Peter Martins, P.E., Project Manager From: David Carlson, Project Manager Carmen Nale, P.E., Project Engineer Date: August 27, 2012 RE:

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1 Capital Improvement Master Planning Services B&V File No. E 1.3 TECHNICAL MEMORANUM 03 To: Peter Martins, P.E., Project Manager From: avid Carlson, Project Manager Carmen Nale, P.E., Project Engineer ate: August 27, 2012 RE: Water Supply Needs 1.0 INTROUCTION 1.1 Overview The purpose of this technical memorandum (TM) is to review and update the Joint Water Commission (JWC) water demand projections and to validate water supply needs for the Water Supply Evaluation Project. This Project includes the investigation of additional water supply options. 1.2 Purpose The overall objective is to update the water demand projections and to validate water supply needs of the JWC. The scope of wor for TM03 includes the following: Update Hillsboro Water emand Projection. Update Tualatin Basin Water Supply Partner emand Projections. o Calculate the average day demand, pea day demand, and pea season demand for TVW, Hillsboro, Forest Grove, and Beaverton. State methodology and uncertainties provided by each entity. o Incorporate the storage water needs of Clean Water Service (CWS). o Aggregate water supply into consumptive and non-consumptive water needs for comparing drining water with wastewater treatment needs. o Summarize in tabular and graphical forms the individual and aggregate water demands and summer storage needs. 1.3 ata Sources The following is a list of the data provided by the JWC used for this TM: City of Forest Grove Water emands from Forest Grove-Supply-emand for JWC Alt. Analysis_ xlsx. Clean Water Service Water emands from emand Summary FINAL.xls. This spreadsheet was updated in a Technical Advisory Committee (TAC) team meeting April 27, 2010, by shifting the transition year from 2015 to 2020 to match the TVW switch from Portland supply to the JWC supply. Technical Memorandum 03 Water Supply Needs Page 1

2 Blac & Veatch Corporation Clean Water Services raft am Raise Technical Memorandum dated November 26, TVW Water emands from TVW emand Update Rev 1 Sept 2010.xls. This spreadsheet was updated by Hillsboro in January City of Beaverton from JWC-COBdemand41210.pdf. This spreadsheet was updated by Hillsboro in January Existing water rights from JWC Existing Storage Volumes.xlsx. 1.4 Study Area The study area includes the JWC and Clean Water Services (CWS). The JWC is a collective water supply agency formed under an ORS 190 agreement between the Cities of Hillsboro, Forest Grove, Beaverton, and TVW. The City of North Plains became a wholesale customer to the JWC in June The JWC treats water at its 75 million gallon per day (MG) maximum capacity water treatment plant (WTP) and distributes it on a wholesale basis to the member agencies, which in turn deliver water to area customers. The existing service area is shown on Figure 3-1. Through its member agencies, the JWC provides potable water for a service population of roughly 252,000. The ownership of facilities among the group includes raw water impoundment in Barney Reservoir, raw water storage contracts with the Bureau of Reclamation in Scoggins Reservoir, a 75 million gallon per day (MG) water treatment plant located along the Tualatin River, two 20 million gallon (MG) finished water reservoirs located atop Fern Hill, and three transmission lines that deliver finished water to the JWC members. As the 2050 planning horizon nears, it is anticipated that continued growth may lead to the extension of urban zoning and each JWC partner s water service area into new urban growth areas as permitted under Oregon statues. These growth areas are shown as potential urban reserves on Figure 3-1. These areas correspond to the areas approved by the Metro Council in Resolution # There are several third party wholesale agreements, through the City of Hillsboro, which allow other agencies to receive JWC water. The City of Gaston, LA Water Co-Op, and a portion of the Upper System can be fed from either the JWC WTP or the City of Hillsboro s Cherry Grove Slow Sand WTP. Currently these customers are served primarily from the Cherry Grove WTP and receive supplemental flow from the JWC WTP through the illey PRV. Prior to August 2004, the City of Cornelius was fed from the Cherry Grove Slow Sand WTP; in 2004 their service was switched to the JWC WTP. emands associated with these third party agencies are included in the demands for the City of Hillsboro. CWS is a special service district for the wastewater, stormwater and water resources management for the urban areas of Washington County. It serves twelve member cities and owns and operates four wastewater treatment plants. Technical Memorandum 03 Water Supply Needs Page 2

3 re re H N S R r ee ee LV R NM North A Plains Turnout S lo ug h # AN bia 1 TVW - Portland Water Bureau Turnout N AB lu m TL Co MB I O R LU P CO er N IN FA RM r iv e Project No.: Sources: LS BE AV ERTO N H IL ALE H W Y 60 e e H OL LS FE RR Y r e e h As Try on RB BA UR B 1 inch = 2 miles e W BO ON ES FE RR YR R R FE RR NE S CO UN T RY r ee go C O swe CL UB R MC V R e SHERWOO SE TUALATIN SH ERWOO R R ST AF FO RT R TU AL IN AT E RWO O SH R son ee ic PO GE Sau m C r ee Athe y ee Ch R re e C r ee nc I BR LAKE OEGO TUALATIN RIVERGROVE Y Roc hi c e HW IFIC PAC LS H IL o an y C n BO R YR H VA L L E G ee n NO RT ha l he OH WY C re e an d wl Ro re e R 65TH AVE W e st F o r ee ee Ceda r He ato C ul f n e e tc 2 Y B aer Sal AN RM BO O Ba ll URHAM L R R e CA KING CITY r ee e hi ll em Cart er ee WAY Spring Broo ee C ree re e ec RR Y HIL SPRI NG am M M c Fe FE C er C i ng URH A ILL R r e e C KRUS E ess GH r ee 47 W TIGAR M r ee in r ee re e lc oc ap at ll C C O LLS FERR Y R e re Hi h il ye rs ri s C B ur SC H IN SPR Ya m A BAL PEAK R r Fo G d oo R 1 LV S RIV ER ut h So I NG H ILL R SP R nc Canyon r ee L W OO R Joint Water Commission (JWC) City of Hillsboro Tualitin Valley Water istrict (TVW) Washington County Metro ata Resource Center Miles P IT OL H W Y CA BOR LAN R FIGURE 3-1 J W C W A T E R S Y S T E M M A P Wil ST am s ee U RE N E NV ER AVE ee illi N INTERSTATE AVE M ar qu W L A Litt le R uss ell G B T ee Gu lch Potential Urban Reserves O N FR W N A WA YA VE RO S E T HWY n y Ive ee T ual Urban Growth Boundary SU N R a n no Incorporated Area A va 54 Cities 405 ST Sy l re e 20 Su m me R 24 C lf HA LL BLV Go W BURN SI E ER County Boundary HWY SU NSET Y ET H W 11 I W BU R N S B N W S UNS 12 N R NYO Tigard Water Service Area am ES R at i IXON MILL R AR N BEAVERTON 20 City of Beaverton Service Area e ee nr r Ha Hi ll ee FRONT GASTON Wa patsow GA STO N R C an al se n B 24 SC R Ch r is ten WY 25 Joh n son e e 37 UNGER R SE TH 24 CA LL ON GT 21 R SU N F HI City of Hillsboro Service Area NW LOVEJOY ST nc ree MURRAY BLV G re e n 48 Be 30 H ILL SB O RI N sc r e e e Joh rn ut ee But te ng C s C re so n C 36 L R RNEL 30 r ee 30 r e e er C nc WY r do Go 36 C ll 42 t 42 re e W es se ng 24 om IN VALL EY HW Y TH AVE SE TU ALAT S W CO RNE LIU S PASS R H EY WY YH VAL LE UA LAT IN T NW CORNELIUS PASS R n ER e i ll C re e e e NW GLENCOE R WY B ST LL SE 10TH AVE IV RO H te r N 1ST AVE SUNS ET E ST ee r nn e Ta rp en 42 e e e tt R 72 R 405 er iv Bo t NW CO to n s o WY rm da Tualatin Valley Water istrict NW VAUGHN ST 7 PORTLAN r av e SP a vi SE TH y on R te HILLSBORO SU N SE R re e ow Bal ch C a n 6 R Jacson Slough 24 B ST Ja c 45 i SE BASELINE ST SE OAK ST W ee River YE ON AV E et am BASELINE ST OAK ST W OO R Waterbody NW Major Arterial 5 ES CORNELIUS BE R 3 ree ill W TUALATIN VALLEY H WY ee lc R NE C O R N E LL ns Bro NW AM re e on C S alt z 4 C ma n N 72 VA BASELINE ST so Freeway 42 R TIN LA aw e an o BA TU A Ca N ei JWC-Member istribution Main BASEMAP W ee ee ey JWC Transmission Main ST N G a e N AAIR ST 19TH AVE ee 24 C re NW 185TH AVE l ch 72 FOREST GROVE PACIFIC AVE e e ill BA R EM re e Gu ir y Cou n c il les der OM C ree b le C ar e xan NL E AV e ee Ale ey NA IT 16 E 26 r b le 45 GA L ES C REEK R K night en C r ee PIPES G ic A bb as 30 re e er C Hillsboro Turnout ill I BR s tr T ee e Me rc Beaverton Turnout Forest Grove Turnout WY a C ll Ha P:\254 - Joint Water Commission\002 - ASR Feasibility Study\Project_GIS\Project_mxds\BV_Figures\Revised_042309\Figure3-1_JWC_Water_System_Map.mxd w JWC-Member Treatment Plant NW i SE TH h B lac Ja c C ree ree JWC Treatment Plant McC a r ey NW NEH ALEM HWY ree SU N Wa Wa YAMHILL COUNTY re e t or R NW W R WASHINGTON COUNTY JWC Reservoir iver th yc e ee re K i tc ri LE Y ia R N LOMBAR ST ST S MAIN ST NW C ch ee b om us EE e t7 1 VA L E sc nni mb JWC-Member Reservoir NORTH PLAINS re Y MULTNOMAH COUNTY Jac son C Ho lc M JWC WTP PA TT ON e LE Y CR rai na g Henry Hagg E Colu er rt Riv e C ree W e ri 18 nn el ah Cha ra n e G ilb TVW Turnout Hi ll O h C re S Lae H JWC-Member Pump Station Ba BANKS JWC Pump Station om Mul tn W ir t z B so ed Bl N MAIN ST SE TH WY NW WI LS O N RI V E R H S LE ee WASHINGTON COUNTY yc c Ka M Y Roc gh W C r ee JWC Intae lo u H ay L E G E N FACILITIES ire S T SE M ck airy 30 o u gh N C anyo n e C re SU N anyo n Br id ge ee r N ei lc on SU Fo r Ash Slo ug e ee mm Gu ny W Cedar GA Sain ree re e st ee B uc m Ca or sc r ee Ea ch 47 NW illey Reservoir 1 Springville Reservoir 2 Thompson Reservoir 3 North Road Reservoir 4 Bonny Slope Reservoir 5 Bonny Slope Par Reservoirs 6 Cornell Reservoir 7 WILSO N RIV Teufel Reservoir 8 ER HWY Somerset Reservoir 9 Wh ite ee Sunset Reservoir 10 Rosander Reservoir 11 Inglewood Reservoir 12 Fir C Hyde Par Reservoir 13 Garden Home Reservoirs 14 I l e r Ln. Florence 15 ee Reservoirs Taylors Ferry Reservoirs 16 Schell Reservoir 17 Cooper Mt. Reservoir (TVW) 18 Goya Reservoir th Reservoir 20 e e r Grabhorn Reservoir 21 ar C Cle Evergreen Reservoir 22 24th Ave. Reservoir 23 Fern Hill hreservoirs 24 om Sexton Mt. Reservoir 25 Cooper Mt. Reservoir (Beaverton) 26 Booster Pump Station 27 ric C re ee de e p C Booster Pump Station R o 28 Hillsboro Pump Station 29 Forest Grove Pump Station 30 Pa rso Teufel 31 n s CPump Station r Sunset Pump Station 32 Inglewood Pumps 33 Viewmont #1 Pump Station 34 P35 r ic 189th Ave. Pump Station Goya Pump Station 36 Cooper Mt. Pump Station 37 Florence Ln. Pump Station 38 Bethany Pump Station 39 Viewmont #2 Pump Station 40 Catlin est Pump Station 41 Bannister Pump Station 42 Evergreen Pump Station 43 Sc og in s JWC gtreatment Plant 44 ee Forest Grove Treatment Plant 45 JWC Intae Pump Station 46 tf nc ur nt Vancouver Lae M ud Sl Garrigus e e an y ey C Pa isl c April 23, 2009 i sw Pa tterso e Eas a rm dc KEY I r F Pa S ad r ee ve NAME ee N a Be 20 tt le Reservoir I Other Facility I ai ry ee Li 20 un Br es t r Fo FACILITY KEY W Roc Ku de r C ree

4 Blac & Veatch Corporation 2.0 EMAN PROJECTIONS Updated JWC water demand projections from Year 2010 through Year 2050 were projected by each JWC partner and provided by the JWC for use in this TM. With the exception of the City of Hillsboro, independent projections were not evaluated or generated by Blac & Veatch as part of this TM. Conservation was factored into the Hillsboro demands by utilizing the more recent per acre water consumption use for each zone. The City has seen reductions of use on that basis due to the higher density and recent updates in water efficient plumbing standards. Climate change impacts on water supply were included in the projections by assuming 184-day release season over the term of the study and a reduction of Hillsboro s natural flow right availability by 25%. The reduction was based on a conservative estimate provided in a recent climate change study completed on the Tualatin River by the University of Washington s Climate Impacts Group, The Impacts of Climate Change on the Tualatin Basin Water Supply, (Palmer et al., 2005). The following types of demands are included in the updated demand projections for 2010 through 2050: Average day demands (A): A is the daily demand averaged over a one-year period. A summary of the A projections for 2010 through 2050 are shown in Table 3-1a (mgd) and Table 3-1b (cfs), and the corresponding Figure 3-2a (mgd) and Figure 3-2b (cfs). Pea day demands (P): P is the maximum daily demand over a one-year period. P can also be referred to as Maximum ay emand (M). P projections are typically calculated as the product of the A and the P peaing factor. Pea day demand (P) is the maximum quantity of water used on any one day of the year. The pea day demand is used to size water supply and water treatment infrastructure to ensure that reservoirs can be refilled following a day of pea demand. A summary of the P projections for 2010 through 2050 are shown in Table 3-2a (mgd) and Table 3-2b (cfs), and the corresponding Figure 3-3a (mgd) and Figure 3-3b (cfs). Pea Season emand (PS): PS is defined as the average pea season demand roughly during the summer months of July, August and September. o o For this Project, the 184 day pea season demand (184 ay PS) will be used to account for unnown impacts to future storage requirements caused by climate change, etc. The 184 ay PS is defined as the average PS during May 1 st through Oct 31 st. A summary of the average pea season demand projections for 2010 through 2050 are shown in Table 3-3 and the corresponding Figure 3-4a (mgd) and Figure 3-4b (mg and acre-ft). For comparison, the 160 day pea season demand (160 ay PS) was calculated since this corresponds to current storage requirements. The 160 ay PS is defined as the average PS during May 25 th through Oct 31 st. A summary of the average pea season demand projections for 2010 through 2050 are shown in Table 3-4 and the corresponding Figure 3-5a (mgd) and Figure 3-5b (mg and acre-ft). All demands presented in this memorandum are for JWC water use only and do not include JWC partner demands met by other sources unless otherwise noted. Technical Memorandum 03 Water Supply Needs Page 4

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6 Blac & Veatch Corporation Table 3.1a. JWC Partner Average ay emand Projections (mgd) City of Beaverton 4 City of Forest Grove 3 TVW 2 Total JWC A Previous Total JWC Local City of North Year JWC Total Supply JWC Total Hillsboro 1 JWC Portland Total Plains Notes: 1. City of Hillsboro based on JWC supplies all water. City of Hillsboro demands include City of Cornelius and City of Hillsboro Upper System (2007 thru 2050). See Revised Pea Season emand Calculations.xls, "emand by emand" tab for calculations. 2. TVW information based on TVW emand Updates - Rev 1 - Sept 2010.xls. 3. Forest Grove information based on Forest Grove - Supply - emand for JWC Alt. Analysis_ xlsx. 4. City of Beaverton based on JWC-COBdemand41210.pdf. Assuming 115 gpcd, previous ASR information per City of Hillsboro Jan Based on ecember 2005 Water System Master Plan (not updated 2010). Technical Memorandum 03 Water Supply Needs Page 6

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8 Blac & Veatch Corporation Beaverton 4 City of Forest Grove 3 Table 3-1b. JWC Partner Average ay emand Projections (cfs) City of TVW 2 Total Local City of North JWC Previous Year JWC Total Supply JWC Total Hillsboro 1 JWC Portland Total Plains 5 A Total JWC Notes: 1. City of Hillsboro based on JWC supplies all water. City of Hillsboro demands include City of Cornelius and City of Hillsboro Upper System (2007 thru 2050). See Revised Pea Season emand Calculations.xls, "emand by emand" tab for calculations. 2. TVW information based on TVW emand Updates - Rev 1 - Sept 2010.xls. 3. Forest Grove information based on Forest Grove - Supply - emand for JWC Alt. Analysis_ xlsx. 4. City of Beaverton based on JWC-COBdemand41210.pdf. Assuming 115 gpcd, previous ASR information per City of Hillsboro Jan Based on ecember 2005 Water System Master Plan (not updated 2010). Technical Memorandum 03 Water Supply Needs Page 8

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10 Blac & Veatch Corporation Table 3-2a. JWC Partner Pea ay emand Projections (mgd) City of Beaverton 4 City of Forest Grove 3 TVW 2 ASR Maximum Rate Total Total Total JWC P Previous Total JWC Local City of PWB North Year JWC Supply JWC Hillsboro 1 JWC ASR Metzger Total Plains Notes: 1. City of Hillsboro based on JWC supplies all water. City of Hillsboro demands include City of Cornelius and City of Hillsboro Upper System (2007 thru 2050). See Revised Pea Season emand Calculations.xls, "emand by emand" tab for calculations. 2. TVW information based on TVW emand Updates - Rev 1 - Sept 2010.xls revised on Feb 2011 per City of Hillsboro Jan JWC demands do not include ASR demands. TVW has native groundwater rights, but use them as an emergency bac-up supply due to water quality concerns and are not considered part of their current system supply. 3. Forest Grove information based on Forest Grove - Supply - emand for JWC Alt. Analysis_ xlsx. 4. City of Beaverton based on JWC-COBdemand41210.pdf. Assuming 115 gpcd, JWC demands do not include ASR demands. ASR maximum rate, reliability factor and demands per City of Hillsboro Jan Based on ecember 2005 Water System Master Plan (not updated 2010). Technical Memorandum 03 Water Supply Needs Page 10

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12 Blac & Veatch Corporation Table 3-2b. JWC Partner Pea ay emand Projections (cfs) City of Beaverton 4 City of Forest Grove 3 TVW 2 ASR Maximum Rate Total Total Local City of PWB North Year JWC Supply JWC Hillsboro 1 JWC ASR Metzger Total Plains Notes: 1. City of Hillsboro based on JWC supplies all water. City of Hillsboro demands include City of Cornelius and City of Hillsboro Upper System (2007 thru 2050). See Revised Pea Season emand Calculations.xls, "emand by emand" tab for calculations. 2. TVW information based on TVW emand Updates - Rev 1 - Sept 2010.xls revised on Feb 2011 per City of Hillsboro Jan JWC demands do not include ASR demands. TVW has native groundwater rights, but use them as an emergency bac-up supply due to water quality concerns and are not considered part of their current system supply. 3. Forest Grove information based on Forest Grove - Supply - emand for JWC Alt. Analysis_ xlsx. 4. City of Beaverton based on JWC-COBdemand41210.pdf. Assuming 115 gpcd, JWC demands do not include ASR demands. ASR maximum rate, reliability factor and demands per City of Hillsboro Jan Based on ecember 2005 Water System Master Plan (not updated 2010). Total JWC P Technical Memorandum 03 Water Supply Needs Page 12

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15 Blac & Veatch Corporation Max Total (mgd) ASR Max Rate (mgd) Table 3-3. JWC Partner Average Pea Season emand Projections {May 1st - Oct 31st (184 days)} City of Beaverton 4 City of Forest Grove 3 City of Hillsboro 3 TVW 2 North Plains 5 Total JWC PS ASR Reduced JWC 6 Local JWC 3,6 JWC 6 Total ASR JWC 2,6 JWC 6 Rate JWC JWC (Acre- Total Supply JWC 3 JWC 3 (Acre- JWC JWC (Acre- (Acre- ASR (Acre- JWC 2 JWC 2 (Acre- JWC JWC (Acre- (mgd) (mgd) (MG) Ft) (mgd) (mgd) (mgd) (MG) Ft) (mgd) (MG) Ft) Ft) (MG) Ft) (mgd) (MG) Ft) (mgd) (MG) Ft) (mgd) (MG) Reliability Year Factor % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % Notes: 1. City of Hillsboro based on JWC supplies all water. City of Hillsboro demands include City of Cornelius and City of Hillsboro Upper System (2007 thru 2050). See Revised Pea Season emand Calculations.xls, "emand by emand" tab for calculations. City of Hillsboro JWC storage demand equals JWC demand minus Hillsboro natural flow water rights. 2. TVW information based on TVW emand Updates - Rev 1 - Sept 2010.xls revised on Feb 2011 per City of Hillsboro Jan JWC demands do not include ASR demands. JWC (MG) total based on 180 day PS and 120 day ASR Reduced Rate. Total TVW storage is the TVW stated JWC storage less their ASR rate over 120-days so the total 1.5 billion gallon aquifer storage is not exceeded. TVW has native groundwater rights, but use them as an emergency bac-up supply due to water quality concerns and are not considered part of their current system supply. 3. Forest Grove information based on Forest Grove - Supply - emand for JWC Alt. Analysis_ xlsx. 4. City of Beaverton based on JWC-COBdemand41210.pdf. Assuming 115 gpcd, JWC demands do not include ASR demands. JWC (MG) total based on 184 day PS and 120 day ASR Reduced Rate. ASR maximum rate, reliability factor and demands per City of Hillsboro Jan JWC demand equals Max Total - ASR Reduced Rate. Total PS based on ASR information given for P and assumed the same for PS. 5. North Plains demands based on ecember 2005 Water System Master Plan (not updated 2010). PS based on City of Hillsboro WSA monthly factor per City of Hillsboro meeting 4/ Historical stored water information based on "JWC Stored Water Historical Use xlsx." JWC 6 (Acre- Ft) Technical Memorandum 03 Water Supply Needs Page 15

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18 Blac & Veatch Corporation Max Total (mgd) ASR Max Rate (mgd) Table 3-4. JWC Partner Average Pea Season emand Projections {May 25th - Oct 31st (160 days)} City of Beaverton 4 City of Forest Grove 3 City of Hillsboro 3 TVW 2 North Plains 5 Total JWC PS ASR Reduced Rate (mgd) JWC 6 (Acre- Ft) Local Supply (mgd) JWC 3,6 (Acre- Ft) JWC 6 (Acre- Ft) Total (Acre- Ft) ASR (Acre- Ft) JWC 2,6 (Acre- Ft) JWC 6 (Acre- Ft) (mgd) (MG) Reliability JWC JWC Total JWC 3 JWC 3 JWC JWC ASR JWC 2 JWC 2 JWC JWC Year Factor (mgd) (MG) (mgd) (mgd) (MG) (mgd) (MG) (MG) (mgd) (MG) (mgd) (MG) % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % Notes: 1. City of Hillsboro based on JWC supplies all water. City of Hillsboro demands include City of Cornelius and City of Hillsboro Upper System (2007 thru 2050). See Revised Pea Season emand Calculations.xls, "emand by emand" tab for calculations. City of Hillsboro JWC storage demand equals JWC demand minus Hillsboro natural flow water rights. 2. TVW information based on TVW emand Updates - Rev 1 - Sept 2010.xls revised on Feb 2011 per City of Hillsboro Jan JWC demands do not include ASR demands. JWC (MG) total based on 180 day PS and 120 day ASR Reduced Rate. Total TVW storage is the TVW stated JWC storage less their ASR rate over 120-days so the total 1.5 billion gallon aquifer storage is not exceeded. TVW has native groundwater rights, but use them as an emergency bac-up supply due to water quality concerns and are not considered part of their current system supply. 3. Forest Grove information based on Forest Grove - Supply - emand for JWC Alt. Analysis_ xlsx. 4. City of Beaverton based on JWC-COBdemand41210.pdf. Assuming 115 gpcd, JWC demands do not include ASR demands. JWC (MG) total based on 184 day PS and 120 day ASR Reduced Rate. ASR maximum rate, reliability factor and demands per City of Hillsboro Jan JWC demand equals Max Total - ASR Reduced Rate. Total PS based on ASR information given for P and assumed the same for PS. 5. North Plains demands based on ecember 2005 Water System Master Plan (not updated 2010). PS based on City of Hillsboro WSA monthly factor per City of Hillsboro meeting 4/ Historical stored water information based on "JWC Stored Water Historical Use xlsx." JWC 6 (Acre- Ft) Technical Memorandum 03 Water Supply Needs Page 18

19 Blac & Veatch Corporation 3.0 WATER STORAGE NEES The water storage needs of the JWC and CWS were determined based on the difference of total water supply demands and the existing water rights. 3.1 Total Stored Water emand The total water storage needs are based on the gross total pea season demand (PS) of consumptive (JWC) and non-consumptive (CWS) water use. The JWC total water storage needs are based on the 184 ay PS. The CWS water requirements are based on a 120 day period since they do not follow the typical municipal and irrigation (M&I) consumption model. The CWS water requirements are based on total volume of water needed to discharge from the reservoirs during the pea season demand period for four major purposes: 1. Ensure minimum stream flows in the Tualatin River 2. Offset a portion of the thermal load discharged by the Roc ee and urham AWTFs, 3. Offset the impact of sediment oxygen demand in the river 4. Water quality enhancement. The individual and total storage water demands are shown in Table 3-5 and Figure 3-6. Technical Memorandum 03 Water Supply Needs Page 19

20 Blac & Veatch Corporation Table 3-5. Consumptive (JWC) and Non-Consumptive (CWS) Total Water Supply & Storage Needs Non-Consumptive (120 ays Pea Season emand 1,2 ) Consumptive (184 ays Pea Season emand) Total Stored Water emand Stored emand emand Stored emand emand Year (mgd) (MG) (Acre-Ft) (mgd) (MG) (Acre-Ft) (MG) (Acre-Ft) Notes: 1. CWS total stored water demand needed discharged from reservoir during the 120 days PS period to meet water quality at WWTP discharge points. The 120 day PS period is not the assumed 184 day period, since demands don t follow the M&I consumption model. 2. CWS pea season was provided in the emand Summary FINAL.xls. Technical Memorandum 03 Water Supply Needs Page 20

21 Blac & Veatch Corporation 3.2 Total Existing Water Rights The existing water rights for JWC and CWS include stored water rights at Scoggins and Barney Reservoirs and natural flow. The individual and total existing water rights are shown in Table 3-6 and Figure 3-7. Agency Table 3-6. Existing Water Supply Scoggins Reservoir Natural Flow 184 ays Total Existing Water Supply Barney Reservoir (ac-ft) (ac-ft) (ac-ft) 2 (ac-ft) 2 Beaverton 4 3,912 3,360 7,272 Hillsboro 3 4,890 4, ,844 Forest Grove 4 4, ,792 TVW - 5,471 5,471 Total JWC Stored Water Supply (Scoggins and Barney Reservoir Only) 27,270 Total JWC Partner Water Supply 32,379 CWS 12,340 1,563 13,903 Total Existing Storage Water Supply (JWC & CWS) 1 25,543 15,630-41,173 Total Existing Water Supply (JWC & CWS) 25,543 15,630 5,109 46,282 Note: 1. Total existing storage water supply equals JWC stored water supply + CWS storage supply. 2. Hillsboro natural flow water supply not accounted for as a reduction in demand but included in the total water supply. 3. Climate change was addressed only by Hillsboro s adjustment of its natural flow rights reliability from 100% in 2010 to 75% in Reductions for fish flows, dead storage, and evaporation loss factors applied by the Washington County Water Master were applied to the storage allocations for Barney Reservoir. 5. Reductions for evaporation loss factors applied by the Washington County Water Master were applied to the storage allocations for Scoggins Reservoir. 6. Beaverton and TVW local ASR water supply is accounted for in the reduction of their individual demands, not included in the total water supply. Source: JWC Existing Storage Volume.xlsx Technical Memorandum 03 Water Supply Needs Page 21

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23 Blac & Veatch Corporation 3.3 Total Future Needed Water Storage Rights The total future supply and storage water needed was determined based on the difference between the total stored water demand and the existing water supply from year 2010 to year This is shown in Figure 3-8 and Table 3-7. Technical Memorandum 03 Water Supply Needs Page 23