DASH: Diver-Assisted Suction Harvesting
As of September 2026: DASH is regulated under Wis. Admin. Code NR 109 as a mechanical removal method. This page summarizes current DNR guidance.
DASH is the most selective removal method available on a Wisconsin lake, and it's priced that way. A diver works underwater, hand-selecting the target plant and guiding it into a suction hose that carries it to a surface collection bag, while everything the diver doesn't touch stays exactly where it was.
How it works
DASH (diver-assisted suction)
Billed by time; roughly 200 to 600 sq ft per hour with a two-person crew
Selective enough to take invasive milfoil while leaving native plants in place.
Pros
- Very selective, removes roots
- Spares native plants
Cons
- Slow
- Costs more, billed by time
Best fit: Targeted invasive milfoil removal
A two-person crew typically runs the operation: one diver underwater identifying and pulling plants by hand, and one operator on the surface managing the suction unit and collection bags. Because the diver is choosing each plant individually, DASH can remove invasive milfoil growing mixed in with native plants without disturbing the native plants around it, something a harvester or herbicide treatment can't do.
Why it costs more per square foot
DASH is billed by time, not by acre, and typical production runs roughly 200 to 600 square feet per hour with a two-person crew, depending on plant density and water clarity. That's a small fraction of what a mechanical harvester covers in the same hour, which is the direct tradeoff for the selectivity. See the full cost comparison for how that stacks against harvesting, herbicide, and hand-pulling.
Permit requirements
DASH is a mechanical removal method under NR 109, since it uses powered suction equipment rather than a hand tool, so it needs a permit the same as a harvester or a motorized cutter does, regardless of how targeted the removal is. The small private waterbody exemption can still apply if your lake qualifies (10 acres or smaller, entirely on your property), but for most Wisconsin lakes, DASH work goes through the standard NR 109 permit process. Full logic is on the DNR permit rules page.
When DASH makes sense
- Invasive milfoil scattered through a native bed. The main use case: pulling individual invasive plants without cutting or suppressing the native plants around them.
- A defined, manageable area. A swim area, a boat lane, or a specific patch rather than an entire lake, since the per-hour rate makes large areas expensive fast.
- Sensitive habitat nearby. Where wild rice or a listed species limits other methods, DASH's precision can be the only practical option.
For a lake-wide invasive problem, mechanical harvesting or a coordinated herbicide plan usually makes more financial sense; see mechanical harvesting.
Hiring a DASH crew
Because DASH requires trained divers and specialized equipment, it's not a DIY method the way hand-pulling is. See what to ask a lake weed removal company before hiring one, including who holds the permit for the work.