Dam Abandonment - Oak Street Dam, Baraboo, WI

1. General Description (brief overview)

The removal of an aging hydroelectric dam from the Baraboo River. The dam is in disrepair, unsound structurally, and has failed a departmental dam safety inspection. The dam removal involves a real estate transaction involving the Department of Natural Resources, the current owner of the dam, the City of Baraboo, and other private parties. The Department of Natural Resources will purchase the dam spillway, the City of Baraboo will purchase a parcel of land that includes the power canal, and others will purchase the remaining structures. The Department of Natural Resources will remove the spillway. The parcel with the power canal will be developed into a section to a walking trail along the river, and the remaining real estate will likely be developed for commercial purposes.

2. Purpose and Need (include history and background as appropriate)

 The purpose of this project is to remove an aging structure from the Baraboo River and restore natural river processes including sediment transport, and deposition, scouring, and maintenance of riffle, pool, run, riverine habitats. Removal will alleviate any liability concerns regarding dam failure. The removal will re-establish a rocky riverbed well suited for spawning and provide for fish passage where populations were once isolated. The removal will also make a section of the river more accessible for canoeing.

 A Corps of Engineers inspection report (1980) states that the dam was originally constructed in 1860 of timber and rock. The dam was used to generate power a flour mill and for a towel mill factory beginning in 1910. In 1922, modifications of the flume were completed to transform the dam to hydroelectric power generation.

 The present concrete dam was built in 1929, and it was built on the downstream face of the old timer crib dam. The downstream apron was constructed to its present dimensions in 1940.

 The McArthur family has owned the dam since 1898, and the current owner is Steven McArthur of Baraboo. Mr. McArthur also owns the Linen Mill Dam on the Baraboo River located approximately 1.5 miles downstream of the Oak Street Dam. Mr. McArthur has granted an option to the Department of Natural Resources to purchase the dam spillways for both Oak Street and Linen Mill. Both spillways will eventually be removed, but the Linen Mill spillway is not scheduled for removal until after September 1, 2002. The Oak Street project will occur after all procedural requirements are fulfilled.

3. Authorities and Approvals (list local, state and federal permits or approvals required)

Wisconsin Department of Natural Resources - Chapter 31 Manual Code Approval

 US Army Corps of Engineers

 City of Baraboo

4. Estimated Cost and Funding Source

 Cost of removal (separate from the purchasing costs) is estimated at $90,000 (DNR estimate stated by Sara Johnson in a River Alliance of Wisconsin letter to the National Fish and Wildlife Foundation, August 15, 1996). Funds for the project will come from state, federal, and private non-profit sources agencies and organizations.

5. Manipulation of Terrestrial Resources (include relevant quantities - sq. ft., cu. yard., etc.)

 Coal tar contaminated sediment must be removed from the millpond as part of the dam removal. The contaminated sediment originated from a coal gas plant, located on the south bank of the river, that operated during the late 1800s to the early 1900s. In the early 19000s, Alliant Utilities purchased the property where the plant was located. The project will begin with clearing a south bank (of the millpond) area and installation of a sheet pile and rock coffer dam around the contaminated sediment. With the sheet pile coffer dam in place, the dam removal contractor will begin a breach of the spillway, at the north end, and a slow drawdown of the mill pond. Coal tar sediment will be removed from within the coffer dam and disposed of according to the work plan, "Attachment O." The north end of the spillway will be removed during the sediment removal, and concrete and rock will be used to fill in the power canal. After sediment removal is complete, the cofferdam and the south portion of the spillway will be removed and excess material (clean material) will fill the headrace. The upstream and downstream banks will also be lined with excess material (rock riprap and clean fill) Power lines will be relocated, disturbed banks will be shaped, topdressed, and seeded, and a portion of the sheet pile coffer dam will remain on the south bank upstream of the spillway. The toe of the sheet piling will be lined with riprap for scour protection, habitat and esthetics.

 A hydraulic hammer mounted on a backhoe will be used for demolition work. Excavation and grading activity will also occur. A drag line may be used for removing sediment, and special containers will be used to store coal tar sediments. Carriage water from the coal tar sediments will be handled according to the sediment removal workplan. Explosives may be necessary to remove concrete below the bed of the river.

 The clean silty material, if removed, will be incorporated into the site restoration. Excess material will be trucked off site for disposal at an appropriate location. Clean fill (sediment) may be placed in the power channel at the former Waterworks Dam. The City of Baraboo, Water Department, is willing to except excess material.

 Other changes to terrestrial resources involve improvements to streets, buildings, and construction of a trail, and they are described in item #7 below.

6. Manipulation of Aquatic Resources (include relevant quantities - cfs., acre feet, MGD, etc.)

 The dam has created an impoundment of 64 - 195 acre-feet, surface area of 16 - 38 acres and a length of 0.8 miles. The mill pond will be eliminated and the river channel restored to pre-dam dimensions. A steep river gradient is present at the dam site, and water will move through the area at a velocity higher than most area along the river. Soundings indicate that the bed in the mill pond is made up of coarse gravel, cobble, and large boulders, along with silt deposits. A large riffle or rapid complex will be present in areas directly upstream of the spillway. This complex will provide excellent habitat and water quality for aquatic species.

 The raceway/power channel is an excavated lined channel about 300 lin. ft. and 28' - 26' wide which leads to the powerhouse. It has poor overall water quality, even though residence time is short. Sediment buildups occur, and habitat values are limited. The power channel will be filled and completely eliminated.

7. Buildings, Treatment Units, Roads and Other Structures (include size of facilities, road miles, etc.)

 The dam spillway is a timber crib structure covered with concrete. The concrete spillway 207.5' long and, ii is uncontrolled (i.e. without gates). The top width, of the spillway, is 2.7' with an 18' wide apron. The structural height, of the dam, is 12.4' with a head of 8.0' at the powerhouse.

 The excavated raceway which begins 50' from the dam on the left bank facing downstream and re-enters the river about 250' downstream from the dam. Outlet capacity of the powerhouse is 144 cfs. The power house contains a 130 HP turbine. Water Street passes over the raceway/power channel at the headrace and just before entry into the powerhouse.

 The powerhouse is part of a building complex (all connected) that houses local businesses.

 Changes to building structures and roads that will occur from this project are as follows:

•  The back wall of the powerhouse will be altered and the tailrace may be filled per arrangements with the current property owner(s).
•  The headrace/power canal will be filled, and street repairs to Water Street will occur.
•  The dam spillway will be removed.
•  A riverway trail and information kiosk on the history of the Baraboo dams may be constructed (see recommendations in Attachment N) on property acquired by the city from the dam owner.

8. Emissions and Discharges (include relevant characteristics and quantities)

 Though precautions will be taken, silt will be lost downstream. Exhaust and noise from the removal equipment will occur.

 Alliant Energy has a groundwater contamination site on their property located across the river (the south or right bank facing downstream) from the spillway. Also, coal tar contaminated sediment, from the same property, is located on the river bed. The influence of the dam has increased the elevation of the groundwater at the Alliant groundwater contamination site. The groundwater table gradient will become steeper, and the elevation of the water table will be lower after removal of the dam. The remediation effort will not be comprised, but the remediation methodology and plan may need to be modified. As mentioned in item #5 coal tar contaminated sediment will be removed from the river bed and a sheet pile wall along a bank area will contain additional below ground surface contamination on the Alliant property.

9. Other Changes

 The removal of the dam will re-establish the natural river gradient. The river will be shallower, flow faster, and expose rock characteristic of the area at the time when this area was known as the Baraboo Rapids.

 The rapids area will provide excellent spawning habitat. The dam has flooded the area and impeded fish passage. Various fish species which were absent from the area will be able to utilize the area once the dam is removed.

10. Identify the maps, plans and other descriptive material attached

 Attachment A County map showing the general area of the project

 Attachment B USGS topographic map

 Attachment C Site development plan

 Attachment D DNR county wetlands map

 Attachment E Soils map

 Attachment F Photos (with plan showing photo points)

 Attachment G Floodplain map

 Attachment H FERC letter of jurisdiction

 Attachment I Survey of fishery (summary)

 Attachment J Letter from Rich Vogt to Steve McArthur

 Attachment K Stimulation of river with dam removed

 Attachment L Option to purchase

 Attachment M Transfer of dam ownership

 Attachment  N Cultural Resources Analysis

 Attachment  O Sediment Remedial Action Plan.

 Information Based On (check all that apply):

 [x] Literature/correspondence (specify major sources)

 [x] Personal Contacts (list in item 28)

  Field Analysis By: [x] Author [x] Other (list in item 28)

  Past Experience With Site By: [ ] Other (list in item 28)

11. Physical (topography - soils - water - air)

 The riparian corridor is the primary area affected by the project. Excavation, grading, filling, and slope stabilization are the primary activities that will affect the physical environment. Street repairs and improvements will also take place in order to make the waterfront area more attractive

 The dam removal will affect the riparian corridor and the aquatic system within the project area. Water depth will be lowered by 4 to 6'in the river upstream of the dam. The existing raceway system will be eliminated, and all river flow will be returned to the main channel of the river. Some release of sediment downstream is expected, but sediment removal and management will reduce the volume of sediment released to downstream areas. The riverbed structure above the dam will change. Fine silty material will be replaced with medium to coarse grained sands with areas of gravel, cobble, and possibly boulder.

 The river bed and bank areas at the dam site and headrace will be affected by the removal. The headrace will be removed, and the bank area at the intake to the headrace must be restored via grading, filling, and slope stabilization. The bank areas at the abutments of the dam will require shaping and stabilization. A section of sheet piling will remain along the south bank on the Alliant Energy property. Rock riprap will be placed at the toe of the sheet piling to provide fish habitat and to create a more natural looking bank area.

 The raceway or channel to the powerhouse will be filled as part of the dam removal. The existing raceway is about 500' in length with an average width of 27'. The depth of the channel is between 4' and 6'. The side slopes along the channel are steep but relatively stable.

 Water flows through the raceway and returns to the river at the powerhouse. The City proposes to fill the raceway to the surrounding grade, place topsoil, seed and mulch the area.

 The discharge from the powerhouse to the river will be eliminated. The tailwater area below the powerhouse may be filled, and the natural bank configuration will be established. Aeration and mixing occur in the river at this location.

12. Biological (dominant aquatic and terrestrial plant and animal species and habitats including threatened/endangered species; wetland amounts, types and hydraulic value)

 The riparian corridor along the Baraboo River is the dominant natural feature within the project area. An island is located in the river channel below the dam. The river banks are approximately 15' high along much of the river channel within the project boundary.

 The dominant vegetation communities/habitat types present in the project are floodplain area, and the river channel and banks.

 The McHenry - St. Charles Association are the dominant soil type on the upland areas outside of the floodway and floodplain. These soils are well-drained, moderately permeable soils on till plains and moraines. These soils formed in loose loamy glacial till and are underlain by gravely sandy loam glacial till.

 Soils in the floodplain riparian corridor are level poorly drained fluvaquents. Most of the areas are long and narrow with a wide range of soil characteristics. Surface layers range from silt loam to sand to organic. Hydric units including Adrian, Houghton, Marshan, and Palms are found within this mapping series. Permeability of the Fluvaquent unit is moderate to high, but frequent flooding and a higher water table keep the soils wet. Woodland habitat within the unit is fair, and wetland habitat is good.

 Dominant species types among the vegetation communities are as follows:

•   Slopes to river: Southern mesic forest type at the top of the river bank. The dominant tree types are Black Walnut, Oaks (Quercus sp.), and Black Locust (Robinia pseudoacacia).
•  Floodplain: Tree types include silver maple (Acer Saccharum), box elder (Acer negundo), black willow (Salix nigra), American elm (Ulmus americana), mulberry. The shrub sapling stratum includes honeysuckle (Lonicera sp), Virginia creeper, sumac, wild grape and dogwood. The dominant herbaceous species include reed canary grass (Phalaris sp), smooth brome grass (Bromus sp), Kentucky blue grass (Poa sp), goldenrods (solidago sp), ragweed, and wild mullet.
•   The vegetarian communities along the river channel and banks are virtually identical to the floodplain/floodway community.

There are no Endangered, Threatened, or Special Concern species present within the terrestrial and aquatic plant and animal communities at this project location.

13. Cultural

 a. Land use (dominant features and uses including zoning if applicable)

  The City of Baraboo is located in the east-central portion of Sauk County in south-central Wisconsin. Land in Sauk County is used mainly for agriculture. However, the Cities of Baraboo, Reedsburg, Lake Delton, and Sauk-Prairie are growing commercial centers. About 75% of the land area is used for crops and pasture, 15% contains woodlands and wetlands, and less than 7.5% is devoted to homes, roads, industrial, and commercial use. Much of the woodland is concentrated in the Baraboo Range.

  The Oak Street Dam is located within a few blocks of downtown Baraboo between the Broadway and Walnut Street bridges. Land use is commercial, light industrial, and residential on both the north and south sides of the river at the dam site. Circus World Museum is located approximately 3 mile downstream of the dam site. Devil's Lake State Park is located within 3 to 5 miles of the dam site.

 b. Social/Economic (include ethnic and cultural groups)

  The 1990 population of Sauk County was 46,975. Baraboo is the largest city in the County with a population of 9,203 (1990). Baraboo and Reedsburg are service centers for the surrounding area. The Baraboo industrial park has several manufacturing facilities including food distribution, printing, and plastics production. Circus Word Museum is an important tourist and cultural attraction in Baraboo. The University of Wisconsin system has a campus in the city.

 c. Archaeological/Historical

  Based on previously archaeological surveys of the area, it is unlikely that any archaeological sites are present.

  The winter quarters of the Ringling Circus or "Ringlingville" is a historic landmark of national significance. It is located approximately 3 mile from the Oak Street dam.

  The waterworks historic district that includes parts of the waterworks dam is located approximately 1 to 1.5 miles downstream of the Oak Street dam. The waterworks dam was removed during the winter of 1997-98.

  The Oak Street dam was originally a timber crib structure that was built in 1860. A turbine was installed in 1908 and replaced with a larger unit in 1922. Major improvements took place in 1929, 1936, 1940, and 1980. As with many old dams, the existing dam and appurtenances are substantially different from the original timber crib structure.

  The dams in Baraboo have cultural and historical significance, but the river in a free-flowing state is also very much a part of the history of the area. As it flows through the City, the Baraboo River is unique to the southern half of the state due to its steep gradient and rocky bottom. Historical accounts refer to this stretch of the river as the "Baraboo Rapids."

14. Other Special Resources (e.g., State Natural Areas, prime agricultural lands)

 There are no prime agricultural lands in the vicinity of the dam. Devil's Lake State Park and the Ice Age National Scientific Reserve are the most important natural features in the area. The park includes 9,000 acres of land and a 373-acre seepage type lake. Devil's Lake State Park is one of the most popular parts in the state's park system.

15. Physical (include visual if applicable)

 The river channel and riparian corridor will change with the removal of the Oak Street dam. The water levels above the dam will be lowered to the pre-dam condition. All river flow will be contained in the existing river channel with elimination of the power channel. Higher water velocity will move bed material downstream and create a more complex river bed condition. Cobble, boulder, and sand and gravel substrate will redevelop and improve habitat and food web complexity. Some fine material will be moved downstream, and some material may need to be removed from the flowage bed. A slow drawdown and inspection will determine the need for dredging. Proper sediment management will be a key element in the removal process.

 After complete drawdown, mud flats will appear along the river edges. These exposed areas will "green up" rapidly because of abundant moisture and soil fertility. Landscaping may be necessary after areas dry out. Bank structure along the river will be affected with the dam removal. Stabilization measures including grading, shaping, riprap, and seeding may be necessary. Stormwater outfalls will need to be extended and riprap aprons installed if necessary.

 The power channel will be closed off and filled, and improvements will be made to Water Street. A bike/walking trail is proposed to pass by the dam site. Active discussion has occurred about building an interpretive display on the history of the dams in Baraboo at the Oak Street site.

16. Biological (include impacts to threatened/endangered species)

 The dam site after removal will have higher water velocities, more aeration, and a more diverse river bed structure. In the fishery and aquatic insect populations improvements will occur in species diversity and abundance. Removal of the dam will eliminate another barrier to fish movement and habitat fragmentation. The increase in rock substrate, riffle type habitat, now submerged, will provide spawning habitat for several fish species including forage fish and aquatic organisms. Rock substrate is a significant component of a healthy river ecosystem.

The Linen Mill Dam (downstream) is often submerged during higher flows, and fish species may be able to migrate unimpeded from the lower to the upper Baraboo system during these periods.

The surface Water area of the mill pond is frozen during the winter months. Open water areas will extend to the upper reaches of the former mill pond after the dam is removed. A larger expanse of open water will provide additional winter habitat for bald eagles, and other bird life that reside along riparian corridors during winter.

17. Cultural

 a. Land Use (include indirect and secondary impacts)

 The City of Baraboo has actively planned to develop the river front area at the Oak Street dam for recreational purposes, and improvements to streets and conversion of the power channel to other uses (i.e., open space for an interpretive display or park) and will enhance the Water Street area.

 Removal of the dam will increase the opportunity for canoeing on the river through the city. The bike\walking trail proposed for the area will create opportunities to enjoy the river setting and wildlife along the corridor.

 The removal of the Oak Street Dam will lower the regional flood elevation and remove some areas from the floodplain.

 b. Social/Economic (include ethnic and cultural groups, and zoning if applicable)

 Mill dam sites often have nostalgic appeal to local citizens. They become a part of the landscape, and sentimental attachment is often quite strong. However, the loss to the community can be mitigated if the dam site is properly restored after removal. It is also important and necessary to enhance or make better elements of public rights (i.e., habitat and water quality and recreation) at sites where a dam is removed.

 Floodplain zoning will no longer affect some of the properties upstream of the dam due to the reduction in the regional flood elevation.

 Street repairs at the dam site can move forward with the removal of the dam and a refurbished Water Street area may facilitate a resurgence of economic activity.

 c. Archaeological/Historical

 There are no intact archaeological sites are present at the dam site.

 The dam site is not with the National Historic Landmark associated with the Circus World Museum property. No impacts will occur to this landmark including visual impacts.

A thorough analysis of archaeological/historical resources is included in Attachment N (Cultural Resources Analysis). The recommendations in this report support the idea that the historical significance of this property can be documented through an interpretive exhibit.

18. Other Special Resources (e.g., State Natural Areas, prime agricultural lands)

 Agricultural lands will not be affected by the removal of the Oak Street dam. Water Street passes over the power channel, and the street is in need of repairs. The City is reluctant to begin street repairs until the dam is removed. Commercial interests should benefit from the street repairs. They should also benefit from the proposed bike/walking trail along the river at the dam site.

19. Summary of Adverse Impacts That Cannot Be Avoided (more fully discussed in 15 through 18)

 Unavoidable adverse impacts are as follows:

•  Some degree of sediment transport.
•  Loss of low quality aquatic habitat when the power channel is filled.
• Creation of temporary unvegetated areas when the submerged stream channel is exposed from the drawdown.
• Loss of the dam site as a symbol representing the cultural and economic development of the City of Baraboo.
• Temporary disruption of traffic and congestion along Water Street during removal of the dam.
•  Noise and disturbance associated with the operation of construction equipment.

20. Identify, describe and discuss feasible alternatives to the proposed action and their impacts. Give particular attention to alternatives which might avoid some or all adverse environmental effects.

No action - The dam will continue to deteriorate, and it is subject to inspection and repairs to assure that it complies with NR 333 of the Wisconsin Administrative Code. With the recent change in ownership, the dam will not function for hydropower generation. The previous owner was in the early stages of licensing through the Federal Energy Regulatory Commission (FERC). The Department of Natural Resources took a position during the process that fish passage would be necessary if the dam were to be licensed by FERC. Fish passage would be a costly improvement, and the previous owner has decided to not go through the licensing process.

  Enlarge the scope of the project - Enlargement of the scope of this project would include removal of the Linen Mill Dam located downstream of the Oak Street Dam. Extensive habitat improvements would occur both upstream and downstream of the Oak Street Dam, and these would include, but not be limited to, bank shaping and riprap, placement of rock for spawning substrate, installation of structures to increase scour and direct current, and specialized planting to increase shore cover. Improvements to stormwater routing that would minimize the adverse affects of urban stormwater are also possible.

 Reduce the scope of the project - The spillway could be removed or breached (only), and the power channel could remain in place. The urban river tail could be eliminated from the project. The information display could also be eliminated.

  The "No Action" alternative is counter to the goal of restoring a free flowing river through the City of Baraboo. Opportunities to restore habitat and improve water quality would be lost. The City of Baraboo would be faced with higher costs for street repairs if the power channel remains. The Department of Natural Resources will be faced with repairs for the dam that provides very little if no benefit to aquatic resources.

Enlarge the scope of the project to include removal of another dam and habitat work along the river. This alternative is in line with the Department's long-term goal for improvements to the Baraboo River system. Negotiations are in progress to acquire the Linen Mill Dam by the Department, and the Department is pursuing federal funding for habitat work on the reach of the river through the City of Baraboo.

Reduce the scope of the project to removal or breaching the spillway only. This alternative is not at all feasible because it is not at all in line with the Department's goals for the river system. Street repairs along Water Street will be more costly to the City of Baraboo, and the City will own a power channel that is of no use. The proposed river tail is an important part of the City's effort to beautify the Water Street area and make it more attractive to commercial and recreational uses. Elimination of the trail would be contrary to the City's goal for the river at the site.

The historical significance of the dam and the Waterworks Dam will need to be documented. The Oak Street site is an obvious choice for the interpretive exhibit. An exhibit is in keeping with the City's goal to improve the Water Street area for recreation, and the space is available for an exhibit after the power channel is filled. Finally, breaching the spillway or removal of only portions of the dam would not release the new owners from liability (Section 31.18, Wis. Stats.).

The project as proposed is the most attractive alternative to the Department, the City of Baraboo, and the former owner of the dam. Also, the project as proposed is in keeping with the long-range goal to remove the Linen Mill Dam and complete major habitat work on the Baraboo River system. This alternative has substantial benefits with very little in the way of adverse affects.

21. Significance of Environmental Effects

a. Would the proposed project or related activities substantially change the quality of the environment (physical, biological, socio-economic)? Explain.

Removal of the Oak Street Dam will change the physical, biological, and socio-economic factors associated with the quality of the environment. However, there will be no net losses in the quality of the environment. An unimpeded riverine condition will enhance natural resource values and provide water based recreational opportunities for the public.

b.  Discuss the significance of short-term and long-term environmental effects of the proposed project including secondary effects; particularly to geographically scarce resources such as historic or cultural resources, scenic and recreational resources, prime agricultural lands, threatened or endangered species or ecologically sensitive areas. (The reversibility of an action affects the extent or degree of impact)

 There are no geographically scarce resources, scenic, prime agricultural land, or threatened or endangered resources that will be affected by this project.

22. Significance of Cumulative Effects.

 Discuss the significance of reasonably anticipated cumulative effects on the environment. Consider cumulative effects from repeated projects of the same type. What is the likelihood that similar projects would be repeated? Would the cumulative effects be more severe or substantially change the quality of the environment? Include other activities planned or proposed in the area that would compound effects on the environment.

Similar dam abandonment and removal projects will be repeated. Many dams that were constructed for logging and military purposes and converted to electric power generation are deteriorating. Recreational and wildlife habitat values associated with millponds have deteriorated from sediment loading and poor water quality. Dam removal is a cost-effective option compared to repair when natural resource values and recreational benefits to the public are considered. Removal of the Linen Mill Dam (downstream) is planned to occur within 3 to 5 years or less.

Cumulative effects of dam removal will have no negative impact on the quality of the environment. The cumulative effects of dam removal will improve the quality of the environment. Site specific and temporary disturbances to aquatic and terrestrial resources will occur. However, long-term cumulative effects from dam removal can result in a net increase in bio-diversity in aquatic systems. Cumulative effects of dam removal can improve conditions for rare and endangered species that have been effected by aquatic habitat fragmentation. In the Baraboo River, the aquatic environment will improve, and the effects of habitat fragmentation will be reversed when the Oak Street and Linen Mill Dams are removed.

23. Significance of Risk

a. Explain the significance of any unknowns, which create substantial uncertainty in predicting effects on the quality of the environment. What additional studies or analyses would eliminate or reduce these unknowns? Explain why these studies were not done.

There are no significant unknowns associated with this project. The results of dam removals are highly predictable. Pre-dam hydrology and stream morphology is restored. Hundreds of dams have been removed in the State of Wisconsin within the regulatory guidelines in Chapter 31 of the Wisconsin Statutes.

b. Explain the environmental significance of reasonably anticipated operating problems such as malfunctions, spills, fires, or other hazards (particularly those relating to health or safety). Consider reasonable detection and emergency response, and discuss the potential for these hazards.

Sediment transport, contamination in sediments, and erosion from earthwork are the major risks during dam removal. Best Management Practices for construction site erosion control will be required in the approval to remove the Oak Street Dam. Sediment loss will be reduced with a breach, slow drawdown, and a coffer dam to contain coal tar contaminated sediments. After drawdown is complete, the bed condition in the mill pond will be assessed to determine the need for dredging along with the removal of contaminated sediment.

Coal tar sediments contain Polyaromatic hydrocarbons or PAHs. These compounds include both known and suspected carcinogens. The health risks associated with these compounds are primarily linked to direct skin contact or inhalation. A work plan, to remove coal tar sediments, has been developed by DNR staff, Alliant Energy and their consultant. The work plan is described in Attachment O. and, it has been developed in a manner to reduce human exposure (with the contaminants) by both skin contact and inhalation. Through the plan, contaminated sediment will be isolated and contained, removed from the riverbed, stored and dewatered, and disposed of in using environmentally sound practices and in compliance solid and hazardous waste regulations.

Incidental spills of petroleum products are a risk at any construction site where heavy equipment is in operation. Contingency plans for spill containment and cleanup will be included in the bid specifications and contract for the removal.

24. Significance of Precedent

a. Would a decision on this proposal influence future decisions or foreclose options that may additionally affect the quality of the environment? Explain the significance.

Removal of this dam will demonstrate that there are alternatives to repair and maintenance of aging dam structures. Removal of this dam will improve aquatic habitat and protect public rights in navigable waters.

b. Describe any conflicts the proposal has with plans or policy of local, state or federal agencies that provide for the protection of the environment. Explain the significance.

 Removal of the dam is in line with the City of Baraboo's efforts to improve waterfront areas. The project is eligible for a GP-1, a simplified permit process, through the Corps of Engineers. The removal is very much in keeping with effort by the Department of Natural Resources to improve habitat and water quality in the Baraboo River.

 The Baraboo River 100-year floodplain will need to be modified to reflect the river profiles without the dam.

25. Discuss the effects on the quality of the environment, including socio-economic effects, that are (or are likely to be) highly controversial, and summarize the controversy.

Local opposition to dam removal is quite common. Often dam structures and mill ponds represent a "desirable" condition to local residents. Past experiences demonstrate (i.e., removal of the Waterworks Dam) that the level of acceptance increases as dam sites return to pre-dam conditions.

26. Explain other factors that should be considered in determining the significance of the proposal.

 None.

27. Summarize citizen and agency involvement activities (completed and proposed).

August 1991 - previous owner (McArthur) notified by FERC that the dam needs to be licensed.

December 1994 - Baraboo River Survey by Tim Larson (Fisheries Biologist)

June 1997 - The DNR, through conference call, states position that the agency would like to see the dam removed.

June 1997 to June 1998 - Negotiations between previous owner, DNR, and the City of Baraboo on options to buy portions of the Oak Street Dam.

June 1, 1998 - Option granted for DNR and the City of Baraboo to purchase portions of the dam for removal.

October 1998 - DNR staff discover coal tar sediments.

November 1999 - DNR staff meet with Alliant Energy about coal  tar sediment agrees to address the problem

December 15, 1998 - DNR approves of Transfer of Ownership for the Oak Street Dam.

May 7, 1999 - Meeting DNR staff including Archaeologist Victoria Durst, and City of Baraboo to discuss Cultural Resources Analysis.

June 29, 1999 - Meeting between DNR staff and Alliant Energy and their consultant to discuss a work plan to remove coal tar sediments.

August 3, 1999- Cultural Resources Analysis completed and sent to Environmental Analysis and Review Specialist

 August 3, 1999 - Work plan for removal of coal tar sediments approved.

 Signature of Evaluator Date Signed

 Noted: Area Director or Bureau Director Date Signed

Copy of news release or other notice attached? [ ] Yes [ ] No

Number of responses to public notice

Public response log attached? [ ] Yes [ ] No