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Nevada Administrative Code (Last Updated: January 6, 2015) |
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Chapter445A Water Controls |
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WATER POLLUTION CONTROL |
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Standards for Water Quality |
NAC445A.1626. Truckee Region: Lake Tahoe.
- The limits of this table apply to the body of water known as Lake Tahoe for its existing sampling points. This segment of Lake Tahoe is located in Carson City and Douglas and Washoe Counties.
STANDARDS OF WATER QUALITY
Lake Tahoe
PARAMETER
REQUIREMENTS
TO MAINTAIN
EXISTING HIGHER
QUALITY
WATER QUALITY
STANDARDS FOR
BENEFICIAL USES
Beneficial Usea
Livestock
Irrigation
Aquatic
Contact
Noncontact
Municipal
Industrial
Wildlife
Aesthetic
Enhance
Marsh
Beneficial Uses
X
X
X
X
X
X
X
X
X
Aquatic Life Species of Concern
Cold-water fishery.
Temperature - °C
DTb - °C
S.V. Oct-May
S.V. Jun-Sep
DT
≤ 10.0
≤ 20.0
= 0
*
X
pH - SU
S.V.
7.0-8.4
X
X
*
*
X
X
*
Dissolved Oxygen -
percent of saturation
S.V.
≥ 90.0
X
*
X
X
X
X
Soluble Phosphorus - μg/l
A-Avg.
≤ 7.0
*
X
X
X
Nitrogen Species
(as N) - mg/l
Nitrite S.V.
Total Nitrogen
A-Avg.
S.V.
≤ 0.06
≤ 0.25
≤ 0.32
X
*
*
X
Total Soluble Inorganic Nitrogen - μg/l
A-Avg.
≤ 25.0
*
X
X
*
X
Unionized Ammonia - mg/l
S.V.
≤ 0.003
*
X
Algal Growth Potential
f
*
Plankton Count - No./ml
Avg. (Jun-Sep)
S.V.
≤ 100.0
≤ 500.0
*
Turbidity
c
*
*
Clarity
d
*
X
Total Dissolved
Solids - mg/l
A-Avg.
S.V.
≤ 60.0
≤ 70.0
X
X
*
Chloride - mg/l
A-Avg.
S.V.
≤ 3.0
≤ 5.0
X
*
X
X
Sulfate - mg/l
S.V.
≤ 2.0
*
Sodium - SAR
A-Avg.
≤ 8.0
*
Specific Electrical Conductance μmhos/cm@20°C
A-Avg.
S.V.
≤ 95.0
≤ 105.0
*
E. coli - No./100 ml
S.V.
≤ 126.0
*
X
Coliform Organisms -
MPN/100 ml
e
X
X
*
X
X
X
* = The most restrictive beneficial use.
X = Beneficial use.
a Refer to NAC 445A.122 and 445A.1622 for beneficial use terminology.
b Maximum allowable increase in temperature above water temperature at the boundary of an approved mixing zone, but the increase must not cause a violation of the single value standard.
c To minimize turbidity levels in Lake Tahoe and tributary streams and control erosion:
1 The discharge of solid or liquid waste materials including soil, silt, clay, sand and other organic and earthen materials to Lake Tahoe or any tributary thereto is prohibited.
2 The discharge of solid or liquid waste materials including soil, silt, clay, sand and other organic and earthen materials to lands below the high water rim of Lake Tahoe or along any tributary to Lake Tahoe in a manner which will cause the discharge of the waste materials to Lake Tahoe or any tributary thereto is prohibited.
3 The placement or man-made disturbance of material below the high water rim of Lake Tahoe or along any tributaries to Lake Tahoe in a manner which will cause the discharge of solid or liquid waste materials including soil, silt, clay, sand and other organic and earthen materials to Lake Tahoe or any tributary thereto is prohibited.
d The vertical extinction coefficient must be less than 0.08 per meter when measured at any depth below the first meter. Turbidity must not exceed 3 NTU at any point of the lake too shallow to determine a reliable extinction coefficient.
e A density not greater than the values shown in the following table:
Median Maximum
Undeveloped Lake Front Areas
10 yards offshore 5.0 32.0
100 yards offshore 3.0 15.0
Developed Lake Front Areas
10 yards offshore 240.0 700.0
100 yards offshore 15.0 64.0
Directly Influenced by Streams
10 yards offshore 240.0 700.0
100 yards offshore 32.0 240.0
f The mean annual algal growth potential at any point in the lake must not be greater than twice the mean annual algal potential at a limnetic reference station and using analytical methods determined jointly with the Environmental Protection Agency, Region IX.
(Added to NAC by Environmental Comm’n by R160-06, eff. 8-26-2008)