Under consideration is a CRSO comment proposal for a 30-mile canal/pipeline to be built upon the gently sloping abandoned Burlington Northern railgrade current shorelline of Ice Harbor reservoir, currently owned by Washingon State as an underused part of their Columbia Plateau State Park Trail system. This option would have no pumping costs as the water would be gravity fed to the same elevation that irrigators currently pump. The primary expense concerns the annual delivery of 100,000 acrefeet/year of irrigation water, requiring a great length of a large diameter pipe, installed cost estimated at $50 million. To moderate this need, an "optional feature" reservoir (see Annex O below) should be considered.
Water Supply - 3.4.1 Basic Assumptions -- Appendix I - FR/EIS (February 2002)
Irrigated farmland operators that currently pump water from the Ice Harbor reservoir will no longer be able to pump water from the reservoir under dam breaching conditions, and the value of the impacted 37,000 acres of farmland would be reduced to non-irrigated grazing land. This change in farmland value represents the economic effect of dam breaching on pump irrigators.
Response to Comments -- Appendix U - FR/EIS (February 2002)
Comment: Build a small (passable) dam near Lewiston to maintain water level/withdraw water at mothballed Lower Granite for irrigation.
Response: The irrigation demands in the vicinity of Lewiston are minimal. Provisions are included in Appendix D, Natural River Drawdown Engineering to deal with several water users in the area. There is no irrigation water presently diverted at Lower Granite Dam for use in the area. The primary irrigation use in the system is the reservoir behind Ice Harbor Dam. Transporting the estimated 700 cfs (1390 acrefeet/day = 500,000 acrefeet/year) required for the current irrigation demand from the Lewiston area to the Ice Harbor area is a monumental task.
The EFFECTS Water Supply -- FR/EIS Summary (February 2002)
Water from the lower Snake River is used to irrigate crops, supply backup water for municipal systems and industries, enhance wildlife habitat, and water livestock. In the counties adjacent to the four lower Snake River reservoirs, 19 percent of the agricultural land is irrigated, most of which is located in Franklin (68 percent) and Walla Walla (29 percent) counties. Nearly all of the water for irrigation comes from 12 pumping stations near Ice Harbor Dam. There are also eight municipal and industrial pumping stations along the Snake River. Some additional irrigation water comes from wells, some of which are influenced by the reservoirs.
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Alternative 4--Dam Breaching
If the dams were breached, pumping station intakes that currently withdraw water from the reservoirs would be above the new water level. Pump modifications would be required for Snake River water to be pumped for irrigation and other water uses. If irrigation water from the Snake River was no longer available, the economic impact in terms of lowered farmland value could equal $134,240,000. Pump modification costs calculated for municipal and other industrial water users were estimated to range from $11,514,000 to $55,214,000. Irrigation wells within one mile of the reservoirs could also require modifications, which were estimated to cost $56,447,000.
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Under Alternative 4--Dam Breaching, increased salmon runs would benefit the tribes, as would the exposure of approximately 14,000 acres of currently inundated lands. Conversely, Hispanic workers employed on farms irrigated from the Ice Harbor reservoir would be disproportionally affected if these farms go out of business as a result of Alternative 4--Dam Breaching.
Irrigation System Modification Plan -- FR/EIS Appendix D Annex O (February 2002)
The area irrigated by the 12 pumping stations totals approximately 15,000 hectares (37,000 acres) of land. Approximately 11 percent of the irrigated acreage is used for fruit trees, 6 percent for grape vineyards, 23 percent for hybrid poplar and cottonwood harvested for pulp for cardboard manufacture, and 46 percent for annual row crops. Approximately 14 percent of the acreage is undefined. A total of 40 percent of the acreage is used for mature tree-like plants that are not capable of surviving a season without irrigation.
Estimated Percentage of Crops by Type (from 2002 FR/EIS) Crop % of Crop Type Cottonwood/Poplar 23.2 Potatoes 14.9 Field Corn 13.5 Fruit Tree Orchards 11.1 Wheat 9.5 Vineyards 6.2 Sweet Corn 5.4 Onions 3 Undefined 13.2 Total 100
The primary assumption on which this irrigation system modification is based is that the current water demand must be met by a replacement system and be operational prior to the initiation of the drawdown of the Ice Harbor Reservoir. The system must function through a full range of river stages without interruption. The design, operation, or scheduled maintenance must address the presence of large quantities of suspended sediment in the water for extended periods of time for several irrigation seasons.
O.2.1 Existing Systems
There are seven privately-owned irrigation pumping stations on the Ice Harbor Reservoir. These pumping stations range in size from a peak pumping capacity of 0.2 m3/s (5.6 cfs) to a peak capacity of 7 m3/s (247 cfs). In general, the existing pumping stations draw water through intake screens in the pool and pump the water uphill to corresponding distribution systems. The majority of the pumps are vertical turbine type with a few centrifugal pumps. Without the pool of water created by the Ice Harbor Dam, the intakes to these pumping stations would be completely out of the water and would be unable to lift water from the new, lower water surface.
O.2.2 Discussion of Alternatives
This study team considered several alternative means of providing water to the irrigators. Those alternatives included: 1) relocating the pumping stations to the new shoreline, 2) adding booster pumping stations to pump water from the new shoreline to the existing pumping stations, and 3) building a single large pumping station and distribution system that would serve all of the irrigators.
O.3 Selected Configuration
O.3.1 General Discussion
The selected primary irrigation system is a pressure supply system that withdraws water from one river location and supplies all the distribution systems. An optional feature is to construct a reservoir for sediment and surge control with a main pumping plant and make appropriate modifications to the river intake plant.
The primary irrigation system consists of five main components: 1) a pumping plant at the river, 2) a piping system, 3) connections to existing irrigation systems, 4) secondary pumping plants, and 5) a control system. The plant at the river lifts to the piping system.
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The optional reservoir requires the addition of four main components: 1) a large settling reservoir, 2) a main pumping plant, 3) reconfigured pumps at the river intake plant, and 4) additional supply piping to the reservoir and additional discharge piping from the reservoir. The plant at the river would lift the river water up to the settling reservoir while the main pumping plant would pump from the settling pond into the piping system.
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The pumps in the system must be sized to deliver the quantities of water needed by each irrigator. The size of the motors on the pumps is related to the volume of water being pumped, elevation changes, flow losses in the piping system, and the desired pressure at the ends of the pipe branches. Pipe size can greatly influence flow losses in the system and, thus, the size of the motors needed on the pumps. Large-diameter pipe is desired to reduce motor sizes and power consumption. On the other hand, smaller-diameter piping is desirable to reduce pipe costs for such a long, extensive pipeline. In selecting pipe size and motor size and in determining the number of pumps to use, overall project cost and practicality were considered by thus study team, but only at a cursory level. If the decision is made to drawdown the reservoirs and a pumping system similar to that described below is to be pursued, the cost ramifications should be more carefully reviewed.
Many people are familiar with the Seventh Generation philosophy commonly credited to the Iroquois Confederacy but practiced by many Native nations. The Seventh Generation philosophy mandated that tribal decision makers consider the effects of their actions and decisions for descendents seven generations into the future. There was a clear understanding that everything we do has consequences for something and someone else, reminding us that we are all ultimately connected to creation.