Protecting Public Health and the Environment.

Owyhee River (South Fork) Subbasin

Subbasin at a Glance

Hydrologic Unit Code 17050105
Size 1,850 square miles (1,183,923 acres) total
242 square miles (154,810 acres) in Idaho

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

South Fork Owyhee River
Beneficial Uses Affected Primary contact recreation, secondary contact recreation, cold water aquatic life, salmonid spawning, domestic water supply, agricultural water supply
Major Land Uses Livestock grazing
Date Approved by EPA March 2000
Approval Letter
Date Addendum Approved by EPA July 2012
Approval Letter

Subbasin Characteristics

The South Fork Owyhee River is located in the far southwestern portion of Idaho and originates in the north-central portion of Nevada. The area is predominately open desert and deep canyons.

The hydrology of the South Fork Owyhee River is the river itself. No perennial streams feed the river within Idaho. The South Fork Owyhee River is subject to “flashy” flow conditions with peak flows occurring anytime from January to June. There are no major impoundments in either Nevada or Idaho.

1999 Subbasin Assessment and TMDL

With the exception of temperature, water column chemistry meets Idaho water quality standards. Water temperatures often exceed water quality standards for the protection of both cold water biota and salmonid spawning. Warm water temperatures may be the most important factor limiting the presence of trout species. There is no indication that sediments are impairing beneficial uses.

A TMDL for temperature is an appropriate vehicle for addressing temperature concerns in the South Fork Owyhee River. A load capacity is assigned in this original TMDL, which includes a load allocation for the water as it enters the state of Idaho.

If the South Fork Owyhee River is able to meet Idaho temperature criteria at the Idaho/Nevada border, the argument could be made that the additional increase in Idaho is natural, and site-specific criteria could be developed. Alternatively, if the South Fork Owyhee River cannot meet Idaho temperature criteria at the border, then Idaho and Nevada will need to work together to develop appropriate site-specific criteria.

1999 TMDL: Stream and Pollutant for Which TMDLs Were Developed

South Fork Owyhee River
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

Water Quality Scientist
Danie Merriman
DEQ Boise Regional Office
1445 N. Orchard St.
Boise, ID 83706
(208) 373-0589
danie.merriman@deq.idaho.gov