NAC445A.2158. Colorado Region: Las Vegas Wash at Lake Mead.

The limits of this table apply to the body of water known as the Las Vegas Wash from Telephone Line Road to its confluence with Lake Mead. This segment of the Las Vegas Wash is located in Clark County.

STANDARDS OF WATER QUALITY •

Las Vegas Wash at Lake Mead

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
Aquatic Life Species of Concern						Excluding fish, this does not preclude the establishment of a fishery.
Temperature ΔTb - °C	DT	= 0
pH - SU				S.V.	6.5 - 9.0	X	X	*					*
Dissolved Oxygen - mg/l				c		X		*		X			X
Nitrogen Species (as N) - mg/l	Total Inorganic Nitrogen 95% of S.V. samples ≤ 17			Nitrate S.V. Nitrite S.V.	≤ 100 ≤ 10	*							X
Suspended Solids - mg/l				S.V.	≤ 135d			*
Total Dissolved Solids - mg/l	95% of S.V. samples ≤ 2400			S.V.	≤ 3000	*	X									X
Fecal Coliform - MF or MPN/100 ml				e		X	X			*			X

* = The most restrictive beneficial use.

X = Beneficial use.

• The goal of the standards set forth in this table is to ensure that the beneficial uses for the body of water described in this section will include, without limitation, the propagation of aquatic life, including, without limitation, fish by the next triennial review required by the Clean Water Act, 33 U.S.C. §§ 1251 et seq.

^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     Aerobic conditions are desirable for the beneficial uses of propagation of aquatic life, excluding fish, watering of livestock, recreation not involving contact with water and propagation of wildlife. So as not to prevent the development and restoration of marshes and wetlands in the Las Vegas Wash, aerobic conditions are established as a goal rather than a standard and the goal is not intended to preclude development of a limited fishery in selected areas. Aerobic conditions is intended to mean the absence of objectionable odors that may be caused by wastewater discharges in excess of existing odors.

^d     Suspended solids standard does not apply when flows are greater than 110 percent of average flow as measured at the nearest gage. “Average flow” is defined as the 12-month rolling average of the average monthly flow.

^e     Any discharge from a point source into the Las Vegas Wash must not exceed a log mean of 200 per 100 milliliters based on a minimum of not less than five samples taken over a 30-day period, nor may more than 10 percent of the total samples taken during any 30-day period exceed 400 per 100 milliliters.

     (Added to NAC by Environmental Comm’n by R160-06, eff. 8-26-2008)