The water rights accounting program is a set of computational tools that the watermaster uses to quantify natural flow available, natural flow use, and storage use on a daily, after-the-fact basis. The water rights accounting computes the natural flow available using streamflow, reservoir, and diversion measurements. Based on the natural flow available, the water rights accounting determines which water rights are in priority.
In Idaho, the following water districts use water rights accounting:
- Water District 01 – Upper Snake River
- Water District 11 – Bear River
- Water District 34 – Big Lost River
- Water District 63 – Boise River
- Water District 65 – Payette River & Tributes
The storage program is a separate program from the water rights accounting. There are individual storage programs for Upper Snake, Boise, and Payette reservoir systems. The purpose of the storage program is to allocate storage water to the individual spaceholders according to the federal contracts and USBR instructions. IDWR runs the storage program and USBR reviews and approves the output (storage report).