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HomeMy WebLinkAbout04/19/2011, SS 5 - UPDATE ON WATER QUALITY REQUIREMENTS FOR THE WATER RECLAMATION FACILITY AND DEDESIGNATION OF SAN LU council MafimD agenda RepoRt "� s CITY OF SAN LUIS OBISPO FROM: Carrie Mattingly, Utilities Director /�'� Prepared By: David Hix, Wastewater Division Manage>i(y, SUBJECT: UPDATE ON WATER QUALITY REQUIREMENTS FOR THE WATER RECLAMATION FACILITY AND DEDESIGNATION OF SAN LUIS OBISPO CREEK RECOMMENDATION Receive and file report. REPORT IN BRIEF Water quality regulations and the State Water Resources Control Board's 1988 action designating San Luis Obispo Creek as a drinking water source have required a variety of studies and resulted in stringent discharge requirements for the City's Water Reclamation Facility (WRF)- Discharge requirements related to the creek being designated as a drinking water source will continue to require significant and costly upgrades to the WRF. While the City has supported requirements that protect the beneficial uses of the creek, studies related to uses of San Luis Obispo Creek water as drinking water, along with an analysis of all regulatory options, have resulted in the City pursuing dedesignation of the creek as a drinking water source. The completed dedesignation study shows that San Luis Obispo Creek has never been, nor can it be, used as a drinking water source. After working with the City on the dedesignation issue for many years, Regional Water Quality Control Board (RWQCB) staff will be asking for direction from the RWQCB on May 5, 2011 as to whether or not RWQCB staff should proceed with agendizing this dedesignation issue for the RWQCB's future consideration. DISCUSSION Studies, discussions, and negotiations with the RWQCB concerning the WRF's National Pollutant Discharge Elimination System (NPDES) permit have been occurring over the last 10 years. The basis of the discussions have centered on water quality regulations that are being driven by San Luis Obispo Creek's beneficial use designation as a drinking water source. The designation will result in more stringent discharge limits in the WRF's future NPDES permit. Meeting these permit limits will require significant and costly upgrades to the facility for a beneficial use the City has proven does not exist. SS5-1 Update on Water Quality Requirements for the Water Reclamation Facility Page 2 Because of the significant impact the required upgrades will have on the community's sewer rates, understanding an overview of the water quality regulations that affect the WRF, becoming familiar with.the related studies, and revisiting the City's on-going efforts to dedesignate San Luis Obispo Creek as a drinking water source will be of benefit to 'the Council and the community. A glossary to water quality regulation acronyms has been provided as Attachment 1. Beneficial Use Designations of San Luis Obispo Creek Basin plans are the guiding water quality documents for each of the State's Regional Water Quality Control Boards. Basin plans list the beneficial uses and associated discharge limits to protect those beneficial uses for every water body in a region. Beneficial uses are the driver for establishing water quality objectives for a water body, which in turn are used to determine discharge limits such as those put in NPDES permits. The City's water bodies, which include San Luis Obispo Creek, fall under the Central Coast RWQCB's basin plan. The Central Coast Region is bounded by the Santa Cruz Mountains in the north, south almost to Ventura, and east and west from the coastal range to the Pacific Ocean respectively.. San Luis Obispo Creek has beneficial uses listed in the basin plan such as freshwater habitat, recreation, groundwater recharge, shellfish harvesting, and municipal and domestic supply (MUN). MUN was placed in every inland water discharger's NPDES permit after 1988 when the State Water Resources Control Board (SWRCB) adopted Resolution 88-63 resolving that all surface waters in the State are considered a municipal or domestic supply. The MUN beneficial use generally has the most stringent discharge limits. San Luis Obispo Creek is naturally an intermittent coastal stream that, during drier portions of the year, may have no natural flow from the watershed. During most of the year, the WRF's discharge into the creek makes up a majority of the flow, therefore the creek is considered an effluent-dominated water body. In order to maintain creek flows, preserve habitat, and protect the habitat beneficial uses, California State Fish and Game and National Marine Fisheries Service mandated the City discharge a minimum of 1.6 million gallons per day(MGD) as a condition of the City's recycled water program. San Luis Obispo Creek now has flow all year downstream of the WRF. The Water Reclamation Facility The City of San Luis Obispo began treating wastewater and discharging it to San Luis Obispo Creek in the 1940's. Periodic upgrades of the facility have been required for capacity and treatment improvements. The last upgrade was completed in 1994 after the City and RWQCB entered into a regulatory compliance agreement, referred to as a consent decree, to ensure the City complied with discharge requirements developed for San Luis Obispo Creek. These discharge requirements did not include the MUN beneficial use. SS5-2 Update on.Water Quality Requirements for the Water Reclamation Facility Page 3 The $25 million upgrade resulted in the City's current tertiary treatment plant, which complies with some of the most stringent discharge requirements in the State. The tertiary process installed in 1994 removes ammonia, then filters and cools the effluent before discharging it to the creek. By preserving and improving the creek's cold freshwater habitat there has been a significant return and increase in freshwater flora and fauna, including large numbers of steelhead trout. Because the MUN beneficial use was placed into the WRF's NPDES permit after design and financing of the WRF upgrade had been completed, the 1994 WRF upgrade did not include processes that met the MUN criteria. The WRF currently treats approximately 4.5 MGD of wastewater with a capacity of 5.1 MGD. Nitrates The WRF processes convert ammonia found in wastewater to nitrate to ensure the discharge is not toxic to the Creek's freshwater habitat. In 2000 the RWQCB informed the City it would require the WRF to meet the basin plan requirements for the MUN beneficial use and reduce the amount of nitrates it discharges to the creek. While the nitrates being discharged to the creek are safe for the freshwater habitat, they exceed the MUN basin plan limit, a limit that is more stringent than the City's potable drinking water standard of 10 milligrams per liter(mg/L) for nitrate. Beginning in 2001, a nutrient study of San Luis Obispo Creek was initiated by the RWQCB. The study was completed in 2005 and adopted in 2006. This study, referred to as a Nutrient Total Maximum Daily Load (TMDL), determined the acceptable amount of nutrients, specifically nitrates, from the watershed that may be allowed into San Luis Obispo Creek, while protecting the beneficial use, in this case MUN. TMDL's are initiated after the water body has been listed by the SWRCB as impaired for one or more beneficial uses. In this case the impaired use was MUN for nitrates. City staff contended the study lacked sufficient analysis to prove the MUN beneficial use exists or could ever be attained, even with treatment. City staff also testified and submitted comments to both the RWQCB and SWRCB requesting adequate time to complete a study to look at the dedesignation of San Luis Obispo Creek for MUN. Despite the City's request for time to adequately study dedesignation, the RWQCB, and eventually the SWRCB, adopted the TMDL in June 2006. The TMDL required the City to meet a 10 mg/L nitrate limit to achieve the MUN use by the end of 2012. The WRF's current nitrate discharge is 25 mg/L. Achieving a nitrate limit of 10 mg/L would require significant, costly process upgrades for a beneficial use that has been proven to not exist. During the TMDL adoption process, the City requested, and the RWQCB agreed, that a different effluent limit would be considered if the MUN use was revised or removed. SS5-3 Update on Water Quality Requirements for the Water Reclamation Facility Page 4 State Water Quality Regulations The SWRCB adopted the California Toxics Rule (CTR) and the corresponding State Implementation Plan (SII') to regulate discharges of toxic pollutants into inland surface waters. The CTR, which utilizes stringent water quality objectives, identifies pollutants, develops a discharge limit for each pollutant, and assigns a compliance schedule to meet the discharge limit per the SIP. The pollutants and their concentrations are based upon the beneficial use designations of the receiving water. Several more stringent discharge requirements have been identified for the WRF, in addition to the basin plan discharge limits. San Luis Obispo Creek is a relatively small water body which offers very little natural stream flow dilution to the effluent discharged by the WRF. This results in the creek being categorized as "effluent-dominated" and requires regulators to assign discharge limits with no dilution credit. All discharge requirements must be met at the "end of pipe", which is the location where the WRF discharges into the creek. This results in the most stringent limits possible. Overview of Special Studies In 2002, the WRF's updated NPDES permit required a variety of special studies because of the adoption of the CTR. Some of the study findings required the WRF's permit to be reopened and revised with new discharge requirements, additional studies, and compliance schedules. Following are summaries of key studies. Reasonable Potential Study (RPA). This analysis is required for all wastewater facilities to determine if the water quality objectives for receiving waters are being met. Extensive sampling was required to determine what pollutants were being discharged from the WRF into San Luis Obispo Creek. The RPA determined that two pollutants were consistently not meeting the discharge limits. These pollutants are known as trihalomethanes (THMs); specifically chlorodibromomethane and dichlorobromomethane. These pollutants are currently in the WRF's permit with achievable interim limits. THMs are the by-product of chlorine (used at the WRF as a disinfectant) and organic matter found in wastewater. The development of the water quality objective for THMs is based on the MUN beneficial use designation and the federal human health criteria. The human health criteria assumes an exposure path based on drinking 2 liters of untreated creek water and eating 6.5 grams of fish every day for 70 years, with the result being a greater than one in a million chance of contracting cancer. To highlight the regulatory conundrum, the WRF's interim discharge concentration for THMs meets the California Department of Public Health (CDPH) drinking water requirement but does not meet the water quality objective. Trihalomethane Fate Study. The City requested a trihalomethane (THM) fate study to determine if THMs volatilize or attenuate somewhere downstream of the WRF's outfall. The study showed that THMs met the CTR requirement approximately 29,000 feet downstream of the WRF's outfall, approximately where the creek crosses under Highway 101. This distance or"point of compliance" was too far downstream for the RWQCB staff to accept as being in compliance with the proposed SS5-4 Update on Water Quality Requirements for the Water Reclamation Facility Page 5 THM limits. While the study did not achieve the outcome the City had hoped for, it does provide important information and an opportunity for the City to continue further studies in an effort to establish a more acceptable point of compliance and/or develop alternative water quality objectives. Nutrient and THM Groundwater.Study. This study looked at concentrations of THMs and nutrients in the groundwater above and down gradient of the WRF's outfall. Sampling and record review determined that the WRF effluent was not degrading or responsible for degradation of the groundwater below its outfall. Disinfection Alternatives. Chlorodibromomethane and dichlorobromomethane limits were placed in the WRF's revised NPDES permit in 2005. The City was given a five year compliance schedule to meet the more stringent permanent limits by March 1, 2010. The proposed permanent limits are approximately 100 to 200 times lower than the current drinking water standard (10 milligrams per liter vs. 80 micrograms per liter). The permit also required the City to study and evaluate reduction strategies for THMs. From 2005 to 2009 studies were performed to look at in-plant THM generation caused by the chlorine in separate processes and for final disinfection. Several disinfection alteratives were analyzed resulting in a compound called chlorine dioxide being pilot tested. The test results showed chlorine dioxide to be a viable alterative to chlorine. Use Attainability Analysis,Dedesignation, and the WRF's Current Permit In May of 2005 the City Council authorized the City's regulatory consultant, Larry Walker Associates (LWA), to perform a feasibility analysis of all available regulatory options. The analysis determined that a Use Attainability Analysis (UAA) to study the reasonable beneficial uses of San Luis Obispo Creek was the most feasible and favorable regulatory option the City should pursue. After addressing questions and concerns posed by RWQCB staff, a completed working UAA document was finalized in 2007. LWA followed specific guidelines developed by the EPA for removing beneficial uses and by utilizing the exceptions provided in the SWRCB's Resolution 88-63 that established all surface waters in the State as municipal or domestic supply to create the UAA.. The UAA found no historic or present use of the creek for drinking water and that no level of treatment would allow the creek water to be used for MUN. While downstream of the WRF there are several State- permitted water systems that utilize groundwater, the study showed, utilizing records from the CDPH and hydraulic studies, that no connection or"communication"of groundwater and surface water from San Luis Obispo Creek exists. The City and RWQCB have maintained contact with downstream users and provided updates and copies of correspondence related to the UAA process. To verify if the initial findings of the draft document were valid, the City contacted CDPH to review the UAA. Its response was as follows: "Currently, the surface water in SLO creek is not used for domestic purposes. Based on the evaluation contained in the attachment to your letter, the high percentage of wastewater effluent in the surface water source would not be an appropriate source of domestic drinking water supply even if the water met the chemical drinking water standards. " SS5-5 i Update on Water Quality Requirements for the Water Reclamation Facility Page 6 No conditions or additional information have changed since this finding. San Luis Obispo County Environmental Health provided a similar letter to the City. The State and County's correspondence is attached to this report(Attachments 3 and 4). The UAA definitively confirms that the MUN beneficial use does not and never has existed and could not be achieved even if the WRF were upgraded to remove nitrates. Upgrading the WRF to comply with the MUN discharge requirements would not achieve the MUN beneficial use, but merely comply with the MUN policy. The City has provided this information to the RWQCB staff. Board staff has remained engaged with the City in its continuing efforts to explore options to dedesignation. In May of 2007 the WRF's NPDES permit was slated to expire. Reissuance of the revised permit would have required a five year compliance schedule to achieve the MUN discharge limit. During the application process in spring of 2007, the City and RWQCB agreed to administratively extend the current permit until the dedesignation of San Luis Obispo Creek could be resolved.. The administrative extension of the WRF's permit has allowed for additional studies and discussion to occur and for the deferral of the significant costs of the WU upgrade. This deferral has allowed the City to better refine possible alternatives for treatment and regulatory options such as Site Specific Objectives for THMs. Time Schedule Order and Site Specific Objectives The City has completed all the required THM studies required in the WRF's NPDES permit. The dedesignation process is not complete and, in March 2010, the RWQCB agreed to extend the THM compliance schedule an additional five years by approving a Time Schedule Order(TSO). The TSO, adopted by the RWQCB on March 31,2010, grants the City additional time to present options to meet the THM discharge limits. This action avoids any possible permit violations and penalties related to THMs for five years. Since TSO adoption, the City has explored the use of Site Specific Objectives (SSOs) to comply with THMs. An SSO is a water quality objective adjusted to reflect local conditions. An SSO is developed by changing various factors (such as risk and water chemistry effects) used in the water quality objective to derive the appropriate limit to protect the water body. While this is a viable option for compliance with the THM limits, an SSO is not a viable option for compliance with the nutrient (nitrate) limit. Additionally it does not protect the City from future regulatory requirements related to the MUN beneficial use. The data demonstrates the most viable regulatory strategy to meeting the THM limits is dedesignating San Luis Obispo Creek for MUN. The TSO has a compliance date of March 31, 2015. SS5-6 Update on Water Quality Requirements for the Water Reclamation Facility Page 7 WRF Master Plan WRF master planning efforts began in 2003. This work has been delayed due to various factors, one of which is the regulatory decision regarding the MUN designation. The Master Plan, which has just been completed, analyzes WRF treatment and capacity, along with existing infrastructure needs within the plant. The treatment requirements to meet the MUN water quality objective will require a denitrification process to reduce the nitrate concentration of the WRF's effluent. There are a variety of processes that can be used to accomplish this, all of which require significant capital expenditures and ongoing operating cost increases. The MUN beneficial use designation is the largest single driver in the cost of upgrading the WRF. Other major cost drivers of the WRF upgrade are additional capacity required to provide treatment for the eventual build out of the City per the General Plan and many infrastructure components that are over 50 years old that require upgrade or full replacement. The WRF Master Plan will be presented to Council this spring. At that time Council will receive an in-depth presentation regarding the recommendations in the MasterPlan including alternatives associated with removal of the MUN designation of San Luis Obispo Creek. Summary Since 2009 the City and RWQCB have been meeting regularly to discuss the dedesignation of San Luis Obispo Creek for MUN and issues related to the TSO. In response to a meeting between RWQCB and City staff, the RWQCB sent the City a letter on March 16, 2009, which stated "Water Board staff concludes that based on the information provided, the Clean Water Act does not preclude dedesignation of the Creek itself for MUNI" The City has explored all regulatory options, completed numerous studies and analyses, and explored alternatives to dedesignation with RWQCB staff. One result of investigating these alternatives has been the timely adoption of the TSO. These efforts have been time-consuming and challenging and RWQCB staff deserves recognition for remaining engaged in discussions and for its respect of the regulatory process. The RWQCB Executive Officer has agreed to agendize an item for RWQCB consideration at its May 5, 2011 meeting, as to whether or not its staff should prepare a future item on dedesignation of San Luis Obispo Creek for MUN. The RWQCB is being introduced to the dedesignation item for the first time at this meeting. This is a key step in the City's efforts to remove the MUN beneficial use designation. Staff has provided information to RWQCB staff for the May 5, 2011 meeting detailing why it is appropriate to dedesignate San Luis Obispo Creek for MUN and requesting it direct its staff to prepare a future agenda item for dedesignation. The City will have an opportunity to present its position on this item at the Board meeting. SS5-7 i Update on Water Quality Requirements for the Water Reclamation Facility Page 8 The outcome of the May 5, 2011 meeting will inform the next steps for the City. If the RWQCB directs its staff to move forward and MUN dedesignation is approved at the regional level, ideally the dedesignation recommendation will go to the SWRCB it Sacramento and then on to the Environmental Protection Agency for final approval. The entire dedesignation process will take at least two years. Dedesignation is a resource intensive activity and the City will need to provide resources as required for basin plan amendments and other studies and analyses. If the RWQCB does not support dedesignation, either at its May 5 meeting or at a future meeting, then staff will return to Council with a recommendation for regulatory and legal actions and alternatives. The upcoming 12 months is critical to the City for planning the WRF's upgrade and developing an effective and appropriate regulatory and legal strategy. Any of these next steps will require the City dedicate additional resources to these efforts. Staff will return to Council at a later date for expenditure authorization for consultant services on this matter. Stam' will continue to work closely with the RWQCB on all regulatory issues related to the WRF's permit, new and proposed regulations, and beneficial uses of San Luis Obispo Creek. The process of utilizing all the regulatory options available has enabled the City to have the time to study and determine the most appropriate avenue to address these issues for the City and San Luis Obispo Creek. This effort will allow the future upgrades at the WRF to meet the appropriate discharge requirements cost effectively and efficiently. Staff will return periodically to update Council on new regulations that may affect the WRF and with requests for additional studies if needed or required. FISCAL IMPACT Additional funds will be required to complete the dedesignation process. Staff will return to Council to authorize further regulatory and legal consultant services. The following tables summarize costs associated with regulatory activities and the future WRF upgrade. Table 3 shows the consultant's estimated costs for design and construction management, and construction of the WRF upgrades. Implementation and completion dates may change dependent upon the WRF's revised permit and the City's required build-out capacity. Table 2. Completed Regulatory Activities and Studies Activity Implementation Date Completion Costs RPA, THM, Groundwater Studies March 2002 Ma -Oct 2005 $186,200 Regulatory tions May 2005 January 2006 $92,000 Use Attainability Analysis/Designation April 2006 Ongoing $119,400 Chlorine Dioxide Disinfection Study December 2005 May 2009 $146,000 WRF Master Plan Jan 2003 May 2011 $320,000 Total $863,600 SS5-8 i Update on Water Quality Requirements for the Water Reclamation Facility Page 9 Table 3. Future Regulatory Study,Design, and Construction Activities Activity Implementation Date Completion Costs Design and Construction Management Winter 2013 Summer $8,000,000 of Upgraded WRF 2014 Construction of Upgraded WRF Spring 2015 Fall 2017 *$56,300,000 to $30,840,000 Total *$64,805,600 to $44,840,000 *This range is the difference between upgrades required for adding processes to meet MUN and meeting current permit requirements.It equals$20 million.These estimates are based on the consultant's WRF master planning data. Staff is actively pursuing alternatives to reduce costs associated with the plant upgrade,but sewer rates are being incrementally increased to conservatively support the estimated debt service for the plant construction. ATTACHMENTS 1. Glossary of Acronyms 2. Map of San Luis Obispo Creek Watershed 3. California Department of Public Health Letter 4. County of San Luis Obispo Environmental Health Letter Council Reading File: Draft Use Attainability Analysis Working Document SS5-9 I ATTACHMENT 1 Glossary of Water Quality Acronyms CDPH. California Department of Public Health. California State agency that establishes drinking water standards and permits and inspects drinking water treatment and distribution systems. CTR. California Toxic Rule. Water quality policy document for discharges of pollutants to inland surface water bodies, enclosed bays and estuaries. Adopted in March 2000. MUN. Municipal and Domestic Uses. Uses of water for community,military or individual supply systems,but not limited to drinking water. NPDES. National Pollutant Discharge Elimination System.National permitting program that controls water pollution by regulating point sources that discharge pollutants into waters of the United States. In California this program is administered by the State. RPA Reasonable Potential Analysis. An analysis to determine which pollutants in the discharge have a reasonable potential to violate water quality standards. RWQCB Regional Water Quality Control Board. The nine.Regional Boards are comprised of nine part-time appointed Board members. Regional boundaries are based on watersheds and water quality requirements are based on the unique differences in climate, topography, geology and hydrology for each watershed. Regional Board's make responsibilities include setting standards, issuing waste discharge requirements, determining compliance with those requirements, and taking appropriate enforcement actions. SIP. State Implementation Plan. Implementation guidance plan for CTR SSO. Site Specific Objective. A specific water quality objective adjusted to reflect local conditions. SWRCB. State Water Resources Control Board. Five-member appointed Board that is tasked with protecting water quality by setting statewide policy, coordinating and supporting the Regional Water Board efforts, and reviewing petitions that contest Regional Board actions. The State Board is also solely responsible for allocating surface water rights. THMs Trihalomethanes. Compound created by the interaction of chlorine and organic matter. TMDL Total Maximum Daily Load. A calculation of the maximum amount of a pollutant that a water body can receive and still meet water quality standards, and an allocation of that load among the various sources of that pollutant. SS5-10 Glossary of Water Quality Acronyms Page 2 of 2 ATTACHMENT 1 TSO Time Schedule Order. A compliance schedule issued by the RWQCB to develop, submit, and implement methods of compliance. WRF. Water Reclamation Facility. The City's wastewater treatment and water recycling facility located at 35 Prado Road. UAA. Use Attainability Analysis. A structured scientific assessment of factors affecting the attainment of the use which may include physical, chemical,biological and economic factors as described in 40 Code of Federal Regulation(CFR) 1313.10(g) SS5-11 SLO Creek Reach Downstream of WRF ® San Luis Obispo Creek Watershed Q Stream Gauge =moi`' \ v { o r o . i{'-1..a\•`,y ��� slt. \r•` I ._ ao � • � � 11 � -�- I 1 •� West Marsh Street \I ' � �� .'�- ..-Vlr� by ♦ ` ,- L t'�. .•ti��.-� J ti VAS i , �.✓ `^ty� 11� � City of San Luis Obispo Water Reclamation Facility Outfall ' o l 41, 1 5 County Stream Gauge Point ofTHM e Compliance San„t.uis Oblapotuary �. ... 0 0.5 1 2 Miles a„ v,: ” Location _ ATTACHMENT 3 -J State of Califomia—Health and Human Services Agency Department of Health Services California De Mentof Health Semces •- SANDRA SHEWRY ARNOLD SCHWARZENEGGER Director Governor June l, 2006 John Moss, Utilities Director City of San Luis Obispo 25 Prado Road San Luis Obispo, CA 93401 Dear Mr. Moss The California Department of Health Services has reviewed your letter dated May 17, 2006 concerning the use of surface water in the San Luis Obispo Creek as a domestic supply of water. Currently, the surface water in the SLO Creek is not used for domestic purposes. Based on the evaluation contained in the attachment to your letter, the high percentage of wastewater effluent in the surface water source would not be an appropriate source of domestic drinking water supply even if the water met the chemical drinking water standards. The CDHS does regulate ground water sources near the SLO creek downstream of the wastewater treatment plant. These wells currently meet drinking water standards. If you have any questions, please call this office at(805)566-1326. Sincerely, Kurt Souza, P.E., Chief Southern California Section CDHS-DWPOB Cc: SLO County EHD Chris Rose, RWQCB H:San Luis Obispoll.05 26 2006.doc Southern California Drinking Water Field Operations Branch 1186 Eugenia Place,suite 200, Carpinteria,CA 93013-2000 (805)566-1326;(805)745-81 96 fax Internet Address: hftp://www.dhs.ca.gov/ps/ddwom/default.Mm SSS-13 ATTACHMENT 4 SAN LUIS OBISPO COUNTY HEALTH AGENCY Public Health Department 191 Johnson Avenue•P.O. Box 1489 City of Sen Luis Obispo j Utllitles Department San Luis Obispo, California 93406 i 805-781-5500•FAX 805-781-5543 SEP _ 2010 Je.{fHamm Health Agency Director August 30, 2010 Penny Borenstein, MD., MP.H. p=ehed Health Officer David Hix City of San Luis Obispo Wastewater Division Manager 879 Morro Street San Luis Obispo, CA 93401 RE: Use of San Luis Obispo Creek as a Source of Drinking Water Dear Mr. Hix: In your letter of June 29, 2010 you asked for the opinion of the County Health Department as to whether the use of the water in San Luis Obispo Creek downstream of the Water Reclamation Facility (WRF) could be permitted as a source of municipal drinking water. You also asked if wells withdrawing groundwater.under the direct influence (GWUDI) of San Luis Obispo Creek downstream of the WRF could be used as a source of drinking water. The answer to both of these questions is"no". Based on the data you includedin your letter, San Luis Obispo Creek is an effluent dominated stream for at least eight months of the year. As District Engineer Kurt Souza of the state Drinking Water Program stated in his letter of June 1, 2006"the high percentage of wastewater effluent in the surface water source [San Luis Obispo Creek]would riot be an appropriate source of domestic drinking water supply even if the water met the chemical.drinking water standards.' The county agrees with this statement and.would not approve the using water withdrawn from San Luis Obispo Creek as a source of drinking water for any system that would be under our jurisdiction. This same restriction would apply to any well considered to be withdrawing GWUDI of San Luis Obispo Creek. The San Luis Obispo County Public Health Department issues permits for all wells proposed to be drilled in the county; a well location so close to SLO Creek that it would contact GWUDI would not be approved. The basic problem with water from this creek is that its quality (and therefore its usefulness as a source of drinking water) is highly dependent on the WRF operating flawlessly on a continuous basis. Such a treatment standard would be virtually impossible to maintain. Even if the creek water met all applicable drinking water standards and California Toxic Rule criteria (as determined by a SS5-14 ATTACHMENT 4 series of rigorous laboratory tests), there can be no certainty that a disruption of the treatment plant process would not release harmful pollutants into the stream. Thank you for the opportunity to comment on this proposed use of the water in San Luis Obispo Creek. If you have any questions or need any additional information please contact me at my office (805) 788-2049. Sincerely, r P/S.�B'tJ Bradley Prior, EHS Environmental Health Specialist III Cc:Kurt Souza, District Engineer California Dept. of Public Health Drinking Water Program 1180 Eugenia Place Carpenteria, CA 93013 PAEH\EH_Common\Water\Water Systems\Correspondenoe\SLO Creek Drinking Water.doc SS5-15