| Data | Details |
|---|---|
| Hydrologic Unit Codes | 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
| Stream | Pollutants |
|---|---|
| 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) |
2008 Addemdum
This is an addendum to the Lower Boise River TMDL for sediment and bacteria approved by the US Environmental Protection Agency on January 25, 2000. The addendum provided the Avimor Development and the City of Kuna, Idaho, with wasteload allocations for total suspended solids and E. coli bacteria for a discharge to Dry Creek and Indian Creek, respectively. DEQ also outlines in this addendum the manner in which the sediment reserved for growth shall be allocated to new and existing sources in the future. The bolded changes in the addendum are made on pages 61, 62, 64, and 72 of the original document. Table 15 was revised in June 2012.
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 Creeks3rd 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 Document(s)
- This subbasin assessment and TMDL document is not available electronically. To view a hard copy, contact DEQ’s staff contact listed above.
- Implementation Plan for the North and Middle Fork of the Owyhee River (February 2002)
- North and Middle Fork Owyhee River TMDL Five-Year Review (June 2009)
- Owyhee River Watershed Total Maximum Daily Load Temperature Addendum: North and Middle Fork Owyhee, South Fork Owyhee, and Upper Owyhee (June 2012)
- Owyhee River Watershed TMDL Temperature Addendum: North and Middle Fork Owyhee, South Fork Owyhee, and Upper Owyhee Agriculture Implementation Plan (May 2017)
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