Economic considerations module: introduction | construction costs | operation and maintenance costs | safety and other liability risks | property value | recreational value | aesthetic value | ecological value | references | appendix

Construction costs

Repair

Constructions costs for the actual dam, whether they be repair or removal, will be site-specific and require the expertise of a engineering consultant. The amount of repair needed is proportional to the size and the severity of deterioration the dam has experienced over its life. The goal of any repair activity is to make the appropriate repairs to comply with safety standards. These activities may include repairing the part of the dam that spans the river, fixing abutments on the banks, and many other items.
 

Figure 1. Former Rockdale Dam shows cracks in the concrete wing walls and erosion of the spillway. (Photo courtesy of Tom Hooyer, Wisconsin Geological & Natural History Survey.)
 


A cost that must commonly be considered when repairing a dam is a fish-passage structure. Although a fish-passage structure is not always required, many times it is mandated as part of Wisconsin Department of Natural Resources regulations when repairing a dam and should be investigated as part of the repair option. Operation and maintenance are, although not directly considered in the repair cost, important considerations and are addressed later in this module. The other associated cost with repairing a dam is the liability costs that are nearly always incurred.
 


Figure 2. Main picture: Fish struggling to migrate upstream at a dam. Inset: A fish ladder. (Photo courtesy of Stephanie Lindloff, River Alliance of Wisconsin.)


It is necessary to hire an engineering consultant to estimate repair costs. The cost of the consultant should be included as part of the repair cost.

Examples: Repair

Waterworks Dam, Baraboo River, Wisconsin
3 scenarios
1) $1,091,500
• Rehabilitate
• Principal spillway (with increased capacity)
• Raceway (with in-kind overflow spillway)
• Headrace structure
•  Potter Street culverts
• Powehouse emergency overflow
• Abandon
• Turbine raceway
2) $871,000
• Rehabilitate
• Principal spillway (with increased capacity)
• Powerhouse emergency overflow
• Potter Street culverts
• Abandon
• Headrace structure
• Turbine raceway
3) $694,600
• New
• Raceway overflow spillways
• Rehabilitate
• Principal spillway (with new overflow)
• Abandon
• Headrace structure
• Raceway from Potter Street to powerhouse
Additional cost of fish-passage structure: $137,800
Oak Street Dam, Baraboo River, Wisconsin
• Estimated repair cost: at least $300,000 to meet safety standards; much more costly repairs to restore hydropower capabilities and meet FERC regulations (potentially $1,000,000+).
Deerskin Dam, Deerskin River, Wisconsin
• Estimated replacement cost: $411,000
Bloomer Dam, Duncan Creek, Wisconsin
• Estimated cost of dam rehabilitation: $1,750,000
Heyman Falls Dam, Embarrass River, Wisconsin
• Initial estimated repair costs:$650,000 - $800,000
• Second estimate: $455,000 - $763,000
Lemonweir Dam, Lemonweir River, Wisconsin
• Estimated repair cost - $700,000
Ward Paper Mill Dam, Prairie River, Wisconsin
• Estimated cost to add required gate & spillway capacity: $1.0-$1.3 million
• Estimated cost to restore hydropower and meet FERC requirements, including fish passage: $2 million (Fish passage estimated to be $400,000 of the $2 million)
 Shopiere Dam, Turtle Creek, Wisconsin
• Physically fixing dam: $251,000
• Additional costs
•  Fish-passage structure: Unspecified amount
•  Removal of trees and brush around dam: Unspecified amount
 Fulton Dam, Yahara River, Wisconsin
• Estimated repair cost - $900,000 – $1,000,000
Jefferson Dam, Rock River, Wisconsin
• “After years of trying to get help from the state, city officials finally have gotten word that they will receive financial assistance to repair the city’s aging downtown dam on the Rock River …. [T]he city had been told that it would receive matching funding from the state Department of Natural Resources this year to repair the dam …. The current dam has been in need of repair for several years, and the DNR asked the city to fix the dam in 1990 …. The cost of repairs to the dam has been estimated at $300,000 …. The DNR will match the city’s expenditures, but one question that remains unanswered is whether the agency would match money collected from private donations.” Source: Milwaukee Journal Sentinel,  6/8/97.
Rockdale Dam, Koshkonong Creek, Wisconsin
• “No buyer has come forward in the year since [the owner] put his 153-year-old dam … up for sale. [O]fficials say they are unlikely to purchase the crumbling dam ….Stopgap dam repairs alone would cost more than they’re willing to invest, and full restoration is beyond consideration, [officials] say. If a new owner doesn’t come forward … [the owner] will apply to the state … to abandon the dam. While he would have to remove it at his own expense, that wouldn’t come close to the cost of repairs or restoration …. Area residents have talked this spring of forming a lake district to share dam restoration expenses. They have discussed applying for grants. But they face some pricey hurdles …. Stopgap repairs would cost between $40,000 and $100,000 …. Full reconstruction would cost between $200,000 and $500,000. Source: The Capital Times, 6/23/99.
Billington Street Dam, Town Brook, Massachusetts
• “The cost of repairing the small earthen berm and the metal culvert that channels water under the dam is estimated to be $100,000. In general, said a state official, the average cost of small dam repair is about $200,000.” Source: The Boston Globe, 10/3/99.

Removal

The actual removal of a dam structure can be one of the easiest costs to estimate when dealing with a small dam. Usually, a community will hire an engineering consultant to estimate the removal costs. As with the repair option, the cost of a consultant should be included in the removal option. Removal usually happens by first breaching the dam in one place and slowly drawing down the impoundment. Once the impoundment is mostly drained, the actual removal of the dam itself can occur safely. Dam removal may also include the removal of complementary structures such as concrete wings that reach upstream, spillways, powerhouses, and raceways. All of these removal costs should be included as part of a consultant’s report.
 

Figure 3. Breaching and removal of the Shopiere Dam, Turtle Creek, Wisconsin. (Photo courtesy of Wisconsin Department of Natural Resources.)
 
 
Other costs are associated with sediment that has been trapped behind the dam. When the dam is removed, this sediment can be mobilized and moved downstream. A plume of sediment moving downstream may negatively impact riverine habitat. To prevent the sediment from being mobilized, part of the dam can be left in place to hold the sediment while vegetation establishes itself and acts to anchor the sediment. When the vegetation is well established, the rest of the dam can be removed. Another option for dealing with sediment is to construct a sediment trap downstream from the dam to catch silt and sand leaving the impoundment. Regardless of what measures are taken to control the impounded sediment, some will move downstream, and it may take several years before the river recovers.

Dealing with sediment movement is usually not too costly and can be easy. However, sediment impounded behind the dam can be contaminated and toxic. If this is the case, the toxic sediment will need to be isolated, removed, and disposed of before the dam can be removed. The costs of dealing with toxic sediments can be high. An engineering or consulting firm will likely be needed to help you estimate these costs.

Finally, there can be costs associated with restoration in the newly exposed impoundment. It may be necessary to seed or transplant some native types of vegetation to stabilize the impoundment. However, if the impoundment is left alone, it will “green up” surprisingly quickly from seeds stored in the sediment. Planting is only necessary if certain types of vegetation and/or land use are desired. The newly formed stream channel on the old impoundment bed may also need some type of restoration work. If the new stream banks are highly erodible, bank-stabilization measures may need to be implemented. Alternatively or in conjunction with adding riprap, the banks may need to be graded to lessen their slopes to prevent large scale erosion and cutting of the banks. Grants are available for much of the restoration work needed as the result of dam removal. (See Appendixes A and B of the Issue Identification module.)

Examples: Removal

Waterworks Dam, Baraboo River, Wisconsin
• Estimated removal cost: $216,000
• Actual final cost: $238,769 ($200,000 paid by Wisconsin Department of Natural Resources grant)
Oak Street Dam, Baraboo River, Wisconsin
• Estimated removal cost -- $60,000
• Actual final cost -- approximately $30,000 ($23,000 paid by a National Fish and Wildlife Foundation grant secured by the River Alliance of Wisconsin)
• Additional costs (not part of final cost)
• Repairs to Water Street.
•  Relocation and riprapping of storm water outfalls
•  Development of a riverwalk
Deerskin Dam, Deerskin River, Wisconsin
•  Estimated removal cost: $15,000 (could be paid by Wisconsin Department of Natural Resources abandoned dams fund)
Bloomer Dam, Duncan Creek, Wisconsin
• Estimated cost of demolition of dam: $250,000
• Grading and seeding: $200,000 (could be paid by Trout Stamp Funds through Wisconsin Department of Natural Resources)
Heyman Falls Dam, Embarrass River, Wisconsin
•  Estimated cost of removal: $272,000
Orienta Dam, Iron River, Wisconsin
• Cost of removal of two dams and disposal of concrete: $500,000 (paid by dam owner, Northern States Power)
• Additional costs
•  Bank stabilization
• Estimated cost of fish barrier to prevent upstream movement of exotics such as sea lamprey from Lake Superior: $25,000-30,000 (paid by Great Lakes Fishery Commission and Wisconsin Department of Natural Resources)
Lemonweir Dam, Lemonweir River, Wisconsin
• Final removal cost: $190,000
Ward Paper Mill Dam, Prairie River, Wisconsin
• Estimated cost of total removal of dam structure: $95,000
• Estimated cost of removal of spillway and gates, leave abutments and piers for “bridge” for railroad spur: $200,000
• Actual cost: $300,000 for total removal after initially attempting to keep bridge, but decided the structure was too deteriorated (paid by dam owner, International Paper Company)
Shopiere Dam, Turtle Creek, Wisconsin
• Actual estimated removal cost: less than $100,000
• Likely all funded by Wisconsin Department of Natural Resources grant because it was ownerless
• Additional costs(part of estimated total cost)
• Upstream and downstream restoration
•  1 acre of grading to lessen bank slope in some areas of impoundment (bank-stabilization)
Fulton Dam, Yahara River, Wisconsin
• Final removal cost: $375,784 (50% paid by state of Wisconsin)

 

Next section: Operation and maintenance costs

URL: http://www.ies.wisc.edu/research/wrm00/econcon.htm