Cosumnes power plant (01-afc-19) data response, set 1A
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APPLICANT’S CLARIFICATION TO BACKGROUND STATEMENTSThe Background improperly relies upon State Water Resources Control Board (“State Board”) Resolution No. 75-58 as being applicable in this context. Resolution 75-58 discourages the use of fresh water for industrial processes, instead encouraging the use of recycled water. However, Resolution 75-58 applies to applications before the State Board only in two particular situations: (i) when an applicant has applied for a new water right, or to change the place of use, point of diversion, or purpose of use of an existing water right; and (ii) when an applicant has applied for a permit to discharge water. Here, SMUD does not need to apply to the State Board for a new water right (or for a change in place or use, purpose of use, or point of diversion) because SMUD holds the existing entitlements to water needed for this project. Therefore, as a new right is not being requested, and as no permissions from the State Board are needed in order to utilize the existing entitlements, the policy of Resolution 75-58 which discourages the issuance of new rights for the use of fresh water does not apply in this case. And while SMUD does need to apply for and receive a discharge permit to discharge effluent, only the discharge portions of Resolution 75-58 are applicable. It is also important to note that the policies behind Resolution 75-58 do not apply in this case. Those two policies are (i) to ensure adequate fresh water supplies for irrigation, and (ii) to ensure adequate Delta flows. In the case of the Cosumnes Power Plant, the cooling water discharged from the Plant is used by downstream irrigators under contract. And after these irrigators have used the water it flows further downstream where it is discharged into the Delta. Thus, the policy reasons behind Resolution 75-58's discouragement of the use of fresh water for industrial processes do not apply in this case. The Background also states that SMUD “does not yet have a U.S. Bureau of Reclamation (USBR) contract for Central Valley Project (CVP) water after 2012 . . and thus availability is not yet assured for the life of CPP.” It is true that SMUD’s existing contract expires in 2012. However, federal law mandates that the USBR must renew that contract at SMUD’s request. See Act of June 21, 1963, § 1, Pub.L.No. 88-44, 77 Stat. 68. In addition, this right of continual renewal has been recognized by the USBR in the draft renewal contract currently under negotiation between SMUD and the USBR. (Copy available from SMUD or USBR). Lastly, a “Water Needs Analysis” conducted by the USBR has confirmed that SMUD has the need for the water entitlements held under its contract, and thus that the water is available in a renewal contract with USBR. Thus, the availability of the CVP water is assured for the life of the CPP. The Background also relies upon California Water Code Section 13550 for justification for an assessment of alternatives. Section 13550 is inapplicable to CPP, as the water taken from the Folsom-South Canal and used for cooling purposes (and the boiler cycle) is not potable water. Rather, it is high quality raw water that has not been treated for potable uses. data Request
a) The use of treated wastewater from the GWTP and SRWTP; Response: SRWTP is approximately 26 miles and GWTP is approximately 12 miles from CPP, requiring substantial infrastructure to deliver and treat at an increased cost. While SRWTP would have suitable volume to supply CPP, SRWTP is currently not a purveyor of water and the quality, reliability, and availability of treated wastewater is uncertain. GWTP may not provide suitable volume to CPP under certain conditions, and would be an unreliable source. The use of wastewater for cooling has implications for waste management, in that disposal would not be possible in the vicinity of the project, without substantial treatment and cost. Additions to plant infrastructure would most likely be required to treat both supply and discharge water. It is likely that water consumption would increase from use of this lower quality water. Due to the parasitic loads of additional equipment, a drop in plant efficiency would be expected. b) Drilling an onsite supply well; Response: Ground water using an onsite supply well was dismissed as an alternative for CPP. AFC section 9.2.2.3.14 Water Resources, briefly discusses the overdraft or near-overdraft condition of groundwater in Sacramento County. AFC section 8.14.3.2 discusses groundwater conditions in detail. According to a 1994 SMUD study, it was found that groundwater levels near the proposed CPP have been dropping approximately 2 feet per year since 1976, with potable water at depths of 230 to 350 feet. This area is considered by Sacramento County to be in one of the three major problem areas for groundwater overdraft in the county. Recharge areas usually exist along active significant stream channels with sands and gravels. Only limited areas near the Rancho Seco property have moderate recharge capability, and most of the site is characterized as having poor recharge capability because of clay or hardpan soils. Due to these conditions, study in the use of an onsite supply well for groundwater was not pursued. c) Imported brackish or irrigation return water; Response: The nearest supply of brackish water to the proposed project site would be near Antioch, more than 50 miles west of the project, requiring substantial additional linears facilities and plant infrastructure to deliver and treat. The resulting waste product would similarly require transport at least 50 miles for disposal. Flood irrigation of the type that yields irrigation return water is not common in the project vicinity. The nearest source of substantial return water would probably be in the vicinity of Lodi, at least 20 miles west of the project site. The supply would be highly variable in quality and seasonal in availability. Disposal of the irrigation return water would have the same limitations as brackish water, in that disposal would not be possible in the vicinity of the project, without substantial treatment. The additional costs, chemicals and energy consumption of treatment and pumping, and use of brackish water is unattractive when compared to the CVP and non-CVP water conveyed by USBR through the Folsom South Canal. d) Hybrid wet-dry cooling or spray-enhanced dry cooling (to reduce make-up water by at least 25 to 50%); Response: Although alternative cooling technologies such as dry and wet/dry cooling may be technically feasible, they represent a substantial economic penalty for the CPP. The District’s ability to provide clean, reliable, and highly competitive source of energy for the District ratepayers, relies on the ability of the CPP to remain cost efficient. The “wet/dry” cooling alternative includes a cooling tower/surface condenser system operated in parallel with an air-cooled condenser. The concept is that during cooler weather, the air-cooled condenser could perform the majority of the cooling thus conserving water. During hot weather, the cooling tower could perform the majority of the cooling, thus achieving a lower steam turbine exhaust pressure and therefore a greater plant output than would have been achievable using an air-cooled condenser alone. The “wet/dry” cooling system is most appropriate for plants where there is sufficient water available during hot weather, but where there is a limited supply on an overall annual use basis (e.g. a limited groundwater resource). Since the CPP proposes to use surface water that would intuitively be available in greater quantities during cool weather seasons than it would during hot weather, this alternative was not considered further. Previous Evaluations“Dry” and “wet/dry” cooling alternatives for power plants have been extensively evaluated prior to CPP. Previous studies concluded that the life cycle cost for “dry” cooling is at least twice that of “wet” cooling. The primary reason is the much higher capital cost for the air cooled condenser. The construction cost alone for air cooled condenser is six times greater than for cooling towers. For wet/dry cooling, previous studies have shown that the life cycle costs are less dramatic but still quite significant, i.e., at least 50 percent greater. A capital cost comparison was recently conducted for the proposed 560 MW Rio Linda/Elverta Power Project. This comparison showed that the installed cost for dry cooling was 2.3 times the cost for wet cooling. For wet/dry cooling, the installed cost was 1.8 times greater than wet cooling. Operating costs for “dry” and “wet/dry” cooling systems are significantly higher due to decreased efficiencies and higher parasitic loads. These operating inefficiencies are greatest in the summer when the demand for efficient plant operation (and the subsequent loss of revenue) is the greatest. Operational cost increases for dry cooling due to thermodynamic inefficiencies, increases in heat rate, and fuel costs are substantial, and could amount to more than $200 million over the life of the plant. A life cycle cost evaluation of dry and wet/dry cooling alternatives was conducted in 1998 for a similar project, the 700 MW High Desert Power Project (HDPP). The HDPP’s conclusions were that the capital cost to use dry or wet/dry cooling was 100 percent and 50 percent higher than wet cooling, respectively. The life cycle costs to use dry cooling were over 5.1 times higher than wet cooling and 3.9 times higher for wet/dry cooling. “Dry” or “wet/dry” cooling alternatives have actually been employed at other power plants but these are generally much smaller plants than the proposed CPP. The substantial increase in natural gas consumption due to inefficiency on peak temperature days makes this a substantial financial burden to the ratepayer. ConclusionAlthough dry cooling is technically feasible for CPP, it is undesirable both economically and visually. Notably it also defeats the high power density design (which holds promise for reducing the number of new energy facilities needed in California) by decreasing power output most at those times when California most needs power: hot summer days. Air cooled condensers consume about twice the area of wet cooling towers and noise emissions are slightly higher than wet cooling towers. In addition, their larger, bulkier profile is a permanent visual impact that may not integrate well into the overall landscape pattern. e) Wastewater zero-discharge; and, Response: Implementation of a zero-discharge system would reduce water use by CPP. Zero discharge systems require a concentration unit, crystallizer and or drum drier to reduce all liquids to a solid or semi-solid state. Concentration is achieved by using heat and energy from the plant and thus introduces a parasitic load that reduces overall efficiency. The waste product from the crystallizer then needs to be collected and disposed, generally by large trucks to a landfill or other suitable facility. Additional chemicals would be used to flocculate and crystallize wastewater, resulting in additional storage, management, transport and disposal. Crystallizers are tall structures that would contribute to the visual impact of the facility. The additional capital and operating costs affect the cost-efficiency of the plant, to which the District is responsible for its ratepayers. That is, the cost of producing energy would then be higher and the added cost would come from the people in Sacramento and surrounding areas. The long-term availability of waste disposal capacity may be affected by this additional generation of waste material. Secondly, the implementation of zero-discharge would deprive waters downstream of CPP, including Clay Creek, Hadselville, Laguna and the Cosumnes River of the beneficial uses of water from CPP. These streams were historically ephemeral, but additional diversions from the Cosumnes River have left it dry through much of the summer. The drinking-water quality water discharged from CPP to Clay Creek would be available to support agricultural, irrigation, fish and wildlife habitat and other uses in the watershed, and contribute to sustaining flows through the Cosumnes River during summer months. From the Cosumnes water would flow into the Delta. Zero discharge would effectively consume this water without further beneficial use. f) Recovery of water from cooling tower blowdown by use of reverse osmosis (RO), evaporator, direct osmosis, or other concentration process. Response: Reverse osmosis requires water to be pressurized to pass through a membrane, leaving a concentrated brine as a waste product. The cost of pumping and pressurizing water considered in conjunction with the need to dispose of a concentrated brine waste makes this an expensive technology, primarily suited to locations where brine waste disposal is easy (coastal or near underground salt domes, for example). To polish water suitable for discharge, a combination of RO and Ion Exchange (IX) might be necessary. IX requires acid and other chemicals to regenerate the column, resulting in additional chemical management and disposal costs. RO is generally acceptable for small volumes, but is not competitive for larger amounts of water. Also RO has a relatively high requirement for maintenance, as membranes are sensitive to entrained silica and other materials. General costs of RO treatment are estimated to be between $1.5 and $2.5 per 1,000 gallons of water at 480 ppm TDS. This additional cost would need to be paid by the ratepayers of the District and would not meet the objectives of the District to provide clean, reliable energy at the lowest cost.
Data and results should also be summarized and presented in tabular form. Response: Data Request 112 is essentially a listing of discussion items to be considered in the response to Data Request 111. Please see the various responses to Data Request 111 for a discussion of alternative water sources. Due to the length and breadth of the topic covered, and the variety of layouts and operating parameters for each alternate, there is not a concise way to extract and tabulate text and data that would serve a meaningful comparison. The Applicant asks that the entire context of the responses in 111 be considered, as each alternate has unique measures that are not easily conveyed in tabular form.
Response: Based on existing water quality data, we believe cycles will be limited by total dissolved solids limitations in blowdown. The RWQCB has generally required 500 ppm discharge limit. With intake water between 40 and 50 ppm, this would allow up to 10 cycles of concentration. In practical terms, trace metals in makeup water will probably require the cycling concentration to be lower. Scale inhibitors and other potential chemical treatments are listed in Table 8.12-2 of the AFC. It lists specifically Nalco 8306 Plus, or Sodium tolytriazole. The specific chemicals that would be used are determined based on operating conditions and cost, but should be similar. As noted, the tower is not expected to operate above 10 cycles, and at less than 10 cycles the chemicals that would be added are the same as listed.
Response: Silica occurs in dissolved and colloidal forms, depending on temperature and pH. Water quality tests did not attempt to segregate the forms. It is not known what the projected SDI is. It is not anticipated that either of these parameters will limit water use. The RO system has not been designed yet and chemicals that may be added have not yet been determined. As shown in Figure 2.2-6, a low volume of RO reject is cycled into the cooling tower system.
Response: As noted in Section 7.1, SMUD has a contract with the USBR to deliver up to 75,000 AFY of CVP and non-CVP water, of which only a small part is required for this project and the RSP facility. CPP is projected to use approximately 8,000 AFY, and RSP currently uses approximately 14,000 AFY. Combined these values do not approach the 75,000 AFY under contract with the USBR. Water use by RSP is expected to decrease after decommissioning, and therefore would not compete significantly with CPP. The 1,750 shown in Table 8.14-2 is listed in the requirements of the County of Sacramento, and does not directly affect how the USBR distributes and allocates CVP water under its authority. The cited LORS would guide when and whether the County diverts water and would have no affect on USBR’s deliveries of water to CPP.
Response: SMUD has received a “Will-Serve” letter from the USBR dated November 26, 2001 (copy attached as Attachment W&SR-116). In the letter, USBR confirms contract delivery of up to 60,000 acre-feet of water per year from Reclamation’s Central Valley Project and approximately 15,000 AFY of non-CVP water via the Folsom-South Canal. The letter states, “Reclamation law provides for successive renewals of water supply contracts for municipal and industrial water (Act of June 21, 1963, P.L. 88-44, 77 Stat. 68).” Furthermore, the letter states, “Given that the current use from all sources at Rancho Seco is less than 17,000 AFY, sufficient water remains within SMUD’s contract entitlement, as it exists and as it will be renewed, to support the additional 8,000 AFY projected for use by the new facility, assuming all other contract terms are met.” From this correspondence, it appears clear that the USBR feels there is sufficient water to meet current uses and the projected needs of CPP. While SMUD believes the possibility that an augmented or substitute supply will be needed is extremely remote, state and federal law provide for short- and long-term water transfers and assignments, alternatives that could be pursued, if necessary.
Response: There are four parts to the question. Responses are provided with the letters A through D, corresponding to the parts of the question. A) Projected water demand is the same for 40 years. A rate of 1638 gpm is projected for Phase 1 and 1638 gpm is projected for Phase 2, with the same number of operators and the same operating conditions. If water quality degrades, the use could go up; however, the degradation, and therefore, any use adjustment is not predictable. (Note: This response does not address SMUD’s water uses for its administrative headquarters, corporate yard or other non-generation facilities nor does it address water used to support generation at other generation sites, e.g., SMUD’s Upper American River Project in El Dorado County or Campbell Soup Company, because there is no link or relevancy to the source of water proposed for the CPP. B) SMUD has received a “Will-Serve” letter from the USBR dated November 26, 2001. In the letter, USBR confirms contract delivery of up to 60,000 acre-feet of water per year from Reclamation’s Central Valley Project and approximately 15,000 AFY of non-CVP water via the Folsom-South Canal. The letter states, “Reclamation law provides for successive renewals of water supply contracts for municipal and industrial water (Act of June 21, 1963, P.L. 88-44, 77 Stat. 68).” Furthermore, the letter states, “Given that the current use from all sources at Rancho Seco is less than 17,000 AFY, sufficient water remains within SMUD’s contract entitlement, as it exists and as it will be renewed, to support the additional 8,000 AFY projected for use by the new facility, assuming all other contract terms are met.” This correspondence clearly indicates two things: i) that the USBR will renew the contract as required by Federal Law; and the USBR contract provides sufficient water to meet current uses and the projected needs of CPP. As previously stated, the current contract will be in force through 2012; SMUD is not aware of any set of circumstances that would prevent renewal before expiration of the contract, and an early renewal process for all CVP contractors, including SMUD, is presently in progress. C) SMUD understands “7Q10” to mean seven-day low-flow with 10-year recurrence. USBR recently published its draft shortage policy in the Federal Register. Under the shortage policy, deliveries of municipal and industrial (M&I) water (SMUD's use is a M&I use) are not reduced until irrigation deliveries are reduced to 75%; then M&I deliveries and Irrigation deliveries are reduced by equal percentages until M&I deliveries are at 75% of historic use adjusted for growth and irrigation deliveries are at 50%. Irrigation deliveries are then reduced to 25% while M&I deliveries remain at 75%. M&I deliveries are never reduced below public health and safety requirements. It is inconceivable that, under this policy, deliveries of CVP water to Rancho Seco will ever be significantly curtailed: (1) CVP-wide irrigation deliveries have never been reduced to 25%; thus, based on history, deliveries to SMUD would never be reduced below 75% of historic use adjusted for growth; and (2) in any event, use of water for electric generation probably comes within the policy's provision that deliveries for public health and safety requirements will always be met. Moreover, it is important to recognize that Reclamation has never failed to supply water to its M&I water contractors. Therefore, the possibility of SMUD receiving no CVP water is extremely remote. Assuming arguendo that CVP water became unavailable, delivery of SMUD’s non-CVP water to the site under the Reclamation contract is not dependent on CVP water availability nor is it subject to application of Reclamation shortage provisions. Thus, SMUD could rely on its non-CVP supply to meet plant needs if no CVP water were available. SMUD could also explore short-term water transfers from other water rights holders. In the very unlikely event that SMUD’s water demand could not be met by any of these resources, it may be necessary to shut the plant down temporarily. D) Clay Creek was an ephemeral stream prior to construction of the Rancho Seco Plant (RSP). Discharge from RSP under NPDES permit has resulted in year around flows in Clay Creek, which in turn supplies Hadselville Creek, Laguna Creek and the Cosumnes River. Future flows due to RSP discharge are speculative upon NRC requirements and other governing bodies as decommissioning continues at RSP. CPP proposes to discharge to Clay Creek under NPDES permit. This discharge will supplement the current flow volume of the affected waterways during CPP plant operation and cease during periods of non-operation. Since USBR has produced a will-serve letter indicating sufficient water for CPP and RSP via the Folsom-South Canal, no impact to the waterways is expected other than described here. BACKGROUND Construction of the CPP may induce water and wind erosion at the power plant site. Surface water runoff is to be directed around the construction site to minimize erosion and pollutant loading. A Storm Water Pollution Prevention Plan (SWPPP) will be required for construction. The AFC (Pages 8.14.15 and 8.14.16) states that approximately 50 acres of land will be graded, plus approximately 20 acres of land used as a laydown area. The laydown area is described as including ephemeral streams that would have to be crossed in some manner. It is stated that a SWPPP will be provided to the County and will describe mitigation measures to avoid or minimize erosion and sedimentation to a level less than significant. Typical Best Management Practices (BMPs) are described in the AFC, particularly in Section 8.9.5, but few are specific to the CPP site. DATA REQUEST
Response: This question will be responded to on February 4, 2002.
Response: This question will be responded to on February 4, 2002.
Response: Sacramento County Public Works Agency has not specifically been consulted at this time regarding the proposed grading plan and storm water facilities. However, the Sacramento County Planning and Community Development Department has reviewed the AFC for conformance to general County Ordinances. As summarized in AFC Table 8.14-9, grading plan and storm water permit applications will be filed with the County 90 days prior to construction. In addition, a Construction Activity NPDES Stormwater and General Industrial Stormwater Permit application will be filed with the Regional Water Quality Control Board 90 days prior to construction. The information necessary to submit a grading and stormwater permit application will be developed during the detail-engineering phase. This information is expected to be available in August 2002. BACKGROUND Section 8.14.5.1 of the AFC states that stormwater that falls within the developed CPP site during construction and operation may potentially dissolve oils, grease, and other contaminants and carry them along with entrained sediments into Clay Creek. A Notice of Intent (NOI) is required to demonstrate compliance with the General Permit for Discharges of Storm Water Associated With Industrial Activities. The NOI will include a SWPPP that describes BMPs that will be used to reduce industrial stormwater contamination. Section 8.14.5.1 of the AFC describes the detention basin as a BMP, but there is no single description of all BMPs that would be included in the NOI. Since there is a potential for stormwater contamination, staff needs a description of: potential sources of contamination; receiving waters; management practices intended to prevent or minimize contamination; and probable effect of BMPs on reducing contamination that are outside the NPDES process. DATA REQUEST
Response: This question will be responded to on February 4, 2002.
Additional measures may be needed to meet special Inland Surface Waters Plan requirements. Response: This question will be responded to on February 4, 2002. BACKGROUND AFC Section 8.14.3.1 states that perennial flow in Clay Creek originates west of the CPP site where wastewater from the Rancho Seco Plant discharges into Clay Creek at the rate of approximately 20 cfs (13 mgd). This discharge contains irrigation runoff, processed radioactive water, treated wastewater, and heating tower blowdown. Dilution water is added from the Folsom-South Canal, but the total Clay Creek discharge is not given. Clay Creek flows into Hadselville Creek, which flows into Laguna Creek, which flows into the Cosumnes River. The Cosumnes River is described as flowing 2,000 cfs most of the year, but flows in the other creeks are not given. The proposed CPP will introduce another 3.6 cfs of cooling tower blowdown and stormwater (on average) into Clay Creek, increasing Clay Creek discharge by approximately 20% (not including dilution water). The effect of this additional discharge on Laguna and Hadselville Creeks is not known nor is the resulting effect on overall water quality known for those creeks. DATA REQUEST
BACKGROUND Portions of Clay Creek, Hadselville Creek, Laguna Creek and the Cosumnes River may be effluent-dependent water bodies managed under RWQCB’s Inland Surface Waters Plan. Section 8.14.3.1 states that the proposed CPP surface discharge has the potential to impact in-stream and water supply beneficial uses including industrial, agricultural, and municipal water supply; groundwater recharge; freshwater replenishment; aesthetic enjoyment; recreation; preservation and enhancement of fish, wildlife, and other aquatic resources including threatened and endangered species (Chinook Salmon and Delta Smelt). The NPDES permitting process can be lengthy and specific water quality objectives have not yet been established. Additionally, the RWQCB has indicated that effluent discharge criteria could be “very stringent” after incorporating allowances for long-term and indirect impacts such as bioaccumulation and carcinogenicity on threatened and endangered species and potential drinking water uses. With yet-to-be-defined “very stringent” discharge criteria, it is prudent to consider available alternatives. A conservative assessment of alternatives is needed to find the most effective method to meet the expected “very stringent” discharge requirements. DATA REQUESTS
Response: The RWQCB retains the authority to modify the Basin Plan, which determines beneficial uses. It is not SMUD’s intent at this time to request for any changes in beneficial use designations.
Response: The RWQCB retains the authority to determine water quality objectives, based on scientific data and the Basin Plan. Generally the background water quality is not a consideration except with respect to temperature and pH. Since Clay Creek is an effluent dominated water body, RSP runoff and effluent determines the water quality approximately 6 months a year. Background water quality parameters are established in the NPDES permit by requiring sampling at an upstream location (R1) when flow is present. Background parameters will likely be unaffected by changes at RSP.
Response: The RWQCB retains the authority to determine water quality objectives, based on scientific data and the Basin Plan. The Basin Plan includes designations for warm and cold water fish habitat that will probably apply to the receiving waters of Hadselville and Laguna creeks. The RWQCB does adjust objectives and standards seasonally as appropriate. Stormwater standards are established by the SWRCB and implemented by the RWQCB according to regulations in 40 CFR122.26. The Applicant does not have a role in determining the standards.
Response: The Applicant is not in the position to define water quality objectives, TMDL EDW or UAAs, as the authority rests with RWQCB. The RWQCB may use any or all of these sources. The Inland Surface Waters Plan and current EDW policy are available for download at: http://www.swrcb.ca.gov/rwqcb5/available_documents/index.html.
Response: The RWQCB retains the authority to determine water quality objectives, based on scientific data and the Basin Plan. Table 8.14-3 contains the constituents that CPP expects could be monitored. The RWQCB uses averaging periods ranging from daily to monthly or annual. These implementation measures, as well as monitoring and reporting are described in detail in the NPDES permit issued by the RWQCB. CPP does not feel it can speculate on what the RWQCB staff will determine.
Response: Guidelines for water quality criteria used by the RWQCB include EPA Chronic and Acute Aquatic life criteria which are developed based on the most sensitive aquatic organisms, and the most sensitive toxic endpoint (reproduction, survival, etc.) The RWQCB staff also reviews criteria for carcinogenicity, as implemented by the drinking water standards. The RWQCB generally requires 3-species chronic toxicity testing for a period of at least a year as part of the NPDES permit.
BACKGROUND Section 8.14.5.1 of the AFC describes a detention basin intended to maintain post-development discharges from the CPP at pre-development levels. According to the Data Adequacy Supplement dated November 13, 2001, the detention basin would be designed for a volume equal to the difference between the pre-development and post-development 10-year, 24-hour flood volumes, or 100,000 cubic yards of water. It is presumed that this is an error, and that the actual design volume is 100,000 cubic feet, which would be consistent with the difference in ten-year flow volume between AFC tables 8.14-6 and 8.14-7. According to the AFC Supplement, the detention basin design, which would include an oil/sediment separator, would be consistent with Bay Area Stormwater Management Agencies Association (BASMAA) recommended BMPs for extended detention ponds. The volume required for an on-line detention basin such as this one is not necessarily the same as the difference in total flood volume. The AFC Supplement states the detention basin would drain in 24 hours but does not give the design discharge from the detention basin nor is the pre-development peak discharge rate given. The detention basin would include a spillway in case of overflow, but the location and design of this spillway is not given. Based on Figure 8.14-4R, it appears the detention basin would be contained by an earthen embankment. Overflow of the earthen embankment, unless protection is provided in an armored spillway, could result in sudden failure of the embankment and release of all detained waters at once. DATA REQUEST
Response: Calculation sheets are provided as Attachment W&SR-133.
Response: This question will be responded to on January 18, 2002.
Response: The 10-year, 24-hour design basis has been accepted as the appropriate design standard in previous AFCs for power plants of similar size.
Response: As stated in our letter filed December 20, 2001, SMUD objects to this Data Request as being premature. The level of detail requested will be developed during the detailed design phase of the project. Final design will address the issues raised to ensure the overflow discharge does not contribute creek erosion.
Response: The stormwater discharge criteria are set by the State Water Resources Control Board (SWRCB). As a general guide, they look for turbidity, sediment and other visual signs that one or more Best Management Practices (BMPs) have failed, and require that any materials that might cause water quality degradation not be allowed to contact stormwater through containment or cover. A recent amendment to the Stormwater Regulations requires that: . . . should visual monitoring indicate that there has been a breach, malfunction, leakage, or spill from a BMP which could result in the discharge in storm water of pollutants that would not be visually detectable, or if storm water comes into contact with soil amendments or other exposed materials or contamination and is allowed to be discharged,. . . permittees [are required] to implement specific sampling and analytical procedures to determine whether Best Management Practices (BMPs) implemented on a construction site are: (1) preventing further impairment by sediment in storm waters discharged directly into waters listed as impaired for sediment or silt, and (2 ) preventing other pollutants, that are known or should be known by permittees to occur on construction sites and that are not visually detectable in storm water discharges, from causing or contributing to exceedances of water quality objectives. Discharges that flow through tributaries that are not listed in Attachment 3 [impaired water bodies] . . . are not subject to these sampling and analysis requirements. Examples of construction sites that may require sampling and analysis include: sites that are known to have contaminants spilled or spread on the ground; sites where construction practices include the application of soil amendments, such as gypsum, which can increase the pH of the runoff; or sites having uncovered stockpiles of material exposed to storm water. Visual observations before, during, and after storm events may trigger the requirement to collect samples.(Construction Activities General Storm Water Permit, SWRCB Order No. 99-08-DWQ) Stormwater discharges and industrial discharges are monitored by different sections of the RWQCB, applying standards which they consider appropriate. Generally the industrial discharge standards, are numerically more stringent. SWRCB standards require visual monitoring of stormwater, and this would be appropriate to the detention pond. Oil/water separator effluent is generally observed visually on a periodic basis. In the event stormwater fails to meet the required criteria, the RWQCB has the power to levee fines and issue enforcement actions against the discharger. It is the intent of SMUD to avoid any enforcement actions.
Response: As stated in our letter filed December 20, 2001, SMUD objects to this Data Request as being premature. The existing contours and final grading plan are shown on Figure 8.14-4. This figure also shows the location and routing of the stormwater collection system as well as drainage features. Exact location of laydown areas and other details will be developed during the detailed engineering design phase in the 3rd quarter of 2002.
Response: Storm water from outside equipment containment areas would be collected in a catch basin leading to an underground multi-chambered oil/sediment separator vault which allows the settling of sediments and the trapping of oil and grease prior to the discharge of stormwater into the detention basin. These collection chambers allow for regular inspection of the trapped sediment and oil/grease. Collected sediment and oil would be removed periodically from the chambers and properly disposed of by the means appropriate for sediment and oil/grease wastes. This is considered to be a Best Management Practice solution for the application. Debris would be removed using trash racks on the upstream side of the treatment system. By design, the detention basin is dry between storm events and therefore any sediment which did accumulate in the basin could be removed during the dry periods thus eliminating the risk of an effluent violation. Disposition (disposal to sanitary landfill or other site as required) of the collected sediments would be a function of the sediment composition. Periodic sampling of the basin soil would be a normal maintenance operation.
Response: From a design and engineering standpoint, the quantity and quality of stormwater runoff would be highly unreliable. The CPP treatment system would be designed to treat constituents as they are known to occur in FSC. Stormwater can occur suddenly and can have elevated amounts of turbidity, dissolved salts or other constituents that are not technically harmful, but for which special measures might need to be used in adapting the treatment system. For purposes of the power plant this would cause a substantial drop in reliability and increase in risk. The quantity being relatively small, the benefits of diverting this water would be offset by the additional costs and effort in design, treatment and monitoring that might be necessary. CPP is not planning to use stormwater in the cooling tower. Background The AFC commits to using secondary containment and curbing for all chemical storage areas. Data Request
Response: For the bulk chemicals the truck unloading area will be curbed and the area sloped to a drain. This drain will go to the secondary containment basin for the storage tank and will accommodate over 150 percent of the truck volume, plus the volume associated with the 25-year, 24-hour storm event. For tote chemicals, the unloading area will be curbed and drain to a catch basin sized to accommodate 150 percent of the largest tote volume plus the rain from the 25-year, 24-hour storm event. In the event of a spill, a qualified disposal company will pump the basin out. Rainwater accumulation will be periodically pumped out and delivered to the equipment drain system.
Response: Sufficient spill volume for the largest bulk delivery truck and storage will be accomplished by use of a secondary containment for the storage tank sized to contain 150 percent of the storage tank volume, plus the rainfall from a 25-year, 24-hour storm. BACKGROUND The AFC demonstrates through FEMA Federal Insurance Rate Maps that the CPP is not within the 100-year floodplain of Hadselville Creek (AFC Section 8.14.3.3). However, the absence of a FEMA-mapped floodplain does not necessarily mean a site is not subject to flooding. The CPP is adjacent to Clay Creek, which apparently has not been mapped by FEMA, and therefore has a 100-year floodplain of unknown extent. Several tributaries to Clay Creek cross the CPP site and the extent of flooding is also unknown. The AFC states and Figure 8.14-4R shows that several of these drainageways will be diverted around the CPP site but discharges and floodplains are not shown. Figure 8.14-4R shows a corner of the proposed detention basin very close to the creek bank where it could be subject to erosion from creek overbank flows. DATA REQUEST
Response: As stated in our letter filed December 20, 2001, SMUD objects to this Data Request as being irrelevant.
Response: As stated in our letter filed December 20, 2001, SMUD objects to this Data Request as being irrelevant.
Response: As stated in our letter filed December 20, 2001, SMUD objects to this Data Request as being irrelevant.
Response: As stated in our letter filed December 20, 2001, SMUD objects to this Data Request as being irrelevant. BACKGROUND Section 8.14.5.1 of the AFC describes impacts to three tributaries to Clay Creek and states that these drainageways are probably jurisdictional under Section 404 of the Clean Water Act. The AFC states that a 404 Permit will be required (as well as 401 Water Quality Certification) and that an environmental assessment will be performed and mitigation measures developed as a condition of obtaining these permits. The AFC describes how the proposed gas pipeline will cross a number of streams which are probably jurisdictional. DATA REQUEST
Response: SMUD has provided initial consultation letters and held telephone communications with each of these agencies. SMUD has requested that a “pre-consultation” meeting be held with these agencies and anticipates this will occur in mid-February, followed by submission of the 404, 401 and 1601 applications thereafter. BACKGROUND According to the AFC (page 8.14-17) the proposed gas pipeline will cross 27 rivers, creeks, irrigation canals, riparian areas, vernal pools, and other drainages that are potentially jurisdictianal wetlands including the Cosumnes River which, according to the AFC, can reach up to 35,000 cfs during storm events. During floods, river bed and bank scour could reach the depth of the pipeline and cause a rupture. One way to minimize the risk of this type of rupture is to bury the pipeline below the expected bed scour depth for a distance beyond the stream banks sufficient to avoid expected lateral erosion. The burial depth would affect trench width, which would affect riparian impacts. DATA REQUEST
Response: As stated in our letter filed December 20, 2001, SMUD objects to this Data Request as having no legal basis and is overly burdensome. BACKGROUND No mass & heat balances were provided in the AFC, thus it is uncertain whether the applicant proposes to use supplemental duct firing, which increases water consumption. DATA REQUESTS
Response: The ASHRAE 1% summer high for Sacramento AP is 100 F DB (dry bulb) and 72 F WB (wet bulb). A heat balance at that condition is presented as Figure W&SR-150. .The average water balance is shown in Figures 2.2-6a and b of the AFC. The monthly water requirements are shown in Table 7.1-1 (AFC page 7-2). AFC Figures 8.14-3c and d show the water balance at a peak condition of 104 F. No supplemental firing is being considered for the project. BACKGROUND Page 27 of the CPP Data Adequacy Response states that SMUD has a contract for 75,000 AFY of USBR water from the Folsom South Canal. During operation, the Rancho Seco Plant used approximately 28,000 AFY. Since closure, the plant has used approximately 15,000 AFY; and as with all USBR customers, water that is not used by SMUD is made available for other Central Valley Project (CVP) uses. Currently, the CVP dedicates 800,000 AFY year to fish and wildlife and 410,000 AF to State and wildlife refuges and wetlands pursuant to the Central Valley Project Improvement Act (CVPIA). Per CVP policy, SMUD’s unused RSP water has been made available for other CVP uses. With the proposed CPP using approximately 8,000 AFY with peak annual demands as high as 9,000 AFY, it is possible that this renewed use of American River water will decrease water currently used to meet Delta water quality standards or other fish and wildlife uses. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||