The Ditch Project - 150 years of ditches: Boulder's Constructed Landscape

Natural History Timeline of the Boulder Valley

13000 BC

World population: approximately 4 million.
Humans arrive in North America.
North American mammoths, mastodons, camels, horses, stag-moose, and giant ground sloth become extinct within several thousand years.
American bison evolve from a larger native species.
No native earthworms are present on the plains, having been wiped out in the last Ice Age.

9500 BC to 1850AD

Humans move into the Boulder watershed.
Fire used for hunting, clearing land and warfare.
American bison population estimated to be 25 to 30 million.

500 BC

World population: 100 million

1492

Columbus sails the ocean blue.

1539

Coronado journeys up the Rio Grande to Colorado, releasing some of his horses to the wild.

1600s

Canada thistle introduced through farm seed to North America

1650

World population: half a billion.

1620

Pilgrims land at Plymouth Rock.

1680

Horses released to wild during the Pueblo Revolt in New Mexico.

1700s

Invasive weed teasel introduced to North America.

1776

Mastery of horses and guns allows native hunters to kill more bison, and leads to more conflict between tribes.
Escalante Expedition describes tamarisk growing along Southwestern rivers.

1793

First reports of cheat grass in U.S. Cheat grass was probably introduced to both East and West Coasts directly from Europe.

1804

World population: one billion

1820s

Otter and beaver trapping begins on the streams of the Rockies, ending beaver impoundments in riparian areas for decades.
Bison are extinct east of the Mississippi.

1823

Sewell Newhouse produces the #4 beaver trap, favorite of mountain men, in Oneida, N.Y.
Tamarisk imported to eastern U.S, as an ornamental landscape plant.

1830

First wagons brought up the Platte River and along the Oregon Trail.
Explorers and settlers heading west use most of the wood and grass along the Platte and Arkansas rivers.
Trails bring exotic weeds like dandelion, thistle and plantain to Colorado.
Grizzly bear is common on the plains.
Bald eagles, white pelicans, Canada geese and osprey are rarely seen along Platte.

1859

Gold discovered at Gold Run in Gold Hill.
Boulder City established.
Coal discovered in Marshall.
Trees along Front Range cut for lumber and fuel for mines and houses.
Miners dump mining and mill wastes in water. Hydraulic and placer mining alter stream channels, water turbidity and hillsides.
First irrigation ditches dug in Boulder County.

1860

Farmers “break” the plains with sod-buster plows to feed miners and new towns. Arapaho Indians conduct the “last great antelope hunt” in the Boulder Valley and the last big buffalo kill, near Red Rocks amphitheater.
Norway rat arrives in Denver.

1862

The Homestead Act grants 160 acres of free land to settlers, bringing many more farmers to Boulder.
Changing prairie to farmland decreases the numbers of mountain plover, lark bunting and long-billed curlew.

1863

Boulder’s first reservoir, Pancost Lake, is constructed at the site of what is now Leggett-Owens reservoir.

1864

Colonel Chivington, with Boulder’s Company "D" of the 3rd Colorado Volunteer Cavalry, massacres Arapaho and Cheyenne Indians at Sand Creek.

1869

Bounty on wolves enacted in Colorado.

1872

Brook trout cultivated in hatcheries in Colorado.

1873

Railroad extended to Boulder, opening the area to speculative cattle industry supplying the East.
Gregory Canyon road is used by ranchers on the Western Slope to drive cattle over the Continental Divide to Denver until 1890.
Canada thistle listed as noxious weed in Nebraska.

1874

Invention of barbed wire leads to the end of the Open Range.

1875

Crack willow growing in Nebraska.
Earthworms start arriving in Colorado, via imported plants and fish-bait.

1870s

Boulder flour mills, powered by ditches, grind wheat for locals and the East.

1884

1091 bison remain in North America.

1885

First Arbor Day celebrated in Colorado. CU students and faculty transplant cottonwoods from Boulder Creek to around Old Main.

1887

Boulder’s last irrigation ditch begins construction.
Ditches over-appropriate Boulder and South Boulder creeks.
Boulder's reservoir building era begins.
Reservoirs capture spring peak flows. Return flows to the Platte allow ditches to be developed farther east on the South Platte.
Greenback trout become rare, due to sediment, toxic mine tailings, over-harvesting, agricultural diversions and interbreeding with non-native trout.
Long-billed curlew populations begin sustained decline.

1890

Eugene Schieffelin deliberately releases eighty starlings in New York City.

1893

Bounty enacted in Colorado ($1 for coyotes, $10 for cougars and bears).
Last river otters reported of on South Platte.

1894

Boulder Creek floods the City in a "100- year flood" caused by rapidly melting snow pack combined with heavy spring rains.

1897

Cheat grass reported in eastern Colorado.

1898

Boulder secures 1,800 acres of mountain backdrop from South Boulder Creek to Sunshine Canyon.

1900's

North American bullfrog introduced to Colorado, perhaps through fish stocking programs.
Fox squirrel introduced to Colorado. Fox squirrels expand their range by following riparian corridors, invading urbanized areas, and inhabiting areas newly cultivated with deciduous trees.
Tamarisk planted for erosion control on the Colorado and Rio Grande rivers.
Bubonic plague enters the Western ecosystem from an outbreak in San Francisco.
Last mink reported in Boulder Creek.

1906

Russian olives promoted for planting in Colorado as wind-breaks and for highway beautification.
Construction begins on Barker Dam.
Last river otter in Colorado sighted on Yampa River.
Extermination of the wolf declared the paramount objective of the U.S. government. Beaver reported as common on Boulder creeks.
White- tailed deer found in thickets along Boulder Creek.

1908

Boulder Fish and Game Club starts stocking high mountain lakes with trout, and lower lakes with bass, bluegill, crappie and perch.

1910

Nationally, 5 million acres of forest burn and 78 people are killed in forest fires. Active suppression by U.S. Forest Service of all forest fires begins.

1919

First Colorado opossum found in Boulder at Green Mountain Cemetery. Irrigated agriculture and a warming climate allow expansion of opossum's range into Colorado.

1920s

Cheat grass infests entire West and considered the worst noxious weed.
Goose populations plummet nation wide from habitat loss and over-hunting.

1924

Asian freshwater clams brought to eastern U.S. by immigrants.

1927

World population: 2 billion.

1929

Arapaho Glacier is deeded to the City of Boulder.
$50 bounty offered on mountain lions in Colorado.

1933

Dust Bowl.
The Civilian Conservation Corps plants 538 million trees nation-wide.

1937

The Colorado-Big Thompson Project begins construction to bring Colorado River water to the northern Front Range.
Colorado Natural History Museum declares greenback trout extinct.

1938

Major storm causes extensive flood damage in Eldorado Springs along South Boulder Creek.

1939

Starlings are observed in Colorado.
DDT invented.

1943

Last wolf in Colorado is killed.
Plague reaches the Front Range of Colorado.
Russian olive is distributed widely for wind breaks in the West.

1945

Starlings arrive in Boulder County.

1954

Russian olive is naturalized along the South Platte River.
Gross Reservoir is completed.
Boulder Reservoir begins construction.
Raptor populations plummet due to egg-shell thinning from DDT ingestion.
Eastern blue jays start to expand range into Colorado, following new trees across the plains.

1955

United States Forest Service begins using converted aircraft to drop fire retardant.
Hunting decreases as suburbs spread out from Boulder. More whitetail and mule deer are found locally.

1957

A remnant group of greenback trout is discovered in upper Boulder Creek watershed.

1958

Whirling disease is found in the U.S.

1959

PLAN-Boulder is organized.
Less than 450 nesting pairs of bald eagles remain in the Continental U.S.
40 captured Canada geese are released in a Fort Collins lake and supplied with nesting boxes. These "live decoy" geese lure in migrating geese to Front Range lakes.

1960's

World population: 3 billion.
Construction of interstate highway system spreads teasel across U.S.
A small population of the giant Canada geese, thought to be extinct, is found in Minnesota.

1962

White pelicans begin nesting on reservoir islands in eastern Colorado.

1965

Bounty on mountain lions is removed.

1967

Boulder voters approve first Open Space purchases.

1970

CU students celebrate first Earth Day by painting out the large "CU" on the Third Flatiron.
Eastern blue jay and Steller's jay start to hybridize in Boulder.

1972

Use of DDT is phased out in the United States.
New U.S. Forest Service policy allows some wildfires to burn in designated wilderness areas.

1973

Endangered Species Act is signed into law.
Colorado In-stream Flow Protection Program begins.
Bald eagle, peregrine falcon, osprey, and greenback trout are listed as endangered by U.S. Fish & Wildlife Service.

1975

World population: 4 billion.
39 breeding pairs of peregrine falcons remain in U.S.

1976

Boulder voters approve a 2% growth limitation called the Danish Plan.
Big Thompson Flood kills 145 people.
River otter restoration begins in Colorado.

1977

Trout recovery plan restores greenback trout to the wild.

1978

Trans-basin diversions in Colorado total 634,760 acre-feet/year.
Bullfrog population explodes at Sawhill Ponds after possible introduction through fish stocking at the ponds.
Native northern leopard frog populations begin declining, perhaps due to predation, competition, or disease associated with bullfrogs.

1979

Last Colorado grizzly bear killed in San Juan Mountains.

1980s

Imported hatchery trout introduce whirling disease to Colorado.
200 non-native wintering bald eagles move into Boulder County to feast on introduced fish, waterfowl, road-kill deer, and prairie dogs.

1986

Boulder Open Space institutes nesting closures of the Flatirons to protect returning raptors.

1987

World population: five billion.

1990

City of Boulder dedicates a portion of its senior ditch rights to in-stream flows in Boulder Creek through town.

1992

Ute ladies' tresses orchids are listed as endangered.
Nesting peregrine falcons return to Boulder after 35-year absence.

1993

Whirling disease is found in Middle Park.
Freshwater clams evolve resistance to cold and spread to reservoirs around Denver.

1994

Peregrine falcon populations soar nation wide; species is de-listed.
Plague event wipes out most of the prairie dog colonies in Boulder.

1995

Boulder County Open Space begins prescribed burns.

1996

Colorado bans leg-hold and kill traps.
Beaver-human conflicts increase.
Tamarisk found at Sawhill Ponds and along Boulder Creek.

1998

Preble's meadow jumping mouse is listed as endangered.
Arapaho Glacier is downgraded to a "snowfield."
Discussion begins about de-listing greenback trout.
Non-native osprey move into Boulder County and nest at Valmont Lakes.
1 million+ acres of tamarisk cover the southwestern U.S.

1999

World population: six billion.
West Nile virus enters U.S. near New York City.

2001

Colorado lists Russian olive as noxious weed.

2002

West Nile virus reaches Boulder and decimates corvid (crows, magpies, ravens etc.) and other bird populations.
Bald eagles begin nesting along Boulder and St. Vrain creeks.
About 380,000 bison live in North America.

2003

Eurasian watermilfoil found in Boulder Creek, possibly from dumping a fish tank into Varsity Pond.

2004

Female wolf found dead at Idaho Springs.
New Zealand mud snails found in Boulder Creek below a trout farm.

2005

Second plague event wipes out many prairie dog colonies in Boulder.

2006

Mountain lion attacks boy on Flagstaff Mountain.
Starling population in U.S. estimated to be 140 million.
Curly leaf pondweed found at Boulder Reservoir.

2008

Whirling disease is present in 13 of 15 Colorado major drainages.
Coyotes attack Erie residents.
River otters spotted on South Platte and Poudre rivers.
12 pairs of osprey and 5 pairs of bald eagles nest in Boulder County.
Cheat grass covers 100 million acres of the West.
Zebra mussels are discovered in a reservoir in Pueblo.

2009

20,000 Canada geese live along the Front Range year-round.
240,000 giant Canada geese winter in Colorado annually.
Confirmed mink sighting on Boulder Creek.

2011

World population: 7 billion

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