Off-Channel Reservoir Feasibility Study 2016
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CITY OF BANDON OFF-CHANNEL RESERVOIR FEASIBILITY STUDY 2016 Prepared By: The Dyer Partnership Engineers & Planners, Inc. Engineers, Planners, Surveyors, Water, Wastewater, Transportation Project 101.92 August 2016 Table of Contents SECTION 1: INTRODUCTION ............................................................................ Study Description ........................................................................... 1-1 Scope of Work ............................................................................... 1-2 Feasibility Study Purpose ............................................................... 1-3 Proposed Schedule for Off-Channel Reservoir Construction .......... 1-3 SECTION 2: BACKGROUND ............................................................................. SECTION 3: BIOLOGICAL ASSESSMENT ....................................................... SECTION 4: WATER RIGHTS ........................................................................... Background .................................................................................... 4-1 Proposed Changes to Water Rights ............................................... 4-3 SECTION 5: ARCHAEOLOGICAL AND ENVIRONMENTAL IMPACTS ............ SECTION 6: IMPACTS TO OTHER WATER USERS AND FISH HATCHERY .. SECTION 7: HYDROLOGICAL ANALYSIS ....................................................... Watershed ...................................................................................... 7-1 Climate ........................................................................................... 7-3 Environmental ................................................................................ 7-4 Hydrology and Hydraulics .............................................................. 7-4 Streamflow and Precipitation Relationship ..................................... 7-5 Unit Hydrograph ............................................................................. 7-6 Ferry Creek Rating Curve .............................................................. 7-7 Analysis ......................................................................................... 7-9 Raw Water Diversion and Streamflow Augmentation Schedule ...... 7-9 Future ............................................................................................ 7-11 SECTION 8: GEOTECHNICAL INVESTIGATION .............................................. SECTION 9: PERMITTING ................................................................................. SECTION 10: FEASIBILITY LEVEL COST ESTIMATE ....................................... Purpose ......................................................................................... 10-1 Background Information ................................................................. 10-1 Scope ........................................................................................... 10-1 Basis for Cost Estimate .................................................................. 10-2 Annual Operating and Maintenance Costs ..................................... 10-5 SECTION 11: FUNDING AND RATE ANALYSIS ................................................. Income - Water Rights.................................................................... 11-1 Impact to Ratepayers ..................................................................... 11-1 The Dyer Partnership Engineers & Planners, Inc. i City of Bandon Table of Contents Off-Channel Reservoir Feasibility Study 2016 LIST OF TABLES Table 4.1 Projected Population Growth and Water Need ............................... 4-1 Table 4.2 Existing Water Rights ..................................................................... 4-1 Table 7.1 Physical Characteristics of the Watershed ..................................... 7-2 Table 7.2 Ferry Creek Streamflow Data ......................................................... 7-2 Table 7.3 30-Year Average Climate Data ....................................................... 7-3 Table 7.4 Environmental Data ........................................................................ 7-4 Table 7.5 Average Monthly Streamflow.......................................................... 7-6 Table 7.6 Ferry Creek Streamflow ................................................................. 7-9 Table 7.7 Raw Water Demand ....................................................................... 7-9 Table 7.8 Raw Water Diversion and Streamflow Augmentation ..................... 7-10 Table 10.1 Total Project Cost Estimate ............................................................ 10-3 Table 10.2 Annual O&M Costs ......................................................................... 10-5 LIST OF FIGURES Figure 4.1 Water Rights vs. Max Raw Water Diverted ..................................... 4-2 Figure 4.2 Reservoir Capabilities .................................................................... 4-3 Figure 7.1 Streamflow Response .................................................................... 7-7 Figure 7.2 Ferry Creek Rating Curve .............................................................. 7-8 Figure 7.3 Raw Water Diversion and Streamflow Augmentation Schedule ...... 7-11 Figure 11.1 One Stop Financial Summary......................................................... 11-1 APPENDICES Appendix A: Watershed Delineation Appendix B: Essential Salmon Habitat Appendix C: Flow Precipitation Relationship Appendix D: Unit Hydrograph Appendix E: Rating Curve Appendix F: Diversion Schedule The Dyer Partnership Engineers & Planners, Inc. ii SECTION 1: INTRODUCTION SECTION 1: INTRODUCTION This feasibility study is being prepared to evaluate the Off-Channel Reservoir project in Bandon, Oregon in detail and outlines the steps taken and methods used for completion of the evaluation. This study has been prepared under a grant from the Water Conservation, Reuse and Storage Grant (Grant GA-0101-17) administered by the Oregon Water Resources Department. The objective of the proposed Off-Channel Reservoir project is to establish off-channel storage to insure municipal water supply during low flow or drought conditions from water diverted from Ferry Creek and so that instream flows can be better managed to meet the needs of irrigators and improve late summer fish passage conditions. The proposed reservoir would be located off Cardinal Lane, approximately 0.3 miles southwest of the diversion on Ferry Creek and 0.2 miles west of Geiger Creek Reservoir. The reservoir site would be located entirely on property owned by the City of Bandon. Figure 1.1 shows a vicinity map of Bandon. The proposed reservoir would be designed to store up to a maximum of 100 acre-feet of water diverted from Ferry Creek utilizing the City’s existing point of diversion and pump station. Water would be piped to the reservoir in a new 12-inch diameter pipe that would use the existing utility easement and parallel the City’s treated water main. Water would be diverted from the Ferry Creek during the peak runoff season for raw water storage. The stored raw water would be used to supply municipal needs during tourist season and to directly supplement late summer flows in Ferry and Geiger Creeks. The proposed Off-Channel Reservoir project is expected to benefit multiple uses such as instream flow, water supply, instream and riparian habitat and water quality. The proposed project should allow for water management that would better meet both instream and out-of-stream needs. Climate models suggest that the state’s average summer precipitation will decline in the future and that the wildfire threat is projected to increase. The proposed Off-Channel Reservoir would provide the City resiliency and security for the predicted climate change and the resulting increased wildfire threat. Study Description The following includes a brief description of the scope of work and purpose of the feasibility study. In general, the feasibility study was prepared to identify deficiencies or challenges that would prevent implementation of the project and to more clearly define the benefits and costs associated with implementation and long-term operation of the project. Panoramic view of Lot 2400 after brush was cleared in May 2014. CITY OF BANDON SECTION 1 Off-Channel Reservoir Feasibility Study 2016 Introduction Scope of Work The scope of work approved by Oregon Water Resources Department for development of this feasibility study included the following tasks: Task 1. Complete Water Rights Analysis – This task included determining the means by which surface water will be diverted to fill the proposed reservoir. This task assessed the feasibility of the following options: water right permit amendment; water right transfer; new storage water right permit and new surface water right from reservoir; or use of existing surface water rights. This task included coordinating with Oregon Water Resources Department on how to successfully navigate the administrative issues associated with providing permitted water for the project. Task 2. Complete Biological Assessment, Wetlands Delineation, Environmental Resources Review, Analysis of Permitting Issues – This task included the preparation of a Biological Assessment, following the outline and format of RUS Bulletin 1794-602, Section “3.5.1 Biological Resources Information: Threatened and Endangered Species; Fish and Wildlife: Vegetation”. The assessment included a review of state and federal lists of threatened or endangered species and candidate species that may be affected by the project. The fish, wildlife and vegetation resources