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Home My WebLink About2014 Wahl Extraction Area Groundwater Monitoring Report 1101 South Fawcett Avenue, Suite 200 Tacoma, Washington 98402 253.383.4940 January 26, 2015 Miles Sand & Gravel Company P.O. Box 130 Auburn, Washington 98071 Attention: Mike Schuh Subject: Letter Report 2014 Groundwater, Surface Water and Precipitation Monitoring Data Shine Facility – Wahl Extraction Area Jefferson County, Washington File No. 1355-035-00 Monitoring requirements at the site were set forth by Jefferson County Department of Community Development (DCD) as conditions of the Wahl Permit (MLA03-0037), dated July 18, 2005, prepared originally for Fred Hill Materials (FHM) and Ordinance 08-0706-04 (MLA10-00073), Amendment 09-1213-10 dated December 18, 2010. The purpose of this letter is to provide a summary of the water monitoring program implemented for the Wahl Extraction Area (WEA) as of the last data download event on January 16, 2015 and to compare the high groundwater table elevations with the proposed excavation elevations at the WEA. PREVIOUS AND CURRENT MONITORING The original monitoring, initiated in August 2005, was conducted by CR Hydrogeologic Consulting FHM. GeoEngineers, Inc. (GeoEngineers) assumed the monitoring duties in November 2009 when Miles Sand and Gravel Company (Miles) commenced leasing the operations at the WEA. The monitoring locations are shown on Figure 1. The following are elements of the current monitoring program: Groundwater ■ Groundwater level monitoring at the WEA began in August 2005 with the installation of an automated water-level sensor (consisting of a combined pressure transducer and datalogger) in MW-9, a monitoring well located in the southwest portion of the WEA. The automated sensor measures and records the groundwater level on an hourly basis and the information is downloaded quarterly during a visual inspection of the site. The monitoring equipment is still functioning and has provided reliable data. Miles Sand & Gravel Company | January 26, 2014 Page 2 File No. 1355-035-00 ■ A water-level sensor was installed in the Shine Hub water supply well in April 2007. The sensor malfunctioned in June 2010 and was replaced in September 2010 with new equipment from the same manufacturer. The sensor malfunctioned again in April 2013 and was repaired and reinstalled in July 2013. With the exception of a few months in 2010 and in 2013, the monitoring equipment has provided reliable data. ■ In January 2010, additional monitoring wells (MW-5 and MW-8) equipped with sensors were added by Miles to estimate a groundwater surface profile beneath the WEA. The installed sensors are from the same manufacturer as those installed in MW-9 and the Shine Hub well. The current monitoring equipment provides reliable data. ■ In 2012, MW-5 was deepened to explore for a groundwater supply for the facility. The exploration was unsuccessful and MW-5 was decommissioned. Thus, the water level sensor from MW-5 was moved to MW-15 on February 15, 2012. MW-15 is located approximately 550 feet south of the proposed mining area and now provides a monitoring point for the southern portion of the WEA. Surface Water ■ Three surface water stations were established in September 2005 on Thorndyke Creek near the WEA. One of the stations (Station 3) is located on an unnamed tributary and two are located on Thorndyke Creek, with Station 2 upstream and Station 1 located downstream of the confluence with the unnamed tributary. The stream stage height at each station is recorded on an hourly basis using an automated sensor. The streamflow is measured manually on a quarterly basis by wading the stream and measuring stream velocity. ■ An additional surface water monitoring point (Station 4) is located on Thorndyke Creek approximately 1 mile upstream of its mouth. The stream stage height is recorded on an hourly basis using an automated sensor. The stream flow is measured manually on a quarterly basis by wading the stream and measuring stream velocity. The sensor installed at Station 4 malfunctioned in April 2014 and was repaired and reinstalled in June 2014. ■ The automated equipment previously installed at the surface water stations was replaced at all four stations in 2011 and 2012 with more reliable sensors. Precipitation ■ A weather station was established on the roof of the office building at the current Shine Hub in September 2005. The data, collected on an hourly basis, includes precipitation, temperature and wind direction and speed. Between March 14 and October 17, 2012, the weather station experienced a loss of data. Miles has reportedly implemented periodic data downloads to minimize potential future loss of data. As of October 17, 2012, the weather station is functional and once again is providing reliable data. MONITORING DATA SUMMARY The latest set of monitoring data was collected at the WEA on January 16, 2015. GeoEngineers has developed plots of the monitoring data described below. Mining has commenced in the WEA and several years of background groundwater, surface water and precipitation data have now been acquired. Miles Sand & Gravel Company | January 26, 2014 Page 3 File No. 1355-035-00 Groundwater Data The elevations of the groundwater monitoring points (rims of the well casings) have been surveyed relative to the National Geodetic Vertical Datum (NGVD) 1929 datum. The water levels measured in each monitoring well have been converted to groundwater elevations. Figure 2 shows a plot of groundwater elevations from the four monitoring wells and the Shine Hub water supply well. The water supply well is located near the office buildings at the Shine Facility (Figure 1). Monitoring wells MW-5, MW-8 and MW-9 are located within the WEA; monitoring wells MW-15 is located approximately 550 feet south of the WEA. Shine Hub Water Supply Well The hourly data from the Shine Hub water supply well are shown on Figure 2 as points because the well pump cycles on and off several times a day. The lowest water level elevations in the Shine HUB water supply well represent pumping water levels and the highest represent fully or nearly recovered water levels. The data in-between represent water levels that are either recovering or are being drawn down at various stages of the pumping cycle. The highest levels show a pattern similar to the other monitoring wells described below that are located over a mile west of the Shine Hub well. Monitoring Wells MW-5, MW-8, MW-9 and MW-15 The dataset with the longest period of record is for monitoring well MW-9, beginning in August 11, 2005. The groundwater elevations in all the wells show similar seasonal fluctuations of rising levels in the winter wet months and declining levels between spring and fall. During the winter of 2008-09, there was below-normal precipitation that was indicated by a decline in water levels from between early 2008 and late 2009. The highest recorded groundwater elevation of 282.50 feet (NGVD 29) for MW-5 was recorded in 2011. The highest recorded groundwater elevations for other observation wells were all recorded in 2013. These groundwater elevations were 278.38, 279.48 and 254.71 feet (NGVD 29) for MW-8, MW-9, and MW-15, respectively. Surface Water Data Figure 3 shows a plot of the surface water data for Station 1, located on Thorndyke Creek southwest of the southernmost extent of the WEA, as a typical example of the surface water datasets. An elevation of 233 feet NGVD is estimated at Station 1 based on the U.S. Geologic Survey topographic map. Figure 3 shows the stage heights as recorded at a 30-minute interval using dataloggers. The stage height dataset had three relatively short periods in 2010 and 2011 when the data was lost due to faulty monitoring sensors. The equipment was replaced in early 2012 with more reliable sensors and the stage heights were recorded at an hourly interval. Figure 3 also shows the streamflow rates calculated from flow velocities that were measured by wading the stream; these are plotted on a logarithmic vertical scale (right-hand axis). The highest recorded flow at Station 1 was 56.27 cubic feet per second on January 4, 2008. Precipitation Data Figure 4 shows a plot of the daily precipitation at the weather station located on the roof of the Shine Hub office. The highest recorded daily precipitation event was 3.11 inches on December 3, 2007. Miles Sand & Gravel Company | January 26, 2014 Page 4 File No. 1355-035-00 GROUNDWATER ELEVATIONS VERSUS PROPOSED EXCAVATION FLOOR The proposed excavation elevations are shown on the attached plan titled “WDNR Permit No. 70-013024 Final Reclamation Map” as prepared by Team 4 Engineering. The plan shows that the excavation will stay 10 feet above the high groundwater table, as a currently required condition, in the central and north portions of the WEA. Miles proposes to excavate to Elevation 275 feet in the southernmost extent of the WEA. Prior to 2012 there was a lack of groundwater monitoring data points in this area. Monitoring of MW-15, located approximately 550 feet south of the southern WEA mining disturbance boundary (Figure 1), indicates that the highest water level recorded at MW-15 was Elevation 254.71 feet. Based on a uniform gradient between MW-9 and MW-15, the high groundwater elevation would be approximately Elevation 261 feet at the southern mining disturbance boundary as shown on the Reclamation Map (Attachment 1). Thus, the proposed excavation elevation of Elevation 275 feet will be greater than 10 feet above the highest groundwater table based on available data. CONCLUSIONS Monitoring data for groundwater, surface water and precipitation at the Wahl Extraction Area are being collected by GeoEngineers on an ongoing basis to develop an extensive background data set, as required under permit conditions and local ordinances. Data have been collected since 2005, and additional groundwater monitoring locations installed in 2009 have allowed the estimation of a groundwater elevation profile beneath the planned mining area. Based on the groundwater data collected to date, the gravel mine excavations proposed by Miles at the Wahl Extraction Area are 10 feet or greater above the highest projected groundwater surface elevations. &( EDEDED ED @A @A @A @A @A Shine Hub Weather Station MW-15 MW-8 MW-5 MW-9 Shine Hub Water Supply WellWahl Lake Rd Thorndyke Rd UV104 Thorndyke Rd S Po in t Rd Peabody Way T h o r n d y k e R d µ Vicinity Map Figure 1 Shine Facility - Wahl Extraction AreaMiles Sand & Gravel CompanyShine, Washington !^ Olympia §¨¦90 §¨¦5 §¨¦405 £¤101 Olympic NP W a s h i n g t o n 3,000 3,0000 Feet Data Sources: ESRI Data & Maps, Street Maps 2005 Notes:1. The locations of all features shown are approximate.2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication.3. It is unlawful to copy or reproduce all or any part thereof, whether for personal use or resale, without permission. Transverse Mercator, State Plane South, North American Datum 1983North arrow oriented to grid northOffice: TACO Path: P:\1\1355035\GIS\135503500_F1.mxdMap Revised: 20 March 2012 syiEDED ED Station 1 Station 2 Station 3 200 2000 Feet Station 1Station 3Station 2 Station 4 Legend @A Monitoring Well ED Stream Gage &(Shine Hub Weather Station Wahl Extraction Area MW-5 Station 1 Tho m d y k e C r e e k Creek Groundwater DataShine Facility- Wahl Extraction AreaJefferson County, WashingtonFigure 2SP:\1\1355035\00\finals\Shine Facility –2014 Annual Report_Figures2 through 4.pptx JWP 01/21/2015 Surface Water DataShine Facility- Wahl Extraction AreaJefferson County, WashingtonFigure 3SP:\1\1355035\00\finals\Shine Facility –2014 Annual Report_Figures2 through 4.pptx JWP 01/21/20151/1/04 1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11 1/1/12 1/1/13 1/1/14Date012340.11101001000Station 1 Relative Stage HeightsWaded Stream Flow Measurements1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11 1/1/12 1/1/13 1/1/14 1/1/15Date012340.11101001000Station 4 Relative Stage HeightsWaded Stream Flow MeasurementsSensor Replaced5/6/111/1/04 1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11 1/1/12 1/1/13 1/1/14 1/1/15Date012340.11101001000Station 2 Relative Stage HeightsWaded Stream Flow MeasurementsRelocated Station 2approximately 300 feet upstreamon 2/15/2011Faulty ReadingsSensor Replaced2/3/121/1/04 1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11 1/1/12 1/1/13 1/1/14 1/1/15Date-1012340.11101001000Station 3 Relative Stage HeightsWaded Stream Flow MeasurementsStream Bed ErodedBelow Staff Gage DatumReplaced Sensor5/6/11 Precipitation Data Shine Hub Weather StationShine Facility- Wahl Extraction AreaJefferson County, WashingtonFigure 4SP:\1\1355035\00\finals\Shine Facility –2014 Annual Report_Figures2 through 4.pptx JWP 01/21/20151/1/04 1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11 1/1/12 1/1/13 1/1/14 1/1/15Date012345Daily Precipitation (inches) ATTACHMENT 1 Wahl Reclamation Map