Hi lbianc1-
Congratulations on your new property and welcolme to Pond Boss!
There are two conditions that are necessary for a healthy lake; 1.Sufficient oxygen and 2.adequate mixing of the water to reduce stratification so that the oxygen is uniformly distributed throughout the water column. Dissolved oxygen is not only used by fish, vegetation, and other organisms, but it is also essential in the oxidation and bacterial digestion of suspended organic material and bottom sediments.
Under ideal conditions, natural forces can keep a lake healthy and aesthetically attractive, but unfortunately our lakes do not exist under ideal conditions. Water mixing and movement is restricted. In the summer months, hot, hazy and cloudy days worsen the situation because of lack of photosynthesis and the fact that warm water holds less oxygen. Rain and irrigation water runoff carries organic debris, nutrients and other chemicals that consume oxygen.
An effective aeration system brings oxygen into the water, eliminates stratification and increases circulation. This makes the water at all levels able to support animal and plant life, control algae growth by limiting its food source, and aid decomposition of suspended organic material and muck on the bottom of the lake.
The most efficient way to aerate is not with a fountain, but rather with a 'bottom aeration' system. Fountains are beautiful, but they will have little or no affect on the bottom of your pond.
Since you are building your pond long and narrow, make sure you consult with a profesional to design a system that takes the constraint into consideration.