Tualatin Basin Water Supply Project

1
Tualatin Basin Water Supply Project
Water Quality, Wetlands and Wildlife Overview
August 2, 2006
2
Agenda

• Water Quality Review
• Scoggins Creek
• Tualatin Upper and Lower
• Wetlands Review
• Wildlife Review

3
TBWSP Alternatives

• Alternative 1 No Action
• Existing facilities in place
• Demand for Scoggins Barney water contract
  amounts
• Alternative 2 40-ft Dam Raise Option
• 40-ft Scoggins Dam Raise
• Raw Water Pipeline with Pumpback
• Alternative 3 Multiple Source Option
• 25-ft Scoggins Dam Raise
• Raw Water Pipeline with Pumpback
• Willamette River Water Treatment Plant Expansion

4
Tualatin River Currently Meets 2001 TP TMDL Goals
5
Primary WQ Issues for Scoggins Cr

• Designated salmonid spawning habitat and salmonid
  rearing and migration
• Temperature
• Scoggins Cr needs to meet WQ Criteria
• Dissolved Oxygen
• Scoggins Cr is required to have no measurable
  decreases in DO below natural conditions.

6
Modeling Methods

• USGS Hagg Lake Model Output
• USGS models of Upper and Lower Tualatin River
• USGS monitoring data (DO)

7
(No Transcript)
8
(No Transcript)
9
(No Transcript)
10
Primary WQ Issues for Upper and Lower Tualatin
River

• Temperature
• Dissolved Oxygen
• Ammonia (as it affects DO)
• Phosphorus (Algae in lower river)

11
(No Transcript)
12
(No Transcript)
13
Lower Tualatin River Dynamics

• Increase in flows from high quality source (Hagg
  Lake or AWTFs)
• Increases velocities
• Decreases travel time
• Decreases temperature overall (less opportunity
  for warming)
• Decreases opportunity for SOD to impact DO
• Decreases opportunity for algal growth
• Lower chlorophyll concentrations
• Overall balance in these interactions will be key

14
(No Transcript)
15
(No Transcript)
16
(No Transcript)
17
Overall Conclusions (preliminary)

• Scoggins Creek temperature regime improved (with
  multi-level outlet)
• Scoggins Creek DO improved (assuming reaeration
  at outlet is maintained)
• Upper mainstem temperature more natural
• Upper mainstem DO improved
• Flow augmentation needs to be managed to
  maintain/improve WQ as growth occurs
• Hagg Lake dam raise would not increase ammonia in
  Scoggins Cr or mainstem

18
Wetlands Impacts and Mitigation

• Alternative 2 40- foot dam raise
• Hagg Lake Area - 33.4 acres
• Raw Water Pipeline 20 acres (primarily Ag
  Lands)
• Alternative 3 25-foot dam raise
• Hagg Lake Area 27.4 acres
• Raw Water Pipeline 20 acres (primarily Ag
  lands)
• Willamette Transmission Pipeline 9 acres

19
Wetlands Maps Lake North Area
20
Wetlands Maps Lake Middle Area
21
Wetlands Maps Dam Area
22
Wetlands Mitigation Opportunities Below Dam
23
Wetlands Mitigation - Jackson Bottom
24
Mitigation needs (depending on ratios)

• On Site near Dam
• 20-27 acres
• Jackson Bottom
• 13 acres for Alt 2 (40)
• 7 acres for Alt 3 (25)
• CWS Design Process

25
Other Partnershipsand Mitigation Opportunities

• US Fish and Wildlife Wapato Lake Area
• Metro Lovejoy Property
• City of Hillsboro Hutchinson Property
• CWS Fernhill Area
• Stimson Mill Area

26
Wildlife and Wildlife Habitat Impacts and
Mitigation Opportunities

• Elk Meadow Habitat Mitigation areas
• Original areas - 139 acres
• Eagle Nest Sain Creek
• Other habitat areas

27
Wildlife and Wildlife Habitat Impacts and
Mitigation Opportunities

• Alternative 2 40- foot dam raise
• Hagg Lake Area - 347 acres forest lands
• Raw Water Pipeline primarily Ag Lands
• Alternative 3 25-foot dam raise
• Hagg Lake Area 235 acres
• Raw Water Pipeline primarily Ag lands
• Willamette Transmission Pipeline Ag/Urban area

28
Wildlife Habitat Impacts and Mitigation

• Alternative 2 40- foot dam raise
• Elk Meadow Mitigation 98.6 acres
• Within existing Park Boundary 58.6 acres
• City of Hillsboro Sain Creek Area 40 acres
• Alternative 3 25-foot dam raise
• Elk Meadow Mitigation 77.2 acres
• Within existing Park Boundary 58.6 acres
• City of Hillsboro Sain Creek Area 18.6 acres

29
(No Transcript)
30
Other Biological and TES elements

• Fish Habitat Elements
• Continued emphasis area
• TES Threatened, Endangered and Sensitive
  Species
• Bald Eagle, North Spotted Owl, Oregon Spotted
  Frog and several others.

31
Tualatin Basin Water Supply Project
Questions August 2, 2006