f modeling

Description of the Alternatives

This appendix provides a more detailed description of the alternatives that were evaluated in the Framework process. All seven alternatives were analyzed using the Bonneville Power Administration’s (BPA) HYDSIM computer model. Alternatives 1, 4, and 6 were analyzed by the Northwest Power Planning Council (NWPPC) staff. Alternative 2 was analyzed by the Columbia River Intertribal Fish Commission (CRITFC). Alternatives 3, 5, and 7 were analyzed by the BPA.

These analyses should be considered preliminary and subject to change. In all cases, the general intent of each alternative was captured, however, in some cases not all aspects of the strategy could be modeled due to lack of data or time. This appendix describes the seven alternatives as they were modeled. Because of that, it should be noted that the descriptions below and in the summary in Table F-23 could differ from other descriptions or summaries of the Framework alternatives.

In the discussion below, the vision for each alternative is summarized, followed by a description of the required changes to the hydroelectric system’s operation in order to implement that vision. All actions taken are relative to the National Marine Fisheries Service’s (NMFS) 1998 biological opinion.

We begin with a description of Alternative 4 because this scenario is closest to current river operations under the 1998 biological opinion. The analysis for Alternative 4 is exactly the same as the 1998 biological opinion as modeled by BPA. This option calls for experimentation with flood control elevations, integrated rule curves, spill, and other potentially helpful operations. However, because these are all yet to be tested, none was modeled in the analysis for this alternative.

Alternative 4: Conduct Managed Experiments Before Making Major System Changes

In this alternative, 10 to 12 years of carefully designed experiments will be conducted to assess the effectiveness of various approaches to recovery of Columbia River fish and wildlife. These ambitious experiments are obviously also expected to help the listed species. Findings will be evaluated before further capital improvements or decisions on major dam reconfiguration are made.

General Modeling Assumptions

The modeling assumptions for this alternative reflect the intent of the NMFS’ 1998 biological opinion. All project non-power requirements are derived from the Pacific Northwest Coordination Agreement (PNCA) plant data book, specifically from the 1997 operating year planning process.

The 50 years of historic stream flows used in this analysis come from the document entitled "Modified Streamflows 1990 Level of Irrigation," dated July 1993. They contain the 1990 level of irrigation depletion. Slight adjustments to these 1990-level modified stream flows were made by the U.S. Bureau of Reclamation to update Grand Coulee’s pumping schedule for the Columbia Basin Project.

Flood control curves (Upper Rule Curves or URCs) were calculated by using forecasted volume runoff based on the Kuehl Moffitt Report dated July 1986. The data incorporate a shift of system flood control from Dworshak and Brownlee (when the April-through-July runoff volume forecasts are less than 3.2 million acre-feet (MAF) and 5.8 MAF, respectively) to Grand Coulee and incorporate the 2.08 MAF Mica and 5.1 MAF Arrow flood control allocation. Flood control will take precedence over all non-power requirements, except the International Joint Commission (IJC) 1938 Order at Kootenay Lake.

Plant Specific Modeling Assumptions

Mica, Duncan, and Arrow

reservoirs are operated according to the Detailed Operating Plan (DOP) developed jointly by the Entities as defined in the Canadian Treaty.

Additionally, Arrow will store up to 1 MAF of water in years when the January-through-July runoff volume forecast (95 percent confidence level) at The Dalles is less than 90 MAF. This additional water will be released April 16 through June 30, as needed, to meet the McNary flow augmentation targets. If conditions change by April 1 so that flow augmentation water is no longer needed, any amount already in storage at Arrow will be released by April 15.

Non-treaty water stored at the Mica Reservoir is not used in this analysis.

Libby

 is operated to meet power needs from September through December, subject to monthly minimum draft limits computed to achieve its December flood control elevation (2411.0 feet or 1502.2 Ksfd). From January through mid-April, outflow at Libby is reduced to its minimum requirement unless flood control would be violated. It should be noted that Libby can violate its flood control limit for the IJC operation at Kootenay Lake.

Libby

 is operated mid-April through July for protection of white sturgeon in all water conditions by releasing water to help maintain minimum flow requirements at Bonners Ferry. The minimum flow requirement at Bonners Ferry is 15,000 cubic feet per second from May 1 through May 9. From May 10 through June 20, Libby’s outflow reflects a full turbine operation. From June 21 through July 11, Bonners Ferry minimum flow requirement is 11,000 cubic feet per second. Table F-1 shows the computed Libby minimum outflow requirement for white sturgeon protection. Libby’s maximum outflow from mid-April through August is 25,000 cubic feet per second, which is the assumed full turbine operation without spill.

In August, Libby can be drafted as low as 20 feet from full (2439.0 feet or 2061.3 Ksfd) to contribute to flow augmentation at McNary Dam.

Kootenay Lake

 will be operated as necessary, up to free flow, to maintain the lake level below the IJC rule curve and the calculated "allowable elevation at Queens Bay." This is implemented using the five-step method as developed by BPA and the U.S. Army Corps of Engineers (COE). After August 31, the lake level may be raised to elevation 1745.32 feet at the Queens Bay gage. This maximum elevation at Queens Bay is in effect through January 7. After January 7 the lake will be lowered to at least 1,744 feet by February 1, 1,742.4 feet by March 1, and 1,739.32 feet by April 1. From April 1^st through August 31, if the lake elevation exceeds 1739.32 feet at the Queens Bay gage, the lake will be operated using the "allowable elevation" calculation until the elevation at the Nelson gage gets back to 1,743.32 feet.

Hungry Horse

 is operated to meet power needs from September through December, subject to monthly draft limits of 3,531 feet (1215.7 Ksfd) in September, 3,526 feet (1162.0 Ksfd) in October, 3,521 feet ( 1108.3 Ksfd) in November, and 3,515.0 feet (1049.0 Ksfd) in December. From January through March, outflow at Hungry Horse is reduced to its minimum requirement unless flood control would be violated. From April through July, Hungry Horse operates at or near flood control elevations.

In August, water from Hungry Horse is used for flow augmentation at McNary, subject to drafting limits of 3,550 feet (1427.7 Ksfd) by August 15 and 3,540 feet (1312.3 Ksfd) by August 31. Hungry Horse is operated to support the Columbia Falls minimum flow requirement of 3,500 cubic feet per second and Columbia Falls’ maximum flow limit of 4,500 cubic feet per second from October 15 through December 15. Hungry Horse’s maximum outflow from mid-April through August is set to its powerhouse hydraulic capacity plus 3,000 cubic feet per second spill.

Albeni Falls

 is operated in September to 2,060.0 feet (465.7 Ksfd). In October through April, Albeni Falls is operated to 2,055.0 feet (279.0 Ksfd). In May, Albeni Falls is operated to 2,057.0 feet (325.7 Ksfd). From June through August, Albeni Falls is operated to full pool elevation or 2,062.5 feet (582.4 Ksfd).

Grand Coulee

 is operated to meet power needs from September through December, subject to draft limits of 1,280 feet in September and October, 1,275 feet in November and 1,265 feet in December. From January through mid-April, Grand Coulee is operated to a set of minimum elevation limits that are designed to get the reservoir to its flood control elevation by April 15 with the desired probability. During this time period, Grand Coulee also provides water releases to maintain the required minimum flow at Priest Rapids for the Vernita Bar operation (described below). From mid-April through June, Grand Coulee may be drafted to the lower of flood control or 1,280 feet to support McNary flow augmentation targets. In July and August, Grand Coulee may be drafted as low as 1,280 feet (2216.4 Ksfd) to support McNary flow augmentation targets. At-site minimum flow is 30,000 cubic feet per second. Grand Coulee is subject to a daily drawdown limit of 1.3 feet per day.

Vernita Bar

 minimum flows (measured at Priest Rapids Dam) for December through May vary by water condition, with minimum flows established as the lesser of 68 percent of the Wanapum’s October or November flows or 70,000 cubic feet per second. Values less than 70,000 cubic feet per second are rounded to the nearest 5,000 cubic feet per second. This minimum flow is controlled by releases from Grand Coulee Reservoir.

Upper Snake

 River dams are operated in a manner to attempt to provide 427,000 acre-feet of water for spring and summer flow augmentation each year. Since these dams are not modeled explicitly, the effect of their operation is incorporated into Brownlee Dam’s inflow data. The full 427,000 acre-feet of additional water from these projects is not always available.

Brownlee

 will be operated to the fixed operation submitted for PNCA planning. In September, Brownlee is drafted an additional 100,000 acre-feet for flow augmentation. From October through December, Brownlee attempts to maintain an outflow as close to 9,000 cubic feet per second as possible. In October a draft limit of 2,051.0 feet (325.7 Ksfd) is imposed during dry years and a limit of 2034.6 feet (240.1 Ksfd) is imposed during median to high water years. From January through April, Brownlee’s outflow reduced to fill the reservoir. In May, Brownlee is drafted to or maintained at 2,069 feet (436.4 Ksfd). The reservoir is maintained at 2,069 feet in June. In July, Brownlee is drafted down to 2,067.0 feet (423.1 Ksfd). This elevation is held in July and August.

Dworshak’s

outflow is reduced to its minimum requirement of 1,300 cubic feet per second from September to March in order to store as much water as possible for the salmon migration period. From April through August Dworshak is drafted to meet Lower Granite flow augmentation targets. Dworshak may only be drafted to 1,520 feet by August 31. During the migration period, Dworshak’s outflow is limited to 14,000 cubic feet per second and is limited to 25,000 cubic feet per second in all other periods for downstream flood control.

Generation at the four Lower Snake and four Lower Columbia dams (Lower Granite, Little Goose, Lower Monumental, Ice Harbor, McNary, John Day, The Dalles, and Bonneville) is further reduced with the inclusion of juvenile bypass fish spill requirements, as reflected in the 1998 biological opinion. If the regulated outflow at Lower Granite is less than 100,000 cubic feet per second then there is no spill at the project; otherwise, spill will be 80 percent of instantaneous flow at Lower Granite. If the regulated outflow at Lower Granite is less than 85,000 cubic feet per second then there is no spill at Little Goose and Lower Monumental; otherwise, spill will be 80 and 81 percent of instantaneous flow at Little Goose and Lower Monumental, respectively. Bonneville has a daytime spill cap of 75,000 cubic feet per second from 0600 to 1800 hours. Juvenile bypass fish spill at federal projects (percent of outflow), limited by spill caps, isas shown in Table F-2.

Juvenile bypass spill requirements at non-federal projects are described below in Table F-3. Spill requirements at Rock Island Dam are provided in Table F-4.

The 1998 biological opinion calls for flow objectives at McNary Dam from April 20 through August. From April 20 through June, the flow target ranges from 220,000 to 260,000 cubic feet per second based on the forecasted January-through-July runoff volume at The Dalles. In years when the runoff volume is predicted to be less than 85 MAF, the flow target is set to 220,000 cubic feet per second. In years when the runoff volume is expected to be higher than 105 MAF, the target is 260,000 cubic feet per second. For years in between, a linear interpolation between the low and high target values is used. For July and August, the flow target is set to 200,000 cubic feet per second. The sequence for releasing water from upstream reservoirs for flow augmentation is to draft Grand Coulee first followed by Libby and then Hungry Horse.

The1998 biological opinion flow objectives for Lower Granite Dam range from 85,000 to 100,000 cubic feet per second from April 1 through June. When the forecasted April-through-July runoff volume at Lower Granite is less than 16 MAF, the target is set to 85,000 cubic feet per second. When the forecasted runoff volume is expected to be higher than 20 MAF, the target is 100,000 cubic feet per second. For years in between, a linear interpolation is used. For July and August, the flow objective ranges from 50,000 to 55,000 cubic feet per second again depending on the same forecasted runoff volume at Lower Granite.

John Day

 is operated at an elevation of 262.5 feet from mid-April through September. From October through mid-April, John Day is operated to an elevation of 265 feet.

Lower Snake River dams (Lower Granite, Little Goose, Lower Monumental and Ice Harbor) are operated within one foot of their minimum operating pool (MOP) elevations from approximately April 10 through August 31. Lower Granite will continue to operate within one foot of MOP through November 15. Minimum operating pool elevations are; 733 feet at Lower Granite, 633 feet at Little Goose, 537 feet at Lower Monumental, and 437 feet at Ice Harbor. During the rest of the year Lower Granite, Little Goose, Lower Monumental, and Ice Harbor will operate at normal pool elevations or 738, 638, 540 and 440 feet, respectively.

Alternative 1: A Connected Self-Sustaining Ecosystem

This alternative describes an ecosystem that has an increased ability to be self sustaining in a state consistent with the biological needs of native fish and wildlife. The system would provide increased levels of ecological services, intrinsic benefits as well as significant conventional economic services. The system would support diverse, naturally spawning fish and wildlife that transcend current blockages. Fish and wildlife spawn and function naturally. Human services such as power generation and transportation are mostly eliminated in the Lower Snake and reduced in the Columbia River.

Modeling Assumptions

To achieve river flows that mimic the natural hydrograph, all reservoirs are held as full as possible (i.e., to flood control elevations) in all months except August. This strategy essentially allows the dams to pass inflows while maintaining high reservoir elevations for resident fish, recreation, irrigation, etc. In high runoff years (i.e., wet years) reservoirs would be drafted in late winter or early spring to make space for the anticipated runoff and protect against flooding.

In this alternative the 1998 biological opinion flow objectives in the Snake and Columbia rivers are removed. In their place, flow targets of 135,000 and 105,000 cubic feet per second are added at The Dalles Dam for the first and second half of August, respectively. Also, flow targets of 30,000 and 20,000 cubic feet per second are added at Lower Granite Dam for the same time period. These flow objectives help raise river flows above the natural hydrograph in August for both temperature control and for increased river velocity.

Flood control limits (i.e., ceiling elevations) are modified at Libby, Hungry Horse and Grand Coulee dams using a variable-flow methodology (VARQ) developed by the COE. This change provides more space to store water in the early spring months while not increasing the risk of flooding downstream. In general, the flood control elevations at Libby and Hungry Horse dams are raised and the limits at Grand Coulee Dam are lowered somewhat.

Year-round minimum-elevation limits have been developed for Libby and Hungry Horse reservoirs to protect resident fish populations. These limits are often referred to as biological rule curves. This alternative calls for the implementation of these rule curves. Unfortunately, these curves occasionally conflict with the flood control operation. In order to eliminate this conflict, the biological rule curves have been integrated with the variable-flow flood control limits to create what are known as the "integrated rule curves." These integrated rule curves are included in this alternative but because the system is operated to flood control elevations nearly year round, this action is unnecessary. Similar integrated rule curves for Grand Coulee and Dworshak reservoirs are yet to be fully developed.

Libby, Hungry Horse, Grand Coulee, and Dworshak reservoirs are drafted in August, if necessary, to achieve the flow objectives at The Dalles and at Lower Granite as defined above. Libby is drafted no lower than 2,455 feet (the 1998 biological opinion limit is 2,440 feet). Hungry Horse is not drafted below 3,555 feet (the 1998 biological opinion limit is 3,540 feet). Grand Coulee is not drafted below 1,287 feet (the 1998 biological opinion limit is 1,280 feet) and Dworshak is not drafted lower than 1,590 feet (the 1998 biological opinion limit is 1,520 feet).

Of the 12 MAF of storage in the Mica Reservoir in Canada, 7 MAF are a part of the Canadian Treaty with the United States. That storage along with storage in other Canadian and U.S. reservoirs is called "treaty" storage. The total treaty storage in the system is managed to provide the most efficient use of that water, limited to whatever non-power constraints are in effect. The remaining 5 MAF of storage in Mica is referred to as "non-treaty" storage and is used to supplement the use of treaty water. The U.S. and Canada equally share the benefits of the non-treaty water. In this alternative, 1 MAF of non-treaty water stored in the Mica Reservoir is used for flow augmentation in August.

The four Lower Snake River dams (Lower Granite, Lower Monumental, Little Goose, and Ice Harbor) and John Day and McNary dams are "breached" in this alternative. In this case the word "breached" means that, to the extent possible, the dams are kept in place while the river is routed around them. According to the COE, this is the least costly method of providing natural flows. At the same time, this allows the existing generators at the dams to be converted to synchronous condensers, if necessary, to support transmission stability.

Spill requirements are not necessary at dams that have been breached. For other dams, this alternative includes the same spill provisions as in the 1998 biological opinion.

Alternative 2: A Reconnected Ecosystem To Support Salmon Harvest

This alternative describes an ecosystem that has an increased ability to sustain a condition that supports harvestable salmonid populations with decreased amounts of external support. Other biological elements (e.g., resident fish and wildlife) would develop within communities consistent with this primary goal. The system would provide increased levels of harvest, ecological services, and intrinsic benefits as well as significant conventional economic services.

A primary goal is to restore diverse and harvestable salmon stocks. In this alternative, the Columbia Basin is a largely naturally-functioning, self-sustaining ecosystem aimed at increasing and sustaining salmon harvest. Areas above and below the dams are treated as separate systems. Power generation and navigation are reduced in the Columbia River and drastically reduced in the Lower Snake River.

Modeling Assumptions

Water in federal reservoirs along with some Canadian and Upper Snake Basin water is used to attempt to achieve the flow objectives at The Dalles and at Lower Granite dams listed in Table F-5. The current flow objectives (under the 1998 biological opinion) at Priest Rapids Dam are not changed in this alternative.

The four Lower Snake River dams (Lower Granite, Lower Monumental, Little Goose, and Ice Harbor) along with the John Day Dam are breached.

One MAF of non-treaty water stored in the Mica Reservoir is used along with an additional 900,000 acre-feet of water from the Arrow Reservoir to aid in achieving the flow objectives in Table F-5.

One MAF of water diverted from Banks Lake are used to help achieve the flow objectives in the Columbia River.

An additional 500,000 acre-feet of water from the Brownlee Reservoir is used to aid in flow augmentation from July through September in the Snake River. This is in addition to the volume provided under the 1998 biological opinion.

An additional 1 MAF of water from the Upper Snake River Basin is to be acquired, whenever possible, to aid in achieving the flow objectives. (This water is in addition to the 427,000 acre-feet provided in the 1998 biological opinion).

During winter months, the outflow at federal dams is reduced to minimum levels to fill the reservoirs as much as possible for the upcoming migration season. Flood control elevations are not violated.

Variable-flow flood control limits are implemented at Libby, Hungry Horse, and Grand Coulee dams. This allows more space in the Libby and Hungry Horse reservoirs to store water for flow augmentation. In addition, flood control space is further reduced at Grand Coulee by a maximum of an additional 1.8 MAF and at Dworshak by a maximum of 600,000 acre-feet and at Brownlee by a maximum of 200,000 acre-feet. This reduction in flood control space will increase the risk of flooding downstream. No assessment was made as to the magnitude or cost of the increased risk.

Integrated rule curves are not used in this alternative.

During the migration period between April and June, Dworshak Reservoir is not drafted below 1,495 feet for flow augmentation. In July, August, and September, Dworshak’s minimum draft elevation is 1,520, 1,535, and 1,520 feet, respectively.

Grand Coulee is not drafted below 1,277.6 feet (2150 KSFD) in August for flow augmentation.

End-of-August draft limits at Libby and Hungry Horse dams are the same as under the 1998 biological opinion.

Alternative 3: A Strong Snake River Ecologically Connected to the Columbia River To Aid Harvest

An ecosystem that is maintained in a state that facilitates existing salmon harvest patterns and provides increased harvest opportunities. The system would provide increased levels of harvest, ecological services, and intrinsic benefits as well as significant conventional economic services.

Under this alternative, Snake River fall chinook salmon numbers will be built up to eliminate the mixed-harvest conflict with the more robust populations of Hanford Reach fall chinook salmon. Other tributary areas supporting other species are ecologically healthy. Transportation and generation in the Lower Snake are eliminated.

Modeling Assumptions

In this alternative, the water budget flow objectives at McNary Dam established in the 1998 biological opinion are implemented in every year. (In the 1998 biological opinion, the flow objectives in dry years are waived.)

All water budget flow objectives for the Snake River are removed.

The four Lower Snake River dams (Lower Granite, Lower Monumental, Little Goose, and Ice Harbor) along with the John Day Dam are breached.

Integrated rule curve limitations are observed at Libby and Hungry Horse dams.

As in the 1998 biological opinion operation, water from the Libby Reservoir is used to augment flows for sturgeon in May, June, and July. However, in this alternative, priority is given to the integrated rule curve operation in those months. Thus, flows for sturgeon are augmented only if Libby’s elevation does not drop below the integrated rule curve level.

Up to 3 to 5 MAF of non-treaty water from the Mica Reservoir are used, whenever available for flow augmentation in the Columbia River.

Unlike the 1998 biological opinion operation, that attempts to refill federal reservoirs in June to provide more water for August flow augmentation, this alternative gives the June flow objectives a higher priority. The hope was that with the additional non-treaty water from Mica, July and August flows would not be greatly reduced.

Spring and summer flow targets are based on the 1998 biological opinion standard, except at Lower Granite Dam.

Use water from the Grand Coulee reservoir (within limits) and from non-treaty storage to maintain a minimum flow at Bonneville Dam of 125,000 cubic feet per second from November through April for Chum salmon. Drafting limits at Grand Coulee for this operation are set at 1,269.3 feet in November and 1,264.3 feet in December.

The same spill is provided as in the 1998 biological opinion.

The variable-flow flood control elevations at Libby, Hungry Horse, and Grand Coulee reservoirs are used in this alternative.

Dworshak is not used for flow augmentation at McNary Dam.

Alternative 5: Rebuild Fish and Wildlife Without Major System Reconfiguration

Build healthy and harvestable salmon and resident fish populations and stabilize weak stocks while preserving current benefits of multipurpose dams. Mitigate for loss of wildlife habitat while respecting private property rights.

Modeling Assumptions

The 1998 biological flow objectives at Lower Granite and McNary dams are implemented in this alternative.

Use up to 3 to 5 MAF of Mica non-treaty storage for flow augmentation in the Columbia River.

No operation for chum salmon is included in this alternative.

The integrated rule curve limitations are not implemented in this alternative.

Unlike the biological opinion operation, that attempts to refill federal reservoirs in June to provide more water for August flow augmentation, this alternative gives the June flow objectives a higher priority. The hope was that with the additional non-treaty water from Mica, July and August flows would not be greatly reduced.

Bypass spill for fish passage is increased to the levels indicated in Table F-6.

No dams are breached in this alternative.

The variable-flow flood control elevation limits at Libby, Hungry Horse, and Grand Coulee reservoirs are used in this alternative.

Alternative 6: Rebuild Species By Making Limited Adjustments In Current River Operations

Build healthy, harvestable salmon and resident fish populations and stabilize weak stocks at acceptable cost while maintaining existing types and levels of economic and social benefits. Mitigate for loss of wildlife habitat while respecting private property rights.

This alternative would allow for making limited adjustments in river operations for fish, increasing investment in habitat and other measures, and reducing mixed-stock harvest. Like Alternative 5, this alternative aims to build a healthy, harvestable salmon populations and stabilize weak stocks at an acceptable cost.

Modeling Assumptions

This alternative keeps most of the operations in the 1998 biological opinion.

All spring flow objectives for the Snake and Columbia rivers are removed.

Variable-flow flood control elevation limits are implemented at Libby, Hungry Horse, and Grand Coulee dams.

Integrated rule curve drafting limits are imposed at Libby Dam year round.

Integrated rule curve drafting limits are imposed at Hungry Horse Dam from January through August (no IRC operation is applied from September through December to minimize water forced out in spring due to flood control).

Bypass spill requirements are removed at the collector dams (Lower Granite, Little Goose, Lower Monumental, and McNary).

The Brownlee Reservoir contributes 500,000 acre-feet of water in late summer for flow augmentation.

Dworshak is kept as full as possible through July. In August, 1 MAF of water is used for flow augmentation.

Draft limits at federal reservoirs in spring and summer months for flow augmentation are the same as in the 1998 biological opinion.

The 1998 biological opinion requirement to fill Libby, Hungry Horse, and Grand Coulee reservoirs during the winter months is removed.

Alternative 7: Rebuild species while maintaining all current river uses

Develop the Columbia River Basin primarily to maintain and enhance existing types of economic returns and services. Institute fish and wildlife mitigation that provides positive economic return to harvest and other social benefits.

This alternative would make major adjustments in current river operations to finance habitat and other measures, and would eliminate mixed-stock harvest. Like Alternatives 5 and 6, this alternative aims to build a healthy, harvestable salmon populations and stabilize weak stocks at an acceptable cost.

Modeling Assumptions

The modeling assumptions for this alternative are based on a pre-water budget operation (circa 1980). The system is optimized for power production while maintaining flood control and other miscellaneous non-power constraints. All fish and wildlife constraints (as described in Alternative 4 under the 1998 biological opinion) have been removed. This alternative provides no bypass spill at any project.

Besides not imposing any fish and wildlife constraints on the system, the rule curves developed for this alternative were optimized to maximize power production.

Summary of Results

While the amount of data produced by the HYDSIM program can be voluminous, the tables in this section include only the data (with one exception) that were forwarded to the Human Effects and Ecological work groups. Those data summarizes the monthly changes in hydroelectric generation and in river flows. To be a little more complete, a summary of monthly changes to reservoir elevations is also included. Other study results can be summarized fairly easily if the need arises.

Data to the Human Effects Group (Hydroelectric Generation)

These data include the 50-year average monthly hydro generation for each alternative. This generation does not include generation from hydro-independent dams and does not take into account the generation required for pumping at Grand Coulee Dam. Table F-7 provides the average monthly generation for each alternative and Table F-8 provides the differences in monthly generation relative to Alternative 4.

Data to the Ecological Group (River Flows)

These data include the 50-year average monthly river flows at Priest Rapids, McNary, and Lower Granite dams in cubic feet per second. In addition, monthly river flows for a typical wet year (1969) and a typical dry year (1973) are included. Tables F-9 to F-11 summarize the average, wet, and dry year flows at Priest Rapids Dam. Tables F-12 to F-14 summarize the flows at The Dalles Dam. Tables F-15 to F-17 summarize the flows at Lower Granite Dam.

Other Pertinent Results (Reservoir Elevations)

In addition to the data above, the 50-year average monthly elevations at Libby, Hungry Horse, Grand Coulee, Dworshak, and Brownlee dams are included. These monthly average elevations are shown in Tables F-18 to F-22 in units of feet above sea level and are rounded to the nearest foot.