impacts of beaver dam removal - lake superior...impacts of beaver dam removal . hannah behar and...

Impacts of

Beaver Dam Removal

Hannah Behar and Emma Burgeson

M.S. students in Water Resources Science

University of Minnesota Duluth

Research Question: How do beaver dams impact

watershed hydrology?

1. Water source & storage

2. Discharge

3. Temperature

4. Temporal variation

The Knife River Watershed

https://www.pca.state.mn.us/sites/default/files/wq-iw10-01e.pdf

Forest Cover


GAP Level 3 Acres Percentage Aquatic 69 0%

Aspen/White Birch 37944 69% Barren 95 0% Black Ash 652 1% Cropland 807 1% Developed 604 1% Grassland 2336 4% Lowland Black Spruce 115 0%

Lowland Northern White-Cedar

1371 2%

Lowland Shrub 5353 10% Maple/Basswood 1338 2% Marsh 20 0% Pine 619 1% Spruce/Fir 2541 5% Tamarack 387 1% Upland Cedar 261 0% Upland Conifer 14 0% Upland Shrub 831 2% Total 55359 100%

Forest Cover


GAP Level 3 Acres Percentage Aquatic 69 0% Aspen/White Birch 37944 69% Barren 95 0% Black Ash 652 1% Cropland 807 1% Developed 604 1% Grassland 2336 4% Lowland Black Spruce 115 0%

Lowland Northern White-Cedar

1371 2%

Lowland Shrub 5353 10%

Maple/Basswood 1338 2% Marsh 20 0% Pine 619 1%

Spruce/Fir 2541 5% Tamarack 387 1% Upland Cedar 261 0% Upland Conifer 14 0% Upland Shrub 831 2% Total 55359 100%

Surficial Geology ● Highland Moraine

● Transitional area

● Superior Lobe Clay Plain

Gran 2016 hthttps://www.flickr.com/photos/jsjgeology/22162400130/in/photostream/

Surficial Geology ● Infiltration of < .05 inches / hour ● Recharge rate of 8.4 inches / year ● very low infiltration capacity → high

overland flow potential

Gran 2016 https://imnh.iri.isu.edu/digitalatlas/hydr/concepts/surfhyd/srfwtr.htm

Discharge ● Knife River is strongly

dependent on runoff to maintain flows

● Flashy response to precipitation events

http://stream1.cmatc.cn/pub/comet/HydrologyFlooding/hydrograph/comet/hydro/basic/UnitHydrograph/print_version/02-terminology.htm

Discharge ● Strongly dependent on

runoff to maintain flows


Snow accumulates




April




August

Research Question: How do beaver dams impact watershed hydrology under low flow conditions?

https://content.ces.ncsu.edu/natural-stream-processes

Knife River Watershed

DNR estimates 0.6 beaver colonies / river mile across Minnesota

0.6 x 181 → potential for roughly 109 beaver colonies

(Bouwes et al. 2016)



1. Water source & storage

● Storage in ponds

● Infiltration and exchange

with groundwater

● Upwelling

https://www.researchgate.net/publication/319043632_To_What_Extent_Might_Beaver_Dam_Building_Buffer_Water_Storage_Losses_Associated_with_a_Declining_Snowpack/figures?lo=1



2. Discharge

● Impoundments may reduce

peak flows

● Seasonal variation

https://utahcbcp.org/ou-files/boxelder/BeaverPresentation_PortugalSept2015.pdf



3. Temperature

● Pond surface

● Deep water

● Below the dam

(Bouwes et al. 2016)

Project Sites

4 paired watersheds with similar characteristics

8 total sites

Combination of state and private land

Needed to have active beavers AND landowner permission

Project Sites

Sites 1 and 2 were chosen for their upland features

Headwaters

Lower relief

Hummocky morainal area

Project Sites

Sites 3 and 4 were lower in the stream

Greater relief

Flashier systems

In lake clay area

Project Sites

“B” sites will have beaver and dams both years

“T” sites will have beavers and dams the first year, but not the second

What Are We Doing and Why? ● Mapping beaver dams and ponds ● Measuring velocity and stage height of stream ● Collecting water samples ● Collecting temperature data ● Estimating evaporation

Summer 2018 1. Installed equipment

a. Stream gauges b. Shallow groundwater wells c. Air and water temperature loggers d. Evaporation pans

2. Water samples collected 3. Velocity measured 4. Rating curves created

Equipment Stream Gauge

Stage Height

Stream samples come from a riffle near the gauges at each site

Equipment Shallow Groundwater Well

Height of water table continuously recorded

Groundwater samples

Equipment Pressure Transducer

Records the pressure of water above the device

Mostly deployed in streams and wells

1 deployed to measure barometric pressure

Stable Isotope Samples and Analysis Stable isotopes 2H (deuterium) and 18O to help determine the source of water in the streams

Samples come from: ponds, streams, shallow wells, precipitation collectors, and deep groundwater wells from landowners

Chemical separation of baseflow

Temperature Analysis What do beaver ponds do to the temperature of water?

Fall 2018: Mapping Storage Capacity and Dam Characteristics Bathymetry + Surface Area = Volume of water in each pond

Moving Forward Data Crunching

Water samples will be analyzed for isotopic signatures

Discharge calculated

Temperature data

Treatment will resume in half of the sites in spring/summer of 2019

Outreach Undergraduate field days

Taking out family and friends

Speaking with landowners Future conferences

Any ideas? Let us know!

Project Collaborators

Dr. Karen Gran - Principal Investigator

Dr. Salli Dymond - Co - Investigator

Dr. Rebecca Teasley - Co- Investigator

Josh Dumke, M.S. - Co- Investigator and NRRI Fish Biologist

Deserae Hendrickson - Collaborator and MNDNR Duluth Area Fisheries Supervisor

Hannah Behar - WRS graduate student

Emma Burgeson - WRS graduate student

Nick Peterson - civil engineering graduate student

Craig Steiskal - field assistant

Lizzie Boor - field assistant

Lara Scott - WRS graduate student, field crew

Thank You

impacts of beaver dam removal - lake superior...impacts of beaver dam removal . hannah behar and...

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