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Water Quality

Water Quality

Avista recognizes the role that healthy lakes, reservoirs and rivers play in providing important fish and wildlife habitat, and safe recreation opportunities for the public. As part of the Federal Energy Regulatory Commission's (FERC) Spokane River Project License, we have several ongoing water quality mitigation measures associated with our Spokane River operations in both Idaho and Washington, and we monitor several water quality parameters, such as total dissolved gas, temperature, and dissolved oxygen.

Total Dissolved Gases

Since 2010, Avista has been monitoring total dissolved gas (TDG) supersaturation in the forebays and tailraces at its Post Falls and Long Lake dams. To address TDG, we are looking into operational changes at the Post Falls Dam to reduce TDG levels and are currently investigating several different spillway modifications that may reduce TDG at Long Lake Dam.

Dissolved Oxygen

Avista is a participant in the Washington Department of Ecology’s Dissolved Oxygen Total Maximum Daily Load (DO TMDL) for the Spokane River and Lake Spokane (the reservoir created by Long Lake Dam). The DO TMDL is a water quality improvement plan that limits the combined amount of nutrients (i.e. phosphorus, organic matter, and ammonia) that can be discharged into the Spokane River from both point sources and non-point sources.  As required by the FERC License and the DO TMDL, Avista developed a Lake Spokane Dissolved Oxygen Water Quality Attainment Plan (DO WQAP), which identifies potential reasonable and feasible measures to reduce phosphorus from non-point source loading around the lake. Avista's goal is to improve dissolved oxygen concentrations when Lake Spokane does not meet the state’s standard.

Stratification of Lake Spokane during the summer also impacts dissolved oxygen levels in the river immediately downstream of Long Lake Dam. In an effort to address this, we investigated methods to increase the levels of dissolved oxygen when the turbines are operating during the late summer months. In 2010, we field tested draft tube aeration equipment at Long Lake Dam in an effort to add oxygen to river below the dam. The results from the field test indicated dissolved oxygen concentrations met the state’s standard when water passes through the turbines. As a result, Avista plans to continue with the draft tube aeration and monitor the dissolved oxygen improvements each summer during low flows through 2016. The results of this monitoring are posted to the Water Quality Plans & Reports section below.

Avista also provides funding to the Idaho Department of Environmental Quality (IDEQ) and the Coeur d’Alene Tribe to complete water quality monitoring in Coeur d’Alene Lake. The water quality monitoring is completed in accordance with the quality assurance protocol established in the Coeur d’Alene Lake Management Plan, which was developed jointly by the Coeur d’Alene Tribe and IDEQ. Avista also provides funding to IDEQ for the Citizen Volunteer Monitoring Program to complete water quality monitoring at select locations on the Spokane River, upstream of the Post Falls Dam.

The water quality monitoring being completed in Coeur d’Alene Lake and in the Spokane River, upstream of Post Falls Dam, will aid IDEQ and the Coeur d’Alene Tribe in assessing water quality related to dissolved oxygen and associated nutrients. The results of this monitoring are posted to the Water Quality Plans and Reports section below.

Temperature

Avista completed a Long Lake HED Temperature Water Quality Attainment Plan (Temperature WQAP), which evaluated temperature impairments in Lake Spokane, as well as the river immediately below Long Lake Dam.

With regard to the the river immediately below Long Lake Dam, the depth of the powerhouse intakes, which are about 30 feet below the lake’s surface, results in cooler water being discharged downstream from the dam, as compared with Lake Spokane’s surface temperatures during the heat of the summer. The temperatures immediately below the dam consistently meet Washington’s temperature criteria. Farther downstream, Avista also works with the Spokane Tribe to implement and monitor improvements in water temperature in tribal waters.

Bathymetry map links:

Lake Spokane (12 sheets total, including Sheet Index, with Ortho as basemap):

Sheet Index

Sheet 1      Sheet 2      Sheet 3      Sheet 4      Sheet 5      Sheet 6      Sheet 7      Sheet 8      Sheet 9      Sheet 10      Sheet 11

Lake Spokane (12 sheets total, including Sheet Index, with LiDAR as basemap):

Sheet Index

Sheet 1      Sheet 2      Sheet 3      Sheet 4     Sheet 5      Sheet 6      Sheet 7      Sheet 8      Sheet 9      Sheet 10      Sheet 11

Nine Mile (11 sheets total, including Sheet Index, with Ortho as basemap):

Sheet Index     

Sheet 1     Sheet 2      Sheet 3     Sheet 4      Sheet 5     Sheet 6      Sheet 7     Sheet 8     Sheet 9     Sheet 10 

Nine Mile (11 sheets total, including Sheet Index, with LiDAR as basemap):

Sheet Index     

Sheet 1      Sheet 2      Sheet 3      Sheet 4      Sheet 5     Sheet 6      Sheet 7     Sheet 8     Sheet 9     Sheet 10

 

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Water Quality Work Plans and Reports

As part of the Spokane River Project License, Avista is implementing water quality mitigation measures in consultation with various regulators, agency partners, and stakeholders.

Work plans, analyses, monitoring plans, and annual monitoring/summary reports associated with the water quality mitigation measures identified in the License are posted, and available for download.  These include:

Total Dissolved Gases (TDG)

Long Lake HED

Long Lake Dam TDG Water Quality Attainment Plan, July 2010
Long Lake Dam TDG Gas Abatement Phase II Feasibility Study, August 2010
Long Lake Dam TDG Abatement Feasibility Phase III Physical Model Study, 2011 Interim Report
Long Lake Dam TDG Annual Monitoring Report (2011, 2012, 2013)

Nine Mile HED

Long Lake and Nine Mile Total Dissolved Gas Monitoring Plan, March 26, 2010
Nine Mile HED TDG 2011 Annual Monitoring Report, February 16, 2012  

Post Falls HED

Post Falls HED TDG Control and Mitigation Program, June 11, 2010
Post Falls HED TDG Annual Monitoring Report (2011, 2012)

Dissolved Oxygen (DO)

Long Lake HED Tailrace Waters

Phase II Long Lake HED DO Improvement Project Report, February 7, 2011
Long Lake HED Tailrace DO Annual Monitoring Report (2011, 2012,2013)
Long Lake HED Tailrace DO Monitoring Plan, April 8, 2010

Lake Spokane

Lake Spokane DO Water Quality Attainment Plan, October 8, 2012 
Lake Spokane DO Water Quality Attainment Plan Annual Report (2013)
Detailed Dissolved Oxygen Phase II Feasibility and Implementation Plan, June 14, 2010
Potential Reasonable and Feasible Improvements and/or Mitigation Measures for Dissolved Oxygen in Lake Spokane, December 28, 2009

Coeur d’Alene Lake  (non-Tribal waters)

Coeur d’Alene Lake 2010 Water Quality Monitoring Report (completed by IDEQ, in cooperation with Avista) (2010, 2011)

Coeur d’Alene Lake (Tribal waters)

Coeur d’Alene Reservation Water Quality Monitoring, Annual Summary Reports, 4(e) Condition No. 5 (2010, 2011)
Coeur d’Alene Reservation Water Quality Monitoring Plan, 4(e) Condition No. 5, June 18, 2010

Temperature

Long Lake HED

Long Lake Dam Reservoir and Tailrace Temperature Water Quality Attainment Plan, January 25, 2011
Long Lake HED Annual Temperature Monitoring Report (2011, 2012,2013)  

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Water Quality Correspondence

Communication and correspondence between Avista, its agency partners, regulators, and stakeholders is essential as Avista implements its water quality programs. The following FERC documents and agency correspondences are provided for your reference.

Total Dissolved Gases (TDG)

Long Lake HED

Ecology's Comments on 2011 Long Lake Dam TDG, March 21, 2012  
FERC Acknowledgement Letter regarding TDG, DO, and Temperature below Long Lake Dam, September 15, 2011
Ecology's Letter Commenting on 2011 Long Lake HED TDG Phase II Feasibility Study Final Report, April 11, 2011
Ecology Letter Approving 2010 TDG Monitoring Report, April 11, 2011
FERC Order Modifying and Approving Total Dissolved Gas Attainment and Monitoring Plans for the Long Lake Development, December 14, 2010

Nine Mile HED

Ecology's Response to Request for Comments on 2011 Nine Mile TDG Monitoring Report, March 21, 2012
Ecology Letter Approval of Delay in TDG Monitoring at Nine Mile HED, February 17, 2012
FERC Order Modifying and Approving TDG Monitoring Plan for the Nine Mile Development, issued December 14, 2010

Post Falls HED

IDEQ Approval Letter, Post Falls TDG Control and Mitigation Program, June 10, 2010

Dissolved Oxygen (DO)

Long Lake HED

FERC Letter/Reference to Avista's Submittal of 2012 Water Quality Monitoring and Study Reports, July 25, 2013 
FERC Acknowledgement Letter regarding TDG, DO, and Temperature below Long Lake Dam, September 15, 2011 

Lake Spokane

FERC Order Modifying and Approving Water Quality Attainment Plan, December 19, 2012
FERC Order Granting Extension of Time to file Water Quality Attainment Plan, August 23, 2012
Avista's Request for Extension of Time to file Water Quality Attainment Plan, August 8, 2012
Ecology Letter Regarding Potential Reasonable and Feasible Measures for Dissolved Oxygen in Lake Spokane, March 4, 2010
FERC Order Amending License to Include Revised Water Quality Certification and Requiring Dissolved Oxygen Water Quality Attainment Plan, Issued July 9, 2010

Coeur d’Alene Lake (Tribal Waters)

FERC Order Approving Water Quality Monitoring Plan Under Paragraph G, issued October 15, 2010
FERC, Errata Notice, Order Approving Water Quality Monitoring Plan Under Paragraph G, issued October 15, 2010
Department of Interior's Approval of Water Quality Monitoring, Wetland and Riparian Habitat, and Aquatic Weed Management Plans for the Spokane River Hydroelectric Project, FERC No. 2545, June 17, 2010

Temperature

FERC Order Amending Water Quality Monitoring and Quality Assurance Project Plan Pursuant to Article 401(A)(12), May 10, 2011
Ecology Letter Approving Long Lake HED Temperature Water Quality Attainment Plan, January 25, 2011

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Water Quality Contacts

The regulators, agency partners, and stakeholders that Avista works with and their website information is provided below:

Coeur d’Alene Tribe – http://www.cdatribe-nsn.gov/

Idaho Department of Environmental Quality – http://www.deq.idaho.gov/

Idaho Department of Fish and Game – http://fishandgame.idaho.gov/

Lake Spokane Association – http://www.lakespokaneassociation.org/index.htm

Spokane County Conservation District –  http://www.sccd.org/

Stevens County Conservation District – http://www.scc.wa.gov/

U.S. Department of Interior, Bureau of Indian Affairs – http://www.bia.gov/

U.S. Fish and Wildlife Service – http://www.fws.gov/

Washington Department of Ecology – http://www.ecy.wa.gov/programs/wq/links/plants.html

Washington Department of Fish and Wildlife – http://www.wdfw.wa.gov/

For more information about Avista’s Water Quality Management Programs, please contact:

Meghan Lunney
Aquatic Resource Specialist
Avista Utilities
1411 E. Mission Ave., MSC-1
Spokane, WA 99220-3727
Office: (509) 495-4643
meghan.lunney@avistacorp.com

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