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HomeMy WebLinkAbout2018 Wahl Extraction Area Groundwater Monitoring Report 1101 South Fawcett Avenue, Suite 200 Tacoma, Washington 98402 253.383.4940 February 12, 2021 Miles Sand & Gravel Company 400 Valley Avenue NE Puyallup, Washington 98372 Attention: Ryan Ransavage Subject: Letter Report 2018 Groundwater, Surface Water and Precipitation Monitoring Data Shine Facility – Wahl Extraction Area Jefferson County, Washington File No. 1355-035-05 Monitoring requirements at the Shine Facility 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) through December 31, 2018 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 & Gravel Company (Miles) commenced leasing the operations at the WEA. The current monitoring program includes groundwater, surface water, and precipitation data acquisition. The monitoring locations are shown on Figure 1. Groundwater and surface water data are presented on Figures 2 and 3, respectively. Precipitation data are shown on Figure 3. 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 monitoring well MW-9, a monitoring well located in the southwest portion of the WEA (Figure 1). The transducer measures and records the groundwater level on an hourly basis and the information is downloaded quarterly during a visual inspection of the site. The transducer provided reliable data from August 2005 through November 2016. Miles Sand & Gravel Company | February 12, 2021 Page 2 File No. 1355-035-05 ■ By late 2016, excavation had progressed to the area surrounding monitoring well MW-9 and the wellhead was nearly inaccessible. The transducer in monitoring well MW-9 was removed on November 7, 2016. Monitoring well MW-9 was not accessible during 2017 and 2018. The casing for monitoring well MW-9 will be modified, and the transducer will be reinstalled after excavation and reclamation activities are complete in the area surrounding monitoring well MW-9. ■ A transducer was installed in the Shine Hub water supply well (Figure 1) in April 2007. The transducer malfunctioned in June 2010 and was replaced in September 2010 with new equipment from the same manufacturer. The transducer malfunctioned again in April 2013 and was repaired and reinstalled in July 2013. The transducer also temporarily stopped recording between March and May 2018. With the exception of a few months in 2010, 2013 and in 2018, the monitoring equipment has provided reliable data. ■ In January 2010, Miles installed additional transducers in monitoring wells MW-5 and MW-8 (Figure 1) to estimate a groundwater surface profile beneath the WEA. The installed transducers were from the same manufacturer as those installed in monitoring well MW-9 and the Shine Hub water supply well. The monitoring equipment installed in monitoring well MW-5 provided reliable data through April 2012. The monitoring equipment installed in monitoring well MW-8 provided reliable data through mid-March 2018. ■ In 2012, monitoring well MW-5 was deepened to explore for a groundwater supply for the facility. The exploration was unsuccessful, and MW-5 was decommissioned. Thus, the transducer from MW-5 was moved to monitoring well MW-15 (Figure 1) on May 2, 2012. Monitoring well MW-15 is located approximately 550 feet south of the proposed mining area and provides a monitoring point for the southern portion of the WEA. ■ The vented transducer in MW-8 was replaced in October 2015 with a new non-vented transducer (INW PT2X 50-psi). ■ By early 2018, excavation had progressed to the area surrounding monitoring well MW-8 and the wellhead was nearly inaccessible. The transducer in monitoring well MW-8 was removed on March 16, 2018. Monitoring well MW-8 was not accessible throughout the remainder of 2018. The casing for monitoring well MW-8 will be modified, and the transducer will be reinstalled after excavation and reclamation activities are complete in the area surrounding monitoring well MW-8. ■ The transducer removed from monitoring well MW-8 was installed in monitoring well MW-16, located approximately 1,430 feet northeast of monitoring well MW-8 (Figure 1). The transducer malfunctioned and was deemed inoperable; thus, a new non-vented transducer from the same manufacturer (INW LevelScout 30-psi) was installed on September 21, 2018. No survey elevation is available for the wellhead at monitoring well MW-16; thus, groundwater elevations have not been established at this monitoring location. We will continue to measure water levels at MW-16. Once the wellhead is surveyed, measured groundwater levels will be converted to elevations and plotted on Figure 2. Surface Water ■ Three surface water stations (Stations 1 through 3) were established in September 2005 on Thorndyke Creek near the WEA (Figure 1). 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 water-level sensor. The streamflow is measured manually on a quarterly basis by wading the stream and measuring stream velocity. Miles Sand & Gravel Company | February 12, 2021 Page 3 File No. 1355-035-05 ■ An additional surface water monitoring point (Station 4) is located on Thorndyke Creek approximately 1 mile upstream of its mouth (Figure 1). The stream stage height is recorded on an hourly basis using an automated water-level sensor. 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 was replaced at all four stations in 2011 and 2012 with more reliable sensors. The sensor installed at Station 4 malfunctioned in April 2014 and was repaired and reinstalled in June 2014. ■ The stream channel at Station 1 experienced significant channel migration beginning in early 2016. A large precipitation event in January 2016 moved the channel westward and away from the staff gage, leaving the staff gage out of the channel. The stream occupied this relocated channel through 2017 and 2018; thus, staff gage readings at Station 1 are not representative of actual surface water levels starting in January 2016. ■ In spring 2017, the stream channel at Station 3 bifurcated, and the staff gage was positioned at the edge of a center bar of the stream. Throughout most of 2018, the staff gage was several feet west of the wetted channel; thus, staff gage readings at Station 3 are not representative of actual surface water levels starting in spring 2017. ■ The stream channel and staff gage at Station 2 were affected by a small log jam sometime between the winter and spring 2017 monitoring events. The logs damaged the staff gage tape and caused a slight tilt to the staff gage. The logs were removed during the spring monitoring event to prevent further damage to the staff gage and the gage tape was replaced. ■ The stream channel at Station 4 bifurcated in early 2017, resulting in the formation of a gravel bar in the middle of the stream and deepening of the channel at the staff gage location. The condition of the staff gage was checked during each of the 2018 monitoring events. No modifications to the gage have been needed. ■ In January 2017, communication could not be established with the transducer installed at Station 3. The transducer was removed, sent in for repair, and reinstalled in June 2017. ■ In May 2017, the transducer at Station 2 malfunctioned and was removed, sent in for repair, and reinstalled in June 2017 but was subsequently moved to Station 1 by Miles and the Station 2 transducer was replaced with a new transducer in July 2017. ■ In October 2017, the transducer at Station 1 malfunctioned and was removed and sent in for repair. It was reinstalled in November 2017. ■ New staff gage tapes were installed at Station 1, Station 2, and Station 4 in July 2017. ■ Miles installed new non-vented transducers (INW LevelScout 30-psi) at all four stations on September 21, 2018. 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. Periodic data losses from September 1, 2013 through December 31, 2016 have occurred as a result of damage caused by power outages at the site. Therefore, the data for 2013 through 2016 is Miles Sand & Gravel Company | February 12, 2021 Page 4 File No. 1355-035-05 incomplete. A comparable dataset was acquired for January 1, 2012 through December 31, 2018 from the Kitsap Public Utility District No. 1’s (KPUD) rain gage at Edgewater, located on the Kitsap Peninsula approximately 5 miles southeast of the WEA. MONITORING DATA SUMMARY 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. Groundwater Data The elevations of groundwater monitoring points (rims of the well casings) MW-5, MW-8, MW-9, MW-15, and the Shine Hub water supply well 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 using surveyed monitoring point elevations. The elevation of groundwater monitoring point MW-16 has not been surveyed; thus, groundwater elevations have not been established at this location. A plot of groundwater elevations from monitoring wells MW-5, MW-8, MW-9, MW-15, and the Shine Hub water supply well is presented on Figure 2. The water supply well is located near the office buildings at the Shine Facility (Figure 1). Monitoring wells MW-5, MW-8, MW-9, and MW-16 are located within the WEA; monitoring well MW-15 is located approximately 550 feet south of the WEA (Figure 1). 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 (i.e., static) 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. Seasonal water level fluctuations in the Shine Hub water supply well are similar to the other site monitoring wells (described below), located over a mile west of the Shine Hub well, and are attributed to seasonal fluctuations in precipitation. Groundwater elevations observed at the Shine Hub water supply well showed relatively sharp increases in early 2016 and early 2017 (Figure 2). Groundwater elevations remained elevated through 2018 relative to pre-2016 groundwater elevations. A similar pattern was also observed in monitoring wells MW-8 and MW-15. This overall rise in groundwater elevations is likely the result of recharge from increased precipitation between 2016 and 2017 (Figure 4). The effects of increased annual precipitation and large individual precipitation events are also shown in the surface water monitoring records (Figure 3). Groundwater elevations at the Shine Hub water supply well appear to have peaked in early 2018 and may now be returning to pre-2016 water level elevations, which is likely the result of decreased precipitation in 2018 compared to total rainfall in 2016 and 2017. Miles Sand & Gravel Company | February 12, 2021 Page 5 File No. 1355-035-05 Monitoring Wells MW-8, MW-9, MW-15, and MW-16 The groundwater elevations in all the monitoring wells show similar seasonal fluctuations of rising levels in the wet winter months and declining levels between spring and fall. The highest recorded groundwater elevation for monitoring well MW-8 was 282.2 feet (NGVD 29) recorded in May 2017. Monitoring at well MW-8 was discontinued in March 2018 because excavation surrounding the well rendered the wellhead inaccessible. The dataset with the longest period of record is for monitoring well MW-9, beginning in August 2005 through November 2016. The highest recorded groundwater elevation for monitoring well MW-9 was 281.5 recorded in April 2016. The highest recorded groundwater elevation for monitoring well MW-15 was 256.8 feet recorded in May 2017. No survey elevation is available for the wellhead at monitoring well MW-16; thus, groundwater elevations have not been established at this monitoring location. We will continue to measure water levels at MW-16. Once the wellhead is surveyed, measured groundwater levels will be converted to elevations and plotted on Figure 2. As discussed above, the observed trend of rising groundwater elevations starting in 2016 at MW-8 and MW-15 is likely attributed to increased precipitation during the winters of 2016 and 2017. Groundwater elevations at MW-15 appear to have peaked in early 2017 and may now be returning to pre-2016 water level elevations, which is likely the result of decreased precipitation in 2018 compared to total rainfall in 2016 and 2017. Surface Water Data Figure 3 shows a plot of the surface water data for Stations 1 through 4, located on Thorndyke Creek and one of its tributaries. Figure 3 shows the stage heights as recorded on a 30-minute interval using dataloggers. The stage height dataset has had relatively short periods when the data was lost due to faulty monitoring sensors. In each case, the equipment was repaired or replaced. Figure 3 also shows the streamflow rates calculated from flow velocities that were measured by wading the stream; these rates are plotted on a logarithmic vertical scale (right-hand axis). Station 1 The highest measured flow at Station 1, located near the WEA (Figure 1), in 2018 was 13.2 cubic feet per second (cfs) during the March monitoring event and the lowest measured flow was 2.2 cfs during the August monitoring event. The stream channel at Station 1 experienced significant channel migration beginning in early 2016. Figure 3 shows a drop in recorded water levels following a large precipitation event in January 2016, which moved the channel westward and away from the staff gage, leaving the staff gage out of the channel. The stream occupied this relocated channel through 2017 and 2018; thus, staff gage readings at Station 1 (Figure 3) are not representative of actual surface water levels starting in January 2016. Station 2 The highest measured flow at Station 2 (Figure 1) in 2018 was 6.0 cfs during the March monitoring event and the lowest measured flow was 0.10 cfs during the October monitoring event. The stream channel position at Station 2 has meandered somewhat since at least 2010. As shown on Figure 3, measured surface water levels have dropped below the staff gage datum at times between 2010 and 2018 when the staff gage was near the bank or out of the channel. Station 3 The highest measured flow at Station 3 (Figure 1) in 2018 was 3.3 cfs during the March and April monitoring events and the lowest measured flow was 0.31 cfs during the October monitoring event. The stream Miles Sand & Gravel Company | February 12, 2021 Page 6 File No. 1355-035-05 channel at Station 3 migrated westward beginning in late 2016. In spring 2017, the stream channel bifurcated, and the staff gage was positioned at the edge of a center bar of the stream. Throughout most of 2018, the staff gage was several feet west of the wetted channel; thus, staff gage readings at Station 3 (Figure 3) are not representative of actual surface water levels starting in spring 2017. Station 4 The highest measured flow at Station 4 (Figure 1) in 2018 was 25.4 cfs during the March monitoring event and the lowest measured flow was 2.4 cfs during the October monitoring event. The stream channel at Station 4 bifurcated in early 2017 resulting in the formation of a gravel bar in the center of the stream. Flow diverted around the gravel bar appears to be incising the channel at the location of the Station 4 staff gage. Significant channel migration was observed upstream of Station 4 that may have resulted from multiple fallen trees impacting stream flow. Based on observations made during monitoring events conducted in 2017 and 2018, the channel at this location appears to be migrating westward. Precipitation Data Figure 4 shows a plot of the daily precipitation recorded at the weather station located on the roof of the Shine Hub office (2005 through 2016) and the KPUD’s Edgewater station (2009 through 2020). As stated above, it appears from the downloaded data that the Shine Hub weather station has had periods of malfunction and data loss since 2012. The weather station has not been collecting any precipitation data since early 2017. The Shine weather station data for 2012 through 2018 (Figure 4) is supplemented by data from the KPUD Edgewater Station rain gage until the Shine Hub weather station can be repaired. Comparing days when both stations recorded data, it appears that there has been significantly more rainfall at the Edgewater gage than recorded at the Shine weather station. The highest recorded daily precipitation event was 3.71 inches on January 21, 2016. The highest recorded daily precipitation event for 2018 was 1.77 inches on November 26, 2018. 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-8, located within the WEA, and MW-15, located approximately 550 feet south of the southern WEA mining disturbance boundary (Figure 1), indicates that the highest water levels recorded at MW-8 and MW-15 were Elevation 282.2 feet and 256.8 feet, respectively, in May 2017. The highest groundwater elevation recorded at MW-15 in 2018 was Elevation 256.5 in May 2018, which is approximately 0.3 feet lower than the peak groundwater elevation recorded at the well. Based on a uniform gradient between MW-8 and MW-15, the highest groundwater elevation would be approximately Elevation 262 feet at the southern mining disturbance boundary (Attachment 1) based on historical peak groundwater elevations. Thus, the proposed excavation elevation of Elevation 275 feet will be greater than 10 feet above the highest groundwater table based on available data. Miles Sand & Gravel Company | February 12, 2021 Page 7 File No. 1355-035-05 CONCLUSIONS Monitoring data for groundwater, surface water, and precipitation at the WEA 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 historical groundwater elevation profile beneath the planned mining area. Based on the groundwater data collected to date and historical groundwater elevation trends, the gravel mine excavations proposed by Miles at the WEA will be 10 feet or greater above the highest projected groundwater surface elevations. RECOMMENDATIONS Based on the monitoring conducted in 2018, we have the following recommendations: ■ We recommend surveying the elevation of the wellhead at monitoring well MW-16 so groundwater levels can be translated to groundwater elevations. ■ We recommend repairing or replacing the on-site Shine weather station as soon as possible so that it records accurate precipitation data. ■ We recommend that the stream channels be observed to evaluate whether the surface water gage stations need to be repositioned or deepened to monitor stream gage heights effectively. Please contact us if you have any questions about the water monitoring program. Sincerely, GeoEngineers, Inc. Eric N. Knoedler, LG Hydrogeologist Bridget A. August, LG, LHG Galan W. McInelly, LG, LHG Senior Hydrogeologist Principal ENK:BAA:GWM:leh 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. Attachments: Figure 1. Vicinity Map Figure 2. Groundwater Data Figure 3. Surface Water Data Figure 4. Precipitation Data Attachment 1. Wahl Reclamation Map Thorndyke RdPeabodyWayS Poi nt RdThorndyke Rd10 4 Wahl Lake RdThorndyke RdGro ve s Way DickeyStShine HubWaterSupply Well MW-9 MW-5 MW-8 MW-15 MW-16 Shine HubWeatherStation Vicinity Map Figure 1 Shine Facility - Wahl Extraction AreaJefferson County, 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 M aps 2005 Not es:1. The locati ons of all features shown are approximate.2. This drawing is f or information purposes. It is intended to assist in showing featur es discussed in an attached document. GeoEngineers, Inc. cannot guarantee t he accuracy and content of electronic files. The master file i s stored by G eoEngineers, Inc. and will serve as the official record of thi s com municat ion.3. It i s unlawful to copy or reproduce all or any part thereof, whether for personal use or resale, without permission. Tra nsv erse Merc ator, State P lane South, North American Datum 19 83North arro w o riented to grid northOffice: TACOPath: P:\1\1355035\GIS\135503500_F1.mxdMap Revised: 16 March 2020 maugustStation 1 Station 2 Station 3 200 2000 Fee t Station 1Station 3Station 2 St ation 4 Legen d Monitoring We ll Stream Gag e Shine Hub We ath er Stati on Wa hl E xtra ct io n A rea MW-5 Station 1 Thomdyke Creek Creek 1355-035-05 Date Exported: 03/18/20Figure 2 Groundwater Data Shine Facility –Wahl Extraction Area Jefferson County, Washington 1355-035-05 Date Exported: 03/18/19Figure 3 Surface Water Data Shine Facility –Wahl Extraction Area Jefferson County, Washington Notes: 1.The stream channel at Station 1 bifurcated in Early 2017, forming two channels that resulted in a gravel bar forming where the staff gage is located. 2.The stream channel at Stations 1, 2, and 3 shifted such that the staff gage was located outside the wetted channel at various times; thus, the recorded staff gage readings are below the staff gage. Staff Gage Datum 1355-035-05 Date Exported: 03/18/20Figure 4 Precipitation Data Shine Facility –Wahl Extraction Area Jefferson County, Washington Notes: 1.The computer that automatically downloads weather data at the Shine weather station was damaged in a power outage. The damage has affected precipitation data since 2012. Daily rainfall data was acquired from Kitsap Public utilities District No. 1’s Edgewater Station gage, located approximately 5 miles to the southwest, for June 18, 2009 through December 31, 2018. ATTACHMENT 1 Wahl Reclamation Map