Indiana Lakes Management Society

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Indiana Lakes Management Society Indiana Lakes Management Society (ILMS) promotes the understanding and comprehensive management of Indiana lakes, reservoirs and watershed ecosystems

Primary objectives:

-Promote and provide a forum for the sharing of information and experience on scientific, legal, administrative, and financial aspects of lake and watershed management.

-Foster and assist in the development of local lake restoration and protection programs in accordance with appropriate management strategies and techniques.

-Encourage the cooperation and interaction of organizations, agencies, units of government, and individuals concerned with lake and watershed management and protection.

-Encourage, support and assist in the development of local, state and national programs, policies, and legislation promoting lake and watershed management.

-Encourage development and enforcement of laws and legislation designed to protect vital water resources and their environments.

💧 BEYOND THE SURFACE WEDNESDAYTWO LAKES. SAME RAINFALL. DIFFERENT CHEMISTRY. WHY?Imagine two lakes receiving the same ra...
10/14/2026

💧 BEYOND THE SURFACE WEDNESDAY

TWO LAKES. SAME RAINFALL. DIFFERENT CHEMISTRY. WHY?

Imagine two lakes receiving the same rainfall.

One lake experiences very little change in pH, while the other is much more sensitive to acidic inputs.

What makes the difference?

The answer may be something you've never measured in your lake: ALKALINITY!

Alkalinity describes water's ability to neutralize acids and resist changes in pH.

Think of it as a chemical buffer.

In many Indiana lakes, alkalinity comes primarily from bicarbonate and carbonate associated with local geology.

Here's where it gets interesting:

🪨 Lakes surrounded by limestone-rich geology often have relatively high alkalinity.

💧 Lakes with low alkalinity can be more sensitive to acid inputs.

🔬 Two lakes can have similar pH measurements but very different abilities to resist future changes.

HERE'S YOUR SCIENCE CHALLENGE:

If your lake has a pH of 8.2, does that automatically mean it has high alkalinity?

No!

pH measures how acidic or basic the water is at that moment. Alkalinity measures its acid-neutralizing capacity.

Both measurements provide important information about lake chemistry.

💬 Have you ever had your lake's alkalinity tested, or do you typically monitor only pH?

10/14/2026

🐟 LAKE IQ ANSWER REVEAL!

The correct answer is C!

This is an example of something scientists call a trophic cascade.

Here's how it works:

🐟 More fish that feed on zooplankton can mean fewer large grazing zooplankton.

🦠 Fewer zooplankton can mean less grazing pressure on algae.

💚 Less grazing can allow algae populations to increase, potentially reducing water clarity.

And the bonus answer? Zooplankton!

Some species, particularly large-bodied Daphnia, are extremely effective at consuming phytoplankton.

This is one reason fisheries management and water quality management are closely connected.

THE TAKEAWAY: Sometimes what's happening at the top of the food web can have surprising effects all the way down to microscopic algae.

🐟 TEST YOUR LAKE IQ TUESDAY!CAN ADDING FISH ACTUALLY MAKE A LAKE GREENER?Imagine a lake manager introduces a large numbe...
10/13/2026

🐟 TEST YOUR LAKE IQ TUESDAY!

CAN ADDING FISH ACTUALLY MAKE A LAKE GREENER?

Imagine a lake manager introduces a large number of small fish that feed primarily on zooplankton.

What might happen to the lake's water clarity?

A. Water clarity will always improve because fish consume nutrients.

B. Water clarity will remain unchanged because fish don't influence algae.

C. Water clarity could decrease because fewer zooplankton are available to eat algae.

D. Algae will disappear because fish release oxygen into the water.

🔎 BONUS QUESTION: What tiny aquatic organisms play an important role in controlling algae populations?

👇 Share your answer and reasoning in the comments!

We'll reveal the answer tomorrow.

MYTH VS. FACT MONDAY❌ MYTH: Leaves are natural, so it doesn't matter how many end up in the lake.✅ FACT: Too many leaves...
10/12/2026

MYTH VS. FACT MONDAY

❌ MYTH: Leaves are natural, so it doesn't matter how many end up in the lake.

✅ FACT: Too many leaves entering your lake can contribute to nutrient loading!

Fall in Indiana means beautiful colors, cooler temperatures, and LOTS of falling leaves.

While leaves are a natural part of lake ecosystems, excessive amounts of organic material can create water quality challenges.

🍂 As leaves decompose, they release nutrients, including phosphorus and nitrogen.

💧 Microorganisms breaking down leaves also consume dissolved oxygen.

🌿 Keeping excess leaves out of storm drains and away from the shoreline can help reduce unnecessary nutrient inputs.

YOUR FALL LAKE STEWARDSHIP CHALLENGE:

Instead of blowing leaves into the lake or street, consider mulching them into your lawn or using them in your garden!

💬 How do you manage fall leaves around your lake property?

THE DISAPPEARING LAKE!Imagine waking up one morning to discover that your lake has practically vanished.No broken dam. N...
10/10/2026

THE DISAPPEARING LAKE!

Imagine waking up one morning to discover that your lake has practically vanished.

No broken dam. No massive drought. Just water disappearing into the ground.

Sounds impossible, right?

Not in certain parts of the world!

Some lakes form in landscapes known as karst terrain, where groundwater gradually dissolves rocks such as limestone, creating underground passages, caves, and sinkholes.

Under certain conditions, lake water can drain through these underground openings, causing water levels to drop dramatically.

Some disappearing lakes even refill when rainfall or groundwater conditions change!

And here's the Indiana connection...

Southern Indiana is home to extensive karst landscapes, complete with caves, sinkholes, and underground drainage systems.

While disappearing lakes aren't a common feature of Indiana's glacial lake region, the geology beneath southern Indiana demonstrates just how complicated groundwater systems can be.

Sometimes a lake's most interesting feature isn't what you can see. It's what's happening underground!

🌊 LAKE FACT FRIDAY!DID YOU KNOW YOUR LAKE HAS AN UNDERWATER MIGRATION HAPPENING ALMOST EVERY DAY? 🤯Forget migrating bird...
10/09/2026

🌊 LAKE FACT FRIDAY!

DID YOU KNOW YOUR LAKE HAS AN UNDERWATER MIGRATION HAPPENING ALMOST EVERY DAY? 🤯

Forget migrating birds for a moment. Some of the smallest creatures in your lake are making incredible daily journeys!

Meet zooplankton—tiny aquatic organisms that play an important role in lake food webs.

Many zooplankton participate in something called diel vertical migration.

🌙 At night, they move closer to the surface to feed on algae.

☀️ During the day, they retreat into deeper, darker water, where they're less visible to fish and other predators.

Some species travel several meters vertically every single day!

Here's the really interesting part: Their migration patterns can influence where algae are consumed and how nutrients move through the water column.

🔬 Not all zooplankton migrate this way. Their behavior depends on factors such as light, temperature, oxygen, and predator abundance.

💬 FUN QUESTION: Did you know that some of your lake's smallest residents are constantly on the move?

10/09/2026

ANSWER REVEAL LAKE DETECTIVE THURSDAY

CASE SOLVED: ✅ B. Fall turnover is occurring.

As surface water cools, it becomes denser and the temperature difference that maintained summer stratification weakens. Wind can then mix the water column more completely.

Fall turnover redistributes temperature, oxygen, and nutrients throughout the lake. It’s a normal part of the seasonal cycle in many Indiana lakes and one of the biggest changes happening beneath the surface each fall.

🔎 Detective Note: The lake may look quiet in October, but underneath the surface, the entire water column can be reorganizing.

🕵️ LAKE DETECTIVE THURSDAYCASE FILE #0012: The Lake That Suddenly Looks Different 🍂🟡 Difficulty: Field InvestigatorTHE ...
10/08/2026

🕵️ LAKE DETECTIVE THURSDAY

CASE FILE #0012: The Lake That Suddenly Looks Different 🍂
🟡 Difficulty: Field Investigator

THE MYSTERY

All summer, the lake had distinct layers of warm surface water and cold deep water. Now fall has arrived, temperatures are dropping, and something is changing.

THE CLUES

🍂 Cool fall nights have lowered surface-water temperatures.
💨 Fall winds are getting stronger.
🌡️ The temperature difference between surface and deep water is disappearing.
🔄 Water is beginning to mix from top to bottom.

What’s happening to the lake?

A. The lake is beginning to freeze.
B. Fall turnover is occurring.
C. Groundwater has stopped entering the lake.
D. The lake is losing water from the bottom.

👇 What’s your diagnosis, Lake Detective?

🔬 BEYOND THE SURFACE WEDNESDAYYOUR LAKE HAS A MEMORY. AND IT'S BURIED IN THE MUD!What if we told you that scientists can...
10/07/2026

🔬 BEYOND THE SURFACE WEDNESDAY

YOUR LAKE HAS A MEMORY. AND IT'S BURIED IN THE MUD!

What if we told you that scientists can investigate a lake's history without having decades of water quality data?

The secret is beneath the lake.

Lake sediments accumulate over time, preserving evidence of past environmental conditions.

By collecting sediment cores and analyzing the layers, scientists can investigate:

🔬 Historical changes in nutrient enrichment.

🌿 Evidence of past algae populations.

🏡 Changes associated with watershed development and land use.

🌎 Historical environmental conditions, sometimes extending back hundreds or thousands of years.

Scientists may examine fossilized diatoms, pigments, pollen, and sediment chemistry to reconstruct a lake's environmental history.

This field of science is called PALEOLIMNOLOGY.

But there's a catch! Sediment layers don't automatically tell scientists how old they are. Researchers often use specialized dating techniques to establish when those layers accumulated.

💬 LET'S THINK LIKE SCIENTISTS:

If you could collect a sediment core from your lake, what would you most want to investigate about its history?


*Photo Courtesy of King County, Washington

10/07/2026

WATER QUALITY WORD WEDNESDAY

WORD OF THE WEEK: ANOXIA

Anoxia describes a condition where dissolved oxygen is essentially absent from the water.

In lakes, anoxic conditions can develop in deeper water when the lake is stratified and oxygen is consumed faster than it can be replaced.

Why does this matter?

Anoxia can influence:

🐟 Available habitat for fish
🦠 Microbial activity
🧪 Nutrient cycling
🌊 Chemical reactions at the sediment-water interface

In some lakes, low-oxygen or anoxic conditions near the sediment can also contribute to the release of previously stored phosphorus back into the water column.

It's one reason lake managers often collect temperature and dissolved oxygen profiles at multiple depths instead of measuring only at the surface.

Address

207 S Wayne Street, Ste B
Angola, IN
46703

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