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Home My WebLink AboutSDP202000062 Assessment - Groundwater Minor Amendment 2020-12-11September 17, 2020 Mr. Jonathan Garber, P.E. (via email: jgarber@lineagearch.com) Principal Engineer Lineage Architects, P.C. 98 Lee Highway Verona, Virginia 24482 Subject: Tier III Groundwater Assessment — DS Tavern, Albemarle County Dear Mr. Garber, Candho Shaping the Future Cardno 10988 Richardson Road Ashland, VA 23005 USA Phone: 804 798 6525 www.cardno.com At the request of Lineage Architects, P.C. (Lineage), Cardno, Inc. (Cardno) has completed the following Tier 111 Groundwater Assessment for the DS Tavern site, located at 3449 Ivy Road, Charlottesville, Virginia. Site Description The property is located on the southwest side of Route 250 (Ivy Road), at approximately 38.0535220E, 78.567011°W (Figure 1). The property includes parcels 59-15A and 59-15A1, measuring approximately 1.8 acres and 0.9 acres, respectively, and currently consists of the historic DS Tavern, a small outbuilding, and a single -story house. Plans for the property consist of renovations and additions to be utilized as a small office and meeting space (Appendix A). Four (4) employees are expected to be present on the property fulltime, and will hold occasional meetings of up to thirty (30) people. The property is bounded on the northeast by Ivy Road, and adjoining properties on all other sides are residential and/or undeveloped, rural and wooded land. Properties to the northeast of Ivy Road are also rural and residential in nature. The property possesses gentle to moderate slopes. Elevation ranges from approximately 560 feet in the southwest portion of the site to approximately 520 feet on the northeastern boundary (Figure 1). Runoff from the property exits via an unnamed stream on the northeast boundary of the site that flows into Ivy Creek, approximately 0.75 miles north of the property. Ivy Creek is part of the Rivanna River Basin. Properties on the southwest side of Ivy Road in the vicinity of the DS Tavern are served by individual septic drainfields and private wells. Properties on the northeast side of Ivy Road are served by public water and individual septic drainfields. The DS Tavern site has an existing drainfield and well. 2 Geology and Soils According to the Geologic Map of Virginia (1993) produced by the United States Geologic Survey (USGS) and the Virginia Department of Mines, Minerals, and Energy (DMME), the entire site is underlain by porphyroblasic biotite- plagioclase augen gneiss (ybg). This gneiss is believed to be Paleoproterozoic to Mesoproterozoic in age (approximately 1 billion years), formed as a result of metamorphism of plutonic rock during the Grenville Crogeny. According to mapping conducted by the Natural Resources Conservation Service (NRCS), Hayesville Series loamy soils are predominant on the upland, southwestern portion of the property. The Hayesville loam is generally deep (approximately 1.5 to 2 meters deep) and well drained, formed by weathering of underlying meta -volcanic rock, which is consistent with the 1993 geologic mapping. Lowland soil on the remainder of the property is mapped as Colvard Series fine, sandy loam. The Colvard Series is generally 1 to 1.5 meters deep, well drained alluvium deposited in floodplains (note: property is located outside of FEMA 1 % and 0.2% flood hazard zones). Australia • Belgium • Canada • Colombia • Ecuador • Germany • Indonesia Kenya • New Zealand • Nigeria • Papua New Guinea • Peru • Philippines • Singapore United Arab Emirates • United Kingdom • United States • Operations in over 100 countries /+ �/ September 17, 2020 Ca/'[�/70.r Mr. Jonathan Garber, P.E. Shaping the Future Tier III Groundwater Assessment— DS Tavern Albemarle County 3 Existing Hydrogeologic Information Existing well records were reviewed using the Virginia Division of Geology and Mineral Resources (DGMR) GIS database. Reported yields for wells within 1,000 feet of the site and within the same geologic unit (ybg) ranged from 0 gallons per minute (gpm) to 12 gpm, with an average yield of 6 gpm. The total depths of these wells ranged from 160 feet to 508 feet, with an average depth of 315 feet. Additionally, a Freedom of Information Act (FOIA) request was made with Albemarle County Health Department, Office of Environmental Health for well records within 1000 feet of the site. The FOIA request did not reveal any wells on record. Finally, Cardno reviewed a copy of the Albemarle County Hydrogeological Assessment conducted in 2002. It was found that the site sits within Ragged Mountain Hydrogeological Unit where the average yield of wells was reported to be about 12 gpm. Shallow groundwater flow in the region is expected to approximately follow the surface topography (Figure 2). Based on this premise, the up -gradient watershed of approximately 40.3 acres was assumed to represent the groundwater recharge area from which the DS Tavern site would withdraw water. On average, approximately 46.8 inches per year of precipitation falls in Albemarle County, Virginia, of which 15.4 inches (33%) recharges groundwater (USGS SIR 2011-5198; Quantifying Components of the Hydrologic Cycle in Virginia using Chemical Hydrograph Separation and Multiple Regression Analysis). When applied to the 40.3 acre up -gradient watershed, this equates to an average groundwater recharge rate of 46,174 gallons per day (gpd), or 32 gpm. The area covered by impervious surfaces within this watershed is negligible, so was not subtracted from the total watershed area for this analysis. The only apparent groundwater discharge area for the property is the small, unnamed tributary to Ivy Creek that borders the northeast boundary of the property. 4 Potential and Known Contamination Sources In order to identify any potential sources of contamination, Cardno performed site reconnaissance, reviewed available Risks/Hazards Mapping from the Albemarle County GIS Website, and queried the Virginia Environmental Geographic Information Systems (VEGIS) operated by the Virginia Department of Environmental Quality (DEQ). VEGIS displays reports regarding petroleum release sites, Voluntary Remediation Program sites, Solid Waste Facilities and tank facilities. Two former petroleum Underground Storage Tanks (LISTS) of record were found to have existed (one of which is on the DS parcel). With the exception of the USTs, no environmental threats or environmental areas of concern (AOC) of record are present within 1000 feet of the site. DEQ has subsequently closed both the UST cases and are thus thought to represent low risks to environmental and human health. Five (5) parcels in the watershed up -gradient from the site have septic drainfields, all of which (including the site's drainfield, meet the Virginia Department of Health (VDH) stand-off requirements from wells; consequently, contamination from these drainfields is not expected. 5 Field Survey Summary Site and site vicinity reconnaissance was conducted on September 11, 2020. A windshield survey was conducted of the neighboring parcels in an effort to determine any visual signs of contaminant threats such as bury pits, petroleum tanks, etc. Additionally, Cardno was escorted through the site by Lineage Architect personnel where the well and drainfield location were identified. 6 Groundwater Management Plan This property will serve as a fulltime office space for four (4) employees, and on occasion, a meeting space for up to thirty (30) people. The US Office of Energy Efficiency and Renewable Energy's water use indices suggest a typical office requires approximately 15 gpd per employee. On a regular basis, this would require an average daily pumping rate of 0.042 gpm. On days when 30-person meetings are held, assuming the 30 people are present for www.cardno.com /+ �/ September 17, 2020 Ca/'[�/70. Mr. Jonathan Garber, P.E. Shaping the Future Tier III Groundwater Assessment— DS Tavern Albemarle County an entire day, the required average daily pumping rate would increase to 0.35 gpm. Assuming two (2) meetings per month, the required average daily pumping rate would be approximately 0.063 gpm. Existing groundwater use in the area is minor (rural residential, undeveloped) and the expected groundwater use at the DS Tavern site is only 0.2% of the estimated average annual groundwater recharge. Additionally, water usage by up -gradient groundwater users as well as the DS Tavern site is largely non -consumptive because septic drainfields are utilized for wastewater treatment. As such, groundwater quantity is not expected to be problematic. It is thought that the site is large enough to accommodate multiple well drilling locations if the existing well yield is insufficient. To ensure the longevity of the groundwater resource, Cardno recommends that development disturb as little of the site as practical and should consider measures to promote groundwater recharge (e.g., permeable pavement). Additionally, the pump in the existing well and in any future wells should be sized and operated in a manner to keep the major water -bearing fracture zones submerged. Future wells, if necessary, should also be located as far from neighboring wells as practical. 7 Conclusions It is Cardno's opinion that groundwater is available in sufficient quantity to support the proposed DS Tavern development without having an adverse impact on the ability of existing groundwater users to withdraw groundwater. Additionally, no existing or potential sources of contamination are expected to impact water quality at the site. Generally accepted industry standards were used in the preparation of this report. Stated opinions and conclusions are not intended as a guarantee. The only reliable way to confirm that a sustainable groundwater resource is present is to test a well for quantity and quality. Thank you for the opportunity to provide hydrogeological services to Lineage Architects. Please feel free to contact us with any questions. Sincerely, Vincent Day, P.G. Senior Hydrogeologist for Cardno Direct Line: +1 804 368 1003 Email: vincent.day@cardno.com Figures Figure 1 — Site Geology and Features Figure 2 — Recharge Area and Flow Direction Attachments Attachment 1 — C-03: Existing Conditions Attachment 2 — C-04: Overall Site Plan Attachment 3 — C-05: Grading / E&SC Plan Bryant Mountjoy, GIT Staff Hydrogeologist for Cardno Direct Line: +1 804 412 6546 Email: bryant.mountjoy@cardno.com www.cardno.com 1W 59-19 59-20 560 580 S20 S60 59-16A 59-17 [59- B" 59-15A i0 99-15A 1 59-15® \17B 59-15 5959-15C i o1-oe-s 59A-0B-10 1 59A-01-013-11 0 59-14A1 -OB-7A 59-24B 59-14A I '0 Wells Streams 59-80A _ Drainfields Elevation Contours (ft) 'Drainfields and Wells symbols represent o lots served by drainfields and/or wells, IDS Tavem Site - Biotite-gneiss it not precise locations O 1,000 Foot Radius - Orthogneiss ;� �C 0 Parcels � cdg o sri. DigitalGlobe. GeoEye, Earthstar Geographics�CNES/Airbus A. USGS. AeroGRID. IGN, and the GIS User`Confimunity DRAWN: BM CHECKED: VD DS TAVERN SITE FIGURE Cardnly DATE: 9/10I2020 0 150 300 ALBEMARLE COUNTY, VA SCALE: 1:9,900 PROJECT NO.: LA001 ® p 1 FILE NO.: SITE GEOLOGY OFFICE: ASHLAND AND FEATURES