US Army Corps of Engineers Omaha District Draft Fort Peck Dam/Fort Peck Lake Project Montana Surplus Water Report Volume 1 Surplus Water Report Appendix A – Environmental Assessment August 2012 THIS PAGE INTENTIONALLY LEFT BLANK FORT PECK DAM/FORT PECK LAKE PROJECT, MONTANA SURPLUS WATER REPORT Omaha District U.S. Army Corps of Engineers August 2012 THIS PAGE INTENTIONALLY LEFT BLANK Fort Peck Dam / Fort Peck Lake, Montana FORT PECK DAM/FORT PECK LAKE MONTANA SURPLUS WATER REPORT August 2012 Prepared By: The U.S. Army Corps of Engineers, Omaha District Omaha, NE Abstract: The Omaha District is proposing to temporarily make available 6,932 acre-feet/year of surplus water (equivalent to 17,816 acre-feet of storage) from the system-wide irrigation storage available at the Fort Peck Dam/Fort Peck Lake Project, Montana to meet municipal and industrial (M&I) water supply needs. Under Section 6 of the Flood Control Act of 1944 (Public Law 78-534), the Secretary of the Army is authorized to make agreements with states, municipalities, private concerns, or individuals for surplus water that may be available at any reservoir under the control of the Department. Terms of the agreements are normally for five (5) years, with an option for a five (5) year extension, subject to recalculation of reimbursement after the initial five (5) year period. This proposed action will allow the Omaha District to enter into surplus water agreements with interested water purveyors and to issue easements for up to the total amount of surplus water to meet regional water needs. During the temporary period the Corps recommends that a comprehensive strategy to address long-term regional water needs be developed that may involve the Administration, Congress and stakeholders. The Proposed Action (temporary use of surplus water) will not impede the capability and function of Fort Peck Dam/Fort Peck Lake to serve its authorized purposes. An Environmental Assessment, which is attached to this Surplus Water Report, identifies the baseline environmental conditions and provides an analysis of potential impacts from the proposed use of surplus water. There are no significant environmental impacts associated with implementing the proposed action. For more information contact: Commander, U.S. Army Corps of Engineers Attn: Ms. Kayla Eckert-Uptmor, Chief, Planning Branch, Omaha District 1616 Capitol Avenue, Omaha, NE 68102-4901 Phone: (402) 995-2693 Fax: (402) 995-2758 Surplus Water Report Cover Sheet Fort Peck Dam / Fort Peck Lake, Montana THIS PAGE INTENTIONALLY LEFT BLANK Surplus Water Report Cover Sheet Fort Peck Dam / Fort Peck Lake, Montana EXECUTIVE SUMMARY The Omaha District, U.S. Army Corps of Engineers (Corps) under the Operation & Maintenance Program has prepared this Fort Peck Dam/Fort Peck Lake, MT Surplus Water Report to identify and quantify whether surplus water is available in the Project, as defined in Section 6 of the 1944 Flood Control Act. Surplus water agreements with water use based on this process may be executed with existing and potential future applicants, pursuant to policy, upon approval of this Report by the Assistant Secretary of the Army (Civil Works) and completion of required NEPA analysis. The term of proposed temporary surplus water use is for a five (5) year period, renewable for an additional five (5) year period, subject to recalculation of reimbursement after the initial five (5) year period. This Surplus Water Report and accompanying Environmental Assessment investigate the engineering and economic feasibility and environmental effects of temporary use of up to 6,932 acre-feet/year of surplus water (17,816 acre-feet of storage) from the Fort Peck Dam/Fort Peck Lake, MT Project. Surplus water, if available, may be used to meet existing and projected municipal and industrial (M&I) water supply needs in the region. The 6,932 acre-feet/year of yield (17,816 acre-feet of storage) evaluated for surplus water use in this report is an estimate that was selected to ensure that an adequate quantity of water was identified to meet the needs of both existing and future M&I water users. This Surplus Water Report will serve as the basis to enter into temporary surplus water agreements. A 10-year study period has been established for this surplus water study. The length of the study period was selected for several reasons. First, surplus water agreements may be executed for a five (5) year period, renewable for an additional five (5) year period. Second, prior to the end of the 10-year study period, the Corps recommends that a comprehensive strategy to address long- term regional water needs be developed that may involve the Administration, Congress and stakeholders. The surplus water agreements executed upon the approval of this Report will serve as measures to address temporary water needs of the region during the 10-year study period. The Fort Peck Dam/Fort Peck Lake Project is a unit of the comprehensive Pick-Sloan Plan for development in the Missouri River Basin. The operation of the upper Missouri River’s six mainstem reservoirs and the lower Missouri River’s levees and navigation channel provides for flood control, navigation, irrigation, hydropower, municipal and industrial water supply, fish and wildlife, water quality, and recreation. The temporary use of 6,932 acre-feet/year of surplus water in Fort Peck Lake would result in additional net annual depletions of 630 acre-feet from the system for the ten year period, beyond existing usage levels. The primary difference between with and without project conditions is that under without project conditions, the additional 630 acre-feet will come from groundwater sources and under with project conditions, withdrawal of the additional 630 acre-feet will come from the Fort Peck Dam/Fort Peck Lake Project. Both conditions assume continuation of existing use sourced from Fort Peck Lake. The Daily Routing Model (DRM), developed during the 1990’s as part of the Master Manual Review and Update Study (Master Manual), was used as an analytical tool in this study to estimate the hydrologic effects that an additional 630 acre-feet of depletions would have at Fort Peck Lake, the other system reservoirs, and free-flowing reaches of the Missouri River. A comparison of DRM simulated water surface elevations, stream flows, and river stages between without project conditions and with project conditions resulting from an additional Surplus Water Report i Fort Peck Dam / Fort Peck Lake, Montana depletion of 630 acre-feet from Fort Peck Lake was performed to assess the magnitude of changes resulting from the proposed temporary use of surplus water from the Project. Modeling results indicate that stage and flow reduction estimates throughout the system are extremely small because the projected net depletion is very small relative to total storage at Fort Peck Lake (18.5 million acre-feet). Because the Missouri River projects are operated as an integrated system taking into account system withdrawals both in and outside of the Federal projects, no changes to system operations will be required as a result of the temporary use of surplus water from the Fort Peck Dam/Fort Peck Lake Project. Under current policy pricing, the annual payment for surplus water would be $38.59 per acre- foot of yield (equivalent to $15.02 per acre-foot of storage) at FY 2012 price levels. In a memorandum dated May 8, 2012, the Assistant Secretary of the Army for Civil Works (ASA CW) directed the Corps of Engineers to initiate action immediately to purse notice and comment rulemaking to establish a nationwide policy for surplus water uses under Section 6 (Attachment 1). Pending completion of rule-making to establish a nationwide policy for surplus water uses under Section 6, surplus water agreements would be entered into at no cost. The term of these agreements would be for a period not to exceed the time needed to conclude the rulemaking process. All users of surplus water would need to enter into new or revised agreements implementing the nationwide policy price once the rule becomes effective. An alternatives analysis was conducted, which assessed non-structural measures (conservation, recycling, and temporary permits to convert irrigation water to industrial use) and structural measures (project modifications to increase storage capacity, temporary use of surplus water including associated infrastructure, groundwater withdrawals including associated infrastructure, and surface water withdrawals including associated infrastructure). The No Action – Next Least Costly Alternative is withdrawal from groundwater. A test of financial feasibility was conducted, which demonstrated that entering into agreements for the use of surplus water from the Fort Peck Dam/Fort Peck Lake Project is a lower cost alternative than the most likely, least costly alternative for providing the needed water supply. An analysis of environmental impacts was conducted using the same DRM outputs that were used to assess impacts to project purposes. The analysis of environmental impacts identified no significant impacts from providing surplus water from the Fort Peck Dam/Fort Peck Lake Project. The temporary use of surplus water assessed in this report is both economically and financially justified and will not affect the authorized purposes of Fort Peck Dam/Fort Peck Lake Project. It is recommended that 6,932 acre-feet/year of yield (equivalent to 17,816 acre-feet of storage) in the Fort Peck Dam/Fort Peck Lake Project be made available for temporary use for municipal and industrial water users. Pending completion of rule-making to establish a nationwide policy for surplus water uses under Section 6, surplus water agreements would be entered into at no cost. Surplus Water Report ii Fort Peck Dam / Fort Peck Lake, Montana THIS PAGE INTENTIONALLY LEFT BLANK Surplus Water Report iii Fort Peck Dam / Fort Peck Lake, Montana TABLE OF CONTENTS EXECUTIVE SUMMARY ............................................................................................................