Nevada Administrative Code
Chapter 445A - Water Controls
WATER POLLUTION CONTROL
Standards for Water Quality
Section 445A.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 | [LESS THEN OR EQUAL TO] 10.0 [LESS THEN OR EQUAL TO] 20.0 = 0 | * | X | |||||||||||
| pH - SU | S.V. | 7.0-8.4 | X | X | * | * | X | X | * | ||||||
| Dissolved Oxygen - percent of saturation | S.V. | [GREATER THEN OR EQUAL TO] 90.0 | X | * | X | X | X | X | |||||||
| Soluble Phosphorus - µg/l | A-Avg. | [LESS THEN OR EQUAL TO] 7.0 | * | X | X | X | |||||||||
| Nitrogen Species (as N) - mg/l | Nitrite S.V. Total Nitrogen A-Avg. S.V. | [LESS THEN OR EQUAL TO] 0.06 [LESS THEN OR EQUAL TO] 0.25 [LESS THEN OR EQUAL TO] 0.32 | X | * | * | X | |||||||||
| Total Soluble Inorganic Nitrogen - µg/l | A-Avg. | [LESS THEN OR EQUAL TO] 25.0 | * | X | X | * | X | ||||||||
| Unionized Ammonia - mg/l | S.V. | [LESS THEN OR EQUAL TO] 0.003 | * | X | |||||||||||
| Algal Growth Potential | f | * | |||||||||||||
| Plankton Count - No./ml | Avg. (Jun-Sep) S.V. | [LESS THEN OR EQUAL TO] 100.0 [LESS THEN OR EQUAL TO] 500.0 | * | ||||||||||||
| Turbidity | c | * | * | ||||||||||||
| Clarity | d | * | X | ||||||||||||
| Total Dissolved Solids - mg/l | A-Avg. S.V. | [LESS THEN OR EQUAL TO] 60.0 [LESS THEN OR EQUAL TO] 70.0 | X | X | * | ||||||||||
| Chloride - mg/l | A-Avg. S.V. | [LESS THEN OR EQUAL TO] 3.0 [LESS THEN OR EQUAL TO] 5.0 | X | * | X | X | |||||||||
| Sulfate - mg/l | S.V. | [LESS THEN OR EQUAL TO] 2.0 | * | ||||||||||||
| Sodium - SAR | A-Avg. | [LESS THEN OR EQUAL TO] 8.0 | * | ||||||||||||
| Specific Electrical Conductance µmhos/cm@20°C | A-Avg. S.V. | [LESS THEN OR EQUAL TO] 95.0 [LESS THEN OR EQUAL TO] 105.0 | * | ||||||||||||
| E. coli - No./100 ml | S.V. | [LESS THEN OR EQUAL TO] 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
NRS 445A.425, 445A.520
