SMITH MOUNTAIN LAKE

An aerial view of the lake

Photo.
Photo: State Water Control Board, Virginia  
 
 

A. LOCATION

Virginia, USA.
37:2-37:1 N, 79:2-79:5W; 238 m above sea level.

B. DESCRIPTION

Since the mid-1960's, when Smith Mountain Lake was first filled, the lake has been a very popular and important multipurpose resource. An important function of Smith Mountain Lake, and the primary reason for its creation, is to provide hydroelectric power. Appalachian Power Company owns and operates Smith Mountain Dam as well as the dam on Leesville Lake just downstream from Smith Mountain. The two lakes together make it possible to operate Smith Mountain Dam as a "pumped storage" operation. In this arrangement water can be pumped from Leesvile Lake back into Smith Mountain Lake during periods of low power usage. AP Co. can thus be prepared for peak periods of power demand because the "power pool" in Smith Mountain Lake has been maintained at a high level.
Smith Mountain Lake is also a very popular recreation site, serving people from throughout the western part of Virginia. Thousands enjoy boating, swimming, fishing and other activities on the lake every year. Many resort homes, condominiums and year-round residences are located on the shores of this reservoir. A significant economic impact on localities around the lake results from recreational businesses, construction of homes and resorts, and the addition of new residents to the communities growing around the shoreline.
Smith Mountain Lake is presently used as a public water supply The water and shoreline of the lake provide habitat for many aquatic plants and animals, as well as birds and other terrestrial wildlife. The protection of aquatic life and other uses already mentioned for this lake is the goal of lake management activities.
Two rivers, the Blackwater and the Roanoke, are the main tributaries to Smith Mountain Lake. The Roanoke River is the larger of the two tributaries and drains a watershed that includes the Roanoke Metropolitan area. The Blackwater River's drainage is mostly rural and agricultural. A 1980 study indicated 72% of the phosphorus loading to Smith Mountain Lake came from the Roanoke River, and that at least 90% of this load was non-point source in origin. Recommendations were made and some of these were implemented. The Blackwater River arm of the lake was also found to have a relatively high eutrophication rate in its upper reach, a result attributed largely to non- point source. Agriculture was the biggest contributor of nutrients from runoff, with dairy farms yielding the highest loads per acre. Progress has been made in controlling some agricultural sources of nutrients through the State Water Control Board agricultural no-discharge permit program. In recent years, a number of these permits, which require approved methods for storage and disposal of liquid animal wastes, have been issued in the Blackwater River drainage area (Q).

C. PHYSICAL DIMENSIONS

     
    Surface area [km2] 81
    Volume [km3] 2.8
    Maximum depth [m] 61.0
    Mean depth [m] 35.1
    Water level Regulated
    Length of shoreline [km] 805
    Residence time [yr] 3.2-3.5
    Catchment area [km2] 2,570
     
 

D. PHYSIOGRAPHIC FEATURES

D1 GEOGRAPHICAL
Sketch map: Fig. NAM-37-0l.
Number of outflowing rivers and channels (name): 1 (Roanoke R.).
D2 CLIMATIC Climatic data at Richmond
Mean temp. [deg C]
     
    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann.
    3.7 4.4 8.2 13.9 19.2 23.7 25.6 24.7 21.2 15.1 9.2 4.3 14.4
     
Precipitation [mm]
     
    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann.
    88 74 87 80 94 95 142 141 93 76 77 75 1,122

    Fig. NAM-37-01
    Sketch map of the lake.
 

Water temperature [deg C]
Dam station, 1987
[m]

     
    Depth Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    1 - - - 13 - 26 - 28 - 17 - -
    10 - - - 13 - 13 - 16 - 17 - -
    20 - - - 9 - 11 - 14 - 16 - -
    30 - - - 7 - 9 - 13 - 14 - -
    40 - - - 6 - 7 - 12 - 13 - -
    50 - - - 6 - 6 - - - 12 - -
    60 - - - 5 - - - - - 12 - -
     
Freezing period: None.
Notes on water mixing and thermocline formation
Occasional thermocline, but pumped-storage system causes lake to be vertically homogeneous.

E. LAKE WATER QUALITY (Q)

E1 TRANSPARENCY [m]
Dam station, 1987
[m]
     
    Depth Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    - - - 1.3 - 3.0 - 2.6 - 2.9 - -
     
E2 pH Dam station, 1987 [m]
     
    Depth Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    0.3 - - - 8.2 - 8.7 - 8.3 - 7.6 - -
    30.0 - - - 7.8 - 7.7 - 6.6 - 7.4 - -
    60.0 - - - 7.7 - 7.7 - 6.8 - 7.4 - -
     
E4 DO [mg l-1]
Dam station, 1987
[m]
     
    Depth Apr Jun Aug Oct
    1 11 (13)* 9 (26) 9 (28) 6 (17)
    10 10 (13) 8 (13) 4 (16) 6 (17)
    20 10 (9) 8 (11) 3.5 (14) 3 (15)
    30 9 (7) 8 (9) 3 (13) 2 (14)
    40 9 (6) 7 (7) 1.5 (12) 0 (13)
    50 9 (6) 6 (6) N.D. 0 (12)
    55 - 6 (6) 0.4 (10) 0 (12)
    60 8 (5) N.D. N.D. 0 (12)
    * Temperature [deg C].
E6 CHLOROPHYLL CONCENTRATION [micro l-1]
Dam station, 1987
[m]
     
    Depth Apr Jun Aug Oct
    0.3 0.31 0.60 1.5 N.D.
    15 stations, August 1987: 8.65 òÂ7.54.
E7 NITROGEN CONCENTRATION
Total Kjeldahl-N [mg l-1]
Dam station, 1985-1987
     
    [m] 1985 1986 1987
    Depth Apr Jun Aug Oct Apr Jun Aug Oct Apr Jun Aug Oct
    0.3 0.3 0.3 0.2 0.3 0.3 0.5 0.3 0.2 0.3 0.3 0.2 0.2
     
E8 PHOSPHORUS CONCENTRATION
Total-P [mg l-1]
Dam station, 1985-1987
     
    [m] 1985 1986 1987
    Depth Apr Jun Aug Oct Apr Jun Aug Oct Apr Jun Aug Oct
    0.3 .01 .01 .01 .01 .02 .01 .01 .03 .02 .01 .01 <.01
     
 

F. BIOLOGICAL FEATURES (Q)

F1 FLORA
Phytoplankton
Dam station, 1973
     
    Sampling date Dominant genera Cells Chlorophyll a
    [ml l-1] [micro g l-1]
    4 Apr 1973 Stephanodiscus 4,329 4.3
    Flagellates 2,029
    Melosira 433
    Ankistrodesmus 352
    synedra 189
    Others 163
    Total 7,495
    16 Jul 1973 Lyngbya 7,994 3.9
    Chroococcus 2,858
    Raphidiopsis 2,501
    Flagellates 1,474
    Synedra 1,279
    Other 2,679
    Total 18,801
    26 Sep 1973 Flagellates 1,325 3.7
    Raphidiopsis 564
    Merismopedia 536
    Dactylococcopis 479
    Stephanodiscus 423
    Other 722
    Total 4,094
     
F2 FAUNA
Fish
Stripped bass* (Mofone saxatillis), large mouth bass (Micropterus salmoides), small mouth bass (Micropterus dolomieui), shad (Dorosoma alosa).
* Economically important.
F3 PRIMARY PRODUCTION RATE [mg C m3 day-1]
Dam station, 1966-1967
     
    [m] 1966 1967
    Depth May Jul Aug Nov Aug
    Surface 9.8 24.3 38.8 19.5 13.9
    1 19.7 42.9 34.6 20.2 10.8
    2 17.6 26.7 41.4 18.0 21.2
    5 17.1 44.9 28.4 2.1 14.0
    8 5.0 6.0 1.8 0.0 19.8
    10 0.7 1.0 0.0 0.0 3.0
    12 0.0 0.0 0.0 0.0 0.0
     
 

G. SOCIO-ECONOMIC CONDITIONS (Q)

G1 LAND USE IN THE CATCHMENT AREA*
1980
     
    Smith Mountain Lake Basin
    Area [km2] [%] Water Supply Plan [%]
    Natural landscape 4,050.48 57.2
    Forest 60.7
    Agricultural land
    Orchard, etc. 278.28 3.9
    Crop field 1,954.55 27.6 8.4
    Pasture land 18.6
    Residential area 306.80 4.3
    Urban 10.7
    Uncategorized 41.77 0.6
    Water 447.56 6.3 1.7
    Total 7,079.44 100
    * Study area: 41% of Smith Mountain Lake drainage area.
Types of important forest vegetation
Pine, mixed hardwood forests (most forestland has been harvested at least one time and is in a continual regrowth cycle).
Main kinds of crops
Pasture, orchards, corn, tobacco, hay, alphalfa, fallow/inactive.
Levels of fertilizer application on crop fields: Moderate.
Trends of change in land use
Development of shoreline for residential/recreational use and continuing urbanization of Roanoke area.
G2 INDUSTRIES IN THE CATCHMENT AREA AND THE LAKE
     
    No. of Main products or
    establishments major industries
    Primary industry Wood product, tobacco,
    fruits
    Dairy farms 60-70
    Secondary industry Plastics, petroleum
    Tertiary industry Recreational
     
Number of domestic animals in the catchment area
Cattle 55,000.
G3 POPULATION IN THE CATCHMENT AREA
1984
     
    Population Major cities
    Population density [km-2] (population)
    Urban 225,000 Roanoke, Salem, Bedford
    Rural 15,209
    Total 240,209 93.5
     
 

H. LAKE UTILIZATION (Q)

H1 LAKE UTILIZATION
Source of water and recreation (swimming, sport-fishing and yachting).
H2 THE LAKE AS WATER RESOURCE
1988: Domestic water, irrigation, industrial water and power plant.

I. DETERIORATION OF LAKE ENVIRONMENTS AND HAZARDS

I1 ENHANCED SILTATION
Extent of damage: Not serious.
Supplementary notes: Localized development problems with runoff.
I2 TOXIC CONTAMINATION
Present status: Detected but not serious.
Environmental quality standards for contaminations in the lake
Surface Public Water Supply Standards*
     
    Constituent Concentration [mg l-1]
    Arsenic 0.05
    Barium 1.0
    Cadmium 0.01
    Chloride 250
    Chromium (total) 0.05
    Copper 1.0
    Foaming agents
    (as methylene blue
    active substances) 0.5
    Iron 0.3
    Lead 0.05
    Manganese (soluble) 0.05
    Mercury 0.002
    Nitrate (as N) 10
    Phenols 0.001
    Selenium 0.01
    Silver 0.05
    Sulfate 250
    Total dissolved solids 500
    Zinc 5.0
    Endrin 0.0002
    Lindane 0.004
    Methoxychlor 0.1
    Toxaphene 0.005
    2, 4-D 0.1
    Silvex 0.01
     
* Data from Commonwealth of Virginia Water Quality Standards.
Water quality criteria - metals in water*
     
    Substance Value [micro g l-1]
    Arsenic (trivalent) 190
    Cadmium 0.7852 (ln (hardness))-3.49
    Chromium (hexavalent) 11
    Copper 0.8545 (ln (hardness))-1.465
    Iron 1000
    Lead 1.266 (ln (hardness))-4.661
    Nickel 0.76 (ln (hardness))+1.06
    Selenium (total inorganic) 35
    Zinc(total) 47
    * Data from Commonwealth of Virginia Water Quality Standards.
Other standards (national)
Fish tissue contamination standards, Water quality standards for drinking water and swimming.
I3 EUTROPHICATION
Nuisance caused by eutrophication
Algal blooms in early 1970's - attributed to sewage treatment plants in Roanoke Valley upstream.
Nitrogen and phosphorus loadings to the lake [kg yr-1] EPA document, 1973
     
    Sources Industrial Total
    T-N (TKN) 33,215 2,262,870
    T-P 5,475 180,360
     
Supplementary notes
Complete upgrading of STP's in Roanoke River Basin, tracking through the NPDES (National Pollution Discharge Elimination System) permit system. Development of zoning regulations surrounding lake.
I4 ACIDIFICATION
Extent of damage: None.
Past trends in hydrogen ion concentration in lake water
The pH value is quite stable in many data.

J. WASTEWATER TREATMENTS (Q)

J1 GENERATION OF POLLUTANTS IN THE CATCHMENT AREA
    d) Measurable pollution with limited wastewater treatment.
J2 APPROXIMATE PERCENTAGE DISTRIBUTION OF POLLUTANT LOADS
     
    [%]
    Non-point sources 90
    Point sources 10
    (21 industrial discharges)
     
J3 SANITARY FACILITIES AND SEWERAGE Percentage of municipal population in the catchment area provided with adequate sanitary facilities (on.site treatment systems) or public sewerage: 100%. Municipal wastewater treatment systems No. of secondary treatment systems: 22. No. of primary treatment systems: 9. Industrial wastewater treatment systems No.of industrial wastewater treatment systems: 11 (no "typical" system - depends on facility).

L. DEVELOPMENT PLANS

Smith Mountain Lake Shoreline Management Plan, 1985; Comprehensive Management Plan for land use sewerage system requirements, erosion and sedimentation controls; flood plain ordinances; subdivision ordinances; etc.

M. LEGISLATIVE AND INSTITUTIONAL MEASURES FOR UPGRADING LAKE ENVIRONMENTS (Q)

M2 INSTITUTIONAL MEASURES
  1. Virginia Water Control Board, West Central Regional Office
  2. Smith Mountain Lake Shoreline Management Plan Technical Advisory Committee and West Piedmont Planning District Commission Staff
 

N. SOURCES OF DATA

  1. Questionnaire filled by Dr. Robert T. Ray, Office of Environmental Research and Standards, Commonwealth of Virginia, State Water Control Board.
  2. Sligh, D. W. & Liptak, T. L. (1988) Lake Monitoring Program 1987. West Central Region. Virginia Water Control Board. 40 pp.
  3. Smith Mountain Lake Technical Advisory Committee & West Piedmont Planning District Commission (1985) Smith Mountain Lake Shoreline Management Plan, I & II.
  4. U.S. Environmental Protection Agency (1975) Report on Smith Mountain Reservoir, Bedford, Franklin and Pittsylvania Counties, Virginia. Working Paper 465.
  5. Simmons G. M. & Neff, S. E. (1969) The Effect of Pumped-straged Reservoir Operation on Biological Productivity and Water Quality. Water Resources Research Centre, Virginia Polytechnic Institute Bulletin 21.
  6. Virginia Water Control Board (1980) The Impact of Non-point Sources on the Water Quality of Smith Mountain Lake. West Central Regional Office Planning Bulletin 329.
  7. Court, A. (1974) The climate of the conterminous United States. "World Surveys of Climatology Volume 11, Climates of North America" (ed. Bryson, R. A. & Hare, F. K.), p. 337. Elsevier Scientific Publishing Company Amsterdam-London-New York.