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Home My WebLink About2011-0314 Study Session PACKET CITY OF ASHLAND CITY COUNCIL STUDY SESSION AGENDA Monday, March 14, 2010 at 5:30 p.m. Siskiyou Room, 51 Winburn Way 5:30 p.m. Study Session 1 . Look Ahead Review 2. Does Council have questions or feedback on the proposed effluent water temperature solution alternatives? [60 Minutes] In compliance with the Americans with Disabilities Act, if you need special assistance to participate in this meeting, please contact the City Administrator's office at (541) 488-6002 (TTY phone number 1-800-735- 2900). Notification 72 hours prior to the meeting will enable the City to make reasonable arrangements to ensure accessibility to the meeting (28 CFR 35. 102-35.104 ADA Title I). COUNCIL "IEETINCiS ARE BRO,\DC\ST LIVE ON CJI;\NNEJ. 9 VISIT TilE CITY OF !\SHIANJ)'S WEll SiTE !\T WWW!\SliL\ND.OR.US CITY OF ASHLAND Council Communication Meeting Date: Department: Secondary Dept.: Approval: Wastewater Master Plan Update Study Session March ]4,20]] Primary Staff Contact: Michael R. Faught Public Works . E-Mail: faughtm@ashland.or.us Administration Secondary Contact: Scott A. Fleury Martha Bennet Estimated Time: 60 Minutes Question: Does the Council have questions or feedback on the proposed effluent water temperature solution alternatives? Staff Recommendation: Staff recommends that Council review the attached documentation and provide input regarding implementation of the next steps. Background: At the June] 5,20] 0 council meeting, the council awarded the $303,400 wastewater master plan update to Keller and Associates. While the consultant has accomplished many of the scope of work items (evaluation of regulatory compliance, existing and future treatment plant flow and load projections, updated the collection system sewer model, wastewater treatment plan existing conditions evaluation) the most timely and critical work has been focused on developing options that bring Ashland effluent temperature into compliance with the new 2007 Bear Creek Temperature standards. The reason staff required the consultant to work on the effluent temperature compliance issue as the highest priority is that the City's National Pollutant Discharge Elimination System (NPDES) Permit (which are on a five year cycle) is up for renewal and the new NPDES permit has to include a plan for the City to meet the new Bear Creek TMDL standards. To that end the consultant has been working closely with both Ashland and DEQ staff to develop a list of six potential effluent temperature compliance alternatives (Reuse on Imperatrice property or partial reuse on Imperatrice property, discharge into the TID system, cooling towers, trading/shading, blending/flow augmentation, and hyporheic or shallow groundwater discharge). The consultant has evaluated the pros and cons and costs of each of the proposed options and the results of that work are demonstrated in the following table: Pa~e I of3 ~~, CITY OF ASHLAND Table I: Description I Capital Aonual Prf.'jed Cost Cn~t Option ---- - ...1:1(mCIlI!i m ~ - UenetiB____J)I'UwbuckL _______ - ~ ______~I~~ _tomU1ent~ --- - Maximum Irrigate 433 Beneficial use of High Cost. $10.8 M $(58,000) $JO.IM Savings Reuse on acres with water. lower stream flows. assume thai lmperatice treated effluent. Existing water right membranes Property Pipeline to site, could be used to arena! 138-166 MG augment potable waler used. storage. supply. Shoulder season Potential for storage required membrane and I winter chemical savings. discharge. Mitigate concerns of "future" more stringent rCQulalions. Partial Reuse Lower cost does Similar to Option I A. High Cost. $5.3- $35,000 $5.8- For lower on Impertatice includes Improvement could be Introduces complexities 8.9M 9.4M cost range, Property -- minimum completed later if in monitoring and need to add 424 ac.fiIyr storage. Option 3 or 4 is wastewater management. cost of Higher cost pursued. Higher O&M costs than Option 3 or assumes more ' Option 1 A. 4, to address storage, and Reduced stream flows cooling periods of no available for aquatic requirement discharue. habitat. Discharge to Pipeline to Mitigate "near field" Not a standalone solution Not Not Not TID Talent Canal. concerns. u still need to offset Evaluated Evaluated Evaluated Reduction in chemical excess thennalloads. costs. High op)X)sition from downstream users anticipated. District concerns about chemicals. Storage for shoulder seasons likely required. Schedule and approval outside ofCitvcontrol. Cooling Tower ' Mechanical Addresses temperature Chillers required for $6.1 - $200,000 $8.6- Cost range cooling tower. concerns. hottest periods. 8.1M 11.6M reflects use Storage Allows continued Upstream / downstream of ponds facilities. discharge. storage also required for versus Maximum control in night.time operation concrete terms of compliance storage schedule. , reservoirs Trading 8 miles of Lowest cost Some uncertainty u $3,400,000 spread out $2.7M (Shading) shading. alternative. participating property over 20+ years Channel to Bear Allows continued owners to be identified; Creek. discharge. migration blockage Constructed Improved fish habitat evaluation to be wetland pond. and other completed. Potential environmental minor additional local benefits. coolinp rf"nuired. Blending / Blend additional Additional stream Cannot meet temperature Not Not Not Nota Flow water discharges flow. targets by itself. Evaluated Evaluated Evaluated viable Augmentation from Ashland Uses water that could be alternative. Creek or TID. used for potable water usage. Additional water quality testing may show additional water quality concerns. Hyporheic Subsurface Low operations costs. Difficulty in locating site Not Not Not (shallow dis)X)salof Simple technology. with suitable soils. Evaluated Evaluated Evaluated groundwater) treated Significant additional wastewater to effort required to shallow ground determine feasibility. water. Potential large land reauirement. Page 2 of3 ~~, CITY Of ASHLAND It is important to note that with the exception of the temperature trading or shading, most of these options are not new effluent temperature compliance concepts to Ashland. The shading concept looks at the benefits allowing communities the option of shading along the stream channels within the watershed as a system-wide solution to 'stream temperature reduction rather than trying to solve effluent temperature compliance at wastewater treatment plant outfall. This concept has either the City or a third party securing easements along the waterway at critical areas where shading is needed, and then provides long-term funding to plant and maintain the shading materials for 25 years. The resulting temperature reduction is then calculated and the city receives the temperature reduction credit at the wastewater treatment plant outfall. While this concept had some initial compliance challenges that have been worked out with DEQ, the consultant and staff will be recommending trading/shading as the preferred alternative to meet the new Bear Creek temperature standards. Because the trading/shading as an option to meet temperature compliance is new to our community, the DEQ Director has agreed to attend the Council study session to provide additional insight as to DEQ's view of trading/shading as a solution to temperature issues. Next Steps . Finalize effluent temperature compliance option recommendation for NPDES permit development . Technical Review Committee meeting March 15.2011 . Consultant will continue to develop master plan scope items . Public Outreach: Public Works would like recommendations on the extent of public outreach required to inform citizens on a course of action for implementation of the preferred disposa] option. Related City Policies: City of Ashland NPDES DEQ Permit Council Options: The Councils comments and directions regarding the next steps to be taken are encouraged and appreciated. Potential Motions: No motions are presented at this study session. Attachments: 1. TRC Meeting Agenda 2-23-201 I 2. TRC Meeting Minutes 2-23-2011 3. Wastewater Master Plan Draft Chapter 10 4. DEQ Memorandum - City of Ashland excess thermal loads limits Pagd on r~' CITY OF ASHLAND Wastewater Technical Review Committee AGENDA WASTEWATER TREAMENT PLANT 1195 OAK ST. February 23.20111:00 PM ATTENDEES I INTRODUCTIONS: AI Large Member (Chamber of Commerce), Meiwen Richards At L'<lrge Member, Jeff Heglie . AI Large Member, Joe Graf . Council Member, Russ Silbiger . Ashland Public Works Director -Mike Faught Ashland Engineering Technician -Scott Fleury Ashland Engineering (overseeing Water Study) - Pieter Smeenk Ashland Public Works Superintendent -Terry Ellis Ashland WastewaterlReuse Supervisor -David Gies Ashland Wastewater Coilections-Jerry Conley Ashland Wastewater Treatment Plant Supervisor-Ken Moser . Ashland Water Quality Conservation Analyst-Robbin Pearce . Medford Regional Water Reclamation Facility Superintendent, Dennis Baker . Environmental, Lesley Adams Rogue Riverkeeper Klamath-Siskiyou Wildlands Center Department of Environmental Quality - Jon Gasik & Ranei Nomura Department of fish and Wildlife - Dan Vandyke . Keiler Associates (Consulting Engineer) - James Bledsoe & Larry Rupp . Rogue Vailey COG - Craig Harper (Rogue Valley COG) . Fresh Water Trust - David Primozich OVERVIEW OF MASTER PLAN: . Collection system . Wastewater treatment and disposal eva1uations to meet TMDL / Permit requirements . Key deliverables of planning efforts: o Report that documents existing and future needs o Capital improvement plan o Master plan with prioritization and phasing of improvements o Financial plan with user rate and system development charge implications REVIEW OF WORK PREVIOUSLY COMPLETED: . Population and land use o Provided by the City o Study area coincides with UGB C:\Documents and Settings\shipletd\Local Setlings\Temporary Internet Files\Content.Outlook\63KU614S\Attach 1 TRC Agenda.doc . Design flows - developed using DEQ methodology; consider 5-year wet weather event and 10-year dry weather event . Treatment evaluation focuses on 20-year projections; collection system evaluation considers "build-out" projections . Collection system evaluation - just beginning now that flow monitoring is complete WASTEWATER TREATMENT FACILITY EVALUATION: . Draft write-up completed . Summary of existing deficiencies o RAS pumps capacity o Membranes Replacement o UV capacity to meet peak flows o The outfall pipeline is also a potential bottleneck, for peak flows, but this may be resolved as part of the Temperature option. . Improvement alternatives being considered REGULATORY REQUIREMENTS: . NPDES Permit (Clean Water Act) Issues o 1992 Total Maximum Daily Loads (TMDLs) . Phosphorus, ammonia, chlorine o 2007 TMDLs . Temperature . Future? New ammonia standards, pharmaceuticals o Other regulatory concerns . Water rights . Temperature concerns - DEQ Draft Tech Memo completed o Near field - local impacts to fish caused by a thermal plume . DEQ has internal guidelines for evaluating . Continued discharge to Ashland C~eek -- spawning impairments, thermal shock, and migration blockage . Relocating to Bear Creek - minor migration blockage in September o Far field - general watershed impacts addressed in TMDL ALTERNATIVES TO ADDRESS TEMPERATURE CONCERNS: o Draft Chapter 10 completed . Refer to summary table attached o Option 1: Reuse . Most expensive initial cost . Existing water rights available for potable water system . Flow is removed from creek - ODFW would want replaced (negates water right benefit?) . Options involving continued WWTP discharge during low stream flow periods would trigger additional improvements (i.e. Option 3 or 4) o Option 2: Discharge to TID - does not appear to be viable at this time o Option 3: Cooling Tower . Chillers and storage required C:\Documents and Setlings\shiph!td\Local Sellings\Temporary Internet Files\Content.Outlook\63KU614S\Attach 1 TRC Agenda.doc . Ongoing energy costs o Option 4: Trading (shading) . Lowest cost option . Other environmental benefits . Near field impacts mitigated by relocating outfall to Bear Creek, wetlands shading I shallow ground water interaction - potential that more than existing wetlands will be required _ . Keller Associates would recommended extended compliance period to address near field issues (i.e. 10 years) recognizing that 1) hyporheic action and shading in the channel and wetlands, 2) other shading activities upstream of the outfall, 3) additional flow and temperature data, 4) possible future changes in regulations, 5) possible reduction in discharge if reuse is pursued, and 6) possible other future activities may show that additional improvements are not necessary o Option 5: Blending - does not appear to be viable o Option 6: Hyporheic . not enough information to fully evaluate at this time . preliminary indicators suggest that this option could be land intensive, with potential difficulties in finding land near Bear Creek with suitable soils NEXT STEPS: . Define public outreach approach . March 14'h Council study session with DEU, 15th Meeting with City Council . Identified preferred treatment alternatives . NPDE5 Permit processing C:\Documents and Settings\shipletd\Local Settings\Temporary Internet Files\Content.Outlook\63KU614S\Attach 1 TRC Agenda.doc Table 10.2 - Ashland WW Disposal Option Comparison Chart Descriptfon I Capital Annual Proj~&%u:", 1 Cost Cost ~OP!!Qn_E!<l_~!!l!nel!\L~Or.wback._____N~V_Co!!l!ne.!!!L 1A Maximum Irrigate 433 Beneficial use of High Cost. $14.1 M $(58,000 $13.4M Savings Reuse on acres with water. Lower stream flows. ) assume Imperatice treated effluent. Existing water right that Property Pipeline to sile, could be used to membranes 138-186 MG augment potable are not storage_ water supply. used. Shoulder season Potential for storage required membrane and I winter chemical savings. discharge. Mitigate concems of "future" more strinaent rP.CIulations. 18 Partial Similar to Option 1 A. High Cost. $11.7 - $53.000 $12.4 - Additional Reuse on Introduces complexities in 12.4M 13.0M costs for Impertatice monitoring and wastewater cooling Property - management. would be Periods of Higher O&M costs than required for No Option 1A. discharge Discharge Reduced stream flows during each available for fish. month. 2 Discharge to Pipeline to Mitigate -near field- Not a standalone solution - Not Not Not TtD Talent Canal. concerns. - still need to offset excess Evaluate Evaluate Evaluate Reduction in chemical thermal loads. d d d costs. High opposition from downstream users anticipated. District concerns about chemicals. Storage for shoulder seasons likely required. Schedule and approval outside of Citv control. 3 Cooling Mechanical Addresses Chillers required for hottest $6.1 - $200,000 $8.6 - Cost range Tower cooling tower. temperature periods. 8.1M 11.6M reflects use Storage facilities. concerns. Upstream I downstream of ponds Allows continued storage also required for versus discharge. night-time operation concrete Maximum control in storage terms of compliance reservoirs schedule. 4 Trading 8 miles of lowest cost Some uncertainty - $3,400,000 spread $2.7M (Shading) shading. alternative. participating property out over 20+ years Channel to Bear Allows continued owners to be identified; Creek. discharge. migration blockage Constructed Improved fish habitat evaluation to be wetland pond. and other completed. Potential minor environmental additional local cooling benefits. r<:>nuired. 5 Blending I Blend additional Additional stream Cannot meet temperature Not Not Not Not a viable Flow water discharges flow. targets by itself. Evaluate Evaluate Evaluate alternative. Augmentatio from Ashland Uses water that could be d d d n Creek or 110. used for potable water usage. Additional water quality testing may show additional water quality concems. 6 Hyporheic Subsurface low operations costs. Difficulty in locating site Not Not Not (shallow disposal of Simple technology. with suitable soils. Evaluate Evaluate Evaluate groundwater) treated Significant additional effort d d d wastewater to required to determine shallow ground feasibility. water. Potential large land r<:>nuirement. NEXT MEETING DATE: March 15'h, 2011 1 :00 PM C:\Documents and Settings\shipletd\local Settings\Temporary Internet Files\Content.Outlook\63KU614S\Attach 1 TRC Agenda.doc Call Scott al 552-24 I 6 if vou will be unable 10 attend! In compliance with the Americans with Disabilities Act, if you need special assistance to participate in this meeting, please contact the City Administrator's office at (541) 488-13002 (TTY phone number 1-800-735-2900). Notification 48 hours prior to the meeting will enable the City to make reasonable arrangements to ensure accessibility to the meeting (28 CFR 35. 102-35.104 ADA Title I). C:\Documents and Settings\shipletd\Local SeUings\Temporary Internet Files\Conlent.Outlook\63KU614S\Attach 1 TRC Agenda.doc ~:., , W ASTEW A TER TECHNICAL REVIEW COMMITTEE (TRC) February 23RD, 2011 MINUTES MEMBERS PRESENT: JOSEPH GRAF, LESLEY ADAMS, MEWIEN RJCHARDSON, DENNIS BAKER STAFF: SCOTT FLEURY, TERRY ELLIS, DAVID GIES, JERRY CONLEY, KEN MOSER CONSULTANTS: JAMES BLEDSOE, LARRY RUPP MEMBERS ABSENT: JEFF HELGlE, RUSS SILBIGER, ROBBIN PEARCE, MIKE FAUGHT Visitors: Jon Gasik (DEQ), Ranei Nomura (DEQ), David Primozich (Freshwater Trust), Alan Horton (Freshwater Trust), David Laurance (Freshwater Trust), Dan Vandyke (ODFW) I. CALL.TOORDER: I :00 PM 2. APPROVAL OF MINUTES: No previous minutes to approve. Additional Items: None 3. Public Forum: No comments 4. OLD BUSINESS: None 5. NEW BUSINESS: A. Round Table Introduction: All members of the committee introduce themselves and provide a basic background. Bledsoe asks if anyone has any questions before critical items are discussed. B. Master Planning Overview: Bledsoe provides a general overview of the master planning process to committee members. The master plan is a snapshot in time of the current collection and facilities system along with a road map of where the system is headed over an extended planning period. C. Previously Completed Work: Bledsoe reviews the work completed by Keller to this point in the process. Keller Associates has been working on master plan scope items for approximately 6 months now and have completed some tasks with a focus towards effluent disposal options. Keller has also evaluated the treatment plant and provided the City with draft chapter 9, "Treatment Plant Existing Conditions" and chapter 10 "Effluent Disposal Alternatives". Committee members will be provided a copy of draft chapter 10 with minutes from TRC meeting, with the hope that comments from the TRC members may be received by March 7, 2011. Keller Associates will try to have a draft chapter 9 that incorporates City and DEQ comments prior to the next scheduled meeting. D. Regulatory Requirement: Jon Gasik from DEQ gives brief overview of the Clean Water Act and how it relates to the National Pollution Discharge Elimination System (NDPES) permit process. The Clean Water Act established water quality standards for municipalities to follow with regards to discharges into watersheds. DEQ performed tests on waters to determine if waters met the established standards. If they did not, then DEQ created Total Maximum Daily Level (TMDL) permits for point source discharges. In 1992, a TMDL was developed for the Bear Creek Watershed. AsWand has a point source discharge that is part of C:\Documents and Settings\shipleld\Local SeWngs\Temporary Internet Files\Content.Oullook\63KU614S\Attach 2 TRC Minutes.doc the Bear Creek Watershed and thus must follow a DEQ developed NPDES permit. The TMDL permits developed by DEQ for point source discharges are good for five years. At the end of each five year permit iteration a renewal process begins and new permits include updated standards that have been developed. The 1992 Bear Creek TMDL developed included phosphorus, ammonia and chlorine load allocation requirements. These requirements where addressed as part of the 1998 wastewater treatment plant upgrade. The 2007 Bear Creek TMDL develops load allocations for temperature, bacteria, and sediment. Out of these new standards for load allocations the primary focus for Ashland is the temperature requirements for effluent. Through the NDPES permit the City must address "far field" impacts and "near field" impacts with regards to temperature. DEQ has provided an analysis to Keller Associates and the City that the current effluent discharge into Ashland Creek creates near field temperature impacts that include fish migration blockage, thermal shock, and spawning effects during particular months of the year. In order to meet the new NDPES permit requirements the City must address these near field issues with a compliance schedule developed with the approval of DEQ. With respect to the far field impacts, over the past couple of years new protocols and procedures have been developed that make temperature trading a more viable option to address the far field TMDL concerns for the City of Ashland. Temperature trading is a kind of creekside riparian restoration that involves planting trees and vegetation to block the solar impact to waters. The City will need to meet both near field thermal requirements and far field heat load reduction as part of a new NDPES permit. Not only with temperature trading assist the City in meeting far field heat load allocations, but it provides a proven ecological benefit via riparian restoration. E. Disposal Options: Bledsoe reviews the 6 disposal options attached as part of the Agenda. E.I: Reuse (or Recyle): This option involves taking treated effluent and irrigating a portion of the City owned Impertrice property. This option was previously considered as an alternative to address phosphorous removal in the 1990s, but was reportedly not pursued at that time because of concern about removing water from receiving waters. The reuse could eliminate both near field and far field concerns by eliminating discharges during most of the year. Eliminating discharges during critical time periods would require a large volume of effluent storage. This is the most expensive cost option to address temperature concerns. One advantage of reuse, is that the existing 424 Ac*ft of water rights on the Impertrice property could be made available for potable water system. Based on water master planning efforts, a variation of this alternative could be one of the lower cost options to address anticipated future shortfalls in the City's potable water supply. A drawback ofreuse is that flow is removed from Ashland Creek - and ODFW would want some of the flow replaced, especially during critical low flow periods. This would negate some of the water right benefit. Options involving continued WWTP discharge between April and November would trigger additional improvements to address both near field and far field impacts of adding warm effluent to receiving waters (i.e. Items E.3 or EA below). E.2: Dishcharge to T.I,D: After meetings with the T.1.D Board of Directors by Keller Associates and city staff, too many concernslobstacles where developed to proceed with this option within the required time frame for permit renewal. E.3: Cooling Towers: Mechanical cooling towers could be constructed that would allow the city to meet the temperature requirements for effluent discharge. These cooling towers would also require chillers and storage for the hottest periods of the C:\Documents and Settings\shipletd\Local Settings\Temporary Internet Files\Content.Outlook\63KU614S\Attach 2 TRC Minutes.doc 2 year. The cooling towers would meet both the near field and far field impacts for the temperature requirements. This option is not viewed as a green alternative because of the ongoing energy costs. E.4: Temperature Trading: David Primozich reviews temperature trading with the committee. The Freshwater Trust developed a model of Bear Creek that shows riparian sections that can be shaded with trees and vegetation to reduce solar impacts. This alternative addresses the far field concerns by offsetting excess thennalloads from the treatment plant by shading approximately 8 miles of Bear Creek. Near field concerns would be addressed by relocating the existing outfall to Bear Creek and constructing some wetlands. Trading is considered the lowest cost option. Trading provides environmental benefits by the restoration of fish habitat. Keller Associates would recommend an extended compliance period to address near field issues (i.e. 10 years) recognizing that I) hyporheic action and shading in the channel and wetlands, 2) other shading activities upstream of the outfall, 3) additional flow and temperature data, 4) possible future changes in regulations, 5) possible reduction in discharge if reuse is pursued, and 6) possible other future activities may show that additional improvements are not necessary. Pursuing this alternative would not preclude the City from pursuing other alternatives including cooling and recycling water in the future. As part of relocating the outfall to Bear Creek, other concerns expressed by ODFW can be addressed. These include, preventing fish from swimming into the effluent line of the treatment plant, possibly removing the influent pipeline to the existing pond/wetlands, and modifying the outfall from the existing pond/wetlands. E.5: Blending: Two concerns were discussed with blending. First, temperature data gathered suggests that the likely source of water for blending (TID) has temperatures that exceed the target levels. This effectively makes it impossible to meet the TMDL requirements during certain periods of the year. Second, some concerns were expressed about the water quality of the TID sources. E.6: Hyporheic: Hyporheic is the subsurface disposal of effluent through shallow groundwater. This alternative was previously recommended as the preferred alternative. After additional investigation by Keller Associates, preliminary indicators suggest that this option could be land intensive, with potential difficulties in finding large amounts of land near Bear Creek with suitable soils. 6, FINAL COMMENTS: The City and Keller Associates would like the committee members to review disposal options and provide comments back. The City and Keller plan to have a study session with the City Council in March to discuss effluent disposal options. The City will provide minutes and the draft chapters to the committee as soon as possible. In addition, the City would like to discuss the extents of its public outreach program with committee members with regards to disposal options and the master planning process in general. 7. NEXT MEETING DATE: March 15'\ 1:00pm at the Wastewater Treatment Plant ADJOURN: Meeting adjourned at 3:10 I C:\Documents and Settings\shipletd\Local Settings\Temporary Internet Files\Content.Outlook\63KU614S\Attach 2 TRC Minutes.doc 3 _ COMPREHENSIVE SANITARY SEWER MASTER PLAN . ~~.~ 10,0 EFFLUENT DISPOSAL ALTERNATIVES 10.1 BACKGROUND During certain periods of the year, the wastewater effluent from the City's treatment plant accounts for a significant portion of the flow in Ashland Creek and Bear Creek. Higher effluent temperatures can raise the temperature of the creek and negatively impact aquatic habitat. DEQ will include new standards for excess thermal load limits when the NPDES permit for the City of Ashland's wastewater treatment plant (WWTP) is renewed to address the waste load allocation in the TMDL. DEQ may also include a temperature limit to address local impacts to aquatic habitat. Current effluent temperatures have the potential to exceed allowable levels for the May through October period. Keller Associates reviewed the previous five years of temperature and flow data, and determined that there is an existing excess thermal load of approximately 44 million kcal/day (critical month is October). This is anticipated to increase to approximately 53 million kcal/day by 2030. Similar calculations by DEQ correspond to Keller Associates' calculation results [1]. Reducing the excess thermal load from the Ashland WWTP is important in meeting target downstream temperatures in Bear Creek. An evaluation of wastewater disposal options completed in 2009 [2] looked for strategies or alternatives to address the excess thermal loads. This master plan builds upon the work previously completed. Additionally, since the completion of 2009 evaluation, guidelines for evaluating the local (near field) impacts and temperature trading programs have been more fully developed by the State. Representatives from DEQ, the City of Ashland, Keller Associates, Oregon Department of Fish and Wildlife (ODFW), and other stakeholders met on several occasions to better define the impacts of Ashland's wastewater discharge. DEQ completed a thermal plume analysis for continued discharge to Ashland Creek as well as discharge to Bear Creek. Because of concems with near field spawning impairments, thermal shock, and migration blockage, it is unlikely that continued discharge into Ashland Creek would be permitted without first significanUy cooling the effluent [1]. Relocating the outfall to Bear Creek would eliminate concerns of thermal shock and greaUy mitigate other near field impacts. Based on 3D modeling completed by DEQ, a side bank discharge would allow discharge to Bear Creek without impairing spawning. However, based on historical data, there still remains a potential for migration blockage during the month of September [1]. Keller Associates' scope of work for this study was to update the evaluation for the three most promising disposal alternatives. However, because of continued interest on the part of the City and new developments, six alternatives were evaluated in more detail. The findings of this evaluation follow. 10,2 REUSE OPTIONS Reuse options include those options that recycle treated wastewater. Land application of wastewater effluent during the growing season could reduce or eliminate the discharge of thermal loads to Ashland and Bear Creek during critical periods. Another benefit of reuse is that the treatment process is likely to be less affected by future changes in regulations requiring increasingly more stringent levels of treatment for discharge. For example, had the City of Ashland chosen to land apply their effluent rather than remove phosphorous via nRAIT CITY OF ASHLAND Page I February 2011 COMPREHENSIVE SANITARY SEWER MASTER PLAN KELLER eaoci.ta8 membrane filtration 10 years ago, they would not now be faced with addressing temperature concems. As discussed in Chapter 2, two items on the horizon that may affect future discharge requirements for the plant include 1) stricter ammonia limits, and 2) Oregon Senate Bill 737, which addresses pharmaceuticals. In addition to regulatory benefits, recycling water has the potential to offset potable water demands and make better use of available water resources. Maintaining stream flows has been a priority to the City in the past. One of the drawbacks with any reuse altemative that involves removing the existing discharge flow from Ashland Creek is that the recycled water would not be available for use for potential downstream users or to create higher flow conditions for aquatic habitat. From a water rights standpoint, the City of Ashland is not required to keep their effluent discharge in the creek. However, according to ORS 537.132, the following would occur if the City were to move forward with removing their flow for reuse purposes: . The Department of Water Resources (DWR) would notify affected users if discharge from Ashland WWTP to Ashland Creek were to cease (this because Ashland has discharged for more than 5 years and the WWTP discharge may at times make up 50% or more of the flow). . An affected downstream water right holder would need to demonstrate to DWR that the "cessation of discharge by the municipality substantially impairs the ability to satisfy a water right. . .. and if this person is successful, they would get preferential use of the reuse water. . The City is not required to incur additional expenses (beyond a more favorable altemative) to deliver water to the affected penson desiring the reuse water. 10.2.1 Recycling Water (Reuse) on Imperatrice Ranch Property The City has property north of 1.5 (Imperatrice Ranch) that could be used for crop irrigation using effluent. A conveyance pipeline crossing Ashland Creek was constructed when the City was considering a project in 1997 for biosolids application, effluent storage and irrigation on the pro~rty. Due to steep terrain and other limiting features (Talent Irrigation District canal, wetland swale), portions of the Imperatrice site are not useable for irrigation. Limiting irrigation to slopes less 20% and providing necessary buffer zones for the canal, swale and property lines provides a usable irrigation area of 412 acres for Class C effluent, or 433 acres for Class B effluent (smaller buffer to property lines) (3). One of the primary benefits the City would realize with recycling water on the Imperatrice Ranch property is that the water rights currently used there could be transferred and used as additional water supply for the potable water system. Two recycling options are summarized for the Imperatrice Property - Option 1A includes maximizing the total amount of water recycled on the property, and Option 1B includes recycling only the amount necessary to offset the existing water rights. Regardless of the disposal option selected by the City, Keller Associates recommends that the City work with DEQ so that future NPDES permits allow for recycling of treated effluent. nRA~ CITY OF ASHLAND Page 2 February 2011 COMPREHENSIVE SANITARY SEWER MASTER PLAN KELLER ..aoDi.cae 10.2.1.1 Option 1A: Maximum Reuse on Imperatrice Property The potential for thermal shock and migration blockage in Ashland Creek would be averted by eliminating discharge from June through October, and potential salmonid spawning impairment from thermal discharges would be prevented by reducing/eliminating discharge during November and March through May. Storage volumes for this option were determined based on irrigating as much land as possible without supplemental water, and discharging excess to the creek only to the extent that impairment of salmonid spawning is avoided. This results in limited discharge during March, April and November, and discharge of stored excess during January and February when creek temperatures are low enough to easily accommodate the thermal load. Alfalfa, pasture grass, and grass seed are potential crops; pasture grass and grass seed use more water than alfalfa and thus have lower storage requirements. Based on average net irrigation requirements and 70% irrigation efficiency, the acreage available on the Imperatrice property is sufficient to use 442 MG or 492 MG if planted to grass seed or pasture grass, respectively. Since the amount applied to crops is less than influent flows to the WWTP, the remainder would be discharged. At year 2030 flows (average 2.59 mgd), storage would be needed to provide sufficient volume during June, July and August. Additional storage volume would allow excess flows to be stored for discharge in the winter. An irrigated area of 433 acres of pasture grass would handle (without supplemental water) up to 2.77 mgd, with a storage volume of 138 MG (water balance in Appendix). A total of 512 MG would be discharged to the creek from November through April. The same acreage in grass seed would handle year 2030 flows with a storage volume of 139 MG and 496 MG discharged (November through April). The estimated project cost for Option 1A is approximately $10.8 million. Eliminating the need for phosphorus removal required for surface discharge would result in annual savings of $71,000 a year for alum. An estimated additional $100,000 potential annual savings could be realized in energy and chemical (sodium hypochlorite and citric acid) with elimination of the membrane operation. However, it is understood that the public perception may require the continued use of the membranes. If membrane operation were eliminated as part of the reuse option, the combined savings ($171,000) would more than offset the estimated $113,000 annual costs of pumping to storage on the site and from storage to irrigation. Though effluent quality would still need to be monitored with reuse, testing requirements (and related costs) are expected to decrease with the elimination of discharge. 10.2.1.2 Option 1B: Partial Reuse on Imperatice Property Keller Associates also evaluated an alternative that would recycle just enough effluent to offset the existing 424 ac-ft of irrigation rights on the Imperatrice property, and maintain the remaining flow in the stream. This scenario would allow the water right to be transferred to the City's potable water system and would also allow continued discharge to the creek. However, under this scenario, the temperature requirements of the TMDL would have to be met by employing other improvement alternatives. To offset the 424 ac-ft water right, enough water would need to be supplied to irrigate approximately 136 acres of land. The amount of storage required would depend on how much is discharged during specific periods of time. If minimum storage were provided, then close to half of the existing discharge during July and August would be used for irrigation, while the balance would be discharged to the creek. With additional storage, discharges nRAFT CITY OF ASHLAND Page 3 February 2011 COMPREHENSIVE SANITARY SEWER MASTER PLAN KELLER alNlOCi.~ could be eliminated during specific periods and restricted during others to eliminate the need for additional treatment to reduce thermal and phosphorus loads for discharge. (Existing alum and membrane treatment would still be required.) This approach would require close monitoring to consistently meet the discharge limits. If the City's primary objective is to maximize the discharge available during critical periods for aquatic habitat while offsetting the water right, this alternative could be adjusted to include increased storage during high stream flow periods and continued effluent discharge during low flow and spawning periods. The estimated project Cost for Option 1 B, not including a cooling component, is approximately $5.3-8.9 million (includes 6.5-168 MG storage). Since discharge to the creek would continue, all the costs for phosphorus removal discussed above would be included in the annual operation and maintenance cost of this option. In addition, there would be the added costs (estimated $35,OOOlyear) of pumping to storage on the site and from storage to irrigation. 10.2.2 Option 2: City.wide Reuse City-wide reuse (on parks, golf courses and other public spaces) was evaluated as part of the water master plan as an alternative to reduce potable water use [4]. From an implementation standpoint, Keller Associates would envision this being phased in over many years. Reuse on City property could be phased with agricultural reuse on the Imperatrice property. Since the distribution system for city-wide reuse may be extensive, the cost for implementation will exceed that of the option to apply all effluent to the Imperatrice property. In addition, storage during shoulder seasons would still be required for temperature TMDL compliance (storage location could be at Imperatrice property). 10.3 RELOCATED DISCHARGE OPTIONS 10.3.1 Option 3: Discharge to Talent Irrigation District (TID) This altemative would involve discharging the City's effluent into the TID irrigation system. The likely discharge location would be Talent Canal, which has a capacity of 35 to 45 cfs. According to the District, the Talent Canal services approximately 3500-4000 acres. One of the benefits of this alternative would be the reduced chemical requirements needed to remove phosphorous, because most of the water would be reused or land applied downstream. This alternative would mitigate concerns about near field impacts to aquatic habitat, and would reduce the thermal load requirements to the extent that the effluent is reused downstream. On October 5, 2010, representatives from Keller Associates and the City met with TID board members to further discuss this altemative. The following concems would need to be addressed before approval could be obtained for this option: . Real and Perceived Concems of Receiving Effluent - The TID currently does not receive any treated effluent. The district has a number of patrons who have already expressed deep concems about receiving Ashland's effluent. nRAFT CITY OF ASHLAND Page 4 _ COMPREHENSIVE SANITARY SEWER MASTER PLAN .. ~~L.~ . Not Wanting Any Additional Chemicals - downstream farmers have already fought with the district to eliminate other chemical additives for moss control in the district's canals. This concern is heightened by the number of organic farmers. . Approval of Patrons - Because of the controversial nature of this alternative, the board indicated that they would want their patrons to weigh in on the matter, possibly even having a vote of the patrons. Educating the public, addressing their concerns, and obtaining approval at this time would require a great deal of effort with an uncertain outcome. This would also require many months to do. . Removal of flow from Ashland Creek. ODFW has expressed a desire to keep as much flow in Ashland and Bear Creek as possible. There may also be other downstream water right impacts that would need to be addressed by removing discharge. . Other Potential Additional Regulatory Requirements . Additional Maintenance Requirements: o The district's water chemistry is very sensitive to temperature. Even a small increase in temperature or phosphorous is believed to increase the potential for moss growth in their system. o Receiving water during the shoulder seasons - particularly October and November - would adversely affect district operational practices. The City would need to plan on being able to store their effluent during these periods. o Additional fish screening may be required by DEQ. If these screens are required at outfalls, this could result in more maintenance to the district. In addition to needing to address the above concerns, this option would also require that Ashland quantify and then mitigate excess thermal loads corresponding to the portion of flow that is not reused downstream. Given the number of issues and potential road blocks, Keller Associates recommends that this altemative not be pursued at this time. However, it may be that in the future as public perception changes and if drought conditions make the water resources more valuable, it may be beneficial to reevaluate this alternative. 10.4 OPTIONS FOR CONTINUED DISCHARGE TO ASHLAND/BEAR CREEK 10.4.1 Option 4: Cooling Tower I Heat Exchanger I Chiller Background . A cooling tower could be used to reduce the temperature of the effluent through evaporation to reduce the effluent temperature. The primary benefit of the cooling tower alternative is it addresses the temperature requirements without concern for off-site improvements, water rights, potential reduced flows in the stream, or potential compliance schedules. However, this alternative would be an energy-consuming option because the effluent would have to be pumped to the top of the cooling tower and a large fan would be operated continuously. This option was determined to be a viable alternative by Carollo in an evaluation of disposal alternatives completed in 2009 [2]. However, as noted in the Carollo report, a cooling tower nRAIT CITY OF ASHLAND Poge 5 February 20] 1 COMPREHENSIVE SANITARY SEWER MASTER PLAN KELLER eaaoai.C88 could not meet the limits all the time and a chiller would have to be added to reduce the temperature of the effluent to meet the limits during some days. In a cooling tower, air is simultaneously drawn up through the tower in the opposite direction from the water flow. A small portion of the water is evaporated, which removes the heat from the rest of the water. Warm, moist air is discharged to the atmosphere and cooled plant effluent is discharged to the creek. There are two types of cooling towers that would be considered for Ashland: open loop and closed loop, both using plastic media. In the open loop design, the plant effluent would be pumped to the water distribution system at the top of the cooling tower for distribution evenly across the top of the media. In the closed loop design, the plant water is kept separate from the cooling water. The advantage to the closed loop system is that the cooling water is separate from the wastewater, and anti-scaling chemicals could be added to prevent scaling in the tower without affecting the effluent water quality. . There are two types of closed loop designs. In one, the plant effluent would be pumped through coiled tubes from the top of the cooling tower to the bottom of the cooling tower. Cooling water would be pumped to the water distribution system at the top of the cooling tower for distribution evenly across the top of the media. In the second design, the layout is the same as the first except that the cooling water is put through a plate heat exchanger to further cool the cooling water. For larger systems, like that needed for Ashland, this closed loop option is less expensive. The cooling tower would not have to be operated year-round. Its months of operation would be spring to fall. Effluent temperature limits are a daily maximum of 13 oC from October 15 to May 15, and a daily maximum of 18 oC from May 16 to October 14. The effluent temperature regulations allow for exceedence of the effluent limits when the daily maximum temperature exceeds the 90th percentile of the last ten years of the maximum daily temperature 7 -day average. Based on the last 10 years of temperature data from the Medford Airport (closest weather station to Ashland), the 90th percentile maximum daily temperature is 93.3 OF. When the cooling tower cannot meet the effluent limit, a chiller would also need to be used to reduce the temperature of the effluent lower than can be done by evaporation alone. A chiller uses condensers and electrical energy to obtain the additional cooling required similar to a refrigerator. The Oregon Administrative Rules (OAR) provide some relief for meeting the temperature limits with an air temperature exclusion (34041-0028(12)(c)) and a low receiving stream flow exclusion (340-41-0028(12)(d)). The air temperature exclusion provides that effluent temperatures that exceed the limit are not considered violations when "the daily maximum air temperature exceeds the 90th percentile value of annual maximum seven-day average maximum air temperatures calculated using at least 10 years of air temperature data.' Analysis Continuous Discharae. A cooling tower can continuously cool the effluent wastewater to approximately 50F above the atmospheric wet bulb temperature. During each day the wet bulb temperature increases and decreases with the air temperature. The historical climate data for the Medford airport provided daily minimum, maximum, and average wet bulb nRAFT CITY OF ASHLAND Poge 6 February 201 1 COMPREHENSIVE SANITARY SEWER MASTER PLAN KELLER ___Bee. temperature. Using this historical climate data from January 1, 1999 to August 30, 2010, the plant effluent temperatures can be calculated for the minimum, maximum, and mean wet bulb temperatures. Plots showing the estimated cooled WWTP effluent temperature at the mean, minimum and maximum wet bulb temperatures, respectively, are shown in Charts 10.1, 10.2, and 10.3. The mean wet bulb temperature graph is based on the average effluent temperature, while the maximum wet bulb temperature graph shows the maximum daily effluent temperature, and the minimum wet bulb temperature graph shows the lowest daily effluent temperature achievable using a cooling tower. These charts show that, using only a cooling tower and continuous discharge, there would have been a significant number of temperature violations over the last 11 years. When the temperature exclusion discussed above is considered, there still would have been more the 40 violations over the last 11 years. Chart 10.1 - Calculated WWTP Effluent Temperature at the Mean Wet Bulb 5.00 Melin Wet Bulb Tmnpclllturo 25.00 20.00 o '15.00 110.00 i 0.00 3/11/1997 7/2411998 121811999 ....1912001 91112002 1114J2004 512812005 101101200 2/22/2008 71612009 11/181201 41112012 . 0 ~ Temperature nRAn CITYOFASHLAND Page 7 February 2011 ~ - ~- -" - < COMPREHENSIVE SANITARY SEWER MASTER PLAN KELLER 8AOCi.~ Chart 10.2 - Calculated WWTP Effluent Temperature at the Minimum Wet Bulb Temperature 25.00 20.00 15.00 } 1000 i i 5.00 0.00 3111 1997 7124/1 -5.00 -10.00 -Minimum Wet Bulb Temperature Emuent limn -15.00 -20.00 ""'" Chart 10.3 - Calculated WWTP Effluent Temperature at the Maximum Wet Bulb Temperature 30.00 25.00 20.00 I ".00 I i 10.00 5.00 0.00 3111 997 7124/1998 12J611999 411912001 9/112002 11/181201 4/1 012 o -5.00 -10.00 -15.00 - Max Wet Bulb Temperah.n& - -- Effluent Limit -20.00 ""'" nRAFT Page 8 CITY OF ASHLAND February 20 I ] COMPREHENSIVE SANITARY SEWER MASTER PLAN KELLER ..88Om.tea Storaae. In order to meet the effluent temperature limits with a cooling tower, Keller Associates looked at using storage to cool plant effluent only during the night when the air temperatures are lower. A discharge period of 12-hour period was assumed. The storage would be sized for half the peak flow between April and October, as some of the potential violations for continuous treatment are in the shoulder periods. The estimated peak daily flow during this period'is 5.5 mgd, and thus the storage tank would be sized at approximately 3.0 million gallons. The Oregon Department of Fish and Wildlife (ODFW) has indicated that they would want the City. to continue to provide continuous discharge to maintain a more uniform flows in the creeks. This would require the City to store the cooling tower effluent and discharge continuously from this tank. For planning purposes the effluent tank was also assumed to be 3.0 million gallons. Since the cooling tower effluent would be stored, the final effluent temperature would be between the effluent at the mean and minimum wet bulb temperatures shown in Charts 10-1 and 10-2. Thus, there would still be several violations of the effluent temperature limit. The cooling tower may not meet the DEQ effluent temperature requirements all the time without additional treatment utilizing chillers to lower the effluent temperature during hot nighttime weather periods. Chiller. In order to prevent any discharge temperature violations, a chiller would be needed to reduce the effluent water temperature further. A chiller would use condensers and electrical energy to obtain. the cooling required. Based on the climate data analysis, the chiller may be required to reduce the effluent a further 3 DC at times. To reduce the size of the chiller, it would be installed in the effluent line from the final storage tank and thus be sized for 5.5 mgd or 3800 gpm. The preliminary sizing of the chiller is 1,500 tons. The chiller would also need to be installed in a building. Cooling Tower and Chiller Alternative A cooling towerlchiller alternative that would allow the City to meet the effluent temperature limits at all times would consist of the following components: . Cooling tower inlet storage, sized to hold 12 hours of plant effluent flow from 10 AM to 10 PM during the period April 1 to October 30. The tank would hold 3.0 million gallons (50% of the peak dry weather day in 2030). For budgeting purposes, Keller Associates assumed the storage would be a concrete tank (high range) or a lined pond (low range). . Pumps, sized to pump the daily flow from the storage tank to the cooling tower (assumes permeate pumps or filter pumps can feed the tower). . Cooling tower, closed loop type, sized for the twice the peak dry weather day flow (7,600 gpm) in order to pump the peak day during the 12 coolest hours of the day. For budgeting purposes, Keller Associates assumed that the cooling tower would include a plate heat exchanger for the cooling water and non-<:hemical water treatment system for the cooling water to prevent scaling. . Cooling tower effluent storage, sized at 3.0 million gallons; assume continuous gravity discharge at the plant influent flow rate via a motor-contro,"ed valve. For budgeting nRAI'T CITY OF ASHLAND Page 9 _ COMPREHENSIVE SANITARY SEWER MASTER PLAN t.1l:l. KELLER ~ eaaoai.cea purposes, Keller Associates assumed the storage would be a concrete tank (high range) or a lagoon (low range). . A 1,500 ton chiller, sized to cool 3,800 gpm 3 DC, in a building (approx. 32 feet by 22 feet and 16 feet high). The estimated capital cost for this option is $ 6,100,000 to $8,100,000, depending on the type of storage. The estimated annual O&M costs for the cooling system are approximately $200,000 (for either storage option). The O&M challenges are: . Scale control in tower and chiller. . Tuming cooling tower system on as temperature limit is approached and off as tower is not needed. . Controlling the pump rates to the tower and chiller and outlet rate from the final effluent equalization tank. . Operating chiller when needed. 10.4.3 Option 5: Trading (Shading) Temperature trading allows for excess thermal loads to be offset by shading (from riparian vegetation) and other approaches that reduce heat loading such. as constructed wetlands, flood plain restoration, and restoration of cold water refugia. In recent years, the temperature . trading program has been developed more fully in the State of Oregon. With project protocols, verifications, and reporting procedures in place and accepted by DEQ, trading is now a viable solution for cities facing new thermal load limits like Ashland. DEQ allows for offsets in the TMDL area to apply both upstream and downstream of the point discharge. While there are few opportunities for trading in Ashland Creek, there are many opportunities to trade along Bear Creek and within the Bear Creek watershed. In evaluating this altemative, a non-profrt organization, The Freshwater Trust, assisted in the analysis. To complete the analysis, The Freshwater Trust coordinated with and received and field verified data from DEQ's Heat Source models for Bear Creek to determine the extent of opportunities for riparian revegetation with native species to create shade and minimize solar loading in the TMDL area. In addition to using DEQ data for the analysis, The Freshwater Trust worked closely with DEQ technical staff to confirm its analysis procedures. The heat source data for Bear Creek was divided into three equal interval classes: LOW, MID and HIGH, based on the difference between existing shade cover and potential shade cover. Areas with the highest potential for improvements and shade credits are designated as HIGH. The lengths and potential solar load reductions for these reaches are summarized in Table 10.1. The location of LOW, MID, and HIGH Bear Creek river stretches is further illustrated in Chart 10A. nRA>T CITY OF ASHLAND Page 10 February 2011 COMPREHENSIVE SANITARY SEWER MASTER PLAN KELLER eaaoalBtae Table 10.1 Bear Creek Heat Source Analysis Results' Average of 25% Potential per mile kcaVda 3 257 325 6616843 10141,007 , 6,795,376 TOTALS wei hied aye e 27.15 'Information provided by The Fresh Water Trust # Miles by Potential Cat 0 5.16 16.65 5.34 % Miles by Potential Cat 19% 61% 20% 100% 164 494 510 Chart 10.4 Bear Creek - Potential Solar Load Reduction by River Mile PoI.ntJalSo~r load Rlduction . I ..;- , 2 -h 4, I ~ 6 , <::" I ... I I 10. - w 12 ~" t.. -, , 7::14 .. ..- j.. ~, . ~ 16. T - 1_- 11. , 2J , : 22 24 I_~ 26 -.::; I , 5.0 10.Q, 15.0 20.0 IMIion,s of Kca~milelday ste-mTotal5 ,/l(rfl'lio ~ OwneD ~ Pat~ Points 'i low Poteontiilll Tolls! lmillian ICcal) Md Potentlat-Tctill million "cal ; Total 5 swm Potentl.1 _ The Heat Source analysis showed that revegetation projects on Bear Creek will produce between 3,257,325 and 10,141,007 kcaVday per mile with a weighted average of approximately 6,800,000 kcalslday per mile. Using this weighted average, to meet the projected 2030 excess heat load of 53,000,000 kcaVday, an estimated 7.8 miles of riparian revegetation will be needed. The actual length of shading requirements will depend on the existing conditions for the reaches targeted. nRA~ CITY OF ASHLAND Page J 1 _ COMPREHENSIVE SANITARY SEWER MASTER PLAN . !,<~.~ With over 27 miles of riparian area, over 80% of which are in the mid to high-potential range, the data show there are sufficient revegetation opportunities along Bear Creek to meet reduction targets. For the purpose of this analysis, two conservative assumptions were made: first, the Solar Load Change actually projected is reduced by half to account for planting along only one side of the stream bank; and second, DEQ requires that the load be reduced by half again to cover risk factors of temporal loss and uncertainty. Under this alternative, the temperature of the effluent is not cooled prior to discharge. This creates the potential for near field (local) impacts to aquatic habitat that must be accounted for. To address these concerns, Keller Associates has worked closed with regulatory agencies, the City, and other stakeholders to develop a plan that will work. This includes the following improvements intended to address near field concerns: . Relocating the outfall from Ashland Creek to Bear Creek. Keller Associates proposes that this be completed via an open channel arrangement that would convey treated wastewater to Bear Creek via a side bank discharge. Based on modeling completed by DEQ, this single improvement would alleviate all near field concerns with the exception of potential migration concerns in September (there have been a few days in the last fIVe years that would require the effluent temperature to be lowered from 23.5C to 22.3C in September). Using an open channel conveyance could further cool the effluent via shading and interaction with shallow ground water. . Modifying the existing wetland pond. While this improvement may not be required to meet DEQ thermal load improvements, the wetlands could further serve to cool the effluent and improve aquatic habitat. The existing pond is too deep to encourage growth of vegetation and additional shallow groundwater interaction that would further cool the water. Creating a shallower wetland could support growth of wetland vegetation that would further cool the effluent. Additionally, ODFW has expressed a desire for off channel habitat which could be provided through properly designed wetlands. The final size of the wetlands may need to be expanded depending on a number of issues yet to be determined such as hyporheic action, shading in the channel and wetlands, and other shading activities along Bear Creek upstream of the outfall, and additional flow and temperature data. . Other improvements that could be added into this alternative to improve conditions for fish include: 1) removing the current outfall structure which allows fish to enter the effluent pipeline of the WWTP (and possibly be trapped), 2) constructing a fish barrier (i.e. waterfall) in the new discharge channel from the WWTP..3) modifying the existing pond by replacing/removing inlet and outlet structures. The Oregon DEQ has expressed support for temperature shading as a means for meeting thermal compliance at WWTPs. Other benefits of this alternative include: . Low capital and O&M costs. On-going power costs associated with other alternatives . such as cooling towers can be avoided. Costs are also spread out over the duration of the project. . Flows remain in the stream for improved conditions for aquatic habitat during low flow periods. . Shading along the creek also improves aquatic habitat. . Other aesthetic and environmental benefits associated with trees. nRAn- CITY OF ASHLAND Page 12 _ COMPREHENSIVE SANITARY SEWER MASTER PLAN I2l. KELLER W eaaocda&a8 An estimated cost for this alternative was prepared with input from The Freshwater Trust, and has an estimated net present value of approximately $2.7 million. Actual costs could vary depending on the final sections of river that are targeted for shading and the final scope of improvements targeted for the outlet relocation and wetlands work near the treatment plant. 10.4.4 Option 6: Blending / Flow Augmentation The concept of blending or flow augmentation involves releasing cold water upstream of the Ashland WWTP. The source of this water would be either flow from TID (ideally from lower depths of the Emigrant Dam) or from Ashland Creek. The City of Ashland is currently in the process of permanently securing an additional 600 ac-ft of additional water rights formerly belonging to the City of Talent. The purpose of this right would be to augment existing flows in Ashland Creek and/or provide additional potable water supply. One of the benefits of this alternative is that increased stream flows could improve stream conditions in Ashland and Bear Creeks. For flow augmentation to work, the water quality and temperature conditions of the supplemental water need to be considered. This study does not include a comprehensive evaluation of these parameters. However, the City did install a temperature monitoring device in the TID system for about a week in August of 2010. Based on this temperature data, flow in the TID system already exceeded the target temperature thermal limits (180C) and therefore would not be able to cool Ashland's effluent to levels that met the TMDL standard. Additionally, it should be noted that if flow augmentation were used, that DEQ has indicated that they want to see information on presence of parameters in the source water for which Ashland and Bear Creeks are water quality limited (see 1992 and 2007 TMDLs) and additional parameters may be needed depending on origin of source water. Given the need for additional potable water rights and the preference of the City to use Ashland Creek water over TID supplied water, it is unlikely that if additional Ashland Creek water rights could be s'upplied, that these rights would be used for flow augmentation during critical low flow conditions when they would be needed the most for flow augmentation. While flow augmentation may help mitigate thermal impacts during certain times of the year, Keller Associates does not recommend this as a sole solution to address excess thermal loads. 10.4.5 Option 7: Hyporheic (shallow groundwater mixing) The hyporheic zone is the region where shallow ground water interacts with the surface water in a stream or river. Depending on numerous conditions (e.g., channel geometry, soil characteristics, diurnal variations, season, etc.), the hyporheic exchange can act as a buffer for river temperatures and/or as a mechanism to coollwarm river temperatures. Using a hyporheic discharge was previously recommended for future study as a disposal option for temperature control. Implementing this process can take several forms, which can be divided into either a direct or indirect injection into the water table. Each application must satisfy the following requirements [5]: 1. Definition and maintenance of a Waste-Management Area (WMA), which defines the confines of the infiltrate influence (Chart 10.5). The WMA must be situated so that the infiltrate remains within the confines of the property and does not affect existing wellS. nRA~ CITY OF ASHLAND Page 13 _ COMPREHENSIVE SANITARY SEWER MASTER PLAN .!,<~.~ Also, it needs to be shown that the infiltration will not contaminate the groundwater/aquifer. 2. Site/soil suitability, primarily that the hydrology of the site would permit the injection of the proposed quantity of effluent. 3. Public acceptance of the practice. Chart 10.5 - Waste-Management Area [5] y= Limit Groundwakr/Smface Wattf Interbtt "DiIIbs..-" F'ig1In 1 Piau \'Iow Scbomatic IDdlrKt D1"'bargo Modol To SnrfDU \Vatf'r Shop< md dowu st=m limit ofll1o Mixing:zo..IO 1>< _ by tile Mixing Modrl md st=m dl'o=.:$. Notes: I. At L. provick grouncIwattt \"OImDt. \~lot:dy and C'OOttIltratioa ottcy wattr quality pa:nmtttrs for mixing zone modd. These typically will 1>< _ bas<d ..._... modeIiDg. 2. L fimctions as a.snrbce wattf d:if't'bser. 3. EtOumt ~ in the Wask-~ Aro. em. br in gronwtwa1rf. hypolbric wakr. or both. 4. IimiIs ofWasro-Mzug..".", A=... d.~ by_~ of tile _ in grooo<Iw>.... hypodlric ...... en both. . Symbols: E}j Verification monitoring \\-eD locatioD (i.e.. dmtcttan monito1'lng \\'t:U) ex COI1Ceotr.Ition of try ".ok:w.ta dDumt ............tus.. Cy Concmtmion of try efIbxnt ~ in grouncIwattt Of hyporll:ric wattr at trmsitioo. to surface W2tft" for mixing zom: analysis. t_g. (uw.~.tioD COt di1fusn- at L. L l.atgthofW..~^,"."'=ri\-ingwmrbody. While the effluent temperature could conceivably be reduced through dispersion and conduction with ground water, this relationship cannot be adequately desc~bed without sufficient site data. A rough, preliminary design can be completed using semi-conservative values, which can be used as a basis to formulate site parameter investigations. nRAFT CITY OF ASHLAND Page J 4 _ COMPREHENSIVE SANITARY SEWER MASTER PLAN . ~~.~ A planning level evaluation of this alternative was completed for Ashland. This section includes summary information. For more detail refer to Appendix XX. A preliminary evaluation of the Imperatrice property was considered. However, due to the low permeability of the Imperatice property's soil, potentially shallow soil depth, significant slope, and incOmplete WMA control, the site would likely not be well suited for effluent infiltration and hyporheic exchange. The hyporheic option could be implemented at other sites in close proximity, assuming property acquisition was a possibility. Soil maps from the National Wetland Inventory indicate substantial soil type differences in the valley, namely the presence of sandy characteristics in some areas. Sandy soils typically have a higher permeability rate, with typical values ranging from 0.13 to 12.96 in hr" for clayey sand. Over this range of values, the foot print for each MGD of effluent would be between 780 and 8 acres (assuming 15 ft of head and 300 m spacing between the river and the infiltration basin). These areas only include that needed for the WMA; due to plot dimensions, considerable additional property would likely be purchased as well. If this option were pursued, the following phased approach should be completed in stages, obtaining more and more detailed estimates of the site characteristics, while minimizing potentially unwarranted expenditures. Initial sample planning should be based on the aforementioned design, first assessing if the City owns property that could be isolated enough to satisfy the groundwater protection requirements while providing an adequate footprint for the above design. Behind each stage is a progressively more accurate model of . the groundlhyporheic water flow and the river mixing, which determines the viability of the design and directs subsequent investigations. We would recommend the following approach, each phase of which could be conducted in stages: Phase. 1 - Initial Site Assessment and Monitoring Well Installations A preliminary assessment of the sites suitability for this approach can be completed by installing ground water monitoring wells throughout the site, as directed by the preliminary design. Placing the wells near the creek's edge as well as toward the site's boundaries will allow the wells to be used in the future for compliance testing, assuming the site is suitable. Recording soil properties and water levels in the drilling processes of the wells should provide a rough approximation of the site's geology and groundlhyporheic water state. These parameters could be used to estimate the site's infiltration capacity and subsurface conductivity. With these estimates, a rough design of the infiltration basins could be completed, balancing the need to minimize the waste-management area while maximizing the distance between the infiltration basin and the creek. Phase 2 - Single and Multiple Well Aquifer Tests, Mixing Model Precursors Assuming that the preliminary design completed using the estimated site parameters were viable, a more refined estimate of the site hydrology should be completed. To accomplish this task, wells should be drilled according to the predicted design, with locations in the infiltration area(s). Single well aquifer tests should then be performed to obtain actual conductivity information for the site, using the previously installed monitoring wells to observe the site's response. Using the results from these tests, the actual distribution of site conductivities can be more accurately estimated. These values can then be used to refine the previously developed model to reassess the site's viability. Tracer studies could also be used to determine ground water flow and dispersion. nRAFT CITY OF ASHLAND Page 15 _ COMPREHENSIVE SANITARY SEWER MASTER PLAN .. ~~.~ The Oregon DEQ requires a mixing model analysis to be performed to determine the impact of the hyporheic exchange on the creek temperature profile, to estimate the mixing effects. To approximate these effects, the creek profile should be approximated over the range of available property, determining cross section profiles, depth, and velocity. An estimate of the hyporheic mixing capacity would also be of help. As indicated by the research of Lancaster et al.[6], if properly distanced from the creek, the injected heat should not substantially impact the creek temperature. Phase 3 -Long Term Monitoring Provided that the refined design was still viable, the behavior of the groundwater should be observed to determine seasonal variation and response to rainfall and creek flows. These observations would provide additional insight into the actual response of the site to real infiltration, allowing further calibration of the model and verification of the groundwater flow direction and velocity. Phase 4 - Scaled Infiltration Test Using a full scale design based on the estimated infiltration capacity and ground water response as a guide, a large scale infiltration test would provide a final model verification prior to full construction. Using this approach, the capital investment required for an accurate model (which is expected for permitting [5] could be expended in stages, each of which would. allow for the overall evaluation of the process, to determine if further investment is warranted. Other Hyporehic Considerations It should be noted that hyporehic activity can also occur through leaky wetlands. Thus some hyporehic activity could occur if the City's existing effluent outfall were relocated from Ashland Creek to Bear Creek via a channel and possible downstream wetlands. 10.5 SUMMARY AND RECOMMENDATIONS Table 10.2 on the following page summarizes the disposal alternatives, benefits, drawbacks, and costs. Based on the available information, Keller Associates recommends that the City proceed with Option 4, Trading (Shading). Concurrent to pursuing Option 4, Keller Associates recommends that the City pursue recycling as needed to address future potable water supply needs. nRAI'T CITY OF ASHLAND Page 16 February 2011 COMPREHENSIVE SANITARY SEWER MASTER PLAN KELLER euoai.C88 Table 10.2 - Ashland WW Disposal Opflon Comparison Chart Not DescriptIon I Capital Annual Present - Option _ PrSlJect Ek.!"ents B~~lts - Drawbacks - - Cost Cost V,!II,l~mments lA Maximum Irrigate 433 acres Beneficial use of water. High Cost. $10.8 M $(58,000) $13.4M Savings Reuse on with treated Existing water right could lower stream flows. assume that Imperatrice effluent. be used to augment membranes Property Pipeline to site. potable water supply. are not used. 138-166 MG Potential for membrane storage. and chemical savinp. Shoulder season Mitigate concerns of storage required .future- more stringent I winter regulations. dischare:e. 18 Partial Reuse lower cost does Similar to Option 1A. High Cost. $5.3- $35,000 $5.8- For lower on includes Improvement could be Introduces complexities in 8.9M 9.4M cost range, Imperatrice minimum completed later if Option monitoring and wastewater need to add Property - storage. 3 or 4 is pursued. management. cost of 424 ac*ft/yr Higher cost Higher o&M costs than Option 3 or 4 assumes more Option lA. to address storage, and Reduced stream flows rooting periods of no available for aquatic habitat. requirement discharge. 2 Discharge to Pipeline to Mitigate "near field" Not a standalone solution Not Not Not liD Talent Canal. concerns. still need to offset excess Evaluated Evaluated Evaluated Reduction in chemical thermal loads. costs. High opposition from downstream users antidpated. District concerns about chemicals. Storage for shoulder seasons likely required. Schedule and approval outside of Cltv ~ntrol. 3 Cooling Tower Mechanical Addresses temperature Olillers required for hottest $6.1- $200,000 $8.6- Cost range cooling tower. concerns. periods. 8.1M 11.6M reflects use Storage facilities. Allows continued Upstream I downstream of ponds discharge. storage also required for versus Maximum control In night~time operation concrete terms of compliance storage schedule. reservoirs 4 Trading B miles of lowest cost alternative. Some uncertainty- $3,400,000 spread out $2.7M (Shading) shading. Allows continued participating property over 20+ years Channel to Bear discharge. owners to be identified; Creek. Improved aquatic habitat migration blockage Constructed and other environmental evaluation to be completed. wetland pond. benefits. Potential minor additional local coolinll reouired. 5 Blending I Blend additional Additional stream flow. Cannot meet temperature Not Not Not Not a viable Flow water discharges targets by itself. Evaluated Evaluated Evaluated alternative. Augmentation from Ashland Uses water that could be Creek or TlD. used for potable water usage. Additional water quality testing may show additional water quality concerns. 6 Hyporheic Subsurface Low operations costs. Difficulty in locating site with Not Not Not (shallow disPosal of Simple technology. suitable soils. Evaluated Evaluated Evaluated groundwater) treated Significant additional effort wastewater to required to determine shallow ground feasibility. water. Potential large land requirement. nRAH CITY OF ASHLAND Page 17 February 2011 COMPREHENSIVE SANITARY SEWER MASTER PLAN KELLER .1I8OCd.~ References 1. John Gasik: City of Ashland Excess Thermal Load Umits, WQ File No. 3780, ODEQ Memorandum, February 16, 2011. 2. Carollo Engineens: City of Ashland Updafe to WWTP Facilities Plan and Permitting Evaluation, Temperature Management and Wafer Recycling, November 2009. 3. Carollo Engineens: City of Ashland Wastewater Treatment Plant Upgrade Project, Project B - Offsite Facilities Predesign Report, November 1997. 4. Carollo Engineens: City of Ashland Water Conservation & Reuse stuc:/y (WCRS) & Comprehensive Water Master Plan (CWMP), Technical Memorandum No. 7 - Recycled Water Regulations, September 2010. 5. Oregon DEQ (2007). Disposal of Municipal Wastewater Treatment Plant Effluent by Indirect Discharge to Surface Water via Groundwater or Hyporl1eic Water. Internal Management Directive.state of Oregon Department of Environmental QualityPortJand. 2007. 6. Lancaster, S., Haggerty, R., Gregory, S., Farthing, K.T., and Biorn-Hansen, S. Investigation of the Temperature Impact of Hyporl1eic Flow: Using Groundwater and Heat Flow Modeling and GIS Analyses to Evaluate Temperature Mitigation Strategies on the Willamelte River, Oregon. Final Report to Oregon Dept. Environmental Quality.Oregon State Univensity, Corvallis. 2005. nRAFT CITY OF ASHLAND Page 18 ~ r4 m:m State of Oregon Department of Environmental Quality OREGON DEPARTMENT OF ENVIRONMENTAL QUALITY Memorandum WESTERN REGION - MEDFORD To: Ashland STP File Date: February 16,2011 From: Jonathan Gasik, MS, PE, Senior Engineer Western Region Medford Office Subject: City of Ashland Excess Thermal Load Limits WQ File No. 3780 BACKGROUND The Ashland WWTF discharges into Ashland Creek .approximat~ly 1600 ft (490'1JI) fr9m its confluence with Bear Creek. Although Ashland Cieek'isnot currently on the 2004/2006 303(d) list for temperature, a review of temperature logger datilJrom Ashland Creek abov'e the WWTF discharge point indicates that the stream should be listed yeir,cround for an exceedance of the applicable temperature criteria (Table] 6),,11) July 2007, DEQ.finalized the Bear Creek Watershed TMDL. The Bear Creek TMDLailocates the Ashland WWTF a O,IOC increase (HUA) above the applicable criterion in A~hiaild <;:ieek as well a~'at the point of maximum impact. The TMDL also states that "As part of the NPDES' permit renewal process, the city of Ashland may wish to compute daily or monthly,theritlal wa~te load allocations based on the applicable standard, actual rece'iyjng water flows,: imd actual WWTF discharges," , . l .. In April 2008, DEQ i~s!Jed the Te!Jiperature Stanaard Implementation Internal Management Directive (IMD). This memo will 'use the methods'described in the IMD to calculate Excess , ,. ~, , , Thermal Loads based on the 2008 Bear. Creek TMDL, and evaluate whether the Ashland WWTF can immediately comply with the' ne~ Exf~~~,Th~rmal Load Limits. I .. ". . , . '. ~ EXCESS THERMAL LOAD LIMits For point' squrces, TMDL wasieload ailocations (WLAs) are implemented through effluent limits in NPDES p'ermits. Thermal WLAs are expressed in permits as thermal load limits, Because the TMDL is based on aHuman.lJse Allowance above the applicable criterion, the thermal load limit is known as an' excess tllermalload(ETL), As mentioned above, the TMDL allows for the thermal limits to be based'on various river flows. Therefore, DEQ may calculate ETL limits based on critical case low-flows or actual measured flows, As described in the IMD and the TMDL, the thermal WLA can be converted directly to ETLs using the following equation: Thermal WLA = HUA · (Qps + Qr) · c Where, HUA = Human Use Allowance Qps = Point Source Effluent Flow (cfs) Qr = upstream river flow (cfs) C = conversion factor (2,446,665 kcal's/ oCft3'day) City of Ashland Excess Thermal Load Limits February ]6,2011 Page 2 of 13 Criticallow-Ilow based limit: A conservative approach would be to use a critical low river flows (Qr) to calculate the WLA and apply this WLA directly as an ETL limit for each water quality limited season; summer (May 16 - Oct 14) and spawning (Oct 15 - May 15), The critical low flow is the lowest seven day average that has a 10 year recurrence (7Q 1 0). This approach has the advantages of simplicity and that no additional information in needed, However, it may be overly conservative and may result in an unnecessarily restrictive ETL limit. For Ashland Creek, the critical low-flow based ETL limits are as follows: Month Applicable Dry Receiving Hnman WLA Effluent Criterion Weather Water Use 2 Temp (MW) 0 Design 7QlO Allowance Limit C HWLA Flows I 0 0 CFS Q CHUA CT CFS Qps R WLA May 16- 18C 3.65 I ~ O,IC :.055 18.13 Oct 14 . . Oct 15~ 13C 3.65 3: : O.IC .079 13.18 May 15 " - , . The TMDL WLAs are in megawatts, but the Temperature]MD directs staff to calculate the ETL limits in kilocalories. Therefore, the critical low-flow based ETL limits are 788 Kcal and 1132 Kcal, for the summer and spawning season,s respec~ively. ':, . Actual Stream Flow-based Limit: The ETL'limit may.also be based on the actual stream flow. ,.. ".,' In this case, Ashland would need to collect and report stream' flow data. The ETL limit would be calculated by direct conv,ersion .oft,he WLA usin'g'the equations above: Excess Thennal Load (ETLj, (Year Roun(!) _ , Limitations Shall not exceed a rolling seven-day average based on the . - . .equation: -!O:n: =: (Qps + Qr) * 0.245 million kcalosf oCoft3oday Parameter " . Where, Qps = Effluent Flow (cfs) r= u stream river flow cfs EXCESS THERMAL LOAD'(ETL) The ETL calculated using th7: following equation: Thermal Load ":': 9Ps* t> Pc Where, Qps = point source effluent flow t>T = difference between the effiuent temperature and the applicable criterion (Te- T criterion) C = unit conversion factor (2,446,665 kcal'sl oCft3.day) As discussed above, the applicable criterion is either the biologically-based numeric criteria or the natural thermal potential (NTP), whichever is higher. Ashland Creek was not Heat Source modeled by DEQ as part of the temperature TMDL. In the absence of modeling the temperature criteria that applies to Ashland Creek is 13.0oC (55.40F) October] 5 through May 15; 18.0oC City of Ashland Excess Thermal Load Limits February ]6,20] I ' Page 3 of]3 (64.40F) May 16 through October ]4 (Biologically Based Numeric Criteria OAR 340-0041- 0028). The ETL is calculated as a weekly average by using the seven day average of the effluent flow and the seven day average of the daily maximum effluent temperatures. The City of Ashland collects daily effluent flows, effluent temperatures, and receiving stream (Ashland Creek) flows. The following table shows a comparison of the maximum ETLs with the critical case based ETL limits: Month Critical Low flow ETL Maxim.um ETL Limit May]6-0ct 788 Kcal 46,000,000.kcal ]4 Oct 15 - May I ] 32 Kcal 45,000,000 kca] . 15 , . As mentioned above, the TMDL allows for the thermal limits to be based on various river flows, The following charts use data from Ashland WWTP's discharge monitoring repol1s. from 2009 to show the flow-based ETL limit and the ETL. . Summer Thermal Limits 50 45 40 ~ 35 ." ~ 30 ~ 25 c: ~ 20 :E 15 10 5 o -Ell -------- - - Ell limit ~ m m m m m m m m m m m m m m m m m m ~ 0 0 0 0 0 0 0 0 000 0 0 0 0 0 0 0 c ~ ~ 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 ......................---------..............---- ~ N ~ 0 m ~ ~ w q ~ N ~ m 00 ~ w ~ ~ N_~NN_~N_~NM_rlN-rlN _~___~__ro___m__o__ ~ ~ ~ w ~ ~ 00 00 00 m m rl 0 0 ~ ~ City of Ashland Excess Thermal Load Limits February 16,2011 Page 4 of 13 Spawning Season Thermal Limits SO 40 > 30 '" ." 20 ..... .. u 10 ... " ~ 0 ~ -10 -20 -30 -Ell - - Ell limit vmmmmmmmmmmmmmmmmmmm ~ooaoaoooooooooooooo 00000000000000000000 NNNNNNNNNNNNNNNNNNN ........................--.......................----------- ~NNM~~rommo~N~~Nm~~~ MN_.-iN_.-iN_N_.-iN_.-iN_.-iN __N__~__~_~__~__N__ .-1M NN mm q UlO.-i..............NN .... .-i..... ......... ,., . As can be seen by the charts above, the current ETL exceeds the ETL limit during both the summer and spawning seasons. '-; '. _ . -::': . Existing Facilities and Strategies for Temperature Managem'ent::,.:, Recognizing that significant thermal reductio~~ w~~ldbe re9,!ired ~y'the Bear Creek TMDL, the City began exploring options i~ ?006 with the' formation Of aiJ'ad hoc committee. The committee's goal was to explor~ options to meei!he proposed thermal limitations with an emphasis on water recyCling. Th'e.€ity continued-to work on options and in November 2009 completed a report whicp il]c1uded'4:strategies, cost e.stimates, non-economic evaluation, and a recommendation. The follo~in.g t~ble i~ a ;mmmartofthe report: - Strateg Strategy Description Capital Present Non-Economic Evaluation y Cost Worth Cost No'. I - Effluent Cooling in ; . $2,500,00 $2,540,00 Proven technology. May need mechanical cooling 0 0 storage ponds for critical towers' : . periods, No.2 No discharge with $1,600,00 $1,630,00 Poor local public perception effluent reuse via 0 0 regarding reuse, TID's discharge to Talent irrigation season does extend Irrigation District Canal into Fall. (TID) No.3 No discharge with $11,700,0 $1 ],750,0 Supplements City water supply. effluent reuse in City 00 00 Poor local public perception identified properly regarding reuse. No.4 Discharge to hyporheic $2,600,00 $2,600,00 Maintains stream flows. water 0 0 Opportunities to improve riparian zone. New strategy, unproven, City of Ashland Excess Thermal Load Limits February 16, 20 I I Page 5 of 13 The report recommended pilot study to further evaluate Strategy No.4 (hyporheic discharge). If this study shows that hyporheic discharge has limited potential to address temperature issues in Ashland Creek, the recommendation is to construct a cooling tower. Regardless, the report recommends that the City continue to work with the TID to identifY opportunities for taking recycled water into the TlD system and using stored water to offset flow impacts of effluent withdrawal. Tbermal Plume Analvsis In addition to the temperature criteria, the mlxmg zone rule contains limitations regarding thermal plumes. In accordance with OAR 340-041-0053(2)(d), temperature mixing zones and thermal effluent limits will be established as necessary to prevent or minimize the following adverse effects on salmon ids: . . . A) Impairment of an active salmonid spawning area where spawiling redds are located or likely to be located. B) Acute impairment or instantaneous lethality: . C) Thermal shock caused by sudden incre~se in water temperature. ,. D) Migration blockage caused by temperature .differential between the"pliJme and the receiving stream. ,- ., . The following chart shows the minimum"maximum, and average effluent temperatures reported on Ashland's Discharge Monitoring Report~' fi'om ' . : - . .,' Ashland STP Effluent Temperature 25 20 u ~ " " tic 15 " o - - 10 5 Jan Feb Mar Apr May Jun Jul Aug 5ep Oct Nov Dee The City of Ashland collected stream temperature data from July 2004 to August 2005. The reported stream temperature exceeded 300C on several days. However, due to the sudden jump in the temperature, these appear to be periods when the temperature sensor was exposed to air, and not the actual water temperature, Excluding these periods from the dataset, the Ashland Creek temperatures are as follows: City of Ashland Excess Thennal Load Limits February] 6, 20] 1 Page 6 of ] 3 Ashland Creek Temperature (7 day average) 25.00 ... .....................................................................1.........1......:......................................... 20.00 - --I' --- ...... , , , ~ 15.00 ,,'" .. .. ~ .. .. o 10.00 5.00 0.00 .,~ .,~ ~.:;j ~v "\'b <<.~ is .,' ~ ~~ ~<i ~.,,,- ,,'" \V .s"- ~ ~ rz} ~ ~'O 'I:?-';:; ~e; <,"'''1 ~ if' C' o e" rz} .-? ~'O ,.:::."'" (..e ~o ()e In previous studies, DEQ estimated the 7Q 10 /low in Ashland Creek at ] cfs. Since that time, the City has collected almost ] 0 years of /low. data. The following table shows the lowest seven day average stream /low, the average STP /low, the average stream temperature, the average STP temperature, and the calculated stream temperature aft.er mixing by 1110nth: Month Lowest seven Average STP . .Average. ' Average STP Stream , ... day averag~<; .,/low (mgd) . UpStream.' Temperature Temperature stream /low . . Temperature after complete (cf;{. . , . . mixing Januarv 1.36 , . 2.49 ',' 4.86 ]3.39 ]1.16 February 1.66 . . " .2.35 . . 5.22 ]3.47 10.88 March : :..... ',0.98 . , 2.27' 7.01 ]5.70 ]3.80 . . April ',1.67 " 2.19 8.64 ]7.0] 14.25 May'. '0:87, ',2.22 ] ].02 ]9.99 18.]7 June -: , 0.87, 2.08 14.83 22.06 20.52 July '. , 1.77- 2.04 18.83 25.40 23.04 August , ].22, , 2.0] 20.5] 25.40 24.02 . . ~ . . September ',. . ~ ].66, 2,02 17.06 23.50 21.27 ., . October <';',l.f4 2.00 ]2.67 21.79 19.33 November ;. 1.13 2.01 8.55 18.36 15.75 December 1.11 2.30 5.25 ]4.74 12.49 Impairment of spawning is prevented or minimized by limiting potential fish exposure to temperatures above ]3 degrees Celsius [OAR 340-041-0053(2)(d)(A)]. The area in the immediate vicinity of the discharge is an active spawning area for winter steel head, summer stee]head, resident trout, and coho salmon. Figure 271 B of OAR 340 Division 4] designates Ash]and Creek as'spawning from October 15 through May 15. City of Ashland Excess Thennal Load Limits February] 6, 20] ] Page 7 of 13 Because Ash]and Creek is so small, there is currently no regulatory mixing zone or ZID assigned to the wastewater treatment plant. The discharge is currently configured so that the discharge transverses the entire stream almost immediately and DEQ is not able to allow any significant dilution in the ZID. Therefore, because the effluent exceeds 130C during all of the spawning period, the effluent has the potential to impair spawning. Additionally, the .tab]e and charts above show that the effluent causes entire stream to exceed the 130C during March, April, May, October, November, and December. Active Acute impairment or instantaneous lethality is prevented or minimized by limiting potential fish exposure to temperatures of 320C or more to less. than two seconds. Acute impairment requirements are met because all of the City's effl,uent temperature data was below this temperature. The highest effluent temperature recorded'is26.30 C on 7/27/2003. .. . Thermal shock is prevented or minimized by limiting pD,ten.tiill, fish exposure to temperatures of 250C or more to less than 5 percent of the cross section. of the water body, ,unl.ess the upstream temperature is above 230C. Migration blockage is prevented or minimized by limiting potential fish exposure to temperatures of 2] oC or more to.le);"s.than 25 'percent of the cross'section of the water body, unless the upstream temperature is above'Zfoc. ,-:. " . ",.. J. ',.' "," The figure above shows that ,the seven day average stream~.tell)perature does not exceed 230C. However, there are periods in July and August. that are above.21 ~.c. The table below shows the calculated stream temperatures based on the Iciwest.7 day average stream /low, the average STP flow, the highest 7 day average STP temperature':an<J.!he aver~g~ stream temperature after mixing with 5 percent and 25 percent of the ;stream.'fl6w: ;P.eriods' when the stream temperature was 21 oC or greater were 5xcluded from the 25 ,~!lrcent calc~laiion: " Month Stream,Temp Stream Temp after'mixing. after mixing " with 5% . with.25% January 13:24 12.69' . . February:- 13:29 :', . : 12.62 March' ]5.58 15.13' Abril" ;.: ]6.81 , 16.10 May 19.87 19.45 June , 21.96 21.60 July -25.22 23.38 August 25.29 23.79 September 23.33 :- 22.74 October 21.62 21.02 Nov'ember 18.18 17.54 December 14.60 14.06 1.>~'" ..> The table above shows that the effluent has the potential to cause thennal shock during June and July and cause a migration blockage during June, Ju]y, August, September, and October. Therefore, effluent temperature limits are needed to mitigate potential spawning impainnents, thennal shock, and migration blockage concerns. City of Ashland Excess Thennal Load Limits February 16,20]] Page 8 of 13 Calculation of Thermal Effluent Limits Based on Thermal Plume Requirements in Ashland Creek SPA WNING IMPAIRMENT: Per the TMDL, the ambient temperatures in Ashland Creek are above 130C during late October. Therefore, per the IMD, the spawning criteria and the human use allowance of 0.1 oC, rather than a thennal plume limitation, will detennine penn it limits. These limits would be temperature limits, in addition to load limits, to prevent spawning impainnent. The temperature limits are as follows: ' Te = (Tc+HUA)(Qe+Qr)-Qr*Tc)/Qe Where, HUA = O.loC Qe = Effluent Flow in cfs Qr = Stream Flow in cfs Tc = applicable numeric criterion = ] 30C THERMAL SHOCK: Pursuant to the Temperatur~. Standard Implementation IMD; .the. following fonnal should be used to prevent the temperature of Ashland Creek from exceeding' 250C after mixing with 5% of the 7QI 0 low flow: . : :. . . Te = D (25-Tr) + Tr Where, D = dilution = (Qe +0.05Qr)/Qe . Tr = 7 day average upstream tempeniture in:oC From the above analysis, thel1)1al shock limitations are only applicable July and August. . MIGRATION BARRIER: PU';suilnt to the Te!l1perature Standard Implementation IMD, the following fonnal should be used to prevent the temperature of Ashland Creek from exceeding 2 JOC after mixing with 25% of~e 7QI 0.10:-" /low: .. Te =: D(2I'.Tr) + Tr From t~e.above analysis,.~ig~ation barrier is only a concern during June through October. SUMMARY OF THERMAL LIMITS FOR ASHLAND CREEK DISCHARGE Montb .:' : Temperature Temperature Limit Temperature Most 'Limit (oC) based (oC) based on Limit (oC) based Limiting "'. , on spa~ning tbermal shock on migration criterion imoairment blockal!e Januarv .13.15 na na Spawning Februarv 13.17 na na Spawning March 13.14 na na Spawning April 13.18 na na Spawning May 13.14 na na Spawning June Na na 30.93 Migration Ju]y Na 25.27 21.82 Migration August Na 25.14 22.37 Migration September Na na 22.79 Migration October 13.16 na 29.54 Spawning City of Ashland Excess Thennal Load Limits February] 6, 20] ] Page 9 of 13 November 13.16 na na Spawning December 13.15 na na Spawning The most limiting criterion would be used to calculate the temperature limit. Note that in addition to the temperature limit above, the City must also meet the excess thermal load (kcal/day). BEAR CREEK OUTFALL EVALUATION The City has also requested an evaluation of the thennal plume effects if the outfall was moved to Bear Creek downstream of the confluence with Ashland Creek. The eyaluation follows: The US Geological Survey maintains a gage in Bear Creek downstream of Ashland Creek. 7Q I 0 /lows for each month at this location were derived using the progran;t pFLOW. These values are presented in the following table: . , . . , Min of Ashland Creek Flow Bear Creek Below Ashland Month above outfall (CFS) 7Q10 flow ICfs) , January 1.36 . , 13.80 . . February 1.66 . ' "16.70 March 0.98 19.40 April 1.67 19.00 May 0.87,-: '.' '. 21.40 June 0.87," ',', ,24,10 July 1.77 . . .23.80 AUQust 1.22 , 28.90 September -, 1.66 . ' 9.22 October / . . . '.. 1.14 4.19 November' 1.13 6.50 December' , , 1.11 11.00 ",. ., . . ~" Since August' 2004; .t:Jie. Jackson' County Water Master has collected temperature data in Bear " , ~ , Creek above the conf1u'ence with. Ashland Creek (near Neil Creek). Using the same methodology as that for ilie'discharge' into Ashland Creek, the following table shows the Bear Creek 7Q1O .stream flow, il)e, averag~' 'STP flow, the average stream temperature, the average STP temperahire,. and the calc~]ated stream temperature after mixing by month: ,. '<< I. Average of 7 day , average , Bear Creek , Bear Creek Average Temps Max of Stream Stream Below of above Effluent Temp Stream Temp Ashland Effluent Ashland Temper after Temp after 7Q10 flow Flow Creek (Deg ature 100% after 25% Month (cIs) (mgd) C) (DegC) mix 5% mix mix January 13.80 2.49 5.15 13.39 6.95 12.14 .9.50 Februarv 16.70 2.35 6.53 13.47 7.77 12.17 9.76 March 19.40 2.27 8.47 15.70 9.58 14.13 11.51 April 19.00 2.19 10.49 17.01 11.48 15.59 13.21 City of Ashland Excess Thennal Load Limits February] 6, 20 I ] Page 10 of 13 Mav 21.40 2.22 13.71 19.99 14.58 18.49 16.16 June 24.10 2.08 17.06 22.06 17.65 20.70 18.80 Julv 23.80 2.04 16.80 25.40 17.81 23.04 19.78 Auaust 28.90 2.01 18.76 25.40 19.40 23.29 20.76 September 9.22 2.02 19.90 23.50 20.81 23.04 21.97 October 4.19 2.00 14.04 21.79 17.33 21.29 19.83 November 6.50 2.01 8.86 18.36 11.94 17 .46 15.10 December 11.00 2.30 4.96 14.74 7.36 13.44 10.48 The table above shows that moving the outfall to Bear Creek below the confluence with Ashland Creek would eliminate thermal shock concerns, reduce that time period when there is potential migration blockage, and provide opportunities to reconfigure . the' 'thennal plume to minimize spawning impainnent. .;.' . .... ~ . . . Calculation or Thennal Effluent Limits Based on Therma/'Plume Requirements in Bear Creek SPA WNING IMPAIRMENT: Salmon and steelhe~d'spawn in t/1e receiving water' downstream of the proposed discharge location in Bear Creek, therei~ potentiallYllctive spawning in:the proposed thennal plume, and the effluent temperature is greater. than ,1,30C.during the spawning season (October 15 through May 15). Additionally, the upstreanHeinperatures are above] 30C in October. Therefore, per the IMD, the spawning criteria and the humahbse, allowance of 0.1 oC, rather than a thennal plume limitation, will detennine' penn it limits in May' and, October. The fonnula for temperature limits is the same as for the Ashhmd:Creek example. .;., Bear Creek is, however, large enough to allow for a small zone of immediate dilution (lID). Bear Creek is approximately 30 feet wide at the proposeddiscliargt;:poirit. For streams of this size, DEQ could propose a mixing zone. up' to 60 feet in length and a ZID that is 10% of the mixing zone. Therefore, DEQ could allow a lID. that reaches approximately 6 feet from the point of discharge. Using the CORMIX model and assuining that the effluent is introduced into Bear Creek through a 4 foot wide channel flush with.the bank, the dilution atthis point is approximately 1.3:], or about 30 percent of the stream flow. -:':, .::,':. . , . THERMAt:SHOCK:. From the'aJ>ove analysis, moving the outfall to Bear Creek would eliminate the po~e?Jial for thennal'shock. '... . . .. . MIGRATION BARRIER: From the above analysis, moving the outfall to Bear Creek would limit the potentia]'for thennal shock to September only. The fonnula for temperature limits is the same as for the Ashland Creek example: SUMMARY OF THERMAL LIMITS FOR ASHLAND CREEK DISCHARGE Month Tenip'erature Temperature Temperature Temperature Limit (oC) based Limit (oC) based Limit (oC) based Limit (oC) on TMDL "UA on spawning on migration criteria and ZlD block3l!e Januarv 13.46 19.53 na 19.5 February 13.56 19.90 na 19.9 March 13.65 18.81 na 18.8 April 13.66 16.27 na 16.7 May 13.72 na na 13.72 June Na na na na City of Ashland Excess Thennal Load Limits February 16, 2011 Page ] ] of] 3 Julv Na na na na August Na na na na Septem ber Na na 22.26 22.26 October 13.24 na na 13.24 November 13.31 15.01 na 15.01 December 13.41 18.77 na 18.77 Note that in addition to the temperature limit above, the City must also meet the excess thennal load (kcal/day), Water Ouality Tradinl! to Meet Thermal Requirements The City is considering water quality trading to meet the thenna] requirements discussed above. Water quality is an innovative approach to achieve water .quality gQals more efficiently than traditional methods. The proposed trade would involve '1on:point source thennal reductions (i.e. riparian improvements or other similar thennal improvements): The framework for evaluating water quality trades is contained in "Water Q!laiity Traqing in NPDES. penn its Internal Management Directive" (Trading IMD). ' ... ., ' Per the Trading IMD, the City may trade their point so'urce'thennal load with non-point source thennalload within the Bear Creek watershed to the poini'ofmaximum impact, which has been detennined to be four miles upstream o(t~e.mouth of Bear cre~K:.However, as discussed above, the City must also meet the thennal plume 'requirements. The Ci'tY may use trading to mitigate thennal plume concerns, however this m;'tigat;'ort .must, be above. the discharge point. This is because cooler upstream temperatures are rieeded.tooffset.near field thermal plume impacts. Earlier evaluations detennined that there is insufficient non-point source reductions available in Ashland Creek abovtHhe 'disc~afge to offset' 'the thermal load. Therefore, without effluent cooling, continued .discharge inio: 'Ashland Creek is unacceptable because of thennal shock, migration blockage: and' sRa:-vning ,i~pairment. ' . . From the eva]uation'above, if the effluenHs:nioved to Bear Creek, no effluent cooling is needed . '" .,.~ . . , ~ , - to eliminate thermal shock concerns. Also, the effluent need only be cooled to 22.30C to eliminate the migration' blockage concerns. Alternatively, the City may implement non-point source' i'e~i1ctions upstrearii a~<1 trade 'fo~' it higher temperature limit. Cooling the'~ffl.uent so that ;ilje temperature of Bear Creek is raised no more than 0,1 would eliminate the potential for spawning impairment. However, water quality trading allows point sources to contin~li :10 d\scharge at a higher temperature. So, even though the thennal load is offset elsewhere in ihe: watershed, the potentia] for localized impacts to salmonid spawning remains. On option for "establishing temperature limits for spawning protection described in the Temperature IMD is to re-configure the discharge to disperse the plume and/or maximize mixing. DEQ has modeled a Fall spawning scenario using the CORM IX model, assuming an effluent temperature of ] 80C and an upstream temperature of II oC. This model shows that the plume is buoyant and initially floats over the spawning area. The model shows that the effluent is cooled to below 130C before it mixes to the bottom of the stream. The following figures are a 3- D view, a plan view, and a profile view of the CORMIX output: City of Ashland Excess Thennal Load Limits February ]6,20]] Page 12 of 13 ~.. 'i // /' / /~.... \ i . ., , ~'" ......... , ,-' , '- " ....... ..". '- ' '...... '" ,,/"" -..",.-..- ~/~ -<-,--- ~~~ -- '.""_'.'_''''-'M', .....,-,.......-,..." ,." ..,.--.,-.".", ='~:::.~ Figure ]. CORMIX 3-D view of side 6~k~ischarge into Bea.r Creek during early spawning season. _ . -~~- ~~;(~ "..u.z"'.................'" .....""....t;..".".,....., ~:..~::::,t';1,_,. ::::"<=''''''''' Figure 2. CORMIX plan view of side bank discharge into Bear Creek during early spawning season. City of Ashland Excess Thennal Load Limits February ]6,201] Page 13 of 13 ....-... .--~l_.___ __ ___._...___________~_ . ----~, -.,....--=--- .~ m.....r - --- ,._~"....,,",""','''';.,'"' ..........,.."""""";.'..r; ~." ;~ '. " ' ." -,'0 "."~ . ::'i:.-::.:::;.,. Figure 3. CORMIX profile view of side ba~k discharge into 'B,ellr. Creek during early spawning season. ., , ;, ~ Therefore, because the effluent is buoyant and because s';me,c!loli~g occurs prior to downward mixing, a higher temperature limit is allowable for a surface discharge. - . ' ~ ' " ' . . " '. , . ~ ~ ~ ~ g'~g :E~~ '" ,,,. 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