TUALATIN VALLEY WATER DISTRICT BOARD OF COMMISSIONERS SW 170 th AVENUE BEAVERTON, OREGON WORK SESSION JUNE 1, :00 P.M.

Transcription

1 TUALATIN VALLEY WATER DISTRICT BOARD OF COMMISSIONERS 1850 SW 170 th AVENUE BEAVERTON, OREGON WORK SESSION JUNE 1, :00 P.M. Present: Commissioners: Jim Doane, Jim Duggan, Gordon Martin and Lisa Melyan (President Burke was absent) Staff Members: Greg DiLoreto, Patty Rupp, Gary Pippin, Bernice Bagnall, Todd Heidgerken, and Clark Balfour Others: Lisa Obermeyer and Kathryn Mallon of Montgomery Watson Harza, and Chris Uber and Brian Ginter of Murray Smith and Associates. Vice President Doane opened the Work Session at 6:07 p.m. for the purpose of Board discussion of reliability of three water sources, and water transmission line options from the Willamette Treatment Plant in Wilsonville to the Tualatin Valley Water District (TVWD). RELIABILITY OF THREE WATER SOURCES AVAILABLE TO TVWD General Manager DiLoreto gave the floor to Gary Pippin, Manager of Engineering Services who then introduced Lisa Obermeyer and Kathryn Mallon of the consulting firm of Montgomery Watson Harza. Ms. Mallon provided a PowerPoint Presentation and covered the reliability of the Willamette River and the Bull Run supply including the Columbia South Shore Well Field. Below is a summary of the highlights of the presentation. Willamette River Water Supply Statistics The cities of Corvallis and Wilsonville use the Willamette as a drinking water source 10 th largest river in the US 187 miles along main stem 12,0000 square mile drainage area 70% of watershed is forested 13 major tributaries 24 million acre-ft discharge annually Lowest recorded water level in USGS Gage is 52.5 feet Equivalent to 6,000 cfs or nearly 4,000 mgd River is considered 100% reliable for water quantity Page 1 of 1

2 Willamette River Water Quality Vulnerability Low probability of low impact risks Major catastrophic tanker truck spill (1 to 2 day event) Upstream Combined Sewer Overflow (1 day event) Willamette River Water Treatment Plant designed with multiple treatment barriers (graph) Portland Water Bureau Water Supply (PWB) Bull Run Supply: Columbia South Shore Wellfield: 65,000 acre watershed Dam 1 impounds 9.9 BG (billion gallons) Dam 2 impounds 6.8 BG 10.9 BG Useable Yield 28 wells along Columbia River near Airport 95 MGD capacity 12.4 BG yield PWB System Supply Reliability Assumptions 2025 demands from Regional Water Supply Plan (RWSP) TVWD: 42.3 mgd (Wolf Creek + Metzger) Conservation: Portland Retail: mgd TVWD: 2.09 mgd Others: 2 mgd Requires fish flows per Endangered Species Act (ESA) The demand line (182.3 mgd) at 1992 weather. Range during the peak seasons for 63 years is mgd. Portland Supply Reliability (6 month peak season May 1 to October 31) graph 1999 PWB System Vulnerability Study (EQE) Examine Risks of 38 Natural and Manmade Hazards: Highest Risks: Flooding in Sandy River (conduit failure at bridges) Turbidity in Bull Run Earthquakes (conduit failure at bridges) Wildfire in watershed Landslides (conduit failure) Summary of estimated storm impacts on turbidity in the Bull Run Supply (EQE 1999) graph Page 2 of 2

3 Ms. Mallon then gave the floor to Lisa Obermeyer, the consulting project manager for the Tualatin Basin Feasibility Study, who provided a PowerPoint presentation on the reliability of the Hagg Lake supply. Below are the highlights that Ms. Obermeyer covered. Hagg Lake Peak Season Demands vs. Storage Capacities (1 acre foot of water = 326,000 gallons) * Assuming Stimson dead storage same as Scoggins Storage Option Active Storage Capacity (TAF) Existing Scoggins Dam ft Scoggins Raise ft Scoggins Raise Stimson at 40-ft 122.6* Status of Water Supply Options from WS #2 (SCT Sain Creek Tunnel) (IXP Irrigation Exchange pipeline) Option Status Comment Scoggins 20-ft raise + SCT Dropped Insufficient Reliable Yield Stimson at 20-ft + SCT Dropped Insufficient Reliable Yield Scoggins 40 ft Raise Dropped Insufficient Reliable Yield Scoggins 40-ft Raise + SCT Retained Add RWP Pump Back Stimson at 40 ft. Dropped Insufficient Reliable Yield Stimson at 40 ft + SCT Dropped Add RWP Pump Back Scoggins 20-ft Raise + IXP Dropped Cost Prohibitive Scoggins 40-ft Raise + IXP Dropped Cost Prohibitive Raw Water Pump-Back Operations Assumptions Use Tualatin Valley Irrigation District (TVID) pumps max capacity 148 cfs Assume 100 cfs is available for 100 days, from November to early February to ensure filling at least to top of active conservation Operate pump-back when the reservoir would not otherwise fill Low end demands 40 ft. Scoggins Raise (graph) Low end demands, Stimson at 40-ft (graph) Partner Share Demands, 40 ft Scoggins Raise (graph) Summary of Reliable Alternatives New Yield CWS M & I Storage Option Sain Creek Tunnel RWP Pump- Back NPV ($/AF) Annual ($/AF) ft. Raise X 5, ft. Stimson X 6, ft. Raise X X 4, ft. Stimson X X 5, Page 3 of 3

4 Commissioner Doane commented that the material presentation contained the precise information that he was looking for and demonstrates the cost plus the reliability factor. He mentioned that although some sources may be less expensive than others, if reliability is a factor, it would not be the best choice for TVWD customers. Gary Pippin said that he would provide the draft report to the Commissioners by the end of the week. WATER TRANSMISSION LINE OPTIONS FROM THE WILLAMETTE RIVER TREATMENT PLANT TO TVWD Gary Pippin introduced Chris Uber, Vice President of Murray Smith and Associates who provided a PowerPoint presentation on the topic. He also displayed a map depicting water transmission line scenarios. Project Background: The preliminary engineering report was completed in Existing facilities include: Willamette River Water Treatment Plant Finished Water Transmission Main Treatment Plant to Wilsonville Road Kinsman Road Wilsonville Road to Barber Street Current Analysis Updated demand scenarios Updated participant connection points Updated alignment alternatives New Terminal Storage Updated project cost estimates Transmission System Criteria: Alignment Criteria 1998 preliminary engineering report alignments Regional planning corridors Existing Road Rights-of-Way (ROW) Bonneville Power Administration (BPA) ROW Portland General Electric (PGE) overhead power line easements Pipeline Criteria Steel Pipe Industry Standard Pipe Diameters Maximum Friction Loss = 1 foot per 1,000 feet of pipeline Supply from the Water Treatment Plant high service pump station Overflow Elevation of Terminal Storage = 465 feet Conceptual level cost estimates Page 4 of 4

5 Alignment Alternatives: Alignment Alternative A Easterly Alignment Parallels Washington County Supply Line (WCSL) through Tigard and Metzger area West through Beaverton to Dernbach reservoir site Alignment Alternative B Easterly alignment similar to alignment A Route through Tigard east of Bull Mountain Parallels WCSL north of Hwy 217 West through Beaverton to Dernbach site Alignment Alternative C Westerly alignment BPA ROW from Day Road to Beef Bend Road and Scholls Ferry to Dernbach reservoir site East through Beaverton to TVWD 54-inch diameter supply in Beaverton- Hillsdale Highway Alignment Alternative D Westerly alignment similar to alignment C West through Sherwood and north on Roy Rogers Road to Beef Bend Road and east to the BPA ROW BPA ROW north of Dernbach reservoir site East through Beaverton to TVWD 54-inch diameter supply in Beaverton- Hillsdale Highway Alignment Highlights Alignment Alternative A Difficult construction in Hall Blvd. Utility relocations ODOT permitting Traffic control Alternative B Difficult urban route through Tualatin and Tigard Crossing Hwy. 99W 2 crossings of Hwy. 217 Alternative C Stray current and corrosions concerns Wetland and groundwater issues between Wilsonville and Tualatin River Crossing of Hwy 99W and Hwy 217 Alternative D Stray current and corrosion concerns Difficult urban route through Sherwood on Tualatin Sherwood Road Crossing of Hwy 99W and Hwy 217 Additional Considerations Integrations of Existing Facilities Page 5 of 5

6 Tigard s 10 MG reservoir Washington County Supply Line system from Beaverton-Hillsdale Hwy and Oleson Rd. (South and West legs) Potential phasing opportunities Terminal storage alternatives Improvements to participant s distribution system Project Cost Summary Supply Scenario Transmission System Project Cost Summary (Total Project Cost = Millions of Dollars) Terminal Storage at Dernbach Site Additional $15-$30 Million project cost (20-40 MG Storage Pipe Diameter Range Alignment A Alignment B Alignment C Alignment D (Inches) Scenario $175 $185 $125 $140 Scenario $210 $220 $150 $160 Scenario $240 $260 $160 $175 Mr. Uber solicited questions and comments from the Board. The Board and staff discussed the information presented. Mr. Uber pointed out that material prices are climbing, and those factors have been included in the presentation. Commissioner Martin suggested that partners could play a roll in cost assumptions. Commissioner Melyan brought up the issue of possible stumbling blocks such as soil conditions, like those of the JWC pipeline project where boring was shut down due to petrified logs. A general discussion was held regarding negotiations for a wholesale contract with Portland. Commissioner Doane then opened the floor for public comment. PUBLIC COMMENT Tom Long 1695 SW Hicrest Avenue, Portland, OR 97225, representing Citizens For Safe Water (CFSW) Mr. Long indicated that although the recent testing of the Willamette River had come back favorable, he continues to feel uneasy in regard to new chemicals and mixing of chemicals in the Willamette that can t be detected, and the possible ill effects these chemicals could have on human life, especially children. He asked the Board if every source option had been explored over the years. Mr. Long suggested that the Board strongly consider conservation efforts in order to avoid using the Willamette as a future source. He said if he were faced with paying more for Bull Run water, he would. Mr. Long mentioned the recent studies of deformed fish in the Newberg Pool did not include thorough testing for chemicals. He indicated that the unknown is the biggest concern for CFSW. Mr. Long offered the services of Dr. Scott and CFSW to help with decision making of future sources. Page 6 of 6

7 Commissioner Doane and General Manager DiLoreto mentioned a regional study that was conducted by CH2M Hill in 1992 that identified six possible future sources. General Manager DiLoreto said he would obtain the report and provide copies for Mr. Long and the Board of Commissioners. The Work Session was adjourned at 7:55 p.m. BOARD OF COMMISSIONERS TUALATIN VALLEY WATER DISTRICT BY BY President, Richard Burke Lisa Melyan, Secretary Page 7 of 7