Managing Toxic Algae at Hebgen Lake

Transcription

1 Managing Toxic Algae at Hebgen Lake

2 Outline Today s Presentation Hebgen Lake Background and Setting Monitoring Plan Action Plans Additional Measures

3 Blue-green Algal Blooms in Montana Canyon Ferry Reservoir (Broadwater & L&C Co.) Clark Canyon Reservoir (Beaverhead Co.) Cooney Reservoir (Carbon Co.) Harrison Lake (Madison Co.) Hebgen Lake Reservoir (Gallatin Co.) Homestake Lake (Jefferson Co.) Hyalite Reservoir (Gallatin Co.) Lake Mary Ronan (Lake Co.) Schoolmarm Lake (Ravalli Co.)

4 Hebgen Lake 13,000-acre Madison River Impoundment Heavy summer recreation use NorthWestern Energy Dam at outlet controls depth

5 NWE Dam The Narrows: few hundred ft wide Grayling Arm: fed by small streams, water chemistry major ions are calcium and bicarbonate, avg depth of 15 feet Madison Arm: fed by Madison River from Yellowstone Park, water chemistry major ions are sodium and bicarbonate

6 Historic Toxic Blooms at Hebgen Lake 1977, 1985, 1986, 1987, 1988 Livestock and pet deaths occurred Recreational activities were restricted by the local Board of Health Anabaena flos-aquae found to be dominant species in blooms and was implicated as toxin source through lab work with mice. Mice died in as little as 3 minutes. Other algal blooms were noted in the past, but not found to develop toxicity.

7 7

8 What do we do about it? 2000 FERC License required NWE to work with DEQ, USFS and GCCHD to develop a Toxic Algae Monitoring Plan Plan (2004) designed to monitor and evaluate composition and toxicity of algal blooms in Hebgen Reservoir and transmit the info to the proper local/state agencies for appropriate response. Plan Consists of: Monitoring Plan Stage 1 Action Plan: Information Stage 2 Action Plan: Warning Stage 3 Action Plan: Closure

9 BUOY Starting in 2010, PPL/NWE deployed an algaebot to remotely collect algae and Water Quality data

10 2014 Grayling Arm Cells/ml 24hr Moving Average and Water Temp The 24 hour moving average is plotted at the end of the 24 hr period. Values equal to were removed from the moving average calculation. The sensor measures phycocyanin (PCA) pigment which is specific for cyanobacteria /5 6/25 7/15 8/4 8/24 Date 24 hr MA Water Temperature 9/13 10/3 10/23 Temperature C PCA cells/ml Monitoring period: 6/06/14-10/23/14

11 Weekly Monitoring Rounds Starting in 2010, PPL/NWE hired a monitoring staff Completed weekly rounds to multiple locations May 20 August 31(extended if needed) Visual observations of algae growth Photo document each location Measures water temperature Collects algae sample for ID when present Collects water sample for toxicity test when warranted.

12 Trip Route

13 If floating mats of turquoise algae are observed, samples are sent to NWE to determine if toxin producers dominate

14 If sample is dominated by known toxin producer, water sample will be collected and shipped to lab for Ceriodaphnia bioassay and agencies notified. Bioassay results reported to agencies within 4 days. Positive bioassay requires confirmation sample to be taken.

15 Stage 1: Informational Outreach Toxic algae information letter sent to Hebgen Lake area landowners and Forest Service leasees Toxic algae information (public notice) signs are posted at numerous locations around the lake

16 Signs

17 Signs

18 Stage 2: Warning Initiated if bioassay is found to positive for toxin Warning signs are posted at all locations around the lake Public announcements made via radio and/or newspaper

19 WARNING Due to the presence of a toxic algal bloom, the Gallatin City-County Health Department recommends that people not swim in Hebgen Lake and that pets and livestock be kept from entering the lake or from drinking lake water. An algal bloom, consisting of many different kinds of blue-green algae, is occurring in Hebgen Lake. Tests have identified that some of the algae are producing toxins, which pose a threat to pets, livestock and people. To be safe, it is recommended to keep pets and livestock from entering the lake or drinking lake water. It is also recommended that no swimming occur in the lake at this time. Ingestion or prolonged contact with the algal bloom may result in illness, with signs such as muscle weakness, vomiting, diarrhea and/or nausea. If a pet has recently (within several hours) ingested lake water and is showing signs such as vomiting, lethargy, or disorientation, it should be taken to a veterinarian immediately. For more information, call the Gallatin City-County Health Department at (406)

20 Stage 3: Closure If Gallatin City-County Health Department (GCCHD) decides closure is necessary, they will notify NWE, USFS, DEQ Closure signs will be posted at all appropriate locations of closure GCCHD will notify newspapers, radio, and/or other media of closures

21 Additional Measures Additional measures Remote Sensing (satellite imagery analysis/interpretation) Abraxis Microcystin field test strips Microcystin and Saxitoxin Analysis Nutrient sampling Follow-up with ID on Henry s Lake 2015 Health Advisory 21

22 Questions???

23 Andy Welch Hydro Compliance Professional 1315 North Last Chance Gulch Helena, MT Office: (406) I Cell: (406) Andrew.Welch@northwestern.com 23

24 Who We Are Part II Total Assets: Total Capitalization: Total Capital Expenditures: Total Employees: 24 $3.2 billion $2.1 billion $322 million 1,430

25 Who We Are Part I Who we are 673,200 Customers 403,600 electric 269,600 natural gas Total owned generation MT 412 MW regulated (includes 150 MW (regulation services)) SD 376 MW (baseload) regulated Approximately 123,000 square miles of service territory in Montana, South Dakota and Nebraska 25