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Jun 13, 2023 275 likes •694 views

Welcome. Thank you for joining us! Lower Mississippi River Watershed Management Organization re so urc e ful. na tura lly. Lower Mississippi River Watershed Management Organization Watershed Restoration and Protection (WRAP) Study Janna

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re so urc e ful. na tura lly.

Welcome. Thank you for joining us!

Lower Mississippi River Watershed Management Organization

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re so urc e ful. na tura lly.

Lower Mississippi River Watershed Management Organization

Watershed Restoration and Protection (WRAP) Study

Janna Kieffer Barr Engineering April 16, 2013

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re so urc e ful. na tura lly.

T

  • nig ht’ s Ag e nda
  • Introductions
  • Shallow lake ecology
  • Lake “diagnoses”
  • Small group discussions
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re so urc e ful. na tura lly.

L

  • we r Mississippi Rive r Wa te rshe d

Ma na g e me nt Org a niza tio n

Includes portions

  • f 7 cities:
  • Inver Grove

Heights

  • Mendota

Heights

  • Sunfish Lake
  • South St. Paul
  • St. Paul
  • West St. Paul
  • Lilydale
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Wa te rshe d Re sto ra tio n a nd Pro te c tio n (WRAP)

  • Study includes four LMRWMO lakes:

–Sunfish (City of Sunfish Lake) –Pickerel Lake (Lilydale/St. Paul) –Thompson (West St. Paul) –Rogers (Mendota Heights)

  • Outcomes of study: Clean-up or Protection

Plan

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WRAP study fo c use s o n e xc e ss nutrie nts

  • The Problem: Cultural Eutrophication

“The accelerated increase in concentrations of nutrients, primarily phosphorus and nitrogen, in a lake as a result of human activities in the watershed”

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E xc e ss pho spho rus fue ls e utro phic a tio n

  • Phosphorus feeds algae and

causes algal blooms

  • Algae decreases water transparency
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  • the r sympto ms o f e utro phic a tio n

– Loss of dissolved oxygen in water near the lake bottom

–Shift in fish species from gamefish (bass & walleye) to non-game fish species tolerant

  • f low oxygen levels (carp & bullheads)
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Whe re do e s the pho spho rus c o me fro m?

External Sources

–Stormwater runoff from hard (impervious) surfaces –Leaves & grass clippings –Fertilizers –Pet/animal waste –Soil erosion –Septic systems

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Whe re do e s the pho spho rus c o me fro m?

Internal Sources

– Phosphorus can be stored in lake bottom sediments and released when oxygen levels are low

P P P P P P P

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Whe re do e s the pho spho rus c o me fro m?

Internal Sources

– Die-off of aquatic plants releases phosphorus to the lake water

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L a ke e c o lo g y: Sha llo w vs. de e p L a ke s

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L a ke e c o lo g y

There is a wide spectrum between deep lakes and wetlands

Deep Lakes Wetlands

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L a ke e c o lo g y

Deep Lakes Wetlands

Shallow lakes fall in middle of the spectrum Generally less than 10 feet deep, with max depth of 15 feet

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Sha llo w ve rsus de e p la ke s

Deep lakes thermally stratify- separating into layers based on temperature

Graphic from Fin Farm LLC (http://www.finfarm.com/aeration.php)

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Sha llo w ve rsus de e p la ke s

Shallow lakes do not form stable, distinct thermal layers

–Layers mix frequently throughout summer –Phosphorus released from bottom sediments will mix throughout summer

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Aq ua tic pla nts a re impo rta nt to a he a lthy sha llo w la ke

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Sha llo w la ke s ha ve two typic a l sta te s

1. Healthy clear water state

–Lush and diverse aquatic plant population –Clear water

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Sha llo w la ke s ha ve two typic a l sta te s

  • 2. Turbid State (algal dominated)

–Algae and sediment prevent aquatic plant growth –Without aquatic plants, water stays cloudy

  • Poor habitat for diverse fish

population

  • Wind and bottom feeding

fish re-suspend sediment

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Ho w do sha llo w la ke s shift to turb id sta te ?

Eutrophication

–Increased phosphorus from watershed fuels algae blooms

Changes in fish populations

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Dyna mic s o f fish po pula tio n a ffe c ts wa te r c la rity

  • Zooplankton feed on algae,

so its good to have healthy populations

  • Many predator species can’t

survive in shallow lakes due to low oxygen levels

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Less gamefish = more panfish and minnows More panfish = less zooplankton Less zooplankton = more algae

Dyna mic s o f fish po pula tio n a ffe c ts wa te r c la rity

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L MRWMO WRAP L a ke s

LMRWMO Shallow Lakes*

–Rogers Lake –Thompson Lake –Pickerel Lake

LMRWMO Deep Lakes*

–Sunfish Lake

* Included in WRAP study

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WRAP study- la ke dia g no se s

Monitoring and Sediment Analysis

Watershed Modeling Lake Water Quality Modeling Develop WRAP Plan

Monitoring helps diagnose lake problems

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WRAP study- la ke dia g no se s

Monitoring and Sediment Analysis

Watershed Modeling Lake Water Quality Modeling Develop WRAP Plan

Diagnosis based

  • n test and

model results

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Ro g e rs L a ke - Me ndo ta He ig hts

  • 107 acre lake
  • Shallow lake (max

depth 8 feet)

  • Watershed = 414

acres

  • Land use = low

density residential, park, golf course, highway

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Ro g e rs L a ke - pro g no sis is g o o d!

  • Water quality is good- focus on protection
  • Algae concentrations are generally low
  • Phosphorus coming from external (watershed)

sources AND some internal load

  • Abundant aquatic plant populations
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Ro g e rs L a ke - a q ua tic pla nt ma na g e me nt

  • Moderate densities of

Curlyleaf pondweed

  • Continued aquatic plant

monitoring recommended

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T ho mpso n L a ke - We st St. Pa ul

  • 7 acre lake/wetland
  • Shallow lake (avg depth 5-6 feet)
  • Watershed = 182 acres
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T ho mpso n L a ke - dia g no sis

  • Water quality does not meet standards
  • Primary phosphorus source is stormwater runoff from

developed watershed

  • Improvements will need to focus on reducing or treating

stormwater runoff

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T ho mpso n L a ke - a q ua tic pla nt ma na g e me nt

  • Moderate densities of

Curlyleaf pondweed (shown in red on figure)

  • Continued monitoring

is recommended

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  • 90 acres
  • Shallow lake

(max depth 11 feet)

  • Ivy Falls Creek drains

most of watershed

Pic ke re l L a ke

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Pic ke re l L a ke - dia g no sis

  • Water quality heavily influenced

by flood waters from Mississippi River

  • Mississippi River floods about
  • nce every 10 years
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Pic ke re l L a ke - dia g no sis

  • When flooding does not occur,

primary phosphorus sources are: – Runoff from Ivy Falls Creek watershed – Wetland directly west of Pickerel Lake

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Pic ke re l L a ke - dia g no sis

  • Protection and improvement measures should focus on

reducing or treating stormwater runoff

  • May consider management of adjacent wetland to

reduce phosphorus inputs to Pickerel Lake

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re so urc e ful. na tura lly.

Pic ke re l L a ke - a q ua tic pla nt ma na g e me nt

  • Moderate densities of

Curlyleaf pondweed (shown in red on figure)

  • Continued monitoring

is recommended

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Sunfish L a ke - City o f Sunfish L a ke

  • 51 acre lake
  • Deep lake (max depth

32 feet)

  • Watershed = 235 acres
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Sunfish L a ke - Dia g no sis

  • Water quality does not meet standards
  • Primary phosphorus source is internal load from lake

bottom sediments

  • Improvements will need to focus on reducing the

release of phosphorus from the sediments

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Sunfish L a ke - a q ua tic pla nt ma na g e me nt

  • Moderate densities of

Curlyleaf pondweed (shown in red on figure)

  • Eurasian Watermilfoil

identified

  • MN DNR to conduct

detailed plant survey

  • Continued monitoring is

recommended

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re so urc e ful. na tura lly.

Now, we want to hear from you!

  • What does the data mean to you?
  • How do we turn lake data into

impactful community knowledge?

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re so urc e ful. na tura lly.

Thanks for sharing your time with us tonight!