When water comes out of your tap, you might be surprised to learn about the long journey it took to get there. Little Thompson Water District’s raw water comes from the Colorado River through the Colorado-Big Thompson Project (C-BT). The C-BT Project is Colorado’s largest transmountain diversion project, bringing water from the Colorado River on the Western Slope to the Front Range.

The C-BT Project is managed by the Northern Colorado Water Conservancy District or Northern Water. Water is collected in western slope reservoirs, transported through the Alva B. Adams Tunnel to Mary’s Lake, Lake Estes, Pinewood and Flatiron Reservoirs, and finally pumped to Carter Lake. From Carter Lake, raw water is conveyed to the Carter Lake Filter Plants for treatment.

In addition, the District maintains supplemental and emergency connections with other water supply systems and can receive supplemental water in various parts of our service area. These connections provide emergency supplies and supplemental water to boost service in remote areas of the district.

C-BT Quota

Another factor we consider each year when determining the Water Shortage Contingency Plan level is the C-BT quota. Each November, the Northern Water Board sets an initial quota for the following year and updates it in April based on snowpack. The quota is a percentage of 310,000 acre-feet, the amount of water the C-BT Project was designed to deliver each year. Learn more about the C-BT quota.

Water Storage

The District's water storage is diversified to provide both drought protection and a redundant source of storage in the event of a significant water shortage due to:

• Service interruption within the transmission system
• Flooding
• Raw water transmission issues

Northern Water's Colorado-Big Thompson Project

As a participant in the C-BT Project, LTWD has access to water in Northern Water's storage in western and eastern slope reservoirs for the current year and “carry-over” water in those same facilities for use the following year.  Learn more about Northern Water and the C-BT Project.

Dry Creek Reservoir

In 2007, LTWD and Central Weld County Water District constructed a 10,000 Acre-Foot (AF) reservoir east of Carter Lake. LTWD is entitled to ½ or 5,000 AF of storage to provide drought protection and operational flexibility. Due to the location of the reservoir and advance planning, LTWD was able to construct the reservoir without the lengthy delays and cost of federal review. The cost of the reservoir was $28 million.