With freezing temperatures right around the corner, we should get a respite soon from the Eurasian milfoil in the river. For us, however, a respite does not mean rest, and some of our most important work will take place in the next few months.
We have sold the undersized harvester we tried this year, and we are building plans for controlling our 11 acres of milfoil next spring. We’re studying four potential primary strategies and two additional strategies which could help around the edges. The four possible primary strategies are
- Diver-assisted suction harvesting (“DASH”), which is actually what it sounds like. Divers would use special vacuum equipment to remove the plants and their roots;
- A much larger cut-and-harvest machine, though it might have trouble reaching some spots in the river and its cost would be upwards of $500,000;
- Engaging an independent contractor to cut the milfoil as needed, with cost again being a major concern. The best price we have found is $48,000 per cutting, and we don’t yet have a firm handle on milfoil’s growth rate in this environment;
- The use of a herbicide, though there are obvious problems of efficacy in moving water and safety with Harrisonburg’s water intake being at Sandy Bottom.
The possible supplementary strategies both amount to making the river less hospitable to the plant. We could introduce enemies of the plant, such as the milfoil weevil—we kid you not—or we could try to lessen the amount of nitrogen in the stream. The weevil, however, is a rather dainty eater, and the significant sources of North River nitrogen are upstream from us.
As we evaluate what will work best, the Commonwealth is evaluating what we will be allowed to do. The Virginia Marine Resources Commission permitted our use of the undersized harvester this year, but under a law which took effect on July 1, jurisdiction may have passed to the Department of Environmental Quality. DEQ is studying the jurisdictional question right now, and we expect an answer from them late this month. We’re using the time to select our most promising control mechanism, and we will make our best pitch to either DEQ or VMRC, as the case may be. As of now, DASH appears to be the best option, because it removes the entire plant. That said, we don’t yet know the cost, and with all of these remedial measures, the more we know about them, the less we like them. We’ll keep you in the loop.
This milfoil issue is difficult in its scope, difficult in its cost, and difficult under the law, but with the help of our friends at the state level and perhaps our weevil friends, we plan to get this done.