Irrigation Diversion Blocks

The Gallatin Conservation District currently has concrete irrigation diversion blocks available for purchase. The blocks are the size of 6’ x 3’ x 3’ and weigh approximately 2200 lbs.

The cost per block is $150.00. If our inventory is low, please allow 2-6 weeks (depending on quantity) to pick up blocks. Blocks are located near Belgrade. To purchase the blocks contact:

Gallatin Conservation District    
PO Box 569
Manhattan, MT  59741
Phone/Fax:  (406) 282-4350

There will be personnel available to assist in evaluating locations for the suitability of these blocks if needed.

Informative Article

A new irrigation diversion system using portable concrete blocks has been developed by the Department of Natural Resources and Conservation (DNRC). A 223 Grant was initially acquired by the Gallatin  Conservation District to construct two steel concrete forms capable of building a wide variety of block sizes and purchased 18 concrete blocks to build a diversion on the Gallatin River at Logan.

The concrete blocks are relatively inexpensive, very durable, and can be loaded onto the streambed rapidly. A chain is hooked onto exposed rebar at the top of the blocks for lifting. The blocks are set directly on the stream bed and have sufficient weight to provide a stable dam. The blocks are set on the streambed, after spring runoff, to allow the stream to freely flush gravel bed-load and debris through the diversion site. The concrete block diversion is typically built as a wing dam and excess flows go around the upstream end of the diversion rather than overtopping the blocks. The blocks are removed at the end of the irrigation season and stored on the stream-bank, out of the riparian zone.

The concrete block diversion was designed to provide an environmentally friendly alternative to traditional diversion methods of using permanent dams constructed with large rock or temporary dams constructed with river gravels. The only permit required for this diversion would be a 310 permit (or 10 year annual maintenance permit from the local Conservation District. Technical assistance is available from DNRC for design and installation of new concrete block diversions.