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Home My WebLink AboutSP202100007 Floodplain Development Permit 2021-03-15rtin 1 i1tC:l:�« COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road Charlottesville, Virginia 22902-4596 Phone(434)296-5832 Fax(4341972-4126 FLOODPLAIN DEVELOPMENT PERMIT This form is intended to aid the Department in documenting and characterizing the nature of development proposed in the floodplain. Development includes buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations or storage of equipment or materials. The form responses will be used to determine whether a floodplain impact plan or special use permit is required. Please check one: ❑ New Submittal with no anticipated floodplain impact (no floodplain impact plan) ❑ New Submittal with an anticipated floodplain impact. Please include afloodplain impact plan. FEE required with submittal: $323 (Code 18-35.1g) ❑ FEMA Letter of Map Change (LOMA, LOMR) Please include a complete copy of all material to be submitted to FEMA. Include any computer models (HEC-RASfiles) on a disc. FEE required with submittal: $161 (topographic info only), or $323 (floodplain modeling) ❑ New Submittal with a Zoning Special Use Permit. Please include a floodplain impact plan. FEE required with submittal: $323 ❑ Resubmittal (Floodplain Development Permit Number ) Please include your response form from the original submittal. FEE as above required with each resubmittal. A Floodplain Impact Plan, Special Use Permit, or FEMA Map Change will need to follow Zoning Floodplain Overlay District requirements (County Code 18-30.3), found at httt)://www.albemarle.orgJut)load/imap-es/Fortns Center/Denartments/County Attomev/Forms/Albemarle Countv Code Chl8_Zoning30 Overlay Districts.pdf Section 4 of the Design Standards Manual provides a list of required items to be included in a Floodplain Impact Plan. This can be found at http://www.albemarle.org/departtnent.asp?department=cdd&relpage=4447. Let It Go, LLC 434-979-8900 Owner Name (Print) Home Phone Office / Other Phone 724 Jefferson Mill Lane Address Scottsville VA 24590 City State Zip Code Tax Map & Parcel Number Lot 123-26 Project Name (if applicable) Jefferson Mill hydroelectric Project Building Permit or Project Number (if applicable) r urrzoLs Please describe the nature of the development activity proposed within the floodplain (e.g. new structure, grading for a playing field, driveway stream crossing, installation of a fence, etc.): The project proposes to rehabilitate the existing powerhouse with a new turbine and generator. An intake structure that will divert 20 cfs to 45 cfs (cubic feet per second) of river flow into a 3-ft diameter penstock. After passing through the turbine, the water will return to the river, just downstream of the dam. The elevation of the dam crest will not change, nor will the dam's impoundment area. There will be no net increase in fill in the floodplain. (Please attach any plans or photos to this application) 1. If a structure is proposed, is the structure accessory to a recreational or agricultural use? Yes No N/A 2. Does the proposed activity involve a stream crossing for a pedestrian trail or driveway serving a single family dwelling? Yes No N/A 3. Does any proposed fencing cross a stream channel? Yes No N/A 4. If any fill is proposed, please approximate the proposed amount of fill in the floodplain Owner / Agent Signature `a-,4 "21 i4 -- - Date 3/2/2021 Natel Energy signing as agent for Let It Go, LLC (FOR OFFICE USE ONLY) Checked By Date (for resubmittals) Fee Amount $ Date Paid By Who? Receipt # Check # it/l/2015 Albemarle County Floodplain Development Permit No.: ENGINEERING "NO -RISE" CERTIFICATION Community: Scottsville County: Albemarle Applicant: Let It Go, LLC Date: 03-02-2021 Address: 724 Jefferson Mill Lane Telephone: 434-979-8900 Engineer: David A. Krisnitski, PE VA Address: 1734 Seibel Drive, N.E., Roanoke, VA 24012 540.344.7939 SITE DATA 1. Location: NA /4; NA /4; Section NA ; Township NA ; Range NA Street Address: 724 Jefferson Mill Lane, Scottsville, VA 24590 2. Panel(s) No. of NFIP map(s) affected: Lot 123-26 Deed Book/Page = 3340/466 3. Type of Development: Filling Grading ❑ Excavation Q Minor Improv. 0 Substantial Improv. ❑ New Construction ❑ Other ❑ 4. Description of Development: The project proposes to rehabilitate the existing powerhouse with a new turbine and generator. An intake structure will be excavated into the riverbank, within the 100 year flood zone. Water will flow through a penstock into the powerhouse, pass through the turbine, and return to the river just downstream of the dam. 5. Name of Flooding Source: Hardware River COMMENTS: The intake structure will be built mostly below the existing grade with only a small portion of the structure extending above the current ground elevation. The reduction in flow area due to the proposed structure is 10.8 square feet that will be placed within the floodplain. Additionally the flow area at this cross section will be increased by a minimum of 11.7 s.f. that will be removed from the riverbank providing a net increase in the available flow area. The result is no net increase in fill placed within the floodplain. This is to certify that I am a duly qualified engineer licensed to practice in the State of Virginia. It is to further certify that the proposed development as described in the Jefferson Mill Dam Design dated March 2021, has an area of less than 5 acres and that construction of the proposed design will not result in an increase in flood elevations for any adjacent property owners along the Hardware River. This conclusion is based on the geometry of the proposed intake strucct site grading. Xt a t,Tak Name: David A. <risnitski r Signature:'Oel Date: 3/11/2021 Title: Water Resource Engineer License No.: R7-No Rise (Converted to Adobe Form by State of Virginia) JEFFERSON INTAKE NO RISE CALCULATION FILL=10.8SF CUT=11.7SF STRUCTURE WIDTH = 12 FT FILL=130CF CUT=140CF PVC ENCASED IN CONCRETE FOR STEM (LOCATION AND 325 SIZE TO BE COORDINATED WITH SLUICE GATE SUPPLIER) GROUNDSURFACE TOP OF WALL ELEV. 32Z3 ------ 7 ELEV. 323.0 / 36" DIP PENSTOCK CONDUIT P-7CONCRETE CRADLE SLUICE GATE OPERATOR SLUICEGATE CLOF PENSTOCK \ ELEV. 315.5 \bs -#5 REBAR@ e•Y'� '1 8" SPA (TYP) NORMAL POOL/ TOP OF DAM ELEV. 319.7 TRASH RACK ASSUME ROCK RIVERBED ,1SECTION - PENSTOCK INLET STRUCTURE p \1J/ Lat = 37.8413 Long =-78.4746 71 j 0% ", -- � ti7 National Flood Hazard Layer FIRMette 3, FEMA 0 250 500 1,000 1,500 2,000 Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020 Legend SUMS REPORT FOR DETAILED LEOENDAND INM MAR MR FIRM PANEL LAYOUT Without Base Flood Elevation (BFE) Zone A. V. A99 SPECIAL FLOOD With BFE or Depth zone AE, Ao, AR, W, AR HAZARD AREAS Regulatory Floodway OTHER AREAS OF FLOOD HAZARD 0.2%Annual Chance Flood Hazard, Areas of 1%annual chance flood with average depth less than one font or with drainage areas of less than one square mile zone x Future Conditions 1%Annual Chance Flood hazard zneex Area with Reduced Flood Risk due to Levee. See Notes. zoncx Area with Flood Risk due to Leveezone D NOSCREEN Area of Minimal Flood Hazard zonex Q Effective LOMRs OTHER AREAS Area of Undetermined Flood Hazard zoom D GENERAL ---- Channel. Culvert, or Storm Sewer STRUCTURES 11111 I I Levee, Dike, or Floodweill e 2aa Cross Sections with 1%Annual Chance tvs Water Surface Elevation v- - - Coastal Transact ---r°--- Base Flood Elevation Line (BFE) Limit of Study >` Jurisdiction Boundary - — --- Coastal Transact Baseline OTHER - Profile Baseline FEATURES Hydrographic Feature Digital Data Available N No Digital Data Available MAP PANELS Unmapped 4 The pin displayed on the map Is an approximate point selected by the user and does not represent an authoritative property location. This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by REM A. This map was exported on 3/2/2021 at 4:02 PM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded oy new data over time. This map image is void if the one or more of the following map elements do not appear: basemap Imagery, flood zone labels, legend, scale bar, map creation date, community Identifiers, FIRM panel number, and FIRM effective date. Map Images for unmapped and unmodernized areas cannot be used for regulatory purposes. ¥¥! ƒ2� �¢� |. ! ;. \ mlGg§ : a :•): \PHI @@ FOR GA (LOCATION 325 SIZE TO BE PLEFOREAS NAUR — AUNC,tienlGROUND BE - E. "IF � \ v Q FmV POP " NEW 330 360P[ xoms� BEFERECI \�SuoLEosRlw ¢ laewre SEE D BE • 335 —CRADLE _ RED rn lTr% aq i EXPEARATE INTAKE 310 /2 SECTION - PENSIE IXINI S UCRIRE U GOVERNING WITH GRIP GROOVE — - L DECK STAB UPSTREAM CONCRETE NEW CONCRETE LINER CLOSURE WALL mpBO••OVRET OVERHANG WALL(MIN fi"THICK) PIPE NATELENENESTRUS HERE p5 RERET 0 B°O.C. .Y WITH ORIP PIPE SUPPORT STAND WITI DRAFT TUBE (IMPVERT6 HOPED GRODVE WWF BAR GENEROUS pg"�pDI USEDBLE COUPLER RE MOVE EXISTING LUSTERLESS STONE WALL j 36"0 CLOT PIPE/5. RUNE PENSTOR fi OB'O9]°ELBOW AT ELEV. 315.0 CONOUR 3.0 AD AD I `� �� _ __ _ EXiflA FUNGE 1 FOP CON[NkTE `. — � 1` ENGAGEMENT �� POTFNTTAL FIN WI BOON ROCKTO BE EXCAVATED +Ne., RED0FOROUTIETTOPOFE%ISTINGOUTIET (I% SCOPE TO SUMP( ECRO ROCKTO BE TXICRENEUSIABTOSUPPOPENING-ELEV. 311.0 A'd EO FOR OURET WY/F6MDlWDM TU RBINE AND HEADWALL 3°SUMP OVFIFF BECASTAROUNV EIOOW WITH CHECK VALVE J FORM AND POUR SIRVCTUHILCOHCRI EE.BEDWN SIMIN DOWNSTREAM END OF THE ELDOW 5O SEES TO I£V.3W. U PSTREAM ENO AUGURS AT BEEN. 315.O n TURBINE ROOM ELEVATION VIEW