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HomeMy WebLinkAboutSUB201900176 Review Comments Groundwater Assessment 2019-03-07COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road, Room 227 Charlottesville, Virginia 22902-4596 Phone (434) 296-5832 Fax (434) 972-4126 Tier III GW report review Project: Property of Bella Signature Homes, LLC — Tier III GW Assessment Report Tier III preparer: Earnest W. Beasley IV, CPG, HydroGeo Environmental, LLC 418 E. Main St. Charlottesville, VA 22902 Owner or rep.l : Bryan Chambers, Chambers Land Surveying[chamberslandsurveving(a,yahoo.com ] 253 Willow Drive, Keswick, VA 22947 Owner or rep.2: Clint Shifflett, Timmons Group [clint.shifflett(&timmons.com] 680 Preston Ave., Suite 200, Charlottesville, VA 22903 Applicant: Luke Kitelinger, Bella Signature Homes, LLC [kitelingerlgyahoo.com] 1410 Rialto Street, Charlottesville, VA 22902 Plan received date: 31 Jan 2019 Date of comments: 7 Mar 2019 Reviewer: John Anderson Planning Reviewer: Paty Saternye Engineering review of Tier III GW Assessment report is complete. SUB2018-00177 1. Tier III Groundwater Assessment: Albemarle County Parcel #45-59M for Bella Signature Homes, LLC, dated 1/29/19, is comprehensive, but is not approved. 2. Findings detail efforts to obtain well data from VDH, but VDH, as of report date, has been non -responsive to FOIA request for detailed well and septic records for parcels located up to 1000-feet beyond the property lines (ref. ACDSM, Sec. 2.13. La. l.d.). Table 1 (p. 5, report), Summary of Available Well Records, indicates the average yield of seventeen (17) well records for wells located within a 0.5 mile radius of the property is 12.9 gpm. Sec. 7.0, Conclusions (p. 6, report) states, "VDH regulations require a minimum yield of 3 gpm for private residential water supply wells, while Sec. 6.0, Assessment of Well Drilling and Testing, states, "Based on this study, the Site lies in an area capable of producing groundwater yield sufficient to meet the demands of the proposed Site development; however, the actual yields of future onsite supply wells cannot be known until the wells are drilled and properly tested." [Emphasis added.] 3. The only well listed in Table 1 located within one thousand feet of the parcel yields 2 gpm. The Tier III report states, "Standard practice for development of water supply wells involves drilling into water bearing zones in the fractured bedrock and sealing off the overburden with a solid well casing. Thus, the ultimate performance of individual water wells in the Blue Ridge Province typically depends on the borehole encountering sufficiently interconnected bedrock fractures. A dry hole results if a well is drilled into bedrock with insufficient fracturing. Fracture occurrence and density depend on a number of factors including specific location, rock type, and site -specific geologic conditions. Because groundwater occurs in discrete fractured zones, it is not unusual to find variability in yields for wells in close proximity to each other. Because the regolith provides groundwater storage, a thicker mantle of overburden usually suggests more favorable conditions for sustainable long-term groundwater withdrawals." (p. 3; emphasis added). 4. Attachment D, Water Budget Calculations for Tier III GW Assessment (Albemarle Co. Parcel #45-59M), rounding difference: If use .0015 feet vs .00147 as average regional daily groundwater recharge value, this Engineering Review Comments Page 2 of 2 increases the post -development groundwater surplus report value by a negligible amount (z2%). Attachment D projects 13,244 gpd surplus (post -development). For comparison, a household of five is estimated to consume 500 gpd, and the proposed five additional households in the watershed are included (subtracted) when calculating the 13,244 gpd surplus (if use .00147, surplus value decreases slightly to z12,851 gpd). Attachment D calculations may assume 1,000' x 20' principal access /road, may apportion 9,068 ft2 new impervious area per lot. Even allowing 100' x 12' stone or paved driveway allows 7,868 ft2 of impervious roof, walk, etc., per lot, which is conservative. Attachment D appears reasonable and accurate, and is accepted. 5. Report assessment of well drilling and testing, spatial variability of well yields, the relative lack of yield data within 1,000' radius of the parcel, requires test well results: a. Engineering recommends HydroGeo Environmental coordinate with Applicant, select a test drill location coincident with the proposed well site location evaluated (for reasons HydroGeo should outline for Engineering) to have low if not lowest potential well yield, and provide well test results in accord with VDH well test protocol. Should this test well yield at least 3 gpm, Engineering will approve the Tier III Groundwater Assessment. The only VDH available data within 1,000 of the parcel to be subdivided yields 2gpm, which is insufficient for VDH permitting purposes. Additional site -specific data is required to advance the final subdivision plat. b. Alternative to item 5.a.: If proposed location rated least likely to yield 3 gpm does not yield 3 gpm, Applicant should test a second of the five well sites for this 5-lot subdivision (ref. report /sketch — Attachment A), and may choose a proposed well site evaluated most favorable, perform well test, and average the two well test values. If this approach does not yield an average > 3 gpm, then Applicant may persuade Albemarle that each of the proposed subdivided lots has reasonable chance of encountering subsurface flow sufficient to support required 3 gpm, but this would seem doubtful. Water budget calculations have little to do with peril faced by property owners unable to establish a well supply that yields 3 gpm. Yields are influenced by chance, and additional site - specific information is required prior to Tier III GW Assessment Report approval. 6. Minor: Reduced -size plat /sketch scales are inaccurate. Include note that defines accurate scale, or revise plat sketches included with report using hand -notation to indicate an accurate scale so that a reader may refer to scale, and acquire accurate length or distance information from plats included with the report. Please call Engineering at 434.296-5832 -0069 if any questions. Thank you SUB201800177 Bella Signature GWA 030719