There is info in the links below. You may have to be prepared to reply to there response that the bottom water is low in DO. If so you can answer by providing the you will have rocks for it to run over to add O2 and that the distance it runs will also up the O2.

Not in your area but some year round info.

http://www.pondboss.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=17;t=000064

Winter DO and temps up north

http://www.pondboss.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=11;t=000096

http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=12;t=000010#000000

http://www.pondboss.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=20;t=001610