Adaptive methods to restore Lake Erie hydrology_Kroll

Roy Kroll Ducks Unlimited, Inc.Great Lakes / Atlantic Regional OfficeAnn Arbor, MI

GLRI Coastal Wetland Restoration Success Stories

Adaptive methods to restore Lake Erie hydrology and coastal marsh at Middle Harbor, Ohio

Lake Erie

Middle Harbor

Sediment plumes from clay soils

Lake Erie coastal wetland extent = Lake Erie water levels

Lake Erie water levels fluctuate over various time periods

• Short - stormwater & seiches*• Medium : annual and seasonal• Long: multiple years or decades

*Seiches – wind induced water level changes Northeast or Southwest winds Common - 3 ft. in 24 hrs.Record - 8 ft. (12-14 ft. waves)

Seiche effect

Ohio.gov

Natural historical pattern: transient wetlands

Pre-settlement coastal wetland extent (ODNR Ohio Coastal Atlas, 2007)

• Deforested, channelized and tile-drained landscape

• Agricultural and municipal flood-control dikes

• Introduction of carp - increased turbidity

• Geologic subsidence and steep hydrological gradient

Landscape-level factors and L.E. coastal wetland extent

Mitsch & Wang 1998

Impacts of landscape alterations:

Landward migration blocked – high water years = wetland loss

To sustain emergent marshes - dikes, pumps, pipes, & water level control was required

Ecological benefits - mainly in impoundments

Events affecting coastal marshes in Southwest Lake Erie basin, 1860-1970

Private land –subsistence &duck hunting clubs

Great Black Swamp is drained farmland

Flood protection dikes –restrictlandward advance

1970: Ecological shortcomings publicized• fisheries focus (e.g., Northern pike)

1940: Diked marshes common in SWLE

1950: Science-based wetland management• waterfowl focus, state/fed acquisitions

Nearly 30 years of high water & NE storms eliminated most coastal wetlands including those protected by dikes, and launched an era of intensive wetland restoration. Currently, 95% of SWLE coastal wetlands are essentially impounded.

Lake levels at or below long-term average for 12 years demonstrated that natural reestablishment of diverse wetlands did not occur on a substantive scale in SWLE.• largely prevented by invasive species colonization (i.e., Phragmites)

However, new opportunities exist for increasing ecological functions of diked marshes, because at many sites current lake levels will sustain aquatic macrophytes. • potential exists to install structures that restore Lake Erie hydrology and maintain desired emergent marsh plants.

Need for Restoration

• Large wetland (350 acres)• Little/no aquatic vegetation• No hydrologic exchange• Adjacent to higher-quality waters• Turbid, shallow (< 3 ft.) water • No dike construction required

Middle Harbor

Middle Harbor (East Harbor State Park)

Construction of water conveyance and control structure including a

removable pump 350 acres of marsh will be

restored and open to fish passage

Funded by $643,397 NOAA grant with $31,200 Ohio DNR match

Structure location

Lake Erie

Adapting old restoration & management techniques to provide broader ecosystem benefits

1. Design and build the structure (DU engineering)

2. Establish the wetland plant community (2 years)

3. Open the gates to restore Lake Erie hydrology

4. Monitor everything

Middle Harbor Project

Long term goal: Lake Erie hydrology sustaining high quality* coastal marsh

Structure is versatile and adaptable from a marsh management perspective• Options: full open flow, carp screens, stoplogs, flapgate, screwgate, and pumping

Middle Harbor and Erie Marsh Joint Biological Monitoring Program (Pre- and Post-Construction)

Water quality sampling: DO, conductivity , pH, temp., etc

Species abundance & diversity for:• Vegetation: transects and point counts (VIBI)• Fish: larval tows, trap nets, electrofishing (PSD, IBI)• Herps: calling surveys, ground surveys • Birds: calling & visual surveys, transect and point counts

Table 1 – Middle Harbor (MH – Project Site) compared to East Harbor (EH – Control Site) – July 2011

Common Name Final Count Total Deformities Total Tumors Notes MH EH MH EH MH EH

Gizzard shad 772 87 1 1 Same fish with 2 anomalies Brook silverside 5 326 3 Emerald shiner 20 388 Alewife 11 34 1 Bluegill 18 215 1 Largemouth bass 3 White crappie 3 White perch 1 Unknown clupeidae 1 Larvae decomposed cannot

identify to species TOTAL COUNT 834 1,050 1 5 1 0

Middle Harbor Wetland Establishment Schedule

2012-2013

• Winter/spring: Gravity de-watering using open flows & seiche events

• Late spring: Pump water to expose mudflats & germinate seeds - Provide water reservoir for mussels

- Provide live fish removal effort

• Aerially seed cover crop (annual millet) if needed

• Re-flood gradually over mid-late summer

2014• Partial de-watering; establish perennials

Thank You to our Partners:

Field Trips:Board on the 1st floor, West Superior Ave

entrance (bottom of Grand Staircase)Trolleys board 2:30

Joint Reception: trolleys begin departing at 5:45

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HOW12

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