What are the benefits to the City if the dam remains (not in order):

-          Enhance attractiveness of Island Park & maintain Windom town heritage -- need to preserve every benefit it has going for it

-          Preserve pond environment – slow down flow of water, minimize water level fluctuations and minimize erosion in reservoir

-          Restore a premier migratory bird habitat – attraction to the city

-          Restore fish friendly body of water that includes fish passage provisions (DNR concern)

-          Preserves the potential for an enhanced bird habitat by creating a linear island with 4 shorelines

-          Preserves the potential for a unique trail system using the island which could connect with the land using pedestrian bridges and interconnect with a trail system building from Jackson to Kilen Wood State Park

-          Eliminate confrontational property-taking issues should such a trail system be built later along the river                 through a nasty condemnation process

-          Slowed down water flow helps protect ballfield investment – minimize damage of faster flowing water

-          Minimizing water level fluctuations  helps reduce associated water table fluctuations in the Rolling Green and Remick Ridge hillside areas – promotes long term stability in areas with shallow groundwater

-          Slower, evened out water flow promotes thicker ice for safer winter sports and kids

-          Reduces erosive risks of faster flowing floodwaters to public and private property

-          Reduced liability risks to city, if city actions would otherwise cause damage to property

-          Eliminate potential risks to sanitary sewer and water lines adjacent to Highway 62 bridge

-          Eliminates new risks to bridges – discuss with MnDOT 

-          Eliminates fire risks associated with dry vegetation adjacent to landowners

-          Eliminates pockets of stagnant boggy ground – mosquito habitat

-          Attractive feature to draw people to Windom and reconnect with the river and nature

 

Phase 1:             Dam Restoration

-          Verify soil conditions in abutment area as needed.

-          Riprap retrofit downstream face of dam, sufficient height to breakup hydraulic roller effect unless aesthetic concerns indicate a full height retrofit was appropriate.

-          Rehab / modify wingwalls as needed – sawing, shotcrete, etc.

-          Utilize existing concrete “riprap” as base of additional riprap; suggest Sioux Red Quartzite as source of riprap (durable, attractive, local quarry is north of Windom).

-          Widen dam using riprap will also establish fish connectivity and maintain pool height at existing dam crest elevation, use this new flow area for fishing pools.

-          Above would serve as basis to revitalize the Island Park area and help turn this specific area into a key attraction for the City.

-          Also map sediment in basin, using historic aerial photos to help reliably establish what is actually there

             (Cottonwood SWCS has previously indicated watershed erosion control efforts are paying off;

             farmfield deep drain tiling also significantly reduces erosion from tilled fields).

-          Work with above information, develop conceptual plans for linear island concept,also  consider stilling basin or submerged check dam concepts as a control to deposit future sedimentation at a convenient location.

-          Some material may be removed; some or all may actually be reshaped in the river itself and left in the reservoir.

-          This Phase 1 scope of work is a “standalone” project to restore river  to an enhanced version of the status quo with public and environmental benefits.

 

Phase 2:         Reservoir Island Earthwork

-          Develop and implement the above conceptual plan for a linear island concept, considering the following factors:

-          acceptability of sedimentation for on land farmland disposal (sediment sampling needed);

-          location and haul to farmland for a dewatering basin (as was done at Sleepy Eye by Mathiowetz Construction);

-          if appropriate, temporarily remove a portion of the “fish passage” riprap dam to lower the water levels sufficient to allow scraper hauling of any removed dredging (most economical);   or just use a small dredge as per Sleepy Eye’s project  (ideal water depth for migratory birds = 4 feet?);

-          assess feasibility of check dam/stilling basin concepts to manage future sedimentation;

-          optimally design channels and island to maximize low flow volume water velocities to best resemble “natural” river channels – improves downstream water quality;

-          above efforts would appear ideal for state wetlands restoration statewide tax funding if it passes;

-          should discuss with US Army Corps of Engineers since they are faced with these same issues on a larger scale in the Missouri River Basin and may be interested in this as a pilot scale project;

-          particularly study the Pierre, SD area, where LaFramboise Island could be considered a larger-scale prototype of this linear island concept, in the Missouri River adjacent to Pierre);

-          or obtain state bonding funds as was done for Lake Redwood;

 

Phase 3:               Trail Development (utilize the investment)

-          Use the Island as a basis to develop a minimalist nature/walking trail (Windom Riverwalk);

-          would connect to mainland downstream at the Rolling Green sanitary sewer force main station property, adjacent to the Highway 62 bridge;

-          upstream connection has various possibilities;

-          could eventually interconnect with trail system building from Jackson;

-          would eliminate contentious issues with forced property acquisition for a trail along the river;

-          This would be the key selling point for landowners if further permission is needed beyond existing flowage easement;

-          would help people reconnect with the river and environemtn in a unique healthy manner;

-          trail could be closed during high water/spring nesting season;

-          environmental education tool for schools;

-          great attraction for city, something to be proud of, and may be a deciding factor for some to decide to move to Windom;

-          DNR Trails program and/or Transportation Enhancement funds could easily fund this phase.