Total Maximum Daily Loads

The Upper Klamath and Lost River TMDL was first issued in May 2010. At that time the U.S. Environmental Protection Agency approved all of the components of the TMDL except for temperature. During this time it was also noted that seven entities affected by the TMDL in Klamath County petitioned the DEQ director to reconsider various components of the TMDL. The director granted the reconsideration based on these petitions.
DEQ responded to reconsideration petitions and released a draft modified TMDL for public review and comment in April 2017. Following this public review and comment period, DEQ issued the modified nutrient TMDL and submitted to EPA for approval in December 2017.

Current actions

DEQ issues revised Klamath and Lost River Total Maximum Daily Load

January 2019
DEQ issued the Upper Klamath and Lost River Subbasins TMDL and associated Water Quality Management Plan as orders in December 2017. The TMDL and WQMP address impairments of dissolved oxygen, ammonia, and chlorophyll-a. These impairments are addressed through wasteload allocations for the nutrients, phosphorus and nitrogen, and dissolved organic compounds.  
Following issuance, three entities petitioned the director for reconsideration of some very specific aspects of the TMDL. DEQ granted the reconsideration for two of the petitioners, which resulted in a delayed response from EPA in regards to the approval. The petitions that were accepted are from Langell Valley and Horsefly Irrigation Districts. The petitions mainly argued that the Irrigation Districts, referred to as Water Management Districts in the TMDL, do not meet the definition of a Designated Management Agency. Through internal discussion and consultation with the Department of Justice, the designation for the Water Management Districts was changed to Responsible Persons.
We worked through the process of completing the changes and on July 27, 2018 we opened a 14-day public comment period on the revised TMDL and WQMP. We received comments from Langell Valley and Horsefly Irrigation Districts, the Oregon Water Resources Commission, and PacifiCorp. We have prepared the response to comments document with the assistance of DOJ and we are now ready to issue the TMDL. 

Upper Klamath and Lost River Subbasins TMDL, 2017

Upper Klamath Order Memo

Upper Klamath Response to Comments

Upper Klamath Response to Petitions


TMDL issued by DEQ and submitted to EPA for approval on Dec. 21, 2010

Associated documents:

Memorandums of Agreement

​TMDL not started (minimal or no activity)


Klamath Basin Coordinator:
Mike Hiatt, Klamath Falls