The reservoir is a storage facility of water for agriculture, municipal and recreational use. Therefore the water levels do fluctuate.  During the winter and early spring it is being filled and during the spring and summer seasons the water recedes do to increased use. Fort Collins is termed a near desert and does not receive much rainfall. It is a rare year when there is enough rain fall to add much to the storage.

The water craft found on the lake is power boats and water skis with an occasional sail boat. All boats travel in a counter clockwise direction. There are many regulations about boats and boating safety and the operators are responsible for knowing the rules.

Fishing is a very popular pastime on Horsetooth and because of the age and size of the lake there are some very large fish taken from this reservoir.  With that said the testing has found mercury in the fish here at the level of 0.5 parts per million. The government does find that you can eat small amounts of these fish without harm My advice as a nutrition researcher do not eat any food with any mercury in it. Have a zero tolerance. There is to much evidence that mercury is the most dangerous chemical found in food and water on the planet. Diseases like autism, Alzheimer's, heart disease and stroke have been found to be high risk factors. Mercury is especially dangerous to children and pregnant women.

The reservoir is part of the Big Thompson water project which brings water through a giant  pipe and pumping system from the western side of the continental divide. This tunnel and piping system gets the water from Grand Lake and is part of the Colorado River watershed. The tunnel is named the Alva B Adams Tunnel and is 13.1 miles long. The water comes out above Estes Park then to Lake Estes. Here it is released down the Big Thompson river and ends up in three different storage reservoirs one of which is Horsetooth.

Below you will find a map of horsetooth reservoir furnished by Larimer County Recreation.