There are several water quality monitoring programs that are implemented in the Las Vegas Valley. These programs include an Illicit Discharge Detection and Elimination (IDDE) Program, a wet weather sampling program and a dry weather sampling program. These programs are intended to assess and characterize water 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 improve stormwater quality.
The goal of the Illicit Discharge Detection and Elimination (IDDE) Program are to:
1. Conduct annual field investigations designed to identify potential illegal discharges, illicit connections, or illegal dumping of wastes into the municipal storm sewer system, and
2. Follow-up on 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 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.
Overall, 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.
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 sampling 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 Club at Sunrise Golf Course and upstream from Lake Las Vegas. The baseline stormwater quality data obtained during rain storm events help provide an understanding of the types and amounts of pollutants carried by stormwater and aid us in developing improved Best Management Practices (BMPs) to improve stormwater quality in the Las Vegas Valley.
In addition, water samples are taken at the major outfalls to the Las Vegas Wash on a quarterly basis 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 is conducted by the Southern Nevada Water Authority and 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 as well as to characterize the water quality in the drainages. 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.