NPDES) PERMIT Permit Evaluation Review Report

NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES) PERMIT Permit Evaluation Review Report

Oregon Department of Environmental Quality 2020 SW Fourth Avenue, Suite 400 Portland, Oregon 97201 503-229-5263 FAX 503-229-6945

Final

Permittee: City of Portland Facility Location: Bureau of Water Works 16400 NE Airport Way, Portland Oregon. 2010 N Interstate Ave. Portland OR 97227

Sources Covered: Numerous Receiving Stream: Columbia River, Johnson Creek, Columbia Slough, Bull Run River, Sandy River, and various other streams and creeks

Source Category: Minor industrial Proposed Action: Permit modification

File Information: Source Contact: WQ-Multnomah County Curt Ireland, PE File No. 70730 503/823-7598 EPA Reference No.: OR-003113-5 Application Date: 26 July 2005 Application No. 980672 Permit No. 101617 Preparer: Date Prepared: Elliot Zais, PhD, PE 15 October 2007 Water Quality Source Control Section Preparer, Signature: Northwest Region 503/229-5292 / - Portland Water Bureau Evaluation Report Page 2 of 23

Fact sheets are required by EPA regulations to include the following items when applicable.

A brief description of the type of facility or activity which is the subject of the draft permit;

The type and quantity of wastes, fluids, or pollutants which are proposed to be or are being treated, stored, disposed of, injected, emitted, or discharged.

A brief summary ofthe basis for the draft permit conditions including references to applicable statutory or regulatory provisions and appropriate supporting references to the administrative record required by §124.9 (for EPA-issued permits);

Reasons why any requested variances or alternatives to required standards do or do not appear justified;

A description of the procedures for reaching a final decision on the draft permit including:

(i)The beginning and ending dates of the comment period under §124.10 and the address where comments will be received;

(ii) Procedures for requesting a hearing and the nature of that hearing; and

(iii) Any other procedures by which the public may participate in the final decision.

Name and telephone number of a person to contact for additional information.

Justification for waiver of any application requirements under §122.21 (j) or (q) of this chapter.

Any calculations or other necessary explanation of the derivation of specific effluent limitations and conditions or standards for sewage sludge use or disposal, including a citation to the applicable effluent limitation guideline, performance standard, or standard for sewage sludge use or disposal as required by §122.44 and reasons why they are applicable or an explanation of how the alternate effluent limitations were developed.

When the draft permit contains any of the following conditions, an explanation of the reasons that such conditions are applicable:

(i) Limitations to control toxic pollutants under §122.44(e) of this chapter;

(ii) Limitations on internal waste streams under §122.45(1) of this chapter;

(iii) Limitations on indicator pollutants under §125.3(g) of this chapter;

(iv) Limitations set on a case-by-case basis under §125.3 (c)(2) or (c)(3) of this chapter, or pursuant to Section 405(d)(4) of the CWA;

(v) Limitations to meet the criteria for permit issuance under §122.4(i) of this chapter, or

(vi) Waivers from monitoring requirements granted under §122.44(a) of this chapter.

INTRODUCTION

The City of Portland owns and operates a ground water pump station located at 16400 NE Airport Way, Portland Oregon.

The City's NPDES permit was renewed in 2004. It expires on 31 December 2007.

FACILITY DESCRIPTION AND UPDATE

The facility was completed in 1984. The primary purpose ofthe station is to receive ground water from 27 existing wells in the area and pump it to the Powell Butte Reservoir for Portland Water Bureau Evaluation Report Page 3 of 23

distribution to the City's water supply system. Pumping is accomplished with six 14 000 gpm turbine pumps. Total pumping capacity is 120 MGD.

The City also occasionally drains water supply conduits for scheduled maintenance. These discharges are included under this permit with appropriate monitoring and reporting requirements. The City normally drains conduits into dry wash areas where discharge will not affect stream water quality. In areas where this is not practical, the City reduces the discharge chlorine concentration by either flushing the conduit with non-chlorinated water or by dechlorinating the water with ascorbic acid (vitamin C).

The following discussion is taken from the City's 2004 renewal application. It is still relevant.

The Water Bureau originally applied for this permit in 1982 solely for the discharge of potable water to the Columbia River that would result from proposed electrical power generation activities. Other than an initial test run, no hydroelectric operations have been conducted since. The conduit blowoffs were added during the permit renewal in 1987. More groundwater collection system outfalls were added during the last permit renewal and the 1998-1999 permit modification process. This permit has slowly evolved over time to cover most of the outfalls associated with the Bureau's water supply system. Over this same period, we have developed a better understanding of NPDES permitting requirements.

Given this, it makes sense at this time to include the remaining outfalls in this permit renewal application. This will result in the final permit applying to all established points of discharge for the water supply system. These outfalls are associated with Powell Butte Reservoir and the blowoffs on the inlet and outlet transmission lines connecting the Ground Water Pump Station, the three Bull Run conduits and the Powell Butte Reservoir. By including these sites in this permit renewal, it is our intent to rectify any prior omissions. Attached are a site map and a written description of the discharges occurring at Powell Butte Reservoir (Attachment 005). Drawings ofthe conduit inter-ties with blowoff locations are included in Attachment (005 A-L). A GIS map ofthe blowoffs on the Groundwater Transmission Main and Powell Butte Inlet and outlet Lines are also included in this attachment.

As we have discussed previously, the Bureau is planning to build a pump to waste line to the Columbia River for the Blue Lake Aquifer wells. At this writing, construction is approximately two years out. It will almost certainly occur within this upcoming permit cycle so we are going to include this new outfall with this permit renewal application. This future outfall will be designated as 001-F. Attached is a map showing the approximate location of the proposed outfall and a preliminary drawing showing its construction (Attachment 001-F)

During this last permit cycle there have been a number of changes with regard to the groundwater system. Three new Aquifer Storage and Recovery (ASR) wells Portland Water Bureau Evaluation Report Page 4 of 23

have been drilled and one existing well has been modified for ASR. In compliance with DHS rules, all four of these wells have dedicated pump to waste lines. Well 35 was drilled at the same location as Wells 26 and 32 and discharges from the pump to waste line also go to Outfall 001-C. Well 36 is located on the Ground Water Pump Station site and its pump-to-waste line discharges to Outfall 001-A as described in our letter of May 15, 2002.

Well 37 was drilled at the old Well 23 site on Holman Street. The pump to waste line discharges into a Multnomah County Drainage District (MCDD) ditch adjacent to the site. Water travels westward going under I-205 and enters the Port of Portland storm sewer system. Eventually it enters the Slough just west of Glass Plant Road via a MCDD outfall. We propose to designate the outfall for the discharges from this well as Outfall 001-G. Attached is a map ofthe site, outfall construction details, and a map showing the path taken by water discharged from the pump to waste line (Attachment 001-G).

Well 8 was modified to become an ASR well. A new pump to waste line was constructed at the site. This line discharges into a ditch that is part of the City of Gresham storm sewer system and eventually enters the Columbia Slough just east of 185th Avenue. We propose to designate the outfall for the discharges from this well as Outfall 001-H. Attached is a map ofthe site and a map showing the path taken by water discharged from the pump to waste line (Attachment 001-H). Also included with this attachment are details ofthe outfall structure.

While preparing this renewal application package, it became apparent that there was a need for better identifying each outfall specifically. Previously, the groundwater collection system outfalls were identified as Outfalls 001-A through 001-E and the conduit blowoffs as 002 (various) with each one identified by its conduit station number listed in a table. There were slightly over one hundred conduit blowoffs listed. In order to simplify things and assign each outfall a unique identifier, we propose to modify the outfall numbering system as follows:

Outfall 001 series - Ground Water Pump Station and groundwater collection system Outfall 002 series - Conduit 2 blowoffs Outfall 003 series - Conduit 3 blowoffs Outfall 004 series - Conduit 4 blowoffs Outfall 005 series - Powell Butte Reservoir and inlet/outlet line blowoffs

In addition to the attachments mentioned above, we have provided the following information as attachments to Form 2C:

Attachment 1 is a table listing all the discharge points (outfalls) for the water supply system. Table I - Outfall Locations provides information pertaining to location, flow rates and volumes, and receiving system for each outfall. This table is intended to fulfill the requirements of Part I of Form 2C. Portland Water Bureau Evaluation Report Page 5 of 23

Attachment 2 shows schematic drawings of the water supply system and the entire supply and distribution system. The water supply system schematic shows the aforementioned outfall series locations and points of chemical addition. The schematic ofthe entire system is provided to satisfy the requirement in Part IIA, which requests that a line drawing showing water flow through the facility be submitted.

Attachment 3 is a table of all the groundwater production wells, their pumping rates, and construction details (Table II). Also included in this attachment is a map showing the locations of these wells and collection system outfalls. This attachment is meant to satisfy Part IIA as well.

Attachment 4 consists of an Operations and Treatment Table (Table III) that summarizes the types of operations and activities, the frequency, flows, and treatment provided for each outfall or groups of outfalls. This table also shows the types of water (versions of Table V) that will be discharged from each of the various outfalls.

Attachment 5 is information concerning the data used for completing the various versions of Table V. The constituents we typically monitor are for compliance with drinking water regulations. These constituents are not necessarily the same ones that are required for compliance with environmental rules and regulations. We have tried to report the data in the desired format using existing water quality data without generating large volumes of statistical reports only for this purpose.

We have completed six versions of Table V (Form 2C). There are two primary sources of supply, surface water from the Bull Run watershed and groundwater from the Columbia South Shore Wellfield. In addition, there are blends ofthe two sources.

Bull Run water comes in two types. The first is free chlorinated which is discharged from the blowoffs between Headworks and Lusted Hill. At Lusted Hill the pH is adjusted and ammonia is added to form chloramines. The values for all constituents in Version 1-A (free chlorinated) are the same as Version 1-B (chioraminated) with the exception of chlorine residual, ammonia, and pH. pH for free chlorinated water tends to be about one standard unit less than for the chioraminated version due to caustic soda addition at Lusted Hill. This is the primary reason there are two versions for Bull Run surface water.

Groundwater is also discharged to two forms, native and chlorinated. The values for all parameters in Version 2-B (chlorinated) are generally the same as Version 2-A (native) with the exception of total chlorine. Values for Version 2-A were compiled from data collected from all wells over past three years. pH values for both types are highly dependent on which wells are being pumped at any given time. No distinction is made in this case between free chlorinated and chioraminated water, as the concentrations in terms of total chlorine are very similar. Portland Water Bureau Evaluation Report Page 6 of 23

Bull Run surface water and groundwater are blended in two ways. Groundwater is used occasionally to augment Bull Run water in the summer and early fall to stretch supplies until refill occurs in the Bull Run reservoirs. This native groundwater / Bull Run blend is Version 3-B. The ratio of groundwater to Bull Run water varies according to demand and wellfield constraints. Because of this, water quality data can vary considerably. For this version of Table V, groundwater contribution was assumed to be 33 percent. Values for this version of table where there was no actual water quality data were calculated from those values in Version 2-B (33%) and Version 1-B (67%).

The other blend is water extracted from ASR wells. Bull Run water is injected during the winter months into a number of ASR wells. This water is periodically pumped to waste for sampling and testing purposes. However, its primary purpose is to supplement Bull Run supplies during Bull Run reservoir drawdown in the summer months. This version of Table V is Version 3-A.

The Hudson's Road Inter-tie Facility outfall was added in 2005 as Outfall 005 M. This renewal will add the proposed Sandy River Conduit Crossing as Outfall 005 N.

UNIQUE OPERATING CONDITIONS AND PROBLEMS

No unique operating conditions or problems are known.

STORM WATER

No stormwater permit is required for this facility.

GROUNDWATER

Ground water is not an issue for this permit.

OUTFALL

The outfalls are on the Columbia River, the Columbia Slough, Blue Lake, Johnson Creek, Bull Run River, Sandy River, and various other creeks and streams. The slough and the lake drain to the Willamette River. The outfalls were renumbered at the last renewal in order to simplify keeping track of over 100 biowoff locations. A new outfall is proposed for the Sandy River.

THREATENED AND ENDANGERED SPECIES REVIEW Portland Water Bureau Evaluation Report Page 7 of 23

The Water Bureau provided the following review of their discharges with respect to threatened and endangered species.

In this discussion, the focus will be on the potential effects of Water Bureau discharges during the summer and early fall when temperature increases in surface waters are of concern.

The Columbia Slough receives Water Bureau discharges from the groundwater system. This water body is classified as Salmon and Trout Rearing and Migration habitat. The water quality standard for this use during the months of July and August in this classification is 18 °C. (We understand that DEQ currently has in review a temperature TMDL for the Slough, but we will, for these purposes focus on the generally applicable numeric standard for the rearing and migration classification.) Over the period 2000 - 2003, the average water temperature for all wells was 13.8 °C. With few exceptions, groundwater temperatures stay somewhat constant and generally do not vary more than 2 °C at any particular well. During this period, average temperatures at two stations in the Columbia Slough averaged 18.9 °C for the months of July and August. It is expected that Water Bureau discharges during these months would tend to decrease temperatures in the Columbia Slough somewhat because of the lower groundwater temperatures.

There is only one of our wells (Well 3) that has ever had temperatures in excess of 18 °C. From 2000 - 2003 there were three instances where the readings were above 14.0 °C out of a total of 18. The maximum temperature recorded during that time was 18.2 C. Interestingly, its overall average for that period is 13.9 °C. This well is scheduled for rehabilitation work and it is possible that these high anomalous temperature readings may not reoccur after this work is completed. Well 3 has no independent pump to waste line so its water is blended with that from other wells in the collection main before it is discharged. Therefore, it is most unlikely that water from this well (or any others in the Columbia South Shore Wellfield) would cause an adverse thermal impact to the waters ofthe Columbia Slough.

Outfall 001 and future Outfall 001-F discharge from the ground water system to the Columbia River, a water body that is classified as a Salmon and Steelhead Migration Corridor. The seven-day-average maximum temperature during the months of July and August for this classification is 20 °C. During the period of 2000 - 2003, temperature measurements from ground water have all been below 20 °C* Given the flow of the Columbia River and historical water temperatures of the discharges, we would not expect to see any measurable increase in river temperature as a result of Water Bureau discharges.

Discharges relating to the Bull Run conduits result from draining the conduits for inspection, maintenance, and repair. These discharges are infrequent: since 1997, there have been only four monthly Discharge Monitoring Reports for discharges from the conduits, all of which took place in the months of December or January. Portland Water Bureau Evaluation Report Page 8 of 23

The receiving water bodies for conduit discharges include the Bull Run River, Sandy River, and a number of small creeks and unnamed tributaries between the Sandy River and the western basin boundary. These water bodies are subject to various temperature criteria and standards. Except in emergencies, conduit discharges are scheduled to occur during cooler weather when demand is low and the system can safely operate even if one of the conduits is out of service. During that time, the conduits carry water that is below any temperature limits set for receiving waters. Given the rarity and seasonal nature of conduit discharges, we would not expect these discharges to have any significant thermal impacts on surface water bodies.

For the past few years, the Water Bureau has been working with DEQ, NOAA Fisheries, and the US Fish and Wildlife Service on temperature issues in the Bull Run River, especially during the summer months, as part of its Endangered Species Act and Clean Water Act compliance. Greg Geist of your office is the DEQ contact for this effort and has received a large amount of water temperature data from the Water Bureau.

Johnson Creek is the receiving water body for the drain and overflow lines from Powell Butte Reservoir (Outfall 005). The stream is classified as rearing habitat in July and August, with a temperature standard of 18 °C. Below the outfall, the creek is salmonid spawning habitat with a maximum temperature of 13 °C from October 15 to May 15. We understand, however, that Johnson Creek is often out of compliance with these numbers.

Powell Butte Reservoir water discharges are rare; there have been none over the past five years. The only discharges from this outfall during this time period have been site storm water runoff. Temperature data taken from water quality samples at Powell Butte over the period 1998 - 2003 show an average reservoir water temperature of 14.2 °C during the months of July and August with a maximum reading of 17.0 °C. Based on this information, it is unlikely that any discharges during these months (if they were to occur) would cause a temperature increase in Johnson Creek. Between November and May, reservoir water and, therefore, discharge temperatures would not exceed 13 °C. That leaves the second half of October to consider. Theoretically it is possible that a discharge from this location might exceed the 13 °C standard in the second half of October, Given the infrequency of discharges from this site, there is no reason to believe a discharge will occur at that time. To reduce even that theoretical risk, the Water Bureau will avoid any non emergency discharges of Powell Butte reservoir water during the spawning season if reservoir temperatures exceed the ambient temperature of Johnson Creek as measured at the Sycamore gauge. Portland Water Bureau Evaluation Report Page 9 of 23

To summarize, the Water Bureau does not expect that any non-emergency discharges under this permit will have an adverse thermal impact on waters of the State. Discharges from the conduits are rare and occur during cooler weather when temperature is not an issue. Groundwater system and Powell Butte Reservoir discharges are not likely to result in temperature increases in excess of the applicable limits and could, in some circumstances, actually cool the surface water temperatures.

POLLUTANTS DISCHARGED AND PROPOSED LIMITS

Pollutants of Concern The first step in developing a permit is to determine the pollutants of concern that need to be analyzed to conclude whether effluent limits are needed for those pollutants. The major sources of information for this step are the sampling data accumulated by the site. All ofthe discharges are potable water with or without added chlorine.

Technology-Based Effluent Limits 40 CFR 122.44(a) and (e) These limits are based on effluent limitations and standards promulgated under section 301 ofthe CWA, or new source performance standards promulgated under section 306 ofthe CWA, on case-by-case effluent limitations determined under section 402(a)(1) ofthe CWA, or a combination ofthe three in accordance with 40 CFR 125.3.

There are no effluent limitation guidelines for these discharges.

Water Quality-Based Effluent Limits 40 CFR 122.44(d) These limits are any requirements in addition to or more stringent than promulgated effluent limitations guidelines or standards under sections 301, 304, 306, 307, 318 and 405 ofthe CWA necessaiy to achieve water quality standards established under section 303 ofthe CWA, including State narrative criteria for water quality.

The Department or EPA has established water-quality based effluent limits for the following pollutants in the facility's wastewater. Based on the water chemistty data submitted with the current and previous applications, the Department set limits for reactive phosphorus and total chlorine residual. pH is set at a range of 6 to 9.

The Department is required to set effluent limits for pollutants that may be discharged at levels that cause, or have the reasonable potential to cause, an excursion above any numeric or narrative state water quality standard [40 CFR 122.44(d)(l)(i)]. When determining whether a discharge causes or has the reasonable potential to cause an instream excursion above a narrative or numeric State water quality standard, the Department must account for existing controls on point sources, the variability ofthe pollutant, and the dilution ofthe effluent in the receiving water. Portland Water Bureau Evaluation Report Page 10 of 23

340-041-004 Antidegradation Review In order to issue a permit, the Department must perform a review per the requirements of Oregon Administrative Rules, OAR 340-041-0004. The Department must determine that the discharge will not cause or contribute to any water quality violations before allowing a new mass load discharge. (This is a not a new or increased load, but the review is still useful. Below is a listing of the required findings and considerations, followed by the Department's conclusions. Numbered paragraphs are taken from the Oregon Administrative Rules.

(1) Purpose. The purpose ofthe Antidegradation Policy is to guide decisions that affect water quality such that unnecessary further degradation from new or increased point and nonpoint sources of pollution is prevented, and to protect, maintain, and enhance existing surface water quality to ensure the full protection of all existing beneficial uses. The standards and policies set forth in OAR 340-041-0007 through 340-041-0350 are intended to supplement the Antidegradation Policy.

Conclusion. The NPDES permit for the City of Portland's discharge is a permit renewal with no increase in discharged load. Permit renewals with the same discharge load as the previous permit are not considered to lower water quality from existing water quality. Thus, the Department finds that the discharge is not subject to an in-depth antidegradation review. (Antidegradation Policy Implementation Internal Management Directive for NPDES Permits and Section 401 Water Quality Certifications, ODEQ March 2001).Qx

(2) Growth Policy. In order to maintain the quality of waters in the State of Oregon, it is the general policy ofthe Commission to require that growth and development be accommodated by increased efficiency and effectiveness of waste treatment and control such that measurable future discharged waste loads from existing sources do not exceed presently allowed discharged loads except as provided in section (3) through (9) of this rule.

Conclusion. See the discussion above in the Facility Description and Update section.

(9)(a)(C) The new or increased discharged load will not unacceptably threaten or impair any recognized beneficial uses or adversely affect threatened or endangered species. In making this determination, the Commission or Department may rely upon the presumption that if the numeric criteria established to protect specific uses are met the beneficial uses they were designed to protect are protected. In making this determination the Commission or Department may also evaluate other State and federal agency data that would provide information on potential impacts to beneficial uses for which the numeric criteria have not been set. Portland Water Bureau Evaluation Report Page 11 of 23

Conclusion. The identified beneficial uses in the several receiving streams are as follows: public domestic water supply, private domestic water supply, industrial water supply, irrigation, livestock watering, anadromous fishpassage , salmonid fish rearing, salmonid fish spawning, resident fish and aquatic life, wildlife and hunting, fishing, boating, water contact recreation, aesthetic quality, and commercial navigation and transportation.

Based on the review summarized above, the Department believes that the continuing discharges of potable water will not unacceptably threaten or impair any recognized beneficial uses.

(9)(b) The activity, expansion or growth necessitating a new or increased discharge load is consistent with the acknowledged local land use plans as evidenced by a statement of land use 'compatibility fromth e appropriate local planning agency.

Conclusion. The Portland Bureau of Water Works is applying for renewal of an existing permit and is not seeking a new or increased discharge load. The Bureau of Water Works has filed land use compatibility statements with the Cities of Portland and Gresham, and the counties of Clackamas and Multnomah. They have been approved.

(9)(c) Oregon's water quality management policies and programs recognize that Oregon's water bodies have a finite capacity to assimilate waste. Unused assimilative capacity is an exceedingly valuable resource that enhances in-stream values and environmental quality in general. Allocation ofany unused assimilative capacity should be based on explicit criteria. In addition to the conditions in subsection (a) of this section, the Commission or Department may consider the following:

(A) Environmental Effects Criteria:

(i) Adverse Out-of-Stream Effects. There may be instances where the discharge or limited discharge alternatives may cause greater adverse environmental effects than the increased discharge alternative.

Conclusion. Not applicable to this situation.

(ii) instream Effects. Total stream loading may be reduced through elimination or reduction of other source discharges or through a reduction in seasonal discharge. A source that replaces other sources, accepts additional waste from less efficient treatment units or systems, or reduces discharge loadings during periods of low stream flow may be permitted an increased discharge load year-round or during seasons of high flow, so long as the loading has no adverse effect on threatened and endangered species; Portland Water Bureau Evaluation Report Page 12 of 23

Conclusion. Not applicable to this situation.

(iii) Beneficial Effects. Land application, upland wetlands application, or other nondischarge alternatives for appropriately treated wastewater may replenish groundwater levels and increase streamflow and assimilative capacity during otherwise low streamflow periods.

Conclusion. Not applicable to this situation.

(9)(c)(B) Economic Effects Criteria:

(i) Value of Assimilative Capacity. The assimilative capacity of Oregon's streams is finite, but the potential uses of this capacity are virtually unlimited. Thus it is important that priority be given to those beneficial uses that promise the greatest return (beneficial use) relative to the unused assimilative capacity that might be utilized. In-stream uses that benefit from reserve assimilative capacity, as well as potential future beneficial use, will be weighed against the economic benefit associated with increased loading.

Conclusion, The discharge will use variable but small percentages ofthe several receiving streams's flowrates. These discharges are not expected to use significant portions ofthe receiving streams's assimilative capacities.

(ii) Cost of Treatment Technology. The cost of improved treatment technology, nondischarge, and limited discharge alternatives may be evaluated.

Conclusion, The currently used technologies for potable water, including chlorination, chloramination, and UV treatment are appropriate.

As with all NPDES permits issued for facilities that propose to discharge wastewater to waters ofthe state, the proposed draft permit for the Portland Bureau of Water facility was drafted to ensure that all state wide water quality standards contained in OAR 340-041-0007 through 340-041-0053 and all basin-specific water quality standards would be achieved.

Each ofthe parameters listed is discussed below followed by the conclusions reached during this review.

340-041-0007 Statewide Narrative Criteria

(1) Notwithstanding the water quality standards contained in this Division, the highest and best practicable treatment and/or control of wastes, activities, and flows must in every Portland Water Bureau Evaluation Report Page 13 of 23 case be provided so as to maintain dissolved oxygen and overall water quality at the highest possible levels and water temperatures, coliform bacteria concentrations, dissolved chemical substances, toxic materials, radioactivity, turbidities, color, odor, and other deleterious factors at the lowest possible levels.

Conclusion. The proposed permit will meet these requirements.

(2) Where a less stringent natural condition of a water ofthe State exceeds the numeric criteria set out in this Division, the natural condition supersedes the numeric criteria and becomes the standard for that water body. However, there are special restrictions, described in OAR 340-041-0004(9)(a)(C)(iii), that may apply to discharges that affect dissolved oxygen.

Conclusion. There is no less stringent condition.

(11) Fungi.

Conclusion. All ofthe discharged waters are treated or untreated groundwater or surface water and are part of Portland's drinking water supply. The discharges are not expected to contain fungi or to promote their growth.

(12) Tastes, odors, or toxic or other conditions.

Conclusion. The discharges covered by this permit are not expected to create tastes or odors or toxic or other conditions deleterious to aquatic life or to affect potability of drinking water or palatability offish or shellfish

(13) Deposits.

Conclusion. All ofthe discharged waters are treated or untreated groundwater or surface water and are part of Portland's drinking water supply. The chemical analyses provided as part ofthe application show that discharges are not expected to contain material which would cause appreciable deposition in the river.

(14) and (15) Objectionable conditions and offensive aesthetic conditions.

Conclusion. The discharges covered by this permit are not expected to cause offensive aesthetic conditions.

(16) Radioisotopes. Portland Water Bureau Evaluation Report Page 14 of 23

Conclusion. No radioactive materials are used in the facility's processes. The facility's discharge is not expected to contain radioisotopes.

340-041-0009 Bacteria

Conclusion. There is no sewage connected with this discharge. The facility's discharge is not expected to contain bacteria.

340-041-0016 Dissolved Oxygen (1) Dissolved oxygen (DO): No wastes may be discharged and no activities must be conducted that either alone or in combination with other wastes or activities will cause violation ofthe following standards: The changes adopted by the Commission on January 11, 1996, become effective July 1,1996. Until that time, the requirements of this rule that were in effect on January 10, 1996, apply: (a) For water bodies identified as active spawning areas in the places and times indicated on the following Tables and Figures set out in OAR 340-041-0101 to OAR 340-041-0340: Tables 101B, 121B, 180B, 201B and 260B, and Figures 130B, 151B, 160B, 170B, 220B, 230B, 271B, 286B, 300B, 310B, 320B, and 340B, (as well as any active spawning area used by resident trout species), the following criteria apply during the applicable spawning through fry emergence periods set forth in the tables and figures: (A) The dissolved oxygen may not be less than 11.0 mg/l. However, if the minimum intergravel dissolved oxygen, measured as a spatial median, is 8.0 mg/i or greater, then the DO criterion is 9.0 mg/l; (B) Where conditions of barometric pressure, altitude, and temperature preclude attainment of the 11.0 mg/l or 9.0 mg/l criteria, dissolved oxygen levels must not be less than 95 percent of saturation; (C) The spatial median intergravel dissolved oxygen concentration must not fall below 8.0 mg/l. (b) For water bodies identified by the Department as providing cold-water aquatic life, the dissolved oxygen may not be less than 8.0 mg/l as an absolute minimum. Where conditions of barometric pressure, altitude, and temperature preclude attainment ofthe 8.0 mg/I, dissolved oxygen may not be less than 90 percent of saturation. At the discretion ofthe Department, when the Department determines that adequate information exists, the dissolved oxygen may not fall below 8.0 mg/l as a 30-day mean minimum, 6.5 mg/l as a seven-day minimum mean, and may not fall below 6.0 mg/l as an absolute minimum (Table 21); (c) For water bodies identified by the Department as providing cool-water aquatic life, the dissolved oxygen may not be less than 6.5 mg/I as an absolute minimum. At the discretion ofthe Department, when the Department determines that adequate information exists, the dissolved Portland Water Bureau Evaluation Report Page 15 of 23

oxygen may not fall below 6.5 mg/l as a 30-day mean minimum, 5.0 mg/l as a seven-day minimum mean, and may not fall below 4.0 mg/l as an absolute minimum (Table 21); (d) For water bodies identified by the Department as providing warm-water aquatic life, the dissolved oxygen may not be less than 5.5 mg/l as an absolute minimum. At the discretion ofthe Department, when the Department determines that adequate information exists, the dissolved oxygen may not fall below 5.5 mg/I as a 30-day mean minimum, and may not fall below 4.0 mg/l as an absolute minimum (Table 21); (e) For estuarine water, the dissolved oxygen concentrations may not be less than 6.5 mg/l (for coastal water bodies); (t) For ocean waters, no measurable reduction in dissolved oxygen concentration may be allowed.

Conclusion. Based on the regular analyses of Portland's drinking water, these discharges will not have a substantive BOD load.

340-041-0021 pH (1) Unless otherwise specified in OAR 340-041-0101 through 340-041-0350, pH values (Hydrogen ion concentrations) may not fall outside the following ranges: (a) Marine waters: 7.0 - 8.5; (b) Estuarine and fresh waters: 6.5 - 8.5. (2) Waters impounded by dams existing on January 1, 1996, which have pHs that exceed the criteria are not in violation ofthe standard, if the Department determines that the exceedance would not occur without the impoundment and that all practicable measures have been taken to bring the pH in the impounded waters into compliance with the criteria.

Willamette Basin (1) pH (hydrogen ion concentration). pH values may not fall outside the following ranges: (a) All basin waters (except main stem Columbia River and Cascade lakes): 6.5 to 8.5;

Conclusion. Based on a review ofthe discharge monitoring report data collected during the previous permit term, the proposed discharges covered by this permit may at times have a pH outside the range 6.5 - 8.5. The Bureau of Water Works provided the following discussion of their pH situation.

"Although the majority of our discharges have been within the pH range of 6.5 to 8.5 Standard Units (SU), there are occasions when our discharges have been outside that range. Portland Water Bureau Evaluation Report Page 16 of 23

Most of our discharges from the groundwater collection system consist of unchlorinated native groundwater. Unfortunately, a number of Troutdale Sandstone Aquifer (TSA) and Sand and Gravel Aquifer (SGA) wells experience excursions from the proposed limits. In the time period 2000 - 2003, seven wells have had one or more pH readings in excess of 8.5 SU. Eleven other wells have had one or more pH readings of 8.4 and 8.5 SU during this time. The Bureau currently has six wells screened in the TSA and thirteen wells screened in the SGA. Altogether pH for these wells averages between 8.0 and 8.6 SU. Based on the substantial data available on these wells, we would expect that water from these wells would exceed pH 8.5 SU (but never exceed pH 9.0 SU) only some of the time they were operating. Often water from these wells is blended with water from wells having lower pH values. However, there are currently six TSA and SGA wells having dedicated pump-to-waste lines (as required by regulations ofthe Department of Human Services) where blending does not occur. These pump-to-waste lines are operated independently ofthe groundwater collection system and are used to clear sand and casing water from the well before the well water is added to the drinking water supply system. The duration for this activity is usually brief and does not involve large quantities of water. Well exercising / testing is another activity where blending may not occur. The wells are operated individually in a sequential manner for about an hour each. This is a routine activity that is conducted two to three times a year. On the other end of the scale, pH of Bull Run water measured at the inlet to the Lusted Hill on the three conduits was less than 6.5 SU approximately 10 percent of the time from 1998 - 2004. This water is injected with gaseous chlorine for disinfection and pH tends to be lower than untreated Bull Run water by an average of 0.3 SU. The pH for native Bull Run water over the time period 2000 - 2003 had an average value of 7.0 SU, Dechlorinating agents employed by the Bureau are not expected to change the pH ofthe discharged water. pH adjustment is done at Lusted Hill and all water discharged from outfalls downstream of this facility is within the range of the proposed limits. Given that 6.5 SU is within the pH range of natural Bull Run surface water and that chlorination tends to slightly depress pH values, there is not a great margin of error available to avoid excursions of the proposed limits. Bull Run water is very poorly buffered (average alkalinity is 7.4 mg/L). As a consequence, pH measurements are difficult to take accurately. One can simply blow air over a sample and change a pH reading downward by a couple of tenths. The Bureau has to use special low ionic strength electrodes to accurately measure pH. In addition to having special equipment to measure pH for this water, it also takes a highly skilled operator to take an accurate reading. Portland Water Bureau Evaluation Report Page 17 of 23

The current end of pipe pH limitation of 6.0 to 9.0 SU has allowed the Bureau sufficient operating flexibility over the past twenty years to avoid the problems mentioned above. We wish to propose a solution that would maintain the current end of pipe limitation but also protect ambient water quality. This solution is to adopt a suitable mixing zone at those outfalls where there is the potential to be outside the proposed range at the end of the pipe. For these outfalls, the 6,5 to 8.5 SU pH limitation would apply at the edge of the mixing zone and the 6.0 to 9.0 SU limits would apply at the end of pipe. As you know, there is a precedent for this as the City's Columbia River outfall (Outfall 001) already has such a mixing zone. We would recommend that the following outfalls be considered for mixing zones: • "Outfall 001-A through 001-J, groundwater collection system. • Outfalls 002-Y through 002-AP, Conduit 2 Headworks to Lusted Hill. • -Outfalls 003-P through 003-AI, Conduit 3 Headworks to Lusted Hill. • Outfalls 004-N through 004-Z, Conduit 4 Headworks to Lusted Hill."

The Department has reviewed the Bureau's comments and has calculated that the amount of dilution available in the receiving streams is easily adequate to buffer the pH to being within water quality standards at the edge of a small mixing zone. The permit limits will be 6.0 to 9.0.

340-041-0028 Temperature

(4) Biologically Based Numeric Criteria. Unless superseded by the natural conditions criteria described in section (8) of this rule, or by subsequently adopted site-specific criteria approved by EPA, the temperature criteria for State waters supporting salmonid fishes are as follows:

(a) The seven-day-average maximum temperature of a stream identified as having salmon and steelhead spawning use on subbasin maps and tables set out in OAR 340-041-0101 to OAR 340- 041-0340: Tables 101B, and 121B, and Figures 130B, 151B, 160B, 170B, 220B, 230B, 271B, 286B, 300B, 310B, 320B, and 340B, may not exceed 13.0 degrees Celsius (55.4 degrees Fahrenheit) at the times indicated on these maps and tables;

(c) The seven-day-average maximum temperature of a stream identified as having salmon and trout rearing and migration use on subbasin maps set out at OAR 340-041-0101 to OAR 340- 041-0340: Figures 130A, 151A, 160A, 170A, 220A, 230A, 271A, 286A, 300A, 310A, 320A, and 340A, may not exceed 18.0 degrees Celsius (64.4 degrees Fahrenheit);

(d) The seven-day-average maximum temperature of a stream identified as having a migration corridor use on subbasin maps and tables OAR 340-041-0101 to OAR 340-041-0340: Tables Portland Water Bureau Evaluation Report Page 18 of 23

101B, and 121B, and Figures 151A, 170A, and 340A, may not exceed 20.0 degrees Celsius (68.0 degrees Fahrenheit). In addition, these water bodies must have coldwater refugia that's sufficiently distributed so as to allow salmon and steelhead migration without significant adverse effects from higher water temperatures elsewhere in the water body. Finally, the seasonal thermal pattern in Columbia and Snake Rivers must reflect the natural seasonal thermal pattern; (8) Natural Conditions Criteria. Where the department determines that the natural thermal potential of all or a portion of a water body exceeds the biologically-based criteria in section (4) of this rule, the natural thermal potential temperatures supersede the biologically-based criteria, and are deemed to be the applicable temperature criteria for that water body.

Conclusion. Based on a review of monthly discharge monitoring reports, there is no reasonable potential for any ofthe water discharged under this permit will cause a measurable increase in surface water temperature. Typical long term average discharge temperatures are around 14 °C.

340-041-0031 Total Dissolved Gas. (1) Waters will be free from dissolved gases, such as carbon dioxide hydrogen sulfide, or other gases, in sufficient quantities to cause objectionable odors or to be deleterious to fish or other aquatic life, navigation, recreation, or other reasonable uses made of such water

Conclusion. Water cascading over dams commonly entrains air to a supersaturated level. Elevated TDG can cause gas bubble disease in aquatic organisms. There is no gas used or generated at this facility. The discharges covered by this permit are not expected to cause increases of dissolved gases in sufficient quantities to cause objectionable odors or to be deleterious to fish or other aquatic life, navigation, recreation, or other reasonable uses made ofthe receiving water.

340-041-0032 Total Dissolved Solids The concentrations listed below may not be exceeded unless otherwise specifically authorized by DEQ upon such conditions as it may deem necessaiy: All Fresh Water Streams and Tributaries - 100 mg/L.

340-041-0345 (2) Willamette Basin. Total Dissolved Solids. Guide concentrations listed may not be exceeded unless otherwise specifically authorized by DEQ upon such conditions as it may deem necessary to carry out the general intent of this plan and to protect the beneficial uses set forth in OAR 340-041-0340: Willamette River and Tributaries —100.0 mg/l.

340-041-0104 Water Quality Standards and Policies Specific to the Main Stem Columbia River Portland Water Bureau Evaluation Report Page 19 of 23

(2) Total Dissolved Solids. Guide concentrations listed below must not be exceeded unless otherwise specifically authorized by DEQ upon such conditions as it may deem necessary to carry out the general intent of this plan and to protect the beneficial uses set forth in OAR 340- 041-0101:

(b) All other river miles of main stem Columbia River ~ 500.0 mg/l. Conclusion. Based on the August 2006 Triannual Water Quality Analysis of Portland's drinking water supply, treated water has TDS concentrations in the range of 20 to 200 mg/L.

340-041-0033 Toxic Substances

(1) Toxic substances may not be introduced above natural background levels in the waters ofthe State in amounts, concentrations, or combinations that may be harmful, may chemically change to harmful forms in the environment, or may accumulate in sediments or bioaccumulate in aquatic life or wildlife to levels that adversely affect public health, safety or welfare, aquatic life, wildlife, or other designated beneficial uses;

(2) Levels of toxic substances in waters ofthe state may not exceed the criteria listed in Tables 20, 33A, and 33B.

Many toxic substances have limits set in OAR 340-041-Table 20. When appropriate, these limits are explicitly stated in NPDES permits. Some toxics are explicitly dealt with in promulgated TMDLs. See discussion below. The Reasonable Potential Analysis Spreadsheet is appended to this evaluation.

(a) Each value for criteria in Table 20 is effective until the corresponding value in Tables 33A or 33B becomes effective.

(A) Each value in Table 33 A is effective on February 15, 2005, unless EPA has disapproved the value before that date. If a value is subsequently disapproved, any corresponding value in Table 20 becomes effective immediately. Values that are the same in Tables 20 and 33A remain in effect.

(B) Each value in Table 33B is effective on EPA approval.

Conclusion. All ofthe discharged waters are treated or untreated groundwater or surface water and are part of Portland's drinking water supply. The discharges covered under this pennit are not expected to contain toxic substances exceeding applicable water quality standards.

340-041-0036 Turbidity Turbidity (Nephelometric Turbidity Units, NTU): No more than a ten percent cumulative increase in natural stream turbidities shall be allowed, as measured relative to a control point immediately upstream ofthe turbidity causing activity.

Conclusion. Based on a review ofthe discharge monitoring report data collected during the previous permit term, the proposed discharges covered by this permit are not expected to affect instream turbidity.

340-041-0046 Water Quality Limited Waters

(5) For water bodies designated as water quality limited under sub-section (b) ofthe definition of "Water Quality Limited" in OAR 340-041-0002, requests for load increases may be considered using the process set out in OAR 340-041-0004(9)(b) of this rule.

Conclusion: The Columbia River is listed as water quality limited for the following parameters:

Temperature Summer DPR Year P0B Around Polynuciear Aromatic Year Hydrocarbons Around DDT Metabolite (DDE) ;' ^^ Year Arsenic Around

The Willamette River is water quality limited for the following parameters.

Fecal Coliform Winter/Spring/Fall Dieldrin Year Around DDT Year Around DDT Metabolite (DDE) Year Around Biological Criteria Portland Water Bureau Evaluation Report Page 21 of 23

Mercury Year Around Aldrin Year Around Temperature Summer PCB Year Around DDT Year Around Manganese Year Around Iron Year Around Pentachlorophenol

The Columbia Slough is water quality limited for the following parameters.

Temperature Spring/Summer/Fail Iron Year Around Manganese Year Around Iron Year Around Manganese Year Around

Fairview Lake/Osborn Creek is water quality limited for the following parameter:

pH October 1 -May31

Conclusion: The discharges covered by this permit are not expected to cause or contribute to exceedances for any ofthe above listed parameters.

340-041-0344 Approved TMDLs in the Basin:

The following TMDLs have been approved for the Columbia River.

Dioxin (2,3,7,8- TCDD) Dioxin (2,3,7,8- TCDD) r Total Dissolved Gas ^u nd

The following TMDLs have been approved for the Willamette River.

Dioxin (2,3,7,8-TCDD)

The following TMDLs have been approved for the Columbia Slough. Portland Water Bureau Evaluation Report Page 22 of 23

Chlorophyll a Spring/Summer/Fall Phosphorus Spring/Summer/Fail PH Spring/Summer/Fall Dioxin (2,3,7,8- TCDD) Lead PCB Fecal Coliform Summer DDT Metabolite (DDE) Fecal Coliform Winter/Spring/Fall Dissolved Oxygen Year Around

Conclusion: The discharges covered by this permit are not expected to cause or contribute to exceedances for any ofthe above listed parameters.

340-041-0053 Mixing Zones

(1) The Department may allow a designated portion of a receiving water to serve as a zone of dilution for wastewaters and receiving waters to mix thoroughly and this zone will be defined as a mixing zone;

Conclusion. See discussion above in the pH section. This permit continues the regulatory mixing zones (RMZ) with the following dimensions established at the last renewal:

The allowable mixing zone for Outfall 001 shall consist of that portion ofthe Columbia River not to exceed a 50 meter radius from the point of discharge. Pursuant to OAR 340- 041-0053(2)(a)(A) a Zone of Immediate Dilution (ZID) is established within the mixing zone and shall consist of that portion ofthe Columbia River not to exceed a 30 meter radius from the point of discharge.

Additional mixing zones have been established for the following locations. The mixing zones shall consist of those portions ofthe receiving streams not to exceed 25% ofthe stream width from the points of discharge.

Outfall 001-A through 001-J, groundwater collection system. Outfalls 002-Y through 002-AP, Conduit 2 Headworks to Lusted Hill. Outfalls 003-P through 003-AI, Conduit 3 Headworks to Lusted Hill. Outfalls 004-N through 004-Z, Conduit 4 Headworks to Lusted Hill. Outfalls 005, 005-L through N Portland Water Bureau Evaluation Report Page 23 of 23

COMPLIANCE HISTORY

May 2003. Notice of Noncompliance for accidental discharge.

PROPOSED PERMIT

The permit will be nearly identical to the current permit with the addition ofthe 2005 permit modification and the Sandy River Crossing Conduit. The proposed permit is attached.