The average water demand for the project of 7,359 lpm (1,885 gpm) represents 2.8 percent of the Port of Umatilla's allocation of 4.4 cms (155 cfs) (263,346 lpm [69,569 gpm]). Although the Port of Umatilla is not yet withdrawing water from the Columbia under its existing water allocation, the quantity of water required for the proposed project (0.12 cms [4.2 cfs]) (7,359 lpm [1,944 gpm]) is minuscule compared to the 4,808 cms (169,800 cfs) (288,490,384 lpm [76,211,334 gpm]) flow in the Columbia River at McNary. The project would increase impervious surfaces at the proposed cogeneration facility, potentially increasing runoff from the site. To control increases in stormwater runoff from the cogeneration facility site, a stormwater management system has been designed. Stormwater runoff from these areas would be conveyed into a detention basin designed to handle the 100-year, 24-hour storm event. This could result in a very small decrease in groundwater recharge, but would have a minor effect on groundwater quantity.
Land application of the 553 lpm (146 gpm) project wastewater effluent would be managed during the non-growing season to prevent nitrogen build-up because of lack of plant uptake of nutrients, and runoff of effluent over frozen ground. During the period of intermittent freezing of soil surfaces (November 16 to March 15), process water effluent incorporated into the Simplot land application system would be temporarily stored in an existing 644-million l (170-million gallon) storage pond, capable of storing the combined process water for a maximum of 113 days. The pond would store process water during the late fall and winter for reuse during the growing season.
A recent study (Cascade Earth Sciences Ltd. 1994) has shown that there is "no significant negative effect associated with the discharge of cogeneration plant wastewaters to Simplot's process water agricultural recycle system or sanitary wastewater treatment system." Furthermore regarding groundwater, "process water discharged from the cogeneration plant to Simplot's process water agricultural recycle system will result in a decline of 1.2 percent in total salt concentrations and 14 percent in total nitrogen concentrations." Based on the study data, Oregon Department of Environmental Quality (ODEQ) has approved discharge of cogeneration plant wastewaters to Simplot's system, and no adverse impacts are anticipated.
The boiler and steam turbine system present special requirements for water quality and demand special protection from corrosion and oxidation. A phosphate-polymer system would be used to control corrosion, an oxygen scavenger would be used to remove dissolved oxygen, and a neutralizing amine as morpholine would be used to control condensate pH.
For biological control an oxidizing biocide, sodium hypochlorite (NaOCl) would be used. It is a widely used commodity chemical popular for its efficiency and reasonable cost.
Caustic soda or sodium hydroxide (NaOH) is used as a corrosion inhibitor in the recirculating cooling system.
DEAE or diethylaminoethanol is widely used as a corrosion inhibitor in boilers to protect piping and metal surfaces in steam distribution systems. In this application, it is referred to as a "neutralizing amine" since it neutralizes carbonic acid which corrodes metal surfaces in steam and condensate systems.
Nitrite, Molybdate, Tolyltriazole, and Polycrylate polymer would be used as corrosion inhibiters in the closed cooling water system that would not be part of the discharge.
Sodium metasilicate, sodium hydroxide, and sodium tetraborate be used as corrosion inhibitors in the cooling water system. These chemicals are diluted and are consumed in small quantities, at low rates and will be FDA approved because some of the steam would be used in the J.R. Simplot potato plant.
The cogeneration wastewater would be mixed with the effluent from the J.R. Simplot potato processing plant and applied to existing acreage now being used for wastewater land application.
The J.R. Simplot Company applied for an amendment of its current Water Pollution Control Facilities (WPCF) permit (No. 100518) to the Oregon Department of Environmental Quality, Water Quality Division on November 18, 1994 to allow incorporation of HPP cogeneration effluent.
ODEQ determined that HPP demonstrated through application of appropriate process controls, that the HPP cogeneration facility would be capable of generating process wastewater, which for select wastewater parameters, would be substantively equivalent in characteristics to potato process wastewater currently treated and disposed by Simplot under the WPCF permit.
ODEQ approved the amendment of J.R. Simplot's WPCF permit to allow land application of wastewater from HPP's cogeneration facility on November 30, 1994.
No additional treatment of wastewater would be required.
The project would store and use a number of chemicals that, if spilled or otherwise accidentally released, could potentially contaminate local and regional surface waters and underlying aquifers. Mitigation measures included in project design and recommended in this EIS would protect surface and groundwater from spill contamination, as further discussed in Section 4.11 (Public Health and Safety).
Water quality in the Umatilla River at the two Western 230-kV Alternative river crossings could be adversely affected by erosion and sedimentation during construction. Mitigation measures and design features are further discussed in Section 4.1 (Geology, Soils, and Floodplains).
The following measures will be implemented to mitigate potential impacts to water quantity and quality:
The proposed project would require an average water withdrawal of 0.12 cms (4.2 cfs) (7,135 lpm [1,885 gpm]) from the Columbia River, already accounted for in the Port of Umatilla's water rights allocation. The average flow of the Columbia River at McNary is approximately 5,600 cms (200,000 cfs) (339,800,216 lpm [89,766,000 gpm]). Therefore, this withdrawal would have a minor impact on the quantity of water remaining in the river to support other uses. Properly managed land application of the project's wastewater (as planned) will likewise have a minor impact on surface or groundwater quality. Therefore, impacts to water resources are considered low.
The proposed project water use would contribute incrementally to local and regional cumulative impacts associated with water withdrawals from the Columbia River. Locally, two other power generation facilities are under construction: (1) the Coyote Springs Cogeneration Project in Morrow County near the town of Boardman, and (2) the Hermiston Generating Project 4.8 km (3 miles) east of the proposed project.
The Coyote Springs project would consume approximately 0.16 cms (5.6 cfs) (9,513 lpm [2,513 gpm]), supplied by either: (1) Port of Morrow groundwater wells, which the Oregon Department of Water Resources has determined are hydrologically connected to Columbia River flows (Energy Facility Site Council [EFSC] 1994); or (2) water from the Columbia River through water rights secured by the Port of Morrow and the city of Boardman. The Port of Morrow is currently petitioning for additional groundwater rights.
The Hermiston Generating Project would consume approximately 0.11 cms (3.8 cfs) (6,458 lpm [1,706 gpm], supplied from the Port of Umatilla's Columbia River allocation.
Permitted water rights in the vicinity of the three projects are not currently being used to the maximum extent. Actual water usage will increase if these plants come on line, and impacts to regional water resources beyond current conditions may result.
The Port of Umatilla holds a water right for withdrawing 4.4 cms (155 cfs) (263,346 lpm [69,569 gpm]) from the Columbia River. The cumulative impacts to the Port of Umatilla's supply from the Hermiston Generating Project and the proposed project's use of 0.229 cms (8 cfs) (13,593 lpm [3,591 gpm]) would be about 5 percent of the Port's allocation. This would be a low cumulative impact on the Port's water supply.
The withdrawal of an average 0.12 cms (4.2 cfs) (7,135 lpm [1,885 gpm]) for the proposed cogeneration facility could result in the potential loss of electrical energy generation at four downstream Columbia River Federal power projects McNary, John Day, The Dalles, and Bonneville particularly in the low flow months of August through January when all flow would normally be routed through the turbines at one or more of the projects. On average, the withdrawal would reduce generation by about 756 megawatt hours (MWh) annually, or about 0.0023 percent of the annual 32.8 million MWh output of the four projects. The generation foregone due to the withdrawal would need to be replaced by BPA through increased generation at other projects or increased power purchases. The revenue loss of the foregone generation would be about $20,000 annually. The effects on BPA rates in absorbing this revenue loss would be real, but imperceptible to the consumer. Similar effects would be attributable to the Hermiston Generating Project and Coyote Springs projects, and other water withdrawals. Each would very slightly reduce the quantity of water remaining in the river to support other uses.