Rocky Flats

National Wildlife Refuge

Resource Inventory

U.S. Fish & Wildlife Service
Rocky Flats 

National Wildlife Refuge

Resource Inventory

April 2003

Prepared by: 

ERO Resources Corp. 

1842 Clarkson St. 

Denver, Colorado 80218 

(303) 830-1188 

Contents 

Geology and Soils ............................................................................................................................1

Surficial and Bedrock Geology..................................................................................................1

Geologic Hazards.......................................................................................................................1

Mineral Resources.....................................................................................................................3

Soils...........................................................................................................................................3

Soil Contamination ....................................................................................................................5

Water Resources...............................................................................................................................5

Surface Water ............................................................................................................................5

Ground Water ............................................................................................................................9

Future Hydrological Conditions ................................................................................................9

Vegetation Communities................................................................................................................11

Grasslands................................................................................................................................11

Shrublands ...............................................................................................................................15

Woodlands...............................................................................................................................16

Wetlands..................................................................................................................................16

Noxious Weeds...............................................................................................................................17

DOE’s Current Weed Management.........................................................................................19

Fire History and Management........................................................................................................20

Prescribed Burns......................................................................................................................20

Wildlife...........................................................................................................................................21

Mammals .................................................................................................................................21

Birds.........................................................................................................................................22

Reptiles and Amphibians.........................................................................................................24

Aquatic Species .......................................................................................................................24

Wildlife Species of Special Concern .......................................................................................25

Federal Threatened, Endangered and Candidate Species...............................................................26

Preble’s Meadow Jumping Mouse...........................................................................................27

Bald Eagle................................................................................................................................27

Black-tailed Prairie Dog ..........................................................................................................27

Plant Species............................................................................................................................29

Cultural and Historical Resources..................................................................................................29

Prehistoric Resources...............................................................................................................30

Historic Resources...................................................................................................................30

Infrastructure, Easements, and Utilities..........................................................................................32

Utilities ....................................................................................................................................32

Mineral Rights.........................................................................................................................34

Water Rights............................................................................................................................35

Surrounding Land Use....................................................................................................................35

Municipalities..........................................................................................................................35

Woman Creek Reservoir Authority .........................................................................................36

Open Space ..............................................................................................................................36

Other Nearby Land Uses..........................................................................................................36

Open Space, Recreation and Trails ................................................................................................37

City of Boulder Open Space and Mountain Parks...................................................................37

RESOURCE INVENTORY i
Boulder County Open Space....................................................................................................39

Jefferson County Open Space..................................................................................................39

Eldorado Canyon State Park....................................................................................................39

City of Arvada Open Space .....................................................................................................39

City of Westminster Open Space.............................................................................................40

City and County of Broomfield Open Space ...........................................................................40

Town of Superior Open Space.................................................................................................40

Proposed Trails and Open Space Facilities..............................................................................40

Air Quality......................................................................................................................................41

Socioeconomics..............................................................................................................................41

Population and Demographics.................................................................................................41

Employment.............................................................................................................................42

Income .....................................................................................................................................42

References......................................................................................................................................42

Tables 

Table 1. Vegetation Communities at Rocky Flats.........................................................................11

Table 2. Major Noxious Weeds at Rocky Flats.............................................................................19

Table 3. Wildlife Species of Special Concern at Rocky Flats.......................................................26

Figures

Figure 1. Surficial Geology. ............................................................................................................2

Figure 2. Soils..................................................................................................................................4

Figure 3. Water Resources. .............................................................................................................6

Figure 4. Vegetation. .....................................................................................................................12

Figure 5. Noxious Weeds. .............................................................................................................18

Figure 6. Wildlife Resources.........................................................................................................23

Figure 7. Potential Prairie Dog Habitat .........................................................................................28

Figure 8. Cultural Resources. ........................................................................................................31

Figure 9. Infrastructure, Easements and Utilities. .........................................................................33

Figure 10. Regional Open Space and Trails..................................................................................38

RESOURCE INVENTORY ii
Geology and Soils 

The 6,240-acre Rocky Flats site is located at the interface of the Great Plains and Rocky Mountains, about 2 miles east of the foothill escarpment in Jefferson County, Colorado. Site elevation 

ranges from 5,500 feet in the southeastern corner to 6,200 feet near the current west entrance 

gate. The western half of site is characterized by the relatively flat Rocky Flats pediment, which 

gives way to several finger-like drainages that slope down to the rolling plains in the eastern 

portion of the site.

Surficial and Bedrock Geology 

Geologic units at the Rocky Flats site range from unconsolidated surficial deposits to various 

bedrock layers (Figure 1). Surficial deposits in the western portions of the site are characterized 

by the Rocky Flats Alluvium, clayey and sandy gravels between 0 and 100 feet thick. The 

steeper slopes below the Rocky Flats Alluvium in the central portion of the site generally consist 

of landslide deposits. Surficial deposits in the eastern portion of the site consist of colluvium 3 to 

15 feet thick and terrace alluvium 10 to 20 feet thick (Shroba and Carrara 1996). 

The Rocky Flats Alluvium is underlain by the Arapahoe Formation, composed of sandstones, 

siltstones, and claystones that range from 0 to 50 feet thick. In several locations, springs emerge 

at the contact of the Rocky Flats Alluvium and the Arapahoe Formation. These springs support 

the tall upland shrubland community described in the Vegetation Communities section. Beneath 

the Arapahoe Formation lies the Laramie Formation, composed of 600 to 800 feet of silty to 

clayey sandstones, clayey siltstones, and claystones. The Laramie Formation is underlain by the 

Fox Hills Sandstone and Pierre Shale.

Geologic Hazards 

Landslides and landslide deposits are common along the steep hillsides and incised drainages at 

the base of the Rocky Flats Alluvium escarpment. These deposits occur in areas where bedrock 

layers such as the Arapahoe Formation are capped by unconsolidated gravel formations such as 

the Rocky Flats Alluvium. While most of the landslide deposits are of Pleistocene origin, some, 

especially those in the Rock Creek drainage, are likely more recent. Many landslide areas have

high swell potential, and are subject to sheet wash and soil creep (Shroba and Carrara 1996). 

RESOURCE INVENTORY 1
Figure 1. Surficial Geology. 

RESOURCE INVENTORY 2
Seven geologic fault lines have been identified at Rocky Flats, including a northeast-trending 

reverse fault that extends across the western part of the Industrial Area. These faults are not 

believed to be a concern in regards to current or future human activities or facilities at the site 

(DOE 1997).

Mineral Resources 

The Rocky Flats Alluvium is believed to be the only mineral resource feasible for development at 

the NWR. Historically, uranium, coal, oil and natural gas have been extracted near the Rocky 

Flats site. None of these mineral resources, however, appear to be feasible for development 

(DOE 1997). Mining rights and permits at the site are described in the Infrastructure, Easements, 

and Utilities section. 

Soils 

The soils at the site formed from alluvium (stream deposited), colluvium (gravity deposited), or 

residuum (exposed bedrock material). Soils in the western half of the site formed from alluvium, 

while those in the eastern half of the site formed from colluvium and residuum. Rocky Flats soils 

are shown in Figure 2. 

Soils in the western half of the site are primarily the Flatirons and Nederland soils that formed in 

the Rocky Flats Alluvium. Flatirons soils consist of very cobbly to very stony loamy surfaces 

and clayey subsoils. These soils are deep and well drained. Flatirons soils are located on western 

pediment and ridgetops, as well as the upper portions of hillsides. Nederland soils have very

cobbly loamy surfaces and subsoils. They are deep and well drained. Nederland soils are located 

on steeper hillsides and valley slopes in the western portion of Rocky Flats. 

Soils in the eastern portion of the site consist primarily of Denver, Kutch, Midway, Valmont, 

Haverson, and Nunn soils. The Denver-Kutch-Midway complex consists of soils with loamy

surfaces and clayey subsoils. The Denver soils are deep and well drained, the Kutch soils are 

moderately deep and well drained, while Midway soils are shallow and well drained. The 

Denver-Kutch-Midway complex is the dominant soil map unit in eastern portion of Rocky Flats, 

though it also occurs in western half along hillsides. Denver and Kutch soils are found on side 

slopes, and the Midway soils occur on steeper slopes. Valmont soils consist of deep, well-drained 

soils with loamy surfaces and loamy to clayey subsoils. This soil type is found in northeast 

corner of Rocky Flats on the eastward extension of the Rock Creek/Walnut Creek drainage 

divide. Haverson soils are loamy soils located in floodplains or low terraces. Nunn soils consist 

of deep, well-drained soils on lower slopes adjacent to drainage bottoms. They have loamy

surfaces and loamy to clayey subsoils. 

RESOURCE INVENTORY 3
Figure 2. Soils. 

RESOURCE INVENTORY 4
Soil Contamination 

Elevated concentrations of plutonium and americium are currently found in the eastern portion of 

the site. Concentrations are highest on the eastern end of the Industrial Area, adjacent to the 903 

Pad (DOE 1997). The 903 Pad is an area where industrial oil mixed with plutonium was stored in 

steel drums from 1958 to 1968. This mixture leaked onto the soils in the storage area, and these 

contaminated soils were subsequently blown by the wind and deposited to the east and southeast. 

In 1968, the storage area was capped with asphalt to prevent further release of contaminated soils. 

The contaminated area to the east of the 903 Pad is known as the 903 Lip Area. DOE plans to 

remediate the contaminated soils and retain jurisdiction over the area. 

Water Resources 

Surface Water 

Three drainages originate on or near Rocky Flats: Rock Creek, Walnut Creek, and Woman 

Creek. Stream levels fluctuate depending on the season and amount of precipitation. Most 

streamflow is controlled by ground water discharge; streamflow is higher when ground water 

levels are higher, such as in the spring. Surface sheet flow is only a significant contributor to 

stream flows during high precipitation events (Kaiser-Hill 2002b). Water resources on Rocky 

Flats are shown on Figure 3. 

Under current plans, no water will be imported to the Rocky Flats site once it is converted to a 

National Wildlife Refuge. Presently, the site purchases about 340 acre-feet/year of water from

Denver Water. This water is stored in a raw water reservoir west of the Industrial Area, and then 

used for domestic purposes and in cooling towers. After use, domestic water is treated at the 

Wastewater Treatment Plant (WWTP) on the eastern edge of the Industrial Area, before it is 

released into pond B-3. From pond B-5, water is periodically released to Walnut Creek (KaiserHill 2002b). 

Rock Creek 

The Rock Creek basin drains the northwest portion of the site. This drainage is characterized by

relatively flat headwater areas to the west, and steep gullies and channels to the east where it cuts 

below the Rocky Flats Alluvium into bedrock formations. Rock Creek is hydrologically isolated 

from the rest of the site, and receives no water from the Industrial Area. Surface water generally 

originates from precipitation and shallow ground water discharge. Rock Creek continues off-site 

to the northeast, where it joins Coal Creek in the Boulder Creek basin (DOE 1997). 

RESOURCE INVENTORY 5
Figure 3. Water Resources. 

RESOURCE INVENTORY 6
Walnut Creek 

Walnut Creek consists of three tributaries that drain the central portion of the site, including most 

of the Industrial Area. The northernmost branch begins at the outfall of the East Landfill Pond. 

The central branch, North Walnut Creek, begins at the northern edge of the Industrial Area and

flows through the “A” series ponds. South Walnut Creek begins within the Industrial Area and 

collects discharge from the Rocky Flats Wastewater Treatment Plant before flowing through the 

“B” series ponds. The three branches converge near the eastern Rocky Flats boundary before 

flowing off-site to the east. 

Before 1992, Walnut Creek flowed into Great Western Reservoir and on to Big Dry Creek. The 

Broomfield Diversion Canal was constructed in 1992 to divert Walnut Creek water away from the 

reservoir. Walnut Creek is typically dry during most of the year. 

During precipitation events, Walnut Creek flows typically do not increase due to high soil

infiltration rates. Stream flows are dominated by pond releases. Typically, about one-third of the 

water released from the ponds goes into ground water. Terminal Pond A-4 releases about 51 

acre-feet per event into North Walnut Creek and is discharged two to four times per year. Pond

B-5 releases about 44 acre-feet per event into South Walnut Creek and is discharged six to eight 

times per year (Kaiser-Hill 2002b). 

Woman Creek 

The Woman Creek basin drains the southern portion of the Rocky Flats site. The Woman Creek 

drainage consists of two major branches that both begin off of the Rocky Flats site to the 

southwest. The main stem of Woman Creek flows across the site, passing to the south of the 

Industrial Area and flowing through the C-1 pond. The Mower Ditch diverts most of the flow

into Mower Reservoir, east of Rocky Flats. 

Similar to the Rock Creek drainage, the upper reaches of Woman Creek are characterized by 

shallow or indistinct channels. Alluvial soils along Woman Creek have high infiltration rates. 

The middle reaches of Woman Creek are more incised and have steeper gradients and side slopes. 

The eastern reaches of Woman Creek occupy a broad, gently sloping valley.

Typically, Woman Creek has no streamflow in late spring and summer. All surface flows are lost 

to ground water in the warmer months. In the winter, most of the baseflow is from Antelope 

Springs. Woman Creek is largely unaffected by pond releases (pond C-2 is discharged about 

once a year, with a release of 38 acre-feet). The average daily flow rate is 0.47 cfs. 

RESOURCE INVENTORY 7
Big Dry Creek 

A small portion of Rocky Flats near its southern boundary lies within the Big Dry Creek 

drainage, though the creek itself does not flow onto the site. Big Dry Creek flows into Standley

Lake about 1 mile east of Indiana Street. 

Ditches 

Besides the three principal drainages, several ditches cross the NWR. The South Interceptor 

Ditch currently collects runoff from the south of the Industrial Area, which channels surface 

runoff into the C-2 pond. The Smart Ditch originates at Rocky Flats Lake to the southwest of the 

site, enters Rocky Flats and flows through the South Woman Creek drainage for almost 2 miles 

before splitting off toward Standley Lake to the southeast. The Mower Ditch diverts most of 

Woman Creek toward Mower Reservoir to the east. The Upper Church Ditch enters Rocky Flats 

from the west, and traverses the Rock Creek/Walnut Creek drainage divide until it exits the site in 

the northeast corner. The McKay Ditch runs from the west side of the Industrial Area into the 

Walnut Creek drainage. The Kinnear Ditch diverts water from Coal Creek west of Rocky Flats 

and conveys it to the Woman Creek channel (Advanced Sciences 1991). 

Pond water retention creates local wetland areas and creates artificial, intermittent flow 

downstream. The ponds were not lined when constructed, but do not appear to leak water to 

ground water due to thick layers of fine sediments that have accumulated in them (Kaiser-Hill 

2002b). 

Off-Site Surface Water 

Standley Lake is a large water supply reservoir that serves nearby communities. It is located 

about 1 mile southeast of Rocky Flats on the main stem of Big Dry Creek. Upstream of Standley 

Lake just east of the Rocky Flats site, the Woman Creek Reservoir was constructed to intercept 

any Woman Creek flows that are not diverted through the Mower Ditch. This reservoir is 

intended to protect water quality in Standley Lake. The Mower Reservoir is located north of 

Woman Creek Reservoir on the east side of Indiana Street, and receives Woman Creek water 

through the Mower Ditch. 

Immediately east of the site lies Great Western Reservoir, which is owned by the City and County 

of Broomfield and is used for irrigation. Rocky Flats Lake lies to the south and west of the site 

on land owned by the state. Rocky Flats Lake provides water for the Smart Ditch, which runs 

across the southern end of the site towards the D-2 pond, and eventually, Standley Lake. 

RESOURCE INVENTORY 8
Ground Water 

Hydrogeology at the Rocky Flats site is characterized by three distinct units, the upper alluvial

aquifer, lower aquitard, and the Laramie-Fox Hills aquifer. An aquifer is a geologic formation 

that has sufficient permeability to store and/or convey water. An aquitard is a confining layer 

with low permeability that can store large quantities of water but does not allow water to readily 

pass through it. 

The upper alluvial aquifer is comprised of the unconsolidated materials that can be as much as 

100 feet thick in the western portions of the site. The upper aquifer is generally recharged from

precipitation or surface water bodies. Ground water in the unconsolidated alluvial aquifer is 

generally close to the land surface, with an average depth of 11 feet below ground surface. 

Several springs have emerged in areas where the contact of the upper aquifer and the lower 

aquitard is exposed at the surface. While most of these springs occur within the Rock Creek 

drainage, Antelope Springs in the Woman Creek drainage has the largest discharge at Rocky

Flats. Antelope Springs discharges continuously over several acres. 

The lower aquitard is comprised of the deeper claystone and siltstone of the Laramie and 

Arapahoe Formations. These formations combined are up to 800 feet thick below Rocky Flats. 

Recharge of the lower aquitard occurs from downward flow through the upper aquifer, or directly

through precipitation in areas where the bedrock is exposed. Beneath the aquitard lies the 

regional Laramie-Fox Hills aquifer. It is composed of the lower sandstone unit of the Laramie 

Formation and the Fox Hills Sandstone, and is confined by the overlying aquitard. Ground water 

levels in the bedrock aquifers are generally greater than 100 feet (DOE 1997). 

Several portions of the upper alluvial aquifer east and northeast of the Industrial Area are known 

or suspected of being contaminated with radionuclides, volatile organic compounds, and metals. 

The aquitard is less contaminated than the upper alluvial aquifer. No contaminant plumes have 

been identified in the aquitard. The Laramie-Fox Hills aquifer beneath the site is unlikely to be 

contaminated (DOE 1997).

Future Hydrological Conditions

During site closure, the buildings, pavement and some of the subsurface utilities (to a depth of 3 

feet) will be removed from the Industrial Area and the area will be re-graded. Subsurface utilities 

below 3 feet deep will be assessed individually and may be left in place. Landfill areas will be 

covered and also will be re-graded. These changes will affect the surface and ground water 

hydrology of the site. The following changes that would alter the hydrology of the Rocky Flats

site are expected to occur (Kaiser-Hill 2002b): 

RESOURCE INVENTORY 9
• No more water will be imported to the site. 

• Two channels in the Industrial Area will route water to the A- and B-series ponds. 

• Treatment Plant discharge to pond B-3 will be discontinued. 

• The upper reach of the South Interceptor Ditch will be removed. 

• The Landfill Pond will be reduced in size. 

• Subsurface drains in the Industrial Area will be removed down to 3 feet. 

• Subsurface utilities will be removed and the area will be backfilled with Rocky Flats 

Alluvium, changing the hydraulic conductivity of the subsurface in the Industrial 

Area. 

• Pavement and buildings will be removed in the Industrial Area (some basement slabs 

and walls will be left in place). 

• The Industrial Area and landfill areas will be re-graded to match adjacent topography

and the sites will be vegetated. 

• Landfill areas will be covered and a slurry wall placed along the upgradient side of 

the Original Landfill. 

These changes are expected to affect streamflow in Walnut and Woman creeks. Flow in Rock 

Creek will not be affected.

Walnut Creek 

Changes will occur to Walnut Creek flows due to the elimination of wastewater treatment plant 

discharge to the creek, the removal of impervious areas in the Industrial Area, and the elimination 

of storm water drain discharges in the Industrial Area. Terminal pond (A-4 and B-5) discharges 

would decrease, and Walnut Creek flows will be dominated by pond discharge operations and 

any pond routing or structural modifications. 

Ground water levels along the eastern portion of Walnut Creek will decrease due to reduced pond 

discharges. This would result in reduced baseflow within the creek. Rapid runoff from the 

Industrial Area would be eliminated due to removal of roofs and pavement. South Walnut Creek 

east of the Industrial Area is estimated to lose 90 percent of its annual flow. North Walnut Creek 

east of the Industrial Area is estimated to lose 65 percent of its annual flow. Only one release will 

occur annually from Terminal Pond A-4. The discharge of water off-site from Walnut Creek will 

decrease by 80 percent in wet years and 95 percent in dry years. Riparian and wetland areas 

located along eastern Walnut Creek and around the ponds would have a reduced water supply due 

to reductions in ground water levels, pond levels, frequency and volume of channel flow. 

Woman Creek 

Changes in the flow of Woman Creek would be insignificant, except for the area south of the 

Present Landfill where flows may decrease due to the possible use of covers and slurry walls at 

the landfill site. Drainage to the South Interceptor Ditch and baseflow within the ditch would 

RESOURCE INVENTORY 10
decrease because storm water flows from the Industrial Area will be significantly reduced. 

Changes in ditch flows, however, are not likely to affect Woman Creek flows because water from

the ditch is detained in pond C-2 and the ditch supplies less than 10 percent of the flow of 

Woman Creek at the east boundary. 

Vegetation Communities 

A diverse mosaic of vegetation communities is found at the site. Two of these vegetation 

communities, the xeric tallgrass grassland and the tall upland shrubland, are considered to be rare 

in the region. Other significant vegetation communities include the riparian woodland, riparian 

shrubland, wetlands, mesic mixed grassland, xeric needle and thread grassland, reclaimed mixed 

grassland, and ponderosa pine woodland (Figure 4). 

Table 1. Vegetation Communities at Rocky Flats. 

Vegetation Community Area (acres) Vegetation Community Area (acres) 

Grasslands Woodlands 

Xeric Tallgrass Grassland 1,568 Riparian Woodland 28

Mesic Mixed Grassland 2,199 Ponderosa Pine Woodland 9 

Xeric Needle and Thread Grassland 187 Wetlands 

Reclaimed Mixed Grassland 640 Tall Marsh Wetland 31 

Short Grassland 10 Short Marsh Wetland 121 

Shrublands Wet Meadow 254 

Tall Upland Shrubland 34 Open Water/Mudflats 51 

Riparian Shrubland 41 Other 

Other Shrubland 70 Disturbed and Developed Areas 997 

Total 6,240 

Grasslands

Xeric Tallgrass Grassland 

This rare plant community is found on the rocky plains in the western portions of the site, extending eastward along several finger-like ridgelines. The xeric tallgrass grassland community covers 

1,568 acres of the site. This plant community contains several different plant associations that 

include combinations of big bluestem, little bluestem, mountain muhly, sun sedge, Fendler’s 

sandwort and Porter’s aster. Other tallgrass prairie species include Indian-grass, prairie dropseed, 

switchgrass and needle-and-thread grass. It is found primarily in Flatirons and Nederland soils. 

This community is believed to be a relict once connected to the tallgrass prairie hundreds of miles 

to the east (Nelson 2003; Essington et al. 1996). 

RESOURCE INVENTORY 11
Figure 4. Vegetation. 

RESOURCE INVENTORY 12
The Colorado Natural Heritage Program (CNHP) has found that much of the xeric tallgrass 

prairies along the Colorado Front Range have been disturbed by urban and rural development 

over the last century. In addition, aggressive weed species such as cheat grass, Japanese brome,

and diffuse knapweed have degraded many areas of this community throughout the region 

(Essington et al. 1996). The CNHP believes that the xeric tallgrass grassland community exists 

in fewer than 20 places globally, and that Rocky Flats has the largest example of this community 

remaining in Colorado, and perhaps North America. For this reason, the CNHP has given this

community a G2/S2 rank, meaning that it is imperiled globally and within the state (Essington et 

al. 1996). 

The xeric tallgrass prairie community is comprised of several sub-communities (Nelson 2003). 

One of these sub-communities was identified by ESCO during a five-year evaluation of bluestemdominated grasslands in the Rocky Flats area. This study found that the major distinguishing 

feature of what ESCO calls the rare “Rocky Flats Bluestem Grassland” community is the 

simultaneous abundance of big bluestem, little bluestem, mountain muhly, and Porter’s aster. 

While big and little bluestem are characteristic of Midwestern tallgrass prairies, mountain muhly

and Porter’s aster are characteristic of mountain environments. This unusual combination of 

mountain and plains grassland species in a consistent and recurring pattern across the Rocky Flats 

alluvial surface, along with evidence of exceptional stability makes this vegetation community a 

rare, if not unique resource (ESCO 2002). 

At Rocky Flats, a Bluestem Grassland sub-community has been identified in sample plots in the 

upper Smart Ditch/South Woman Creek drainage and above the Rock Creek drainage near the 

border with the National Wind Technology Center (NWTC). All of these sites are within the 

larger xeric tallgrass grassland. The extent of this sub-community has not been mapped at the 

Rocky Flats site. ESCO believes the disappearance of Porter aster from some of the sample sites 

during the study is a result of herbicide spraying during on-going weed control efforts at Rocky 

Flats (ESCO 2002). 

Threats to the xeric tallgrass grassland community include exotic weed species, such as diffuse 

knapweed, the absence of grazing and fire to regenerate the grasslands, and the possibility of 

mining the Rocky Flats Alluvium that supports the xeric tallgrass prairie (PTI 1997a; Nelson 

2003). In its assessment of Rocky Flats bluestem grassland communities in the area, ESCO 

reported that restoring mined areas to support the presence of the dominant plant species appears 

to be feasible. However, ESCO also reported that the restoration of the full array of species and 

the ecological conditions that sustain them as a rare community (such as the soil mycorrhizae and 

RESOURCE INVENTORY 13
bacteria) is not technically feasible at this time and would require technical knowledge not presently available. To preserve the integrity of the xeric tallgrass grassland, ESCO recommended 

continued grazing (where appropriate) with reduced stocking rates alternating between summer

and winter/spring (ESCO 2002). 

Mesic Mixed Grassland 

The mesic mixed grassland community is the largest vegetation community at Rocky Flats, 

covering 2,199 acres across the broad ridges, hillsides, and valley floors throughout the site and 

the rolling plains in the eastern portions of Rocky Flats (Figure 4). This community is 

characterized by western wheatgrass, blue grama, side-oats grama, prairie junegrass, Canada 

bluegrass, Kentucky bluegrass, green needlegrass, and little bluestem. This grassland occurs on 

clay loam soils having relatively higher soil moisture content than other upland areas resulting 

from subirrigation from the coarse alluvial soils, snow accumulation, and protection from wind 

(DOE 1997). It is very important to wildlife species including grassland birds, small mammals, 

and larger mammals such as mule deer. 

The quality of mesic mixed grassland varies considerably across the site. In the western parts of 

the site, this community has been degraded by diffuse knapweed, while some areas in the eastern 

portion of the site have been degraded by weed species such as Japanese brome, alyssum, and 

musk thistle (PTI 1997a). 

Xeric Needle and Thread Grassland 

Several patches of xeric grassland dominated by needle-and-thread grass occur in the eastern half 

of Rocky Flats. These patches cover 187 acres. Other dominant grass species include New 

Mexico feathergrass, Canada bluegrass, Kentucky bluegrass, and Japanese brome (Nelson 2003). 

This grassland occurs primarily on the eastern extensions of the Rocky Flats pediment that is 

characterized by very cobbly sandy loam soils. Although not quite as cobbly, these soils are very

similar to the soils that support the xeric tallgrass grassland community (Kaiser-Hill 1997). The 

largest expanse of needle-and-thread grassland at Rocky Flats occurs along the ridgetop north of 

the east access road. 

Reclaimed Mixed Grassland 

Reclaimed mixed grassland covers 640 acres of the site. These grasslands are located primarily 

in the southeastern portion of the site, in areas that were formerly cultivated for agriculture. Most 

of these areas have been re-seeded with a mixture of smooth brome and intermediate wheatgrass, 

both introduced species. Other common species include crested wheatgrass, sweetclover, and 

field bindweed (Kaiser-Hill 1997). Compared to the native grasslands at Rocky Flats, the 

RESOURCE INVENTORY 14
reclaimed grassland has little plant and animal diversity. Grassland birds such as the western 

meadowlark and vesper sparrow use this community (PTI 1997a). 

Short Grassland 

This grassland is typified by buffalo grass and blue grama, both short grass prairie species. Ten

acres of this community are found on the site (Kaiser-Hill 1997). 

Shrublands 

Tall Upland Shrubland 

Tall upland shrubland occurs on 34 acres of north-facing slopes above seeps and along streams, 

primarily within the Rock Creek drainage. The tall upland shrubland consists of a rare 

association of hawthorn, chokecherry, and occasionally wild plum. This shrubland is associated 

with ground water seeps that form at the contact of the Rocky Flats Alluvium and the underlying, 

relatively impermeable Arapahoe Formation. The herbaceous understory contains a number of 

species that are restricted to the cool, shaded microhabitat provided by the canopy. Understory

species include Fendler waterleaf, spreading sweetroot, anise root, carrionflower greenbriar, 

fragile fern, Colorado violet, Rydberg’s violet, and northern bedstraw. Although the tall upland 

shrubland represents less than one percent of the total area of Rocky Flats, it contains 55 percent 

of the vegetation species on the site (DOE/FWS 2001). This shrubland community is believed to 

be rare, and may not occur anywhere else (DOE/FWS 2001; Essington et al. 1996). 

The tall upland shrubland community is threatened by exotic weeds that dominate the understory

of the shrubland in some areas. Diffuse knapweed in particular may be invading portions of the 

shrubland where accumulated dead knapweed plants have buried the shrubs. In one location, this 

accumulation is over 7 feet deep (PTI 1997b). Because of its reliance on ground water seeps, 

preservation of the alluvial ground water flows is essential to sustain this community (PTI 

1997b). 

Riparian Shrubland

Riparian shrubland forms extensive, dense thickets of shrubs along the stream bottoms. This 

community covers 41 acres throughout the Rocky Flats site. It is dominated by coyote willow 

and leadplant with a herbaceous understory. 

Other Shrubland 

Other shrubland communities include short upland shrubland and savannah shrubland, covering

70 acres primarily in the Rock Creek drainage. Short upland shrubland is characterized by

stands of snowberry and occasional Wood’s rose, and is often found in association with wet 

meadows and other wetland or riparian communities. Savanna shrubland occurs in dryer areas 

RESOURCE INVENTORY 15
where scattered shrubs are interspersed with grasslands. Sumac is the predominant shrub in this 

community (Kaiser-Hill 1997). 

Woodlands 

Riparian Woodland 

This riparian community is characterized by a diverse mixture of plains cottonwood, peach leaf 

willow, Siberian elm and coyote willow, with an understory of various shrubs such as leadplant 

and snowberry. Covering 28 acres, it is found primarily along the drainage bottoms of Rocky

Flats, with the most significant stand occurring in the Rock Creek drainage (Kaiser-Hill 1997;

PTI 1997a; Essington et al. 1996). The CNHP designates this community as the Great Plains 

riparian woodland complex.

The most significant threat to the riparian woodland community is from exotic weed species such 

as Canada thistle, musk thistle, smooth brome and Kentucky bluegrass. Preservation of this 

woodland community depends on the preservation of associated streamflow (PTI 1997a; 

Essington et al. 1996). 

Ponderosa Pine Woodland

Isolated patches of ponderosa pine woodland cover 9 acres in the uppermost reaches of the Rock 

Creek and Woman Creek drainages near the western edge of the site. These scattered pines 

represent an eastward extension of the nearby foothills forests. While much of the understory is

similar to the adjacent grassland communities, other associated plants are more likely to occur in 

foothills environments (DOE 1997). 

Wetlands 

Wetland communities cover 406 acres of the Rocky Flats site, and play an important role in 

sustaining the diverse vegetation and habitat types found on the site. The most significant 

wetland complexes at Rocky Flats are the seep-fed wetlands along the hillsides of the Rock Creek 

drainage, and the Antelope Springs complex in the Woman Creek drainage. These wetlands are 

significant because they have the largest contiguous areas, and the most complex plant 

associations (PTI 1997a). 

Three wetland types, tall marsh, short marsh, and wet meadow, are found at the site. These 

wetland types occur in streamside areas along the valley floors, and near the seeps and springs 

that occur along many of the hillsides. Each wetland type is described below. 

Tall Marsh Wetland 

Tall marsh wetlands generally occur along ponds, ditches, and in persistently saturated seeps. 

Covering 31 acres of the site, these wetlands are dominated by cattails, bulrushes, and associated 

RESOURCE INVENTORY 16
forbs such as watercress, showy milkweed, swamp milkweed and Canada thistle (a noxious 

weed). Antelope Springs in the Woman Creek drainage is the best example of a saturated slope 

wetland and tall marsh community at Rocky Flats. 

Short Marsh Wetland 

Covering 121 acres, this wetland type is commonly associated with seasonally inundated or 

saturated areas, such as hillside seeps. Prevalent species include Nebraska sedge, Baltic rush, and 

spike rush as well as forbs such as watercress and speedwell. Many hillside seeps also support 

the rare tall upland shrubland community. 

Wet Meadow Wetland 

These seasonally saturated wetlands occupy 254 acres on the perimeter of saturated wetlands and 

contain elements of both the short marsh wetland and upland mixed grassland communities. 

Prevalent species include redtop, prairie cordgrass, and solid stands of Canada bluegrass and 

western wheatgrass. Other key plants include common milkweed, wild iris, Canada thistle, dock 

and occasionally arnica (Nelson 2003). 

Noxious Weeds 

Noxious weeds are exotic, aggressive plants that invade native habitat and cause adverse 

economic or environmental impacts. Since 1990, the site has experienced a large increase in 

noxious weeds (DOE 1999). The noxious weed species at Rocky Flats with the greatest potential 

to degrade the native plant communities and are the most difficult to control include diffuse 

knapweed, musk thistle, dalmation toadlfax, Canada thistle, and St. Johnswort. Diffuse 

knapweed, an aggressive tumbleweed, is currently given highest control priority. Canada thistle 

is common in and around most of the wetlands, musk thistle is sparse but widespread across 

mesic grasslands, and dalmatian toadflax is common in xeric grasslands and other areas. 

Prioritized noxious weed lists and selected weed control measures are found in the 2002 Annual 

Vegetation Management Plan. The three most abundant noxious weeds identified in 2001

mapping were: dalmatian toadflax infesting 2,504 acres; diffuse knapweed infesting 1,919 acres; 

and musk thistle infesting 869 acres (Table 2 and Figure 5) (Kaiser-Hill 2002a; DOE/FWS 2001). 

RESOURCE INVENTORY 17
Figure 5. Noxious Weeds. 

RESOURCE INVENTORY 18
Table 2. Major Noxious Weeds at Rocky Flats.

Weed Name High Density 

(acres)

Medium

Density 

(acres) 

Low Density 

(acres) 

Scattered 

Density 

(acres) 

Total 

Infested 

Area 

(acres) 

Dalmation toadflax 23 743 612 1,128 2,504 

Diffuse knapweed 294 430 512 683 1,919 

Musk thistle 129 131 247 362 869

DOE’s Current Weed Management 

Weed control measures currently used by DOE at Rocky Flats include biological controls 

(insects), physical or mechanical controls (grading and mowing), and chemical controls 

(herbicides). Biological controls are used in areas where other forms of weed control are 

impractical, such as riparian areas, and to complement other methods. Mechanical controls such 

as mowing are used along roadsides and near structures, while hand pulling and sickles are used 

to control some small weed infestations. 

Chemical controls are used through much of the site to control persistent weed species. The 2002 

Annual Vegetation Management Plan (Kaiser-Hill 2002a) prescribes spot herbicide applications 

for species such as scotch thistle and others. Larger areas that are dominated by diffuse 

knapweed, Russian knapweed, dalmatian toadflax, or musk thistle are controlled using aerial and 

ground application. About 48 acres were treated by ground application in 2002, while about 840 

acres were treated by aerial herbicide application. Some of the more commonly used herbicides 

include Tordon 22K, Transline, Telar, and Roundup (Kaiser-Hill 2002a). 

While aerial and broadcast herbicide application may encroach near Preble’s meadow jumping 

mouse protection areas, Kaiser-Hill determined that there will be no adverse effect on the mouse 

(Kaiser-Hill 2002a). According to the Vegetation Management Plan, aerial herbicide application 

is restricted within 100 feet of riparian vegetation, and broadcast applications are restricted within 

30 feet of Preble’s mouse habitat. Drift cards are used to monitor wind-induced drift of 

herbicides near sensitive areas. Broadleaf herbicides to affect only target species and have no 

metabolic impact on wildlife have been selected. Therefore, even direct exposure of wildlife to 

the dilute compound would not risk mortality or solicit other adverse responses. The use of 

selective herbicides is expected to improve long-term habitat conditions for the mouse (KaiserHill 2002a; Nelson 2003). Herbicides are approved for use and used by Kaiser-Hill Ecology

Group staff in accordance with the 1999 Vegetation Management Environmental Assessment

(DOE 1999), and Annual Vegetation Management Plans. 

RESOURCE INVENTORY 19
The use of prescribed burns and grazing on Rocky Flats grasslands was suggested by the KaiserHill Ecology Group as a management tool to help control weeds, reduce plant litter, recycle 

nutrients, and improve the health and vigor of the native plant communities. Under current 

policies however, grazing is not permitted at Rocky Flats and all prescribed burns are “on hold” 

(Kaiser-Hill 2002a). In the 1999 Vegetation Management Environmental Assessment (EA), DOE 

found that intensively managed grazers may be effective in reducing weed populations in selected 

areas. However, it also explained that this tool would not be used because of the lack of staff and 

equipment that would be required to effectively implement grazing (DOE 1999). Prescribed 

burns are further described in the Fire History and Management section. 

Fire History and Management 

Historical documentation indicates that the grasslands in the Rocky Flats area have been 

subjected to lightning and human-caused fires for thousands of years. These fires are believed to 

have played a major role in promoting native vegetation growth and diversity. Since 1972 

wildfires have not been allowed to burn and only one controlled burn has been conducted in the 

grasslands at Rocky Flats. As a result, a fuel load of dead vegetation has been building up in the 

grasslands of Rocky Flats for at least 30 years. This buildup of dead vegetation has contributed to 

an invasion of noxious weeds on the site, particularly in the last 10 years (DOE 1999). 

Seven wildfires have been documented on the site since 1993. In 1994, the Spring Grassland fire 

burned 70 acres between Highway 128 on the north boundary and the north access road. In 1996, 

the 104-acre Labor Day Grassland Fire burned much of an area penned in by access roads in the 

southern portion of the site. In February 2002, a 27-acre fire burned through portions of the Rock 

Creek drainage on the south side of Highway 128. As mentioned below, a 48-acre prescribed

burn was conducted on April 6, 2000. The prescribed burn took place in the same area as the 

1996 wildfire (Kaiser-Hill Ecology Group 2002). 

Prescribed Burns 

As outlined in the 1999 Vegetation Management EA, prescribed burns can be used to stimulate 

native vegetation growth and supplement other weed control efforts (DOE 1999). In 2000, a 48-

acre test burn was conducted on the xeric tallgrass prairie south of the Industrial. While the burn 

is reported to have shown positive results (Kaiser-Hill 2002a), no additional prescribed burns 

have been conducted since 2000, and none are planned. The present rationale for not pursuing 

additional prescribed burns at Rocky Flats is that in the face of public outcry about the 2000 burn, 

RESOURCE INVENTORY 20
DOE prefers to wait until cleanup measures are completed and Service management plans are in 

place (Nelson 2003). 

Wildlife 

Many areas of the Rocky Flats site have remained relatively undisturbed for the last 30 to 50 

years, allowing them to develop diverse habitat and associated wildlife. These wildlife 

communities are supported by the regional network of protected open space that surrounds the 

site on three sides, buffering wildlife habitat from the surrounding urban development. 

Mammals 

One of the most abundant and conspicuous mammal species at Rocky Flats is the mule deer. A 

resident herd of about 160 individuals inhabits the site. While mule deer concentrations vary by

the season, they appear to have a general preference the following areas (shown in Figure 6): 

• The open grasslands of the upper Rock Creek drainage 

• The shrublands of the lower Rock Creek drainage 

• The grasslands of the upper Walnut Creek drainage 

• The hillsides above lower Walnut Creek 

• Riparian bottomlands around Woman Creek and Antelope Springs

• The grasslands below the pediment in the Smart Ditch drainage1 

In the spring, mule deer exhibit an affinity for woody habitat, and secondarily for grasslands. In 

the summer, deer use is more generally divided among different habitats. In the fall, mule deer 

primarily use woody habitats, with grasslands also being important. In the winter, mule deer are 

commonly observed in grasslands and tall upland shrublands (Kaiser-Hill 2001). 

Whitetail deer have become more common at the site, and are often observed in company with 

mule deer. American elk are known to visit Rocky Flats, but are not considered to be resident 

(DOE 1997).

Other mammals commonly observed at Rocky Flats include desert cottontail, muskrat, and 

porcupine. Muskrats generally occur in and around the ponds, while porcupine populations are 

limited to the shrubland and ponderosa pine habitats in the upper Rock Creek drainage. Blacktailed prairie dogs inhabit the Rocky Flats site in limited numbers (Figure 6), and are discussed 

below under Federal Threatened Endangered and Candidate Species. Numerous small mammal 

species, such as mice and voles, inhabit all vegetation community types at Rocky Flats. Preble’s

 

1 Based on seasonal surveys conducted by Kaiser-Hill Ecology Group staff between 1997 and 2001.

RESOURCE INVENTORY 21
meadow jumping mouse, a threatened species, is described below under Federal Threatened 

Endangered and Candidate Species. 

Two commonly observed carnivore species at Rocky Flats are the coyote, which occurs 

throughout the site, and raccoon, which is often seen in the Industrial Area and near watercourses. 

There are typically three to six coyote dens at Rocky Flats, supporting an estimated 14 to 16 

individuals at any given time (Kaiser-Hill 2001). 

Twenty-two coyote dens used between 1991 and 2002 have been identified at Rocky Flats. The 

coyote dens generally occur on hillsides near watercourses. Six dens were active in 2002. One 

active den was located in the upper Rock Creek drainage, two were located on the slopes above 

either side of Walnut Creek near Indiana Street, one was near the D-1 pond, one near Antelope 

Springs, and one in the upper South Woman Creek drainage (Nelson 2003). 

Other carnivores include striped skunk, gray fox, red fox, long-tailed weasel, American badger 

and mink. Black bears and mountain lion tracks are occasionally observed at the site (Kaiser-Hill 

2000; Kaiser-Hill 2001). 

Birds 

The most commonly observed raptors at Rocky Flats are red-tailed hawk, great horned owl, and 

American kestrel. Other less abundant raptors include Swainson’s hawk, ferruginous hawk, 

prairie falcons, and long-eared owls. Most raptor species use riparian woodlands or tall upland

shrublands for nesting and roosting habitat, and forage in all habitats at the site. Raptor nest sites 

observed between 1991 and 1998 are shown on Figure 6. 

Over 185 species of migratory birds have been recorded at Rocky Flats, of which about 75 are 

believed to breed at the site. Of the estimated 100 neotropical migrants (migratory birds that 

breed north of the U.S./Mexico border and winter south of the border (PTI 1997a)) at Rocky

Flats, about 45 are confirmed or suspected breeders at the site. Commonly observed bird species 

in wetland habitats include the red-winged blackbird, song sparrow, common yellowthroat, and 

common snipe. Common birds in riparian woodland areas include the northern oriole, American 

goldfinch, house finch, and yellow warbler. The tall upland shrubland habitat is inhabited by the 

song sparrow, rufus-sided towhee, black-billed magpie, yellow-breasted chat, and black-capped 

chickadee. Common grassland birds include the vesper sparrow, western meadowlark, 

grasshopper sparrow, and mourning dove (DOE 1997). 

RESOURCE INVENTORY 22
Figure 6. Wildlife Resources. 

RESOURCE INVENTORY 23
Several waterfowl species are found in the ponds at Rocky Flats. The most common waterfowl 

are mallards and Canada geese (DOE 1997). Great blue herons feed in mudflats and short 

marshlands, while double-crested cormorants are common summer residents. 

The plains sharp-tailed grouse is extirpated from the area and is not known to occur at Rocky

Flats (DOE 1997). However, the Rocky Flats site and surrounding areas contain potential habitat 

for the grouse. The City of Boulder Open Space and Mountain Parks Department, along with 

Boulder County Parks and Open Space and the Colorado Division of Wildlife (CDOW) have

recently begun a sharp-tailed grouse reintroduction program on joint City-County owned open 

space land north of Rocky Flats. Wildlife officials transplanted five individuals in 2003. 

Additional grouse reintroductions are planned in the future (Brennan 2003). 

Reptiles and Amphibians 

In general, reptiles and amphibians are found in limited numbers at Rocky Flats due to an absence 

of suitable habitat. The most common reptiles are the bullsnake, yellow-bellied racer, Western

plains garter snake, and prairie rattlesnake. All of these species occur in the open grassland 

habitats, although the garter snake typically lives close to water bodies. Other reptiles include the 

short-horned lizard in open grasslands, the eastern fence lizard in rocky shrublands, and the 

western painted turtle in ponds (DOE 1997). 

The most abundant amphibian at Rocky Flats is the boreal chorus frog, which breeds in water 

bodies throughout the site. The northern leopard frog is less common, and is found only in 

permanent water bodies such as ponds (DOE 1997). The boreal chorus frog is relatively

abundant in the streams and wetlands at Rocky Flats (Kaiser-Hill 2000). Other amphibians 

include the bullfrog, Woodhouse’s toad, the plains spadefoot, and the tiger salamander (DOE 

1997). 

Aquatic Species 

Aquatic species at Rocky Flats are limited by the low and irregular flows of most of the drainages 

and ditches. The most common aquatic macroinvertebrates are the larvae of the blackfly, midge, 

and mayfly (DOE 1997). Other species include caddisflies, craneflies, damselfly larvae, as well 

as snails and amphipods. Large macroinvertebrates such as crayfish and snails are potentially

important prey for other fish, waterfowl and mammal species. 

Each of the three primary drainages at Rocky Flats contain a variety of pond and stream habitats, 

varying amounts of habitat modification and seasonal water flows. 

RESOURCE INVENTORY 24
Fish habitat in Rock Creek is located in and around the Lindsay Ranch complex. In the Linday 

Ranch area, water flows are currently intermittent, and preclude the establishment of permanent 

fish populations. As part of the objectives of the Rock Creek Integrated Natural Resources 

Management Plan (2001), largemouth bass were removed from Lindsay Pond with rotenone in 

2002. By August 2003, northern redbelly dace and possibly common shiner will be introduced 

to Lindsay Pond to establish a refugia for these declining Colorado native fish species. 

The Walnut Creek drainage has been highly modified as part of the development of the Rocky 

Flats. The upper section of the drainage was filled, and the lower section modified into a series 

of small reservoirs that can retain water released from the industrial area. A variety of nonnative fish species (rainbow trout, carp, bass) were introduced into the Walnut Creek reservoirs. 

Although all introductions did not establish reproducing fish populations, records indicate that 

carp, goldfish and fathead minnows are present within these reservoirs. Additional sampling of 

these reservoirs should be completed in 2003, as part of the program to restore the reservoirs. 

Woman Creek retains a significant amount of stream habitat, and holds the majority of Rock Flats 

fish species. Native fish species known to maintain reproducing populations within Woman 

Creek include white suckers, fathead minnows, green sunfish, stonerollers and creek chubs. 

Two non-native fish species, golden shiners and largemouth bass, have also been reported in the 

drainage. 

Wildlife Species of Special Concern 

In addition to federally listed wildlife species described below in the Federal Threatened, 

Endangered and Candidate Species section, the Rocky Flats site has been known to support 

numerous species with special status designated by the U.S. Fish and Wildlife Service, the 

CDOW, or the CNHP because of their rare or imperiled status. These species are included in 

Table 3. 

RESOURCE INVENTORY 25
Table 3. Wildlife Species of Special Concern at Rocky Flats. 

Common Name Scientific Name Status Occurrence at 

Rocky Flats 

Small-footed myotis Myotis subulatus = M. 

ciliolabrum

Federal special concern Observed Infrequently 

Eastern short horned

lizard 

Phrynosoma douglassii 

brevirostra

Federal special concern Known resident or

regular visitor 

Northern leopard frog Rana pipiens State special concern Observed Infrequently

Northern goshawk Accipiter gentilis Federal special concern Observed Infrequently 

White-faced ibis Plegadis chihi Federal special concern Known resident or

regular visitor 

Baird’s sparrow Ammodramus bairdii Federal special concern Observed Infrequently 

Western burrowing owl Athene cunicularia

hypugea

Federal special concern, 

State threatened

Known resident or

regular visitor 

Ferruginous hawk Buteo regalis Federal/State special 

concern 

Known resident or

regular visitor 

Black swift Cypseliodes nige Federal special concern Observed Infrequently 

Loggerhead shrike Lanius ludovicianus Federal special concern Known resident or

regular visitor 

Long-billed curlew Numenius americanus State special concern Observed Infrequently 

Greater sandhill crane Grus canadensis tibida State threatened Observed Infrequently 

American white pelican Pelecanus 

erythrorhynchos 

State special concern Observed Infrequently 

Some of the species of special concern that are known residents or regular visitors to Rocky Flats 

are briefly described as follows. The eastern short horned lizard occupies grassland areas at 

Rocky Flats. The white-faced ibis are found in mudflats or grassy areas near open water. 

Western burrowing owl have been observed in grasslands. Ferruginous hawk and northern 

goshawk have been observed in riparian woodlands. Loggerhead shrike is suspected to breed in 

shrublands (PTI 1997a; DOE 1997). 

Federal Threatened, Endangered and Candidate Species 

Rocky Flats supports several wildlife species that are listed as threatened, endangered, or 

candidate species under the Endangered Species Act (ESA). Two federally listed wildlife species 

known to occur at the site are the Preble’s meadow jumping mouse and the bald eagle. The 

black-tailed prairie dog is a candidate species. 

RESOURCE INVENTORY 26
Preble’s Meadow Jumping Mouse 

Preble’s meadow jumping mouse occurs in every major drainage on the site. Listed as a 

threatened species in 1998, the mouse occurs in habitat adjacent to streams and waterways along 

the Front Range of Colorado and southeastern Wyoming. At Rocky Flats, the mouse also has 

been found in wetlands and shrubland communities adjacent to the Rock Creek and Woman 

Creek drainages. The natural history and ecology of the Preble’s is not well known, and an 

increase in knowledge about the species may change what is known about their habitat needs and 

associations. 

In 2002, the U.S. Fish and Wildlife Service proposed critical habitat for the mouse throughout its 

range. The proposed critical habitat along the Colorado Front Range is defined as a variable 

distance from the edges of small streams (depending on stream order and size) (FWS 2002a). At 

Rocky Flats, the proposed critical habitat includes most of Rock Creek and its lower tributaries, 

the middle and south branches of Walnut Creek, the entire length of Woman Creek across the 

site, and the lower reaches of the South Woman Creek/Smart Ditch drainage. The proposed 

critical habitat will not likely include habitat in minor tributaries or associated with hillside seeps. 

Preble’s populations have also been found along Coal Creek on City of Boulder Open Space 

lands to the west and north of Rocky Flats (BOSMP 2002). Other populations are known to 

occur on Ralston Creek to the south-southwest of Rocky Flats. 

Bald Eagle

The bald eagle occasionally forages at the site. No nests have been identified at Rocky Flats. 

The bald eagle was federally listed as endangered in 1967, and was downlisted to threatened in 

1994. An active nest is located to the east of Rocky Flats near Standley Lake. Eagles feed 

primarily on fish and waterbirds but also on small mammals and mammal carcasses (DOE/FWS 

2001). 

Black-tailed Prairie Dog

The black-tailed prairie dog is a candidate for listing as a threatened species. Candidate species

are plants and animals for which FWS has sufficient information on their biological status and 

threats to propose them as endangered or threatened under the ESA, but for which development 

of a proposed listing regulation is precluded by other higher priority listing activities. Candidate 

species receive no statutory protection under the ESA (FWS 2002b). 

Three black-tailed prairie dog colonies were mapped at Rocky Flats in 2000. A large colony is

located near the eastern edge on the southwest side of the east entrance gate. One smaller colony

RESOURCE INVENTORY 27
Figure 7. Potential Prairie Dog Habitat 

RESOURCE INVENTORY 28
 exists along the northern border along Highway 128, and another along the southern border near 

Big Dry Creek. These colonies are shown on Figures 6 and 7. 

The Rocky Flats site contains about 2,460 acres of potential prairie dog habitat (Figure 7). Prairie 

dogs are known to prefer the following habitat attributes (Clippinger 1989): 

• 30 to 90 percent herbaceous cover 

• 2- to 10-inch vegetation height 

• Slopes less than 20 percent (prefer less than 10 percent) 

• Rock-free soils with less than 70 percent sand content 

The potential prairie dog habitat shown in Figure 7 is based on soils, vegetation, and slope. It 

should be noted that prairie dogs have been known to occur in other areas of the site, where 

habitat conditions are marginal due to stony soils or tallgrass grasslands. However, over the long 

term, prairie dogs at Rocky Flats are most likely to successfully colonize those areas that provide 

preferable habitat conditions, as shown in Figure 7. 

The xeric tallgrass prairie community at Rocky Flats is not considered to be prairie dog habitat 

primarily because the vegetation height impacts their need for open vistas. In addition, the warm

season grasses that dominate the tallgrass prairie do not maintain their nutritive value in 

dormancy. Because prairie dogs do not migrate seasonally, the tallgrass prairie may be unable to 

sustain prairie dog populations through the winter (City of Boulder 1996). 

Plant Species 

No federally listed plant species are known to occur at Rocky Flats. While many of the riparian 

and wetland communities support potential habitat for the Ute ladies’-tresses orchid and Colorado 

butterfly plant, these species are not known to occur at the site (ESCO 1994). The mosaic of 

vegetation communities at Rocky Flats contains several rare and sensitive plant communities. 

These include the xeric tallgrass grassland, tall upland shrubland, riparian shrubland, and plains

cottonwood riparian woodland communities. Each of these communities is described in detail in 

the Vegetation section. 

Cultural and Historical Resources 

Cultural resource surveys have identified and recorded 45 cultural or historical sites or artifacts at 

the Rocky Flats site. Most of these sites or artifacts are related to Euro-American occupation of 

the area within the last 120 years. None of the identified cultural resources are recommended as 

eligible for listing on the National Register of Historic Places. 

RESOURCE INVENTORY 29
Prehistoric Resources 

While it is apparent that various Native American groups occupied the Rocky Flats region prior 

to 1800, there are few material remains from this period on the site. Cultural resource inventories 

have identified several isolated finds of prehistoric origin, including stone enclosures and stone 

cairns. Two rectangular stone enclosures dating from the Early Ceramic period (AD 1-1000) 

were located at the Lindsay Ranch site in 1971. In addition a projectile point of Early Ceramic 

affiliation, a piece of ground stone and chipped stone have been recorded (Dames & Moore 

1991).

Historic Resources 

Numerous sites and artifacts related to agricultural and mining activity at Rocky Flats in the early

20th century have been identified. These sites include ditches, stock ponds, rock piles, building 

remains, fencing materials, and other farming and ranching-related equipment (Figure 8). An 

abandoned railroad grade, whose construction began in 1881 and was never completed, traverses 

the upper tributaries of Rock Creek in the northwestern corner of the site. 

While there are few historic sites at Rocky Flats reflecting Native American occupation or EuroAmerican activities prior to 1900, there are many sites related to the land uses at Rocky Flats 

during the early 20th century. During this time, the cattle industry along the Front Range boomed, 

and several families began to acquire land for pasture in the Rocky Flats area. In most cases, the 

primary ranch sites were located outside of what became the Rocky Flats site, with the exception 

of the Lindsay Ranch (Dames & Moore 1991). 

Lindsay Ranch 

The area that is known as the Lindsay Ranch was originally homesteaded by the Scott family in

1868. The northern part of the Lindsay Ranch area was given to the railroad in 1897 as part of

the railroad land grants. Other lands surrounding what became the Lindsay Ranch were 

homesteaded by various settlers in the 1880s and 1890s. Between the late 1880s and 1916, the 

Jones family, one of the original homesteaders in the area, had acquired the area that would 

become the Lindsay Ranch. During this time, many of the original homesteads were being 

consolidated into larger parcels to provide pasture for cattle. 

RESOURCE INVENTORY 30
Figure 8. Cultural Resources. 

RESOURCE INVENTORY 31
In 1916, almost 700 acres of land in the area was sold to the Ebertarter family, who controlled 

1,280 acres along the northern portion of the current Rocky Flats site. The land was sold to G. 

Lindsay in 1941. Ten years later, the U.S. Atomic Energy Commission purchased the Lindsay

Ranch for the creation of Rocky Flats (Dames & Moore 1991). 

Cold War Era 

The Rocky Flats site was one of the 13 nuclear weapons production facilities in the United States 

during the Cold War. Weapons production ended in 1989. The DOE completed a inventory of

all buildings on the site and determined 64 facilities within the Industrial Area are very important 

to regional, national, and international history for their role during the Cold War era. The State 

Historic Preservation Office has determined that these 64 facilities are eligible for the National 

Register of Historic Places as a historic district (DOE 1997). All of these facilities will be 

removed before site closure. 

Infrastructure, Easements, and Utilities 

Transportation 

The Rocky Flats site is surrounded on all sides by State highways and a major thoroughfare. 

Colorado State Highway (SH) 128 defines most of the site’s northern boundary, while SH 93 runs 

parallel to the western boundary about 1⁄4 mile to the west. Less than 1 mile to the south, SH 72 

runs parallel to the site’s southern boundary. Indiana Street defines the site’s eastern boundary. 

Indiana Street currently has a right-of-way width of 50 feet. Access to the site is from SH 93 or 

Indiana Street. Outside of the Industrial Area, which currently contains a network of paved 

streets, most of the site is accessed by a network of graded gravel roads and minor two-track 

roads (Figure 9). 

The Rocky Flats site currently has many roads, fences and utilities that serve its pre-closure 

functions. In addition, there are existing mineral rights and water rights on site that are owned by 

outside entities. Existing infrastructure, utility easements, and mining permits are shown on 

Figure 9. 

Utilities 

The utility infrastructure currently serving the site, including electric, natural gas, and sewer lines, 

will be removed or remediated in place prior to closure. According to the Rocky Flats National 

Wildlife Refuge Act, existing, privately-owned utility easements across the site will remain in 

place, and the owners of those easements will have the right to continue to access their property. 

RESOURCE INVENTORY 32
Figure 9. Infrastructure, Easements and Utilities. 

RESOURCE INVENTORY 33
Natural Gas Easements 

Two natural gas easements are currently on the site, a north-south easement and an east-west 

easement. The north-south easement runs through the eastern portion of the site. The east-west

easement runs along the southern edge of the Industrial Area, extending between the east and 

west access gates (Figure 9). In an area east and south of the Industrial Area, the title to portions 

of both natural gas easements is unclear (Schiesswohl 2003). 

Electrical Line Easements

A 230-kV electrical line follows an easement through the southern and eastern portions of the 

site. The line runs in a north-south orientation between the north boundary and the proximity of 

South Woman Creek, where it then runs southwesterly towards the southern boundary of Rocky

Flats. A second electrical line easement runs from the proximity of the C-2 pond to the east gate 

along Indiana Street. 

Two parallel 115-kV electrical lines follow easements from the northeast corner of Rocky Flats 

towards the Industrial Area. These lines were constructed primarily to serve the Rocky Flats

Industrial Area, and will be removed and easements abandoned prior to site closure. Another 

electrical line easement follows the west access road from Highway 93 to the Industrial Area. 

This electrical line has been removed, and the easement will be abandoned (the title to this 

easement is unclear). These easements are shown on Figure 9. An electrical line with no 

easement follows the west side of Indiana Street, within the Rocky Flats boundary. 

Other Utilities

A fiber optic line with an easement runs from the NWTC in the northwest corner of the site, 

across the Rock Creek drainage, to the Industrial Area. The future of this line and easement is 

uncertain. In addition to the electrical line along the west side of Indiana Street, a telephone and 

fiber optic line also follows the Indiana right-of-way. These utility lines do not have easements,

and may be located within the Rocky Flats site (instead of the Indiana right-of-way) (Schiesswohl 

2003). 

Mineral Rights 

The U.S. Government does not own all of the subsurface mineral rights at the Rocky Flats site. 

As shown in Figure 9, there are currently two permitted mining areas at Rocky Flats: 

• Bluestone Sand and Gravel mine – 425 acres 

• Lakewood Brick and Tile – 80 acres 

RESOURCE INVENTORY 34
LaFarge, Inc. (formerly Western Aggregates) operates the Bluestone sand and gravel quarry in 

the northwestern corner of the site. While the permit boundary includes 425 acres of land, about 

300 of those acres are designated for habitat preservation, or non-mining setback, easements and 

buffer areas (Jefferson County 2002). The Bluestone permit allows expansion of the mine into 

the northern portion of the Rock Creek drainage, near the NWTC (Figure 9). Most of the Rock 

Creek drainage is included in a habitat preservation area. 

Lakewood Brick and Tile operates the 80-acre clay mining area immediately north of the west 

access road. On the east side of the Lakewood Brick and Tile pit, a mining permit for the Church 

Pit was preliminarily approved by the state in 1987. However, the permit for the Church Pit has 

not been completed (Schiesswohl 2003; Mount 2003). 

Water Rights 

As discussed in the Water Resources section, the current water supply to the Rocky Flats site will 

be terminated following the cleanup and closure of the existing facilities. There are currently no 

plans for a new water supply to serve the Rocky Flats NWR. The U.S. Government does not 

own water rights on the Rocky Flats site. However, two outside entities do own water rights. 

The Smart Ditch and Irrigation Company owns water rights through the Smart Ditch from Rocky

Flats Lake (west of the site) to the D-2 Pond in the southeast corner. The City and County of

Broomfield owns water rights in the Upper Church Ditch and the McKay Ditch, which convey 

water across the site to the east and northeast. Other water rights on the site include the Mower 

Ditch and the Kinnear Ditch (Advanced Sciences 1991). 

Surrounding Land Use 

The Rocky Flats site is located at the intersection of Jefferson, Boulder, and Broomfield counties. 

The site is surrounded by open space to the north, east, and west, and urban development to the 

northeast and southeast (Figure 10). Other nearby land uses include mining operations, wind 

energy research, and water collection and storage facilities. 

Municipalities 

Four principal cities and towns, Arvada, Westminster, Broomfield, and Superior, are located 

within close proximity of Rocky Flats. The general land uses of those portions of these 

municipalities located near the site are described below. 

The City of Arvada is located southeast of Rocky Flats. While most of Arvada’s residential and 

commercial development is located over 1 mile from Rocky Flats, the City’s incorporated 

boundary directly abuts the site. A large area immediately south of Rocky Flats and east of 

RESOURCE INVENTORY 35
Highway 93 has been annexed by the City, and is planned for residential and mixed development. 

This area, known as the Vauxmont property, is currently vacant and used for livestock grazing. 

North of Arvada, the City of Westminster is located directly east of Rocky Flats. However, most 

of the western portions of Westminster’s incorporated area consist of open space. Residential 

land uses begin about 1.5 miles east of Rocky Flats. 

The City and County of Broomfield is located immediately east and northeast of Rocky Flats. 

The area to the east is dominated by open space associated with Great Western Reservoir and 

vacant land. Other portions of this area are planned for development supporting office 

complexes. An existing office complex is located about 1 mile northeast of Rocky Flats on the 

north side of Highway 128.

The Town of Superior is located to the north and northeast of Rocky Flats’ northeastern corner. 

Existing residential land uses are located about 1⁄4 mile to the north of Rocky Flats, while future

residential developments are proposed for the area. Superior’s town center is located about 2 

miles north of the Rocky Flats boundary. 

Woman Creek Reservoir Authority

The Woman Creek Reservoir Authority is a separate unit of government comprised of the cities 

of Westminster, Thornton, and Northglenn. The Authority constructed the Woman Creek 

Reservoir in 1996 to prevent the flow of surface water from Rocky Flats into Standley Lake, a 

drinking water source for several communities (CDPHE 2003). The Woman Creek Reservoir 

Authority owns the reservoir and some of the land surrounding the reservoir. 

Open Space 

The Rocky Flats site is surrounded on three sides by designated open space. These open space 

lands are owned and managed by seven different jurisdictions. These areas are described in detail 

in the Open Space, Recreation and Trails section. 

Other Nearby Land Uses 

The Colorado State Land Board manages state land in Section 16 immediately adjacent to Rocky 

Flats to the southwest. Portions of Section 16 have been mined for clay and aggregates, while

most of the land is leased for grazing livestock. 

The Department of Energy’s National Renewable Energy Laboratory operates the National Wind 

Technology Center immediately adjacent to Rocky Flats to the northwest. This facility is used 

for research on power-generating wind turbines. 

RESOURCE INVENTORY 36
Denver Water owns a large tract of land about 1 mile to the southwest of Rocky Flats along the 

west side of Highway 93 from Highway 72 south to Ralston Reservoir. While portions of this

land are used for water collection and distribution facilities, most of it is undeveloped. This 

property includes a potential reservoir site in Leyden Gulch (Bassett 2002). 

Two companies, TXI and LaFarge, operate gravel mining and processing facilities on two 

separate but contiguous sites in the northwest corner of Rocky Flats site and on adjacent 

privately-owned land. The mining facilities consist of surface excavations, material conveyors, 

rail lines, and processing facilities (DOE-NREL 2002).

Jefferson County Airport is located about 2 miles east of Rocky Flats. Airport runways are 

aligned in a northeast/southwest configuration. Aircraft takeoff and landing patterns currently do 

not pass directly over the Rocky Flats site (DOE-NREL 2002). 

Open Space, Recreation and Trails 

Rocky Flats is surrounded on three sides by designated open space. While some of these open 

space parcels restrict public use, others provide a network of recreational trails that are connected 

to the surrounding communities (Figure 10). 

City of Boulder Open Space and Mountain Parks 

The City of Boulder Open Space and Mountain Parks (BOSMP) owns and manages several large 

open space parcels near the northern and western edges of Rocky Flats. BOSMP lands along the 

northern edge of Rocky Flats extend from near the middle of Rocky Flats to the west along the 

Boulder/Jefferson county line for over 4 miles to the top of Eldorado Mountain. These lands are 

collectively referred to as South Boulder Open Space. Within Jefferson County, BOSMP also 

owns the Jewell Mountain and Van Fleet properties to the west of Rocky Flats between Highway

93 and Coal Creek. 

BOSMP lands offer a network of soft-surface trails available for hiking, mountain biking, and 

equestrian use. The Flatirons Vista and Greenbelt Plateau trailheads are located about 1 mile 

from Rocky Flats to the northwest near the Highway 93/128 intersection. 

Most BOSMP lands near Rocky Flats permit livestock grazing. The Jewell Mountain Property to 

the west of Rocky Flats and other properties along Coal Creek are grazed during the summer 

(BOSMP 2002). 

BOSMP is working with several other organizations to protect and restore the Coal Creek riparian 

area that runs through their properties near Rocky Flats. Restoration activities include fencing to 

RESOURCE INVENTORY 37
Figure 10. Regional Open Space and Trails. 

RESOURCE INVENTORY 38
control livestock, stream channel restoration, wetland restoration, and monitoring. Small 

mammal trapping along Coal Creek has revealed several occurrences of Preble’s meadow 

jumping mouse (BOSMP 2002). 

Boulder County Open Space 

Boulder County owns several open space parcels on the north side of Rocky Flats between the 

Town of Superior to the east and BOSMP lands to the west. These holdings include the Lindsay, 

Zacharias/Thomas, and Carlson/Lastoka properties. Recreational access to Boulder County Open 

Space lands to the north and northeast of Rocky Flats is from the Coalton Trail, which begins on 

Highway 128 north of Rocky Flats. This trail joins the Rock Creek Trail in the Town of Superior. 

Jefferson County Open Space 

Jefferson County owns and manages several parcels to the west and southwest of Rocky Flats. 

The Ranson-Edwards property immediately west of Rocky Flats extends from Coal Creek to the 

west. Coal Creek Canyon Open Space is located along the south side of Highway 72 about 2 

miles west of Rocky Flats. Jefferson County also owns several conservation easements in this 

area. White Ranch Open Space is located about 3 miles to the southwest of the site. 

The 2,807-acre Coal Creek Canyon Park currently has no developed trails or facilities. The park 

is divided into three management unit designations. The Parkland Recreation Area is intended 

for a trailhead and other facilities along Highway 72. The Natural Area management unit 

comprises most of the park area and includes an area of xeric tallgrass prairie. This area also will 

be managed for natural surface trail opportunities. The Sensitive Area along Coal Creek contains 

a population of Preble’s meadow jumping mouse, whose suitable habitat extends west into Coal 

Creek Canyon. Due to uncertainties surrounding the future management of other publicly owned 

properties in the immediate area, including Rocky Flats and Denver Water properties, the 

Management Plan for this property recommends postponing any trail or facility development for 

5 to 7 years (JCOS 2001).

Eldorado Canyon State Park 

Eldorado Canyon State Park is located about 2 miles northwest of Rocky Flats, where South 

Boulder Creek bisects the Front Range. The park offers world-class rock climbing, picnic 

facilities and several soft-surface trails available for hiking, mountain biking, and equestrian use. 

City of Arvada Open Space 

The City of Arvada owns several open space parcels about 2 miles south of Rocky Flats. These 

parcels are located around Arvada Reservoir, along Leyden Gulch, and in the area between the 

RESOURCE INVENTORY 39
two. A network of paved and unpaved trails run throughout the City of Arvada, including the 

unpaved Leyden Gulch trail located about 1.5 miles south of Rocky Flats. 

City of Westminster Open Space 

The City of Westminster has several open space properties to the east and southeast of Rocky 

Flats. These properties include the Colorado Hills Open Space and Standley Lake Regional Park. 

Colorado Hills includes a soft-surface trail between Mower Reservoir and adjacent residential 

areas. Standley Lake is a regional destination for boating, swimming and picnicking. This park 

is also a focal point for Arvada and Westminster’s paved greenway trail systems. 

City and County of Broomfield Open Space 

Directly east of Rocky Flats, Broomfield owns the Great Western Open Space lands surrounding 

its Great Western Reservoir. This area consists mainly of former grazed or cultivated fields. The 

City and County of Broomfield considers Great Western Open Space to be a highly suitable 

receiving site for prairie dog relocation. The establishment of a large prairie dog town at Great 

Western Reservoir Open Space would likely attract a greater number of raptors and other 

predators to the area, and may encourage the expansion of prairie dogs in the eastern portions of 

the Rocky Flats NWR (City and County of Broomfield 2001). 

Town of Superior Open Space 

Superior’s open space is located across Highway 128 at the northeast corner of Rocky Flats, on 

the east side of McCaslin Boulevard. A network of paved trails throughout Superior’s residential 

neighborhoods connects to the Rock Creek Trail, which continues to the northeast into 

Broomfield. 

Proposed Trails and Open Space Facilities 

City of Arvada 

The City of Arvada Trails Master Plan has identified several potential trail corridors in the Rocky

Flats area (Arvada 2001). The proposed Big Dry Creek Trail would follow the creek from

Standley Lake west toward Highway 93, directly abutting the Rocky Flats site at one location. 

On the south side of Highway 72, the proposed Barbara Gulch Trail would connect the City of

Arvada to the Highway 72/93 intersection. 

Denver Water 

A new off-channel water storage reservoir is proposed for the Leyden Reservoir site to the 

southwest of the Highway 93/72 intersection. If implemented, Denver Water land surrounding

the reservoir will be managed by the City of Arvada as open space (Bassett 2002). 

RESOURCE INVENTORY 40
Front Range Trail 

The Front Range Trail planning project identified a potential north/south trail corridor along the 

east side of Highway 93, between the highway and the Rocky Flats boundary. 

Town of Superior 

The Town of Superior Parks, Open Space and Trails Plan proposes a trail along the north side of 

Highway 128 and east of McCaslin Boulevard. This trail would be directly across the highway

from Rocky Flats’ northeast corner (Superior 2001). 

Coal Creek Canyon Park 

The Management Plan for Jefferson County Open Space’s Coal Creek Canyon Park describes the 

potential for soft-surface, multi-use trails on Jefferson County lands about 1 mile southwest of 

Rocky Flats. However, Jefferson County does not plan to develop any recreational facilities until 

uncertainties are resolved regarding neighboring land uses (JCOS 2001). 

Air Quality

Rocky Flats is located within the boundary of the Denver Metropolitan Area for air quality

planning purposes. For many years, the Denver metropolitan area has experienced carbon 

monoxide, ozone, and particulate matter air pollution as well as visibility problems. These 

conditions have recently improved, however, and the Denver area is now in attainment of all of 

EPA’s health-based standards for air quality (EPA 2002). Regulatory requirements may control 

the timing of certain natural resources management activities, such as prescribed burning, which 

requires a permit from the State. 

Air quality is monitored at five air monitoring stations operated by the Colorado Department of 

Public Health and Environment. Two of these stations are located just off-site at the northeast 

and southeast site boundary along Indiana Street, downwind of Rocky Flats. All criteria air 

pollutants are below state standards. It has not been determined whether the air monitoring 

stations will be removed following cleanup of the site. 

Socioeconomics 

Population and Demographics 

The population in Jefferson County grew from 438,430 in 1990 to 527,056 in 2000 (U.S. Census 

Bureau 2002), an average annual increase of about 1.8 percent. Jefferson County population is

RESOURCE INVENTORY 41
expected to increase about 0.75 percent annually from 2000 to 2015, while the state population is 

expected to increase by 1.7 percent annually (Colorado Department of Local Affairs 2002). 

Rocky Flats is located in Jefferson County’s North Plains Community Planning Area, which also 

includes portions of Westminster, Arvada, Golden, and unincorporated areas. Within this 

planning area, the population grew from 8,453 in 1990 to 10,194 in 2000, an average annual 

increase of about 2 percent (Jefferson County 2002). About 95 percent of the North Plains 

population consider themselves to be white (compared to 83 percent state wide), while about 5

percent consider themselves to be Hispanic or Latino in origin (Jefferson County 2002). 

Employment 

The average unemployment rate for Jefferson County in 2001 was 3 percent, while the state 

average was 3.72 percent (Colorado Department of Local Affairs 2002). In 2000, the services 

sector employed 79,317 workers while the retail trade sector employed 62,838, and the 

government sector employed 51,762 (Colorado Department of Local Affairs 2002). 

Income 

In 2000, per capita personal income was $36,442, a 5.6 percent annual increase since 1990. Total 

personal income in Jefferson County was $19.3 billion in 2000, up from about $9.4 billion in

1990, reflecting an average annual growth rate of about 7.5 percent (Bureau of Economic 

Analysis 2002). The largest sources of work related personal earnings, by industry were services 

(16.1 percent), government (8.3 percent), and manufacturing (7.9 percent). Retail trade 

accounted for about 3 percent of the total personal income in 2000. Transfer payments, 

dividends, interest and rent accounted for 22 percent of personal income in 2000 (Bureau of 

Economic Analysis 2002). 

References 

Advanced Sciences, Inc. 1991. Surface-Water and Ground-Water Rights Study in the Vicinity of 

the Rocky Flats Plan. Prepared for EG&G Rocky Flats, Inc. Lakewood, Colorado. 

Bassett, Marie. 2002. Denver Water Department. Personal Communication with Bill Mangle, 

ERO Resources, September 4, 2002. 

Brennan, Mark. 2003. Boulder County Parks and Open Space Department. Personal 

Communication with Ron Beane, ERO Resources, April 16, 2003. 

Bureau of Economic Analysis. 2002. Regional Accounts Data: Local Area Personal Income. 

http://www.bea.doc.gov/regional/reis/action.cfm. 

City of Arvada. 2001. City of Arvada Parks, Trails and Open Space Plan. Prepared by EDAW. 

City of Boulder. 1996. Open Space/Real Estate Department. City of Boulder Grassland 

Management: Black-Tailed Prairie Dog Habitat Conservation Plan.

RESOURCE INVENTORY 42
City and County of Broomfield. 2001. Final Draft Policies for Prairie Dog Conservation and 

Management. 

Clippinger, N.W. 1989. Habitat suitability index models: black tailed prairie dog. Biological 

Report 82 (10.156): 1-21. U.S. Fish and Wildlife Research and Development. Washington, 

D.C. 

Colorado Department of Local Affairs. 2002. Colorado Economic and Demographic 

Information System. http://www.dola.state.co.us/is/cedishom.htm. 

Colorado Department of Public Health and Environment. 2003. Contaminants Released to 

Surface Water from Rocky Flats. Technical Topic Papers: Rocky Flats Historical Public 

Exposures Studies. http://www.cdphe.state.co.us/rf/contamin.htm. 

Dames & Moore. 1991. Cultural Resources Class III Survey of the Department of Energy Rocky

Flats Plant, Northern Jefferson and Boulder Counties, Colorado. Prepared for EG&G Rocky

Flats. 

Department of Energy. 1997. Rocky Flats Cumulative Impacts Document. Rocky Flats Field 

Office, Rocky Flats Environmental Technology Site. Golden, Colorado. 

Department of Energy – National Renewable Energy Laboratory. 2002. Final Site-Wide 

Environmental Assessment of National Renewable Energy Laboratory’s National Wind 

Technology Center. 

Department of Energy Rocky Flats Environmental Technology Site and the U.S. Fish and 

Wildlife Service. 2001. Integrated Natural Resources Management Plan, Environmental 

Assessment, and Finding of No Significant Impacts for Rock Creek Reserve, 2001-Closure. 

U.S. Environmental Protection Agency. 2002. Region 8 – Air Program. 

http://www.epa.gov/region8/air/. September 6, 2002. 

ESCO Associates, Inc. 1994. Report of Findings: Ute Ladies’-Tresses and Colorado Butterfly 

Weed Surveys. Rocky Flats Buffer Zone. Jefferson County, Colorado. 

ESCO Associates, Inc. 2002. Draft Report of Findings: Five-year Study of the Ecology of 

Bluestem-dominated Grasslands of the Rocky Flats Area, 1996-2001. Jefferson and Boulder 

Counties, Colorado. 

Essington, K.D., S.M. Kettler, S.E. Simonson, C.A. Pague, J.S. Sanderson, P.M. Pineda, and A.R. 

Ellingson. 1996. Natural Heritage Resources of the Rocky Flats Environmental Technology 

Site and their Conservation. Phase II: The Buffer Zone. Colorado Natural Heritage Program, 

Fort Collins, Colorado. 

Jefferson County. 2002. The North Plains Community Demographic Profile. 

http://206.247.49.21/ext/dpt/public_works/planning/demographics/community/northplains/north-plains.htm. 

Jefferson County Open Space. 2001. Executive Summary: Coal Creek Canyon Park 

Management Plan.

Kaiser-Hill Ecology Group. 2002. GIS data showing the geographical extent of wildfires 

between 1993 and 2002. “master fire file.shp.” 

Kaiser-Hill, LLC. 1997. Metadata report accompanying veg96b.shp GIS data showing land 

cover data derived from 1995-1996 field surveys. 

Kaiser-Hill, LLC. 2000. 1999 Annual Wildlife Survey for the Rocky Flats Environmental 

Technology Site. Golden, CO. 

RESOURCE INVENTORY 43
RESOURCE INVENTORY 44

Kaiser-Hill, LLC. 2001. 2000 Annual Wildlife Survey for the Rocky Flats Environmental 

Technology Site. Golden, CO. 

Kaiser-Hill, LLC. 2002a. 2002 Annual Vegetation Management Plan for the Rocky Flats 

Environmental Technology Site. Golden, CO. 

Kaiser-Hill, LLC. 2002b. Site-Wide Water Balance Model Report for the Rocky Flats 

Environmental Technology Site. 

Mount, Carl. 2003. Senior Environmental Protection Specialist. Colorado Division of Minerals 

and Geology. Personal communication with Bill Mangle, ERO Resources. April 21, 2003. 

Nelson, Jody. 2003. Senior Ecologist, Kaiser-Hill Ecology Group. Rocky Flats Environmental 

Technology Site. Personal communication with Bill Mangle, ERO Resources. January 14, 

2003. 

PTI Environmental Services. 1997a. Ecological Resource Management Plan for the Rocky Flats 

Environmental Technology Site. Prepared for Kaiser-Hill, LLC. 

PTI Environmental Services. 1997b. Tall Upland Shrubland at the Rocky Flats Environmental 

Technology Site. Prepared for Kaiser-Hill, LLC. 

Rocky Flats National Wildlife Refuge Act of 2001. 2001. Federal Register 115 Stat. 1379. 

Public Law 107-107-December 28, 2001. 

Shroba, Ralph R. and Carrara, P.E. 1996. Surficial Geologic Map of the Rocky Flats 

Environmental Technology Site and Vicinity, Jefferson and Boulder Counties, Colorado. U.S. 

Geological Survey. Map number OF-94-162. 

Superior (Town of). 2001. Town of Superior Parks, Open Space and Trails Plan. 

U.S. Census Bureau. 2002. American Factfinder Census Data. http://factfinder.census.gov. 

U.S. Fish and Wildlife Service. 2002a. Proposed Rule: Designation of Critical Habitat for the 

Preble's Meadow Jumping Mouse (Zapus hudsonius preblei); Federal Register, 65: 47153-

47210, July 17. 

U.S. Fish and Wildlife Service. 2002b. Candidate Conservation Program. 

http://endangered.fws.gov/candidates/index.html. 
Rocky Flats National Wildlife Refuge

Comprehensive Conservation Plan

Building 121

Commerce City, CO 80022 

303/289 0980

rockyflats@fws.gov

http://rockyflats.fws.gov

U.S. Fish and Wildlife Service

http://www.fws.gov

http://www.r6.fws.gov/larp

For Refuge Information

1 800/344 WILD

April 2003

Front Cover:

Preble’s Meadow

Jumping Mouse