HOLDEN, MA - While technology for treating suspended solids in stormwater runoff continues to advance, the lack of common testing protocols has made it difficult to accurately gauge their performance and select the appropriate solutions.That's about to change with New Jersey's long-awaited new protocols for testing of stormwater solids removal devices.
The state's new rules provide a less expensive and more streamlined process for testing and evaluating stormwater technology. Its standardized protocol for complex testing of stormwater devices will not only save manufacturers time and money, it will produce much more reliable and accurate results in testing and provide design engineers with better data for performance evaluation. It's a change that could set the standard for other parts of the country.
What's changed and why does it matter?
- The new protocols go beyond "what" needs to be done to stipulate "how" it should be done. Stormwater device testing in controlled lab settings is a complex process, and without standard guidelines to follow, laboratories doing this testing have been using different testing methodologies. But under the new rules, all testing must now follow the same methodologies and complete the same required tests. For the first time, achieving an 80 percent removal result at one laboratory means that the same test on the same device will produce a repeatable 80 percent removal rate at another lab.
- Hydraulic requirements are now detailed and specific. Hydraulics testing has always been required, but now there are fewer gray areas about what it needs to include. The new protocols adopt professionally vetted national standards and methodology developed by the American Society for Testing and Materials (ASTM). From how often to take measurements, to which measurements to focus on, to what instruments should be used, now everything is spelled out.
- Maximum treatment flow rate will be based on scour. Performance data that includes calculations for bed scour will now set the bar for determining 100 percent storm treatment flow. Previously, 100 percent storm treatment calculations were based more on solids removal efficiency without fully accounting for impacts of the turbulence that can create movement and fluidity of the bed and allow materials to escape. This will help to more accurately predict the technology's performance in the field.
- Independent observers must now approve all in-house testing. If manufacturers are conducting in-house tests, those tests must be approved by an independent engineer who meets the state's requirements as an impartial observer. Alternately, manufacturers may outsource their testing to independent laboratories certified by the state.
It's clear that these more stringent and detailed requirements will not only level the playing field for manufacturers, but more accurately report the performance and efficiency of stormwater management devices. Design engineers will now have the reliable, proven data they need to confidently select the best value and appropriate device for their needs. As some of the most detailed and stringent stormwater testing guidelines in the nation, it offers a solid model for other jurisdictions to follow.