Tualatin River Flow Management Technical Committee
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TUALATIN RIVER FLOW MANAGEMENT TECHNICAL COMMITTEE 2006 Annual Report prepared by Bernie Bonn for Photo Credits: Footbridge over Fanno Creek at Durham City Park Stewart Rounds, USGS Oregon Water Science Center TTTUALATINTUALATIN RIVER F FLOWLOW MANAGEMENT TECHNICAL COMMITTEE 2006 Annual Report Prepared by: Bernie Bonn For: Clean Water Services, Watershed Management Division In cooperation with: Oregon Water Resources Department, District 18 Watermaster FLOW MANAGEMENT TECHNICAL COMMITTEE MEMBERS From left to right: Charlie Harrison City of Beaverton Darrell Hedin, Secretary Oregon Water Resources Department Raj Kapur Clean Water Services Kevin Hanway Joint Water Commission Jan Miller, Chair Clean Water Services Wally Otto Tualatin Valley Irrigation District Mark Rosenkranz Lake Oswego Corporation Chris Wayland Washington County Parks — Hagg Lake Tom VanderPlaat Clean Water Services Randy Smith City of Forest Grove Not pictured: Niki Iverson Joint Water Commission ACRONYMS USED IN THIS REPORT FULL NAME ACRONYM FULL NAME ACRONYM Facilities Units of Measurement Springhill Pumping Plant SHPP Acre-Feet ac-ft Wastewater Treatment Plant WWTP Cubic Feet per Second cfs Organization Micrograms per liter µg/L Clean Water Services CWS Milligrams per Liter mg/L (formerly Unified Sewerage Agency) Million Gallons per Day MGD Joint Water Commission JWC Pounds lbs Lake Oswego Corporation LOC River Mile RM Oregon Department of Environmental Quality ODEQ Water Year WY Oregon Department of Transportation ODOT Other Oregon Water Resources Department OWRD Endangered Species Act ESA Tualatin Valley Irrigation District TVID Load Allocation LA Tualatin Valley Water District TVWD Total Maximum Daily Load TMDL U.S. Bureau of Reclamation BOR Wasteload Allocation WLA U.S. Geological Survey USGS Water Quality Parameters Dissolved Oxygen DO Sediment Oxygen Demand SOD Disclaimer This report and the data presented herein are provided without any warranty; explicit or implied. The data presented in this report were supplied by the members of the committee. Although every effort was made to faithfully reproduce the data as provided, the data are not warranted to be accurate, appropriate for interpretation, merchantable, or suitable for any particular purpose. TABLE OF CONTENTS 2006 Summary . 4 Background Basin Description and Tualatin River Basin Map . 5 Tualatin Basin Flow Management Technical Committee . 7 Member Reports for 2006 Reservoir Status . 8 Clean Water Services . 9 Hagg Lake Monitoring Program . 13 Joint Water Commission/Joint Barney Commission . 16 Lake Oswego Corporation. 18 Oregon Water Resources Department . 21 Tualatin Valley Irrigation District . 25 Water Quality Status Report . 29 Appendices A. Stream Gage Records—Data Tables and Hydrographs of Daily Data B. Selected Releases and Withdrawals—Data Tables and Hydrographs C. Scoggins Reservoir (Henry Hagg Lake) Operations—Monthly Data Reports D. Barney Reservoir Operations—Monthly Data Reports E. Municipal Water Use Allocations—Monthly Data F. Temperature Records—Data Tables and Graphs of Daily Data G. Hagg Lake—Monitoring Results for 2006 H. Precipitation Records— I. River Mile Indices— 2006 Tualatin River Flow Management Report 3 2006 SUMMARY This is the nineteenth year that the Tualatin River Flow Management Technical Committee has prepared an annual report documenting the flow management of the Tualatin River. Members of the committee include Clean Water Services (CWS), Tualatin Valley Irrigation District (TVID), Joint Water Commis- sion (JWC), Lake Oswego Corporation (LOC) and Oregon Water Resources Department (OWRD). Highlights for 2006 include: • The year was characterized by a warm spring and summer and early fall rains. Tualatin River at Farmington (RM 33.3 #14206500) 1989–2006 13000 1996 1989–1995, 1997–2000, 2002–2005 10000 2006 1000 Daily Mean Discharge (cfs) Discharge Mean Daily 2001 100 60 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1 9/1 1/1 10/1 11/1 12/1 Date • Both Barney and Scoggins Reservoirs filled. • Oregon Water Resources Division assumed the operation of the gaging station at Scoggins Creek below Henry Hagg Lake (#14202980) on October 1, 2006. Until then, the site was operated by the U.S. Geological Survey. 4 2006 Tualatin River Flow Managment Report BACKGROUND Basin Description The Tualatin River Basin comprises an area of 712 square miles situated in the northwest corner of Oregon and is a subbasin of the Willamette River. The headwaters are in the Coast Range and flow in a generally east- erly direction to the confluence with the Willamette River. The basin lies almost entirely in Washington County. (See map below) The Tualatin River is about 80 miles long and changes dramatically from its headwaters to its mouth. The mountain or headwater reach (upstream of RM 55) is narrow (about 15 ft) and steep with an average slope of about 74 ft/mi. The meander reach (RM 55–33) is wider with an average slope of about 1.3 ft/mi. The reser- voir reach (RM 33–3.4) is very wide (up to 150 ft) and has an estimated slope of only 0.08 ft/mi. It includes several deep pools. Travel times through this reach are very long. The slow movement of the water causes this reach to act much like a lake. In the riffle reach (RM 3.4–0), the Tualatin River flows through a short reservoir section and then drops into a narrow gorge near the City of West Linn before it enters the Willamette River just upstream of Willamette Falls. The average slope in this reach is 10 ft/mi. Tualatin River Basin 123°22'30'' 123°15' 123°00' 122°45' 122°37'30'' 26 WASHINGTON COLUMBIA 45°45' E a s W t e s t T U E A WASHINGTON G L C k A F e O N o r e T k r MULTNOMAH L F C I U A Gales o N M r k B R IA R IV M W E R O I L C North U r Banks L ee Plains N A TILLAMOOK k T M E A T OREGON y I T a N E K S D c 5 a M T ir y ek S re C k C re e A ek e n S r so c C on k O o Cornelius Hillsboro r e g B re g Forest C C RM k in c ill s Grove o Bea 50 R ve r M Henry rt a 26 on ed 45°30' Hagg Dilley C R ternut Cr Creek Lake UALATIN IVER ut T B Beaverton RM R I RM C RM Creek 40 V 60 E 70 Cherry H F a R ense n Grove E ris t n C Farmington Ch ree n H k o C A k RM Tigard r ee e Lake Ba L r 30 ek si E rris C Oswego n Bu RM bou M Scholls nda Creek 20 RM ry o 10 g M M l cF e ee a O w n Cr s a U B Tualatin O C N a r YAMHILL k rg C n e T e Nyb 205 o r A t k C e I a re N r S e C H n Sherwood West e Linn Portland k ic Study C h RM area 0 OREGON CLACKAMAS N T 0 510 MILESI T A E T R N 0 5 10 KILOMETERS R U A O P 5 M 45°15' Base modified from U.S. Geological Survey 1:100,000 topographic quadrangles, 1978–84 Designated urban growth area from Metro, 1998 RM River mile 10 2006 Tualatin River Flow Management Report 5 Water sources to the Tualatin River Precipitation: Seasonal rainfall accounts for most of the flow in the Tualatin Basin; stream flow from snowmelt is minimal. The amount of rainfall ranges from 110 inches on the eastern slopes of the Coast Range to 37 inches in the southeastern area of the drainage basin. Peak months for rainfall are November through February while the driest months are normally June through October. The peak streamflow month is usually February, and the lowest streamflow month is August. Barney Reservoir: Barney Reservoir is located on the Middle Fork of the North Fork of the Trask River. It has a capacity 20,000 acre-feet and stores water for Clean Water Services, the Tualatin Valley Water District, and the Cities of Beaverton, Hillsboro and Forest Grove. Water released from Barney Reservoir enters the Tualatin River at RM 78 via an aqueduct over a low Coast Range divide and via a pipeline. Water is released during the summer low-flow season to supplement shortages in natural flow. Scoggins Reservoir: Scoggins Creek enters the Tualatin River at RM 60.0. In the early 1970's the Bureau of Reclamation built an earthen dam on Scoggins Creek. Scoggins reservoir (Henry Hagg Lake) has an active storage capacity of 53,640 acre-feet. It is a multipurpose facility with contracted water for irriga- tion, municipal and industrial, and water quality uses. Recreation is a major activity during the summer months on the reservoir. During the winter it serves as a flood control structure with 20,000 acre feet des- ignated for flood control storage from November to April. Clean Water Services: Clean Water Services (CWS) provides sanitary and stormwater services to the urban areas of Washington County. CWS has two major summer discharging wastewater treatment plants (WWTPs) that have permits to discharge water into the Tualatin River. The Rock Creek WWTP dis- charges an average of 50 cfs (33 MGD) at RM 38.1; the Durham WWTP discharges an average of 31 cfs (20 MGD) at RM 9.4. CWS also releases storage water from Scoggins and Barney Reservoirs for flow augmentation during the seasonal low flow periods. The goal is to maintain 150 cfs (100 MGD) at the Tualatin River at Farmington Road Bridge gage (RM 33.3).