What is stormwater monitoring?

What is stormwater monitoring?

Stormwater monitoring is a process of data collection to analyze stormwater runoff. Monitoring is used to determine the impacts of runoff on water quality.

Samples are typically taken from stormwater discharge points and are either quickly analyzed on site or sent to a lab for analysis.

Stormwater monitoring is used to detect pollutants and determine best practices to reduce the runoff of pollutants into waterways. Monitoring can help utilities and municipalities ensure compliance with environmental regulations and protect local water quality.

How is stormwater data collected?

Stormwater monitoring can use data gathered from discharge points, like storm drains. Samples are collected during rain events. The samples are then analyzed for pollutants like sediments, nutrients, metals and bacteria – either on site or in a lab.

The results are then compared to established standards.

What kind of data is used for stormwater monitoring?

Data used for stormwater monitoring includes:

• Water quality data from samples
• Flow measurements
• Precipitation data
• Visual observations

What kind of technology is used for stormwater monitoring?

Technologies used for stormwater monitoring have evolved over the years. Newer devices rely on innovative technologies such as Internet of Things (IoT), which is a network of physical objects that use sensors, software and remote connections to transfer data over the internet.

More traditional technologies are still used, such as flow meters, pressure sensors and even visual monitoring.

Technologies include:

• Flow meters
• Acoustic sensors
• Audio monitoring
• Water quality sensors (multiparameter, nutrient and heavy metal sensors)
• Ultrasonic sensors
• Radar flow meters
• Drones
• Satellite imaging and GIS mapping
• Soil moisture sensors
• Digital twins
• Visual monitoring

What is the purpose of stormwater monitoring?

The main purpose of stormwater monitoring is to assess and manage the impact of stormwater runoff on the environment. Runoff can carry pollutants into local water bodies. Stormwater monitoring can help identify sources of contamination and evaluate the effectiveness of stormwater systems.

Other purposes of stormwater monitoring include assessing the impacts of runoff on infrastructure and public health. Monitoring can help detect potential flood risks and optimize drainage systems and retention basins.

Stormwater monitoring can also help municipalities maintain compliance with regulations.

What are stormwater sampling requirements?

Industrial facilities with stormwater permit coverage typically must conduct sampling during a rain event.

A stormwater sample must be collected during a qualifying storm event (QSE). The U.S. Environmental Protection Agency (EPA) states that a QSE is a rainfall event with greater than 0.1 inches of rainfall that takes place at least 72 hours from the previous measurable rain event.

Samples are commonly collected at points where stormwater leaves the facilities property.

Common points for sample collection include:

• Ditches
• Swales adjacent to roadways
• Storm drains
• Culverts
• Retention ponds
• Erosion patterns leading off site

What is the purpose of stormwater management?

The purpose of stormwater management is to effectively control and use runoff. Stormwater management includes planning for runoff, maintaining systems, and regulation of the collection, storage and movement of stormwater.

Stormwater monitoring is a part of proper stormwater management. Both focus on protecting water quality and public health.

Like stormwater monitoring, key objectives for stormwater management include:

• Flood prevention and control
• Water quality protection
• Groundwater recharge and conservation
• Infrastructure protection
• Regulatory compliance
• Climate resilience
• Ecological protection and habitat conservation
• Public health and community benefits