h2ofwlr wrote:If I am not mistaken there is a low rise dam (keeps it up 2' higher) on Pelican @ Ashby, and why the water does not flow out of Christiana like it used to. The homeowners want a fishing type of lake that used to be more of a large duck slough/lake.
You're mistaken, partially.
Currently interest in the lake is to maximize it for waterfowl. Why the dam was put in wayyyyy back when, I don't know.
On an outflow basis the damn height/width is not congruent to the lake area. So, it can only let out so much water, regardless of what's in the lake. Think of filling a funnel too fast.
Downstream, the dam has MORE value in not fluctuating Pelican Lake's levels. The watershed for Christina is significantly larger than Pelican. By damming Christina (a portion of Pomme de Terre headwaters) it's easier to control DOWNSTREAM water levels by backing up the Christina chain (Christina, Ina, Anka). There is also a dam at the Pelican Lake Outlet, into Pelican River.
As I understand it, walleyes were introduced at some point to control minnow populations and a decent fishery developed in late '70's/early '80s, but this was an outcome, not a purpose of lake management. Like Pelican by Monticello,lots of people get mad you take their fishing hole slough away in a land of 10,000 lakes.... (I have a local story on this, but it requires beer). Somehow catching easy fish for 5 years wipes away. 100's years of history.
Heron Lake on the other hand (down by Worthington) is kept artificially high to allow ease of access according to riparian land agreements drawn up 100 years ago that provided legal definition of access and ownership to a center-point in the lake. Think of a Homeowners Association, but with a REALLY big slough as the property.