Protecting Public Health and the Environment.

Owyhee River (Middle) Subbasin

Subbasin at a Glance

Hydrologic Unit Code 17050107
Size 290 square miles (185,816 acres)

Water Bodies with EPA-Approved TMDLs (Category 4a)

Cabin and Corral Creeks and tributaries, Juniper Creek and tributaries, Middle Fork Owyhee River and tributaries, Noon Creek watershed, North Fork Owyhee River, Pleasant Valley Creek and tributaries

Beneficial Uses Affected Salmonid spawning, cold water aquatic life
Major Land Uses Grazing, agriculture
Date Approved by EPA February 2000
EPA Approval Letter
Date Addendum Approved by EPA July 2012
EPA Approval Letter

Subbasin Characteristics

The North and Middle Fork Owyhee River drainages are located within one 4th-order hydrologic unit in southwest Idaho. They generally drain west from Idaho into Oregon. The existing uses of tributaries of the North and Middle Forks Owyhee River include cold water biota, salmonid spawning, rearing of redband trout, secondary contact recreation, and agricultural water supply. Existing uses of the North and Middle Forks Owyhee River include those uses as well as primary contact recreation, domestic water supply, and special resource waters. Of these uses, only cold water biota, salmonid spawning, and salmonid rearing were affected by pollutants.

2000 Subbasin Assessment and TMDL

Stream temperature data from water bodies within the subbasin show many of the streams' temperatures exceed the Idaho and Oregon water quality temperature standards.

Some stream segments were also listed for sediment, bacteria, and/or flow alteration. A review of the biological and chemical sediment data available showed no violations of applicable water quality standards for sediment and no impairment to the biological community from sediment. Therefore, TMDLs for sediment were not written; however, there can be no increase to the current sediment loads.

Bacteria was listed as a pollutant of concern for the North Fork Owyhee River. However, sampling indicated bacteria levels did not violate current Idaho or Oregon standards, so a TMDL for bacteria was not written for the North Fork Owyhee River. Flow alteration was listed as a concern for several water bodies, but TMDLs were not prepared for flow alteration. Flow alteration is considered "pollution," not a "pollutant," and TMDLs are not required for water bodies impaired by pollution but not by specific pollutants. A TMDL is only required when a pollutant can be identified and in some way quantified.

2000 TMDL: Streams and Pollutants for Which TMDLs Were Developed

Middle Fork Owyhee River
Temperature
North Fork Owyhee River
Temperature
Big Spring Creek
Temperature
Cabin Creek
Temperature
Corral Creek
Temperature
Juniper Creek (two segments)
Temperature
Noon Creek
Temperature
Pleasant Valley Creek
Temperature
Squaw Creek (two segments)
Temperature

2012 Addendum

This document addresses the temperature impairments of 36 assessment units in the Owyhee River watershed in southwest Idaho. The Owyhee River watershed incorporates the Upper, South, and Middle Fork Owyhee River subbasins.

Temperature TMDLs were previously written for many assessment units in the Owyhee River watershed. However, the Idaho Department of Environmental Quality (DEQ) recommended rewriting those TMDLs using more appropriate shade targets based on knowledge of local vegetation types and natural stream widths. This document revises 25 previous TMDLs and establishes 11 new TMDLs.

 Subbasin  Hydrologic Unit Code (HUC)  Assessment Units with New TMDLs  Assessment Units with Updated TMDLs
Upper Owyhee River  17050104  11  10
South Fork Owyhee River  17050105  0  2
North and Middle Fork Owyhee River  17050107  0  13

2012 Addendum: Assessment Units and Pollutants for Which TMDLs Were Developed

Upper Owyhee River Subbasin

Description Assessment Unit Pollutant
Battle Creek upstream of Antelope Flat ID17050104SW023_02 Temperature
Battle Creek between Antelope Flat and Big Springs Creek ID17050104SW023_03 Temperature
Battle Creek between Big Springs Creek and Owyhee River ID17050104SW023_04 Temperature
Deep Creek between Hurry Back and Nickel Creeks ID17050104SW026_04 Temperature (updated)
Deep Creek between Nickel Creek and Owyhee River ID17050104SW026_05 Temperature (updated)
Pole Creek upstream of Mud Flat ID17050104SW028_02 Temperature (updated)
Pole Creek between Camas Creek and Mud Flat ID17050104SW028_03 Temperature (updated)
Pole Creek between Camas and Deep Creeks ID17050104SW028_04 Temperature (updated)
Camas Creek between Big Springs Butte and Pole Creek ID17050104SW029_03 Temperature
Camel Creek upstream of Sunshine Valley Creek ID17050104SW030_02 Temperature
Nickel, Smith, and Thomas Creek headwaters ID17050104SW031_02 Temperature
Nickel, Smith and Thomas Creeks—3rd order ID17050104SW031_03 Temperature
Nickel and Smith Creeks—4th order ID17050104SW031_04 Temperature
Castle Creek upstream of Skunk Creek ID17050104SW032_02 Temperature (updated)
Castle Creek between Skunk and Deep Creeks ID17050104SW032_03 Temperature (updated)
Beaver Creek upstream of Carter Creek ID17050104SW033_02 Temperature
Beaver Creek between Carter and Trap Creeks ID17050104SW033_03 Temperature
Beaver Creek between Trap and Deep Creeks ID17050104SW033_04 Temperature
West Fork Red Canyon ID17050104SW034_02 Temperature (updated)
East Fork Red Canyon and Red Canyon upstream of Petes Creek ID17050104SW034_03 Temperature (updated)
Red Canyon between Petes Creek and Owyhee River ID17050104SW034_04 Temperature (updated)

 

South Fork Owyhee River Subbasin

Description Assessment Unit Pollutant
South Fork Owyhee River upstream of Little Owyhee River ID17050105SW001_06 Temperature (updated)
South Fork Owyhee River downstream of Little Owyhee River ID17050105SW001_07 Temperature (updated)

 

North and Middle Fork Owyhee River Subbasin

Description Assessment Unit Pollutant
Middle Fork Owyhee River upstream of Summit Springs Creek  ID17050107SW004_02 Temperature (updated)
Middle Fork Owyhee River downstream of Summit Springs Creek ID17050107SW004_03 Temperature (updated)
North Fork Owyhee River upstream of Big Springs Creek ID17050107SW008_02 Temperature (updated)
North Fork Owyhee River between Big Spring and Pleasant Valley Creeks ID17050107SW008_03 Temperature (updated)

North Fork Owyhee River between Pleasant Valley and Juniper Creeks, and

Juniper Creek between Cabin Creek and North Fork Owyhee River
ID17050107SW008_04 Temperature (updated)
North Fork Owyhee River downstream of Juniper Creek ID17050107SW008_05 Temperature (updated)
Pleasant Valley Creek upstream of East Fork Pleasant Valley Creek ID17050107SW009_02 Temperature (updated)
Pleasant Valley Creek between North Fork Owyhee River and East Fork Pleasant Valley Creek ID17050107SW009_03 Temperature (updated)
Noon Creek ID17050107SW010_02 Temperature (updated)
Cabin and Corral Creek headwaters ID17050107SW011_02 Temperature (updated)
Cabin and Corral Creeks—3rd order ID17050107SW011_03 Temperature (updated)
Juniper Creek upstream of Buck Creek ID17050107SW012_02 Temperature (updated)
Juniper Creek between Buck and Cabin Creeks ID17050107SW012_03 Temperature (updated)

Subbasin Documents


Staff Contacts

Senior Water Quality Analyst
Julia Achabal
DEQ Boise Regional Office
1445 N. Orchard St.
Boise, ID 83706
(208) 373-0550
julia.achabal@deq.idaho.gov

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