Loading...
HomeMy WebLinkAbout2011 Shine Facility - Wahl Extraction Area Groundwater Report 1101 South Fawcett Avenue, Suite 200 Tacoma, Washington 98402 253.383.4940 March 20, 2012 Miles Sand & Gravel Company PO Box 130 Auburn, Washington 98071 Attention: Mike Schuh Subject: Letter Report Current Groundwater, Surface Water and Precipitation Monitoring Data Shine Facility – Wahl Extraction Area Jefferson County, Washington File No. 1355-035-00 It is our understanding that the Washington Department of Natural Resources (DNR) is requiring Miles Sand & Gravel Company (Miles) to submit a Groundwater Study along with their request for a DNR Reclamation Permit #70-013024 at the Shine Facility – Wahl Extraction Area (WEA) located in Jefferson County, Washington. 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 WEA as of the last data download event 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 for Fred Hill Materials. GeoEngineers assumed the monitoring duties in November 2009 when 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 a pressure transducer and datalogger in MW-9, a monitoring well located in the southwest portion of the WEA. The automated equipment 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 | March 20, 2012 Page 2 File No. 1355-035-00 ■ A pressure transducer and datalogger was installed in the Shine Hub water-supply well in April 2007. The equipment malfunctioned in June 2010 and was replaced in September 2010 with new equipment from the same manufacturer. The automated equipment records the groundwater level on an hourly basis and the information is downloaded quarterly during a visual inspection of the site. With the exception of a few months in 2010, the monitoring equipment has provided reliable data. ■ In January 2010, additional monitoring wells (MW-5 and MW-8) were added by Miles to estimate a groundwater surface profile beneath the WEA. The installed equipment is of the same manufacturer as the equipment installed in MW-9 and the Shine Hub well. The automated equipment records groundwater levels on an hourly basis and the information is downloaded quarterly during a visual inspection of the site. The current monitoring equipment provides reliable data. 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 above and Station 1 below the confluence of the unnamed tributary. The stream stage height at each station is recorded on an hourly basis using automated equipment. 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 automated equipment. The stream flow is measured manually on a quarterly basis by wading the stream and measuring stream velocity. ■ The automated equipment previously installed at the surface water stations has been replaced at all four stations in 2011 and 2012 with more reliable dataloggers. 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. The weather station is still functional and provides reliable data. MONITORING DATA SUMMARY The monitoring data was last collected at the WEA on February 8, 2012. GeoEngineers has developed plots of the monitoring data described below. The water levels have been converted to water level elevations. The elevations of the groundwater monitoring points (rims of the well casings) have been surveyed to the National Geodetic Vertical Datum (NGVD) 1929 datum. At this time, mining has not yet commenced in the WEA but several years of background groundwater, surface water and precipitation data have been acquired. Groundwater Data Figure 2 shows a plot of the groundwater data for the WEA from four monitoring points. The Shine Hub water supply well is located near the current office buildings at the Shine Facility (Figure 1). Monitoring wells MW-5, MW-8 and MW-9 are located within the WEA. Miles Sand & Gravel Company | March 20, 2012 Page 3 File No. 1355-035-00 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 three monitoring wells described below that are located over a mile west of the Shine HUB well. Monitoring Wells MW-5, MW-8 and MW-9 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 2008/2009, there was below-normal precipitation that was indicated by a decline in water levels from between early 2008 and late 2009. It also appears that, depending on the recent precipitation rates in 2012, the winter of 2011/2012 could show the same pattern of declining water levels through the winter. The highest recorded groundwater elevations were 279.50, 275.12 and 278.88 feet NGVD for MW-5, MW-8 and MW-9, 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 mean sea level (MSL) 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 the faulty recording equipment. The equipment was replaced in 2012 with more a reliable dataloggers. Figure 3 also shows the streamflow rates that were measured by wading the stream and plotted on a logarithmic vertical scale. The highest recorded flow 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. 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. It appears that the plan does show 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. For example, the highest recorded groundwater elevation at MW-9 was Elevation 278.88 feet and the proposed excavation there is Elevation 290 feet. Miles proposes to excavate to Elevation 275 feet in the southernmost extent of the WEA. Although there is a lack of groundwater monitoring data points in this area, it is our opinion that Elevation 275 feet is a reasonable depth based on additional data gathered by Fred Hill Materials (FHM) at MW-15, located Miles Sand & Gravel Company | March 20, 2012 Page 4 File No. 1355-035-00 approximately 500 feet south of the southern WEA mining disturbance boundary (Figure 1). The high water level recorded at MW-15 was reported by FHM to be 50 feet below ground, or Elevation 254 feet. Based on a uniform gradient between MW-9 and MW-15, the high groundwater elevation would be approximately Elevation 259 feet at the southern mining disturbance boundary and approximately Elevation 264 feet at the northern extent of the 275-foot excavation elevation contour 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 Sand & Gravel Co. at the Wahl Extraction Area are 10 feet or greater above the highest projected groundwater surface elevations. Please contact us if you have any questions about the water monitoring program. Sincerely, GeoEngineers, Inc. Joel W. Purdy, LG, LHG Senior Hydrogeologist Michael A.P. Kenrick, PE, LHG Principal Hydrogeologist JWP:MAPK:lc Copyright© 2012 by GeoEngineers, Inc. All rights reserved. Attachments: Figure 1. Vicinity Map Figure 2. Groundwater Data Figure 3. Surface Water Data Figure4. Precipitation Data Attachment 1. Wahl Reclamation Map Disclaimer: Any electronic form, facsimile or hard copy of the original document (email, text, table, and/or figure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. &( 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 Area Miles Sand & Gravel Company Shine, 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 1983 North 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 1 Station 3Station 2 Station 4 Legend @A Monitoring Well ED Stream Gage &(Shine Hub Weather Station Wahl Extraction Area MW-5 Station 1 T h o m d y k e C r e e k Creek