in 1991, the Stormwater Quality Management Committee has administered
several stormwater monitoring programs that are delegated to
the local municipalities. These programs include an Illegal/Illicit
Connection Detection and Elimination Program, a "Wet Weather"
sampling program, and a "Dry Weather" sampling program.
These programs are intended to assess and characterize stormwater
quality conditions in key washes and storm channels of the municipal
storm sewer system. They also provide knowledge and feedback
which can be used to determine the overall effectiveness of
adopted municipal Best Management Practices
or BMPs to manage our storm sewer system and maximize stormwater
an effort to coordinate and characterize stormwater quality
conditions in the storm system and the Las Vegas Wash, the Stormwater
Quality Management Committee and Clark County Regional Flood
Control District has consolidated its municipal stormwater permit
monitoring program with several local agencies. These agencies
include the U.S. Bureau of Reclamation, US Geological Survey,
Nevada Division of Environmental Protection, City of Henderson,
City of Las Vegas, Clark County Sanitation District, Southern
Nevada Water Authority and Las Vegas Wash Coordination Committee.
coordination will allow resources and data to be shared between
the agencies, thereby improving efficiency, increasing effectiveness,
and reducing the overall cost of the monitoring programs.
learn more about the coordinated efforts to monitor water quality
Vegas Wash Coordination Committee's website
Connection Detection and Elimination Program
goal of the Illegal/Illicit Connection Detection and Elimination
Program consists of two primary objectives:
Annual field investigations designed to identify potential illegal
discharges, illicit connections, or illegal dumping of wastes
into the municipal storm sewer system.
Follow-up activities with dischargers or dumpers to assure that
the practice is eliminated.
the most part, these field inspection and enforcement activities
are performed by industrial pretreatment program staffs of the
individual municipalities, which are Co-Permittees to the NPDES permit. They
have the responsibility to respond to citizen complaints, conduct
inspections, educate property and business owners, and take
enforcement action when necessary.
the first nine years, the Illegal/Illicit Connection Detection
and Elimination Program has found very few instances of prohibited
or illegal activity. It has found that illegal connections and
discharges are a minor problem in the Las Vegas Valley, and those
that are found are eliminated quickly.
goal of the wet weather monitoring program is to sample for
pollutants in the municipal storm sewer system during a rain
storm. When it rains, pollutants such as oil, pesticides, sediment,
and bacteria are picked up from streets, parking lots, and lawns
and carried into the storm drain system. These pollutants then
flow straight to the Las Vegas Wash and ultimately to Lake Mead.
When the flow in the channel rises to a predetermined level,
an automated sampler activates and pumps water from the Las Vegas Wash into a 100ml bottle. A new jar is filled every
3-5 minutes depending on the site. Samples are collected within the first few hours of runoff. Samples are then bottled and delivered to a laboratory for analysis.
Automated samplers are located near the Las Vegas Wash downstream from the Desert Rose Golf Course and upstream from Lake Las Vegas. The baseline stormwater quality data obtained during rain storm events will help provide us with a better understanding of the types and amount of pollutants carried by stormwater and aid us in developing improved Best Management Practices (BMPs) to improve stormwater quality in the Las Vegas Valley.
frequent inspections and maintenance, automated samplers occasionally
malfunction due to vandalism or battery failure. In addition,
many storms do not generate sufficient flow depth to activate
the pump in the automated sampler. When sampling equipment is
not functioning properly or not effective, samples are taken
by hand from the channels. These samples are then composited
in the laboratory for analysis. The objective is to sample at least 3
storms per year at each site.
Dry Weather Monitoring
In addition, water samples are taken at the major outfalls to the Las Vegas Wash quarterly at times when flow is not affected by rainfall. Dry weather surface runoff is the result of water entering the municipal storm sewer from every day activities such as lawn watering, car washing, and ground water seepage. The dry weather-monitoring program has two primary objectives:
1. To target potential illegal or
illicit discharges to the municipal storm sewer system
(e.g., from industrial activity).
2. To develop a baseline of dry weather surface water quality
data against which future changes can be measured and which
can be used to compute urban pollutant concentrations in the
Las Vegas Wash.
Dry weather sampling is an effort to isolate potential illegal
discharges. Occasionally, people knowingly or unknowingly discharge
hazardous waste or other non-storm related waste into the municipal
storm sewer system. If excessive amounts of hazardous pollutants
are detected, code enforcement officers from the individual
municipalities can trace the source of the activities and make
corrective or enforcement actions if necessary.
Measuring and characterizing urban pollutants as they enter
the municipal storm sewer over time is also important. Based
on the sampling results and qualitative factors, the Committee
can determine the overall effectiveness of Best Management Practices
as well as develop improvements. The ongoing monitoring programs
continue to be an effective tool in understanding the impact
of urban runoff on downstream water quality.
Samples collected during Wet and Dry Weather monitoring
are analyzed using identical methodologies in the Laboratory.
These samples are tested for specific pollutants generally associated
with urban activity such as oil, bacteria, and pesticides. Levels
of these pollutants tend to increase with the level of urban
development in the Las Vegas Valley. The following pollutants
are associated with urban development and activities, and are
frequently found in stormwater:
Organic Compounds (VOC)
Organic Compounds (SOC)