Turnouts: Critical infrastructure for reliable deliveries

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CAP Turnout

We have shown many different pieces of CAP’s infrastructure – check structures, pumps, and siphons to name a few. But for water users, one of the most important pieces of CAP’s infrastructure is a turnout – the structure that facilitates water deliveries to recharge projects, agricultural districts, cities and Tribal communities.

Seventy-four turnouts have been constructed along the CAP canal, although 62 of those are currently active. And while they all “turn out” water from the CAP canal to water users’ infrastructure, they are not all identical. They have some similarities – most have a trash rack to prevent debris from entering, a slide gate or valve to control the water flow and a flow meter to measure deliveries. They also have some differences — turnouts vary in size, some use gravity while others use pumps to move the water.

However, the result is the same — water is delivered.

How? First, CAP’s Control Center operators open the slide gate, or the water user opens a downstream valve, allowing water to flow into the water user’s system. A flow meter measures the amount of water being delivered and that number is reported electronically to the Control Center where deliveries are managed. Once the correct amount of water has been delivered, the slide gate or valve is closed.

Gravity Turnout Infographic

One of the unique things about turnouts is that they are one feature that has continued to be constructed even after construction of the CAP system was declared complete in 1993. Not an easy feat when you have a canal full of water 24/7/365, so it takes collaboration from CAP and the water user. The water user, a city or water utility, hires a contractor to construct the turnout, but CAP engineers provide technical review and approval, and inspectors are on-site to oversee the work, which involves installing a coffer dam that protects the construction site from water while ensuring water continues to be delivered downstream.

Once the turnout is completed, the water user transfers ownership to CAP and we enter into a maintenance agreement, ensuring proper upkeep and operation for all portions of the turnout that are on CAP property. Infrastructure beyond our property line remains the responsibility of the water user. Finally, the infrastructure ties into CAP’s communication system so we can operate it remotely and gather data on flow, usage and slide gate status.

Turnouts are another critical piece of CAP infrastructure that ensures reliable water deliveries.

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