Current and Upcoming Issues Confronting Inland Lakes

Alan Steinman, Ph.D.

Annis Water Resources Institute, GVSU

Major Issues

Nonpoint source pollution / Stormwater runoff

Invasive species

Landscaping: good, bad, and downright pitiful

Nonpoint Source Pollution

Nonpoint source (NPS) pollution comes from diffuse sources, such as septage, or rainfall and snowmelt moving over and through the ground.

Nonpoint Sources of Pollution

• Excess fertilizers, herbicides, and insecticides from agricultural lands and residential areas

• Sediment from improperly managed construction sites, crop and forest lands, and eroding streambanks

• Livestock, pet wastes, faulty septic systems, atmosphere

• Oil, grease, and toxic chemicals from stormwater runoff

Harmful Algal Blooms (HABs)

• Microcystin is the most common cyanotoxin produced by HABs → hepatoxin and tumor promotor.

• The U.S. currently has no national standards for exposure to microcystin or other algal toxins.

• WHO standards:

- drinking water: 1 µg/L- recreational: 20 µg/L

Microcystin Concentrations

Location Date Concentration (µg/L)

Musk. Lake (open)

7/16/07 34

Musk. Lake (HarborTowne)

7/16/07 158

Mona Lake 7/23/07 317

Data: Rick Rediske, AWRI

Stormwater Facts

Most of the NPS pollution comes during storm events

Stormwater discharges are generated by runoff from land and impervious areas during rainfall and snow events

• Paved streets• Parking lots• Building rooftops

Why Should We Care about Stormwater?

• Reduced recharge to aquifers

• Increased erosion & sedimentation

• Potentially toxic to stream biota

• Cost of infrastructure

Stormwater Examples

Land Use Change Analysis

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6000

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Land Use Categories

Spring Lake Land Use Change 1978-2006

1978

2006+79.40%

-42.32%+121.36%

-8.71%

Solutions Low Impact Development (LID) practices

Design natural infiltration to occur as close as possible to the original area of rainfall

Engineer terrain, vegetation, and soil features to optimize natural infiltration, allowing the landscape to retain more of its natural hydrological function

Best management practices, including riparian buffers, swales, rain gardens…

Invasive Species

• 1 new species arrives ~ 8 months1

1Ricciardi, A. 2001. CJFAS 58: 2513-2525.

• change in fish prey/food webs

• economic costs

Data: Tom Nalepa, GLERL

Diporeia

Data: Tom Nalepa, GLERL

Food Web Changes:Lake Michigan

Biomass

(Kilotons)1989 2006 2007

Prey Fish

(alewife; bloater)400 61 30

Quagga/Zebra mussels

0 212 245

Data: USGS, Great Lakes Science Center

Bighead Carp:

• feeds mostly on plankton, including both zooplankton and large, colonial phytoplankton (e.g. cyanobacteria)

• ecological concern over food web changes

Asian CarpAsian Carp

Silver Carp

• feeds mostly on phytoplankton• ecological concern over food web changes

From: Asian Carp Control Strategy Framework (Feb. 2010)

Actual asian carpfound

- all locations currently with confirmed, self-sustaining populations of bighead, silver, grass, or black carp have access to a large river, with at least 80 km that are free-flowing

River length requirement

- Kolar et al. (2007) identified 22 GL rivers “that may be suitable for spawning” based on lack of dams and minimum length of 100 km

- 7 of the 22 are in Lake Michigan:- 2 in the U.P.- 2 in WI- St. Joseph, Grand, and Pere Marquette

Vulnerable river systems?

Drowned rivermouths that could serve as good adult feeding habitat

Nico et al. 2005

- don’t really know how far they move

- usually associated with rapidly increasing flows

- big unknown and serious mgm’t need

Upstream spawning behavior

- thought to be in turbulent areas of rivers

- mouths of tributaries

- probably not in small tributaries

- may occasionally spawn in lakes, but eggs not thought to survive

Spawning location

Nico et al. 2005

• Can tolerate colder water, but Great Lakes temperature regime may be a metabolic limitation

• Need substantial amounts of plankton, so restricted to coastal, riverine areas

• Can they move from one riverine area to another?

Are They a Threat to the Great Lakes?

Submerged Aquatic Vegetation

Submerged Aquatic Vegetation

Hydrilla

• Grows up to 1 inch/day• Forms dense mats that block sunlight, killing off native plants below• Dense mats inhibit boating, swimming, & skiing• Slows movement of water, allowing sediment to build • Poor fish habitat • Found close to MI

Hydrilla

http://www.miseagrant.umich.edu/

• Need clear policy that prevents new invasive species from entering Great Lakes

• Need early detection monitoring program in most vulnerable locations—quarantine and eradication likely to be successful

Solutions

Landscaping IssuesLandscaping Issues

Courtesy: Progressive AE

1) Minimize lawn area2) Establish “greenbelt”

Courtesy: Progressive AE

Don’t dump in storm drains

Build a raingarden

Establish a greenbelt

Don’t add phosphorus fertilizer

Don’t dump in storm drains

Maintain greenbelt of trees

Small lawn area

Courtesy: Progressive AE

Minimize hardened shorelinesSeawalls deflect waves;

scour lake bottom

Seawalls prevent animal movement

(frogs)

Seawalls providepoor habitat

Some exotic plants prefer disturbed

habitat

10 Ways to Protect Your Lake:

1) Use no-phosphorus fertilizer

2) Use minimum am’t of recommended fertilizer

3) Apply fertilizer to lawn, not sidewalk

4) Don’t feed waterfowl near lake

10 Ways to Protect Your Lake:

5) Don’t burn leaves/clippings near lake

6) Plant buffer strip at lake’s edge

7) Promote runoff infiltration

8) Maintain wetlands

10 Ways to Protect Your Lake:

9) Maintain your septic system

10) Don’t be complacent

Websites for more information:

• www.michiganlakeinfo.org

• www.shoreline.msu.edu

• www.raingardens.org

www.gvsu.edu/wri