Intake Diversion Dam

Intake Diversion Dam

Background:

This 1,450 cfs (937.2 MGD, 147,814 m3/h) irrigation diversion facility located just upstream from Intake Dam diverts a significant portion of the Yellowstone River flows. The facility was required to install 1.75-mm slot size wedge wire screens with an approach velocity of 0.4 fps (12.2 cm/s) to minimize potential incidental take of federally endangered Pallid Sturgeon as well as protect many other native fish species. This project was part of a larger Yellowstone fisheries restoration effort that continues to this day.

To meet stringent fish protection requirements at the site, ISI designed and fabricated a total of 12, T78-100HA-R screen units. Each wedge wire T screen has two cylinders, each measuring 78 inches (1,981 mm) in diameter and 100-inches (2,540-mm) long. With 1.75-mm slot openings and a 50 percent open area, each screen unit is capable of providing 136 cfs (87.9 MGD; 13,864 m3/h) at a slot velocity of 0.4 fps (12.2 cm/s) and therefore provide just over 10 percent screen surface area overbuild relative to the facility capacity. The screen system includes steel retrieval tracks that are embedded within the concrete headworks to minimize potential to snag and retain debris that passes the facility in the river flow. Knife gates integrated within each retrieval track allow the facility to close off flow at individual screens prior raising them to deck level.

Benefit of ISI System

ISI's retrievable brush-cleaned cylindrical screen system was selected as the project's preferred alternative as it provided the following key advantages:

1. The on-river design keeps fish in the river rather than subject them to a fish bypass system or any type of collection or conveyance;
2. The cylindrical screen design provided the necessary screen surface area with a reduced facility footprint compared to other concepts;
3. The retrievable design allows the screens to be safely raised above the dam during the non-irrigation season when ice flows and damage potential are significant;
4. The cylindrical screens draw water from the middle of the water column where Pallid Sturgeon are less likely to be present;
5. The submerged screen design allows diversions to occur over large river stage fluctuations;
6. The retrievable screen design allows inspection and maintenance of individual screen units without shutting down the diversion facility operations.

Owner:

Lower Yellowstone Irrigation District

Engineer(s):

US Bureau of Reclamation and US Army Corps of Engineers

General Contractor:

Ames Construction

Location:

Yellowstone River, Glendive, MT