Members of the Mace  community occasionally express concerns or have questions about the impact of adjacent communities and new developments to the Mace water system. The below information is provided by people from within our community who have had extensive conversations  with experts from City of Eagle, the local Water Master, the US Army Corps of Engineers,  Idaho Fish and Game, the Idaho Department of Water Resources(IDWR)  and hydrologic engineering firms and pump companies.

 

 

As of August of 2025, there are two new developments in the planning or construction stages west of the Mace community. These developments will likely have their own pressurized irrigation and pond systems, and will need a source of water for these systems. We know the developers are in contact with IDWR  to make sure they honor water rights and to  meet legal requirements about the diversion of water for their use. We believe both developments will use a combination of ground water and a ditch called the Mace Catlin Ditch as their source of water for their irrigation and pond needs.

 

The Mace Caitlin Ditch has no bearing on the Mace River Ranch Community, confusing as the name may suggest. The Mace Caitlin Ditch water is pulled from the south channel of the Boise River.

 

The ditch Mace uses is the Mace Mace Ditch (confusing official name) which we are now calling  Mace Creek , and this water is pulled from the north channel of the Boise River. Mace Creek is indicated by the Aqua colored line on the picture; this was originally a secondary source of river water that fed into Mace Pond 6 during a part of irrigation season.

There is a third ditch we need to mention, called the Conway Hamming Ditch that draws water from the south channel. This ditch originally flowed  through the land where Island Woods subdivision was constructed, and later  was forced through a pipeline and was covered over by the Island Woods developer. This pipeline crosses under Eagle road and flows under Old Mace road to the east side of of our HOA, and became the primary source of pressurized irrigation and pond water in Mace. This Conway Hamming Ditch is illustrated on the picture, the yellow lines depicting its flow through our pond system where it leaves our HOA on the west side. 

 

Mace Subdivision’s Water Supply Project replaced the entire length of the Conway Hamming Ditch by drawing water from the north channel aquifer (not ground water) and now Mace has two separate and reliable water systems during irrigation season.

 

Ground water should have no impact on our ponds. We all  essentially live on top of a giant underwater lake (aquifer), which may be a scary thought for some.  

 

The biggest impact to our waterways is the when  the Army Corps of Engineers raise and lower  the river. As the river rises to its highest points in spring, our ponds rise as such, to the point of causing flooding in the nature preserve. As they lower it in the winter, the aquifer goes down, as do our pond levels.

 

Developer activities to our west such as  adding dirt will not impact our waterways. The impact  (and legality) of the dirt being brought to change the flood plains on the south channel, is way above any HOAs jurisdiction and there are city and legal requirements that developers need to adhere to in order to move forward as to not impact those around them. We can only assume they are following the law in accordance with the city requirements. We have to trust that process.

 

Since we live below a dam,  the risk of flooding falls on the shoulders of the Army Corps of Engineers and how they manage the river flow. A  flood of Mace could only happen if the damn operators deliberately changed the flow with the intent of flooding, or there is a  failure of a government agency or a catastrophic dam failure.

 

We were told that “snowmageddon” taught the dam operators a lot. Even during record snowfalls, our homes were still not impacted. Yet, they have changed their policies to make sure water levels don’t even hit that same mark should it happen again.