Pond Boss Forums Thread Like Summary - Declining Water Level

Thank you all for your valuable insight. I joined the forum today so I'm going through previous threads now. I apologize if this has been asked and answered umpteen times.

My wife and I and six other couples just built houses in a new development three years ago. We're on a 15 acre "lake" in western WI (Pond Boss Forum seemed more appropriate for my questions than a "lake" forum). The lake is a seepage lake with no inflow or outflow. Lake levels are down about three feet from when we moved in three years ago. Max depth was 16' three years ago. We had a lot of snow in the winter of '22-'23 and a lot of rain so far this year and it seems like the water level goes down a little every week.

I'm talking to my fellow HOA officers about what we can do. Have any of you tried to drill a well deep enough to pump water into your ponds? Is it possible to make a difference doing that in a 15 acre lake? Someone had told me that we need to find the springs that feed the lake and "clean them out" so water will come in as fast as it's going out. He also told me to replace my car tires' winter air with summer air, so he may be full of crap.

Thanks for any insight you can provide

Welcome to the forum!

Cleaning out the Springs will do nothing. Springs do NOT have a one way valve on them, so if the water pressure is higher in the lake than in the spring, it will flow backwards. What you have is called a groundwater lake, I have a groundwater pond. For the last 3 1/2 years mine was as low as 9 feet vertically below full pool.

You can pump water into it to fill it, but first you have to know how much water you are loosing.

Go get a metal yardstick and a piece of stiff plastic or EMT tubing. Pound that down into the pond bottom and zip tie the yardstick to it so you can read it easily and the yardstick doesn't slide up or down on the tubing. Put it in 12"-24" of water and once it's in there make a note where the water level is. Look at it daily and record the measurement. After a week you will get a good idea how fast it's dropping (vertically).

1" drop in a 15 acre lake equates to 407,313 gallons of water.

Are you in Hudson, WI?

How close is your lake to the St. Croix river?

Frequently, in areas with lots of groundwater ponds and lakes, the adjacent rivers and streams are "effluent waterways" -- that is, they have cut their channels below the water table. IF that is the case in your area, then you have a rough way to sample your local water table.

Immediately after a big rain (or the main spring thaw) the rivers and streams will run very high for a few days or a week, since the surface water inflows to the river will exceed the rate at which water can be infiltrated back into the groundwater aquifer. However, after equilibrium is reached, the water level in the river will be indicative of the water level in the aquifer. (The water in the aquifer will normally be a little higher based on the slope of the land, permeability of the aquifer material, etc.)

Therefore, if my assumptions are correct, and if there are some nearby streams or rivers where you can gauge the elevation of the waterway, then you have a crude system to determine if the water level in your aquifer is declining or increasing.

The south-central portion of the U.S. has been in drought conditions for much of the past three years. Consequently, many groundwater aquifers declined substantially in those areas. I did not watch the past data for your area. Have you had below average precipitation over that time frame, or has it been close to average?

If it has been below average, then I am optimistic that your lake should show some recovery.

I am a geologist, so I can give general observations about groundwater aquifers. I have NOT studied the groundwater geology in your area.

Here is a little analogy to help you understand your "groundwater" lake. Imagine that you have an inground hot tub in your backyard beside your inground pool. The hot tub is 4' deep and the pool is 10' deep. However, they are connected by a 12" pipe that runs from the bottom of the pool into a vertical riser that comes up in your hot tub. The hot tub is your lake and the swimming pool is the surrounding groundwater aquifer.

As a drought slowly depletes the water in the pool, the water level in your hot tub will exactly match the water level in the pool. Likewise, if you get a big rain that goes into the pool, then the water level in the hot tub will also rise, even if the cover was on and no rain directly ran into the hot tub.

This is why I disbelieve the advice to clean out the springs that supply water to your lake. There are no "valves" on underground springs, as they let water in, so will they let water out. The driving force is the potentiometric surface (theoretical unrestrained water level) at any point in the aquifer. For example, if you added an inch of water to the hot tub, it would equalize by flowing most of the added water to the swimming pool (dependent upon their relative volumes). However, if you added an inch of water to the pool, then the water would go up almost the entire inch in the hot tub.

That long-winded description was also to explain to you the problem of trying to drill a water well and raise the water level in your lake. Imagine the case when your hot tub and pool are both one foot low due to dry conditions. If you ran a garden hose into your hot tub and started to raise the water level, it would all immediately transfer to the pool through the 12" connecting pipe. If the evaporative water losses from the pool were equal to the water input from the garden hose, then you would not observe any rise of either body of water. This is why the water well probably will not work.

However, the real world is more complicated than my analogy. In reality the aquifer that is attached to your lake may actually have limited permeability (the ability to transmit fluid flows). In that case, then adding water to the lake might actually raise the water level if the outflow into the aquifer is very low. Go back to the pool and hot tub. If the connector is only a 1/4" pipe, then the water level in the hot tub will go up while filling with the garden hose. The water level in the pool will also go up, but VERY slowly since it can only receive the water that can move through a 1/4" pipe. However, to keep the hot tub full for the long term, you would have to run enough water to also increase the water level in the pool by the full foot that it was low. That is probably a lot of water to be pumped from a water well into your lake.

Wild speculation: If your area has suffered a significant water deficit over the past three years, then there is a lot of aquifer that must be re-filled to bring the level of your lake back up. It may take several years of above average precipitation to get the water level back to where it was three years ago.

Hopefully, you did observe the lake level go up at least a little bit as the winter snows melted off this spring? Likewise, hopefully it goes up a bit within a few days after a big rain, before it starts going down again.

You might consider putting a water gauge just off of your shoreline. You could just mark up a piece of 3/4" PVC pipe and pound it into the sand. Then you can observe the level of your lake at a fine scale. You might also try observing a nearby river or creek to see if there is any correlation to your lake.

There are (many) ways my discussion above could be quite wrong. For example, your lake could be in a restricted aquifer and NOT well-connected to the nearby rivers and streams. However, there might be a sandpit operation two lakes over, and the operator is massively pumping down his lake to increase his sand production. Something like that might significantly affect your lake!

I hope that discussion helps you to understand your situation a little better?

I am sorry to perhaps be the bearer of bad news that there is probably no easy/cheap solution to your problem.

The good news is that there are lots of members in the forum that perform rain dances and rain prayers to send needed precipitation to people with low ponds. You may have to hope that helps you out a little!

Good luck on getting your lake back to its proper elevation.