Loading...
HomeMy WebLinkAboutCity of Pilot Point Wind Power & Heat 65% Design - Jul 2017 - REF Grant 7014025May 4, 2015 113-95632 Mr. Patrick Boonstra Intelligent Energy Solutions LLC PO Box 91978 Anchorage, AK 99509 RE: PILOT POINT WIND FEASIBILITY STUDY - NORTHWIND 100 WIND TURBINE Dear Patrick: Golder Associates Inc. (Golder) is pleased to present the results of our geotechnical investigation, laboratory testing, and conceptual level engineering recommendations for the proposed 100-kW Northwind 100 turbine planned for Pilot Point, Alaska. Our services have been conducted in general accordance with our proposal to you dated May 31, 2011. Subsequent to our draft report submittal, the project was apparently not authorized for final design or construction, thus a final report was not requested from Golder. In April 2015, the project was apparently reactivated and Golder was requested to provide a final report based on our draft report geotechnical findings. We have not visited the site since our draft report submittal, thus we cannot verify current site conditions are as described in this submittal. Verification of current site conditions is required for use of our geotechnical recommendations presented herein. 1.0 INTRODUCTION We understand that the city of Pilot Point is considering installing at least one 100-kW Northwind 100 wind turbine near the village. The proposed wind turbine sites were determined by you or the city and are labeled T-1, T-2 and T-3. We understand that T-3 is currently the preferred site. The proposed turbine locations and our test explorations are presented in Figures 1 and 2, and are generally located as follows: Site T-1:is located south of the Airport on the north side of Shangin Road Site T-2:is located south of the Airport on the west side of Caribou Lane Site T-3:is located on a low hilltop northeast of the sewage lagoon Our scope of work was to review readily available existing geotechnical data, observe the test pit excavations at the proposed sites, perform geotechnical laboratory testing on disturbed but representative soil samples, and develop wind turbine tower foundation options. We understand at this time only one turbine unit is under consideration but additional turbine units may be installed pending funding. If additional wind turbines are authorized, additional site-specific geotechnical work may be required. We must be contacted prior to use of the data and engineering recommendations presented herein for any other proposed wind turbine systems. Turbine tower base loads (unfactored) were provided with your July 5, 2011 email to us for a 120 foot tower and a 68.5 foot diameter rotor. General foundation loads provided to us are as follows, and each are resultants applied at the base of the tower: Shear, Horizontal: 28.0 kips Pilot Point Wind Turbine Golder Associates Inc. 2121 Abbott Road, Suite 100 Anchorage, AK 99507 USA Tel: (907) 344-6001 Fax: (907) 344-6011 www.golder.com Golder Associates: Operations in Africa, Asia, Australasia, Europe, North America and South America Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation Patrick Boonstra May 4, 2015 Intelligent Energy Systems LLC 2 113-95632 Vertical Compression: 43.6 kips Overturning Moment: 2,471 kip-ft Torsion: 23.2 kip-ft Based on the provided tower base loads, overturning at the tower base will control the foundation design. 2.0 REGIONAL GEOLOGIC AND CLIMATE SETTING 2.1 Regional Geology Pilot Point is located on the northern coast of the Alaska Peninsula, on the north-east central shore of Ugashik Bay about 84 air-miles south of King Salmon and 368 air-miles southwest of Anchorage (see Figure 1). The surficial geology at Pilot Point is comprised of beach deposits with glacial outwash and moraine deposits. Beach deposits, running parallel to the coast line, are primarily of fine to coarse grained reworked glacial deposits. Moraine deposits are of glacial origin characterized by unstratified silt, sand and gravel with knob and kettle features predominant on the surface forming small lakes (Detterman et al., 1987). The moraines may also contain larger dimension cobbles, boulders, and glacial erratics. These depositional features have been modified by recent surface erosion and geomorphic processes. The region is mapped as “generally free of permafrost” (Ferians, 1965) with a few small isolated masses of permafrost in the highlands and lowlands. Permafrost may be present under thicker peat or organic silt deposits or along windswept ridges and areas of topographic relief. Permafrost, if encountered, would be expected to be warm permafrost that is most likely in a thermally degrading state. Permafrost has not been encountered within the city of Pilot Point (DCED, 2008). 2.2 Regional Climate Information The climate at Pilot Point is maritime due to its coastal location. According to the Community Data Base (DCED, 2008) the local weather is characteristically cool, humid, and windy. The average precipitation is approximately 19 inches, including 38 inches of snowfall. The average summer temperature range is 41 to 60°F, and the average winter temperature range is 20°to 37°F. The winds are commonly from the east or the southwest at an average of 14 miles per hour. Low clouds and fog restrict the ability to travel to and from the city by plane. 3.0 SITE CONDITIONS The proposed wind turbine sites T-1 and T-2 are located south of the airport on the north and south sides of Shangin Road. Both locations are on a glacial moraine that is gently sloping to the north and covered with tundra vegetation and surface organic soils. The proposed wind turbine site T-3 is located on a topographic rise northeast of the sewage lagoon. This area is also covered with tundra vegetation. No significant access issues were encountered during the geotechnical field exploration effort. 4.0 EXISTING GEOTECHNICAL INFORMATION We reviewed geotechnical data from an area near the proposed wind turbine site. Post Office: In October 1999, LCMF (now UMIAQ LLC) conducted a subsurface excavation near the Post Office. One borehole was drilled to 12 feet deep with small geotechnical exploration equipment. The borehole log shows a surficial organic mat about one foot thick that overlies a reported clay layer that extended to the base of the exploration, 12 feet below ground surface. Pilot Point Wind Turbine Patrick Boonstra May 4, 2015 Intelligent Energy Systems LLC 3 113-95632 Water Well Logs:The Alaska Department of Natural Resources (ADNR) maintains a water well log database (WELTS). Review of the database found seven water well logs for Pilot Point with approximate locations noted in Figure 2. The water well logs are not considered suitable for geotechnical engineering or design. However, the logs provide a general indication of subsurface conditions. In general, the water well logs indicate clayey materials with boulders, cobbles and ‘rock’ are present in the area. These coarser grained materials may impact deep foundation options for the wind turbines. 5.0 GEOTECHNICAL INVESTIGATION 5.1 Field Exploration The geotechnical field investigation was conducted on June 8 and 9, 2011. Three potential wind turbine locations were identified either by IES or city representatives. IES and Golder representatives attempted to travel together to Pilot Point but flight restrictions did not allow IES representatives to accompany us. IES previously conducted site visits to coordinate the turbine location along the eastern side of the city, identified as site T-3 in this report. IES obtained access authorization for the geotechnical work and subcontracted for the excavation services. Upon our arrival, the city requested we advance test pits at two additional sites identified at T-1 and T-2 in this report. Access was granted by the city for this work and the excavation services were provided through IES’s subcontract with the city. Prior to commencing field explorations, statewide utility locates were completed by Golder and Golder’s on-site representative coordinated local utility locates with Pilot Point utility representatives. No underground utility conflicts were reported through the statewide system or local representatives at the proposed test pit locations. Five test pits were excavated at three proposed wind turbine locations, TP-1 and TP-2 at turbine location T-1, TP-3 at turbine location T-2, TP-4 and TP-5 at turbine location T-3. The proposed wind turbine locations were not survey located in the field. The test pit locations were located in the field using a handheld GPS instrument within the accuracy of the instrumentation based on locations provided to us by IES or the city. The test pit locations should be considered approximate relative to the provided figures and the proposed wind turbine locations. The test pits were advanced to between 13 and 16 feet below existing grade at the turbine sites. The test pits were excavated with a Link Belt 4300 Excavator owned and operated by the city of Pilot Point. The test pits were logged and sampled by a Mr. Nick Owens, staff engineer with Golder. Disturbed, but representative soil samples were obtained directly from the test pit walls up to a depth of four feet then from the excavator bucket below four feet depth. All samples were visually classified in the field with representative portions retained and sealed in polyethylene bags to preserve their natural moisture content. All retained soil samples were delivered to our Anchorage laboratory for additional soil classification and index property testing. Geographic coordinates of the test pit locations were recorded with a handheld GPS instrument after each test pit excavation was complete. The test pits encountered numerous cobbles and boulders which were not possible to retain and transport to our laboratory for geotechnical testing. The nature, extent, and estimated amount of the larger dimensioned materials are noted on our test pit logs and are also provided with summary photographs. One-inch diameter field-slotted PVC pipe was installed in test pits TP-1, TP-3, TP-4, and TP-5 prior to backfilling with excavated material in order to facilitate groundwater measurements. The soils have been classified according to the Unified Soils Classification System (USCS) according to ASTM standard D- 2487-05 as described in Figure A-1. The record of test pit logs are presented in Appendix A. 5.2 Laboratory Testing In the laboratory, recovered samples were visually re-examined to verify field classifications and to select samples for geotechnical index testing. Testing included natural moisture content, grain size distribution, Pilot Point Wind Turbine Patrick Boonstra May 4, 2015 Intelligent Energy Systems LLC 4 113-95632 hydrometer analysis, and percent passing the 0.075mm (US No. 200) standard sieve size. Grain size distribution plots are shown in Appendix B. Please note the laboratory testing was conducted on retained soil samples with the larger dimensioned material (cobbles and boulders) removed and screened to a minus 3-inch material). Laboratory test results are shown graphically on the test pit logs and are tabulated in the Sample Summary; Appendix C. 6.0 SUBSURFACE CONDITIONS 6.1 Subsurface Soil Conditions The subsurface soil conditions observed at the proposed wind turbine locations T-1 and T-2 consisted primarily of a surface organic mat about one foot thick overlying a soft to medium stiff organic silt ranging 0.5 to 5 feet below grade. Below the organic silt was a layer of dense gravel and sand containing boulders up to 36 inches in nominal diameter throughout the depth of the excavations. Numerous boulders were encountered at these two proposed tower sites. The subsurface soil conditions observed at location T-3 consisted of a thin surface organic mat about one foot thick overlying a soft to medium stiff organic silt extending 2 to 3.5 feet below grade. Below the organic silt was a layer of gravel with sand ranging 8 to 9 feet below grade. Below the gravel with sand was a layer of silty sand that continued through the depth of excavation. Larger dimensioned materials, cobbles and boulders, were present at this site, but in significantly lower concentrations relative to sites T- 1 and T-2. Groundwater measurements were taken using a groundwater indicator that was placed inside the slotted one-inch diameter PVC installed within the replaced excavated material. Groundwater was not observed in any of the test pits prior to our departure. Permafrost or indications of deep seated seasonal frost were not encountered in any of the exploration test pits. 6.2 Laboratory Test Results Soil moisture content was measured in all recovered soil samples. Average soil moisture content, as a percent of dry weight, was 110-percent for peat samples, 45-percent for organic silt samples, and 6- percent for tested granular materials. Grain size distribution tests were conducted on select samples recovered from the subsurface exploration, including a determination of the percent passing the 0.02 mm size used to determine soil frost classification. Grain size distribution testing was conducted on representative samples from approximately 4 to 12 feet below existing grade, the expected depth range for a shallow tower foundation option. Oversized material, particles larger than 3 inch nominal diameter was removed prior to conducting the grain size distribution in accordance with ASTM D-4220 recommended practice. Based on grain size distribution data, fines content (material passing the US No. 200 standard sieve) ranged from approximately 9 to 26-percent of dry weight. Hydrometer analyses were conducted on two soil samples to aid with soil frost classification. Based on the hydrometer results, the percentage passing 0.02-mm nominal gain size diameter ranged from approximately 5 to 17 percent. The grain size and hydrometer data indicate the in-place materials within the expected tower shallow foundation depth range are considered frost susceptible. Frost susceptible classifications range from “S1”, Slightly Frost Susceptible (within the poorly-graded gravel tested) to “F3” Moderately Frost Susceptible within silty sand tested based on the US Army Corps of Engineers soil frost classification system (as described in Figure A-2). Pilot Point Wind Turbine Patrick Boonstra May 4, 2015 Intelligent Energy Systems LLC 5 113-95632 7.0 DISCUSSION The three explored sites generally encountered granular soils below a surface organic material. In general, the encountered granular materials are considered suitable bearing material for a shallow foundation option for the tower provided site preparation methods discussed below are adopted. The in- place soils at the expected shallow tower foundation depth range are frost susceptible and frost protection measures are advised to reduce the potential for seasonal frost penetration under the tower foundation. Two deep foundation options are provided. First, a larger diameter helical pile foundation system can be considered. Helical piles would typically require 25 to 30 feet embedment to develop axial and lateral capacity for the wind turbine units being considered. As noted, our test pit explorations did not extend to the depths expected for a helical pile foundation, thus some uncertainty should be expected at all proposed sites regarding subsurface conditions below the exploration depths. The water well logs indicate a range of subsurface conditions can be expected below 15 feet ranging from clayey soils to cobbles and boulders. Thus, if a helical pile foundation option is being considered, the owner and contractor must recognize and accept the potential risks associated with advancing a deep foundation below the depths of our test pit excavations. Specific to helical piles, proposed tower sites T-1 and T-2 (test pits TP-3, 4 and 5) encountered considerable amounts of larger dimensioned boulders 36-inch nominal diameter and larger. Material this large will significantly impact helical pile installation and may severely damage the helices even with predrilling. It is our opinion helical piles should not be considered for these two sites. If the owner desires to use a helical pile foundation at these two sites, we recommend the owner conduct further subsurface assessment, engineering analysis, and discussion with the helical pile manufacturer constraints regarding installation in cobbles and boulders. Site T-3 (test pits TP-1 and 2) did not encounter as numerous larger-dimensioned boulders, but cobbles and some boulders were noted in the test pits. As with site T-1 and T-2, these larger dimensioned materials can significantly impact helical pile installation. For site T-3, we consider a helical pile option feasible, but not without installation risk due to the potential to encounter larger dimensioned subsurface materials (cobbles and boulders). Again, we do not recommend use of helical piles at this site without additional site assessment, engineering analysis, and coordination with the helical pile manufacturer regarding installation of helical piles in cobbles and boulders. Of particular concern is the requirement to maintain precise location for the helical piles within the foundation system. If a helical pile is able to penetrate the cobbles and boulders, the larger dimensioned material may deflect and force the helical pile from the desired target location. The amount of deflection can be considerable and may not meet the design tolerances. Driven pile is another deep foundation option for the wind turbines. Driven piles will need to be embedded below the depth of the test pit excavations into undetermined materials. Based on the WELTS well log data, it appears significant thicknesses of cohesive soil (clay) may be present within reasonably expected pile embedment depths. If a driven pile option is being considered, we advise conducting deep geotechnical soil borings at the proposed pile locations to determine the nature and extent of subsurface materials for a pile foundation design. WELTS data, while useful, is not considered adequate for geotechnical design. Also, the presence of boulders may significantly impact pile foundation installation with the potential to damage the piles during driving. The larger-dimensioned materials will prohibit use of displacement (closed end) piles, thus H-Piles or open end pipe piles will most likely be required, particularly at tower site T-1 and T-2. Predrilling and other methods may be required for pipe plies to achieve embedment through the larger-dimensioned materials. Predrilling for H-piles is not advised. Pilot Point Wind Turbine Patrick Boonstra May 4, 2015 Intelligent Energy Systems LLC 6 113-95632 8.0 FOUNDATION RECOMMENDATIONS Based on the encountered subsurface materials and our discussions regarding the desire to reduce foundation risk, we recommend a shallow gravity foundation system for the wind turbines. If helical piles and driven piles are being considered as foundation elements, we must be contacted since additional site exploration and geotechnical engineering analysis is necessary. For foundation design, we consider the controlling load the base overturning moment, roughly 2,500 kip-ft (unfactored) as provided by the manufacturer. Our analysis considered the orientation of this base overturning moment normal and orthogonal to the foundation geometry. The orientation will impact the effective bearing area and required soil bearing pressures for the shallow gravity option. For the shallow gravity foundation option, we have assumed either a cast-in-place reinforced concrete foundation pad, or a post-tensioned, pre-cast foundation system will be used. For the shallow gravity foundation option, we advise avoiding development of tension load state under the foundation. We have not tested or verified potential locally available concrete aggregate sources under this scope of services. The availability and suitability of local sources for concrete aggregate and structural fill will require confirmation by the design team. 8.1 Shallow Gravity Foundation Option This option will rely on a reinforced concrete mat to develop adequate axial, overturn, and lateral resistance against the design loads and moments. This option is considered suitable for all three explored sites, provided proper site preparations are followed. 8.1.1 Site Preparation All organic, deleterious, and silty material must be removed under the tower foundation. The exposed subgrade must be proof compacted. Any soft or yielding surfaces noted during proof compaction must be removed to a dense, non-yielding surface and replaced with structural fill. The tower foundation footprint excavation should extend at least five (5) feet beyond the tower foundation perimeter to allow for overexcavation and structural fill placement. The excavation should be sufficiently large and sloped or shored to permit safe access for equipment and labor as well as meet all required OSHA standards. Proof compaction should achieve at least 95 percent of the maximum dry density as determined by test method ASTM D-1557. Vibratory compaction equipment is required and soil moisture conditioning may be necessary. At proposed tower sites T-1 and T-2, significant quantities of boulders were encountered in our test pit explorations. Boulders are expected at the probable depths of the shallow foundation. If encountered, all material greater than 8-inch in nominal dimension must be removed to at least 12 inches below the base of the structure fill under the proposed concrete foundation. Careful observation is required at the base of the overexcavation if boulders require removal to assure voids, loose material, or unacceptable bearing conditions are not present prior to placement of structural fill. Proof compaction coupled with visual inspection by an experienced geotechnical engineer or engineering geologist is advised to determine if unacceptable voids or loose materials are present at the base of the excavation. At proposed tower site T-3, silty sands may be encountered at or near the foundation depth. Silty sand, if encountered, should be overexcavated at least 24 inches below the foundation depth, proof compacted and structural fill placed above the silty sand. If silty sand is present at the base of the excavation, a geotextile separation fabric similar to Geotex 801 is recommended prior to placement of structural fill. If granular soils (gravel and sand) are present at the base of the excavation, a geotextile separation fabric is not considered necessary. Groundwater or surface water should not be allowed to accumulate in foundation excavations until the foundations are backfilled to final grades. There is potential for surface water, precipitation, and/or Pilot Point Wind Turbine Patrick Boonstra May 4, 2015 Intelligent Energy Systems LLC 7 113-95632 groundwater to enter the tower foundation excavations and construction planning should include methods to control water that may enter the tower foundation excavations. SWPPP and other discharge regulations should be carefully planned as part of the construction effort. Dewatering may also be necessary to control groundwater infiltration. Water ponding within the excavation footprint as surface water or groundwater infiltration may significantly increase soil slope instability. Thus all ponded water must be removed from the base of the excavation. If groundwater seepage is present, additional groundwater dewatering methods may be required to control pore pressure buildup including, but not limited to, well points. Water control is considered an essential design and constructability issue. 8.1.2 Structural Fill Structural fill should consist of clean, well graded sand and gravel meeting Non Frost Susceptible (NFS) or Possible Frost Susceptible (PFS) classification as determined by the US Army Corps of Engineers. If local borrow sources cannot develop NFS or PFS material, Slightly Frost Susceptible (S1) gravel aggregate can be used, but some additional frost related movements can occur and some constructability issues may arise due to the increased fines content in S1 material. Structural fill should be in general accordance with the Alaska Department of Transportation and Public Facilities Standard Specifications for Highway Construction (ADOT&PF, 2015) Select Type A Material with a limitation of 3-inch maximum particle size. For all proposed tower sites, structural fill should extend at least 24 inches below the base of the concrete mat foundation and seat on proof-compacted granular, mineral subbase material. All structural fill under the tower foundation must extend at least three feet laterally in all directions from the tower foundation perimeter then slope at a 1.5H:1V (horizontal:vertical), or shallower, from the top of the fill section to the prepared subgrade, provided the structural fill is fully contained along the undisturbed excavation sidewalls. If not, side slopes of 2H:1V or shallower is required. Backfill placed above or on top of the base of the concrete foundation should be compacted granular, mineral material meeting ADOT&PF Standard Specifications for Select Type A Material with a limitation of 3-inch maximum particle size. 8.2 Allowable Bearing Capacity, Estimated Settlement, Lateral Resistance Soil bearing pressures were derived from design axial compressive loads, overturning moment at the tower base and allowances for concrete foundation and fill placed above the foundation. The large overturn moment will develop an eccentric load state along the base of the foundation. Our analysis was based on not developing a tension load state to occur under the foundation during the design transient loads. We also considered the orientation of the overturn moment relative to the foundation as normal (one-way eccentricity) and orthogonal (two-way eccentricity). Based on the provided design loads and design constraints, we recommend the reinforced gravity foundation be at least 20 feet square (400 square feet) with the base of the concrete mat embedded at least nine (9) feet below finish grade. Final foundation dimensions should be determined during detailed design. The subbase under the mat foundation must be prepared as discussed above. Free-draining, granular, mineral sand and gravel (preferably structural fill) should be placed and compacted above the foundation mat to final grade. Compaction recommendations for structural fill should be followed for material placed above the concrete mat. Assuming our recommendations for site preparation and a shallow foundation are followed, an allowable bearing capacity of 3,800 pounds per square foot (psf) is permitted for sustained load states. The allowable bearing capacity can be increased by one-third for the short term, transient load states. The axial compression load should also include the soil backfill above the foundation mat. Estimated settlements for the tower foundations bearing on structural fill are expected to be less than 1 inch total with ½ inch differential, provided our geotechnical recommendations are followed. The majority Pilot Point Wind Turbine Patrick Boonstra May 4, 2015 Intelligent Energy Systems LLC 8 113-95632 of the total settlement is expected to occur concurrent with the tower construction and initial loading, while differential settlement is likely to result from repeated eccentric loading and over time. Lateral resistance will be developed as frictional resistance along the concrete mat/structural fill interface. A friction factor of 0.2 times the axial dead load can be used for an allowable frictional lateral resistance. Additional lateral capacity will be developed through passive resistance developed along the vertical face of the tower mat foundation or a keyway (if needed) installed along the base of the concrete mat. Assuming level grades and no groundwater influence, surcharge or seismic loads, an equivalent fluid pressure of 200 pounds per square foot per foot (psf/ft) can be used for determining the passive resistance at the base of the mat foundation. Similar values can be used to determine torsion resistance. Developing full passive resistance will require soil movement, thus some total and differential movement of the mat foundation should be expected. 8.2.1 Seasonal Frost Considerations Seasonal frost is expected to advance 3 to 4 feet below grade at the site. However, deeper frost penetration can be expected through the concrete or steel tower members as well as through lower soil moisture content sand and gravel backfill. However, with the recommended 9 foot embedment depth, the likelihood of seasonal frost penetration below the concrete foundation is considered low. Coupled with the 24 inches of NFS to S1 fill directly under the foundation mat, we do not see the need for rigid insulation thermal protection for this site. 8.2.2 Constructability Considerations Fill installed above the mat foundation should be compacted granular material, and should extend to surrounding the grade with a final grade that promotes surface water drainage away from the tower. Surface vegetation should be considered for non gravel pad areas. We understand that a winter construction program is not expected at this time. If a winter or freezing air temperature construction schedule is planned, we should be contacted to augment our recommendations for cold weather construction practices. Under no circumstance is frozen material permitted for use as structural fill or fill placed above the mat foundation. All fill must be placed and compacted in a fully thawed state. It is recommended that the location of the tower foundation avoid any ground that may have been disturbed by the test pits. Additional subgrade improvement may be needed if the tower foundations are installed over our test pits since the test pits were not compacted during backfilling. Appurtenances to the tower base should be designed with flexible connections to allow for seasonal frost movements. Rigid connections between the surrounding soil and the tower or the tower base should be avoided. 9.0 LIMITATIONS AND USE OF REPORT The geotechnical recommendations provided herein are considered conceptual and are provided for site planning. We must review the civil and structural engineering design elements if the project advances. Under no circumstances should our geotechnical recommendations provided herein be used for final design, bid documents, or construction without our review and coordination with the design team, developer and owner. This report was prepared exclusive for the use of Intelligent Energy Solutions and the owners of the proposed facility. If there are significant changes in nature, design, or location of the facility, we should be notified so that we may review our conclusions and recommendations in light of the proposed changes and provide written modification or verification of the changes. Pilot Point Wind Turbine REFERENCES Alaska Department of Transportation and Public Facilities (ADOT&PF), 2015, Standard Specifications for Highway Construction. Department of Commerce, Community, and Economic Development (DCED). 2008 Community Data Base Online (http://www.commerce.state.ak.us/dca/commdb/CIS.cfm). State of Alaska, Division of Community and Regional Affairs. Detterman, R.I., Wilson, F.H., Young, M.E., and Miller, T.P., 1987, Quaternary Geologic Map of the Ugashik Bristol Bay, and Western Part of Karlik Quadrangle, Alaska. Prepared for the United States Department of the Interior, U.S. Geologic Survey, Miscellaneous Investigation Series, Map I-1801, and Open-File Report 2004-1009. Ferrians, O.J., Jr., 1965, Permafrost Map of Alaska: U.S. Geological Survey Miscellaneous Geological Investigations Map I-445, Scale 1:2,500,000. FIGURES TP-01TP-02TP-03TP-05TP-04340003400134002340033400434005TRossSCALE0FEET150015002---- ----APG/TER 4/24/15TER 4/24/15RAM 4/27/151 ----FIG.IES / PILOT POINT WIND FEASIBILITY / AKLOCATION MAPPILOT POINT WIND FEASIBILITYPILOT POINT, AKCHECKREVIEWDESIGNCADDSCALEFILE No.TITLEAS SHOWNREV.INSET MAP1.) BASEMAP AND AIRPHOTO PROVIDED BYALASKA DEPARTMENT OF COMMERCE,COMMUNITY, AND ECONOMIIC DEVELOPMENTREFERENCEGOLDER TEST PIT LOCATION ANDNUMBERLEGENDTP-0134000WELTS WATER WELL LOCATIONAND REFERENCE IDTRADITIONALCOUNCIL WELLLCMFLCMFPROPOSED POST OFFICEBOREHOLE (LCMF)PROPOSED TOWER SITE LOCATIONT-XT-3T-2T-11.) ALL LOCATIONS APPROXIMATENOTENTS APPENDIX A LOGS OF TEST PITS TP-1 THROUGH TP-5 APPENDIX B GRAIN SIZE DISTRIBUTIONS APPENDIX C SUMMARY OF SAMPLES GEN 3GEN 2GEN 1RADIATOR 1 RADIATOR 2LRB-1PMP-1HX-1HX-2P-HR1(4 GPM)P-HR2(35 GPM)P-HR3(40 GPM)P-HR4(7 GPM)PMP-X3/4" HGS & HGR TO FIREHALL UNIT HEATERTO/FROM SCHOOLHEATING SYSTEMPOWER PLANTFIRE HALLSCHOOL3/4" HGS & HGR TO CONTROLROOM CABINET UNIT HEATER2"3"2"3"NOTE: EQUIPMENT AND PIPING SHOWN IN LIGHT LINEWEIGHTIS EXISTING. EQUIPMENT AND PIPING SHOWN IN HEAVYLINEWEIGHT IS NEW WORK.2" HGS & HGR (BURIED)2" HGS & HGR (BURIED)2" HGR (BURIED)SCALE:1M1.0FIRE HALL PLAN1/4" = 1'-0"M1.0SCALE:2M1.0PIPING SCHEMATICNONEConsulting EngineerChris LinfordChristopher L. LinfordME-5718PILOT POINTLOAD REGULATING BOILERPilot Point, Alaska United States Department of the Interior U.S. FISH AND WILDLIFE SERVICE Anchorage Fish and Wildlife Field Office 4700 BLM Road Anchorage, Alaska 99507 In Reply Refer To: FWS/AFES/AFWFO April 20, 2017 EMAILED TO: Mr. Patrick Boonstra Intelligent Energy Systems, LLC 110 West 15th Avenue, Suite B Anchorage, Alaska 99501 Subject: Wind to Heat, Chefornak and Pilot Point, Alaska (Consultation 2017-I-0156) Dear Ms. Taylor: Thank you for requesting section 7 consultation with the U.S. Fish and Wildlife Service (Service), pursuant to the Endangered Species Act of 1973 (16 U.S.C. 1531 et seq., as amended; ESA) by correspondence received April 7, 2017. The United States Department of Agriculture Rural Utility Service (USDA-RUS) is requesting informal consultation on two proposed wind turbine projects to heat homes in Chefornak and Pilot Point, Alaska. The USDA-RUS has designated Intelligent Energy Systems, LLC as their non-Federal representative for the purpose of this consultation. The USDA-RUS has determined that, with implementation of the avoidance and minimization measures listed below, the action may affect, but is not likely to adversely affect, the federally threatened Steller’s eider (Polysticta stelleri) and spectacled eider (Somateria fischeri). The Chefornak project proposes 3 wind turbines, sited 0.4 kilometer east of the Village of Chefornak. The project includes the following components: 24-meter tall lattice towers with 17-meter blades for total heights of 32.5 meters, blade sweep, 15.5 meters from the ground to 32.5 meters in height, access boardwalk from the 3 turbines, 0.4 kilometer long to east end of the village, power placed under the boardwalk constructed in late winter on frozen ground. Mr. Patrick Boonstra (2017-I-0156) 2 The Pilot Point project consists of one monopole tower capable of been raised and lowered using local equipment and labor. It is sited within the existing wind farm for the City of Pilot Point and would include the following components: • 31-meter tall monopole tower with a 21-meter diameter blade for total blade height of 42.3 meters, • blade sweep, 21.9 meters from the ground to 42.3 meters in height • 8 guy wires begin below blades, approximately 21.9 meters from the ground, • fencing around project, • buried power • constructed in late fall or early winter, accessed by a City maintained road The Chefornak wind project is about 10 kilometers (6 miles) inland, about 0.4 kilometer (0.25 mile) from the existing village of Chefornak. The village is surrounded by undeveloped coastal wetland habitat. Spectacled eiders may nest up to 14.5 kilometers (9 miles) inland and are known to breed along the coast in this area. The action area is located at the edge of spectacled eider normal range inland. The Pilot Point wind project is about 11.25 kilometers (7 miles) inland from the coast, and about 2.4 kilometers (1.5 miles) inland from Ugashik Bay. Steller’s eiders utilize Ugashik Bay for spring staging (Rosenberg et al. 2011). Surveys also indicate this area of the Alaska Peninsula is important for many other migratory birds as well, including king eider (Somateria spectabilis), common eider (S. mollissima), emperor geese (Chen canagica), long-tailed duck (Clangula hyemalis), and black scoter (Melanitta americana) (Dau and Mallek 2006; Larned 2005). Studies of the flight patterns of various species of eiders indicate they normally travel 1.5 meters to 15 meters over the water and do not generally travel over land (Day et al. 2003). However, they have been known to fly overland in breeding areas and carcasses of eider have been found under towers and power lines, thus we conclude that they sometimes fly over land, under certain conditions, and may be vulnerable to collisions with towers and power lines. The following measures have been incorporated into the project to reduce the potential for impacts to listed eiders. The site has been selected in a location near existing disturbed areas, the existing wind farm and the village. Constructing the towers and turbines near existing development may deter birds from using the area. There will not be overhead power lines installed for the proposed turbines. Guy lines used to support the tower will have bird deterrent devices attached. Bird diverters will be kept in working order and will be repaired or replaced during inspections. Birds may be attracted to lights on or near the coastline, especially at night or during periods of low visibility. To avoid attracting birds to the towers, they will not be lit. If it becomes necessary to light the towers or turbines in the future, only strobe lighting will be used, which is thought to be less attractive than steady burning lights. Mr. Patrick Boonstra (2017-I-0156) 3 No new ground lighting is planned, but if additional ground lighting is needed near the towers/turbines in the future, the lights will be shielded downward to reduce visibility and possible attraction to birds in flight. During turbine inspections the site and surrounding area will be searched for carcasses, piles of feathers or piles of hollow bones around all towers and guy wires to identify whether collisions are occurring. The potential for collision of a listed eider with the proposed projects is low because the locations of the turbines are inland, near existing facilities, and are not located in the flight path eiders would most likely use. Additionally, given the assumption that only 1 percent of Steller’s eiders in the action area belong to the listed population, the probability that a listed eider will strike a tower or guy wire is further reduced. After reviewing the proposed actions and the likely effects, the Service concurs with the USDA- RUS’s determination that activities associated with the two proposed wind turbine projects in Chefornak and Pilot Point may affect but are not likely to adversely affect listed species or their critical habitat. We have reached this conclusion based on the avoidance measures that will be implemented to avoid potential harm from disturbance to both spectacled and Steller’s eiders. Our concurrence relates only to federally listed or proposed species and/or designated or proposed critical habitat under our jurisdiction. It does not address species under the jurisdiction of National Marine Fisheries Service, or responsibilities under the Migratory Bird Treaty Act, Marine Mammal Protection Act, Clean Water Act, Fish and Wildlife Coordination Act, National Environmental Policy Act, Bald and Golden Eagle Protection Act, or other legislation. In view of this concurrence, requirements of section 7 of the ESA have been satisfied. However, this letter does not authorize take of listed species. Injured or dead spectacled and Steller’s eiders must be reported as soon as possible (i.e., within 24 hours unless there are extenuating circumstances) to the Service’s Office of Law Enforcement at 877-535-1795 and to the Anchorage Field Office at 907-271-2888. Obligations under section 7 of the ESA must be reconsidered if new information reveals project impacts that may affect listed species or critical habitat in a manner not previously considered, if this action is subsequently modified in a manner which was not considered in this assessment, or if a new species is listed or critical habitat is designated that may be affected by the proposed action. Additional Recommendations Migratory birds can also suffer significant mortality from collisions with towers, blades, and associated infrastructure such as guy wires. The Migratory Bird Treaty Act (MBTA) prohibits the taking, killing, possession, transportation, and importation of migratory birds, their eggs, parts, and nests, except when specifically authorized by the Department of the Interior. While the MBTA has no provision for allowing unauthorized take, it must be recognized that some birds may be killed at structures such as wind turbines even if all reasonable measures to avoid such strikes are implemented. If project proponents do their due diligence to avoid and minimize impacts to migratory birds, it can demonstrate a good faith effort, which may be viewed favorably if unanticipated effects occur. Mr. Patrick Boonstra (2017-I-0156) 4 The following recommendations are voluntary measures that if adopted, will further reduce the possibility that migratory birds would be harmed by installation or operation of the towers or turbines: Avoid clearing any previously undisturbed ground cover or vegetation during the nesting season. The Service always recommends integrating monitoring and adaptive management planning into wind projects. These measures may be necessary components of the project when the likelihood of collision is high due to the size of a project or its specific location. Report sick or dead migratory birds to the Alaska Sick or Dead Bird Hotline at 866-527- 3358, the Alaska Department of Fish and Game, Office of the State Wildlife Veterinarian at 907-328-8354 or DFG.DWC.VET@alaska.gov. If a carcass is found, note the location, date, and the condition. To keep yourself safe, do not touch the animal. If possible, take pictures and note answers to the following questions: o How long has it been dead? o Are all body parts present, and intact? o Is there any evidence of the injury? o Where is it in relation to structures overhead? o What species of bird is it? If you don’t know, try to determine what type of bird (e.g.,waterfowl, song bird, shorebird, or raptor). o Is there any reason to think the bird died another way, (e.g., was shot or was found beneath a large nest)? Thank you for your cooperation in meeting our joint responsibilities under the ESA. For more information or if you have any questions please contact Ms. Jennifer Spegon at 907-271-2768 or at jennifer_j_spegon@fws.gov and refer to consultation number 2017-I-0156. Sincerely, Douglass M. Cooper Chief, Ecological Services Branch Cc: Steve Polacek Robin Meigel Literature Cited Dau, C.P., and E.J. Mallek. 2006. Aerial survey of emperor geese and other waterbirds in southwestern Alaska, Spring 2006. Fairbanks, Alaska, U. S. Fish and Wildlife Service. Day, R.H., J.R. Rose, R.J. Ritchie, J.E. Shook. 2003. Collision potential of eiders and other birds near a proposed windfarm at St. Lawrence Island, October-November 2002. ABR, Inc.-Environmental Research & Services. Fairbanks, Alaska. Larned, W.W. 2005. Steller's eider spring migration surveys southwest Alaska, 2005. U.S. Fish and Wildlife Service, Waterfowl Management, Anchorage, Alaska. Rosenberg, D.H., M. J. Petrula, D. Zwiefelhofer, T. Holmen, D.D. Hill, and J.L. Schamber. 2011. Seasonal movements and distribution of Pacific Steller’s eiders (Polysticta stelleri). Anchorage, Alaska, Alaska Department of Fish and Game:1-5.