Welcome. Thank you for joining us! Lower Mississippi River Watershed Management Organization

Transcription

1 Welcome. Thank you for joining us! Lower Mississippi River Watershed Management Organization

2 Lower Mississippi River Watershed Management Organization Watershed Restoration and Protection (WRAP) Study Janna Kieffer Barr Engineering April 16, 2013

3 Tonight s Agenda Introductions Shallow lake ecology Lake diagnoses Small group discussions

4 Lower Mississippi River Watershed Management Organization Includes portions of 7 cities: Inver Grove Heights Mendota Heights Sunfish Lake South St. Paul St. Paul West St. Paul Lilydale

5 Watershed Restoration and Protection (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

6 WRAP study focuses on excess nutrients 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

7 Excess phosphorus fuels eutrophication Phosphorus feeds algae and causes algal blooms Algae decreases water transparency

8 other symptoms of eutrophication Loss of dissolved oxygen in water near the lake bottom Shift in fish species from gamefish (bass & walleye) to non-game fish species tolerant of low oxygen levels (carp & bullheads)

9 Where does the phosphorus come from? External Sources Stormwater runoff from hard (impervious) surfaces Leaves & grass clippings Fertilizers Pet/animal waste Soil erosion Septic systems

10 Where does the phosphorus come from? Internal Sources Phosphorus can be stored in lake bottom sediments and released when oxygen levels are low P P P P P P P

11 Where does the phosphorus come from? Internal Sources Die-off of aquatic plants releases phosphorus to the lake water

12 Lake ecology: Shallow vs. deep Lakes

13 Lake ecology There is a wide spectrum between deep lakes and wetlands Deep Lakes Wetlands

14 Lake ecology Deep Lakes Wetlands Shallow lakes fall in middle of the spectrum Generally less than 10 feet deep, with max depth of 15 feet

15 Shallow versus deep lakes Deep lakes thermally stratify- separating into layers based on temperature Graphic from Fin Farm LLC (

16 Shallow versus deep lakes Shallow lakes do not form stable, distinct thermal layers Layers mix frequently throughout summer Phosphorus released from bottom sediments will mix throughout summer

17 Aquatic plants are important to a healthy shallow lake

18 Shallow lakes have two typical states 1. Healthy clear water state Lush and diverse aquatic plant population Clear water

19 Shallow lakes have two typical states 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

20 How do shallow lakes shift to turbid state? Eutrophication Increased phosphorus from watershed fuels algae blooms Changes in fish populations

21 Dynamics of fish population affects water clarity 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

22 Dynamics of fish population affects water clarity Less gamefish = more panfish and minnows More panfish = less zooplankton Less zooplankton = more algae

23 LMRWMO WRAP Lakes LMRWMO Shallow Lakes* Rogers Lake Thompson Lake Pickerel Lake LMRWMO Deep Lakes* Sunfish Lake * Included in WRAP study

24 WRAP study- lake diagnoses Monitoring and Sediment Analysis Watershed Modeling Lake Water Quality Modeling Develop WRAP Plan Monitoring helps diagnose lake problems

25 WRAP study- lake diagnoses Monitoring and Sediment Analysis Watershed Modeling Lake Water Quality Modeling Develop WRAP Plan Diagnosis based on test and model results

26 Rogers Lake- Mendota Heights 107 acre lake Shallow lake (max depth 8 feet) Watershed = 414 acres Land use = low density residential, park, golf course, highway

27 Rogers Lake- prognosis is good! 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

28 Rogers Lake- aquatic plant management Moderate densities of Curlyleaf pondweed Continued aquatic plant monitoring recommended

29 Thompson Lake- West St. Paul 7 acre lake/wetland Shallow lake (avg depth 5-6 feet) Watershed = 182 acres

30 Thompson Lake- diagnosis 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

31 Thompson Lake- aquatic plant management Moderate densities of Curlyleaf pondweed (shown in red on figure) Continued monitoring is recommended

32 Pickerel Lake 90 acres Shallow lake (max depth 11 feet) Ivy Falls Creek drains most of watershed

33 Pickerel Lake- diagnosis Water quality heavily influenced by flood waters from Mississippi River Mississippi River floods about once every 10 years

34 Pickerel Lake- diagnosis When flooding does not occur, primary phosphorus sources are: Runoff from Ivy Falls Creek watershed Wetland directly west of Pickerel Lake

35 Pickerel Lake- diagnosis 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

36 Pickerel Lake- aquatic plant management Moderate densities of Curlyleaf pondweed (shown in red on figure) Continued monitoring is recommended

37 Sunfish Lake- City of Sunfish Lake 51 acre lake Deep lake (max depth 32 feet) Watershed = 235 acres

38 Sunfish Lake- Diagnosis 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

39 Sunfish Lake- aquatic plant management Moderate densities of Curlyleaf pondweed (shown in red on figure) Eurasian Watermilfoil identified MN DNR to conduct detailed plant survey Continued monitoring is

40 Now, we want to hear from you! What does the data mean to you? How do we turn lake data into impactful community knowledge?

41 Thanks for sharing your time with us tonight!