In my last blog post, What Kind of Trash and Debris is in Stormwater Runoff?, I wrote about the types of trash found in stormwater and the effects trash and debris have on our environment and infrastructure.
Continuing with the topic of trash control; if your community is interested in developing a trash control strategy here are six key points that should be considered:
1. Identify all outfalls and estimate trash loads – This may seem obvious, but you need to build a database of all outfalls and estimated trash loads for each drainage basin. Only then will you know the true extent of the problem and have a baseline for measuring the effectiveness of your trash control strategy.
2. Identify high trash zones – It may not be practical or even necessary to apply treatment for every outfall. Identifying areas where trash is concentrated, such as illegal dumping sites, salvage yards, and other high trash areas will help narrow your focus and ensure your resources are concentrated on high-value sites.
3. Establish trash reduction goals – What is the end goal for your project? This could be to provide 100% removal of a targeted size of trash or larger, for example, a cigarette butt which is roughly 5mm. Another example of a reduction goal would be to reduce trash by a specific volume or weight over a period of time.
4. Choose sites and devices – This step involves selecting the drainage areas to be treated and the methods of treatment, including land based and/or manufactured BMPs. This will involve conducting a detailed analysis of the various treatment method options and selecting a system that will meet your goal and budget requirements. When analyzing treatment systems it is important to take into account maintenance costs when evaluating the life cycle expenses associated with the system. A word of caution, don’t make the assumption that land based BMPs are maintenance free. All BMPs, whether they are land based or manufactured, will require regular maintenance to ensure that they continue to function as designed.
5. Develop inspection & maintenance plan – This is often the most overlooked part of a trash control strategy. What is the inspection schedule and is there specific equipment that will be needed? Who will conduct inspections and maintenance? What are the consequences (fines) if inspections and maintenance are not performed as prescribed? These are all important questions that should be investigated when developing the maintenance plan.
6. Monitor – Regular monitoring will provide data to document load reduction and measure overall program performance Comparisons can be made of load reduction goals vs. actual results, allowing for program optimization.