PHILPOTT LAKE PROJECT PERTINENT DATA Location of dam On Smith River at latitude 36 46'50", longitude 80 01'40", about 44.3 river miles above the mouth, about 7 miles upstream from Bassett, Virginia, and 34 air miles south from Roanoke, Virginia. Drainage areas, square miles Smith River at Philpott Dam site . . . . . . . . . . . . 212 Smith River at Bassett, Virginia (gage). . . . . . . . . 253 Smith River at Martinsville, Virginia . . . . . . . . . 374 Smith River at mouth near Eden, N. C . . . . . . . . . . 550 Flows at damsite in period Sep 1929 - Dec 1981. c.f.s. Average . . . . . . . . . . . . . . . . . . . . . . . . 285 Maximum (19 Oct 1937) . . . . . . . . . . . . . . . . 32,000 Minimum (weekly mean, Sept 1932) . . . . . . . . . . . . 40 Maximum monthly (Oct 1937) . . . . . . . . . . . . . . .1,205 Minimum monthly (Aug 1981) . . . . . . . . . . . . . . . 29 Elevations, feet, mean sea level Top of dam . . . . . . . . . . . . . . . . . . . . . . .1,016 Flood plain (general elevation). . . . . . . . . . . . . 815 Base of dam (approx.). . . . . . . . . . . . . . . . . . 797 Crest of spillway. . . . . . . . . . . . . . . . . . . . 985 Maximum surcharge elevation (spillway design flood). . .1,014 Top of power intakes . . . . . . . . . . . . . . . . . . 902 Minimum elevation to which land has been purchased or flowage easement acquired . . . . . . . . . . . . . . . 998 Reservoir clearing limits: Upper. . . . . . . . . . . . . . . . . . . . . . . . 977 Lower. . . . . . . . . . . . . . . . . . . . . . . . 940 Max. (22June72) . . . . . . . . . . . . . . . . . . . 983.06 Min. (26Sep56). . . .. . . . . . . . . . . . . . . . . 927.59 Tailwater elevations. feet, mean sea level. Maximum level for spillway design flood outflow (70,000 c.f.s.) . . . . . . . . . . . . . . . . . . . . 836 Maximum design level for protection of powerhouse (20,000 c.f.s.) . . . . . . . . . . . . . . . . . . . . 822 Normal operating level . . . . . . . . . . . . . . . . . 811 Minimum level, regulated flow (20 c.f.s.). . . . . . . . 808 Reservoir State affected . . . . . . . . . . . . . . . . . . . . . Virginia Counties affected. . . . . . . . . . . . Franklin, Henry, Patrick Length along Smith River at elev. 985. . . . . . . . . . 16 miles Length of shoreline at elev. 985 . . . . . . . . . . . .110 miles Maximum width at elev. 985 . . . . . . . . . . . . . . 0.75 miles Storage: Acre-feet Inches Total volume at elev. 1014. . . . . . . . . 318,300 28.2 Uncontrolled flood storage (elev. 1014 to elev. 985). . . . . . . . . . . . . . . 117,900 10.4 Controlled flood storage (elev. 985 to elev. 974) . . . . . . . . . . . . . . . . 34,200 3.0 Power drawdown (elev. 974 to elev. 920). . . 111,200 9.8 Volume at design minimum power pool (below elev. 920). . . . . . . . . . . . . 55,000 4.9 Surface area: Total area at elev. 998 . . . . . . . . . . . . . . . 4,060 ac. Maximum power pool (elev. 974). . . . . . . . . . . . 2,880 ac. Design minimum power pool (elev. 920) . . . . . . . . 1,350 ac. Original river area (below elev. 998) . . . . . . . . 310 ac. Dam Type. . . . . Concrete gravity with 120 ft. long ungated spillway Foundation. . . . . . . . . . . . . . . . . . Quartz mica schist Length. . . . . . . . . . . . . . . . . . . . . . . . . . 920 ft. Maximum height of dam . . . . . . . . . . . . . . . . . . 220 ft. Maximum width at base . . . . . . . . . . . . . . . . . . 166 ft. Sluices: Number. . . . . . . . . . . . Three,5 ft. 8 in. by 10 ft. 0 in. Sluice gates. . . . .Six (1 service and 1 emergency per outlet) slide gates, hydraulically operated. Total capacity at elev. 985 . . . . . . . . . . . 13,350 c.f.s. Low flow outlets: Number. . . . . . . . . . . . . . . .Two, circular, 12 in. I.D. Gates . . . . . . . Four (1 service and 1 emergency per outlet) iron body gate valves; 3 manually operated, 1 electrically operated. Total capacity at elev. 985 . . . . . . . . . . . . . 80 c.f.s. Spillway energy dissipator: Type . . . . . . . . . . . . . . . . . . . . . Stilling basin Length . . . . . . . . . . . . . . . . . . . . . . . . 189 ft. Elevation of end sill . . . . . . . . . . . . . . .806 ft. msl. Elevation of bottom . . . . . . . . . . . . . . . .790 ft. msl. Power Plant: Rated generating capacity: 2 units at 6700 kw each . . . . . . . . . . . . . . . 13,400 kw 1 unit at 600 kw . . . . . . . . . . . . . . . . . . 600 kw Total . . . . . . . . . . . . . . . . . . . . . . . . 14,000 kw Principal dimensions: Power house . . . . . . . . . . . . . . . . . . 86 ft. x 76 ft. Generator room. . . . . . . . . . . . . . . . . 82 ft. x 32 ft. Intakes: Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Gates . . . . . . . . . . . . . Slide type, fixed cable hoists Penstocks: Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Type . . . . . . . . . . . . . . . . . . . . . . . .Welded steel Dimensions: For 6700 kw units. . . . . . . . . . . . . . . . . 9'-0" Dia. For 600 kw unit. . . . . . . . . . . . . . . . . . 3'-0" Dia. Hydraulic turbines: Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Type . . . . . . . . . . . . . . . . . . Francis, vertical shaft Rated capacity 2 units at 9400 hp each at 152 ft. net head. . . . .18,800 hp. 1 unit at 860 hp at 152 ft. net head . . . . . . . . 860 hp. Total. . . . . . . . . . . . . . . . . . . . . . . .19,660 hp. Discharge at rated turbine capacity (152 ft. net head): 9400 hp units - 605 c.f.s. x 2 units . . . . . . . 1210 c.f.s. 860 hp unit - 55 c.f.s. x 1 unit . . . . . . . . . 55 c.f.s. Total discharge. . . . . . . . . . . . . . . . . . 1265 c.f.s. Normal speed: 9400 hp units. . . . . . . . . . . . . . . . . . . . . 277 RPM 860 hp units . . . . . . . . . . . . . . . . . . . . . 720 RPM Draft tubes: Type: Main units . . . . . . . . . . . . . . . . . .Concrete below Secondary unit. . . . . . . . . . . . . .Conical plate steel Approximate throat diameter: Main units . . . . . . . . . . . . . . . . . . . . . . 5'-5" Secondary unit . . . . . . . . . . . . . . . . . . . .1'-11" Horizontal length (center line of main unit turbines to downstream face) . . . . . . . . .24'-0" Net area at outlet opening (9400 hp. units). . . . 142 sq. ft. Transformer: Type.3 phase, 60 cycle, oil immersed, inert gas filled, air cooled. 13.2 - 138 kv . . . . . . . . . . . . . (series connection) 13.2 - 69 kv . . . . . . . . . . . . . (multiple connection) Rating: 14,000 kva, self cooled 17,500 kva force cooled Switchyard: Size . . . . . . . . . . . . . . . . . . . . . . . . 55' x 54' Outgoing lines . . . . . . . . . . 1-132 kv, 3 phase, 60 cycle