# Presentation: 344044

## Libby Dam June 2006 Spill:Total Dissolved Gas Monitoring

## Libby Dam June 2006 Spill

- Introduction
- Corps of Engineers project
- Spill occurred between June 8 – June 27, 2006
- Spillway discharge 1.5 to 31 kcfs
- Total project discharge 25.5 to 55 kcfs
- TDG monitoring vs. TDG exchange study
- Limited monitoring scope

## Libby Dam June 2006 Spill

- Project Site
-  Libby Dam
- Headwater project.
- Straight concrete gravity gate controlled dam, 370 feet high and 2,887 feet long, located at RM 221.9 on the Kootenai River.
- Built by the COE (1966-1972) for flood control.
- Selective withdrawal system used to maintain downstream temperatures.
- Full pool elevation 2459 ft, spillway crest 2405 ft.
- Lake Koocanusa
- Reservoir is approximately 90 miles long.
- Provides 4.98 million acre-feet of storage.
- Kootenai River

## Location of Libby Dam and Lake Koocanusa in the Kootenai River Basin.

## Libby Dam June 2006 Spill

- Study Design
- Real Time Monitoring
- Station LBQM at USGS tailwater gage
- Located 0.6 miles downstream on left bank to capture maximum TDG
- Automated Loggers
- Transect of 3 instruments at Thompson Bridge (Station TMPSN1-3), located immediately downstream of Libby Dam to measure lateral TDG distribution
- One instrument located 8.5 miles downstream at a constriction in the Kootenai River (Station HAUL) represents mixed river conditions
- One instrument located in back eddy of spill (Station SPW3)
- Parameters
- Total dissolved gas (TDG)
- Temperature
- Depth
- Operating Conditions
- Spill occurred between June 8 – June 27
- Spillway discharge 1.5 to 31 kcfs
- Total discharge 25.5 to 55 kcfs

## Libby Dam June 2006 Spill

- Sampling Period
-  Real Time Station
- Station LBQM operational June 8 to 27, 2006
- Automated Loggers
- Station TMPSN1-3 operational June 18 to 27, 2006
- Data from June 14 to June 18 were invalid due to insufficient sampler depth
- Station HAUL operational June 14 to 27, 2006
- Station SPW3 operational June 20 and 21, 2006

## TDG Sampling Stations in the Kootenai River Near Libby Dam

**HAUL**

**TMPSN**

**LBQM**

**SPW**

**Full Time Station**
**Part Time Station**

- 1 Mile

## SPW3

- TMPSN3

- TMPSN2

- TMPSN1

- LBQM

- TDG Sampling Stations in the Kootenai River Immediately Below Libby Dam

**Full Time Station**
**Part Time Station**

- 0.25 Mile

## TDG monitoring stations at Libby Dam tailwater

**TMPSN1**

**TMPSN2**

**TMPSN3**

**LBQM**

**SPW3**

## Libby Dam June 2006 Spill

## Water Quality Sampling Instruments
Real Time Station
Hydrolab MiniSonde 4a TDG sensor/Common Sensing barometer
Geomation Model 2380 DCP, Solar Power
Radio transmission station
Measurements collected every hour
Logger Stations
Hydrolab DataSonde 4 and MiniSonde 4a 
Automated wireless logging
Deployed on bottom of river
Measurements logged on 30-minute intervals
Calibration
COE data quality criteria
Pre and post deployment
Laboratory calibrations
Field calibrations

- Real Time Station
- Hydrolab MiniSonde 4a TDG sensor/Common Sensing barometer
- Geomation Model 2380 DCP, Solar Power
- Radio transmission station
- Measurements collected every hour
- Logger Stations
- Hydrolab DataSonde 4 and MiniSonde 4a
- Automated wireless logging
- Deployed on bottom of river
- Measurements logged on 30-minute intervals
- Calibration
- COE data quality criteria
- Pre and post deployment
- Laboratory calibrations
- Field calibrations

- Libby Dam June 2006 Spill

## Libby Dam June 2006 Spill

## Libby Dam June 2006 Spill

## Libby Dam June 2006 Spill

- Lateral and longitudinal TDG gradients were apparent in the Kootenai River at all spillway flows
- Maximum TDG saturations along the left channel bank
- Lowest TDG saturations associated with powerhouse flows along the right channel bank
- Mixing of powerhouse flows and riverine processes caused diminishing TDG saturations downstream
- Maximum TDG saturation at TMPSN1 (133%), at LBQM (131%), and at HAUL (120%)

## Libby Dam June 2006 Spill

- Spillway Releases Resulted in Elevated of TDG Pressures in Kootenai River
- TDG saturation at station TMPSN1 and LBQM were similar during 2006 spill
- Abrupt increase (107-123%) in TDG Pressure as a function of Spill 1.5-6 kcfs
- Little increase (123-125%) in TDG pressure as a function of spill 6-15 kcfs
- Mild Increase (124-133%) in TDG Pressure as a Function of Spill 15-31 kcfs
- TDG saturation at station LBQM was at or below the Montana standard of 110% at spillway releases less than 2 kcfs
- TDG saturation at station HAUL represented nearly well mixed conditions

## Libby Dam June 2006 Spill

**Observed total dissolved gas saturation versus total spillway discharge at Libby Dam, June 2006.**

## Observed and calculated stilling basin total dissolved gas saturation versus total spillway discharge at Libby Dam, summer 2002.

**Observed and calculated stilling basin total dissolved gas saturation versus total spillway discharge at Libby Dam, summer 2002.**

## Relationship between observed and calculated Station HAUL total dissolved gas saturation versus total spillway discharge at Libby Dam, June 2006.

- Libby Dam June 2006 Spill

## Libby Dam June 2006 Spill

- Fixed monitoring station at Libby Dam (LBQM) was representative of river conditions for TDG
- Strong lateral gradient in TDG saturations in the Kootenai River below Libby Dam at all spillway flows
- Maximum TDG saturations observed at Thompson Bridge (133%)
- Kootenai River nearly well mixed at station HAUL with a maximum TDG saturation of 120%