May 3, Kimberly D. Bose, Secretary Federal Energy Regulatory Commission 888 First Street NE, Room 1A Washington, D.C

Transcription

1 1250 West Century Avenue Mailing Address: P.O. Box 5601 Bismarck, ND (701) May 3, 2018 Kimberly D. Bose, Secretary Federal Energy Regulatory Commission 888 First Street NE, Room 1A Washington, D.C Re: WBI Energy Transmission, Inc. Valley Expansion Project Docket No. CP Supplemental Information to Response to Environmental Condition 16 of the Order Issuing Certificate Dear Ms. Bose: WBI Energy Transmission, Inc. (WBI Energy), herewith submits for filing with the Federal Energy Regulatory Commission (FERC) supplemental information to the response to Environmental Condition 16 included in the Appendix of the Order Issuing Certificate filed with the FERC on March 2, 2018 in the above referenced docket. Specifically, WBI Energy is submitting a report on the Felton Creek geotechnical investigation. With the attached information, WBI Energy respectfully requests written approval from the Director of the Office of Energy Projects to commence construction activities within the skip area identified between mileposts 2.0 and 4.1. Any questions regarding this filing should be addressed to the undersigned at (701) Sincerely, /s/ Lori Myerchin Attachments Lori Myerchin Manager, Regulatory Affairs Courtesy Copies: Official Service List Robin Griffin, FERC Project Manager Monika H. Davis, Merjent, Inc.

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4 Valley Expansion Project Felton Creek Geotechnical Investigation Prepared for: WBI Energy Transmission, Inc. Prepared by: May 2018

5 TABLE OF CONTENTS 1.0 INTRODUCTION GEOLOGY HYDROGEOLOGY HYDROGEOLOGIC INVESTIGATION Observations and Analysis CONCLUSIONS REFERENCES... 6 LIST OF TABLES Table 1 Water Levels Recorded by Piezometers LIST OF FIGURES Figure 1 Felton Creek Geotech Investigation LIST OF APPENDICES Appendix A Appendix B Soil Boring Logs Data Logger Graphs for Piezometers W-1A and W-3A i

6 1.0 INTRODUCTION The purpose of this report is to respond to Environmental Condition 16 of the Federal Energy Regulatory Commission (FERC) Order Issuing Certificate (Certificate) for the Valley Expansion Project, issued on February 15, 2018 (FERC February 15, 2018 Order, Appendix 1, Condition 16, p. 26) requires WBI Energy Transmission, Inc. (WBI Energy) to complete a geotechnical investigation of the Valley Expansion Project s (Project s) crossing of Felton Creek (Channelized Ditch No. 45) (Felton Creek crossing) in Clay County, Minnesota, to characterize hydrogeologic conditions at the crossing site. FERC included Environmental Condition 16 of the Certificate in response to concerns raised by the Minnesota Department of Natural Resources (MDNR) and the Minnesota Pollution Control Agency (MPCA) that the horizontal directional drill (HDD) crossing of Felton Creek may affect the hydrogeologic conditions in this area in such a way that groundwater discharge to calcareous fens located approximately 3.6 miles from the Felton Creek crossing would be reduced (FERC February 15, 2018 Order, Section IV.C.3.a., Para. 34, 35, and 36, pp ). Calcareous fens are regulated as Outstanding Resource Value Waters recognized by the MDNR and MPCA. Calcareous fens may not be drained or filled or otherwise altered or degraded except as provided for in a management plan approved by the commissioner of the MDNR. Agency concerns are that the HDD at Felton Creek, as planned, may intersect sand and gravel aquifers that could underlie fine-textured surficial sediments, resulting in a new discharge of groundwater and a corresponding reduction in the groundwater discharge in nearby fens. The geotechnical information provided below confirms that the HDD as planned remains in fine textured lacustrine sediments and avoids any impact on underlying sand and gravel aquifers. The Felton Creek crossing is located in Flowing Township (Township 141N, Range 46W, Sections 8 and 9), Clay County, Minnesota, approximately one mile west of Minnesota State Highway 9 and 0.5 mile south of Clay County Road 108 (140 th Avenue North). The HDD entry is on the east side of the stream at an elevation of approximately 912 feet. Along the profile of the HDD, the bore path crosses beneath the channelized portion of Felton Creek at a maximum depth of 20 feet below ground surface. The HDD exit is on the west side of the stream at an elevation of approximately 912 feet. Felton Creek flows southeast to northwest. The area is generally level, with the exception of the channelized ditch. 1.1 GEOLOGY Geology in the area of the Felton Creek crossing is mapped as the Sherack Formation, which is a deepwater sedimentary deposit from Glacial Lake Agassiz at the end of the Wisconsinan glaciation (Bauer, 2014). The fine-grained lake sediments in this formation consist mostly of calcareous clay, silty clay, and silt. It is mostly massive, but laminated in places, especially in upper portions of the formation. There is evidence of channel scour from erosion during periods of overland flow (Lusardi, et. al., 2005). The Project s crossing of Felton Creek is located within the lake basin, approximately 3.6 miles west of the western-most shoreline beach ridge, where calcareous fens have been identified. 1.2 HYDROGEOLOGY Groundwater in the area of the Felton Creek crossing occurs within both fine- and coarse-grained deposits; however, aquifers are limited to areas of sand and gravel. Regional hydrogeologic assessments estimate groundwater in the vicinity of the Felton Creek crossing at an elevation of 900 feet above mean sea level, or approximately 12 feet below grade (Trojan, 1997). Geologic mapping indicates fine-grained lake sediments are present in the area of the crossing and are inadequate for domestic water supplies (Bauer, 2014; Trojan, 1997). Geologic logs from water wells within one mile of the Felton Creek crossing indicate the fine-grained sediments in the area of the crossing are approximately 100 feet thick (MDH, 2018). 1

7 1.3 HYDROGEOLOGIC INVESTIGATION Three soil borings were completed on April 17, 2018 at the Felton Creek crossing by a drilling contractor, Dakota Technologies, Inc., under the direction of a Merjent Geologist. Soil borings were completed with a track-mounted GeoProbe hydraulic drilling rig using dual-tube methodology. Soil Borings W-1 and W- 2 were located approximately 183 feet and 91 feet west, respectively, of the HDD entry on the east side of Felton Creek (refer to Figure 1). Soil Boring W-3 was located approximately 90 feet east of the HDD exit point on the west side of Felton Creek. All soil borings were offset from the proposed centerline to avoid potential short circuiting and frac-out concerns. Soil boring logs for each soil boring are included in Appendix A. In general, the subsurface profile at the Felton Creek crossing, as observed in the borings, is described as follows: 4.5 to 8 feet of silty clay; 1 to 5.5 feet of silt with some sand that is interpreted as lake sediment; and up to 14 feet of fat clay, occasionally laminated with silt partitions that is also interpreted as lake sediment. Final depth of each soil boring was 20 feet below ground surface. Soil saturation was observed at a depth of approximately 12 feet in each soil boring. Temporary piezometers were installed at each soil boring location in a nested pair. A new borehole was drilled for the shallow piezometer set at each soil boring location (W-1A, W-2A, and W-3A) and screened at a depth between 10 and 15 feet to intersect the saturated zone identified in the soil borings. The original soil boring was used for the deep piezometer (W-1B, W-2B, W-3B) set at the base of each boring with a 1.0- to 1.5-foot long screen. Sand pack was installed around each screen and a 1-foot thick seal of bentonite pellets was placed above each sand pack to isolate the screened interval and prevent vertical migration of groundwater. The top of each piezometer was surveyed with an autolevel transit, with an estimated base elevation of 912 feet used for ground surface. Data loggers were suspended in each soil boring and prepared to log temperature, pressure, and depth every five minutes. Manual water levels were obtained, data loggers were removed, and the temporary piezometers were abandoned by Dakota Technologies, Inc. on Friday, April 20, after approximately 72 hours, which is the maximum amount of time allowed by the Minnesota Department of Health Well Management Unit for installation of temporary piezometers without obtaining a monitor well permit. 2

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9 1.3.1 Observations and Analysis The final water levels collected by Dakota Technologies using a water level indicator meter by the data loggers on April 20 are presented in the table below. Piezometer ID Top of Casing Elevation (ft.) Table 1 Water Levels Recorded by Piezometers Screened Interval Elevation (ft.-ft.) Depth to Water (ft.) Water Table Elevation (ft.) W-1A W-1B W-2A Dry Dry W-2B W-3A W-3B Horizontal groundwater flow direction cannot be determined due to a W-2A being dry, despite saturated soil conditions observed within the screened interval. Data logger graphs for the two shallow piezometers that contained water are presented in Appendix B. The graphs indicate that water levels in the shallow piezometers stabilized in 40 to 50 hours. Deep piezometer water levels do not appear to have stabilized during the monitoring period and the final water levels obtained manually indicate that the water level is just below the set depth of the data loggers. The slow response of groundwater in the deep piezometers indicates that the fat clay at depth does not readily transmit water and does not have a significant hydraulic head. Because the two piezometer intervals are not in aquifers that readily transmit water and are not stabilized, accurate vertical hydraulic gradients cannot be calculated. Water levels in W-1A indicate that the water table at this location is under an artesian condition, considering saturated soil was encountered at a depth of approximately 12 feet below grade and the water table was recorded at approximately 8.2 feet below grade. However, the transmissivity of the formation is low due to the amount of time required for the water table to stabilize. The water levels in W-3A indicate that the water table at this location is under a very slight artesian condition considering saturated soil was encountered at a depth of approximately 12 feet below grade and water table was recorded at approximately 11.6 feet below grade. 1.4 CONCLUSIONS In conclusion, the data indicate that the plan and profile of the planned HDD crossing of Felton Creek remains within fine-textured lacustrine sediments and does not intersect any underlying sand and gravel aquifers that may have a direct or indirect connection to the aquifers supporting the calcareous fens. These data are consistent with geological mapping that indicates the presence of thick, relatively uniform, finetextured lacustrine deposits in the area of the planned HDD. The hydraulic head present in portions of the water table at the Felton Creek crossing are not consistent with strong groundwater recharge or discharge, but are consistent with uniform, fine textured sediments distant from sand and gravel aquifers with higher hydraulic heads and noticeable groundwater discharge. The clay sediments deposited in deep water during the existence of Lake Agassiz at the crossing location are not hydraulically connected to the sand deposited at the beach ridge, which is located over 3.0 miles from the crossing. The intersection of the water table, and the deeper clay deposits, by the HDD drilling process would not likely alter the hydrogeologic conditions that support the calcareous fens associated with the beach ridge. As described in the Environmental Assessment prepared by the FERC for the Project, one function of the drilling fluid used 4

10 during HDD operations is to form a thin layer of clay on the borehole wall, thereby sealing the borehole from the surrounding formation, allowing for drilling fluid to return to the drilling rig where it is reused in a continuous, circulating fashion during the drilling process. This function of sealing the borehole wall, which remains in place after construction, also inhibits groundwater movement into the borehole, thereby reducing effects on water table and potentially connected surface water features. 5

11 2.0 REFERENCES Bauer, Emily J C-29 Geologic Atlas pf Clay County, Minnesota [Part A]. Minnesota Geological Survey. Available online from the University of Minnesota Digital Conservancy. Lusardi, Barbara, Anderson, F., and Harris K Surficial Geology of the Fargo-Moorhead Area. Minnesota Geological Survey. Available online from the University of Minnesota Digital Conservancy. Minnesota Department of Health (MDH) Minnesota Well Index. Accessed online: Trojan, Michael D Surficial Hydrogeology; Regional Hydrogeologic Assessment Series, RHA-3, Part B, Plate 3 of 4. Available online: df. 6

12 Appendix A Soil Boring Logs

13 Project: Valley Expansion Felton Creek Date: April 17, 2018 Driller: Dakota Technologies Geologist: Bruce Galer Boring No: W-1 Time Start: 9:20 Time Finish: 9:40 Water Depth: Sample Recovered/ ID Driven Drilling Method: Geoprobe Sampling Method: Dual-tube Surface Conditions: Grass MERJENT, INC. SOIL BORING LOG USCS Depth LITHOLOGIC DESCRIPTION 1 36 /60 CL/OL Brownish Black (10YR 3/1) SILTY CLAY, frozen to 1.5 ; soft below 1.5, moist; Topsoil 1 2 CL Brownish Black (10YR 3/1) SILTY CLAY, with 10YR 5/1 (Brownish Gray) mottles, medium soft to stiff, medium plasticity, moist; Topsoil /60 ML Orange (2.5YR 7/4) SILT with some SAND, very fine-grained, poorly graded, low plasticity, soft, moist; Lake sediment CH Reddish Gray (2.5YR 6/1) FAT CLAY, very soft, high plasticity, moist, laminated; Lake sediment / ML Orange (2.5YR 6/6) SILT with some SAND; very fine-grained, poorly graded, soft, low plasticity, laminated; saturated at 12.0 ; Lake sediment 13 CH Reddish Gray 2.5YR 4/1 FAT CLAY; soft, high plasticity, saturated, not laminated; Lake sediment 4 30 / End of boring at 20 ; No refusal Shallow Piezometer Construction: Screen set from ; Sand pack to 9. Deep Piezometer Construction: Screen set from ; Sand pack to 16.

14 Project: Valley Expansion Felton Creek Date: April 17, 2018 Driller: Dakota Technologies Geologist: Bruce Galer Boring No: W-2 Time Start: 10:40 Time Finish: 10:55 Water Depth: Sample Recovered/ ID Driven Drilling Method: Geoprobe Sampling Method: Dual-tube Surface Conditions: Grass MERJENT, INC. SOIL BORING LOG USCS Depth LITHOLOGIC DESCRIPTION 1 36 /60 CL/OH Brownish Black (10YR 3/1) SILTY CLAY, frozen, moist; Topsoil 1 CL Reddish Gray (2.5YR 4/1) SILTY CLAY, medium soft, low plasticity; Topsoil 3 ML Dark Reddish Gray (2.5YR 3/1) SILT with some SAND, very fine-grained, medium soft, low plasticity, moist; Lake sediment 2 48 / /60 10 ML Grayish Red (2.5YR 6/2) SILT with some SAND; very fine-grained; medium soft, low plasticity, moist; Lake sediment 7 CH/ML Grayish Red (2.5YR 5/2) FAT CLAY, with thin layers of Light Reddish Gray (2.5YR 7/1) SILT laminations, soft, moist, Lake sediment 9 11 CH Dull Reddish Brown (2.5YR 5/3) FAT CLAY, soft, high plasticity, saturated at 12.0 ; Lake sediment 13 CH Reddish Gray (2.5YR 4/1) FAT CLAY; soft, high plasticity, saturated, not laminated, scattered gypsum crystals; Lake sediment 4 42 / End of boring at 20 ; No refusal Shallow Piezometer Construction: Screen set from ; Sand pack to 9. Deep Piezometer Construction: Screen set from ; Sand pack to 18.

15 Project: Valley Expansion Felton Creek Date: April 17, 2018 Driller: Dakota Technologies Geologist: Bruce Galer Boring No: W-3 Time Start: 2:00 PM Time Finish: 2:15 PM Water Depth: Sample Recovered/ ID Driven Drilling Method: Geoprobe Sampling Method: Dual-tube Surface Conditions: Grass MERJENT, INC. SOIL BORING LOG USCS Depth LITHOLOGIC DESCRIPTION 1 36 /60 CL/OH Brownish Black (10YR 3/1) SILTY CLAY, frozen to 2, moist; Spoil from Ditching/Topsoil / / CL Reddish Gray (2.5YR 4/1) SILTY CLAY, medium soft, low plasticity; Topsoil CH/ML Grayish Red (2.5YR 5/2) FAT CLAY, with thin layers of Light Reddish Gray (2.5YR 7/1) SILT partitions, soft, high plasticity, moist, saturated at 12, 9 laminated; Lake sediment /60 CH Reddish Gray 2.5YR 4/1 FAT CLAY; soft, high plasticity, saturated, not laminated; Lake sediment End of boring at 20 ; No refusal Shallow Piezometer Construction: Screen set from ; Sand pack to 9 Deep Piezometer Construction: Screen set from ; Sand pack to 18.

16 Appendix B Data Logger Graphs for Piezometers W-1A and W-3A

17 W 1A /17/2018 0:00 4/17/ :00 4/18/2018 0:00 4/18/ :00 4/19/2018 0:00 4/19/ :00 4/20/2018 0:00 4/20/ :00 4/21/2018 0:00

18 W 3A /17/2018 0:00 4/17/ :00 4/18/2018 0:00 4/18/ :00 4/19/2018 0:00 4/19/ :00 4/20/2018 0:00 4/20/ :00 4/21/2018 0:00