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An Update on the Status of Iowa's Shallow Lake Renovations
Vince Evelsizer – Iowa Dept. of Natural Resources
Talk Outline • Intro/background of our shallow lakes
• Update on progress
• Successes
• Challenges
• Individual shallow lake profiles
• What’s been learned - future management
Introduction/Background
What Changed – Shallow Lakes Died
• Major changes in hydrology
• High and stable water levels
• Wetland loss in their watersheds
• Increased nutrients and sediment
• Little to no aquatic vegetation
• Open, wind swept
• Abundance of rough fish
(carp, bullhead and fathead minnows)
Some have been this way for 50 – 80 years!
Scientific Literature to Support Changes….
Fortunately many studies have documented several aspects of shallow lake ecology and the management implications
Studies produced from: • Canada • Minnesota • Netherlands/Europe • Other Midwest States
Diamond Lake Dedication, July 2009
Partners
• NAWCA
• Lakes Restoration Program
• Lake Associations
• Hundreds of local citizens and businesses
• Ducks Unlimited
• Pheasants Forever
• Iowa Natural Heritage Foundation
• The Nature Conservancy
• U.S. Fish and Wildlife Service
• U.S. Dept. of Ag (WRP, CRP, etc.).
• DNR programs and staff
• others
The vision for Living Lakes is to establish stepping-
stones of perpetually protected and managed shallow
lake/marsh complexes from southern Iowa through
northern Minnesota to provide quality wetland food
and habitat resources for waterfowl. The initiative will
help preserve this region’s rich waterfowling heritage
and support conservation of the primary source of its
birds, the prairie breeding grounds.
The Living Lakes Vision
Courtesy of DU
Diamond Lake, 2009
Shallow Water Management requires a
watershed and in-lake approach
In – Lake “Renovations” Getting water level control !
Drawdown and Carp Removal
In-Lake; Replacing old water control structures
Pickerel Lake July 2014 – New Control Structure
Updates on Progress
The top priority for renovating shallow lakes is getting back their
Ecological Health
Successes
• 37 projects; >14,000 acres affected
• Shallow lakes/wetlands – positive abiotic/biotic response in all cases so far
• Lots of partnering and communication
• Monitoring
• Funding has been available
• In many cases several types of recreational use has spiked upward
• Some examples…..
West Hottes/Marble
Renovated in 2014 – series of water control structures
Wildlife Use – West Hottes/Marble
West Hottes Opening day of duck season
Trumbull Lake
Renovations started in 2012; more done through 2014 ‘Mini-drawdowns’ (~14 inches) occurring 2014 – 2016 Challenge: Carp re-entry
Ventura Marsh
Renovation: 2009 – 2012
Aquatic Veg, clearer water, muskrats!
Challenge – Carp re-entry
Dan Green Slough Pre - renovation
Dan Green Slough - Post - Renovation
A large marsh renovated 2009 – 2012
Rice Lake
Renovation started in 2012
Challenges – phosphorous/algae blooms
New WCS – Rice Lake
IA DNR Shallow Lakes Monthly
Monitoring Schedule
Sample Months Number of Lakes
to Monitor Regular Sampling (WQ and Nutrients)
Plankton Plants Inverts Fish
May
16
X X
June
16
X X
July
16
X X X X
August
16
X X X
Sept
16
X X
Challenges
• Trees
• Fish
• The wrong kind of aquatic vegetation response
• Weather
• Nutrient/pollutant/broken watersheds
• Different opinions – recreational use
• Some examples….
Diamond Lake – Renovation completed by 2009
Diamond Lake – Aquatic Vegetation
Diamond Lake – Post Renovation
Illustrates Annual Changes - Dynamic
Virgin Lake – October 2014
Challenge – ‘Looks’, dead trees; however very good wildlife response
Ethan’s 1st Duck – Virgin Lake
Lizard Lake – Post Renovation
Challenge - Hybrid Cattail Domination
Things can get complicated ! Shallow Lake & Marsh Management is a Science and an Art
A perfect example of “adaptive resource management”
Hmmm…Should I put some more stop logs in? How many? How much will it rain?
This can be complicated for a multi-use shallow lake. People care about the outcome; the managers hope it works out!
It’s an iterative, dynamic process!
• Shallow Lake Mgmt – Rapid Evolution
– Fairly finite resource in Iowa
– Active mgmt on places that hadn’t had it for yrs
– A big deal locally
– New and old partners are needed
– Community support needed for success
– Manage for WQ and ecol health
Future
• Wide variety of partners; community support; waterfowl managers need to embrace this!
• Shallow lake management plans – clear up details
• Monitoring parameters will document and trigger mgmt decisions – science
• Each shallow lake is unique
• Some compromises are needed, any positive changes to a system is better than nothing…
Take – Home Messages Shallow lake renovations: Are they working? - YES! ……so far anyway - Not easy, require a lot of steps, money, patience, - Shallow lakes are dynamic - Communication is key - Community support is key - Partners and cooperation is key - Monitoring and follow-up are necessary - Whole system/Ecological/Water Quality Driven
Questions?
Fish Complicate the Management Process - What assemblage of game fish? - Fish take awhile to grow - Shallow Lakes are dynamic; not stable - Effects the timing of renovations