Tie Fork Beaver Dam Analogs

The Tie Fork Creek BDA site is located approximately 25 miles east of Spanish Fork City, up Spanish Fork Canyon. (See Map) Construction of a BDA • To compete construction of a BDA, 2-4” wood posts will be spaced approximately 2’ apart and positioned in a U shape, with the bend of the U located on the downstream side (See Figure 1). The number of posts needed will vary depending on the width of the creek. The BDA should span the entire creek width from one bank of the creek to the other. On larger creeks, it will require more posts to span the entire creek. 2’ of woven willow branches must be stacked on top of each other to form the dam wall. These branches should span the entire dam and go onto the sides of the bank. If willow branches are not available, other approved localized tree branch material may be used, such as pinyon and juniper branches. These should be laid across the entire width of the BDA to create the dam wall and should be 2’ tall above the stream bed. • A section of biodegradable coconut fiber approximately 4’ in width should be attached to the top of the BDA and span the length of the entire BDA. The one edge should be placed on the top of the dam wall and pushed tight against it. While the remaining material should be laid along the stream bottom so as to capture all material and prevent water from undercutting the dam and instead push water over the top of the dam. This will help catch sediment and prevent water from undercutting and flowing below the BDA. • Lastly, for the BDA to be considered complete, mud, rocks, and litter should be placed to plug holes and allow water to build up behind the dam and flow over the top center of the dam, rather than ubderbeath or the sides. Water should not be flowing around the sides or underneath the BDA. It does not need to be completely blocked off from leaking through the dam but a majority of the flow should be pouring over the center top. Once all of this is complete, the BDA is finished. Once the BDA is finished, you can count how many BDA units it took to complete it. For example, if a BDA has 5 pots spaced two feet apart and all the other materials are in place than you would have 5 BDA units. • The contract will be bid on a per BDA unit basis. The lowest cost per BDA unit will be awarded the contract. There will be a total of BDA units on this contract. • The Tie Fork Creek BDA site will have 375 BDA units (See Map)

Division 02 -	Existing Conditions, Subsurface Investigation.
Division 35 -	Waterway and Marine Construction, Dam Construction and Equipment, Auxiliary Dam Structures.