Nevada Administrative Code › Chapter 445A - Water Controls › WATER POLLUTION CONTROL › Standards for Water Quality › Section 445A.2152 - Colorado Region: Lake Mead

Current through June 11, 2024
The limits of this table apply to the body of water known as
				  Lake Mead, excluding the area covered by NAC
				  445A.2154, Inner Las Vegas Bay.
				  Lake Mead is located in Clark County.
STANDARDS OF WATER QUALITY
Lake Mead
PARAMETER
REQUIREMENTS TO MAINTAIN EXISTING HIGHER
								QUALITY
WATER QUALITY CRITERIA TO PROTECT BENEFICIAL
								USES
Beneficial Usesa
Livestock
Irrigation
Aquatic
Contact
Noncontact
Municipal
Industrial
Wildlife
Aesthetic
Enhance
Marsh
Beneficial Uses
X
X
X
X
X
X
X
X
Aquatic Life Species of Concern
Warm-water fishery.
Temperature [DELTA]Tb -
								°C
[DELTA]T = 0
[DELTA]T<= 2
*
pH - SU
95% of S.V. samples <= 8.8
S.V. 6.5 - 9.0
*
Dissolved Oxygen - mg/L
S.V. >= 5.0c
*
Total Inorganic Nitrogen (as N) - mg/L
95% of S.V. samples <= 4.5
*
*
Nitrate (as N) - mg/L
S.V. <= 10
*
Nitrite (as N) - mg/L
S.V. <= 1
*
Total Ammonia (as N) -mg/L
d
*
Chlorophyll a - µg/L
e
*
*
Total Suspended Solids -mg/L
S.V. <= 25
*
Turbidity - NTU
f
S.V. <= 25
*
Color - PCU
g
*
Total Dissolved Solids -mg/L
Flow Weighted A-Avg. Concentration <= 723
								measured below Hoover Dam 
								h
S.V. <= 1000
*
Chloride - mg/L
S.V. <= 400i
*
Sulfate - mg/L
S.V. <= 500i
*
E. coli - cfu/100 mL 
								j
G.M. <= 126
S.V. <= 410
*
Fecal Coliform - No./100 mL
<= 200/400k
*
Toxic Materials
l
* = The most restrictive beneficial use.
X = Beneficial use.
a Refer to NAC
				  445A.122 and
				  445A.2142 for beneficial use
				  terminology.
b Maximum allowable increase in
				  temperature above water temperature at the boundary of an approved mixing
				  zone.
c Applies to the epilimnion when
				  stratified, or average in water column during periods of
				  nonstratification.
d The water quality criteria for
				  ammonia are specified in NAC
				  445A.118.
e The requirements for chlorophyll
a
are:
1 Not more than 1 monthly mean in
				  a calendar year at Station LWLVB 1.85 may exceed 45µg/L. Station LWLVB
				  1.85 is located at the center of the channel at a distance of 1.85 miles into
				  Las Vegas Bay from the confluence of the Las Vegas Wash with Lake Mead.
2 The mean for chlorophyll
a
in summer (July 1-September 30) must not exceed 40
				  µg/L at Station LWLVB 1.85, and the mean for 4 consecutive summer years
				  must not exceed 30 µg/L. The sample must be collected from the center of
				  the channel and must be representative of the top 5 meters of the channel.
				  Station LWLVB 1.85 is located at the center of the channel at a distance of
				  1.85 miles into Las Vegas Bay from the confluence of the Las Vegas Wash with
				  Lake Mead.
3 The mean for chlorophyll a in
				  the growing season (April 1-September 30) must not exceed 16 ìg/L at
				  Station LWLVB 2.7 and 9 ìg/L at Station LWLVB 3.5. Station LWLVB 2.7 is
				  located at a distance of 2.7 miles into Las Vegas Bay from the confluence of
				  the Las Vegas Wash with Lake Mead. Station LWLVB 3.5 is located at a distance
				  of 3.5 miles into Las Vegas Bay from the confluence of the Las Vegas Wash with
				  Lake Mead.
4 The mean for chlorophyll a in
				  the growing season (April 1-September 30) must not exceed 5 ìg/L in the
				  open water of Boulder Basin, Virgin Basin, Gregg Basin and Pierce Basin. The
				  single value must not exceed 10 ìg/L for more than 5 percent of the
				  samples.
5 Not less than two samples per
				  month must be collected between the months of March and October. During the
				  months when only one sample is available, that value must be used in place of
				  the monthly mean.
f Turbidity must not exceed that
				  characteristic of natural conditions by more than 10 NTU.
g Color must not exceed that
				  characteristic of natural conditions by more than 10 PCU.
h The salinity standards for the
				  Colorado River system are specified in NAC
				  445A.1233.
i The combination of this
				  constituent with other constituents comprising TDS must not result in the
				  violation of the TDS standards for Lake Mead and the Colorado River.
j The geometric mean must not be
				  exceeded in any 30-day period. The single value must not be exceeded in more
				  than 10 percent of the samples collected within any 30-day period.
k Based on a minimum of not less
				  than five samples taken over a 30-day period, the fecal coliform bacterial
				  level must not exceed a log mean of 200 per 100 milliliters, nor must more than
				  10 percent of the total samples taken during any 30-day period exceed 400 per
				  100 milliliters.
l The water quality criteria for
				  toxic materials are specified in NAC
				  445A.1236.
The Commission recognizes that at entrances of tributaries
				  to Lake Mead, localized [violations] exceedance of standards may
				  occur.
Added to NAC by
				  Environmental Comm'n by R160-06, eff. 8-26-2008; A by
				  R037-19A,
				  eff. 10/22/2019
NRS
				  445A.425,
				  445A.520