Nevada Stabilized Construction Approaches TC-1 Detail
Nevada is situated within one of the driest regions of the United States, making the protection of its limited surface water resources a significant concern. Much of the state lies within the Basin and Range Province, characterized by isolated mountain ranges and closed drainage basins. Many valleys in Nevada are endorheic, meaning water does not flow to the ocean but instead collects in internal basins, increasing the potential for pollutant concentration when contaminants are introduced. Northern and central mountainous areas receive the majority of the state’s precipitation, primarily as snow, which supplies runoff to rivers, wetlands, and groundwater systems.
The Humboldt River is Nevada’s longest river and drains approximately 16,900 square miles of land across northern Nevada. It flows westward through the central portion of the state and terminates in the Humboldt Sink, a basin that is intermittently dry. The river and associated wetlands provide essential habitat for migratory birds and wildlife. Other river systems, including the Reese River, collect snowmelt from higher elevations and provide seasonal water resources for irrigation and local ecosystems.
In southern Nevada, the Las Vegas Wash plays a critical role in conveying urban stormwater and treated effluent from the Las Vegas Valley to Lake Mead. The wash supports sensitive wetland habitat and functions as an essential natural filtration corridor. Regional organizations such as the Southern Nevada Water Authority and watershed advisory groups work alongside state and local agencies to protect and restore Nevada’s surface waters. Continued coordination among residents, industry, and government agencies is essential to maintaining water quality in this arid environment.
Nevada Division of Environmental Protection (NDEP) NPDES Stormwater Permits
The Federal Water Pollution Control Act, first enacted in 1948 and significantly amended in 1972 as the Clean Water Act, established the framework for regulating pollutant discharges to waters of the United States. One of the most significant outcomes of this legislation was the creation of the National Pollutant Discharge Elimination System permit program, which regulates discharges from municipal, industrial, and construction activities.
In Nevada, authority to administer the NPDES program has been delegated to the Nevada Division of Environmental Protection through the Bureau of Water Pollution Control. The Bureau issues the NVR100000 Construction Stormwater General Permit, which applies to most construction activities that disturb one acre or more of land or are part of a common plan of development of that size or greater. Operators must obtain permit coverage before beginning construction by submitting a Notice of Intent and preparing a Stormwater Pollution Prevention Plan.
The Stormwater Pollution Prevention Plan identifies potential sources of pollution on the site and outlines the Best Management Practices that will be implemented to prevent pollutants from being discharged into stormwater runoff. Multiple BMPs are often required to address a single pollution source. Soil erosion and sediment are among the most common contributors to construction-related water pollution, and construction site entrances are a frequent source of off-site sediment tracking. As a result, entrance stabilization, roadway sweeping, and drainage controls are critical components of Nevada construction SWPPPs.
NDEP maintains a Best Management Practices Toolbox that compiles manuals, guidance documents, and reference materials from state and local stormwater authorities. This resource supports contractors, engineers, and inspectors in designing, implementing, and enforcing stormwater controls under the NPDES program.
Stabilized Construction Approach: Construction Entrance/Exit Detail
A stabilized construction entrance or exit is typically one of the first BMPs installed on a construction site. Its purpose is to minimize sediment tracked onto public roadways from construction vehicles. These entrances function in conjunction with other erosion and sediment control measures, including street sweeping, sediment traps, silt fencing, and vehicle egress controls. Temporary construction entrances are required at all locations where vehicles exit the site directly onto paved roads or public rights-of-way.
All construction entrance BMPs require routine inspection and maintenance to remain effective. Entrances should be inspected regularly, following precipitation events, to confirm that sediment is being adequately controlled and that the entrance has not been damaged or compromised. Street sweeping is required for any material that escapes the entrance and is deposited onto active roadways.
Aggregate-Based Track Out Pad
The Nevada Department of Transportation Construction Site BMP Manual includes a stabilized construction entrance detail that utilizes a traditional aggregate-based track-out pad. This approach relies on crushed rock or gravel to create a rough surface that dislodges sediment from vehicle tires as they exit the site.
NDOT guidance specifies that aggregate entrances be constructed using crushed rock placed to a minimum depth of six inches and extending at least fifty feet in length. Aggregate should generally be two inches or larger in diameter and sized appropriately for the vehicles accessing the site. Smaller rocks can be tracked onto roadways or become lodged in dual-tire vehicles and expelled at high speeds, creating safety hazards.
Aggregate entrances must be monitored frequently, as the stone can become compacted and saturated with sediment. When the surface loses its roughness, additional aggregate must be added, or the entrance length extended. If a gravel entrance alone is insufficient to control sediment tracking, it must be supplemented with additional track-out control BMPs.
Tire Wash Systems
When aggregate entrances do not adequately remove sediment from vehicle tires, tire wash systems may be installed. Tire washes use pressurized water to remove remaining soil and debris as vehicles exit the site. These systems may be manual or automated, and some designs allow partial recycling of wash water to reduce consumption.
All wash water must be contained and directed to a sediment basin or other approved containment structure to prevent discharge from the site. Tire wash systems require ongoing maintenance, including removal of accumulated sediment from basins and cleaning of filters, to remain effective.
FODS Trackout Control System
The FODS Stabilized Construction Entrance System is a manufactured track-out control BMP designed to reduce sediment tracking from construction vehicles. The system consists of twelve-foot-wide by seven-foot-long high-density polyethylene mats with pyramid-shaped surface features. These features flex vehicle tires and open tread lugs, allowing sediment to be released and captured within the voids between the pyramids.
Unlike aggregate entrances, the FODS system does not compact over time and does not introduce loose rock to the site. The mats can be installed over soil, concrete, or asphalt and operate without the need for water or power. Because the system does not rely on aggregate, it eliminates the risk of stones being tracked onto active roadways or expelled from dual-tire vehicles.
A standard configuration utilizes a one-by-five T layout, approximately 35 feet in length, to replace a traditional 70-foot aggregate entrance while maintaining an adequate turning radius for exiting vehicles. The system is designed for rapid installation and can typically be deployed or relocated in under an hour. The mats are reusable and are intended for service lives of ten years or more, allowing contractors to reuse the same entrance across multiple phases and projects while maintaining compliance with stormwater requirements.