Re:weed control and herbicides

[Bill Wichers <billw at waveform_net>]

> Time for some stupid questions....
>
> Being totally ignorant about algae and unwanted plants in natural waterways,
> I'm asking myself what is causing the problem in the first place. Is it
> fertilizers and other contaminants that we are dumping into the waters or
> letting leach into water ways that are the cause of these problems? Is it
> native plants/algae being introduced into eco systems where they would
> otherwise not occur naturally? I'm sure  it's not a natural occurance right?
> Is it too expensive or too late to do anything about fixing the source of
> the problem rather than resort to temporary solutions which some sound
> nearly as bad as the problem itself?
>
> Regards
> Giancarlo Podio

Probably a combination of runoff AND non-native species, but it depends on 
the local. In Michigan we have problems with milfoil, which is a non-native 
aquatic plant that looks a little bit like Cabomba. It was introduced on 
traveling (as in between waterways) small boats. We have zebra mussels too 
that are causing all kinds of problems, and they were brought here on the 
hulls and in the holds of long-distance commercial shipping.

In some cases the problem is that there are so many native plants that they 
interfere with surface craft and then you get groups that want to treat the 
water or trim or dredge. I know from experience with a local lake that the 
chemical treatments, while more effective at making the "lake look like a 
swimming pool" (these are not knowlegeable people in a lot of these 
groups), but the fish population declined. In the years when "mechanical 
deweeding" was tried (basically an underwater hedge trimmer that prunes the 
plants down several feet), the fish were much healthier but the people 
could see plants where they wanted to swim and didn't like that.

        -Bill


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