitat
restoration/ enhancement to provide more details regarding potential mitigation
activities.
8. Joel Knofczynski will further investigate and assess on-site mitigation options in
regard to soils, hydrology, and pumping requirements (if needed for
sustainability).
9. Corps-Omaha staff will assess whether berm construction along the South Platte
near the gravel ponds meets Corps’ Northwestern Division development criteria.
10. Corps/Tetra Tech will prepare a table of mitigation options with location map(s).
11. Rick McLoud will provide relevant material from Jill Henderson’s thesis on an
environmental make-over of Marcy Gulch to members of the group and to the
Water Users’ mitigation subcommittee.
12. Rick McLoud will provide information on procedures and timeframe for
acquiring gravel ponds for riparian and/or wetlands mitigation.
13. Tom Ryon will prepare a map showing overlap of wetlands, Preble’s, and
migratory bird habitats.
14. Corps-Omaha will coordinate with the Chatfield Basin Conservation Network
(CBCN) regarding areas of expertise and interest in participating in identifying
potential mitigation sites, attending environmental mitigation subcommittee
meetings, and providing input to the environmental mitigation conceptual plan. If
the interest is mutual, the Corps will invite the CBCN to be a special technical
advisor to ensure confidentiality of information presented by all meeting
attendees.
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