Transportation

Geography

Historical Background

Identified Hazards

Issues

Maps

Canyon County has eight incorporated communities, Caldwell (pop. 25,967), Greenleaf (862), Melba (439), Middleton (2,978), Nampa (51,867), Notus (458), Parma (1,771), and Wilder (1,462). The total population for the county in 2000 was 131,441. That is an increase of 46% since 1990.

Transportation

Geography

Land Area: 603 square miles.

Historical Background

Established March 7, 1891 with its county seat at Caldwell. Current sources attribute the name to the canyon of the Boise River near Caldwell. However, both John Rees and Vardis Fisher believed it was named for the Snake River canyon which forms a natural boundary for the county. The Hudson's Bay Company established Fort Boise in 1834 near what is now Parma, but abandoned it in 1855. Immigrants traveled through Canyon County on the Oregon Trail.

County Seat: Caldwell

Drought - 1987-1992

Event Summary:   7 year drought, from 1987-1992.    This period saw the worst water shortage since the 1977 drought.   In 1987, Idaho requested $5.8 million in Emergency Conservation Funds to aid drought-stricken farmers.   In 1988, in Oneida County the Deep Creek Reservoir was shut off half-way through irrigation season because the water level was so low it was filling the sprinkler system with mud and silt.   Throughout the drought, reservoirs were consistently below capacity, resulting in irrigation water ending earlier than normal, crops being plowed under or not planted at all, and recreational activities being curtailed.   The drought caused high water temperatures in rivers, and the lack of perennial grass growth caused livestock to be removed from public lands early, while wildlife starved in many wintering areas.  Conservation measures were instituted for residential and commercial use.  Wells used for residential and agricultural sectors ran dry, and a moratorium on new wells was instituted.   In 1992 alone, $500 million was lost in agricultural production.

County Summary: 7 year drought (1987-1992) saw the worst water shortage in the state since the 1977 drought.

The Idaho Statesman; Idaho State Journal; Idaho Press Tribune; Times-News; Spokesman

Pestilence - 1985

Event Summary:    Grasshopper infestation led to pesticide spraying on over 6 million acres of range; Ada, Elmore, Owyhee and Minidoka counties declared a disaster by USDA, state disaster declaration 6/18/85

County Summary: Grasshopper infestation

The Idaho Statesman 3/1/86

Flood - February 1982

Event Summary:    Flooding in western Idaho from ice jams and swollen rivers and creeks.

County Summary: Flooding from Willow Creek closed roads in Middleton and threatened the Middleton High School.

The Idaho Statesman, 2/17/82

Flood - January 17, 1971

Event Summary:      Heavy rain and snow over four days caused flooding in southwest Idaho.

County Summary: Homes throughout Caldwell, Pleasant Valley, and Kuna-Mora were evacuated because of rising floodwaters. 

The Idaho Statesman 1/18/71

Flood - 2/1-3/1963

Event Summary:     $4,685,000.00 - Heavy snowfall followed by heavy rain caused snowmelt, and combined with large ice jams in several rivers, led to severe flooding in the Clearwater, Boise, Payette, Weiser, Portneuf and Snake River drainages.  Ice jams and high water in the Clearwater River raised the Hwy 95 bridge a foot off of its pilings.  An federal disaster declaration was issued February 15, 1963, for eight Idaho counties due to flooding: Fremont, Madison, Blaine, Owyhee, Bannock, Caribou, Gooding, and Lincoln.  Statewide highway damage was est. at $800,000; damage to county roads est. at $700,000.

County Summary: Floodwaters from local creeks, including Mason Creek, destroyed the bridge near Sunny Slope and flooded streets in North Nampa.  Homedale schools were closed because of bridge washouts and Melba students were stranded at school because of road closures.

The Idaho Statesman Feb. 2, 3, 8, 1963

Flood - August 1, 1955

Event Summary:   New York Canal break flooded homes and farms, reduced irrigation water flow to Canyon County farms.

County Summary:A break in the New York Canal caused the water flow to be shut off while repairs were done, severely affecting Canyon County farmers because the canal supplies 85%  of their irrigation water.  Farmlands without water during the repair were the Melba, South Nampa, Lakeview and South Deer Flat areas.

The Idaho Statesman 8/2/55

Flood - April-June 1943

Event Summary:     $1,000,000.00 - Snowmelt combined with rain led to flooding along the  Boise and Payette River basins ranging from Boise, Eagle, Emmett, down to Notus.  Throughout the area, over 200 families were evacuated, 11 highway bridges across the Boise River were closed for five days or more.  Hwy 21 was closed for over a week because of washouts from flooding creeks, isolating Idaho City and Boise Basin communities.  Of the damage, over $649,000 was agricultural: over 10,000 acres were flooded.  This flood provided the final impetus to build Lucky Peak Dam.

County Summary: Flooding from the Boise River reached Parma and Notus.  Damage to this area was primarily agricultural, including loss of crops, livestock, and farm buildings and equipment.  Bridges across the Boise River were also damaged and/or closed.  Farmers had to move livestock, then reseed and relevel fields.  Flood damage also included extra travel by dairies and other rural farmers to reach an open  bridge, as all but three bridges in the valley were closed.

Stacy, Susan M.; The Idaho Statesman 4/20/43, 6/10/83; USACE "Flood Plain Information Boise, Idaho and Vicinity" and "Flood Damage Report: the Boise River Flood"

Flood - May 2, 1938

Event Summary:   Boise and Payette River floods.

County Summary:Increased runoff in Boise River led to flooding of hundreds of acres of agricultural land in Parma.

The Idaho Statesman, 5/2/38

Flood - April 25, 1936

Event Summary:    Boise River flood.  Rain and melting snow combined to cause the Boise River to flood with a peak discharge est. at 19,700 cfs, the sixth largest recorded flood.  2 deaths were reported caused by the flood.  Hundreds of acres of agricultural land in the valley was flooded along the river, through Eagle, Star, Linder and Parma.  Spring runoff also led to flooding along the Payette River and Soldier Creek.  After the flood, the legislature appropriated $10,000 to improve the river channel, modify the bridges, and clean out timber and debris from the river and its banks.

County Summary:Hundreds of acres of agricultural land along the Boise River was flooded.   WPA workers strengthened the Roswell and Island bridges; near Caldwell, farmers had to move livestock to higher ground.

Stacy, Susan M.; The Idaho Statesman, 4/21/36, 4/22/36, 4/26/36, 4/27/36, 5/2/38; USACE "Flood Plain Information Boise, Idaho and Vicinity" and "Flood Plain Information Payette, Idaho and Vicinity"

Earthquake - May 12, 1916

Event Summary:   Earthquake in SW Idaho, centered near Cascade.  This quake was felt from Anaconda, Montana, to Reno, Nevada, an area over 50,000 miles, and measured 6.1 on the Richter scale.

County Summary: An earthquake centered near Cascade shook Nampa nearly as violently as Boise, but was less noticeable at Caldwell.

Harpham, Lynda Koll; The Idaho Statesman 5/13/16; 1/31/84; Earthquake History of the United States

Flood - Indian Creek flood - March 4, 1910

Event Summary:  

County Summary: Heavy rains and thawing ice dams along Indian Creek caused a break in the New York Canal from heavy flows, flooding the creek.  Floodwaters over 3' deep spread over the business district of Caldwell, with the heaviest damage on Main, Arthur and Kimball Streets (and Seventh Avenue.  Every basement in the business district was flooded, and considerable damage was done to homes, sidewalks, streets and yards.  Damages to roads and bridges totaled over $20,000; Pioneer Irrigation District canals received $3,500 damage.

$125,000.00

Idaho Press Tribune 6/25/01; Idaho Press Tribune 9/16/83

Flood - May 14-June 17, 1896

Event Summary:   Boise and Payette River floods

County Summary: Floodwaters from the Boise River broke through the head gates and cut off access to and from Caldwell.

Stacy, Susan M.; USACE "Flood Plain Information Boise, Idaho and Vicinity"; The Idaho Statesman, April 21, 

Flood - March 16, 1894

Event Summary:      Dam break at Indian Creek

County Summary:Following heavy rainfall, the dam near the head of Indian Creek (near Orchard) broke; floodwaters reached Caldwell.  Cellars were flooded, businesses damaged, and foot bridges washed away.  Trains were stopped for several days while debris was cleared away. $8,000.00 

Idaho Press Tribune 6/25/01

Flood - December 1871

Event Summary:    Boise River flood

County Summary: Boise River broke through Canyon County Water Company headgate, flooded bottom lands from Star to Middleton to Parma

Stacy, Susan M.

Flood - July 4, 1862

Event Summary:   Boise River flood from extremely high runoff; believed to be one of the highest water years, possibly four times the amount of the 1943 flood (100,000 second feet or greater)

County Summary:Boise River flood of river bottoms near present-day Caldwell

Stacy, Susan M.; The Idaho Statesman, 6/10/83

Identified Hazards ( Most likely to occur & greatest impact)

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