[California Energy Commission Letterhead]




September 2, 1998


Mr. Curt Hildebrand
Calpine
50 West San Fernando Street
San Jose, CA 95113

Ms. Charlene Wardlow
Calpine
1160 N. Dutton, Suite 200
Santa Rosa, CA 95401

Dear Mr. Hildebrand and Ms. Wardlow:

DISCUSSION OF POTENTIAL SIGNIFICANT ENVIRONMENTAL IMPACTS--WATER RELATED ISSUES; AND SUGGESTIONS REGARDING THE TRANSMISSION LINE ROUTE AND POINT OF INTERCONNECTION

At the last workshop we discussed providing Calpine with additional assumptions for remodeling water quality and temperature impacts. Upon further consideration, we believe spending additional time and effort modeling the discharges from the plant will not significantly change the result of exceedances of standards during certain months of the year and could potentially cause further delay in the schedule. Instead of providing remodeling assumptions, we are writing to outline our concerns and provide you with an opportunity to explain how you plan to address these potential significant environmental impacts discussed below. We will consider your response prior to the filing the Final Staff Assessment (FSA)/Draft Environmental Impact Statement (DEIS).

Water Quality

As you know, we conducted two public workshops to discuss the water quality and temperature modeling prepared by Foster-Wheeler. Although we agreed at the last workshop to provide numbers/assumptions we believed to be more appropriate than those used in the modeling, we now believe this would not be productive. There are several reasons: first, even if we accept the numbers and assumptions contained in the modeling, the results indicate that the aquatic life standard for arsenic and copper are exceeded in segments of the field drains. Staff's position is that the aquatic life water quality criteria is applicable to the field drains to ensure protection of the endangered Giant Garter Snake and its prey base.

Secondly, we do not agree with some of the more critical numbers and assumptions used in the modeling. Based upon information submitted in several data responses, it is clear that the most conservative values for several of the constituents were not used in the modeling. Data response No. 68 provided estimated flows and constituents for various wastewater streams for the project under peak and average operating conditions. Data was provided for groundwater from both the SPP-1 and south wells. We believe that the highest values for the constituents of concern for the total wastewater stream should have been used in the modeling. For example, zinc was not modeled due to not being detected in groundwater samples from the SPP-1 well. Zinc was detected, however, in samples from the South Well at 0.06 mg/l. The peak combined waste stream value for zinc in data response No. 68 is 0.134 mg/l. Manganese was apparently modeled using 0.45 mg/l yet was detected in the south well at 0.65 mg/l. Data response No. 68 indicates a combined waste stream value for manganese of 0.647 mg/l. Copper was modeled at 0.03 mg/l, yet was detected in the South Well at 0.06 mg/l and data response No. 68 indicates that the combined peak wastewater stream for copper is 0.134 mg/l.

An even greater concern is that the flow values used in the modeling do not represent a reasonable worse case analysis. It appears that during part of the fall season, the only flow present within the field drains is wastewater from Greenleaf 1. The modeling, however, calibrated values based upon sampling taken on May 6th when flows in the drains were high due to storm water runoff and/or irrigation return water. For example, flows half way down the field drains were calculated at 13.7 cfs. Since the proposed project's wastewater discharge flow was calculated to be 2.6 cfs, a significant amount of dilution is occurring. All of the modeling results show a substantial reduction in values (concentrations) in the field drains. Although this may occur during much of the year, this does not reflect a reasonable worst case analysis. We believe that such a case should be based on flows in the fall when the field drains are likely to consist entirely of wastewater from the two Calpine power plants. In such a situation, it is clear that the aquatic life criteria for copper, arsenic and manganese would be exceeded. The effects of such flows within the North Drain, the Sutter Bypass and the Sacramento River for all the water quality constituents of concern as well as temperature need to be further evaluated not only for project specific impacts but for cumulative ones as well. Evaluation of additional water quality project specific and cumulative impacts may necessitate additional mitigation.

Based upon these factors, we believe wastewater discharges from the project may cause a significant adverse impact on the aquatic biota. Furthermore, the U.S. Fish and Wildlife Service recommends that the project not result in any temperature increase in the North Drain from the proposed project's wastewater discharge. Under the conditions modeled, temperatures would increase 3.1 degrees Fahrenheit in the North Drain. We support U.S. Fish and Wildlife Service's position on this matter.
Mitigation of these water quality and temperature impacts could be accomplished through pre- or post-treatment to ensure that the wastewater discharge will not violate the aquatic life standard for copper and arsenic and will not raise water temperatures in the North Drain.

Drainage

Sutter County, in a letter from George Carpenter to Paul Richins dated August 25, 1998, has indicated that the North Drain and Pumping Plant No. 2 cannot accommodate additional flows from the proposed project during a 10-year storm. In light of this, please identify mitigation measures that will allow the drain and the pumping station to accommodate the additional flows during a 100 year storm. Depending on the approach, additional issues will need to be addressed such as wetland impacts resulting from on-site retention or the Department of Water Resources willingness to provide additional pump capacity at the drain.

Another issue is the status of Calpine's evaluation of the field drains. Paul Russell of the Sutter Extension Irrigation District believes that the culverts where the field drains run beneath the district's laterals will need to be expanded to accommodate the Sutter Power Project's peak wastewater discharges and stormwater runoff. Furthermore, it appears that at least a portion of the field drains themselves will have to be enlarged to accommodate these flows. As you are aware, any enlargement of the drains and associated culverts raises biological issues which would need to be addressed. One potential method to mitigate these drainage and biological impacts would be to add a zero wastewater discharge unit to the facility.

In a related drainage matter, it is unclear whether Calpine has an easement for use of these drains. Please address whether Calpine has established access or owns easements to these field drains or at least the status of its efforts to do so.

Groundwater

Sutter County has indicated that they do not believe there is sufficient information to evaluate the project's effects on groundwater quality. We have retained the services of a hydrogeologist to aide us in evaluating potential impacts from groundwater pumping due to the project. We recognize that groundwater quality limits the cycles the water can be used within the power plant. Yet water treatment or zero discharge can substantially reduce, at a cost, the amount of water pumped. Water treatment or zero discharge would also make the facility a much more water efficient power plant.


Based on the information available, we believe that wastewater and drainage issues dictate that Calpine treat the wastewater prior to discharge as well as retain, probably on-site, all stormwater runoff and wastewater for certain periods. The Sutter County letter suggests zero discharge as one treatment option to address the drainage issue. Certainly such an approach would resolve drainage and wastewater quality concerns as well as substantially reduce groundwater pumping. It is important that Calpine inform us of how these issues will be addressed.

Electric Transmission Line Route

Due to the potential for visual impacts, impacts to agricultural operations and the extreme public concern over the transmission line route, Sutter County and Energy Commission staff are reviewing alternative transmission line routes and points of interconnection. We are looking at the O'Banion site (this site is identified in the Preliminary Staff Assessment as an alternative site for the project and is located south of O'Banion Road) as a possible site for the switchstation and point of interconnection with Western Area Power Administration's (Western) electric transmission system. I have also asked Morteza Sabet, Western, to review the site. This site may have some advantages over the site originally proposed in the Application for Certification (north of O'Banion Road) and the currently proposed point of interconnection at the end of Murray Road. We recommend that you reconsider the O'Bainion Road transmission line route and evaluate O'Bainion Road site as a possible point of interconnection with Western's system. Depending upon our review, we may indicate a preference for this route and point of interconnection in the FSA/DEIS as an alternative to the Murray Road interconnection. Site control is also a consideration and I understand that the owner may be willing to entertain an offer on the parcel.

Conclusion

In summary, we believe the project has the potential to cause significant environmental impacts if not adequately mitigated. Prior to completing the FSA/DEIS, we would like to know how you plan to mitigate these potentially significant environmental impacts. Please provide this information to us by September 16, 1998, so that it can be included in the FSA/DEIS. In the absence of a clear understanding of how you plan to address these potential significant impacts, we will propose conditions and mitigation measures to reduce the impacts to a level of insignificance in the FSA/DEIS.


I recognize that the request for comment on these issues by September 16, 1998, gives you only two weeks to respond. However, your timely response will help to finalize these issues with a minimum impact to the schedule. If you have any questions please call me at (916) 654-4074.

Sincerely,




_____//signed//_____
Paul Richins, Jr.
Project Manager


cc:

Sutter Power Project Proof of Service List
Morteza Sabet, Western Area Power Administration
Kelly Hornaday, USF&WS, Endangered Species Division
Mike Wolder, Sutter Wildlife Refuge
Julie Brown, Department of Fish and Game
Bob Orcutt, Department of Fish and Game
Dale Whitmore, Department of Fish and Game
Cristyl Escarda, Central Valley Regional Water Quality Control Board



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