Stormwater Quality Management Committee
Clark County Regional Flood Control District
600 S. Grand Central Pkwy. Las Vegas, NV 89106

Monitoring Programs

Beginning 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 quality conditions.

Cooperative Efforts

In 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.

This 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.

To learn more about the coordinated efforts to monitor water quality visit Las Vegas Wash Coordination Committee's website .

Illegal/Illicit Connection Detection and Elimination Program

The goal of the Illegal/Illicit Connection Detection and Elimination Program consists of two primary objectives:

1. Annual field investigations designed to identify potential illegal discharges, illicit connections, or illegal dumping of wastes into the municipal storm sewer system.

2. Follow-up activities with dischargers or dumpers to assure that the practice is eliminated.

For 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.

During 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.

Wet Weather Monitoring

The 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.

Despite 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.

Sampling Parameters

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:

Pollutants Analyzed

Ammonia - Nitrogen Oil and Grease
Boron Pesticides
Copper Nitrite
Fecal Coliforms TKN
Fecal Streptococcus Total Dissolved Solids
Herbicides Total Nitrogen
Dissolved Copper Total Phosphorus
Dissolved Lead Total Suspended Solids
Dissolved Zinc Zinc
Lead Volatile Organic Compounds (VOC)
Nitrate Semi-Volatile Organic Compounds (SOC)

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