Third-Party Nutrient TMDL Review and Revision for the Truckee River, Nevada

A nutrient TMDL was developed for the Truckee River in 1994 to protect aquatic life uses by controlling algal growth and improving dissolved oxygen. The Cities of Reno and Sparks, Washoe County, and the Truckee Meadows Water Authority (TMWA) have initiated a thirdparty review and potential revision to the TMDL. Driving factors for the TMDL revision include likely implementation of improved river flow management, the need to address challenges in balancing regional growth with environmental health and economic impacts, availability of more appropriate science-backed data and modeling tools, and opportunities for a more flexible TMDL solution. The original focus of the nutrient TMDL included addressing solely the chemical relationships between nutrients and dissolved oxygen. A proposed addition for analysis is a physical and biological look at the conditions of the watershed. The revised Truckee River TMDL may provide unique opportunities for flexible, water quality improvement solutions including waste load modifications for the Cities of Reno and Sparks which would allow for less costly wastewater plant operations and support for planned growth. It is intended that the revised TMDL will be structured to allow trading of allocations between point and nonpoint sources as long as nonpoint reductions can be demonstrated and the total assimilative river capacity is not exceeded. The TMDL will also be designed to consider potential increases in assimilative capacity from geomorphic improvements such as channel modification from stream restoration or increased instream flows. The effort has experienced many challenges including lack of momentum, competing issues in the watershed, and recognition that revision of water quality standards must be considered. However there have also been numerous successes to date including collaboration with and support from regulators to consider site-specific changes to water quality standards, and a revision to the TMDL using a flexible and creative approach. There has also been increased collaboration among the stakeholders who often had been in adversarial positions related to water resources. There is a joint vision that expansion of the TMDL to a future, broader stakeholder-based process will likely provide multiple benefits for regional water quality management.