As a new irrigation season begins and the canal systems are once again filled with water, this is a good time to reflect on the important historical uses and future concerns of water demands in our Valley.
This year marks the 100th anniversary of the completion of Arrowrock Dam, which highlights the beginning of the practice of storing water for future land uses throughout much of the Treasure Valley.
In anticipation of Arrowrock Dam being constructed, the first water storage rights and priority dates (some refer to them as: “First in Time, First in Right”) associated with those rights were issued in 1911. In 1950, Anderson Ranch Dam became the second designated reservoir for storage rights on the river. Late in the 1950s, Luck Peak Reservoir was added primarily for flood control, although there are water users that have storage in Lucky Peak. And the fact is if the water was not stored behind these dams, this Valley’s irrigation season would end by midsummer, if not sooner.
Many people associate irrigation and our canal systems strictly with agriculture. When storage rights were first established on the Boise River, a considerable amount of water went toward the irrigation of urban properties. And, as cities have expanded over the last century, so have the number of urban acres served by irrigation districts and canal companies. As a result, the dependence urban communities have upon irrigation water and storage rights is greater than ever before.
If you receive irrigation water from an irrigation district or canal company, you likely have a vested interest in the original construction costs, and the continued maintenance of Arrowrock, Anderson Ranch and Lucky Peak dams. This is due to the storage rights that irrigation districts and canal companies hold on your behalf.
Collectively, urban water users now have a lot of skin in the water game, as well as those in the agricultural communities. This game plays into the future development of our community and the impact that growth will have on our water supply. And that poses the next question: Where will water come from for future development in the Treasure Valley? Some are suggesting it come from existing senior storage water rights!
Current and future land uses still require approximately the same volume of water per acre as historically proven. About 3-plus feet per acre per year. This is water that is already appropriated to your land. And, you own the right to the use of that water in accordance with the priority date attached to that right.
The modernization of canal systems, conservation in agriculture and implementation of pressurized irrigation in new subdivisions helps, but this is not the total answer.
We can and will continue to tap our aquifer. But, not successfully without ongoing and additional recharge with surface water application practices.
Ultimately, we know the origin of our surface and groundwater is the Boise River and our current reservoir system. Therefore we also know that any future demand for water, one way or another, will need to come from the Boise River Watershed.
Although the Boise River is fully appropriated, the river is not without additional flows and, future storage potential. Water ordinarily released for flood control could be contained and then counted toward new storage for future growth and water demand.
Any new uses need to include new appropriations. Otherwise, the alternative is the erosion of your existing water rights and priority date(s). This is something you should not allow to be taken away.