Changing water levels have implications for the volume of the water, obviously. So whether it's in the nearshore or on the offshore are actually two different things. I'm talking about the nearshore.
For the nearshore environment a drawdown of half a metre or a metre, when your wetland on average is only about three or four metres, means that's a quarter of the volume of water. That's a huge effect. More than that, it's not just whether it's drawn down or up, it's the fluctuations, the natural fluctuations which are very different in the Great Lakes.
In the Great Lakes, we have a 30-year cycle of up and down. People can probably remember that in the 1970s and 1980s we had very, very high waters. Then in the 1960s there were very, very low waters. It tends to cycle like that naturally.
What's happening now, which is really unusual for Lake Michigan and Lake Huron, is that it has stayed low for the last 15 years. We do have a sense that some of that is definitely because of climate change, but some of that is also because of the dredging of the St. Clair River, which has also exacerbated that.